Science.gov

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 188C. 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. Current Developments and Prospective of Lead-Free Piezoelectric Ceramics

    NASA Astrophysics Data System (ADS)

    Takenaka, Tadashi; Nagata, Hajime; Hiruma, Yuji

    2008-05-01

    The dielectric, ferroelectric and piezoelectric properties of perovskite ferroelectric and bismuth layered-structured ferroelectric (BLSF) ceramics are described being superior candidates for lead-free piezoelectric materials to reduce environmental damage. Perovskite-type ceramics seem to be suitable for actuator and high-power applications that require a large piezoelectric constant, d33, and a high Curie temperature, Tc, or a depolarization temperature, Td (>200 C). For BaTiO3-based solid solutions, (1-x)BaTiO3-x(Bi0.5K0.5)TiO3 (BT-BKT100x) ceramics, Tc increases with increasing amount of x. The BT-BKT20 + MnCO3 (0.1 wt %) ceramic shows a high Tc greater than 200 C and an electromechanical coupling factor of k33 =0.35. In the case of a(Bi1/2Na1/2)TiO3-b(Bi1/2K1/2)TiO3-cBaTiO3 [BNBK (100a/100b/100c)] solid solution ceramics, d33 is 191 pC/N for BNBK (85.2/2.8/12). KNbO3 (KN)-based ceramics are also a candidate for lead-free piezoelectrics. In Mn-doped KN ceramics, a higher k33 of 0.507 is obtained for KN + MnCO3 (0.1 wt %). On the other hand, BLSF ceramics seem to be excellent candidates as piezoelectric sensors for high temperatures and ceramic resonators with a high mechanical quality factor, Qm, and a low temperature coefficient of resonance frequency, TC-f. The k33 value of the donor (Nb)-doped and grain-oriented (HF) Bi4Ti3-xNbxO12 (BITN-x) ceramic is 0.39 for x=0.08 and is able to keep the same stable value up to 350 C. Nd(0.01) and V(0.75) co-doped Bi4Ti3O12 ceramics, BNTV(0.01, 0.75), show a relatively low TC-f. Bi3TiTaO9 (BTT)-based solid solution, Srx-1Bi4-xTi2-xTaxO9 [SBTT2(x)] (1?x?2), displays the high Qm value (=13500) in (p)-mode at x=1.25. For resonator applications, (Sr1-xCax)2Bi4Ti5O18 (SCBT) (0?x?0.5) ceramics are suitable.

  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. 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.

  5. 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.

  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 ? ? ) and ( MnNb ' - VO ? ? - 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. Phase Transitions in Lead-free Piezoelectric Ceramics Monitored by the Resonance Method

    NASA Astrophysics Data System (ADS)

    Pardo, L.; Garca, A.; Brebl, K.; Mercadelli, E.; Galassi, C.

    Ferroelectrics, like batio3 (bt) or binatio3 (bnt), were studied in the 1950s and are now revisited, due to the need for lead-free piezoceramics, according to worldwide directives for environmental protection. Poling some of these materials has shown a different physical mechanism than ferroelectric domain orientation, involving field-induced structural phase transitions from pseudo-cubic phases to ferro-piezoelectrically active ones. They also depolarize below the curie temperature due to a structural phase transition. Both poling and thermal depoling can be monitored by the measurement of the electromechanical resonances. Depoling of (1-x) bnt-xbt ceramics with x=0.04 (bnbt4) is here considered as a case study.

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

    NASA Astrophysics Data System (ADS)

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

    2014-03-01

    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. 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.

  12. Phase transition and high piezoelectricity in (Ba,Ca)(Ti1-xSnx)O3 lead-free ceramics

    NASA Astrophysics Data System (ADS)

    Zhu, Li-Feng; Zhang, Bo-Ping; Zhao, Xiao-Kun; Zhao, Lei; Yao, Fang-Zhou; Han, Xi; Zhou, Peng-Fei; Li, Jing-Feng

    2013-08-01

    The phase structure in the (Ba,Ca)(Ti1-xSnx)O3 lead-free ceramics was evolved from inceptive orthorhombic (O) at 0 ? x ? 0.04 to a two-phase coexistence of pseudocubic-orthorhombic (PC-O) at 0.06 ? x ? 0.10 and further to a multiphase coexistence of rhombohedral-pseudocubic-orthorhombic (R-PC-O) at x = 0.11. Due to the multiphase coexistence of R-PC-O at room temperature proved by X-ray diffraction, dielectric constant ?r and differential scanning calorimetry, an ultrahigh piezoelectric coefficient d33 = 670 pC/N and electrostrain 0.061% were achieved. The high d33 over 520 pC/N was stabilized in a wide compositional range of 0.07 ? x ? 0.11, suggesting that (Ba,Ca)(Ti,Sn)O3 ceramics are a promising candidate for the lead-free piezoelectric ceramics.

  13. Touch sensor for micromanipulation with pipette using lead-free (K,Na)(Nb,Ta)O3 piezoelectric ceramics

    NASA Astrophysics Data System (ADS)

    Motoo, Kohei; Arai, Fumihito; Fukuda, Toshio; Matsubara, Masato; Kikuta, Koichi; Yamaguchi, Toshiaki; Hirano, Shin-Ichi

    2005-11-01

    In the field of applied microbiology, a touch sensor for micromanipulation with a pipette is needed. Therefore, we previously developed a touch sensor using Pb(Zr,Ti)O3 (PZT). The piezoelectric material is used for vibration of the pipette and for measurement of the change in mechanical impedance caused by the pipette tip contacting the object being measured. However, the lead included in PZT can cause environmental problems. Therefore, in the present work, we developed a touch sensor using lead-free (K,Na)(Nb,Ta)O3 (KNNT) ceramics, which are strong candidates for lead-free piezoelectric ceramics. In this study, characteristics of a touch sensor utilizing piezoelectric vibration were theoretically derived. The results show that the piezoelectric constant d31 is very important: the higher the mode of vibration, the smaller the tip amplitude; the lower the mode of vibration, the higher the sensitivity. Also, the higher the elasticity or viscosity of the object in contact with the sensor, the higher the sensitivity. These theoretical results qualitatively correspond to the experimental results. The piezoelectric constant d31 of KNNT ceramics was measured, and its value was found to be greater than or equal to 100 pm/V. KNNT ceramics were applied to the touch sensor and its utility was confirmed.

  14. 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

  15. 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

  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 ?C 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. Piezoelectric Properties of LiSbO3-Modified (K0.48Na0.52)NbO3 Lead-Free Ceramics

    NASA Astrophysics Data System (ADS)

    Wu, Jiagang; Wang, Yuanyu; Xiao, Dingquan; Zhu, Jianguo; Yu, Ping; Wu, Lang; Wu, Wenjuan

    2007-11-01

    Lead-free piezoelectric (1-x)(K0.48Na0.52)NbO3-xLiSbO3 [(1-x)KNN-xLS] ceramics were prepared by conventional sintering. A morphotropic phase boundary (MPB) between the orthorhombic and tetragonal phases was identified in the composition range of 0.04ceramics near the MPB exhibit a strong compositional dependence, and good piezoelectric properties, temperature stability, and aging characteristics. It was found that the samples with 5 mol % LS exhibited enhanced electrical properties (d33 262 pC/N, kp 46%, Tc 373 C, To--t 60 C). These results show that (1-x)KNN-xLS ceramic is a promising lead-free piezoelectric material.

  20. 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

  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. Enhanced ferroelectricity, piezoelectricity, and ferromagnetism in Nd-modified BiFeO3-BaTiO3 lead-free ceramics

    NASA Astrophysics Data System (ADS)

    Zheng, Qiaoji; Luo, Lingling; Lam, Kwok Ho; Jiang, Na; Guo, Yongquan; Lin, Dunmin

    2014-11-01

    Lead-free multiferroic ceramics of 0.75Bi1-xNdxFeO3 - 0.25BaTiO3 + 1 mol. % MnO2 were prepared by a conventional ceramic technique and their structure, piezoelectricity, and multiferroicity were studied. The ceramics sintered at 890-990 C possess a pure perovskite structure. A morphotropic phase boundary of rhombohedral and monoclinic phases is formed at x = 0.05. A small amount of Nd improves the ferroelectric and piezoelectric properties of the ceramics. The ferroelectric-paraelectric phase transition becomes gradually diffusive with x increasing. After the addition of Nd, the ferromagnetism of the ceramics is greatly enhanced by 320%. The increase in sintering temperature improves significantly the ferroelectric, piezoelectric, and ferromagnetic properties of the ceramics. The ceramics with x = 0.05 sintered at 950-990 C possess improved ferroelectricity, piezoelectricity, magnetism and insulation with Pr of 16.5-17.5 ?C/cm2, d33 of 113-121 pC/N, Mr of 0.127-0.138 emu/g, R of 5 109 ?.cm and high TC of 473-482 C, indicating that the ceramic is a promising candidate for room-temperature multiferroic and high-temperature piezoelectric materials.

  3. Largely enhanced electromechanical properties of BaTiO3-(Na0.5Er0.5)TiO3 lead-free piezoelectric ceramics

    NASA Astrophysics Data System (ADS)

    Li, Jun; Chai, Xiaona; Peng, Dengfeng; Zou, Hua; Wang, Xusheng; Yao, Xi

    2014-08-01

    Lead-free (1 - x)BaTiO3-x(Na0.5Er0.5)TiO3 (0 ? x ? 0.15) ceramics were prepared by a solid state reaction method. Their structure and electric properties were analyzed. Rietveld refinements suggested that the ceramics crystallized in the tetragonal perovskite space group P4 mm at room temperature. With increasing x from 0 to 0.05, Na+/Er3+ co-substitution at Ba-site in BaTiO3 leads to the decrease of lattice parameters and unit cell volume. While minor secondary phase, Er2Ti2O7 and (TiO1.2)0.787, appears at x = 0.10 or above. A great enhancement of piezoelectric properties and other electric parameters was obtained in this system by properly moderating the compositions. For example, in the ceramics with composition x = 0.05, a large piezoelectric coefficient d33 (333 pm/V), a high remnant polarization Pr (14.3 ?C/cm2), a good planar electromechanical coupling factor kp (0.391), a mechanical quality factor Qm (97.3), and a high Curie temperature (TC = 134 C) (higher than that of pure BaTiO3) were achieved. Our results show that (1 - x)BaTiO3-x(Na0.5Er0.5)TiO3 ceramics are a good candidate of lead-free piezoelectric materials.

  4. 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.

  5. 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

    2015-10-01

    (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 960C. 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 ? cm to 2.1 109 ? cm), piezoelectricity (d 33 65 pC/N to 106 pC/N) and ferroelectricity (P r 6.38 ?C/cm2 to 22.89 ?C/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.

  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. 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.

  8. 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-?-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.

  9. Polymorphic structure evolution and large piezoelectric response of lead-free (Ba,Ca)(Zr,Ti)O{sub 3} ceramics

    SciTech Connect

    Tian, Ye; Chao, Xiaolian E-mail: yangzp@snnu.edu.cn; Wei, Lingling; Liang, Pengfei; Yang, Zupei E-mail: yangzp@snnu.edu.cn; Jin, Li

    2014-03-17

    The polymorphic structure evolution of (Ba,Ca)(Zr,Ti)O{sub 3} piezoelectric ceramics was investigated by analysis of the in situ X-ray diffraction and dielectric spectra. The results indicated that a confined orthorhombic (O) phase region induced by the approach of the rhombohedral (R) and tetragonal (T) phases existed in an extremely narrow temperature range of (Ba{sub 0.85}Ca{sub 0.15})(Zr{sub 0.1}Ti{sub 0.9})O{sub 3} composition. The electric properties near the OT phase boundaries of (Ba{sub 0.95}Ca{sub 0.05})(Zr{sub 0.05}Ti{sub 0.95})O{sub 3} and (Ba{sub 0.85}Ca{sub 0.15})(Zr{sub 0.1}Ti{sub 0.9})O{sub 3} were compared. The results suggested that the confined O phase region is an important factor that contributes to the extremely large piezoelectric response.

  10. 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.

  11. 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.

  12. 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

  13. Fabrication of Lead-Free Lithium-Doped Na0.5K0.5NbO3 Piezoelectric Ceramics with Dense Grain Structure Using Sol-Gel Surface Coating

    NASA Astrophysics Data System (ADS)

    Lim, Sun Kyung; Han, Jeong Seon; Yoo, Ae Ri; Lee, Seong Eui; Lee, Hee Chul

    2013-10-01

    Lead-free piezoelectric 0.06(LiNbO3)-0.94(Na0.5K0.5)NbO3 (LNKN) ceramics in disc form were fabricated and characterized to acquire good electromechanical properties. A molding method including cold isostatic pressing (CIP) was used to form a dense and regular microstructure and suppress the cracking problems of LNKN ceramics during the following high-temperature sintering. The LNKN ceramic sintered at 1040 C showed a high piezoelectric constant d33 of 170 pC/N owing to its high density. Furthermore, perovskite LNKN films with the same composition as the ceramics were fabricated using 2-methoxyethanol-based sol-gel solution. The sol-gel surface coating on the LNKN ceramics was found to be very effective for increasing the piezoelectric constant because of the interface stabilization effect leading to a uniform electric field in piezoelectric elements. As a result, we obtained the highest piezoelectric constant d33 of 183 pC/N. The lead-free LNKN ceramics are promising for applications in eco-friendly ferroelectric and piezoelectric devices.

  14. 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.

  15. 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.

  16. Enhanced piezoelectric properties of BaZrO3-substituted 0.67BiFeO3-0.33BaTiO3 lead-free ceramics

    NASA Astrophysics Data System (ADS)

    Park, J. S.; Lee, M. H.; Kim, D. J.; Kim, M.-H.; Song, T. K.; Kim, S. W.; Kim, W.-J.; Kumar, S.

    2015-04-01

    Lead-free ceramics with compositions of (1- x)[0.67Bi1.05FeO3-0.33BaTiO3]- xBaZrO3 ( x = 0.00, 0.01, 0.02, 0.03, 0.04, and 0.05) [BF-BT-BZ x] have been prepared through a conventional solid-state reaction method. The effects of BZ substitution on the crystal structural, microstructural, piezoelectric, and electrical properties of the ceramics were investigated. The X-ray diffraction patterns revealed that all ceramics were formed with a mixed structure of rhombohedral and tetragonal perovskite phases. For x = 0.03, good ferroelectric and piezoelectric properties were observed: 2 P r = 43 ?C/cm2 and 2 E c = 61 kV/cm. The static- and dynamic-piezoelectric constants were observed to be 52 pC/N and 330 pm/V, respectively.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. Phase transition temperatures and piezoelectric properties of (Bi(1/2)Na(1/2))TiO3- and (Bi(1/2)K(1/2))TiO3-based bismuth perovskite lead-free ferroelectric ceramics.

    PubMed

    Takenaka, Tadashi; Nagata, Hajime; Hiruma, Yuji

    2009-08-01

    The phase transition temperatures and the dielectric, ferroelectric, and piezoelectric properties of bismuth perovskite lead-free ferroelectric ceramics such as (Bi(1/2)Na(1/2))TiO3 (BNT)- and (Bi(1/2)Na(1/2))TiO3 (BKT)-based solid solutions have been reviewed. According to the results obtained by our group, these ceramics can be considered as superior lead-free piezoelectric materials for reducing environmental damage. Perovskite-type ceramics appear to be suitable for actuator and high-power applications that require a large piezoelectric constant d33 and a high Curie temperature TC or a high depolarization temperature Td (> 200 degrees C). In this paper, we summarize the relationship between phase transition temperatures and piezoelectric properties. In the case of the BNT-based solid solutions, the highest piezoelectric properties were obtained at the morphotropic phase boundary (MPB) between rhombohedral and tetragonal phases. However, d33 and Td were shown to have a tradeoff relationship. Considering the high Td and high d33, the tetragonal side of the MPB composition is suitable for piezoelectric actuator application. Meanwhile, the Qm values on the rhombohedral side of the MPB composition were better than those on the tetragonal side, and excellent high-power characteristics were obtained for Mn-doped BNT-(Bi(1/2)Na(1/2))TiO3-BKT ternary systems with rhombohedral symmetry. BKT ceramics were prepared by the hot-pressing (HP) method, and their ferroelectric and piezoelectric properties were clarified. BKT ceramics doped with a small amount of Bi have a relatively high remanent polarization of Pr = 27.6 microC/cm2 and high piezoelectric properties (k33 = 0.40 and d33 = 101 pC/N). In addition, it was clarified that BKT ceramics have a high Td of approximately 300 degrees C. The solid solution (1-x)BKT-xBaTiO3 (BKT-BT100x) exhibited a high Td of approximately 300 degrees C at x > 0.4. PMID:19686975

  3. 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.

  4. Dielectric properties in lead-free piezoelectric (Bi0.5Na0.5)TiO3-BaTiO3 single crystals and ceramics

    NASA Astrophysics Data System (ADS)

    Chen, C.-S.; Tu, C. S.; Chen, P.-Y.; Ting, Y.; Chiu, S.-J.; Hung, C. M.; Lee, H.-Y.; Wang, S.-F.; Anthoninappen, J.; Schmidt, V. H.; Chien, R. R.

    2014-05-01

    The 0.93(Bi0.5Na0.5)TiO3-0.07BaTiO3 (BNB7T) piezoelectric single crystals and ceramics have been grown respectively by using the self-flux and solid-state-reaction methods. The real (??) and imaginary (??) parts of the dielectric permittivity of BNB7T crystals and ceramics were investigated with and without an electric (E) poling as functions of temperature and frequency. The BNB7T crystal shows a stronger dielectric maximum at Tm~240 C than the ceramic at Tm~300 C. The dielectric permittivity of BNB7T ceramic shows an extra peak after poling at an electric field E=40 kV/cm in the region of 80-100 C designated as the depolarization temperature (Td). A wide-range dielectric thermal hysteresis was observed in BNB7T crystal and ceramic, suggesting a first-order-like phase transition. The dielectric permittivity ?? obeys the Curie-Weiss equation, ??=C/(T-To), above 500 C, which is considered as the Burns temperature (TB), below which polar nanoregions begin to develop and attenuate dielectric responses.

  5. 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.

  6. 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.

  7. 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

  8. 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

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

    SciTech Connect

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

    2010-05-15

    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 (H{sub Bias}) of 0.6 kOe. This work shows the potential of BNKLBT lead-free ceramics in ME sensing application.

  10. Improved temperature stability of CaTiO{sub 3}-modified [(K{sub 0.5}Na{sub 0.5}){sub 0.96}Li{sub 0.04}](Nb{sub 0.91}Sb{sub 0.05}Ta{sub 0.04})O{sub 3} lead-free piezoelectric ceramics

    SciTech Connect

    Wu Jiagang; Xiao Dingquan; Wu Wenjuan; Zhang Bin; Zhu Jianguo; Wang Yuanyu

    2008-07-15

    The CaTiO{sub 3}-modified [(K{sub 0.5}Na{sub 0.5}){sub 0.96}Li{sub 0.04}](Nb{sub 0.91}Sb{sub 0.05}Ta{sub 0.04})O{sub 3} lead-free piezoelectric ceramics were prepared using normal sintering for improving the temperature stability of (K{sub 0.5}Na{sub 0.5})NbO{sub 3}-based ceramics. The effects of the CaTiO{sub 3} on the temperature stability and piezoelectric properties of the ceramics were systematically studied. These results show that the CaTiO{sub 3}-modified [(K{sub 0.5}Na{sub 0.5}){sub 0.96}Li{sub 0.04}](Nb{sub 0.91}Sb{sub 0.05}Ta{sub 0.04})O{sub 3} lead-free piezoelectric ceramics possess good temperature stability in the polymorphic phase transition below room temperature, and also exhibit high piezoelectric properties (d{sub 33}=263 pC/N and k{sub p}=50%) when the ceramics were poled at an optimum poling temperature. These results indicate that the ceramic is a promising candidate material for lead-free piezoelectric ceramics.

  11. 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.

  12. 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

  13. 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

  14. Piezoelectric properties in (K0.5Bi0.5)TiO3-(Na0.5Bi0.5)TiO3-BaTiO3 lead-free ceramics.

    PubMed

    Zhang, Shujun; Shrout, Thomas R; Nagata, Hajime; Hiruma, Yuji; Takenaka, Tadashi

    2007-05-01

    Lead-free piezoelectric ceramics with compositions around the morphotropic phase boundary (MPB) x(Na0.5Bi0.5)TiO3-y(K0.5Bi0.5)TiO3-zBaTiO3 [x + y + z = 1; y:z = 2:1] were synthesized using conventional, solid-state processing. Dielectric maximum temperatures of 280 degrees C and 262 degrees C were found for tetragonal 0.79(Na0.5Bi0.5)TiO3-0.14(K0.5Bi0.5)TiO3-0.07BaTiO3 (BNBK79) and MPB composition 0.88(Na0.5Bi0.5)TiO3-0.08(K0.5Bi0.5)TiO3-0.04BaTiO3 (BNBK88), with depolarization temperatures of 224 degrees C and 162 degrees C, respectively. Piezoelectric coefficients d33 were found to be 135 pC/N and 170 pC/N for BNBK79 and BNBK88, and the piezoelectric d31 was determined to be -37 pC/N and -51 pC/N, demonstrating strong anisotropy. Coercive field values were found to be 37 kV/cm and 29 kV/cm for BNBK79 and BNBK88, respectively. The remanent polarization of BNBK88 (approximately 40 microC/cm2) was larger than that of BNBK79 (approximately 29 microC/cm2). The piezoelectric, electromechanical, and high-field strain behaviors also were studied as a function of temperature and discussed. PMID:17523555

  15. 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 ?C/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 (?'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.

  16. 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

  17. 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

  18. Properties of (Bi0.5Na0.5)TiO3-BaTiO3-(Bi0.5Na0.5)(Mn1/3Nb2/3)O3 Lead-Free Piezoelectric Ceramics and Its Application to Ultrasonic Cleaner

    NASA Astrophysics Data System (ADS)

    Tou, Tonshaku; Hamaguti, Yuki; Maida, Yuichi; Yamamori, Haruo; Takahashi, Kazutoshi; Terashima, Yoshimitsu

    2009-07-01

    The lead-free piezoelectric ceramics 0.82(Bi0.5Na0.5)TiO3-0.15BaTiO3-0.03(Bi0.5Na0.5)(Mn1/3Nb2/3)O3 (abbreviated as BNT-BT-BNMN) was prepared by a conventional process of ceramic engineering. The X-ray diffractometer (XRD) analysis showed that all compositions could form a single perovskite phase. The ceramics showed excellent piezoelectric properties with a coupling factor kt=41%, a mechanical quality factor Qm=500, a piezoelectric constant d33=110 pC/N, a relative permittivity ?33T/?0=520, a dissipation factor tan ?=0.66%, a Curie point Tc=260 C, and a density ?=5.5 g/cm3. The physical properties of the ceramics were superior to those of hard Pb(Zr,Ti)O3 (PZT). The high-power characteristics of the ceramics were superior to those of hard PZT. A cylinder sample of lead-free ceramics was used to fabricate a bolt-clamped Langevin transducer (BLT) for application in the ultrasonic cleaner. The vibration velocity of BLT using the ceramics was higher than that of hard PZT under the same input power. The cleaning effect of an ultrasonic cleaner using the BLTs was very high and sufficiently good for commercial application.

  19. 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.

  20. 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.

  1. 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

  2. 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.

  3. 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

  4. 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.

  5. 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.

  6. High electrostrictive coefficient Q33 in lead-free Ba(Zr0.2Ti0.8)O3-x(Ba0.7Ca0.3)TiO3 piezoelectric ceramics

    NASA Astrophysics Data System (ADS)

    Li, Fei; Jin, Li; Guo, Runping

    2014-12-01

    In this study, the electrostrictive effect in Ba(Zr0.2Ti0.8)O3-x(Ba0.7Ca0.3)TiO3 (BZT-xBCT, x = 0.4, 0.5, and 0.6) ceramics was investigated to gain understanding of their high piezoelectric activity. The electrostrictive coefficient Q33 of the BZT-xBCT ceramics was observed to be around 0.04 m4/C2, twice that reported for Pb(Zr,Ti)O3-based ceramics. The Q33 was found to be quite stable with respect to temperature and composition for the BZT-xBCT ceramics. The addition of Fe3+ dopant to the ceramics greatly decreased their Curie temperature without affecting their Q33, which remained 0.04 m4/C2. Moreover, a high and hysteresis-free electric-field-induced strain was obtained for 2 at. % Fe-doped BZT-0.5BCT ceramics at room temperature, caused by their high Q33 coefficient and lower-than-room-temperature Curie temperature. The small-signal M33 coefficient of 2 at. % Fe-doped BZT-0.5BCT ceramics was found to be 1.5 10-16 m2/V2 (0.32 10-16 m2/V2 for undoped counterpart). These results indicate that 2 at. % Fe-doped BZT-0.5BCT ceramics have great potential as alternatives for hard Pb(Zr,Ti)O3 ceramics in actuator applications, where reproducible and non-hysteretic deformation responses are required.

  7. Dielectric, piezoelectric, and ferroelectric properties of MnCO3-added 74(Bi(1/2)Na(1/2)) TiO3-20.8(Bi(1/2)K(1/2))TiO3-5.2BaTiO3 lead-free piezoelectric ceramics.

