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Sample records for lead-free piezoelectric ceramics

  1. Characterization of Hard Piezoelectric Lead-Free Ceramics

    PubMed Central

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

    2010-01-01

    K4CuNb8O23 doped K0.45Na0.55NbO3 (KNN-KCN) ferroelectric ceramics were found to exhibit asymmetrical polarization hysteresis loops, related to the development of an internal bias field. The internal bias field is believed to be the result of defect dipoles of acceptor ions and oxygen vacancies, which lead to piezoelectric hardening effect, by stabilizing and pinning of the domain wall motion. The dielectric loss for the hard lead-free piezoelectric ceramic was found to be 0.6%, with mechanical quality factors Q on the order of >1500. Furthermore, the piezoelectric properties were found to decrease and the coercive field increased, when compared with the undoped material, exhibiting a typical characteristic of hard behavior. The temperature usage range was limited by the polymorphic phase transition temperature, being 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. KNNNTK 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)NbO?-based lead-free piezoelectric ceramic was successfully densified. It exhibited an enhanced electromechanical coupling factor of k?=0.52, a piezoelectric constant d??=252 pC/N, and a frequency constant N?=3170 Hz m because of the incorporation of an elaborate secondary phase composed primarily of KTiNbO?. The ceramic's nominal composition was 0.92K?.??Na?.??Ca?.??Li?.??Nb?.??O?0.047K?.??Ti?.??Nb?.??O?0.023BaZrO? 0.0017Co?O?0.002Fe?O?0.005ZnO, abbreviated herein as KNNNTK composite. The KNNNTK 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 (TEMEDS) 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 K?(Ti,Nb,Co,Zn)?O?? or CoZnTiO? 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 KNNNTK 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 KNNNTK composite ceramic's piezoelectric characteristics.

  3. 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.

  4. Lead-free piezoelectric ceramics and thin films.

    PubMed

    Safari, Ahmad; Abazari, Maryam

    2010-10-01

    Recent progress in lead-free piezoelectric ceramics and thin films with special emphasis on alkaline niobatebased and bismuth sodium titanate-based systems is reviewed concisely. Modifications of potassium sodium niobate (KNN) ceramics are presented and subsequent improvements in the electrical properties are summarized. Special attention is devoted to the phase diagram of the KNN system when a solid solution is formed with other perovskite niobates and titanates. Impact of A-site and B-site dopants on the electromechanical properties of KNN ceramics are distinguished in view of transition temperatures. It is shown that the addition of most A-site and B-site dopants reduces the transition temperatures and improves the piezoactivity at room temperature. This is attributed to the shift of polymorphic transition from tetragonal to orthorhombic phase in the vicinity of room temperature. In contrast, formation of a solid solution of KNN with 18 mol% AgNbO? revealed a significant enhancement of properties without a notable change in the transition temperatures. Also, a bismuth sodium titanate (BNT) composition is introduced with particular emphasis on its binary and ternary derivatives. Moderate piezoelectric properties reported at the morphotropic phase boundaries, formed in BNT-based solid solutions are also represented. Advances on thin films based on these two compositions are evaluated and challenges involved with development of stoichiometric thin films with low leakage current are discussed. PMID:20889401

  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 Central

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

    2010-01-01

    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 (K0.5Na0.5)0.97Li0.03(Nb0.9 Ta0.1)O3 (abbreviated as KNLNT-0.03/0.10) was fabricated and characterized. The material was found to have a clamped dielectric constant ?33S = ?0 = 890, piezoelectric coefficient d33 = 245 pC/N, electromechanical coupling factor kt = 0.42 and Curie temperature Tc > 300 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. 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.

  8. 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.

  9. 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.

  10. Novel lead-free piezoelectric ceramics in the solid solution (1-x) bismuth iron oxide-barium titanate

    NASA Astrophysics Data System (ADS)

