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Sample records for lead-free piezoelectric ceramics

  1. Characterization of Hard Piezoelectric Lead-Free Ceramics

    PubMed Central

    Zhang, Shujun; Lim, Jong Bong; Lee, Hyeong Jae; Shrout, Thomas R.

    2010-01-01

    K4CuNb8O23 doped K0.45Na0.55NbO3 (KNN-KCN) ferroelectric ceramics were found to exhibit asymmetrical polarization hysteresis loops, related to the development of an internal bias field. The internal bias field is believed to be the result of defect dipoles of acceptor ions and oxygen vacancies, which lead to piezoelectric “hardening” effect, by stabilizing and pinning of the domain wall motion. The dielectric loss for the hard lead-free piezoelectric ceramic was found to be 0.6%, with mechanical quality factors Q on the order of >1500. Furthermore, the piezoelectric properties were found to decrease and the coercive field increased, when compared with the undoped material, exhibiting a typical characteristic of “hard” behavior. The temperature usage range was limited by the polymorphic phase transition temperature, being 188°C. The full set of material constants was determined for the KNN-KCN materials. Compared with conventional hard PZT ceramics, the lead-free possessed lower dielectric and piezoelectric properties; however, comparable values of mechanical Q, dielectric loss, and coercive fields were obtained, making acceptor modified KNN based lead-free piezoelectric material promising for high-power applications, where lead-free materials are desirable. PMID:19686966

  2. KNN-NTK composite lead-free piezoelectric ceramic

    NASA Astrophysics Data System (ADS)

    Matsuoka, T.; Kozuka, H.; Kitamura, K.; Yamada, H.; Kurahashi, T.; Yamazaki, M.; Ohbayashi, K.

    2014-10-01

    A (K,Na)NbO3-based lead-free piezoelectric ceramic was successfully densified. It exhibited an enhanced electromechanical coupling factor of kp = 0.52, a piezoelectric constant d33 = 252 pC/N, and a frequency constant Np = 3170 Hz m because of the incorporation of an elaborate secondary phase composed primarily of KTiNbO5. The ceramic's nominal composition was 0.92K0.42Na0.44Ca0.04Li0.02Nb0.85O3-0.047K0.85Ti0.85Nb1.15O5-0.023BaZrO3-0.0017Co3O4-0.002Fe2O3-0.005ZnO, abbreviated herein as KNN-NTK composite. The KNN-NTK ceramic exhibited a dense microstructure with few microvoids which significantly degraded its piezoelectric properties. Elemental maps recorded using transmission electron microscopy with energy-dispersive X-ray spectroscopy (TEM-EDS) revealed regions of high concentrations of Co and Zn inside the NTK phase. In addition, X-ray diffraction patterns confirmed that a small portion of the NTK phase was converted into K2(Ti,Nb,Co,Zn)6O13 or CoZnTiO4 by a possible reaction between Co and Zn solutes and the NTK phase during a programmed sintering schedule. TEM studies also clarified a distortion around the KNN/NTK interfaces. Such an NTK phase filled voids between KNN particles, resulting in an improved chemical stability of the KNN ceramic. The manufacturing process was subsequently scaled to 100 kg per batch for granulated ceramic powder using a spray-drying technique. The properties of the KNN-NTK composite ceramic produced using the scaled-up method were confirmed to be identical to those of the ceramic prepared by conventional solid-state reaction sintering. Consequently, slight changes in the NTK phase composition and the distortion around the KNN/NTK interfaces affected the KNN-NTK composite ceramic's piezoelectric characteristics.

  3. KNN–NTK composite lead-free piezoelectric ceramic

    SciTech Connect

    Matsuoka, T. Kozuka, H.; Kitamura, K.; Yamada, H.; Kurahashi, T.; Yamazaki, M.; Ohbayashi, K.

    2014-10-21

    A (K,Na)NbO₃-based lead-free piezoelectric ceramic was successfully densified. It exhibited an enhanced electromechanical coupling factor of kₚ=0.52, a piezoelectric constant d₃₃=252 pC/N, and a frequency constant Nₚ=3170 Hz m because of the incorporation of an elaborate secondary phase composed primarily of KTiNbO₅. The ceramic's nominal composition was 0.92K₀.₄₂Na₀.₄₄Ca₀.₀₄Li₀.₀₂Nb₀.₈₅O₃–0.047K₀.₈₅Ti₀.₈₅Nb₁.₁₅O₅–0.023BaZrO₃ –0.0017Co₃O₄–0.002Fe₂O₃–0.005ZnO, abbreviated herein as KNN–NTK composite. The KNN–NTK ceramic exhibited a dense microstructure with few microvoids which significantly degraded its piezoelectric properties. Elemental maps recorded using transmission electron microscopy with energy-dispersive X-ray spectroscopy (TEM–EDS) revealed regions of high concentrations of Co and Zn inside the NTK phase. In addition, X-ray diffraction patterns confirmed that a small portion of the NTK phase was converted into K₂(Ti,Nb,Co,Zn)₆O₁₃ or CoZnTiO₄ by a possible reaction between Co and Zn solutes and the NTK phase during a programmed sintering schedule. TEM studies also clarified a distortion around the KNN/NTK interfaces. Such an NTK phase filled voids between KNN particles, resulting in an improved chemical stability of the KNN ceramic. The manufacturing process was subsequently scaled to 100 kg per batch for granulated ceramic powder using a spray-drying technique. The properties of the KNN–NTK composite ceramic produced using the scaled-up method were confirmed to be identical to those of the ceramic prepared by conventional solid-state reaction sintering. Consequently, slight changes in the NTK phase composition and the distortion around the KNN/NTK interfaces affected the KNN–NTK composite ceramic's piezoelectric characteristics.

  4. Structural, Dielectric, Piezoelectric and Ferroelectric Characterization of NBT-BT Lead-Free Piezoelectric Ceramics

    NASA Astrophysics Data System (ADS)

    Shanmuga Sundari, S.; Kumar, Binay; Dhanasekaran, R.

    2013-05-01

    Lead free piezoelectric 0.94(Na0.5Bi0.5)TiO3-0.06BaTiO3 (NBT-BT) ceramics were synthesized in MPB composition by conventional solid state reaction method. The crystalline nature of NBT-BT ceramic was studied by XRD and the size of the grains are determined by SEM. The X- ray diffraction results reveal that Ba2+ diffuse into the Na0.5 Bi0.5TiO3 lattices to form a solid solution with a pure perovskite structure. Because of the strong ferroelectricity and MPB, the ceramics exhibit high piezoelectric properties: d33 = 206 pC/N. Td (depolarization temperature) and Tm (temperature at with the dielectric constant epsilonr reaches a maximum) were observed through the phase transition in dielectric studies. In addition, the prepared ceramic exhibits relaxor characteristic, which probably results from the cation disordering in the 12fold coordination sites. Pr and Ec of the prepared ceramics were determined from the P-E hysteresis loop.

  5. Structure, microstructure, and piezoelectric properties of ytterbium-doped potassium sodium niobate lead-free ceramics

    NASA Astrophysics Data System (ADS)

    Li, Huan; Yang, Wenlong; Zhou, Zhongxiang; Tian, Hao

    2013-09-01

    The structure, microstructure, and piezoelectric properties of conventionally sintered Yb-doped K0.5Na0.5NbO3 (KNN) lead-free ceramics were investigated. Doping the KNN ceramics with Yb2O3 was effective in inhibiting the grain growth in the KNN ceramics and in densifying the ceramics. The 1.0 wt. % Yb-doped KNN ceramics showed the maximum density, about 96.8% of the theoretical density. X-ray diffraction analysis showed that a small number of Yb3+ ions could be incorporated into the matrix of the ceramicsto occupythe α- or β-sites in the crystal lattice, thereby significantly affecting the piezoelectric properties of the ceramics. Enhanced piezoelectric properties ( i.e., d 33= 135 pC/N, k p = 34.5%, and Q m = 80.2) were obtained for the 0.50 wt. % Yb-doped KNN ceramics.

  6. Lead-free KNLNT piezoelectric ceramics for high-frequency ultrasonic transducer application.

    PubMed

    Wu, D W; Chen, R M; Zhou, Q F; Shung, K K; Lin, D M; Chan, H L W

    2009-03-01

    This paper presents the latest development of a lead-free piezoelectric ceramic and its application to transducers suitable for high-frequency ultrasonic imaging. A lead-free piezoelectric ceramic with formula of (K(0.5)Na(0.5))(0.97)Li(0.03)(Nb(0.9) Ta(0.1))O(3) (abbreviated as KNLNT-0.03/0.10) was fabricated and characterized. The material was found to have a clamped dielectric constant epsilon(33)(S)/epsilon(0)=890, piezoelectric coefficient d(33)=245 pC/N, electromechanical coupling factor k(t)=0.42 and Curie temperature T(c)>300 degrees C. High-frequency (40 MHz) ultrasound transducers were successfully fabricated with the lead-free material. A representative lead-free transducer had a bandwidth of 45%, two-way insertion loss of -18 dB. This performance is comparable to reported performances of popular lead-based transducers. The comparison results suggest that the lead-free piezoelectric material may serve as an alternative to lead-based piezoelectric materials for high-frequency ultrasonic transducer applications. PMID:19121835

  7. Lead-free piezoelectric ceramics and transducers in potassium sodium niobate-solid solution system

    NASA Astrophysics Data System (ADS)

    Marandian-Hagh, Nader

    Lead-free piezoelectric ceramic of (K0.44Na0.52Li 0.04)(Nb0.84Ta0.1Sb0.06)O 3; (KNN-LT-LS) was prepared by two processing routes, namely "Perovskite" and "Mixed oxide". The sensitivity of raw materials to relative humidity of laboratory environment indicated that the powders batching/handling had to be carried out in a controlled atmosphere (e.g. Ar). The electromechanical properties of bulk samples in which batching carried out in Ar atmosphere were significantly higher than those ceramics prepared in the laboratory environment. The electromechanical properties of ceramics were also very sensitive to the oxygen flow rate during sintering. It was realized that oxygen vacancies could be formed in low oxygen flow rate and deteriorate piezoelectric properties of such ceramics. Reduction in oxygen vacancies facilitated domain wall switching and led to higher remnant polarization with lower coercive field. The highest longitudinal coupling (k33) and piezoelectric charge (d33 ) coefficients for perovskite routes at optimized oxygen flow rate of 180cm3/min were 65% and 315pC/N, respectively. The substitution of Ba2+ (0, 0.5, 1, 1.5, and 2 mol%) ion as an A-site donor dopant to this system improved the relative permittivity, longitudinal coupling and piezoelectric charge coefficients. Increase in remnant polarization along with the decline of coercive field indicated that the addition of Ba2+ gave rise to soft characteristics in this ternary system. The effect of 0-2 mol% of copper oxide (CuO) addition to the base composition was increased the grain size and changed the morphology and growth behavior of the grains. Mechanical quality factor was remarkably improved (Qm = 350) upon addition of 2 mol% Cu2+ with dramatic decrease in amount of energy for switching the dipole moments. Single element air-backed transducers made of undoped and 1.0 mol% Ba 2+-KNN-LT-LS, and PZT-4 showed a measured -6dB fractional bandwidth of 36%, 50.4%, and 53.5%, respectively. High frequency lead-free transducer of KNN-LT-LS were also fabricated that showed the fractional bandwidth (-6dB) of 55.3% at center frequency of 23.5 MHz. This close acoustic performance of studied lead-free transducer in regards to PZT-4 transducer showed that the lead-free system could be a good candidate used for imaging and HIFU (High Focused Ultrasound) therapeutic applications.

  8. Improved electrical properties for Mn-doped lead-free piezoelectric potassium sodium niobate ceramics

    NASA Astrophysics Data System (ADS)

    Wang, Lingyan; Ren, Wei; Ma, Wenhui; Liu, Ming; Shi, Peng; Wu, Xiaoqing

    2015-09-01

    The un-doped and doped lead-free piezoelectric potassium sodium niobate (K0.5Na0.5NbO3, KNN) ceramics with different amounts of Mn were prepared. The decreased dielectric losses and the improved electrical properties were observed in the Mn-doped KNN ceramics. However, the variation of electrical properties with the Mn contents was not continuously. The 0.5 mol.% Mn-doped KNN ceramic shows the highest dielectric loss and the worst electrical properties. The KNN ceramics doped with less than and more than 0.5 mol.% Mn all show improved electrical properties. The change of lattice position of Mn ions in KNN ceramics was the main reason. When the Mn content is less than 0.5 mol.%, the Mn ions occupied the cation vacancies in A-site. When the Mn content is higher than 0.5 mol.%, the Mn ions entered B-site of KNN perovskite structure and formed the defect complexes ( MnNb ″ - VO ṡ ṡ ) and ( MnNb ' - VO ṡ ṡ - MnNb ' ). They both led to a lower defect concentration. However, When the Mn content is up to 1.5 mol.%, the electrical properties of KNN ceramic became degraded because of the accumulation of Mn oxides at grain boundaries.

  9. New KNN-based lead-free piezoelectric ceramic for high-frequency ultrasound transducer applications

    NASA Astrophysics Data System (ADS)

    Ou-Yang, Jun; Zhu, Benpeng; Zhang, Yue; Chen, Shi; Yang, Xiaofei; Wei, Wei

    2015-03-01

    Based on new KNN-based piezoelectric material 0.96(K0.48Na0.52)(Nb0.95Sb0.05)O3-0.04Bi0.5(Na0.82K0.18)0.5ZrO3 with a giant d33 of 490, a 37-MHz high-frequency ultrasound needle transducer with the aperture size of 1 mm was successfully fabricated. The obtained transducer had a high electromechanical coupling factor k t of 0.55, a good bandwidth of 56.8 % at -6 dB, and a low insertion loss of -16 dB at the central frequency. Its excellent performance is comparable to lead-containing transducer and is superior to that of any other lead-free transducer. This promising result demonstrates that this new KNN-based lead-free piezoelectric ceramic is a good candidate to replace lead-based materials for high-frequency ultrasound imaging.

  10. Tailoring of unipolar strain in lead-free piezoelectrics using the ceramic/ceramic composite approach

    SciTech Connect

    Khansur, Neamul H.; Daniels, John E.; Groh, Claudia; Jo, Wook; Webber, Kyle G.; Reinhard, Christina; Kimpton, Justin A.

    2014-03-28

    The electric-field-induced strain response mechanism in a polycrystalline ceramic/ceramic composite of relaxor and ferroelectric materials has been studied using in situ high-energy x-ray diffraction. The addition of ferroelectric phase material in the relaxor matrix has produced a system where a small volume fraction behaves independently of the bulk under an applied electric field. Inter- and intra-grain models of the strain mechanism in the composite material consistent with the diffraction data have been proposed. The results show that such ceramic/ceramic composite microstructure has the potential for tailoring properties of future piezoelectric materials over a wider range than is possible in uniform compositions.

  11. Sodium potassium niobate-based lead-free piezoelectric ceramics: Bulk and freestanding thick films

    NASA Astrophysics Data System (ADS)

    Li, Huidong

    2008-10-01

    Due to the toxicity of lead, there is an urgent need to develop lead-free alternatives to replace the currently dominant lead-based piezoelectrics such as lead zirconate titanate (PZT). (Na0.5K0.5)NbO 3 (NKN)-based piezoelectrics are promising because of their relatively high Curie temperatures and piezoelectric coefficients among the non-lead piezoelectrics. However, it is difficult to sinter. In this thesis study, a colloidal coating method was developed to improve the sintering of NKN. With this coating method, NKN with good piezoelectric properties can be produced without cold isostatic pressing. To improve the piezoelectric performance of NKN, we performed antimony (Sb) doping studies for a NKN-LN solid solution using the coating approach. It was found that Sb doping greatly improved the density and the piezoelectric properties of the NKN-LiNbO3 solid solution and optimized performance was found at 4%Sb. The reasons for the improved piezoelectric properties and density were discussed. Recently, a large enhancement in the piezoelectric performance under electric fields was discovered in polycrystalline lead magnesium niobate-lead titanate (PMN-PT) when the material was made into freestanding film geometry. Here, for the first time, we show a similar effect was also observed in a lead-free system, (Na0.5K0.5)0.945Li0.055Nb 0.96Sb0.04O3. At 6-8 kV/cm, a giant --d 31 value of 1700 pm/V was achieved, 20 times higher than the value of bulk counterpart. The enhancement was found to result from the ease of domain motion imparted by the freestanding film geometry, and the magnitude of the enhancement can be affected by the electrode layer (a non-piezoelectric) thickness. The freestanding geometry provides a new approach to greatly improve the piezoelectric performance of the current lead-free systems.

  12. Giant piezoelectricity in potassium-sodium niobate lead-free ceramics.

    PubMed

    Wang, Xiaopeng; Wu, Jiagang; Xiao, Dingquan; Zhu, Jianguo; Cheng, Xiaojing; Zheng, Ting; Zhang, Binyu; Lou, Xiaojie; Wang, Xiangjian

    2014-02-19

    Environment protection and human health concern is the driving force to eliminate the lead from commercial piezoelectric materials. In 2004, Saito et al. [ Saito et al., Nature , 2004 , 432 , 84 . ] developed an alkali niobate-based perovskite solid solution with a peak piezoelectric constant d33 of 416 pC/N when prepared in the textured polycrystalline form, intriguing the enthusiasm of developing high-performance lead-free piezoceramics. Although much attention has been paid on the alkali niobate-based system in the past ten years, no significant breakthrough in its d33 has yet been attained. Here, we report an alkali niobate-based lead-free piezoceramic with the largest d33 of ?490 pC/N ever reported so far using conventional solid-state method. In addition, this material system also exhibits excellent integrated performance with d33?390-490 pC/N and TC?217-304 C by optimizing the compositions. This giant d33 of the alkali niobate-based lead-free piezoceramics is ascribed to not only the construction of a new rhombohedral-tetragonal phase boundary but also enhanced dielectric and ferroelectric properties. Our finding may pave the way for "lead-free at last". PMID:24499419

  13. Piezoelectric/photoluminescence effects in rare-earth doped lead-free ceramics

    NASA Astrophysics Data System (ADS)

    Yao, Qirong; Wang, Feifei; Jin, Chengchao; Tang, Yanxue; Wang, Tao; Shi, Wangzhou

    2013-10-01

    In the present work, we report the environmentally-friendly multifunctional effects—piezoelectric/photoluminescence effects, which originated from the combination of the electromechanical properties and the photoluminescence effect through introducing the rare-earth elements (Pr and Eu) into the (Bi0.5Na0.5)TiO3-BaTiO3 ceramics with the composition around the morphotropic phase boundary. Compared to the pure piezoelectric ceramic, the proposed system simultaneously exhibited enhanced ferroelectric, piezoelectric, dielectric properties along with strong photoluminescence effects, which exhibited potential applications in sensor, and electro-mechano-optical integration. In addition, the present work also provides a promising path for us to fabricate multifunctional composites.

  14. Phase transition characteristics and associated piezoelectricity of potassium-sodium niobate lead-free ceramics.

    PubMed

    Wang, Yuanyu; Hu, Liang; Zhang, Qilong; Yang, Hui

    2015-08-14

    To achieve high piezoelectric activity and a wide sintering temperature range, the ceramic system concerning (1 - x)(K(0.48)Na(0.52))(Nb(0.96)Sb(0.04))O(3)-x[Bi(0.5)(Na(0.7)Ag(0.3))(0.5)](0.90) Zn(0.10)ZrO(3) was designed, and the rhombohedral-tetragonal (R-T) phase boundary can drive a high d(33). Phase transition characteristics as well as their effects on the electrical properties were investigated systematically. The R-T coexistence phase boundary (0.04 ? x ? 0.05) can be driven via modification with BNAZZ, and has been confirmed by XRD and temperature-dependent dielectric constants as well as Raman analysis, and the ceramics possess enhanced piezoelectric properties (d(33) ? 425 pC N(-1) and k(p) ? 0.43) and a high unipolar strain (?0.3%). In addition, a wide sintering temperature range of 1050-1080 C can warrant a large d(33) of 400-430 pC N(-1), which can benefit practical applications. As a result, the addition of BNAZZ is an effective method to improve the electrical properties (piezoelectricity and strain) and sintering behavior of potassium-sodium niobate ceramics. PMID:26150357

  15. Effect of poling process on piezoelectric properties of BCZT - 0.08 wt.% CeO2 lead-free ceramics

    NASA Astrophysics Data System (ADS)

    Chandrakala, E.; Praveen, J. Paul; Das, Dibakar

    2016-05-01

    The properties of lead free piezoelectric materials can be tuned by suitable doping in the A and B sites of the perovskite structure. In the present study, cerium has been identified as a dopant to investigate the piezoelectric properties of lead-free BCZT system. BCZT - 0.08 wt.%CeO2 lead-free ceramics have been synthesized using sol-gel technique and the effects of CeO2 dopant on their phase structure and piezoelectric properties were investigated systematically. Poling conditions, such as temperature, electric field, and poling time have been optimized to get enhanced piezoelectric response. The optimized poling conditions (50°C, 3Ec and 30min) resulted in high piezoelectric charge coefficient d33 ~ 670pC/N, high electromechanical coupling coefficient kp ~ 60% and piezoelectric voltage coefficient g33 ~ 14 mV.m/N for BCZT - 0.08wt.% CeO2 ceramics.

  16. Effect of orthorhombic-tetragonal phase transition on structure and piezoelectric properties of KNN-based lead-free ceramics.

    PubMed

    Zhang, Yang; Li, Lingyu; Shen, Bo; Zhai, Jiwei

    2015-05-01

    (1 - x)(K0.5Na0.5)0.95Li0.05Nb0.93Sb0.07O3-xSrZrO3 ((1 - x)KNLNS-xSZ) lead free piezoelectric ceramics have been prepared by the conventional solid state reaction method, via adjusting the orthorhombic-tetragonal phase transition temperature to near room temperature with doping SrZrO3, and the effects of SrZrO3 content on polymorphic phase transition have been investigated. These results show that the phase structure of the ceramics was changed from orthorhombic to tetragonal at x ≥ 0.02 mol, and the orthorhombic-tetragonal phase transition temperature was modified to around room temperature with increasing SrZrO3. Remarkable piezoelectric and ferroelectric properties has been obtained in (1 - x)KNLNS-xSZ system with x = 0.02, which showed a piezoelectric parameter of d33 = 256 pC N(-1), Curie temperature Tc = 270 °C, strain levels of 0.16% at 50 kV cm(-1), remnant polarization Pr = 24.9 μC cm(-2) and coercive field Ec = 10.6 kV cm(-1). PMID:25813211

  17. Effects of improved process for CuO-doped NKN lead-free ceramics on high-power piezoelectric transformers.

    PubMed

    Yang, Song-Ling; Tsai, Cheng-Che; Liou, Yi-Cheng; Hong, Cheng-Shong; Li, Bing-Jing; Chu, Sheng-Yuan

    2011-12-01

    In this paper, the effects of the electrical proper- ties of CuO-doped (Na(0.5)K(0.5))NbO(3) (NKN) ceramics prepared separately using the B-site oxide precursor method (BO method) and conventional mixed-oxide method (MO method) on high-power piezoelectric transformers (PTs) were investigated. The performances of PTs made with these two substrates were compared. Experimental results showed that the output power and temperature stability of PTs could be enhanced because of the lower resonant impedance of the ceramics prepared using the BO method. In addition, the output power of PTs was more affected by the resonant impedance than by the mechanical quality factor (Q(m)) of the ceramics. The PTs fabricated with ceramics prepared using the BO method showed a high efficiency of more than 94% and a maximum output power of 8.98 W (power density: 18.3 W/cm(3)) with temperature increase of 3C under the optimum load resistance (5 k?) and an input voltage of 150 V(pp). This output power of the lead-free disk-type PTs is the best reported so far. PMID:23443691

  18. Lead-Free Metamaterials with Enormous Apparent Piezoelectric Response.

    PubMed

    Zhou, Wanfeng; Chen, Pan; Pan, Qi; Zhang, Xiaotong; Chu, Baojin

    2015-11-01

    Lead-free flexoelectric piezoelectric metamaterials are created by applying an asymmetric chemical reduction to Na1/2 Bi1/2 TiO3 -BaTiO3 ceramics. The reduction induces two gradient-generating mechanisms, curvature structure and chemical inhomogeneity, and enhances the flexoelectric effect. The ceramics behave like piezoelectric materials, exhibiting an enormous and high-temperature stable apparent piezoelectric response, outperforming existing lead-oxide-based piezoelectrics. PMID:26401646

  19. Synthesis of lead-free piezoelectric powders by ultrasonic-assisted hydrothermal method and properties of sintered (K0.48Na0.52)NBO3 ceramics.

    PubMed

    Isobe, Gaku; Maeda, Takafumi; Bornmann, Peter; Hemsel, Tobias; Morita, Takeshi

    2014-02-01

    (K,Na)NbO3 ceramics have attracted much attention as lead-free piezoelectric materials with high piezoelectric properties. High-quality (K,Na)NbO3 ceramics can be sintered using KNbO3 and NaNbO3 powders synthesized by a hydrothermal method. In this study, to enhance the quality factor of the ceramics, high-power ultrasonic irradiation was employed during the hydrothermal method, which led to a reduction in the particle size of the resultant powders. PMID:24474129

  20. A comparison of different powder compaction processes adopted for synthesis of lead-free piezoelectric ceramics

    NASA Astrophysics Data System (ADS)

    Mahesh, M. L. V.; Bhanu Prasad, V. V.; James, A. R.

    2016-04-01

    Barium zirconium titanate, Ba(Zr0.15Ti0.85)O3 nano-crystalline powders were synthesized using high energy ball milling. The calcined powders were compacted adopting two different approaches viz. the conventional uniaxial pressing and cold-isostatic pressing (CIP) and the compacts were sintered at 1350 °C. A single phase perovskite structure was observed in both cases. BZT ceramics compacted using CIP technique exhibited enhanced dielectric and ferroelectric properties compared to ceramics compacted by uniaxial pressing. The polarization current peaks have been used in this paper as an experimental evidence to prove the existence of ferroelectricity in the BZT ceramics under study. The peak polarization current was found to be ~700% higher in case of cold iso-statically compacted ceramics. Similarly electric field induces strain showed a maximum strain ( S max) of 0.08% at an electric field of 28 kV/cm. The dielectric and ferroelectric properties observed are comparable to single crystals of the same material.

  1. Lead-free multilayer piezoelectric transformer.

    PubMed

    Guo, Mingsen; Jiang, X P; Lam, K H; Wang, S; Sun, C L; Chan, Helen L W; Zhao, X Z

    2007-01-01

    In this article, a multilayer piezoelectric transformer based on lead-free Mn-doped 0.94(Bi(12)Na(12))TiO(3)-0.06BaTiO(3) ceramics is presented. This piezoelectric transformer, with a multilayered construction in the thickness direction, is 8.3 mm long, 8.3 mm wide, and 2.3 mm thick. It operates in the second thickness extensional vibration mode. For a temperature rise of 20 degrees C, the transformer has an output power of >0.3 W. With a matching load resistance of 10 Omega, its maximum efficiency approaches 81.5%, and the maximum voltage gain is 0.14. It has potential to be used in low voltage power supply units such as low power adapter and other electronic circuits. PMID:17503954

  2. Phase Structure, Piezoelectric and Multiferroic Properties of SmCoO3-Modified BiFeO3-BaTiO3 Lead-Free Ceramics

    NASA Astrophysics Data System (ADS)

    Jiang, Na; Tian, Mijie; Luo, Lingling; Zheng, Qiaoji; Shi, Dongliang; Lam, Kwok Ho; Xu, Chenggang; Lin, Dunmin

    2016-01-01

    (0.75- x)BiFeO3-0.25BaTiO3- xSmCoO3 + 1 mol.% MnO2 lead-free multiferroic ceramics were synthesized by a conventional ceramic fabrication technique. The effects of SmCoO3 on phase structure, piezoelectricity and multiferroicity of the ceramics were studied. All the ceramics can be well sintered at a low sintering temperature of 960°C. The crystalline structure of the ceramics is transformed from rhombohedral to tetragonal symmetry with increasing the amount of SmCoO3. A morphotropic phase boundary of rhombohedral and tetragonal phases is formed at x = 0.01-0.04. A small amount of SmCoO3 is shown to improve the ferroelectric, piezoelectric and magnetoelectric properties of the ceramics. For the ceramics with x = 0.01-0.03, enhanced resistivity ( R ˜ 1.2 × 109 Ω cm to 2.1 × 109 Ω cm), piezoelectricity ( d 33 ˜ 65 pC/N to 106 pC/N) and ferroelectricity ( P r ˜ 6.38 μC/cm2 to 22.89 μC/cm2) are obtained. The ferromagnetism of the materials is greatly enhanced by the doping of SmCoO3 such that a very high magnetoelectric coefficient of ˜742 mV/(cm Oe) is obtained at x = 0.01, suggesting a promising potential in multiferroic devices.

  3. Piezoelectric and ferroelectric properties of Bi-compensated (Bi1/2Na1/2)TiO3-(Bi1/2K1/2)TiO3 lead-free piezoelectric ceramics

    NASA Astrophysics Data System (ADS)

    Zhang, Ya-Ru; Li, Jing-Feng; Zhang, Bo-Ping; Peng, Chun-E.

    2008-04-01

    (Bi1/2Na1/2)TiO3-(Bi1/2K1/2)TiO3 (BNT-BKT) ceramics as a promising candidate for lead-free piezoelectric ceramics were studied with a special emphasis on the compositional dependence of piezoelectric and ferroelectric properties. One mole percent excess Bi was added to compensate for the volatilization of Bi3+ ions during sintering, which was found to be effective in improving the piezoelectric properties of the resultant BNT-BKT ceramics. The piezoelectric, ferroelectric, and dielectric properties of the Bi-compensated BNT-BKT ceramics were investigated and discussed in relation to the morphotropic phase boundary that is close to the composition range of 20-24 mol % BKT. The maximum piezoelectric constant d33 (207 pC/N) and electromechanical coupling factor kp (35%) were obtained at the compositions of 23% and 20%, respectively.

  4. Effects of Li Substitution and Sintering Temperature on Properties of Bi0.5(Na, K)0.5 TiO3 Lead-Free Piezoelectric Ceramics

    NASA Astrophysics Data System (ADS)

    Ming, Bao-Quan; Wang, Jin-Feng; Zang, Guo-Zhong

    2008-10-01

    Bi0.5(Na0.72 K0.28-xLix)0.5TiO3 (BNKLT-1OOx) lead-free piezoelectric ceramics are synthesized by conventional solid state sintering techniques. The dielectric and piezoelectric properties of the BNKLT-1OOx ceramics as a function of Li content are systematically investigated. It is found that not only Li content but also the sintering temperature has a strong effect on the piezoelectric properties of BNKLT. The piezoelectric constant d33 of BNKLT varies from 120 to 252pC/N in the Li content range from 0.03 to 0.16. In the sintering temperature range from 1080 to 1130° C, the d33 value of BNKLT-6 changes from 200pC/N to 252pC/N. The BNKLT-6 sample sintered at 1100° C has the highest piezoelectric constant d33 of 252pC/N, with the electromechanical coupling factors kp of 0.32 and kt of 0.44.

  5. Manufacture and Cytotoxicity of a Lead-free Piezoelectric Ceramic as a Bone Substitute—Consolidation of Porous Lithium Sodium Potassium Niobate by Cold Isostatic Pressing

    PubMed Central

    Wang, Qi; Yang, Jun; Zhang, Wu; Khoie, Roxanne; Li, Yi-ming; Zhu, Jian-guo; Chen, Zhi-qing

    2009-01-01

    Aim The piezoelectric properties and cytotoxicity of a porous lead-free piezoelectric ceramic for use as a direct bone substitute were investigated. Methodology Cold isostatic pressing (CIP) was applied to fabricate porous lithium sodium potassium niobate (Li0.06Na0.5K0.44) NbO3 specimens using a pore-forming method. The morphologies of the CIP-processed specimens were characterized and compared to those of specimens made by from conventional pressing procedures. The effects of the ceramic on the attachment and proliferation of osteoblasts isolated from the cranium of 1-day-old Sprague-Dawley rats were examined by a scanning electron microscopy (SEM) and methylthiazol tetrazolium (MTT) assay. Results The results showed that CIP enhanced piezoelectricity and biological performance of the niobate specimen, and also promoted an extracellular matrix-like topography of it. In vitro studies showed that the CIP-enhanced material had positive effects on the attachment and proliferation of osteoblasts. Conclusion Niobate ceramic generated by CIP shows a promise for being a piezoelectric composite bone substitute. PMID:20687302

  6. Fabrication of high-power piezoelectric transformers using lead-free ceramics for application in electronic ballasts.

    PubMed

    Yang, Song-Ling; Chen, Shih-Ming; Tsai, Cheng-Che; Hong, Cheng-Shong; Chu, Sheng-Yuan

    2013-02-01

    CuO is doped into (Na(0.5)K(0.5))NbO(3) (NKN) ceramics to improve the piezoelectric properties and thus obtain a piezoelectric transformer (PT) with high output power. In X-ray diffraction patterns, the diffraction angles of the CuO-doped NKN ceramics shift to lower values because of an expansion of the lattice volume, thus inducing oxygen vacancies and enhancing the mechanical quality factor. A homogeneous microstructure is obtained when NKN is subjected to CuO doping, leading to improved electrical properties. PTs with different electrode areas are fabricated using the CuO-doped NKN ceramics. Considering the efficiency, voltage gain, and temperature rise of PTs at a load resistance of 1 kΩ, PTs with an electrode with an inner diameter of 15 mm are combined with the circuit design for driving a 13-W T5 fluorescent lamp. A temperature rise of 6°C and a total efficiency of 82.4% (PT and circuit) are obtained using the present PTs. PMID:23357915

  7. Phase transition behavior and electrical properties of lead-free (Ba1-xCax)(Zr0.1Ti0.9)O3 piezoelectric ceramics

    NASA Astrophysics Data System (ADS)

    Tian, Ye; Chao, Xiaolian; Wei, Lingling; Liang, Pengfei; Yang, Zupei

    2013-05-01

    Lead-free (Ba1-xCax)(Zr0.1Ti0.9)O3(BCZT) ceramics were synthesized by conventional solid-state sintering process. The Ca ion substitutions on phase transition behavior, microstructure, ferroelectric and piezoelectric properties of BCZT ceramics were systemically investigated. The diffuse phase transition (DPT) behavior was suppressed, while the orthorhombic → tetragonal (O→T) and rhombohedral → orthorhombic (R→O) phase transitions were observed when the Ca content is at x = 0.05. Further increasing the Ca content, the DPT behavior gradually enhanced, and both the O→T and R→O phase transitions gradually evolved into R→T phase transition when the Ca content increases up to 0.15 at 25 °C. This behavior was related with phase structure and morphology, which significantly impacted the ferroelectric and piezoelectric properties near the R→T phase boundary. As a result, the sample with Ca contents of 0.15 shows the outstanding piezoelectric properties (with d33 = 572 pC/N, kp = 57%, Qm = 125, ɛr = 4821, and tan δ = 0.015) while negligible change for the ferroelectric properties. The abnormal ferroelectric behavior and potential factor contributing to large piezoelectric response also were discussed.

  8. Effect of poling temperature on piezoelectricity of CaZrO3-modified (K, Na)NbO3-based lead-free ceramics

    NASA Astrophysics Data System (ADS)

    Yao, Fang-Zhou; Wang, Ke; Jo, Wook; Lee, Jae-Shin; Li, Jing-Feng

    2014-09-01

    Electrical poling is indispensable for endowing isotropic ferroelectric polycrystals with a net macroscopic polarization and hence piezoelectricity. However, little attention has been paid to the optimization of poling conditions in (K, Na)NbO3-based ceramics with a polymorphic phase transition. This study investigated the electrical properties of CaZrO3-modified (K, Na, Li)(Nb, Ta)O3 lead-free piezoceramics as a function of the poling temperature. Peak piezoelectric coefficient d33 of 352 7 pC/N and planar electromechanical coupling factor kp of 0.47 were obtained at the optimized poling temperature of 120 C, which crosses the polymorphic phase transition regime. In-depth analysis of the asymmetric polarization hysteresis loops and bipolar strain curves uncovered striking analogy between electrical poling and unipolar cycling in the current system, which is attributed to a competition between domain reorientation and space charge accumulation.

  9. Improvement of the piezoelectric properties in (K,Na)NbO3-based lead-free piezoelectric ceramic with two-phase co-existing state

    NASA Astrophysics Data System (ADS)

    Yamada, H.; Matsuoka, T.; Kozuka, H.; Yamazaki, M.; Ohbayashi, K.; Ida, T.

    2015-06-01

    Two phases of (K,Na)NbO3 (KNN) co-exist in a KNN-based composite lead-free piezoelectric ceramic 0.910(K1-xNax)0.86Ca0.04Li0.02Nb0.85O3-δ-0.042K0.85Ti0.85Nb1.15O5-0.036BaZrO3-0.0016Co3O4- 0.0025Fe2O3-0.0069ZnO system, over a wide range of Na fractions, where 0.56 ≤ x ≤ 0.75. The crystal systems of the two KNN phases are identified to tetragonal and orthorhombic by analyzing the synchrotron powder X-ray diffraction (XRD) data, high-resolution transmission electron microscopy (HR-TEM), and selected-area electron diffraction (SAD). In the range 0.33 ≤ x ≤ 0.50, the main component of the composite system is found to be single-phase KNN with a tetragonal structure. Granular nanodomains of the orthorhombic phase dispersed in the tetragonal matrix have been identified by HR-TEM and SAD for 0.56 ≤ x ≤ 0.75. Only a trace amount of the orthorhombic phase has been found in the SAD patterns at the composition x = 0.56. However, the number of orthorhombic nanodomains gradually increases with increasing Na content up to x < 0.75, as observed from the HR-TEM images. An abrupt increase and agglomeration of the nanodomains are observed at x = 0.75, where weak diffraction peaks of the orthorhombic phase have also become detectable from the XRD data. The maximum value of the electromechanical coupling coefficient, kp = 0.56, has been observed at the composition x = 0.56.

  10. Lead-free piezoelectric ceramics derived from the K0.5Na0.5NbO3-AgNbO3 solid solution system

    NASA Astrophysics Data System (ADS)

    Lei, Chao; Ye, Zuo-Guang

    2008-07-01

    A lead-free solid solution between potassium sodium niobate and silver niobate, (1-x)K0.5Na0.5NbO3-xAgNbO3 (KNN-AN, with x =0-0.36), has been prepared in the form of ceramics by solid state reaction under O2 atmosphere. The crystal chemical study shows that Ag+ ion diffuses into the KNN lattices to form a solid solution of perovskite structure with x up to 0.30. The substitution of Ag+ ion for (K0.5Na0.5)+ ion results in linear decreases in the ferroelectric Curie temperature (TC), from 420°C in KNN down to 325°C in 0.70KNN-0.30AN, and in the tetragonal to orthorhombic phase transition temperature (TT-O), from 190 down to 150°C. The relative density of the KNN-AN ceramics reaches 94%. The optimum piezoelectric properties are found in the ceramics of 0.82KNN-0.18AN, with a piezocoefficient d33=186pC /N, an electromechanical coupling factor kp=42.5%, and a TC=355°C. For the ceramics with x =0.24, the remanent polarization reaches a maximum value of Pr=20μC/cm2, with a reduced coercive field Ec=6.4kV/cm and a TC=340°C. It is shown that the (1-x)KNN-xAN ceramics exhibit piezoelectric properties which are comparable or superior to the hot-pressed KNN ceramics and other KNN-based systems. In particular, the piezoelectric properties exhibit very a good thermal stability up to high temperature, which is a significant improvement from other KNN-based piezoceramics.

  11. Enhanced piezoelectricity and nature of electric-field induced structural phase transformation in textured lead-free piezoelectric Na0.5Bi0.5TiO3-BaTiO3 ceramics

    NASA Astrophysics Data System (ADS)

    Maurya, Deepam; Pramanick, Abhijit; An, Ke; Priya, Shashank

    2012-04-01

    This letter provides a comparative description of the properties of textured and randomly oriented poly-crystalline lead-free piezoelectric 0.93(Na0.5Bi0.5TiO3)-0.07BaTiO3 (NBT-BT) ceramics. A high longitudinal piezoelectric constant of (d33) ˜ 322 pC/N was obtained in (001)PC textured NBT-7BT ceramics, which is almost ˜2× times the d33 coefficient reported for randomly oriented ceramics of the same composition. In situ neutron diffraction experiments revealed that characteristically different structural responses are induced in textured and randomly oriented NBT-BT ceramics upon application of electric fields (E), which are likely related to the varying coherence lengths of polar nanoregions and internal stresses induced by domain switching.

  12. Improvement of the piezoelectric properties in (K,Na)NbO{sub 3}-based lead-free piezoelectric ceramic with two-phase co-existing state

    SciTech Connect

    Yamada, H. Matsuoka, T.; Kozuka, H.; Yamazaki, M.; Ohbayashi, K.; Ida, T.

    2015-06-07

    Two phases of (K,Na)NbO{sub 3} (KNN) co-exist in a KNN-based composite lead-free piezoelectric ceramic 0.910(K{sub 1−x}Na{sub x}){sub 0.86}Ca{sub 0.04}Li{sub 0.02}Nb{sub 0.85}O{sub 3−δ}–0.042K{sub 0.85}Ti{sub 0.85}Nb{sub 1.15}O{sub 5} –0.036BaZrO{sub 3}–0.0016Co{sub 3}O{sub 4}– 0.0025Fe{sub 2}O{sub 3}–0.0069ZnO system, over a wide range of Na fractions, where 0.56 ≤ x ≤ 0.75. The crystal systems of the two KNN phases are identified to tetragonal and orthorhombic by analyzing the synchrotron powder X-ray diffraction (XRD) data, high-resolution transmission electron microscopy (HR-TEM), and selected-area electron diffraction (SAD). In the range 0.33 ≤ x ≤ 0.50, the main component of the composite system is found to be single-phase KNN with a tetragonal structure. Granular nanodomains of the orthorhombic phase dispersed in the tetragonal matrix have been identified by HR-TEM and SAD for 0.56 ≤ x ≤ 0.75. Only a trace amount of the orthorhombic phase has been found in the SAD patterns at the composition x = 0.56. However, the number of orthorhombic nanodomains gradually increases with increasing Na content up to x < 0.75, as observed from the HR-TEM images. An abrupt increase and agglomeration of the nanodomains are observed at x = 0.75, where weak diffraction peaks of the orthorhombic phase have also become detectable from the XRD data. The maximum value of the electromechanical coupling coefficient, k{sub p} = 0.56, has been observed at the composition x = 0.56.

  13. Ultrahigh strain response with fatigue-free behavior in (Bi0.5Na0.5)TiO3-based lead-free piezoelectric ceramics

    NASA Astrophysics Data System (ADS)

    Hao, Jigong; Xu, Zhijun; Chu, Ruiqing; Li, Wei; Du, Juan; Li, Guorong

    2015-12-01

    In this letter, we report a lead-free piezoelectric ceramic system (Bi0.5Na0.5)1-x Ba x Ti0.98 (Fe0.5Sb0.5)0.02O3 which shows a surprisingly high field-induced nonlinear strain of 0.57% comparable to those obtained in Pb-based antiferroelectrics. The ultrahigh strain response of the composition stems from the composition proximity to the ferroelectric-nonpolar phase boundary, which leads to reversible transformation between a nonpolar phase and a polar ferroelectric phase under cyclic fields. In particular, this material is very attractive for its exceptionally good fatigue resistance (up to 106 cycles) and high temperature stability (25-100 °C) due to its stable nonpolar phase and lower defect density. These findings render the current material a great opportunity for novel applications in ultra-large stroke and nonlinear actuators demanding improved cycling and thermal reliabilities.

  14. The Effects of Ta Substitution and K/Na Ratio Variation on the Microstructure and Properties of (K,Na)NbO3-Based Lead Free Piezoelectric Ceramics

    NASA Astrophysics Data System (ADS)

    Shang, Xunzhong; Guo, Jinming; Xiao, Wanping; Lu, Yinmei; Chang, Gang; Zhou, Taosheng; He, Yunbin

    2014-05-01

    [(Na0.5+ y K0.5- y )0.94Li0.06][(Nb0.94Sb0.06)1- x Ta x ]O3 + 0.08 mol% MnO2 lead-free piezoelectric ceramics were fabricated successfully by a conventional solid-state reaction method. The effects of Ta5+ substitution and K/Na ratio variation on the microstructure and properties of the ceramics have been systematically investigated. With the increasing of Ta5+ substitution content, the orthorhombic-tetragonal transition temperature T o-t presents obvious "V" type variation while the Curie temperature T c decreases monotonically. The ceramics properties were further enhanced by adjusting the Na/K ratio of the A-site. Under systematical optimization of the A-site and B-site elements, good overall electrical properties of d 33 = 276 pC/N, k p = 44.5%, ɛ {33/ T }/ ɛ 0 = 1,175, tan δ = 0.027, T c = 309 °C, P r = 21.0 μC/cm2, and E c = 1.14 kV/mm were obtained for ceramics with Ta5+ content x of 0.05 and Na/K ratio of 57/43 ( y = 0.07).

  15. Reactive sintering of (K0.5Bi0.5)TiO3-BiFeO3 lead-free piezoelectric ceramics

    NASA Astrophysics Data System (ADS)

    Fisher, John G.; Kim, Min-Gu; Kim, Daeung; Cha, Su-Jeong; Vu, Hung Van; Nguyen, Dieu; Kim, Young-Hun; Moon, Su-Hyun; Lee, Jong-Sook; Hussain, Ali; Kim, Myong-Ho

    2015-05-01

    Ceramics based on BiFeO3 are potential lead-free replacements for Pb(Zr,Ti)O3 in a variety of applications such as sensors, transducers and actuators. Recently, ceramics in the (K0.5Bi0.5)TiO3-BiFeO3 system were developed which have excellent piezoelectric properties. However, these ceramics are difficult to sinter to high density. The present work studies the use of reactive sintering to prepare 0.4(K0.5Bi0.5)TiO3-0.6BiFeO3 ceramics. Undoped and MnO-doped powders were prepared by ball milling K2CO3, (BiO)2CO3, TiO2, α-FeO(OH) and MnCO3 in ethanol with zirconia milling media. The decomposition and calcination reactions of the starting materials were studied using differential scanning calorimetry/thermogravimetric analysis, X-ray diffraction and Fourier transform infra-red analysis. Samples were sintered in the temperature range from 1000 to 1075°C and their structures and microstructures examined using X-ray diffraction, micro-Raman scattering and scanning electron microscopy. MnO doping reduced the rhombohedral distortion of the unit cell. The dielectric, ferroelectric and piezoelectric properties of selected undoped and MnO-doped samples were measured. Both undoped and MnO-doped samples displayed relaxor-type behavior. MnO doping reduced the conductivity of the samples, which exhibit a well-defined activation energy of 1.21 eV. Undoped samples have strain vs. electric field properties comparable to those reported in the literature.

  16. Electric field-induced giant strain and photoluminescence-enhancement effect in rare-earth modified lead-free piezoelectric ceramics.

    PubMed

    Yao, Qirong; Wang, Feifei; Xu, Feng; Leung, Chung Ming; Wang, Tao; Tang, Yanxue; Ye, Xiang; Xie, Yiqun; Sun, Dazhi; Shi, Wangzhou

    2015-03-11

    In this work, an electric field-induced giant strain response and excellent photoluminescence-enhancement effect was obtained in a rare-earth ion modified lead-free piezoelectric system. Pr(3+)-modified 0.93(Bi0.5Na0.5)TiO3-0.07BaTiO3 ceramics were designed and fabricated by a conventional fabrication process. The ferroelectric, dielectric, piezoelectric, and photoluminescence performances were systematically studied, and a schematic phase diagram was constructed. It was found the Pr(3+) substitution induced a transition from ferroelectric a long-range order structure to a relaxor pseudocubic phase with short-range coherence structure. Around a critical composition of 0.8 mol % Pr(3+), a giant reversible strain of ?0.43% with a normalized strain Smax/Emax of up to 770 pm/V was obtained at ?5 kV/mm. Furthermore, the in situ electric field enhanced the photoluminescence intensity by ?40% in the proposed system. These findings have great potential for actuator and multifunctional device applications, which may also open up a range of new applications. PMID:25664585

  17. Effect of domain structure on the mechanical and piezoelectric properties of lead-free alkali niobate ceramics

    NASA Astrophysics Data System (ADS)

    Martin, Alexander; Kakimoto, Ken-ichi

    2014-09-01

    Load-bearing applications, such as actuators, require sufficient mechanical properties to guarantee long lifetime and reliability. Lead zirconate titanate (PZT) ceramics show relatively low mechanical strength which decreases after applying an electric field. Thus far, evaluations of the mechanical properties have not been the focus in the case of alkali niobate-based (NKN) ceramics. For this purpose, differently poled Lix(Na0.5K0.5)1-xNbO3 ceramics have been observed by means of 3-point bending tests. Best results were achieved with Li0.02Na0.49K0.49NbO3, with a flexural strength of 115 MPa in unpoled state. This value was maximized at a 90° domain switching fraction η of about 20% to 134 MPa. Other compositions showed similar behavior, which led to the idea that domain switching can be used to enhance the mechanical properties of NKN ceramics. Internal stresses induced via domain reorientation might be the cause of this phenomenon and will be examined in this study.

  18. Lead-Free Piezoelectric Ceramics with Large Dielectric and Piezoelectric Constants Manufactured from BaTiO3 Nano-Powder

    NASA Astrophysics Data System (ADS)

    Karaki, Tomoaki; Yan, Kang; Miyamoto, Toshiyuki; Adachi, Masatoshi

    2007-02-01

    Barium titanate (BaTiO3) ceramics with a density of more than 98% of the theoretical value were fabricated by two-step sintering method from hydrothermally synthesized BaTiO3 nano-particles of 100 nm. The average grain size was around 1.6 μm and the biggest one was controlled less than 3 μm. Dielectric constant ɛr33T of the poled samples was 5000 and electromechanical coupling factor kp was 42%. Large piezoelectric constants d33 = 460 pC/N and d31 = -185 pC/N were measured by a d33-meter and the resonance-antiresonance method, respectively. A high Poisson’s ratio σ = 0.38 was determined from the ratio of overtone frequency and resonant frequency in the planar mode. The high Poisson’s ratio and the large dielectric constants are most likely the origin of the high d33 of the ceramics. The discovery of high d33 in non-lead-based BaTiO3 ceramics with low cost process has important practical consequences in addition to scientific interest.

  19. Bright reddish-orange emission and good piezoelectric properties of Sm2O3-modified (K0.5Na0.5)NbO3-based lead-free piezoelectric ceramics

    NASA Astrophysics Data System (ADS)

    Hao, Jigong; Xu, Zhijun; Chu, Ruiqing; Li, Wei; Du, Juan

    2015-05-01

    Reddish orange-emitting 0.948(K0.5Na0.5)NbO3-0.052LiSbO3-xmol%Sm2O3 (KNN-5.2LS-xSm2O3) lead-free piezoelectric ceramics with good piezoelectric properties were fabricated in this study, and the photoluminescence and electrical properties of the ceramics were systematically studied. Results showed that Sm2O3 substitution into KNN-5.2LS induces a phase transition from the coexistence of orthorhombic and tetragonal phases to a pseudocubic phase and shifts the polymorphic phase transition (PPT) to below room temperature. The temperature stability and fatigue resistance of the modified ceramics were significantly improved by Sm2O3 substitution. The KNN-5.2LS ceramic with 0.4 mol. % Sm2O3 exhibited temperature-independent properties (25-150 °C), fatigue-free behavior (up to 106 cycles), and good piezoelectric properties (d33* = 230 pm/V, d33 = 176 pC/N, kp = 35%). Studies on the photoluminescence properties of the samples showed strong reddish-orange emission upon blue light excitation; these emission intensities were strongly dependent on the doping concentration and sintering temperature. The 0.4 mol. % Sm2O3-modified sample exhibited temperature responses over a wide temperature range of 10-443 K. The maximum sensing sensitivity of the sample was 7.5 × 10-4 K at 293 K, at which point PPT occurred. A relatively long decay lifetime τ of 1.27-1.40 ms and a large quantum yield η of 0.17-0.19 were obtained from the Sm-modified samples. These results suggest that the KNN-5.2LS-xSm2O3 system presents multifunctional properties and significant technological potential in novel multifunctional devices.

  20. Enhanced piezoelectricity and photoluminescence in Dy-doped Ba0.85Ca0.15Ti0.9Zr0.1O3 lead-free multifunctional ceramics

    NASA Astrophysics Data System (ADS)

    Lei, Fengying; Jiang, Na; Luo, Lingling; Guo, Yongquan; Zheng, Qiaoji; Lin, Dunmin

    2015-12-01

    Lead-free multifunctional ceramics of Ba0.85Ca0.15Ti0.9Zr0.1O3-x mol% Dy have been prepared by an ordinary sintering method and the effects of Dy2O3 doping on structure, piezoelectric, ferroelectric and photoluminescent properties of the ceramics have been studied. The ceramics possess a single phase perovskite structure. The grain growth of the ceramics is prohibited and the ferroelectric-paraelectric phase transition at TC becomes more diffusive after the addition of Dy2O3. Dy2O3 doping improves the piezoelectricity of the ceramics and the optimal piezoelectric properties d33 = 335 pC/N is obtained at x = 0.5. The addition of 2 mol% Dy enhances the photoluminescent properties of the ceramics and strong emissions at ˜ 478 nm and ˜ 575 nm are observed. Our study shows that the ceramics with low Dy2O3 levels exhibit simultaneously the strong piezoelectricity, ferroelectricity and photoluminescence and may have a potential application in mechano-electro-optic integration and coupling device.

  1. Rayleigh Behavior in the Lead Free Piezoelectric Lix(Na0.5K0.5)1-xNbO3 Ceramic

    NASA Astrophysics Data System (ADS)

    Kobayashi, Keisuke; Hatano, Keiichi; Mizuno, Youichi; Randall, Clive A.

    2012-03-01

    The nonlinear behavior of piezoelectric response in Lix(Na0.5K0.5)1-xNbO3 ceramics with x=0.00-0.08 was investigated by Rayleigh analysis. These ceramics exhibited a linear dependence of the piezoelectric coefficient, d33, with the applied electric field. This data was then analyzed in accordance to the Rayleigh model for poled ceramic materials. The intrinsic contribution was found to be maximized at x=0.06, where this system has a polymorphic phase boundary at room temperature. The extrinsic contribution, which is the origin of the nonlinearity of piezoelectric response, had a maximum value at x=0.03-0.04 and is considered to be strongly affected by the crystal symmetry and domain structures.

  2. Lead-free ceramics for pyroelectric applications

    NASA Astrophysics Data System (ADS)

    Lau, S. T.; Cheng, C. H.; Choy, S. H.; Lin, D. M.; Kwok, K. W.; Chan, H. L. W.

    2008-05-01

    The use of lead-free materials has recently become a very important issue in environmental protection of the earth. Two groups of lead-free ceramics, (K0.5,Na0.5)NbO3 based (KNN) and Bi1-y(NaxK1-x)yTiO3 based (BNKT), were studied for their thermal, dielectric, and pyroelectric properties as candidates for pyroelectric sensor applications. The BNKT-based ceramic, [Bi0.5(Na0.94K0.05Li0.016)0.5]0.95Ba0.05TiO3 (BNKLBT), shows excellent pyroelectric properties when compared with KNN-based ceramic and lead zirconate titanate. Its properties were measured as follows: pyroelectric coefficient p =360μC/m2K, pyroelectric figure of merit of current, voltage, and detectivity Fi=221pm/V, Fv=0.030m2/C, and Fd=14.8μPa-1/2. With these outstanding pyroelectric properties, the BNKLBT ceramic can be a promising material for pyroelectric sensor applications. The BNKLBT ceramic with different thicknesses (i.e., 0.3, 0.5, and 0.7mm) have been used as the sensing element for fabricating infrared detectors. The current responsivity of the sensors was evaluated as functions of frequency.

  3. Dual-enhancement of ferro-/piezoelectric and photoluminescent performance in Pr3+ doped (K0.5Na0.5)NbO3 lead-free ceramics

    NASA Astrophysics Data System (ADS)

    Wei, Yongbin; Wu, Zheng; Jia, Yanmin; Wu, Jiang; Shen, Yichao; Luo, Haosu

    2014-07-01

    A mutual enhancement action between the ferro-/piezoelectric polarization and the photoluminescent performance of rare earth Pr3+ doped (K0.5Na0.5)NbO3 (KNN) lead-free ceramics is reported. After Pr3+ doping, the KNN ceramics exhibit the maximum enhancement of ˜1.2 times in the ferroelectric remanent polarization strength and ˜1.25 times in the piezoelectric coefficient d33, respectively. Furthermore, after undergoing a ferro-/piezoelectric polarization treatment, the maximum enhancement of ˜1.3 times in photoluminescence (PL) was observed in the poled 0.3% Pr3+ doped sample. After the trivalent Pr3+ unequivalently substituting the univalent (K0.5Na0.5)+, A-sites ionic vacancies will occur to maintain charge neutrality, which may reduce the inner stress and ease the domain wall motions, yielding to the enhancement in ferro-/piezoelectric performance. The polarization-induced enhancement in PL is attributed to the decrease of crystal symmetry abound the Pr3+ ions after polarization. The dual-enhancement of the ferro-/piezoelectric and photoluminescent performance makes the Pr3+ doped KNN ceramic hopeful for piezoelectric/luminescent multifunctional devices.

  4. Dual-enhancement of ferro-/piezoelectric and photoluminescent performance in Pr{sup 3+} doped (K{sub 0.5}Na{sub 0.5})NbO{sub 3} lead-free ceramics

    SciTech Connect

    Wei, Yongbin; Jia, Yanmin E-mail: ymjia@zjnu.edu.cn; Wu, Jiang; Shen, Yichao; Wu, Zheng E-mail: ymjia@zjnu.edu.cn; Luo, Haosu

    2014-07-28

    A mutual enhancement action between the ferro-/piezoelectric polarization and the photoluminescent performance of rare earth Pr{sup 3+} doped (K{sub 0.5}Na{sub 0.5})NbO{sub 3} (KNN) lead-free ceramics is reported. After Pr{sup 3+} doping, the KNN ceramics exhibit the maximum enhancement of ∼1.2 times in the ferroelectric remanent polarization strength and ∼1.25 times in the piezoelectric coefficient d{sub 33}, respectively. Furthermore, after undergoing a ferro-/piezoelectric polarization treatment, the maximum enhancement of ∼1.3 times in photoluminescence (PL) was observed in the poled 0.3% Pr{sup 3+} doped sample. After the trivalent Pr{sup 3+} unequivalently substituting the univalent (K{sub 0.5}Na{sub 0.5}){sup +}, A-sites ionic vacancies will occur to maintain charge neutrality, which may reduce the inner stress and ease the domain wall motions, yielding to the enhancement in ferro-/piezoelectric performance. The polarization-induced enhancement in PL is attributed to the decrease of crystal symmetry abound the Pr{sup 3+} ions after polarization. The dual-enhancement of the ferro-/piezoelectric and photoluminescent performance makes the Pr{sup 3+} doped KNN ceramic hopeful for piezoelectric/luminescent multifunctional devices.

  5. Preparation and characterization of Mn-doped Li0.06(Na0.5K0.5)0.94NbO3 lead-free piezoelectric ceramics with surface sol-gel coatings

    NASA Astrophysics Data System (ADS)

    Yoo, Ae Ri; Lee, Seong Eui; Lee, Hee Chul

    2014-08-01

    This study investigated the effects of Mn doping and sol-gel surface coating on the structural and the electrical properties of lead-free Li0.06(Na0.5K0.5)0.94NbO3(LNKN) ceramics in disc form for use as eco-friendly piezoelectric devices. The 1-mol% Mn-doped LNKN ceramic showed a relatively high piezoelectric constant owing to its high density in the case of its being annealed at a temperature of 1010 °C. A Mn-doped LNKN sol-gel solution with the same composition as that of the ceramics was spin-coated and sintered on both sides of the ceramic surfaces to acquire improved electrical properties. The sol-gel surface coating could play a decisive role in filling the pores, resulting in flat and stable interfaces between the electrodes and the piezoelectric elements. As a result, the highest piezoelectric constant, d33, of 173 pC/N could be obtained for the Mn-doped LNKN ceramics with 420-nm-thick sol-gel surface coatings.

  6. Microstructure and Electrical Properties of K0.5Na0.5NbO3-LiSbO3-BiFeO3- x %molZnO Lead-Free Piezoelectric Ceramics

    NASA Astrophysics Data System (ADS)

    Zhao, Xiayan; Wang, Hua; Xu, Jiwen; Yuan, Changlai; Zhai, Xia; Cui, Yerang

    2014-02-01

    Lead-free piezoelectric ceramics {0.996[(0.95(K0.5Na0.5)NbO3-0.05LiSbO3]-0.004BiFeO3}- xmol%ZnO were prepared through a conventional ceramics sintering technique. The effect of ZnO content on structure, microstructure, and piezoelectric properties of KNN-LS-BF ceramics was investigated. The results reveal that ZnO as a sintering aid is very effective in promoting sinterability and electrical properties of the ceramics sintered at a low temperature of 1,020 °C. The ceramics show a single-perovskite structure with predominant tetragonal phase, and coexistence of orthorhombic and tetragonal phases is observed for x = 2.5-3.0. The addition of ZnO causes abnormal grain growth. A dense microstructure is also obtained at x = 2.0 because the relative density reaches up to 94.6 %. The morphotropic phase boundary and dense microstructure lead to significant enhancement of the piezoelectric properties. The ceramic with x = 1.5 exhibits optimum electrical properties as follows: d 33 = 280 pC/N, k p = 46 %, Q m = 40.8, P r = 25 μC/cm2, E c = 1.2 kV/mm, and T c = 340 °C.

  7. Structure and electrical properties of (Bi1/2Na1/2)0.94-x(Li1/2Ce1/2)xBa0.06TiO3 lead-free piezoelectric ceramics

    NASA Astrophysics Data System (ADS)

    Cheng, Renfei; Yang, Zhenjie; Xu, Zhijun; Chu, Ruiqing; Hao, Jigong; Du, Juan; Li, Guorong

    2015-06-01

    Lead-free piezoelectric ceramics BNT-BT6-LCx has been successfully synthesized by the conventional solid-state reaction method. All BNT-BT6-LCx ceramics form the pure perovskite phase structure, and no obvious change in the crystal structure is observed with the addition of (Li1/2Ce1/2). Transition temperature Tm is found to be no obvious change and Td decreases continuously with x. Composition with x=0.010 has shown the optimum ferroelectric and piezoelectric properties with low value of Ec, which are as follows: Pr=32.65 μC/cm2, Ec=41 kV/cm and d33=163 pC/N.

  8. Properties of Miniature Cantilever-Type Ultrasonic Motor Using Lead-Free Array-Type Multilayer Piezoelectric Ceramics of (Sr,Ca)2NaNb5O15 under High Input Power

    NASA Astrophysics Data System (ADS)

    Doshida, Yutaka; Shimizu, Hiroyuki; Mizuno, Youich; Tamura, Hideki

    2012-07-01

    The properties of miniature cantilever-type ultrasonic motors using lead-free array-type multilayer piezoelectric ceramics of (Sr,Ca)2NaNb5O15 (SCNN) developed using the design rule were investigated under high input power by comparison with the high-power properties of SCNN ceramics. The frequency dependence of the revolution speed reflected the nonlinear behavior of SCNN ceramics with the hard-spring effect and showed a mirror-reversed image relative to that of the motor of Pb(Zr,Ti)O3 (PZT) ceramics. The output power increased linearly with increasing input power up to 110 mW without heat generation, and the driving properties were almost the same as the expectations under low input power. The output power density characteristics of the motors were high in comparison with those of the commercialized motors of PZT ceramics. It appeared that the motors have a high potential as an environmental friendly piezoelectric device with excellent properties, reflecting the high-power properties of SCNN ceramics.

  9. Dielectric, Ferroelectric, and Piezoelectric Properties of Mn-Doped K0.5Na0.5NbO3 Lead-Free Ceramics

    NASA Astrophysics Data System (ADS)

    Lopez-Juarez, Rigoberto; Gomez-Vidales, Virginia; Cruz, M. P.; Villafuerte-Castrejon, M. E.

    2015-08-01

    In this work, study of manganese-doped potassium-sodium niobate ceramics was performed. It was found that, with increasing Mn2+ content from 1 mol.% to 1.5 mol.%, the Q m changed from 60 to near 500 with no appreciable detriment in piezoelectric properties. These properties first increased with 0.5 mol.%, and remained almost constant with 1 mol.% of manganese. Maximum values for d 33, d 31, and k p were 120 pC N-1, 33 pC N-1, and 36%, respectively. Thus, manganese-doped K0.5Na0.5NbO3 ceramics represent an option for high-power applications.

  10. Piezoelectric and ferroelectric properties of lead-free LiNbO3-modified 0.97(Bi0.5Na0.5TiO3)-0.03BaZrO3 ceramics

    NASA Astrophysics Data System (ADS)

    Rahman, Jamil Ur; Hussain, Ali; Maqbool, Adnan; Malik, Rizwan Ahmed; Song, Tae Kwon; Kim, Myong Ho; Lee, Soonil; Kim, Won Jeong

    2015-02-01

    Lead-free piezoelectric ceramics (1- x) [(0.97Bi0.5Na0.5TiO3)]-0.03BaZrO3- xLiNbO3 (BNT-BZ3- xLN) with x = (0-0.07) were synthesized using the conventional solid-state reaction method, and their crystal structure, microstructure, and dielectric, ferroelectric and piezoelectric properties were investigated as a function of the LN content. The X-ray diffraction patterns revealed the formation of a single-phase perovskite structure for all the LN-modified BNT-BZ ceramics in this study. The results indicate that the LN substitution into BNT-BZ3 induces a transition from a ferroelectric to a diffuse and/or relaxor state accompanying a field-induced strain of 0.20% for x = 0.05 at an applied field of 6 kV/mm. The corresponding dynamic piezoelectric coefficient for this composition was ( S max/ E max = 333 pm/V). A significant reduction of the coercive field ( E c) and enhancement of the piezoelectric constant ( d 33) from 98 pC/N for x = 0 to 117 pC/N x = 0.01 was observed.

  11. A lead-free piezoelectric transformer in radial vibration modes.

    PubMed

    Guo, Mingsen; Lin, D M; Lam, K H; Wang, S; Chan, Helen L W; Zhao, X Z

    2007-03-01

    In this study, a disk-shaped piezoelectric transformer was fabricated using lead-free (K,Na)NbO(3)-based ceramics with high mechanical quality factor. The transformer can operate in the fundamental or the third radial vibration mode. The transformer is poled along the thickness direction. The top surface is covered by ring/dot silver electrodes separated by an annular gap which serve as the input and output parts of the transformer, respectively. The bottom surface, fully covered with a silver electrode, is grounded as a common electrode. The dimensions of the top ring/dot electrodes are designed such that the third radial vibration mode can be strongly excited. The electrical properties of the transformer with diameter of 34.2 mm and thickness of 1.9 mm were measured. For a temperature rise of 35 degrees C, the transformer has a maximum output power of 12 W. With the matching load, its maximum efficiency is >95%, and maximum voltage gains are 6.5 and 3.9 for the fundamental and the third radial vibration modes, respectively. It has potential to be used in power supply units and other electronic circuits. PMID:17411212

  12. First-principles calculation of the effects of Li-doping on the structure and piezoelectricity of (K0.5Na0.5)NbO3 lead-free ceramics.

    PubMed

    Yang, D; Wei, L L; Chao, X L; Yang, Z P; Zhou, X Y

    2016-03-01

    The crystal structures of the lead-free piezoelectric ceramics (K0.5Na0.5)NbO3 and (K0.5Na0.5)0.94Li0.06NbO3 prepared by a solid-state method were investigated using first-principles calculations. The calculated values of piezoelectricity were in good agreement with the experimental data. We found that the primary contribution to piezoelectricity in this material comes from the hybridization of the O 2p and Nb 4d orbitals, which causes a change in the Nb-O bond length and the distortion of the Nb-O octahedral structure. Analysis of the band structure and the total density of states revealed that Li-doped (K0.5Na0.5)NbO3 enhances hybridization of the O 2p and Nb 4d orbitals. This hybridization enhancement further reduces the Nb-O1 bond length and enhances the distortion of the Nb-O octahedron along the [001] direction, which may be the main reason for the improvement of the piezoelectric properties. In addition, the piezoelectric coefficients are calculated here, which show the same trend as the experimental results. PMID:26906892

  13. Structure, ferroelectric and piezoelectric properties of (Bi0.98- x La0.02Na1- x )0.5Ba x TiO3 lead-free ceramics

    NASA Astrophysics Data System (ADS)

    Lin, Dunmin; Kwok, K. W.

    2009-10-01

    Lead-free (Bi0.98- x La0.02Na1- x )0.5Ba x TiO3 ceramics have been prepared by an ordinary sintering technique and their structure, ferroelectric and piezoelectric properties have been studied. The results of X-ray diffraction show that La2+ and Ba2+ diffuse into the Bi0.5Na0.5TiO3 lattices to form a new solid solution with a pure perovskite structure, and a morphotropic phase boundary (MPB) exists at 0.04< x<0.10. Compared with pure Bi0.5Na0.5TiO3 ceramics, the (Bi0.98- x La0.02Na1- x )0.5Ba x TiO3 ceramics possess much smaller coercive field E c and larger remanent polarization P r. Because of the low E c (3.38 kV/mm), large P r (46.2 μC/cm2) and the formation of the MPB of rhombohedral and tetragonal phases, the piezoelectric properties of the ceramics are significantly enhanced at x=0.06: d 33=181 pC/N and k p=36.3%. The depolarization temperature T d reaches a minimum value near the MPB. The ceramics exhibit relaxor characteristic, which is probably a result from the cation disordering in the 12-fold coordination sites. The temperature dependences of the ferroelectric and dielectric properties suggest that the ceramics may contain both polar and non-polar regions at the temperatures above T d.

  14. Tonpilz Underwater Acoustic Transducer Integrating Lead-free Piezoelectric Material

    NASA Astrophysics Data System (ADS)

    Rouffaud, Rémi; Granger, Christian; Hladky-Hennion, Anne-Christine; Thi, Mai Pham; Levassort, Franck

    A Tonpilz transducer based on lead-free piezoelectric material was fabricated, modeled and characterized. The stack is composed of two rings of doped BaTiO3. This composition was initially chosen due to good electromechanical performance (kt at 40%) and high mechanical quality factor (Qm over 500). Comparison of the displacement at the center of the head mass was performed with a PZT-based Tonpilz with the same design for a center frequency at 22 kHz.

  15. Magnetoelectric effect in lead-free BNKLBT ceramic/terfenol-D continue fiber composite laminates

    NASA Astrophysics Data System (ADS)

    Lo, C. Y.; Choy, S. H.; Or, S. W.; Chan, H. L. W.

    2010-05-01

    A magnetostrictive-piezoelectric laminated composite has been developed by sandwiching a lead-free BNKLBT ceramic plate polarized in the thickness direction between two terfenol-D continuous fiber composite plates. This lead-free magnetoelectric (ME) laminated composite has a large ME voltage sensitivity of 2.5 V/Oe at the resonance frequency of 130.9 kHz under a low magnetic bias field (HBias) of 0.6 kOe. This work shows the potential of BNKLBT lead-free ceramics in ME sensing application.

  16. Lead-free piezoelectric materials and ultrasonic transducers for medical imaging

    NASA Astrophysics Data System (ADS)

    Taghaddos, Elaheh; Hejazi, Mehdi; Safari, Ahmad

    2015-06-01

    Piezoelectric materials have been vastly used in ultrasonic transducers for medical imaging. In this paper, firstly, the most promising lead-free compositions with perovskite structure for medical imaging applications have been reviewed. The electromechanical properties of various lead-free ceramics, composites, and single crystals based on barium titanate, bismuth sodium titanate, potassium sodium niobate, and lithium niobate are presented. Then, fundamental principles and design considerations of ultrasonic transducers are briefly described. Finally, recent developments in lead-free ultrasonic probes are discussed and their acoustic performance is compared to lead-based transducers. Focused transducers with different beam focusing methods such as lens focusing and mechanical shaping are explained. Additionally, acoustic characteristics of lead-free probes including the pulse-echo results as well as their imaging capabilities for various applications such as phantom imaging, in vitro intravascular ultrasound imaging of swine aorta, and in vivo or ex vivo imaging of human eyes and skin are reviewed.

  17. Lead-Free Intravascular Ultrasound Transducer Using BZT-50BCT Ceramics

    PubMed Central

    Yan, Xingwei; Lam, Kwok Ho; Li, Xiang; Chen, Ruimin; Ren, Wei; Ren, Xiaobing; Zhou, Qifa; Shung, K. Kirk

    2013-01-01

    This paper reports the fabrication and evaluation of a high-frequency ultrasonic transducer based on a new lead-free piezoelectric material for intravascular imaging application. Lead-free 0.5Ba(Zr0.2Ti0.8)O3−0.5(Ba0.7Ca0.3)TiO3 (BZT-50BCT) ceramic with a high dielectric constant (~2800) was employed to develop a high-frequency (~30 MHz) needle-type ultrasonic transducer. With superior piezoelectric performance (piezoelectric coefficient d33 ~ 600 pC/N), the lead-free transducer was found to exhibit a −6-dB bandwidth of 53% with an insertion loss of 18.7 dB. In vitro intravascular ultrasound (IVUS) imaging of a human cadaver coronary artery was performed to demonstrate the potential of the lead-free transducer for biomedical imaging applications. This is the first time that a lead-free transducer has been used for IVUS imaging application. The experimental results suggest that the BZT-50BCT ceramic is a promising lead-free piezoelectric material for high-frequency intravascular imaging applications. PMID:25004492

  18. Lead-free intravascular ultrasound transducer using BZT-50BCT ceramics.

    PubMed

    Yan, Xingwei; Lam, Kwok Ho; Li, Xiang; Chen, Ruimin; Ren, Wei; Ren, Xiaobing; Zhou, Qifa; Shung, K Kirk

    2013-06-01

    This paper reports the fabrication and evaluation of a high-frequency ultrasonic transducer based on a new lead-free piezoelectric material for intravascular imaging application. Lead-free 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO4(BZT-50BCT) ceramic with a high dielectric constant (~2800) was employed to develop a high-frequency (~30 MHz) needle-type ultrasonic transducer. With superior piezoelectric performance (piezoelectric coefficient d33 ~ 600 pC/N), the lead-free transducer was found to exhibit a -6-dB bandwidth of 53% with an insertion loss of 18.7 dB. In vitro intravascular ultrasound (IVUS) imaging of a human cadaver coronary artery was performed to demonstrate the potential of the lead-free transducer for biomedical imaging applications. This is the first time that a lead-free transducer has been used for IVUS imaging application. The experimental results suggest that the BZT-50BCT ceramic is a promising lead-free piezoelectric material for high-frequency intravascular imaging applications. PMID:25004492

  19. Diffuse phase transition and electrical properties of lead-free piezoelectric (LixNa1-x)NbO3 (0.04 ≤ x ≤ 0.20) ceramics near morphotropic phase boundary

    NASA Astrophysics Data System (ADS)

    Mitra, S.; Kulkarni, A. R.; Prakash, Om

    2013-08-01

    Temperature-dependent dielectric permittivity of lead-free (LixNa1-x)NbO3 for nominal x = 0.04-0.20, prepared by solid state reaction followed by sintering, was studied to resolve often debated issue pertaining to exactness of morphotropic phase boundary (MPB) location besides structural aspects and phase stability in the system near MPB. Interestingly, a diffuse phase transition has been observed in the dielectric permittivity peak arising from the disorder induced in A-site and structural frustration in the perovskite cell due to Li substitution. A partial phase diagram has been proposed based on temperature-dependent dielectric permittivity studies. The room temperature piezoelectric and ferroelectric properties were investigated and the ceramics with x = 0.12 showed relatively good electrical properties (d33 = 28 pC/N, kp = 13.8%, Qm = 440, Pr = 12.5 μC/cm2, Ec = 43.2 kV/cm, and Tm = 340 °C). These parameter values make this material suitable for piezoelectric resonator and filter applications. Moreover, a high dielectric permittivity (ɛ'r = 2703) with broad diffuse peak near transition temperature, and low dielectric loss (<4%) over a wide temperature range (50-250 °C) found in this material may also have a potential application in high-temperature multilayer capacitors in automotive and aerospace related industries.

  20. Lead-free piezoelectrics based on potassium-sodium niobate with giant d(33).

    PubMed

    Zhang, Binyu; Wu, Jiagang; Cheng, Xiaojing; Wang, Xiaopeng; Xiao, Dingquan; Zhu, Jianguo; Wang, Xiangjian; Lou, Xiaojie

    2013-08-28

    High-performance lead-free piezoelectrics (d33 > 400 pC/N) based on 0.96(K0.5Na0.5)0.95Li0.05Nb1-xSbxO3-0.04BaZrO3 with the rhombohedral-tetragonal (R-T) phase boundary have been designed and prepared. The R-T phase boundary lies the composition range of 0.04 ? x ? 0.07, and the dielectric and piezoelectric properties of the ceramics with the compositions near the phase boundary are significantly enhanced. In addition, the ceramic with x = 0.07 has a giant d33 of ~425 pC/N, which is comparable to that (~416 pC/N) of textured KNN-based ceramics (Saito, Y.; Takao, H.; Tani, T.; Nonoyama, T.; Takatori, K.; Homma, T.; Nagaya, T.; Nakamura, M. Nature 2004, 432, 84). The underlying physical mechanisms for enhanced piezoelectric properties are addressed. We believe that the material system is the most promising lead-free piezoelectric candidates for the practical applications. PMID:23937157

  1. Raman and Dielectric Studies on Lead free (K0.5Na0.5) NbO3 Piezoelectric Ceramics

    NASA Astrophysics Data System (ADS)

    Mahesh, P.; Pamu, D.

    2015-02-01

    The present study demonstrates the preparation of (K0.5Na0.5)NbO3 (KNN) ceramics at low temperatures by using mechanochemical synthesis process. The effect of calcination temperature on structure, and dielectric properties of KNN ceramics have been studied systematically. It is found that both the dielectric constant and tanδ of KNN ceramics as a function of temperature exhibited two sharp phase transitions indicating orthorhombic to tetragonal (184°C) and ferroelectric tetragonal to paraelectric cubic phases (385°C). It was observed that the ceramics calcined at 700°C and sintered at 1000°C shows the high Curie temperature, high dielectric permittivity and low dielectric loss. Further with increase in calcination temperature, the ferroelectric tetragonal to paraelectric cubic phase shifted to lower temperatures. Raman spectra of KNN ceramics were obtained and the three characteristic Raman peaks in the spectra of KNN are related to the internal vibrations of the NbO6 octahedron. The effect of processing parameters on dielectric properties and phase transitions studied systematically.

  2. Dielectric and piezoelectric properties of lead-free 0.5Ba(Zr0.2 Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 piezoelectric ceramics with glass additive.