    PubMed

    Hu, Hanchen; Zhu, Mankang; Hou, Yudong; Yan, Hui

    2009-05-01

    74(Bi(1/2)Na(1/2))TiO3-20.8(Bi(1/2)K(1/2))TiO3-5.2BaTiO3-x MnCO3 lead-free piezoelectric ceramics were synthesized by conventional solid oxide routine. The tetragonal 74(Bi(1/2)Na(1/2))TiO3-20.8(Bi(1/2)K(1/2))TiO3-5.2 BaTiO3 (BNKB) exhibits high depolarization temperature T(d) of 195 degrees C; however, its properties are far from satisfactory for practical application and need to be improved. The experiments show that the addition of MnCO3 reduces the tetragonality c/a and increases the cell volume. In addition, it revealed that the suitable addition of MnCO3 promotes the sintering and increases the densities of BNKB ceramics. The addition of MnCO3 also enhances the relaxor behavior of BNKB ceramics due to the reconstruct of the disorder arrays. Due to the effect of the crystal lattice, grain growth, and relaxor behavior, the optimal electric properties were realized at MnCO3 addition x of 0.16: the dielectric permittivity epsilon(r) = 1047, dielectric dissipation tandelta = 0.022, piezoelectric strain d33 = 140 pC/N, mechanical coupling k(p) = 0.18, mechanical quality Q(m) = 89 while the depolarization temperature T(d) stays relatively high at 175 degrees C. The effect and mechanism of Mn doping on the electrical properties were discussed in detail. PMID:19473907

  8. 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.

  9. 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.

  10. Dielectric behavior and microstructure of (Bi{sub 1/2}Na{sub 1/2})TiO{sub 3}-(Bi{sub 1/2}K{sub 1/2})TiO{sub 3}-BaTiO{sub 3} lead-free piezoelectric ceramics

    SciTech Connect

    Wang, X.X.; Choy, S.H.; Tang, X.G.; Chan, H.L.W.

    2005-05-15

    (0.95-x)(Bi{sub 1/2}Na{sub 1/2})TiO{sub 3}-x(Bi{sub 1/2}K{sub 1/2})TiO{sub 3}-0.05BaTiO{sub 3} lead-free piezoelectric ceramics (abbreviated as BNT-BKT-BT100x with x varying from 0 to 20 mol %) are prepared by a solid-state reaction process. Variation of the dielectric properties and microstructure of BNT-BKT-BT100x ceramics with BKT content is studied. The results indicate that the relative permittivity {epsilon}{sub r} and loss tangent tan {delta} vary with the BKT amount. Scanning electron microscope observation also indicates that BKT in high amount affects the microstructure. X-ray diffraction analysis shows that the incorporated BKT diffuses into the BNT-BT lattice to form a solid solution during sintering.

  11. 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 todays 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

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

    SciTech Connect

    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(Bi{sub 0.5}Na{sub 0.5})TiO{sub 3}-0.05(Bi{sub 0.5}K{sub 0.5})TiO{sub 3}-0.015(Bi{sub 0.5}Li{sub 0.5}= )TiO{sub 3}-0.05BaTiO{sub 3}, BNKLBT-1.5, has been fabricated by a powder-based extrusion method. The ceramic fibers with 400 {mu}m diameter were well crystallized after being calcined at 800 deg. C and sintered at 1170 deg. C. The piezoelectric and ferroelectric properties of the single fiber were found to be 155 pC/N and {approx}34.5 {mu}C/cm{sup 2}, 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.

  13. 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

  14. 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)

  15. Electrical properties of lead-free 0.98(Na0.5K0.5)NbO3-0.02Ba(Zr0.52Ti0.48)O3 piezoelectric ceramics by optimizing sintering temperature.

    PubMed

    Lee, Seung-Hwan; Lee, Sung-Gap; Lee, Young-Hie

    2012-01-01

    Lead-free 0.98(Na0.5K0.5)NbO3-0.02Ba(Zr0.52Ti0.48)O3 [0.98NKN-0.02BZT] ceramics were fabricated by the conventional mixed oxide method with sintering temperature at 1,080C to 1,120C. The results indicate that the sintering temperature obviously influences the structural and electrical properties of the sample. For the 0.98NKN-0.02BZT ceramics sintered at 1,080C to 1,120C, the bulk density increased with increasing sintering temperature and showed a maximum value at a sintering temperature of 1,090C. The dielectric constant, piezoelectric constant [d33], electromechanical coupling coefficient [kp], and remnant polarization [Pr] increased with increasing sintering temperature, which might be related to the increase in the relative density. However, the samples would be deteriorated when they are sintered above the optimum temperature. High piezoelectric properties of d33 = 217 pC/N, kp = 41%, dielectric constant = 1,951, and ferroelectric properties of Pr = 10.3 ?C/cm2 were obtained for the 0.98NKN-0.02BZT ceramics sintered at 1,090C for 4 h. PMID:22221445

  16. 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 ?C/cm2 and 98 pC/N for x = 0 to 31 ?C/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.

  17. 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

  18. 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/?g. Its good performance shows that the piezoelectric diaphragm biosensor can be used as a cost-effective platform for nucleic acid testing. PMID:26771617

  19. 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 ?C/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).

  20. 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

  1. 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

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. Lead-free piezoceramics.

    PubMed

    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 300 picocoulombs per newton (pC N(-1)), and texturing the material leads to a peak d33 of 416 pC N(-1). The textured material also exhibits temperature-independent field-induced strain characteristics. PMID:15516921

  9. 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.

  10. 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

  11. Disc piezoelectric ceramic transformers.

    PubMed

    Erhart, Jiri; P?lpn, Petr; Dole?ek, Roman; Psota, Pavel; Ldl, Vt

    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 ? to 10 k?, 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

  12. 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

  13. 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 pCN-1) than traditional piezoelectric ceramics (131 pCN-1). On this basis therefore, a strategy for the future study and development of lead-free KNN-based piezoelectric glass ceramics is proposed.

  14. 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 PE 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.

  15. 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.

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

    NASA Astrophysics Data System (ADS)

    Bochenek, Dariusz; Niemiec, Przemys?aw; Adamczyk, Ma?gorzata

    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.

  17. Effect of crystallographic orientation in textured Ba0.92Ca0.08TiO3 piezoelectric ceramics

    NASA Astrophysics Data System (ADS)

    Haugen, Astri Bjrnetun; Morozov, Maxim I.; Johnsson, Mats; Grande, Tor; Einarsrud, Mari-Ann

    2014-10-01

    Strongly textured lead-free Ba0.92Ca0.08TiO3 piezoelectric ceramics were fabricated by tape casting and templated grain growth. Dense ceramics with both favorable ?100? and unfavorable ?111? texture were successfully prepared. Enhanced piezoelectric performance was demonstrated for ceramics with ?100? texture, in line with the predictions based on reported piezoelectric coefficients of tetragonal BaTiO3. Due to the expanded tetragonal range through Ca-substitution, ?100? texture is favorable over a wide temperature range. The ?100? texture also results in the enhanced piezoelectric performance being temperature-independent. In addition to engineering of stable, high-performance lead-free piezoelectric ceramics, this study has demonstrated that consideration of the extender/rotator nature of piezoelectric properties is imperative for improving the piezoelectric response through texturing.

  18. 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

  19. 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 ?Tmax = 0.73 K is measured at 160 C under 22 kV/cm. This corresponds to an ECE responsivity (?T/?E) 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.

  20. 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

  1. 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.

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

    PubMed

    Pramanick, Abhijit; Jrgensen, 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

  3. Structure and temperature dependent electrical properties of lead-free Bi0.5Na0.5TiO3- SrZrO3 ceramics

    NASA Astrophysics Data System (ADS)

    Maqbool, Adnan; Rahman, Jamil ur; Hussain, Ali; Park, Jong Kyu; Gone Park, Tae; Song, Jae Sung; Kim, Myong Ho

    2014-06-01

    Lead-free SrZrO3-modified Bi0.5Na0.5TiO3 (BNT-SZ) ceramics were fabricated by a conventional solid state reaction method. X-ray diffraction analysis reveals a pure perovskite phase without any traces of secondary phases. Scanning electron microscopy images depicts dense grain morphology. The temperature dependences of the dielectric behavior was measured in the temperature range of 50-500 C at 100 kHz. With the increase in SZ content, the dielectric constant (?r) constantly decreased and the maximum dielectric constant temperature (Tm) shifted towards lower temperatures. In addition to this, ferroelectric hysteresis loops indicated a disruption of ferroelectric order and increase in the relaxor character of BNT ceramics with increase in SZ concentration. A maximum values of remnant polarization (32 ?C/cm2) and piezoelectric constant (100 pC/N) were observed at SZ5 and SZ4, respectively.

  4. Compositional dependence of phase structure and electrical properties in (K0.42Na0.58)NbO3-LiSbO3 lead-free ceramics

    NASA Astrophysics Data System (ADS)

    Wu, Jiagang; Xiao, Dingquan; Wang, Yuanyu; Zhu, Jianguo; Yu, Ping; Jiang, Yihang

    2007-12-01

    (1-x)(K0.42Na0.58)NbO3-xLiSbO3 [(1-x)KNN-xLS] lead-free piezoelectric ceramics were prepared by the conventional mixed oxide method. The compositional dependence of the phase structure and the electrical properties of the ceramics were studied. A morphotropic phase boundary (MPB) between the orthorhombic and tetragonal phases was identified in the composition range of 0.04ceramics near the MPB exhibit a strong compositional dependence and enhanced piezoelectric properties. The ceramics with 5 mol. % LS exhibit enhanced electrical properties (d33270 pC/N, kp47.2%, Tc364 C , To-t=35 C, ?r1412, tan ? 2.8%, and Pr25.7 ?C/cm2; Ec11.1 kV/cm) and possess low dielectric loss (<2%) at 10 and 100 kHz at high temperature (250-400 C). The low dielectric loss at high temperature is very important for high-temperature application of the ceramics. The related mechanism of the enhanced electrical properties of the ceramics was also discussed. These results show that (1-x)KNN-xLS (x =0.05) ceramic is a promising lead-free piezoelectric material.

  5. 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 = 02%) 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 PE 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 PE loops in KNNC ceramics under high doping levels (x > 1%).

  6. 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

  7. 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

  8. 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

  9. Growth and characterization of undoped and Mn doped lead-free piezoelectric NBTKBT 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.

  10. 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.

  11. Effect of Heat Treatment Conditions on Properties of Lead-Free Bi2GeO5 Ferroelectric Glass Ceramics

    NASA Astrophysics Data System (ADS)

    Kantha, P.; Pengpat, K.; Rujijanagul, G.; Tunkasiri, T.; Eitssayeam, S.; Intatha, U.; Sirisoonthorn, S.

    2009-07-01

    Nowadays, lead-free ferroelectric materials have attracted much interest among materials scientists as a result of environmental concern. The bismuth germanate (Bi2GeO5) phase, one of the lead-free ferroelectric crystals, is of particular interest as its composition already contains good glass former (GeO2) and can be prepared by an alternative glass ceramic route. In this work, the conventional melt-quenching method was used to produce the parent glass with composition of 60 mol% BiO1.5:20 mol% GeO2:20 mol% BO1.5. The as-received glass pieces were subjected to the heat treatment schedule at various crystallization temperatures and dwell-times. The glass and glass ceramics samples were then investigated by XRD, Raman spectroscopy and their dielectric properties were also measured. The XRD and Raman spectroscopy showed that the crystallinity of the prepared glass ceramics depended very much on crystallization temperature and dwell-time. The larger dielectric constant and lower dielectric loss were obtained as crystallinity of the glass ceramics enhanced. The highest dielectric constant (?r) was found at 77 with a low dielectric loss of about 0.005.

  12. 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.

  13. 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.

  14. The characterisation of lead-free thick-film resistors on different low temperature Co-fired ceramics substrates

    SciTech Connect

    Hrovat, Marko; CoE NAMASTE, Jamova Cesta 39, SI-1000 Ljubljana ; Kielbasinski, Konrad; Institute of Microelectronics and Optoelectronics, Warsaw University of Technology, Koszykowa 75, 00-662 Warsaw ; Makarovi?, Kostja; CoE NAMASTE, Jamova Cesta 39, SI-1000 Ljubljana ; Belavi?, Darko; CoE NAMASTE, Jamova Cesta 39, SI-1000 Ljubljana ; Jakubowska, Malgorzata; Faculty of Mechatronics, Warsaw University of Technology, ?w. Andrzeja Boboli 8, 02-525 Warsaw

    2012-12-15

    Graphical abstract: Display Omitted Highlights: ? Lead free thick film resistors based on ruthenium oxide were developed. ? The compatibility of resistors with different LTCC substrates was evaluated. ? The interactions between resistors and glassy LTCC substrates were not detected. ? Electrical characteristics were comparable with commercial thick film resistors. -- Abstract: Lead-free thick-film resistors were synthesised and investigated. The thick-film resistor materials with nominal sheet resistivities from 50 ohm/sq. to 50 kohm/sq. were prepared using combinations of two lead-free glasses with reflow temperatures at 940 C and 1240 C, respectively, and two RuO{sub 2} powders (fine-grained and coarse-grained RuO{sub 2}). The thick-film resistors were printed and fired on alumina and on low temperature co-fired ceramics substrates and fired at 850 C and 950 C. The fired resistors were investigated by X-ray powder diffraction, by scanning electron microscopy and by energy dispersive X-ray analysis. The sheet resistivities, temperature coefficients of resistivity, gauge factors and noise indices were measured.

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

    SciTech Connect

    Chauhan, Aditya; Patel, Satyanarayan; Vaish, Rahul

    2014-08-15

    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(Bi{sub 0.5}Na{sub 0.5})TiO{sub 3}-0.07BaTiO{sub 3}-0.02(K{sub 0.5}Na{sub 0.5})NbO{sub 3} 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{sup -3} was obtained at 100 MPa applied stress (25{sup o}C). While a maximum energy density of 568 mJ.cm{sup -3} was obtained for the same stress at 80{sup o}C. 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.

  16. 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.

  17. 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

  18. 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

  19. Fabrication and Piezoelectric Property of Highly Textured CaBi2Nb2O9 Ceramics by Tape Casting

    NASA Astrophysics Data System (ADS)

    Chen, Huanbei; Fu, Fang; Zhai, Jiwei

    2011-05-01

    Textured high-Curie-point lead-free piezoelectric ceramics, CaBi2Nb2O9 (CBN), were prepared by the tape casting method. Highly textured ceramics with a single phase and 95% Lotgering factor were obtained by the templated grain growth (TGG) technique. The textured CBN ceramics had a higher piezoelectric constant (d33 = 17.8 pC/N) than their non textured counterparts (d33 = 6.2 pC/N) prepared by a conventional solid-state sintering process. Furthermore, they had excellent thermostable of piezoelectric properties from room temperature to near Curie temperature. This type of textured CBN ceramic that can be prepared using the low-cost and scalable tape casting technique should be a promising candidate for high-temperature piezoelectric applications.

  20. 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; Rdel, 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

  1. 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.

  2. 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

  3. 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 (~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

  4. 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.

  5. Lead-free piezoelectric ceramics based on (0.97 - x)K0.48Na0.52NbO3-0.03Bi0.5(Na0.7K0.2Li0.1)0.5ZrO3-xB0.5Na0.5TiO3 ternary system

    NASA Astrophysics Data System (ADS)

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

    2013-09-01

    In this work, the ternary system of potassium-sodium niobate has been designed to enhance the piezoelectric properties without sacrificing the Curie temperature greatly, and (0.97 - x)K0.48Na0.52NbO3-0.03Bi0.5(Na0.7K0.2Li0.1)0.5ZrO3-xB0.5Na0.5TiO3 ceramics have been prepared by the conventional solid-state method. The effect of B0.5Na0.5TiO3 content on the microstructure and electrical properties of the ceramics is studied. The phase diagram shows a phase boundary of the rhombohedral-tetragonal (R-T) phase coexistence in the composition range of 0.5% < x < 1.5%, and then an enhanced dielectric, ferroelectric, and piezoelectric behavior is obtained at such a phase boundary zone. The ceramic with x = 0.01 has an optimum electrical behavior of d33 285 pC/N, kp 0.40, ?r 1235, tan ? 0.031, Pr 14.9 ?C/cm2, and Ec 15.2 kV/cm, together with a high Curie temperature of 347 C. The large d33 in such a ternary system is due to a composition-induced R-T phase transition and a higher ?rPr, and the thermal stability performance is strongly dependent on the phase structure. As a result, the design of the ternary system is an effective way to enhance the piezoelectric properties of potassium-sodium niobate materials.

  6. Piezoelectric and pyroelectric properties of ferroelectric glass-ceramics

    NASA Astrophysics Data System (ADS)

    Wu, Mian-Xue; Zhu, Pei-nan

    1985-05-01

    In this paper we report the ferroelectric glass-ceramics possessing both piezoelectric and pyroelectric properties. The properties can be comparable to those of corresponding ceramics or single crystals.

  7. 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.

  8. Structure, electrical properties of Bi(Fe, Co)O3-BaTiO3 piezoelectric ceramics with improved Curie temperature

    NASA Astrophysics Data System (ADS)

    Zhou, Changrong; Cen, Zhenyong; Yang, Huabin; Zhou, Qin; Li, Weizhou; Yuan, Changlai; Wang, Hua

    2013-02-01

    Dense (1-y)BiFe1-xCoxO3-yBaTiO3 (BFC-BTx, y=0.29, x=0-0.012) high-temperature lead-free ceramics were prepared by the conventional oxide-mixed method and the effects of BiCoO3 modification on microstructural, electrical properties and their Curie temperatures were investigated. The solid solutions show a single phase perovskite structure, and the content of BiCoO3 has a significant effect on the microstructure of ceramics. The BFC-BTx ceramics exhibit improved Curie temperature Tc, together with increased piezoelectric properties. In particular, x=0.6% BFC-BTx ceramics, with a Curie temperature, Tc, of ?488 C, show optimum piezoelectric properties of d33=167 pC/N, kp=0.32. The combination of good piezoelectric properties and high Tc makes these ceramics suitable for elevated temperature piezoelectric devices.

  9. 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

  10. 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.

  11. 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.

  12. Origin of high piezoelectric activity in perovskite ferroelectric ceramics

    NASA Astrophysics Data System (ADS)

    Zeng, Weidong; Zhou, Xiujuan; Chen, Jun; Liao, Jiayi; Zhou, Changrong; Cen, Zhenyong; Yang, Tao; Yang, Huabin; Zhou, Qin; Chen, Guohua; Yuan, Changlai

    2014-06-01

    Dense (1-x)(Bi0.5Na0.5)TiO3-xBaTiO3 (BNT-BTx%, x = 3, 5, 6, and 7) ceramics exhibit large piezoelectricity for electrical poling below coercive fields. In particular, the piezoelectric activity and permittivity frequency dispersion have been found to be closely related. The significantly increased piezoelectric constant and sharply decreased permittivity frequency dispersion are observed to occur for poled ceramics under the critical poling electrical fields. These results suggest that the high piezoelectric response stems from poling electrical fields-induced-ordered nanodomains.

  13. 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.

  14. 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.

  15. 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

  16. Effect of Heat Treatment Conditions on Properties of Lead-Free Bi{sub 2}GeO{sub 5} Ferroelectric Glass Ceramics

    SciTech Connect

    Kantha, P.; Pengpat, K.; Rujijanagul, G.; Tunkasiri, T.; Eitssayeam, S.; Intatha, U.; Sirisoonthorn, S.

    2009-07-23

    Nowadays, lead-free ferroelectric materials have attracted much interest among materials scientists as a result of environmental concern. The bismuth germanate (Bi{sub 2}GeO{sub 5}) phase, one of the lead-free ferroelectric crystals, is of particular interest as its composition already contains good glass former (GeO{sub 2}) and can be prepared by an alternative glass ceramic route. In this work, the conventional melt-quenching method was used to produce the parent glass with composition of 60 mol% BiO{sub 1.5}:20 mol% GeO{sub 2}:20 mol% BO{sub 1.5}. The as-received glass pieces were subjected to the heat treatment schedule at various crystallization temperatures and dwell-times. The glass and glass ceramics samples were then investigated by XRD, Raman spectroscopy and their dielectric properties were also measured. The XRD and Raman spectroscopy showed that the crystallinity of the prepared glass ceramics depended very much on crystallization temperature and dwell-time. The larger dielectric constant and lower dielectric loss were obtained as crystallinity of the glass ceramics enhanced. The highest dielectric constant (epsilon{sub r}) was found at 77 with a low dielectric loss of about 0.005.

  17. 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.}

  18. 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.

  19. 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

  20. 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

  1. LARGE PIEZOELECTRIC EFFECT IN LOW-TEMPERATURE-SINTERED LEAD-FREE (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 THICK FILMS

    NASA Astrophysics Data System (ADS)

    Feng, Zuyong; Shi, Dongqi; Dou, Shixue; Hu, Yihua; Tang, Xingui

    2012-09-01

    High-quality piezoelectric (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 thick films with dense and homogenous microstructures were fabricated at a low sintering temperature (900C) using a CuBi2O4 sintering aid. The 10 ?m thick film exhibited a high longitudinal piezoelectric constant d33,eff of 210 pC/N with estimated unconstrained d33 value of 560 pC/N very close to that in the corresponding bulks. Such excellent piezoelectric effect in the low-temperature sintered (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 thick films is comparable to the case of lead-based PZT thick films, and may be a promising application in lead-free microdevices such as piezoelectric microelectromechanical systems (MEMS).

  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. Investigation of the piezoelectric charge coefficient d33 of thick-film piezoelectric ceramics by varying poling and repoling conditions

    NASA Astrophysics Data System (ADS)

    Radzi, Muhamad Haffiz Mohd; Leong, Kok Swee

    2015-05-01

    Piezoelectric ceramics are commonly used in various sensing applications. In this paper, the effect of poling and repoling conditions on thick-film piezoelectric ceramics were investigated. The piezoelectric charge coefficient of the piezoelectric ceramics were measured with varying poling conditions, where the effect of changing poling temperature and electrical field on the d33 were analyzed. This was followed by investigating on the effect high applied electrical fields results in repolarization the alignment of the piezoelectric domain in the opposite direction. The temperature and electrical field dependence polarization of the thick-film piezoelectric ceramics were varied near to its Curie temperature between 50C to 250C and at a range of electrical field from 20 V (400 kV/mm) up to 200 V (4 MV/mm). It was found that the piezoelectric properties increases with increasing the poling electric field and poling temperature significantly. The maximum values of piezoelectric coefficient were obtained for the piezoelectric ceramics poled at the Curie temperature with high electric fields for 15 minutes. The aging behavior of the piezoelectric ceramics shows that piezoelectric charge coefficient d33 depends on the poling and repoling conditions.

  4. Preparation and dielectric properties of the lead-free BaFe1/2Nb1/2O3 ceramics obtained from mechanically triggered powder

    NASA Astrophysics Data System (ADS)

    Bochenek, Dariusz; Niemiec, Przemys?aw; Szafraniak-Wiza, Izabela; Adamczyk, Ma?gorzata; Skulski, Ryszard

    2015-10-01

    In the paper the influence of mechanical activation of the powder on the final dielectric properties lead-free Ba(Fe1/2Nb1/2)O3 (BFN) ceramic was examined. The BFN ceramics were obtained by 3-steps route. Firstly, the substrates were pre-homogenized in a planetary ball mill. Than, the powder was activated in vibratory mill (the shaker type SPEX 8000 Mixer Mill) for different duration between 25 h and 100 h. The influence of the milling time on the BFN powder was monitored by X-ray diffraction. The diffraction data confirmed that the milling process of the starting components is accompanied by partial synthesis of the BFN materials. The longer of the high-energy milling duration the powders results in increasing the amount of amorphous/nanocrystalline content. The mechanically activated materials were sintered in order to obtain the ceramic samples. During this temperature treatment the final crystallisation of the powder appeared what was confirmed by XRD studies. The performed dielectric measurements have revealed the reduction of the dielectric loss of the BFN ceramics compared to materials obtained by classic methods.

  5. Relaxorlike dielectric dynamics in the lead-free K0.5Na0.5NbO3-SrZrO3 ceramic system

    NASA Astrophysics Data System (ADS)

    Bobnar, Vid; Holc, Janez; Hrovat, Marko; Kosec, Marija

    2007-04-01

    We have detected a typical relaxor/glasslike dielectric response in the derived lead-free (1-x)K0.5Na0.5NbO3-(x)SrZrO3 ceramic system. In the compositional range 0.10?x?0.33, where solid solubility was observed, the system exhibits a broad dispersive dielectric maximum, a Vogel-Fulcher temperature dependence of the characteristic relaxation frequency, and a paraelectric-to-glass crossover in the temperature dependence of the dielectric nonlinearity. As the relatively high values of the dielectric constant, exceeding 5000 in the x =0.15 compound, are only weakly dependent on the frequency in the range of 20 Hz-1 MHz, and, furthermore, the history-dependent effects play only a minor role in comparison to some widely used lead-based relaxors, this environmentally friendly system seems to be very promising for a variety of applications.