    Leontsev, Serhiy

    Piezoelectric materials are widely used in many areas of science and technology due to their electromechanical properties. The transformation of mechanical energy into electrical signals and vice versa based on the piezoelectric effect has led to the development of sensor devices and piezoelectric actuators used in accelerometers, pressure and vibration meters, micropositioning devices, ultrasound generators, motors etc. The most technologically important piezoelectric material is lead zirconate titanate PbZrO3-PbTiO3 (PZT), however, the commercial manufacture and application of PZT as a lead-based material represent serious health hazards. The need to reduce environmental contamination by lead-based substances has created the current drive to develop alternative lead-free piezoelectric materials. The present work describes a detailed investigation of the novel multifunctional ceramic material in a solid solution of bismuth iron oxide and barium titanate (1-x)BiFeO 3-xBaTiO3 (BFBT) with an emphasis on the room temperature piezoelectric properties and structural study. BFBT ceramics were prepared via the metal oxide solid-state preparation route. Addition of manganese oxide MnO2 increased the DC resistance by one to five orders of magnitude allowing high-field poling and piezoelectric strain measurements in Mn-modified BFBT ceramics. Piezoelectric d33 coefficients of 116 pC/N (low-field, Berlincourt) and 326 pC/N (effective, high-field) are reported for the compositions with x=0.25 and 0.33 respectively. Piezoelectric measurements using the Rayleigh law under applied large DC electric field indicated an increased low-field piezoelectric d33 coefficient to 150 pC/N (x=0.33). The DC bias is believed to stabilize the ferroclectric domain structure leading to stronger intrinsic and extrinsic contributions to the piezoelectric response in BFBT. Bright field TEM imaging confirmed formation of macroscopic domains following high field poling from initially frustrated domain state indicating the ability to induce long-range polarization order in BFBT ceramics. It is believed that the results of this work will contribute to the development of a family of lead-free piezoelectric materials based on BiFeO3-BaTiO3 system. KEYWORDS: Bismuth ferrite, Barium titanate, Lead-free, Piezoelectric ceramics, Crystal Structure

  11. 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

  12. Preparation and Characterization of Lead-free Piezoelectric Ceramics Qiang Chen1,a

    E-print Network

    Volinsky, Alex A.

    -pressing technique as well as spark plasma sintering have been used to obtain high densities [2], but such processing a chenqiang30sf@163.com, b jxli65@ustb.edu.cn (corresponding author) Keywords: Sintering; Piezoelectric of sintering temperature on the structure, density and electrical properties of KNL-NTS ceramics were

  13. Enhanced Piezoelectric Properties and Tunability of Lead-Free Ceramics Prepared by High-Energy Ball Milling

    NASA Astrophysics Data System (ADS)

    Mahesh, M. L. V.; Bhanuprasad, V. V.; James, A. R.

    2013-12-01

    Zirconium-doped barium titanate Ba(Zr0.15Ti0.85)O3 lead-free ceramics (hereinafter referred to as BZT) were synthesized using the solid-state reaction method by adopting the high-energy ball milling technique. Nanosized BZT powders resulted from high-energy ball milling, which in turn enhanced the dielectric and piezoelectric properties of the ceramics. A single-phase perovskite structure free from secondary phase peaks was observed for sintered BZT samples, and a relative density of 94% of the theoretical density was achieved. The electric-field-induced polarization-current data indicate the ferroelectric nature of the samples. Unipolar strain as high as 0.12% was realized for the ceramics sintered at 1350C, indicating their potential for use in actuator applications. Very high tunability of >70% for these ceramics is also reported.

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

    PubMed

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

    2015-08-14

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

  15. 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.

  16. 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.

  17. Dielectric and piezoelectric properties of sodium lithium niobate Na1-xLixNbO3 lead free ferroelectric ceramics

    E-print Network

    Cao, Wenwu

    by the high temperature shrinkage instrument. Structural phases were characterized by X-ray diffraction using Electric TH2817). Piezoelectric constant d33 was measured by a quasi-static d # Springer Science + Business Media, LLC 2007 Abstract High density sodium lithium niobate lead free ce

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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 (25100 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.

  3. 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, ?-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 1075C 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.

  4. 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.

  5. Fabrication and Characterization of (100),(001)-Oriented Reduction-Resistant Lead-Free Piezoelectric (Ba,Ca)TiO3 Ceramics Using Platelike Seed Crystals

    NASA Astrophysics Data System (ADS)

    Ichikawa, Hiroki; Sakamoto, Wataru; Akiyama, Yoshikazu; Maiwa, Hiroshi; Moriya, Makoto; Yogo, Toshinobu