    PubMed

    Im, In-Ho; Chung, Kwang-Hyun

    2014-12-01

    We have investigated the dielectric and piezoelectric properties of lead-free 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 ceramics with BaO-CaO-SiO2 glass additive as a function of sintering temperatures. With adding BaO-CaO-SiO2 glass additive, diffusivity of lead-free 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 ceramics was increased. The dispersion constant ? of BZT-BCT ceramics with BaO-CaO-SiO2 glass was changed from 1.9683 to 1.7673 by decreasing sintering temperature ranging from 1450 degrees C to 1350 degrees C, while 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 ceramics at sintered 1450 degrees C showed ? = 1.5055. The piezoelectric properties such as electromechanical coupling factor (k(p)) and piezoelectric constant (d33) of lead-free 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 ceramics with BaO-CaO-SiO2 glass additive sintered at 1400 degrees C showed similar values compared with 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 ceramics without BaO-CaO-SiO2 glass additive sintered at 1450 degrees C. The addition of BaO-CaO-SiO2 glass additive can be of help to decrease sintering temperature of lead-free 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 ceramics. PMID:25970982

  3. Defect Engineering of Lead-Free Piezoelectrics with High Piezoelectric Properties and Temperature-Stability.

    PubMed

    Feng, Yu; Li, Wei-Li; Xu, Dan; Qiao, Yu-Long; Yu, Yang; Zhao, Yu; Fei, Wei-Dong

    2016-04-13

    The high piezoelectricity of ABO3-type lead-free piezoelectric materials can be achieved with the help of either morphotropic phase boundary (MPB) or polymorphic phase transition (PPT). Here, we propose a new defect engineering route to the excellent piezoelectric properties, in which doped smaller acceptor and donor ions substituting bivalent A-sites are utilized to bring local lattice distortion and lower symmetry. A concrete paradigm is presented, (Li-Al) codoped BaTiO3 perovskite, that exhibits a largely thermo-stable piezoelectric constant (>300 pC/N) and huge mechanical quality factor (>2000). A systematic analysis including theoretical analysis and simulation results indicates that the Li(+) and Al(3+) ions are inclined to occupy the neighboring A-sites in the lattice and constitute a defect dipole (ionic pairs). The defect dipoles possess a kind of dipole moment which tends to align directionally after thermo-electric treatment. A mechanism related to the defect symmetry principle, phase transition, and defect migration is proposed to explain the outstanding piezoelectric properties. The present study opens a new development window for excellent piezoelectricity and provides a promising route to the potential utilization of lead-free piezoelectrics in high power applications. PMID:27010869

  4. Phase structure and piezoelectric properties of (1-x)K0.48Na0.52Nb0.95Sb0.05O3-x(Bi0.5Na0.5)0.9(Li0.5Ce0.5)0.1ZrO3 lead-free piezoelectric ceramics

    NASA Astrophysics Data System (ADS)

    Xing, Jie; Tan, Zhi; Jiang, Laiming; Chen, Qiang; Wu, Jiagang; Zhang, Wen; Xiao, Dingquan; Zhu, Jianguo

    2016-01-01

    (1-x)K0.48Na0.52Nb0.95Sb0.05O3-x(Bi0.5Na0.5)0.9(Li0.5Ce0.5)0.1ZrO3 [(1-x)KNNS-xBNLCZ] lead-free piezoceramics were prepared by the conventional solid state sintering method. The effects of BNLCZ contents on their phase structure, microstructure, and piezoelectric properties were investigated. All the samples show a pure perovskite structure, and no secondary phases were formed in the detected range. The rhombohedral and tetragonal phases of (1-x)KNNS-xBNLCZ coexist in the composition range of 0.0325 ? x ? 0.0425 at room temperature. A remarkably strong piezoelectricity was obtained by the addition of appropriate BNLCZ contents. The excellent piezoelectric properties of the ceramics with x = 0.04 were obtained: d33 485 pC/N, kp 48%, and TC 227 C. All the results show that the introduction of (Bi0.5Na0.5)0.9(Li0.5Ce0.5)0.1ZrO3 is a very effective way to form the rhombohedral and tetragonal phase coexistence of potassium-sodium niobate-based ceramics, which can improve its piezoelectric properties.

  5. Sintering, microstructure and electrical properties of 0.4(Bi0.5K0.5)TiO3-0.6BiFeO3 lead-free piezoelectric ceramics

    NASA Astrophysics Data System (ADS)

    Fisher, John G.; Park, Ha-Young; Song, Yeo-Ok; Baek, Sun-Joong; Vu, Hung; Kim, Jee-Hoon; Kim, Young-Hun; Lee, Jong Sook

    2016-01-01

    The effect of sintering temperature on the densification, microstructure and structure of 0.4(Bi0.5K0.5)TiO3-0.6BiFeO3 lead-free piezoelectric ceramics is assessed. The 0.4(Bi0.5K0.5)TiO3-0.6BiFeO3 powders were prepared by using the mixed-oxide method and were sintered at temperatures of 1000, 1050 and 1100 °C for 1 to 5 hrs. Unlike earlier work, the sintered samples showed high densities even when sintered at 1000 °C. X-ray diffraction revealed that the sintered samples shared the same rhombohedral structure as BiFeO3. With increasing sintering temperature, the rhombohedral distortion of the unit cell decreased. In addition to the relaxor-like broad peak around 400 °C, a low-temperature dielectric peak was found at temperatures below 190 °C by employing a low-frequency sweep down to 10 mHz. The DC conductivity of the 0.4(Bi0.5K0.5)TiO3-0.6BiFeO3 sample exhibited three temperature regions with activation energy values of 0.56 eV (T > 500°C), 0.72 eV (400°C < T <200°C) and 0.81 eV (T < 190°C). The characteristic transitions in the conductivity could be related to the Néel temperature (370°C) and the conductivity anomaly observed at ca. 190°C in BiFeO3.

  6. Development of lead-free piezoelectric thin films by pulsed laser deposition

    NASA Astrophysics Data System (ADS)

    Abazari Torghabeh, Maryam

    As a high performance piezoelectric material widely used in sensors, actuators and other electronic devices, lead zirconate titanate (PZT) ceramics have been the center of attention for many years. However, the toxicity of these materials and their exposure to the environment during processing steps, such as calcination, sintering, machining as well as problems in recycling and disposal have been major concerns regarding their usage all around the globe for the past couple of decades. Consequently, utilizing lead-based materials for many commercial applications have been recently restricted in Europe and Asia and measures are being taken in United States as well. Therefore, there is an urgent need for lead-free piezoelectrics whose properties are comparable to those of well-known PZT materials. Recently, the discovery of ultra-high piezoelectric activity in the ternary lead-free KNaNbO3-LiTaO 3-LiSbO3 (KNN-LT-LS) and (Bi,Na)TiO3-(Bi,K)TiO 3-BaTiO3 (BNT-BKT-BT) systems have given hope for alternatives to PZT. Furthermore, the demand for new generation of environment-friendly functional devices, utilizing piezoelectric materials, inspired a new surge in lead-free piezoelectric thin film research. In this study, an attempt has been made to explore the development of lead-free piezoelectric thin films by Pulsed Laser Deposition (PLD) on SrTiO 3 substrate. While the growth and development process of KNN-LT-LS thin films was the primary goal of this thesis, a preliminary effort was also made to fabricate and characterize BNT-BKT-BT thin films. In a comprehensive and systematic process optimization study in conjunction with X-ray diffractometry, the phase evolution, stoichiometry, and growth orientation of the films are monitored as a function of deposition conditions including temperature and ambient oxygen partial pressure. Processing parameters such as substrate temperature and pressure are shown to be highly dominant in determining the phase and composition of the films. Oxygen partial pressure has shown to control the chemical composition of the films through solid-gaseous phase equilibrium and substrate temperature has mostly influenced the growth mode and microstructure. Findings of this study has shown that 300-500 nm single-phase epitaxial KNN-LT-LS and BNT-BKT-BT thin films could indeed be obtained at a temperature of 700-750°C and 300-400 mTorr of oxygen partial pressure. Following a series of studies on effect of doping, it was revealed that addition of 1 mol% Mn to KNN-LT-LS composition resulted in a significant suppression of leakage current and enhancement of polarization saturation. A remanent polarization of 16 muC/cm 2 and coercive field of 20 kV/cm were measured for such thin film, which are comparable to those of hard PZT counterparts. Also, a high remanent polarization and coercive field of 30 muC/cm2 and 95 kV/cm were achieved in 350 nm BNT-BKT-BT thin films. Longitudinal (d33) and transverse (e31,f) piezoelectric coefficients of KNN-LT-LS thin films were found to be 55 pm/V and -4.5 C/m2 respectively, prepared at the optimized conditions, whereas 350 nm BNT-BKT-BT thin films exhibited an e31,f of -2.25 C/m2. The results of this study present the great potential of KNN-LT-LS and BNT-BKT-BT thin films for piezoelectric MEMS devices and provide a baseline for future investigations on lead-free piezoelectric thin films.

  7. New lead-free piezoelectric ceramics based on (K0.48Na0.52)(Nb0.95Ta0.05)O3-Bi0.5(Na0.7K0.2Li0.1)0.5ZrO3.

    PubMed

    Cheng, Xiaojing; Wu, Jiagang; Wang, Xiaopeng; Zhang, Binyu; Zhu, Jianguo; Xiao, Dingquan; Wang, Xiangjian; Lou, Xiaojie

    2014-03-01

    (1 - x)(K0.48Na0.52)(Nb0.95Ta0.05)O3-xBi0.5(Na0.7K0.2Li0.1)0.5ZrO3 lead-free piezoelectric ceramics with a new type of phase boundary have been designed and fabricated. This phase boundary lies in the compositional range of 0.04 ? x ? 0.05, and is formed by the coexistence of the rhombohedral, orthorhombic, and tetragonal phases. Interestingly, we found that the ferroelectric, dielectric, and piezoelectric properties of the ceramics with compositions near the phase boundary are significantly enhanced. In particular, the ceramic with x = 0.045 shows the best piezoelectric behavior of d33 ? 290 pC/N and kp ? 0.42 among all the compositions studied in this work, and it also exhibits a good thermal stability at annealing temperatures of ?270 C. All these results indicate that such a material system is a good candidate for lead-free piezoelectric applications in the future. PMID:24452129

  8. Lead-Free Piezoceramics: Revealing the Role of the Rhombohedral-Tetragonal Phase Coexistence in Enhancement of the Piezoelectric Properties.

    PubMed

    Rubio-Marcos, Fernando; López-Juárez, Rigoberto; Rojas-Hernandez, Rocio E; del Campo, Adolfo; Razo-Pérez, Neftalí; Fernandez, Jose F

    2015-10-21

    Until now, lead zirconate titanate (PZT) based ceramics are the most widely used in piezoelectric devices. However, the use of lead is being avoided due to its toxicity and environmental risks. Indeed, the attention in piezoelectric devices has been moved to lead-free ceramics, especially on (K,Na)NbO3-based materials, due to growing environmental concerns. Here we report a systematic evaluation of the effects of the compositional modifications induced by replacement of the B-sites with Sb(5+) ions in 0.96[(K0.48Na0.52)0.95Li0.05Nb1-xSbxO3]-0.04[BaZrO3] lead-free piezoceramics. We show that this compositional design is the driving force for the development of the high piezoelectric properties. So, we find that this phenomenon can be explained by the stabilization of a Rhombohedral-Tetragonal (R-T) phase boundary close to room temperature, that facilities the polarization process of the system and exhibits a significantly high piezoelectric response with a d33 value as high as ∼400 pC/N, which is comparable to part soft PZTs. As a result, we believe that the general strategy and design principles described in this study open the possibility of obtaining (K,Na)NbO3-based lead-free ceramics with enhanced properties, expanding their application range. PMID:26436199

  9. Effect of composition on electrical properties of lead-free Bi{sub 0.5}(Na{sub 0.80}K{sub 0.20}){sub 0.5}TiO{sub 3}-(Ba{sub 0.98}Nd{sub 0.02})TiO{sub 3} piezoelectric ceramics

    SciTech Connect

    Jaita, Pharatree; Watcharapasorn, Anucha; Jiansirisomboon, Sukanda

    2013-07-14

    Lead-free piezoelectric ceramics with the composition of (1-x)Bi{sub 0.5}(Na{sub 0.80}K{sub 0.20}){sub 0.5}TiO{sub 3}-x(Ba{sub 0.98}Nd{sub 0.02})TiO{sub 3} or (1-x) BNKT-xBNdT (with x = 0-0.20 mol fraction) have been synthesized by a conventional mixed-oxide method. The compositional dependence of phase structure and electrical properties of the ceramics were systemically studied. The optimum sintering temperature of all BNKT-BNdT ceramics was found to be 1125 Degree-Sign C. X-ray diffraction pattern suggested that BNdT effectively diffused into BNKT lattice during sintering to form a solid solution with a perovskite structure. Scanning electron micrographs showed a slight reduction of grain size when BNdT was added. It was found that BNKT-0.10BNdT ceramic exhibited optimum electrical properties ({epsilon}{sub r} = 1716, tan{delta} = 0.0701, T{sub c} = 327 Degree-Sign C, and d{sub 33} = 211 pC/N), suggesting that this composition has a potential to be one of a promising lead-free piezoelectric candidate for dielectric and piezoelectric applications.

  10. The ageing and de-ageing behaviour of (Ba0.85Ca0.15)(Ti0.9Zr0.1)O3 lead-free piezoelectric ceramics

    NASA Astrophysics Data System (ADS)

    Zhang, Yichi; Glaum, Julia; Ehmke, Matthias C.; Bowman, Keith J.; Blendell, John E.; Hoffman, Mark J.

    2015-09-01

    Ageing behaviour usually occurs in acceptor-doped piezoelectric materials (e.g., hard lead zirconate titanate) and exhibits the development of a pinched or shifted hysteresis loop over time. Although no pinched hysteresis loop was observed for lead-free (Ba0.85Ca0.15)(Ti0.9Zr0.1)O3 material, this study showed that the piezoelectric properties change over time in the poled state. The shift of the hysteresis loop along the electric field axis and the development of asymmetry in strain and permittivity hysteresis loop were observed during the ageing process. The origin of this ageing behaviour is proposed to be local defect dipoles and the migration of the charged defects to the grain boundaries. The reorientation of the defect dipole contributes to a fast but unstable ageing mechanism in this material while the migration of the charged defects contributes to a slow but more stable mechanism.

  11. A study of effects of sintering on the piezoelectric properties of 0.97(K0.5Na0.5)NbO3-0.03(Bi0.5Na0.5)TiO3 lead-free ceramics

    NASA Astrophysics Data System (ADS)

    Kim, Jinhwan; Koh, Jung-Hyuk

    2013-12-01

    As a candidate for a lead free-piezoelectric material, the 0.97(K0.5Na0.5)NbO3-0.03(Bi0.5Na0.5)TiO3 ceramic was prepared by using the conventional mixed-oxide method. 0.97(K0.5Na0.5)NbO3-0.03(Bi0.5Na0.5)TiO3 ceramics were investigated to determine the effect of the sintering temperature. The crystal structures of 0.97(K0.5Na0.5)NbO3-0.03(Bi0.5Na0.5)TiO3 lead-free piezoelectric ceramics were examined by varying the sintering temperatures from 1080 °C to 1160 °C and employing an X-ray diffraction analysis and scanning electron microscopy measurements. The effects of the sintering temperature on the microstructure, piezoelectric and ferroelectric properties were systematically investigated. The dielectric and the electrical properties of the 0.97(K0.5Na0.5)NbO3-0.03(Bi0.5Na0.5)TiO3 ceramics were measured at frequency from 1 kHz to 100 kHz and at various sintering temperatures. We expect optimized sintering characteristics to improve the piezoelectric and the ferroelectric properties of 0.97(K0.5Na0.5)NbO3-0.03(Bi0.5Na0.5)TiO3 ceramics.

  12. Effect of Ta substitution on the dielectric and the piezoelectric properties of lead-free (Na0.53K0.47)0.96Li0.04(Nb1- x Ta x )O3 ceramics

    NASA Astrophysics Data System (ADS)

    Kim, Jin Soo; Kim, Min Su; Ryu, Gyung Hyun; Kim, Myong Ho; Park, Tae Gone; Park, Jongkyu

    2013-12-01

    Ta-substituted (Na0.53K0.47)0.96Li0.04(Nb1- x Ta x )O3 ceramics (NKLNT, x = 0.0, 0.013, 0.015, 0.017, 0.019, 0.021) were prepared through the solid-state reaction method. The crystallized NKLNT single phases were confirmed by using X-ray diffraction. Ta-substitution affected the dielectric behaviors and the piezoelectric properties. The enhanced piezoelectric coefficient d 33 and planar electromechanical coupling coefficient k p were estimated to be 232 pC/N and 0.46, respectively. The effects of Ta substitution on the temperature dependences of the dielectric and the piezoelectric properties were investigated at temperatures around the orthorhombic-tetragonal phase-transition temperature ( T O-T ).

  13. Dielectric, ferroelectric, and piezoelectric properties of Nb-substituted Bi1/2(Na0.82K0.18)1/2TiO3 lead-free ceramics

    NASA Astrophysics Data System (ADS)

    Pham, Ky-Nam; Lee, Han Bok; Han, Hyoung-Su; Kang, Jin Kyu; Lee, Jae-Shin; Ullah, Aman; Ahn, Chang-Won; Kim, Ill Won

    2012-01-01

    The effects of niobium substitution on the crystal structure and on the ferroelectric and piezoelectric properties of Bi1/2(Na0.82K0.18)1/2(Ti)O3 (BNKT) ceramics have been investigated. X-ray diffraction analyses revealed that Nb-substitution induced a phase transition from the coexistence of rhombohedral-tetragonal symmetry to pseudocubic symmetry. Accordingly, the electric-fieldinduced polarization and strain hysteresis loops indicated that Nb substitution significantly disrupted the ferroelectric order of BNKT ceramics, leading to degradations in the remnant polarization, coercive field, and piezoelectric coefficient d 33. However, the destabilization of the ferroelectric order was accompanied by a significant enhancement in the electric-field-induced strain (EFIS), which peaked at x = 0.03 with a value of 0.47%. The abnormal enhancement in the EFIS could be attributed to a phase transition from a non-polar to a polar phase under an applied electric field.

  14. Dielectric and piezoelectric properties of lead-free Ba0.85Ca0.15Ti0.9-xZr0.1CuxO3 ceramics synthesized by a hydrothermal method

    NASA Astrophysics Data System (ADS)

    Hunpratub, Sitchai; Phokha, Sumalin; Maensiri, Santi; Chindaprasirt, Prinya

    2016-04-01

    Ba0.85Ca0.15Ti0.9Zr0.1-xCuxO3 (BCTZC) nanopowders were synthesized using a hydrothermal method after which they were pressed into discs and sintered in air at 1300 °C for 3 h to form ceramic samples. The phase and microstructure of the powder and ceramic samples were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The XRD results indicated that the ceramic samples exhibited a tetragonal structure and that CuO, BaZrO3 or CaTiO3 impurity phases, which had been present in the powder samples, were not observed. The average grain sizes in the ceramic samples were found to be 17.0, 16.1, 20.0, 18.1 and 19.6 μm for Cu mole fractions x of 0.002, 0.004, 0.006, 0.008 and 0.01, respectively. The dielectric constants, ferroelectric hysteresis loops and piezoelectric charge coefficients of the BCZTC ceramic samples were also investigated. Optimum values for the relative dielectric constant (ɛ‧), tan δ and piezoelectric charge coefficient (d33) of the samples were 3830, 0.03 and 306 pC/N, respectively, in the Cu mole fraction samples with x = 0.002.

  15. Bright reddish-orange emission and good piezoelectric properties of Sm{sub 2}O{sub 3}-modified (K{sub 0.5}Na{sub 0.5})NbO{sub 3}-based lead-free piezoelectric ceramics

    SciTech Connect

    Hao, Jigong; Xu, Zhijun Chu, Ruiqing; Li, Wei; Du, Juan

    2015-05-21

    Reddish orange-emitting 0.948(K{sub 0.5}Na{sub 0.5})NbO{sub 3}-0.052LiSbO{sub 3}-xmol%Sm{sub 2}O{sub 3} (KNN-5.2LS-xSm{sub 2}O{sub 3}) lead-free piezoelectric ceramics with good piezoelectric properties were fabricated in this study, and the photoluminescence and electrical properties of the ceramics were systematically studied. Results showed that Sm{sub 2}O{sub 3} substitution into KNN-5.2LS induces a phase transition from the coexistence of orthorhombic and tetragonal phases to a pseudocubic phase and shifts the polymorphic phase transition (PPT) to below room temperature. The temperature stability and fatigue resistance of the modified ceramics were significantly improved by Sm{sub 2}O{sub 3} substitution. The KNN-5.2LS ceramic with 0.4 mol. % Sm{sub 2}O{sub 3} exhibited temperature-independent properties (25–150 °C), fatigue-free behavior (up to 10{sup 6} cycles), and good piezoelectric properties (d{sub 33}{sup * }= 230 pm/V, d{sub 33} = 176 pC/N, k{sub p} = 35%). Studies on the photoluminescence properties of the samples showed strong reddish-orange emission upon blue light excitation; these emission intensities were strongly dependent on the doping concentration and sintering temperature. The 0.4 mol. % Sm{sub 2}O{sub 3}-modified sample exhibited temperature responses over a wide temperature range of 10–443 K. The maximum sensing sensitivity of the sample was 7.5 × 10{sup −4} K at 293 K, at which point PPT occurred. A relatively long decay lifetime τ of 1.27–1.40 ms and a large quantum yield η of 0.17–0.19 were obtained from the Sm-modified samples. These results suggest that the KNN-5.2LS-xSm{sub 2}O{sub 3} system presents multifunctional properties and significant technological potential in novel multifunctional devices.

  16. Structural And Electrical Analysis Of Lead Free BZT-xBCT Ceramics

    SciTech Connect

    Bhardwaj, Chandan; Kumar, Ashvani; Kaur, Davinder

    2010-12-01

    A comparative study of structural and electric properties of a recently discovered lead free electroceramic, Ba(Zr{sub 0.2}Ti{sub 0.8})O{sub 3}-x(Ba{sub 0.7}Ca{sub 0.3})TiO{sub 3} or BZT-xBCT, was conducted in the entire range from x = 0 to x = 1. This novel ceramic composite is being seen as a genuine understudy for commercially one of the most widely used piezoelectric ceramic, PZT, which is facing worldwide criticism due to its lead toxicity. The new system can be very extensively used like PZT in transduction applications as sensor, actuator and ultrasonic devices apart from numerous other utilities. The XRD, SEM and Ferroelectric studies establish the structural transition and different phases as function of Zr /Ti and Ba /Ca ratios.

  17. Structure, electrical properties and temperature characteristics of Bi0.5Na0.5TiO3-Bi0.5K0.5TiO3-Bi0.5Li0.5TiO3 lead-free piezoelectric ceramics

    NASA Astrophysics Data System (ADS)

    Lin, Dunmin; Zheng, Qiaoji; Xu, Chenggang; Kwok, K. W.

    2008-11-01

    (1- x- y)Bi0.5Na0.5TiO3- xBi0.5K0.5TiO3- yBi0.5Li0.5TiO3 lead-free piezoelectric ceramics have been prepared by an ordinary sintering technique, and their structure, electrical properties, and temperature characteristics have been studied systematically. The ceramics can be well-sintered at 1050-1150 °C. The increase in K+ concentration decreases the grain-growth rate and promotes the formation of grains with a cubic shape, while the addition of Li+ decreases greatly the sintering temperature and assists in the densification of BNT-based ceramics. The results of XRD diffraction show that K+ and Li+ diffuse into the Bi0.5Na0.5TiO3 lattices to form a solid solution with a pure perovskite structure. As x increases from 0.05 to 0.50, the ceramics transform gradually from rhombohedral phase to tetragonal phase and consequently a morphotropic phase boundary (MPB) is formed at 0.15≤ x≤0.25. The concentration y of Li+ has no obvious influence on the crystal structure of the ceramics. Compared with pure Bi0.5Na0.5TiO3, the partial substitution of K+ and Li+ for Na+ lowers greatly the coercive field E c and increases the remanent polarization P r of the ceramics. Because of the MPB, lower E c and large P r, the piezoelectricity of the ceramics is improved significantly. For the ceramics with the compositions near the MPB ( x=0.15-0.25 and y=0.05-0.10), the piezoelectric properties become optimum: piezoelectric coefficient d 33=147-231 pC/N and planar electromechanical coupling factor k P=20.2-41.0%. In addition, the ceramics exhibit relaxor characteristic, which probably results from the cation disordering in the 12-fold coordination sites. The depolarization temperature T d shows a strong dependence on the concentration x of K+ and reaches the lowest values at the MPB. The temperature dependences of the ferroelectric and dielectric properties at high temperatures may imply that the ceramics may contain both the polar and non-polar regions at temperatures above T d.

  18. Advances in lead-free piezoelectric materials for sensors and actuators.

    PubMed

    Aksel, Elena; Jones, Jacob L

    2010-01-01

    Piezoelectrics have widespread use in today's sensor and actuator technologies. However, most commercially available piezoelectric materials, e.g., Pb [Zr(x)Ti(1-x)] O(3) (PZT), are comprised of more than 60 weight percent lead (Pb). Due to its harmful effects, there is a strong impetus to identify new lead-free replacement materials with comparable properties to those of PZT. This review highlights recent developments in several lead-free piezoelectric materials including BaTiO(3), Na(0.5)Bi(0.5)TiO(3), K(0.5)Bi(0.5)TiO(3), Na(0.5)K(0.5)NbO(3), and their solid solutions. The factors that contribute to strong piezoelectric behavior are described and a summary of the properties for the various systems is provided. PMID:22294907

  19. Advances in Lead-Free Piezoelectric Materials for Sensors and Actuators

    PubMed Central

    Aksel, Elena; Jones, Jacob L.

    2010-01-01

    Piezoelectrics have widespread use in today’s sensor and actuator technologies. However, most commercially available piezoelectric materials, e.g., Pb [ZrxTi1−x] O3 (PZT), are comprised of more than 60 weight percent lead (Pb). Due to its harmful effects, there is a strong impetus to identify new lead-free replacement materials with comparable properties to those of PZT. This review highlights recent developments in several lead-free piezoelectric materials including BaTiO3, Na0.5Bi0.5TiO3, K0.5Bi0.5TiO3, Na0.5K0.5NbO3, and their solid solutions. The factors that contribute to strong piezoelectric behavior are described and a summary of the properties for the various systems is provided. PMID:22294907

  20. Study of BNKLBT-1.5 lead-free ceramic/epoxy 1-3 composites

    NASA Astrophysics Data System (ADS)

    Choy, S. H.; Li, W. K.; Li, H. K.; Lam, K. H.; Chan, H. L. W.

    2007-12-01

    Bismuth sodium titanate based lead-free ceramic fiber with the chemical formula of 0.885(Bi0.5Na0.5)TiO3-0.05(Bi0.5K0.5)TiO3-0.015(Bi0.5Li0.5)TiO3-0.05BaTiO3, BNKLBT-1.5, has been fabricated by a powder-based extrusion method. The ceramic fibers with 400μm diameter were well crystallized after being calcined at 800°C and sintered at 1170°C. The piezoelectric and ferroelectric properties of the single fiber were found to be 155pC/N and ˜34.5μC/cm2, respectively, which is comparable with that in bulk sample. 1-3 ceramic/polymer composites were fabricated by two routes, including dice and filled method and fiber pick-and-place method. Theoretical models were used to calculate the piezoelectric properties of the composites and compared with experimental results.

  1. New potassium-sodium niobate material system: a giant-d?? and high-T(C) lead-free piezoelectric.

    PubMed

    Zheng, Ting; Wu, Jiagang; Cheng, Xiaojing; Wang, Xiaopeng; Zhang, Binyu; Xiao, Dingquan; Zhu, Jianguo; Lou, Xiaojie; Wang, Xiangjian

    2014-08-14

    In this work, we elucidate the influence of Bi(0.5)Li(0.5)ZrO3 (BLZ) content on the phase structure, microstructure, and electrical properties of (1 -x)K(0.40)Na(0.60)Nb(0.965)Sb(0.035)O3-xBi(0.5)Li(0.5)ZrO3 lead-free ceramics. We simultaneously achieved a giant d33 and a high T(C) in this material system. The coexistence of rhombohedral and tetragonal phases is responsible for such a large d33 in the ceramics with BLZ contents (x) ranging from 0.025 to 0.035. Doping with BLZ not only induces the formation of the phase boundary, but also maintains a high T(C). The ceramic with x = 0.03 shows an enhanced piezoelectric behaviour (d33 ~ 400 pC N(-1) and k(p) ~ 0.47) together with a high T(C) of 292 C. A good temperature stability for ferroelectricity and piezoelectricity is also observed in these ceramics. This study is the first time that such a good comprehensive performance has been obtained in potassium-sodium niobate materials. We believe that this type of material system possessing giant-d33 and high-T(C) is a promising candidate for use in high-temperature piezoelectric devices. PMID:24958201

  2. Piezoelectric Ceramics and Their Applications

    ERIC Educational Resources Information Center

    Flinn, I.

    1975-01-01

    Describes the piezoelectric effect in ceramics and presents a quantitative representation of this effect. Explains the processes involved in the manufacture of piezoelectric ceramics, the materials used, and the situations in which they are applied. (GS)

  3. Lead-Free Piezoelectric Diaphragm Biosensors Based on Micro-Machining Technology and Chemical Solution Deposition

    PubMed Central

    Li, Xiaomeng; Wu, Xiaoqing; Shi, Peng; Ye, Zuo-Guang

    2016-01-01

    In this paper, we present a new approach to the fabrication of integrated silicon-based piezoelectric diaphragm-type biosensors by using sodium potassium niobate-silver niobate (0.82KNN-0.18AN) composite lead-free thin film as the piezoelectric layer. The piezoelectric diaphragms were designed and fabricated by micro-machining technology and chemical solution deposition. The fabricated device was very sensitive to the mass changes caused by various targets attached on the surface of diaphragm. The measured mass sensitivity value was about 931 Hz/μg. Its good performance shows that the piezoelectric diaphragm biosensor can be used as a cost-effective platform for nucleic acid testing. PMID:26771617

  4. Lead-Free Piezoelectric Diaphragm Biosensors Based on Micro-Machining Technology and Chemical Solution Deposition.

    PubMed

    Li, Xiaomeng; Wu, Xiaoqing; Shi, Peng; Ye, Zuo-Guang

    2016-01-01

    In this paper, we present a new approach to the fabrication of integrated silicon-based piezoelectric diaphragm-type biosensors by using sodium potassium niobate-silver niobate (0.82KNN-0.18AN) composite lead-free thin film as the piezoelectric layer. The piezoelectric diaphragms were designed and fabricated by micro-machining technology and chemical solution deposition. The fabricated device was very sensitive to the mass changes caused by various targets attached on the surface of diaphragm. The measured mass sensitivity value was about 931 Hz/μg. Its good performance shows that the piezoelectric diaphragm biosensor can be used as a cost-effective platform for nucleic acid testing. PMID:26771617

  5. Effect of donor doping on the ferroelectric and the piezoelectric properties of lead-free 0.97(Bi0.5Na0.5Ti1- x Nb x )O3-0.03BaZrO3 ceramics

    NASA Astrophysics Data System (ADS)

    Rahman, Jamil Ur; Hussain, Ali; Maqbool, Adnan; Malik, Rizwan Ahmed; Song, Tae Kwon; Kim, Myong Ho; Lee, Soonil; Kim, Won Jeong

    2015-10-01

    Lead-free piezoelectric 0.97(Bi0.5Na0.5Ti1- x Nb x )O3-0.03BaZrO3 (BNT-BZ3) ceramics ( x = 0 ~ 0.03) were prepared by a conventional solid-state reaction method. X-ray diffraction patterns revealed the formation of single-phase perovskite structure with x ≤ 0.015. The depolarization temperature and the dielectric constant decreased with increasing Nb content. The remanent polarization (Pr) and the piezoelectric constant (d33) increased from 28 μC/cm2 and 98 pC/N for x = 0 to 31 μC/cm2 and 128 pC/N for x = 0.005, respectively. In addition, the electric field induced strain was enhanced with a maximum value S max = 0.17% with a normalized piezoelectric coefficient of d*33 = 283 pm/V at an applied electric field of 6 kV/mm for x = 0.015.

  6. Development of Bismuth-based Lead-free Piezoelectric Materials: Thin Film Piezoelectric Materials via PVD and CSD Routes

    NASA Astrophysics Data System (ADS)

    Jeon, Yu Hong

    Piezoelectric materials have been widely used in electromechanical actuators, sensors, and ultrasonic transducers. Among these materials, lead zirconate titanate Pb(Zr1-xTix)O3 (PZT) has been primarily investigated due to its excellent piezoelectric properties. However, environmental concerns due to the toxicity of PbO have led to investigations into alternative materials systems. Bismuth-based perovskite piezoelectric materials such as (Bi0.5,Na0.5)TiO3 - (Bi0.5K 0.5)TiO3 (BNT - BKT), (Bi0.5,Na0.5 )TiO3 - (Bi0.5K0.5)TiO3 - BaTiO3(BNT - BKT - BT), (Bi0.5K 0.5)TiO3 - Bi(Zn0.5,Ti0.5)O 3 (BKT - BZT), and (Bi0.5,Na0.5)TiO 3 - (Bi0.5K0.5)TiO3 - Bi(Mg 0.5,Ti0.5)O3 (BNT - BKT - BMgT) have been explored as potential alternatives to PZT. These materials systems have been extensively studied in bulk ceramic form, however many of the ultimate applications will be in thin film embodiments (i.e., microelectromechanical systems). For this reason, in this thesis these lead-free piezoelectrics are synthesized in thin film form to understand the structure-property-processing relationships and their impact on the ultimate device response. Fabrication of high quality of 0.95BKT - 0.05BZT thin films on platinized silicon substrates was attempted by pulsed laser deposition. Due to cation volatility, deposition parameters such as substrate temperature, deposition pressure, and target-substrate distance, as well as target overdoping were explored to achieve phase pure materials. This route led to high dielectric loss, indicative of poor ferroelectric behavior. This was likely a result of the poor thin film morphology observed in films deposited via this method. Subsequently, 0.8BNT - 0.2BKT, 85BNT - 10BKT - 5BT, and 72.5BNT - 22.5BKT - 5BMgT (near morphotropic phase boundary composition) were synthesized via chemical solution deposition. To compensate the loss of A-site cations, overdoped precursor solutions were prepared. Crystallization after each spin cast layer were required to produce phase pure material. Good permittivities and low dielectric loss over the frequency range of 100 Hz to 1 MHz were obtained. Dependent upon annealing conditions, various film morphologies and compositional distributions were observed via electron microscopy and composition measurements. As opposed to previously reported work, good ferroelectric response at low frequency (200 Hz) were found. For BNT - BKT - BMgT, the maximum polarization was over 50 μC/cm2 with high d33,fof 75 pm/V were obtained. Additionally, the extrinsic and intrinsic contributions to the dielectric response for solution-derived BNT - BKT and BNT - BKT - BMgT films were studied via Rayleigh analysis. For sub-switching fields a good agreement between predicted polarization behavior from Rayleigh analysis and experimentally measured polarization indicated the validity of this approach for BNT-based thin films. Results of this thesis proved that high quality bismuth-based piezoelectric thin films with good electrical response can be fabricated with suppression of cation volatility for various processing conditions. Furthermore, these thin films can be considered as alternatives to PZT thin films as potential candidates for piezoelectric-based microelectromechanical systems (MEMS).

  7. Lead-free LiNbO3 nanowire-based nanocomposite for piezoelectric power generation

    PubMed Central

    2014-01-01

    In a flexible nanocomposite-based nanogenerator, in which piezoelectric nanostructures are mixed with polymers, important parameters to increase the output power include using long nanowires with high piezoelectricity and decreasing the dielectric constant of the nanocomposite. Here, we report on piezoelectric power generation from a lead-free LiNbO3 nanowire-based nanocomposite. Through ion exchange of ultra-long Na2Nb2O6-H2O nanowires, we synthesized long (approximately 50 μm in length) single-crystalline LiNbO3 nanowires having a high piezoelectric coefficient (d33 approximately 25 pmV-1). By blending LiNbO3 nanowires with poly(dimethylsiloxane) (PDMS) polymer (volume ratio 1:100), we fabricated a flexible nanocomposite nanogenerator having a low dielectric constant (approximately 2.7). The nanogenerator generated stable electric power, even under excessive strain conditions (approximately 105 cycles). The different piezoelectric coefficients of d33 and d31 for LiNbO3 may have resulted in generated voltage and current for the e33 geometry that were 20 and 100 times larger than those for the e31 geometry, respectively. This study suggests the importance of the blending ratio and strain geometry for higher output-power generation in a piezoelectric nanocomposite-based nanogenerator. PACS 77.65.-j; 77.84.-s; 73.21.Hb PMID:24386884

  8. Lead-free LiNbO3 nanowire-based nanocomposite for piezoelectric power generation.

    PubMed

    Yun, Byung Kil; Park, Yong Keun; Lee, Minbaek; Lee, Nuri; Jo, William; Lee, Seongsu; Jung, Jong Hoon

    2014-01-01

    In a flexible nanocomposite-based nanogenerator, in which piezoelectric nanostructures are mixed with polymers, important parameters to increase the output power include using long nanowires with high piezoelectricity and decreasing the dielectric constant of the nanocomposite. Here, we report on piezoelectric power generation from a lead-free LiNbO3 nanowire-based nanocomposite. Through ion exchange of ultra-long Na2Nb2O6-H2O nanowires, we synthesized long (approximately 50 μm in length) single-crystalline LiNbO3 nanowires having a high piezoelectric coefficient (d33 approximately 25 pmV-1). By blending LiNbO3 nanowires with poly(dimethylsiloxane) (PDMS) polymer (volume ratio 1:100), we fabricated a flexible nanocomposite nanogenerator having a low dielectric constant (approximately 2.7). The nanogenerator generated stable electric power, even under excessive strain conditions (approximately 105 cycles). The different piezoelectric coefficients of d33 and d31 for LiNbO3 may have resulted in generated voltage and current for the e33 geometry that were 20 and 100 times larger than those for the e31 geometry, respectively. This study suggests the importance of the blending ratio and strain geometry for higher output-power generation in a piezoelectric nanocomposite-based nanogenerator. PACS: 77.65.-j; 77.84.-s; 73.21.Hb. PMID:24386884

  9. Large electric field-induced strain and piezoelectric responses of lead-free Bi0.5(Na0.80K0.20)0.5TiO3-Ba(Ti0.90Sn0.10)O3 ceramics near morphotropic phase boundary

    NASA Astrophysics Data System (ADS)

    Jaita, Pharatree; Watcharapasorn, Anucha; Kumar, Nitish; Cann, David P.; Jiansirisomboon, Sukanda

    2015-09-01

    Lead-free piezoelectric ceramics with compositions belonging to family of compositions (1- x)Bi0.5(Na0.80K0.20)0.5TiO3- xBa(Ti0.90Sn0.10)O3 or (1- x) BNKT- xBTS (when x = 0.05 - 0.15 mol fraction) near the morphotropic phase boundary (MPB) were fabricated by a conventional mixed oxide method. Sintered samples had relative densities greater than 98% of their theoretical values. X-ray diffraction data revealed that the MPB region consisted of coexisting rhombohedral and tetragonal phases in the BNKT-BTS system was identified over the entire compositional range. A large electric field-induced strain ( S max ) of 0.36% and a normalized strain coefficient ( d*33) of 649 pm/V were observed in the BNKT-0.05BTS sample. The sample close to the MPB composition (BNKT-0.11BTS) exhibited the maximum dielectric constant ( ɛ r = 1770), temperature of maximum permittivity ( T m = 333C°) and low-field piezoelectric coefficient ( d 33 = 227 pC/N), along with reasonable ferroelectric properties ( P r = 20.6 mC/cm2, R sq = 0.88) and strain properties ( d*33 = 445 pm/V and S max = 0.24%). [Figure not available: see fulltext.

  10. Phase structure, microstructure, and electrical properties of bismuth modified potassium-sodium niobium lead-free ceramics

    NASA Astrophysics Data System (ADS)

    Du, Hongliang; Luo, Fa; Qu, Shaobo; Pei, Zhibin; Zhu, Dongmei; Zhou, Wancheng

    2007-09-01

    (K0.5Na0.5)1-3xBixNbO3 (KNBN) ceramics were prepared by conventional solid-state sintering without cold-isostatic pressing. The phase structure, microstructure, and electrical properties of KNBN ceramics are studied. The phase structure of KNBN ceramics (x =0.01) is pure perovskite phase with orthorhombic symmetry at room temperature. The addition of Bi3+ significantly improves electrical properties of (K0.5Na0.5)NbO3 ceramics while keeping the tetragonal-orthorhombic phase transition temperature above 170 °C. The KNBN (x=0.01) ceramics show the optimum electrical properties (d33=164 pC/N, kp=0.47, Qm=120, TC=403 °C, TO-T=174 °C, Pr=30.1 μC/cm2, and Ec=6.18 kV/cm). Take into account electrical properties and the polymorphic phase transition temperature (TO-T), it can be concluded that the KNBN (x =0.01) ceramic is a promising lead-free piezoelectric candidate material for practical application. The related mechanisms for high piezoelectric properties in KNBN (x =0.01) ceramics are also discussed.

  11. Evaluation of the performance of a lead-free piezoelectric material for energy harvesting

    NASA Astrophysics Data System (ADS)

    Machado, S. P.; Febbo, M.; Rubio-Marcos, F.; Ramajo, L. A.; Castro, M. S.

    2015-11-01

    Vibration-based energy harvesting has been explored as an auxiliary power source, which can provide small amounts of energy to power remote sensors installed in inaccessible locations. This paper presents an experimental and analytical study of an energy harvesting device using a lead-free piezoelectric material based on {{MoO}}3-doped ({{{K}}}0.44{{Na}}0.52{{Li}}0.04)({{Nb}}0.86{{Ta}}0.10{{Sb}}0.04){{{O}}}3 KNL-(NTS)Mo. The harvesting model corresponds to a cantilever beam with a KNL-(NTS)Mo piezoelectric disc attached to it. We analyze the effect of electromechanical coupling and load resistance on the generated electrical power. Electromechanical frequency response functions that relate the voltage output to the translational base acceleration are shown for experimental and analytical results.

  12. Properties of lead-free BZT-BCT ceramics synthesized using nanostructured ZnO as a sintering aid

    NASA Astrophysics Data System (ADS)

    Tuan, Dang Anh; Tung, Vo Thanh; Chuong, Truong Van; Hong, Le Van

    2015-11-01

    This article studies the microstructure and piezoelectric properties of low sintering temperature lead-free ceramics 0.52(Ba0.7Ca0.3)TiO3 ? 0.48Ba(Zr0.2Ti0.8)O3-doped with ZnO nanoparticles (noted as 0.48BZT-y, y is content of ZnO in wt%, y =0.00, 0.05, 0.10, 0.15, 0.20 and 0.25). The obtained results of Raman scattering and dielectric measurements have confirmed that Zn2+ has occupied B site, to cause a deformation in the ABO3-type lattice of the 0.48BZT-y compounds. The 0.15wt% ZnO-doped ceramic sintered at 1350?C exhibited excellent piezoelectric parameters: d33 = 420pC/N, d31 = ?174pC/N, kp = 0.483, kt = 0.423 and k33 = 0.571. The obtained results indicate that the high-quality lead-free BZT-BCT ceramic could be successfully synthesized at a low sintering temperature of 1350?C by doping an appropriated amount of ZnO.

  13. Electric fatigue process in lead-free alkali niobate ceramics at various pressures and temperatures

    NASA Astrophysics Data System (ADS)

    Martin, Alexander; Kakimoto, Ken-ichi

    2015-10-01

    Electric fatigue tests are important for evaluating the reliability of piezoceramics. However, these tests have not been the focus of studies of lead-free alkali niobate (NKN) ceramics so far. For this purpose, two different materials, Li0.06Na0.47K0.47NbO3 (LNKN6) and Na0.55K0.45NbO3 + 0.25% MnO (Mn-NKN), have been examined at various uniaxial pressures ranging from 0.1 to 100 MPa and various temperatures ranging from room temperature to 150 °C. It was shown that the harder ferroelectric Mn-NKN could maintain its piezoelectric properties at pressures up to 25 MPa. When bipolar fatigue occurred under pressures over the coercive stress of ∼30 MPa, the sample depolarized and formed microcracks. In contrast, the softer LNKN6 did not show fatigue at higher pressures between 25 and 50 MPa. However, in both materials, higher temperatures enhanced domain wall and charge carrier movements and conclusively domain wall pinning.

  14. Enhancement of the electrical-field-induced strain in lead-free Bi0.5(Na,K)0.5TiO3-based piezoelectric ceramics: Role of the phase transition

    NASA Astrophysics Data System (ADS)

    Quyet, Nguyen Van; Bac, Luong Huu; Dung, Dang Duc

    2015-04-01

    In this work, a strong enhancement of the electric-field-induced strain in Bi0.5(Na,K)0.5TiO3-based ceramics was observed via lithium(Li) addition. The Li-added Bi0.5(Na,K)0.5TiO3-based ceramics exhibited a strain of 0.40% under an electric field of 6 kV/mm, which was almost twice the value without the Li dopant (0.21%). We obtained the highest S max/ E max value of 668 pm/V for 4-mol% Li addition, which was due to the phase transition from pseudocubic to rhombohedral symmetry and/or to the distorted tetragonal structure. We suggest that controlling the phase transition in ferroelectric materials is a way to enhance the electric-field-induced giant strain and that the phase transition from the non-polar phase to the polar phase results in a giant electric-fieldinduced strain, which overcomes the result due to the phase transition from the polar phase to the non-polar phase and/or the distorted structure. We expect our work to open new ways to enhance the electric-filed-induced giant strain to a value that is comparable to the value for Pb(Zr,Ti)O3 (PZT)-based ceramics.

  15. Dramatic influence of Dy3+ doping on strain and domain structure in lead-free piezoelectric 0.935(Na1/2Bi1/2)TiO3-0.065BaTiO3 ceramics

    NASA Astrophysics Data System (ADS)

    Li, C. Q.; Yao, Q. R.; Zhang, J. Z.; Hu, Z. G.; Wang, F. F.; Liu, A. Y.; Shi, W. Z.; Chu, J. H.

    2015-12-01

    An electric-field induced giant strain response and doping level dependent domain structural variations have been studied in the dysprosium (Dy3+)-modified 0.935(Na1/2Bi1/2)TiO3-0.065BaTiO3(xDy : NBBT) ceramics with the doping levels of 0%, 0.5%, 1%, and 2%. X-ray diffraction and Raman spectroscopy analyses not only demonstrates the change in ionic configurations induced by Dy3+ doping, but also shows the local crystal symmetry for x ≥ 0.5% doping levels to deviate from the idealized cubic structure. Piezoresponse force microscopy measurement exhibits the presence of an intermediate phase with orthorhombic symmetry at the critical Dy3+ doping level of 2%. Moreover, at this doping level, a giant recoverable nonlinear strain of ˜0.44% can be observed with high normalized strain (Smax/Emax) of 728 pm/V. At the same applied field, the strain exhibits a 175% increase than that of NBBT ceramic. Such a large strain stems from the varying coherence lengths of polar nanoregions (PNRs) and an unusual reversible 90° domain switching caused by the symmetry conforming property of point defects, where the restoring force is provided by unswitchable defects. The mechanism reveals a new possibility to achieve large electric-field strain effect for a wide range of ferroelectric systems, which can lead to applications in novel "on-off" actuators.

  16. Lead-free piezoelectric KNN-BZ-BNT films with a vertical morphotropic phase boundary

    NASA Astrophysics Data System (ADS)

    Chen, Wen; Zhao, Jinyan; Wang, Lingyan; Ren, Wei; Liu, Ming

    2015-07-01

    The lead-free piezoelectric 0.915K0.5Na0.5NbO3-0.075BaZrO3-0.01Bi0.5Na0.5TiO3 (0.915KNN-0.075BZ-0.01BNT) films were prepared by a chemical solution deposition method. The films possess a pure rhomobohedral perovskite phase and a dense surface without crack. The temperature-dependent dielectric properties of the specimens manifest that only phase transition from ferroelectric to paraelectric phase occurred and the Curie temperature is 217 oC. The temperature stability of ferroelectric phase was also supported by the stable piezoelectric properties of the films. These results suggest that the slope of the morphotropic phase boundary (MPB) for the solid solution formed with the KNN and BZ in the films should be vertical. The voltage-induced polarization switching, and a distinct piezo-response suggested that the 0.915 KNN-0.075BZ-0.01BNT films show good piezoelectric properties.

  17. Large Field-Induced Strain Properties of Sr(K0.25Nb0.75) O3-Modified Bi1/2(Na0.82K0.18)1/2TiO3 Lead-Free Piezoelectric Ceramics

    NASA Astrophysics Data System (ADS)

    Tran, Vu Diem Ngoc; Ullah, Aman; Dinh, Thi Hinh; Lee, Jae-Shin

    2016-03-01

    Lead-free piezoelectric ceramics with compositions of (1 - x)Bi1/2(Na0.82 K0.18)1/2TiO3 + xSr(K0.25Nb0.75)O3, which are abbreviated as (1 - x)BNKT-xSKN with x = 0, 0.01, 0.02, 0.03, 0.04, and 0.05, were synthesized using a conventional solid-state reaction method. The effects of SKN addition on the BNKT system were examined in terms of the phase transition, strain behavior, and ferroelectric and dielectric properties. X-ray diffraction revealed a single perovskite phase for all compositions. The results showed that with increasing SKN content, BNKT-SKN underwent a phase transition from the coexistence of rhombohedral and tetragonal phases to a tetragonal phase. The addition of SKN shifted the depolarization temperature, T d, to a lower temperature and enhanced the diffuseness of the dielectric peaks. The polarization and bipolar strain hysteresis loops of BNKT-SKN showed that the addition of SKN induced a ferroelectric to ergodic relaxor phase transition with a disruption of the ferroelectric order of pure BNKT. As a result, the strain of BNKT-SKN improved significantly with increasing SKN content and reached the highest value of a normalized strain, S max/E max, of 557 pm/V, when modified with 3 mol.% SKN.

  18. Large Field-Induced Strain Properties of Sr(K0.25Nb0.75) O3-Modified Bi1/2(Na0.82K0.18)1/2TiO3 Lead-Free Piezoelectric Ceramics

    NASA Astrophysics Data System (ADS)

    Tran, Vu Diem Ngoc; Ullah, Aman; Dinh, Thi Hinh; Lee, Jae-Shin

    2016-05-01

    Lead-free piezoelectric ceramics with compositions of (1 - x)Bi1/2(Na0.82 K0.18)1/2TiO3 + xSr(K0.25Nb0.75)O3, which are abbreviated as (1 - x)BNKT- xSKN with x = 0, 0.01, 0.02, 0.03, 0.04, and 0.05, were synthesized using a conventional solid-state reaction method. The effects of SKN addition on the BNKT system were examined in terms of the phase transition, strain behavior, and ferroelectric and dielectric properties. X-ray diffraction revealed a single perovskite phase for all compositions. The results showed that with increasing SKN content, BNKT-SKN underwent a phase transition from the coexistence of rhombohedral and tetragonal phases to a tetragonal phase. The addition of SKN shifted the depolarization temperature, T d, to a lower temperature and enhanced the diffuseness of the dielectric peaks. The polarization and bipolar strain hysteresis loops of BNKT-SKN showed that the addition of SKN induced a ferroelectric to ergodic relaxor phase transition with a disruption of the ferroelectric order of pure BNKT. As a result, the strain of BNKT-SKN improved significantly with increasing SKN content and reached the highest value of a normalized strain, S max/ E max, of 557 pm/V, when modified with 3 mol.% SKN.

  19. Morphotropic phase boundary and electrical properties of K1-xNaxNbO3 lead-free ceramics

    NASA Astrophysics Data System (ADS)

    Dai, Ye-Jing; Zhang, Xiao-Wen; Chen, Ke-Pi

    2009-01-01

    Lead-free K1-xNaxNbO3 ceramics with x =0.48-0.54 were prepared by a conventional solid-state reaction method to investigate the influence of the K/Na ratio on phase structures and electrical properties. The results suggest that a typical morphotropic phase boundary exists at x =0.52-0.525, separating the monoclinic and orthorhombic phases. The sample with the composition near x =0.52 shows the maximum values of the piezoelectric constant (d33=160 pC/N) and the electromechanical coupling coefficient (kt=47%). The results provide a helpful guidance to consider the optimal ratio of K to Na for designing and developing new (K,Na)NbO3-based ceramics.

  20. Lead-free piezoceramics

    NASA Astrophysics Data System (ADS)

    Saito, Yasuyoshi; Takao, Hisaaki; Tani, Toshihiko; Nonoyama, Tatsuhiko; Takatori, Kazumasa; Homma, Takahiko; Nagaya, Toshiatsu; Nakamura, Masaya

    2004-11-01

    Lead has recently been expelled from many commercial applications and materials (for example, from solder, glass and pottery glaze) owing to concerns regarding its toxicity. Lead zirconium titanate (PZT) ceramics are high-performance piezoelectric materials, which are widely used in sensors, actuators and other electronic devices; they contain more than 60 weight per cent lead. Although there has been a concerted effort to develop lead-free piezoelectric ceramics, no effective alternative to PZT has yet been found. Here we report a lead-free piezoelectric ceramic with an electric-field-induced strain comparable to typical actuator-grade PZT. We achieved this through the combination of the discovery of a morphotropic phase boundary in an alkaline niobate-based perovskite solid solution, and the development of a processing route leading to highly <001> textured polycrystals. The ceramic exhibits a piezoelectric constant d33 (the induced charge per unit force applied in the same direction) of above 300picocoulombs per newton (pCN-1), and texturing the material leads to a peak d33 of 416pCN-1. The textured material also exhibits temperature-independent field-induced strain characteristics.

  1. Synthesis of highly piezoelectric lead-free (K, Na)NbO3 one-dimensional perovskite nanostructures.

    PubMed

    Cheng, Li-Qian; Wang, Ke; Li, Jing-Feng

    2013-05-11

    High-aspect-ratio single-crystalline KNN nanorods (length ~10-20 ?m and diameter ~400 nm) are synthesized using a facile method based on a molten-salt reaction, whose formation mechanism has been revealed. The lead-free piezoelectric nanorods showing high piezoelectric coefficient d*33 up to ~230 pm V(-1) may be used in bio-sensing and energy-harvesting micro-devices. PMID:23558560

  2. Preparation and piezoelectric properties of potassium sodium niobate glass ceramics

    NASA Astrophysics Data System (ADS)

    Jiang, Shan; Wang, Xuan-Ming; Li, Jia-Yu; Zhang, Yong; Zheng, Tao; Lv, Jing-Wen

    2015-06-01

    This paper describes the preparation of a piezoelectric glass ceramic material from potassium sodium niobate (K0.5Na0.5NbO3; KNN) using a novel melting method. The effects of the subsequent heat-treatment on the optical, thermal, electrical, and mechanical properties of the material are carefully examined, and its crystal structure and surface morphology are characterized respectively by x-ray diffraction and scanning electron microscopy. This new material has a much higher piezoelectric coefficient (163 pC·N-1) than traditional piezoelectric ceramics (131 pC·N-1). On this basis therefore, a strategy for the future study and development of lead-free KNN-based piezoelectric glass ceramics is proposed.

  3. Bar piezoelectric ceramic transformers.

    PubMed

    Erhart, Ji?; Pulpan, P?lpn; Rusin, Lubo

    2013-07-01

    Bar-shaped piezoelectric ceramic transformers (PTs) working in the longitudinal vibration mode (k31 mode) were studied. Two types of the transformer were designed--one with the electrode divided into two segments of different length, and one with the electrodes divided into three symmetrical segments. Parameters of studied transformers such as efficiency, transformation ratio, and input and output impedances were measured. An analytical model was developed for PT parameter calculation for both two- and three-segment PTs. Neither type of bar PT exhibited very high efficiency (maximum 72% for three-segment PT design) at a relatively high transformation ratio (it is 4 for two-segment PT and 2 for three-segment PT at the fundamental resonance mode). The optimum resistive loads were 20 and 10 k? for two- and three-segment PT designs for the fundamental resonance, respectively, and about one order of magnitude smaller for the higher overtone (i.e., 2 k? and 500 ?, respectively). The no-load transformation ratio was less than 27 (maximum for two-segment electrode PT design). The optimum input electrode aspect ratios (0.48 for three-segment PT and 0.63 for two-segment PT) were calculated numerically under no-load conditions. PMID:25004515

  4. Disc piezoelectric ceramic transformers.

    PubMed

    Erhart, Jirií; Půlpán, Petr; Doleček, Roman; Psota, Pavel; Lédl, Vít

    2013-08-01

    In this contribution, we present our study on disc-shaped and homogeneously poled piezoelectric ceramic transformers working in planar-extensional vibration modes. Transformers are designed with electrodes divided into wedge, axisymmetrical ring-dot, moonie, smile, or yin-yang segments. Transformation ratio, efficiency, and input and output impedances were measured for low-power signals. Transformer efficiency and transformation ratio were measured as a function of frequency and impedance load in the secondary circuit. Optimum impedance for the maximum efficiency has been found. Maximum efficiency and no-load transformation ratio can reach almost 100% and 52 for the fundamental resonance of ring-dot transformers and 98% and 67 for the second resonance of 2-segment wedge transformers. Maximum efficiency was reached at optimum impedance, which is in the range from 500 Ω to 10 kΩ, depending on the electrode pattern and size. Fundamental vibration mode and its overtones were further studied using frequency-modulated digital holographic interferometry and by the finite element method. Complementary information has been obtained by the infrared camera visualization of surface temperature profiles at higher driving power. PMID:25004532

  5. Comparative study of 2mol% Li- and Mn-substituted lead-free potassium sodium niobate ceramics

    NASA Astrophysics Data System (ADS)

    Dahiya, Asha; Thakur, O. P.; Juneja, J. K.; Singh, Sangeeta; Dipti

    2014-12-01

    The effect of Li and Mn substitution on the dielectric, ferroelectric and piezoelectric properties of lead free K0.5Na0.5NbO3 (KNN) was investigated. Samples were prepared using a conventional solid state reaction method. The sintering temperature for all the samples was 1050°C. The optimum doping concentration for the enhancement of different properties without the introduction of any other co-dopants such as Ti, Sb, and La was investigated. X-ray diffraction analysis confirmed that all the samples crystallize in a single phase perovskite structure. The dielectric properties were investigated as a function of temperature and applied electric field frequency. Compared with Li-substituted KNN (KLNN), Mn-substituted KNN (KMNN) exhibited a higher dielectric constant ɛ max (i.e., 4840) at its critical transition temperature T c (i.e., 421°C) along with a lower value of tangent loss at 10 kHz and greater values of saturation polarisation P s (i.e., 20.14 μC/cm2) and remnant polarisation P r (i.e., 15.48 μC/cm2). The piezoelectric constant ( d 33) of KMNN was 178 pC/N, which is comparable to that of lead-based hard ceramics. The results presented herein suggest that B-site or Mn substitution at the optimum concentration results in good enhancement of different properties required for materials used in memory devices and other applications.

  6. High power density NaNbO3-LiTaO3 lead-free piezoelectric transformer in radial vibration modes

    NASA Astrophysics Data System (ADS)

    Sun, H. L.; Lin, D. M.; Lam, K. H.; Guo, M. S.; Choy, S. H.; Kwok, K. W.; Chan, H. L. W.

    2015-06-01

    In the present work, the sintering temperature was able to substantially influence the microstructure and electrical properties of the lead-free ceramic 0.88NaNbO3-0.12LiTaO3. This composition without any acceptor doping presents a high mechanical quality factor, Qm, value of 1469 and a high Curie temperature of 305 °C by optimizing the sintering temperature at 1330 °C. We applied this material to make a device of disk-shaped piezoelectric transformers with a ring-dot structure and further focused on investigating the characteristics of the piezoelectric transformers. With matching load, a maximum efficiency of 92% occurs in the fundamental mode, and the maximum voltage gains are 5.5 and 3.7 for the fundamental and third radial vibration modes, respectively. The experimental results show a maximum output power of 10.5 W with a temperature rise of 27 °C. It is noteworthy that a high output power density (as high as 32.8 W cm-3) was obtained under a maximum input voltage of 180 V, which is comparable to the performance of PZT in a piezoelectric ceramic transformer device.

  7. Lead-free BFN ceramics doped by chromium, lithium or manganese

    NASA Astrophysics Data System (ADS)

    Bochenek, Dariusz; Niemiec, Przemysław; Adamczyk, Małgorzata

    2015-10-01

    The material of the study was lead-free BaFe0.5Nb0.5O3 ceramics subject to modification. The base composition BaFe0.5Nb0.5O3 as well as the chromium, lithium and manganese modified ones were obtained using conventional mixed oxides and carbonates method. Synthesis was performed by the powder calcination method at high temperature 1250 °C for 4 h, while the densification was carried out by free sintering method under conditions 1350 °C/4 h. The paper presents a complex study of admixtures influence on the crystal structure, microstructure and dielectric properties of the BFN type samples. The mentioned dopants chromium, lithium or manganese in the BFN-type ceramics among other caused the reduction of the electric permittivity maximum as well as significant decrease in value of dielectric loss.

  8. Phase-transition temperatures and piezoelectric properties of (Bi1/2Na1/2)TiO3-(Bi1/2Li1/2)TiO3-(Bi1/2K1/2)TiO3 lead-free ferroelectric ceramics.

    PubMed

    Hiruma, Yuji; Nagata, Hajime; Takenaka, Tadashi

    2007-12-01

    The phase-transition temperatures and piezoelectric properties of x(Bi(1/2)Na(1/2))TiO3-y(Bi(1/2)Li(1/2))TiO3-z(Bi(1/2)K(1/2))TiO3 [x + y + z = 1] (abbreviated as BNLKT100(y)-100(z)) ceramics were investigated. These ceramics were prepared using a conventional ceramic fabrication process. The phase-transition temperatures such as depolarization temperatures T(d), rhombohedraltetragonal phase transition temperature T(R-T), and dielectric-maximum temperature T(m) were determined using electrical measurements such as dielectric and piezoelectric properties. The X-ray powder diffraction patterns of BNLKT100(y)-100(z)) show the morphotropic phase boundary (MPB) between rhombohedral and tetragonal at approximately z = 0.20, and the piezoelectric properties show the maximum at the MPB. The electromechanical coupling factor k(33), piezoelectric constant d(33) and T(d) of BNLKT4-20 and BNLKT8-20 were 0.603, 176 pC/N, and 171 degrees C, and 0.590, 190 pC/N, and 115 degrees C, respectively. In addition, the relationship between d33 and Td of tetragonal side and rhombohedral side for BNLKT4-100z and BNLKT8-100z were presented. Considering both high Td and high d(33), the tetragonal side of BNLKT4-100z is thought to be the superior composition. The d(33) and T(d) of BNLKT4-28 were 135 pC/N and 218 degrees C, respectively. Moreover, this study revealed that the variation of T(d) is related to the variation of lattice distortion such as rhombohedrality 90-alpha and tetragonality c/a. PMID:18276544

  9. Piezoelectric and ferroelectric properties of lead-free niobium-rich potassium lithium tantalate niobate single crystals

    SciTech Connect

    Li, Jun; Li, Yang; Zhou, Zhongxiang; Guo, Ruyan; Bhalla, Amar S.

    2014-01-01

    Graphical abstract: - Highlights: • Lead-free K{sub 0.95}Li{sub 0.05}Ta{sub 1−x}Nb{sub x}O{sub 3} single crystals were grown using the top-seeded melt growth method. • The piezoelectric and ferroelectric properties of as-grown crystals were systematically investigated. • The piezoelectric properties are very attractive, e.g. for x = 0.60 composition, k{sub t} ≈ 70%, k{sub 31} ≈ 70%, k{sub 33} ≈ 77%, d{sub 31} ≈ 230 pC/N, d{sub 33} ≈ 600 pC/N. • The coercive fields of P–E hysteresis loops are quite small, about or less than 1 kV/mm. - Abstract: Lead-free potassium lithium tantalate niobate single crystals with the composition of K{sub 0.95}Li{sub 0.05}Ta{sub 1−x}Nb{sub x}O{sub 3} (abbreviated as KLTN, x = 0.51, 0.60, 0.69, 0.78) were grown using the top-seeded melt growth method. Their piezoelectric and ferroelectric properties in as-grown crystals have been systematically investigated. The phase transitions and Curie temperatures were determined from dielectric and pyroelectric measurements. Piezoelectric coefficients and electromechanical coupling factors in thickness mode, length-extensional mode and longitudinal mode were obtained. The piezoelectric properties are very attractive, e.g. for x = 0.60 composition, k{sub t} ≈ 70%, k{sub 31} ≈ 70%, k{sub 33} ≈ 77%, d{sub 31} ≈ 230 pC/N, d{sub 33} ≈ 600 pC/N are comparable to the lead-based PZT composition. The polarization versus electric field hysteresis loops show saturated shapes. In short, lead-free niobium-rich KLTN system possesses comparable properties to those in important lead-based piezoelectric material nowadays.

  10. Electrocaloric enhancement near the morphotropic phase boundary in lead-free NBT-KBT ceramics

    NASA Astrophysics Data System (ADS)

    Le Goupil, Florian; Bennett, James; Axelsson, Anna-Karin; Valant, Matjaz; Berenov, Andrey; Bell, Andrew J.; Comyn, Tim P.; Alford, Neil McN.

    2015-10-01

    The electrocaloric effects (ECEs) of the morphotropic phase boundary (MPB) composition 0.82(Na0.5Bi0.5)TiO3-0.18(K0.5Bi0.5)TiO3 (NBT-18KBT) are studied by direct measurements. The maximum ECE ΔTmax = 0.73 K is measured at 160 °C under 22 kV/cm. This corresponds to an ECE responsivity (ΔT/ΔE) of 0.33 × 10-6 K m/V, which is comparable with the best reported values for lead-free ceramics. A comparison between the direct and indirect ECE measurements shows significant discrepancies. The direct measurement of both positive and negative electrocaloric effect confirms the presence of numerous polar phases near the MPB of NBT-based materials and highlights their potential for solid-state cooling based on high field-induced entropy changes.

  11. Enhancing electromechanical properties of lead-free ferroelectrics with bilayer ceramic/ceramic composites.

    PubMed

    Ayrikyan, Azatuhi; Rojas, Virginia; Molina-Luna, Leopoldo; Acosta, Matias; Koruza, Jurij; Webber, Kyle G

    2015-06-01

    The macroscopic electromechanical behavior of lead-free bilayer composites was characterized at room temperature. One layer consisted of a nonergodic relaxor, (Bi1/2Na1/2)TiO3-7BaTiO3, with an electric-field-induced longrange ferroelectric order, whereas the other is understood to be an ergodic relaxor [(Bi1/2Na1/2)TiO3-25SrTiO3] that undergoes a reversible electric-field-induced macroscopic nonpolar-to-polar transition. Microstructural evidence of a bilayer with low diffusion between the two components is also demonstrated. By taking advantage of the different macroscopic strain- and polarization-electric-field responses of the two constituents, internal mechanical and electrical fields can be developed that enhance the unipolar strain over that expected by a rule of mixtures approximation, thereby improving the properties needed for application of such materials to actuator systems. It is possible through further tailoring of the volume fractions and macroscopic properties of the constituents to optimize the electromechanical properties of multilayer lead-free ferroelectrics. PMID:26067034

  12. Nanoscale Atomic Displacements Ordering for Enhanced Piezoelectric Properties in Lead-Free ABO3 Ferroelectrics.

    PubMed

    Pramanick, Abhijit; Jørgensen, Mads R V; Diallo, Souleymane O; Christianson, Andrew D; Fernandez-Baca, Jaime A; Hoffmann, Christina; Wang, Xiaoping; Lan, Si; Wang, Xun-Li

    2015-08-01

    In situ synchrotron X-ray diffuse scattering and inelastic neutron scattering measurements from a prototype ABO3 ferroelectric single-crystal are used to elucidate how electric fields along a nonpolar direction can enhance its piezoelectric properties. The central mechanism is found to be a nanoscale ordering of B atom displacements, which induces increased lattice instability and therefore a greater susceptibility to electric-field-induced mechanical deformation. PMID:26076654

  13. Site engineering and polarization characteristics in (Ba1-yCay)(Ti1-xHfx)O3 lead-free ceramics

    NASA Astrophysics Data System (ADS)

    Zhao, Chunlin; Wu, Wenjuan; Wang, Hui; Wu, Jiagang

    2016-01-01

    Here we improved both piezoelectricity and strain of BaTiO3-based ceramics using composition designs and the optimization of poling conditions. In this work, the (Ba1-yCay)(Ti1-xHfx)O3 lead-free ceramics were fabricated by a conventional solid-state reaction method, and we systematically investigated the composition dependence of their phase structures, microstructure, electrical properties, and polarization characteristics. A multiphase coexistence concerning rhombohedral-orthorhombic and orthorhombic-tetragonal (R-O/O-T) was observed in the ceramics with x = 0.10 and y = 0.15, and then an enhanced piezoelectricity of d33 ˜ 540 pC N-1 and a large strain of ˜0.21% can be attained. More importantly, a larger d33 can be reached when sintered at 1450 °C and polarized at their corresponding phase transition temperatures. We believe that this investigation can benefit the development of barium titanate ceramics.

  14. Giant strain with ultra-low hysteresis and high temperature stability in grain oriented lead-free K₀̣₅Bi₀̣₅TiO₃-BaTiO₃-Na₀̣₅Bi₀̣₅TiO₃ piezoelectric materials

    DOE PAGESBeta

    Maurya, Deepam; Zhou, Yuan; Wang, Yaojin; Yan, Yongke; Li, Jiefang; Viehland, Dwight; Priya, Shashank

    2015-02-26

    We synthesized grain-oriented lead-free piezoelectric materials in (K₀̣₅Bi₀̣₅TiO₃-BaTiO₃-xNa₀̣₅Bi₀̣₅TiO₃ (KBT-BT-NBT) system with high degree of texturing along the [001]c (c-cubic) crystallographic orientation. We demonstrate giant field induced strain (~0.48%) with an ultra-low hysteresis along with enhanced piezoelectric response (d₃₃ ~ 190pC/N) and high temperature stability (~160°C). Transmission electron microscopy (TEM) and piezoresponse force microscopy (PFM) results demonstrate smaller size highly ordered domain structure in grain-oriented specimen relative to the conventional polycrystalline ceramics. The grain oriented specimens exhibited a high degree of non-180° domain switching, in comparison to the randomly axed ones. These results indicate the effective solution to the lead-free piezoelectricmore » materials.« less

  15. Strain engineering effects on electrical properties of lead-free piezoelectric thin films on Si wafers.

    PubMed

    Ohno, Tomoya; Kamai, Yuto; Oda, Yuutaro; Sakamoto, Naonori; Matsuda, Takeshi; Wakiya, Naoki; Suzuki, Hisao

    2014-01-01

    Using radio frequency - magnetron sputtering, calcium-doped barium zirconate titanate ((Ba(0.85)Ca(0.15))(Zr(0.1)Ti(0.9))O(3), BCZT) thin films were deposited on Si wafers with different bottom electrodes. The obtained BCZT thin film on a lanthanum nickel oxide (LNO) electrode had a highly c-axis preferred orientation, while the BCZT thin film on a Pt bottom electrode had (111) preferred orientation. Furthermore, the out-of-plane lattice constant of the BCZT on LNO/Si was 3.4% larger than that of the reported bulk material because of the compressive thermal stress from LNO with a large thermal expansion coefficient. This compressive thermal stress engenders an increase of the Curie temperature. The local piezoelectric response of the BCZT thin film on a LNO/Si structure was measured by piezoresponse force microscope. PMID:25286200

  16. Ultrasonic transducers based on undoped lead-free (K0.5Na0.5)NbO3 ceramics.

    PubMed

    Bah, Micka; Giovannelli, Fabien; Schoenstein, Frederic; Brosseau, Christophe; Deschamps, Jean-Robert; Dorvaux, Frédéric; Haumesser, Lionel; Le Clezio, Emmanuel; Monot-Laffez, Isabelle

    2015-12-01

    Lead zirconate titanate (PZT) ceramics are the dominant piezoelectric elements for non-destructive evaluation (NDE) and ultrasonic transducers devices. However, the presence of lead content may impose the scientific community to develop lead-free ceramics, concerning human health and environmental safety. During the past ten years, many contributions have highlighted the potential properties of complex compositions like LiNbO3, LiTaO3 and LiSbO3 in the lead-free (K0.5Na0.5)NbO3 KNN system. In this context, for the first time, the practical applications and the effectiveness of simply undoped (K0.5Na0.5)NbO3 (KNN) ceramics are investigated. KNN powder is prepared by conventional solid state mixed oxide route. Ceramics of this material are prepared using conventional sintering (CS) and spark plasma sintering (SPS). Thickness coupling factor kt of 44-46%, planar coupling factor kp of 29-45%, relative permittivity at constant strain ε33,r(S) of 125-243 and acoustic impedance Z of 23-30 MRay are obtained for these two kinds of undoped KNN ceramics. Both ceramics are used to build single-element ultrasonic transducers. Relative bandwidth of 49-78% and insertion loss of -27 and -51dB are obtained for SPS and CS transducers, respectively. These results are suitable for use in non-destructive evaluation. The effectiveness of undoped KNN is evaluated using the KLM model, and compared to standard PZT based probe. Finally, chemical aging test of undoped KNN has demonstrated its stability in water. PMID:26117145

  17. Structural dependence of piezoelectric, dielectric and ferroelectric properties of K{sub 0.5}Na{sub 0.5}(Nb{sub 1−2x/5}Cu{sub x})O{sub 3} lead-free ceramics with high Q{sub m}

    SciTech Connect

    Tan, Xiaohui; Department of Mechanical Engineering, The Hong Kong Polytechnic University, Hung Hum, Kowloon ; Fan, Huiqing; Ke, Shanming; Department of Applied Physics and Materials Research Center, The Hong Kong Polytechnic University, Hung Hum, Kowloon ; Zhou, Limin; Mai, Yiu-Wing; Centre for Advanced Materials Technology, School of Aerospace, Mechanical and Mechatronics Engineering J07, The University of Sydney, Sydney, NSW 2006 ; Huang, Haitao

    2012-12-15

    Graphical abstract: Display Omitted Highlights: ► Double hysteresis loops were observed in K{sub 0.5}Na{sub 0.5}(Nb{sub 1−2x/5}Cu{sub x})O{sub 3}. ► Cu substitution caused structural discontinuity in KNNC. ► Dimeric defect complex (Cu{sup ‴}{sub Nb}–V{sub O}··){sup ′} with a dipole moment was formed in KNNC. -- Abstract: (K{sub 0.5}Na{sub 0.5})(Nb{sub 1−2x/5}Cu{sub x})O{sub 3} (abbreviated as KNNC, x = 0–2%) lead-free ceramics were synthetized by the solid state solution method. Pure perovskite phase with orthorhombic symmetry was observed. The evolution of the structure of KNNC was examined by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Raman scattering spectra techniques. Our results revealed that, defect dipoles (Cu{sup ‴}{sub Nb}–V{sub O}··){sup ′} were formed and provided a restoring force to reverse the switched polarization, which resulted in double P–E hysteresis loops in KNNC with Cu doping at x = 0.75% and 1%. However, non-polar defect complex (V{sub O}··–Cu{sup ‴}{sub Nb}–V{sub O}··)· caused a lattice shrinkage and the observed square shaped P–E loops in KNNC ceramics under high doping levels (x > 1%).

  18. Large piezoelectric properties in KNN-based lead-free single crystals grown by a seed-free solid-state crystal growth method

    NASA Astrophysics Data System (ADS)

    Yang, Jie; Zhang, Faqiang; Yang, Qunbao; Liu, Zhifu; Li, Yongxiang; Liu, Yun; Zhang, Qiming

    2016-05-01

    We report lead-free single crystals with a nominal formula of (K0.45Na0.55)0.96Li0.04NbO3 grown using a simple low-cost seed-free solid-state crystal growth method (SFSSCG). The crystals thus prepared can reach maximum dimensions of 6 mm × 5 mm × 2 mm and exhibit a large piezoelectric coefficient d33 of 689 pC/N. Moreover, the effective piezoelectric coefficient d33 * , obtained under a unipolar electric field of 30 kV/cm, can reach 967 pm/V. The large piezoelectric response plus the high Curie temperature (TC) of 432 °C indicate that SFSSCG is an effective approach to synthesize high-performance lead-free piezoelectric single crystals.

  19. Fabrication and characterization of Na0.5K0.5NbO3-CuNb2O6 lead-free step-down piezoelectric transformers

    NASA Astrophysics Data System (ADS)

    Yang, Ming-Ru; Chu, Sheng-Yuan; Chan, I.-Hao; Huang, Sheng-Kai

    2011-08-01

    Lead-free (Na0.5K0.5)NbO3 (NKN) ceramics doped with 1 mol% CuNb2O6 (01CN) ceramics were prepared using the conventional mixed oxide method at a sintering temperature of 1075 °C. NKN + 1 mol% CuTa2O6 (NKN-01CN) ceramics sintered at 1075 °C exhibit excellent "hard" piezoelectric properties of kp = 40%, kt = 45%, and k33 = 57%, with ferroelectric property Ec = 23 kV/cm. The mechanical quality factor (Qm) is extraordinarily high (1933) and the temperature stability is excellent (Temperature coefficient of frequency (TCF) = -154 ppm/°C). The piezoelectric transformer (PT) was fabricated on NKN-01CN lead-free substrates, and the electrical characteristics were investigated. The devices were simplified into an equivalent circuit and analyzed using the MATLAB software package. The simulation results matched the experimental results. By reversing the input and the output, the step-down PT can be easily fabricated using a simple disk-type structure. A maximum efficiency of 93% with a voltage gain of 0.12 was measured, which was in good agreement with the simulation results (a maximum efficiency of 98.7% with a voltage gain of 0.13) for the step-down mode.

  20. Growth and characterization of undoped and Mn doped lead-free piezoelectric NBT–KBT single crystals

    SciTech Connect

    Babu, G. Anandha; Subramaniyan, Raja R.; Bhaumik, Indranil; Ganesamoorthy, S.; Ramasamy, P.; Gupta, P.K.

    2014-05-01

    Highlights: • Single crystals of undoped and Mn doped NKBT crystals are grown by spontaneous nucleation. • Temperature and frequency dependent dielectric constant and loss are measured. • Dielectric constant has increased and the loss has reduced on Mn doped NKBT. • Concentration of oxygen vacancies has been reduced in Mn doped NKBT. • The activation energy for undoped and Mn doped NKBT are calculated. - Abstract: Lead-free piezoelectric single crystals of undoped and 1 wt% Mn doped 0.80 Na{sub 0.5}Bi{sub 0.5}TiO{sub 3}–0.20 K{sub 0.5}Bi{sub 0.5}TiO{sub 3} (NKBT) was grown using self-flux. Powder X-ray diffraction analysis revealed that the grown crystals belong to tetragonal system at room temperature. The lattice strain was calculated from Williamson Hall relation for undoped and Mn doped NKBT crystals. A significant change is observed in dielectric behavior of Mn doped NKBT when compared to undoped sample. The diffuseness increased substantially on Mn doped NKBT which masked the ferroelectric to antiferroelectric transition in the dielectric constant plot. The AC impedance study revealed that the conduction is governed by the singly ionized oxygen vacancy. Further, the decrease in the conductivity on Mn doping suggests that Mn replaces the Bi vacancy, which reduces the oxygen vacancy.

  1. Nonlinear piezoelectricity in Li-modified (K,Na)NbO3 system ceramics

    NASA Astrophysics Data System (ADS)

    Ishii, Keisuke; Tashiro, Shinjiro

    2015-10-01

    The effects of Li substitution on the nonlinear piezoelectricity in lead-free (K,Na)NbO3 (KNN) system ceramics were studied. The nonlinear piezoelectricity causes nonlinear phenomena such as the generation of nonlinear voltages, a change in the resonance frequency, and current jumping under high-power vibration. The magnitude of the nonlinear piezoelectricity was estimated by measuring the third-harmonic voltage generated in samples during constant-current driving. With the increase in the amount of substituted Li, the nonlinear piezoelectricity decreased and became a minimum at the phase boundary composition. The nonlinear piezoelectric coefficient at the phase boundary composition was less than one-tenth of the value in the nonsubstituted KNN ceramic.