  6. Research on micro-displacement driving technology based on piezoelectric ceramic

    NASA Astrophysics Data System (ADS)

    Hu, Bo; Tang, Xiaoping; Hu, Song; Yan, Wei; Hu, Zhicheng

    2012-10-01

    Piezoelectric ceramic driving power is one critical technology of achieving the piezoelectric ceramic nano-precision positioning, which has been widely used in precision manufacturing, optical instruments, aerospace and other fields. In this paper, piezoelectric ceramic driving power will be summarized on micro-displacement driving technical development and research. The domestic and overseas piezoelectric-driven ways will be compared and control model algorithms will be discussed. Describe the advantages and disadvantages of piezoelectric ceramic driving power in a different driving and control model, and then show the scope of application of driving power.

  7. 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

  8. Apodization process of piezoelectric ceramics for ultrasound transducers

    NASA Astrophysics Data System (ADS)

    Duarte, Mauricio G.; Nantes Button, Vera L. d. S.; Maia, Joaquim M.; Costa, Eduardo T.; Oliveira, Eduardo J. V.

    2003-05-01

    The objective of this work was to optimize the process of apodization of piezoelectric ceramic discs, looking for the better relationship between oil bath temperature and time of electrical field application. The apodization was performed to reduce the diffraction in the acoustic field generated by ultrasonic transducers. We used 12.7mm diameter and 1mm thickness PZT-5A discs. The apodization field (2kV/mm thickness) has been shaped by a 5mm radius spherical electrode throughout the apodization processes we have used. The apodized ceramic discs which showed electromechanical coupling coefficient value, for the thickness mode of vibration, equal or larger than 0.37, were considered well apodized. We used initial oil bath temperatures from 120C to 250C and the electric field was applied for periods of at least 2 minutes to up to 4 hours. The results showed that if the poling electric field was applied to the piezoelectric ceramic even before the oil was heated, we obtained larger piezoelectric coupling coefficients; in higher temperatures (250C) this was not necessary. We concluded that using higher temperatures (250C) it was possible to reduce the apodization process, with satisfactory results, from 4-5 hours to 2 minutes. Ultrasound transducers were built with apodized ceramics and their acoustic fields showed larger depth of field relative to non apodized ones.

  9. 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.

  10. 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 ?S and ?T, 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

  11. 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 ?S and ?T, 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.

  12. 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.

  13. 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.

  14. Major contributor to the large piezoelectric response in (1 - x)Ba(Zr0.2Ti0.8)O3 - x(Ba0.7Ca0.3)TiO3 ceramics: Domain wall motion

    NASA Astrophysics Data System (ADS)

    Gao, Jinghui; Hu, Xinghao; Zhang, Le; Li, Fei; Zhang, Lixue; Wang, Yu; Hao, Yanshuang; Zhong, Lisheng; Ren, Xiaobing

    2014-06-01

    The piezoelectric activity of lead-free Ba(Zr0.2Ti0.8)O3-x(Ba0.7Ca0.3)TiO3 (BZT-xBCT) ceramics has been investigated as a function of composition by using Rayleigh analysis under subswitching-electric-field in combination with large-electric-field strain measurement. The result shows that the intrinsic piezoelectric response exhibits peak values in the vicinity of composition-induced R (rhombohedral)-MPB (morphotropic phase boundary) and MPB-T (tetragonal) phase transitions, but being much less than total d33 value. On the other hand, the extrinsic piezoelectric response, especially the one associated with reversible domain wall motion, has been greatly enhanced in the phase instability regime. Our results indicate that the extrinsic piezoelectric activity is the major contributor to the high piezoelectricity in BZT-xBCT ceramics.

  15. 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.

  16. 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.

  17. Polar nanoregions and dielectric properties in high-strain lead-free 0.93(Bi1/2Na1/2)TiO3-0.07BaTiO3 piezoelectric single crystals

    NASA Astrophysics Data System (ADS)

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

    2014-01-01

    A structural coexistence of rhombohedral (R) and tetragonal (T) phases has been revealed in the (001)c-cut lead-free 0.93(Bi1/2Na1/2)TiO3-0.07BaTiO3 (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 (?') of dielectric permittivity begins to deviates from the Curie-Weiss equation, ?' = C/(T - To), from the Burns temperature TB = 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 d33 exhibits a rapid increase at E = 15-20 kV/cm and reaches a maximum of d33 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.

  18. High piezoelectricity due to multiphase coexistence in low-temperature sintered (Ba,Ca)(Ti,Sn)O3-CuOx ceramics

    NASA Astrophysics Data System (ADS)

    Zhou, Peng-Fei; Zhang, Bo-Ping; Zhao, Lei; Zhao, Xiao-Kun; Zhu, Li-Feng; Cheng, Li-Qian; Li, Jing-Feng

    2013-10-01

    Ultrahigh piezoelectric constant (d33 = 683 pC/N) and converse piezoelectric coefficient (dS/dE = 1257 pm/V) were observed in CuO-doped lead-free (Ba,Ca)(Ti,Sn)O3 ceramics at an optimal composition fabricated by a conventional sintering method at a low temperature 1250 C. Since all samples showed a pure perovskite structure with coexisting multiphases including cubic, tetragonal, orthorhombic, and rhombohedral phases around two converged triple points, a good compositional stability of high piezoelectricity along with a high d33 and dS/dE over 600 pC/N and 1000 pm/V was achieved within a wide compositional region (1.0 ? x ? 3.0) regardless of the CuO content (x).

  19. 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.

  20. (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

  1. Enhancing Piezoelectric Performance of CaBi2Nb2O9 Ceramics Through Microstructure Control

    NASA Astrophysics Data System (ADS)

    Chen, Huanbei; Zhai, Jiwei

    2012-08-01

    Calcium bismuth niobate (CaBi2Nb2O9, CBN) is a high-Curie-temperature ( T C) piezoelectric material with relatively poor piezoelectric performance. Attempts were made to enhance the piezoelectric and direct-current (DC) resistive properties of CBN ceramics by increasing their density and controlling their microstructural texture, which were achieved by combining the templated grain growth and hot pressing methods. The modified CBN ceramics with 97.5% relative density and 90.5% Lotgering factor had much higher piezoelectric constant ( d 33 = 20 pC/N) than those prepared by the normal sintering process ( d 33 = 6 pC/N). High-temperature alternating-current (AC) impedance spectroscopy of the CBN ceramics was measured by using an impedance/gain-phase analyzer. Their electrical resistivity was approximately 6.5 104 ? cm at 600C. Therefore, CBN ceramics can be used for high-temperature piezoelectric applications.

  2. 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., d33390 pC/N, kp0.45, Smax0.2%, and TC250 C) were simultaneously induced. We think that this may provide a direction of designing high-performance (K,Na)NbO3-based ceramics.

  3. 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.

  4. Piezoelectric and Ferromagnetic Properties of PMN-PFN Ferroelectromagnetic Ceramics

    NASA Astrophysics Data System (ADS)

    Portelles, Jorge; Siqueiros, Jess M.; Font, Reynaldo

    2001-03-01

    The induced piezoelectricity and magnetic properties of the (1-x)Pb(Mg_1/3Nb_2/3)O_3-xPb(Fe_1/2Nb_1/2)O_3, ((1-x)PMN-xPFN, x= 0.1, 0.2, 0.3, 0.4, 1) ferroelectromagnetic ceramics have been investigated. The effect of the variation of Fe content on the electromechanical properties of the ceramic is analyzed observing that the electromechanical efficiency decreases when either the applied external electric field is increased or the concentration of the ferroactive Fe cation is decreased. The dependence of the magnetic characteristics such as the specific magnetization (?) and magnetic susceptibility (\\chi) were investigated using thermo-magnetic analysis. The magnetic behavior obeys a weak ferromagnetism law. A regular decrease of the ? and \\chi values as the amount of Fe in the (1-x)PMN-xPFN is decreased is observed. A study of the influence of the Fe cations on the dielectric and magnetic properties is used to analyze the coupling between the ferroelectric and the antiferromagnetic order in the ceramic.

  5. 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.

  6. Sound transmission control through rectangular plate by using piezoelectric ceramics as actuators and sensors

    NASA Astrophysics Data System (ADS)

    Akishita, Sadao; Mitani, Yu-Ichiro; Miyaguchi, Hiroshi

    1994-05-01

    This paper describes the active control of sound transmission through a clamped rectangular plate by using piezoelectric ceramics as actuators and sensors. Optimal use of the piezoelectric ceramic actuator is investigated theoretically by using the transfer function from incident sound pressure to radiated sound pressure and the first order approximated damping ratio. By applying direct velocity feedback control by five pieces of the actuators, substantial reduction of peak level at eigen mode frequency is obtained below the frequency range of about 1500 Hz. The use of piezoelectric ceramics as actuators and as sensors fails in the direct velocity feedback control experiment, but has potential for the direct position feedback control experiment.

  7. 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.

  8. 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.

  9. 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.

  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. 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 (?) 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 (?=0.22 K mm/kV).

  12. Intelligent motion control for linear piezoelectric ceramic motor drive.

    PubMed

    Wai, Rong-Jong; Lee, Jeng-Dao

    2004-10-01

    Since the dynamic characteristics of a linear piezoelectric ceramic motor (LPCM) are highly nonlinear and time varying, it is difficult to design a suitable motor drive and position controller that realizes accurate position control at all time. This study investigates a double-inductance double-capacitance (LLCC) resonant driving circuit and a sliding-mode fuzzy-neural-network control (SMFNNC) system for the motion control of an LPCM. First, the motor structure and LLCC driving circuit of an LPCM are introduced. The LLCC resonant inverter is designed to operate at an optimal switching frequency such that the output voltage will not be influenced by the variation of quality factor. Moreover, a SMFNNC system is designed to achieve favorable tracking performance without precise dynamic models being controlled. All adaptive learning algorithms in the SMFNNC system are derived in the sense of Lyapunov stability analysis, so that system-tracking stability can be guaranteed in the closed-loop system. The effectiveness of the proposed driving circuit and control system is verified by experimental results. PMID:15503505

  13. 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 900C-1150C. 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 1100C for pure BNT ceramic and 1000C 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.

  14. 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.

  15. Shear-Mode Piezoelectric Properties of KNbO3-Based Ferroelectric Ceramics

    NASA Astrophysics Data System (ADS)

    Hikita, Kouhei; Hiruma, Yuji; Nagata, Hajime; Takenaka, Tadashi

    2009-07-01

    Potassium niobate, KNbO3, (KN)-based ceramics were prepared by a modified conventional ceramic fabrication process to characterize their piezoelectric properties. The KN-MnCO3 0.1 wt % (KN-Mn0.1) ceramic used in this study showed a high density ratio >96% and a high resistivity, ?, of about 1013 ?cm without deliquescent properties. The shear mode of the KN-Mn0.1 ceramic showed excellent resonance and antiresonance characteristics with tiny spurious peaks upon optimization of the sample dimensions. The electromechanical coupling factor, k15, and piezoelectric strain constant, d15, of KN-Mn0.1 showed relatively large values of 0.55 and 207 pC/N, respectively. The shear-mode vibration of KN-based ceramics appears to be a very promising candidate for actuators and high-power applications.

  16. 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.

  17. 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.

  18. 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.

  19. Nonlinear piezoelectricity in PZT ceramics for generating ultrasonic phase conjugate waves

    PubMed

    Yamamoto; Kokubo; Sakai; Takagi

    2000-03-01

    We have succeeded in the generation of acoustic phase conjugate waves with nonlinear PZT piezoelectric ceramics and applied them to ultrasonic imaging systems. Our aim is to make a phase conjugator with 100% efficiency. For this purpose, it is important to clarify the mechanism of acoustic phase conjugation through nonlinear piezoelectricity. The process is explained by the parametric interaction via the third-order nonlinear piezoelectricity between the incident acoustic wave at angular frequency omega and the pump electric field at 2 omega. We solved the coupling equations including the third-ordered nonlinear piezoelectricity and theoretically derived the amplitude efficiency of the acoustic phase conjugation. We compared the efficiencies between the theoretical and experimental values for PZT ceramics with eight different compositions. Pb[(Zn1/3Nb2/3)(1 - x)Tix]O3 (X = 0.09, PZNT91/9) piezoelectric single crystals have been investigated for high-performance ultrasonic transducer application, because these have large piezoelectric constants, high electrical-mechanical coupling factors and high dielectric constants. We found that they have third-order nonlinear piezoelectric constants much larger than PZT and are hopeful that the material as a phase conjugator has over 100% efficiency. PMID:10829782

  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. 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.

  2. 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.

  3. Structural, ferroelectric and magnetic study of lead free (Na0.5Bi0.5)1-xLaxTi0.988Fe0.012O3 (x=0,0.01,0.03,0.05) ceramic

    NASA Astrophysics Data System (ADS)

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

    2015-05-01

    Lead free (Na0.5Bi0.5)1-xLaxTi0.988Fe0.012O3 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-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 (Na0.5Bi0.5)1-xLaxTi0.988Fe0.012O3 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.

  4. 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.

  5. 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 Mssbauer, 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 Mssbauer 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.

  6. 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.

  7. Composition-Driven Phase Boundary and Piezoelectricity in Potassium-Sodium Niobate-Based Ceramics.

    PubMed

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

    2015-09-16

    The piezoelectricity of (K,Na)NbO3 ceramics strongly depends on the phase boundary types as well as the doped compositions. Here, we systematically studied the relationships between the compositions and phase boundary types in (K,Na) (Nb,Sb)O3-Bi0.5Na0.5AO3 (KNNS-BNA, A=Hf, Zr, Ti, Sn) ceramics; then their piezoelectricity can be readily modified. Their phase boundary types are determined by the doped elements. A rhombohedral-tetragonal (R-T) phase boundary can be driven in the compositions range of 0.035?BNH?0.040 and 0.035?BNZ?0.045; an orthorhombic-tetragonal (O-T) phase boundary is formed in the composition range of 0.005?BNT?0.02; and a pure O phase can be only observed regardless of BNS content (?0.01). In addition, the phase boundary types strongly affect their corresponding piezoelectricities. A larger d33 (?440-450 pC/N) and a higher d33* (?742-834 pm/V) can be attained in KNNS-BNA (A=Zr and Hf) ceramics due to the involvement of R-T phase boundary, and unfortunately KNNS-BNA (A=Sn and Ti) ceramics possess a relatively poor piezoelectricity (d33?200 and d33*<600 pm/V) due to the involvement of other phase structures (O-T or O). In addition, the underlying physical mechanisms for the relationships between piezoelectricity and phase boundary types were also discussed. We believe that comprehensive research can design more excellent ceramic systems concerning potassium-sodium niobate. PMID:26302094

  8. Nonlinear piezoelectric behavior of ceramic bending mode actuators under strong electric fields

    NASA Astrophysics Data System (ADS)

    Wang, Qing-Ming; Zhang, Qiming; Xu, Baomin; Liu, Ruibin; Cross, L. Eric

    1999-09-01

    The nonlinear electromechanical behavior of cantilevered piezoelectric ceramic bimorph, unimorph, and reduced and internally biased oxide wafer actuators is studied in a wide electric field and frequency range. It is found that under quasistatic condition, linear relationships between actuator tip displacement-electric field, and blocking force-electric field are only valid under weak field driving. With increasing the driving field, electromechanical nonlinearity begins to contribute significantly to the actuator performance because of ferroelectric hysteresis behavior associated with piezoelectric lead zirconate titanate (PZT)-type ceramic materials. The bending resonance frequencies of all these actuators vary with the magnitude of the electric field. The decrease of resonance frequency with electric field is explained by the increase of elastic compliance of PZT ceramic due to elastic nonlinearity. Mechanical quality factors of the actuators also depend on the magnitude of electric field strength. No significant temperature increase is observed when actuators are driven near resonance frequency under high electric field.

  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. TECHNICAL NOTE: Dielectric and piezoelectric properties of piezoelectric ceramic sulphoaluminate cement composites

    NASA Astrophysics Data System (ADS)

    Cheng, Xin; Huang, Shifeng; Chang, Jun; Lu, Lingchao; Liu, Futian; Ye, Zengmao; Wang, Shoude

    2005-10-01

    Using cement as the matrix of piezoelectric smart composites can solve the problem of mismatch of smart composites and concrete structure in civil engineering. 0 3 cement based piezoelectric composites were fabricated by a compression technique using PMN and sulphoaluminate cement as raw materials. The influence of the PMN content on the dielectric and piezoelectric properties of the composites was investigated. The temperature dependence of the dielectric properties of the composites was discussed in detail. The results indicate that the dielectric constants are almost constant in the temperature range from -30 to 50 C, which shows excellent dielectric temperature stability. With increasing PMN content, the piezoelectric and dielectric properties of the composites increase. The theoretical values of the dielectric constants show good agreement with the experimental values for the composites.

  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. 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

  13. 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.

  14. 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.

  15. A procedure for the efficient selection of piezoelectric ceramics constituting high-power ultrasonic transducers.

    PubMed

    Chacn, D; Rodrguez-Corral, G; Gaete-Garretn, L; Riera-Franco de Sarabia, E; Gallego-Jurez, J A

    2006-12-22

    The most characteristic narrow-band transducer structure for high-power ultrasonic applications is the well known piezoelectric sandwich which is reminiscent of the Langevin transducer. Such structure is generally used jointly with other components in the construction of industrial high-power transducers. One of the main objectives in the design and construction of such high-power transducers is to minimize energy losses. To that purpose the selection of the piezoelectric ceramic rings forming the sandwich requires clear and specific criteria. This paper deals with a numerical and experimental procedure for the accurate selection of the piezoelectric rings constituting high-power transducers, based on the analysis of the mechanical Q, the frequency and the resonance curve. The procedure was experimentally checked by constructing and characterizing several transducer structures. PMID:16797649

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. Piezoelectric, dielectric, and ferroelectric properties of 0-3 ceramic/cement composites

    NASA Astrophysics Data System (ADS)

    Xin, Cheng; Shifeng, Huang; Jun, Chang; Zongjin, Li

    2007-05-01

    The sulphoaluminate cement and a piezoelectric ceramic, 0.08Pb(Li1/4Nb3/4)O3.0.47PbTiO3.0.45PbZrO3[P(LN)ZT], were used to fabricate 0-3 cement based piezoelectric composites. The piezoelectric, dielectric, and ferroelectric properties of the composites were mainly investigated. The results indicate that the piezoelectric strain factor d33 increases as the P(LN)ZT volume fraction increases, which follows the cube model well. The dielectric constant ?x and dielectric loss tan ? show similar trends with the d33. In the frequency range of 40-100 kHz, the dielectric constants of the composites decrease sharply, which is mainly attributed to interfacial polarization in the composite. Above 200 kHz, the cement-based piezoelectric composites exhibit good dielectric-frequency stability. Hysteresis measurements indicate that the composites exhibit typical ferroelectric hysteresis loops at room temperature. The remanent polarization Pr and the coercive field Ec of the composites increase as the P(LN)ZT volume fraction increases. Meanwhile, the remnant polarizations Pr shows little asymmetric characterization.

  5. 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)

  6. 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

  7. 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)? cm), good piezoelectricity (d33 = 10.2 pC N(-1)), high Curie temperature (TC = 814 C), strong ferroelectricity (Pr = 9.03 ?C 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

  8. Simultaneous measurement of electro-optical and converse-piezoelectric coefficients of PMN-PT ceramics.

    PubMed

    Xiao, Pingping; Wang, Xianping; Sun, Jingjing; Huang, Meizhen; Chen, Xianfeng; Cao, Zhuangqi

    2012-06-18

    A new scheme is proposed to measure the electro-optical (EO) and converse-piezoelectric (CPE) coefficients of the PMN-PT ceramics simultaneously, in which the PMN-PT ceramics acts as the guiding layer of a symmetrical metal-cladding waveguide. As the applied electric field exerts on the waveguide, the effective refractive index (RI) (or synchronous angle) can be effectively tuned from a selected mode to another adjacent mode owing to the high sensitivity and the small spacing of the ultra-high order modes. Subsequently, a correlation between EO and CPE coefficients is established. With this correlation and the measurement of the effective RI change to the applied voltage, the quadratic EO and CPE coefficients of PMN-PT ceramics are obtained simultaneously. The obtained results are further checked by fitting the variations of effective RI to a quadratic function. Our measurement method can be extended to a wide range of other materials. PMID:22714448

  9. 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.

  10. 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.

  11. Mechanical properties of metal-core piezoelectric fiber

    NASA Astrophysics Data System (ADS)

    Sato, Hiroshi; Nagamine, Masaru

    2005-05-01

    In the previous conference, we produced a new metal core-containing piezoelectric ceramics fiber by the hydrothermal method and extrusion method. The insertion of metal core is significant in view of its greater strength than ceramics materials, and electrodes are not required in the fiber's sensor and actuator applications. A new smart board was designed by mounting these piezoelectric fibers onto the surface of a CFRP composite. After that, this board is able to use this board to a sensor, actuator and vibration suppression. In this paper, we measured s mechanical properties of metal core piezoelectric fiber. We examined the tension test of a piezo-electric fiber, and measured the Young's modulus and breaking strength. Moreover, the expansion in the fiber unit was measured, and the displacement of the direction of d31 was measured. In addition, a piezo-electric fiber that used lead free material (BNT-BT-BKT) to correspond to environmental problems in recent years was made.

  12. Photoluminescence, ferroelectric, dielectric and piezoelectric properties of Er-doped BNT-BT multifunctional ceramics

    NASA Astrophysics Data System (ADS)

    Lau, Chi Man; Xu, Xiao Wu; Kwok, K. W.

    2015-05-01

    0.93(Bi0.5-x/0.93Erx/0.93Na0.5)TiO3-0.07BaTiO3 photoluminescent ceramics have been prepared by a conventional ceramic fabrication technique and their photoluminescence, ferroelectric, dielectric and piezoelectric properties have been studied. Under an excitation of 980 nm, the ceramics exhibit visible up-conversion luminescent emissions at 532 nm (green), 540 nm (green) and 600 nm (red), as well as broadband down-conversion luminescent emissions in near-infrared (1.44-1.66 ?m) and mid-infrared (2.62-2.84 ?m) regions. The quenching concentration for the ceramics is high, about 6%, and both the visible and invisible emissions are very strong. Among the emissions, the photoluminescence intensity of the red emission band increases most significantly by more than 47 times as the Er-concentration increases from 0.005 to 0.07. As a result, the Commission Internationale de L'Eclairage chromaticity coordinates shift from (0.29, 0.69) to (0.49, 0.50), and the emission color changes from green to yellowish green. Owing to the establishment of a dynamic circulatory energy process at high Er-concentrations, the photoluminescence intensity of the mid-infrared emission increases significantly by more than 4 times at the expense of the near-infrared emission. Together with the good ferroelectric and piezoelectric properties, the ceramics should be promising candidates for multifunctional optoelectronic applications.

  13. Dielectric and piezoelectric properties in the lead-free system Na0.5K0.5NbO3-BiScO3-LiTaO3.

    PubMed

    Zhu, Fangyuan; Ward, Michael B; Comyn, Tim P; Bell, Andrew J; Milne, Steven J

    2011-09-01

    Phase relations, dielectric and piezoelectric properties are reported for the ternary system 98%[(1 - x) (Na(0.5)K(0.5)NbO(3))-x(LiTaO(3))]-2%[BiScO(3)] for compositions x ? 10 mol% LiTaO(3). The phase content at room-temperature changed from mixed phase, monoclinic + tetragonal, for unmodified 98%(Na(0.5)K(0.5)NbO(3))-2%(BiScO(3)), to tetragonal phase for compositions >2 mol% LiTaO(3). Curie peaks at 360 to 370C were observed for all compositions, but peaks became diffuse at x ? 3 mol%, and two dielectric peaks, at 370 and 470C, were observed for 5 mol% LiTaO(3). Phase segregation, and finite size affects associated with the core-shell structure, account for the occurrence of two dielectric peaks in 5 mol% LiTaO(3), and diffuse dielectric behavior. The value of d(33) piezoelectric charge coefficient increased from ~160 pC/N for 0 mol% LiTaO(3) to 205 to 214 pC/N for 1 to 2 mol% LiTaO3 solid solutions, before falling sharply at 3 mol% LiTaO(3). TEM-EDX analysis revealed core-shell grain structures with segregation of Bi, Sc, and Ta in the outer ~100-nm shell of the 5 mol% LT sample. PMID:21937312

  14. The piezoelectric effect in Na0.5Bi0.5TiO3 ceramics

    NASA Astrophysics Data System (ADS)

    Roleder, K.; Franke, I.; Glazer, A. M.; Thomas, P. A.; Miga, S.; Suchanicz, J.

    2002-06-01

    Piezoelectric properties of Na0.5Bi0.5TiO3 ceramics have been investigated over a broad temperature range using a resonance technique. The thermal behaviours of the piezoelectric tensor coefficients d31, d33 and d15 confirm that there is a distinct phase transformation at 200 C. For the first time it has been found that a piezoelectric signal connected with the tensor component d33 is observed up to 280 C. This corresponds to earlier neutron and x-ray diffraction data on the point of transition from rhombohedral to tetragonal symmetry.

  15. Roles of Li and Ta in Pb-free piezoelectric (Na,K)NbO3 ceramics

    NASA Astrophysics Data System (ADS)

    Sung, Y. S.