    2013-09-01

    The preparation of reduction-resistant (Ba,Ca)TiO3 ceramics as lead-free piezoelectric materials was studied. To improve their electrical properties, (100),(001)-oriented (Ba0.85Ca0.15)TiO3 ceramics were fabricated by the reactive templated grain growth method using a mixture of platelike CaTiO3 and BaTiO3 particles. The platelike CaTiO3 and BaTiO3 particles were prepared through a topochemical microcrystal conversion process using CaBi4Ti4O15 and BaBi4Ti4O15 plate-like precursor crystals. The 100 orientation degree of the grain-oriented (Ba0.85Ca0.15)TiO3 ceramics was 92%, as estimated by Lotgering's equation. In addition, 1 mol % Ba excess and 1 mol % Mn-doped (Ba0.85Ca0.15)TiO3 sintered bodies, which were sintered at 1350 C in an Ar flow containing H2 (0.3%), had sufficient resistivity to allow the characterization of electrical properties. The ferroelectric and field-induced strain properties of the (Ba0.85Ca0.15)TiO3 ceramics, sintered in the reducing atmosphere, were markedly improved as a result of fabricating grain-oriented samples. The field-induced strain coefficient (estimated from the slope of the unipolar strain loop) of the nonreducible (100),(001)-oriented (Ba0.85Ca0.15)TiO3 ceramics reached 570 pm/V, which was higher than that of polycrystals (260 pm/V) with no preferential orientation.

  6. Phase transition behavior and high piezoelectric properties in lead-free BaTiO3CaTiO3BaHfO3 ceramics

    E-print Network

    Cao, Wenwu

    piezoelectric coefficient d33 = 410 pC/N, and electrome- chanical coupling factor kp = 0.47, and a relative high composition shows enhanced properties with dielectric constant er = 2889 (at room temperature, 1 kHz), highPhase transition behavior and high piezoelectric properties in lead-free BaTiO3CaTiO3BaHfO3

  7. Lead-free BNBT-6 piezoelectric ceramic fibre/epoxy 1-3 composites for ultrasonic transducer applications

    NASA Astrophysics Data System (ADS)

    Wang, D. Y.; Li, K.; Chan, H. L. W.

    2005-04-01

    Barium-modified bismuth sodium titanate, 0.94 (Bi0.5Na0.5)TiO3-0.06BaTiO3 (BNBT-6), fine-scale piezoelectric fibres were fabricated using a viscous suspension spinning process (VSSP). The sintered BNBT-6 fibres with diameters of 300 ?m were fabricated into 1-3 composites with fibre volume fraction vf of 0.2-0.5. Piezoelectric and dielectric properties of the 1-3 composites were measured. The electromechanical coupling coefficient kt of a vf=0.40 composite is 0.52. Properties of the VSSP fibres were calculated using the measured properties of the 1-3 composites. A vf=0.40 composite was thinned down to 213-?m thickness and constructed into an ultrasonic transducer. The pulse-echo response, bandwidth and insertion loss of the transducers were studied. The VSSP fibre composite transducer with vf=0.40 has a centre frequency of 7 MHz with a bandwidth of 88%. The good performance indicated that the BNBT-6/epoxy 1-3 fibre composite transducer has potential for medical imaging applications.

  8. 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.

  9. 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.

  10. 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 ? of 1.27-1.40 ms and a large quantum yield ? 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.

  11. 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.

  12. 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.

  13. 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

  14. 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.

  15. 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.

  16. 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.

  17. 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

  18. 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.

  19. 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

  20. 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.

  1. 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.

  2. Effect of composition on electrical properties of lead-free Bi0.5(Na0.80K0.20)0.5TiO3-(Ba0.98Nd0.02)TiO3 piezoelectric ceramics

    NASA Astrophysics Data System (ADS)

    Jaita, Pharatree; Watcharapasorn, Anucha; Jiansirisomboon, Sukanda

    2013-07-01

    Lead-free piezoelectric ceramics with the composition of (1-x)Bi0.5(Na0.80K0.20)0.5TiO3-x(Ba0.98Nd0.02)TiO3 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 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 (?r = 1716, tan? = 0.0701, Tc = 327 C, and d33 = 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. 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.

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

    PubMed

    Rubio-Marcos, Fernando; Lpez-Jurez, Rigoberto; Rojas-Hernandez, Rocio E; Del Campo, Adolfo; Razo-Prez, Neftal; 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

  5. 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.