  2. Preparation and characterization of Sr0.5Ba0.5Nb2O6 glass-ceramic on piezoelectric properties

    NASA Astrophysics Data System (ADS)

    Shan, Jiang; Xuan-Ming, Wang; Jia-Yu, Li; Yong, Zhang; Tao, Zheng; Jing-Wen, Lv

    2016-03-01

    We studied the influence of heat treatment time on the optical, thermal, electrical, and mechanical properties of strontium barium niobate (Sr1-xBaxNb2O6 hereafter SBN) piezoelectric glass-ceramics with tungsten bronze-type structure, which have good piezoelectric properties and are important lead-free piezoelectric materials. We found that the best heat treatment time is 4 h. The properties of the prepared materials are better than that of SBN ceramics and the glass-ceramic growth is faster than the SBN crystal when the heat treatment time of the SBN piezoelectric glass-ceramic is controlled, reducing the preparation costs greatly.

  3. Dielectric, ferroelectric, and piezoelectric properties of the lead-free (1-x)(Na0.5Bi0.5)TiO3-xBiAlO3 solid solution

    NASA Astrophysics Data System (ADS)

    Yu, Huichun; Ye, Zuo-Guang

    2008-09-01

    Lead-free piezoelectric ceramics derived from the solid solution of (1-x)(Na0.5Bi0.5)TiO3-xBiAlO3 (NBT-BA) (x =0-0.10) have been synthesized by solid state reactions. A pure perovskite phase was formed for x ≤0.08. The temperature dependence of dielectric constant indicates an increased broadness of the dielectric peak as the amount of BA increases. The large dielectric loss of NBT ceramics at low frequency and high temperature has been significantly reduced by the substitution of BA. The high coercive field is decreased and ferroelectric hysteresis loops were displayed at room temperature. The NBT-BA ceramics exhibit improved ferroelectric and piezoelectric properties compared to pure NBT ceramics, with Pr=52 μC/cm2, Ec=44 kV/cm, d33=130 pC/N, and kp=0.23 for 0.92NBT-0.08BA.

  4. Electrical properties of (1−x)(Bi{sub 0.5}Na{sub 0.5})TiO{sub 3}–xKNbO{sub 3} lead-free ceramics

    SciTech Connect

    Jiang, Xijie; Wang, Baoyin; Luo, Laihui; Li, Weiping; Zhou, Jun; Chen, Hongbing

    2014-05-01

    In this investigation, a simple compound (1−x)(Bi{sub 0.5}Na{sub 0.5})TiO{sub 3}–xKNbO{sub 3} (BNT–xKN, x=0–0.08) lead-free ceramics were synthesized successfully by conventional solid state reaction method. The piezoelectric, dielectric and ferroelectric characteristics of the ceramics were investigated and discussed. The results shows that moderate KN addition can enhance the piezoelectric response without an obvious decline of ferroelectric properties. The largest piezoelectric response is obtained in BNT–0.05KN, whereas largest electric-field-induced strain is obtained in BNT–0.06KN. An effective d{sub 33}{sup eff} of ∼400 pC/N calculated from electric-field-induced strain is obtained in BNT–0.06KN. The present investigation demonstrates that addition KN effectively reduces the depolarization temperature of the BNT–xKN ceramics. The electrical properties of the ceramics are tightly related to their depolarization temperature. - Graphical abstract: Unipolar electric-field-induced strain for the BNT–xKN ceramics. A maximum strain of 0.28% is achieved with a low field in BNT–0.06KN. - Highlights: • Moderate KNbO{sub 3} addition enhances the piezoelectric properties of the ceramics. • A maximum strain of 0.28% is achieved with a low field. • A large piezoelectric response is achieved in 0.95(Bi{sub 0.5}Na{sub 0.5})TiO{sub 3}–0.05KNbO{sub 3}. • The electrical properties are tightly related to the depolarization temperature T{sub d}.

  5. Effects of Cr2O3 doping on the microstructure and electrical properties of (Ba,Ca)(Zr,Ti)O3 lead-free ceramics

    NASA Astrophysics Data System (ADS)

    Xia, Xiang; Jiang, Xiangping; Chen, Chao; Jiang, Xingan; Tu, Na; Chen, Yunjing

    2016-04-01

    Lead-free ceramics (Ba0.85Ca0.15)(Zr0.9Ti0.1)O3-x wt.%Cr2O3 (BCZT-xCr) were prepared via the conventional solid-state reaction method. The microstructure and electrical properties of BCZT-xCr samples were systematically studied. XRD and Raman results showed that all samples possessed a single phased perovskite structure and were close to the morphotropic phase boundary (MPB). With the increase of the Cr content, the rhombohedral-tetragonal phase transition temperature (T R-T) increases slightly, and the Curie temperature (T C) shifts towards the low temperature side. XPS analysis reveals that Cr3+ and Cr5+ ions co-existed in Cr-doped BCZT ceramics, indicating the different impact on the electrical properties from Cr ions as "acceptor" or "donor". For the x = 0.1 sample, relative high piezoelectric constants d 33 (~316 pC/N) as well as high Q m (~554) and low tanδ (~0.8%) were obtained. In addition, the AC conductivity was also investigated. Hopping charge was considered as the main conduction mechanism at low temperature. As the temperature increases, small polarons and oxygen vacancies conduction played important roles.

  6. A study on (K, Na) NbO3 based multilayer piezoelectric ceramics micro speaker

    NASA Astrophysics Data System (ADS)

    Gao, Renlong; Chu, Xiangcheng; Huan, Yu; Sun, Yiming; Liu, Jiayi; Wang, Xiaohui; Li, Longtu

    2014-10-01

    A flat panel micro speaker was fabricated from (K, Na) NbO3 (KNN)-based multilayer piezoelectric ceramics by a tape casting and cofiring process using Ag-Pd alloys as an inner electrode. The interface between ceramic and electrode was investigated by scanning electron microscope (SEM) and transmission electron microscope (TEM). The acoustic response was characterized by a standard audio test system. We found that the micro speaker with dimensions of 23 × 27 × 0.6 mm3, using three layers of 30 μm thickness KNN-based ceramic, has a high average sound pressure level (SPL) of 87 dB, between 100 Hz-20 kHz under five voltage. This result was even better than that of lead zirconate titanate (PZT)-based ceramics under the same conditions. The experimental results show that the KNN-based multilayer ceramics could be used as lead free piezoelectric micro speakers.

  7. Mechanical confinement for improved energy storage density in BNT-BT-KNN lead-free ceramic capacitors

    NASA Astrophysics Data System (ADS)

    Chauhan, Aditya; Patel, Satyanarayan; Vaish, Rahul

    2014-08-01

    With the advent of modern power electronics, embedded circuits and non-conventional energy harvesting, the need for high performance capacitors is bound to become indispensible. The current state-of-art employs ferroelectric ceramics and linear dielectrics for solid state capacitance. However, lead-free ferroelectric ceramics propose to offer significant improvement in the field of electrical energy storage owing to their high discharge efficiency and energy storage density. In this regards, the authors have investigated the effects of compressive stress as a means of improving the energy storage density of lead-free ferroelectric ceramics. The energy storage density of 0.91(Bi0.5Na0.5)TiO3-0.07BaTiO3-0.02(K0.5Na0.5)NbO3 ferroelectric bulk ceramic was analyzed as a function of varying levels of compressive stress and operational temperature .It was observed that a peak energy density of 387 mJ.cm-3 was obtained at 100 MPa applied stress (25oC). While a maximum energy density of 568 mJ.cm-3 was obtained for the same stress at 80oC. These values are indicative of a significant, 25% and 84%, improvement in the value of stored energy compared to an unloaded material. Additionally, material's discharge efficiency has also been discussed as a function of operational parameters. The observed phenomenon has been explained on the basis of field induced structural transition and competitive domain switching theory.

  8. Effects of Hafnium Substitution on Dielectric and Electromechanical Properties of Lead-free Bi0.5(Na0.78K0.22)0.5(Ti1-xHfx)O3 Ceramics

    NASA Astrophysics Data System (ADS)

    Hussain, Ali; Ahn, Chang Won; Ullah, Aman; Lee, Jae Shin; Kim, Ill Won

    2010-04-01

    Lead-free piezoelectric Bi0.5(Na0.78K0.22)0.5(Ti1-xHfx)O3 ceramics (abbreviated as BNKTH-100x, x=0-0.05) were prepared by the conventional solid-state reaction method. The effects of Hf substitution on the crystal structure and electromechanical properties were investigated. The X-ray diffraction patterns of the BNKTH-100x ceramics revealed a single-phase perovskite structure with no evidence of secondary phases. The temperature-dependent dielectric curves of the BNKTH-100x ceramics were found to broaden with increasing Hf concentration. The electric-field-induced strain of the BNKTH-100x ceramics increased up to x=0.03 and then decreased. An enhanced electric-field-induced strain of 0.38% is observed for the BNKTH-3 ceramic. The corresponding normalized strain (Smax/Emax=d33*) for this composition was 475 pm/V at an applied electric field of 80 kV/cm. The BNKTH-3 ceramic can be considered as a promising candidate material for lead-free electromechanical applications.

  9. Effects of Hafnium Substitution on Dielectric and Electromechanical Properties of Lead-free Bi0.5(Na0.78K0.22)0.5(Ti1-xHfx)O3 Ceramics

    NASA Astrophysics Data System (ADS)

    Ali Hussain,; Chang Won Ahn,; Aman Ullah,; Jae Shin Lee,; Ill Won Kim,

    2010-04-01

    Lead-free piezoelectric Bi0.5(Na0.78K0.22)0.5(Ti1-xHfx)O3 ceramics (abbreviated as BNKTH-100x, x=0--0.05) were prepared by the conventional solid-state reaction method. The effects of Hf substitution on the crystal structure and electromechanical properties were investigated. The X-ray diffraction patterns of the BNKTH-100x ceramics revealed a single-phase perovskite structure with no evidence of secondary phases. The temperature-dependent dielectric curves of the BNKTH-100x ceramics were found to broaden with increasing Hf concentration. The electric-field-induced strain of the BNKTH-100x ceramics increased up to x=0.03 and then decreased. An enhanced electric-field-induced strain of 0.38% is observed for the BNKTH-3 ceramic. The corresponding normalized strain (Smax/Emax=d33*) for this composition was 475 pm/V at an applied electric field of 80 kV/cm. The BNKTH-3 ceramic can be considered as a promising candidate material for lead-free electromechanical applications.

  10. Anomalous change in leakage and displacement currents after electrical poling on lead-free ferroelectric ceramics

    NASA Astrophysics Data System (ADS)

    Borkar, Hitesh; Tomar, M.; Gupta, Vinay; Scott, J. F.; Kumar, Ashok

    2015-09-01

    We report the polarization, displacement current, and leakage current behavior of a trivalent nonpolar cation (Al3+) substituted lead free ferroelectric (Na0.46Bi0.46-xAlxBa0.08)TiO3 (NBAT-BT) (x = 0, 0.05, 0.07 and 0.10) electroceramics with tetragonal phase and P4 mm space group symmetry. Almost, three orders of magnitude decrease in leakage current were observed under electrical poling, which significantly improves microstructure, polarization, and displacement current. Effective poling neutralizes the domain pinning, traps charges at grain boundaries and fills oxygen vacancies with free charge carriers in matrix, thus saturated macroscopic polarization in contrast to that in unpoled samples. E-poling changes "bananas" type polarization loops to real ferroelectric loops.

  11. Nanoscale mapping of heterogeneity of the polarization reversal in lead-free relaxor-ferroelectric ceramic composites

    NASA Astrophysics Data System (ADS)

    Gobeljic, D.; Shvartsman, V. V.; Belianinov, A.; Okatan, B.; Jesse, S.; Kalinin, S. V.; Groh, C.; Rödel, J.; Lupascu, D. C.

    2016-01-01

    Relaxor/ferroelectric ceramic/ceramic composites have shown to be promising in generating large electromechanical strain at moderate electric fields. Nonetheless, the mechanisms of polarization and strain coupling between grains of different nature in the composites remain unclear. To rationalize the coupling mechanisms we performed advanced piezoresponse force microscopy (PFM) studies of 0.92BNT-0.06BT-0.02KNN/0.93BNT-0.07BT (ergodic/non-ergodic relaxor) composites. PFM is able to distinguish grains of different phases by characteristic domain patterns. Polarization switching has been probed locally, on a sub-grain scale. k-Means clustering analysis applied to arrays of local hysteresis loops reveals variations of polarization switching characteristics between the ergodic and non-ergodic relaxor grains. We report a different set of switching parameters for grains in the composites as opposed to the pure phase samples. Our results confirm ceramic/ceramic composites to be a viable approach to tailor the piezoelectric properties and optimize the macroscopic electromechanical characteristics.Relaxor/ferroelectric ceramic/ceramic composites have shown to be promising in generating large electromechanical strain at moderate electric fields. Nonetheless, the mechanisms of polarization and strain coupling between grains of different nature in the composites remain unclear. To rationalize the coupling mechanisms we performed advanced piezoresponse force microscopy (PFM) studies of 0.92BNT-0.06BT-0.02KNN/0.93BNT-0.07BT (ergodic/non-ergodic relaxor) composites. PFM is able to distinguish grains of different phases by characteristic domain patterns. Polarization switching has been probed locally, on a sub-grain scale. k-Means clustering analysis applied to arrays of local hysteresis loops reveals variations of polarization switching characteristics between the ergodic and non-ergodic relaxor grains. We report a different set of switching parameters for grains in the composites as opposed to the pure phase samples. Our results confirm ceramic/ceramic composites to be a viable approach to tailor the piezoelectric properties and optimize the macroscopic electromechanical characteristics. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr05032d

  12. Wide phase boundary zone, piezoelectric properties, and stability in 0.97(K0.4Na0.6)(Nb1-xSbx)O3-0.03Bi0.5Li0.5ZrO3 lead-free ceramics.

    PubMed

    Zheng, Ting; Wu, Jiagang; Cheng, Xiaojing; Wang, Xiaopeng; Zhang, Binyu; Xiao, Dingquan; Zhu, Jianguo; Lou, Xiaojie

    2014-07-01

    In this work, the rhombohedral (R) and tetragonal (T) phase boundary of the 0.97(K0.4Na0.6)(Nb1-xSbx)O3-0.03Bi0.5Li0.5ZrO3 piezoceramics has been attained in a wide composition range of 0.035 ? x ? 0.08, and the Sb(5+) could simultaneously shrink its TR-O and TO-T. A giant d33 of 380-405 pC N(-1) and a TC of 200-292 C have been observed in the ceramics with the coexistence of both R and T phases. In addition, the ceramics with 0.035 ? x ? 0.08 also show a good thermal stability of the d33, and an enhanced temperature stability of ferroelectricity could be observed in the ceramic with x = 0.035. As a result, adding the optimum antimony content is an efficient way to promote the electrical properties of potassium-sodium niobate ceramics with the R-T phase boundary. PMID:24848676

  13. Giant strain with ultra-low hysteresis and high temperature stability in grain oriented lead-free K₀̣₅Bi₀̣₅TiO₃-BaTiO₃-Na₀̣₅Bi₀̣₅TiO₃ piezoelectric materials

    SciTech Connect

    Maurya, Deepam; Zhou, Yuan; Wang, Yaojin; Yan, Yongke; Li, Jiefang; Viehland, Dwight; Priya, Shashank

    2015-02-26

    We synthesized grain-oriented lead-free piezoelectric materials in (K₀̣₅Bi₀̣₅TiO₃-BaTiO₃-xNa₀̣₅Bi₀̣₅TiO₃ (KBT-BT-NBT) system with high degree of texturing along the [001]c (c-cubic) crystallographic orientation. We demonstrate giant field induced strain (~0.48%) with an ultra-low hysteresis along with enhanced piezoelectric response (d₃₃ ~ 190pC/N) and high temperature stability (~160°C). Transmission electron microscopy (TEM) and piezoresponse force microscopy (PFM) results demonstrate smaller size highly ordered domain structure in grain-oriented specimen relative to the conventional polycrystalline ceramics. The grain oriented specimens exhibited a high degree of non-180° domain switching, in comparison to the randomly axed ones. These results indicate the effective solution to the lead-free piezoelectric materials.

  14. Giant strain with ultra-low hysteresis and high temperature stability in grain oriented lead-free K0.5Bi0.5TiO3-BaTiO3-Na0.5Bi0.5TiO3 piezoelectric materials

    PubMed Central

    Maurya, Deepam; Zhou, Yuan; Wang, Yaojin; Yan, Yongke; Li, Jiefang; Viehland, Dwight; Priya, Shashank

    2015-01-01

    We synthesized grain-oriented lead-free piezoelectric materials in (K0.5Bi0.5TiO3-BaTiO3-xNa0.5Bi0.5TiO3 (KBT-BT-NBT) system with high degree of texturing along the [001]c (c-cubic) crystallographic orientation. We demonstrate giant field induced strain (~0.48%) with an ultra-low hysteresis along with enhanced piezoelectric response (d33 ~ 190pC/N) and high temperature stability (~160°C). Transmission electron microscopy (TEM) and piezoresponse force microscopy (PFM) results demonstrate smaller size highly ordered domain structure in grain-oriented specimen relative to the conventional polycrystalline ceramics. The grain oriented specimens exhibited a high degree of non-180° domain switching, in comparison to the randomly axed ones. These results indicate the effective solution to the lead-free piezoelectric materials. PMID:25716551

  15. Giant strain with ultra-low hysteresis and high temperature stability in grain oriented lead-free K0.5Bi0.5TiO3-BaTiO3-Na0.5Bi0.5TiO3 piezoelectric materials.

    PubMed

    Maurya, Deepam; Zhou, Yuan; Wang, Yaojin; Yan, Yongke; Li, Jiefang; Viehland, Dwight; Priya, Shashank

    2015-01-01

    We synthesized grain-oriented lead-free piezoelectric materials in (K0.5Bi0.5TiO3-BaTiO3-xNa0.5Bi0.5TiO3 (KBT-BT-NBT) system with high degree of texturing along the [001]c (c-cubic) crystallographic orientation. We demonstrate giant field induced strain (~0.48%) with an ultra-low hysteresis along with enhanced piezoelectric response (d33 ~ 190pC/N) and high temperature stability (~160C). Transmission electron microscopy (TEM) and piezoresponse force microscopy (PFM) results demonstrate smaller size highly ordered domain structure in grain-oriented specimen relative to the conventional polycrystalline ceramics. The grain oriented specimens exhibited a high degree of non-180 domain switching, in comparison to the randomly axed ones. These results indicate the effective solution to the lead-free piezoelectric materials. PMID:25716551

  16. Giant strain with ultra-low hysteresis and high temperature stability in grain oriented lead-free K0.5Bi0.5TiO3-BaTiO3-Na0.5Bi0.5TiO3 piezoelectric materials

    NASA Astrophysics Data System (ADS)

    Maurya, Deepam; Zhou, Yuan; Wang, Yaojin; Yan, Yongke; Li, Jiefang; Viehland, Dwight; Priya, Shashank

    2015-02-01

    We synthesized grain-oriented lead-free piezoelectric materials in (K0.5Bi0.5TiO3-BaTiO3-xNa0.5Bi0.5TiO3 (KBT-BT-NBT) system with high degree of texturing along the [001]c (c-cubic) crystallographic orientation. We demonstrate giant field induced strain (~0.48%) with an ultra-low hysteresis along with enhanced piezoelectric response (d33 ~ 190pC/N) and high temperature stability (~160C). Transmission electron microscopy (TEM) and piezoresponse force microscopy (PFM) results demonstrate smaller size highly ordered domain structure in grain-oriented specimen relative to the conventional polycrystalline ceramics. The grain oriented specimens exhibited a high degree of non-180 domain switching, in comparison to the randomly axed ones. These results indicate the effective solution to the lead-free piezoelectric materials.

  17. Effect of B-site isovalent doping on electrical and ferroelectric properties of lead free bismuth titanate ceramics

    NASA Astrophysics Data System (ADS)

    Subohi, Oroosa; Kumar, G. S.; Malik, M. M.; Kurchania, Rajnish

    2016-06-01

    In the present work, zirconium modified bismuth titanate ceramics have been studied as potential lead-free ferroelectric materials over a broad temperature range (RT - 800 °C). Polycrystalline samples of Bi4Ti3-xZrxO12 (x=0.2, 0.4, 0.6) (BZrT) with high electrical resistivity were prepared using the solution combustion technique. The effect of Zr doping on the crystalline structure, ferroelectric properties and electrical conduction characteristics of BZrT ceramics were explored. Addition of zirconium to bismuth titanate enhances its dielectric constant and reduces the loss factor as it introduces orthorhombic distortion in bismuth titanate lattice which is exhibited by the growth along (00_10) lattice plane. Activation energy due to relaxation is found to be greater than that due to conduction thus confirming that electrical conduction in these ceramics is not due to relaxation of dipoles. Remanent polarization of the doped samples increases as the Zirconium content increases.

  18. Nanoscale mapping of heterogeneity of the polarization reversal in lead-free relaxor-ferroelectric ceramic composites.

    PubMed

    Gobeljic, D; Shvartsman, V V; Belianinov, A; Okatan, B; Jesse, S; Kalinin, S V; Groh, C; Rödel, J; Lupascu, D C

    2016-01-21

    Relaxor/ferroelectric ceramic/ceramic composites have shown to be promising in generating large electromechanical strain at moderate electric fields. Nonetheless, the mechanisms of polarization and strain coupling between grains of different nature in the composites remain unclear. To rationalize the coupling mechanisms we performed advanced piezoresponse force microscopy (PFM) studies of 0.92BNT-0.06BT-0.02KNN/0.93BNT-0.07BT (ergodic/non-ergodic relaxor) composites. PFM is able to distinguish grains of different phases by characteristic domain patterns. Polarization switching has been probed locally, on a sub-grain scale. k-Means clustering analysis applied to arrays of local hysteresis loops reveals variations of polarization switching characteristics between the ergodic and non-ergodic relaxor grains. We report a different set of switching parameters for grains in the composites as opposed to the pure phase samples. Our results confirm ceramic/ceramic composites to be a viable approach to tailor the piezoelectric properties and optimize the macroscopic electromechanical characteristics. PMID:26731664

  19. Structure, dielectric tunability, thermal stability and diffuse phase transition behavior of lead free BZT-BCT ceramic capacitors

    NASA Astrophysics Data System (ADS)

    Sreenivas Puli, Venkata; Pradhan, Dhiren K.; Pérez, W.; Katiyar, R. S.

    2013-03-01

    This paper reports the development of a lead free {Ba(Zr0.2Ti0.8)O3}(1-x){(Ba0.7Ca0.3)TiO3}x - x=0.10, 0.15 and 0.20 - BZT-BCT ceramic solid solution system prepared using a solid-state reaction technique. The evolution of the Raman spectra with temperature was used to study the variation of the basic phase transition of BaTiO3 in these compositions. The phase transition temperature on heating was found to decrease to 310 K, 300 K, and 300 K, respectively, with increasing Ca content on BCT end and decreasing Zr content on BZT end of lead free pseudobinary ferroelectric BZT-BCT system. Tetragonal and rhombohedral phase coexistence is observed at room temperature from X-ray diffraction (XRD) spectra. Rhombohedral phase is identified between the 83 K and 273 K from temperature dependent Raman studies. Raman results are in excellent agreement with those obtained from temperature dependent dielectric measurements. Bulk ceramic BZT-BCT materials have shown interesting temperature dependent dielectric properties and as well as higher values of room temperature dielectric constant ˜7800, 8400, 5200, dielectric tunability ˜82%, figure of merit (FOM) ˜93.71 % with low dielectric loss (tan δ) ˜0.015 to 0.024 and good thermal stability at high sintering temperature (1600 °C); they might be one of the strong candidates for dielectric tunable capacitor applications in an environmentally protective atmosphere.

  20. Determination of crystallographic orientation of lead-free piezoelectric (K,Na)NbO3 epitaxial thin films grown on SrTiO3 (100) surfaces

    NASA Astrophysics Data System (ADS)

    Yu, Qi; Zhu, Fang-Yuan; Cheng, Li-Qian; Wang, Ke; Li, Jing-Feng

    2014-03-01

    Crystallographic structure of sol-gel-processed lead-free (K,Na)NbO3 (KNN) epitaxial films on [100]-cut SrTiO3 single-crystalline substrates was investigated for a deeper understanding of its piezoelectric response. Lattice parameter measurement by high-resolution X-ray diffraction and transmission electron microscopy revealed that the orthorhombic KNN films on SrTiO3 (100) surfaces are [010] oriented (b-axis-oriented) rather than commonly identified c-axis orientation. Based on the crystallographic orientation and corresponding ferroelectric domain structure investigated by piezoresponse force microscopy, the superior piezoelectric property along b-axis of epitaxial KNN films than other orientations can be explained.

  1. Doping effects of Li-Sb content on the structure and electrical properties of [(Na{sub 0.5}K{sub 0.5}){sub 1-x}(Li){sub x}(Sb){sub x}(Nb){sub 1} {sub -x}O{sub 3}] lead-free piezoelectric ceramics

    SciTech Connect

    Rani, Rashmi; Sharma, Seema; Rai, Radheshyam; Kholkin, Andrei L.

    2012-02-15

    Highlights: Black-Right-Pointing-Pointer [Na{sub 0.5}K{sub 0.5}]{sub 1-x}(Li){sub x}(Sb){sub x}(Nb){sub 1-x}O{sub 3} were prepared by solid-state reaction method. Black-Right-Pointing-Pointer XRD analysis of the powder suggests the formation of a single-phase material. Black-Right-Pointing-Pointer The crystal structure changes from orthorhombic to tetragonal with increase in x. Black-Right-Pointing-Pointer Dielectric studies show a diffuse phase transition at 100 Degree-Sign C and 330 Degree-Sign C. Black-Right-Pointing-Pointer The composition x = 0.050 shows maximum remanent polarization (Pr {approx} 0.66 C m{sup -2}). -- Abstract: Ceramic samples of [Na{sub 0.5}K{sub 0.5}]{sub 1-x}(Li){sub x}(Sb){sub x}(Nb){sub 1-x}O{sub 3} (NKNLS) (x = 0.04-0.06) were prepared by high temperature solid-state reaction method. X-ray diffraction analysis of the powder samples suggests the formation of a single-phase material with transformation from orthorhombic to tetragonal crystal structure with increase in Sb content. Dielectric studies show a diffuse phase transition about 100 Degree-Sign C and another phase ferroelectric-paraelectric transition at 330 Degree-Sign C. Polarization vs. electric field (P-E) hysteresis studies show maximum remanent polarization (Pr {approx} 0.66 C m{sup -2}) for composition x = 0.05. AC conductivity in the compound increases with increase in temperature which may be attributed due to oxygen vacancies and show negative temperature coefficient of resistance (NTCR) effect.

  2. Electromechanical characteristics of piezoelectric ceramic transformers in radial vibration composed of concentric piezoelectric ceramic disk and ring

    NASA Astrophysics Data System (ADS)

    Lin, Shuyu; Hu, Jing; Fu, Zhiqiang

    2013-04-01

    A new type of piezoelectric ceramic transformer in radial vibration is presented. The piezoelectric transformer consists of a pairing of a concentric piezoelectric ceramic circular disk and ring. The inner piezoelectric ceramic disk is axially polarized and the outer piezoelectric ring is radially polarized. Based on the plane stress theory, the exact analytical theory for the piezoelectric transformer is developed and its electromechanical equivalent circuit is introduced. The resonance/anti-resonance frequency equations of the transformer are obtained and the relationship between the resonance/anti-resonance frequency, the effective electromechanical coupling coefficient and the geometrical dimensions of the piezoelectric transformer is analyzed. The dependency of the voltage transformation ratio on the frequency is obtained. To verify the analytical theory, a numerical method is used to simulate the electromechanical characteristics of the piezoelectric transformer. It is shown that the analytical resonance/anti-resonance frequencies are in good agreement with the numerical results.

  3. Piezoelectric nonlinearity and frequency dispersion of the direct piezoelectric response of BiFeO3 ceramics

    NASA Astrophysics Data System (ADS)

    Rojac, Tadej; Bencan, Andreja; Drazic, Goran; Kosec, Marija; Damjanovic, Dragan

    2012-09-01

    We report on the frequency and stress dependence of the direct piezoelectric d33 coefficient in BiFeO3 ceramics. The measurements reveal considerable piezoelectric nonlinearity, i.e., dependence of d33 on the amplitude of the dynamic stress. The nonlinear response suggests a large irreversible contribution of non-180° domain walls to the piezoelectric response of the ferrite, which, at present measurement conditions, reached a maximum of 38% of the total measured d33. In agreement with this interpretation, both types of non-180° domain walls, characteristic for the rhombohedral BiFeO3, i.e., 71° and 109°, were identified in the poled ceramics using transmission electron microscopy. In support to the link between nonlinearity and non-180° domain-wall contribution, we found a correlation between nonlinearity and processes leading to depinning of domain walls from defects, such as quenching from above the Curie temperature and high-temperature sintering. In addition, the nonlinear piezoelectric response of BiFeO3 showed a frequency dependence that is qualitatively different from that measured in other nonlinear ferroelectric ceramics, such as "soft" (donor-doped) Pb(Zr,Ti)O3 (PZT), i.e., in the case of the BiFeO3 large nonlinearities were observed only at low field frequencies (<0.1 Hz); possible origins of this dispersion are discussed. Finally, we show that, once released from pinning centers, the domain walls can contribute extensively to the electromechanical response of BiFeO3; in fact, the extrinsic domain-wall contribution is relatively as large as in Pb-based ferroelectric ceramics with morphotropic phase boundary (MPB) composition, such as PZT. This finding might be important in the search of new lead-free MPB compositions based on BiFeO3 as it suggests that such compositions might also exhibit large extrinsic domain-wall contribution to the piezoelectric response.

  4. Lead-free ZnSnO3/MWCNTs-based self-poled flexible hybrid nanogenerator for piezoelectric power generation

    NASA Astrophysics Data System (ADS)

    Mehebub Alam, Md; Ghosh, Sujoy Kumar; Sultana, Ayesha; Mandal, Dipankar

    2015-04-01

    A high-performance flexible piezoelectric hybrid nanogenerator (HNG) based on lead-free perovskite zinc stannate (ZnSnO3) nanocubes and polydimethylsiloxane (PDMS) composite with multiwall carbon nanotubes (MWCNTs) as supplement filling material is demonstrated. Even without any electrical poling treatment, the HNG possesses an open-circuit voltage of 40 V and a short-circuit current of 0.4 μA, respectively, under repeated human finger impact. It has been demonstrated that the output volume power density of 10.8 μW cm-3 from a HNG can drive several colour light emitting diodes (LEDs) and a charge capacitor that powers up a calculator, indicating an effective means of energy harvesting power source with high energy conversion efficiency (˜1.17%) for portable electronic devices.

  5. Lead-free ZnSnO3/MWCNTs-based self-poled flexible hybrid nanogenerator for piezoelectric power generation.

    PubMed

    Alam, Md Mehebub; Ghosh, Sujoy Kumar; Sultana, Ayesha; Mandal, Dipankar

    2015-04-24

    A high-performance flexible piezoelectric hybrid nanogenerator (HNG) based on lead-free perovskite zinc stannate (ZnSnO3) nanocubes and polydimethylsiloxane (PDMS) composite with multiwall carbon nanotubes (MWCNTs) as supplement filling material is demonstrated. Even without any electrical poling treatment, the HNG possesses an open-circuit voltage of 40 V and a short-circuit current of 0.4 μA, respectively, under repeated human finger impact. It has been demonstrated that the output volume power density of 10.8 μW cm(-3) from a HNG can drive several colour light emitting diodes (LEDs) and a charge capacitor that powers up a calculator, indicating an effective means of energy harvesting power source with high energy conversion efficiency (∼1.17%) for portable electronic devices. PMID:25827201

  6. A new Bi{sub 0.5}Na{sub 0.5}TiO{sub 3} based lead-free piezoelectric system with calculated end-member Bi(Zn{sub 0.5}Hf{sub 0.5})O{sub 3}

    SciTech Connect

    Liu, Feng; Wahyudi, Olivia; Li, Yongxiang

    2014-03-21

    The phase structure, dielectric and piezoelectric properties of a new lead-free piezoelectric system (1 − x)Bi{sub 0.5}Na{sub 0.5}TiO{sub 3}–xBi(Zn{sub 0.5}Hf{sub 0.5})O{sub 3} [(1 − x)BNT–xBZH, x = 0, 0.01, 0.02, 0.03, and 0.04] were investigated. The structure of Bi(Zn{sub 0.5}Hf{sub 0.5})O{sub 3} was calculated using first-principles method and (1 − x)BNT–xBZH ceramics were fabricated by conventional solid-state process. At room temperature, a morphotropic phase boundary (MPB) from rhombohedral to pseudocubic is identified near x = 0.02 by the analysis of X-ray diffraction patterns. The ceramics with MPB near room temperature exhibit excellent electrical properties: the Curie temperature, maximum polarization, remnant polarization, and coercive field are 340 °C, 56.3 μC/cm{sup 2}, 43.5 μC/cm{sup 2}, and 5.4 kV/mm, respectively, while the maximum positive bipolar strain and piezoelectric coefficient are 0.09% and 92 pC/N, respectively. In addition, a linear relationship between the MPB phase boundary composition and the calculated tetragonality of non-BNT end-member was demonstrated. Thus, this study not only shows a new BNT-based lead-free piezoelectric system but also suggest a new way to predict the composition at MPB a priori when designing new lead-free piezoelectric system.

  7. Relaxor ferroelectricity and electric-field-driven structural transformation in the giant lead-free piezoelectric (Ba ,Ca ) (Ti ,Zr ) O3

    NASA Astrophysics Data System (ADS)

    Brajesh, Kumar; Tanwar, Khagesh; Abebe, Mulualem; Ranjan, Rajeev

    2015-12-01

    There is great interest in lead-free (B a0.85C a0.15 ) (T i0.90Z r0.10 ) O3 (15/10BCTZ) because of its exceptionally large piezoelectric response [Liu and Ren, Phys. Rev. Lett. 103, 257602 (2009), 10.1103/PhysRevLett.103.257602]. In this paper, we have analyzed the nature of: (i) crystallographic phase coexistence at room temperature, (ii) temperature- and field-induced phase transformation to throw light on the atomistic mechanisms associated with the large piezoelectric response of this system. A detailed temperature-dependent dielectric and lattice thermal expansion study proved that the system exhibits a weak dielectric relaxation, characteristic of a relaxor ferroelectric material on the verge of exhibiting a normal ferroelectric-paraelectric transformation. Careful structural analysis revealed that a ferroelectric state at room temperature is composed of three phase coexistences, tetragonal (P 4 m m )+ orthorhombic(Amm 2 )+rhombohedral(R 3 m ) . We also demonstrate that the giant piezoresponse is associated with a significant fraction of the tetragonal phase transforming to rhombohedral. It is argued that the polar nanoregions associated with relaxor ferroelectricity amplify the piezoresponse by providing an additional degree of intrinsic structural inhomogeneity to the system.

  8. Origin of giant piezoelectric effect in lead-free K1-xNaxTa1-yNbyO3 single crystals.

    PubMed

    Tian, Hao; Meng, Xiangda; Hu, Chengpeng; Tan, Peng; Cao, Xilong; Shi, Guang; Zhou, Zhongxiang; Zhang, Rui

    2016-01-01

    A series of high-quality, large-sized (maximum size of 16 × 16 × 32 mm(3)) K1-xNaxTa1-yNbyO3 (x = 0.61, 0.64, and 0.70 and corresponding y = 0.58, 0.60, and 0.63) single crystals were grown using the top-seed solution growth method. The segregation of the crystals, which allowed for precise control of the individual components of the crystals during growth, was investigated. The obtained crystals exhibited excellent properties without being annealed, including a low dielectric loss (0.006), a saturated hysteresis loop, a giant piezoelectric coefficient d33 (d33 = 416 pC/N, determined by the resonance method and d33(*) = 480 pC/N, measured using a piezo-d33 meter), and a large electromechanical coupling factor, k33 (k33 = 83.6%), which was comparable to that of lead zirconate titanate. The reason the piezoelectric coefficient d33 of K0.39Na0.61Ta0.42Nb0.58O3 was larger than those of the other two crystals grown was elucidated through first-principles calculations. The obtained results indicated that K1-xNaxTa1-yNbyO3 crystals can be used as a high-quality, lead-free piezoelectric material. PMID:27160075

  9. Origin of giant piezoelectric effect in lead-free K1−xNaxTa1−yNbyO3 single crystals

    PubMed Central

    Tian, Hao; Meng, Xiangda; Hu, Chengpeng; Tan, Peng; Cao, Xilong; Shi, Guang; Zhou, Zhongxiang; Zhang, Rui

    2016-01-01

    A series of high-quality, large-sized (maximum size of 16 × 16 × 32 mm3) K1−xNaxTa1−yNbyO3 (x = 0.61, 0.64, and 0.70 and corresponding y = 0.58, 0.60, and 0.63) single crystals were grown using the top-seed solution growth method. The segregation of the crystals, which allowed for precise control of the individual components of the crystals during growth, was investigated. The obtained crystals exhibited excellent properties without being annealed, including a low dielectric loss (0.006), a saturated hysteresis loop, a giant piezoelectric coefficient d33 (d33 = 416 pC/N, determined by the resonance method and d33* = 480 pC/N, measured using a piezo-d33 meter), and a large electromechanical coupling factor, k33 (k33 = 83.6%), which was comparable to that of lead zirconate titanate. The reason the piezoelectric coefficient d33 of K0.39Na0.61Ta0.42Nb0.58O3 was larger than those of the other two crystals grown was elucidated through first-principles calculations. The obtained results indicated that K1−xNaxTa1−yNbyO3 crystals can be used as a high-quality, lead-free piezoelectric material. PMID:27160075

  10. Piezoelectric properties of high Curie temperature barium titanate-bismuth perovskite-type oxide system ceramics

    NASA Astrophysics Data System (ADS)

    Wada, Satoshi; Yamato, Keisuke; Pulpan, Petr; Kumada, Nobuhiro; Lee, Bong-Yeon; Iijima, Takashi; Moriyoshi, Chikako; Kuroiwa, Yoshihiro

    2010-11-01

    Barium titanate (BaTiO3, BT)—bismuth magnesium titanium oxide [Bi(Mg0.5Ti0.5)O3, BMT] system ceramics were prepared in an ambient atmosphere in order to increase the Curie temperature (Tc) of BT above 132 °C. A single perovskite phase was observed for BT-BMT ceramics with BMT compositions less than 50 mol %, and their relative densities were greater than 94%. Synchrotron measured x-ray diffraction patterns revealed that all the cations in the ceramics were homogeneously distributed. The temperature dependence of the dielectric properties revealed that the BT-BMT system ceramics exhibited relaxorlike characteristics with a dielectric maximum temperature as high as 360 °C for the 0.5BT-0.5BMT ceramic. The apparent piezoelectric constant (d∗) was 60 pC/N for the 0.4BT-0.6BMT ceramic. Based upon these results, the BT-BMT system shows potential as a new type of lead-free material for high Tc piezoelectric applications.

  11. Low electric-field driven ultrahigh electrostrains in Sb-substituted (Na,K)NbO3 lead-free ferroelectric ceramics

    NASA Astrophysics Data System (ADS)

    Fu, Jian; Zuo, Ruzhong; Qi, He; Zhang, Chen; Li, Jingfeng; Li, Longtu

    2014-12-01

    Lead-free (Na0.52K0.48)(Nb1-ySby)O3 (NKNSy) ferroelectric ceramics were reported to exhibit an ultrahigh electrostrain (dynamic d33* (=S/E) of 800-1100 pm/V) in a relatively low driving electric field range (1-4 kV/mm). As evidenced by in-situ synchrotron x-ray diffraction and dielectric measurements, the mechanism of generating large strains was ascribed to both the low-field induced reversible rhombohedral-monoclinic phase transition (1-2 kV/mm) and the enhanced domain switching (2-4 kV/mm) owing to the normal to relaxor phase transformation, which contribute to ˜62% and ˜38% of the total strain, respectively. The results indicate that the NKNSy compositions would have excellent potentials for applications of lead-free actuator ceramics.

  12. Giant Strains in Non-Textured (Bi1/2 Na1/2 )TiO3 -Based Lead-Free Ceramics.

    PubMed

    Liu, Xiaoming; Tan, Xiaoli

    2016-01-01

    Giant electric-field-induced strain of 0.70%, corresponding to a d33 * value of 1400 pm V(-1) , is observed in a lead-free (Bi1/2 Na1/2 )TiO3 -based polycrystalline ceramic. This is comparable to the properties of single crystals. An in situ transmission electron microscopy study indicates that the excellent performance originates from phase transitions under the applied electric fields. PMID:26596685

  13. High-Temperature Piezoelectric Ceramic Developed

    NASA Technical Reports Server (NTRS)

    Sayir, Ali; Farmer, Serene C.; Dynys, Frederick W.

    2005-01-01

    Active combustion control of spatial and temporal variations in the local fuel-to-air ratio is of considerable interest for suppressing combustion instabilities in lean gas turbine combustors and, thereby, achieving lower NOx levels. The actuator for fuel modulation in gas turbine combustors must meet several requirements: (1) bandwidth capability of 1000 Hz, (2) operating temperature compatible with the fuel temperature, which is in the vicinity of 400 F, (3) stroke of approximately 4 mils (100 m), and (4) force of 300 lb-force. Piezoelectric actuators offer the fastest response time (microsecond time constants) and can generate forces in excess of 2000 lb-force. The state-of-the-art piezoceramic material in industry today is Pb(Zr,Ti)O3, called PZT. This class of piezoelectric ceramic is currently used in diesel fuel injectors and in the development of high-response fuel modulation valves. PZT materials are generally limited to operating temperatures of 250 F, which is 150 F lower than the desired operating temperature for gas turbine combustor fuel-modulation injection valves. Thus, there is a clear need to increase the operating temperature range of piezoceramic devices for active combustion control in gas turbine engines.

  14. Magnetoelectric coupling in lead-free piezoelectric Lix(K0.5Na0.5)1 - xNb1 - yTayO3 and magnetostrictive CoFe2O4 laminated composites

    NASA Astrophysics Data System (ADS)

    Fu, Jiyong; Santa Rosa, Washington; M'Peko, Jean Claude; Algueró, Miguel; Venet, Michel

    2016-04-01

    To replace lead zirconium titanate in magnetoelectric (ME) composites owing to concerns regarding its toxicity, we investigate the ME coupling in bilayer composites comprising lead-free Lix(K0.5Na0.5)1 - xNb1 - yTayO3 (LKNNT) (piezoelectric) and CoFe2O4 (magnetostrictive) phases. We prepare the LKNNT ceramics and measure its piezoelectric coefficient d31, a crucial ingredient determining ME couplings, for several Li (x = 0.03 , 0.035 , 0.04) and Ta (y = 0.15 , 0.2 , 0.25) concentrations, and find that the highest d31 occurs at y = 0.2 for all the values of x studied here. We then evaluate both the transverse (αE,31) and the longitudinal (αE,33) low-frequency ME coupling coefficients of our composites, for each the above composition of (x , y). At x = 0.03, we find the usual scenario of αE,31 and αE,33, i.e., the strongest ME coupling occurs when d31 is maximal, namely at y = 0.2. On the other hand, interestingly, we also obtain the strongest ME coupling when the LKNNT layer has a relatively weaker d31, e.g., at y = 0.25 for x = 0.035 and y = 0.15 for x = 0.04, following from the interplay of d31 and other ingredients (e.g., dielectric constant). Our calculated ME couplings, with αE,31 in magnitude around twice of αE,33, are comparable to those in lead-based composites. The effect of the volume fraction and interface parameter on the ME coupling is also discussed.

  15. Characterization of porous piezoelectric ceramics: The length expander case

    SciTech Connect

    Gomez Alvarez-Arenas, T.E.; Montero de Espinosa, F.

    1997-12-01

    Porous piezoelectric ceramics and 0{endash}3/3{endash}3 connectivity piezoelectric composites are normally characterized following the Standards on Piezoelectricity. Nevertheless, these materials are not homogeneous and losses are significant. New constitutive and wave equations have been obtained recently for these kind of materials. The objective of this paper is to derive new definitions for the electromechanical coupling coefficients and a suitable characterization procedure according to the new constitutive and wave equations previously mentioned. In particular, the case of the length expander bar mode is analyzed in detail. The study of resonant elements requires the use of suitable boundary conditions. In this case the boundary conditions are borrowed from the theory of poroelasticity and extended for a piezoelectric material. Finally the procedure is applied to characterize a commercial porous piezoelectric ceramic. {copyright} {ital 1997 Acoustical Society of America.}

  16. Giant electrocaloric effect in lead-free Ba0.94Ca0.06Ti1-xSnxO3 ceramics with tunable Curie temperature

    NASA Astrophysics Data System (ADS)

    Wang, Xiangjian; Tian, Fang; Zhao, Chunlin; Wu, Jiagang; Liu, Yang; Dkhil, Brahim; Zhang, Ming; Gao, Zhipeng; Lou, Xiaojie

    2015-12-01

    Electrocaloric effect in lead-free Ba0.94Ca0.06Ti1-xSnxO3 ceramics is studied using an indirect method. The Ba0.94Ca0.06Ti0.875Sn0.125O3 ceramic located near a multi-phase point shows best electrocaloric performance, which provides further experimental evidence for optimizing electrocaloric properties through constructing multiphase coexistence. Giant electrocaloric efficiency (˜0.4 K mm/kV) is achieved in this ceramic at about room temperature at a low electric field of 6 kV/cm. While large electrocaloric temperature (˜0.63 K) is obtained by further enhancing electric field (20 kV/cm), a decrease in electrocaloric efficiency (0.32 K mm/kV) is simultaneously observed, which is attributed to phase transition from first-order to more diffusive second-order under higher electric field.

  17. Flexible High-Performance Lead-Free Na0.47K0.47Li0.06NbO3 Microcube-Structure-Based Piezoelectric Energy Harvester.

    PubMed

    Gupta, Manoj Kumar; Kim, Sang-Woo; Kumar, Binay

    2016-01-27

    Lead-free piezoelectric nano- and microstructure-based generators have recently attracted much attention due to the continuous demand of self-powered body implantable devices. We report the fabrication of a high-performance flexible piezoelectric microgenerator based on lead-free inorganic piezoelectric Na0.47K0.47Li0.06NbO3 (NKLN) microcubes for the first time. The composite generator is fabricated using NKLN microcubes and polydimethylsiloxane (PDMS) polymer on a flexible substrate. The flexible device exhibits excellent performance with a large recordable piezoelectric output voltage of 48 V and output current density of 0.43 μA/cm(2) under vertical compressive force of 2 kgf, for which an energy conversion efficiency of about 11% has been achieved. Piezoresponse and ferroelectric studies reveal that NKLN microcubes exhibited high piezoelectric charge coefficient (d33) as high as 460 pC/N and a well-defined hysteresis loops with remnant polarization and coercive field of 13.66 μC/cm(2) and 19.45 kV/cm, respectively. The piezoelectric charge generation mechanism from NKLN microgenerator are discussed in the light of the high d33 and alignment of electric dipoles in polymer matrix and dielectric constant of NKLN microcubes. It has been demonstrated that the developed power generator has the potential to generate high electric output power under mechanical vibration for powering biomedical devices in the near future. PMID:26735739

  18. Strong piezoelectricity in (1 - x)(K0.4Na0.6)(Nb0.96Sb0.04)O3-xBi0.5K0.5Zr1-ySnyO3 lead-free binary system: identification and role of multiphase coexistence.

    PubMed

    Zheng, Ting; Wu, Jiagang; Xiao, Dingquan; Zhu, Jianguo; Wang, Xiangjian; Xin, Lipeng; Lou, Xiaojie

    2015-03-18

    Here we report a strong piezoelectric activity in (1 - x)(K0.4Na0.6)(Nb0.96Sb0.04)O3-xBi0.5K0.5Zr1-ySnyO3 lead-free ceramics by designing different phase boundaries. The phase boundaries concerning rhombohedral-orthorhombic-tetragonal (R-O-T) and rhombohedral-tetragonal (R-T) multiphase coexistence were attained by changing BKZS and Sn contents and then were identified by the X-ray diffraction patterns as well as temperature-dependent permittivity and ?1 Raman modes associated with BO6 perovskite octahedron. A high strain (strain = 0.21-0.28% and d33* = 707-880 pm/V) and a strong piezoelectric coefficient (d33 = 415-460 pC/N) were shown in the ceramics located at the multiphase coexistence region. The reported results of this work are superior to that (d33* ? 570 pm/V and d33 ? 416 pC/N) of the textured (K,Na,Li)(Nb,Ta,Sb)O3 ceramics [Nature 2004, 432, 84]. We believe that the material system of this work will become one of the most promising candidates for piezoelectric actuators. PMID:25734451

  19. Effects of Li content on the phase structure and electrical properties of lead-free (K0.46-x/2Na0.54-x/2Lix)(Nb0.76Ta0.20Sb0.04)O3 ceramics

    NASA Astrophysics Data System (ADS)

    Chang, Yunfei; Yang, Zupei; Hou, Yuting; Liu, Zonghuai; Wang, Zenglin

    2007-06-01

    Lead-free (K0.46-x/2Na0.54-x/2Lix)(Nb0.76Ta0.20Sb0.04)O3 piezoelectric ceramics were prepared by the conventional solid state sintering method without cold-isostatic pressing process. The x-ray diffraction and Raman scattering results show that the phase structure of the ceramics undergoes a transition from pseudocubic to tetragonal phase with increasing x from 0 to 0.10. Significantly enhanced electrical properties (d33=259pC/N, kp=0.42, ɛr=1653, and tan δ =0.027) were obtained in the ceramics with x =0.04 near the morphotropic phase boundary, and only the tetragonal-cubic phase transition was observed above the room temperature in the ɛr-T curve. The temperature stability of the ceramics with x =0.04 was also investigated.

  20. Large electrocaloric effect in lead-free K0.5Na0.5NbO3-SrTiO3 ceramics

    NASA Astrophysics Data System (ADS)

    Koruza, J.; Rožič, B.; Cordoyiannis, G.; Malič, B.; Kutnjak, Z.

    2015-05-01

    The electrocaloric effect (ECE), i.e., the adiabatic temperature change ΔTEC, of the lead-free relaxor ferroelectric 0.85K0.5Na0.5NbO3-0.15SrTiO3 (KNN-STO) ceramics is investigated. The ECE data obtained by a direct method show the existence of a large ECE near the temperature of the dielectric permittivity maximum. Due to the high break-down electric field, a large ΔTEC exceeding 1.2 K at 300 K and 1.9 K at 340 K was observed at 159 kV/cm in a broad temperature range of 80 K. Such a high ECE response near the room temperature is comparable to that found in lead-based ceramic materials, thus making KNN-STO a strong candidate to replace lead-based materials in future electrocaloric applications.

  1. Resolution of the ferroelectric domains structure in (K,Na)NbO3-based lead-free ceramics by confocal Raman microscopy

    NASA Astrophysics Data System (ADS)

    Rubio-Marcos, F.; Del Campo, A.; Fernández, J. F.

    2013-05-01

    We highlight some practical aspects in the study of ferroelectric domains in lead-free modified (K,Na)NbO3 piezoceramics through Confocal Raman Microscopy (CRM). In addition, CRM allows the determination of the nature of domain walls and correlation between the structure and piezoelectric properties. The typical configuration of the ferroelectric domain is analyzed in polycrystalline grains of small sizes not exceeding 6 μm, where tetragonal and orthorhombic domains are coexisting. The accumulated stress produced by the phase coexistence softens the octahedron force constant and reduces the polarization. So, the polarization decrease is associated to the apparition of the orthorhombic phase (O). Finally, we believe that the general strategy and design principles described in this study will open new avenues in developing novel strategies of domains characterization that allow improving the piezoresponse.

  2. Low electric-field driven ultrahigh electrostrains in Sb-substituted (Na,K)NbO{sub 3} lead-free ferroelectric ceramics

    SciTech Connect

    Fu, Jian; Zuo, Ruzhong E-mail: rzzuo@hotmail.com; Qi, He; Zhang, Chen; Li, Jingfeng; Li, Longtu

    2014-12-15

    Lead-free (Na{sub 0.52}K{sub 0.48})(Nb{sub 1−y}Sb{sub y})O{sub 3} (NKNS{sub y}) ferroelectric ceramics were reported to exhibit an ultrahigh electrostrain (dynamic d{sub 33}* (=S/E) of 800–1100 pm/V) in a relatively low driving electric field range (1–4 kV/mm). As evidenced by in-situ synchrotron x-ray diffraction and dielectric measurements, the mechanism of generating large strains was ascribed to both the low-field induced reversible rhombohedral-monoclinic phase transition (1–2 kV/mm) and the enhanced domain switching (2–4 kV/mm) owing to the normal to relaxor phase transformation, which contribute to ∼62% and ∼38% of the total strain, respectively. The results indicate that the NKNS{sub y} compositions would have excellent potentials for applications of lead-free actuator ceramics.

  3. Manufacturing of PZT-nickel functionally graded piezoelectric ceramics

    NASA Astrophysics Data System (ADS)

    Rubio, Wilfredo M.; Silva, Emílio C. N.; Buiochi, Flávio

    2012-05-01

    A recent approach for designing and manufacturing piezoelectric ceramics consists of using the functionally graded materials (FGM) concept. In this work, nickel (Ni) is used to generate a new PZT-Ni graded ceramic and its dynamic behavior is experimentally explored. The PZT-Ni graded ceramic is manufactured by using the technique of Spark Plasma Sintering (SPS). The ceramic is graded from the top to the bottom surface (along 6 mm of thickness). Specifically, five layers of green powders are sintered: 100 wt% PZT-5A, 90 wt% PZT-5A and 10 wt% Ni, 80 wt% PZT-5A and 20 wt% Ni, 70 wt% PZT-5A and 30 wt% Ni, 60 wt% PZT-5A and 40 wt% Ni. Thus, Ni is used as a second phase, which is added to a PZT-5A matrix, changing its concentration. No manufacturing defects or cracks or exfoliated layers are observed. However, graphite diffusion is observed from the graphite die into the graded ceramic, which does not affect its performance; hence, the ceramic contains enough piezoelectric properties, which allows its polarization and dynamic characterization by determining the impedance curve of the PZT-Ni graded ceramic. The PZT-Ni graded ceramic vibrates at 1.04 MHz, 1.55 MHz and 2.07 MHz.

  4. Dielectric and Piezoelectric Properties of Sodium Bismuth Titanate Ceramics with KCe Substitution

    NASA Astrophysics Data System (ADS)

    Xu, Jian-Xiu; Zhao, Liang; Zhang, Cheng-Ju

    2008-12-01

    The piezoelectric properties of the (KCe)-substituted sodium bismuth titanate (Na0.5Bi4.5Ti4O15, NBT) piezoelectric ceramics are investigated. The piezoelectric properties of NBT ceramics are significantly enhanced by (KCe) substitution. The Curie temperature Tc, and piezoelectric coefficient dss for the (KCe)-substituted NBT are found to be 663°C, and 27pC/N, respectively. Dielectric and annealing spectroscopy present that the (KCe) co-substituted NBT piezoelectric ceramics possess stable piezoelectric properties.

  5. Enhanced piezoelectric and mechanical properties of AlN-modified BaTiO3 composite ceramics.

    PubMed

    Xu, Dan; Wang, Lidong; Li, Weili; Wang, Wei; Hou, Yafei; Cao, Wenping; Feng, Yu; Fei, Weidong

    2014-07-14

    BaTiO3-xAlN (BT-xAlN) composite ceramics were prepared by conventional solid state reaction sintering. The effects of the AlN content on the crystalline structures, densities, and electrical and mechanical properties of the BT ceramics were investigated. The BT-1.5%AlN ceramic exhibits a good piezoelectric constant of 305 pC N(-1) and an improved Vickers hardness of 5.9 GPa. The enhanced piezoelectricity originates from interactions between defect dipoles and spontaneous polarization inside the domains due to the occurrence of local symmetry, caused by the preferential distribution of the Al(3+)-N(3-) pairs vertical to the c axis. The hardening of the material is attributed to the improved density, and particle and grain boundary strengthening. Our work indicates that if a suitable doping ion pair is designed, lead-free ceramic systems prepared from ordinary raw materials by a conventional sintering method have a high probability of exhibiting good piezoelectric and mechanical properties simultaneously. PMID:24852079

  6. Effect of Li2CO3 addition on the structural, optical, ferroelectric, and electric-field-induced strain of lead-free BNKT-based ceramics

    NASA Astrophysics Data System (ADS)

    van Quyet, Nguyen; Huu Bac, Luong; Odkhuu, Dorj; Duc Dung, Dang

    2015-10-01

    In this work, we reported the effect of Li2CO3 addition on the structural, optical, ferroelectric properties and electric-field-induced strain of Bi0.5(Na,K)0.5TiO3 (BNKT) solid solution with CaZrO3 ceramics. Both rhombohedral and tetragonal structures were distorted after adding Lithium (Li). The band gap values decreased from 2.91 to 2.69 eV for 5 mol% Li-addition. The maximum polarization and remanent polarization decreased from 49.66 ?C/cm2 to 27.11 ?C/cm2 and from 22.93 ?C/cm2 to 5.35 ?C/cm2 for un-doped and 5 mol% Li- addition BNKT ceramics, respectively. The maximum Smax/Emax value was 567 pm/V at 2 mol% Li2CO3 access. We expected this work will help to understand the role of A-site dopant in lead-free ferroelectric BNKT materials.

  7. Energy harvesting performance of piezoelectric ceramic and polymer nanowires.

    PubMed

    Crossley, Sam; Kar-Narayan, Sohini

    2015-08-28

    Energy harvesting from ubiquitous ambient vibrations is attractive for autonomous small-power applications and thus considerable research is focused on piezoelectric materials as they permit direct inter-conversion of mechanical and electrical energy. Nanogenerators (NGs) based on piezoelectric nanowires are particularly attractive due to their sensitivity to small-scale vibrations and may possess superior mechanical-to-electrical conversion efficiency when compared to bulk or thin-film devices of the same material. However, candidate piezoelectric nanowires have hitherto been predominantly analyzed in terms of NG output (i.e. output voltage, output current and output power density). Surprisingly, the corresponding dynamical properties of the NG, including details of how the nanowires are mechanically driven and its impact on performance, have been largely neglected. Here we investigate all realizable NG driving contexts separately involving inertial displacement, applied stress T and applied strain S, highlighting the effect of driving mechanism and frequency on NG performance in each case. We argue that, in the majority of cases, the intrinsic high resonance frequencies of piezoelectric nanowires (∼tens of MHz) present no barrier to high levels of NG performance even at frequencies far below resonance (<1 kHz) typically characteristic of ambient vibrations. In this context, we introduce vibrational energy harvesting (VEH) coefficients ηS and ηT, based on intrinsic materials properties, for comparing piezoelectric NG performance under strain-driven and stress-driven conditions respectively. These figures of merit permit, for the first time, a general comparison of piezoelectric nanowires for NG applications that takes into account the nature of the mechanical excitation. We thus investigate the energy harvesting performance of prototypical piezoelectric ceramic and polymer nanowires. We find that even though ceramic and polymer nanowires have been found, in certain cases, to have similar energy conversion efficiencies, ceramics are more promising in strain-driven NGs while polymers are more promising for stress-driven NGs. Our work offers a viable means of comparing NG materials and devices on a like-for-like basis that may be useful for designing and optimizing nanoscale piezoelectric energy harvesters for specific applications. PMID:26234477

  8. Energy harvesting performance of piezoelectric ceramic and polymer nanowires

    NASA Astrophysics Data System (ADS)

    Crossley, Sam; Kar-Narayan, Sohini

    2015-08-01

    Energy harvesting from ubiquitous ambient vibrations is attractive for autonomous small-power applications and thus considerable research is focused on piezoelectric materials as they permit direct inter-conversion of mechanical and electrical energy. Nanogenerators (NGs) based on piezoelectric nanowires are particularly attractive due to their sensitivity to small-scale vibrations and may possess superior mechanical-to-electrical conversion efficiency when compared to bulk or thin-film devices of the same material. However, candidate piezoelectric nanowires have hitherto been predominantly analyzed in terms of NG output (i.e. output voltage, output current and output power density). Surprisingly, the corresponding dynamical properties of the NG, including details of how the nanowires are mechanically driven and its impact on performance, have been largely neglected. Here we investigate all realizable NG driving contexts separately involving inertial displacement, applied stress T and applied strain S, highlighting the effect of driving mechanism and frequency on NG performance in each case. We argue that, in the majority of cases, the intrinsic high resonance frequencies of piezoelectric nanowires (∼tens of MHz) present no barrier to high levels of NG performance even at frequencies far below resonance (<1 kHz) typically characteristic of ambient vibrations. In this context, we introduce vibrational energy harvesting (VEH) coefficients ηS and ηT, based on intrinsic materials properties, for comparing piezoelectric NG performance under strain-driven and stress-driven conditions respectively. These figures of merit permit, for the first time, a general comparison of piezoelectric nanowires for NG applications that takes into account the nature of the mechanical excitation. We thus investigate the energy harvesting performance of prototypical piezoelectric ceramic and polymer nanowires. We find that even though ceramic and polymer nanowires have been found, in certain cases, to have similar energy conversion efficiencies, ceramics are more promising in strain-driven NGs while polymers are more promising for stress-driven NGs. Our work offers a viable means of comparing NG materials and devices on a like-for-like basis that may be useful for designing and optimizing nanoscale piezoelectric energy harvesters for specific applications.

  9. Determination of crystallographic orientation of lead-free piezoelectric (K,Na)NbO{sub 3} epitaxial thin films grown on SrTiO{sub 3} (100) surfaces

    SciTech Connect

    Yu, Qi; Zhu, Fang-Yuan; Cheng, Li-Qian; Wang, Ke; Li, Jing-Feng

    2014-03-10

    Crystallographic structure of sol-gel-processed lead-free (K,Na)NbO{sub 3} (KNN) epitaxial films on [100]-cut SrTiO{sub 3} single-crystalline substrates was investigated for a deeper understanding of its piezoelectric response. Lattice parameter measurement by high-resolution X-ray diffraction and transmission electron microscopy revealed that the orthorhombic KNN films on SrTiO{sub 3} (100) surfaces are [010] oriented (b-axis-oriented) rather than commonly identified c-axis orientation. Based on the crystallographic orientation and corresponding ferroelectric domain structure investigated by piezoresponse force microscopy, the superior piezoelectric property along b-axis of epitaxial KNN films than other orientations can be explained.

  10. The preparation and the effects of K/Na ratio on the electrical properties of 0.95(Na0.96- x K x Li0.04)(Nb0.89Sb0.07Ta0.04)O3-0.05KNbO3 lead-free ceramics

    NASA Astrophysics Data System (ADS)

    Ma, Jian; Xiao, Ding-quan; Wu, Bo; Wu, Jia-gang; Zhu, Jian-guo

    2014-07-01

    0.95(Na0.96- x K x Li0.04)(Nb0.89Sb0.07Ta0.04)O3-0.05KNbO3 (abbreviated as K x NLNST-KN, x = 0.32 - 0.52) lead-free piezoelectric ceramics were prepared by using the conventional solid-state sintering method, and the intentional addition of a pre-calcined KNbO3 powder was used as a sintering aid that might inhibit and compensate for the volatilization of alkali metals during the sintering process. The preparation of the ceramics and the effects of K/Na ratio on the structure and the electrical properties of these ceramics were studied in detail. Compared with the relatively higher sintering temperature of Li-, Sb-, and Ta-modified KNN ceramics reported in the literature, the dense ceramic samples were obtained at a reduced temperature of 1060 °C, and the ceramics with x = 0.44 possessed optimal properties: d 33 = 298 pC/N, k p = 48%, P r = 21.9 μC/cm2, and E c = 11.5 kV/cm.

  11. Domain size engineering in 0.5%MnO2-(K0.5Na0.5)NbO3 lead free piezoelectric crystals

    NASA Astrophysics Data System (ADS)

    Lin, Dabin; Zhang, Shujun; Cai, Changlong; Liu, Weiguo

    2015-02-01

    The piezoelectric property of [001]-oriented 0.5%MnO2-(K0.5Na0.5)NbO3 (Mn-KNN) crystals was studied as a function of domain size, being poled with different electric fields at 205 °C (above orthorhombic to tetragonal phase transition temperature To-t). The piezoelectric coefficients d33 and relative dielectric constants ɛr were found to increase from 270 pC/N to 350 pC/N and 730 to 850 with the domain size decreasing from 9 to 2 μm, respectively. The thermal stability of piezoelectric property was investigated, where the d33 value for [001]-oriented Mn-KNN crystals with domain size of 2 μm was found to decrease to 330 pC/N at depoling temperature of 150 °C, with minimal variation of ˜6%. The results reveal that domain size engineering is an effective way to improve the piezoelectric properties of Mn-KNN crystals.

  12. Relaxor nature in lead-free Sr{sub 5}LaTi{sub 3}Nb{sub 7}O{sub 30} tetragonal tungsten bronze ceramics

    SciTech Connect

    Li Zhu, Xiao; Department of Materials and Ceramic Engineering, Centre for Research in Ceramics and Composite Materials, CICECO, University of Aveiro, 3810-193 Aveiro ; Li, Kun; Qiang Liu, Xiao; Ming Chen, Xiang; Asif Rafiq, Muhammad

    2013-09-28

    Lead-free tetragonal tungsten bronze Sr{sub 5}LaTi{sub 3}Nb{sub 7}O{sub 30} ceramics were prepared and the correlation of the relaxor nature and crystal structure was studied using dielectric spectroscopy and powder X-ray diffraction. Three dielectric relaxations were observed below the deviation temperature T{sub D}∼ 330 K. Relaxation I and II followed the Vogel-Fulcher law with the freezing temperatures of 189 K and ∼90 K. Low temperature relaxation III, which was first observed in filled tungsten bronze, followed well the Arrhenius law. Dielectric response becomes static below 50 K. Polarization-field (P-E) hysteresis loops were evaluated from 183 K to 298 K. P{sub r} value of 0.41μC/cm{sup 2} was observed at 183 K. Deviation of lattice parameter c from the linear contraction and increasing of tetragonality (c/a ratio) were observed below T{sub D}, reflecting the structure change during the formation of polar nanoregions and the following freezing process. Opposite tendency was observed below 100 K for all the lattice parameters, corresponding to relaxation III. Generally, the main dielectric relaxation I and II were attributed to flipping and breathing of polar nanoregions along c axis, while the concerted rotations of the oxygen octahedra in the ab plane were suggested as the origin of relaxation III.

  13. Measurement of Micro Vibration of Car by Piezoelectric Ceramics

    NASA Astrophysics Data System (ADS)

    Kurihara, Yosuke; Masuyama, Kosuke; Nakamura, Testuo; Bamba, Takeshi; Watanabe, Kajiro

    Recently, there are various accidents and crimes related to the car. In some cases, the accidents and the crimes can be prevented if it is possible to detect a human who is in the car. For example, we can prevent a baby who is left in a car under the hot weather from dehydration or death occurred by heat inside disease. In another case, it is estimated that the United States currently has as many as 12 million illegal immigrants. In order to prevent further influx of illegal immigrants, the police are physically searching incoming vehicles at national boundaries aiming at finding those who are hiding inside. However, the physical inspections require much manpower cost and time. An inspection method to see inside the vehicles through X-ray images has also been used for this end. But the cost and the installation places are the problems of the large-scale X-ray system. Proposed in this paper is a piezoelectric ceramic system to handily measure the micro vibrations of motor vehicles. And applying the algorithm of Support Vector Machine (SVM), the existence of human body inside vehicles can be detected. The experiment was carried out using four types of vehicles: a mini car; an auto mobile; a van; and a truck weighing 1.5 tons. As the results, the correct determination ratio was 91.2% for the experiment with the piezoelectric ceramic under the front wheels and 97.0% under the rear wheels, when the vehicle used for the examination had also been used together with other three types of vehicles to obtain SVM training data. When the vehicle used for the examination had not been used together with the other three to obtain SVM training data, on the other hand, the correct determination ratio was 93.7% for the experiment with the piezoelectric ceramic under the front wheels and 95.7% under the rear wheels.

  14. Micro-motion exposure method based on PZT piezoelectric ceramics

    NASA Astrophysics Data System (ADS)

    Sun, Wenjun; Zhang, Mei-heng; Meng, Zhong

    2009-07-01

    There mainly is laser digital photofinishing technique and digital photofinishing technique based on LCD consisting of TFT and LCOS in the digital photofinishing field at the present time. The former have a good many merit such as wide color gamut, high processing rate, large output size and high brightness, but his cost is very high, his maintain technique being comparatively complex, that result in difficult use for people. The utilization ratio of the latter is low because of lower resolution and lower aperture ratio for LCD, but the digital photofinishing based on LCD have lower cost and higher utilization ration, being suitable for people's current standard of living. Considering above mentioned problem, a micro-motion exposure method based on PZT piezoelectric ceramics used in digital image photofinishing is presented. The two-dimension micro-motion exposure system consisting of PZT piezoelectric ceramics, LCD panel, polarizing film and spring strip is designed. By means of PZT piezoelectric ceramics the LCD panel is removed about the one half of the pixel size of the LCD panel for four times from the original place, at the same time imaging system is exposed four times at the printing paper. The software is used to control the time synchronization, the exposure time and motion range of the LCD panel. The system has advantages such as shorter response time than 0.1seconds, lesser motion error than 0.01 microns, high stability and repeatability. Experimental results show that the proposed micro-motion exposure method improve the picture brightness and enlarge output size, at the meantime reducing the cost of the system.

  15. (1 - x)(K0.48Na0.52)(Nb(0.95-y-z)Ta(z)Sb(y))O3-xBi0.5(Na0.82K0.18)0.5ZrO3 lead-free ceramics: composition dependence of the phase boundaries and electrical properties.

    PubMed

    Lv, Xiang; Wu, Jiagang; Xiao, Dingquan; Tao, Hong; Yuan, Yuan; Zhu, Jianguo; Wang, Xiangjian; Lou, Xiaojie

    2015-03-14

    In this work, (1 - x)(K0.48Na0.52)(Nb(0.95-y-z)Ta(z)Sb(y))O3-xBi0.5(Na0.82K0.18)0.5ZrO3, {abbreviation: KNNST-BNKZ-x-y-z} lead-free piezoceramics were prepared by a conventional solid-state reaction method, and the composition dependence of their phase structures and electrical properties was systematically discussed. Doping with Sb(5+), Ta(5+), and BNKZ plays an important role on the phase boundaries as well as piezoelectric activity. A three-phase coexistence involving rhombohedral-orthorhombic-tetragonal (R-O-T) phases was observed in the ceramics with 0.0325 ? x ? 0.05, 0.035 ? x ? 0.065, 0.05 ? z ? 0.08, indicating that doping with BNKZ, Ta(5+), and Sb(5+) can induce the formation of such a phase boundary by simultaneously increasing TR-O and decreasing TO-T. Enhanced piezoelectric behavior was observed in the ceramics located in the composition region of the R-O-T phase boundary, and a high d33 value of 400 pC N(-1) can be attained by refining their compositions (e.g., x = 0.0325, y = 0.035, and z = 0.05), together with a high TC value of ?240 C. Of particular interest is that a large electric field-induced strain of 0.18% (Smax/Emax = 706 pm V(-1)) was also found in the ceramics with x = 0.0325, y = 0.035, and z = 0.05 under a low electric field of 2.5 kV mm(-1). As a result, the piezoelectric activity as well as the strain can be operated in the material system by refining x, y, and z content. PMID:25679361

  16. Good Quality Factor in GdMnO3-Doped (K0.5Na0.5)NbO3 Piezoelectric Ceramics

    NASA Astrophysics Data System (ADS)

    Bucur, Raul Alin; Badea, Iuliana; Bucur, Alexandra Ioana; Novaconi, Stefan

    2016-06-01

    (1 - x)(K0.5Na0.5)NbO3 - xGdMnO3 (KNN- xGM) ferroelectric ceramics (0 ≤ x ≤ 5 mol.%) were obtained through a solid state technique. For all the studied compositions, orthorhombic perovskite crystalline structures were obtained at room temperature. GdMnO3 suppresses the grain growth and gives rather homogenous microstructures as the concentration increases. The doped ceramics exhibita good dielectric response, a "hard" ferroelectric behavior and good piezoelectric properties. An improved mechanical quality factor of 1180 and a high Curie temperature T C = 400°C, coupled with k p = 0.426, makes the composition x = 1 mol.% GdMnO3 suitable for lead-free piezoelectric materials for high-power and high-temperature applications.

  17. Good Quality Factor in GdMnO3-Doped (K0.5Na0.5)NbO3 Piezoelectric Ceramics

    NASA Astrophysics Data System (ADS)

    Bucur, Raul Alin; Badea, Iuliana; Bucur, Alexandra Ioana; Novaconi, Stefan

    2016-02-01

    (1 - x)(K0.5Na0.5)NbO3 - xGdMnO3 (KNN-xGM) ferroelectric ceramics (0 ≤ x ≤ 5 mol.%) were obtained through a solid state technique. For all the studied compositions, orthorhombic perovskite crystalline structures were obtained at room temperature. GdMnO3 suppresses the grain growth and gives rather homogenous microstructures as the concentration increases. The doped ceramics exhibita good dielectric response, a "hard" ferroelectric behavior and good piezoelectric properties. An improved mechanical quality factor of 1180 and a high Curie temperature T C = 400°C, coupled with k p = 0.426, makes the composition x = 1 mol.% GdMnO3 suitable for lead-free piezoelectric materials for high-power and high-temperature applications.

  18. Composition design and electrical properties in (1-y)(K0.40Na0.60)0.985Li0.015(Nb1-xSbx)O3-yBi0.5Na0.5ZrO3 lead-free ceramics

    NASA Astrophysics Data System (ADS)

    Yuan, Yuan; Wu, Jiagang; Tao, Hong; Lv, Xiang; Wang, Xiangjian; Lou, Xiaojie

    2015-02-01

    To realize the enhancement in piezoelectric activities, the composition-induced phase boundaries in (1-y)(K0.40Na0.60)0.985Li0.015(Nb1-xSbx)O3-yBi0.5Na0.5ZrO3 lead-free ceramics were designed and fabricated by the conventional solid-state method. We presented the evolutions of their phase structure, microstructure, and electrical properties with the change of Sb5+ and Bi0.5Na0.5ZrO3 contents. A rhombohedral-tetragonal phase boundary was successfully built in the composition region of 0.04 ≤ x ≤ 0.09 (y = 0.025) and 0.025 ≤ y ≤ 0.035 (x = 0.06), and then the desirable piezoelectric coefficients and bipolar strains (e.g., d33˜390 pC/N, kp˜0.45, Smax˜0.2%, and TC˜250 °C) were simultaneously induced. We think that this may provide a direction of designing high-performance (K,Na)NbO3-based ceramics.

  19. Lead-free piezoelectric system (Na0.5Bi0.5)TiO3-BaTiO3: Equilibrium structures and irreversible structural transformations driven by electric field and mechanical impact

    NASA Astrophysics Data System (ADS)

    Garg, Rohini; Rao, Badari Narayana; Senyshyn, Anatoliy; Krishna, P. S. R.; Ranjan, Rajeev

    2013-07-01

    The structure-property correlation in the lead-free piezoelectric (1-x)(Na0.5Bi0.5)TiO3-(x)BaTiO3 has been systematically investigated in detail as a function of composition (0piezoelectric measurement, x-ray, and neutron powder diffraction methods. Although x-ray diffraction study revealed three distinct composition ranges characterizing different structural features in the equilibrium state at room temperature: (i) monoclinic (Cc)+rhombohedral (R3c) for the precritical compositions, 0≤x≤0.05, (ii) cubiclike for 0.06≤x≤0.0675, and (iii) morphotropic phase boundary (MPB) like for 0.07≤x<0.10, Raman and neutron powder diffraction studies revealed identical symmetry for the cubiclike and the MPB compositions. The cubiclike structure undergoes irreversible phase separation by electric poling as well as by pure mechanical impact. This cubiclike phase exhibits relaxor ferroelectricity in its equilibrium state. The short coherence length (˜50 Å) of the out-of-phase octahedral tilts does not allow the normal ferroelectric state to develop below the dipolar freezing temperature, forcing the system to remain in a dipolar glass state at room temperature. Electric poling helps the dipolar glass state to transform to a normal ferroelectric state with a concomitant enhancement in the correlation length of the out-of-phase octahedral tilt.

  20. Growth and characterization of lead-free piezoelectric BaZr0.2Ti0.8O3-Ba0.7Ca0.3TiO3 thin films on Si substrates

    NASA Astrophysics Data System (ADS)

    Luo, B. C.; Wang, D. Y.; Duan, M. M.; Li, S.

    2013-04-01

    Lead-free piezoelectric BaZr0.2Ti0.8O3-Ba0.7Ca0.3TiO3 (BCZT) thin films were grown on La0.7Sr0.3MnO3-buffered Si (0 0 1) by off-axis RF magnetron sputtering at temperatures ranging from 550 to 810 °C. In this article, we present the detailed investigation on structure, leakage current behaviors and electromechanical properties of BCZT thin films. The crystallographic texture and grain size of the as-grown thin films are strongly dependent on the growth temperature, which consequently affects the leakage behaviors and local electromechanical properties. The crystallographic orientation becomes better and the grain size increases when increased the substrate temperature. The dominant leakage mechanism is found to be space-charge-limited conduction at low electric field, while a Fowler-Nordheim tunneling is confirmed in high electric field region for the films deposited at 710 °C and 810 °C. The increasing growth temperature also leads to remarkable improvement in the local electromechanical properties of the films. The BCZT film deposited at an optimal temperature of 810 °C exhibits a considerably high effective piezoelectric coefficient d33,f of 94 ± 4 pm/V, which is comparable to that of a typical lead zirconate titanate thin film.

  1. Porosity Dependence of Piezoelectric Properties for Porous Potassium Niobate System Ceramics

    NASA Astrophysics Data System (ADS)

    Wada, S.; Mase, Y.; Shimizu, S.; Maeda, K.; Fujii, I.; Nakashima, K.; Pulpan, P.; Miyajima, N.

    2011-10-01

    Porous potassium niobate (KNbO3, KN) system ceramics were prepared by a conventional sintering method using carbon black (CB) nanoparticles. First, KN nanoparticles with a size of 100 nm was mixed with CB nanoparticles and binder using ball milling with ethanol. The mixture was dried, and pressed into pellets using uniaxial pressing. After binder burnout, these ceramics was sintered in air. Their piezoelectric properties were measured and discussed a relationship between porosity and piezoelectric properties. As the results, with increasing porosity, piezoelectric g33 constant increased significantly, which suggested that porous ceramics were effective for stress sensor application.