    2014-10-01

    Piezoelectric coefficient (d33) of (Na,K)NbO3 (NKN) is enhanced not only at its morphotropic phase boundary (MPB) composition but also enhanced at its polymorphic phase transition (PPT) temperature between orthorhombic and tetragonal phases (TO-T). Thus, for NKN-based ceramics, even higher d33 could be obtained if both MPB and PPT are simultaneously optimized. This temperature as well as composition dependence of piezoelectric properties of NKN-based ceramics requires a systematic approach that differentiates factors for MPB and PPT. In this paper, the roles of Li and Ta known to affect d33 and TO-T were identified in relation with lattice parameters.

  16. 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.

  17. Microstructures, dielectric, and piezoelectric properties of W/Cr co-doped Bi4Ti3O12 ceramics

    NASA Astrophysics Data System (ADS)

    Chen, Yu; Liang, Dayun; Wang, Qingyuan; Zhu, Jianguo

    2014-08-01

    W/Cr co-doped Bi4Ti3O12 (BTWC) ceramics {Bi4Ti3-xWxO12 + x + 0.2 wt. % Cr2O3 (x = 0-0.1)} with a high piezoelectricity were prepared by a conventional ceramic process, and effects of W/Cr dopant on the microstructures, dielectric, and piezoelectric properties of ceramics were explored. It is found that W6+ modified the grain morphology and size of ceramics, promoting the forming of the regular schistose grains with a size of 10 ?m in the ceramic at x = 0.05. BTWC ceramics showed a continuous decrease in Tc and a gradual increase in ?r with the increasing W doping content. While the hard-doping of Cr2O3 decreased, the TK? and tan ? of ceramics available. All the ceramics keep the nature of first-order transition and displacive ferroelectrics. The d33 and kp of BTWC ceramics were remarkably improved by the soft-doping of W6+. Excellent electrical properties (e.g., Tc = 638 C, ?r = 146, tan ? = 0.56%, TK? (500 C) = 1.30 10-3/ C, ? (500 C) = 4.08 10-5 s, d33 = 28 pC/N, and kp = 6.17%) have been achieved in Bi4Ti2.95W0.05O12.05 + 0.2 wt. % Cr2O3 ceramic. Such a material can be a promising candidate for high-temperature piezoelectric applications.

  18. Phase diagram and structure-property relationships in the lead-free piezoelectric system: Na0.5K0.5NbO3-LiTaO3.

    PubMed

    Skidmore, Thomas A; Comyn, Timothy P; Bell, Andrew J; Zhu, Fangyuan; Milne, Steven J

    2011-09-01

    A phase-diagram for the Na(0.5)K(0.5)NbO(3)-LiTaO(3) solid solution series (NKN-LT) is presented for compositions ? 10 mol% LT, based on the combined results of temperaturevariable X-ray powder diffraction and dielectric measurements. In addition to the reported orthorhombic and tetragonal polymorphs of NKN-LT, a monoclinic phase is revealed. Changes to electrical properties as a function of LT substitution are correlated to phase content. Increasing the LT content from 5 to 7 mol% LT led to improved temperature stability of piezoelectric properties because of the avoidance of the monoclinic-tetragonal polymorphic phase transition during thermal cycling (at >25C). For 7 mol% LT samples: d(33) = 200 pC/N; T(c) = 440C; ?(r) = 550 and tan ? = 0.02 (at 20C). Modification of this composition by solid solution with BiScO(3) led to a decrease in d(33) values. Transmission electron microscopy of a sample of 0.95[0.93 NKN-0.07LT]-0.05BiScO(3) indicated a core-shell grain structure which led to temperature-stable dielectric properties. PMID:21937313

  19. 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.

  20. 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

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

    PubMed Central

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

    2013-01-01

    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 320 MHz. The center frequency of > 300 MHz 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 ?6 dB 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 ?60 dB. In addition to the pulse-echo measurement, a 6-?m tungsten wire phantom was also imaged with a 205 MHz transducer to demonstrate the imaging capability. The measured ?6 dB 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

  2. Phase boundary at x =0.03 and its anomalous influence on the structure and properties in the lead-free piezoelectric (1 -x ) N a1 /2B i1 /2Ti O3-(x ) BaTi O3

    NASA Astrophysics Data System (ADS)

    Rao, Badari Narayana; Avdeev, Maxim; Kennedy, Brendan; Ranjan, Rajeev

    2015-12-01

    The complexity associated with local structures continues to pose challenges with regard to the understanding of the structure-property relationship in N a1 /2B i1 /2Ti O3 -based lead-free piezoceramics. (1 -x ) N a1 /2B i1 /2Ti O3-(x ) BaTi O3 is an extensively studied system because of its interesting piezoelectric properties. Recently, a room temperature phase boundary was reported at x =0.03 in this system [Ma et al., Adv. Funct. Mater. 23, 5261 (2013), 10.1002/adfm.201300640]. In the present work we have examined this subtle phase boundary using x-ray diffraction, neutron diffraction, dielectric measurements as a function of composition (x <0.06 ) , temperature, and electric field. Our results show that this boundary separates an R 3 c +C c -like structural state for x <0.03 from an R 3 c + cubiclike structural state for 0.03 ?x ?0.05 in the unpoled specimens. This phase boundary is characterized by an anomalous reduction in the depolarization temperature, and a suppression of the tetragonal distortion of the high temperature P 4 b m phase. Our results also provide the clue to understand the pathway leading to the cubiclike structure of the critical composition x =0.06 , known for its highest piezoelectric response.

  3. Growth and electrical properties of 0.88Na0.5Bi0.5TiO3-0.12K0.5Bi0.5TiO3 lead-free piezoelectric single crystal

    NASA Astrophysics Data System (ADS)

    Sun, Renbing; Zhang, Haiwu; Wang, Jinzhi; Wang, Fang; Fang, Bijun; Zhao, Xiangyong; Luo, Haosu

    2013-05-01

    A large-size 0.88Na0.5Bi0.5TiO3-0.12K0.5Bi0.5TiO3 lead-free piezoelectric single crystal with dimensions of ?30 mm 10 mm was successfully grown by the top-seeded solution growth method. X-ray powder diffraction measurement showed that the as-grown crystal possesses a rhombohedral perovskite structure at room temperature. The temperature dependence of dielectric constant and loss, polarization hysteresis loop, electric-field-induced strain, and the electromechanical coupling property were investigated for the <100>-oriented as-grown crystal. The remanent polarization P r, the piezoelectric constant d 33, and the electromechanical coupling coefficient k t at room temperature are 13.8 pC/cm2, 205 pC/N, and 51 %, respectively. The maximum strain of 0.23 % was obtained under 30 kV/cm. The temperature dependence of k t demonstrated a relatively stable thermal electromechanical coupling property over the temperature range of 20-150 C.

  4. 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.

  5. 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.

  6. 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

  7. Depolarization field effect on dielectric and piezoelectric properties of particulate ferroelectric ceramic-polymer composites

    NASA Astrophysics Data System (ADS)

    Ma, Fengde D.; Wang, Yu U.

    2015-03-01

    The effects of depolarization field on the dielectric and piezoelectric properties of ferroelectric ceramic particle-filled polymer-matrix composites are investigated at the underlying domain level. Phase field modeling and simulation reveals that the macroscopic properties of the composites are dominated by depolarization field effect, which depends on the arrangement and alignment rather than the size or internal grain structure of the ferroelectric particulates. It is found that 0-3 particulate composites with random dispersion of ferroelectric particles behave essentially like linear dielectric rather than ferroelectric materials, and domain-level analysis reveals the physical mechanism for lack of domain switching or hysteresis as attributed to strong depolarization effect. Thus, without effective reduction or elimination of the depolarization field, the composites cannot benefit from the functional fillers regardless of their superior properties. In order to exhibit the desired ferroelectric behaviors, it necessitates continuous ferroelectric phase connectivity in the composites.

  8. 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.

  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. Mechanical characterization of sintered piezo-electric ceramic material using scanning acoustic microscope.

    PubMed

    Habib, A; Shelke, A; Vogel, M; Pietsch, U; Jiang, Xin; Kundu, T

    2012-12-01

    Lead Zirconate Titanate (PZT) is a piezo-electric ceramic material that needs to be characterized for its potential use in microelectronics. Energy dispersive X-ray analysis (EDX) is conducted to determine the chemical composition of the PZT ceramics. The scanning electron microscope (SEM) is performed to study the surface morphology, grain structure and grain boundaries. The SEM image helps us to understand the surface wave propagation and scattering phenomena by the PZT and the reason for its anisotropy and inhomogeneity due to the grain structure. In this paper scanning acoustic microscopy at 100 MHz excitation frequency is conducted for determining mechanical properties of PZT. Earlier works reported only the longitudinal wave speed in PZT while in this paper longitudinal, shear and surface acoustic wave speeds of sintered PZT are measured from its acoustic material signature (AMS) curves, also known as V(z) curves. AMS or V(z) curve is the variation of the output voltage as a function of the distance between the acoustic lens focal point and the reflecting surface. The average velocities of longitudinal, shear and surface acoustic waves in a PZT specimen are determined from its V(z) curve generated at 100 MHz excitation frequency and found to be over 5000 m/s, over 3000 m/s and between 2500 and 3000 m/s, respectively. From these velocities all elastic constants of the specimen are obtained. PMID:22989949

  11. 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.

  12. Preparation and characterization of yBiGaO(3)-(1-x-y)BiScO(3)-xPbTiO(3) piezoelectric ceramics.

    PubMed

    Jiang, Yihang; Qin, Baoquan; Chen, Yi; Huang, Wei; Zhao, Yi; Jiang, Yuzhi; Xiao, Dingquan; Zhu, Jianguo

    2007-12-01

    The ternary system of yBiGaO(3)-(1-x-y)BiScO(3)-xPbTiO(3) (BGS-PT) ceramics was prepared by using conventional mixing oxide processing. X-ray diffraction analysis revealed that the BGS-PT ceramics showed the perovskite structure. The Curie temperature (TC) of BGSPT ceramics was found to increase with increasing BiGaO3 content. However, a larger BiGaO3 content led to sharply decreased piezoelectric properties, and the secondary phase was formed in the BGS-PT system. BGS-PT ceramics with x = 0.56, y = 0.19 showed a high Curie temperature T(C) and a large piezoelectric constant d(33) of 501??C and 152 pC/N, respectively. The high T(C) of BGS-PT ceramics with usable piezoelectric properties suggests future high-temperature applications. PMID:18276546

  13. 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.

  14. The effect of low-fluence neutron irradiation on silver-electroded lead-zirconate-titanate piezoelectric ceramics

    NASA Astrophysics Data System (ADS)

    Broomfield, G. H.

    1980-06-01

    The properties of several different versions of near equi-molar proportioned lead-zirconate-titanate ceramic piezoelectric plates were measured after irradiation for up to 48 h in an MTR hollow fuel element. The irradiation temperature was 180 50C and the maximum fluences 3.5 10 19 thermal and 1.4 10 19 fission neutrons/cm 2. The irradiation decreased the capacitance, increased the thickness-mode resonant frequencies and decreased the elevated temperature electromechanical coupling in all of the samples tested. The effects are considered to be due to a change in the electrode bonding and a reduction in the polarisation of the ceramic.

  15. 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.; Graa, 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 303400 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 ferroelectricparaelectric 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 rhombohedraltetragonal phases is a promising candidate for lead-free ferroelectric applications.

  16. 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 ?m 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 ?m displacement; 13.02 kHz and 2.7 ?m 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

  17. 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-Rodrguez, 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 ?m. 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, ? p, s 11, d 31 and g 31 are determined and compared to those of commercial PZT ceramics.

  18. 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-Rodrguez, 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 ?m. 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, ? p, s 11, d 31 and g 31 are determined and compared to those of commercial PZT ceramics.

  19. 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 ?C/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.

  20. 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.

  1. 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.

  2. Fabrication and characterization of thick-film piezoelectric lead zirconate titanate ceramic resonators by tape-casting.

    PubMed

    Qin, Lifeng; Sun, Yingying; Wang, Qing-Ming; Zhong, Youliang; Ou, Ming; Jiang, Zhishui; Tian, Wei

    2012-12-01

    In this paper, thick-film piezoelectric lead zirconate titanate (PZT) ceramic resonators with thicknesses down to tens of micrometers have been fabricated by tape-casting processing. PZT ceramic resonators with composition near the morphotropic phase boundary and with different dopants added were prepared for piezoelectric transducer applications. Material property characterization for these thick-film PZT resonators is essential for device design and applications. For the property characterization, a recently developed normalized electrical impedance spectrum method was used to determine the electromechanical coefficient and the complex piezoelectric, elastic, and dielectric coefficients from the electrical measurement of resonators using thick films. In this work, nine PZT thick-film resonators have been fabricated and characterized, and two different types of resonators, namely thickness longitudinal and transverse modes, were used for material property characterization. The results were compared with those determined by the IEEE standard method, and they agreed well. It was found that depending on the PZT formulation and dopants, the relative permittivities ?(T)(33)/?(0) measured at 2 kHz for these thick-films are in the range of 1527 to 4829, piezoelectric stress constants (e(33) in the range of 15 to 26 C/m(2), piezoelectric strain constants (d(31)) in the range of -169 10(-12) C/N to -314 10(-12) C/N, electromechanical coupling coefficients (k(t)) in the range of 0.48 to 0.53, and k(31) in the range of 0.35 to 0.38. The characterization results shows tape-casting processing can be used to fabricate high-quality PZT thick-film resonators, and the extracted material constants can be used to for device design and application. PMID:23221230

  3. 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

  4. 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.

  5. Recurrent fuzzy neural network control for piezoelectric ceramic linear ultrasonic motor drive.

    PubMed

    Lin, F J; Wai, R J; Shyu, K K; Liu, T M

    2001-07-01

    In this study, a recurrent fuzzy neural network (RFNN) controller is proposed to control a piezoelectric ceramic linear ultrasonic motor (LUSM) drive system to track periodic reference trajectories with robust control performance. First, the structure and operating principle of the LUSM are described in detail. Second, because the dynamic characteristics of the LUSM are nonlinear and the precise dynamic model is difficult to obtain, a RFNN is proposed to control the position of the moving table of the LUSM to achieve high precision position control with robustness. The back propagation algorithm is used to train the RFNN on-line. Moreover, to guarantee the convergence of tracking error for periodic commands tracking, analytical methods based on a discrete-type Lyapunov function are proposed to determine the varied learning rates of the RFNN. Then, the RFNN is implemented in a PC-based computer control system, and the LUSM is driven by a unipolar switching full bridge voltage source inverter using LC resonant technique. Finally, the effectiveness of the RFNN-controlled LUSM drive system is demonstrated by some experimental results. Accurate tracking response and superior dynamic performance can be obtained because of the powerful on-line learning capability of the RFNN controller. Furthermore, the RFNN control system is robust with regard to parameter variations and external disturbances. PMID:11477782

  6. 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

  7. 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 320spC. 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 800-900spC for 2-5 hrs and then sintered at 1050-1200spC for 1-4 hrs. Conventional poling was performed at 50spC 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.

  8. 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.

  9. Structural characteristics of Mg-doped (1-x)(K0.5Na0.5)NbO3-xLiSbO3 lead-free ceramics as revealed by Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Zhu, W. L.; Zhu, J. L.; Meng, Y.; Wang, M. S.; Zhu, B.; Zhu, X. H.; Zhu, J. G.; Xiao, D. Q.; Pezzotti, G.

    2011-12-01

    This paper presents a Raman spectroscopic study of compositional-change-induced structure variation and of the related mechanism of Mg doping in LiSbO3 (LS)-modified (K0.5Na0.5)NbO3 (KNN) ceramics. With increasing LS content from 0 to 0.06, a discontinuous shift towards higher wavenumbers was found for the band position of the A1g(v1) stretching mode of KNN, accompanied by a clearly nonlinear broadening of this band and a decrease in its intensity. Such morphological changes in the Raman spectrum result from two factors: (i) changes in polarizability/binding strength of the O-Nb-O vibration upon incorporation of Li ions in the KNN perovskitic structure and (ii) a polymorphic phase transition (PPT) from orthorhombic to tetragonal (O ? T) phase at x > 0.04. Upon increasing the amount, w, of Mg dopant incorporated into the (1-x)KNN-xLS ceramic structure, the intensity of the Raman bands are enhanced, while the peak position and the full width at half maximum of the A1g(v1) mode was found to experience a clear dependence on both w and x. Raman characterization revealed that the mechanism of Mg doping is strongly correlated with the concentration of Li in the perovskite structure: Mg2+ ions will preferentially replace Li+ ions for low Mg doping while replace K/Na ions for higher doping of Mg. The PPT O ? T was also found to be altered by the introduction of Mg and the critical value of LS concentration, xO-T, for incipient O ? T transition in the KNN-xLS-wMT system was strongly dependent on Mg content, with xO ? T being roughly equal to 0.04 + 2w, for the case of dilute Mg alloying.

  10. 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.

  11. Rhombohedral-tetragonal phase boundary and electrical properties of new K0.48Na0.52Nb0.98Sb0.02O3-Bi0.5Na0.5ZrO3 lead-free piezoceramics

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

    (1 - x)K0.48Na0.52Nb0.98Sb0.02O3-xBi0.5Na0.5ZrO3 lead-free piezoceramics were prepared by using the conventional solid-state method. In this material system, (Bi0.5Na0.5)2+ and Zr4+ can decrease the orthorhombic-tetragonal phase temperature and increase the rhombohedral-orthorhombic phase temperature. The rhombohedral-tetragonal phase coexistence is identified in the ceramics with the compositional range of 0.03 < x < 0.05. The ceramic with x = 0.04 has an enhanced piezoelectric behaviour of d33 257 pC N-1 and kp 41%, which is three times higher than that of a pure KNN ceramic. In addition, the enhanced stability of piezoelectric and ferroelectric properties is also observed in such a ceramic. These results show that such a new lead-free material system is a promising candidate for piezoelectric devices.

  12. Effect of Processing on Synthesis and Dielectric Properties of Lead free (Bi0.98R0.02)0.5Na0.5TiO3 Ceramics

    NASA Astrophysics Data System (ADS)

    Pal, Vijayeta; Dwivedi, R. K.

    2015-02-01

    In the present work, an effort has been made to synthesize (Bi1-xRx)0.5Na0.5TiO3 (BRNT) system with compositions x = 0 & 0.02, where R = La, Nd and Gd by Semi-Wet Technique. Processing of the composition with x = 0 has been optimized by two precursor solution one by citric acid and other by ethylene glycol. The XRD patterns of these samples, prepared by ethylene glycol precursor solution, have shown pure phase of perovskite structure with a rhombohedral symmetry. The studies on structure, phase transitions and dielectric properties for all the samples have been carried out over the temperature range from RT to 450 C at 100 kHz frequency. It has been observed that two phase transitions (i) ferroelectric to anti-ferroelectric and (ii) anti ferroelectric to paraelectric occur in all the samples. All samples exhibit a modified Curie-Weiss law above Tc. A linear fitting of the modified Curie- Weiss law to the experimental data shows diffuse type transition. The dielectric properties of BNT ceramics have been found to be improved with the substitution of rare earth elements.

  13. 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.

  14. 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.

  15. 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.

  16. Effect of uniaxial stress on the large-signal electromechanical properties of electrostrictive and piezoelectric lead magnesium niobate lead titanate ceramics

    NASA Astrophysics Data System (ADS)

    Viehland, D.; Li, Jie-Fang; McLaughlin, E.; Powers, J.; Janus, R.; Robinson, H.

    2004-02-01

    The electromechanical performance characteristics of electrostrictive 0.9 Pb(Mg1/3Nb2/3)O3-0.1 PbTiO3 and piezoelectric 0.7 Pb(Mg1/3Nb2/3)O3-0.3 PbTiO3 ceramics have been investigated under uniaxial stress (?). The results demonstrate that the large-signal electromechanical properties of electrostrictive ceramics are decreased with increasing ?, whereas those of the piezoelectric are increased but accompanied by significantly increased hysteretic losses.

  17. 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

  18. 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.

  19. 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.

  20. 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.

  1. 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

  2. Effects of K4CuNb8O23 on phase structure and electrical properties of K0.5Na0.5NbO3-LiSbO3 lead-free piezoceramics

    NASA Astrophysics Data System (ADS)

    Liu, Yong; Chu, Ruiqing; Xu, Zhijun; Lv, Huiqin; Wu, Liming; Yang, Yizheng; Li, Guorong

    2012-07-01

    Dense K4CuNb8O23 (KCN) modified 0.948K0.5Na0.5NbO3-0.052LiSbO3 (KNNLS) ceramics were prepared by conventional solid state reaction method. The effect of addition of K4CuNb8O23 liquid phase sintering aid on the phase structure and electrical properties of ceramics was studied. Results showed that K4CuNb8O23 induced a perovskite structure transition from coexistence of orthorhombic and tetragonal phases to orthorhombic symmetry. The addition of K4CuNb8O23 promoted the sintering of KNNLS ceramics. In particular, the K4CuNb8O23 addition to the KNNLS greatly improved the mechanical quality factor Qm value. The ceramics with x=0.8 sintered at 1090 C possess the optimum properties (Qm=192, d33=135 pC/N, tan ?=0.024 and kp=0.357). These results indicate that the ceramic is a promising candidate for lead-free high-power piezoelectric devices, such as piezoelectric actuators, transformers and filter materials.

  3. 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, ? r = 1823, tan ? = 0.0054, P r = 19.26 ?C/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.

  4. 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.

  5. 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)O3Pb(Mg1?3Nb2?3)O3PbTiO3 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)O3PbTiO3 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

  6. 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.

  7. 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

  8. 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

  9. 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.

  10. 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 ?C/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.

  11. Piezoelectric and Mechanical Properties of BaBi4Ti4O15/Ba4Ti13O30 Ceramics

    NASA Astrophysics Data System (ADS)

    Nakai, Yasuhiro; Fukuoka, Shuichi

    1999-09-01

    This article presents the piezoelectric and mechanical properties of bismuth layer-structured ferroelectrics (BLSF)-based BaBi4Ti4O15 ceramics incorporating Ba4Ti13O30. The ceramic compositions, (1-x)BaBi4Ti4O15 xBa4Ti13O30 with x=0 100 vol%, are obtained through solid-state reaction processes. The dielectric constant, ?33T/?0, decreases exponentially from 220 to 97 with increasing x from 0 to 66 vol%. The electromechanical coupling factor, k33, decreases from 15 to 7% with increasing x from 0 to 66 vol%. The fracture toughness, KIC, and flexural strength, ?, of the compositions with x?39 vol% are almost identical to those of Ba4Ti13O30. At x?39 vol%, KIC and ? are nearly 15 and 30% larger than those of BaBi4Ti4O15, respectively. Ba4Ti13O30 particles dispersed uniformly in the ceramics are capable of carrying an applied load effectively and lead to further improvements of the mechanical properties.

  12. 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.

  13. Accurate Characterization And Modeling of Piezoelectric And Electrostrictive Ceramics And Single Crystals

    SciTech Connect

    Mukherjee, Binu

    2008-07-29

    The continuing need for large actuation and a continually increasing variety of applications has seen the use of piezoelectric materials under a growing range of conditions. These include large applied AC fields, DC bias fields, applied stresses as well as a wider range of frequencies and temperatures. Under these conditions the behaviour of the materials becomes non-linear and is not described well by the small signal parameters supplied by material manufacturers. It is therefore necessary to know and understand the behaviour of piezoelectric materials under these conditions. This presentation reviews the work that has been carried out at the Laboratory for Ferroelectric Materials in the Royal Military College of Canada where we have been studying the non-linear properties of piezoelectric and electrostrictive materials by observing their strain, dielectric and elastic behaviour under the various conditions mentioned above.

  14. 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.

  15. 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.

  16. 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.}

  17. 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).

  18. 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

  19. Structure, dielectric and piezoelectric properties of K0.5Na0.5NbO3-Bi0.5(Na0.7K0.2Li0.1)0.5TiO3 ceramics

    NASA Astrophysics Data System (ADS)

    Lin, Dunmin; Huang, Damin; Zheng, Qiaoji

    2013-07-01

    (1-x)K0.5Na0.5NbO3-xBi0.5(Na0.7K0.2Li0.1)0.5TiO3+1 mol% MnO2 lead-free ceramics were prepared by an ordinary sintering method and their structure, dielectric and piezoelectric properties were investigated. A K0.5Na0.5NbO3-based solid solution with perovskite structure is formed after the addition of Bi0.5(Na0.7K0.2Li0.1)0.5TiO3 to K0.5Na0.5NbO3. A small amount of Bi0.5(Na0.7K0.2Li0.1)0.5TiO3 retards the grain growth, induces a diffuse phase transition at TC, decreases Curie temperature and weakens the ferroelectricity of the ceramics. The ferroelectric orthorhombic-ferroelectric tetragonal phase at TO-T is shifted to low temperature after the addition of (Na0.7K0.2Li0.1)0.5TiO3, leading to the formation of the coexistence of orthorhombic and tetragonal phases near room temperature at 0.015piezoelectric properties are obtained in the ceramics situated near the coexistence zone of two phases. The ceramic with x=0.030 possesses the relatively high TC of 372 C and large d33 of 183 pC/N.

  20. 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.

  1. 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.

  2. Application of gel-casting to the fabrication of 1-3 piezoelectric ceramic-polymer composites for high-frequency ultrasound devices

    NASA Astrophysics Data System (ADS)

    Garca-Gancedo, L.; Olhero, S. M.; Alves, F. J.; Ferreira, J. M. F.; Demor, C. E. M.; Cochran, S.; Button, T. W.