  6. Effects of K content on the dielectric, piezoelectric, and ferroelectric properties of 0.95(K{sub x}Na{sub 1-x})NbO{sub 3}-0.05LiSbO{sub 3} lead-free ceramics

    SciTech Connect

    Wu Jiagang; Xiao Dingquan; Zhu Jianguo; Yu Ping; Wang Yuanyu

    2008-01-15

    The effects of K content on the dielectric, piezoelectric, and ferroelectric properties of 0.95(K{sub x}Na{sub 1-x})NbO{sub 3}-0.05LiSbO{sub 3} (0.95K{sub x}NN-0.05LS) (x=0.25-0.75) lead-free piezoelectric ceramics prepared by conventional solid-state sintering were studied. The experimental results show that the dielectric, piezoelectric, and ferroelectric properties strongly depend on K content in the 0.95K{sub x}NN-0.05LS ceramics. The 0.95K{sub x}NN-0.05LS (x=0.40) ceramics exhibit enhanced electrical properties (d{sub 33}{approx_equal}280 pC/N; k{sub p}{approx_equal}49.4%; T{sub c}{approx}364 deg. C; T{sub o-t}=25 deg. C; {epsilon}{sub r}{approx_equal}1463; tan {delta}{approx_equal}2.3%; P{sub r}{approx}30.8 {mu}C/cm{sup 2}; E{sub c}{approx}14.0 kV/cm). The enhanced electrical properties of 0.95K{sub x}NN-0.05LS (x=0.40) ceramics are attributed to the polymorphic phase transition near room temperature. These results show that 0.95K{sub x}NN-0.05LS (x=0.40) ceramic is a promising lead-free piezoelectric material.

  7. Dielectric and piezoelectric properties of Y{sub 2}O{sub 3} doped (Bi{sub 0.5}Na{sub 0.5}){sub 0.94}Ba{sub 0.06}TiO{sub 3} lead-free piezoelectric ceramics

    SciTech Connect

    Zhou Changrong Liu Xinyu; Li Weizhou; Yuan Changlai

    2009-04-02

    Y{sub 2}O{sub 3} doped lead-free piezoelectric ceramics (Bi{sub 0.5}Na{sub 0.5}){sub 0.94}Ba{sub 0.06}TiO{sub 3} (0-0.7 wt%) were synthesized by the conventional solid state reaction method, and the effect of Y{sub 2}O{sub 3} addition on the structure and electrical properties was investigated. X-ray diffraction shows that Y{sub 2}O{sub 3} diffuses into the lattice of (Bi{sub 0.5}Na{sub 0.5}){sub 0.94}Ba{sub 0.06}TiO{sub 3} to form a solid solution with a pure perovskite structure. The temperature dependence of dielectric constant of Y{sub 2}O{sub 3} doped samples under various frequencies indicates obvious relaxor characteristics different from typical relaxor ferroelectric and the mechanism of the relaxor behavior was discussed. The optimum piezoelectric properties of piezoelectric constant d{sub 33} = 137 pC/N and the electromechanical coupling factor k{sub p} = 0.30 are obtained at 0.5% and 0.1% Y{sub 2}O{sub 3} addition, respectively.

  8. 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

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

    PubMed

    Aksel, Elena; Jones, Jacob L

    2010-01-01

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

  11. 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

  12. 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

  13. 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.

  14. 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?m 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

  15. Nanoscale oxygen octahedral tilting in 0.90(Bi{sub 1/2}Na{sub 1/2})TiO{sub 3}-0.05(Bi{sub 1/2}K{sub 1/2})TiO{sub 3}-0.05BaTiO{sub 3} lead-free perovskite piezoelectric ceramics

    SciTech Connect

    Tai, Cheuk W.; Lereah, Y.

    2009-08-10

    The oxygen octahedral tilted domains in 0.90(Bi{sub 1/2}Na{sub 1/2})TiO{sub 3}-0.5(Bi{sub 1/2}K{sub 1/2})TiO{sub 3}-0.5BaTiO{sub 3} lead-free perovskite piezoelectric ceramic have been studied by transmission electron microscopy (TEM). Selected-area electron diffraction patterns shows the (1/2)ooo and (1/2)ooe reflections, indicating the presence of antiphase (a{sup -}a{sup -}a{sup -}) and in-phase (a{sup o}a{sup o}c{sup +}) octahedral tilting, respectively. The morphology and distributions of these tilted domains are shown in the centered dark-field images. Further, the Bragg-filtered high-resolution TEM image reveals that the size of the in-phase tilted domains varies from 1 to 8 nm across. The ceramic contains the mixture of nontilted and variants of the antiphase and in-phase tilted domains.

  16. 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.

  17. 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.

  18. 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.