  2. High-frequency ultrasonic transducer based on lead-free BSZT piezoceramics.

    PubMed

    Lee, S T F; Lam, K H; Zhang, X M; Chan, H L W

    2011-10-01

    This paper describes the fabrication and evaluation of a high-frequency (40MHz) transducer based on lead-free piezoceramics for ultrasonic imaging. The transducer with an aperture size of 0.9mm has been fabricated using barium strontium zirconate titanate ((Ba(0.95)Sr(0.05))(Zr(0.05)Ti(0.95))O(3), abbreviated as BSZT) ceramics. The lead-free BSZT has a piezoelectric d(33) coefficient of 300 pC/N and an electromechanical coupling factor k(t) of 0.45. High-frequency ultrasound transducers were fabricated and a bandwidth of 76.4% has been achieved with an insertion loss of -26dB. Applications in high resolution biological and medical imaging could be possible with this lead-free material. PMID:21477833

  3. Three-dimensional ceramic molding process based on microstereolithography for the production of piezoelectric energy harvesters

    NASA Astrophysics Data System (ADS)

    Maruo, Shoji; Sugiyama, Kenji; Daicho, Yuya; Monri, Kensaku

    2014-03-01

    A three-dimensional (3-D) molding process using a master polymer mold produced by microstereolithography has been developed for the production of piezoelectric ceramic elements. In this method, ceramic slurry is injected into a 3-D polymer mold via a centrifugal casting process. The polymer master mold is thermally decomposed so that complex 3-D piezoelectric ceramic elements can be produced. As an example of 3-D piezoelectric ceramic elements, we produced a spiral piezoelectric element that can convert multidirectional loads into a voltage. It was confirmed that a prototype of the spiral piezoelectric element could generate a voltage by applying a load in both parallel and lateral directions in relation to the helical axis. The power output of 123 pW was obtained by applying the maximum load of 2.8N at 2 Hz along the helical axis. In addition, to improve the performance of power generation, we utilized a two-step sintering process to obtain dense piezoelectric elements. As a result, we obtained a sintering body with relative density of 92.8%. Piezoelectric constant d31 of the sintered body attained to -40.0 pC/N. Furthermore we analyzed the open-circuit voltage of the spiral piezoelectric element using COMSOL multiphysics. As a result, it was found that use of patterned electrodes according to the surface potential distribution of the spiral piezoelectric element had a potential to provide high output voltage that was 20 times larger than that of uniform electrodes.

  4. Overview of NASA Langley's Piezoelectric Ceramic Packaging Technology and Applications

    NASA Technical Reports Server (NTRS)

    Bryant, Robert G.

    2007-01-01

    Over the past decade, NASA Langley Research Center (LaRC) has developed several actuator packaging concepts designed to enhance the performance of commercial electroactive ceramics. NASA LaRC focused on properly designed actuator and sensor packaging for the following reasons, increased durability, protect the working material from the environment, allow for proper mechanical and electrical contact, afford "ready to use" mechanisms that are scalable, and develop fabrication methodology applicable to any active material of the same physical class. It is more cost effective to enhance or tailor the performance of existing systems, through innovative packaging, than to develop, test and manufacture new materials. This approach led to the development of several solid state actuators that include THUNDER, the Macrofiber Composite or (MFC) and the Radial Field Diaphragm or (RFD). All these actuators are fabricated using standard materials and processes derived from earlier concepts. NASA s fabrication and packaging technology as yielded, piezoelectric actuators and sensors that are easy to implement, reliable, consistent in properties, and of lower cost to manufacture in quantity, than their predecessors (as evidenced by their continued commercial availability.) These piezoelectric actuators have helped foster new research and development in areas involving computational modeling, actuator specific refinements, and engineering system redesign which led to new applications for piezo-based devices that replace traditional systems currently in use.

  5. Enhancing pyroelectric properties of Li-doped (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 lead-free ceramics by optimizing calcination temperature

    NASA Astrophysics Data System (ADS)

    Liu, Xing; Chen, Zhihui; Wu, Dun; Fang, Bijun; Ding, Jianning; Zhao, Xiangyong; Xu, Haiqing; Luo, Haosu

    2015-07-01

    The 1 wt % Li-doped (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 (BCZT-Li) ceramics were prepared by a citrate method. The effects of calcination temperature on the structure and pyroelectric properties of the BCZT-Li ceramics were investigated. The orthorhombic phase and tetragonal phase coexist in all the BCZT-Li ceramics calcined at different temperatures. All the BCZT-Li powders exhibit the type III adsorption-desorption curves. The increase of calcination temperature leads to the growth of the particle size of the BCZT-Li powders. However, the abnormal growth of grains appears when the calcination temperature exceeds 650 °C, leading to the deterioration of pyroelectric properties of the BCZT-Li ceramics. The BCZT-Li ceramics calcined at 650 °C exhibit the best pyroelectric properties, in which the pyroelectric parameters p, Fd, Fv, and Fi is 860 µC·m-2·K-1, 15.8 µPa-1/2 (100 Hz), 0.015 m2/C (100 Hz), and 407.6 pm/V, respectively. The excellent pyroelectric properties of the BCZT-Li ceramics calcined at 650 °C can be attributed to the polymorphic ferroelectric phase transition occurring around room temperature and the optimized calcination temperature. Such investigations reveal that the BCZT-Li ceramics are promising lead-free materials in the pyroelectric devices.

  6. Long-period modulated structure and electric-field-induced structural transformation in N a0.5B i0.5Ti O3 -based lead-free piezoelectrics

    NASA Astrophysics Data System (ADS)

    Khatua, Dipak Kumar; Senyshyn, Anatoliy; Ranjan, Rajeev

    2016-04-01

    N a0.5B i0.5Ti O3 - based lead-free piezoelectrics exhibiting giant piezostrain are technologically interesting materials for actuator applications. The lack of clarity with regard to the structure of the nonpolar phase of this system has hindered the understanding of the structural mechanism associated with the giant piezostrain and other related phenomena. In this paper, we have investigated the structure and field-induced phase transformation behavior of a model system (0.94 -x )N a0.5B i0.5Ti O3-0.06 BaTi O3-x K0.5N a0.5Nb O3 (0.0 ≤x ≤0.025 ). A detailed structural analysis using neutron powder diffraction revealed that the nonpolar phase is neither cubic nor a mixture of rhombohedral (R 3 c ) and tetragonal (P 4 b m ) phases as commonly reported in literature but exhibits a long-period modulated structure, which is most probably of the type √{2 }×√{2 }×n with n =16 . Our results suggest that the giant piezoelectric strain is associated with a field-induced phase transformation of the long-period modulated structure to rhombohedral R 3 c structure above a critical field. We also demonstrate that the giant piezostrain is lost if the system retains a fraction of the field-induced R 3 c phase. A possible correlation among depolarization temperature, giant piezostrain, and its electrical fatigue behavior has also been indicated.

  7. Long ranged structural modulation in the pre-morphotropic phase boundary cubic-like state of the lead-free piezoelectric Na{sub 1/2}Bi{sub 1/2}TiO{sub 3}-BaTiO{sub 3}

    SciTech Connect

    Garg, Rohini; Narayana Rao, Badari; Ranjan, Rajeev; Senyshyn, Anatoliy

    2013-12-21

    The nature of the pre-morphotropic phase boundary (MPB) cubic-like state in the lead-free piezoelectric ceramics (1−x)Na{sub 1/2}Bi{sub 1/2}TiO{sub 3}-(x)BaTiO{sub 3} at x ∼ 0.06 has been examined in detail by electric field and temperature dependent neutron diffraction, x-ray diffraction, dielectric and ferroelectric characterization. The superlattice reflections in the neutron diffraction patterns cannot be explained with the tetragonal P4bm and the rhombohedral (R3c) phase coexistence model. The cubic like state is rather a result of long ranged modulated complex octahedral tilt. This modulated structure exhibits anomalously large dielectric dispersion. The modulated structure transforms to a MPB state on poling. The field-stabilized MPB state is destroyed and the modulated structure is restored on heating the poled specimen above the Vogel-Fulcher freezing temperature. The results show the predominant role of competing octahedral tilts in determining the nature of structural and polar states in Na{sub 1/2}Bi{sub 1/2}TiO{sub 3}-based ferroelectrics.

  8. Electromechanical coupling and temperature-dependent polarization reversal in piezoelectric ceramics.

    PubMed

    Weaver, Paul M; Cain, Markys G; Correia, Tatiana M; Stewart, Mark

    2011-09-01

    Electrostriction plays a central role in describing the electromechanical properties of ferroelectric materials, including widely used piezoelectric ceramics. The piezoelectric properties are closely related to the underlying electrostriction. Small-field piezoelectric properties can be described as electrostriction offset by the remanent polarization which characterizes the ferroelectric state. Indeed, even large-field piezoelectric effects are accurately accounted for by quadratic electrostriction. However, the electromechanical properties deviate from this simple electrostrictive description at electric fields near the coercive field. This is particularly important for actuator applications, for which very high electromechanical coupling can be obtained in this region. This paper presents the results of an experimental study of electromechanical coupling in piezoelectric ceramics at electric field strengths close to the coercive field, and the effects of temperature on electromechanical processes during polarization reversal. The roles of intrinsic ferroelectric strain coupling and extrinsic domain processes and their temperature dependence in determining the electromechanical response are discussed. PMID:21937304

  9. Room temperature electro-caloric effect in lead-free Ba(Zr0.1Ti0.9)1-xSnxO3 (x=0, x=0.075) ceramics

    NASA Astrophysics Data System (ADS)

    Kaddoussi, H.; Gagou, Y.; Lahmar, A.; Belhadi, J.; Allouche, B.; Dellis, J.-L.; Courty, M.; Khemakhem, H.; El Marssi, M.

    2015-01-01

    Electrocaloric effect of lead-free Ba(Zr0.1Ti0.9)1-xSnxO3 (x=0 and x=0.075) ceramics is investigated. In the composition x=0, the electrocaloric strength (ξ) was about 0.23 K mm/kV at Curie temperature. The incorporation of a small amount of tin (Sn) ions in the matrix of Ba(Zr0.1Ti0.9)O3 was found to decrease the Curie temperature TC toward room temperature while the value of the electrocaloric strength remained practically unchanged (ξ=0.22 K mm/kV).

  10. Using Piezoelectric Ceramics for Dust Mitigation of Space Suits

    NASA Technical Reports Server (NTRS)

    Angel, Heather K.

    2004-01-01

    The particles that make up moon dust and Mars soil can be hazardous to an astronaut s health if not handled properly. In the near future, while exploring outer space, astronauts plan to wander the surfaces of unknown planets. During these explorations, dust and soil will cling to their space suits and become imbedded in the fabric. The astronauts will track moon dust and mars soil back into their living quarters. This not only will create a mess with millions of tiny air-born particles floating around, but will also be dangerous in the case that the fine particles are breathed in and become trapped in an astronaut s lungs. research center are investigating ways to remove these particles from space suits. This problem is very difficult due to the nature of the particles: They are extremely small and have jagged edges which can easily latch onto the fibers of the fabric. For the past summer, I have been involved in researching the potential problems, investigating ways to remove the particles, and conducting experiments to validate the techniques. The current technique under investigation uses piezoelectric ceramics imbedded in the fabric that vibrate and shake the particles free. The particles will be left on the planet s surface or collected a vacuum to be disposed of later. The ceramics vibrate when connected to an AC voltage supply and create a small scale motion similar to what people use at the beach to shake sand off of a beach towel. Because the particles are so small, similar to volcanic ash, caution must be taken to make sure that this technique does not further inbed them in the fabric and make removal more difficult. Only a very precise range of frequency and voltage will produce a suitable vibration. My summer project involved many experiments to determine the correct range. Analysis involved hands on experience with oscilloscopes, amplifiers, piezoelectrics, a high speed camera, microscopes and computers. perfect this technology. Someday, vibration to remove dust may a vital component to the space exploration program. In order to mitigate this problem, engineers and scientists at the NASA-Glenn Further research and experiments are planned to better understand and ultimately

  11. Strong piezoelectricity exhibited by large-grained BaTiO3 ceramics

    NASA Astrophysics Data System (ADS)

    Zhang, J. L.; Ji, P. F.; Wu, Y. Q.; Zhao, X.; Tan, Y. Q.; Wang, C. L.

    2014-06-01

    A good understanding of the strong piezoelectric mechanism of BaTiO3 ceramics is very important from both scientific and technological viewpoints. This Letter reports an unusual piezoelectric phenomenon observed in a group of large-grained dense BaTiO3 ceramics with average grain sizes ranging from 5.1 to 16.3 μm, which are prepared with a hydrothermally synthesized BaTiO3 fine powder by hot-press sintering. Among these BaTiO3 ceramics, the one possessing an average grain size of 5.6 μm exhibits a particularly prominent piezoelectricity with piezoelectric constants d33 = 485 pC/N and d33* = 725 pm/V at room temperature and a peak d33 value of 574 pC/N around 8.5 °C. This ceramic is further investigated from the aspects of domain patterns and polarization versus electric field (P-E) loops and compared with a conventionally sintered BaTiO3 ceramic prepared using a solid-state reaction method. The investigation shows that it has the domain patterns of simple parallel stripes inside the grains and the square-like P-E loops and differs significantly from the conventionally sintered ceramic, and indicates that the observed strong piezoelectricity is strongly related to the large remanent polarization.

  12. Enhanced magnetic performance of lead-free (Bi0.5Na0.5)TiO3-CoFe2O4 magnetoelectric ceramics

    NASA Astrophysics Data System (ADS)

    Jarupoom, Parkpoom; Jaita, Pharatree

    2015-09-01

    This research was conducted to study the magnetoelectric ceramics with the composition belonging to (1- x)(Bi0.5Na0.5)TiO3- xCoFe2O4 or (1- x)BNT- xCF (when x = 0 - 0.02 mol fraction). All compositions have been synthesized by a conventional mixed oxide method and sintered at the temperature ranging of 900°C-1150°C. The ceramics were fabricated to investigate the effects of CF on crystal structure, microstructure, magnetoelectric effect (ME) and electrical properties of BNT ceramic. The optimum sintering temperature was found to be 1100°C for pure BNT ceramic and 1000°C for BNT-CF sample group. X-ray diffraction pattern revealed that all compositions exhibited a single perovskite structure without impurity phase. Diffraction peaks from the amount of CF were not observed in these patterns which may be due to the relatively low concentration of CF added into BNT ceramic and may be below the detection limit of the instrument. The reduction of grain size and dielectric improvement were observed when CF was added. The addition of CF improved the magnetic behavior as well as resulted in a slight change in ferroelectric properties. The addition of 2 mol. % CF into BNT was found to be the optimal composition for produce the magnetoelectric materials simultaneously exhibiting good ferromagnetic and ferroelectric properties at room temperature. [Figure not available: see fulltext.

  13. Dielectric and piezoelectric properties of CeO2-added nonstoichiometric (Na0.5K0.5)0.97(Nb0.96Sb0.04)O3 ceramics for piezoelectric energy harvesting device applications.

    PubMed

    Oh, Youngkwang; Noh, Jungrae; Yoo, Juhyun; Kang, Jinhee; Hwang, Larkhoon; Hong, Jaeil

    2011-09-01

    In this study, nonstoichiometric (Na(0.5)K(0.5))(0.97)(Nb(0.96)Sb(0.04))O(3) ceramics were fabricated and their dielectric and piezoelectric properties were investigated according to the CeO(2) addition. In this ceramic composition, CeO(2) addition improved sinterability, electromechanical coupling factor k(p), mechanical quality factor Q(m), piezoelectric constant d(33), and g(33). At the sintering temperature of 1100°C, for the 0.2wt% CeO(2) added specimen, the optimum values of density = 4.359 g/cm(3), k(p) = 0.443, Q(m) = 588, ε(r) = 444, d(33) = 159 pC/N, and g(33) = 35 × 10(-3) V·m/N, were obtained. A piezoelectric energy harvesting device using 0.2 wt% CeO(2)- added lead-free (K(0.5)Na(0.5))(0.97)(Nb(0.96)Sb(0.04))O(3) ceramics and a rectifying circuit for energy harvesting were fabricated and their electrical characteristics were investigated. Under an external vibration acceleration of 0.7 g, when the mass, the frequency of vibration generator, and matching load resistance were 2.4 g, 70 Hz, and 721 Ω, respectively, output voltage and power of piezoelectric harvesting device indicated the optimum values of 24.6 mV(rms) and 0.839 μW, respectively-suitable for application as the electric power source of a ubiquitous sensor network (USN) sensor node. PMID:21937318

  14. New potassium-sodium niobate lead-free piezoceramic: Giant-d33 vs. sintering temperature

    NASA Astrophysics Data System (ADS)

    Wu, Jiagang; Wang, Xiaopeng; Cheng, Xiaojing; Zheng, Ting; Zhang, Binyu; Xiao, Dingquan; Zhu, Jianguo; Lou, Xiaojie

    2014-03-01

    The objective of this work is to achieve a giant piezoelectric constant in (K,Na)NbO3-based lead-free ceramics, and then 0.96K0.46Na0.54Nb0.95Sb0.05O3-0.04Bi0.5(Na0.82K0.18)0.5ZrO3 lead-free piezoceramics were designed and prepared by optimizing the sintering temperature (TS). The rhombohedral-tetragonal phase boundary is found in the ceramics sintered at 1070 ˜ 1105 °C and is suppressed when sintered at low TS of 1060 ˜ 1065 °C. The threshold for TS is 1070 °C in terms of their ferroelectric and piezoelectric properties owing to the difference in the phase boundary and the microstructure, and a large d33 of 388 ˜ 465 pC/N could be attained in a wide TS range of 1070 ˜ 1105 °C, benefiting their practical applications because of broad TS. More interestingly, the ceramic sintered at 1075 °C has a giant d33 of ˜465 pC/N. We think that such a giant d33 of this material system can benefit the development of (K,Na)NbO3-based piezoceramics.

  15. Cement-based piezoelectric ceramic composites for sensor applications in civil engineering

    NASA Astrophysics Data System (ADS)

    Dong, Biqin

    The objectives of this thesis are to develop and apply a new smart composite for the sensing and actuation application of civil engineering. Piezoelectric ceramic powder is incorporated into cement-based composite to achieve the sensing and actuation capability. The research investigates microstructure, polarization and aging, material properties and performance of cement-based piezoelectric ceramic composites both theoretically and experimentally. A hydrogen bonding is found at the interface of piezoelectric ceramic powder and cement phase by IR (Infrared Ray), XPS (X-ray Photoelectron Spectroscopy) and SIMS (Secondary Ion Mass Spectroscopy). It largely affects the material properties of composites. A simple first order model is introduced to explain the poling mechanism of composites and the dependency of polarization is discussed using electromechanical coupling coefficient kt. The mechanisms acting on the aging effect is explored in detail. Dielectrical, piezoelectric and mechanical properties of the cement-based piezoelectric ceramic composites are studied by experiment and theoretical calculation based on modified cube model (n=1) with chemical bonding . A complex circuit model is proposed to explain the unique feature of impedance spectra and the instinct of high-loss of cement-based piezoelectric ceramic composite. The sensing ability of cement-based piezoelectric ceramic composite has been evaluated by using step wave, sine wave, and random wave. It shows that the output of the composite can reflects the nature and characteristics of mechanical input. The work in this thesis opens a new direction for the current actuation/sensing technology in civil engineering. The materials and techniques, developed in this work, have a great potential in application of health monitoring of buildings and infrastructures.

  16. Complete set of material constants of 0.95(Na0.5Bi0.5)TiO3-0.05BaTiO3 lead-free piezoelectric single crystal and the delineation of extrinsic contributions

    NASA Astrophysics Data System (ADS)

    Zheng, Limei; Yi, Xiujie; Zhang, Shantao; Jiang, Wenhua; Yang, Bin; Zhang, Rui; Cao, Wenwu

    2013-09-01

    Lead-free piezoelectric single crystal 0.95(Na0.5Bi0.5)TiO3 (NBT)-0.05BaTiO3 was grown by top-seeded solution growth method, which has rhombohedral symmetry with composition near morphotropic phase boundary. Full set of dielectric, piezoelectric, and elastic constants for [001]c poled domain-engineered single crystal was determined. Excellent electromechanical properties and low dielectric loss (d33 = 360 pC/N, d31 = -113 pC/N, d15 = 162 pC/N, k33 = 0.720, kt = 0.540, and tan ? = 1.1%) make it a good candidate to replace lead-based piezoelectric materials. The depolarization temperature (Td = 135 C) is the highest among all NBT-based materials and its electromechanical coupling properties are very stable below Td. Extrinsic contributions to piezoelectric properties were investigated by Rayleigh analysis.

  17. Analysis of a rectangular ceramic plate in electrically forced thickness-twist vibration as a piezoelectric transformer.

    PubMed

    Yang, Jiashi; Liu, Jinjin; Li, Jiangyu

    2007-04-01

    A rectangular ceramic plate with appropriate electrical load and operating mode is analyzed for piezoelectric transformer application. An exact solution from the three-dimensional equations of linear piezoelectricity is obtained. The solution simulates the real operating situation of a transformer as a vibrating piezoelectric body connected to a circuit. Transforming ratio, input admittance, and efficiency of the transformer are obtained. PMID:17441592

  18. Effects of Zn Substitution on Dielectric and Piezoelectric Properties of (Na0.54K0.46)0.96Li0.04(Nb0.90Ta0.10)O3 Ceramics

    NASA Astrophysics Data System (ADS)

    Byeon, Sunmin; Yoo, Juhyun

    2012-09-01

    In this study, in order to develop lead-free composition ceramics for piezoelectric actuator and sensor applications, (Na0.54K0.46)0.96Li0.04(Nb0.90Ta0.10)1-2x/5ZnxO3 (x = 0-1.5 mol %) composition ceramics were fabricated by a conventional sintering technique at 1110 °C for 5 h. The piezoelectric properties of resultant ceramics were studied with a special emphasis on the influence of Zn-substitution amount. The crystal structure of the specimen exhibited a pure perovskite phase with the coexistence of two phases (orthorhombic and tetragonal phases). However, the phases included tetragonal-rich phases to some extent. The scanning electron microscopy (SEM) images indicated that grain size increased with increasing the content of Zn substitution. High physical properties, namely, piezoelectric constant d33 = 265 pC/N, electromechanical coupling factor kp = 47.5%, dielectric constant ɛr = 1223, and measured density ρ= 4.84 g/cm3 were obtained from the composition ceramic with x = 0.5 mol %. The mechanical quality factor (Qm) was improved from 54 of pure (Na0.54K0.46)0.96Li0.04(Nb0.90Ta0.10)O3 (abbreviated as NKLNT) to 106 by 1.5 mol % Zn substitution. The results reflect that the material is a promising candidate for lead-free high-performance piezoelectric device applications, such as piezoelectric actuators and sensors.

  19. Nanoscale mapping of electromechanical response in ionic conductive ceramics with piezoelectric inclusions

    NASA Astrophysics Data System (ADS)

    Seol, Daehee; Seo, Hosung; Jesse, Stephen; Kim, Yunseok

    2015-08-01

    Electromechanical (EM) response in ion conductive ceramics with piezoelectric inclusions was spatially explored using strain-based atomic force microscopy. Since the sample is composed of two dominant phases of ionic and piezoelectric phases, it allows us to explore two different EM responses of electrically induced ionic response and piezoresponse over the same surface. Furthermore, EM response of the ionic phase, i.e., electrochemical strain, was quantitatively investigated from the comparison with that of the piezoelectric phase, i.e., piezoresponse. These results could provide additional information on the EM properties, including the electrochemical strain at nanoscale.

  20. Fabrication of piezoelectric ceramic micro-actuator and its reliability for hard disk drives.

    PubMed

    Jing, Yang; Luo, Jianbin; Yang, Wenyan; Ju, Guoxian

    2004-11-01

    A new U-type micro-actuator for precisely positioning a magnetic head in high-density hard disk drives was proposed and developed. The micro-actuator is composed of a U-type stainless steel substrate and two piezoelectric ceramic elements. Using a high-d31 piezoelectric coefficient PMN-PZT ceramic plate and adopting reactive ion etching process fabricate the piezoelectric elements. Reliability against temperature was investigated to ensure the practical application to the drive products. The U-type substrate attached to each side via piezoelectric elements also was simulated by the finite-element method and practically measured by a laser Doppler vibrometer in order to testify the driving mechanics of it. The micro-actuator coupled with two piezoelectric elements featured large displacement of 0.875 microm and high-resonance frequency over 22 kHz. The novel piezoelectric micro-actuators then possess a useful compromise performance to displacement, resonance frequency, and generative force. The results reveal that the new design concept provides a valuable alternative for multilayer piezoelectric micro-actuators. PMID:15600092

  1. Lead-free Ba{sub 0.8}Ca{sub 0.2}(Zr{sub x}Ti{sub 1−x})O{sub 3} ceramics with large electrocaloric effect

    SciTech Connect

    Asbani, B.; Dellis, J.-L.; Lahmar, A.; Gagou, Y.; El Marssi, M.; Courty, M.; Djellab, K.; Amjoud, M.; Mezzane, D.; Kutnjak, Z.

    2015-01-26

    The electrocaloric effect was investigated in lead-free Zr doped Ba{sub 0.8}Ca{sub 0.2}(Zr{sub x}Ti{sub 1−x})O{sub 3} (BCTZ) ceramics synthesized by a conventional sintering process. Room-temperature x-ray diffraction analysis showed that the tetragonal structure is obtained in BCTZ for x ≤ 0.08 and a pseudo cubic phase for x > 0.08. The dielectric spectroscopy and calorimetry revealed that the Curie temperature decreases as a consequence of Zr doping and that the BCTZ exhibits a first order ferroelectric phase transition. The electrocaloric effect was determined by the calculation of the electrocaloric change of temperature (ΔT) using the Maxwell relation based on the P–E hysteresis loops measured at different temperatures. A large electrocaloric responsivity ΔT/ΔE = 0.34 × 10{sup −6 }Km/V was found for x = 0.04, which significantly exceeds of values found so far in other lead-free electrocaloric materials.

  2. Dielectric Properties of SrMnO3-doped K0.5Na0.5NbO3 Lead-Free Ceramics

    NASA Astrophysics Data System (ADS)

    Deng, Jianming; Sun, Xiaojun; Liu, Laijun; Liu, Saisai; Huang, Yanmin; Fang, Liang; Elouadi, Brahim

    2016-05-01

    (1-x)K0.5Na0.5NbO3-xSrMnO3 (0.02 ≤ x ≤ 0.08) (KNN-xSM) ceramics were fabricated by a conventional solid-state technique. X-ray diffraction of the samples revealed that the crystal structure changes from orthorhombic to tetragonal, and finally to pseudocubic symmetry with increasing x. Temperature dependence of dielectric properties showed that the temperature (T m) corresponding to the maximum of dielectric permittivity decreased with increasing x. Two dielectric relaxation processes occurred at high temperatures, which were attributed to grain and grain boundary responses, respectively. Polarization hysteresis loops (P-E) at different electrical fields were displayed. P rmax degenerated with the increase of SM due to the thermally activated leakage current increases. The relationship between electrical properties and defect compensation mechanism is discussed.

  3. Study of methods for automated crack inspection of electrically poled piezoelectric ceramics.

    SciTech Connect

    Yang, Pin; Hwang, Stephen C.; Jokiel, Bernhard, Jr.; Burns, George Robert

    2004-06-01

    The goal of this project was to identify a viable, non-destructive methodology for the detection of cracks in electrically poled piezoelectric ceramics used in neutron generator power supply units. The following methods were investigated: Impedance Spectroscopy, Scanning Acoustic Microscopy, Lock-in Thermography, Photo-acoustic Microscopy, and Scanned Vicinal Light. In addition to the exploration of these techniques for crack detection, special consideration was given to the feasibility of integrating these approaches to the Automatic Visual Inspection System (AVIS) that was developed for mapping defects such as chips, pits and voids in piezoelectric ceramic components. Scanned Vicinal Light was shown to be the most effective method of automatically detecting and quantifying cracks in ceramic components. This method is also very effective for crack detection in other translucent ceramics.

  4. Composition-driven phase boundary and electrical properties in (Ba0.94Ca0.06)(Ti1-xMx)O3 (M = Sn, Hf, Zr) lead-free ceramics.

    PubMed

    Zhao, Chunlin; Wang, Hui; Xiong, Jie; Wu, Jiagang

    2016-04-12

    In this study, we systematically investigated the composition dependence of the phase structure, microstructure, and electrical properties of (Ba0.94Ca0.06)(Ti1-xMx)O3 (M = Sn, Hf, Zr) ceramics synthesised by the conventional solid-state reaction method. The phase boundary type strongly depends on the composition, and then different electrical properties were exhibited. The addition of Hf and Zr can more quickly shift phase transition temperatures (TR-O and TO-T) to a higher temperature with respect to Sn, leading to the formation of different phase boundaries. In addition, different phase boundaries can also be affected by their doped contents. The R-O and O-T phase boundaries can be shown in the Sn-doped ceramics with x = 0.10, and the R-O phase boundary can exist in the Hf (x = 0.07) or Zr (x = 0.075)-doped ceramics. A high piezoelectric property of d33 = 600 pC N(-1) can be achieved in the Sn-doped ceramics due to the involvement of converging R-O/O-T phase boundaries, an enhanced ferroelectric performance with Pr = 14.54 μC cm(-2) and Ec = 1.82 kV cm(-1) can be attained in the Zr-doped ceramics, and Hf would benefit from obtaining a large strain behaviour (∼0.20%). We believe that the electrical properties and the related physical mechanisms of BaTiO3-based ceramics can be well unveiled by studying their chemical modification behavior. PMID:26952807

  5. Dielectric relaxation, lattice dynamics and polarization mechanisms in Bi0.5Na0.5TiO3-based lead-free ceramics

    NASA Astrophysics Data System (ADS)

    Viola, Giuseppe; Ning, Huanpo; Wei, Xiaojong; Deluca, Marco; Adomkevicius, Arturas; Khaliq, Jibran; John Reece, Michael; Yan, Haixue

    2013-07-01

    In 0.95[0.94Bi0.5Na0.5TiO3-0.06BaTiO3]-0.05CaTiO3 ceramics, the temperature TS (dielectric permittivity shoulder at about 125 °C) represents a transition between two different thermally activated dielectric relaxation processes. Below TS, the approximately linear decrease of the permittivity with the logarithm of frequency was attributed to the presence of a dominant ferroelectric phase. Above TS, the permittivity shows a more complicated dependence of the frequency and Raman modes indicate a sudden increase in the spatial disorder of the material, which is ascribed to the presence of a nonpolar phase and to a loss of interaction between polar regions. From 30 to 150 °C, an increase in the maximum polarization with increasing temperature was related to three possible mechanisms: polarization extension favoured by the simultaneous presence of polar and non-polar phases; the occurrence of electric field-induced transitions from weakly polar relaxor to ferroelectric polar phase; and the enhanced polarizability of the crystal structure induced by the weakening of the Bi-O bond with increasing temperature. The occurrence of different electric field induced polarization processes with increasing temperature is supported by the presence of additional current peaks in the current-electric field loops.

  6. Electro-caloric effect in lead-free Sn doped BaTiO{sub 3} ceramics at room temperature and low applied fields

    SciTech Connect

    Upadhyay, Sanjay Kumar; Reddy, V. Raghavendra E-mail: vrreddy@csr.res.in; Bag, Pallab; Rawat, R.; Gupta, S. M.; Gupta, Ajay

    2014-09-15

    Structural, dielectric, ferroelectric (FE), {sup 119}Sn Mössbauer, and specific heat measurements of polycrystalline BaTi{sub 1–x}Sn{sub x}O{sub 3} (x = 0% to 15%) ceramics are reported. Phase purity and homogeneous phase formation with Sn doping is confirmed from x-ray diffraction and {sup 119}Sn Mössbauer measurements. With Sn doping, the microstructure is found to change significantly. Better ferroelectric properties at room temperature, i.e., increased remnant polarization (38% more) and very low field switchability (225% less) are observed for x = 5% sample as compared to other samples and the results are explained in terms of grain size effects. With Sn doping, merging of all the phase transitions into a single one is observed for x ≥ 10% and for x = 5%, the tetragonal to orthorhombic transition temperature is found close to room temperature. As a consequence better electro-caloric effects are observed for x = 5% sample and therefore is expected to satisfy the requirements for non-toxic, low energy (field) and room temperature based applications.

  7. Electro-caloric effect in lead-free Sn doped BaTiO3 ceramics at room temperature and low applied fields

    NASA Astrophysics Data System (ADS)

    Upadhyay, Sanjay Kumar; Reddy, V. Raghavendra; Bag, Pallab; Rawat, R.; Gupta, S. M.; Gupta, Ajay

    2014-09-01

    Structural, dielectric, ferroelectric (FE), 119Sn Mössbauer, and specific heat measurements of polycrystalline BaTi1-xSnxO3 (x = 0% to 15%) ceramics are reported. Phase purity and homogeneous phase formation with Sn doping is confirmed from x-ray diffraction and 119Sn Mössbauer measurements. With Sn doping, the microstructure is found to change significantly. Better ferroelectric properties at room temperature, i.e., increased remnant polarization (38% more) and very low field switchability (225% less) are observed for x = 5% sample as compared to other samples and the results are explained in terms of grain size effects. With Sn doping, merging of all the phase transitions into a single one is observed for x ≥ 10% and for x = 5%, the tetragonal to orthorhombic transition temperature is found close to room temperature. As a consequence better electro-caloric effects are observed for x = 5% sample and therefore is expected to satisfy the requirements for non-toxic, low energy (field) and room temperature based applications.

  8. Comparative face-shear piezoelectric properties of soft and hard PZT ceramics

    NASA Astrophysics Data System (ADS)

    Miao, Hongchen; Chen, Xi; Cai, Hairong; Li, Faxin

    2015-12-01

    The face-shear ( d 36 ) mode may be the most practical shear mode in piezoelectrics, while theoretically this mode cannot appear in piezoelectric ceramics because of its transversally isotropic symmetry. Recently, we realized piezoelectric coefficient d 36 up to 206pC/N in soft PbZr1-xTixO3 (PZT) ceramics via ferroelastic domain engineering [H. C. Miao and F. X. Li, Appl. Phys. Lett. 107, 122902 (2015)]. In this work, we further realized the face-shear mode in both hard and soft PZT ceramics including PZT-4 (hard), PZT-51(soft), and PZT-5H (soft) and investigated the electric properties systematically. The resonance methods are derived to measure the d 36 coefficients using both square patches and narrow bar samples, and the obtained values are consistent with that measured by a modified d 33 meter previously. For all samples, the pure d 36 mode can only appear near the resonance frequency, and the coupled d 36 - d 31 mode dominates off resonance. It is found that both the piezoelectric coefficient d 36 and the electromechanical coupling factor k 36 of soft PZT ceramics (PZT-5H and PZT-51) are considerably larger than those of the hard PZT ceramics (PZT-4). The obtained d 36 of 160-275pC/N, k 36 ˜ 0.24, and the mechanical quality factor Q 36 of 60-90 in soft PZT ceramics are comparable with the corresponding properties of the d 31 mode sample. Therefore, the d 36 mode in modified soft PZT ceramics is more promising for industrial applications such as face-shear resonators and shear horizontal wave generators.

  9. Effect of Reoriented Nanodomains on Crystal Structure and Piezoelectric Properties of Polycrystalline Ferroelectric Ceramics

    NASA Astrophysics Data System (ADS)

    Fan, Qiaolan; Zeng, Weidong; Zhou, Changrong; Cen, Zhenyong; Yuan, Changlai; Xiao, Jianrong; Ma, Jiafeng

    2015-10-01

    It has been widely accepted that electric fields induce a reversible structural phase transition and thus yield giant piezoelectric responses in ferroelectric ceramics. Based on detailed measurements of polycrystalline (Li0.5Nd0.5)2+-modified 0.95Bi0.5Na0.5TiO3-0.05BaTiO3 ceramics, we demonstrate in this study that coherent diffraction from nanodomains in ferroelectric ceramics masks the real crystal structure. The observed electric-field-induced phase transformation behavior is a consequence of relaxor-to-ferroelectric transformation caused by changes in the coherence length of the nanodomains. A driving mechanism of the structure-property relationship in which high piezoelectric properties originate from correlated ordering of nanodomains during poling is proposed.

  10. Effect of lanthanum doping on the structural, ferroelectric, and strain properties of Bi1/2(Na0.82K0.18)1/2TiO3 lead-free ceramics

    NASA Astrophysics Data System (ADS)

    Dinh, Thi Hinh; Lee, Hyun-Young; Yoon, Chang-Ho; Malik, Rizwan Ahmed; Kong, Young-Min; Lee, Jae-Shin; Tran, Vu Diem Ngoc

    2013-04-01

    To clarify the effect of A-site donor doping on the phase transition and the strain enhancement, we investigated the crystal structure, as well as the piezoelectric, ferroelectric and electric-field-induced strain (EFIS) properties of La-doped Bi1/2(Na0.82K0.18)1/2TiO3 (BNKT) ceramics. Similarly to our previous studies on BNKT doped with B-site donors such as Nb and Ta, La doping was found to induce a ferroelectric-to-nonpolar (FE-NP) phase transition, leading to a large enhancement in EFIS just after the transition. The result provides strong evidence that a close relationship exists between the Goldschumidt's tolerance factor and the FE-NP transition in BNKT, which has been observed in B-site-donor or isovalent impurity-doped BNKT.

  11. Realization of face-shear piezoelectric coefficient d36 in PZT ceramics via ferroelastic domain engineering

    NASA Astrophysics Data System (ADS)

    Miao, Hongchen; Li, Faxin

    2015-09-01

    The piezoelectric face-shear ( d36 ) mode may be the most useful shear mode in piezoelectrics, while currently this mode can only exist in single crystals of specific point groups and cut directions. Theoretically, the d36 coefficient vanishes in piezoelectric ceramics because of its transversally isotropic symmetry. In this work, we modified the symmetry of poled PZT ceramics from transversally isotropic to orthogonal through ferroelastic domain switching by applying a high lateral stress along the "2" direction and holding the stress for several hours. After removing the compression, the piezoelectric coefficient d31 is found much larger than d32 . Then, by cutting the compressed sample along the Z x t 45 direction, we realized d36 coefficients up to 206 pC/N , which is measured by using a modified d33 meter. The obtained large d36 coefficients in PZT ceramics could be very promising for face-shear mode resonators and shear horizontal wave generation in nondestructive testing.

  12. Thermal depoling process and piezoelectric properties of bismuth sodium titanate ceramics

    NASA Astrophysics Data System (ADS)

    Hiruma, Yuji; Nagata, Hajime; Takenaka, Tadashi

    2009-04-01

    Stoichiometric and nonstoichiometric (Bi0.5Na0.5)TiO3 (BNT) ceramics were prepared by a conventional ceramic fabrication process. This study revealed that the high conductivity of BNT ceramics is associated with Bi vaporization during sintering. An x-ray study revealed that a tetragonal phase exists in the temperature range between 330 and 480 °C in BNT ceramic as well as BNT single crystals. In addition, the depolarization temperature Td, rhombohedral-tetragonal phase transition temperature TR-T, and the temperature Tm of the maximum dielectric constant were determined to be 187, approximately 300, and 325 °C, respectively, from the temperature dependences of dielectric properties using unpoled and poled specimens. The piezoelectric properties of all vibration modes and the temperature dependences of the piezoelectric properties were measured using fully poled BNT ceramics. It was also revealed that BNT ceramics exhibit three thermal depoling processes at Td, between Td and TR-T, and between TR-T and Tm from the effects of annealing on the field-induced strain, x-ray diffraction patterns, and dielectric constant of poled specimens.

  13. Dielectric and impedance spectroscopic studies of 0.8BaTiO3-0.2Bi0.5K0.5TiO3 lead-free ceramics

    NASA Astrophysics Data System (ADS)

    Ramesh, M. N. V.; Ramesh, K. V.

    2015-06-01

    0.8BaTiO3-0.2Bi0.5K0.5TiO3 (BT-BKT20) lead-free ceramics were prepared by conventional solid state reaction method followed by high energy ball milling. The formation of a single phase tetragonal structure in the material was confirmed by X-ray diffraction. Frequency and temperature-dependent dielectric studies show relaxor behavior in the BT-BKT20 which was found to obey modified Curie-Weiss law with degree of diffuseness 1.573. Complex impedance and electric modulus spectroscopy studies reveal temperature-dependent relaxation process in the material. The Cole-Cole plots were measured at high temperatures at which grain effect was observed. Impedance and electric modulus spectroscopy studies show non-Debye kind of conductivity relaxation process in the present material. Activation energies were calculated from impedance and electric modulus spectroscopy and the values of activation energy indicated that the conduction is ionic in nature. AC and DC conductivity have been measured and studied at different temperatures.

  14. Effect of cerium substitution on structural and impedance properties of 0.8Ba0.2(Bi0.5K0.5)TiO3 lead free ceramic system

    NASA Astrophysics Data System (ADS)

    Ramesh, M. N. V.; Ramesh, K. V.

    2016-01-01

    Cerium-doped 0.8BaTiO3-0.2Bi0.5K0.5TiO3 with composition 0.8Ba0.2(Bi0.5K0.5)Ti1-xCexO3 where x = 0.01, 0.02, 0.03, 0.04, 0.05, 0.06 lead free ceramics were prepared by conventional solid state reaction method followed by high energy ball milling. X-ray diffraction studies confirm the tetragonal structure at room temperature for all the Ce-doped samples. Lattice parameters and density were increasing with increase of Ce doping. Frequency and temperature dependent dielectric studies were carried out and indicate that the dielectric constant and Curie temperature are decreasing with increasing of Ce doping. All the Ce-doped samples exhibiting diffused and dispersive phase transitions with degree of diffuseness ranging from 1.4 to 2 calculated from the modified Curie-Weiss law. Impedance studies confirms the temperature dependent non-Debye kind of relaxation process in the material. From the Cole-Cole plots measured at high temperatures, reveals that the grain effect in the all Ce-doped samples. Impedance analysis studies also support the X-ray diffraction and dielectric studies that occupation of Ce both at A-site and B-site for small values of Ce doping.

  15. Composition-induced antiferroelectric phase and giant strain in lead-free (Nay,Biz)Ti1-xO3(1-x)-xBaTiO3 ceramics

    NASA Astrophysics Data System (ADS)

    Guo, Yiping; Gu, Mingyuan; Luo, Haosu; Liu, Yun; Withers, Ray L.

    2011-02-01

    (Nay,Biz)Ti1-xO3(1-x)-xBaTiO3 ceramics with an excess in Bi3+ and/or a deficiency in Na+ were prepared and investigated. It is found that an antiferroelectric phase can be induced through a modulation of the mole ratio of Na+ and Bi3+. A phase boundary between ferroelectric and antiferroelectric phases can be observed at ambient temperature. A modulated phase, which is the origin of relaxor antiferroelectric behavior, should be attributed to a compositional modulation. The antiferroelectric phase can be induced to the ferroelectric phase by an applied electric field. The stability of the induced ferroelectric phase strongly depends on the mole ratio of Na+ and Bi3+. A recoverable giant strain of 0.48% comparable to PbZrO3-based antiferroelectrics as well as electrostrictive coefficients (0.026 C4m-2) much higher than lead-based relaxor ferroelectrics with low-temperature dependence was achieved in (Nay,Biz)Ti1-xO3(1-x)-xBaTiO3 antiferroelectrics. Our results show there is a high possibility that the novel lead-free antiferroelectrics will replace the PbZrO3-based ones.

  16. Piezoelectric micromotor using a metal-ceramic composite structure.

    PubMed

    Koc, B; Bouchilloux, P; Uchino, K

    2000-01-01

    This paper presents a new piezoelectric micromotor design, in which a uniformly electroded piezoelectric ring bonded to a metal ring is used as the stator. Four inward arms at the inner circumference of the metal ring transfer radial displacements into tangential displacements. The rotor ends in a truncated cone shape and touches the tips of the arms. A rotation takes place by exciting coupled modes of the stator element, such as a radial mode and a second bending mode of the arms. The behavior of the free stator was analyzed using the ATILA finite element software. Torque vs. speed relationship was measured from the transient speed change with a motor load. A starting torque of 17 microNm was obtained at 20 Vrms. The main features of this motor are low cost and easy assembly because of a simple structure and small number of components. PMID:18238616

  17. Breakthrough: Lead-free Solder

    ScienceCinema

    Anderson, Iver

    2013-03-01

    Ames Laboratory senior metallurgist Iver Anderson explains the importance of lead-free solder in taking hazardous lead out of the environment by eliminating it from discarded computers and electronics that wind up in landfills. Anderson led a team that developed a tin-silver-copper replacement for traditional lead-tin solder that has been adopted by more than 50 companies worldwide.

  18. Lead-free primary explosives

    DOEpatents

    Huynh, My Hang V.

    2010-06-22

    Lead-free primary explosives of the formula (cat).sub.Y[M.sup.II(T).sub.X(H.sub.2O).sub.6-X].sub.Z, where T is 5-nitrotetrazolate, and syntheses thereof are described. Substantially stoichiometric equivalents of the reactants lead to high yields of pure compositions thereby avoiding dangerous purification steps.

  19. Breakthrough: Lead-free Solder

    SciTech Connect

    Anderson, Iver

    2012-01-01

    Ames Laboratory senior metallurgist Iver Anderson explains the importance of lead-free solder in taking hazardous lead out of the environment by eliminating it from discarded computers and electronics that wind up in landfills. Anderson led a team that developed a tin-silver-copper replacement for traditional lead-tin solder that has been adopted by more than 50 companies worldwide.

  20. High-frequency electromechanical properties of piezoelectric ceramic/polymer composites in broadband applications

    NASA Astrophysics Data System (ADS)

    Bowen, L. J.; Gururaja, T. R.

    1980-11-01

    Composites of piezoelectric ceramic (lead zirconate titanate) rods aligned in an epoxy resin matrix have been evaluated for broadband transducer applications. The rods are driven at their longitudinal mode resonance frequency and bandwidth is increased by fabricating the composite in a wedge configuration. The passband can be tailored as required by altering the surface profile of the device, and in principle bandwidths of almost 100 percent are possible. The attenuation properties of the polymer phase are of prime importance in mechanically decoupling adjacent piezoelectric elements. Acoustic signal attenuation in the polymer is accomplished by the series combination of acoustic impedence mismatch and classical transmission line attenuation. Experimental and theoretical considerations suggest the mechanical Q of the polymer is so low that the active elements are insignificantly damped. As a corollary, linear theory is not reliable for the prediction of dynamic mechanical properties of piezoelectric composites.

  1. Properties of PZT-Based Piezoelectric Ceramics Between -150 and 250 C

    NASA Technical Reports Server (NTRS)

    Hooker, Matthew W.

    1998-01-01

    The properties of three PZT-based piezoelectric ceramics and one PLZT electrostrictive ceramic were measured as a function of temperature. In this work, the dielectric, ferroelectric polarization versus electric field, and piezoelectric properties of PZT-4, PZT-5A, PZT-5H, and PLZT-9/65/35 were measured over a temperature range of -150 to 250 C. In addition to these measurements, the relative thermal expansion of each composition was measured from 25 to 600 C and the modulus of rupture of each material was measured at room temperature. This report describes the experimental results and compares and contrasts the properties of these materials with respect to their applicability to intelligent aerospace systems.

  2. Enhanced piezoelectric property of porous lead zirconate titanate ceramics with one dimensional ordered pore structure

    SciTech Connect

    Guo Rui; Wang Changan; Yang Ankun; Fu Juntao

    2010-12-15

    Lead zirconate titanate (PZT) ceramics with one dimensional ordered pore structure (1-3 type porous PZT ceramics) were fabricated in this study. The special structure not only enhanced the piezoelectric and dielectric properties effectively but also further decreased the acoustic impedance. All samples exhibited excellent piezoelectric properties despite high porosities. The d{sub 33} value was 608 pC /N (remained 88% that of dense PZT) when the porosity was up to 68.7%. The d{sub 33} value was 690 pC /N (same as dense PZT) when the porosity was 41.7%. The lowest acoustic impedance (Z) reached 1.3 MRayls. These results are promising for improving performance in hydrophones applications.

  3. Evaluation of Piezoelectric Ceramic Substrates for Ultrasonic Bulk Wave Filters and Resonators Using Pulse Interference Method

    NASA Astrophysics Data System (ADS)

    Kitamura, Takeshi; Kadota, Michio; Kasanami, Toru; Kushibiki, Jun-ichi; Chubachi, Noriyoshi

    1994-05-01

    In recent years, market demand has creared a need for high reproducibility in the frequency characteristics of piezoelectric ceramic filters and resonators that use the thickness extension mode. In order to increase this reproducibility, it is necessary mainly to improve accuracy in controlling the substrate thickness, and to reduce variations in elastic properties of substrate materials prior to the completion of products. The pulse interference method using longitudinal waves has been applied to the evaluation of piezoelectric ceramic substrates. A good correlation has been obtained between the interference frequencies, measured with this method, of substrates immediately after polishing and the frequency characteristics of completed products. It has been shown that this method is extremely useful for improving productivity of ultrasonic bulk-wave filters and resonators whose frequency characteristics directly depend upon the longitudinal wave velocities of substrate materials and their thicknesses.

  4. Understanding the role of A-site and B-site cations on piezoelectric instability in lead--free (1-x) BaTiO3 -- xA(Cu1/3Nb2/3)O3 (A = Sr, Ca, Ba) solid solutions

    NASA Astrophysics Data System (ADS)

    Maurya, Deepam; Zhou, Yuan; Priya, Shashank

    2013-03-01

    This study provides fundamental understanding of the enhanced piezoelectric instability in lead-free piezoelectric (1-x) BaTiO3-xA(Cu1/3Nb2/3) O3(A: Sr, Ba and Ca and x = 0.0-0.03) solid solutions. These compositions were found to exhibit large longitudinal piezoelectric constant (d33) of ~330 pC/N and electromechanical planar coupling constant (kp) ~ 46% at room temperature. The X-ray diffraction coupled with atomic pair distribution functions (PDF)s indicated increase in local polarization. Raman scattering and electron paramagnetic resonance (EPR) analysis revealed that substitutions on A and B-site both substantially perturbed the local octahedral dynamics and resulted in localized nano polar regions with lower symmetry. The presence of nano domains and local structural distortions smears the Curie peak resulting in diffuse order-disorder type phase transitions. The effect of these distortions on the variations in physical property was modeled and analyzed within the context of nanodomains and phase transitions. *spriya@vt.edu The financial support from National Science Foundation and Office of Basic Energy Science, Department of Energy (Microscopy analysis) is gratefully acknowledged. The authors would also like to acknowledge the support from KIMS (new piezoelectric)

  5. Optimum placement of piezoelectric ceramic modules for vibration suppression of highly constrained structures

    NASA Astrophysics Data System (ADS)

    Belloli, Alberto; Ermanni, Paolo

    2007-10-01

    The vibration suppression efficiency of so-called shunted piezoelectric systems is decisively influenced by the number, shape, dimensions and position of the piezoelectric ceramic elements integrated into the structure. This paper presents a procedure based on evolutionary algorithms for optimum placement of piezoelectric ceramic modules on highly constrained lightweight structures. The optimization loop includes the CAD software CATIA V5, the FE package ANSYS and DynOPS, a proprietary software tool able to connect the Evolving Object library with any simulation software that can be started in batch mode. A user-defined piezoelectric shell element is integrated into ANSYS 9.0. The generalized electromechanical coupling coefficient is used as the optimization objective. Position, dimensions, orientation, embedding location in the composite lay-up and wiring of customized patches are determined for optimum vibration suppression under consideration of operational and manufacturing constraints, such as added mass, maximum strain and requirements on the control circuit. A rear wing of a racing car is investigated as the test object for complex, highly constrained geometries.

  6. Dielectric, piezoelectric, and electromechanical phenomena in (K0.5Na0.5)NbO3-LiNbO3-BiFeO3-SrTiO3 ceramics

    NASA Astrophysics Data System (ADS)

    Li, Enzhu; Suzuki, Ryo; Hoshina, Takuya; Takeda, Hiroaki; Tsurumi, Takaaki

    2009-03-01

    The effect of the substitutions of BiFeO3 (BF) and SrTiO3 (ST) to (Na0.5K0.5)NbO3-LiNbO3 (KNN-LN) ceramics was studied as a candidate of lead-free piezoceramics. The piezoelectric property is enhanced near the phase transition composition caused by the distortion of crystal lattice by Li+ and also the strong ferroelectric nature of BF. The ST was found to be effective in improving the temperature dependence of the KNN ceramics. Small amount of ST also promoted the incorporation of LN and BF into the crystal lattice, and enhanced the piezoelectric performance furthermore. The 94.5(Na0.5K0.5)NbO3-4.5LiNbO3-0.5SrTiO3-0.5BiFeO3 ceramics showed excellent piezoelectric properties of d15=231 pC/N, d33=155 pC/N, and d31=70 pC/N.

  7. Dielectric, piezoelectric, and ferroelectric properties of lanthanum-modified PZTFN ceramics

    NASA Astrophysics Data System (ADS)

    Kumar, Arvind; Mishra, S. K.

    2014-10-01

    Specimens of Pb1-1.5 x La x (Zr0.53Ti0.47)1- y- z Fe y Nb z O3 ( x = 0, 0.004, 0.008, 0.012, and 0.016, y = z = 0.01) (PZTFN) ceramics were synthesized by a semi-wet route. In the present study, the effect of La doping was investigated on the structural, microstructural, dielectric, piezoelectric, and ferroelectric properties of the ceramics. The results show that, the tetragonal (space group P4 mm) and rhombohedral (space group R3 c) phases are observed to coexist in the sample at x = 0.012. Microstructural investigations of all the samples reveal that La doping inhibits grain growth. Doping of La into PZTFN improves the dielectric, ferroelectric, and piezoelectric properties of the ceramics. The hysteresis loops of all specimens exhibit nonlinear behavior. The dielectric, piezoelectric and ferroelectric properties show a maximum response at x ≥ 0.012, which corresponds to the morphotropic phase boundary (MPB).

  8. Effect of (Mn, F) and (Mg, F) co-doping on dielectric and piezoelectric properties of lead zirconate titanate ceramics

    NASA Astrophysics Data System (ADS)

    Boucher, E.; Guyomar, D.; Lebrun, L.; Guiffard, B.; Grange, G.

    2002-11-01

    The influence of (Mn, F) and (Mg, F) dopants on the piezoelectric properties of lead zirconate titanate (PZT) ceramic compositions close to the morphotropic phase boundary is investigated. PZT ceramics are prepared by a chemical route based on co-precipitation of oxalates and hydroxides. The acceptor is incorporated into the B site of the materials and the fluorine ion is introduced into anionic sites. The d33 coefficient, the mechanical quality factor Qm and other properties are measured. Scanning electron microscopy is used to determine the grain size of the materials. Electron spin resonance is used to determine the valency state of Mn in fluorinated PZT ceramics. In Mn doped PZT, the introduction of a fluorine ion makes the poling process easier and increases the piezoelectric coefficients whereas the fluorination of Mg doped PZT constantly leads to hard materials with a lower piezoelectric response. This study shows that (Mn, F) co-doping produces semihard materials with high piezoelectric coefficients.

  9. Research on key technique of microscopy three-dimensional image reconstruction based on piezoelectric ceramics

    NASA Astrophysics Data System (ADS)

    Wang, Jianhua; Xiao, Zexin

    2011-11-01

    Due to the limited depth of focus of microscope objective, a series of images taken from different sections and directions are needed to reconstruct 3D microscopy image. In this paper, we present a novel method which utilizes piezoelectric actuator, high magnification microscopy system without mirror and single CCD to observe micro-objects and reconstruct its three-dimensional image. Inverse piezoelectric effect of piezoelectric ceramics have some superior characteristics, such as high positioning resolution, high positioning accuracy, etc. And piezoelectric actuator possess the advantage of small-size, strong-power and easy- to-integrated as well. Based on these points, we designed a 360° rotation and tilt positioning platform. In this platform, Piezoelectric actuator is employed to ensure the positioning accuracy at axis-Z direction. At the same time, Motion of 360° rotation and tilt can be controlled precisely using stepping motor controlling technology. Furthermore, finite element methods (FEM) analyze software--ANSYS is used to analyze the rigidity, stress and structure optimization of the platform. This rotation and tilt mechanical positioning platform can help the single CCD to get clear, complete-view two dimensional images. This method paves the way for three-dimensional reconstruction of micro objects. Experiments demonstrate that this 360° rotation and tilt positioning stage is structure-simple and high-accurate. It can be widely used in micro-structure observing and three-dimensional image reconstruction among mechanics, materials and biology, etc.

  10. Excitation of fundamental shear horizontal wave by using face-shear (d36) piezoelectric ceramics

    NASA Astrophysics Data System (ADS)

    Miao, Hongchen; Dong, Shuxiang; Li, Faxin

    2016-05-01

    The fundamental shear horizontal (SH0) wave in plate-like structures is extremely useful for non-destructive testing (NDT) and structural health monitoring (SHM) as it is non-dispersive. However, currently, the SH0 wave is usually excited by electromagnetic acoustic transducers (EMAT) whose energy conversion efficiency is fairly low. The face-shear ( d 36 ) mode piezoelectrics is more promising for SH0 wave excitation, but this mode cannot appear in conventional piezoelectric ceramics. Recently, by modifying the symmetry of poled PbZr1-xTixO3 (PZT) ceramics via ferroelastic domain engineering, we realized the face-shear d 36 mode in both soft and hard PZT ceramics. In this work, we further improved the face-shear properties of PZT-4 and PZT-5H ceramics via lateral compression under elevated temperature. It was found that when bonded on a 1 mm-thick aluminum plate, the d 36 type PZT-4 exhibited better face-shear performance than PZT-5H. We then successfully excite SH0 wave in the aluminum plate using a face-shear PZT-4 square patch and receive the wave using a face-shear 0.72[Pb(Mg1/3Nb2/3)O3]-0.28[PbTiO3] (PMN-PT) patch. The frequency response and directionality of the excited SH0 wave were also investigated. The SH0 wave can be dominated over the Lamb waves (S0 and A0 waves) from 160 kHz to 280 kHz. The wave amplitude reaches its maxima along the two main directions (0° and 90°). The amplitude can keep over 80% of the maxima when the deviate angle is less than 30°, while it vanishes quickly at the 45° direction. The excited SH0 wave using piezoelectric ceramics could be very promising in the fields of NDT and SHM.

  11. Phase transitional behavior and piezoelectric properties of (Na{sub 0.5}K{sub 0.5})NbO{sub 3}-LiNbO{sub 3} ceramics

    SciTech Connect

    Guo Yiping; Kakimoto, Ken-ichi; Ohsato, Hitoshi

    2004-11-01

    Lead-free piezoelectric ceramics (1-x)(Na{sub 0.5}K{sub 0.5})NbO{sub 3}-xLiNbO{sub 3} {l_brace}[Li{sub x}(Na{sub 0.5}K{sub 0.5}){sub 1-x}]NbO{sub 3}{r_brace} (x=0.04-0.20) have been synthesized by an ordinary sintering technique. The materials with perovskite structure is orthorhombic phase at x{<=}0.05 and becomes tetragonal phase at x{>=}0.07, a phase K{sub 3}Li{sub 2}Nb{sub 5}O{sub 15} with tetragonal tungsten bronze structure begins to appear at x=0.08 and becomes dominant with increasing the content of LiNbO{sub 3}. A morphotropic phase boundary between orthorhombic and tetragonal phases is found in the composition range 0.05piezoelectric and electromechanical properties are enhanced for compositions near the morphotropic phase boundary. Piezoelectric constant d{sub 33} values reach 200-235 pC/N. Electromechanical coefficients of the planar mode and the thickness mode reach 38%-44% and 44%-48%, respectively. The Curie temperatures (T{sub C}) of [Li{sub x}(Na{sub 0.5}K{sub 0.5}){sub 1-x}]NbO{sub 3} (x=0.04-0.20) are in the range of 452-510 deg. C, at least 100 deg. C higher than that of conventional Pb(Zr,Ti)O{sub 3}. Our results show that [Li{sub x}(Na{sub 0.5}K{sub 0.5}){sub 1-x}]NbO{sub 3} is a good lead-free high-temperature piezoelectric ceramic.

  12. Improved ferroelectric/piezoelectric properties and bright green/UC red emission in (Li,Ho)-doped CaBi4Ti4O15 multifunctional ceramics with excellent temperature stability and superior water-resistance performance.

    PubMed

    Xiao, Ping; Guo, Yongquan; Tian, Mijie; Zheng, Qiaoji; Jiang, Na; Wu, Xiaochun; Xia, Zhiguo; Lin, Dunmin

    2015-10-21

    Multifunctional materials based on rare earth ion doped ferro/piezoelectrics have attracted considerable attention in recent years. In this work, new lead-free multifunctional ceramics of Ca1-x(LiHo)x/2Bi4Ti4O15 were prepared by a conventional solid-state reaction method. The great multi-improvement in ferroelectricity/piezoelectricity, down/up-conversion luminescence and temperature stability of the multifunctional properties is induced by the partial substitution of (Li0.5Ho0.5)(2+) for Ca(2+) ions in CaBi4Ti4O15. All the ceramics possess a bismuth-layer structure, and the crystal structure of the ceramics is changed from a four layered bismuth-layer structure to a three-layered structure with the level of (Li0.5Ho0.5)(2+) increasing. The ceramic with x = 0.1 exhibits simultaneously, high resistivity (R = 4.51 × 10(11)Ω cm), good piezoelectricity (d33 = 10.2 pC N(-1)), high Curie temperature (TC = 814 °C), strong ferroelectricity (Pr = 9.03 μC cm(-2)) and enhanced luminescence. These behaviours are greatly associated with the contribution of (Li0.5Ho0.5)(2+) in the ceramics. Under the excitation of 451 nm light, the ceramic with x = 0.1 exhibits a strong green emission peak centered at 545 nm, corresponding to the transition of the (5)S2→(5)I8 level in Ho(3+) ions, while a strong red up-conversion emission band located at 660 nm is observed under the near-infrared excitation of 980 nm at room temperature, arising from the transition of (5)F5→(5)I8 levels in Ho(3+) ions. Surprisingly, the excellent temperature stability of ferroelectricity/piezoelectricity/luminescence and superior water-resistance behaviors of piezoelectricity/luminescence are also obtained in the ceramic with x = 0.1. Our study suggests that the present ceramics may have potential applications in advanced multifunctional devices at high temperature. PMID:26387782

  13. Detection of cancer biomarkers by piezoelectric biosensor using PZT ceramic resonator as the transducer.

    PubMed

    Su, Li; Zou, Lan; Fong, Chi-Chun; Wong, Wing-Leung; Wei, Fan; Wong, Kwok-Yin; Wu, Rudolf S S; Yang, Mengsu

    2013-08-15

    A novel piezoelectric biosensor using lead titanate zirconate (PZT) ceramic resonator as transducer was developed for label-free, cost-effective, and direct detection of cancer biomarkers. We designed a dual sensing scheme where two ceramic resonators were connected in parallel, in which one resonator was used as the sensing unit and the other as the control unit, in order to minimize environment influences including temperature fluctuation and to achieve the required frequency stability for biosensing applications. Detection of selected cancer biomarkers, such as prostate specific antigen (PSA) and ?-fetoprotein (AFP) was carried out to evaluate the performance of the biosensor. The device showed high sensitivity (0.25 ng/ml) and fast detection (within 30 min) with small amount of sample (1 ?l), which is compatible to that required by clinical measurements. The results also showed that the ceramic resonator-based piezoelectric biosensor platform could be utilized with different chemical interfaces, and the miniaturized size of the ceramic resonators makes it suitable for fabricating sensor arrays for multiplex detection. PMID:23542085

  14. Hierarchical domain structure of lead-free piezoelectric (Na1/2 Bi1/2)TiO3-(K1/2 Bi1/2)TiO3 single crystals

    NASA Astrophysics Data System (ADS)

    Luo, Chengtao; Wang, Yaojin; Ge, Wenwei; Li, Jiefang; Viehland, Dwight; Delaire, Olivier; Li, Xiaobin; Luo, Haosu

    2016-05-01

    We report a unique hierarchical domain structure in single crystals of (Na1/2Bi1/2)TiO3-xat. %(K1/2Bi1/2)TiO3 for x = 5 and 8 by transmission electron microscopy (TEM). A high density of polar nano-domains with a lamellar morphology was found, which were self-assembled into a quadrant-like configuration, which then assembled into conventional ferroelectric macro-domains. Studies by high resolution TEM revealed that the polar lamellar regions contained a coexistence of in-phase and anti-phase oxygen octahedral tilt regions of a few nanometers in size. Domain frustration over multiple length scales may play an important role in the stabilization of the hierarchy, and in reducing the piezoelectric response of this Pb-free piezoelectric solid solution.

  15. Hot-stage transmission electron microscopy study of (Na, K)NbO{sub 3} based lead-free piezoceramics

    SciTech Connect

    Lu, Shengbo; Xu, Zhengkui; Kwok, K. W.; Chan, Helen L. W.

    2014-07-28

    Hierarchical nanodomains assembled into micron-sized stripe domains, which is believed to be associated with outstanding piezoelectric properties, were observed at room temperature in a typical lead free piezoceramics, (Na{sub 0.52}K{sub 0.48−x})(Nb{sub 0.95−x}Ta{sub 0.05})-xLiSbO{sub 3}, with finely tuned polymorphic phase boundaries (x = 0.0465) by transmission electron microscopy. The evolution of domain morphology and crystal structure under heating and cooling cycles in the ceramic was investigated by in-situ hot stage study. It is found that the nanodomains are irreversibly transformed into micron-sized rectangular domains during heating and cooling cycles, which lead to the thermal instability of piezoelectric properties of the materials.

  16. Orientation-dependent piezoelectric properties in lead-free epitaxial 0.5BaZr{sub 0.2}Ti{sub 0.8}O{sub 3}-0.5Ba{sub 0.7}Ca{sub 0.3}TiO{sub 3} thin films

    SciTech Connect

    Luo, B. C.; School of Science, Northwestern Polytechnical University, Xi'an 710072 ; Wang, D. Y.; Li, S.; Duan, M. M.

    2013-09-16

    Orientation-engineered 0.5BaZr{sub 0.2}Ti{sub 0.8}O{sub 3}-0.5Ba{sub 0.7}Ca{sub 0.3}TiO{sub 3} (BZT-BCT) thin films were deposited on La{sub 0.7}Sr{sub 0.3}MnO{sub 3}-coated SrTiO{sub 3} single-crystalline (001), (110), and (111) substrates by off-axis radio-frequency magnetron sputtering. X-ray diffraction confirmed a highly epitaxial growth of all the as-deposited films. It is believed the strong orientation dependence of ferroelectric and piezoelectric properties on the films is attributed to the relative alignment of crystallites and spontaneous polarization vector. The optimal ferroelectric response lies in the [001] direction, whereas a comparatively large effective piezoelectric coefficient d{sub 33,eff} of 100.1 ± 5 pm/V was attained in [111] BZT-BCT thin film, suggesting its potential application for high-performance lead-free piezoelectric devices.

  17. Piezoelectric Resonance Characteristics of SrBi2Nb2O9-based Ceramics

    NASA Astrophysics Data System (ADS)

    Ando, Akira; Kimura, Masahiko; Sakabe, Yukio

    2003-01-01

    Piezoelectric resonance characteristics of SrBi2Nb2O9-based ceramics were studied for thickness-extensional (TE) and thickness-shear (TS) vibration modes. A resonator with a double-layer structure was also prepared with a co-firing technique to generate the second harmonics of TE (TE2) vibration mode. Single mode resonance characteristics are realized for TS mode vibration and the third harmonic TE (TE3) mode vibration on an SBN single plate. The double-layer-structure resonator also shows a good single mode resonance characteristic for the TE2 mode. This TE2 mode resonator has superior advantages in terms of piezoelectric resonant characteristics, compared to other single mode resonators such as the TS- or TE3-mode resonator.

  18. Enhanced ferroelectric and piezoelectric response in Mn-doped Bi0.5Na0.5TiO3-BaTiO3 lead-free film by pulsed laser deposition

    NASA Astrophysics Data System (ADS)

    Jin, Chengchao; Wang, Feifei; Leung, Chung Ming; Yao, Qirong; Tang, Yanxue; Wang, Tao; Shi, Wangzhou

    2013-10-01

    Mn-doped Bi0.5Na0.5TiO3-BaTiO3 thin film with the composition around the morphotropic phase boundary was grown on Pt-electrodized Si substrate by pulsed laser deposition. Highly (1 0 0)-oriented film with pure perovskite structure was obtained through carefully controlling the growth conditions. Well-defined ferroelectric P-E loop was obtained with the average remnant polarization Pr and coercive field Ec of ∼11.3 μC/cm2 and ∼6.5 kV/mm, respectively. Polycrystalline structures and multidomain states were revealed by piezoresponse force microscopy and large local strain response was obtained with the normalized strain Smax/Emax up to 92 pm/V. The excellent global electrical properties make it quite promising in environmental-friendly ferroelectric and piezoelectric devices.

  19. Re-poling process for piezoelectric-based multilayer ceramic capacitors force sensor

    NASA Astrophysics Data System (ADS)

    Lin, Keng-Ren; Chang, Chih-Han; Chiang, Cheng-Hung; Lin, Che-Hsin

    2013-04-01

    This study presents an industrial-grade piezoelectric-based multilayer ceramic capacitors (MLCCs) force sensor. In order to increase the sensitivity and reduce the variation of different MLCCs, a simple re-poling process is adopted by applying an external electric field at the Curie temperature of MLCCs. Results indicate that the re-poling treatment improved up to 100-fold for the force detection sensitivity and reduced the variation for the output force response by 10-fold in comparison with the MLCC sensors without re-poling.

  20. Piezoelectric performances of undoped ( K , Na ) NbO3 ceramics and crystals for transducers applications

    NASA Astrophysics Data System (ADS)

    Bah, Micka; Giovannelli, Fabien; Schoenstein, Frédéric; Retoux, Richard; Feuillard, Guy; Le Clézio, Emmanuel; Monot-Laffez, Isabelle

    2014-11-01

    The aim of this work is to take control on the grain size and densification of undoped K0.5Na0.5NbO3 (KNN), from micrometer to millimeter grain sizes. For this purpose, ceramics are prepared by spark plasma sintering (SPS) and conventional sintering. Their piezoelectric properties are comparatively studied. After full structural and microstructural characterizations, high electromechanical properties (kt = 45 %, kp = 30 %, Z = 20 MRay) for conventional sintering and (kt = 45 %, kp = 48 %, Z = 30 MRay) for SPS sintering are obtained. Otherwise, millimeter grains are produced by the floating zone method used for crystal growth, and their electromechanical properties are determined and compared to their homologous ceramics. Moreover, using the characteristics of the three materials, simulated electroacoustic responses of single-element transducers are compared. The results show that KNN is suitable for transducer applications.

  1. Effect of Different Mn-doping Types on BLFG-PT High-temperature Piezoelectric Ceramics

    NASA Astrophysics Data System (ADS)

    Jin, Guoxi; Chen, Jianguo; Dai, Rui; Zhang, Haiyan; Cheng, Jinrong

    Mn-doped 0.63(Bi0.94La0.06)(Fe0.95Ga0.05)-0.37PbTiO3 ceramics with exactly stoichiometric ratio in lattice for substituting Ti-site induced large microstructure distortion and internal stress. However, for the specimens of Mn introduction as sintering aids, distinct relaxation characteristic transforming from pure BLFG-PT can be obtained. Moreover, little difference could be classified according to the selected raw materials of MnCO3 and MnO2 on the properties of BLFG-PT ceramics. They both could effectively improve the density and make the high-temperature phase transition become more diffused, revealing relaxor ferroelectrics characteristic. In addition, all the Mn-doped samples, greatly decreased dielectric loss were observed which indicates the potential use of Mn-doping in high power piezoelectric device application and modification.

  2. A Piezoelectric PZT Ceramic Mulitlayer Stack for Energy Harvesting Under Dynamic Forces

    NASA Technical Reports Server (NTRS)

    Xu, Tian-Bing; Siochi, Emilie J.; Kang, Jin Ho; Zuo, Lei; Zhou, Wanlu; Tang, Xiudong; Jiang, Xiaoning

    2011-01-01

    Piezoelectric energy harvesting transducers (PEHTs) are commonly used in motion/vibration energy scavenging devices. To date, most researchers have focused on energy harvesting at narrow bandwidths around the mechanical resonance frequency, and most piezoelectric harvesting devices reported in the literature have very low effective piezoelectric coefficient (d(sub eff)) (< 10(exp 4) pC/N). For instance, more than 80% of PEHT related papers are on transverse "31" mode cantilever beam type PEHTs (CBPEHTs) having piezoelectric coefficients of about 100 pC/N. The level of harvested electrical power for CBPEHTs is on the order of microW even at resonance mode. In order to harvest more electrical energy across broader bandwidth, high effective piezoelectric coefficient structures are needed. In this study, we investigate a "33" longitudinal mode, piezoelectric PZT ceramic multilayer stack (PZT-Stack) with high effective piezoelectric coefficient for high-performance PEHTs. The PZT-Stack is composed of 300 layers of 0.1 mm thick PZT plates, with overall dimensions of 32.4 mm X 7.0 mm X 7.0 mm. Experiments were carried out with dynamic forces in a broad bandwidth ranging from 0.5 Hz to 25 kHz. The measured results show that the effective piezoelectric coefficient of the PZT-stack is about 1 X 10(exp 5) pC/N at off-resonance frequencies and 1.39 X 10(exp 6) pC/N at resonance, which is order of magnitude larger than that of traditional PEHTs. The effective piezoelectric coefficients (d(sub eff)) do not change significantly with applied dynamic forces having root mean square (RMS) values ranging from 1 N to 40 N. In resonance mode, 231 mW of electrical power was harvested at 2479 Hz with a dynamic force of 11.6 N(sub rms), and 7.6 mW of electrical power was generated at a frequency of 2114 Hz with 1 N(sub rms) dynamic force. In off-resonance mode, an electrical power of 18.7 mW was obtained at 680 Hz with a 40 N(sub rms) dynamic force. A theoretical model of energy harvesting for the PZT-Stack is established. The modeled results matched well with experimental measurements. This study demonstrated that high effective piezoelectric coefficient structures enable PEHTs to harvest more electrical energy from mechanical vibrations or motions, suggesting an effective design for high-performance low-footprint PEHTs with potential applications in military, aerospace, and portable electronics. In addition, this study provides a route for using piezoelectric multilayer stacks for active or semi-active adaptive control to damp, harvest or transform unwanted dynamic vibrations into useful electrical energy.

  3. Phase transitions and the piezoelectricity around morphotropic phase boundary in Ba(Zr0.2Ti0.8)O3-x(Ba0.7Ca0.3)TiO3 lead-free solid solution

    NASA Astrophysics Data System (ADS)

    Zhang, Le; Zhang, Ming; Wang, Liang; Zhou, Chao; Zhang, Zhen; Yao, Yonggang; Zhang, Lixue; Xue, Dezhen; Lou, Xiaojie; Ren, Xiaobing

    2014-10-01

    In this paper, two displacive phase transitions around the morphotropic phase boundary (MPB) in Ba(Zr0.2Ti0.8)O3-x(Ba0.7Ca0.3)TiO3 (BZT-xBCT) ceramics were detected by inspecting two anomalies of the Raman Ti4+-O2- longitudinal optical mode (˜725 cm-1). Further, permittivity and X-ray diffraction results demonstrated these two phase transitions originate from tetragonal (T) to rhombohedral (R) through an intermediate orthorhombic (O) phase. Importantly, we found that the maximum piezoelectric response (d33 = 545pC/N) was achieved at the boundary between the T and O phase, indicating that the giant piezoelectricity of BZT-xBCT may mainly stem from the T-O phase boundary due to easier polarization rotation and larger lattice softening.

  4. Lead-free electric matches.

    SciTech Connect

    Son, S. F.; Hiskey, M. A.; Naud, D.; Busse, J. R.; Asay, B. W.

    2002-01-01

    Electric matches are used in pyrotechnics to initiate devices electrically rather than by burning fuses. Fuses have the disadvantage of burning with a long delay before igniting a pyrotechnic device, while electric matches can instantaneously fire a device at a user's command. In addition, electric matches can be fired remotely at a safe distance. Unfortunately, most current commercial electric match compositions contain lead as thiocyanate, nitroresorcinate or tetroxide, which when burned, produces lead-containing smoke. This lead pollutant presents environmental exposure problems to cast, crew, and audience. The reason that these lead containing compounds are used as electric match compositions is that these mixtures have the required thermal stability, yet are simultaneously able to be initiated reliably by a very small thermal stimulus. A possible alternative to lead-containing compounds is nanoscale thermite materials (metastable intermolecular composites or MIC). These superthermite materials can be formulated to be extremely spark sensitive with tunable reaction rate and yield high temperature products. We have formulated and manufactured lead-free electric matches based on nanoscale Al/MoO{sub 3} mixtures. We have determined that these matches fire reliably and to consistently ignite a sample of black powder. Initial safety, ageing and performance results are presented in this paper.

  5. Development of lead-free single-element ultrahigh frequency (170-320MHz) ultrasonic transducers.

    PubMed

    Lam, Kwok Ho; Ji, Hong Fen; Zheng, Fan; Ren, Wei; Zhou, Qifa; Shung, K Kirk

    2013-07-01

    This paper presents the design, fabrication and characterization of single-element ultrahigh frequency (UHF) ultrasonic transducers in which the center frequency ranged from 170 to 320MHz. The center frequency of >300MHz is the highest value of lead-free ceramic ultrasonic transducers ever reported. With concern in the environmental pollution of lead-based materials, the transducer elements presented in this work were lead-free K0.5Na0.5NbO3/Bi0.5Na0.5TiO3 (KNN/BNT) composite thick films. All transducers were evaluated in a pulse-echo arrangement. The measured -6dB bandwidth of the transducers ranged from 35% to 64%. With the optimized piezoelectric properties of the composite film, the insertion loss of the UHF transducers was measured and determined to range from -50 to -60dB. In addition to the pulse-echo measurement, a 6?m tungsten wire phantom was also imaged with a 205MHz transducer to demonstrate the imaging capability. The measured -6dB axial and lateral resolutions were found to be 12?m and 50?m, respectively. The transducer performance presented in this work is shown to be better or comparable to previously reported results even though the frequency is much higher. PMID:23485349

  6. Polar nanoregions and dielectric properties in high-strain lead-free 0.93(Bi{sub 1/2}Na{sub 1/2})TiO{sub 3}-0.07BaTiO{sub 3} piezoelectric single crystals

    SciTech Connect

    Chen, Cheng-Sao; Chen, Pin-Yi; Tu, Chi-Shun

    2014-01-07

    A structural coexistence of rhombohedral (R) and tetragonal (T) phases has been revealed in the (001){sub c}-cut lead-free 0.93(Bi{sub 1/2}Na{sub 1/2})TiO{sub 3}–0.07BaTiO{sub 3} (BNB7T) piezoelectric crystals, which grown by the self-flux method, in the lower temperatures by high-resolution synchrotron X-ray diffraction, reciprocal space mapping, and transmission electron microscopy. The dielectric permittivity exhibits a thermal hysteresis in the region of 120–260 °C, implying a first-order-like phase transition from R+T to T. The real part (ε′) of dielectric permittivity begins to deviates from the Curie-Weiss equation, ε′ = C/(T − T{sub o}), from the Burns temperature T{sub B} = 460 °C, below which the polar nanoregions (or nanoclusters) develop and attenuate dielectric responses. The polar nanoregions of 5–10 nm were revealed by high-resolution transmission electron microscope. The normal piezoelectric coefficient d{sub 33} exhibits a rapid increase at E = 15–20 kV/cm and reaches a maximum of d{sub 33} ∼450 pC/N. The high piezoelectric response and E-field induced strain in BNB7T single crystals can be attributed to structural phase transitions under an E-field application.