    2012-12-01

    A modified gel-casting technique was used to fabricate a 1-3 piezoelectric ceramic/polymer composite substrate formed by irregular-shaped pillar arrays of small dimensions and kerfs. This technique involves the polymerization of aqueous piezoelectric (PZT) suspensions with added water-soluble epoxy resin and polyamine-based hardener that lead to high strength, high density and resilient ceramic bodies. Soft micromoulding was used to shape the ceramic segments, and micropillars with lateral features down to 4 m and height-to-width aspect ratios of 10 were achieved. The composite exhibited a clear thickness resonance mode at approximately 70 MHz and a keff 0.51, demonstrating that the ceramic micropillars possess good electrical properties. Furthermore, gel-casting allows the fabrication of ceramic structures with non-conventional shapes; hence, device design is not limited by the standard fabrication methods. This is of particular benefit for high-frequency transducers where the critical design dimensions are reduced.

  3. 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.

  4. 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 ?C 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.

  5. 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.

  6. Effects of porosity on dielectric and piezoelectric properties of porous lead zirconate titanate ceramics

    NASA Astrophysics Data System (ADS)

    Yang, An-Kun; Wang, Chang-An; Guo, Rui; Huang, Yong

    2011-04-01

    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 (959410-15 m2/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.

  7. 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.

  8. Efficient Algorithm Using a Broadband Approach to Determine the Complex Constants of Piezoelectric Ceramics

    NASA Astrophysics Data System (ADS)

    Buiochi, F.; Kiyono, C. Y.; Perz, N.; Adamowski, J. C.; Silva, E. C. N.

    A new systematic and efficient algorithm to obtain the ten complex constants of piezoelectric materials belonging to the 6 mm symmetry class was developed. A finite element method routine was implemented in Matlab using eight-node axisymmetric elements. The algorithm raises the electrical conductance and resistance curves and calculates the quadratic difference between the experimental and numerical curves. Finally, to minimize the difference, an optimization algorithm based on the "Method of Moving Asymptotes" (MMA) is used. The algorithm is able to adjust the curves over a wide frequency range obtaining the real and imaginary parts of the material properties simultaneously.

  9. 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

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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

  7. 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.

  8. 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.

  9. Dielectric, piezoelectric, and ferroelectric properties of grain-orientated Bi{sub 3.25}La{sub 0.75}Ti{sub 3}O{sub 12} ceramics

    SciTech Connect

    Liu Jing; Shen Zhijian; Yan Haixue; Reece, Michael J.; Kan Yanmei; Wang Peiling

    2007-11-15

    By dynamic forging during Spark Plasma Sintering (SPS), grain-orientated ferroelectric Bi{sub 3.25}La{sub 0.75}Ti{sub 3}O{sub 12} (BLT) ceramics were prepared. Their ferroelectric, piezoelectric, and dielectric properties are anisotropic. The textured ceramics parallel and perpendicular to the shear flow directions have similar thermal depoling behaviors. The d{sub 33} piezoelectric coefficient of BLT ceramics gradually reduces up to 350 deg. C; it then drops rapidly. The broadness of the dielectric constant and loss peaks and the existence of d{sub 33} above the permittivity peak, T{sub m}, show that the BLT ceramic has relaxor-like behavior.

  10. Development of lead-free solders for hybrid microcircuits

    SciTech Connect

    Hosking, F.M.; Vianco, P.T.; Frear, D.R.; Robinson, D.G.

    1996-01-01

    Extensive work has been conducted by industry to develop lead-free solders for electronics applications. The driving force behind this effort is pressure to ban or tax the use of lead-bearing solders. There has been further interest to reduce the use of hazardous chemical cleaners. Lead-free soldering and low-residue, ``no clean`` assembly processing are being considered as solutions to these environmental issues. Most of the work has been directed toward commercial and military printed wiring board (PWB) technology, although similar problems confront the hybrid microcircuit (HMC) industry, where the development of lead-free HMC solders is generally lagging. Sandia National Laboratories is responsible for designing a variety of critical, high reliability hybrid components for radars. Sandia has consequently initiated a project, as part of its Environmentally Conscious Manufacturing program, to develop low-residue, lead-free soldering for HMCs. This paper discusses the progress of that work.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. Wettability analysis of tin-based, lead free solders

    SciTech Connect

    Vianco, P T; Hosking, F M; Rejent, J A

    1992-01-01

    The overall program is comprised of two efforts. The first effort studies the wettability of tin-based, lead free solders on two commonly used substrate materials: copper and gold-nickel plated Kovar{trademark}. The evaluation is being conducted by the meniscometer/wetting balance technique which uses the contact angle as the primary metric to quantify wettability. Information about the rate of wetting is also obtainable with this test. The second part of the program is comprised of an assessment of the solderability of actual circuit board assemblies (surface mount and through-hole). This report will describe data from the wettability analysis of lead free solders on copper.

  18. Piezoresponse and ferroelectric properties of lead-free [Bi0.5(Na0.7K0.2Li0.1)0.5]TiO3 thin films by pulsed laser deposition

    NASA Astrophysics Data System (ADS)

    Wang, D. Y.; Lin, D. M.; Wong, K. S.; Kwok, K. W.; Dai, J. Y.; Chan, H. L. W.

    2008-06-01

    Polycrystalline lead-free piezoelectric [Bi0.5(Na0.7K0.2Li0.1)0.5]TiO3 (BNKLT) thin films were grown on Pt /Ti/SiO2/Si substrates using pulsed laser deposition (PLD). In this letter, we report the ferroelectric properties and piezoresponse of the PLD-produced BNKLT thin films. X-ray diffraction characterization revealed a good crystallinity and a pure perovskite structure in the films. The films exhibited a well-defined polarization hysteresis loop with a remnant polarization Pr of 13.9?C/cm2 and a coercive field Ec of 10.2MV/m. The domain structure and its thermal-driven evolution from the ferroelectric to nonferroelectric phase were observed by piezoresponse force microscopy. The results were consistent with the phase transition profile of BNKLT bulk ceramics. Typical butterfly-shaped piezoresponse loop was obtained and the effective piezoelectric coefficient d33,f of the BNKLT thin films was about 64pm/V.

  19. Evaluation of lead-free solder joints in electronic assemblies

    SciTech Connect

    Artaki, I.; Jackson, A.M.; Vianco, P.T.

    1994-08-01

    The feasibility of printed circuit board assembly with lead-free solder alloys was investigated. Studies were conducted with two baseline eutectic binary alloys, SnBi and SnAg, and three new lead-free solder formulations: (1) 91.8Sn-4.8Bi-3.4Ag (wt%) developed at Sandia Laboratories, (2) 77.2Sn-20In-2.8Ag developed at Indium Corp. of America, and (3) 96.2Sn-2.5Ag-0.8Cu-0.5Sb provided by AIM Inc. The basic physical properties (melting temperature, wetting, mechanical strength) pertinent to each of the newly developed alloys are described. The feasibility of 0.4 mm pitch assembly was established with each of the lead-free solder alloys investigated, although the processing windows were generally found to be narrower. All solder joints exhibited good fillets, in accordance with the workmanship standards. Wetting of the lead-free solders was significantly improved on immersion tin vs imidazole finished circuit boards. The laminates did not suffer thermal degradation effects, such as warpage, delamination, or severe discoloration (reflow was performed under an inert atmosphere). It is thus concluded that the manufacturability performance of the new solder formulations is adequate for surface mount applications. 23 refs., 7 figs., 4 tabs.

  20. Crystal structure analysis of lead free Ba{sub 1-x}La{sub x}[Ti{sub 0.5}(Fe{sub 0.5}Nb{sub 0.5}){sub 0.5}]{sub 1-x/4}O{sub 3} Ceramics

    SciTech Connect

    Patel, Piyush Kumar; Rani, Jyoti; Yadav, K. L.

    2012-06-05

    Single phase Ba{sub 1-x}La{sub x}[Ti{sub 0.5}(Fe{sub 0.5}Nb{sub 0.5}){sub 0.5}]{sub 1-x/4}O{sub 3} [referred as BT-LFN]; x=0, 0.02, 0.04 and 0.06 ceramics have been synthesized by solid - state reaction process and were characterized by X-ray diffraction technique. The microstructure of the ceramics was examined by field emission-scanning electron microscopy (FE-SEM).

  1. 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.

  2. Dielectric, Piezoelectric Properties and Field-Induced Large Strain of Bi(Zn0.5Ti0.5)O3-Modified Morphotropic Phase Boundary Bi0.5(Na0.82K0.18)0.5TiO3 Piezoelectric Ceramics

    NASA Astrophysics Data System (ADS)

    Ullah, Aman; Ahn, Chang Won; Kim, Ill Won

    2012-09-01

    In this study, the effects of Bi(Zn0.5Ti0.5)O3 (BZT) on the structure, dielectric, ferroelectric, and piezoelectric properties of morphotropic phase boundary Bi0.5(Na0.82K0.18)0.5TiO3 (BNKT18) piezoelectric ceramics were investigated. In the composition range studied, X-ray diffraction results revealed the coexistence of rhombohedral and tetragonal phases. It was found that BZT content decreased the depolarization temperature (Td) of BNKT18-BZT ceramics, and the degree of diffuseness of the phase transition became more obvious with increasing BZT content. The addition of a small amount of BZT improved the piezoelectric properties, with the maximum piezoelectric constant (d33=166 pC/N) and electromechanical coupling factor (kp=31.7%) obtained at x=0.03. However, at a high concentration of BZT, the remanent polarization and piezoelectric constant d33 were drastically decreased, and a pronounced enhancement in electric field-induced strain was observed, with a peak of 0.27% at x=0.07, which corresponds to a normalized strain, Smax/Emax, of 385 pm/V.

  3. 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).

  4. 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.

  5. 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 m 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.

  6. Rare earths in lead-free oxyfluoride germanate glasses.

    PubMed

    Pisarski, Wojciech A; Pisarska, Joanna; Dorosz, Dominik; Dorosz, Jan

    2015-01-01

    Spectroscopic properties of rare earths in lead-free oxyfluoride germanate glasses were studied. The absorption and luminescence spectra of Eu(3+), Pr(3+) and Er(3+) ions were examined as a function of BaF? concentration and several spectroscopic parameters for rare earths were determined. The ratio of integrated luminescence intensity of the (5)D??(7)F? transition to that of the (5)D??(7)F? transition of Eu(3+) decrease significantly with increasing BaF? content. The absorption (Er(3+)) and emission (Pr(3+)) 'hypersensitive transitions' of rare earths are shifted in direction to shorter wavelengths with increasing BaF? content in glass composition. Emission spectra and their decays corresponding to the main (4)I??/??(4)I??/? laser transition of Er(3+) were also analyzed. Quite long-lived NIR luminescence of Er(3+) is observed for lead-free glass samples with low BaF? concentration. PMID:25088539

  7. 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.

  8. Underfill process development for lead free flip chip assembly

    NASA Astrophysics Data System (ADS)

    Chaware, Raghunandan

    Underfills are used to enhance the long-term reliability of the flip-chip solder joints. More specifically, the function of the underfill is to couple the chip to the substrate, wherein the shear stresses experienced by the solder joints are converted to bending stresses. The underfill flows under the die due to the influence of strong capillary forces. The flow of the underfill under the chip depends on various factors such as the viscosity of the underfill, contact angle, surface tension, temperature, underfill gap, substrate design, bump pattern, bump density, and size of the chip. The flow of underfill is also influenced by the cleanliness of the substrate, the cleanliness of the underside of the chip, and the flux residues. The interaction between the underfill and the substrate affects not only gap filling, but also the filleting of the underfill. Similarly, the underfill-flux interaction directly affects the quality of underfilling and the reliability of the flip chip assembly. In the case of lead free flip chip assembly, the major concerns vis-a-vis process development for a large chip with a small bump pitch (less than 190 mum) include lower throughput, voiding under the chip, and critical reliability performance. The principal objective of this research endeavor was to investigate the fundamental issues that relate to the process and reliability aspects of underfilling of lead free flip chip assemblies. In order to develop a robust underfilling process, the effect of different process parameters and their interaction with the material properties were studied. In order to improve the compatibility between the underfill and the flux, a new epoxy flux that was compatible with the lead free assembly process was developed. The performance of the epoxy was also compared with the performance of various rosin based fluxes. This study also helped in identifying the critical parameters that can affect the assembly yields. This research endeavor successfully contributed towards defining dispensing process windows for the underfills that were compatible with the lead free process. In conclusion, the proposed research contributed towards the development of the fundamental understanding of the capillary underfilling process for lead free flip chip assemblies.

  9. 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.

  10. Growth and characterization of lead-free ferroelectric (K,Na,Li)(Nb,Ta,Sb)O3 single crystal

    NASA Astrophysics Data System (ADS)

    Wang, Junjun; Zheng, Limei; Yang, Bin; Wang, Rui; Huo, Xiaoqing; Sang, Shijing; Wu, Jie; Chang, Yunfei; Ning, Huanpo; Lv, Tianquan; Cao, Wenwu

    2015-01-01

    In this work, a large size lead-free piezoelectric single crystal, (K,Na,Li)(Nb,Ta,Sb)O3 (KNLNTS) with the dimensions of 8.58.513.5 mm3 was successfully grown by the top-seeded solution growth method. This KNLNTS single crystal with high compositional homogeneity is in the tetragonal phase at room temperature. The Curie temperature TC of the tetragonal-cubic phase transition temperature is 210 C. The piezoelectric coefficients and electromechanical coupling factors of the [001]C oriented KNLNTS single crystal are d33=172.55 pC/N, d31=-71.90 pC/N, k31=0.327, k33=0.523, and kt=0.541. In addition, the crystal shows good thermal stability so that it can be used for making high temperature electromechanical devices.

  11. 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.

  12. Aging of piezoelectric properties in Pb(MgNb)O3-Pb(ZrTi)O3 multilayer ceramic actuators

    NASA Astrophysics Data System (ADS)

    Koh, Jung-Hyuk; Jeong, Soon-Jong; Ha, Mun-Su; Song, Jae-Sung

    2004-07-01

    Aging characteristics of 0.2(PbMg1/3Nb2/3O3)-0.8(PbZr0.475Ti0.525O3) multilayer ceramic actuators have been investigated by applying rectified ac bias. Multilayer ceramic actuators 555 mm3 in size were fabricated by tape-casting methods. X-ray diffraction analyses were performed to compare crystalline structures and lattice parameters. Effective electromechanical coupling coefficient keff and pseudopiezoelectric constant d33 were calculated and discussed. Different rectified ac electric biases were applied to the actuators to investigate aging behavior in the multilayer ceramic actuators. The aging dependencies of cycles and electric fields were simulated and fitted to the linear logarithmic stretched exponential law.

  13. High temperature piezoelectric drill

    NASA Astrophysics Data System (ADS)

    Bao, Xiaoqi; Scott, James; Boudreau, Kate; Bar-Cohen, Yoseph; Sherrit, Stewart; Badescu, Mircea; Shrout, Tom; Zhang, Shujun

    2009-03-01

    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 (460C), 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 1000C and the piezoelectric ceramics Bismuth Titanate higher than 600C. A study of the feasibility of producing piezoelectric drills that can operate in the temperature range up to 500C 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 500C. The detailed results of our study and a discussion of the future work on performance improvements are presented in this paper.

  14. 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.

  15. 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.

  16. Origin of the large piezoelectric activity in (1 -x ) Ba (Z r0.2T i0.8)O3-x (B a0.7C a0.3) Ti O3 ceramics

    NASA Astrophysics Data System (ADS)

    Acosta, Matias; Khakpash, Nasser; Someya, Takumi; Novak, Nikola; Jo, Wook; Nagata, Hajime; Rossetti, George A.; Rdel, Jrgen

    2015-03-01

    The diffusionless pseudobinary phase diagram, monodomain properties, and free energy of (1 -x ) Ba (Z r0.2T i0.8)O3-x (B a0.7C a0.3) Ti O3 are computed for comparison with experimental results. Specifically, the variation of the spontaneous polarization, anisotropy energy, and free energy with respect to temperature, composition, and polarization direction are discussed relative to the results of resonant piezoelectric measurements performed over a wide compositional range as a function of temperature. The phase angle, relative permittivity, piezoelectric and coupling coefficients, and elastic compliances were used to investigate relations between the computed and measured pseudobinary phase diagrams and the measured piezoelectric and elastic properties. It was found that d33 values along the orthorhombic to tetragonal phase boundary are 30 % higher than those both along the rhombohedral to orthorhombic phase boundary and in the region where phases converge. It is shown that the reduction in anisotropy energy in these regions of the phase diagram is by itself insufficient to explain the measured properties. The highest small signal piezoelectric activity is found along the orthorhombic to tetragonal phase boundary due to a combination of reduced anisotropy energy, high remanent/spontaneous polarization, and increased elastic softening. The combined computed and experimental results are used to demonstrate that the interdependent behavior of these properties should be considered in the design of engineered piezoelectric ceramics.

  17. Piezoelectric properties of nonstoichiometric Sr{sub 1-x}Bi{sub 2+2x/3}Ta{sub 2}O{sub 9} ceramics

    SciTech Connect

    Jain, Rajni; Chauhan, Arun Kumar Singh; Gupta, Vinay; Sreenivas, K.

    2005-06-15

    The effect of poling on the structural, dielectric, and piezoelectric properties has been investigated for sol-gel-derived strontium bismuth tantalate (SBT) [Sr{sub 1-x}Bi{sub 2+2x/3}Ta{sub 2}O{sub 9}] 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 (BiTaO{sub 4}) is detected with x=0.45. Poling treatment reduces the dielectric dispersion and dielectric loss in the frequency range (0.1-100 kHz). The resonance and antiresonance frequencies increase with increase in x (x=0-0.30), and the corresponding minimum impedance decreases. The measured coupling coefficients (k{sub p}) are small (0.0967-0.1) for x=0-0.30, and the electromechanical quality factor (Q{sub m}=915) is a maximum for the Sr{sub 0.7}Bi{sub 2.2}Ta{sub 2}O{sub 9} composition (x=0.30). The estimated piezoelectric charge coefficient (d{sub 31}) and piezoelectric voltage coefficient (g{sub 31}) are 5.2 pC/N and 5.8x10{sup -3} V m/N, respectively. The positive values of d{sub 31} and g{sub 31} and the low dielectric permittivity of SBT yield a high value for the hydrostatic coefficients, despite the low charge coefficient of d{sub 33}=24 pC/N. The maximum values of charge coefficient (d{sub h}=34 pC/N) and voltage coefficient (g{sub h}=39x10{sup -3} V m/N) are obtained for Sr{sub 0.7}Bi{sub 2.2}Ta{sub 2}O{sub 9} composition, and the estimated hydrostatic figure of merit (d{sub h}g{sub h}x10{sup -15}=1215 m{sup 2}/N) is high.

  18. 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 C/cm2, coercive field Ec = 64 kV/cm, piezoelectric constant d33 = 41 pC/N, dielectric constant \\varepsilon 33\\text{T}/\\varepsilon 0 = 258, loss tan ? = 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, ?r = 217, tan ? = 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 ? = 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.

  19. Investigation of multi-component lead-free solders

    NASA Astrophysics Data System (ADS)

    Loomans, M. E.; Vaynman, S.; Ghosh, G.; Fine, M. E.

    1994-08-01

    Binary phase diagrams of interest for lead-free solder development have been entered into the THERMO-CALC data base. These may be used directly to calculate multi-component phase relations vs temperature provided there are no ternary or higher order interactions. Such occur in the Sn-Ag-Zn system and are being evaluated. Contact angles of a number of solder-flux combinations on copper were directly measured in spreading tests. With a rosin-isopropyl alcohol flux, the contact angles of binary eutectic solders were in degrees: Sn-Bi at 166C, 40; Sn-Zn at 225C, 60; Sn-Ag at 250C, 45. These angles were little affected by a number of 1% ternary additions to the solder. The contact angles were 20 degrees or less when SnCl2 was used as a flux. The SnCl2 reacts with Cu to form Cu3Sn. The most likely successful approach to obtain satisfactory wetting with lead-free solders appears to be development of a satisfactory flux.

  20. 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.

  1. 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

  2. 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.

  3. 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 ?W) 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 ?W) 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

  4. 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

  5. Hole conduction and electro-mechanical properties of Na0.5Bi2.5Ta2O9-based piezoelectric ceramics with the Li+/Ce3+/Sc3+ modification

    NASA Astrophysics Data System (ADS)

    Long, Changbai; Fan, Huiqing; Wu, Yun; Li, Yinghong

    2014-08-01

    Na0.5Bi2.5Ta2O9-based piezoelectric ceramics, Na0.5-xBi0.5-xLixCexBi2Ta2-xScxO9-x (NBTO-x, x = 0-0.05), were synthesized by using a solid-state reaction process, and their electro-mechanical properties and electrical conduction behaviors were investigated in detail. The Li+/Ce3+/Sc3+ modification improved the electro-mechanical properties of the ceramics effectively, whereas further N2 or O2 annealing led to no obvious increase in piezoelectric coefficient (d33). The composition x = 0.03 ceramic with high temperature stability had a Curie point (Tc) of 784 C and a d33 of 25.8 pC/N, and its electromechanical coupling factors, kp and kt, were 11.8% and 20.7%, respectively. Variable-atmosphere (air, O2 and N2) impedance data suggested that the NBTO-x ceramics were mainly p-type materials contributing from the bulk response, and the conducting species were holes (h). Therefore, lower bulk resistivity (?) and lower activation energy (Ea) were associated with the treatment with higher PO2 (oxygen partial pressure). In addition, the O2 atmosphere had stronger impact on the conductivity of the pure NBTO than those of the acceptor NBTO-x, and the grain and grain boundary contributed to its resistivity together.

  6. 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.

  7. 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.}

  8. A high temperature piezoelectric ceramic: (1-x)(Bi0.9La0.1)FeO(3-x)PbTiO3 crystalline solutions.

    PubMed

    Chen, Jianguo; Qi, Yufa; Shi, Guiyang; Yu, Shengwen; Cheng, Jinrong

    2009-09-01

    (1-x)(Bi(0.9)La(0.1))FeO(3-x)PbTiO(3) (BLF-PT) crystalline solutions for x = 0.35, 0.37, 0.4, 0.43 and 0.45 have been prepared by the solid-state reaction method. The X-ray diffraction analysis shows that BLF-PT has a single perovskite phase with mixed tetragonal and rhombohedral phases between x = 0.4 and 0.43. The Curie temperature of BLF-PT for x = 0.4 attains 460 degrees C, which is about 80 degrees C higher than that of hard Pb(Zr,Ti)O(3) ceramics. The remnant polarization and piezoelectric constant of BLF-PT for x = 0.4 reach 38 microC/cm(2) and 112 pC/N, respectively. The planar coupling factor k(p) of BLF-PT for x = 0.4 remains stable at temperature increases of up to 360 degrees C. The impedance spectroscopy study reveals that the high temperature conduction of BLF-PT may be attributed to the motion of oxygen vacancies within the material. Our results indicate that BLF-PT is a promising candidate for high temperature applications. PMID:19811982

  9. 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

  10. Strong electrocaloric effect in lead-free 0.65Ba(Zr0.2Ti0.8)O3-0.35(Ba0.7Ca0.3)TiO3 ceramics obtained by direct measurements

    NASA Astrophysics Data System (ADS)

    Sanlialp, Mehmet; Shvartsman, Vladimir V.; Acosta, Matias; Dkhil, Brahim; Lupascu, Doru C.

    2015-02-01

    Solid solutions of (1 - x)Ba(Zr0.2Ti0.8)O3-x(Ba0.7Ca0.3)TiO3 promise to exhibit a large electrocaloric effect (ECE), because their Curie temperature and a multiphase coexistence region lie near room temperature. We report on direct measurements of the electrocaloric effect in bulk ceramics 0.65Ba(Zr0.2Ti0.8)O3-0.35(Ba0.7Ca0.3)TiO3 using a modified differential scanning calorimeter. The adiabatic temperature change reaches a value of ?TEC = 0.33 K at 65 C under an electric field of 20 kV/cm. It remains sizeable in a broad temperature interval above this temperature. Direct measurements of the ECE proved that the temperature change exceeds the indirect estimates derived from Maxwell relations by about 50%. The discrepancy is attributed to the relaxor character of this material.

  11. 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.

  12. Novel 0.50(Bi1-xLax)FeO3-0.35PbTiO3-0.15Bi(Zn1/2Ti1/2)O3 Piezoelectric Ceramics for High Temperature High Frequency Filters

    NASA Astrophysics Data System (ADS)

    Hou, Xianbo; Yu, Jian

    2013-06-01

    Perovskite-structured 0.50(Bi1-xLax)FeO3-0.35PbTiO3-0.15Bi(Zn1/2Ti1/2)O3 ceramics with x = 0.0-0.2 were fabricated with traditional solid state reaction method. Their crystallographic structure, dielectric and piezoelectric properties were investigated with various La contents. It was observed that a structural phase transition undergoes from tetragonal to coexistent tetragonal and rhombohedral phase when x?0.05 and that the tetragonality of c/a ratio and Curie temperature decrease but piezoelectric properties increase with increasing La content. The enhanced piezoelectric performance with La substitution was attributed to the lattice structural changes from the tetragonal phase into the coexistent tetragonal and rhombohedral phase accompanying with tetragonality decreasing. For the Pb0.35Bi0.625La0.025(Ti0.425Zn0.075Fe0.5)O3 ceramics closely at the structural phase boundary poled at 140 C with 5 kV/mm DC electric field, a good piezoelectric property of d33 = 43 pC/N, ?33T/?0 = 367 and TC = 497 C was obtained, which is comparable with the commercial Matsushita lead titanate (MLT) piezoelectric ceramics with d33 = 51 pC/N, ?33T/?0 = 170 and TC = 495 C and much promising for application in the fields of high temperature high frequency piezoelectric ceramic filters.