  19. High temperature ultrasonic gas flow sensor based on lead free piezoelectric material

    E-print Network

    Krsmanovic, Dalibor

    2011-11-08

    -based route assisted with inverse microemulsion process to well-dispersed Bi4Ti3O12 nanocrystals. Journal of Nanoparticle Research, 2010. 12(5): J. Hou, Y. Qu, R. Vaish, K.B.R. Varma, D. Krsmanovic, and R.V. Kumar, Crystallographic Evolution, Dielectric... , and Piezoelectric Properties of Bi4Ti3O12:W/Cr Ceramics. Journal of the American Ceramic Society, 2010. 93(5): J. Hou, R. Vaish, Y. Qu, D. Krsmanovic, K.B.R. Varma, and R.V. Kumar, Dielectric, pyroelectric and ferroelectric properties of Bi4Ti2.98Nb0.01Ta0.01O...

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

    NASA Astrophysics Data System (ADS)

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

    2015-07-01

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

  1. 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

  2. Effect of elemental diffusion on temperature coefficient of piezoelectric properties in KNN-based lead-free composites

    E-print Network

    Hong, Soon Hyung

    candidate owing to their excellent piezoelectric properties and high Curie temperature (TC) [114]. HoweverLETTER Effect of elemental diffusion on temperature coefficient of piezoelectric properties in KNN of temperature in KNN- based ceramics. As seen in Fig. 1a, high temperature coefficient of piezoelectric

  3. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

  5. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2015-06-01

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

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

    NASA Astrophysics Data System (ADS)

    Bochenek, Dariusz; Niemiec, 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.

  8. Giant strain with ultra-low hysteresis and high temperature stability in grain oriented lead-free K???Bi???TiO?-BaTiO?-Na???Bi???TiO? 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 (K???Bi???TiO?-BaTiO?-xNa???Bi???TiO? (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 (d?? ~ 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.

  9. 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

  10. 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.

  11. Giant strain with ultra-low hysteresis and high temperature stability in grain oriented lead-free K???Bi???TiO?-BaTiO?-Na???Bi???TiO? 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 (K???Bi???TiO?-BaTiO?-xNa???Bi???TiO? (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 (d?? ~ 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 piezoelectricmorematerials.less

  12. 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, Frdric; 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 ?33,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

  13. 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%).

  14. 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

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

    NASA Astrophysics Data System (ADS)

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

    2011-08-01

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

  16. 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 ?m 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.

  17. 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.

  18. Acceleration of osteogenesis by using barium titanate piezoelectric ceramic as an implant material

    NASA Astrophysics Data System (ADS)

    Furuya, K.; Morita, Y.; Tanaka, K.; Katayama, T.; Nakamachi, E.

    2011-04-01

    As bone has piezoelectric properties, it is expected that activity of bone cells and bone formation can be accelerated by applying piezoelectric ceramics to implants. Since lead ions, included in ordinary piezoelectric ceramics, are harmful, a barium titanate (BTO) ceramic, which is a lead-free piezoelectric ceramic, was used in this study. The purpose of this study was to investigate piezoelectric effects of surface charge of BTO on cell differentiation under dynamic loading in vitro. Rat bone marrow cells seeded on surfaces of BTO ceramics were cultured in culture medium supplemented with dexamethasone, ?-glycerophosphate and ascorbic acid while a dynamic load was applied to the BTO ceramics. After 10 days of cultivation, the cell layer and synthesized matrix on the BTO surfaces were scraped off, and then DNA content, alkaline phosphtase (ALP) activity and calcium content were measured, to evaluate osteogenic differentiation. ALP activity on the charged BTO surface was slightly higher than that on the non-charged BTO surface. The amount of calcium on the charged BTO surface was also higher than that on the non-charged BTO surface. These results showed that the electric charged BTO surface accelerated osteogenesis.

  19. 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.