  7. Dielectric, ferroelectric and piezoelectric properties of La-modified PCT ceramics

    NASA Astrophysics Data System (ADS)

    Singh, Sarabjit; Thakur, O. P.; Prakash, Chandra; Raina, K. K.

    2005-12-01

    Polycrystalline samples of lanthanum-modified PCT ceramics with composition Pb 0.76-3x/2La xCa 0.24Mn 0.02Ti 0.98O 3 (PLCT); x=0-0.08 (in steps of 0.02) were prepared by using conventional dry ceramic technique. Samples were sintered at 1150 C. X-ray analysis confirmed the formation of single-phase compound with tetragonal crystal structure. Dielectric properties were studied in detail as a function of frequency and temperature. From temperature variation of dielectric constant, Curie temperature ( Tc) was determined. Discussion on hysteresis behaviour for all the samples at room temperature is presented. Dielectric constant at room temperature shows an increasing trend and Curie temperature shows decreasing trend with the increase in lanthanum in PCT ceramics. Curie temperature determined from thermal expansion behaviour of sintered samples was found to be in good agreement with that determined from dielectric studies. Piezoelectric properties show a significant improvement with lanthanum substitution.

  8. Domain wall motion and electromechanical strain in lead-free piezoelectrics: Insight from the model system (1 - x)Ba(Zr0.2Ti0.8)O3-x(Ba0.7Ca0.3)TiO3 using in situ high-energy X-ray diffraction during application of electric fields

    SciTech Connect

    Tutuncu, Goknur; Li, Binzhi; Bowman, Keith; Jones, Jacob L.

    2014-07-17

    The piezoelectric compositions (1 - x)Ba(Zr0.2Ti0.8)O3–x(Ba0.7Ca0.3)TiO3 (BZT-xBCT) span a model lead-free morphotropic phase boundary (MPB) between room temperature rhombohedral and tetragonal phases at approximately x = 0.5. In the present work, in situ X-ray diffraction measurements during electric field application are used to elucidate the origin of electromechanical strain in several compositions spanning the tetragonal compositional range 0.6 ≤ x ≤ 0.9. As BCT concentration decreases towards the MPB, the tetragonal distortion (given by c/a-1) decreases concomitantly with an increase in 90° domain wall motion. The increase in observed macroscopic strain is predominantly attributed to the increased contribution from 90° domain wall motion. The results demonstrate that domain wall motion is a significant factor in achieving high strain and piezoelectric coefficients in lead-free polycrystalline piezoelectrics.

  9. Domain wall motion and electromechanical strain in lead-free piezoelectrics: Insight from the model system (1 − x)Ba(Zr{sub 0.2}Ti{sub 0.8})O{sub 3}–x(Ba{sub 0.7}Ca{sub 0.3})TiO{sub 3} using in situ high-energy X-ray diffraction during application of electric fields

    SciTech Connect

    Tutuncu, Goknur; Li, Binzhi; Bowman, Keith; Jones, Jacob L.

    2014-04-14

    The piezoelectric compositions (1 − x)Ba(Zr{sub 0.2}Ti{sub 0.8})O{sub 3}–x(Ba{sub 0.7}Ca{sub 0.3})TiO{sub 3} (BZT-xBCT) span a model lead-free morphotropic phase boundary (MPB) between room temperature rhombohedral and tetragonal phases at approximately x = 0.5. In the present work, in situ X-ray diffraction measurements during electric field application are used to elucidate the origin of electromechanical strain in several compositions spanning the tetragonal compositional range 0.6 ≤ x ≤ 0.9. As BCT concentration decreases towards the MPB, the tetragonal distortion (given by c/a-1) decreases concomitantly with an increase in 90° domain wall motion. The increase in observed macroscopic strain is predominantly attributed to the increased contribution from 90° domain wall motion. The results demonstrate that domain wall motion is a significant factor in achieving high strain and piezoelectric coefficients in lead-free polycrystalline piezoelectrics.

  10. Three-degree-of-freedom ultrasonic motor using a 5-mm-diameter piezoelectric ceramic tube.

    PubMed

    Mingsen Guo; Junhui Hu; Hua Zhu; Chunsheng Zhao; Shuxiang Dong

    2013-07-01

    A small three-degree-of-freedom ultrasonic motor has been developed using a simple piezoelectric lead zirconate titanate (PZT)-tube stator (OD 5 mm, ID 3 mm, length 15 mm). The stator drives a ball-rotor into rotational motion around one of three orthogonal (x-, y-, and z-) axes by combing the first longitudinal and second bending vibration modes. A motor prototype was fabricated and characterized; its performance was superior to those of previous motors made with a PZT ceramic/metal composite stator of comparable size. The method for further improving the performance was discussed. The motor can be further miniaturized and it has potential to be applied to medical microrobots, endoscopes or micro laparoscopic devices, and cell manipulation devices. PMID:25004511

  11. Feasibility study of shape control with zero applied voltage utilizing hysteresis in strain-electric field relationship of piezoelectric ceramics

    NASA Astrophysics Data System (ADS)

    Ikeda, T.; Takahashi, T.

    2013-04-01

    To keep a shape of a smart structure controlled by piezoelectric actuators attached to it, electric voltage must be also continued to be applied. To reduce amount of electricity usage, a new control method is proposed. In this method strains of the piezoelectric actuators generated by pulses of voltages are kept with zero/less applied voltage by utilizing the hysteresis in strain versus electric field relationship effectively. In this paper to examine feasibility of this control method residual strains of piezoelectric ceramic plates are measured for combinations of amplitude and period of the applied pulse of voltages. Moreover, a cantilever beam on which a piezoelectric ceramic plate is bonded is made as a simple example of applications to the smart structures, and its deformation behavior after a pulse of voltage is observed. The result shows that the present control method is useful from viewpoint of applied energy, although the strain generated by the piezoelectric actuator is less than the conventional control method where the electric voltage is continued to be applied.

  12. Analysis of axially polarized piezoelectric ceramic cylindrical shells of finite length with internal losses

    NASA Astrophysics Data System (ADS)

    Ebenezer, D. D.; Abraham, Pushpa

    2002-11-01

    A thin shell analytical model of axially polarized piezoelectric ceramic cylinders with internal losses is presented. The Flugge assumptions for strain-displacement relations, Hamilton's principle extended to piezoelectric shells, and the assumption that electric potential has a quadratic variation between the curved surfaces, are used to derive displacement-potential relations that are similar to equations of motion of elastic shells. A solution, with 12 coefficients, to these relations is then derived. The coefficients are complex when the shell has internal losses and are determined by using three mechanical and three electrical boundary conditions at each end--on the flat surfaces. Computed values of input electrical admittance are presented for shells with and without internal losses, and for thin shells as well as shells with wall thickness comparable to the length. They are also compared with results obtained using the finite element program--ATILA. It is shown that the analytical values of resonance frequencies, the maximum value of input electrical conductance, and the maximum and minimum values of input electrical susceptance of thin shells are in excellent agreement with finite element results. The dependence of the maxima and minima in the complex input electrical admittance on the dimensions of the shell is inferred from the numerical results. copyright 2002 Acoustical Society of America.

  13. Fabrication of piezoelectric ceramic fibers by extrusion of PZT powder and PZT sol mixture

    NASA Astrophysics Data System (ADS)

    Kobayashi, Yoshimasa; Um, Tae Y.; Qiu, Jinhao; Tani, Junji; Takahashi, Hirofumi

    2001-07-01

    This study aims to fabricate Pb(Zr,Ti)O3 (PZT) piezoelectric ceramic fibers by extrusion with mixture of PZT powder and PZT sol. The added PZT sol in this study played a role as a binder; the sol changed into PZT crystalline during sintering, and removal process of additives before sintering was not required. To obtain PZT fibers, the condition of sol viscosity adjustment, the mixture ratio of powder and sol for fiber extrusion, and the sintering condition for obtaining polycrystalline fibers were investigated. PZT precursor solution was synthesized from lead acetate trihydrate, zirconium n-propoxide and titanium isopropoxide by reflux at 120 degree(s)C for 3 hours with 2-methoxyethanol. The appropriate adjustment of spinnable sol was achieved by the addition of acetic acid for suppressing the hydrolysis reaction and the curing sol at 80 degree(s)C for promoting the condensation of sol. Green fibers with diameter of about 300micrometers were successfully extruded from the mixture of PZT powder and sol. The extruded fibers sintered at 1200 degree(s)C had the microstructure with 2-6micrometers grains and had no pores or cracks. From the result of displacement behavior measurement, PZT fibers fabricated by firing at 1200 degree(s)C in this study were considered to have desired piezoelectric properties.

  14. The Effects of Piezoelectric Ceramic Dissipation Factor on the Performance of Ultrasonic Transducers

    NASA Astrophysics Data System (ADS)

    DeAngelis, D. A.; Schulze, G. W.

    The dissipation factor (DF) is an important material property of piezoceramics that governs the amount of self-heating under resonant conditions; it essentially quantifies a particular material type for either an actuator or resonator application: high DF materials with typically higher output (d33) are better for actuators, whereas low DF materials with typically lower d33 are better for resonators. Transducer designers must often compromise between mechanical output and DF in the selection of piezoceramics for power ultrasonic applications, and abnormally high DF is one of the main causes of production stoppages. In theory DF is simply the current/voltage phase deviation from an ideal capacitor at 90° (a.k.a. tan(δ) or dielectric loss). Abnormally high DF is typically caused by moisture absorption due to poor ceramic porosity, which causes voltage leakage effects; e.g., seen in transducer production when setting piezo stack preload. Corresponding large increases in capacitance can also be associated with poor porosity, which is counterintuitive unless there is moisture absorption or electrode wicking. This research investigates the mechanisms for abnormally high DF in peizoceramics, and its corresponding effect on transducer performance. It investigates if DF is only affected by the bulk dielectric properties of the piezoceramics (e.g. porosity), or is also influenced by non-uniform electric field effects from electrode wicking. It explores if higher DF ceramics can affect transducer displacement/current gain stability via moisture expulsion at higher drive levels. The investigation focuses solely on the common PZT8 piezoelectric material used with welding transducers for semiconductor wire bonding. Transducers are built with both normal DF peizoceramics, and those with abnormally high DF ceramics which caused production stoppages. Several metrics are investigated such as impedance, displacement gain and capacitance. The experimental and theoretical research methods include Bode plots, SEM cross-sections, Archimedes method, equivalent circuits, laser vibrometry and finite element analysis.

  15. Dielectric, ferroelectric and piezoelectric properties of Nb{sup 5+} doped BCZT ceramics

    SciTech Connect

    Parjansri, Piewpan; Intatha, Uraiwan; Eitssayeam, Sukum

    2015-05-15

    Highlights: • Average grain size of BCZT ceramic decreased with the increasing Nb{sup 5+} doping. • Dielectric constant value is enhanced with Nb{sup 5+} doping. • Dielectric loss of BCZT − x Nb{sup 5+} ceramics was less than 0.03 at room temperature (1 kHz). • Piezoelectric coefficient decreased with the increasing Nb{sup 5+} doping. • The relaxation behavior is enhanced with the doping of Nb{sup 5+}. - Abstract: This work investigated the electrical properties of Nb{sup 5+} (0.0–1.0 mol%) doped with Ba{sub 0.90}Ca{sub 0.10}Zr{sub 0.10}Ti{sub 0.90}O{sub 3} while adding 1 mol% of Ba{sub 0.90}Ca{sub 0.10}Zr{sub 0.10}Ti{sub 0.90}O{sub 3} seeds. The mixed powder was ball milled for 24 h, calcined and sintered at 1200 °C for 2 h and 1450 °C for 4 h, respectively. The XRD patterns of the ceramic samples were investigated by X-ray diffraction. The electrical properties of ceramics were measured and the results indicated that all samples show a pure perovskite phase with no secondary phase. Density and average grain size values were in the range of 5.60–5.71 g/cm{sup 3} and 12.62–1.86 μm, respectively. The highest dielectric constant, ϵ{sub r} at room temperature (1 kHz) was 4636 found at 1.0 mol% Nb. The dielectric loss, tan δ was less than 0.03 for all samples at room temperature (1 kHz). Other electrical properties, P{sub r}, d{sub 33} and k{sub p} values were decreased with Nb doped relates to the decreasing grain size in BCZT ceramics. Moreover, the degrees of phase transition diffuseness and relaxation behavior were observed in the higher Nb doping.

  16. Optimization of poling parameters of mechanically processed PLZT 8/60/40 ceramics based on dielectric and piezoelectric studies

    NASA Astrophysics Data System (ADS)

    Kumar, Ajeet; Bhanu Prasad, V. V.; James Raju, K. C.; James, A. R.

    2015-11-01

    Ultra high strain (Pb0.92La0.08)(Zr0.60Ti0.40)O3 (PLZT 8/60/40) piezoelectric ceramics were synthesized by high energy ball milling method to study the relation between poling conditions (poling electric fields, times and temperatures) and electrical properties. The ceramics were structurally investigated and with the help of ferroelectric P- E hysteresis loop, coercive field was determined. This study deals with the identification of optimum poling conditions and their effect on the piezoelectric and dielectric properties mechanically synthesized PLZT 8/60/40 ceramics. Different combinations of poling parameters were used to measure the values of dielectric constant, dielectric loss, piezoelectric charge ( d 33) and electromechanical coupling coefficients ( k p). These values show that a ferroelectric material can be poled at 5 kV/cm (<0.5 E c ), contrary to common practice of poling far above the coercive field. The effect of aging on the electrical properties was also studied for ceramics poled at 0.6 E c and 3 E c . With the help of this study, poling electric field as well as another two important poling parameters, viz poling temperature and poling time, were optimized. Optimum poling temperature was found to be in the range of 75 C to 125 C with optimal poling time of 30 min. Additionally the effect of ceramic sample thickness on the said properties was also studied. The maximum d 33 and k p values for PLZT ceramics was found to be 715 pC/N and 77%, respectively.

  17. Phase transitions and the piezoelectricity around morphotropic phase boundary in Ba(Zr{sub 0.2}Ti{sub 0.8})O{sub 3}-x(Ba{sub 0.7}Ca{sub 0.3})TiO{sub 3} lead-free solid solution

    SciTech Connect

    Zhang, Le; Zhang, Ming; Wang, Liang; Zhou, Chao; Zhang, Zhen; Yao, Yonggang; Zhang, Lixue; Xue, Dezhen E-mail: xlou03@mail.xjtu.edu.cn Lou, Xiaojie E-mail: xlou03@mail.xjtu.edu.cn; Ren, Xiaobing E-mail: xlou03@mail.xjtu.edu.cn

    2014-10-20

    In this paper, two displacive phase transitions around the morphotropic phase boundary (MPB) in Ba(Zr{sub 0.2}Ti{sub 0.8})O{sub 3}-x(Ba{sub 0.7}Ca{sub 0.3})TiO{sub 3} (BZT-xBCT) ceramics were detected by inspecting two anomalies of the Raman Ti{sup 4+}-O{sup 2−} longitudinal optical mode (∼725 cm{sup −1}). Further, permittivity and X-ray diffraction results demonstrated these two phase transitions originate from tetragonal (T) to rhombohedral (R) through an intermediate orthorhombic (O) phase. Importantly, we found that the maximum piezoelectric response (d{sub 33} = 545pC/N) was achieved at the boundary between the T and O phase, indicating that the giant piezoelectricity of BZT-xBCT may mainly stem from the T-O phase boundary due to easier polarization rotation and larger lattice softening.

  18. Structure and ferroelectric studies of (Ba{sub 0.85}Ca{sub 0.15})(Ti{sub 0.9}Zr{sub 0.1})O{sub 3} piezoelectric ceramics

    SciTech Connect

    Venkata Ramana, E.; Mahajan, A.; Graça, M.P.F.; Mendiratta, S.K.; Monteiro, J.M.; Valente, M.A.

    2013-10-15

    Graphical abstract: - Highlights: • (Ba{sub 0.85}Ca{sub 0.15})(Ti{sub 0.9}Zr{sub 0.1})O{sub 3} (BCTZO) ceramic was synthesized by the ceramic method. • In situ XRD and Raman spectra showed the phase transition of BCTZO around 360 K. • The ceramics showed a tunability of 82% at 40 kV cm{sup −1} electric field. • BCTZO exhibited good quality factor of 111 at microwave frequencies. • Piezoforce microscopy studies indicated the switchability of ferroelectric domains. - Abstract: We have synthesized and studied the structural and ferroelectric properties of lead-free 0.5(Ba{sub 0.7}Ca{sub 0.3})TiO{sub 3}–0.5Ba(Zr{sub 0.2}Ti{sub 0.8})O{sub 3} ceramics in the temperature region of its ferroelectric transition. The synthesized material showed high dielectric constant, low loss and good pyroelectric figure of merit. From the temperature dependent X-ray diffraction measurements, we determined the tricritical point to be in the temperature range of 303–400 K. The dielectric measurements indicate a diffuse ferroelectric phase transition (DPT) around 360 K in agreement with the X-ray measurements. We studied the evolution of Raman spectra with temperature to understand the nature of phase transition in BaTiO{sub 3} (BTO) and the BCTZO. The results indicates that the transition of ferroelectric–paraelectric state is not sharp as in the case of BTO and the polar state persists through the paraelectric state. In general, our study indicates that there are ferroelectric domains of nanometer size beyond the commonly defined transition temperature. The observation of local piezoelectric hysteresis loop indicated the existence of intrinsic ferroelectric property of the ceramic at the nanoscale. The ceramics exhibited electric field tunable dielectric properties with a tunability of 82% at an applied DC field of 40 kV cm{sup −1}, low dielectric loss of 0.001 and room temperature pyroelectric coefficient of 6 × 10{sup −8} C cm{sup −2} K{sup −1} and the detectivity of 1.9 × 10{sup −8} C cm{sup −1} J{sup −1}; larger than those reported for other BaTiO{sub 3}-based materials. Overall, our results indicate that BCTZO ceramics with coexistence of rhombohedral–tetragonal phases is a promising candidate for lead-free ferroelectric applications.

  19. A piezoelectric active mirror suspension system embedded into low-temperature cofired ceramic.

    PubMed

    Sobocinski, Maciej; Leinonen, Mikko; Juuti, Jari; Jantunen, Heli

    2012-09-01

    Low-temperature cofired ceramic (LTCC) has proven to be a cost-effective, flexible technology for producing complicated structures such as sensors, actuators, and microsystems. This paper presents a piezoelectric active mirror suspension system embedded into LTCC. In the structure, the LTCC was used as a package, for the passive layers of piezoelectric monomorphs, as support for the mirrors, and as a substrate for the conductors. The active mirror structure, 17 mm in diameter, was made by compiling 20 LTCC layers using common LTCC processing techniques. Each sample contained a laser-micromachined bulk lead zirconate titanate (PZT) structure which formed a monomorph with the LTCC during the firing process. A mirror substrate (diameter 4 mm) was mounted in the middle of the monomorph arms for evaluation of the positioning performance, where each of the three arms had independent signal electrodes and a common ground electrode. Electrical and electromechanical properties were investigated with an LCR meter, network analyzer, and laser vibrometer for the different arms and the mirror. The active mirror structure exhibited more than 1 μm dc displacement for mirror leveling and also allowed small changes in mirror angle up to 0.06°. The first bending resonance frequency of the structure with the mirror was detected at 11.31 kHz with 4.0 μm displacement; 13.02 kHz and 2.7 μm were obtained without the mirror. The structure exhibited characteristics feasible for further utilization in tunable Fabry-Perot filter applications, allowing the mounting of active mirrors on both sides with distance and angle control. PMID:23007772

  20. NASA DOD Lead Free Electronics Project

    NASA Technical Reports Server (NTRS)

    Kessel, Kurt R.

    2008-01-01

    The primary'technical objective of this project is to undertake comprehensive testing to generate information on failure modes/criteria to better understand the reliability of: Packages (e.g., Thin Small Outline Package [TSOP], Ball Grid Array [BGA], Plastic Dual In-line Package [PDIPD assembled and reworked with lead-free alloys Packages (e.g., TSOP, BGA, PDIP) assembled and reworked with mixed (lead/lead-free) alloys.

  1. Ferroelectric, piezoelectric, and dielectric properties of BiScO3-PbTiO3-Pb(Cd1/3Nb2/3)O3 ternary high temperature piezoelectric ceramics

    NASA Astrophysics Data System (ADS)

    Zhao, Tian-Long; Chen, Jianguo; Wang, Chun-Ming; Yu, Yang; Dong, Shuxiang

    2013-07-01

    (0.95-x)BiScO3-xPbTiO3-0.05Pb(Cd1/3Nb2/3)O3 (BS-xPT-PCN) high temperature piezoelectric ceramics near the morphotropic phase boundary (MPB) have been synthesized by traditional solid-state reaction methods. The microstructural morphology, phase structure, and electrical properties of BS-xPT-PCN ceramics were investigated in detail. X-ray diffraction analysis indicated BS-xPT-PCN ceramics have a pure perovskite structure. The coexistence of rhombohedral and tetragonal phases at MPB composition enhanced the polarizability by the coupling between two dynamically equivalent energy states, resulting in the improved piezoelectric and ferroelectric properties at MPB vicinity. The BS-xPT-PCN (x = 0.60) ceramics possess the optimal piezoelectric and ferroelectric properties with d33 = 505pC/N, kp = 55.9%, kt = 36.5%, strain = 0.23% (under the electric field 37.5 kV/cm), and Pr = 39.7 μC/cm2. High temperature dielectric behaviors showed diffuse phase transition in BS-xPT-PCN ceramics. The Curie temperature Tc was found to increase from 371 °C to 414 °C with x increasing from 0.58 to 0.62. All these results together with the good thermal stabilities make the BS-xPT-PCN ceramics promising candidates for high temperature piezoelectric applications.

  2. Dielectric and piezoelectric properties of the KNN ceramic compound doped with Li, La and Ta

    NASA Astrophysics Data System (ADS)

    Fuentes, J.; Portelles, J.; Durruthy-Rodríguez, M. D.; H'Mok, H.; Raymond, O.; Heiras, J.; Cruz, M. P.; Siqueiros, J. M.

    2015-02-01

    With the purpose of improving the dielectric and piezoelectric properties of (K0.5Na0.5)NbO3 (KNN), a multiple doping strategy was tested in this research. Piezoceramics with composition [(K0.5Na0.5)0.94Li0.06]0.97La0.01(Nb0.9Ta0.1)O3 were prepared by the traditional ceramic method. The calcined powders were sintered in their own atmosphere at 1,100 °C for 1.0, 1.5 and 2.5 h. X-ray diffraction analysis showed that the Li+, La3+ and Ta5+ cations diffuse into the KNN structure to form a perovskite-structured solid solution. For 1 h sintering time, a dominant orthorhombic phase is obtained, whereas for the longer times, the dominant phase was tetragonal. The presence of a tetragonal tungsten-bronze minority second phase is confirmed. Scanning electron micrographs show rectangular-shaped grains with a mean size of 1.1 ± 0.2 μm. The existence of pores and traces of a liquid phase favoring grain growth and homogeneity is also observed. Experimental results show an enhancement of the permittivity associated with the enlargement of the c parameter of the cell that increases with sintering time. Li+ incorporation into the structure is made evident by its transition temperature at 400 °C different from those of KNNLaTi (81-110 °C) and KNNLaTa (340 °C). An analysis of the phase transition of the samples indicates a normal rather than a diffuse transition. The electromechanical parameters k p, Q m, σ p, s 11, d 31 and g 31 are determined and compared to those of commercial PZT ceramics.

  3. Dielectric and piezoelectric properties of the KNN ceramic compound doped with Li, La and Ta

    NASA Astrophysics Data System (ADS)

    Fuentes, J.; Portelles, J.; Durruthy-Rodríguez, M. D.; H'Mok, H.; Raymond, O.; Heiras, J.; Cruz, M. P.; Siqueiros, J. M.

    2014-09-01

    With the purpose of improving the dielectric and piezoelectric properties of (K0.5Na0.5)NbO3 (KNN), a multiple doping strategy was tested in this research. Piezoceramics with composition [(K0.5Na0.5)0.94Li0.06]0.97La0.01(Nb0.9Ta0.1)O3 were prepared by the traditional ceramic method. The calcined powders were sintered in their own atmosphere at 1,100 °C for 1.0, 1.5 and 2.5 h. X-ray diffraction analysis showed that the Li+, La3+ and Ta5+ cations diffuse into the KNN structure to form a perovskite-structured solid solution. For 1 h sintering time, a dominant orthorhombic phase is obtained, whereas for the longer times, the dominant phase was tetragonal. The presence of a tetragonal tungsten-bronze minority second phase is confirmed. Scanning electron micrographs show rectangular-shaped grains with a mean size of 1.1 ± 0.2 μm. The existence of pores and traces of a liquid phase favoring grain growth and homogeneity is also observed. Experimental results show an enhancement of the permittivity associated with the enlargement of the c parameter of the cell that increases with sintering time. Li+ incorporation into the structure is made evident by its transition temperature at 400 °C different from those of KNNLaTi (81-110 °C) and KNNLaTa (340 °C). An analysis of the phase transition of the samples indicates a normal rather than a diffuse transition. The electromechanical parameters k p, Q m, σ p, s 11, d 31 and g 31 are determined and compared to those of commercial PZT ceramics.

  4. Bright upconversion luminescence and increased Tc in CaBi2Ta2O9:Er high temperature piezoelectric ceramics

    NASA Astrophysics Data System (ADS)

    Peng, Dengfeng; Wang, Xusheng; Xu, Chaonan; Yao, Xi; Lin, Jian; Sun, Tiantuo

    2012-05-01

    Er3+ doped CaBi2Ta2O9 (CBT) bismuth layered-structure high temperature piezoelectric ceramics were synthesized by the traditional solid state method. The upconversion (UC) emission properties of Er3+ doped CBT ceramics were investigated as a function of Er3+ concentration and incident pump power. A bright green upconverted emission was obtained under excitation 980 nm at room temperature. The observed strong green and weak red emission bands corresponded to the transitions from 4S3/2 and 4F9/2 to 4I15/2, respectively. The dependence of UC emission intensity on pumping power indicated that a three-photon process was involved in UC emissions. Studies of dielectric with temperature have also been carried out. Introduction of Er increased the Curie temperature of CBT, thus, making this ceramic suitable for sensor applications at higher temperatures. Because of its strong up-converted emission and increased Tc, the multifunctional high temperature piezoelectric ceramic may be useful in high temperature sensor, fluorescence thermometry, and optical-electro integration applications.

  5. Dielectric properties and glassy behavior study of 70(Na0.5Bi0.5) TiO3-30SrTiO3 lead-free ceramic

    NASA Astrophysics Data System (ADS)

    Praharaj, S.; Rout, D.; Kar, B. B.; Subramanian, V.

    2016-05-01

    This paper reports the dielectric and glassy behavior of 70(Na0.5Bi0.5) TiO3-30SrTiO3 (NBT-30ST) lead-free perovskite relaxor. The temperature dependent dielectric data indicates that the material undergoes a diffuse phase transition at Tm (temperature corresponding to maximum dielectric constant) with diffuseness coefficient γ˜2. The material also shows frequency dispersion around Tm with a high ΔTm (Tm,1MHz - Tm, 0.1kHz) value of ˜42. The above parameters manifest strong relaxor behavior of NBT-30ST. Moreover, the results are analyzed by employing empirical models such as V-F law, Power law to explore the glassy behavior associated with the system. The frequency dependent Tm analysis revealed greater interactions between the polar nano regions (PNRs). For further information on PNRs, the dielectric behavior at much higher and lower temperature than Tm has also been analyzed.

  6. Phase structure and electrical properties of PSN-PMN-PZ-PT quaternary piezoelectric ceramics near the morphotropic phase boundary

    NASA Astrophysics Data System (ADS)

    Chen, Haiyan; Fan, Chunhua

    2010-04-01

    0.06Pb(Sb 1/2Nb 1/2)O 3-0.06Pb(Mn 1/3Nb 2/3)O 3-0.88Pb(Zr xTi 1-x)O 3 (PSN-PMN-PZ-PT) quaternary piezoelectric ceramics with varying Zr/Ti ratios located near the morphotropic phase boundary (MPB) were prepared by powder solid-state reaction. The phase structure, dielectric and piezoelectric properties and temperature stability of the systems were investigated. In the present system the MPB, in which the tetragonal and rhombohedral phases coexist, is in a composition range of 0.49< x<0.52. The relative permittivity, dielectric dissipation, piezoelectric coefficient and electromechanical coupling factor reach maximum values, while the mechanical quality factor is lowest when x=0.50. These properties include ε33T/ ε0=1730, tan δ=0.007, d33=365 pC/N, d31=-151 pC/N, k p=0.62, k31=0.37 and Qm=1170. A Curie temperature of 308 °C was achieved when x=0.50. The resonant frequency changes from a positive to a negative value as the Zr/Ti ratio increases. The smallest temperature coefficient (Δ fr/Δ Tfr25 °C =3.08×10 -5/°C) was obtained between -50 and 120 °C in the sample when x=0.50. In the temperature range of 20-80 °C, the piezoelectric coefficient and electromechanical coupling factor show high temperature stability and the mechanical quality factor maintained a comparatively high value close to room temperature when x=0.50. The properties of this type of ceramics make it a very promising piezoelectric material for application in ultrasonic motors.

  7. Self-sensing tunable vibration absorber incorporating piezoelectric ceramic-magnetostrictive composite sensoriactuator

    NASA Astrophysics Data System (ADS)

    Duan, Yuan-Feng; Wing Or, Siu

    2011-08-01

    A novel self-sensing tunable vibration absorber (SSTVA) is developed for active absorption of vibrations in vibrating structures. The SSTVA consists of a piezoelectric ceramic-magnetostrictive composite sensoriactuator suspended in a mounting frame by two flexible beams connected to the axial ends of the sensoriactuator. The sensoriactuator serves to produce an axial force for tuning of the natural frequency of the SSTVA, to gather the signals associated with structural vibrations and to provide a lumped damped mass for the SSTVA. By monitoring the sensoriactuator output voltage while adjusting its input magnetic field (or electric current), the natural frequency of the SSTVA is tuned to the targeted resonance frequency of a structure. In this paper, the working principle, design prototype and operating performance of a 62.5 Hz SSTVA are reported. A high tunability of the natural frequency of 20% and a good sensing capability of vibrations comparable to a commercial accelerometer are obtained, together with a high absorbability of vibrations of ~ 4 dB in a steel-plate-neoprene resilient mount structure.

  8. Design of a self-adaptive fuzzy PID controller for piezoelectric ceramics micro-displacement system

    NASA Astrophysics Data System (ADS)

    Zhang, Shuang; Zhong, Yuning; Xu, Zhongbao

    2008-12-01

    In order to improve control precision of the piezoelectric ceramics (PZT) micro-displacement system, a self-adaptive fuzzy Proportional Integration Differential (PID) controller is designed based on the traditional digital PID controller combining with fuzzy control. The arithmetic gives a fuzzy control rule table with the fuzzy control rule and fuzzy reasoning, through this table, the PID parameters can be adjusted online in real time control. Furthermore, the automatic selective control is achieved according to the change of the error. The controller combines the good dynamic capability of the fuzzy control and the high stable precision of the PID control, adopts the method of using fuzzy control and PID control in different segments of time. In the initial and middle stage of the transition process of system, that is, when the error is larger than the value, fuzzy control is used to adjust control variable. It makes full use of the fast response of the fuzzy control. And when the error is smaller than the value, the system is about to be in the steady state, PID control is adopted to eliminate static error. The problems of PZT existing in the field of precise positioning are overcome. The results of the experiments prove that the project is correct and practicable.

  9. Adaptive hybrid control for linear piezoelectric ceramic motor drive using diagonal recurrent CMAC network.

    PubMed

    Wai, Rong-Jong; Lin, Chih-Min; Peng, Ya-Fu

    2004-11-01

    This paper presents an adaptive hybrid control system using a diagonal recurrent cerebellar-model-articulation-computer (DRCMAC) network to control a linear piezoelectric ceramic motor (LPCM) driven by a two-inductance two-capacitance (LLCC) resonant inverter. Since the dynamic characteristics and motor parameters of the LPCM are highly nonlinear and time varying, an adaptive hybrid control system is therefore designed based on a hypothetical dynamic model to achieve high-precision position control. The architecture of DRCMAC network is a modified model of a cerebellar-model-articulation-computer (CMAC) network to attain a small number of receptive-fields. The novel idea of this study is that it employs the concept of diagonal recurrent neural network (DRNN) in order to capture the system dynamics and convert the static CMAC into a dynamic one. This adaptive hybrid control system is composed of two parts. One is a DRCMAC network controller that is used to mimic a conventional computed torque control law due to unknown system dynamics, and the other is a compensated controller with bound estimation algorithm that is utilized to recover the residual approximation error for guaranteeing the stable characteristic. The effectiveness of the proposed driving circuit and control system is verified with hardware experiments under the occurrence of uncertainties. In addition, the advantages of the proposed control scheme are indicated in comparison with a traditional integral-proportional (IP) position control system. PMID:15565776

  10. Effects of BiAlO{sub 3}-doping on dielectric and ferroelectric properties of 0.93Na{sub 0.5}Bi{sub 0.5}TiO{sub 3}–0.07BaTiO{sub 3} lead-free ceramics

    SciTech Connect

    Wang, Jian; Chen, Xiao-ming Zhao, Xu-mei; Liang, Xiao-xia; Zhou, Jian-ping; Liu, Peng

    2015-07-15

    Highlights: • BiAlO{sub 3}-doped BNT-based ceramics were synthesized via a conventional solid state reaction method. • T% values are 56%, 32%, 37%, and 37% for the ceramics with x = 0, 0.01, 0.02 and 0.06, respectively. • The mean grain sizes of the ceramics with x = 0, 0.01, 0.02 and 0.06 are about 1.1, 0.9, 0.8 and 0.7 μm, respectively. • Dielectric anomalies in the ϵ{sub r}–T curves are close related to the BiAlO{sub 3} amounts. • The ceramic with x = 0.01 shows the P{sub m} of 32.5 μC/cm{sup 2}, P{sub r} of 24.1 μC/cm{sup 2}, E{sub c} of 20.0 kV/cm and d{sub 33} of 166 pC/N. - Abstract: (1 − x)(0.93Na{sub 0.5}Bi{sub 0.5}TiO{sub 3}–0.07BaTiO{sub 3})–xBiAlO{sub 3} (BNBT-xBA, x = 0, 0.01, 0.02, 0.06) lead-free ceramics were synthesized via a conventional solid state reaction method. Crystallite structure, microstructure, dielectric and ferroelectric properties of the BNBT–xBA ceramics were studied in detail. X-ray diffraction results show that all ceramics exhibit typical diffraction peaks of ABO{sub 3} perovskite structure. Scanning electron microscope images show that all samples have fine microstructures. Both Curie temperature and maximum dielectric constant vary with the change in the BiAlO{sub 3} amounts. The values of hysteresis loop squareness were calculated to be 1.26, 0.81, 0.51 and 0.36 for the ceramics with x = 0, 0.01, 0.02 and 0.06, respectively, indicating a decreased switching behavior of polarization. The changes in dielectric and ferroelectric properties of the ceramics are also discussed.

  11. Enhanced piezoelectric properties of lead zirconate titanate (PZT) sol-gel derived ceramics using single crystal PZT cubes

    NASA Astrophysics Data System (ADS)

    Lin, Yirong; Andrews, Clark; Sodano, Henry A.

    2010-04-01

    Piezoceramic materials have attracted much attention for sensing, actuation, structural health monitoring and energy harvesting applications in the past two decades due to their excellent coupling between energy in the mechanical and electrical domains. Among all piezoceramic materials, lead zirconate titanate (PZT) has been the most broadly studied and implemented, in industrial applications due to its high piezoelectric coupling coefficients. Piezoceramic materials are most often employed as thin films or monolithic wafers. While there are numerous methods for the synthesis of PZT films, the sol-gel processing technique is the most widely used due to its low densification temperature, the ease at which the film can be applied without costly physical deposition equipment and the capability to fabricate both thin and thick films. However, the piezoelectric properties of PZT sol-gel derived films are substantially lower than those of bulk materials, which limit the application of sol-gel films. In comparison, single crystal PZT materials have higher piezoelectric coupling coefficients than polycrystalline materials due to their uniform dipole alignment. This paper will introduce a novel technique to enhance the piezoelectric properties of PZT sol-gel derived ceramics through the use of single crystal PbZr0.52Ti0.48O3 microcubes as an inclusion in the PZT sol-gel. The PZT single crystal cubes are synthesized through a hydrothermal based method and their geometry and crystal structure is characterized through scanning electron microscopy (SEM) and X-ray diffraction (XRD). A mixture of PZT cubes and sol-gel will then be sintered to crystallize the sol-gel and obtain full density of the ceramic. XRD and SEM analysis of the cross section of the final ceramics will be performed and compared to show the crystal structure and microstructure of the samples. The P-E properties of the samples will be tested using a Sawyer-Tower circuit. Finally, a laser interferometer will be used to directly measure the piezoelectric strain-coupling coefficient of the PZT sol-gel ceramics with and without PZT cube inclusions. The results will show that with the integration of PZ0.52T0.48 crystal inclusions the d33 coupling coefficient will increase more than 200% compared to that of pure PbZr0.52Ti0.48O3 sol-gel.

  12. Influence of zirconium substitution on dielectric, ferroelectric and field-induced strain behaviors of lead-free 0.99[Bi1/2(Na0.82K0.18)1/2(Ti1- x Zr x )O3]-0.01LiSbO3 ceramics

    NASA Astrophysics Data System (ADS)

    Zaman, A.; Iqbal, Y.; Hussain, A.; Ryu, G. H.; Song, T. K.; Kim, M. H.; Kim, W. J.

    2012-09-01

    The Crystal structure, dielectric, ferroelectric and field-induced strain behaviors of lead-free 0.99[Bi1/2(Na0.82K0.18)1/2(Ti1- x Zr x )O3]-0.01LiSbO3 (BNKTZ-LS) ceramics were investigated in the composition range x = 0 - 0.040. XRD patterns revealed the formation of a pure perovskite phase with no apparent structural phase transition. The temperature-dependent dielectric peaks of the BNKTZ-LS ceramics broadened and the ferroelectric polarizations decreased with increasing Zr concentration. Ferroelectric and bipolar field induced-strain curves indicated a disruption of ferroelectric order upon Zr addition into the BNKT-LS ceramics. This destabilization of the ferroelectric order was accompanied by an enhanced field-induced strain. A high field-induced strain ( S = 0.30%) with a normalized strain ( d*33 = S max / E max = 500 pm/V) was observed at an applied electric field of 6 kV/mm at x = 0.020.

  13. Elastic, piezoelectric, and dielectric characterization of modified BiScO3-PbTiO3 ceramics.

    PubMed

    Zhang, Shujun; Alberta, Edward F; Eitel, Richard E; Randall, Clive A; Shrout, Thomas R

    2005-11-01

    The perovskite solid solution system (1-x)BiScO3-(x)PbTiO3 represents an interesting new family of high-temperature piezoelectric materials. Compositions near the morphotropic phase boundary (x approximately 0.64) have been reported to have high Curie temperatures (Tc > 450 degrees C) and good piezoelectric coefficients (d33 approximately 460 pC/N). In this work, manganese additions were used to improve the high-temperature electrical resistivity and RC time constant of compositions near the morphotropic phase boundary. The addition of manganese was found to shift Tc to slightly lower temperatures (442 degrees C and 456 degrees C for x = 0.64 and x = 0.66, respectively). The piezoelectric activities of the modified materials were found to be reduced slightly due to the hardening effect of manganese; however, the temperature stability and resistivity of the modified materials were significantly enhanced. In this paper we present, for the first time, a complete set of materials constants, including the elastic (sij, cij), piezoelectric (dij, eij, gij, hij), dielectric (epsilonij, betaij), and electromechanical (kij) coefficients and compare them to both unmodified 0.36BiScO3-0.64PbTiO3 and PZT5A ceramics. PMID:16422427

  14. Structural, ferroelectric and magnetic study of lead free (Na{sub 0.5}Bi{sub 0.5}){sub 1-x}La{sub x}Ti{sub 0.988}Fe{sub 0.012}O{sub 3} (x=0,0.01,0.03,0.05) ceramic

    SciTech Connect

    Parmar, Kusum Sharma, Anshu; Sharma, Hakikat; Negi, N. S.

    2015-05-15

    Lead free (Na{sub 0.5}Bi{sub 0.5}){sub 1-x}La{sub x}Ti{sub 0.988}Fe{sub 0.012}O{sub 3} ceramic having compositions (x=0, 0.01, 0.03, 0.05) has been prepared by sol gel method using citric acid. Structural analysis has been done by X-ray diffraction and FTIR measurements. XRD patterns have been confirmed perovskite structure for all samples. FTIR absorption band at around ∼630 cm{sup −1} is observed for all samples which confirm perovskite phase formation in samples. With increasing La concentration, shifting in XRD peaks and FTIR absorption bands is observed which suggests incorporation of La on A-site in prepared (Na{sub 0.5}Bi{sub 0.5}){sub 1-x}La{sub x}Ti{sub 0.988}Fe{sub 0.012}O{sub 3} samples. Effect of La substitution on Ferroelectric (Polarization vs. Electric field) and Magnetic (Magnetization vs. Magnetic field) properties have been studied at room temperature. All samples exhibit weak ferromagnetic order and also possess ferroelectric behavior which provides new insight to lead free single phase multiferroic materials.

  15. Processing and properties of bismuth sodium titanate-based piezoelectric ceramics for transducer applications

    NASA Astrophysics Data System (ADS)

    Herabut, Aree

    1997-11-01

    Piezoelectric ceramics have been key materials for transducer applications. Most practical materials are developed from the binary and ternary systems of lead-based perovskite piezoceramics. The main drawbacks of these lead-based materials include processing of PbO and, also, PbO evaporation during sintering, leading to a serious pollution problem. The toxicity and volatility of lead oxide are critical environmental issues which cannot be overlooked. Through the concept of Smolenskii, it is possible to replace Pb with elements having similar electron configuration and still obtain a material exhibiting similar behavior in spontaneous polarization. The Bisb{0.5}Nasb{0.5}TiOsb3 (BNT) composition has a perovskite structure and presents ferroelectric behavior with a Curie temperature of 320sp°C. However, the random displacement between the Nasp+ and Bisp{3+} ions at elevated temperature results in the abnormal dielectric permittivity and loss as functions of temperature and frequency. Additionally, the high coercive field of this BNT composition (Esbc = 70 kV/cm) leads to a difficulty in successful poling. In this research, the structure-processing-properties relations of BNT and solid solutions of BNT with Pbsb{0.75}Casb{0.25}TiOsb3 were assessed. Based on the flexibility of the perovskite structure in allowing an incorporation of various cation sizes, isovalent and aliovalent substitutions were utilized in the compositional modification of BNT. These modified BNT compositions were formulated by the conventional mixed oxide method, following optimized powder processing, specimen fabrication, and sintering procedures. Two kinds of distortion from the ideal perovskite structure, the packing and off-center effects, were expected to be involved in this modification. A series of the modified BNT piezoceramics encompassing various dielectric and piezoelectric properties was prepared by the addition of three rare-earth ions, Lasp{3+}, Ndsp{3+}, and Smsp{3+}, and a pentavalent ion, Nbsp{5+}. These modified BNT compositions were calcined in the range of 800-900sp°C for 2-5 hrs and then sintered at 1050-1200sp°C for 1-4 hrs. Conventional poling was performed at 50sp°C with an applied field of 40-70 kV/cm for 5 minutes. A composition of the BNT with 0.5 at% La yielded a K value of 515, ksb{t} of 45%, dsb{33} of 100 pC/N, dsb{h} of 65 pC/N and ksb{t}/ksb{p} of 3.5, which is considerable promising for transducer applications.

  16. Structure evolution and piezoelectric properties across the morphotropic phase boundary of Sm-substituted BiFeO3 ceramics

    NASA Astrophysics Data System (ADS)

    Shi, Xin Xin; Liu, Xiao Qiang; Chen, Xiang Ming

    2016-02-01

    The evolution of structure, ferroelectric, and piezoelectric properties in Bi1-xSmxFe0.99Ti0.01O3 ceramics was extensively investigated within the entire morphotropic phase boundary region with 0 ≤ x ≤ 0.20. A sequential phase transition of R3c-Pna21-Pbnm with increasing Sm content was revealed by Rietveld refinement of the X-ray diffraction data together with the macroscopic ferroelectric measurements. Both ferroelectric and piezoelectric properties showed a great enhancement in the vicinity of the R3c/Pna21 (polar-to-polar) phase boundary, which should be caused by the field-induced phase transition between these two phases. Such field-induced phase transition might be essentially accompanied by a change of magnetic state, which indicated a way of controlling magnetism by means of electric field.

  17. Ferroelastic domains in lead-free barium zirconate titanate - barium calcium titanate piezoceramics

    NASA Astrophysics Data System (ADS)

    Ehmke, Matthias Claudius

    Piezoelectricity was first discovered by Pierre and Jaque Curie in the year 1880. Nowadays, piezoelectric materials are used in many application such as high voltage generation in gas igniters, actuation in micro-positioning devices, generation and detection of acoustic waves, emitters and receivers for sonar technology, ultrasonic cleaning, ultrasound medical therapy, and micropumps for ink-jet printers. The most commonly used piezoelectric material since the 1950's is the solid solution system lead zirconate titanate (PZT) that offers high piezoelectric performance under a large range of operating conditions. However, the toxicity of lead requires the replacement of PZT. The studied lead-free alternatives are commonly based on potassium sodium niobate (KNN) and bismuth sodium titanate (BNT), and more recently zirconium and calcium substituted barium titanate (BZT-BCT). The BZT-BCT system exhibits large piezoelectric coefficients that can exceed even those of most PZT compositions under certain conditions. Piezoelectricity was first discovered by Pierre and Jaque Curie in the year 1880. Nowadays, piezoelectric materials are used in many application such as high voltage generation in gas igniters, actuation in micro-positioning devices, generation and detection of acoustic waves, emitters and receivers for sonar technology, ultrasonic cleaning, ultrasound medical therapy, and micropumps for ink-jet printers. The most commonly used piezoelectric material since the 1950's is the solid solution system lead zirconate titanate (PZT) that offers high piezoelectric performance under a large range of operating conditions. However, the toxicity of lead requires the replacement of PZT. The studied lead-free alternatives are commonly based on potassium sodium niobate (KNN) and bismuth sodium titanate (BNT), and more recently zirconium and calcium substituted barium titanate (BZT-BCT). The BZT-BCT system exhibits large piezoelectric coefficients that can exceed even those of most PZT compositions under certain conditions.

  18. Accelerated Aging of Lead-Free Propellant

    NASA Technical Reports Server (NTRS)

    Furrow, Keith W.; Jervey, David D.

    2000-01-01

    Following higher than expected 2-NDPA depletion rates in a lead-free doublebase formulation (RPD-422), an accelerated aging study was conducted to verify the depletion rates. A test plan was prepared to compare the aging characteristics of lead-free propellant and NOSIH-AA2. The study was also designed to determine which lead-free ballistic modifiers accelerated 2-NDPA depletion. The increased depletion rate occurred in propellants containing monobasic copper salicylate. Four lead-free propellants were then formulated to improved aging characteristics over previous lead-free propellant formulations. The new formulations reduced or replaced the monobasic copper salicylate. The new formulations had improved aging characteristics. Their burn rates, however, were unacceptable for use in a 2.75 inch rocket. To compare aging characteristics, stabilizer depletion rates of RPD-422, AA2, M28, and RLC 470/6A were measured or taken from the literature. The data were fit to a kinetic model. The model contained first and zero order terms which allowed the stabilizer concentration to go to zero. In the model, only the concentration of the primary stabilizer was considered. Derivatives beyond the first nitrated or nitroso derivative of 2-NPDA were not considered. The rate constants were fit to the Arrhenius equation and extrapolated to lower temperatures. The time to complete stabilizer depletion was estimated using the kinetic model. The four propellants were compared and the RPD-422 depleted faster at 45 C than both A22 and M28. These types of predictions depend on the validity of the model and on confidence in the Arrhenius relationship holding at lower temperatures. At 45 C, the zero order portion of the model dominates the depletion rate.

  19. Complete matrix of the piezoelectric, dielectric, and elastic material constants of 1-3 piezoelectric ceramic/polymer composites

    NASA Astrophysics Data System (ADS)

    Sherrit, Stewart; Wiederick, Harvey D.; Mukherjee, Benoy K.

    1997-11-01

    The results of our analysis of a set of lead zirconate titanate (PZT-5H)/hard polyurethane 1 - 3 piezoelectric composites produced by injection molding are presented. Two groups of samples with 15 and 30 volume percent PZT were analyzed using impedance resonance techniques. Results from the thickness, radial, length thickness, thickness shear, and the length extensional modes allow the determination of the effective material constants. The complete effective (sE, d, (epsilon) T) matrix is presented for the two compositions. The limitations of using resonance techniques to determine composite material properties are discussed.

  20. Effects of poling termination and aging process on piezoelectric properties of Mn-doped BaTi0.96Zr0.04O3 ceramics

    NASA Astrophysics Data System (ADS)

    Murakami, Shunsuke; Watanabe, Takayuki; Suzuki, Tatsuya; Matsuda, Takanori; Miura, Kaoru

    2015-10-01

    The effects of poling termination and aging process on the piezoelectric properties at room temperature of 1 mol % Mn-doped Ba(Ti0.96Zr0.04)O3 ceramics with orthorhombic structure have been investigated. It is expected that the substitution of accepter Mn into the Ti0.96Zr0.04 site will result in a defect dipole with an oxygen vacancy and generate an internal field (Ed) in 1 mol % Mn-doped Ba(Ti0.96Zr0.04)O3 ceramics. In order to investigate the effect of the rearrangement of defect dipoles on the piezoelectric properties, the following two investigations have been performed. One is on the relationship between the piezoelectric properties and the change in the poling-termination temperature (TP) around the orthorhombic-tetragonal temperature (TOT). The result shows that piezoelectric properties are related to spontaneous polarizations, and that the rearrangement of defect dipoles is small. The other is on the influence of aging treatment at 70 °C for 24 h on the piezoelectric properties. Above TOT, the piezoelectric properties are almost the same, independent of the TP of the specimen. This result suggests that the change in piezoelectric properties is due to a change in the domain in spontaneous polarizations and that the rearrangement of defect dipoles is also small. The result of domain observation reflection electron microscopy supports the rearrangement of spontaneous polarizations during the aging process.

  1. New potassium-sodium niobate ceramics with a giant d33.

    PubMed

    Wang, Xiaopeng; Wu, Jiagang; Xiao, Dingquan; Cheng, Xiaojing; Zheng, Ting; Lou, Xiaojie; Zhang, Binyu; Zhu, Jianguo

    2014-05-14

    For potassium-sodium niobate, poor piezoelectric properties always perplex most researchers, and then it becomes important to attain a giant piezoelectricity. Here we reported a giant piezoelectric constant in (1-x)(K0.48Na0.52)(Nb0.95Sb0.05)O3-xBi0.5Ag0.5ZrO3 lead-free ceramics. The rhombohedral-tetragonal phase boundary was shown in the ceramics with 0.04ceramic with x=0.0425 possesses a giant d33 of ?490 pC/N. We also discussed the physical mechanisms of enhanced piezoelectricity. As a result, such a research can benefit the sustainable development of (K,Na)NbO3 materials. PMID:24784228

  2. Lead-free ternary perovskite compounds with large electromechanical strains

    NASA Astrophysics Data System (ADS)

    Jarupoom, Parkpoom; Patterson, Eric; Gibbons, Brady; Rujijanagul, Gobwute; Yimnirun, Rattikorn; Cann, David

    2011-10-01

    Lead-free compounds based on perovskite solid solutions in the ternary system (Bi1/2Na1/2)TiO3-(Bi1/2K1/2)TiO3-Bi(X1/2Ti1/2)O3, where X = Ni and Mg have been shown to exhibit large electromechanical strains. While the perovskite end members Bi(Mg1/2Ti1/2)O3 and Bi(Ni1/2Ti1/2)O3 display limited stability in their pure state, both compounds were found to have solid solubilities of at least 50 mol. % with (Bi1/2Na1/2)TiO3 and (Bi1/2K1/2)TiO3. Most importantly, under relatively large applied fields, these materials exhibited large hysteretic electromechanical strains characterized by a parabolic shape. With effective piezoelectric coefficients (d33*) greater than 500 pm/V, these systems have excellent potential as a Pb-free piezoelectric materials.

  3. Enhanced temperature stability in <111> textured tetragonal Pb(Mg1/3Nb2/3)O3-PbTiO3 piezoelectric ceramics

    NASA Astrophysics Data System (ADS)

    Yan, Yongke; Yang, Lijuan; Zhou, Yuan; Cho, Kyung-Hoon; Heo, Jin S.; Priya, Shashank

    2015-09-01

    Two different templates (<001> Ba6Ti17O40 and <111> BaTiO3) were used for synthesizing <111> textured tetragonal 0.6Pb(Mg1/3Nb2/3)O3-0.4PbTiO3(PMN-40PT) ceramics. It was found that a texture degree of 95% along <111> direction can be achieved by using only 1 vol. % <111> BaTiO3 template due to its high chemical stability in the PMN-40PT matrix. The textured PMN-40PT ceramics with tetragonal structure exhibited an excellent temperature stability of piezoelectric properties due to the absence of intermediate phase transitions between room temperature and the Curie temperature. Unlike the single crystal counterpart, the effect of <111> grain orientation in the textured PMN-40PT ceramic on enhancing the macroscopic piezoelectric response was not significant in spite of its giant local piezoresponse. We provide detailed discussions on the nature of piezoelectric response in the <111> textured tetragonal PMN-40PT ceramic with "3T" engineered domain configuration and resultant strategy to realize high performance piezoelectric ceramics.

  4. Microstructure, dielectric and piezoelectric properties of (Pb1-xSrx)Nb1.96Ti0.05O6 ceramics

    NASA Astrophysics Data System (ADS)

    Yuan, Jing-jing; Chen, Xiao-ming; Zhou, Jian-ping; Liu, Peng

    2014-09-01

    (Pb1-xSrx)Nb1.96Ti0.05O6 with 2 wt% excess PbO (x = 0, 0.02, 0.04, 0.06, 0.08) piezoelectric ceramics with high Curie temperature were fabricated via the conventional solid state reaction method. Effects of Sr2+ amount on crystallite structure, microstructure, dielectric and piezoelectric properties were studied. The substitution of Sr2+ ions for Pb2+ ions is effective to lower sintering temperatures. X-ray diffraction patterns indicate that all ceramics form the single orthorhombic ferroelectric phase. The doping of Sr2+ ions facilitates improving densification of the ceramics. Grain size and lattice parameters of the ceramics vary with the change of the Sr2+ contents. Both Curie temperature and maximum dielectric constant change with increasing the Sr2+ amounts. The dielectric constant data were also studied using the Curie-Weiss law and modified Curie-Weiss law. The ceramic with x = 0.04 possesses excellent piezoelectric and dielectric properties, presenting a high potential to be used in high-temperature applications as piezoelectric transducers.

  5. An analysis of lead-free (Bi0.5Na0.5)0.915-(Bi0.5K0.5)0.05Ba0.02Sr0.015TiO3 ceramic for efficient refrigeration and thermal energy harvesting

    NASA Astrophysics Data System (ADS)

    Vats, Gaurav; Vaish, Rahul; Bowen, Chris R.

    2014-01-01

    This article demonstrates the colossal energy harvesting capability of a lead-free (Bi0.5Na0.5)0.915-(Bi0.5K0.5)0.05Ba0.02Sr0.015TiO3 ceramic using the Olsen cycle. The maximum harvestable energy density estimated for this system is found to be 1523 J/L (1523 kJ/m3) where the results are presented for extreme ambient conditions of 20-160 °C and electric fields of 0.1-4 MV/m. This estimated energy density is 1.7 times higher than the maximum reported to date for the lanthanum-doped lead zirconate titanate (thin film) system. Moreover, this study introduces a generalized and effective solid state refrigeration cycle in contrast to the ferroelectric Ericson refrigeration cycle. The cycle is based on a temperature induced polarization change on application of an unipolar electric field to ferroelectric ceramics.

  6. Enhanced energy-storage properties of (1-x)[(1-y)(Bi0.5Na0.5)TiO3-y(Bi0.5K0.5)TiO3]-x(K0.5Na0.5)NbO3 lead-free ceramics

    NASA Astrophysics Data System (ADS)

    Hao, Jigong; Xu, Zhijun; Chu, Ruiqing; Li, Wei; Juan, Du; Peng, Fu

    2015-02-01

    In this work, we designed a series of compositions within peudocubic region based on ternary (1-x)[(1-y)(Bi0.5Na0.5)TiO3-y(Bi0.5K0.5)TiO3]-x(K0.5Na0.5)NbO3 (BNKT100y-xKNN) system for energy storage applications. Results showed that the KNN substitution into BNKT100y induced a significant disruption of the ferroelectric order, and tended to enhance the energy storage density of the ceramics. With the external electric field, the energy storage density increased drastically, and a maximum value of 1.20 J/cm3 at 100 kV/cm was achieved in BNKT100y-xKNN (y=0, x=0.16) samples. Furthermore, BNKT100y-xKNN (y=0, x=0.16) ceramics not only exhibited high energy density but also possessed fatigue-free behavior and temperature-independent characteristic. Temperature-dependent structural analysis suggested that the good energy-storage properties insensitive to temperature can be ascribed to the stable relaxor pseudocubic (antiferroelectric-like) phase over a wide temperature range. These results indicate that BNKT100y-xKNN system should be a promising lead-free material for energy-storage capacitor application.

  7. An analysis of lead-free (Bi{sub 0.5}Na{sub 0.5}){sub 0.915}-(Bi{sub 0.5}K{sub 0.5}){sub 0.05}Ba{sub 0.02}Sr{sub 0.015}TiO{sub 3} ceramic for efficient refrigeration and thermal energy harvesting

    SciTech Connect

    Vats, Gaurav; Vaish, Rahul; Bowen, Chris R.

    2014-01-07

    This article demonstrates the colossal energy harvesting capability of a lead-free (Bi{sub 0.5}Na{sub 0.5}){sub 0.915}-(Bi{sub 0.5}K{sub 0.5}){sub 0.05}Ba{sub 0.02}Sr{sub 0.015}TiO{sub 3} ceramic using the Olsen cycle. The maximum harvestable energy density estimated for this system is found to be 1523 J/L (1523 kJ/m{sup 3}) where the results are presented for extreme ambient conditions of 20–160 °C and electric fields of 0.1–4 MV/m. This estimated energy density is 1.7 times higher than the maximum reported to date for the lanthanum-doped lead zirconate titanate (thin film) system. Moreover, this study introduces a generalized and effective solid state refrigeration cycle in contrast to the ferroelectric Ericson refrigeration cycle. The cycle is based on a temperature induced polarization change on application of an unipolar electric field to ferroelectric ceramics.

  8. Enhanced High Temperature Piezoelectrics Based on BiScO3-PbTiO3 Ceramics

    NASA Technical Reports Server (NTRS)

    Sehirlioglu, Alp; Sayir, Ali; Dynys, Fred

    2009-01-01

    High-temperature piezoelectrics are a key technology for aeronautics and aerospace applications such as fuel modulation to increase the engine efficiency and decrease emissions. The principal challenge for the insertion of piezoelectric materials is the limitation on upper use temperature which is due to low Curie-Temperature (TC) and increasing electrical conductivity. BiScO3-PbTiO3 (BS-PT) system is a promising candidate for improving the operating temperature for piezoelectric actuators due to its high TC (greater than 400 C). Bi2O3 was shown to be a good sintering aid for liquid phase sintering resulting in reduced grain size and increased resistivity. Zr doped and liquid phase sintered BS-PT ceramics exhibited saturated and square hysteresis loops with enhanced remenant polarization (37 microC per square centimeter) and coercive field (14 kV/cm). BS-PT doped with Mn showed enhanced field induced strain (0.27% at 50kV/cm). All the numbers indicated in parenthesis were collected at 100 C.

  9. Promotion of piezoelectric properties of lead zirconate titanate ceramics with (Zr,Ti) partially replaced by Nb 2O 5

    NASA Astrophysics Data System (ADS)

    Chen, Bing-Huei; Huang, Cheng-Liang; Wu, Long

    2004-12-01

    This study investigated the correlation of sintering effects on piezoelectric properties of Nb modified lead zirconate titanate (PZT) piezoceramics produced by the conventional solid reaction sintering. Samples were prepared at a composition Zr/Ti=53/47, contiguous to a morphotropic phase boundary (MPB) for 1 mol% Nb2O5. Replacement of Ti+4 by Nb+5 in such perovskite type solid solutions was accomplished by the creation of cation vacancies. These created vacancies seemed to facilitate material transport and benefit sintering. Calcined at 850 °C/2 h and sintered at 1250 °C/2 h, the PZT ceramics yielded a minimum value of the mechanical quality factor (Qm) 50, and exhibited a maximum electromechanical coupling factor κp 0.62, in accordance with the relationship between the mechanical quality factor and electromechanical coupling factor. In addition, during the sintering process a piezoelectric charge constant at d33 was found to be of 385 pC/N. It was noted that the fundamental resonance frequency was around 200 kHz, which was suitable for piezoelectric nebulizer (fluid atomizer), ultrasonic cleaning transducer applications.

  10. Plate-like structure health monitoring based on ultrasonic guided wave technology by using bonded piezoelectric ceramic wafers

    NASA Astrophysics Data System (ADS)

    Liu, Zenghua; Zhao, Jichen; He, Cunfu; Wu, Bin

    2008-11-01

    Piezoelectric ceramic wafers are applied for the excitation and detection of ultrasonic guided waves to determine the health state of plate-like structures. Two PZT wafers, whose diameter is 11mm and thickness is 0.4mm respectively, are bonded permanently on the surface of a 1mm thick aluminum plate. One of these wafers is actuated by sinusoidal tone burst at various frequencies ranging from 100kHz to 500kHz, the other one is used as a receiver for acquiring ultrasonic guided wave signals. According to the amplitudes and shapes of these received signals, guided wave modes and their proper frequency range by using these wafers are determined. For the improvement of the signal-to-noise ratio, the Daubechies wavelet of order 40 is used for signal denoising as the mother wavelet. Furthermore, the detection of an artificial cylindrical through-hole defect is achieved by using S0 at 300kHz. Experimental results show that it is feasible and effective to detect defects in plate-like structures based on ultrasonic guided wave technology by using bonded piezoelectric ceramic wafers.

  11. Label-free detection of endocrine disrupting chemicals by integrating a competitive binding assay with a piezoelectric ceramic resonator.

    PubMed

    Hu, Liang-sheng; Fong, Chi-Chun; Zou, Lan; Wong, Wing-Leung; Wong, Kwok-Yin; Wu, Rudolf S S; Yang, Mengsu

    2014-03-15

    A piezoelectric biosensor for detection of endocrine disrupting chemicals (EDCs) was developed by incorporating chemical/biochemical recognition elements on the ceramic resonator surface for competitive binding assays. A facile electrodeposition was employed to modify the sensor surface with Au nanoparticles, which increased the surface area and enhanced the binding capacity of the immobilized probes. Thiol-labeled long chain hydrocarbon with bisphenol A (BPA) as head group was synthesized and self-assembled on the Au nanoparticle surface as the sensing probes, which showed a linear response upon the binding of estrogen receptor (ER-?) ranging from 1 to 30 nM. Detection of estrone, 17?-estradiol and BPA was achieved by integrating a competitive binding assay with the piezoelectric sensor. In this detection scheme, different concentrations of EDCs were incubated with 30 nM of ER-?, and the un-bounded ER-? in the solution was captured by the probes immobilized on the ceramic resonator, which resulted in the frequency changes for different EDCs. The biosensor assay exhibited a linear response to EDCs with a low detection limit of 2.4-2.9 nM (S/N=3), and required only a small volume of sample (1.5 l) with the assay time of 2h. The performance of the biosensor assay was also evaluated for rapid and facile determination of EDCs of environmental relevant concentrations in drinking water and seawater, and the recovery rate was in the range between 94.7% and 109.8%. PMID:24201004

  12. Synthesis of Lead-Free Air-Sintered BaTiO3-(Bi1/2Na1/2)TiO3-Based Positive-Temperature-Coefficient of Resistance Ceramics by Ca Addition and the Defect Chemistry of Semiconductivity

    NASA Astrophysics Data System (ADS)

    Zubair, Mohammad A.; Takeda, Hiroaki; Hoshina, Takuya; Tsurumi, Takaaki

    2013-09-01

    Lead-free n-type [Ba0.9(Ba1/2Na1/2)0.1]TiO3-based positive-temperature-coefficient of resistance (PTC) ceramics with TC > 158 °C were successfully synthesized by addition of 2-4 mol % CaO through a mixed oxide fabrication route and adopting an atmospheric sintering condition. All ceramics exhibited single phase BaTiO3 structure with 64.21(1) Å3 cell volume. A drop in room-temperature resistivity (ρRT) by 7-8 orders magnitude in presence of the CaO was attributed to residual Ba2+ site Bi3+ acting as donor defect owing to filling up of vacancies introduced by the preferential evaporation of Na+ over Bi3+ by Ca2+. Increases in ρRT and the maximum PTC resistivity (ρmax) from 0.316 to 2.11 kΩ.cm and from 0.085 to 2.94 MΩ.cm, respectively, with 2 to 4 mol % CaO addition were attributed to the gradual incorporation of Ca2+ into both Ba2+ and Ti4+ sites, which oxidized the electron hopping centers (Ti3+) through the generation of holes. The optimum CaO content (3.5 mol %), sintering time (2 h) and temperature (1160 °C) were established to achieve [Ba0.9(Ba1/2Na1/2)0.1] TiO3-based semiconducting PTC ceramics by adopting an atmospheric sintering environment.

  13. Ferroelectric, piezoelectric, and dielectric properties of BiScO{sub 3}-PbTiO{sub 3}-Pb(Cd{sub 1/3}Nb{sub 2/3})O{sub 3} ternary high temperature piezoelectric ceramics

    SciTech Connect

    Zhao Tianlong; Chen Jianguo; Dong Shuxiang; Wang Chunming; Yu Yang

    2013-07-14

    (0.95-x)BiScO{sub 3}-xPbTiO{sub 3}-0.05Pb(Cd{sub 1/3}Nb{sub 2/3})O{sub 3} (BS-xPT-PCN) high temperature piezoelectric ceramics near the morphotropic phase boundary (MPB) have been synthesized by traditional solid-state reaction methods. The microstructural morphology, phase structure, and electrical properties of BS-xPT-PCN ceramics were investigated in detail. X-ray diffraction analysis indicated BS-xPT-PCN ceramics have a pure perovskite structure. The coexistence of rhombohedral and tetragonal phases at MPB composition enhanced the polarizability by the coupling between two dynamically equivalent energy states, resulting in the improved piezoelectric and ferroelectric properties at MPB vicinity. The BS-xPT-PCN (x = 0.60) ceramics possess the optimal piezoelectric and ferroelectric properties with d{sub 33} = 505pC/N, k{sub p} = 55.9%, k{sub t} = 36.5%, strain = 0.23% (under the electric field 37.5 kV/cm), and P{sub r} = 39.7 {mu}C/cm{sup 2}. High temperature dielectric behaviors showed diffuse phase transition in BS-xPT-PCN ceramics. The Curie temperature T{sub c} was found to increase from 371 Degree-Sign C to 414 Degree-Sign C with x increasing from 0.58 to 0.62. All these results together with the good thermal stabilities make the BS-xPT-PCN ceramics promising candidates for high temperature piezoelectric applications.

  14. Effects of Fe2O3 Additive on the Structure and Piezoelectric Properties of PZT-PFW-PMN Ceramics

    NASA Astrophysics Data System (ADS)

    Zong, Ximei; Yang, Zupei

    2015-01-01

    Quaternary piezoelectric ceramics 0.90Pb0.95Sr0.05(Zr0.52Ti0.48)O3-0.03Pb(Fe2/3W1/3)O3-0.07Pb(Mn1/3Nb2/3)O3 (PZT-PFW-PMN) + 0.2 wt.% CeO2 + x wt.% Fe2O3 ( x = 0.0 to 0.20) were prepared by the conventional solid-state method. The effects of Fe2O3 addition on the structure and electrical properties of the system were systematically investigated. The results revealed that the phase structure of all samples was tetragonal phase and the piezoelectric and dielectric properties were significantly promoted with increasing Fe2O3 addition. The coercive field E C and internal bias field E i were found to increase with increasing Fe2O3 content. As a result, addition of 0.05 wt.% Fe2O3 for this system resulted in excellent electrical properties, with the following parameter values: Q m = 1839, K p = 0.61, d 33 = 382 pC/N, ɛ r = 1823, tan δ = 0.0054, P r = 19.26 μC/cm2, E C = 13.28 kV/cm, and E i = 0.76 kV/cm. The results indicate that the Fe2O3-modified PZT-PFW-PMN ceramics exhibited favorable properties and could be good candidates for use in high-power piezoelectric transformer applications.

  15. High strain in (K,Na)NbO3-based lead-free piezoceramics.

    PubMed

    Tao, Hong; Wu, Jiagang; Xiao, Dingquan; Zhu, Jianguo; Wang, Xiangjian; Lou, Xiaojie

    2014-11-26

    A high strain is important for practical applications of piezoelectric actuators. Here we reported a high strain in the (K,Na)NbO3 -based ceramics by doping alkaline earths or transition metals. The ceramics possess a high strain (?0.29%) as well as a large converse piezoelectric coefficient (d33*) up to 688 pm/V, which almost matches that of PZT4 ceramics. The obtained d33* is high for nontextured (K,Na)NbO3-based ceramics. In addition, a higher d33 value (340-407 pC/N) was also attained in the ceramics. Enhanced d33 and d33* values of this work should be attributed to the multiphase coexistence's effect induced by alkaline earths or transition metals. We believe that our research can benefit the developments of (K,Na)NbO3 ceramics and widen their applications range. PMID:25384464

  16. Unique Piezoelectric Properties of the Monoclinic Phase in Pb (Zr ,Ti )O3 Ceramics: Large Lattice Strain and Negligible Domain Switching

    NASA Astrophysics Data System (ADS)

    Fan, Longlong; Chen, Jun; Ren, Yang; Pan, Zhao; Zhang, Linxing; Xing, Xianran

    2016-01-01

    The origin of the excellent piezoelectric properties at the morphotropic phase boundary is generally attributed to the existence of a monoclinic phase in various piezoelectric systems. However, there exist no experimental studies that reveal the role of the monoclinic phase in the piezoelectric behavior in phase-pure ceramics. In this work, a single monoclinic phase has been identified in Pb (Zr ,Ti )O3 ceramics at room temperature by in situ high-energy synchrotron x-ray diffraction, and its response to electric field has been characterized for the first time. Unique piezoelectric properties of the monoclinic phase in terms of large intrinsic lattice strain and negligible domain switching have been observed. The extensional strain constant d33 and the transverse strain constant d31 are calculated to be 520 and -200 pm /V , respectively. These large piezoelectric coefficients are mainly due to the large intrinsic lattice strain, with very little extrinsic contribution from domain switching. The unique properties of the monoclinic phase provide new insights into the mechanisms responsible for the piezoelectric properties at the morphotropic phase boundary.

  17. Piezoelectric activity of relaxor-PbTiO3 based single crystals and polycrystalline ceramics at cryogenic temperatures: Intrinsic and extrinsic contributions

    PubMed Central

    Li, Fei; Zhang, Shujun; Xu, Zhuo; Wei, Xiaoyong; Luo, Jun; Shrout, Thomas R.

    2010-01-01

    The piezoelectric activity in [001] poled Pb(In1∕2Nb1∕2)O3–Pb(Mg1∕3Nb2∕3)O3–PbTiO3 crystals was investigated as a function of composition and temperature. The level of intrinsic and∕or extrinsic contribution to the total piezoelectric activity was analyzed using Rayleigh method. The results revealed that though 95% of the observed piezoelectric activity in rhombohedral crystals was intrinsic (lattice), the properties decreased significantly with decreasing temperature. At −150 °C, the piezoelectric response decreased by 40%–55% for the compositions close to a morphotropic phase boundary (rhombohedral-monoclinic or monoclinic-tetragonal), while decreasing only 20%–30% for the compositions in the rhombohedral region. The piezoelectric properties of Pb(Mg1∕3Nb2∕3)O3–PbTiO3 polycrystalline ceramics were found to decrease by 75%, showing both intrinsic and extrinsic contributions play important role in the reduction in piezoelectricity at cryogenic temperatures for ceramics. PMID:20531980

  18. Unique Piezoelectric Properties of the Monoclinic Phase in Pb(Zr,Ti)O_{3} Ceramics: Large Lattice Strain and Negligible Domain Switching.

    PubMed

    Fan, Longlong; Chen, Jun; Ren, Yang; Pan, Zhao; Zhang, Linxing; Xing, Xianran

    2016-01-15

    The origin of the excellent piezoelectric properties at the morphotropic phase boundary is generally attributed to the existence of a monoclinic phase in various piezoelectric systems. However, there exist no experimental studies that reveal the role of the monoclinic phase in the piezoelectric behavior in phase-pure ceramics. In this work, a single monoclinic phase has been identified in Pb(Zr,Ti)O_{3} ceramics at room temperature by insitu high-energy synchrotron x-ray diffraction, and its response to electric field has been characterized for the first time. Unique piezoelectric properties of the monoclinic phase in terms of large intrinsic lattice strain and negligible domain switching have been observed. The extensional strain constant d_{33} and the transverse strain constant d_{31} are calculated to be 520 and -200??pm/V, respectively. These large piezoelectric coefficients are mainly due to the large intrinsic lattice strain, with very little extrinsic contribution from domain switching. The unique properties of the monoclinic phase provide new insights into the mechanisms responsible for the piezoelectric properties at the morphotropic phase boundary. PMID:26824565

  19. Feasibility study of thermal energy harvesting using lead free pyroelectrics

    NASA Astrophysics Data System (ADS)

    Karim, Hasanul; Sarker, Md Rashedul H.; Shahriar, Shaimum; Arif Ishtiaque Shuvo, Mohammad; Delfin, Diego; Hodges, Deidra; (Bill Tseng, Tzu-Liang; Roberson, David; Love, Norman; Lin, Yirong

    2016-05-01

    Energy harvesting has significant potential for applications in energizing wireless sensors and charging energy storage devices. To date, one of the most widely investigated materials for mechanical and thermal energy harvesting is lead zirconate titanate (PZT). However, lead has detrimental effects on the environment and on health. Hence, alternative materials are required for this purpose. In this paper, a lead free material, lithium niobate (LNB) is investigated as a potential material for pyroelectric energy harvesting. Although its theoretical pyroelectric properties are lower compared to PZT, it has better properties than other lead free alternatives such as ZnO. In addition, LNB has a high Curie temperature of about 1142 °C, which makes it applicable for high temperature energy harvesting, where other pyroelectric ceramics are not suitable. Herein, an energy harvesting and storage system composed of a single crystal LNB and a porous carbon-based super-capacitor was investigated. It is found that with controlled heating and cooling, a single wafer of LNB (75 mm diameter and 0.5 mm thickness) could generate 437.72 nW cm–3 of power and it could be used to charge a super-capacitor with a charging rate of 2.63 mV (h cm3)–1.

  20. Dielectric and piezoelectric properties of Bi2O3 added (Pb,Ca,Sr)(Ti,Mn,Sb)O3 ceramics sintered at low temperature

    NASA Astrophysics Data System (ADS)

    Kim, Dohyung; Yoo, Juhyun; Kim, Insung; Song, Jaesung

    2009-03-01

    In this study, in order to develop low temperature sintering ceramics for a thickness mode multilayer piezoelectric transformer, (Pb,Ca,Sr)(Ti,Mn,Sb)O3 ceramics were fabricated using Na2CO3, Li2CO3, MnO2, and Bi2O3 as sintering aids at 870, 900, and 930 °C. Their respective dielectric and piezoelectric properties were investigated according to the amount of Bi2O3 addition. At the sintering temperature of 900 °C, the optimum value was shown for the density of 6.94 g/cm3, thickness vibration mode electromechanical coupling factor (henceforth, kt) of 0.497, thickness vibration mode mechanical quality factor (henceforth, Qmt) of 3162, and dielectric constant (henceforth, ɛr) of 209 for thickness mode multilayer piezoelectric transformer application.

  1. Electromechanical properties of A-site (LiCe)-modified sodium bismuth titanate (Na{sub 0.5}Bi{sub 4.5}Ti{sub 4}O{sub 15}) piezoelectric ceramics at elevated temperature

    SciTech Connect

    Wang Chunming; Wang Jinfeng; Zhang Shujun; Shrout, Thomas R.

    2009-05-01

    The Aurivillius-type bismuth layer-structured (NaBi){sub 0.46}(LiCe){sub 0.04}Bi{sub 4}Ti{sub 4}O{sub 15} (NBT-LiCe) piezoelectric ceramics were synthesized using conventional solid-state processing. Phase analysis was performed by x-ray diffraction and microstructural morphology was assessed by scanning electron microscopy. The dielectric, piezoelectric, ferroelectric, and electromechanical properties of NBT-LiCe ceramics were investigated. The piezoelectric activities were found to be significantly enhanced compared to NBT ceramics, which can be attributed to the lattice distortion and the presence of bismuth vacancies. The dielectric and electromechanical properties of NBT-LiCe ceramics at elevated temperature were investigated in detail. The excellent piezoelectric, dielectric, and electromechanical properties, coupled with high Curie temperature (T{sub c}=660 deg. C), demonstrated that the NBT-LiCe ceramics are the promising candidates for high temperature applications.

  2. Microstructure and electrical properties in W/Nb co-doped Aurivillius phase Bi{sub 4}Ti{sub 3}O{sub 12} piezoelectric ceramics

    SciTech Connect

    Peng, Zhihang; Chen, Qiang; Chen, Yu; Xiao, Dingquan; Zhu, Jianguo

    2014-11-15

    Highlights: • W/Nb codoped BIT ceramics were prepared by the mixed oxides route. • High nd{sup 0} electronic configuration of W/Nb reduces the lattice distortion and T{sub C}. • Oxygen vacancy is responsible for dielectric relaxation and DC conduction process. • W/Nb additives significantly enhanced the piezoelectric coefficient d{sub 33} value. • BWNb-10 ceramics possessed large remnant polarization and a wide sintering window. - Abstract: Aurivillius-type Bi{sub 4}Ti{sub 3-x}W{sub x/2}Nb{sub x/2}O{sub 12} ceramics were prepared by a conventional solid-state sintering method. The XRD patterns demonstrated that all compositions were a single three layered crystalline structure, involving a reduction of lattice distortion with an increase in W/Nb doping level. The electrical properties including dielectric, electrical conduction and piezoelectric properties were tailored by W/Nb additives. The Curie-temperature decreased, whereas the electrical resistivity drastically increased with introduction of W/Nb donor dopants. As a result, a high electric field can be applied during the poling process. The Bi{sub 4}Ti{sub 2.9}W{sub 0.05}Nb{sub 0.05}O{sub 12} ceramics exhibited optimum piezoelectric coefficient (d{sub 33} ∼22.8 pC/N), large remnant polarization (2P{sub r} ∼26.8 μC/cm{sup 2} @ 200 °C) together with a high Curie temperature (T{sub C} ∼635 °C). Furthermore, this composition possessed a wide sintering window with outstanding piezoelectric properties. These parameters indicate that Bi{sub 4}Ti{sub 2.9}W{sub 0.05}Nb{sub 0.05}O{sub 12}-based ceramic is a promising candidate for high temperature piezoelectric applications.