  13. Aging in the relaxor and ferroelectric state of Fe-doped (1-x)(Bi{sub 1/2}Na{sub 1/2})TiO?-xBaTiO? piezoelectric ceramics

    SciTech Connect

    Sapper, Eva; Dittmer, Robert; Rdel, Jrgen; Damjanovic, Dragan; Erdem, Emre; Keeble, David J.; Jo, Wook; Granzow, Torsten

    2014-09-14

    Aging of piezoelectric properties was investigated in lead-free (1x)(Bi{sub 1/2}Na{sub 1/2})TiO?-xBaTiO? 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.

  14. 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.

  15. 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.

  16. Influence of Mixing Condition and Nonstoichiometry on Piezoelectric Properties of (K, Na, Pb)NbO3 Ceramics

    NASA Astrophysics Data System (ADS)

    Tashiro, Shinjiro; Nagata, Kunihiro

    2004-09-01

    To obtain a uniform mixture of raw material powders including K2CO3 and Na2CO3, the raw material powders were ball-milled in a mixture of water and methanol (first-stage mixing). After the first-stage mixing, the dried powders were mixed again by ball-milling in acetone (second-stage mixing). Samples were fabricated using the two mixing methods, one-stage mixing and two-stage mixing. In the material composition formula, (Pb0.03K0.47Nax)Nb0.994O3, the composition was changed from A-site rich to B-site rich by reducing Na content in steps of 0.01 from x=0.50. The change in the piezoelectric properties of these samples was measured. As the B-site ion concentration exceeds A-site ion concentration, the crystal structure changed from pseudocubic to orthorhombic. The electromechanical coupling factor and remanent polarization of the samples increased in accordance with the change in crystal structure. The defect structure having A-site vacancies due to a B-site-rich composition is effective in inducing ferroelectricity.

  17. Dielectric properties and electrical conduction of La2O3-doped (Bi0.5Na0.5)0.94Ba0.06TiO3 ceramics

    NASA Astrophysics Data System (ADS)

    Li, Qiang; Wang, Hairong; Fan, Huiqing; Xu, Mengmeng; Peng, Biaolin; Long, Changbai; Liu, Xiao

    2014-02-01

    La2O3 (2 wt%)-doped (Bi0.5Na0.5)0.94Ba0.06TiO3 (abbreviated as BNBT6) lead-free piezoelectric ceramics were synthesized by conventional solid-state reaction. X-ray diffraction (XRD) patterns indicated that La2O3 has diffused into the lattice of BNBT6 ceramics and formed a solid solution with a pure perovskite structure. Addition of La2O3 decreased the piezoelectric properties and electrical conductivity. It was used to study the electrical conductivity of the La2O3-doped BNBT6 lead-free piezoelectric ceramics combined with electrical modulus and impedance plots at the temperature range over 788-873 K. The values of activation energy derived from the electrical impedance and modulus were found to be 0.51 and 0.50 eV, respectively. The discrepancy between activation energy of relaxation frequency and the activation energy (0.25 eV) of dc electrical conductivity might have been due to a short-range migration or hopping of single ionized oxygen vacancy and a long-range migration or hopping of charge carriers over the whole disordered system, respectively.

  18. 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.

  19. 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

  20. 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.

  1. Lead-free solders for electronics applications: Wetting analysis

    SciTech Connect

    Vianco, P.T.; Hosking, F.M.; Frear, D.R.

    1991-01-01

    The fabrication of electronic systems has relied upon eutectic tin-lead solder for the attachment of components to printed wiring boards. Higher service temperatures are approaching the durability limits of the eutectic solder. The tin-rich, lead-free solders are being actively studied as alternate alloys. Experiments that examined the wettability of 95Sn-5Sb (wt %), 95.5Sn-4.0Cu-0.5Ag, 96.5Sn-3.5Ag, and the control solder, 60Sn-40Pb, on oxygen-free, high conductivity copper were performed. A rosin-based, mildly activated (RMA) flux and three water soluble, organic acid fluxes were used in the wetting balance/meniscometer measurements. The 95.5Sn-4.0Cu-0.5Ag and 95Sn- 5Sb alloys exhibited good wetting, with contact angles of 35{degree} < {theta}{sub c} < 55{degree} as compared to the excellent performance of the 60Sn-40Pb material (20{degree} < {theta}{sub c} < 35{degree}). The fair wettability observed with the 96.5Sn-3.5Ag solder (60{degree} < {theta}{sub c} < 75{degree}) was due in large part to the inability of the fluxes to significantly lower the solder-flux interfacial tension. The wetting rates of the 95.5Sn-4.0Cu-0.5Ag and 95Sn-5Sb solders were comparable to those of the control; the 96. 5Sn-3.5Ag alloy wetting rate was slower than the other candidates. The solder film formed on the substrate surface by the 95.5Sn-4.0Cu-0. 5Ag alloy was very grainy. The water soluble fluxes exhibited a larger degree of residue formation than did the RMA flux. 8 refs., 12 figs.

  2. 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

  3. Enhanced magnetoelectric effects in composite of piezoelectric ceramics, rare-earth iron alloys, and shape-optimized nanocrystalline alloys

    NASA Astrophysics Data System (ADS)

    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 (Tb0.3Dy0.7Fe1.92) 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 (d33m) 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 d33m 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.

  4. 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.

  5. High-Temperature Piezoelectrics with Large Piezoelectric Coefficients

    NASA Astrophysics Data System (ADS)

    Shinekumar, K.; Dutta, Soma

    2015-02-01

    High-temperature piezoelectric materials are of interest for sensors and actuators in various industrial applications in which the devices are exposed to high temperature. A lot of research has been conducted in this area to bring forth a suitable piezoelectric material having a high Curie temperature for suitable usage at a high temperature with good piezoelectric properties. This report is an attempt to review the state of the art in high-temperature piezoelectric materials, covering their issues and concerns at elevated temperatures. Among the non-ferroelectric crystal classes, langasite and oxyborate crystals retain their piezoelectricity up to a very high temperature, but their piezoelectric coefficient is much smaller compared to a standard piezoelectric material such as lead zirconate titanate. A similar trend has also been observed in ferroelectric crystal class which shows poor piezoelectricity but retains it until a high temperature. Recent studies on solid solutions of bismuth-based oxides and lead titanate with the chemical formulae Bi(Me3+) O3-PbTiO3 and Bi(Me1Me2)O3-PbTiO3 (Me3+ represents a trivalent cation and Me1 and Me2 are cations having a combined valency of 3) show a much application potential of these materials due to improved piezoelectric property and high Curie temperature. BiScO3-PbTiO3, Bi(Mg0.5Ti0.5)O3-PbTiO3, (Bi(Ni0.5Ti0.5)O3-PbTiO3 and Bi(Zn0.5T0.5)O3-PbTiO3 are some interesting high-temperature piezoelectrics from the group of Bi(Me3+)O3-PbTiO3 and Bi(Me1Me2) O3-PbTiO3 which shows superior piezoelectric properties at high temperatures. Among the lead-free piezoelectrics, (K0.5Na0.5)NbO3 demands a special interest for further studies due to its plausible good piezoelectric property at elevated temperature.

  6. 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

  7. 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…

  8. 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.

  9. 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

  10. 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.

  11. 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 (?r and tan ?) 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.

  12. 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.

  13. 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.

  14. 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

  15. Piezoelectric valve

    DOEpatents

    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.

  16. 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.

  17. High Temperature Piezoelectric Ceramics Based on xPbTiO3-(1-x)Bi(Sc1/2Me1/4Ti1/4)O3 (Me = Zn, Mg) Ternary Perovskites

    NASA Astrophysics Data System (ADS)

    Ansell, Troy Y.; Nikkel, Jason; Cann, David P.; Sehirlioglu, Alp

    2012-10-01

    Polycrystalline xPbTiO3-(1-x)Bi(Sc1/2Me1/4Ti1/4)O3 (PT-BS-BMeT) ceramics, where Me = Mg (M) or Zn (Z), were studied for development of high temperature piezoelectrics. Ceramics were processed using standard mixed oxide procedure at various temperatures. X-ray diffraction at room temperature revealed that the tetragonality of PT-BS-BZT decreased as PbTiO3 content decreased from x = 0.90 to 0.60 and tetragonality of PT-BS-BMT decreased as PbTiO3 content decreased from x = 0.60 to 0.40. A transition was observed in PT-BS-BMT within compositions x = 0.42-0.50. Dielectric properties revealed permittivites up to ?r?20000 and transition temperatures up to 540 C. Hysteresis measurements showed full saturation below 50 mol % PbTiO3 content with remanent polarization of Pr = 32.8 C/cm2 and coercive field of 23.0 kV/cm. Converse piezoelectric coefficients (d33*) calculated from unipolar strain measurements revealed values between 240 and 313 pm/V. Depolarization temperatures were measured between 320 and 390 C.

  18. 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)

  19. Continuous cross-over from ferroelectric to relaxor state and piezoelectric properties of BaTiO3-BaZrO3-CaTiO3 single crystals

    NASA Astrophysics Data System (ADS)

    Benabdallah, F.; Veber, P.; Prakasam, M.; Viraphong, O.; Shimamura, K.; Maglione, M.

    2014-04-01

    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 (Ba0.850Ca0.150)(Ti0.900Zr0.100)O3 ceramics exhibit outstanding piezoelectric coefficients. For the first time, we report the growth of piezoelectric lead-free single crystals in the BaTiO3-BaZrO3-CaTiO3 pseudo-ternary system. The stoichiometry control in the CaO-BaO-TiO2-ZrO2 solid solution led to single crystals with various compositions ranging from (Ba0.857Ca0.143)(Ti0.928Zr0.072)O3 to (Ba0.953Ca0.047)(Ti0.427Zr0.573)O3. 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 (Ba0.838Ca0.162)(Ti0.854Zr0.146)O3 composition, which has been grown and oriented along [001] crystallographic direction, displayed electromechanical coefficients d31 and k31 of 93 pC.N-1 and 0.18, respectively, near the room temperature (T = 305 K).

  20. Piezoelectric Properties of Fine-Grained Pb(Mg1/3Nb2/3)O3-Pb(Zr,Ti)O3-Bi(Zn1/2Ti1/2)O3 Quaternary Solid Solution Ceramics

    NASA Astrophysics Data System (ADS)

    Yue, Ruifang; Hou, Xianbo; He, Wenze; Yu, Jian

    2013-06-01

    On the basis of solid state reaction eutectic behavior between Pb(Mg1/3Nb2/3)O3-Pb(Zr,Ti)O3 (PMN-PZT) and metastable perovskite-type Bi(Zn1/2Ti1/2)O3 (BZT), perovskite-structured PMN-PZT-BZT quaternary solid solution piezoceramics with various compositions were experimentally demonstrated with an intrinsic low sintering temperature in the windows of 950-1050 C. These fine-grained densified PMN-PZT-BZT ceramics were able to be poled sufficiently at room temperature through polarization-electric field hysteresis loop measurement, different from normal poling treatment with DC bias field at high temperature, which will simplify future device processing of monolithic multilayer piezoceramic transducers. A typical piezoelectric property of dielectric constant ?33T/?0 = 3471, piezoelectric constant d33 = 480 pC/N, planar coupling coefficient kp = 0.41, thickness coupling coefficient kt = 0.50, mechanical quality factor Qm = 68 and relaxor ferroelectric phase transition temperature Tm = 167 C at 1 MHz was obtained for the fine-grained densified Pb0.96Sr0.04(Mg1/3Nb2/3)0.37Zr0.24Ti0.39O3+3%Bi(Zn0.5Ti0.5)O3+2%NiO ceramics sintered at 1020 C, which is much promising to manufacture monolithic multilayer piezoelectric transducers with Ag95/Pd5 as inner electrode material.

  1. Mitigation of thermal and fatigue behavior in K0.5Na0.5NbO3-based lead free piezoceramics

    PubMed Central

    Zhang, Shujun; Xia, Ru; Hao, Hua; Liu, Hanxing; Shrout, Thomas R.

    2008-01-01

    K0.5Na0.5NbO3-(KNN) based lead free materials have been found to exhibit good piezoelectric properties (d33?250 pC?N) due to the orthorhombic-tetragonal polymorphic phase transition (PPT) temperature compositionally shifted downward to near room temperature. However, associated with the PPT are issues of temperature and domain instability, making them impractical for applications. In this work, CaTiO3 (CT) was used to effectively shift the PPT downward in effort to mitigate these issues. As expected, CT modified KNN based materials exhibited nearly temperature independent properties (?50?200 C) and fatigue-free behavior, together with its relatively high d33 value of ?200 pC?N, make the CT modified KNN based materials excellent candidates for lead free actuators and transducers. PMID:19479047

  2. 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.

  3. 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

  4. Enhanced high-temperature piezoelectric properties of traditional Pb(Zr,Ti)O3 ceramics by a small amount substitution of KNbO3

    NASA Astrophysics Data System (ADS)

    Pan, Zhao; Chen, Jun; Fan, Longlong; Rong, Yangchun; Zheng, Shaoying; Liu, Laijun; Fang, Liang; Xing, Xianran

    2014-12-01

    Crystal structure, piezoelectric, and dielectric properties were investigated on the (1-x)Pb(Zr0.54Ti0.46)O3-xKNbO3 system. The piezoelectric properties have been significantly improved by substituting a small amount of KNbO3. In the morphotropic phase boundary (x = 0.015), the compound not only shows enhanced piezoelectric coefficient d33 = 450 pC/N, which is two times larger than that of unmodified Pb(Zr,Ti)O3 (d33 = 223 pC/N), but also the Curie temperature (TC = 380 C) is still well maintained at a high level. This phenomenon challenges our general knowledge that in piezoelectric materials the Curie temperature and piezoelectric properties are mutually contradictory. It should be noted that a giant total strain as high as 0.73% is also observed. The high thermal depoling temperature more than 300 C combined with the excellent piezoelectric properties suggest it as a potential candidate for high temperature actuators and sensors applications.

  5. 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.

  6. 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.

  7. 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.

  8. Room temperature nonlinear magnetoelectric effect in lead-free and Nb-doped AlFeO3 compositions

    NASA Astrophysics Data System (ADS)

    Ctica, Luiz F.; Santos, Guilherme M.; Freitas, Valdirlei F.; Coelho, Adelino A.; Pal, Madhuparna; Santos, Ivair A.; Garcia, Ducinei; Eiras, Jos A.; Guo, Ruyan; Bhalla, Amar S.

    2015-02-01

    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 (AlFeO3), 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 AlFeO3 and 2 at. % Nb-doped AlFeO3 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 Hbias suggests a room temperature nonlinear magnetoelectric coupling in both single-phase and Nb-doped AlFeO3-based ceramic compositions.

  9. 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.

  10. 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

  11. 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

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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)

  18. Comprehensive investigation of elastic and electrical properties of Li/Ta-modified (K,Na)NbO3 lead-free piezoceramics

    NASA Astrophysics Data System (ADS)

    Yao, Fang-Zhou; Wang, Ke; Li, Jing-Feng

    2013-05-01

    A full set of elastic and electrical coefficients of (K,Na)NbO3-based lead-free piezoceramics with a nominal composition of Li0.03(K0.48Na0.52)0.97(Nb0.8Ta0.2)O3 (abbreviated as KNNLT) was evaluated by the standard resonance method, and compared to those of K4CuNb8O23 doped (K0.45Na0.55)NbO3 (KNN-KCN) as well as typical Pb(Zr,Ti)O3-based piezoceramics PZT5A. The measurement of intermediate elastic stiffness and compliance coefficients of KNNLT indicated that KNNLT is elastically "softer" than KNN-KCN but "harder" than PZT5A. An extremely high piezoelectric stiffness coefficient h33 = 68.8 108 V/m was obtained, due to an especially low clamped dielectric constant ?33S of 361. And a large longitudinal electromechanical coupling factor k33 = 57% was observed in the KNNLT system. Furthermore, the piezoelectric coefficient d33 of KNNLT was characterized via three distinctive methods: the resonance method, the Berlincourt method, and the converse piezoelectric strain measurement; while these three techniques yielded values of 174 pC/N, 195 pC/N, and 308 pm/V, respectively. The difference in d33 values determined by the three methods may be attributed to different measurement frequencies and extrinsic piezoelectric contributions related to domain wall vibration and domain switching. Besides, the piezoelectric performances of KNNLT piezoceramics were found insensitive to frequency but susceptible to temperature and electric field cycling.

  19. 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.

  20. 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 ?C/cm2 (2Pr ? 31.4 ?C/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.

  1. The micro-droplet behavior of a molten lead-free solder in an inkjet printing process

    NASA Astrophysics Data System (ADS)

    Tsai, M. H.; Hwang, W. S.; Chou, H. H.

    2009-12-01

    An experimental investigation on the droplet formation of molten Sn3.0 wt%Ag0.5 wt%Cu alloy by an inkjet printing process was conducted. The printing process used a piezoelectric print head with a nozzle orifice diameter of 50 m. Micro-droplets of a molten lead-free solder were ejected at 230 C. The print head was driven by a bipolar pulse 40 V in amplitude. The major variables for this study were two pulse times; trise/tfinalrise and tfall, as well as N2 back-pressure in the molten solder reservoir. Under various printing conditions, extrusion of the liquid column, contraction of liquid thread and pinch-off of liquid thread at nozzle exit were observed by monitoring the dynamics of the molten solder droplet ejection process. The droplet formation was found to be insensitive to trise and tfinalrise in the range of 250-1000 s. The behavior of droplet formation was, however, significantly affected by the transfer rate, tfall, in the range of 30-60 s and tfall of 50 s yielded the most desirable condition of single droplet formation. The N2 back-pressure was also found to be critical, where a back pressure between 10 and 21 kPa could give the desirable single-droplet formation condition.

  2. 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

  3. 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.

  4. 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.

  5. Piezoelectric Energy Harvester for Batteryless Switch Devices

    NASA Astrophysics Data System (ADS)

    Kim, Min-Soo; Lee, Sung-Chan; Kim, Sin-Woong; Jeong, Soon-Jong; Kim, In-Sung; Song, Jaesung

    2013-10-01

    This study investigated a piezoelectric energy-harvesting system for a mechanical switch device. Piezoelectric ceramics of 0.4Pb(Mg1/3Nb2/3)O3-0.25PbZrO3-0.35PbTiO3 were prepared by using a conventional solid-state reaction method. Li2O, Bi2O3, and CuO additions were used as sintering aids to develop piezoelectric ceramics for low-temperature sintering. Multilayer piezoelectric ceramics with 10103 mm3 sizes and with Ag-Pd inner electrodes were manufactured by using the conventional tape-casting method with the prepared powder. A prototype of a piezoelectric batteryless switch device using the multilayer ceramics was produced. It showed an output peak-to-peak voltage of 3.8 V and an output power per strike of 18 W. The performance of the device was good enough for practical use.

  6. Highly piezoelectric Biocompatible and Soft Composite Fibers

    NASA Astrophysics Data System (ADS)

    Jakli, Antal; Morvan, Jason; Buyuktanir, Ebru; West, John

    2012-02-01

    We report the fabrication of highly piezoelectric biocompatible soft fibers containing Barium Titanate (BT) ferroelectric ceramic particles dispersed in electrospun poly lactic acid (PLA). These fibers form mats that have two orders of magnitude larger piezoelectric constant per weight than single crystal barium titanate films. We demonstrate that the observed super-piezoelectricity results from the electrospinning induced polar alignment of the ferroelectric particles and the increased surface area compared to single crystal films. Due to the biocompatibility of PLA that encases the ferroelectric particles, these mats can be applied even in biological applications such as bio-sensors, artificial muscles and energy harvesting devices.

  7. Highly piezoelectric biocompatible and soft composite fibers

    NASA Astrophysics Data System (ADS)

    Morvan, J.; Buyuktanir, E.; West, J. L.; Jkli, A.

    2012-02-01

    We report the fabrication of highly piezoelectric biocompatible soft fibers containing barium titanate ferroelectric ceramic particles dispersed in electrospun poly lactic acid (PLA). These fibers form mats that have two orders of magnitude larger piezoelectric constant per weight than single crystal barium titanate films. We propose that the observed apparent piezoelectricity results from the electrospinning induced polar alignment of the ferroelectric particles that pole the fibers similar to ferroelectret polymer foams that are poled by corona discharge. Due to the biocompatibility of PLA that encases the ferroelectric particles, these mats can be used in biological applications such as bio-sensors, artificial muscles, and energy harvesting devices.

  8. 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.

  9. 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.

  10. 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

  11. Dielectric and magnetic coupling in lead-free FeAlO 3 magnetoelectric compound

    NASA Astrophysics Data System (ADS)

    Ctica, L. F.; Santos, I. A.; Venet, M.; Garcia, D.; Eiras, J. A.; Coelho, A. A.

    2008-07-01

    A lead-free FeAlO 3 multiferroic magnetoelectric compound was obtained through the sol-gel technique with subsequent annealing in an oxidative atmosphere. Dielectric investigations revealed a frequency- and temperature-dependent dielectric anomaly, which can be probably coupled to the sample magnetic ordering at around 220 K. These results indicate that the lead-free FeAlO 3 magnetoelectric compound, which has a lower environmental impact in comparison to other multiferroics, is a potential candidate to be employed in areas where the magnetoelectric effect can be exploited.

  12. 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.

  13. 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

  14. 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

  15. 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.

  16. 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% ...

  17. 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.

  18. 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...

  19. 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...

  20. 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.

  1. 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.

  2. 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.

  3. Ferroelastic Characterization of Piezoelectrics

    NASA Astrophysics Data System (ADS)

    Fett, T.

    The elastic deformation behavior of an isotropic material is governed by Young's modulus Y and Poisson's ratio ?. Knowledge of the Young's modulus, for instance, is necessary to split the total deformation S i measured under load stress T i into elastic S {/i el} and "plastic" S {/i pl} strain contributions S_i = S_i^el + S_i^pl = {T_i over Y} + S_i^pl , where Y is not necessarily a constant, but may depend on the amount of nonelastic strains, as will be shown later. The methods for the determination of the Young's moduli, well-known from conventional ceramics and also applicable to unpoled piezoelectric materials, are much more complicated for nonisotropic materials due to the tensorial character of the modulus and the special electric boundary conditions [1]. The conditions of a constant electrical field, E z ? E 3 = const, or a constant dielectric displacement, D z ? E 3 = const, influence the elastic properties. This effect may be illustrated for a uniaxial stress state with T x ? T 1 ? 0 exclusively. In the case of a piezoelectric material, we are interested in the components D_3 = d_{31}T_1 + \\varepsilon_{33}^T E_3 .

  4. Prototyping lead-free solders on hand-soldered, through-hole circuit boards

    SciTech Connect

    Vianco, P.T.; Mizik, P.M.

    1993-12-31

    The lead-free solders 96.5Sn-3.5Ag (wt %), 95.5Sn-4.0Cu-0.5Ag, 91. 84Sn-3.33Ag-4.83Bi were used in the assembly of a through-hole circuit board to determine the feasibility of their suitability in hand soldering processes. Prototypes assembled with 63Sn-37Pb solder were manufactured to serve as control units. Implementation of the lead-free alloys were performed with a rosin-based, mildly activated (RMA) flux and a 700{degree}F soldering tip. A procedure was developed to remove the tin-lead finish from the leaded components and replace it with a 100Sn hot dipped coating. Assembly feasibility was demonstrated for all three lead-free solders. Defect counts were greater than observed with the tin-lead control alloy; however, the number of defects diminished with experience gained by the operator. Visual examination of the solder joints indicated satisfactory wetting of both the device leads and circuit board land with no apparent damage to the underlying laminate nor to the device packages. Cross sections of the lead-free solder joints showed that the were more susceptible to void formation within the holes than was the case with the tin-lead solder. Some cracking was observed at the interface between the Sn-Ag-Bi solder and the copper lands; the relatively high strength of this solder and fast cooling rate of the hand assembly process was believed responsible for this defect.

  5. 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.

  6. Logistics for the implementation of lead-free solders on electronic assemblies

    SciTech Connect

    Vianco, P.T.; Artaki, I.

    1993-12-31

    The prospects of legislative and regulatory action aimed at taxing, restricting or banning lead-bearing materials from manufactured products has prompted the electronics community to examine the implementation of lead-free solders to replace currently used lead-containing alloys in the manufacture of electronic devices and assemblies. The logistics for changing the well established ``tin-lead solder technology`` require not only the selection of new compositions but also the qualification of different surface finishes and manufacturing processes. The meniscometer/wetting balance technique was used to evaluate the wettability of several candidate lead-free solders as well as to establish windows on processing parameters so as to facilitate prototype manufacturing. Electroplated and electroless 100Sn coatings, as well as organic preservatives, were also examined as potential alternative finishes for device leads and terminations as well as circuit board conductor surfaces to replace traditional tin-lead layers. Sandia National Laboratories and AT&T have implemented a program to qualify the manufacturing feasibility of surface mount prototype circuit boards using several commercial lead-free solders by infrared reflow technology.

  7. [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

  8. Diffuse phase transition in Li{sub 0.12}Na{sub 0.88}NbO{sub 3} piezoelectric ceramics

    SciTech Connect

    Mitra, Supratim; Kulkarni, Ajit R.; Prakash, Om

    2013-02-05

    The morphotropic phase boundary composition viz. lithium sodium niobate, Li{sub 0.12}Na{sub 0.88}NbO{sub 3}, (LNN-12) was prepared by conventional solid state reaction and sintering route. The temperature dependent permittivity response near transition temperature showed a diffused phase transition (DPT). The degree of diffuseness, {gamma}, using the modified Curie-Weiss law, was found to be 1.92, indicative of almost-complete diffuse phase transition. The planar coupling constant k{sub p}, and mechanical quality factor Q{sub m}, measured by resonance-antiresonance method, were 0.17 and 413 respectively. These parameter values make LNN-12 ceramic an attractive candidate for transducers applications.

  9. 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

  10. 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.

  11. 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.

  12. Nanoscale Insight into Lead-Free BNT-BT-xKNN

    SciTech Connect

    Dittmer, Robert; Jo, Wook; Rdel, Jrgen; 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.

  13. 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

  14. 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.

  15. Effect of gamma radiation on micromechanical hardness of lead-free solder joint

    NASA Astrophysics Data System (ADS)

    Paulus, Wilfred; Rahman, Irman Abdul; Jalar, Azman; Kamil, Insan; Yusoff, Wan Yusmawati Wan; Bakar, Maria Abu

    2015-09-01

    Lead-free solders are important material in nano and microelectronic surface mounting technology for various applications in bio medicine, environmental monitoring, spacecraft and satellite instrumentation. Nevertheless solder joint in radiation environment needs higher reliability and resistance to any damage caused by ionizing radiations. In this study a lead-free 99.0Sn0.3Ag0.7Cu wt.% (SAC) solder joint was developed and subjected to various doses of gamma radiation to investigate the effects of the ionizing radiation to micromechanical hardness of the solder. Averaged hardness of the SAC joint was obtained from nanoindentation test. The results show a relationship between hardness values of indentations and the increment of radiation dose. Highest mean hardness, 0.2290 0.0270 GPa was calculated on solder joint which was exposed to 5 Gray dose of gamma radiation. This value indicates possible radiation hardening effect on irradiated solder. The hardness gradually decreased to 0.1933 0.0210 GPa and 0.1631 0.0173 GPa when exposed to doses 50 and 500 gray respectively. These values are also lower than the hardness of non irradiated sample which was calculated as 0.2084 0.0.3633 GPa indicating possible radiation damage and needs further related atomic dislocation study.

  16. Assembly feasibility and reliability studies of surface mount circuit boards manufactured with lead-free solders

    SciTech Connect

    Vianco, P.T.; Artaki, I.; Jackson, A.M.; Sampala, J.H.

    1994-06-01

    Manufacturing feasibility and reliability evaluations were performed on circuit board test vehicles assembled with the lead-free solders 96.5Sn-3.5Ag (T{sub eut} = 221C) and 58Bi-42Sn (T{sub eut} = 138C). Manufacturability was assessed by defect analysis of the test vehicles. The reliability evaluation was performed by thermal cycling selected test vehicles for 1000, 2500, and 5000 cycles (0C-100C and 30 min cycles); the quantitative and qualitative metrics were solder joint strength and joint microstructure, respectively. Both lead-free solders demonstrated adequate assembly performance. A slightly reduced degree of spreading (wetting) was the predominant defect which was largely attributed to nonoptimized paste components. Fatigue damage in the form of grain boundary and/or phase boundary sliding resulted from thermal cycling of the 96.5Sn-3.5Ag and 58Bi-42Sn solder joints. The damage was distributed primarily in the solder located between the lead or termination and the pad. The absence of well developed cracks allowed the joints to maintain structural integrity, even when fatigue damage was appreciable.

  17. 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.

  18. 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.

  19. 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.

  20. 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

  1. Enhanced piezoelectric performance of composite sol-gel thick films evaluated using piezoresponse force microscopy

    PubMed Central

    Liu, Yuanming; Lam, Kwok Ho; Kirk Shung, K.; Li, Jiangyu; Zhou, Qifa

    2013-01-01

    Conventional composite sol-gel method has been modified to enhance the piezoelectric performance of ceramic thick films. Lead zirconate titanate (PZT) and lead magnesium niobatelead 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

  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 1260C. 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 ?C/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. 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.

  4. Strong ultrasonic microwaves in ferroelectric ceramics.

    PubMed

    Arlt, G

    1998-01-01

    It is well known that ferroelectric materials have piezoelectric properties which allow the transformation of electrical signals into mechanical signals and vice versa. The transducer action normally is restricted to frequencies up to the mechanical resonance frequency of the sample. There are, however, two mechanisms which allow transducer action in ferroelectric ceramics at much higher frequencies: one is the normal piezoelectric effect in a ferroelectric ceramic in which the crystallites have periodic domain structures, the other is a domain wall effect in which ferroelastic domain walls in a periodic domain structure are powerful shear wave emitters. Both mechanisms give rise to extensive dielectric losses in ceramics at microwave frequencies. PMID:18244152

  5. 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.

  6. Solderability of melting lead-free solder to tiny joint of electronic products

    NASA Astrophysics Data System (ADS)

    Chen, Fang; Du, Changhua; Du, Yunfei

    2005-12-01

    The behavior of melting solder has an important influence on the tiny joints of electronic products. In order to improve the properties of lead-free solder, a Sn-3.5Ag0.6Cu alloy was smelted using traditional and a modified technology, respectively. The solderability of the two alloys were investigated using a wetting balance method for the different conditions. The test results showed that the modified solder had good solderability, where the excellent flux used was rosin-ethanol or rosin-isopropanol solution. In experimental condition, when the added active agent is 0.4% of rosin mass or 0.1% of solution mass, the wetting velocity and wetting force can be improved 5 times and 1.5 times, respectively. The best soldering parameters are temperature levels less than or equal to 270, and the soakage time in 2-3s.

  7. Retarding Electromigration in Lead-Free Solder Joints by Alloying and Composite Approaches

    NASA Astrophysics Data System (ADS)

    Zhao, Ran; Ma, Limin; Zuo, Yong; Liu, Sihan; Guo, Fu

    2013-02-01

    The voids induced by electromigration (EM) can trigger serious failure across the entire cathode interface of solder joints. In this study, alloying and composite approaches showed great potential for inhibiting EM in lead-free solder joints. Microsized Ni, Co, and Sb particles were added to the solder matrix. Cu and Sn particles were added to the melting solder to form in situ Cu6Sn5, which formed a barrier layer in the underbump metallization of flip-chip solder joints. The polarity effect induced by EM was observed to be significantly inhibited in the alloyed and composite solder joints. This indicates that the Sn-Ni, Sn-Co, Sn-Sb, and Cu6Sn5 intermetallic compounds may act as barriers to obstruct the movement of the dominant diffusion species along phase boundaries, which in turn improves the resistance to EM. However, Sb particles could induce crack formation and propagation that might lead to joint fracture.

  8. 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.

  9. 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-?m-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

  10. 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.

  11. 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.

  12. 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

  13. Evaluation of Mechanical Losses in Piezoelectric Plates using Genetic algorithm

    NASA Astrophysics Data System (ADS)

    Arnold, F. J.; Gonalves, 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.

  14. [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

  15. Phase transitions and electrical behavior of lead-free (K{sub 0.50}Na{sub 0.50})NbO{sub 3} thin film

    SciTech Connect

    Wu Jiagang; Wang, John

    2009-09-15

    Lead-free (K{sub 0.50}Na{sub 0.50})NbO{sub 3} (KNN) thin films with a high degree of (100) preferred orientation were deposited on the SrRuO{sub 3}-buffered SrTiO{sub 3}(100) substrate by off-axis radio frequency magnetron sputtering. They possess lower phase transition temperatures (T{sub o-t}approx120 deg. C and T{sub c}approx310 deg. C), as compared to those of KNN bulk ceramic (T{sub o-t}approx190 deg. C and T{sub c}approx400 deg. C). They also demonstrate enhanced ferroelectric behavior (e.g., 2P{sub r}=24.1 muc/cm{sup 2}) and fatigue endurance, together with a lower dielectric loss (tan deltaapprox0.017) and a lower leakage current, as compared to the bulk ceramic counterpart. Oxygen vacancies are shown to be involved in the conduction of the KNN thin film.

  16. Variable pulse width piezoelectric ultrasonic transducer driver

    NASA Astrophysics Data System (ADS)

    Martin, R.

    1983-11-01

    Requirements of ceramic piezoelectric ultrasonic transducer drive circuits are discussed in the light of today's advanced nondestructive testing techniques. A new drive circuit based upon power MOSFET devices, which overcomes many of the shortcomings of capacitor discharge circuits, is described. This new driving technique enables transducers of a wide range of resonant frequencies to be driven from a simple drive unit. It also enables transducer characteristics to be optimized for particular applications by control of the drive pulse shape.

  17. 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).

  18. 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.

  19. Piezoelectric ultrasonic motors

    SciTech Connect

    Wallaschek, J.

    1994-12-31

    Piezoelectric ultrasonic motors are a new type of actuator. They are characterized by high torque at low rotational speed, simple mechanical design and good controllability. They also provide a high holding torque even if no power is applied. Compared to electromagnetic actuators the torque per volume ratio of piezoelectric ultrasonic motors can be higher by an order of magnitude. Recently various types of piezoelectric ultrasonic motors have been developed for industrial applications. This paper describes several types of piezoelectric ultrasonic motors.

  20. 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.

  1. 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.

  2. 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.

  3. "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.

  4. 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

  5. Integration of lead-free ferroelectric on HfO2/Si (100) for high performance non-volatile memory applications

    NASA Astrophysics Data System (ADS)

    Kundu, Souvik; Maurya, Deepam; Clavel, Michael; Zhou, Yuan; Halder, Nripendra N.; Hudait, Mantu K.; Banerji, Pallab; Priya, Shashank

    2015-02-01

    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.

  6. 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

  7. Direct Piezoelectricity of Soft Composite Electrospun Fibers

    NASA Astrophysics Data System (ADS)

    Varga, Michael; Morvan, Jason; Diorio, Nick; Buyuktanir, Ebru; Harden, John; West, John; Jakli, Antal

    2013-03-01

    Recently soft fiber mats electrospun from solutions of Barium Titanate (BT) ferroelectric ceramics particles and poly lactic acid (PLA) were found to have large (d33 1nm/V) converse piezoelectric signals offering a myriad of applications ranging from active implants to smart textiles. Here we report direct piezoelectric measurements (electric signals due to mechanical stress) of the BT/PLA composite fiber mats at various BT concentrations. A testing apparatus was designed and constructed solely for these measurements involving AC stresses provided by a speaker in 10Hz-10kHz frequency range. The piezoelectric constant d33 ~1nC/N was found to be in agreement with the prior converse piezoelectric measurements. The largest signals were obtained with 6% BT/PLA composites, probably because the BT particles at higher concentrations could not be dispersed homogeneously. Importantly the direct piezoelectric signal is large enough to power a small LCD by simply pressing a 0.2mm thick 2 cm2 area mat by a finger. We expect to use these mats in active Braille cells and in liquid crystal writing tablets.

  8. 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.

  9. 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.

  10. A novel high-speed shear test for lead-free flip chip packages

    NASA Astrophysics Data System (ADS)

    Huh, Seok-Hwan; Kim, Kang-Dong; Kim, Keun-Soo; Jang, Joong-Soon

    2012-02-01

    Despite the importance of lead-free solders in modern environmentally friendly packaging, few studies have been conducted on their mechanical reliability at the wafer level. In the present study, high-speed die shear tests were conducted to investigate the effects of strain rate on the shearing resistance and fracture mode of Sn-3wt%Ag-0.5wt%Cu solder joints on electroless Ni-P/immersion Au surface finish pads. The results indicated that the solder joints underwent ductile and mixed ductile-brittle fracture at low (<855 s-1) and high (>25,385 s-1) strain rates, respectively. Thus, the overall shear stress-strain curve can be divided into three areas according to Hollomon's law, starting from low strain rates: area I, 100% ductile fracture of the solder itself; area II, mixed ductile-brittle fracture resulting in a ductile-brittle transition region; and area III, 100% brittle fracture at the interface between the intermetallic compound and the Ni-P layer.

  11. Methylammonium Bismuth Iodide as a Lead-Free, Stable Hybrid Organic-Inorganic Solar Absorber.

    PubMed

    Hoye, Robert L Z; Brandt, Riley E; Osherov, Anna; Stevanovi?, Vladan; Stranks, Samuel D; Wilson, Mark W B; Kim, Hyunho; Akey, Austin J; Perkins, John D; Kurchin, Rachel C; Poindexter, Jeremy R; Wang, Evelyn N; Bawendi, Moungi G; Bulovi?, Vladimir; Buonassisi, Tonio

    2016-02-01

    Methylammonium lead halide (MAPbX3 ) perovskites exhibit exceptional carrier transport properties. But their commercial deployment as solar absorbers is currently limited by their intrinsic instability in the presence of humidity and their lead content. Guided by our theoretical predictions, we explored the potential of methylammonium bismuth iodide (MBI) as a solar absorber through detailed materials characterization. We synthesized phase-pure MBI by solution and vapor processing. In contrast to MAPbX3 , MBI is air stable, forming a surface layer that does not increase the recombination rate. We found that MBI luminesces at room temperature, with the vapor-processed films exhibiting superior photoluminescence (PL) decay times that are promising for photovoltaic applications. The thermodynamic, electronic, and structural features of MBI that are amenable to these properties are also present in other hybrid ternary bismuth halide compounds. Through MBI, we demonstrate a lead-free and stable alternative to MAPbX3 that has a similar electronic structure and nanosecond lifetimes. PMID:26866821

  12. Discovering lead-free perovskite solar materials with a split-anion approach.

    PubMed

    Sun, Yi-Yang; Shi, Jian; Lian, Jie; Gao, Weiwei; Agiorgousis, Michael L; Zhang, Peihong; Zhang, Shengbai

    2016-03-17

    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. PMID:26349623

  13. Characterization of Low-Melting-Point Sn-Bi-In Lead-Free Solders

    NASA Astrophysics Data System (ADS)

    Li, Qin; Ma, Ninshu; Lei, YongPing; Lin, Jian; Fu, HanGuang; Gu, Jian

    2016-02-01

    Development of lead-free solders with low melting temperature is important for substitution of Pb-based solders to reduce direct risks to human health and the environment. In the present work, Sn-Bi-In solders were studied for different ratios of Bi and Sn to obtain solders with low melting temperature. The microstructure, thermal properties, wettability, mechanical properties, and reliability of joints with Cu have been investigated. The results show that the microstructures of the Sn-Bi-In solders were composed of β-Sn, Bi, and InBi phases. The intermetallic compound (IMC) layer was mainly composed of Cu6Sn5, and its thickness increased slightly as the Bi content was increased. The melting temperature of the solders was around 100°C to 104°C. However, when the Sn content exceeded 50 wt.%, the melting range became larger and the wettability became worse. The tensile strength of the solder alloys and solder joints declined with increasing Bi content. Two fracture modes (IMC layer fracture and solder/IMC mixed fracture) were found in solder joints. The fracture mechanism of solder joints was brittle fracture. In addition, cleavage steps on the fracture surface and coarse grains in the fracture structure were comparatively apparent for higher Bi content, resulting in decreased elongation for both solder alloys and solder joints.

  14. Developing a NASA Lead-Free Policy for Electronics - Lessons Learned

    NASA Technical Reports Server (NTRS)

    Sampson, Michael J.

    2008-01-01

    The National Aeronautics and Space Administration (NASA) is not required by United States or international law to use lead-free (Pb-free) electronic systems but international pressure in the world market is making it increasingly important that NASA have a Pb-free policy. In fact, given the international nature of the electronics market, all organizations need a Pb-free policy. This paper describes the factors which must be taken into account in formulating the policy, the tools to aid in structuring the policy and the unanticipated and difficult challenges encountered. NASA is participating in a number of forums and teams trying to develop effective approaches to controlling Pb-free adoption in high reliability systems. The activities and status of the work being done by these teams will be described. NASA also continues to gather information on metal whiskers, particularly tin based, and some recent examples will be shared. The current lack of a policy is resulting in "surprises" and the need to disposition undesirable conditions on a case-by-case basis. This is inefficient, costly and can result in sub-optimum outcomes.

  15. Tin pest in Sn-0.5 wt.% Cu lead-free solder

    NASA Astrophysics Data System (ADS)

    Kariya, Yoshiharu; Williams, Naomi; Gagg, Colin; Plumbridge, William

    2001-06-01

    Tin pest (the product of the allotropic transformation of β-tin into α-tin at temperatures below 286 K) has been observed in a Sn-0.5 wt.% Cu solder alloy. Some 40 percent of the specimen surface was transformed into gray tin after aging at 255K for 1.5 years, and after 1.8 years, the proportion increased to about 70 percent. The degree of transformation in work-hardened areas is much higher than in other areas, suggesting residual stress might provide an additional driving force for the transformation into α-tin. The allotropic change results in a 26 percent increase in volume, and cracks are initiated to accommodate the changes in volume. Results indicate that tin pest could lead to total disintegration of micro-electronic solder joints. The tin-copper eutectic system may become a prominent lead-free solder, and tin pest could have major ramifications on service lifetime of electronic assemblies.

  16. In Situ Synchrotron Characterization of Melting, Dissolution, and Resolidification in Lead-Free Solders

    NASA Astrophysics Data System (ADS)

    Zhou, Bite; Bieler, Thomas R.; Wu, Guilin; Zaefferer, Stefan; Lee, Tae-Kyu; Liu, Kuo-Chuan

    2012-02-01

    Melting and solidification of SAC 305 lead-free solder joints in a wafer-level chip-scale package were examined in situ with synchrotron x-ray diffraction. The chips with balls attached (but not assembled to a circuit board) were reflowed one to three times using a temperature and time history similar to an industrial reflow process. Diffraction patterns from the same joint were collected every 0.5 s during the melting and solidification process. The solidification of the Sn phase in the solder joint occurred between 0.5 s and 1 s. During melting, most of the Sn melted in about 0.5 s, but in some cases took 2-5 s for the Sn peak to completely disappear. In one instance, the Sn peak persisted for 30 s. The Ag3Sn peaks dissolved in about 1-2 s, but the Cu6Sn5 peaks from the interface were persistent and did not change throughout the melting and solidification process. Completely different Sn crystal orientations were always developed upon resolidification.

  17. In Situ Synchrotron Characterization of Melting, Dissolution, and Resolidification in Lead-Free

    SciTech Connect

    Zhou, Bite; Bieler, Thomas R.; Wu, Guilin; Zaefferer, Stefan; Lee, Tae-Kyu; Liu, Kuo-Chuan

    2013-04-08

    Melting and solidification of SAC 305 lead-free solder joints in a wafer-level chip-scale package were examined in situ with synchrotron x-ray diffraction. The chips with balls attached (but not assembled to a circuit board) were reflowed one to three times using a temperature and time history similar to an industrial reflow process. Diffraction patterns from the same joint were collected every 0.5 s during the melting and solidification process. The solidification of the Sn phase in the solder joint occurred between 0.5 s and 1 s. During melting, most of the Sn melted in about 0.5 s, but in some cases took 2-5 s for the Sn peak to completely disappear. In one instance, the Sn peak persisted for 30 s. The Ag{sub 3}Sn peaks dissolved in about 1-2 s, but the Cu{sub 6}Sn{sub 5} peaks from the interface were persistent and did not change throughout the melting and solidification process. Completely different Sn crystal orientations were always developed upon resolidification.

  18. First-Principles Investigations of Lead-Free Formamidinium Based Hybrid Perovskites

    NASA Astrophysics Data System (ADS)

    Murat, Altynbek; Schwingenschlgl, Udo

    2015-03-01

    Hybrid organic-inorganic perovskite solar cells have recently emerged as the next-generation photovoltaic technology. Most of the research work has been focused on the prototype MAPbI3 perovskite (MA = Methylammonium = CH3NH3+) and its analogues that have lead to power conversion efficiencies in excess of 15%. Despite the huge success, these materials are still non-optimal in terms of optical absorption where the bandgaps are greater than 1.6 eV as well as the toxicology issue of lead. Thus, investigation and development of lead-free perovskites with bandgaps closer to optimal, allowing greater spectral absorption, is of great interest. In this work, we perform first principles calculations to study the structural, optical, and electronic properties of new derivatives of MAPbI3 in which the organic MA cation is replaced by other organic amines of similar size such as Formamidinium (FA) and/or the Pb cation replaced by similar elements such as Sn. In particular, we investigate the role and effect of FA and Pb cations on the electronic and optical properties and analyze to which extend the bandgaps can be tuned.

  19. Fracture Toughness Enhancements in Carbon Nanotube Reinforced Ceramic Matrix Composites

    NASA Technical Reports Server (NTRS)

    Hurst, Janet

    2003-01-01

    Determine whether benefits may be derived from the addition of nanotubes to ceramic matrix composites for the high temperature /structural applications that are of interest to NASA. These include - coating, fuel sell, "smart" engine components, sensors, piezoelectrics, etc.

  20. Development of lead-free copper alloy-graphite castings. Technical report, January 1994--December 1994

    SciTech Connect

    Rohatgi, P.K.

    1995-07-01

    Water model experiments were conducted to develop a two-stage stirring method for obtaining higher yields and a more uniform distribution of graphite particles in copper alloys. This was followed by several melts for synthesis of copper-graphite alloys in which Ti was used as a wetting agent to improve the wettability of graphite in the copper melt. In the first stage, a vortex method was employed to facilitate the addition of graphite particles into the copper melt. In the second stage, a specially designed stirrer was used for uniform particle distribution while avoiding the formation of vortex in the melt. The two-stage stirring was found to considerably improve the recovery of graphite, over those obtained with the prior practice of single-stage stirring and resulting in a more uniform particle distribution. In addition, graphite recoveries increased with increasing Ti content in the range investigated. Floatation, fluidity, and directional solidification experiments were also conducted on copper-graphite alloys synthesized in this study. Fluidity tests showed that the spiral fluidity length of the yellow brass alloy increased with temperature and decreased with graphite. The fluidity of copper-graphite alloys investigated to-date remained adequate to make a variety of castings. The observations of casting microstructure under directional solidification and floatation showed that in certain castings the graphite particles remained agglomerated, and they readily floated to the upper part of the castings where they reduced the size of gains. However, even in the agglomerated form, the graphite particles improved the machinability of copper alloys in a manner similar to lead. The results of the first year work provide an improved method of synthesis of lead free copper graphite alloys with improved machinability and adequate fluidity.

  1. Development of lead-free copper alloy-graphite casting. Annual report, January--December 1994

    SciTech Connect

    Rohatgi, P.K.

    1996-02-01

    Water model experiments were conducted to develop a two-stage stirring method for obtaining higher yields and a more uniform distribution of particles in copper alloys. This was followed by several melts for synthesis of copper-graphite alloys in which T1 was used as a wetting agent to improve the wettability of graphite in the copper melt. In the first stage, a vortex method was employed to facilitate the suction of graphite particles into the copper melt. In the second stage, the specially designed stirrer was used to avoid the formation of vortex in melt. The two stage stirring was found to considerably improve the recovery of graphite, over those obtained with the prior practice of single stage stirring. In addition, graphite recoveries increased with increasing Ti content. Flotation, fluidity, and directional solidification experiments were also conducted on copper-graphite alloys synthesized in this study. Tests showed that the spiral fluidity length of the yellow brass alloy increased with temperature and decreased with graphite. The fluidity of copper-graphite alloys investigated to date remained adequate to make a variety of castings. The observations of microstructure of directional solidification and flotation showed that in certain castings the graphite particles were agglomerated and they float to the upper part of the castings where they reduced the size of grains. However, in the agglomerated form, the graphite particles improved the machinability of copper alloys in a manner similar to lead. The result of the first years work provide an improved method of synthesis of lead free copper graphite alloys with improved machinability and adequate fluidity. Future work will continue to further improve the distribution of graphite particles in casting while retaining adequate fluidity and improved machinability. Techniques like centrifugal casting will be developed to concentrate graphite in regions where it is required for machinability in bearings.