  3. Solid-state conversion of (Na1/2Bi1/2)TiO3-BaTiO3-(K1/2Na1/2)NbO3 single crystals and their piezoelectric properties

    NASA Astrophysics Data System (ADS)

    Park, Ji-Hoon; Lee, Ho-Yong; Kang, Suk-Joong L.

    2014-06-01

    Piezoelectric ceramic with a composition of (94 - x)(Na1/2Bi1/2)TiO3-6BaTiO3-x(K1/2Na1/2)NbO3 (NBT-BT-xKNN) is a promising lead-free piezoelectric material for actuator applications because of its giant electric-field-induced strains, which are comparable with that of soft Pb(ZrxTi1-x)O3 (PZT) ceramics. Using the solid-state single crystal growth method, we succeeded in fabricating usable single crystals of NBT-BT-3KNN (6 mm 6 mm 8 mm size) with a uniform chemical composition. The room temperature piezoelectric properties of ?001?, ?110?, and ?111? oriented single crystals were measured. Single crystals showed strong anisotropic strain characteristics. In particular, ?001? oriented single crystals had excellent piezoelectric properties with small hysteresis and a high strain of 0.57% at 7 kV/mm. In addition, the fabricated single crystals exhibited a high converse piezoelectric constant, Smax/Emax, of over 1000 pm/V at 4 kV/mm. These values are greater than those reported for any lead-containing and lead-free ceramics and comparable with those of lead-based single crystals. Our investigation demonstrates the solid-state conversion of lead-free single crystals and their practical usability in replacement of lead-based materials.

  4. Effect of Lanthanum Doping on Ferroelectric and Strain Properties of 0.96Bi1/2(Na0.84K0.16)1/2TiO3-0.04SrTiO3 Lead-Free Ceramics

    NASA Astrophysics Data System (ADS)

    Tran, Vu Diem Ngoc; Ullah, Aman; Dinh, Thi Hinh; Lee, Jae-Shin

    2016-05-01

    Lead-free 0.96[Bi1/2(Na0.84K0.16)1/2](1- x)La x TiO3-0.04SrTiO3 (BNKTLa x-ST, with x = 0.00, 0.01, 0.02, 0.03, 0.04, and 0.05) ceramics have been synthesized using a conventional solid-state reaction method and their phase transition, dielectric, ferroelectric, and strain properties investigated. X-ray diffraction patterns revealed formation of pure perovskite phase. A phase transition from coexistence of rhombohedral and tetragonal to a pseudocubic phase was observed at x = 0.02. Polarization and bipolar strain hysteresis loops indicated that the ferroelectric order (FE) of BNKT-ST is significantly disrupted by lanthanum doping. The destabilization of the FE order results in degradation of the remanent polarization, coercive field, depolarization temperature ( T d), electromechanical coupling factor ( k p), and static d 33, accompanied by large electric-field-induced strain of 0.34% at 60 kV/cm with normalized strain of d 33 * = S max/ E max = 600 pm/V at a critical composition of around x = 0.02.

  5. Large electrostrictive effect and bright upconversion luminescence in Er-modified 0.92(Bi0.5Na0.5)TiO3-0.08(Ba0.90Ca0.10)(Ti0.92Sn0.08)O3 lead-free ceramics

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaoli; Wu, Meihua; Diao, Wenxin; Zhang, Bing; Hao, Jigong; Xu, Zhijun; Chu, Ruiqing

    2015-10-01

    In this study, a new lead-free luminescent electrostrictive material has been obtained by introducing trivalent Er3+ as the activator into 0.92(Bi0.5Na0.5)TiO3-0.08(Ba0.90Ca0.10)(Ti0.92Sn0.08)O3 (BNT-0.08BCST). A high, purely electrostrictive effect (the electrostrictive coefficient Q33 reaches up to 0.028 m4/C2) with exceptionally good fatigue resistance (up to 106 cycles) and thermostability (25-140 °C) is obtained in 0.2 mol%Er-modified BNT-0.08BCST ceramics. Besides the excellent electrostrictive properties, Er3+-modified BNT-0.08BCST samples exhibit a strong green-red upconversion emission, and the emission intensities are strongly dependent on the doping concentration, which reaches the optimal value as the doping concentration is 0.4 mol%. These results suggest that this kind of material may have potential application as a multifunctional device by integrating its excellent upconversion luminescence and electrostrictive properties.

  6. Processing and enhanced piezoelectric properties of highly oriented compositionally modified Pb(Zr,Ti)O3 ceramics fabricated by magnetic alignment

    NASA Astrophysics Data System (ADS)

    Miwa, Yasunari; Kawada, Shinichiro; Kimura, Masahiko; Omiya, Suetake; Kubodera, Noriyuki; Ando, Akira; Suzuki, Tohru S.; Uchikoshi, Tetsuo; Sakka, Yoshio

    2015-04-01

    Highly oriented compositionally modified Pb(Zr,Ti)O3 (PZT) ceramics were successfully obtained by slip casting in a high magnetic field. PZT is a well-known superior ceramic with the highest piezoelectric properties, and these properties have been expected to be further improved through crystalline orientation. However, highly oriented PZT ceramics fabricated by slip casting in a high magnetic field have never been reported. We obtained oriented ceramics using compositionally modified PZT with Pb(Ni,Nb)O3, and their Lotgering factor was 0.77. The electromechanical coupling coefficient (k31) increased by 30%, and an extremely high value of 0.44 was achieved for the oriented ceramics.

  7. Piezoelectric Properties of Pb0.98Bi0.02Zr0.51Ti0.48Zn0.01O3 Ceramics

    NASA Astrophysics Data System (ADS)

    He, Wenze; Yu, Jian

    2011-02-01

    On the basis of eutectic behavior of PbTiO3-PbZrO3-Bi(Zn0.5Ti0.5)O3 ternary system, perovskite-structured Pb0.98Bi0.02Zr0.51Ti0.48Zn0.01O3 ceramics were able to be prepared using conventional electronic ceramic processing at low sintering temperature compatible with Ag as inner electrode materials, promising for co-firing technology to fabricate monolithic multilayer piezoelectric transducers. The dependence of its piezoelectric properties on sintering temperature and various dopants were investigated experimentally and a piezoelectric property with dielectric constant of ɛ33T/ɛ0=1190, dielectric loss of tan δ=0.6%, piezoelectric coefficient of d33=270 pC/N, planar coupling coefficient of kp=0.54, thickness coupling coefficient of kt=0.46 and Curie temperature of Tc=346 °C was obtained for the 0.5% Co-doped Pb0.98Bi0.02Zr0.51Ti0.48Zn0.01O3 ceramics sintered at 950 °C.

  8. Piezoelectric properties of nonstoichiometric Sr1-xBi2+2x/3Ta2O9 ceramics

    NASA Astrophysics Data System (ADS)

    Jain, Rajni; Chauhan, Arun Kumar Singh; Gupta, Vinay; Sreenivas, K.

    2005-06-01

    The effect of poling on the structural, dielectric, and piezoelectric properties has been investigated for sol-gel-derived strontium bismuth tantalate (SBT) [Sr1-xBi2+2x/3Ta2O9] ceramics with x =0.0,0.15,0.30,0.45. The dielectric and ferroelectric properties are found to improve with increase in x up to 0.3. Beyond x >0.3 the properties are found to degrade due to the limited solid solubility and the presence of a mixed phase of bismuth tantalate (BiTaO4) is detected with x =0.45. Poling treatment reduces the dielectric dispersion and dielectric loss in the frequency range (0.1-100kHz). The resonance and antiresonance frequencies increase with increase in x (x=0-0.30), and the corresponding minimum impedance decreases. The measured coupling coefficients (kp) are small (0.0967-0.1) for x =0-0.30, and the electromechanical quality factor (Qm=915) is a maximum for the Sr0.7Bi2.2Ta2O9 composition (x=0.30). The estimated piezoelectric charge coefficient (d31) and piezoelectric voltage coefficient (g31) are 5.2pC/N and 5.8×10-3Vm/N, respectively. The positive values of d31 and g31 and the low dielectric permittivity of SBT yield a high value for the hydrostatic coefficients, despite the low charge coefficient of d33=24pC/N. The maximum values of charge coefficient (dh=34pC/N) and voltage coefficient (gh=39×10-3Vm/N) are obtained for Sr0.7Bi2.2Ta2O9 composition, and the estimated hydrostatic figure of merit (dhgh×10-15=1215m2/N) is high.

  9. Processing of Fine-Scale Piezoelectric Ceramic/Polymer Composites for Sensors and Actuators

    NASA Technical Reports Server (NTRS)

    Janas, V. F.; Safari, A.

    1996-01-01

    The objective of the research effort at Rutgers is the development of lead zirconate titanate (PZT) ceramic/polymer composites with different designs for transducer applications including hydrophones, biomedical imaging, non-destructive testing, and air imaging. In this review, methods for processing both large area and multifunctional ceramic/polymer composites for acoustic transducers were discussed.

  10. High-Performance Lead-Free Piezoceramics with High Curie Temperatures.

    PubMed

    Lee, Myang Hwan; Kim, Da Jeong; Park, Jin Su; Kim, Sang Wook; Song, Tae Kwon; Kim, Myong-Ho; Kim, Won-Jeong; Do, Dalhyun; Jeong, Il-Kyoung

    2015-11-01

    A bismuth ferrite and barium titanate solid solution compound can achieve good piezoelectric properties with a high Curie temperature when fabricated with low-temperature sintering followed by a water-quenching process, with no complicated grain alignment processes performed. By adding the super-tetragonal bismuth gallium oxide to the compound, the piezoelectric properties are as good as those of lead zirconate titanate ceramics. PMID:26444562

  11. Strong piezoelectric anisotropy d15/d33 in ?111? textured Pb(Mg1/3Nb2/3)O3-Pb(Zr,Ti)O3 ceramics

    NASA Astrophysics Data System (ADS)

    Yan, Yongke; Priya, Shashank

    2015-08-01

    The shear mode piezoelectric properties of Pb(Mg1/3Nb2/3)O3-Pb(Zr,Ti)O3 (PMN-PZT) ceramic with 72% ?111? texture were investigated. The piezoelectric anisotropic factor d15/d33 was as high as 8.5 in ?111? textured ceramic as compared to 2.0 in random counterpart. The high d15/d33 indicates the "rotator" ferroelectric characteristics of PMN-PZT system and suggests that the large shear piezoelectric response contributes towards the high longitudinal piezoelectric response (d33) in non-polar direction (d33 = 1100 pC/N in ?001? textured ceramic vs. d33 = 112 pC/N in ?111? textured ceramic).

  12. Modeling of piezoelectric ceramic vibrators including thermal effects. Part IV. Development and experimental evaluation of a bond graph model of the thickness vibrator

    SciTech Connect

    Moon, W.; Busch-Vishniac, I.J.

    1997-03-01

    This article develops a model of the piezoelectric ceramic vibrator which includes thermal energy exchange on an equal footing with the electrical and mechanical energy. By use of an isentropically linear model for the material and the bond graph models for a piezoelectric thickness vibrator and heat conduction previously developed by the authors, a thermodynamically complete model is developed. For a simple case, the predicted results from the developed model are compared with the results from experiments. Predictions are found to compare very favorably with these measurements. {copyright} {ital 1997 Acoustical Society of America.}

  13. Ultrahigh temperature Bi3Ti0.96Sc0.02Ta0.02NbO9-based piezoelectric ceramics

    NASA Astrophysics Data System (ADS)

    Gai, Zhi-Gang; Wang, Jin-Feng; Sun, Wen-bin; Wang, Chun-Ming; Zhao, Ming-Lei; Sun, Shang-Qian; Ming, Bao-Quan; Qi, Peng; Zheng, Li-mei; Du, Juan; Zhang, Shujun; Shrout, Thomas R.

    2008-07-01

    The effect of (Sc,Ta,Ce) doping on the properties of Bi3TiNbO9 (BTNO)-based ceramics was investigated. The cerium modification greatly improves the piezoelectric activity of Bi3(Ti0.96Sc0.02Ta0.02)NbO9-based ceramics and significantly decreases the dielectric dissipation. The d33 of Bi3Ti0.96Sc0.02Ta0.02NbO9+x wt %CeO2 (x =0.35) was found to be 18 pC/N, the highest value among the BTNO-based ceramics and almost three times as much as the reported d33 values of the pure BTNO ceramics (˜6 pC/N). The modification increased the resistivity ρ of the samples extremely, resolving the low resistivity problem for high temperature applications. The dielectric spectroscopy shows that the TC for all the ceramics is higher than 900 °C. The mechanical quality factor Q and planar coupling factors kp and kt of Bi3Ti0.96Sc0.02Ta0.02NbO9+0.35 wt %CeO2 ceramic were found to be 2835, 9%, and 23%, respectively, and it has high TC and stable piezoelectric properties, demonstrating that the (Sc,Ta,Ce) modified BTNO-based material is a wonderful candidate for high temperature applications.

  14. NASA-DoD Lead-Free Electronics Project

    NASA Technical Reports Server (NTRS)

    Kessel, Kurt

    2010-01-01

    This slide presentation reviews the current state of the lead-free electronics project. It characterizes the test articles, which were built with lead-free solder and lead-free component finishes. The tests performed and reported on are: thermal cycling, combine environments testing, mechanical shock testing, vibration testing and drop testing.

  15. Fundamental limitation to the magnitude of piezoelectric response of ⟨001⟩pc textured K0.5Na0.5NbO3 ceramic

    NASA Astrophysics Data System (ADS)

    Gupta, Shashaank; Belianinov, Alexei; Baris Okatan, Mahmut; Jesse, Stephen; Kalinin, Sergei V.; Priya, Shashank

    2014-04-01

    ⟨001⟩pc textured K0.5Na0.5NbO3 (KNN) ceramic was found to exhibit a 65% improvement in the longitudinal piezoelectric response as compared to its random counterpart. Piezoresponse force microscopy study revealed the existence of larger 180° and non-180° domains for textured ceramic as compared to the random ceramic. Improvement in piezoresponse by the development of ⟨001⟩pc texture is discussed in terms of the crystallographic nature of KNN and domain morphology. A comparative analysis performed with a rhombohedral composition suggested that the improvement in longitudinal piezoresponse of polycrystalline ceramics by the development of ⟨001⟩pc texture is determined by the crystal structure.

  16. Fundamental limitation to the magnitude of piezoelectric response of (001)pc textured K0.5Na0.5NbO3 ceramic

    SciTech Connect

    Gupta, Shashaank; Belianinov, Alex; Okatan, Mahmut B; Jesse, Stephen; Kalinin, Sergei V; Priya, Shashaank

    2014-01-01

    (001)pc textured K0.5Na0.5NbO3 (KNN) ceramic was found to exhibit a 65% improvement in the longitudinal piezoelectric response as compared to its random counterpart. Piezoresponse force microscopy study revealed the existence of larger 180 and non-180 domains for textured ceramic as compared to that of the random ceramic. Improvement in piezoresponse by the development of (001)pc texture is discussed in terms of the crystallographic nature of KNN and domain morphology. A comparative analysis performed with a rhombohedral composition suggested that the improvement in longitudinal piezoresponse of polycrystalline ceramics by the development of (001)pc texture is limited by the crystal structure.

  17. Properties of Cerium Containing Lead Free Solder

    NASA Astrophysics Data System (ADS)

    Xie, Huxiao

    With increasing concerns of the intrinsic toxicity of lead (Pb) in electronics, a series of tin (Sn) based alloys involving silver (Ag) and copper (Cu) have been proposed as replacements for Pb-Sn solder and widely accepted by industry. However, they have a higher melting point and often exhibit poorer damage tolerance than Pb-Sn alloys. Recently, a new class of alloys with trace amount of rare-earth (RE) elements has been discovered and investigated. In previous work from Prof. Chawla's group, it has been shown that cerium (Ce)-based Pb-free solder are less prone to oxidation and Sn whiskering, and exhibit desirable attributes of microstructural refinement and enhanced ductility relative to lanthanum (La)-based Sn-3.9Ag-0.7Cu (SAC) alloy. Although the formation of RESn3 was believed to be directly responsible for the enhanced ductility in RE-containing SAC solder by allowing microscopic voids to nucleate throughout the solder volume, this cavitation-based mechanism needs to be validated experimentally and numerically. Additionally, since the previous study has exhibited the realistic feasibility of Ce-based SAC lead-free solder alloy as a replacement to conventional SAC alloys, in this study, the proposed objective focuses on the in in-depth understanding of mechanism of enhanced ductility in Ce-based SAC alloy and possible issues associated with integration of this new class of solder into electronic industry, including: (a) study of long-term thermal and mechanical stability on industrial metallization, (b) examine the role of solder volume and wetting behavior of the new solder, relative to Sn-3.9Ag-0.7Cu alloys, (c) conduct experiments of new solder alloys in the form of mechanical shock and electromigration. The research of this new class alloys will be conducted in industrially relevant conditions, and the results would serve as the first step toward integration of these new, next generation solders into the industry.

  18. Synthesis and characterization of lead-free 0.5Ba(Zr{sub 0.2}Ti{sub 0.8})O{sub 3}-0.5(Ba{sub 0.7}Ca{sub 0.3})TiO{sub 3} ceramic

    SciTech Connect

    Coondoo, Indrani; Panwar, Neeraj; Kholkin, A. L.; Amorin, Harvey; Alguero, Miguel

    2013-06-07

    Polycrystalline sample of lead-free 0.5Ba(Zr{sub 0.2}Ti{sub 0.8})O{sub 3}-0.5(Ba{sub 0.7}Ca{sub 0.3})TiO{sub 3} ceramic has been synthesized by solid state reaction method. Single-phase perovskite structure with rhombohedral symmetry was confirmed by x-ray diffraction. Temperature dependent dielectric permittivity studies demonstrated frequency independent behavior, indicating that the studied sample was not a typical relaxor ferroelectric. A polymorphic phase transition between rhombohedral and tetragonal phase was noticed near room temperature followed by a tetragonal to cubic transition with 97 Degree-Sign C as the temperature of maximum permittivity. The macroscopic values of d{sub 33} and d{sub 31} were {approx}350 pC/N and -141 pm/V, whereas the electromechanical coupling factors k{sub p} and k{sub t} were 44.5% and 41.6%, respectively. Bulk P-E hysteresis loop was obtained with saturation polarization 11 {mu}C/cm{sup 2} and coercive field {approx}4 kV/cm. Distinct polarization contrast with a complex mosaic-like domain structure was observed in the out-of-plane mode of piezoresponse force microscopy. The domain width and the correlation length were estimated to be nearly 2 {mu}m and 827 nm, respectively. Local hysteresis loop with apparent coercive voltage, V{sub c} = 15.8 V, was observed.

  19. Processing of Piezoelectric (Li,Na,K)NbO3 Porous Ceramics and (Li,Na,K)NbO3/KNbO3 Composites

    NASA Astrophysics Data System (ADS)

    Kakimoto, Ken-ichi; Imura, Tomoya; Fukui, Yasuchika; Kuno, Masami; Yamagiwa, Katsuya; Mitsuoka, Takeshi; Ohbayashi, Kazushige

    2007-10-01

    Porous Li0.06(Na0.5K0.5)0.94NbO3 (LNKN-6) ceramics with different pore volumes have been prepared using preceramic powder and phenol resin fiber (KynolTM) as a pore former. It was confirmed that the porous ceramics synthesized by the “two-stage firing method” suppressed the loss of alkali elements from the porous body during heat treatment. The porous LNKN-6 ceramics were then converted to LNKN-6/KNbO3 composites through soaking and heat treatment using a sol-gel precursor source composed of KNbO3 to form 3-3-type composites. The microstructure, dielectric, and piezoelectric properties of the porous LNKN-6 ceramics and LNKN-6/KNbO3 composites were characterized and compared. The LNKN-6/KNbO3 composites had a hollow structure whose pores in the region near the surface were filled and coated with KNbO3 precipitates; however, a large amount of residual air was trapped in the pores inside the composites. As a result, the LNKN-6/KNbO3 composites fabricated using 30 vol % KynolTM showed an enhanced piezoelectric voltage output coefficient (g33) of 63.0× 10-3 V\\cdotm/N, compared with monolithic LNKN-6 ceramics having a g33 of 30.2× 10-3 V\\cdotm/N.

  20. Domain structures and local switching in lead-free piezoceramics Ba0.85Ca0.15Ti0.90Zr0.10O3

    NASA Astrophysics Data System (ADS)

    Turygin, A. P.; Neradovskiy, M. M.; Naumova, N. A.; Zayats, D. V.; Coondoo, I.; Kholkin, A. L.; Shur, V. Ya.

    2015-08-01

    Lead-free piezoelectrics are becoming increasingly important in view of environmental problems of currently used lead-based perovskites such as lead zirconate titanate (PZT). One of the recent candidates for PZT replacement, solid solutions of BaZr0.2Ti0.8O3 and Ba0.7Ca0.3TiO3, are investigated in this work by piezoresponse force microscopy. Coexistence of the tetragonal and rhombohedral phases in this material is observed, which probably gives rise to easy polarization switching due to multiple domain states. The period of observed domain lamella scales with the grain size obeying well-known square root dependence characteristic of BaTiO3 ceramics. Domain switching and relaxation are investigated at the nanoscale as a function of the applied voltage and duration of the applied voltage pulses. The observed distortion of piezoresponse hysteresis loops near grain boundaries is attested to the increased concentration of defects. Nanoscale piezoelectric properties of these materials are discussed.

  1. Piezoelectric MEMS for energy harvesting

    NASA Astrophysics Data System (ADS)

    Kanno, Isaku

    2015-12-01

    Recently, piezoelectric MEMS have been intensively investigated to create new functional microdevices, and some of them have already been commercialized such as MEMS gyrosensors or miropumps of inkjet printer head. Piezoelectric energy harvesting is considered to be one of the promising future applications of piezoelectric MEMS. In this report, we introduce the deposition of the piezoelectric PZT thin films as well as lead-free KNN thin films. We fabricated piezoelectric energy harvesters of PZT and KNN thin films deposited on stainless steel cantilevers and compared their power generation performance.

  2. Piezoelectric and dielectric properties of Sn-doped (Na0.5K0.5)NbO3 ceramics processed under low oxygen partial pressure atmosphere

    NASA Astrophysics Data System (ADS)

    Kobayashi, Keisuke; Doshida, Yutaka; Mizuno, Youichi; Randall, Clive A.

    2014-01-01

    Sn-doped (Na0.5K0.5)NbO3 (Sn-NKN) ceramics fired under various oxygen partial pressure (pO2) conditions have been investigated and discussed in terms of bulk piezoelectric and dielectric properties. X-ray diffraction measurements and Rayleigh analysis indicate that the substitution site of the Sn cations depend on the pO2 atmosphere in the firing process. For pO2 higher than 1.0 × 10-10 atm, Sn cations mainly substitute as Sn4+ at the B-site of perovskite NKN, whereas Sn2+ A-site substitution is favored under a low-pO2 atmosphere. Low-pO2 fired Sn-NKN ceramics exhibit higher relative permittivity, Curie temperature, and piezoelectric coefficient (d33). Sn2+ at A-site acts as a donor and reduces the p-type carrier concentrations that result from an electronic compensation of metal vacancies created through the high volatility of Na and K suboxides. The higher piezoelectricity and resistivity in low-pO2 fired Sn-NKN ceramics make this material suitable for base-metal cofired devices such as Ni-inner-electrode multilayer capacitors and actuators.

  3. Robust polarization and strain behavior of Sm-modified BiFeO3 piezoelectric ceramics.

    PubMed

    Walker, Julian; Budic, Bojan; Bryant, Peter; Kurusingal, Valsala; Sorrell, Charles C; Bencan, Andreja; Rojac, Tadej; Valanoor, Nagarajan

    2015-01-01

    The route to phase-pure BiFeO3 (BFO) ceramics with excellent ferroelectric and electromechanical properties is severely impeded by difficulties associated with the perovskite phase stability during synthesis. This has meant that dopants and solid solutions with BFO have been investigated as a means of not only improving the functional properties, but also of improving the perovskite phase formation of BFO-based ceramics. The present work focuses on Sm-modified BFO ceramics of composition Bi0.88Sm0.12FeO3. The polarization and strain behaviors were investigated as a function of the phase composition, microstructure, and chemical composition. Addition of Sm reduces the susceptibility of the BFO perovskite to phase degradation by Si impurities. Si was observed to react into Sm-rich grains dispersed within the microstructure, with no large increases in the amount of bismuth-parasitic phases, namely Bi25FeO39 and Bi2Fe4O9. These as-prepared ceramics exhibited robust polarization behavior showing maximum remnant polarizations of ~40 to 50 μC/cm(2). The electric-fieldinduced strain showed an appreciable stability in terms of the driving field frequency with maximum peak-to-peak strains of ~0.3% and a coercive field of ~130 kV/cm. PMID:25585392

  4. Enhanced piezoelectric performance of (0.98-x)Bi(Sc{sub 3/4}In{sub 1/4})O{sub 3}-xPbTiO{sub 3}-0.02Pb(Zn{sub 1/3}Nb{sub 2/3})O{sub 3} ternary high temperature piezoelectric ceramics

    SciTech Connect

    Chen Jianguo; Zhao Tianlong; Cheng Jinrong; Dong Shuxiang

    2013-04-14

    (0.98-x)Bi(Sc{sub 3/4}In{sub 1/4})O{sub 3}-xPbTiO{sub 3}-0.02Pb(Zn{sub 1/3}Nb{sub 2/3})O{sub 3} (BSI-PT-PZN) high temperature piezoelectric ceramics were prepared by traditional solid-state reaction method. Combining X-ray diffraction results with piezoelectric data, it was found that the morphotropic phase boundary (MPB) occurred at x = 0.575. The piezoelectric constant d{sub 33}, curie temperature T{sub c}, and electromechanical coupling factor k{sub p} of BIS-PT-PZN ceramics with MPB composition were 427 pC/N, 412 Degree-Sign C, and 0.51, respectively. Furthermore, the strain of BIS-PT-PZN ceramics reached up to 0.25% under the electric field of 40 kV/cm. Temperature-dependent electromechanical coupling coefficient for MPB composition was stable from room temperature up to 350 Degree-Sign C. The piezoelectric properties of BIS-PT-PZN ceramics were comparable to that of 0.36BiScO{sub 3}-0.64PbTiO{sub 3} (BS-PT) ceramics, and the piezoelectric constant d{sub 33} of BIS-PT-PZN ceramics was about twice that of our previous reported 0.4Bi(Sc{sub 3/4}In{sub 1/4})O{sub 3}-0.6PbTiO{sub 3} (BSI-PT) ceramics. The reduction in the expensive Sc{sub 2}O{sub 3} content and comparable piezoelectric properties with BS-PT ceramics indicated that BIS-PT-PZN ceramics were promising for commercial applications as high temperature actuators and sensors.

  5. Enhanced piezoelectric performance of (0.98-x)Bi(Sc3/4In1/4)O3-xPbTiO3-0.02Pb(Zn1/3Nb2/3)O3 ternary high temperature piezoelectric ceramics

    NASA Astrophysics Data System (ADS)

    Chen, Jianguo; Zhao, Tianlong; Cheng, Jinrong; Dong, Shuxiang

    2013-04-01

    (0.98-x)Bi(Sc3/4In1/4)O3-xPbTiO3-0.02Pb(Zn1/3Nb2/3)O3 (BSI-PT-PZN) high temperature piezoelectric ceramics were prepared by traditional solid-state reaction method. Combining X-ray diffraction results with piezoelectric data, it was found that the morphotropic phase boundary (MPB) occurred at x = 0.575. The piezoelectric constant d33, curie temperature Tc, and electromechanical coupling factor kp of BIS-PT-PZN ceramics with MPB composition were 427 pC/N, 412 °C, and 0.51, respectively. Furthermore, the strain of BIS-PT-PZN ceramics reached up to 0.25% under the electric field of 40 kV/cm. Temperature-dependent electromechanical coupling coefficient for MPB composition was stable from room temperature up to 350 °C. The piezoelectric properties of BIS-PT-PZN ceramics were comparable to that of 0.36BiScO3-0.64PbTiO3 (BS-PT) ceramics, and the piezoelectric constant d33 of BIS-PT-PZN ceramics was about twice that of our previous reported 0.4Bi(Sc3/4In1/4)O3-0.6PbTiO3 (BSI-PT) ceramics. The reduction in the expensive Sc2O3 content and comparable piezoelectric properties with BS-PT ceramics indicated that BIS-PT-PZN ceramics were promising for commercial applications as high temperature actuators and sensors.

  6. Bright upconversion luminescence and increased Tc in CaBi{sub 2}Ta{sub 2}O{sub 9}:Er high temperature piezoelectric ceramics

    SciTech Connect

    Peng Dengfeng; Wang Xusheng; Yao Xi; Xu Chaonan; Lin Jian; Sun Tiantuo

    2012-05-15

    Er{sup 3+} doped CaBi{sub 2}Ta{sub 2}O{sub 9} (CBT) bismuth layered-structure high temperature piezoelectric ceramics were synthesized by the traditional solid state method. The upconversion (UC) emission properties of Er{sup 3+} doped CBT ceramics were investigated as a function of Er{sup 3+} concentration and incident pump power. A bright green upconverted emission was obtained under excitation 980 nm at room temperature. The observed strong green and weak red emission bands corresponded to the transitions from {sup 4}S{sub 3/2} and {sup 4}F{sub 9/2} to {sup 4}I{sub 15/2}, respectively. The dependence of UC emission intensity on pumping power indicated that a three-photon process was involved in UC emissions. Studies of dielectric with temperature have also been carried out. Introduction of Er increased the Curie temperature of CBT, thus, making this ceramic suitable for sensor applications at higher temperatures. Because of its strong up-converted emission and increased Tc, the multifunctional high temperature piezoelectric ceramic may be useful in high temperature sensor, fluorescence thermometry, and optical-electro integration applications.

  7. Effect of orthorhombic distortion on dielectric and piezoelectric properties of CaBi{sub 4}Ti{sub 4}O{sub 15} ceramics

    SciTech Connect

    Tanwar, Amit; Sreenivas, K.; Gupta, Vinay

    2009-04-15

    High temperature bismuth layered piezoelectric and ferroelectric ceramics of CaBi{sub 4}Ti{sub 4}O{sub 15} (CBT) have been prepared using the solid state route. The formation of single phase material with orthorhombic structure was verified from x-ray diffraction and Raman spectroscopy. The orthorhombic distortion present in the CBT ceramic sintered at 1200 deg. C was found to be maximum. A sharp phase transition from ferroelectric to paraelectric was observed in the temperature dependent dielectric studies of all CBT ceramics. The Curie's temperature (T{sub c}=790 deg. C) was found to be independent of measured frequency. The behavior of ac conductivity as a function of frequency (100 Hz-1 MHz) at low temperatures (<500 deg. C) follows the power law and is attributed to hopping conduction. The presence of large orthorhombic distortion in the CBT ceramic sintered at 1200 deg. C results in high dielectric constant, low dielectric loss, and high piezoelectric coefficient (d{sub 33}). The observed results indicate the important role of orthorhombic distortion in determining the improved property of multicomponent ferroelectric material.

  8. Effects of porosity on dielectric and piezoelectric properties of porous lead zirconate titanate ceramics

    SciTech Connect

    Yang Ankun; Wang Changan; Guo Rui; Huang Yong

    2011-04-11

    We report porous lead zirconate titanate ceramics fabricated by tert-butyl alcohol-based gel-casting process which show a very high thickness electromechanical coupling coefficient (0.77), high hydrostatic figure of merit (9594x10{sup -15} m{sup 2}/N), and low acoustic impedance (3.7 Mrayls). We show that the porosity effectively affects the performance of the samples in two ways: (1) a higher porosity simplifies the resonance behavior, leading to more efficient energy transduction; (2) its replacement of active ceramic phase leads to low relative permittivity, high hydrostatic figure of merit, and low acoustic impedance. It was confirmed the properties could be tailored by controlling the porosity.

  9. Influence of a silver epoxy dopant on the performance of broken piezoelectric ceramic transducer based on an analytical model

    NASA Astrophysics Data System (ADS)

    Abdulhamed Mohammed, Arshed; Haris, Sallehuddin Mohamed; Zaki Nuawi, Mohd

    2014-04-01

    Over the past decade, an unprecedented increase in the types of, the methods of using, and the demand for piezoelectric ceramic transducers (PCTs) has been observed in the market. These factors increase the probability of PCTs being subjected to breakage. Therefore, this study proposes a simple, low-cost procedure which uses available components to repair and reinstall five broken PCTs and then tests them as emitters and receivers in bulk and surface wave detection. An SM211 PCT with a 7.2 MHz frequency, a high damping and electromechanical coupling coefficient, and two silver electrodes were selected for the experiment. A Mason circuit was used for the procedure, the Laplace transform was used as a mathematical analysis method, and MATLAB was the technical computing language used to model the new transfer function for this type of PCT. This study proved that silver electrodes are a significant load on PCTs, particularly at high frequencies. Very good identity correlations between this mathematical and the experimental responses of the standard PCT were obtained. Later this mathematical model was used to prove the explanations provided by this research. The response of the standard PCT was compared with that of the samples of PCT that have been repaired (SPCTR). Through this comparison, many conclusions were obtained, and several recommendations were made, which can be taken advantage of by people who are interested in this field of research. Such recommendations include analyzing the response of SPCTR and explaining the types of ultrasonic tests in which SPCTR can be used.

  10. Effect of SHI irradiation on NBT-BT ceramics: Transformation of relaxor ferroelectric to ferroelectric nature

    NASA Astrophysics Data System (ADS)

    Shanmuga Sundari, S.; Kumar, Binay; Asokan, K.; Dhanasekaran, R.

    2013-01-01

    The lead free NBT-BT ceramics prepared by conventional solid state reaction method were irradiated with 120 MeV Au9+ ions with different fluences. The structural, dielectric and piezoelectric studies were carried out before and after irradiation. The agglomeration and increase of grain size are observed in SEM analysis after the irradiation. The diffuse phase transition disappeared after high fluence of irradiation and the material becomes ferroelectric in nature. The piezoelectric properties were decreased due to the reduced stability of the ferroelectric domains after the irradiation.

  11. Enhanced piezoelectric properties of lead zirconate titanate sol-gel derived ceramics using single crystal PbZr0.52Ti0.48O3 cubes

    NASA Astrophysics Data System (ADS)

    Lin, Yirong; Andrews, Clark; Sodano, Henry A.

    2010-09-01

    Piezoceramic materials have attracted much attention for sensing, actuation, structural health monitoring, and energy harvesting applications in the past two decades due to their excellent coupling between energy in the mechanical and electrical domains. Among all piezoceramic materials, lead zirconate titanate (PZT) has been the most broadly studied and implemented, in industrial applications due to its high piezoelectric coupling coefficients. Piezoceramic materials are most often employed as thin films or monolithic wafers. While there are numerous methods for the synthesis of PZT films, the sol-gel processing technique is the most widely used due to its low densification temperature, the ease at which the film can be applied without costly physical deposition equipment and the capability to fabricate both thin and thick films. However, the piezoelectric properties of PZT sol-gel derived films are substantially lower than those of bulk materials, which limit the application of sol-gel films. In comparison, single crystal PZT materials have higher piezoelectric coupling coefficients than polycrystalline materials due to their uniform dipole alignment. This paper will introduce a novel technique to enhance the piezoelectric properties of PZT sol-gel derived ceramics through the use of single crystal PbZr0.52Ti0.48O3 microcubes as an inclusion in the PZT sol-gel. The PZT single crystal cubes are synthesized through a hydrothermal based method and their geometry and crystal structure is characterized through scanning electron microscopy (SEM) and x-ray diffraction (XRD). A mixture of PZT cubes and sol-gel will then be sintered to crystallize the sol-gel and obtain full density of the ceramic. XRD and SEM analysis of the cross section of the final ceramics will be performed and compared to show the crystal structure and microstructure of the samples. The P-E properties of the samples will be tested using a Sawyer-Tower circuit. Finally, a laser interferometer will be used to directly measure the piezoelectric strain-coupling coefficient of the PZT sol-gel ceramics with and without PZT cube inclusions. The results will show that with the integration of PZT crystal inclusions the d33 coupling coefficient will increase more than 200% compared to that of pure PbZr0.52Ti0.48O3 sol-gel.

  12. NASA-DoD Lead-Free Electronics Project

    NASA Technical Reports Server (NTRS)

    Kessel, Kurt

    2007-01-01

    The primary technical objective of the project is to undertake comprehensive testing to generate information on failure modes/criteria to better understand the reliability of: Packages (e.g., TSOP, BGA, PDIP) assembled and reworked with lead-free alloys Packages (e.g., TSOP, BGA, PDIP) assembled and reworked with mixed (lead/lead-free) alloys.

  13. NASA-DoD Lead-Free Electronics Project

    NASA Technical Reports Server (NTRS)

    Kessel, Kurt R.

    2009-01-01

    In response to concerns about risks from lead-free induced faults to high reliability products, NASA has initiated a multi-year project to provide manufacturers and users with data to clarify the risks of lead-free materials in their products. The project will also be of interest to component manufacturers supplying to high reliability markets. The project was launched in November 2006. The primary technical objective of the project is to undertake comprehensive testing to generate information on failure modes/criteria to better understand the reliability of: - Packages (e.g., TSOP, BGA, PDIP) assembled and reworked with solder interconnects consisting of lead-free alloys - Packages (e.g., TSOP, BGA, PDIP) assembled and reworked with solder interconnects consisting of mixed alloys, lead component finish/lead-free solder and lead-free component finish/SnPb solder.

  14. NASA-DoD Lead-Free Electronics Project

    NASA Technical Reports Server (NTRS)

    Kessel, Kurt R.

    2009-01-01

    In response to concerns about risks from lead-free induced faults to high reliability products, NASA has initiated a multi-year project to provide manufacturers and users with data to clarify the risks of lead-free materials in their products. The project will also be of interest to component manufacturers supplying to high reliability markets. The project was launched in November 2006. The primary technical objective of the project is to undertake comprehensive testing to generate information on failure modes/criteria to better understand the reliability of: - Packages (e.g., TSOP, BOA, PDIP) assembled and reworked with solder interconnects consisting of lead-free alloys - Packages (e.g., TSOP, BOA, PDIP) assembled and reworked with solder interconnects consisting of mixed alloys, lead component finish/lead-free solder and lead-free component finish/SnPb solder.

  15. NASA-DoD Lead-Free Electronics Project

    NASA Technical Reports Server (NTRS)

    Kessel, Kurt

    2009-01-01

    In response to concerns about risks from lead-free induced faults to high reliability products, NASA has initiated a multi-year project to provide manufacturers and users with data to clarify the risks of lead-free materials in their products. The project will also be of interest to component manufacturers supplying to high reliability markets. The project was launched in November 2006. The primary technical objective of the project is to undertake comprehensive testing to generate information on failure modes/criteria to better understand the reliability of: (1) Packages (e.g., Thin Small Outline Package [TSOP], Ball Grid Array [BGA], Plastic Dual In-line Package [PDIP]) assembled and reworked with solder interconnects consisting of lead-free alloys (2) Packages (e.g., TSOP, BGA, PDIP) assembled and reworked with solder interconnects consisting of mixed alloys, lead component finish/lead-free solder and lead-free component finish/SnPb solder

  16. Wireless energy transmission through a sealed wall using the acoustic-electric interaction of piezoelectric ceramics

    NASA Astrophysics Data System (ADS)

    Hu, Hongping; Xue, Huan; Hu, Yuantai; Chen, Xuedong

    2009-07-01

    We propose a system to transmit and store electric energy by using transmitting element, a chargeable battery, and a rectifier together with a dc-dc converter to connect the two components as an integrated system. The transmitting element is modeled by two piezoelectric transducers. One is as the driving transducer for generating acoustic wave; the other is as the receiving transducer for converting the acoustic energy into electric energy. A dc-dc converter employed in the storage circuit is to match the optimal output voltage of the receiving transducer with the battery voltage for efficient charging. A synchronized switch harvesting on inductor (SSHI) in parallel with the receiving transducer is introduced to artificially extend the closed circuit interval of the rectifier. This analysis extends a previous one by considering that influence of wall thickness which always exists in the application. The characteristics of the energy-transmitting element are studied. Performance of the energy-transmitting element is optimized by synthetic adjusting parameters of the element, and carefully choosing input frequency of electric source.

  17. Lead-free KNbO3 ferroelectric nanorod based flexible nanogenerators and capacitors

    NASA Astrophysics Data System (ADS)

    Jung, Jong Hoon; Chen, Chih-Yen; Yun, Byung Kil; Lee, Nuri; Zhou, Yusheng; Jo, William; Chou, Li-Jen; Wang, Zhong Lin

    2012-09-01

    In spite of high piezoelectricity, only a few one-dimensional ferroelectric nano-materials with perovskite structure have been used for piezoelectric nanogenerator applications. In this paper, we report high output electrical signals, i.e. an open-circuit voltage of 3.2 V and a closed-circuit current of 67.5 nA (current density 9.3 nA cm-2) at 0.38% strain and 15.2% s-1 strain rate, using randomly aligned lead-free KNbO3 ferroelectric nanorods (˜1 μm length) with piezoelectric coefficient (d33 ˜ 55 pm V -1). A flexible piezoelectric nanogenerator is mainly composed of KNbO3-poly(dimethylsiloxane) (PDMS) composite sandwiched by Au/Cr-coated polymer substrates. We deposit a thin poly(methyl methacrylate) (PMMA) layer between the KNbO3-PDMS composite and the Au/Cr electrode to completely prevent dielectric breakdown during electrical poling and to significantly reduce leakage current during excessive straining. The flexible KNbO3-PDMS composite device shows a nearly frequency-independent dielectric constant (˜3.2) and low dielectric loss (<0.006) for the frequency range of 102-105 Hz. These results imply that short and randomly aligned ferroelectric nanorods can be used for a flexible high output nanogenerator as well as high-k capacitor applications by performing electrical poling and further optimizing the device structure.

  18. Analysis of Lead-Free Piezoceramic-Based Power Ultrasonic Transducers for Wire Bonding.

    PubMed

    Mathieson, Andrew; DeAngelis, Dominick A

    2016-01-01

    Since the 1950s, lead zirconate-titanate (PZT) has been the dominant transduction material utilized in power ultrasonics, while lead-free piezoceramics have been largely neglected due to their relatively poor piezoelectric and electromechanical properties. However, the implementation of environmental directives that regulate and control the use of hazardous materials, such as lead, triggered a search for new high-performance lead-free piezoceramics. Recent advances have led to lead-free piezoceramics exhibiting properties similar to PZT, but despite this, reports utilizing these novel piezoceramics in practice are limited. This research employs a modified variant of bismuth sodium titanate (BNT) in a power ultrasonic transducer used for metal welding during the manufacture of semiconductors. The important factors for transducer reliability and performance are investigated, such as piezoceramic aging and stack preload level. It is reported that BNT-based transducers exhibit good stability, and can withstand a stack preload level of 90 MPa without depoling. Although the BNT-based transducers exhibited larger dissipative losses compared to identical PZT8-based transducers, the tool displacement gain was larger under constant current conditions. Semiconductor wire bonds which satisfied the commercial quality control requirements were also formed by this BNT-based transducer. PMID:26584490

  19. Production of continuous piezoelectric ceramic fibers for smart materials and active control devices

    NASA Astrophysics Data System (ADS)

    French, Jonathan D.; Weitz, Gregory E.; Luke, John E.; Cass, Richard B.; Jadidian, Bahram; Bhargava, Parag; Safari, Ahmad

    1997-05-01

    Advanced Cerametrics Inc. has conceived of and developed the Viscous-Suspension-Spinning Process (VSSP) to produce continuous fine filaments of nearly any powdered ceramic materials. VSSP lead zirconate titanate (PZT) fiber tows with 100 and 790 filaments have been spun in continuous lengths exceeding 1700 meters. Sintered PZT filaments typically are 10 - 25 microns in diameter and have moderate flexibility. Prior to carrier burnout and sintering, VSSP PZT fibers can be formed into 2D and 3D shapes using conventional textile and composite forming processes. While the extension of PZT is on the order of 20 microns per linear inch, a woven, wound or braided structure can contain very long lengths of PZT fiber and generate comparatively large output strokes from relatively small volumes. These structures are intended for applications such as bipolar actuators for fiber optic assembly and repair, vibration and noise damping for aircraft, rotorcraft, automobiles and home applications, vibration generators and ultrasonic transducers for medical and industrial imaging. Fiber and component cost savings over current technologies, such as the `dice-and-fill' method for transducer production, and the range of unique structures possible with continuous VSSP PZT fiber are discussed. Recent results have yielded 1-3 type composites (25 vol% PZT) with d33 equals 340 pC/N, K equals 470, and g33 equals 80 mV/N, kt equals 0.54, kp equals 0.19, dh equals 50.1pC/N and gh equals 13 mV/N.

  20. Modeling of material properties of piezoelectric ceramics taking into account damage development under static compression

    NASA Astrophysics Data System (ADS)

    Mizuno, M.; Nishikata, T.; Okayasu, M.

    2013-10-01

    We have carried out static compression tests in the poling direction for PZT ceramics and evaluated the material properties by measuring the resonance and anti-resonance frequencies and electrostatic capacity at regular intervals. Then the variation in the material properties up to fracture was clarified. Also, the development of internal damage was also clarified quantitatively by evaluating a damage variable on the basis of the continuum damage mechanics. The damage variable was calculated from the ratio of the elastic coefficient to its initial value. In the present paper, the development of internal damage was formulated as an evolution equation of the damage variable. In the formulation, a threshold stress leading to the onset of damage was considered. Moreover, the variation in material properties was related to the damage variable and formulated as material functions of the damage variable. The development of internal damage and the variation in material properties were simulated by the equations proposed in the present paper and the validity of the equations was verified by comparing the predictions with experimental results.

  1. An integrated microfluidic chip with 40 MHz lead-free transducer for fluid analysis

    SciTech Connect

    Lee, S. T. F.; Lam, K. H.; Lei, L.; Zhang, X. M.; Chan, H. L. W.

    2011-02-15

    The design, fabrication, and evaluation of a high-frequency transducer made from lead-free piezoceramic for the application of microfluidic analysis is described. Barium strontium zirconate titanate [(Ba{sub 0.95}Sr{sub 0.05})(Zr{sub 0.05}Ti{sub 0.95})O{sub 3}, abbreviated as BSZT] ceramic has been chosen to be the active element of the transducer. The center frequency and bandwidth of this high-frequency ultrasound transducer have been measured to be 43 MHz and 56.1%, respectively. The transducer was integrated into a microfluidic channel and used to measure the sound velocity and attenuation of the liquid flowing in the channel. Results suggest that lead-free high-frequency transducers could be used for in situ analysis of property of the fluid flowing through the microfluidic system.

  2. An integrated microfluidic chip with 40 MHz lead-free transducer for fluid analysis.

    PubMed

    Lee, S T F; Lam, K H; Lei, L; Zhang, X M; Chan, H L W

    2011-02-01

    The design, fabrication, and evaluation of a high-frequency transducer made from lead-free piezoceramic for the application of microfluidic analysis is described. Barium strontium zirconate titanate [(Ba(0.95)Sr(0.05))(Zr(0.05)Ti(0.95))O(3), abbreviated as BSZT] ceramic has been chosen to be the active element of the transducer. The center frequency and bandwidth of this high-frequency ultrasound transducer have been measured to be 43 MHz and 56.1%, respectively. The transducer was integrated into a microfluidic channel and used to measure the sound velocity and attenuation of the liquid flowing in the channel. Results suggest that lead-free high-frequency transducers could be used for in situ analysis of property of the fluid flowing through the microfluidic system. PMID:21361626

  3. Domain wall motion effect on the anelastic behavior in lead zirconate titanate piezoelectric ceramics

    NASA Astrophysics Data System (ADS)

    Bourim, El Mostafa; Tanaka, Hidehiko; Gabbay, Maurice; Fantozzi, Gilbert; Cheng, Bo Lin

    2002-05-01

    Three undoped lead zirconate titanate (PZT) ceramics were prepared with compositions close to the morphotropic phase boundary: Pb(Zr0.50Ti0.50)O3, Pb(Zr0.52Ti0.48)O3, and Pb(Zr0.54Ti0.46)O3. Internal friction Q-1 and shear modulus G were measured versus temperature from 20 °C to 500 °C. Experiments were performed on an inverted torsional pendulum at low frequencies (0.1, 0.3, and 1 Hz). The ferroelectric-paraelectric phase transition results in a peak (P1) of Q-1 correlated with a sharp minimum M1 of G. Moreover the Q-1(T) curves show two relaxation peaks called R1 and R2 respectively, correlated with two shear modulus anomalies called A1 and A2 on the G(T) curves. The main features of the transition P1 peak are studied, they suggest that its behavior is similar to the internal friction peaks associated with martensitic transformation. The relaxation peak, R1 and R2 are both attributed to motion of domain walls (DWs), and can be analyzed by thermal activated process described by Arrhenius law. The R2 peak is demonstrated to be due to the interaction of domain walls and oxygen vacancies because it depends on oxygen vacancy concentration and electrical polarization. However, the R1 peak is more complex; its height is found to be increased as stress amplitude and heating rate increase. It seems that the R1 peak is influenced by three mechanisms: (i) relaxation due to DW-point defects interaction, (ii) variation of domain wall density, and (iii) domain wall depinning from point defect clusters.

  4. Enhanced piezoelectricity and high temperature poling effect in (1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 ceramics via an ethylene glycol route

    NASA Astrophysics Data System (ADS)

    Tailor, H. N.; Ye, Z.-G.

    2010-05-01

    A solution chemical method utilizing ethylene glycol as solvent has been developed to prepare the ceramics of (1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3[(1-x)PMN-xPT] from a precursor powder that can be pressed and fired in one step to produce high quality ceramics with excellent piezoelectric properties. The ceramics reach a relative density of up to 97% of the theoretical value after direct calcinations. This high density is achieved without the need of additional sintering after calcination which is usually required in conventional solid state syntheses to produce ceramics. The ceramics exhibit a unipolar piezoelectric coefficient d33 of 848 pC/N, which is one of the highest values for any unmodified/untextured binary systems reported to date. Since the piezoelectric properties depend on composition and electric field, the effect of poling conditions was investigated. A critical temperature limit has been found, above which poling can dramatically impair the piezoelectric properties due to a field-induced increase in the monoclinic phase component around the morphotropic phase boundary.

  5. Enhanced piezoelectricity and high temperature poling effect in (1-x)Pb(Mg{sub 1/3}Nb{sub 2/3})O{sub 3}-xPbTiO{sub 3} ceramics via an ethylene glycol route

    SciTech Connect

    Tailor, H. N.; Ye, Z.-G.

    2010-05-15

    A solution chemical method utilizing ethylene glycol as solvent has been developed to prepare the ceramics of (1-x)Pb(Mg{sub 1/3}Nb{sub 2/3})O{sub 3}-xPbTiO{sub 3}[(1-x)PMN-xPT] from a precursor powder that can be pressed and fired in one step to produce high quality ceramics with excellent piezoelectric properties. The ceramics reach a relative density of up to 97% of the theoretical value after direct calcinations. This high density is achieved without the need of additional sintering after calcination which is usually required in conventional solid state syntheses to produce ceramics. The ceramics exhibit a unipolar piezoelectric coefficient d{sub 33} of 848 pC/N, which is one of the highest values for any unmodified/untextured binary systems reported to date. Since the piezoelectric properties depend on composition and electric field, the effect of poling conditions was investigated. A critical temperature limit has been found, above which poling can dramatically impair the piezoelectric properties due to a field-induced increase in the monoclinic phase component around the morphotropic phase boundary.

  6. NASA-DoD Lead-Free Electronics Project

    NASA Technical Reports Server (NTRS)

    Kessel, Kurt R.

    2009-01-01

    The primary technical objective of this project is to undertake comprehensive testing to generate information on failure modes/criteria to better understand the reliability of: (1) Packages (e.g., Thin Small Outline Package [TSOP], Ball Grid Array [BGA], Plastic Dual In-line Package [PDIP]) assembled and reworked with lead-free alloys, (2) Packages (e.g., TSOP, BGA, PDIP) assembled and reworked with mixed (lead/lead-free) alloys.

  7. NASA-DoD Lead-Free Electronics Project

    NASA Technical Reports Server (NTRS)

    Kessel, Kurt

    2010-01-01

    Original Equipment Manufacturers (OEMs), depots, and support contract ors have to be prepared to deal with an electronics supply chain that increasingly provides parts with lead-free finishes, some labeled no differently and intermingled with their SnPb counterparts. Allowance of lead-free components presents one of the greatest risks to the r eliability of military and aerospace electronics. The introduction of components with lead-free terminations, termination finishes, or cir cuit boards presents a host of concerns to customers, suppliers, and maintainers of aerospace and military electronic systems such as: 1. Electrical shorting due to tin whiskers 2. Incompatibility of lead-f ree processes and parameters (including higher melting points of lead -free alloys) with other materials in the system 3. Unknown material properties and incompatibilities that could reduce solder joint reli ability As the transition to lead-free becomes a certain reality for military and aerospace applications, it will be critical to fully un derstand the implications of reworking lead-free assemblies.

  8. Effect of texturing on polarization switching dynamics in ferroelectric ceramics

    NASA Astrophysics Data System (ADS)

    Zhukov, Sergey; Genenko, Yuri A.; Koruza, Jurij; Schulthei, Jan; von Seggern, Heinz; Sakamoto, Wataru; Ichikawa, Hiroki; Murata, Tatsuro; Hayashi, Koichiro; Yogo, Toshinobu

    2016-01-01

    Highly (100),(001)-oriented (Ba0.85Ca0.15)TiO3 (BCT) lead-free piezoelectric ceramics were fabricated by the reactive templated grain growth method using a mixture of plate-like CaTiO3 and BaTiO3 particles. Piezoelectric properties of the ceramics with a high degree of texture were found to be considerably enhanced compared with the BCT ceramics with a low degree of texture. With increasing the Lotgering factor from 26% up to 94%, the piezoelectric properties develop towards the properties of a single crystal. The dynamics of polarization switching was studied over a broad time domain of 8 orders of magnitude and was found to strongly depend on the degree of orientation of the ceramics. Samples with a high degree of texture exhibited 2-3 orders of magnitude faster polarization switching, as compared with the ones with a low degree of texture. This was rationalized by means of the Inhomogeneous Field Mechanism model as a result of the narrower statistical distribution of the local electric field values in textured media, which promotes a more coherent switching process. The extracted microscopic parameters of switching revealed a decrease of the critical nucleus energy in systems with a high degree of texture providing more favorable switching conditions related to the enhanced ferroelectric properties of the textured material.

  9. NASA-DoD Lead-Free Electronics Project

    NASA Technical Reports Server (NTRS)

    Kessel, Kurt

    2011-01-01

    Original Equipment Manufacturers (OEMs). depots. and support contractors have to be prepared to deal with an electronics supply chain thaI increasingly provides parts with lead-free finishes. some labeled no differently and intenningled with their SnPb counterparts. Allowance oflead-free components presents one of the greatest risks to the reliability of military and aerospace electronics. The introduction of components with lead-free lenninations, tennination finishes, or circuit boards presents a host of concerns to customers. suppliers, and maintainers of aerospace and military electronic systems such as: 1. Electrical shorting due to tin whiskers; 2. Incompatibility oflead-free processes and parameters (including higher melting points of lead-free alloys) with other materials in the system; and 3. Unknown material properties and incompatibilities that could reduce solder joint re liability.

  10. Anomalous Skin Effect in the Lead-Free Relaxor NBT

    NASA Astrophysics Data System (ADS)

    Gehring, Peter; Ge, Wenwei; Phelan, Daniel; Zhang, Qinhui; Li, Jie Fang; Viehland, Dwight; Luo, Hasuo; Boatner, Lynn

    2014-03-01

    Several x-ray and neutron powder diffraction studies have shown that the room-temperature space group of the lead-free relaxor NBT is monoclinic Cc and not rhombohedral R3c, as was previously believed. Motivated by these findings, we performed room-temperature neutron scattering measurements on a large (3.5 gram) single crystal of the lead-free relaxor NBT. Our data confirm the R3c symmetry for bulk NBT and place a strict bound on the strength of the 1/2(111) superlattice reflection associated with the Cc space group based on the published atomic coordinates. We show that a skin effect, analogous to that reported in the relaxors PZN and PMN-10%PT, can reconcile our single-crystal data with these other studied. We believe this represents the first evidence of the relaxor skin effect in a lead-free relaxor.

  11. Piezoelectric materials used in underwater acoustic transducers

    SciTech Connect

    Li, Huidong; Deng, Zhiqun; Carlson, Thomas J.

    2012-07-07

    Piezoelectric materials have been used in underwater acoustic transducers for nearly a century. In this paper, we reviewed four different types of piezoelectric materials: piezoelectric ceramics, single crystals, composites, and polymers, which are widely used in underwater acoustic transducers nowadays. Piezoelectric ceramics are the most dominant material type and are used as a single-phase material or one of the end members in composites. Piezoelectric single crystals offer outstanding electromechanical response but are limited by their manufacturing cost. Piezoelectric polymers provide excellent acoustic impedance matching and transducer fabrication flexibility although their piezoelectric properties are not as good as ceramics and single crystals. Composites combined the merits of ceramics and polymers and are receiving increased attention. The typical structure and electromechanical properties of each type of materials are introduced and discussed with respect to underwater acoustic transducer applications. Their advantages and disadvantages are summarized. Some of the critical design considerations when developing underwater acoustic transducers with these materials are also touched upon.

  12. Effects of sintering aid CuTa{sub 2}O{sub 6} on piezoelectric and dielectric properties of sodium potassium niobate ceramics

    SciTech Connect

    Yang, Song-Ling; Tsai, Cheng-Che; Hong, Cheng-Shong; Chu, Sheng-Yuan; Center for Micro/Nano Science and Technology and Research Center for Energy Technology and Strategy, National Cheng Kung University, Tainan 701, Taiwan, ROC

    2012-04-15

    Graphical abstract: NKN ceramics with a sintering aid CuTa{sub 2}O{sub 6} (CT) doping increased the mechanical quality factor (Q{sub m}) and electromechanical coupling factor (k{sub p}). Highlights: Black-Right-Pointing-Pointer A new sintering aid CuTa{sub 2}O{sub 6} was developed to dope into NKN ceramics. Black-Right-Pointing-Pointer Dense NKN ceramics were obtained as CuTa{sub 2}O{sub 6} compound doping. Black-Right-Pointing-Pointer We find the soluble limit of CuTa{sub 2}O{sub 6} compound incorporated into NKN ceramics. Black-Right-Pointing-Pointer The maximum Q{sub m} and k{sub p} values were more than 1500 and 42%, respectively. Black-Right-Pointing-Pointer CuTa{sub 2}O{sub 6} compound is a better sintering aid compared with K{sub 5.3}Cu{sub 1.3}Ta{sub 10}O{sub 29}. -- Abstract: In this study, the effects of a sintering aid CuTa{sub 2}O{sub 6} (CT) on (Na{sub 0.5}K{sub 0.5})NbO{sub 3} (NKN) ceramics were investigated. The diffracted angles in XRD profiles decreased because the Nb-sites were replaced by Cu and Ta ions, causing the expansion of lattice volume. SEM images showed smaller grain sizes at a low concentration of CuTa{sub 2}O{sub 6}, and grain sizes increased as the concentration of CuTa{sub 2}O{sub 6} doping increased because of a liquid phase formed. When CuTa{sub 2}O{sub 6} dopants were doped into NKN ceramics, the T{sub O-T} and T{sub c} phase transitions decreased because the replacement of Ta{sup 5+} ions in the B-site. A high bulk density (4.595 g/cm{sup 3}) and electromechanical coupling factor (k{sub p}, k{sub t}) were enhanced when CT dopants were doped into NKN ceramics. Moreover, the mechanical quality factor (Q{sub m}) also increased from 67 to 1550. NKN ceramics with sintering aid CuTa{sub 2}O{sub 6} doping showed excellent piezoelectric properties: k{sub p}: 42.5%; k{sub t}: 49.1%; Q{sub m}: 1550; and d{sub 33}: 96 pC/N.

  13. Lead-free nanogenerator made from single ZnSnO3 microbelt.

    PubMed

    Wu, Jyh Ming; Xu, Chen; Zhang, Yan; Wang, Zhong Lin

    2012-05-22

    We demonstrated a single-microbelt nanogenerator first made using a ZnSnO(3) microbelt that generated an output power of ∼3 nW under a compressive and releasing strain of 0.8-1%. The ZnSnO(3) nanobelts/microbelts were synthesized using a vapor transfer process at 1173 K. The X-ray diffraction pattern shows that the microbelts belong to ZnSnO(3) with rhombohedral structure. An individual ZnSnO(3) microbelt was bonded at its ends on a flexible polystyrene substrate as a nanogenerator, which gives an output voltage and current of 100 mV and 30 nA, respectively, corresponding to an energy conversion efficiency of 4.2-6.6% (based on 0.8-1% strain). Our results show that ZnSnO(3) microbelts are one of the highly promising materials for lead-free piezoelectric energy harvesting. PMID:22482511

  14. Lead-free BaTiO3 nanowires-based flexible nanocomposite generator.

    PubMed

    Park, Kwi-Il; Bae, Soo Bin; Yang, Seong Ho; Lee, Hyung Ik; Lee, Kisu; Lee, Seung Jun

    2014-08-01

    We have synthesized BaTiO3 nanowires (NWs) via a simple hydrothermal method at low temperature and developed a lead-free, flexible nanocomposite generator (NCG) device by a simple, low-cost, and scalable spin-coating method. The hydrothermally grown BaTiO3 NWs are mixed in a polymer matrix without a toxic dispersion enhancer to produce a piezoelectric nanocomposite (p-NC). During periodical and regular bending and unbending motions, the NCG device fabricated by utilizing a BaTiO3 NWs-polydimethylsiloxane (PDMS) composite successfully harvests the output voltage of ∼ 7.0 V and current signals of ∼ 360 nA, which are utilized to drive a liquid crystal display (LCD). We also characterized the instantaneous power (∼ 1.2 μW) of the NCG device by calculating the load voltage and current through the connected external resistance. PMID:24967905

  15. Temperature dependent properties and poling effect of K4CuNb8O23 modified (Na0.5K0.5)NbO3 lead free piezoceramics

    NASA Astrophysics Data System (ADS)

    Chen, Qiang; Chen, Yu; Peng, Zhihang; Wu, Jiagang; Liu, Hong; Xiao, Dingquan; Yu, Ping; Zhu, Jiliang; Zhu, Jianguo

    2015-03-01

    Lead free piezoelectric ceramics (Na0.5K0.5)NbO3 modified by 4% mol. K4CuNb8O23 (abbreviated NKN:4KCN hereinafter) contain moderate piezoelectric constant d33 ˜ 100 pC N-1 and large mechanical quality factor Qm > 1000, showing possible replacement of the lead-based ones (Chen et al., J Appl. Phys. 102, 104109 (2007)). In terms of practical use, however, the temperature stability of NKN:4KCN is not clear to date. We made a systematic investigation on the properties versus temperature of NKN:4KCN to evaluate whether it can be practically used. In the range from room temperature (RT ˜ 25 °C) to 100 °C, the ferroelectricity of poled NKN:4KCN material is nearly temperature independent, remanent polarization Pr is about 27.6 ±1 μC cm-2. When the as-studied NKN:4KCN ceramics were thermal depolarized in temperature range from RT to 450 °C, piezoelectric constant d33 changed little, retaining about 99 pC N-1, 77 ± 3 pC N-1, from RT to 150 °C, 200 °C to 350 °C, respectively. The poled NKN:4KCN material showed higher orthorhombic to tetragonal phase transition temperature (TO-T ˜ 200 °C) compared to unpoled sample (TO-T ˜ 194 °C). Moreover, this kind of lead free material displayed negative temperature coefficient of frequency (TCF) and positive TCF in orthorhombic and tetragonal phase state, respectively. The TCF was about -360 ppm K-1 in the range from RT to 125 °C, close to some lead-based commercial ones. The significance of this work lies in evaluating whether such a material can be practically used or not. We believe such a material might be the most promising candidate for replacing lead-based ones in some areas in the future.

  16. Fabrication of piezoelectric ceramic fibers by extrusion of Pb(Zr, Ti)O3 powder and Pb(Zr, Ti)O3 sol mixture

    NASA Astrophysics Data System (ADS)

    Qiu, Jinhao; Tani, Junji; Kobayashi, Yoshimasa; Um, Tae Young; Takahashi, Hirofumi

    2003-06-01

    In this study, Pb(Zr, Ti)O3 (PZT) piezoelectric ceramic fibers were fabricated by extrusion from a mixture of PZT powder and PZT sol. The added PZT sol in this study played the role of a binder; the sol changed into crystalline PZT during sintering, and removal of additives before sintering was not required. To obtain the required PZT fibers, the sol viscosity adjustment condition, the mixture ratio of powder and sol for fiber extrusion, and the sintering condition for obtaining polycrystalline fibers were investigated. The PZT precursor solution was synthesized from lead acetate trihydrate, zirconium n-propoxide, and titanium isopropoxide by reflux at 120 °C for 3 h with 2-methoxyethanol. The appropriate adjustment of the spinnable sol was achieved by the addition of acetic acid to suppress the hydrolysis reaction and by curing the sol at 80 °C to promote the condensation of the sol. Green fibers with diameters of about 300µm were successfully extruded from the mixture of PZT powder and sol (powder:sol = 5- 8:1, molar ratio). The extruded fibers, sintered at 1200 °C, had a microstructure with 2- 6µm grains and had no pores or cracks. From the results of displacement behavior measurements, the PZT fibers fabricated by firing at 1200 °C in this study were considered to have the desired piezoelectric properties.

  17. A piezoelectrically actuated ball valve

    NASA Technical Reports Server (NTRS)

    Erwin, L. R.; Schwartz, H. W.; Teitelbaum, B. R.

    1972-01-01

    Bimorph strip composed of two layers of poled piezoelectric ceramic material closes and opens valve. Strip performs like capacitator, allowing initial inrush of current when valve is energized and then only small leakage current flows as valve remains energized.

  18. Preparation, crystal structure and enhanced bipolar response of 0.90BLNT-0.10BCT lead-free piezoceramics

    NASA Astrophysics Data System (ADS)

    Pal, Vijayeta; Kumar, A.; Thakur, O. P.; Dwivedi, R. K.

    2016-05-01

    In the present work, a solid solution of lead free 0.90[(Bi0.96La0.04)0.5Na0.5TiO3]-0.10(Ba0.90Ca0.10TiO3] (abbreviated as 0.90BLNT-0.10BCT) piezoceramics has been synthesized by semi-wet technique. X-ray diffraction pattern confirms the phase formation. Rietveld refinement of XRD data demonstrates the coexistence of rhombhohedral (R3c) + tetragonal (P4mm) phase at room temperature. Raman spectrum is also support the above analysis. A large enhancement in bipolar strain of 0.12 % and calculated normalized strain, d*33 (defined as Smax/Emax) ~ 265 pm/V at 40kV/cm has been observed for this composition as compared to pure BLNT specimen, which make possible it as a potential lead-free candidates for piezoelectric applications.

  19. Improved Piezoelectric Loudspeakers And Transducers

    NASA Technical Reports Server (NTRS)

    Regan, Curtis Randall; Jalink, Antony; Hellbaum, Richard F.; Rohrbach, Wayne W.

    1995-01-01

    Loudspeakers and related acoustic transducers of improved type feature both light weight and energy efficiency of piezoelectric transducers and mechanical coupling efficiency. Active component of transducer made from wafer of "rainbow" piezoelectric material, ceramic piezoelectric material chemically reduced on one face. Chemical treatment forms wafer into dishlike shallow section of sphere. Both faces then coated with electrically conductive surface layers serving as electrodes. Applications include high-fidelity loudspeakers, and underwater echo ranging devices.

  20. Nonlinear coefficients in lead-free CuO-(K,Na)NbO3 transducers

    NASA Astrophysics Data System (ADS)

    Liu, Yaoyang; Morita, Takeshi

    2015-07-01

    Hard piezoelectric materials usually require to be driven at a high vibration level. However, piezoelectrics under high stress show significant nonlinear behavior, which should be taken as one of the criteria. In this study, nonlinearity in lead-free CuO-(K,Na)NbO3 (CuO-KNN) transducers was investigated. In the burst-mode measurement, the transducers began free vibration after being excited by a burst voltage. The velocity decay rate and resonance frequency obtained from the velocity-time curve show high dependence on velocity amplitude. On the other hand, in the measured admittance curves at high voltage, around the resonant frequency, the values are not consecutive (jumping phenomenon); also, a hysteresis appears between the upward and downward sweeps, indicating the existence of nonlinearity. A model containing the nonlinear terms was proposed and adopted for fitting the admittance curves. From the curve fitting, the nonlinear coefficients and force factor of the CuO-KNN transducers could be determined and compared with those of Pb(Zr,Ti)O3 transducers.

  1. Lead-Free Experiment in a Space Environment

    NASA Technical Reports Server (NTRS)

    Blanche, J. F.; Strickland, S. M.

    2012-01-01

    This Technical Memorandum addresses the Lead-Free Technology Experiment in Space Environment that flew as part of the seventh Materials International Space Station Experiment outside the International Space Station for approximately 18 months. Its intent was to provide data on the performance of lead-free electronics in an actual space environment. Its postflight condition is compared to the preflight condition as well as to the condition of an identical package operating in parallel in the laboratory. Some tin whisker growth was seen on a flight board but the whiskers were few and short. There were no solder joint failures, no tin pest formation, and no significant intermetallic compound formation or growth on either the flight or ground units.

  2. Effects of SmCoO3 on the microstructure and piezoelectric properties of (Bi0.5Na0.5)0.94Ba0.06TiO3 ceramics

    NASA Astrophysics Data System (ADS)

    Shao, Lin; Chu, Ruiqing; Xu, Zhijun; Liu, Yong; Chen, Mingli; Zhao, Jianli; Li, Guorong

    2013-01-01

    (Bi0.5Na0.5)0.94Ba0.06TiO3 (abbreviated to BNBT6) ceramics doped with 0-0.6 mol.% SmCoO3 were synthesized by the conventional solid-state reaction method, and the effect of SmCoO3 addition on the dielectric and piezoelectric properties was investigated. X-ray diffraction (XRD) patterns show that SmCoO3 diffuses into the lattice of the BNBT6 ceramics to form a solid solution with a pure perovskite structure. SEM images indicate that the addition of SmCoO3 caused a remarkably promoted grain growth. Our results reveal that both the piezoelectric and electromechanical properties of BNBT6 ceramics could be greatly improved by certain amount of SmCoO3 substitutions. At room temperature, the BNBT6 ceramics doped with 0.4 mol.% SmCoO3 exhibit the optimum properties with high piezoelectric constant (d33=144 pC/N), high planar coupling factor (kp=29.1%), and high mechanical quality factor (Qm=219).

  3. Grain size effect on phase transition behavior and electrical properties of (Bi1/2K1/2)TiO3 piezoelectric ceramics

    NASA Astrophysics Data System (ADS)

    Hagiwara, Manabu; Fujihara, Shinobu

    2015-10-01

    Dense and phase-pure (Bi1/2K1/2)TiO3 (BKT) ceramics with various grain sizes from 0.18 to 1.01 µm were prepared by conventional sintering of a hydrothermally synthesized fine powder. The decrease in grain size resulted in the reductions in tetragonality, remanent polarization, and the piezoelectric d33 coefficient, whereas the room-temperature dielectric permittivity slightly increased with decreasing grain size. The measurement of the temperature dependence of permittivity revealed that BKT exhibited the spontaneous relaxor-to-normal ferroelectric (R-nFE) phase transition. It was also found that the maximum permittivity was decreased and the R-nFE transition was inhibited by the reduction in grain size. In this paper, on the basis of the observed grain-size-dependent phase transition behaviors, microstructural models are proposed for both coarse- and fine-grained BKT ceramics, and the mechanism underlying the grain size effect on the electrical properties is discussed.

  4. Giant electric-field-induced strain in lead-free piezoelectric materials

    PubMed Central

    Chen, Lan; Yang, Yurong; Meng, X. K.

    2016-01-01

    First-principles calculations are performed to investigate the structures, electrical, and magnetic properties of compressive BiFeO3 films under electric-field and pressure perpendicular to the films. A reversible electric-field-induced strain up 10% is achieved in the compressive BiFeO3 films. The giant strain originates from rhombohedral-tetragonal (R-T) phase transition under electric-filed, and is recoverable from tetragonal-rhombohedral (T-R) phase transition by compressive stress. Additionally, the weak ferromagnetism in BiFeO3 films is largely changed in R-T phase transition under electric-filed and T-R phase transition under pressure – reminiscent of magnetoelectric effect and magnetoelastic effect. These results suggest exciting device opportunities arising from the giant filed-induced strain, large magnetoelectric effect and magnetoelastic effect. PMID:27139526

  5. Giant electric-field-induced strain in lead-free piezoelectric materials.

    PubMed

    Chen, Lan; Yang, Yurong; Meng, X K

    2016-01-01

    First-principles calculations are performed to investigate the structures, electrical, and magnetic properties of compressive BiFeO3 films under electric-field and pressure perpendicular to the films. A reversible electric-field-induced strain up 10% is achieved in the compressive BiFeO3 films. The giant strain originates from rhombohedral-tetragonal (R-T) phase transition under electric-filed, and is recoverable from tetragonal-rhombohedral (T-R) phase transition by compressive stress. Additionally, the weak ferromagnetism in BiFeO3 films is largely changed in R-T phase transition under electric-filed and T-R phase transition under pressure - reminiscent of magnetoelectric effect and magnetoelastic effect. These results suggest exciting device opportunities arising from the giant filed-induced strain, large magnetoelectric effect and magnetoelastic effect. PMID:27139526

  6. Microstructural studies of nanocrystalline barium zirconium titanate (BZT) for piezoelectric applications

    NASA Astrophysics Data System (ADS)

    Jamil, Nor Huwaida Janil @; Izzuddin, Izura; Zainuddin, Zalita; Jumali, Mohammad Hafizuddin Haji

    2015-09-01

    Lead-free piezoelectric ceramics based on barium titanate (BaTiO3) with substitution of Zr4+ were prepared using sol-gel method. The Ba(ZrxTi1-x)O3, (BZT) powders with x = 0.0, 0.1, 0.2 and 0.3 were pressed into pellets and sintered at 1250 °C for 2 h. Focusing on the effect of Zr4+ substitutions into BaTiO3 perovskite system, the phase transition and microstructural properties of BZT ceramics were studied using XRD, SEM and EDX spectroscopy. All X-ray diffractograms were fitted using Pawley refinement model. The XRD diffractograms revealed the progressive phase transition from tetragonal to cubic phase as Zr content increased. The crystallite exhibited decreasing trend and was supported by shrinkage in grain size. The EDX analysis confirmed the successful substitution of Ti4+ with Zr4+ in BaTiO3 crystal.

  7. Solid-state conversion of (94-x)(Na1/2Bi1/2)TiO3-6BaTiO3-x(K1/2Na1/2)NbO3 single crystals and their enhanced converse piezoelectric properties

    NASA Astrophysics Data System (ADS)

    Park, Ji-Hoon; Kang, Suk-Joong L.

    2016-01-01

    (94-x)(Na1/2Bi1/2)TiO3-6BaTiO3-x(K1/2Na1/2)NbO3 (NBT-6BT-xKNN) piezoelectric ceramics have notable potential for replacing lead containing piezoelectric ceramics in actuator applications due to their exceptionally large strain. However, a high electric field for producing a large strain and a large hysteresis are critical issues that should be resolved for practical actuator applications. In an attempt to address these issues and optimize the piezoelectric performance, we fabricated NBT-6BT-xKNN (x = 0 - 5) piezoelectric single crystals with a size of 8 x 8x 10 mm by the solid-state single crystal growth method and systematically measured their electrical properties. With increased addition of KNN to replace NBT, the ferroelectricity and piezoelectricity of the fabricated [001] NBT-6BT-xKNN single crystals decreased, but their unipolar strain and hysteresis were considerably improved. For NBT-6BT-5KNN single crystals, the largest maximum strain (Smax) was 0.57% at 6 kV/mm, showing a converse piezoelectric constant (Smax/Emax) of 950 pm/V, and their hysteresis in the unipolar S-E curve was 12% at 6kV/mm, which would be appropriate for some actuator applications. Our results demonstrate the applicability of the produced single crystals as lead-free piezoelectric actuator components.

  8. High Temperature Piezoelectric Drill

    NASA Technical Reports Server (NTRS)

    Bao, Xiaoqi; Scott, James; Boudreau, Kate; Bar-Cohen, Yoseph; Sherrit, Stewart; Badescu, Mircea; Shrout, Tom; Zhang, Shujun

    2009-01-01

    The current NASA Decadal mission planning effort has identified Venus as a significant scientific target for a surface in-situ sampling/analyzing mission. The Venus environment represents several extremes including high temperature (460 deg C), high pressure (9 MPa), and potentially corrosive (condensed sulfuric acid droplets that adhere to surfaces during entry) environments. This technology challenge requires new rock sampling tools for these extreme conditions. Piezoelectric materials can potentially operate over a wide temperature range. Single crystals, like LiNbO3, have a Curie temperature that is higher than 1000 deg C and the piezoelectric ceramics Bismuth Titanate higher than 600 deg C. A study of the feasibility of producing piezoelectric drills that can operate in the temperature range up to 500 deg C was conducted. The study includes the high temperature properties investigations of engineering materials and piezoelectric ceramics with different formulas and doping. The drilling performances of a prototype Ultrasonic/Sonic Drill/Corer (USDC) using high temperate piezoelectric ceramics and single crystal were tested at temperature up to 500 deg C. The detailed results of our study and a discussion of the future work on performance improvements are presented in this paper.

  9. UHV piezoelectric translator

    SciTech Connect

    Oversluizen, T.; Watson, G.

    1985-01-01

    A UHV compatible piezoelectric translator has been developed to correct for angular misalignments in the crysals of a UHV x-ray monochromator. The unit is small, bakeable to 150/sup 0/C, and uses only ceramic materials for insulation. We report on the construction details, vacuum compatibility, mechanical properties, and uses of the device.

  10. Active Piezoelectric Diaphragms

    NASA Technical Reports Server (NTRS)

    Bryant, Robert G.; Effinger, Robert T., IV; Aranda, Isaiah, Jr.; Copeland, Ben M.; Covington, Ed W., III

    2002-01-01

    Several active piezoelectric diaphragms were fabricated by placing unelectroded piezoelectric disks between copper clad films patterned with Inter-Circulating Electrodes "ICE". When a voltage potential is applied to the electrodes, the result is radially distributed electric field that mechanically strains the piezo-ceramic along the Z-axis (perpendicular to the applied electric field), rather than the expected in-plane (XY-axis) direction. Unlike other out of plane piezoelectric actuators, which are benders, these Radial Field Diaphragms (RFDs) strain concentrically yet afford high displacements while maintaining a constant circumference. This paper covers the fabrication and characterization of these diaphragms as a function of poling field strength, ceramic diameter and line spacing, as well as the surface topography, the resulting strain field and displacement as a function of applied voltage ranging from DC to 10 Hz.