  2. Lead-Free MA2CuClxBr4-x Hybrid Perovskites.

    PubMed

    Cortecchia, Daniele; Dewi, Herlina Arianita; Yin, Jun; Bruno, Annalisa; Chen, Shi; Baikie, Tom; Boix, Pablo P; Grätzel, Michael; Mhaisalkar, Subodh; Soci, Cesare; Mathews, Nripan

    2016-02-01

    Despite their extremely good performance in solar cells with efficiencies approaching 20% and the emerging application for light-emitting devices, organic-inorganic lead halide perovskites suffer from high content of toxic, polluting, and bioaccumulative Pb, which may eventually hamper their commercialization. Here, we present the synthesis of two-dimensional (2D) Cu-based hybrid perovskites and study their optoelectronic properties to investigate their potential application in solar cells and light-emitting devices, providing a new environmental-friendly alternative to Pb. The series (CH3NH3)2CuClxBr4-x was studied in detail, with the role of Cl found to be essential for stabilization. By exploiting the additional Cu d-d transitions and appropriately tuning the Br/Cl ratio, which affects ligand-to-metal charge transfer transitions, the optical absorption in this series of compounds can be extended to the near-infrared for optimal spectral overlap with the solar irradiance. In situ formation of Cu(+) ions was found to be responsible for the green photoluminescence of this material set. Processing conditions for integrating Cu-based perovskites into photovoltaic device architectures, as well as the factors currently limiting photovoltaic performance, are discussed: among them, we identified the combination of low absorption coefficient and heavy mass of the holes as main limitations for the solar cell efficiency. To the best of our knowledge, this is the first demonstration of the potential of 2D copper perovskite as light harvesters and lays the foundation for further development of perovskite based on transition metals as alternative lead-free materials. Appropriate molecular design will be necessary to improve the material's properties and solar cell performance filling the gap with the state-of-the-art Pb-based perovskite devices. PMID:26756860

  3. Flexible and transparent nanogenerators based on a composite of lead-free ZnSnO3 triangular-belts.

    PubMed

    Wu, Jyh Ming; Xu, Chen; Zhang, Yan; Yang, Ya; Zhou, Yusheng; Wang, Zhong Lin

    2012-11-27

    A flexible and transparent lead-free triangular-belt ZnSnO(3) nanogenerator is demonstrated. When a mechanical deformation of ≈0.1% is applied to the triangular-belt ZnSnO(3) nanogenerator, the output voltage and current reached 5.3 V and 0.13 μA, respectively, which indicated a maximum output power density of ≈11 μW·cm(-3). This is the highest output power that has been demonstrated by lead-free ZnSnO(3) triangular-belts. PMID:22941870

  4. Consideration of impedance matching techniques for efficient piezoelectric energy harvesting.

    PubMed

    Kim, Hyeoungwoo; Priya, Shashank; Stephanou, Harry; Uchino, Kenji

    2007-09-01

    This study investigates multiple levels of impedance-matching methods for piezoelectric energy harvesting in order to enhance the conversion of mechanical to electrical energy. First, the transduction rate was improved by using a high piezoelectric voltage constant (g) ceramic material having a magnitude of g33 = 40 x 10(-3) V m/N. Second, a transducer structure, cymbal, was optimized and fabricated to match the mechanical impedance of vibration source to that of the piezoelectric transducer. The cymbal transducer was found to exhibit approximately 40 times higher effective strain coefficient than the piezoelectric ceramics. Third, the electrical impedance matching for the energy harvesting circuit was considered to allow the transfer of generated power to a storage media. It was found that, by using the 10-layer ceramics instead of the single layer, the output current can be increased by 10 times, and the output load can be reduced by 40 times. Furthermore, by using the multilayer ceramics the output power was found to increase by 100%. A direct current (DC)-DC buck converter was fabricated to transfer the accumulated electrical energy in a capacitor to a lower output load. The converter was optimized such that it required less than 5 mW for operation. PMID:17941391

  5. Temperature dependence of the intrinsic and extrinsic contributions in BiFeO3-(K0.5Bi0.5)TiO3-PbTiO3 piezoelectric ceramics

    NASA Astrophysics Data System (ADS)

    Bennett, J.; Shrout, T. R.; Zhang, S. J.; Mandal, P.; Bell, A. J.; Stevenson, T. J.; Comyn, T. P.

    2014-09-01

    This contribution focuses on the use of modified Rayleigh law as a technique for determining the intrinsic and extrinsic (reversible/irreversible) contributions to the piezoelectric effect up to 150 C across a broad compositional space, augmenting previous understanding of the BiFeO3-(K0.5Bi0.5)TiO3-PbTiO3 system. At room temperature, a mechanistic explanation of the correlation between crystal symmetry, i.e., tetragonal spontaneous strain, xs, and the Rayleigh relations using Landau theory is provided. The intrinsic response was found to be heavily dependent upon the tetragonal xs, whereby an optimisation between polarization and permittivity was elucidated, leading to enhanced piezoelectric charge coefficients. A c/a ratio of 1.041 was identified at which the room temperature intrinsic and extrinsic effects were at a maximum; a dinit of 183 10-12 m/V and Rayleigh coefficient of 59 10-18 m2/V2 were measured, resulting in the largest piezoelectric charge coefficients. The piezoelectric charge coefficient d33, intrinsic and extrinsic contributions of these materials were all found to increase up to 150 C while adhering to the Rayleigh model. The reversible extrinsic component of the total reversible response, dinit, was calculated to be relatively minor, 4.9% at room temperature, increasing to 12.1% at 150 C, signifying its increasing influence to the piezoelectric effect, as domain wall motion is thermally activated. Hence, the phenomenological interpretation provided here may be used as a roadmap to elucidate the origins of the temperature dependence of the piezoelectric effect.

  6. Resonance enhancement of piezoelectric, dielectric, and magnetoelectric characteristics of inhomogeneous multiferroics in alternating electric field

    NASA Astrophysics Data System (ADS)

    Radchenko, G. S.

    2008-11-01

    A resonance piezoelectric effect in a multilayer ceramic composite has been studied. Expressions for the effective dielectric permittivity and piezoelectric coefficient of the layered composite are obtained. It is shown that, in the vicinity of the piezoelectric resonance frequency, the effective response of the composite to an external action can be significantly enhanced. The behavior of the ferromagnet-piezoelectric composite is described with allowance for spatial oscillations of the electric and magnetic field. Transversal piezomodulus, magnetoelectric susceptibility, and dielectric permittivity of layered multiferroics are considered.

  7. A high-temperature double-mode piezoelectric ultrasonic linear motor

    NASA Astrophysics Data System (ADS)

    Li, Xiaotian; Chen, Jianguo; Chen, Zhijiang; Dong, Shuxiang

    2012-08-01

    A miniature piezoelectric ultrasonic linear motor (piezoelectric vibrator sizes: 4.7 13.5 2 mm3) has been studied for precise actuation at 200 C high-temperature. This piezoelectric linear motor was made of (1-x)BiScO3-xPbTiO3 piezoelectric ceramic with a high curie temperature (428 C) and it was operated in first longitudinal and the second bending double-mode. Our experimental results showed that the linear motor moves smoothly at the temperature as high as 200 C with a driving force of 0.35 N and a speed up to 42 mm/s.

  8. Dual strain mechanisms in a lead-free morphotropic phase boundary ferroelectric

    NASA Astrophysics Data System (ADS)

    Walker, Julian; Simons, Hugh; Alikin, Denis O.; Turygin, Anton P.; Shur, Vladimir Y.; Kholkin, Andrei L.; Ursic, Hana; Bencan, Andreja; Malic, Barbara; Nagarajan, Valanoor; Rojac, Tadej

    2016-01-01

    Electromechanical properties such as d33 and strain are significantly enhanced at morphotropic phase boundaries (MPBs) between two or more different crystal structures. Many actuators, sensors and MEMS devices are therefore systems with MPBs, usually between polar phases in lead (Pb)-based ferroelectric ceramics. In the search for Pb-free alternatives, systems with MPBs between polar and non-polar phases have recently been theorized as having great promise. While such an MPB was identified in rare-earth (RE) modified bismuth ferrite (BFO) thin films, synthesis challenges have prevented its realization in ceramics. Overcoming these, we demonstrate a comparable electromechanical response to Pb-based materials at the polar-to-non-polar MPB in Sm modified BFO. This arises from ‘dual’ strain mechanisms: ferroelectric/ferroelastic switching and a previously unreported electric-field induced transition of an anti-polar intermediate phase. We show that intermediate phases play an important role in the macroscopic strain response, and may have potential to enhance electromechanical properties at polar-to-non-polar MPBs.

  9. Dual strain mechanisms in a lead-free morphotropic phase boundary ferroelectric.

    PubMed

    Walker, Julian; Simons, Hugh; Alikin, Denis O; Turygin, Anton P; Shur, Vladimir Y; Kholkin, Andrei L; Ursic, Hana; Bencan, Andreja; Malic, Barbara; Nagarajan, Valanoor; Rojac, Tadej

    2016-01-01

    Electromechanical properties such as d33 and strain are significantly enhanced at morphotropic phase boundaries (MPBs) between two or more different crystal structures. Many actuators, sensors and MEMS devices are therefore systems with MPBs, usually between polar phases in lead (Pb)-based ferroelectric ceramics. In the search for Pb-free alternatives, systems with MPBs between polar and non-polar phases have recently been theorized as having great promise. While such an MPB was identified in rare-earth (RE) modified bismuth ferrite (BFO) thin films, synthesis challenges have prevented its realization in ceramics. Overcoming these, we demonstrate a comparable electromechanical response to Pb-based materials at the polar-to-non-polar MPB in Sm modified BFO. This arises from 'dual' strain mechanisms: ferroelectric/ferroelastic switching and a previously unreported electric-field induced transition of an anti-polar intermediate phase. We show that intermediate phases play an important role in the macroscopic strain response, and may have potential to enhance electromechanical properties at polar-to-non-polar MPBs. PMID:26791098

  10. Dual strain mechanisms in a lead-free morphotropic phase boundary ferroelectric

    PubMed Central

    Walker, Julian; Simons, Hugh; Alikin, Denis O.; Turygin, Anton P.; Shur, Vladimir Y.; Kholkin, Andrei L.; Ursic, Hana; Bencan, Andreja; Malic, Barbara; Nagarajan, Valanoor; Rojac, Tadej

    2016-01-01

    Electromechanical properties such as d33 and strain are significantly enhanced at morphotropic phase boundaries (MPBs) between two or more different crystal structures. Many actuators, sensors and MEMS devices are therefore systems with MPBs, usually between polar phases in lead (Pb)-based ferroelectric ceramics. In the search for Pb-free alternatives, systems with MPBs between polar and non-polar phases have recently been theorized as having great promise. While such an MPB was identified in rare-earth (RE) modified bismuth ferrite (BFO) thin films, synthesis challenges have prevented its realization in ceramics. Overcoming these, we demonstrate a comparable electromechanical response to Pb-based materials at the polar-to-non-polar MPB in Sm modified BFO. This arises from ‘dual’ strain mechanisms: ferroelectric/ferroelastic switching and a previously unreported electric-field induced transition of an anti-polar intermediate phase. We show that intermediate phases play an important role in the macroscopic strain response, and may have potential to enhance electromechanical properties at polar-to-non-polar MPBs. PMID:26791098

  11. A piezoelectric transformer

    NASA Technical Reports Server (NTRS)

    Won, C. C.

    1993-01-01

    This work describes a modeling and design method whereby a piezoelectric system is formulated by two sets of second-order equations, one for the mechanical system, and the other for the electrical system, coupled through the piezoelectric effect. The solution to this electromechanical coupled system gives a physical interpretation of the piezoelectric effect as a piezoelectric transformer that is a part of the piezoelectric system, which transfers the applied mechanical force into a force-controlled current source, and short circuit mechanical compliance into capacitance. It also transfers the voltage source into a voltage-controlled relative velocity input, and free motional capacitance into mechanical compliance. The formulation and interpretation simplify the modeling of smart structures and lead to physical insight that aids the designer. Due to its physical realization, the smart structural system can be unconditional stable and effectively control responses. This new concept has been demonstrated in three numerical examples for a simple piezoelectric system.

  12. Study of piezoelectric transducers in smart structure applications

    NASA Astrophysics Data System (ADS)

    Lam, Kwok Ho

    To develop a novel smart material in civil engineering applications, cement-based 1-3 composites have been fabricated and characterized. The feasibility of the embedded 1-3 composite transducers in structural monitoring applications have been demonstrated in this project. In the present work, piezoelectric ceramic discs and fibres were fabricated and used as the active phases of the 1-3 composites. Lead zirconate titanate (PZT) ceramic discs were fabricated using a conventional dry pressing method. All the parameters of PZT ceramics have been evaluated by a resonance technique. Crack-free PZT ceramic fibres were fabricated using a simple powder mixing method. The microstructural and electrical characterizations show that performance of the ceramic fibres can be comparable to that of the corresponding bulk ceramics. To study the piezoceramic/cement 1-3 composites, the properties of cement have been studied as a function of water content. The elastic properties of cement with different water/cement ratios were characterized using the ultrasonic immersion method. It was found that the cement paste with water/cement ratio of 0.5 is relatively "soft" to be used as the passive phase of a 1-3 composite. When comparing with the ceramics, the acoustic impedance of cement is much closer to that of concrete. Piezoelectric PZT/cement 1-3 composites with a wide range of the ceramic volume fraction (?= 0.25--0.77) have been fabricated successfully using a dice-and-fill technique. Piezoelectric properties of the 1-3 composites were determined by a resonance technique. The characterization showed that the high piezoelectric characteristics of ceramics were maintained and the effective acoustic impedance of composites was reduced as expected. Even the phase matrix is the cement paste, the thickness electromechanical coupling coefficient kt of the 1-3 composites can be enhanced effectively which approaches to the k33 coefficient of the ceramics. The 1-3 composites were found to have reasonable piezoelectric properties that agree quite well with a theoretical modelling. (Abstract shortened by UMI.)

  13. Design, Manufacturing and Characterization of Functionally Graded Flextensional Piezoelectric Actuators

    NASA Astrophysics Data System (ADS)

    Amigo, R. C. R.; Vatanabe, S. L.; Silva, E. C. N.

    2013-03-01

    Previous works have been shown several advantages in using Functionally Graded Materials (FGMs) for the performance of flextensional devices, such as reduction of stress concentrations and gains in reliability. In this work, the FGM concept is explored in the design of graded devices by using the Topology Optimization Method (TOM), in order to determine optimal topologies and gradations of the coupled structures of piezoactuators. The graded pieces are manufactured by using the Spark Plasma Sintering (SPS) technique and are bonded to piezoelectric ceramics. The graded actuators are then tested by using a modular vibrometer system for measuring output displacements, in order to validate the numerical simulations. The technological path developed here represents the initial step toward the manufacturing of an integral piezoelectric device, constituted by piezoelectric and non-piezoelectric materials without bonding layers.

  14. Shielding properties of lead-free protective clothing and their impact on radiation doses

    SciTech Connect

    Schlattl, Helmut; Zankl, Maria; Eder, Heinrich; Hoeschen, Christoph

    2007-11-15

    The shielding properties of two different lead-free materials--tin and a compound of 80% tin and 20% bismuth--for protective clothing are compared with those of lead for three typical x-ray spectra generated at tube voltages of 60, 75, and 120 kV. Three different quantities were used to compare the shielding capability of the different materials: (1) Air-kerma attenuation factors in narrow-beam geometry, (2) air-kerma attenuation factors in broad-beam geometry, and (3) ratios of organ and effective doses in the human body for a whole-body irradiation with a parallel beam directed frontally at the body. The thicknesses of tin (0.45 mm) and the tin/bismuth compound (0.41 mm) to be compared against lead correspond to a lead equivalence value of 0.35 mm for the 75 kV spectrum. The narrow-beam attenuation factors for 0.45 mm tin are 54% and 32% lower than those for 0.35 mm lead for 60 and 120 kV; those for 0.41 mm tin/bismuth are 12% and 32% lower, respectively. The decrease of the broad-beam air-kerma attenuation factors compared to lead is 74%, 46%, and 41% for tin and 42%, 26%, and 33% for tin/bismuth and the spectra at 60, 75, and 120 kV, respectively. Therefore, it is recommended that the characterization of the shielding potential of a material should be done by measurements in broad-beam geometry. Since the secondary radiation that is mainly responsible for the shielding reduction in broad-beam geometry is of low penetrability, only more superficially located organs receive significantly enhanced doses. The increase for the dose to the glandular breast tissue (female) compared to being shielded by lead is 143%, 37%, and 45% when shielded by tin, and 35%, 15%, and 39% when shielded by tin/bismuth for 60, 75, and 120 kV, respectively. The effective dose rises by 60%, 6%, and 38% for tin, and 14%, 3% and, 35% for tin/bismuth shielding, respectively.

  15. SU-E-P-09: Radiation Transmission Measurements and Evaluation of Diagnostic Lead-Based and Lead-Free Aprons

    SciTech Connect

    Syh, J

    2014-06-01

    Purpose: This study was conducted to ensure that various lead shield apron manufacturers provided accurate attenuation factors regardless of whether the apron was made of lead-based or lead-free equivalent material. Methods: A calibrated ionization survey meter was placed at chest height and 36 cm horizontally away from a solid water phantom on a simulator couch. Measurements were done with or without apron. Radiation field was set to 24cmx24cm with the phantom at 100cm source-to-surface distance. Irradiation time was set for 1 minute at voltages of 60, 80, 100 and 120 kVp. Current was set at 6mA. Results: Between 60 kVp and 120 kVp, the transmission through 0.50 mm of lead-based apron was between 1.0% and 6.5% with a mean value of 3.2% and a standard deviation (s.d.) of 1.4%. The transmissions through the 0.50 mm lead-free aprons were 1.0 % to 12.0% with a mean value of 6.1% and s.d. of 2.6%. At 120 kVp, the transmission value was 6.5% for 0.50 mm lead-based apron and 11.1% to 12.0% for 0.50 mm lead-free aprons. The radiation transmissions at 80 kVp, measured in two different 0.5 mm lead-free aprons, were 4.3% each. However, only 1.4% transmission was found through the lead-based apron. Overall, the radiation transmitted through the lead-based apron was 1/3 transmission of lead-free at 80kVp, and half value of lead-free aprons at 100 and 120 kVp. Conclusion: Even though lead-based and lead-free aprons all claimed to have the same lead equivalent thickness, the transmission might not be the same. The precaution was needed to exercise diligence in quality assurance program to assure adequate protection to staff who wear it during diagnostic procedures. The requirement for aprons not only should be in certain thickness to meet state regulation but also to keep reasonably achievable low exposure with the accurate labeling from manufacturers.

  16. Pulsed laser deposition of lead-free (Na0.5Bi0.5)1-xBaxTiO3 ferroelectric thin films with enhanced dielectric properties

    NASA Astrophysics Data System (ADS)

    Andrei, A.; Scarisoreanu, N. D.; Birjega, R.; Dinescu, M.; Stanciu, G.; Craciun, F.; Galassi, C.

    2013-08-01

    Ferroelectric lead-free (Na0.5Bi0.5)1-xBaxTiO3 thin films obtained by pulsed laser deposition have been structurally and electrically investigated for compositions, x = 0 and x = 0.06, in and out of the morphotropic phase boundary (MPB). Sodium bismuth titanate Na0.5Bi0.5TiO3 (NBT), pure or in solid solution with other materials (like BaTiO3), is considered to be the best candidate material for lead-free ferroelectric and piezoelectric applications such as actuators and nonvolatile memory devices. Bulk solid solutions with BaTiO3 (BT), (1-x)NBT-xBT (NBT-x%BT) have been investigated widely, also due to a morphotropic phase boundary (MPB) with enhanced dielectric and ferroelectric properties between a rhombohedral and a tetragonal ferroelectric phase, at x = 0.06. Nonetheless, to transpose bulk properties to NBT-BT thin films is a major achievement. XRD technique has been used for structural characterizations of NBT-BT films. Dielectric spectroscopy measurements were performed at room temperature in the frequency range 100 Hz-1 MHz. The best films show pure perovskite phase and good crystalline structure, as a function of specific deposition conditions. Unusual characteristics, especially dielectric constant values higher than those for bulk, have been found for films with specific crystallographic orientations.

  17. Nonlinear dielectric response in piezoelectric materials for underwater transducers

    NASA Astrophysics Data System (ADS)

    Sherlock, N. P.; Garten, L. M.; Zhang, S. J.; Shrout, T. R.; Meyer, R. J.

    2012-12-01

    SONAR transducers based on single crystal lead magnesium niobate-lead titanate (PMNT) have demonstrated improvements over conventional lead zirconate titanate ceramics. Compositional modifications to PMNT have combined the high piezoelectric coefficient (d33 > 2000 pC/N) and electromechanical coupling factor (k33 > 0.90) with the low mechanical losses (QM > 1000) of "hard" piezoelectric ceramics. The dielectric losses of single crystal PMNT have not been investigated as extensively as the mechanical losses but may significantly affect the performance of a device when water loaded. In this work, nonlinearities in the dielectric permittivity and losses have been investigated as a function of applied electric field, measurement frequency, and temperature. It is shown that electromechanically "hard" single crystals offer greater stability of the dielectric properties while maintaining a high permittivity with respect to conventional lead zirconate titanate ceramics.

  18. Design and analysis of a piezoelectric material based touch screen with additional pressure and its acceleration measurement functions

    NASA Astrophysics Data System (ADS)

    Chu, Xiang-Cheng; Liu, Jia-Yi; Gao, Ren-Long; Chang, Jie; Li, Long-Tu

    2013-12-01

    Touch screens are becoming more and more prevalent in everyday environments due to their convenience and humanized operation. In this paper, a piezoelectric material based touch screen is developed and investigated. Piezoelectric ceramics arrayed under the touch panel at the edges or corners are used as tactile sensors to measure the touch positioning point similarly to conventional touch screens. However, additional touch pressure and its acceleration performance can also be obtained to obtain a higher-level human-machine interface. The piezoelectric ceramics can also be added to a traditional touch screen structure, or they can be used independently to construct a novel touch screen with a high light transmittance approach to a transparent glass. The piezoelectric ceramics were processed from PZT piezoelectric ceramic powder into a round or rectangular shape. According to the varied touch position and physical press strength of a finger, or even a gloved hand or fingernail, the piezoelectric tactile sensors will have different output voltage responses. By calculating the ratio of different piezoelectric tactile sensors responses and summing up all piezoelectric tactile sensors output voltages, the touch point position, touch pressure and touch force acceleration can be detected. A prototype of such a touch screen is manufactured and its position accuracy, touch pressure and response speed are measured in detail. The experimental results show that the prototype has many advantages such as high light transmittance, low energy cost and high durability.

  19. Wave propagation in a piezoelectric layer

    SciTech Connect

    Ramos, R.R.; Otero, J.A.

    1997-06-01

    The dispersion relations of oscillation modes in a piezoelectric slab with hexagonal symmetry are given, considering the slab infinite with respect to the axes x{sub 1} and x{sub 2} with the six-order symmetry axis perpendicular to the x{sub 1}{endash}x{sub 2} plane. Four types of modes are identified: two of them are transversal horizontal and the other two are associated to electrostatic potential waves which determine the longitudinal and flexural modes. The secular equations for these modes are given and numerical results for the piezoelectric transducer ceramic slab are obtained and compared to experimental results with a very good agreement. {copyright} {ital 1997 American Institute of Physics.}

  20. NASA-DoD Lead-Free Electronics Project. DRAFT Joint Test Report

    NASA Technical Reports Server (NTRS)

    Kessel, Kurt

    2011-01-01

    The use of conventional tin-lead (SnPb) in circuit board manufacturing is under ever-increasing political scrutiny due to increasing regulations concerning lead. The "Restriction of Hazardous Substances" (RoHS) directive enacted by the European Union (EU) and a pact between the United States National Electronics Manufacturing Initiative (NEMI), Europe's Soldertec at Tin Technology Ltd. and the Japan Electronics and Information Technology Industries Association (JEITA) are just two examples where worldwide legislative actions and partnerships/agreements are affecting the electronics industry. As a result, many global commercial-grade electronic component suppliers are initiating efforts to transition to lead-free (Pb-free) in order to retain their worldwide market. Pb-free components are likely to find their way into the inventory of aerospace or military assembly processes under current government acquisition reform initiatives. Inventories "contaminated" by Pb-free will result in increased risks associated with the manufacturing, product reliability, and subsequent repair of aerospace and military electronic systems. Although electronics for military and aerospace applications are not included in the RoHS legislation, engineers are beginning to find that the commercial industry's move towards RoHS compliance has affected their supply chain and changed their parts. Most parts suppliers plan to phase out their non-compliant, leaded production and many have already done so. As a result, the ability to find leaded components is getting harder and harder. Some buyers are now attempting to acquire the remaining SnPb inventory, if it's not already obsolete. Original Equipment Manufacturers (OEMs), depots, and support contractors have to be prepared to deal with an electronics supply chain that increasingly provides more and more parts with Pb-free finishes-some labeled no differently than their Pb counterparts-while at the same time providing the traditional Pb parts. The longer the transition period, the greater the likelihood of Pb-free parts inadvertently being mixed with Pb parts and ending up on what are supposed to be Pb systems. As a result, OEMs, depots, and support contractors need to take action now to either abate the influx of Pb-free parts, or accept it and deal with the likely interim consequences of reduced reliability due to a wide variety of matters, such as Pb contamination, high temperature incompatibility, and tin whiskering. Allowance of Pb-free components produces one of the greatest risks to the reliability of a weapon system. This is due to new and poorly understood failure mechanisms, as well as unknown long-term reliability. If the decision is made to consciously allow Pb-free solder and component finishes into SnPb electronics, additional effort (and cost) will be required to make the significant number of changes to drawings and task order procedures. This project is a follow-on effort to the Joint Council on Aging Aircraft/Joint Group on Pollution Prevention (JCAA/JG-PP) Pb-free Solder Project which was the first group to test the reliability of Pb-free solder joints against the requirements of the aerospace and military community.