  11. Ferroelectric, dielectric and piezoelectric properties of Sr{sub 0.6}(BiNa){sub 0.2}Bi{sub 2}Nb{sub 2}O{sub 9} ceramics

    SciTech Connect

    Fang, Pinyang Xi, Zengzhe; Long, Wei; Li, Xiaojuan

    2013-11-15

    Graphical abstract: The oxygen vacancy was confirmed by the left figure and the role of oxygen vacancy on the piezoelectric properties was discussed. - Highlights: • The d{sub 33}, ρ and T{sub c} were found to be 22 pC/N, ρ ∼ 10{sup 6} Ω cm and 586 °C. • The electromechanical properties: k{sub p} ∼ 5.0%, k{sub t} ∼ 8.7% and Q{sub m} ∼ 651. • The oxygen vacancy is responsible for electrical properties at high temperature. - Abstract: Aurivillius-type ceramic, Sr{sub 0.6}(BiNa){sub 0.2}Bi{sub 2}Nb{sub 2}O{sub 9} (SBNBN), was synthesized by using conventional solid-state processing. Phase structure and microstructural morphology were confirmed by X-ray diffraction analyses (XRD) and the scanning electron microscopy (SEM). Dielectric, piezoelectric and electromechanical properties of the SBNBN ceramic were investigated in detail. Curie temperature (T{sub c}), piezoelectric coefficient (d{sub 33}), electromechanical coupling coefficient k{sub p}, k{sub t} and quality factor Q{sub m} of the SBNBN ceramic were found to be 586.5 °C, 22 pC/N, 5.0%, 8.7% and 651, respectively. In addition, the reasons for varieties of the resistivity and dielectric properties at high temperature were also discussed.

  12. Investigation of high Curie temperature (1-x)BiSc{sub 1-y}Fe{sub y}O{sub 3}-xPbTiO{sub 3} piezoelectric ceramics

    SciTech Connect

    Sterianou, I.; Sinclair, D. C.; Reaney, I. M.; Comyn, T. P.; Bell, A. J.

    2009-10-15

    Ceramics around the morphotropic phase boundary (MPB) in the (1-x)BiSc{sub 1-y}Fe{sub y}O{sub 3}-xPbTiO{sub 3} solid solution were fabricated. For y=0.5, ceramics were single phase, and piezoelectric coefficients (d{sub 33}) and electromechanical coupling coefficients (k{sub p}) for MPB compositions were 300 pC/N and 0.49, respectively; a level of piezoelectric activity similar to that of hard, lead zirconate titanate compositions but with T{sub C}approx60 deg. C higher at approx440 deg. C. For ceramics with y>=0.7, dielectric measurements in combination with diffraction contrast transmission electron microscopy revealed the existence of two ferroelectric phases for most PbTiO{sub 3} contents studied. The presence of two ferroelectric phases was associated with a decrease in piezoelectric activity and although raw materials costs for y=0.7 and 0.8 with respect to y=0 were significantly lower (less Sc{sub 2}O{sub 3}) and T{sub C} greater (approx500 deg. C), d{sub 33} (approx100 pC/N) and k{sub p} (0.18) were too low to be commercially useful for actuator applications.

  13. Lead-free 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 nanowires for energy harvesting

    NASA Astrophysics Data System (ADS)

    Zhou, Zhi; Bowland, Christopher C.; Malakooti, Mohammad H.; Tang, Haixiong; Sodano, Henry A.

    2016-02-01

    Lead-free piezoelectric nanowires (NWs) show strong potential in sensing and energy harvesting applications due to their flexibility and ability to convert mechanical energy to electric energy. Currently, most lead-free piezoelectric NWs are produced through low yield synthesis methods and result in low electromechanical coupling, which limit their efficiency as energy harvesters. In order to alleviate these issues, a scalable method is developed to synthesize perovskite type 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 (BZT-BCT) NWs with high piezoelectric coupling coefficient. The piezoelectric coupling coefficient of the BZT-BCT NWs is measured by a refined piezoresponse force microscopy (PFM) testing method and shows the highest reported coupling coefficient for lead-free piezoelectric nanowires of 90 +/- 5 pm V-1. Flexible nanocomposites utilizing dispersed BZT-BCT NWs are fabricated to demonstrate an energy harvesting application with an open circuit voltage of up to 6.25 V and a power density of up to 2.25 μW cm-3. The high electromechanical coupling coefficient and high power density demonstrated with these lead-free NWs produced via a scalable synthesis method shows the potential for high performance NW-based devices.

  14. Lead-free 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 nanowires for energy harvesting.

    PubMed

    Zhou, Zhi; Bowland, Christopher C; Malakooti, Mohammad H; Tang, Haixiong; Sodano, Henry A

    2016-02-25

    Lead-free piezoelectric nanowires (NWs) show strong potential in sensing and energy harvesting applications due to their flexibility and ability to convert mechanical energy to electric energy. Currently, most lead-free piezoelectric NWs are produced through low yield synthesis methods and result in low electromechanical coupling, which limit their efficiency as energy harvesters. In order to alleviate these issues, a scalable method is developed to synthesize perovskite type 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 (BZT-BCT) NWs with high piezoelectric coupling coefficient. The piezoelectric coupling coefficient of the BZT-BCT NWs is measured by a refined piezoresponse force microscopy (PFM) testing method and shows the highest reported coupling coefficient for lead-free piezoelectric nanowires of 90 ± 5 pm V(-1). Flexible nanocomposites utilizing dispersed BZT-BCT NWs are fabricated to demonstrate an energy harvesting application with an open circuit voltage of up to 6.25 V and a power density of up to 2.25 μW cm(-3). The high electromechanical coupling coefficient and high power density demonstrated with these lead-free NWs produced via a scalable synthesis method shows the potential for high performance NW-based devices. PMID:26868967

  15. Ferroelectric and piezoelectric properties of high temperature (Bi,La)FeO3-Bi(Zn1/2Ti1/2)O3-PbTiO3 ceramics at rhombohedral/tetragonal coexistent phase

    NASA Astrophysics Data System (ADS)

    Zhang, Linlin; Hou, Xianbo; Yu, Jian

    2015-08-01

    In this article, some high Curie temperature ferroelectric piezoceramics of perovskite-structured BiFeO3-Bi(Zn1/2Ti1/2)O3-PbTiO3 (BF-BZT-PT) solid solutions were prepared using fine-ball milling and solid state reaction method. X-ray diffraction measurements exhibited those BF-BZT-PT ceramics being crystallized in rhombohedral/tetragonal coexistent phase while scanning electron microscopy showed their microstructure grain size about 200 nm. It was found that the ferroelectric Curie temperature increases up to 630 °C with increasing BF content in those BF-BZT-PT ceramics and that their ferroelectric and piezoelectric properties were strongly dependent on compositions and sintering temperature. A good combination of ferroelectric and piezoelectric property of remanent polarization Pr = 18 µC/cm2, coercive field Ec = 64 kV/cm, piezoelectric constant d33 = 41 pC/N, dielectric constant \\varepsilon 33\\text{T}/\\varepsilon 0 = 258, loss tan δ = 0.023, and Curie temperature TC = 582 °C was obtained for 0.59BF-0.15BZT-0.26PT ceramics sintered at 780 °C for 10 h and poled under 8.4 kV/mm at 120 °C for 20 min. In comparison with tetragonal 0.50BF-0.15BZT-0.35PT ceramics reported previously by the author group, rhombohedral/tetragonal-coexistent-phased 0.59BF-0.15BZT-0.26PT ceramics exhibited a higher piezoresponse, and contemporarily, La-substitution was found playing the same role of enhancing piezoresponse and reducing Curie temperature. Of most interest, a good piezoelectric property of d33 = 24 pC/N, ɛr = 217, tan δ = 0.020, and TC = 630 °C was obtained for 0.66BF-0.15BZT-0.19PT ceramics prepared by two-step sintering with 850-750 °C for 10 h and poled under 9.0 kV/mm at 120 °C for 20 min, which is better than that of commercial K-15 bismuth titanate ceramics with d33 = 18 pC/N, \\varepsilon 33\\text{T}/\\varepsilon 0 = 140, tan δ = 0.03, and TC ˜ 620 °C. Like the case of Pb(Zr,Ti)O3, BF-BZT-PT perovskites are becoming important to design high temperature high performance ferroelectric piezoceramics through adjusting composition and crystallographic structure.

  16. Lead-free BaTiO3 nanowires-based flexible nanocomposite generator

    NASA Astrophysics Data System (ADS)

    Park, Kwi-Il; Bae, Soo Bin; Yang, Seong Ho; Lee, Hyung Ik; Lee, Kisu; Lee, Seung Jun

    2014-07-01

    We have synthesized BaTiO3 nanowires (NWs) via a simple hydrothermal method at low temperature and developed a lead-free, flexible nanocomposite generator (NCG) device by a simple, low-cost, and scalable spin-coating method. The hydrothermally grown BaTiO3 NWs are mixed in a polymer matrix without a toxic dispersion enhancer to produce a piezoelectric nanocomposite (p-NC). During periodical and regular bending and unbending motions, the NCG device fabricated by utilizing a BaTiO3 NWs-polydimethylsiloxane (PDMS) composite successfully harvests the output voltage of ~7.0 V and current signals of ~360 nA, which are utilized to drive a liquid crystal display (LCD). We also characterized the instantaneous power (~1.2 μW) of the NCG device by calculating the load voltage and current through the connected external resistance.We have synthesized BaTiO3 nanowires (NWs) via a simple hydrothermal method at low temperature and developed a lead-free, flexible nanocomposite generator (NCG) device by a simple, low-cost, and scalable spin-coating method. The hydrothermally grown BaTiO3 NWs are mixed in a polymer matrix without a toxic dispersion enhancer to produce a piezoelectric nanocomposite (p-NC). During periodical and regular bending and unbending motions, the NCG device fabricated by utilizing a BaTiO3 NWs-polydimethylsiloxane (PDMS) composite successfully harvests the output voltage of ~7.0 V and current signals of ~360 nA, which are utilized to drive a liquid crystal display (LCD). We also characterized the instantaneous power (~1.2 μW) of the NCG device by calculating the load voltage and current through the connected external resistance. Electronic supplementary information (ESI) available: PDF materials involve the linear superposition test results (Fig. S1) and the durability test results (Fig. S2) of BaTiO3 NWs-based NCG device. A video file (Video S1) shows the power up of an LCD screen by the NCG device without any external energy source. See DOI: 10.1039/c4nr02246g

  17. Visualization of polar nanoregions in lead-free relaxors via piezoresponse force microscopy in torsional dual AC resonance tracking mode.

    PubMed

    Liu, Na; Dittmer, Robert; Stark, Robert W; Dietz, Christian

    2015-07-21

    Polar nanoregions (PNRs) play a key role in the functionality of relaxor ferroelectrics; however, visualizing them in lead-free relaxor ferroelectrics with high lateral resolution is still challenging. Thus, we studied herein the local ferroelectric domain distribution of the lead-free bismuth-based (1 -x)(Bi1/2Na1/2TiO3-Bi1/2K1/2TiO3) -x(Bi1/2Mg1/2TiO3) piezoceramics which show a relaxor behavior using dual AC resonance tracking (DART) piezoresponse force microscopy (PFM). By using excitation frequencies at either side of the contact resonance peak of the torsional cantilever vibration, an enhanced contrast in the amplitude and phase images of the piezoresponse can be achieved. Additionally, this tracking technique reduces the topographical crosstalk while mapping the local electromechanical properties. The true drive amplitude, drive phase, contact resonant frequency and quality factor can be estimated from DART-PFM data obtained with vertically or torsionally vibrating cantilevers. This procedure yields a three-dimensional quantitative map of the local piezoelectric properties of the relaxor ferroelectric samples. With this approach, torsional DART allowed for the visualization of fine substructures within the monodomains, suggesting the existence of PNRs in relaxor ferroelectrics. The domain structures of the PNRs were visualized with high precision, and the local electromechanical characteristics of the lead-free relaxor ferroelectrics were quantitatively mapped. PMID:26106953

  18. High T{sub c} lead-free BaTiO{sub 3}-(Bi{sub 1/2}Na{sub 1/2})TiO{sub 3} positive temperature coefficient of resistivity ceramics with electrically heterogeneous structure

    SciTech Connect

    Xiang Pinghua; Takeda, Hiroaki; Shiosaki, Tadashi

    2007-10-15

    A distinct positive temperature coefficient of resistivity effect has been observed in BaTiO{sub 3}-(Bi{sub 1/2}Na{sub 1/2})TiO{sub 3} (BT-BNT) ceramics sintered in a N{sub 2} flow with low O{sub 2} concentration. With the addition of BNT, the samples exhibit resistivity jumps of {approx}10{sup 3}-10{sup 5} starting at {approx}190-210 deg. C. X-ray diffraction results indicate that the BNT phase and BT phase formed a solid solution during sintering. An electrically heterogeneous structure, consisting of the grain interiors, outer grain shells, and grain boundaries, is revealed by the complex impedance analyses. The observed dc resistivity jump is attributed to the rapid resistivity rise in both grain boundaries and grain shells.

  19. Theoretical and experimental research on the influence of multiple piezoelectric effects on physical parameters of piezoelectric actuator

    NASA Astrophysics Data System (ADS)

    Shi, Liping; Zhou, Haimin; Huang, Jie; Tan, Jiliang

    2015-04-01

    Compared with the traditional actuator of machinery and electricity, the piezoelectric actuator has the advantages of a compact structure, small volume, no mechanical friction, athermancy and no electromagnetic interference. Therefore, it has high application value in the fields of MEMS, bioengineering, medical science and so on. This article draws conclusions from the influence of multiple piezoelectric effects on the physical parameters (dielectric coefficient, equivalent capacity, energy conversion and piezoelectric coefficient) of piezoelectric actuators. These data from theoretical and experimental research show the following: (1) The rate between the dielectric coefficient of piezoelectric in mechanical freedom and clamping is obtained from the secondary direct piezoelectric effect, which enhances the dielectric property, increases the dielectric coefficient and decreases the coefficient of dielectric isolation; (2) Under external field, En ( ex ) = E 1 , exterior stress T = 0, that is to say, under the boundary condition of mechanical freedom, piezoelectric can store electric energy and elasticity, which obtains power density, elastic density and an electromechanical coupling factor; (3) According to the piezoelectric strain Si ( 1 ) , piezoelectric displacement Dm ( 2 ) and piezoelectric strain Si ( 3 ) of multiple piezoelectric effects, when the dielectric coefficient of the first converse piezoelectric effect ɛ33 is 1326 and the dielectric coefficient of the secondary direct piezoelectric effect increases to 3336, the dielectric coefficient of the ceramic chip increases. When the piezoelectric coefficient of the first converse piezoelectric effect d33 is 595 and the piezoelectric coefficient of the secondary direct piezoelectric effect decreases to 240, the piezoelectric coefficient of the ceramic chip will decrease. It is of major significance both in the applications and in basic theory to research the influence of multiple piezoelectric effects on the physical parameters of piezoelectric actuators. On the one hand, this can further increase the control precision of piezoelectric actuators. On the other hand, it can be applied to research on the physical parameters and self-sensing actuators, like piezoelectric quartz and piezoelectric ceramic self-sensing actuators, which will be of great service for MEMS.

  20. Lead-free bearing alloys for engine applications

    NASA Astrophysics Data System (ADS)

    Ratke, Lorenz; Ågren, John; Ludwig, Andreas; Tonn, Babette; Gránásy, László; Mathiesen, Ragnvald; Arnberg, Lars; Anger, Gerd; Reifenhäuser, Bernd; Lauer, Michael; Garen, Rune; Gust, Edgar

    2005-10-01

    Recent developments to reduce the fuel consumption, emission and air pollution, size and weight of engines for automotive, truck, ship propulsion and electrical power generation lead to temperature and load conditions within the engines that cannot be borne by conventional bearings. Presently, only costly multilayer bearings with electroplated or sputtered surface coatings can cope with the load/speed combinations required. Ecological considerations in recent years led to a ban by the European Commission on the use of lead in cars a problem for the standard bronze-lead bearing material. This MAP project is therefore developing an aluminium-based lead-free bearing material with sufficient hardness, wear and friction properties and good corrosion resistance. Only alloys made of components immiscible in the molten state can meet the demanding requirements. Space experimentation plays a crucial role in optimising the cast microstructure for such applications.

  1. Crystal Structure, Piezoelectric and Dielectric Properties of (Li, Ce)4+, Nb5+ and Mn2+ Co-doped CaBi4Ti4O15 High-Temperature Ceramics

    NASA Astrophysics Data System (ADS)

    Xin, Deqiong; Chen, Qiang; Wu, Jiagang; Bao, Shaoming; Zhang, Wen; Xiao, Dingquan; Zhu, Jianguo

    2016-05-01

    Bismuth-layered structured ceramics Ca0.85(Li,Ce)0.075Bi4Ti4-x Nb x O15-0.01MnCO3 were prepared by the conventional solid-state reaction method. The evolution of microstructure and corresponding electrical properties were studied. All the samples presented a single bismuth layered-structural phase with m = 4, indicating that (Li, Ce)4+, Nb5+ and Mn2+ adequately enter into the pseudo-perovskite structure and form solid solutions. It was found that Ca0.85(Li,Ce)0.075Bi4Ti3.98Nb0.02O15-0.01MnCO3 (CBTLCM-0.02Nb) ceramics possess the optimum electrical properties. The piezoelectric coefficient d 33, dielectric constant ɛ r, loss tanδ, planar electromechanical coupling factor k p and Curie-temperature T C of CBTLCM-0.02Nb ceramics were found to be ˜19.6 pC/N, 160, 0.16%, 8.1% and 767°C, respectively. Furthermore, the thermal depoling behavior demonstrates that the d 33 value of x = 0.02 content remains at 16.8 pC/N after annealing at 500°C. These results suggest that the (Li, Ce)4+-, Nb5+- and Mn2+-doped CBT-based ceramics are promising candidates for high-temperature piezoelectric applications.

  2. Modeling of piezoelectric ceramic vibrators including thermal effects. Part III. Bond graph model for one-dimensional heat conduction

    SciTech Connect

    Moon, W.; Busch-Vishniac, I.J.

    1997-03-01

    A new bond graph model for conduction heat transfer is developed, and applied to thermal energy balance in the piezoelectric thickness vibrator. In formulation of the heat conduction model, the mechanical and electrical effects are included. Hence, it can be directly applied to the temperature-dependent thickness vibrator. For the purpose of evaluation of the new method, one-dimensional heat conduction excluding other variable effects is compared with the results of the analytic solutions in simple cases. The simulation illustrates the validity and the accuracy of the model. Although the model is applied to the one-dimensional case only, the method can be easily used for general heat conduction problems. {copyright} {ital 1997 Acoustical Society of America.}

  3. Effects of lanthanum doping on the dielectric, piezoelectric properties and defect mechanism of PZN-PZT ceramics prepared by hot pressing

    NASA Astrophysics Data System (ADS)

    Zeng, X.; Ding, A. L.; Deng, G. C.; Liu, T.; Zheng, X. S.

    2005-07-01

    The structure and electrical properties of Pb(Zn1/3Nb2/3)0.3(Zr0.55Ti0.45)0.7O3-xLa ceramics system by hot pressing with the composition near to the morphotropic phase boundary (MPB) were investigated as a function of La doping content. PZN-PZT specimens shifted from rhombohedral phase towards tetragonal phase with increasing La doping. Dielectric spectroscopy showed that La doping decreased dielectric permittivity maximum remarkably, and increased the degree of diffuse phase transition (DPT) with lower ferroelectric phase transition temperature. The growth of 1:1 chemically ordered domains through La doping was considered the cause of the dielectric dispersion. The high piezoelectric coefficient, d33 (716 pC/N), and electromechanical coupling factor, kp (0.62) were obtained in spite of existence of the pyrochlore phase. Oxygen vacancy conduction was the dominant mechanism. La doping reduced the concentration of oxygen vacancies, thus increased the electrical resistivity.

  4. Theoretical and experimental investigation of traveling wave propagation on a several- millimeter-long cylindrical pipe driven by piezoelectric ceramic tubes.

    PubMed

    Sun, Dongming; Wang, Sheng; Hata, Seiichi; Sakurai, Junpei; Shimokohbe, Akira

    2010-07-01

    A novel method is presented for investigation of the traveling wave propagation generated on a thin film pipe with a short length of several millimeters. As a bridge to connect two piezoelectric ceramic (lead zirconate titanate, PZT) tubes, a thin-film metallic glass (TFMG) pipe is fabricated by a new technique of rotating magnetron sputtering. The vibrator combines the vibration of the axial mode of the PZT tube and the radial mode of the TFMG pipe. Theoretical analyses of the TFMG pipe and PZT tube, with a comparison of the finite element modeling, clarify the vibration characteristics so that the proper geometrical sizes, suitable boundary conditions, and driving voltage signals are designed. In the experiment, the designed vibrator was fabricated and the vibration characteristics were measured by a laser Doppler vibrometer system. The pure traveling wave propagation obtained theoretically and experimentally demonstrates the validity of this work. This study shows a new way to achieve a pure traveling wave on a short cylindrical pipe driven by PZT tubes. PMID:20639154

  5. Interface cracks in piezoelectric materials

    NASA Astrophysics Data System (ADS)

    Govorukha, V.; Kamlah, M.; Loboda, V.; Lapusta, Y.

    2016-02-01

    Due to their intrinsic electromechanical coupling behavior, piezoelectric materials are widely used in sensors, actuators and other modern technologies. It is well known that piezoelectric ceramics are very brittle and susceptible to fracture. In many cases, fracture occurs at interfaces as debonding and cracks. This leads to an undesired degradation of electrical and mechanical performance. Because of the practical and fundamental importance of the problem, interface cracks in piezoelectric materials have been actively studied in the last few decades. This review provides a comprehensive survey of recent works on cracks situated at the interface of two materials, at least one of which has piezoelectric or piezoelectromagnetic properties. Different electric boundary conditions along the crack faces are discussed. The oscillating and contact zone models for in-plane straight interface cracks between two dissimilar piezoelectric materials or between piezoelectric and non-piezoelectric ones are reviewed. Different peculiarities related to the investigation of interface cracks in piezoelectric materials for the anti-plane case, for functionally graded and thermopiezoelectric materials are presented. Papers related to magnetoelectroelastic bimaterials, to steady state motion of interface cracks in piezoelectric bimaterials and to circular arc-cracks at the interface of piezoelectric materials are reviewed, and various methods used to address these problems are discussed. The review concludes with an outlook on future research directions.

  6. Raman, dielectric and variable range hopping nature of Gd2O3-doped K0.5N0.5NbO3 piezoelectric ceramics

    NASA Astrophysics Data System (ADS)

    Peddigari, Mahesh; Dobbidi, Pamu

    2015-10-01

    (K0.5Na0.5)NbO3 (KNN) + x wt% Gd2O3 (x = 0 -1.5) ceramics have been prepared by conventional solid state reaction method. The effect of Gd2O3 on the structural, microstructural and dielectric properties of KNN ceramics were studied systematically. The effect of Gd2O3 on phase transformation from orthorhombic to psuedocubic structure is explained interms of changes in the internal vibration modes of NbO6 octahedra. The Raman intensity of the stretching mode v1 enhanced and shifted toward higher wavenumber with Gd2O3 concentration, which is attributed to the increase in polarizability and change in the O-Nb-O bond angles. Microstructural analysis revealed that the grain size of the KNN ceramics decreases from 2.26 ± 1.07 μm to 0.35 ± 0.13 μm and becomes homogenous with an increase in Gd2O3 concentration. The frequency dependent dielectric spectra are analyzed by using Havriliak-Negami function. The fitted symmetry parameter and relaxation time (τ) are found to be 0.914 and 8.78 × 10-10 ± 5.5 × 10-11 s, respectively for the sample doped with x = 1.0. The addition of Gd2O3 to the KNN shifted the polymorphic phase transition orthorhombic to tetragonal transition temperature (TO-T) from 199oC to 85oC with enhanced dielectric permittivity (ɛ' = 1139 at 1 MHz). The sample with x = 1.0, shown a high dielectric permittivity (ɛ' = 879) and low dielectric loss (<5%) in the broad temperature range (-140oC - 150oC) with the Curie temperature 307 oC can have the potential for high temperature piezoelectric and tunable RF circuit applications. The temperature dependent AC-conductivity follows the variable range hopping conduction mechanism by obtaining the slope -0.25 from the ln[ln(ρac)] versus ln(T) graph in the temperature range of 133 K-308 K. The effect of Gd2O3 on the Mott's parameters such as density of states (N(EF)), hopping length (RH), and hopping energy (WH) have been discussed.

  7. Aging in the relaxor and ferroelectric state of Fe-doped (1-x)(Bi{sub 1/2}Na{sub 1/2})TiO₃-xBaTiO₃ piezoelectric ceramics

    SciTech Connect

    Sapper, Eva; Dittmer, Robert; Rödel, Jürgen; Damjanovic, Dragan; Erdem, Emre; Keeble, David J.; Jo, Wook; Granzow, Torsten

    2014-09-14

    Aging of piezoelectric properties was investigated in lead-free (1–x)(Bi{sub 1/2}Na{sub 1/2})TiO₃-xBaTiO₃ doped with 1at.% Fe. The relaxor character of the un-poled material prevents macroscopic aging effects, while in the field-induced ferroelectric phase aging phenomena are similar to those found in lead zirconate titanate or barium titanate. Most prominent aging effects are the development of an internal bias field and the decrease of switchable polarization. These effects are temperature activated, and can be explained in the framework of defect complex reorientation. This picture is further supported by electron paramagnetic resonance spectra indicating the existence of (Fe{sub Ti}´-V{sub O}{sup ••}){sup •} defect complexes in the Fe-doped material.

  8. Relationship between Poling Characteristics and Phase Boundaries of Potassium-Sodium Niobate Ceramics.

    PubMed

    Zheng, Ting; Wu, Jiagang

    2016-04-13

    The controversy about the optimum poling conditions of (K,Na)NbO3 (KNN)-based lead-free ceramics was still unresolved and the relationships between poling characteristics and phase boundary types were rarely mentioned. Here, we tried to unveil the relationships between poling characteristics and phase boundary types of these ceramics. The optimum poling temperatures should be chosen near their corresponding phase transition temperatures. In addition, a large piezoelectricity can be attained in the ceramics with a multiphase coexistence under a lower poling electric field (ceramics with different phase boundaries can be fully poled after the measurement of P-E loops, where the d33 values match those of the corresponding ones poled by the DC electric field. We believe that this modified poling process can benefit the improved piezoelectricity of KNN-based ceramics. PMID:27007478

  9. Low-cost (0.1BiYbO3-0.9PbTiO3)-PbZrO3-xMn high Curie temperature piezoelectric ceramics with improved high-temperature performance

    NASA Astrophysics Data System (ADS)

    Wang, Yunli; Cai, Kai; Shao, Tianmin; Zhao, Qian; Guo, Dong

    2015-04-01

    Here, we report the structure and performance of a low-cost high Curie temperature (TC) Mn-doped ternary BiYbO3-Pb(Zr,Ti)O3 (BY-PZT-xMn) perovskite piezoelectric ceramic system. The partial substitution of Mn for the A-site Pb, B-site Ti and Zr of the ternary system enhanced both the piezoelectric coefficient and the mechanical quality factor, indicating that the variable valence element induced combinatory soft and hard doped characteristics. The improved electrical performance was found to be related to the improved density and homogeneity, and a correlation between the piezoelectricity and the grain size was also observed. More importantly, a Mn doping level of less than 0.8 mol. % also obviously enhanced the thermal stability of the samples, as reflected by the higher TC and depolarization temperature (Td) measured via both in situ Berlincourt method and annealing experiments, and a correlation between TC and tetragonality of BY-PZT-xMn system was observed. The sample with 0.8 mol. % Mn showed a remarkable overall performance with a d33 of 246 pC/N and a TC around 400 °C, which is expected to be promising for high temperature piezoelectric device applications.

  10. Local and Global Properties of a Lead-Free Solder

    NASA Astrophysics Data System (ADS)

    Ma, Z.; Chalon, F.; Leroy, R.; Ranganathan, N.; Beake, B. D.

    2013-07-01

    Elastic and viscous properties including Young's modulus, hardness, creep rate sensitivity, and fatigue resistance of Sn-1.2Ag-0.5Cu-0.05Ni lead-free solder have been investigated. The properties of bulk specimens and in situ solder balls are compared. Experiments show good correlations of Young's modulus and creep rate sensitivity between conventional measurements and nanoindentation results on bulk specimens. Further mechanical properties of the beach-ball microstructure in solder balls are characterized by nanoindentation. The load-partial unload technique has been used to determine the variation in mechanical properties with increasing depth of penetration into the intermetallic inclusions in the in situ solder. The fatigue resistances of the bulk specimens and solder balls are compared by using the novel nanoimpact method. In comparison with bulk specimens, it is found that in situ solder has higher Young's modulus, lower creep strain rate sensitivity, and better fatigue resistance. The effects of soldering and the scale differences strongly affect the mechanical and fatigue properties of in situ solder.

  11. Giant energy density in [001]-textured Pb(Mg1/3Nb2/3)O3-PbZrO3-PbTiO3 piezoelectric ceramics

    SciTech Connect

    Yan, Yongke; Cho, Kyung-Hoon; Maurya, Deepam; Kumar, Amit; Kalinin, Sergei V; Khachaturyan, Armen; Priya, Shashank

    2013-01-01

    Pb(Zr,Ti)O3 (PZT) based compositions have been challenging to texture or grow in a single crystal form due to the incongruent melting point of ZrO2. Here we demonstrate the method for achieving 90% textured PZT-based ceramics and further show that it can provide highest known energy density in piezoelectric materials through enhancement of piezoelectric charge and voltage coefficients (d and g). Our method provides more than 5 increase in the ratio d(textured)/d(random). A giant magnitude of d g coefficient with value of 59 000 10 15 m2 N 1 (comparable to that of the single crystal counterpart and 359% higher than that of the best commercial compositions) was obtained.

  12. Mechanical Properties and Microstructure Investigation of Lead Free Solder

    NASA Technical Reports Server (NTRS)

    Wang, Qing; Gail, William F.; Johnson, R. Wayne; Strickland, Mark; Blanche, Jim

    2005-01-01

    While the electronics industry appears to be focusing on Sn-Ag-Cu as the alloy of choice for lead free electronics assembly, ,the exact composition varies by geographic region, supplier and user. Add to that dissolved copper and silver from the printed circuit board traces and surface finish, and there can be significant variation in the final solder joint composition. A systematic study of the mechanical and microstructural properties of Sn-Ag-Cu alloys with Ag varying from 2wt% to 4wt% and Cu varying from 0.5wt% to lSwt%, was undertaken in this research study. Different sample preparation techniques (water quenched, oil quenched and water quenched followed by reflow) were explored and the resulting microstructure compared to that of a typical reflowed lead free chip scale package (CSP) solder joint. Tensile properties (modulus, 0.2% yield strength and the ultimate tensile strength) and creep behavior of selected alloy compositions (Sn-4Ag-1 X u , Sn-4Ag-OSCu, Sn- 2Ag-1 X u , Sn-2Ag-OSCu, Sn-3.5Ag-O.SCu) were determined for three conditions: as- cast; aged for 100 hours at 125OC; and aged for 250 hours at 125OC. There was no significant difference in Young's Modulus as a function of alloy composition. After an initial decrease in modulus after 100 hours at 125"C, there was an insignificant change with further aging. The distribution of 0.2% strain yield stress and ultimate tensile strength as a function of alloy composition was more significant and decreased with aging time and temperature. The microstructures of these alloys were examined using light and scanning electron microscopy (LM and SEM) respectively and SEM based energy dispersive x-ray spectroscopy (EDS). Fracture surface and cross-section analysis were performed on the specimens after creep testing. The creep testing results and the effect of high temperature aging on mechanical properties is presented for the oil quenched samples. In general the microstructure of oil quenched specimen exhibited a eutectic region of Sn with moderately dispersed Ag3Sn intermetallic, surrounded by a dendritic Sn-rich phase. The SEM images of the fracture surface indicated the presence of a tough shear surface at the initial cavity break area and a break line in the middle of specimen along the failure direction. A hyperbolic-sine creep model was adopted and used to fit the creep experiment data. The effect on the mechanical properties by adding the quaternary element bismuth to the Sn-3.5Ag-0.8Cu alloy was measured and compared with the mechanical properties of the ternary alloys. The results of this research study provide necessary data for the modeling of solder joint reliability for a range of Sn-Ag-Cu compositions and a baseline for evaluating the effects of subsequent quaternary additions.

  13. Study of Lead Free Ferroelectric Films for New Solar Cells

    SciTech Connect

    Fasquelle, D.; Mascot, M.; Carru, J. C.; Hikam, M.; Iriani, Y.; Soegijono, B.

    2009-09-14

    We report on the deposition by a sol-gel process of Ba{sub 0.8}Sr{sub 0.2}TiO{sub 3} and Ba{sub 0.9}Sr{sub 0.1}TiO{sub 3} films on platinum coated silicon substrates. X-Ray diffraction patterns show that the films are (111) preferentially oriented. The surface morphology is smooth, without cracks and the grain size is about 50 nm as determined by AFM and SEM. The dielectric constant measured from 10{sup 2} to 10{sup 6} Hz decreases slightly and is around 400 at 10{sup 4} Hz. The losses are constant in a first approximation for a 1.5 {mu}m thick BST(80/20) film with a value of 0.03 at 10 kHz. The existence of an hysteresis cycle attests that the films, whatever their thickness, are in a ferroelectric state. Pyroelectric coefficients have been determined and the best figure of merit obtained on BST(90/10) at 293 K and 10 kHz is of 149 {mu}C/m{sup 3}/K. The best dielectric and pyroelectric properties (tg{delta} = 0.006 at 1 MHz, tunability = 30%, {gamma} = 340 {mu}C/m{sup 2}/K) were obtained on the 400 nm BST(90/10) film. Work is in progress to characterize the piezoelectric and photovoltaic properties of our BST films.

  14. Variation of Piezoelectric properties and mechanisms across the relaxor-like/Ferroelectric continuum in BiFeO3- (K0.5Bi0.5)TiO3-PbTiO3 ceramics.

    PubMed

    Bennett, James; Shrout, Thomas R; Zhang, Shujun; Owston, Heather E; Stevenson, Tim J; Esat, Faye; Bell, Andrew J; Comyn, T P

    2015-01-01

    1- x - y)BiFeO3-x(K0.5Bi0.5)TiO3-yPbTiO3 (BFKBT- PT) piezoelectric ceramics were investigated across the compositional space and contrasted against the xBiFeO3- (1-x)(K0.5Bi0.5)TiO3 (BF-KBT) system, whereby a range of relaxor-like/ferroelectric behavior was observed. Structural and piezoelectric properties were closely related to the PbTiO3 concentration; below a critical concentration, relaxor-like behavior was identified. The mechanisms governing the piezoelectric behavior were investigated with structural, electrical, and imaging techniques. X-ray diffraction established that longrange non-centrosymmetric crystallographic order was evident above a critical PbTiO3 concentration, y > 0.1125. Commensurate with the structural analysis, electric-field-induced strain responses showed electrostrictive behavior in the PbTiO3-reduced compositions, with increased piezoelectric switching in PbTiO3-rich compositions. Positive-up-negative-down (PUND) analysis was used to confirm electric-field-induced polarization measurements, elucidating that the addition of PbTiO3 increased the switchable polarization and ferroelectric ordering. Piezoresponse force microscopy (PFM) of the BF-KBT-PT system exhibited typical domain patterns above a critical PbTiO3 threshold, with no ferroelectric domains observed in the BF-KBT system in the pseudocubic region. Doping of BiFeO3-PbTiO3 has been unsuccessful in the search for hightemperature materials that offer satisfactory piezoelectric properties; however, this system demonstrates that the partial substitution of alternative end-members can be an effective method. The partial substitution of PbTiO3 into BF-KBT enables long-range non-centrosymmetric crystallographic order, resulting in increased polar order and TC, compared with the pseudocubic region. The search for novel high-temperature piezoelectric ceramics can therefore exploit the accommodating nature of the perovskite family, which allows significant variance in chemical and physical characters in the exploration of new solid-solutions. PMID:25585388

  15. Low-Temperature Sintering of (Bi,Na)0.83Ba0.17TiO3-0.2 wt % CuO Piezoelectric Ceramics from Nanopowders

    NASA Astrophysics Data System (ADS)

    Lv, Junhua; Karaki, Tomoaki; Adachi, Masatoshi

    2011-01-01

    Using (Bi0.5Na0.5)0.83Ba0.17TiO3 nanopowders synthesized by an oxalate precursor route, 0.2-wt %-CuO-doped ceramics can be sintered at a low temperature of 880 °C. The shrinkage rate is 16.5%, the relative density Dr is 98%, the relative dielectric constant ɛT33/ɛ0 (1 kHz) is 705, the loss tan δ (1 kHz) is 2.50%, the electromechanical coupling factor kp is 13.6%, and the piezoelectric charge coefficient d33 is 105 pC/N.

  16. Enhanced magnetoelectric effects in composite of piezoelectric ceramics, rare-earth iron alloys, and shape-optimized nanocrystalline alloys.

    PubMed

    Zhang, Jitao; Li, Ping; Wen, Yumei; He, Wei; Yang, Aichao; Lu, Caijiang

    2014-03-01

    An enhancement for magnetoelectric (ME) effects is studied in a three-phase ME architecture consisting of two magnetostrictive Terfenol-D (Tb(0.3)Dy(0.7)Fe(1.92)) plates, a piezoelectric PZT (Pb(Zr,Ti)O3) plate, and a pair of shape-optimized FeCuNbSiB nanocrystalline alloys. By modifying the conventional shape of the magnetic flux concentrator, the shape-optimized flux concentrator has an improved effective permeability (?(eff)) due to the shape-induced demagnetizing effect at its end surface. The flux concentrator concentrates and amplifies the external magnetic flux into Terfenol-D plate by means of changing its internal flux concentrating manner. Consequently, more flux lines can be uniformly concentrated into Terfenol-D plates. The effective piezomagnetic coefficients (d(33m)) of Terfenol-D plate and the ME voltage coefficients (?(ME)) can be further improved under a lower magnetic bias field. The dynamic magneto-elastic properties and the effective magnetic induction of Terfenol-D are taken into account to derive the enhanced effective ME voltage coefficients (?(ME,eff)), the consistency of experimental results and theoretical analyses verifies this enhancement. The experimental results demonstrate that the maximum d(33m) in our proposed architecture achieves 22.48?nm/A under a bias of 114 Oe. The maximum ?(ME) in the bias magnetic range 0-900 Oe reaches 84.73 mV/Oe under the low frequency of 1 kHz, and 2.996 V/Oe under the resonance frequency of 102.3 kHz, respectively. It exhibits a 1.43 times larger piezomagnetic coefficient and a 1.87 times higher ME voltage coefficient under a smaller magnetic bias of 82 Oe than those of a conventional Terfenol-D/PZT/Terfenol-D composite. These shape-induced magnetoelectric behaviors provide the possibility of using this ME architecture in ultra-sensitive magnetic sensors. PMID:24689597

  17. Visualization of polar nanoregions in lead-free relaxors via piezoresponse force microscopy in torsional dual AC resonance tracking mode

    NASA Astrophysics Data System (ADS)

    Liu, Na; Dittmer, Robert; Stark, Robert W.; Dietz, Christian

    2015-07-01

    Polar nanoregions (PNRs) play a key role in the functionality of relaxor ferroelectrics; however, visualizing them in lead-free relaxor ferroelectrics with high lateral resolution is still challenging. Thus, we studied herein the local ferroelectric domain distribution of the lead-free bismuth-based (1 - x)(Bi1/2Na1/2TiO3-Bi1/2K1/2TiO3) - x(Bi1/2Mg1/2TiO3) piezoceramics which show a relaxor behavior using dual AC resonance tracking (DART) piezoresponse force microscopy (PFM). By using excitation frequencies at either side of the contact resonance peak of the torsional cantilever vibration, an enhanced contrast in the amplitude and phase images of the piezoresponse can be achieved. Additionally, this tracking technique reduces the topographical crosstalk while mapping the local electromechanical properties. The true drive amplitude, drive phase, contact resonant frequency and quality factor can be estimated from DART-PFM data obtained with vertically or torsionally vibrating cantilevers. This procedure yields a three-dimensional quantitative map of the local piezoelectric properties of the relaxor ferroelectric samples. With this approach, torsional DART allowed for the visualization of fine substructures within the monodomains, suggesting the existence of PNRs in relaxor ferroelectrics. The domain structures of the PNRs were visualized with high precision, and the local electromechanical characteristics of the lead-free relaxor ferroelectrics were quantitatively mapped.Polar nanoregions (PNRs) play a key role in the functionality of relaxor ferroelectrics; however, visualizing them in lead-free relaxor ferroelectrics with high lateral resolution is still challenging. Thus, we studied herein the local ferroelectric domain distribution of the lead-free bismuth-based (1 - x)(Bi1/2Na1/2TiO3-Bi1/2K1/2TiO3) - x(Bi1/2Mg1/2TiO3) piezoceramics which show a relaxor behavior using dual AC resonance tracking (DART) piezoresponse force microscopy (PFM). By using excitation frequencies at either side of the contact resonance peak of the torsional cantilever vibration, an enhanced contrast in the amplitude and phase images of the piezoresponse can be achieved. Additionally, this tracking technique reduces the topographical crosstalk while mapping the local electromechanical properties. The true drive amplitude, drive phase, contact resonant frequency and quality factor can be estimated from DART-PFM data obtained with vertically or torsionally vibrating cantilevers. This procedure yields a three-dimensional quantitative map of the local piezoelectric properties of the relaxor ferroelectric samples. With this approach, torsional DART allowed for the visualization of fine substructures within the monodomains, suggesting the existence of PNRs in relaxor ferroelectrics. The domain structures of the PNRs were visualized with high precision, and the local electromechanical characteristics of the lead-free relaxor ferroelectrics were quantitatively mapped. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr01326g

  18. Piezoelectric Polymers

    NASA Technical Reports Server (NTRS)

    Harrison, J. S.; Ounaies, Z.; Bushnell, Dennis M. (Technical Monitor)

    2001-01-01

    The purpose of this review is to detail the current theoretical understanding of the origin of piezoelectric and ferroelectric phenomena in polymers; to present the state-of-the-art in piezoelectric polymers and emerging material systems that exhibit promising properties; and to discuss key characterization methods, fundamental modeling approaches, and applications of piezoelectric polymers. Piezoelectric polymers have been known to exist for more than forty years, but in recent years they have gained notoriety as a valuable class of smart materials.

  19. Lead-Free Propellant for Propellant Actuated Devices

    NASA Technical Reports Server (NTRS)

    Goodwin, John L.

    2000-01-01

    Naval Surface Warfare Center, Indian Head Division's CAD/PAD Department has been working to remove toxic compounds from our products for about a decade. In 1992, we embarked on an effort to develop a lead-free double base propellant to replace that of a foreign sole source. At the time there were availability concerns. In 1995, the department developed a strategic proposal to include a wider range of products. Efforts included such efforts as removing lead sheathing from linear explosives and replacing lead azide and lead styphnate compounds. This paper will discuss efforts specifically related to developing non-leaded double base propellant for use in various Propellant Actuated Devices (PADs) for aircrew escape systems. The propellants can replace their leaded counterparts, mitigating lead handling, processing, or toxic exposure to the environment and personnel. This work eliminates the use of leaded compounds, replacing them with a more environmentally benign metal-organic salt. Historically double-base propellants have held an advantage over other families of energetic materials through their relative insensitivity of the burning rate to changes in temperature and pressure. This desirable ballistic effect has been obtained with the use of a lead-organic salt alone or in a physical mixture with a copper-organic salt, or more recently with a lead-copper complex. These ballistic modifiers are typically added to the double-base 'paste' prior to gelatinization on heated calendars or one type or another. The effect of constant burning rate over a pressure range is called a 'plateau' while an even more beneficial effect of decreasing burning rate with increasing pressure is termed a 'mesa.' The latter effect results in very low temperature sensitivity of the propellant burning rate. Propellants with such effects are ideal tactical rocket motor propellants. The use of lead compounds poses a concern for the environment and personnel safety due to the metal's toxic nature when introduced into the atmosphere by propellant manufacturing, rocket firings, and disposal. Two separate programs are underway at Indian Head to replace the leaded ballistic modifiers in NOSIH-AA-2 and KU propellants. Although the system requirements were very different, the programs gained valuable information from one another throughout their course.

  20. Experiments to Demonstrate Piezoelectric and Pyroelectric Effects

    ERIC Educational Resources Information Center

    Erhart, Jirí

    2013-01-01

    Piezoelectric and pyroelectric materials are used in many current applications. The purpose of this paper is to explain the basic properties of pyroelectric and piezoelectric effects and demonstrate them in simple experiments. Pyroelectricity is presented on lead zirconium titanate (PZT) ceramics as an electric charge generated by the temperature…

  1. Experiments to Demonstrate Piezoelectric and Pyroelectric Effects

    ERIC Educational Resources Information Center

    Erhart, Jir

    2013-01-01

    Piezoelectric and pyroelectric materials are used in many current applications. The purpose of this paper is to explain the basic properties of pyroelectric and piezoelectric effects and demonstrate them in simple experiments. Pyroelectricity is presented on lead zirconium titanate (PZT) ceramics as an electric charge generated by the temperature

  2. Dielectric response and pyroelectric properties of lead-free ferroelectric Ba3(VO4)2

    NASA Astrophysics Data System (ADS)

    Pati, Biswajit; Choudhary, R. N. P.; Das, Piyush R.; Sutar, B. C.

    2015-03-01

    The current paper presents results of dielectric response, pyroelectric behavior and conductivity study of lead-free ferroelectric barium orthovanadate (Ba3(VO4)2 or Ba3V2O8) ceramic, for a wide range of temperature and frequency. An X-ray diffraction study suggests the formation of a single-phase compound in trigonal crystal system. The SEM micrograph of gold-coated pellet sample shows well-defined and homogeneous morphology. Detailed studies of dielectric parameters (ɛr and tan δ) of the compound as a function of temperature and frequency reveal their independence over a wide range of temperature and frequency. The nature of Polarization versus electric field (P-E) hysteresis loop of Ba3V2O8 at room temperature suggests its ferroelectric nature. The temperature dependence of pyroelectric coefficient and figure of merits of the sample support its dielectric response. The nature of variation of dc conductivity with temperature confirms the Arrhenius and negative temperature coefficient of resistance (NTCR) behavior of the material.

  3. Enhanced depolarization temperature in 0.90NBT-0.05KBT-0.05BT ceramics induced by BT nanowires

    NASA Astrophysics Data System (ADS)

    Cao, W. P.; Li, W. L.; Feng, Y.; Xu, D.; Wang, W.; Hou, Y. F.; Zhang, T. D.; Fei, W. D.

    2015-03-01

    The depolarization temperature (Td) of piezoelectric materials is an important figure of merit for their application at elevated temperatures. This study focuses on the effect of BaTiO3 (BT) nanowires on Td and piezoelectric properties of morphotropic-phase-boundary 0.90NBT-0.05KBT-0.05BT ceramics. The results reveal that BaTiO3 nanowires can pin the domain wall, leading to the increase of coercive field (Ec) from 21.06 kV/cm to 34.99 kV/cm. The Td value of 0.90NBT-0.05KBT-0.05BT ceramics can be enhanced approximately 20 C when using BT nanowires instead of BT solution as the raw material. Meanwhile, at the same polarization conditions, the piezoelectric constant of the ceramic added BT nanowires (172 pC/N) is decreased but still remains a larger value compared with those of other lead-free ceramics. The results imply that the addition of BT nanowires into NBT-KBT is a very effective route to improve Td.

  4. Piezoelectric valve

    SciTech Connect

    Petrenko, Serhiy Fedorovich

    2013-01-15

    A motorized valve has a housing having an inlet and an outlet to be connected to a pipeline, a saddle connected with the housing, a turn plug having a rod, the turn plug cooperating with the saddle, and a drive for turning the valve body and formed as a piezoelectric drive, the piezoelectric drive including a piezoelectric generator of radially directed standing acoustic waves, which is connected with the housing and is connectable with a pulse current source, and a rotor operatively connected with the piezoelectric generator and kinematically connected with the rod of the turn plug so as to turn the turn plug when the rotor is actuated by the piezoelectric generator.

  5. Mediating the contradiction of d33 and TC in potassium-sodium niobate lead-free piezoceramics.

    PubMed

    Cheng, Xiaojing; Wu, Jiagang; Wang, Xiaopeng; Zhang, Binyu; Lou, Xiaojie; Wang, Xiangjian; Xiao, Dingquan; Zhu, Jianguo

    2013-11-13

    For potassium-sodium niobate, the piezoelectric constant (d33) was usually improved by sacrificing the Curie temperature (TC). In this work, a material system of 0.992(K0.46Na0.54)0.965Li0.035Nb(1-x)Sb(x)O3-0.008BiScO3 has been designed and prepared with the aim of achieving both a large d33 and a high TC at the same time. The chemical compositions are found to be homogeneously distributed in the ceramics. The introduction of Sc is found to be responsible for different grain sizes. The rhombohedral-tetragonal phase coexistence zone lies in the composition range of 0.02ceramic is thermally stable in terms of ferroelectric properties. The change in the domain-wall activities induced by the configuration variation of defect dipoles upon annealing is believed to be responsible for the variation in the d33 at different temperatures. The ceramic with x = 0.025 shows a good comprehensive performance of d33 ? 325 pC/N and k(p) ? 48%, together with a high T(C) of ~358 C, demonstrating that this material system is a promising candidate for high-temperature piezoelectric applications. PMID:24219128

  6. Continuous cross-over from ferroelectric to relaxor state and piezoelectric properties of BaTiO{sub 3}-BaZrO{sub 3}-CaTiO{sub 3} single crystals

    SciTech Connect

    Benabdallah, F.; Veber, P. Prakasam, M.; Viraphong, O.; Maglione, M.; Shimamura, K.

    2014-04-14

    Optimal properties like piezoelectricity can be found in polarizable materials for which the structure changes sharply under small composition variations in the vicinity of their morphotropic phase boundary or the triple point in their isobaric temperature-composition phase diagram. In the latter, lead-free (Ba{sub 0.850}Ca{sub 0.150})(Ti{sub 0.900}Zr{sub 0.100})O{sub 3} ceramics exhibit outstanding piezoelectric coefficients. For the first time, we report the growth of piezoelectric lead-free single crystals in the BaTiO{sub 3}-BaZrO{sub 3}-CaTiO{sub 3} pseudo-ternary system. The stoichiometry control in the CaO-BaO-TiO{sub 2}-ZrO{sub 2} solid solution led to single crystals with various compositions ranging from (Ba{sub 0.857}Ca{sub 0.143})(Ti{sub 0.928}Zr{sub 0.072})O{sub 3} to (Ba{sub 0.953}Ca{sub 0.047})(Ti{sub 0.427}Zr{sub 0.573})O{sub 3}. We evidenced a continuous cross-over from a ferroelectric state at high titanium content to a relaxor one on increasing the zirconium content. Such a property tuning is rather seldom observed in lead-free ferroelectrics and confirms what was already reported for ceramics. Single crystal with (Ba{sub 0.838}Ca{sub 0.162})(Ti{sub 0.854}Zr{sub 0.146})O{sub 3} composition, which has been grown and oriented along [001] crystallographic direction, displayed electromechanical coefficients d{sub 31} and k{sub 31} of 93 pC.N{sup −1} and 0.18, respectively, near the room temperature (T = 305 K)

  7. The pyroelectric behavior of lead free ferroelectric ceramics in thermally stimulated depolarization current measurements

    NASA Astrophysics Data System (ADS)

    González-Abreu, Y.; Peláiz-Barranco, A.; Garcia-Wong, A. C.; Guerra, J. D. S.

    2012-06-01

    The present paper shows a detailed analysis on the thermally stimulated processes in barium modified SrBi2Nb2O9 ferroelectric bi-layered perovskite, which is one of the most promising candidates for non-volatile random access memory applications because of its excellent fatigue-resistant properties. A numerical method is used to separate the real pyroelectric current from the other thermally stimulated processes. A discharge due to the space-charge injected during the poling process, the pyroelectric response, and a conductive process are discussed in a wide temperature range from ferroelectric to paraelectric phase. The pyroelectric response is separated from the other components to evaluate the polarization behavior and some pyroelectric parameters. The remanent polarization, the pyroelectric coefficient, and the merit figure are evaluated, which show good results.

  8. Microstructure and piezoelectric properties of 0.95(Na{sub 0.5}K{sub 0.5})NbO{sub 3}-0.05BaTiO{sub 3} ceramics

    SciTech Connect

    Park, Hwi-Yeol; Ahn, Cheol-Woo; Song, Hyun-Cheol; Lee, Jong-Heun; Nahm, Sahn; Uchino, Kenji; Lee, Hyeung-Gyu; Lee, Hwack-Joo

    2006-08-07

    For 0.95(Na{sub 0.5}K{sub 0.5})NbO{sub 3}-0.05BaTiO{sub 3} (0.95NKN-0.05BT) ceramics sintered at 1040-1075 deg. C, abnormal grain growth occurred but the grain size decreased when the sintering temperature exceeded 1075 deg. C. The dielectric constant ({epsilon}{sub 3}{sup T}/{epsilon}{sub 3}), electromechanical coupling factor (k{sub p}), and piezoelectric constant (d{sub 33}) were considerably increased with increasing relative density and grain size. Evaporation of Na{sub 2}O deteriorated the piezoelectric properties by decreasing the resistivity. To minimize Na{sub 2}O evaporation, specimens were muffled with 0.95NKN-0.05BT powders during the sintering. Improved piezoelectric properties of d{sub 33}=225 pC/N, k{sub p}=36%, and {epsilon}{sub 3}{sup T}/{epsilon}{sub 3}=1058 were obtained for specimen sintered at 1060 deg. C for 2 h with muffling.

  9. Microstructural studies of AgNbO3 ceramic by using complex impedance spectroscopy

    NASA Astrophysics Data System (ADS)

    Gangaprasad, K.; Rao, T. Durga; Niranjan, Manish K.; Asthana, Saket

    2015-06-01

    Lead-free piezoelectric silver niobate ceramic was synthesized by conventional solid state route. Room temperature X-ray diffraction pattern revealed that the sample crystallizes in single phase orthorhombic perovskite structure. Scanning electron micrographs of AgNbO3 ceramic showed that the average grain size is in the range 2-3 µm. The electrical properties were investigated by using impedance spectroscopy. Appearance of single semicircular arc in the Nyquist plot indicated the presence of grain contribution in the sample. Single RC parallel circuit model was employed to extract bulk capacitance (Cb), resistance (Rb) and electrical conductivity (σb). The activation energy calculated from impedance and modulus data indicate that same types of charge carriers (oxygen vacancy movements) are responsible for conduction and relaxation.

  10. Microstructural studies of AgNbO{sub 3} ceramic by using complex impedance spectroscopy

    SciTech Connect

    Gangaprasad, K.; Rao, T. Durga; Niranjan, Manish K.; Asthana, Saket

    2015-06-24

    Lead-free piezoelectric silver niobate ceramic was synthesized by conventional solid state route. Room temperature X-ray diffraction pattern revealed that the sample crystallizes in single phase orthorhombic perovskite structure. Scanning electron micrographs of AgNbO{sub 3} ceramic showed that the average grain size is in the range 2–3 µm. The electrical properties were investigated by using impedance spectroscopy. Appearance of single semicircular arc in the Nyquist plot indicated the presence of grain contribution in the sample. Single RC parallel circuit model was employed to extract bulk capacitance (C{sub b}), resistance (R{sub b}) and electrical conductivity (σ{sub b}). The activation energy calculated from impedance and modulus data indicate that same types of charge carriers (oxygen vacancy movements) are responsible for conduction and relaxation.

  11. Effect of the Addition of B2O3 on the Density, Microstructure, Dielectric, Piezoelectric and Ferroelectric Properties of K0.5Na0.5NbO3 Ceramics

    NASA Astrophysics Data System (ADS)

    Bharathi, P.; Varma, K. B. R.

    2014-02-01

    Boron oxide (B2O3) addition to pre-reacted K0.5Na0.5NbO3 (KNN) powders facilitated swift densification at relatively low sintering temperatures which was believed to be a key to minimize potassium and sodium loss. The base KNN powder was synthesized via solid-state reaction route. The different amounts (0.1-1 wt%) of B2O3 were-added, and ceramics were sintered at different temperatures and durations to optimize the amount of B2O3 needed to obtain KNN pellets with highest possible density and grain size. The 0.1 wt% B2O3-added KNN ceramics sintered at 1,100 °C for 1 h exhibited higher density (97 %). Scanning electron microscopy studies confirmed an increase in average grain size with increasing B2O3 content at appropriate temperature of sintering and duration. The B2O3-added KNN ceramics exhibited improved dielectric and piezoelectric properties at room temperature. For instance, 0.1 wt% B2O3-added KNN ceramic exhibited d 33 value of 116 pC/N which is much higher than that of pure KNN ceramics. Interestingly, all the B2O3-added (0.1-1 wt%) KNN ceramics exhibited polarization-electric field ( P vs. E) hysteresis loops at room temperature. The remnant polarization ( P r) and coercive field ( E c) values are dependent on the B2O3 content and crystallite size.

  12. Piezoelectric transformer structural modeling--a review.

    PubMed

    Yang, Jiashi

    2007-06-01

    A review on piezoelectric transformer structural modeling is presented. The operating principle and the basic behavior of piezoelectric transformers as governed by the linear theory of piezoelectricity are shown by a simple, theoretical analysis on a Rosen transformer based on extensional modes of a nonhomogeneous ceramic rod. Various transformers are classified according to their structural shapes, operating modes, and voltage transforming capability. Theoretical and numerical modeling results from the theory of piezoelectricity are reviewed. More advances modeling on thermal and nonlinear effects also are discussed. The article contains 167 references. PMID:17571814

  13. A role of BNLT compound addition on structure and properties of PZT ceramics

    NASA Astrophysics Data System (ADS)

    Jaita, P.; Watcharapasorn, A.; Jiansirisomboon, S.

    2010-09-01

    In this research, effects of lead-free bismuth sodium lanthanum titanate (BNLT) addition on structure and properties of lead zirconate titanate (PZT) ceramics were investigated. PZT ceramics with addition of 0.1-3.0 wt%BNLT were fabricated by a solid-state mixed oxide method and sintering at 1050-1200 °C for 2 h to obtain dense ceramics with at least 96% of theoretical density. X-ray diffraction indicated that complete solid solution occurred for all compositions. Phase identification showed both tetragonal and rhombohedral perovskite structure of PZT with no BNLT phase detected. Scanning electron micrographs of fractured PZT/BNLT ceramics showed equiaxed grain shape with both transgranular and intergranular fracture modes. Addition of BNLT was also found to reduce densification and effectively limited grain growth of PZT ceramic. Optimum Hv and KIC values were found to be 4.85 GPa and 1.56 MPa.m 1/2 for PZT/0.5 wt%BNLT sample. Among PZT/BNLT samples, room temperature dielectric constant seemed to be improved with increasing BNLT content. The maximum piezoelectric coefficient values were observed in pure PZT ceramic and were slightly decreased in BNLT-added samples. Small reduction of remanent polarization and coercive field in hysteresis loops was observed in BNLT-added samples, indicating a slightly suppressed ferroelectric interaction in this material system.

  14. Structure, Ferroelectric and Photoluminescence Properties of Eu-Doped CaBi4Ti4O15 Multifunctional Ceramics

    NASA Astrophysics Data System (ADS)

    Wu, Xiaochun; Xiao, Ping; Guo, Yongquan; Zheng, Qiaoji; Lin, Dunmin

    2015-10-01

    Lead-free multifunctional ceramics of CaBi4- x Eu x Ti4O15 were prepared by a traditional solid state method, and the effects of Eu doping on structure, ferroelectric, piezoelectric and photoluminescence properties of the ceramics were investigated. All the ceramics possessed typical bismuth layer structure with m = 4, belonging to orthorhombic symmetry, and no secondary phase was detected. The plate-like grains were observed in all the ceramics, and the grain growth was slightly inhibited after the addition of Eu. Saturated polarization hysteresis loops were observed for all the ceramics, and the remanent polarization P r decreased with Eu doping. The Eu-doped ceramics had a sharp excitation band centered at 465 nm due to the f-f transition from the 7F0 ground state to the 5D2 excited state of Eu3+. Under the excitation by 465 nm light, the main emission peaks located at 595 nm and 616 nm were obtained, which corresponds to the transition of 5D0-7F1, 5D0-7F2 levels in Eu3+, respectively. Our study shows that CaBi4Ti4O15 ceramics may be a promising multifunctional material for potential applications in optical-electro integration devices.

  15. Design, fabrication, and properties of 2-2 connectivity cement/polymer based piezoelectric composites with varied piezoelectric phase distribution

    PubMed Central

    Dongyu, Xu; Xin, Cheng; Banerjee, Sourav; Shifeng, Huang

    2014-01-01

    The laminated 2-2 connectivity cement/polymer based piezoelectric composites with varied piezoelectric phase distribution were fabricated by employing Lead Zirconium Titanate ceramic as active phase, and mixture of cement powder, epoxy resin, and hardener as matrix phase with a mass proportion of 4:4:1. The dielectric, piezoelectric, and electromechanical coupling properties of the composites were studied. The composites with large total volume fraction of piezoelectric phase have large piezoelectric strain constant and relative permittivity, and the piezoelectric and dielectric properties of the composites are independent of the dimensional variations of the piezoelectric ceramic layer. The composites with small total volume fraction of piezoelectric phase have large piezoelectric voltage constant, but also large dielectric loss. The composite with gradually increased dimension of piezoelectric ceramic layer has the smallest dielectric loss, and that with the gradually increased dimension of matrix layer has the largest piezoelectric voltage constant. The novel piezoelectric composites show potential applications in fabricating ultrasonic transducers with varied surface vibration amplitude of the transducer. PMID:25565725

  16. Design, fabrication, and properties of 2-2 connectivity cement/polymer based piezoelectric composites with varied piezoelectric phase distribution

    SciTech Connect

    Dongyu, Xu; Xin, Cheng; Shifeng, Huang; Banerjee, Sourav

    2014-12-28

    The laminated 2-2 connectivity cement/polymer based piezoelectric composites with varied piezoelectric phase distribution were fabricated by employing Lead Zirconium Titanate ceramic as active phase, and mixture of cement powder, epoxy resin, and hardener as matrix phase with a mass proportion of 4:4:1. The dielectric, piezoelectric, and electromechanical coupling properties of the composites were studied. The composites with large total volume fraction of piezoelectric phase have large piezoelectric strain constant and relative permittivity, and the piezoelectric and dielectric properties of the composites are independent of the dimensional variations of the piezoelectric ceramic layer. The composites with small total volume fraction of piezoelectric phase have large piezoelectric voltage constant, but also large dielectric loss. The composite with gradually increased dimension of piezoelectric ceramic layer has the smallest dielectric loss, and that with the gradually increased dimension of matrix layer has the largest piezoelectric voltage constant. The novel piezoelectric composites show potential applications in fabricating ultrasonic transducers with varied surface vibration amplitude of the transducer.

  17. Lead-Free vs Tin-Lead Reliability of Advanced Electronic Assemblies

    NASA Technical Reports Server (NTRS)

    Ghaffarian, Reza

    2005-01-01

    This presentation will provide the technical background and specific information published in literature related to reliability test, analyses, modeling, and associated issues for lead-free solder package assemblies in comparison to their tin-lead solder alloys. It also presents current understanding of lead-free thermal cycle test performance in support.

  18. Numerical and Analytical Design of Functionally Graded Piezoelectric Transducers

    NASA Astrophysics Data System (ADS)

    Rubio, Wilfredo Montealegre; Buiochi, Flavio; Adamowski, Julio C.; Silva, Emílio Carlos Nelli

    2008-02-01

    This paper presents analytical and finite element methods to model broadband transducers with a graded piezoelectric parameter. The application of FGM (Functionally Graded Materials) concept to piezoelectric transducer design allows the design of composite transducers without interface between materials (e.g. piezoelectric ceramic and backing material), due to the continuous change of property values. Thus, large improvements can be achieved in their performance characteristics, mainly generating short-time waveform ultrasonic pulses. Nevertheless, recent research on functionally graded piezoelectric transducers shows lack of studies that compare numerical and analytical approaches used in their design. In this work analytical and numerical models of FGM piezoelectric transducers are developed to analyze the effects of piezoelectric material gradation, specifically, in ultrasonic applications. In addition, results using FGM piezoelectric transducers are compared with non-FGM piezoelectric transducers. We concluded that the developed modeling techniques are accurate, providing a useful tool for designing FGM piezoelectric transducers.

  19. Synthesis and Characterization of Piezoelectric (Bi1/2Na1/2)TiO3 Films by a Hydrothermal Method

    NASA Astrophysics Data System (ADS)

    Xu, Fangchao; Kusukawa, Kazuhiro

    Thin films of lead-free piezoelectric ceramics (Bi1/2Na1/2)TiO3 (abbreviated as BNT) were prepared on pure titanium substrates by a hydrothermal method. The properties of BNT films synthesized from the reaction solution with various contents of bismuth and titanium were investigated using SEM, EDX, XRD and other instruments. Moreover, the effects of the concentrations of starting materials on permittivity and piezoelectric effect of deposited BNT films were discussed. The results showed that an impurity of Bi2O3 crystal was produced on the surfaces of all deposited films. With assumption of deposited films as an system of (1-x) (Bi1/2Na1/2)TiO3-xBi2O3, the BNT content was calculated from the Bi/Ti ratio of the EDX results. The optimized synthesis condition was determined on the evaluation target of the calculated BNT content. In addition, the unimorph cantilever type actuators were fabricated by BNT deposited samples, and their piezoelectric responses were measured at their resonance frequencies under AC field. It was noted that the piezoelectric effect of the deposited BNT film was greatly dependent on its crystallization level.

  20. Room temperature nonlinear magnetoelectric effect in lead-free and Nb-doped AlFeO{sub 3} compositions

    SciTech Connect

    Cótica, Luiz F.; Santos, Guilherme M.; Santos, Ivair A.; Freitas, Valdirlei F.; Coelho, Adelino A.; Pal, Madhuparna; Guo, Ruyan; Bhalla, Amar S.; Garcia, Ducinei; Eiras, José A.

    2015-02-14

    It is still a challenging problem to obtain technologically useful materials displaying strong magnetoelectric coupling at room temperature. In the search for new effects and materials to achieve this kind of coupling, a nonlinear magnetoelectric effect was proposed in the magnetically disordered relaxor ferroelectric materials. In this context, the aluminum iron oxide (AlFeO{sub 3}), a room temperature ferroelectric relaxor and magnetic spin glass compound, emerges as an attractive lead-free magnetoelectric material along with nonlinear magnetoelectric effects. In this work, static, dynamic, and temperature dependent ferroic and magnetoelectric properties in lead-free AlFeO{sub 3} and 2 at. % Nb-doped AlFeO{sub 3} multiferroic magnetoelectric compositions are studied. Pyroelectric and magnetic measurements show changes in ferroelectric and magnetic states close to each other (∼200 K). The magnetoelectric coefficient behavior as a function of H{sub bias} suggests a room temperature nonlinear magnetoelectric coupling in both single-phase and Nb-doped AlFeO{sub 3}-based ceramic compositions.

  1. Effects of SrZrO3 addition on piezoelectric properties of Bi0.5(Na0.8K0.2)0.5TiO3 ceramic

    NASA Astrophysics Data System (ADS)

    Iida, Daiki; Ogawa, Hirotaka; Kan, Akinori; Takahashi, Susumu; Moriyama, Tohru

    2015-10-01

    (1 - x)Bi0.5(Na0.8K0.2)0.5TiO3-xSrZrO3 [(1 - x)BNKT-xSZ] ceramics were synthesized by conventional solid-state reaction methods, and their ferroelectric and piezoelectric properties were investigated in this study. The X-ray powder diffraction profiles of the ceramics showed a single phase in the composition range of 0-0.07 the formation of morphotropic phase boundary between rhombohedral and tetragonal phases was suggested at compositions lower than x = 0.01. From the temperature dependence of dielectric properties, both the depolarization temperature and transition temperature from a rhombohedral phase to a tetragonal phase decreased, depending on the composition x. A pinched polarization-electric field (P-E) hysteresis loop was obtained for x = 0.005, suggesting the coexistence of ferroelectric and antiferroelectric phases. The remanent polarization and coercive field of the ceramics decreased with increasing composition x, whereas d33 improved from 116 to 191 pC/N in the composition range of 0-0.005.

  2. Dielectric and piezoelectric properties of <001> fiber-textured 0.675Pb(Mg1/3Nb2/3)O3-0.325PbTiO3 ceramics

    NASA Astrophysics Data System (ADS)

    Sabolsky, Edward M.; Trolier-McKinstry, Susan; Messing, Gary L.

    2003-04-01

    The 0.675Pb(Mg1/3Nb2/3)O3-0.325PbTiO3 (PMN-32.5PT) ceramic composition (with 1 wt. % excess PbO) was fiber textured in the <001> direction by the templated grain growth process using 5 vol % oriented {001}-BaTiO3 platelet crystals as the templates. The templated ceramics annealed at 1150 °C for 5 h attained texture fractions as high as 0.9. The fiber-textured samples showed an increase in the piezoelectric, electromechanical coupling, and compliance coefficients when poled and measured in the <001>-textured direction. The low drive field (<5 kV/cm) d33 coefficients in the <001>, measured directly from unipolar strain-field measurements, were ˜1150 pC/N. This d33 coefficient is 1.2-1.5 times greater than randomly oriented samples. The poled ɛmax and ɛrt for a 0.9-textured PMN-32.5PT ceramic were 21 500 and 2450, respectively. Factors limiting further property improvements are discussed.

  3. FOREWORD: Focus on innovation in ceramics research in East Asia Focus on innovation in ceramics research in East Asia

    NASA Astrophysics Data System (ADS)

    Kato, Akio; Hishita, Shunichi; Osada, Minoru; Haneda, Hajime

    2010-10-01

    Ceramics, as broadly defined, include all materials other than organic substances and metals, either crystalline or amorphous. They have been used by humans since early history and have contributed considerably to improving the quality of our life. In most cases, however, high-temperature treatment is necessary to prepare ceramics. This burdens the environment and there is therefore a great need for new ceramics processing methods. Recent technologically advanced ceramics are often composed of nanocrystallites, which have great potential for innovation in terms of exploring practical applications of nanomaterials and, consequently, reducing the environmental load. The ceramics industry had long flourished in Asia, particularly in East Asia, and even today, this region is leading the development of related materials. In line with these traditions, Japanese and Korean ceramics societies have been co-sponsoring seminars on ceramics since the 1980s. Having become more international in scope and context, a series of these seminars is now known as the International Japan-Korea Seminar on Ceramics. This focus issue contains eight key articles presented at the 26th International Japan-Korea Seminar on Ceramics held on 24-26 November 2010 at the Tsukuba International Congress Center. In particular, Fabbri et al review electrode materials for protonic solid-oxide fuel cells, and Kamiya et al outline the present situation and future prospects for transparent transistors, particularly those based on amorphous In-Ga-Zn-O films. Eitel et al discuss the progress in engineering high-strain lead-free piezoelectric ceramics. Kim and Kumar review a simple processing method for producing porous ceramics using polysiloxane precursors, Kamiya and Iijima focus on surface modification and characterization of nanomaterials, and Wan et al briefly review the strategy of reducing lattice thermal conductivity of thermoelectric materials and propose new materials for thermoelectric devices. Aubert et al introduce a novel technique of synthesizing composite nanomaterials and Cross and coworkers characterize Pb(Zr,Ti)O3 (PZT) ferroelectric thin films co-doped with Bi and Fe to enhance PZT capacitor ferroelectric properties. These articles are closely related to the global environmental load and energy issues that require solutions in modern ceramics technology. We hope that this focus issue will help advance not only ceramics-related but also other fields of materials science.

  4. Structure and electrical properties of Na1/2Bi1/2TiO3-xK1/2Bi1/2TiO3 lead-free ferroelectric single crystals

    NASA Astrophysics Data System (ADS)

    Zhang, Haiwu; Chen, Chao; Zhao, Xiangyong; Deng, Hao; Ren, Bo; Li, Xiaobing; Luo, Haosu; Li, Shundao

    2015-01-01

    Dielectric, ferroelectric and piezoelectric properties of lead-free Na1/2Bi1/2TiO3-xK1/2Bi1/2TiO3 (NBT-xKBT) ferroelectric single crystals were characterized systematically. With increasing KBT concentration, the remanent polarization and coercive electric field decrease, while the piezoelectric constant and the electromechanical coupling coefficient increase. The evolution of average and local structures as a function of temperature and composition was investigated using in-situ X-ray diffraction and Raman spectroscopy. The structure/property relationship of NBT-xKBT single crystals was discussed in detail.

  5. Core-shell grain structures and ferroelectric properties of Na0.5K0.5NbO3-LiTaO3-BiScO3 piezoelectric ceramics.

    PubMed

    Zhu, Fangyuan; Ward, Michael B; Li, Jing-Feng; Milne, Steven J

    2015-09-01

    Legislation arising from health and environmental concerns has intensified research into finding suitable alternatives to lead-based piezoceramics. Recently, solid solutions based on sodium potassium niobate (K,Na)NbO3 (KNN) have become one of the globally-important lead-free counterparts, due to their favourable dielectric and piezoelectric properties. This data article provides information on the ferroelectric properties and core-shell grain structures for the system, (1-y)[(1-x)Na0.5K0.5NbO3 - xLiTaO3] - yBiScO3 (x=0-0.1, y=0.02, abbreviated as KNN-xLT-2BS). We show elemental analysis with aid of TEM spot-EDX to identify three-type grain-types in the KNN-LT-BS ternary system. Melting behaviour has been assessed using a tube furnace with build-in camera. Details for the ferroelectric properties and core-shell chemical segregation are illustrated. PMID:26217758

  6. Coreshell grain structures and ferroelectric properties of Na0.5K0.5NbO3LiTaO3BiScO3 piezoelectric ceramics

    PubMed Central

    Zhu, Fangyuan; Ward, Michael B.; Li, Jing-Feng; Milne, Steven J.

    2015-01-01

    Legislation arising from health and environmental concerns has intensified research into finding suitable alternatives to lead-based piezoceramics. Recently, solid solutions based on sodium potassium niobate (K,Na)NbO3 (KNN) have become one of the globally-important lead-free counterparts, due to their favourable dielectric and piezoelectric properties. This data article provides information on the ferroelectric properties and coreshell grain structures for the system, (1?y)[(1?x)Na0.5K0.5NbO3 xLiTaO3] yBiScO3 (x=00.1, y=0.02, abbreviated as KNNxLT2BS). We show elemental analysis with aid of TEM spot-EDX to identify three-type grain-types in the KNNLTBS ternary system. Melting behaviour has been assessed using a tube furnace with build-in camera. Details for the ferroelectric properties and coreshell chemical segregation are illustrated. PMID:26217758

  7. Crack extension in piezoelectric materials

    NASA Astrophysics Data System (ADS)

    Park, Seungbae; Sun, Chin-Teh

    1994-05-01

    Closed form solutions for all three modes of fracture for an infinite piezoelectric medium containing a center crack and is subjected to a combined mechanical and electrical loading were obtained using the Stroh formalism. The strain energy release rate was derived and implication to fracture behavior was discussed. Mode I fracture experiments were conducted using compact tension specimens of PZT-4 piezoelectric ceramic. The results indicate that the use of the strain energy release rate as fracture criterion can accurately account for effects of the electric field on the apparent fracture toughness of the material.

  8. Piezoelectric Driver for Incremental Motion

    NASA Technical Reports Server (NTRS)

    Bruman, Joseph R.

    1987-01-01

    Vibrating device containing two piezoelectric ceramic slabs acts as mechanical driver. Eventually substitutes for small continuous or stepping electric motors of slow to moderate speeds. Piezoelectric driver simple in construction, requires no precise dimensions, inexpensive to make, and needs no lubrication. Not damaged by stalling or overloads and safe for use in explosive atmospheres; Motion controllable in micron-size increments, and holds position when power turned off. Potential applications as positioner or mover. Used to position instrument pointers, antennas, or solar panels; to focus lenses; or operate tuners, recording instruments, or valves.

  9. NASA-DoD Lower Process Temperature Lead-Free Solder Project Overview

    NASA Technical Reports Server (NTRS)

    Kessel, Kurt R.

    2014-01-01

    This project is a follow-on effort to the Joint Council on Aging AircraftJoint Group on Pollution Prevention (JCAAJG-PP) Pb-free Solder Project and NASA-DoD Lead-Free Electronics Project which were the first projects to test the reliability of Pb-free solder joints against the requirements of the aerospace and military community. This effort would continue to build on the results from the JCAAJG-PP Lead-Free Solder Project and NASA-DoD Lead-Free Electronics Project while focusing on a particular failure mechanism currently plaguing Pb-free assemblies, pad cratering.The NASA-DoD Lead-Free Electronics Project confirmed that pad cratering is one of the dominant failure modes that occur in various board level reliability tests, especially under dynamic loading. Pad Cratering is a latent defect that may occur during assembly, rework, and post assembly handling and testing.

  10. Effects of Fe2O3 addition on the piezoelectric and the dielectric properties of 0.99Pb(Zr0.53Ti0.47)O3-0.01Bi(Y1- x Fe x )O3 ceramics for energy-harvesting devices

    NASA Astrophysics Data System (ADS)

    Mahmud, Iqbal; Ur, Soon-Chul; Yoon, Man-Soon

    2014-07-01

    The 0.99Pb(Zr0.53Ti0.47)O3-0.01Bi(Y1- x Fe x )O3 [PZT-BYF(x)] (x = 0.0 - 0.6) piezoelectric ceramics have been synthesized by using a modified conventional solid-state method. Initially, the perovskite Pb(Zr0.53Ti0.47)O3 (PZT) and the cubic-phase Bi(Y1- x Fe x )O3 [BYF(x)] were presynthesized and mixed to prepare PZT-BYF(x) ceramic composites. The effects of BYF(x) addition on the phase formation, microstructure, and piezoelectric/dielectric properties were measured as functions of sintering temperature. In addition to these measurements, the piezoelectric voltage constant ( g 33) and the piezoelectric transduction coefficient ( d 33 × g 33) were measured in order to evaluate the essential criteria for an energy-harvesting material. For all the specimens, X-ray diffraction analyses showed a complete solid solution with co-existing tetragonal and rhombohedral perovskite phases. All the ceramics exhibited denser and finer microstructures, which produced a high relative density of ≥ 98%. Scanning electron microscopy (SEM) observations revealed that BYF(x) addition enhanced the sintering density through the formation of a liquid phase. The doping with BYF(x) in the PZT system was found to be effective for maintaining a high Curie temperature of around 377-390 °C. With increasing content of Fe2O3 in the BYF(x) system, the piezoelectric and the dielectric properties were significantly improved. At a sintering temperature of 1170 °C, the piezoelectric and the dielectric properties of PZT-BYF(x) ceramics showed desirable values; this resulted in a significantly higher transduction coefficient. The compositions of PZTBYF(0.1), PZT-BYF(0.2), and PZT-BYF(0.3) showed a considerably lower ɛ 33 T value, but higher d 33 and k p values. Therefore, within the concentration limit of x = 0.1 to 0.3 moles of Fe2O3, the g 33 and the d 33 × g 33 values were improved significantly ( g 33 > 53 × 10-3 Vm/N and d 33 × g 33 > 20000 m2/N). The maximum transduction coefficient of 20167 × 10-15 m2/N was obtained from the composition of PZT-BYF(0.3). The high values of g 33 and d 33 × g 33 make these piezoelectric ceramics potential candidates for applications in energy-harvesting devices.

  11. Lead-free hunting rifle ammunition: product availability, price, effectiveness, and role in global wildlife conservation.

    PubMed

    Thomas, Vernon George

    2013-10-01

    Proposals to end the use of lead hunting ammunition because of the established risks of lead exposure to wildlife and humans are impeded by concerns about the availability, price, and effectiveness of substitutes. The product availability and retail prices of different calibers of lead-free bullets and center-fire rifle ammunition were assessed for ammunition sold in the USA and Europe. Lead-free bullets are made in 35 calibers and 51 rifle cartridge designations. Thirty-seven companies distribute internationally ammunition made with lead-free bullets. There is no major difference in the retail price of equivalent lead-free and lead-core ammunition for most popular calibers. Lead-free ammunition has set bench-mark standards for accuracy, lethality, and safety. Given the demonstrated wide product availability, comparable prices, and the effectiveness of high-quality lead-free ammunition, it is possible to phase out the use of lead hunting ammunition world-wide, based on progressive policy and enforceable legislation. PMID:23288616

  12. Piezoelectric Film.

    ERIC Educational Resources Information Center

    Garrison, Steve

    1992-01-01

    Presents activities that utilize piezoelectric film to familiarize students with fundamental principles of electricity. Describes classroom projects involving chemical sensors, microbalances, microphones, switches, infrared sensors, and power generation. (MDH)

  13. Dielectric/piezoelectric properties and temperature dependence of domain structure evolution in lead free (KNa)NbO single crystal

    NASA Astrophysics Data System (ADS)

    Lin, Dabin; Li, Zhenrong; Zhang, Shujun; Xu, Zhuo; Yao, Xi

    2009-10-01

    (K 0.5Na 0.5)NbO 3 (KNN) single crystals were grown using a high temperature flux method. The dielectric permittivity was measured as a function of temperature for [001]-oriented KNN single crystals. The ferroelectric phase transition temperatures, including the rhombohedral-orthorhombic T, orthorhombic-tetragonal T and tetragonal-cubic TC were found to be located at -149 ∘C, 205 ∘C and 393 ∘C, respectively. The domain structure evolution with an increasing temperature in [001]-oriented KNN single crystal was observed using polarized light microscopy (PLM), where three distinguished changes of the domain structures were found to occur at -150 ∘C, 213 ∘C and 400 ∘C, corresponding to the three phase transition temperatures.

  14. Ferroelectric domain switching kinetics of a lead-free AgNbO3 thin film on glass substrate

    NASA Astrophysics Data System (ADS)

    Ahn, Yoonho; Seo, Jeongdae; Son, Jong Yeog

    2015-12-01

    Lead-free silver niobate (AgNbO3) thin film was deposited on glass substrate by pulsed laser deposition. Ferroelectric properties of the AgNbO3 thin film were investigated. The AgNbO3 thin film capacitor exhibited good ferroelectricity with a remnant polarization of about 15.7 μC/cm2 (2Pr ∼ 31.4 μC/cm2) at room temperature and fast switching behavior within about 130 ns. Triangular grains on the ANO thin film surface were observed by atomic force microscopy (AFM). By using piezoelectric force microscopy (PFM), we investigated ferroelectric domain switching and domain wall motion of the AgNbO3 thin film. From the domain wall speed as a function of applied electric field in the AgNbO3 thin film, activation energy of domain wall motion was derived. Compared to the PbTiO3 thin film reported previously, the AgNbO3 thin film showed faster switching behavior which could be attributed to its lower activation energy for domain wall motion.

  15. High Dielectric, Piezoelectric, Upconversion Photoluminescence and Low-Temperature Sensing Properties in Ba0.7Sr0.3TiO3-BaZr0.2Ti0.8O3:Ho/Yb Ceramics

    NASA Astrophysics Data System (ADS)

    Zuo, Qianghui; Luo, Laihui; Yao, Yongjie

    2016-02-01

    In the present work, we have synthesized pure and Ho/Yb-co-doped 0.5Ba0.7Sr0.3TiO3-0.5BaZr0.2Ti0.8O3 ceramics using a solid-state reaction technique. The prepared pure 0.5Ba0.7Sr0.3TiO3-0.5BaZr0.2Ti0.8O3 ceramics were found in the morphotropic phase boundary region, and exhibit high piezoelectric and dielectric properties. Under a 980-nm excitation, strong green, red and near-infrared (NIR) upconversion (UC) photoluminescence is observed in Ho/Yb-co-doped samples. It is found that the color of UC emission could be tuned by changing the concentration of sensitizer Yb ions in the host matrix. Furthermore, optical temperature sensing properties based on the green and NIR UC emissions of BSZT:0.005Ho/0.01Yb were investigated. Fluorescence intensity ratio (FIR) between green (5F4,5S2) → 5I8 and NIR (5F4,5S2) → 5I7 UC emissions of Ho ions was studied as a function of temperature in the range of 78 K-373 K, and a maximum sensitivity 0.0206 K-1 at 97 K was obtained.

  16. Electrocaloric effect and luminescence properties of lanthanide doped (Na1/2Bi1/2)TiO3 lead free materials

    NASA Astrophysics Data System (ADS)

    Zannen, M.; Lahmar, A.; Asbani, B.; Khemakhem, H.; El Marssi, M.; Kutnjak, Z.; Es Souni, M.

    2015-07-01

    Polycrystalline lead-free Sodium Bismuth Titanate (NBT) ferroelectric ceramics doped with rare earth (RE) element are prepared using solid state reaction method. Optical, ferroelectric, and electrocaloric properties were investigated. The introduction of RE3+ ions in the NBT host lattice shows different light emissions over the wavelength range from visible to near infrared region. The ferroelectric P-E hysteresis loops exhibit an antiferroelectric-like character near room temperature indicating possible existence of a morphotropic phase boundary. The enhanced electrocaloric response was observed in a broad temperature range due to nearly merged phase transitions. Coexistence of optical and electrocaloric properties is very promising for photonics or optoelectronic device applications.

  17. Processing, texture quality, and piezoelectric properties of <001>C textured (1-x)Pb(Mg1/3Nb2/3)TiO3 - xPbTiO3 ceramics

    NASA Astrophysics Data System (ADS)

    Poterala, Stephen F.; Trolier-McKinstry, Susan; Meyer, Richard J.; Messing, Gary L.

    2011-07-01

    This paper describes the link between texture quality and electromechanical properties for <001>C textured, 0.03(Na1/2Bi1/2)TiO3 - 0.97[0.715Pb(Mg1/3Nb2/3)TiO3 - 0.285PbTiO3] (0.03NBT-0.97[PMN-28.5PT]) ceramics with and without Mn-doping. Here, the subscript C denotes pseudocubic indices. Textured ceramics were prepared by templated grain growth of PMN-25PT on platelet-shaped 0.4(Na1/2Bi1/2)TiO3-0.6PbTiO3 (NBT-0.6PT) templates. Texture fractions of f = 0.92 (for undoped (1-x)Pb(Mg1/3Nb2/3)TiO3-xPbTiO3 (PMN-PT)) and f = 0.49 (for Mn-doped PMN-PT) were determined by fitting 002C XRD pole figures to the March-Dollase model, which was modified to account for symmetry-related 200C and 020C reflections. Using resonance methods, the elastic constants cij, sij, piezoelectric constants dij, eij, gij, hij, dielectric constants ɛij, and coupling coefficients kij of textured PMN-PT ceramics were characterized. It was found that the properties of textured PMN-PT approach the single crystal values along the texture axis (<001>C, also the poling axis), but not in transverse directions. In particular, the elastic compliance sE11 (perpendicular to <001>C) approaches an average of the single crystal sE11 and sE11(45°) coefficients, resulting in anomalous -sE12/sE11 ratios of - 0.01 and 0.04 in pure and Mn-doped textured PMN-PT, respectively. The 33-mode properties as measured by resonance-antiresonance methods were d33 = 852 pC/N, k33 = 0.83, ɛ33 = 3500, and mechanical quality factor Qm = 94 for undoped textured ceramics and d33 = 515, k33 = 0.76, ɛ33 = 2200, and Qm = 714 for Mn-doped textured ceramics.

  18. Large piezoelectricity in Pb-free 0.96(K{sub 0.5}Na{sub 0.5}){sub 0.95}Li{sub 0.05}Nb{sub 0.93}Sb{sub 0.07}O{sub 3}−0.04BaZrO{sub 3} ceramic: A perspective from microstructure

    SciTech Connect

    Gao, Jinghui Li, Huiying; Zhong, Lisheng; Li, Shengtao; Hao, Yanshuang; Ren, Shuai Fang, Minxia; Ren, Xiaobing; Kimoto, Takayoshi; Wang, Yu

    2015-02-28

    We employ transmission electron microscopy to explore the reason for large piezoelectricity (d{sub 33}≈400pC/N) in a Pb-free 0.96(K{sub 0.5}Na{sub 0.5}){sub 0.95}Li{sub 0.05}Nb{sub 0.93}Sb{sub 0.07}O{sub 3} −0.04BaZrO{sub 3} ceramic from microstructure. The result shows that the high piezoelectricity corresponds to a miniaturized nanodomain configuration in a domain hierarchy. The nanodomains disappear on heating accompanied by a reduction in d{sub 33} value. Further convergent beam electron diffraction study reveals a coexistence of tetragonal and orthorhombic phase, which indicates that large piezoelectricity of KNLNS{sub 0.07}-BZ may stem from easy polarization rotation due to low polarization anisotropy on the tetragonal-orthorhombic phase boundary.

  19. Two-step sintering of new potassium sodium niobate ceramics: a high d?? and wide sintering temperature range.

    PubMed

    Wu, Jiagang; Wang, Yumei

    2014-09-14

    In this work, the two-step sintering technique is used to realize a high piezoelectric constant (d33) and wide sintering temperature range (T(S)) in the 0.955(K(0.42)Na(0.58))(Nb(0.96)Sb(0.04))O3-0.045(Bi(0.5)K(0.5))(0.90)Zn(0.10)ZrO3 lead-free ceramics. Dense microstructures were developed in the ceramics by two-step sintering. In the T(S) range of 800-1130 C, the rhombohedral-tetragonal phase boundary was well maintained, and these ceramics possess enhanced dielectric, ferroelectric, and piezoelectric properties. It is of great interest to note that a d33 of 323-416 pC/N could be attained in a temperature gap range of 330 C. We believe that the two-step sintering could both widen the sintering temperature and obtain a high d33 for this material system. PMID:25051530

  20. Magnetoelectric properties of lead-free Ni0.93Co0.02Mn0.05Fe1.95O4-Na0.5Bi0.5TiO3 multiferroic composites synthesized by spark plasma sintering

    NASA Astrophysics Data System (ADS)

    Ramana Mudinepalli, Venkata; Song, S.-H.; Li, J.-Q.; Murty, B. S.

    2015-07-01

    Lead-free multiferroic ceramic composites of x Ni0.93Co0.02Mn0.05Fe1.95O4-(1-x) Na0.5Bi0.5TiO3 (x NCMF-(1-x) NBT, where x=0.1, 0.2, 0.3, 0.4 and 0.5 mol fraction) were synthesized by spark plasma sintering (SPS) in conjunction with high-energy ball milling. The phases, dielectric, piezoelectric, ferroelectric, magnetic and magnetoelectric properties of the composites were analyzed. The composites were composed of a mixture of spinel and perovskite phases. All the composite samples exhibited both apparent ferroelectric and ferromagnetic characteristics as well as considerable magnetoelectric (ME) effects. The maximum value of the ME voltage coefficient of the composites was quite high, being up to ~670 mV cm-1 Oe-1 for the 0.5 NCMF-0.5 NBT composite. Overall, the synthesized composites were promising in terms of electrical, magnetic and magnetoelectric properties, indicating that the SPS is a promising method of fabricating ME composite materials.

  1. Generation of Tin(II) Oxide Crystals on Lead-Free Solder Joints in Deionized Water

    NASA Astrophysics Data System (ADS)

    Chang, Hong; Chen, Hongtao; Li, Mingyu; Wang, Ling; Fu, Yonggao

    2009-10-01

    The effect of the anode and cathode on the electrochemical corrosion behavior of lead-free Sn-Ag-Cu and Sn-Ag-Cu-Bi solder joints in deionized water was investigated. Corrosion studies indicate that SnO crystals were generated on the surfaces of all lead-free solder joints. The constituents of the lead-free solder alloys, such as Ag, Cu, and Bi, did not affect the corrosion reaction significantly. In contrast to lead-free solders, PbO x was formed on the surface of the traditional 63Sn-37Pb solder joint in deionized water. A cathode, such as Au or Cu, was necessary for the electrochemical corrosion reaction of solders to occur. The corrosion reaction rate decreased with reduction of the cathode area. The formation mechanism of SnO crystals was essentially a galvanic cell reaction. The anodic reaction of Sn in the lead-free solder joints occurred through solvation by water molecules to form hydrated cations. In the cathodic reaction, oxygen dissolved in the deionized water captures electrons and is deoxidized to hydroxyl at the Au or Cu cathode. By diffusion, the anodic reaction product Sn2+ and the cathodic reaction product OH- meet to form Sn(OH)2, some of which can dehydrate to form more stable SnO· xH2O crystals on the surface of the solder joints. In addition, thermodynamic analysis confirms that the Sn corrosion reaction could occur spontaneously.

  2. Piezoelectric Nanoindentation

    SciTech Connect

    Rar, Andrei; Pharr, George Mathews; Oliver, Warren C.; Karapetian, Edgar; Kalinin, Sergei V

    2006-01-01

    Piezoelectric nanoindentation (PNI) has been developed to quantitatively address electromechanical coupling and pressure-induced dynamic phenomena in ferroelectric materials on the nanoscale. In PNI, an oscillating voltage is applied between the back side of the sample and the indenter tip, and the first harmonic of bias-induced surface displacement at the area of indenter contact is detected. PNI is implemented using a standard nanoindentation system equipped with a continuous stiffness measurement system. The piezoresponse of polycrystalline lead zirconate titanate (PZT) and BaTiO{sub 3} piezoceramics was studied during a standard nanoindentation experiment. For PZT, the response was found to be load independent, in agreement with theoretical predictions. In polycrystalline barium titanate, a load dependence of the piezoresponse was observed. The potential of piezoelectric nanoindentation for studies of phase transitions and local structure-property relations in piezoelectric materials is discussed.

  3. Theoretical and experimental investigations of thickness- stretch modes in 1-3 piezoelectric composites

    NASA Astrophysics Data System (ADS)

    Yang, Z. T.; Zeng, D. P.; He, M.; Wang, H.

    2015-12-01

    Bulk piezoelectric ceramics operating in thickness-stretch (TSt) modes have been widely used in acoustic-related devices. However, the fundamental TSt waves are always coupled with other modes, and the occurrence of these spurious modes in bulk piezoelectric ceramics affects its performance. To suppress the spurious modes, 1-3 piezoelectric composites are promising candidates. However, theoretical modeling of multiphase ceramic composite objects is very complex. In this study, a 1-3 piezoelectric composite sample and a bulk piezoelectric sample are fabricated. The electrical impedance of these two samples are compared. A simple analytical TSt vibration mode from the three dimensional equations of linear piezoelectricity is used to model the performance of 1-3 piezoelectric composites. The theoretical results agree well with the experimental results.

  4. Performance of Lead-Free versus Lead-Based Hunting Ammunition in Ballistic Soap

    PubMed Central

    Gremse, Felix; Krone, Oliver; Thamm, Mirko; Kiessling, Fabian; Tolba, René Hany; Rieger, Siegfried; Gremse, Carl

    2014-01-01

    Background Lead-free hunting bullets are an alternative to lead-containing bullets which cause health risks for humans and endangered scavenging raptors through lead ingestion. However, doubts concerning the effectiveness of lead-free hunting bullets hinder the wide-spread acceptance in the hunting and wildlife management community. Methods We performed terminal ballistic experiments under standardized conditions with ballistic soap as surrogate for game animal tissue to characterize dimensionally stable, partially fragmenting, and deforming lead-free bullets and one commonly used lead-containing bullet. The permanent cavities created in soap blocks are used as a measure for the potential wound damage. The soap blocks were imaged using computed tomography to assess the volume and shape of the cavity and the number of fragments. Shots were performed at different impact speeds, covering a realistic shooting range. Using 3D image segmentation, cavity volume, metal fragment count, deflection angle, and depth of maximum damage were determined. Shots were repeated to investigate the reproducibility of ballistic soap experiments. Results All bullets showed an increasing cavity volume with increasing deposited energy. The dimensionally stable and fragmenting lead-free bullets achieved a constant conversion ratio while the deforming copper and lead-containing bullets showed a ratio, which increases linearly with the total deposited energy. The lead-containing bullet created hundreds of fragments and significantly more fragments than the lead-free bullets. The deflection angle was significantly higher for the dimensionally stable bullet due to its tumbling behavior and was similarly low for the other bullets. The deforming bullets achieved higher reproducibility than the fragmenting and dimensionally stable bullets. Conclusion The deforming lead-free bullet closely resembled the deforming lead-containing bullet in terms of energy conversion, deflection angle, cavity shape, and reproducibility, showing that similar terminal ballistic behavior can be achieved. Furthermore, the volumetric image processing allowed superior analysis compared to methods that involve cutting of the soap blocks. PMID:25029572

  5. Lead-free precussion primer mixes based on metastable interstitial composite (MIC) technology

    DOEpatents

    Dixon, George P.; Martin, Joe A.; Thompson, Don

    1998-01-01

    A lead-free percussion primer composition and a percussion cup containing e composition. The lead-free percussion primer composition is comprised of a mixture of about 45 wt % aluminum powder having an outer coating of aluminum oxide and molybdenum trioxide powder or a mixture of about 50 wt % aluminum powder having an outer coating of aluminum oxide and polytetrafluoroethylene powder. The aluminum powder, molybdenum trioxide powder and polytetrafluoroethylene powder has a particle size of 0.1 .mu.m or less, more preferably a particle size of from about 200-500 angstroms.

  6. Enhanced bipolar fatigue resistance in CaZrO3-modified (K,Na)NbO3 lead-free piezoceramics

    NASA Astrophysics Data System (ADS)

    Yao, Fang-Zhou; Patterson, Eric A.; Wang, Ke; Jo, Wook; Rödel, Jürgen; Li, Jing-Feng

    2014-06-01

    The bipolar fatigue behavior of (K,Na)NbO3 (KNN)-based lead-free piezoceramics was investigated. A comparative analysis demonstrated that CaZrO3-modified KNN ceramics exhibited highly enhanced bipolar fatigue resistance due to the reduced lattice distortion (c/a ratio) and coexistence of orthorhombic and tetragonal phases. The hypothesis was verified by systematical studies of cycle-dependent large and small signal parameters and micro-morphologies. It was identified that mechanical stress induced microstructure damage beneath the electrodes renders the KNN ceramics to be vulnerable to bipolar cycling; while the mild fatigue behavior for CaZrO3-modified ones mainly originates from a thermally reversible domain wall pinning.

  7. High Temperature, High Power Piezoelectric Composite Transducers

    PubMed Central

    Lee, Hyeong Jae; Zhang, Shujun; Bar-Cohen, Yoseph; Sherrit, StewarT.

    2014-01-01

    Piezoelectric composites are a class of functional materials consisting of piezoelectric active materials and non-piezoelectric passive polymers, mechanically attached together to form different connectivities. These composites have several advantages compared to conventional piezoelectric ceramics and polymers, including improved electromechanical properties, mechanical flexibility and the ability to tailor properties by using several different connectivity patterns. These advantages have led to the improvement of overall transducer performance, such as transducer sensitivity and bandwidth, resulting in rapid implementation of piezoelectric composites in medical imaging ultrasounds and other acoustic transducers. Recently, new piezoelectric composite transducers have been developed with optimized composite components that have improved thermal stability and mechanical quality factors, making them promising candidates for high temperature, high power transducer applications, such as therapeutic ultrasound, high power ultrasonic wirebonding, high temperature non-destructive testing, and downhole energy harvesting. This paper will present recent developments of piezoelectric composite technology for high temperature and high power applications. The concerns and limitations of using piezoelectric composites will also be discussed, and the expected future research directions will be outlined. PMID:25111242

  8. High temperature, high power piezoelectric composite transducers.

    PubMed

    Lee, Hyeong Jae; Zhang, Shujun; Bar-Cohen, Yoseph; Sherrit, Stewart

    2014-01-01

    Piezoelectric composites are a class of functional materials consisting of piezoelectric active materials and non-piezoelectric passive polymers, mechanically attached together to form different connectivities. These composites have several advantages compared to conventional piezoelectric ceramics and polymers, including improved electromechanical properties, mechanical flexibility and the ability to tailor properties by using several different connectivity patterns. These advantages have led to the improvement of overall transducer performance, such as transducer sensitivity and bandwidth, resulting in rapid implementation of piezoelectric composites in medical imaging ultrasounds and other acoustic transducers. Recently, new piezoelectric composite transducers have been developed with optimized composite components that have improved thermal stability and mechanical quality factors, making them promising candidates for high temperature, high power transducer applications, such as therapeutic ultrasound, high power ultrasonic wirebonding, high temperature non-destructive testing, and downhole energy harvesting. This paper will present recent developments of piezoelectric composite technology for high temperature and high power applications. The concerns and limitations of using piezoelectric composites will also be discussed, and the expected future research directions will be outlined. PMID:25111242

  9. Multilayer piezoelectric actuators - Structures and reliability

    NASA Astrophysics Data System (ADS)

    Yoshikawa, Shoko; Shrout, Thomas

    1993-04-01

    Four types of internal electrode configuration have been developed for cofired piezoelectric and electrostrictive ceramic multilayer actuators (MLAs) fabricated by means of conventional multilayer ceramic capacitor (MLC) processing. MLC-type electrode structures with slits or gaps have been introduced to solve several problems associated with simpler MLA designs; a novel interdigital line electrode configuration is used which offers large displacement through the excitation of gaps between fine electrode lines, by means of the introduction of a nonuniform field strength.

  10. Electronic Properties of Lead-Free (Ba0.95Ca0.05)(Ti0.92Sn0.08)O3 Piezoceramic Nanofibers by Electrospinning

    NASA Astrophysics Data System (ADS)

    Sahoo, Benudhar; Panda, Prasanta Kumar

    2015-11-01

    Lead-free (Ba0.95Ca0.05)(Ti0.92Sn0.08)O3, (BCTS) piezoceramic nanofibers were prepared by electrospinning acetate precursor solutions in polyvinyl pyrrolidone, followed by calcining at 1150ºC for 2 h. X-ray diffraction of calcined nanofibers confirmed the formation of the BCTS phase and energy dispersive x-ray analysis confirmed the presence of Ca and Sn ions. The scanning electron microscope studies showed cylindrical fibers with a diameter in the range 80-275 nm. The dielectric constant and piezoelectric charge constant ( d 33) were 3485 at 100 Hz, RT and 398 pC/N, respectively.

  11. Piezoelectric constant for binary piezoelectric 0-3 connectivity composites and the effect of mixed connectivity

    NASA Astrophysics Data System (ADS)

    Jayasundere, N.; Smith, B. V.; Dunn, J. R.

    1994-09-01

    An analytic expression is presented for the piezoelectric d constant of a binary piezoelectric 0-3 connectivity composite. The expression is developed under the limiting assumption that the dielectric constant of the ceramic is much greater than the matrix. Predictions made using the theory compare very favorably with available experimental data. A 0-3/1-3 mixed connectivity model is also described for composites in which the average piezoceramic particle size is a significant fraction of the thickness of the composite.

  12. Lead-free solders: issues of toxicity, availability and impacts of extraction

    NASA Technical Reports Server (NTRS)

    Ku, A.; Shapiro, A. A.; Kua, A.; Ogunseitan, O.; Saphores, J. D.; Schoenung, J. M.

    2003-01-01

    This project set out to evaluate the critical issues of toxicity and public health effects, material availability, and the environmental impacts of raw material extraction and metal finishing, with the goal of using environmental impact as a factor in selecting feasible lead-free alloys.

  13. How to Identify Lead Free Certification Marks for Drinking Water System & Plumbing Products

    EPA Science Inventory

    The Reduction of Lead in Drinking Water Act went into effect on January 4, 2014. The Act has reduced the lead content allowed in water system and plumbing products by changing the definition of lead free in Section 1417 of the Safe Drinking Water Act (SDWA) from not more than 8% ...

  14. How to Identify Lead-Free Certification Marks for Drinking Water System & Plumbing Materials

    EPA Science Inventory

    In 2011, Congress passed the Reduction of Lead in Drinking Water Act, which effectively reduces the lead content allowed in material used for potable water plumbing. The Act, which will go into effect on January 4, 2014, changes the definition of lead-free by reducing allowed...

  15. How to Identify Lead-Free Certification Marks for Drinking Water System & Plumbing Materials - Presentation

    EPA Science Inventory

    In 2011, Congress passed the Reduction of Lead in Drinking Water Act, which effectively reduces the lead content allowed in material used for potable water plumbing. The Act, which will go into effect on January 4, 2014, changes the definition of lead-free by reducing allowed...

  16. Joint Lead-Free Solder Test Program for High Reliability Military and Space Applications

    NASA Technical Reports Server (NTRS)

    Brown, Christina

    2004-01-01

    Current and future space and defense systems face potential risks from the continued use of tin-lead solder, including: compliance with current environmental regulations, concerns about potential environmental legislation banning lead-containing products, reduced mission readiness, and component obsolescence with lead surface finishes. For example, the United States Environmental Protection Agency (USEPA) has lowered the Toxic Chemical Release reporting threshold for lead to 100 pounds. Overseas, the Waste Electrical and Electronic Equipment (WEEE) and the Restriction on Hazardous Substances (RoHS) Dicctives in Europe and similar mandates in Japan have instilled concern that a legislative body will prohibit the use of lead in aerospace/military electronics soldering. Any potential banning of lead compounds could reduce the supplier base and adversely affect the readiness of missions led by the National Aeronautics and Space Administration (NASA) and the U.S. Department of Defense (DoD). Before considering lead-free electronics for system upgrades or future designs, however, it is important for the DoD and NASA to know whether lead-free solders can meet their systems' requirements. No single lead-free solder is likely to qualify for all defense and space applications. Therefore, it is important to validate alternative solders for discrete applications. As a result of the need for comprehensive test data on the reliability of lead-free solders, a partnership was formed between the DoD, NASA, and several original equipment manufactures (OEMs) to conduct solder-joint reliability (laboratory) testing of three lead-free solder alloys on newly manufactured and reworked circuit cards to generate performance data for high-reliability (IPC Class 3) applications.

  17. Miniature piezoelectric triaxial accelerometer measures cranial accelerations

    NASA Technical Reports Server (NTRS)

    Deboo, G. J.; Rogallo, V. L.

    1966-01-01

    Tiny triaxial accelerometer whose sensing elements are piezoelectric ceramic beams measures human cranial accelerations when a subject is exposed to a centrifuge or other simulators of g environments. This device could be considered for application in dental, medical, and automotive safety research.

  18. Radial Field Piezoelectric Diaphragms

    NASA Technical Reports Server (NTRS)

    Bryant, R. G.; Effinger, R. T., IV; Copeland, B. M., Jr.

    2002-01-01

    A series of active piezoelectric diaphragms were fabricated and patterned with several geometrically defined Inter-Circulating Electrodes "ICE" and Interdigitated Ring Electrodes "ICE". When a voltage potential is applied to the electrodes, the result is a radially distributed electric field that mechanically strains the piezoceramic along the Z-axis (perpendicular to the applied electric field). Unlike other piezoelectric bender actuators, these Radial Field Diaphragms (RFDs) strain concentrically yet afford high displacements (several times that of the equivalent Unimorph) while maintaining a constant circumference. One of the more intriguing aspects is that the radial strain field reverses itself along the radius of the RFD while the tangential strain remains relatively constant. The result is a Z-deflection that has a conical profile. This paper covers the fabrication and characterization of the 5 cm. (2 in.) diaphragms as a function of poling field strength, ceramic thickness, electrode type and line spacing, as well as the surface topography, the resulting strain field and displacement as a function of applied voltage at low frequencies. The unique features of these RFDs include the ability to be clamped about their perimeter with little or no change in displacement, the environmentally insulated packaging, and a highly repeatable fabrication process that uses commodity materials.

  19. NASA-DoD Lead-Free Electronics Project: Vibration Test

    NASA Technical Reports Server (NTRS)

    Woodrow, Thomas A.

    2010-01-01

    Vibration testing was conducted by Boeing Research and Technology (Seattle) for the NASA-DoD Lead-Free Electronics Solder Project. This project is a follow-on to the Joint Council on Aging Aircraft/Joint Group on Pollution Prevention (JCAA/JG-PP) Lead-Free Solder Project which was the first group to test the reliability of lead-free solder joints against the requirements of the aerospace/miLItary community. Twenty seven test vehicles were subjected to the vibration test conditions (in two batches). The random vibration Power Spectral Density (PSD) input was increased during the test every 60 minutes in an effort to fail as many components as possible within the time allotted for the test. The solder joints on the components were electrically monitored using event detectors and any solder joint failures were recorded on a Labview-based data collection system. The number of test minutes required to fail a given component attached with SnPb solder was then compared to the number of test minutes required to fail the same component attached with lead-free solder. A complete modal analysis was conducted on one test vehicle using a laser vibrometer system which measured velocities, accelerations, and displacements at one . hundred points. The laser vibrometer data was used to determine the frequencies of the major modes of the test vehicle and the shapes of the modes. In addition, laser vibrometer data collected during the vibration test was used to calculate the strains generated by the first mode (using custom software). After completion of the testing, all of the test vehicles were visually inspected and cross sections were made. Broken component leads and other unwanted failure modes were documented.

  20. [Shielding evaluation of lead-free board for diagnostic X-rays].

    PubMed

    Katoh, Yoh; Tsukada, Masaru; Mita, Sogo; Fukushi, Masahiro; Nyui, Yoshiyuki; Abe, Shinji; Kimura, Junichi

    2010-12-20

    For physical foundation data used in the shielding calculation of structural facilities such as a radiation room, there are air kerma transmissions concerning the thickness of shielding objects, and half value layers and tenth value layers concerning a greatly attenuated wide X-ray beam. Accordingly, we evaluated the above-mentioned items with a lead-free board, which is mixed sulfuric acid calcium and barium sulfate with equiponderance for the amount of sulfuric acid calcium included in the usual plasterboard. Permeability in NCRP Report 147 is expressed by 3 parameters, α, β and γ, and shielding objects x. It showed that it corresponds to the measurement point and permeability curve with parameters, α, β and γ obtained by nonlinear regression analysis. Furthermore, we calculated the half value layer and tenth value layer concerning the greatly attenuated wide X-ray beam. The evaluated lead-free board, used in this examination, is useful as the shielding material for the diagnosis X-ray and, moreover, the partition wall materials are hard enough, with a board that is even heavier than the usual plaster board. Besides, the use of lead-free materials is friendly to the general environment. PMID:21282911

  1. Dielectric spectroscopy of Dy2O3 doped (K0.5Na0.5)NbO3 piezoelectric ceramics

    NASA Astrophysics Data System (ADS)

    Mahesh, P.; Subhash, T.; Pamu, D.

    2014-06-01

    We report the dielectric properties of ( K 0.5 Na 0.5 ) NbO 3 ceramics doped with x wt% of Dy 2 O 3 (x= 0.0-1.5 wt%) using the broadband dielectric spectroscopy. The X-ray diffraction studies showed the formation of perovskite structure signifying that Dy 2 O 3 diffuse into the KNN lattice. Samples doped with x > 0.5 wt% exhibit smaller grain size and lower relative densities. The dielectric properties of KNN ceramics doped with Dy 2 O 3 are enhanced by increasing the Dy 3+ content; among the compositions studied, x = 0.5 wt% exhibited the highest dielectric constant and lowest loss at 1MHz over the temperature range of 30°C to 400°C. All the samples exhibit maximum dielectric constant at the Curie temperature (˜ 326°C) and a small peak in the dielectric constant at around 165°C is due to a structural phase transition. At the request of all authors, and by agreement with the Proceedings Editors, a corrected version of this article was published on 19 June 2014. The full text of the Corrigendum is attached to the corrected article PDF file.

  2. Piezoelectric circular ring flexural transducers.

    PubMed

    Aronov, Boris S

    2013-08-01

    An analytical treatment of the piezoelectric ceramic complete ring transducer undergoing flexural vibrations is presented. Conditions for the electromechanical excitation of the flexural vibrations are discussed and it is shown that the fundamental mode of the flexural vibration of a complete ring can be considered as sufficiently dominant over a broad frequency range. Hence, the one-dimensional equivalent electromechanical circuit representation of the transducer is applicable and all the parameters of the equivalent circuit are determined. Possibilities to optimize the effective coupling coefficient of the transducer by changing the extent of the electrodes on the piezoelectric body are considered. It is shown that for effective operation of the flexural ring transducer as a low frequency hydroacoustic projector the opposing quadrants (or three quadrants in case of a planar array configuration) have to be covered with baffles. The radiation impedance and directional factors of the transducers with baffles are considered. Limitations of the acoustical power radiated by the transducers are discussed. PMID:23927101

  3. Controlling the Color of Lead-Free Red Overglaze Enamels and a Process for Preparing High-Quality Red Paints.

    PubMed

    Hashimoto, Hideki; Inada, Hirofumi; Okazaki, Yuki; Takaishi, Taigo; Fujii, Tatsuo; Takada, Jun

    2016-05-01

    Akae porcelain, an artistic Japanese traditional overglaze ceramic typically known for Kakiemon-style ware, has fascinated porcelain lovers around the world for over 400 years because of the graceful red color displayed by akae that matches so well with white porcelain bodies. In this work, we clarified the factors that control the color of akae and those that are conventionally controlled by artisans based on empirical experience. Inspired by a recent particle-design method, we also developed a practical facile process to prepare red paints that yields high-quality akae. Various akae samples were prepared from a combination of lead-free alkali borosilicate glass frits with different particle sizes and hematite powders with differing dispersibilities. Polarized light microscopy, scanning electron microscopy, and transmission electron microscopy analyses indicate that considering only the dispersibility of hematite powders is not sufficient, but the frit-particle size must be controlled to obtain high-quality akae with a high reflectance value for ≥580 nm visible light. In addition, we developed a process for preparing high-quality red paints that uses a large-particle frit powder and a strongly aggregated-hematite powder, both of which are easily obtainable. The red paint composed of frit, hematite, and the solvent is mixed until the paint is drying. By adding more solvent and repeating this process three times, we obtained high-quality akae with a higher reflectance value than for the akae prepared from a frit with submicron-sized particles and weakly aggregated-hematite powder. On the basis of transmission electron microscopic observations, we consider the red paint to consist of a core/shell-like composite structure of frit and hematite, forming a three-dimensional network in the akae glass layer. The good dispersibility of these particles leads to high-quality akae. PMID:27093650

  4. Lead-Free Double-Base Propellant for the 2.75 Inch Rocket Motor

    NASA Technical Reports Server (NTRS)

    Magill, B. T.; Nauflett, G. W.; Furrow, K. W.

    2000-01-01

    The current MK 66 2.75 inch Rocket Motor double-base propellant contains the lead-based ballistic modifier LC-12-15 to achieve the desired plateau and mesa burning rate characteristics. The use of lead compounds poses a concern for the environment and for personal safety due to the metal's toxic nature when introduced into the atmosphere by propellant manufacture, rocket motor firing, and disposal. Copper beta-resorcylate (copper 2,4-di-hydroxy-benzoate) was successfully used in propellant as a simple modifier in the mid 1970's. This and other compounds have also been mixed with lead salts to obtain more beneficial ballistic results. Synthesized complexes of lead and copper compounds soon replaced the mixtures. The complexes incorporate the lead, copper lack of organic liquids, which allows for easier propellant processing. About ten years ago, the Indian Head Division, Naval Surface Warfare Center (NSWC), initiated an effort to develop a lead-free propellant for use in missile systems. Several lead-free propellant candidate formulations were developed. About five years ago, NSWC, in conjunction with Alliant Techsystems, Radford Army Ammunition Plant, continued ballistic modifier investigations. A four component ballistic modifier system without lead for double-base propellants that provide adequate plateau and mesa burn rate characteristics was developed and patented. The ballistic modifier's system contains bismuth subsalicylate, 1.5 percent; copper salicylate, 1.0 percent, copper stannate, 0.77 percent; and carbon black, 0.1 percent. Action time and impulse data obtained through multiple static firings indicate that the new lead-free double-base propellant, while not a match for NOSIH-AA-2, will be a very suitable replacement in the 2.75 inch Rocket Motor. Accelerated aging of the double-base propellant containing the lead-free ballistic modifier showed that it had a much higher rate of stabilizer depletion than the AA-2. A comprehensive study showed that an increased rate of stabilizer depletion occurred in propellants containing monobasic copper salicylate. The study also showed that propellants containing a mixture of bismuth subsalicylate and copper salicylate, had only about one-half the stabilizer depletion rate than those with copper salicylate alone. The copper salicylate catalyzes the decomposition of nitroglycerin, which triggers a chain of events leading to the increased rate of stabilizer depletion. A program has been initiated to coat the ballistic modifier, thus isolating it from the nitroglycerin.

  5. Electrical measurement of a lead-free solder assembly after environmental tests by SEM internal probing

    NASA Astrophysics Data System (ADS)

    Shih, T. I.; Lin, Y. C.; Duh, J. G.; Hsu, Tom; Wu, W. S.

    2007-07-01

    In this study, electrical characterization for lead-free materials in bump technology was developed and joint assemblies were thermally treated under temperature cycling tests. Measurements of sheet resistivity and contact resistance of intermetallic compounds (IMCs) in solder joints were conducted. Quantitative analysis and elemental redistribution of IMCs were obtained by field-emission electron probe microanalyzer. A scanning-electron microscopy internal probing system was introduced to evaluate electrical characteristics in IMCs after thermal treatments. To determine resistivity of IMCs, a novel method incorporating SELA-EM2 and a focused ion beam was developed to prepare the joint sample.

  6. Study of domain structure of poled (K,Na)NbO3 ceramics

    NASA Astrophysics Data System (ADS)

    Qin, Yalin; Zhang, Jialiang; Gao, Yong; Tan, Yongqiang; Wang, Chunlei

    2013-05-01

    Domain structure may greatly affect the dielectric and piezoelectric properties of a ferroelectric ceramic material. However, no investigations on the domain structure of poled (K,Na)NbO3-based ceramics have been reported so far. Since (K0.50Na0.50)NbO3 is the basic composition for the important type of lead-free piezoelectric materials, domain structure of the poled (K0.50Na0.50)NbO3 ceramics with the average grain size of about 8 μm were explored by observing the domain patterns with an acid etching technique in this study. It was found that domain patterns show usually either a single set of parallel domain stripes or a few sets of parallel domain stripes in polycrystalline grains. The average domain widths in different sets of parallel domain stripes vary largely from 150 nm to 750 nm. The intersection angels between two adjacent sets of domain stripes are around 45° or 135°. Two models of domain configuration were proposed to explain those domain patterns that consist of more than two sets of parallel domain stripes. One is built up in the way that the intersection angles between two adjacent sets of domain stripes are acute and consists of 90°-, 60°- and 120°-domain walls. The other one is formed in the way that the intersection angles between two adjacent sets of domain stripes are obtuse and is composed of 180°-, 90°- and 120°-domain walls. Additionally, the change of intersection angle between two adjacent sets of domain stripes with varying the observation plane is discussed.

  7. Analytical analysis of a beam flexural-mode piezoelectric actuator for deformable mirrors

    NASA Astrophysics Data System (ADS)

    Wang, Hairen

    2015-10-01

    A beam flexural-mode piezoelectric bimorph actuator is analyzed based on linear piezoelectricity, and the performance of the actuator is studied. The beam bimorph piezoelectric actuator (BBPA), which is a sandwich compound consisting of a lower and an upper piezoelectric ceramic surface layer and a middle layer made of metal, is driven to flexural deformation. The statistical analytical solution and dynamical solutions from the three-dimensional equations of linear piezoelectricity are derived, and the dependence of the performance upon the physical parameters of the BBPA is evaluated. Numerical results illustrate the strengthened performance achieved by adjusting the geometrical and material parameters of the BBPA.

  8. Nanoscale Insight into Lead-Free BNT-BT-xKNN

    SciTech Connect

    Dittmer, Robert; Jo, Wook; Rödel, Jürgen; Kalinin, Sergei V

    2012-01-01

    Piezoresponse force microscopy (PFM) is used to afford insight into the nanoscale electromechanical behavior of lead-free piezoceramics. Materials based on Bi{sub 1/2}Na{sub 1/2}TiO{sub 3} exhibit high strains mediated by a field-induced phase transition. Using the band excitation technique the initial domain morphology, the poling behavior, the switching behavior, and the time-dependent phase stability in the pseudo-ternary system (1-x)(0.94Bi{sub 1/2}Na{sub 1/2}TiO{sub 3}-0.06BaTiO{sub 3})-xK{sub 0.5}Na{sub 0.5}NbO{sub 3} (0 {le} x {ge} 18 mol%) are revealed. In the base material (x = 0 mol%), macroscopic domains and ferroelectric switching can be induced from the initial relaxor state with sufficiently high electric field, yielding large macroscopic remanent strain and polarization. The addition of KNN increases the threshold field required to induce long range order and decreases the stability thereof. For x = 3 mol% the field-induced domains relax completely, which is also reflected in zero macroscopic remanence. Eventually, no long range order can be induced for x {ge} 3 mol%. This PFM study provides a novel perspective on the interplay between macroscopic and nanoscopic material properties in bulk lead-free piezoceramics.

  9. Study on Dynamic Failure Model of Lead-Free Solders Using Shpb Techniques

    NASA Astrophysics Data System (ADS)

    Niu, Xiaoyan; Yuan, Guozheng; Li, Zhigang; Shu, Xuefeng

    The dynamic compressive properties of 96.3Sn3Ag0.7Cu and 99.3Sn0.7Cu solders were studied by means of a split Hopkinson pressure bar at strain rates ranging from 500 to 2000 s-1. Tests were conducted at room temperature and under uniaxial compressive conditions. Eutectic SnPb solders were used as the reference. From the data of tests, it was found that yield strength and flow stress increased remarkably with the increase of strain rate. On logarithmic scales, the yield strength increased linearly with strain rate. These lead-free solders revealed certain visco-plastic behavior and strain rate sensitivity, which predicted using Johnson-Cook material model. Related parameters in the model were determined from the experiment. Compared with the typical Pb-containing solder Sn63Pb37, these lead-free solders showed some fine properties and could substitute some Pb-containing solder alloys in microelectronic components packaging and interconnects.

  10. SEM/EDS analysis and characterization of gunshot residues from Brazilian lead-free ammunition.

    PubMed

    Martiny, Andrea; Campos, Andrea P C; Sader, Marcia S; Pinto, Andr L

    2008-05-01

    The exposition to heavy metal-rich airborne due to fire practicing has forced to the development of heavy metal-free environmental ammunition primers all over the world. Here we characterize the GSR elements present in the Brazilian lead-free ammunition produced by Companhia Brasileira de Cartuchos (CBC) and commercialized by MagTech in the U.S. and Europe under the name CleanRange centerfire cartridges. Both first and second generations of CleanRange in calibers 9 mm Luger, .40 S&W, .380 AUTO and .38 SPL were analyzed and compared to regular Brazilian CBC ammunition by scanning electron microscopy/energy dispersive spectroscopy. Differences in composition and morphology of GSR particles from the two generations of CleanRange were observed. The first generation ammunition (found in Europe) presented spherical particles, being strontium the only unique element detected. The second generation (found in the U.S.) produced irregular particles composed mostly by potassium, aluminum, silicon and calcium. We can conclude that identification of GSR derived from CBC second generation lead-free ammunition in suspects' hands may be impossible without the addition of a distinct metallic taggant in the primer composition by the manufacturer. PMID:17764860

  11. Assessment of circuit board surface finishes for electronic assembly with lead-free solders

    SciTech Connect

    Ray, U.; Artaki, I.; Finley, D.W.; Wenger, G.M.; Pan, T.; Blair, H.D.; Nicholson, J.M.; Vianco, P.T.

    1996-10-01

    The suitability of various metallic printed wiring board surface finishes was assessed for new technology applications that incorporate assembly with Lead-free solders. The manufacture of a lead-free product necessitates elimination of lead (Pb) from the solder, the circuit board as well as the component lead termination. It is critical however for the selected interconnect Pb-free solder and the corresponding printed wiring board (PWB) and component lead finishes to be mutually compatible. Baseline compatibility of select Pb-free solders with Pb containing PWB surface finish and components was assessed. This was followed by examining the compatibility of the commercially available CASTIN{trademark} (SnAgCuSb) Pb-free solder with a series of PWB metallic finishes: Ni/Au, Ni/Pd, and Pd/Cu. The compatibility was assessed with respect to assembly performance, solder joint integrity and long term attachment reliability. Solder joint integrity and mechanical behavior of representative 50 mil pitch 20I/O SOICs was determined before and after thermal stress. Mechanical pull test studies demonstrated that the strength of SnAgCuSb solder interconnections is notably greater than that of SnPb interconnections.

  12. Design and characterization of piezoelectric ultrasonic motors

    NASA Astrophysics Data System (ADS)

    Yener, Serra

    This thesis presents modeling and prototype fabrication and characterization of new types of piezoelectric ultrasonic micromotors. Our approach in designing these piezoelectric motors was: (i) to simplify the structure including the poling configuration of piezoelectric elements used in the stator and (ii) to reduce the number of components in order to decrease the cost and enhance the driving reliability. There are two different types of piezoelectric motors designed throughout this research. The first of these designs consists of a metal tube, on which two piezoelectric ceramic plates poled in thickness direction, were bonded. Two orthogonal bending modes of the hollow cylinder were superimposed resulting in a rotational vibration. Since the structure and poling configuration of the active piezoelectric elements used in the stator are simple, this motor structure is very suitable for miniaturization. Moreover, a single driving source can excite two bending modes at the same time, thus generate a wobble motion. Three types of prototypes are included in this design. The piezoelectric stator structure is the same for all. However, the dimensions of the motors are reduced by almost 50 percent. Starting with a 10 mm long stator, we reached to 4 mm in the last prototype. The initial diameter was 2.4 mm, which was reduced to 1.6 mm. In the final design, the rotor part of the motor was changed resulting in the reduction in the number of components. In terms of driving circuit, a single driving source was enough to run the motors and a conventional switching power supply type resonant L-C circuit was used. A simple motor structure with a simple driving circuit were combined successfully and fabricated inexpensively. The second design is a shear type piezoelectric linear motor. The behavior of a single rectangular piezoelectric shear plate was analyzed and after optimizing the dimensions and the mode characteristics, a prototype was fabricated. The prototype consists of one layer of ceramic and a brass teeth-like layer bonded on it. The displacement was amplified with the metal layer, the teeth of which were placed on the points of in-phase motion. The targeted application area is paper-feeding mechanism. In terms of application areas for the first design, a gas valve system and a micro vehicle were constructed. In addition, a new optical coherence tomography endoscope by utilizing the piezoelectric micromotor was designed. Finally, the prototype motor was integrated inside the camera of a cell phone to drive the zoom mechanism.

  13. First principles investigations of structural, elastic, dielectric and piezoelectric properties of { Ba,Sr,Pb } TiO3, { Ba,Sr,Pb } ZrO3 and { Ba,Sr,Pb } { Zr,Ti } O3 ceramics

    NASA Astrophysics Data System (ADS)

    Akgenc, Berna; Tasseven, Cetin; Cagin, Tahir

    2015-03-01

    We use first-principle density-functional study of structural, anisotropic mechanical, dielectric and piezoelectric properties of {Ba,Sr,Pb}TiO3, {Ba,Sr,Pb}ZrO3 and {Ba,Sr,Pb}{Zr,Ti}O3 alloys in cubic perovskite structures at zero temperature. Because there is significant interest in finding new piezoelectrics that do not contain toxic elements such as lead. In this study, we compare piezoelectric response of those alloys to synthesize outstanding piezoelectric materials. In perovskite structures, the spontaneous polarization is due to enormous values of Born effective charges computed by linear response within density functional perturbation theory, which are much larger than predicted nominal charge. We deeply investigated the effects of composition, order and site defects structure on piezoelectric constants.

  14. Enhanced piezoelectric performance of composite sol-gel thick films evaluated using piezoresponse force microscopy

    NASA Astrophysics Data System (ADS)

    Liu, Yuanming; Lam, Kwok Ho; Kirk Shung, K.; Li, Jiangyu; Zhou, Qifa

    2013-05-01

    Conventional composite sol-gel method has been modified to enhance the piezoelectric performance of ceramic thick films. Lead zirconate titanate (PZT) and lead magnesium niobate-lead titanate (PMN-PT) thick films were fabricated using the modified sol-gel method for ultrasonic transducer applications. In this work, piezoresponse force microscopy was employed to evaluate the piezoelectric characteristics of PZT and PMN-PT composite sol-gel thick films. The images of the piezoelectric response and the strain-electric field hysteresis loop behavior were measured. The effective piezoelectric coefficient (d33,eff) of the films was determined from the measured loop data. It was found that the effective local piezoelectric coefficient of both PZT and PMN-PT composite films is comparable to that of their bulk ceramics. The promising results suggest that the modified composite sol-gel method is a promising way to prepare the high-quality, crack-free ceramic thick films.

  15. Enhanced piezoelectric performance of composite sol-gel thick films evaluated using piezoresponse force microscopy.

    PubMed

    Liu, Yuanming; Lam, Kwok Ho; Kirk Shung, K; Li, Jiangyu; Zhou, Qifa

    2013-05-14

    Conventional composite sol-gel method has been modified to enhance the piezoelectric performance of ceramic thick films. Lead zirconate titanate (PZT) and lead magnesium niobate-lead titanate (PMN-PT) thick films were fabricated using the modified sol-gel method for ultrasonic transducer applications. In this work, piezoresponse force microscopy was employed to evaluate the piezoelectric characteristics of PZT and PMN-PT composite sol-gel thick films. The images of the piezoelectric response and the strain-electric field hysteresis loop behavior were measured. The effective piezoelectric coefficient (d33,eff) of the films was determined from the measured loop data. It was found that the effective local piezoelectric coefficient of both PZT and PMN-PT composite films is comparable to that of their bulk ceramics. The promising results suggest that the modified composite sol-gel method is a promising way to prepare the high-quality, crack-free ceramic thick films. PMID:23798771

  16. Green piezoelectric for autonomous smart textile

    NASA Astrophysics Data System (ADS)

    Lemaire, E.; Borsa, C. J.; Briand, D.

    2015-12-01

    In this work, the fabrication of Rochelle salt based piezoelectric textiles are shown. Structures composed of fibers and Rochelle salt are easily produced using green processes. Both manufacturing and the material itself are really efficient in terms of environmental impact, considering the fabrication processes and the material resources involved. Additionally Rochelle salt is biocompatible. In this green paradigm, active sensing or actuating textiles are developed. Thus processing method and piezoelectric properties have been studied: (1) pure crystals are used as acoustic actuator, (2) fabrication of the textile-based composite is detailed, (3) converse effective d33 is evaluated and compared to lead zirconate titanate ceramic. The utility of textile-based piezoelectric merits its use in a wide array of applications.

  17. Electromigration induced failure on lead-free micro bumps in three-dimensional integrated circuits packaging

    NASA Astrophysics Data System (ADS)

    Ouyang, Fan-Yi; Hsu, Hao; Su, Yu-Ping; Chang, Tao-Chih

    2012-07-01

    We report electromigration induced failure on lead-free micro bumps in three-dimensional integrated circuits samples with chip on chip configuration. Compared to flip chip solder joints, micro bumps of chip-on-chip samples exhibit better electromigration resistance and are able to withstand a higher current density. No exhibited electromigration-induced failure was observed when current density was below 2 104 A/cm2. A threshold current density to trigger electromigration in chip-on-chip samples was found to be 3.43 104 A/cm2. When current density was higher than 7.5 104 A/cm2 at an ambient temperature of 150 C, no void propagation through whole bump opening was found; instead, electromigration induced voids were observed at the cathode side of Al trace.

  18. KNN/BNT Composite Lead-Free Films for High-Frequency Ultrasonic Transducer Applications

    PubMed Central

    Lau, Sien Ting; Ji, Hong Fen; Li, Xiang; Ren, Wei; Zhou, Qifa; Shung, K. Kirk

    2011-01-01

    Lead-free K0.5Na0.5NbO3/Bi0.5Na0.5TiO3 (KNN/BNT) films have been fabricated by a composite sol-gel technique. Crystalline KNN fine powder was dispersed in the BNT precursor solution to form a composite slurry which was then spin-coated onto a platinum-buffered Si substrate. Repeated layering and vacuum infiltration were applied to produce 5-μm-thick dense composite film. By optimizing the sintering temperature, the films exhibited good dielectric and ferroelectric properties comparable to PZT films. A 193-MHz high-frequency ultrasonic transducer fabricated from this composite film showed a −6-dB bandwidth of approximately 34%. A tungsten wire phantom was imaged to demonstrate the capability of the transducer. PMID:21244994

  19. Effect of surface oxide on the melting behavior of lead-free solder nanowires and nanorods

    NASA Astrophysics Data System (ADS)

    Gao, Fan; Rajathurai, Karunaharan; Cui, Qingzhou; Zhou, Guangwen; NkengforAcha, Irene; Gu, Zhiyong

    2012-07-01

    Lead-free nanosolders have shown promise in nanowire and nanoelectronics assembly. Among various important parameters, melting is the most fundamental property affecting the assembly process. Here we report that the melting behavior of tin and tin/silver nanowires and nanorods can be significantly affected by the surface oxide of nanosolders. By controlling the nanosolder reflow atmosphere using a flux, the surface oxide of the nanowires/nanorods can be effectively removed and complete nanosolder melting can be achieved. The complete melting of the nanosolders leads to the formation of nanoscale to microscale spherical solder balls, followed by Ostwald ripening phenomenon. The contact angle of the microscale solder balls formed on Si substrate was measured by direct electron microscopic imaging. These results provide new insights into micro- and nanoscale phase transition and liquid droplet coalescence from nanowires/nanorods to spheroids, and are relevant to nanoscale assembly and smaller ball grid array formation.

  20. Analysis of lead free tin-silver-copper and tin-lead solder wetting reactions

    NASA Astrophysics Data System (ADS)

    Anson, Scott J.

    Lead free electronics soldering is driven by a combination of health and environmental concerns, international legislation and marketing pressure by lead free electronics manufacturing competitors. Since July 1, 2006, companies that do not comply with the European Union legislation are not able to sell circuit assemblies with lead solder in the European Union. China has developed its own regulations, based on the European Union documents with a compliance date of March 1, 2007. Extensive testing by the electronics community has determined that the Sn - Ag - Cu (SAC) family of alloys is the preferred choice for lead free Surface Mount Technology (SMT) soldering. The 96.5Sn/3.0Ag/0.5Cu alloy was used in this study. Lead free soldering requires an increase in reflow peak temperatures which further aggravates component moisture sensitivity risks and thereby decreases assembly yield. Prior research has revealed an enhanced solder spreading phenomena at lower peak temperature and shorter time above liquidus with 63Sn/37Pb solder. This current research investigated solder wetting reactions in 63Sn/37Pb and 96.5Sn/3.0Ag/0.5Cu (SAC305) using materials and manufacturing systems that are industry relevant. The objective was to advance the knowledge base of metal wetting while developing a reflow assembly process that minimized the component defect rates. The components are damaged during reflow by popcorn delamination, which is the result of moisture absorption and subsequent rapid evaporation. A classical Design Of Experiments (DOE) approach was used, with wetted area as the response variable. Outside of the DOE, substrate dissolution depth, and substrate surface new phase formation (reaction product) distance from the triple line (solder wetting front) and reaction product thickness in the solder joint (under the solder) were also analyzed. The samples were analyzed for correlation of reflow peak temperature, reflow Time Above Liquidus (TAL), wetted area, reaction product distance from the triple line, substrate dissolution depth, triple line ridge (substrate protrusion into the molten solder) formation and reaction product thickness in the solder joint. The general results are (1) an improved understanding of 63Sn/37Pb and 96.5Sn/3.0Ag/0.5Cu WT% solder wetting reactions, (2) reduced 63Sn/37Pb and SAC reflow peak temperatures, and thereby reduced risk of moisture sensitivity damage to components. The significance of these results are (1) enhanced applied understanding of the complexity of molten metal wetting a substrate and (2) enhanced assembly yield due to minimal aggravation of component moisture sensitivity. The uniqueness of this research is that it utilized a holistic Systems Science approach which provided a combined microscopic (substrate and molten metal reactions) and macroscopic (wetted area) analysis of metal wetting using materials and processes that were directly relevant to electronics manufacturing.

  1. Salient features, response and operation of Lead-Free Gulmarg Neutron Monitor

    NASA Astrophysics Data System (ADS)

    Mufti, S.; Chatterjee, S.; Ishtiaq, P. M.; Darzi, M. A.; Mir, T. A.; Shah, G. N.

    2016-03-01

    Lead-Free Gulmarg Neutron Monitor (LFGNM) provides continuous ground level intensity measurements of atmospheric secondary neutrons produced in interactions of primary cosmic rays with the Earth's constituent atmosphere. We report the LFGNM detector salient features and simulation of its energy response for 10-11 MeV to 104 MeV energy incident neutrons using the FLUKA Monte Carlo package. An empirical calibration of the LFGNM detector carried out with a Pu-Be neutron source for maximising its few MeV neutron counting sensitivity is also presented. As an illustration of its functionality a single representative transient solar modulation event recorded by LFGNM depicting Forbush decrease in integrated neutron data for which the geospace consequences are well known is also presented. Performance of LFGNM under actual observation conditions for effectively responding to transient solar modulation is seen to compare well with other world-wide conventional neutron monitors.

  2. Dielectric Dispersion, Diffuse Phase Transition, and Electrical Properties of BCT-BZT Ceramics Sintered at a Low-Temperature

    NASA Astrophysics Data System (ADS)

    Tian, Yongshang; Gong, Yansheng; Meng, Dawei; Li, Yuanjian; Kuang, Boya

    2015-08-01

    Lead-free ceramics 0.50Ba0.9Ca0.1TiO3-0.50BaTi1- x Zr x O3 (BCT-BZT) were prepared via sintering BCT and BZT nanoparticles, which were synthesized using a modified Pechini polymeric precursor method, at a low temperature of 1260°C. The relative densities of the ceramics prepared with different zirconium contents ( x) were all above 95.3%, reaching a maximum of 97% when x = 0.08. X-ray diffraction results confirmed the onset of phase transformation from orthorhombic to rhombohedral symmetry with increasing zirconium contents, and the polymorphic phase transition was observed at x = 0.10. The dielectric dispersion, diffuse phase transition (DPT), and relaxor-like ferroelectric characteristics as a function of zirconium content were thoroughly studied. Optimum physical properties, remnant polarization ( P r) = 16.4 μC/cm2, piezoelectric constant ( d 33) = ~240 pC/N, and electromechanical coupling factor ( k p) = 0.22, were obtained at x = 0.10. The findings of the current DPT behavior study of BCT-BZT ceramics are believed to be insightful to the development of ferroelectric materials.

  3. Assessment of the Radiation Attenuation Properties of Several Lead Free Composites by Monte Carlo Simulation

    PubMed Central

    Kazempour, M.; Saeedimoghadam, M.; Shekoohi Shooli, F.; Shokrpour, N.

    2015-01-01

    Background: In diagnostic radiology lead apron, are usually used to protect patients and radiology staff against ionizing radiation. Lead apron is a desirable shield due to high absorption and effective attenuation of x-ray photons in the diagnostic radiology range. Objective: Although lead aprons have good radiation protection properties, in recent years, researchers have been looking for alternative materials to be used instead of lead apron because of some problems derived from lead-content of aprons. Because of its lead-content, these radiation protection garments are so heavy and uncomfortable for the staff to wear, particularly in long-time uses. In addition, lead is a toxic element and its disposal is associated with environmental and human-health hazards. Method: In this study, several new combinations of lead free materials ((W-Si), (W-Sn-Ba-EPVC ), (W-Sn-Cd-EPVC)) have been investigated in the energy range of diagnostic radiology in two geometries: narrow and broad beam. Geometries of the radiation attenuation characteristics of these materials was assessed in 40, 60, 90 and 120 kVp and the results compared with those of some lead-containing materials ((Pb-Si), (Pb-EPVC)). Results: Lead shields still provide better protection in low energies (below 40 kVp). Combination of W-Sn-Cd-EPVC has shown the best radiation attenuation features in 60 and 90 kVp and the composition of (W-Sn-Ba-EPVC) represents the best attenuation in 120 kVp, even better than previously mentioned lead- containing composites. Conclusion: Lead free shields are completely effective for protection against X-ray energies in the range of 60 to 120 kVp. PMID:26157732

  4. A novel method for direct solder bump pull testing using lead-free solders

    NASA Astrophysics Data System (ADS)

    Turner, Gregory Alan

    This thesis focuses on the design, fabrication, and evaluation of a new method for testing the adhesion strength of lead-free solders, named the Isotraction Bump Pull method (IBP). In order to develop a direct solder joint-strength testing method that did not require customization for different solder types, bump sizes, specific equipment, or trial-and-error, a combination of two widely used and accepted standards was created. First, solder bumps were made from three types of lead free solder were generated on untreated copper PCB substrates using an in-house fabricated solder bump-on-demand generator, Following this, the newly developed method made use of a polymer epoxy to encapsulate the solder bumps that could then be tested under tension using a high precision universal vertical load machine. The tests produced repeatable and predictable results for each of the three alloys tested that were in agreement with the relative behavior of the same alloys using other testing methods in the literature. The median peak stress at failure for the three solders tested were 2020.52 psi, 940.57 psi, and 2781.0 psi, and were within one standard deviation of the of all data collected for each solder. The assumptions in this work that brittle fracture occurred through the Intermetallic Compound layer (IMC) were validated with the use of Energy-Dispersive X-Ray Spectrometry and high magnification of the fractured surface of both newly exposed sides of the test specimens. Following this, an examination of the process to apply the results from the tensile tests into standard material science equations for the fracture of the systems was performed..

  5. Effects of PbO-B2O3 Glass Doping on the Sintering Temperature and Piezoelectric Properties of 0.35Pb (Ni1/3Nb2/3)O3-0.65Pb(Zr0.41Ti0.59)O3 Ceramics

    NASA Astrophysics Data System (ADS)

    Yi, Jinqiao; Shen, Meng; Liu, Sisi; Jiang, Shenglin

    2015-12-01

    0.35Pb(Ni1/3Nb2/3)O3-0.65Pb(Zr0.41Ti0.59)O3 (PNN-PZT) ceramics doped with 0.5PbO-0.5B2O3 glass have been synthesized by the conventional solid-state sintering technique. The effects of 0.5PbO-0.5B2O3 glass on the sintering temperature and piezoelectric properties of PNN-PZT ceramics were studied. The results indicated that the sintering temperature of PNN-PZT was significantly reduced due to the incorporation of 0.5PbO-0.5B2O3 glass dopant. When the content of 0.5PbO-0.5B2O3 glass was 0.5 wt.%, the sintering temperature of PNN-PZT was observed to reduce from above 1200°C to 920°C while the samples maintained high density (7.91 g/cm3), excellent piezoelectric constant ( d 33 = 479 pC/N), large electromechanical coupling coefficient ( K p = 0.55), and relatively low electromechanical quality factor ( Q m = 79). Moreover, large dielectric constant ( ɛ 33 T / ɛ 0 = 2904) and low dielectric loss (tan δ = 0.0166) were obtained in this work.

  6. Piezoelectric thin films: an integrated review of transducers and energy harvesting

    NASA Astrophysics Data System (ADS)

    Khan, Asif; Abas, Zafar; Kim, Heung Soo; Oh, Il-Kwon

    2016-05-01

    Piezoelectric thin films offer a number of advantages in various applications, such as high energy density harvesters, a wide dynamic range, and high sensitivity sensors, as well as large displacement and low power consumption actuators. This review covers the available material forms and applications of piezoelectric thin films: lead zirconate titanate (PZT)-based thin films, lead-free piezoelectric thin films, piezopolymer films, cellulose-based electroactive paper (EAPap), and many other thin films used for electromechanical transduction. The electromechanical properties and performances of piezoelectric films are compared and their suitability for particular applications are reported. The key ideas of piezoelectric thin films are reviewed and discussed for sensory and actuation systems, energy harvesting, and medical and acoustic transducers. In the last section, an insight into the future outlook and possibilities for thin film-based devices and their integration into real-world applications is presented.

  7. Piezoelectric wind generator

    SciTech Connect

    Schmidt, V. H.

    1985-08-20

    An electric power generator used a piezoelectric transducer mounted on a resilient blade which in turn is mounted on an independently flexible support member. Fluid flow against the blade causes bending stresses in the piezoelectric polymer which produces electric power.

  8. [Study on the performance of piezoelectric micro pump for insulin injection].

    PubMed

    Zhang, Zhijing; Wang, Wei; Chen, Xinyuan

    2015-01-01

    In terms of performance of piezoelectric micro pump, this paper explores the piezoelectric ceramic plate in different wave driven micro pump flow rate. The conclusion is that the square wave voltage gets the biggest micro pump velocity. The velocity and pressure of the micro pump is almost linear relationship, and having nothing to do with the different inner diameter pipes. The piezoelectric micro pump's stability is not good and exists attenuation. PMID:26027300

  9. Evaluation of Mechanical Losses in Piezoelectric Plates using Genetic algorithm

    NASA Astrophysics Data System (ADS)

    Arnold, F. J.; Gonçalves, M. S.; Massaro, F. R.; Martins, P. S.

    Numerical methods are used for the characterization of piezoelectric ceramics. A procedure based on genetic algorithm is applied to find the physical coefficients and mechanical losses. The coefficients are estimated from a minimum scoring of cost function. Electric impedances are calculated from Mason's model including mechanical losses constant and dependent on frequency as a linear function. The results show that the electric impedance percentage error in the investigated interval of frequencies decreases when mechanical losses depending on frequency are inserted in the model. A more accurate characterization of the piezoelectric ceramics mechanical losses should be considered as frequency dependent.

  10. Challenges and New Trends for Piezoelectric Actuators

    NASA Technical Reports Server (NTRS)

    Sehirlioglu, Alp

    2008-01-01

    BiScO3-PbTiO3 ceramics with TC greater than 400 C has been successfully processed. Despite the increase in TC, excess Pb addition increases both the bulk conductivity and the grain boundary contribution to conductivity at elevated temperatures. Conductivity at elevated temperatures, that limits the operating temperature for actuators, has been greatly reduced by excess Bi additions. Excess Bi doping improves poling conditions resulting in enhanced piezoelectric coefficient (d(sub 33) = 408 pC/N).

  11. On the research of lead-free material challengers for PZT replacement

    NASA Astrophysics Data System (ADS)

    Fasquelle, D.; Mascot, M.; Carru, J. C.

    2012-09-01

    This paper reports a study of Ba0.9Sr0.1TiO3 and BaTi0.98Sn0.02O3 thin films elaborated by a sol-gel route and deposited on Pt/Ti/SiO2/Si substrates. The annealing temperatures were 750 °C, 850 °C and 950 °C. An increase of the average size of grains was observed, from 60 nm at 750 °C to 110 nm at 950 °C and from 70 nm at 750 °C to 150 nm at 950 °C, for BST and BTS respectively, as well as an increase of the dielectric constant and remnant polarization. We have also shown that there are benefits for electrical properties to decrease the annealing time. Despite its non-significant piezoelectric and ferroelectric properties, BTS gives good dielectric properties. Under our optimized annealing conditions, we gave the evidence that ferroelectric BST is a good challenger to replace PZT in various applications, except in piezoelectrics, as the electrical properties measured on our thin films were particularly significant for applications in electronic devices.

  12. "Mighty Worm" Piezoelectric Actuator

    NASA Technical Reports Server (NTRS)

    Bamford, Robert M.; Wada, Ben K.; Moore, Donald M.

    1994-01-01

    "Mighty Worm" piezoelectric actuator used as adjustable-length structural member, active vibrator or vibration suppressor, and acts as simple (fixed-length) structural member when inactive. Load force not applied to piezoelectric element in simple-structural-member mode. Piezoelectric element removed from load path when not in use.

  13. Piezoelectric drive circuit

    DOEpatents

    Treu, Jr., Charles A.

    1999-08-31

    A piezoelectric motor drive circuit is provided which utilizes the piezoelectric elements as oscillators and a Meacham half-bridge approach to develop feedback from the motor ground circuit to produce a signal to drive amplifiers to power the motor. The circuit automatically compensates for shifts in harmonic frequency of the piezoelectric elements due to pressure and temperature changes.

  14. Piezoelectric drive circuit

    DOEpatents

    Treu, C.A. Jr.

    1999-08-31

    A piezoelectric motor drive circuit is provided which utilizes the piezoelectric elements as oscillators and a Meacham half-bridge approach to develop feedback from the motor ground circuit to produce a signal to drive amplifiers to power the motor. The circuit automatically compensates for shifts in harmonic frequency of the piezoelectric elements due to pressure and temperature changes. 7 figs.

  15. Integration of lead-free ferroelectric on HfO2/Si (100) for high performance non-volatile memory applications.

    PubMed

    Kundu, Souvik; Maurya, Deepam; Clavel, Michael; Zhou, Yuan; Halder, Nripendra N; Hudait, Mantu K; Banerji, Pallab; Priya, Shashank

    2015-01-01

    We introduce a novel lead-free ferroelectric thin film (1-x)BaTiO3-xBa(Cu1/3Nb2/3)O3 (x = 0.025) (BT-BCN) integrated on to HfO2 buffered Si for non-volatile memory (NVM) applications. Piezoelectric force microscopy (PFM), x-ray diffraction, and high resolution transmission electron microscopy were employed to establish the ferroelectricity in BT-BCN thin films. PFM study reveals that the domains reversal occurs with 180° phase change by applying external voltage, demonstrating its effectiveness for NVM device applications. X-ray photoelectron microscopy was used to investigate the band alignments between atomic layer deposited HfO2 and pulsed laser deposited BT-BCN films. Programming and erasing operations were explained on the basis of band-alignments. The structure offers large memory window, low leakage current, and high and low capacitance values that were easily distinguishable even after ~10(6) s, indicating strong charge storage potential. This study explains a new approach towards the realization of ferroelectric based memory devices integrated on Si platform and also opens up a new possibility to embed the system within current complementary metal-oxide-semiconductor processing technology. PMID:25683062

  16. Integration of lead-free ferroelectric on HfO2/Si (100) for high performance non-volatile memory applications

    PubMed Central

    Kundu, Souvik; Maurya, Deepam; Clavel, Michael; Zhou, Yuan; Halder, Nripendra N.; Hudait, Mantu K.; Banerji, Pallab; Priya, Shashank

    2015-01-01

    We introduce a novel lead-free ferroelectric thin film (1-x)BaTiO3-xBa(Cu1/3Nb2/3)O3 (x = 0.025) (BT-BCN) integrated on to HfO2 buffered Si for non-volatile memory (NVM) applications. Piezoelectric force microscopy (PFM), x-ray diffraction, and high resolution transmission electron microscopy were employed to establish the ferroelectricity in BT-BCN thin films. PFM study reveals that the domains reversal occurs with 180° phase change by applying external voltage, demonstrating its effectiveness for NVM device applications. X-ray photoelectron microscopy was used to investigate the band alignments between atomic layer deposited HfO2 and pulsed laser deposited BT-BCN films. Programming and erasing operations were explained on the basis of band-alignments. The structure offers large memory window, low leakage current, and high and low capacitance values that were easily distinguishable even after ~106 s, indicating strong charge storage potential. This study explains a new approach towards the realization of ferroelectric based memory devices integrated on Si platform and also opens up a new possibility to embed the system within current complementary metal-oxide-semiconductor processing technology. PMID:25683062

  17. Characterization of tin crystal orientation evolution during thermal cycling in lead-free solder joints

    NASA Astrophysics Data System (ADS)

    Zhou, Bite

    To address the long term reliability of lead-free solder joints in electronic devices during thermal cycling, the fundamental understanding of deformation mechanisms was studied using polarized light optical microscopy (PLM), electron backscatter diffraction (EBSD) in scanning electron microscopy (SEM), and synchrotron X-ray diffraction (XRD). Near-eutectic Sn-3.0(wt %) Ag-0.5(wt %) Cu (SAC305) lead-free solder joints were assessed in three different package designs: low-strain plastic ball grid array (PBGA), medium-strain fine-pitch ball grid array (BGA), and high-strain wafer-level-chip-scale package (WLCSP). The effect of microstructure evolution on solder failure is correlated with dislocation slip activities. The major failure mode in lead-free solder joints during thermal cycling that causes the electrical failure of the device is cracking in the bulk Sn near the Si chip/solder interface. Microstructure and Sn grain orientation evolution usually precedes crack development. A combined approach of both statistical analysis of a large number of solder joints, and detailed studies of individual solder balls was used to investigate the causes of fracture. Sn crystal orientation evolution and its effect on deformation was characterized in solder joints with different thermal histories, and compared with those from other package designs with different effective strain levels. The relationship between the initial dominant and localized recrystallized Sn grain orientations on crack development was investigated. It is found that in the low-strain package design, cracking is strongly correlated with Sn grain orientations with the [001] direction (c-axis) nearly aligned with the chip/solder interface. But no cracks were observed in solder balls with dominant orientations that have the c-axis normal to the interface plane. In higher-strain packages, however, cracking occurred in a variety of Sn grain orientations, and even solder balls with dominant orientations that are resistant to fracture in the low-strain package design cracked. Nevertheless, at the early stage of deformation in WLCSP samples, more dramatic plastic deformation and damage was observed in a row of solder balls with similar c-axis orientations (with the [001] direction nearly aligned with the interface plane). Microstructure evolution preceding crack propagation is apparent in all package designs. Both continuous and discontinuous recrystallization processes were observed in solder joints after thermal cycling. More significant microstructure evolution and recrystallization occurred in higher strain package designs. Statistical analysis reveals that there is an increase in the number of high energy high angle grain boundaries and a decrease of low energy low angle and twin boundaries during thermal cycling. Crack propagation was facilitated by the high angle random boundaries developed during recrystallization, whereas the twin boundaries (with near 60° misorientation about the Sn [100] axis) were more resistant to cracking. The relative ease of the deformation of different Sn grain orientations also influenced crack development. Crack propagation was impeded by the hard orientations (with c -axis normal to the interface) that developed during continuous recrystallization. The gradual lattice rotation during the continuous recrystallization process is correlated with dislocation slip on facile slip systems. Local concentration of elastic strain and orientation gradients inside a continuously recrystallized grain are correlated with slip activities, and locally recovered regions may become nucleation sites for the primary recrystallization upon further straining.

  18. Multilayer modal actuator-based piezoelectric transformers.

    PubMed

    Huang, Yao-Tien; Wu, Wen-Jong; Wang, Yen-Chieh; Lee, Chih-Kung

    2007-02-01

    An innovative, multilayer piezoelectric transformer equipped with a full modal filtering input electrode is reported herein. This modal-shaped electrode, based on the orthogonal property of structural vibration modes, is characterized by full modal filtering to ensure that only the desired vibration mode is excited during operation. The newly developed piezoelectric transformer is comprised of three layers: a multilayered input layer, an insulation layer, and a single output layer. The electrode shape of the input layer is derived from its structural vibration modal shape, which takes advantage of the orthogonal property of the vibration modes to achieve a full modal filtering effect. The insulation layer possesses two functions: first, to couple the mechanical vibration energy between the input and output, and second, to provide electrical insulation between the two layers. To meet the two functions, a low temperature, co-fired ceramic (LTCC) was used to provide the high mechanical rigidity and high electrical insulation. It can be shown that this newly developed piezoelectric transformer has the advantage of possessing a more efficient energy transfer and a wider optimal working frequency range when compared to traditional piezoelectric transformers. A multilayer piezoelectric, transformer-based inverter applicable for use in LCD monitors or portable displays is presented as well. PMID:17328332

  19. Discovering lead-free perovskite solar materials with a split-anion approach

    NASA Astrophysics Data System (ADS)

    Sun, Yi-Yang; Shi, Jian; Lian, Jie; Gao, Weiwei; Agiorgousis, Michael L.; Zhang, Peihong; Zhang, Shengbai

    2016-03-01

    Organic-inorganic hybrid perovskite solar materials, being low-cost and high-performance, are promising for large-scale deployment of the photovoltaic technology. A key challenge that remains to be addressed is the toxicity of these materials since the high-efficiency solar cells are made of lead-containing materials, in particular, CH3NH3PbI3. Here, based on first-principles calculation, we search for lead-free perovskite materials based on the split-anion approach, where we replace Pb with non-toxic elements while introducing dual anions (i.e., splitting the anion sites) that preserve the charge neutrality. We show that CH3NH3BiSeI2 and CH3NH3BiSI2 exhibit improved band gaps and optical absorption over CH3NH3PbI3. The split-anion approach could also be applied to pure inorganic perovskites, significantly enlarging the pool of candidate materials in the design of low-cost, high-performance and environmentally-friendly perovskite solar materials.Organic-inorganic hybrid perovskite solar materials, being low-cost and high-performance, are promising for large-scale deployment of the photovoltaic technology. A key challenge that remains to be addressed is the toxicity of these materials since the high-efficiency solar cells are made of lead-containing materials, in particular, CH3NH3PbI3. Here, based on first-principles calculation, we search for lead-free perovskite materials based on the split-anion approach, where we replace Pb with non-toxic elements while introducing dual anions (i.e., splitting the anion sites) that preserve the charge neutrality. We show that CH3NH3BiSeI2 and CH3NH3BiSI2 exhibit improved band gaps and optical absorption over CH3NH3PbI3. The split-anion approach could also be applied to pure inorganic perovskites, significantly enlarging the pool of candidate materials in the design of low-cost, high-performance and environmentally-friendly perovskite solar materials. Electronic supplementary information (ESI) available: Detailed descriptions on the structure optimization and quasi-particle GW calculation. See DOI: 10.1039/c5nr04310g

  20. Polarity effect of electromigration on mechanical properties of lead-free solder joints

    NASA Astrophysics Data System (ADS)

    Ren, Fei

    The trend of electronic packaging is to package the chips and the associated interconnections in a compact way that allows high speed operation; that allows for sufficient heat removal; that can withstand the thermal cycling associated with the turning on and turning off of the circuits; and that protects the circuits from environmental attack. These goals require that flip chip solder joints have higher resistance to electromigration, stronger mechanical property to sustain thermal mechanical stress, and are lead-free materials to satisfy environment and health concern. With lots of work on chemical reaction, electromigration and mechanical study in flip chip solder joints, however, the interaction between different driving forces is still little known. As a matter of fact, the combination study of chemical, electrical and mechanical is more and more significant to the understanding of the behavior of flip chip solder joints. In this dissertation, I developed one dimensional Cu (wire)-eutectic SnAgCu(ball)-Cu(wire) structure to investigate the interaction between electrical and mechanical force in lead-free solder joints. Electromigration was first conducted. The mechanical behaviors of solder joints before, after, and during electromigration were examined. Electrical current and mechanical stress were applied either in serial or in parallel to the solder joints. Tensile, creep, and drop tests, combined with different electrical current densities (15x10 3A/cm2) and different stressing time (3144 hours), have been performed to study the effect of electromigration on the mechanical behavior of solder joints. Nano-indentation test was conducted to study the localized mechanical property of IMC at both interfaces in nanometer scale. Fracture images help analyze the failure mechanism of solder joints driven by both electrical and mechanical forces. The combination study shows a strain build-up during electromigration. Furthermore, a ductile-to-brittle transition in flip chip solder joints induced by electromigration is observed, in which the fracture position migrates from the middle to the cathode interface of the joint with increasing current density and time. The transition is explained by the polarity effect of electromigration, particular due to the accumulation of vacancies at the cathode interface.