  20. Bi0.5Na0.5TiO3:ZnO lead-free piezoelectric composites with deferred thermal depolarization

    NASA Astrophysics Data System (ADS)

    Zhang, Ji; Pan, Zhao; Nie, Peng-Xiao; Cui, Yu-Shuang; Yang, Bin; Chen, Jun; Zhang, Shan-Tao

    2015-06-01

    Bi0.5Na0.5TiO3 (BNT) is among the most promising lead-free piezoelectric candidates. However, depolarization of BNT is a longstanding obstacle for practical applications. Here, we report that piezoelectric composites of Bi0.5Na0.5TiO3:xZnO (BNT:xZnO, where x is the mole ratio of ZnO to BNT) have deferred thermal depolarization. With increasing x from 0 to 0.4, the observed depolarization temperature (Td) tends to be deferred near x = 0.3, as confirmed by temperature dependent dielectric, ferroelectric, and piezoelectric measurements. As the result, the piezoelectric properties of the composites can be well maintained even after the poled composites are annealed at 125 C. It is proposed that the charges stemming from ZnO can be orderly distributed to form a local field, which can keep the poling state of BNT, thus suppress the depolarization, even after the external poling filed is removed. These results may pave the way for applications of BNT-based piezoceramics and significantly improve our understanding of the depolarization mechanism by optimizing the performance of lead-free piezoelectrics.

  1. 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.

  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 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

  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

    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.

  4. 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

  5. Fabrication of transparent lead-free KNN glass ceramics by incorporation method.

    PubMed

    Yongsiri, Ploypailin; Eitssayeam, Sukum; Rujijanagul, Gobwut; Sirisoonthorn, Somnuk; Tunkasiri, Tawee; Pengpat, Kamonpan

    2012-01-01

    The incorporation method was employed to produce potassium sodium niobate [KNN] (K0.5Na0.5NbO3) glass ceramics from the KNN-SiO2 system. This incorporation method combines a simple mixed-oxide technique for producing KNN powder and a conventional melt-quenching technique to form the resulting glass. KNN was calcined at 800C and subsequently mixed with SiO2 in the KNN:SiO2 ratio of 75:25 (mol%). The successfully produced optically transparent glass was then subjected to a heat treatment schedule at temperatures ranging from 525C -575C for crystallization. All glass ceramics of more than 40% transmittance crystallized into KNN nanocrystals that were rectangular in shape and dispersed well throughout the glass matrix. The crystal size and crystallinity were found to increase with increasing heat treatment temperature, which in turn plays an important role in controlling the properties of the glass ceramics, including physical, optical, and dielectric properties. The transparency of the glass samples decreased with increasing crystal size. The maximum room temperature dielectric constant (?r) was as high as 474 at 10 kHz with an acceptable low loss (tan?) around 0.02 at 10 kHz. PMID:22340426

  6. 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

  7. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2013-03-01

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

  9. 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.

  10. 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.

  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)BNTxBZH, 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)BNTxBZH 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??C/cm{sup 2}, 43.5??C/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. Combinatorial discovery of a lead-free morphotropic phase boundary in a thin-film piezoelectric perovskite

    E-print Network

    Rubloff, Gary W.

    perovskite S. Fujino,1,a M. Murakami,1 V. Anbusathaiah,2 S.-H. Lim,1 V. Nagarajan,2 C. J. Fennie,3 M. Wuttig with a simple perovskite structure using the combinatorial thin film strategy. The boundary is a rhombohedral at approximately Bi0.86Sm0.14FeO3 with dielectric constant and out-of-plane piezoelectric coefficient comparable

  13. High-Temperature Piezoelectric Ceramic Developed

    NASA Technical Reports Server (NTRS)

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

    2005-01-01

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

  14. 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 ?A, respectively, under repeated human finger impact. It has been demonstrated that the output volume power density of 10.8 ?W 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

  15. New (1 - x)K0.45Na0.55Nb0.96Sb0.04O3-xBi0.5Na0.5HfO3 lead-free ceramics: Phase boundary and their electrical properties

    NASA Astrophysics Data System (ADS)

    Tao, Hong; Wu, Jiagang; Zheng, Ting; Wang, Xiangjian; Lou, Xiaojie

    2015-07-01

    Here, we reported a high unipolar strain and large piezoelectricity in new (1 - x)K0.45Na0.55Nb0.96Sb0.04O3-xBi0.5Na0.5HfO3 ceramics. The rhombohedral-tetragonal (R-T) phase boundary was constructed in the ceramics with 0.03 < x ? 0.05, which shows a large d33 value of 419 pC/N. More importantly, a high unipolar strain of 0.31% was observed due to the multiphase coexistence. In addition, the piezoelectricity of the ceramics could be effectively enhanced if their compositions are located at the phase boundaries region, where a very low electric field of 1.2 kV/mm can readily rotate the R/T domains. We also noticed that the deviation from phase boundary induced by applying an external electric field results in the deterioration of piezoelectricity after the "second-poling" method. We believe that as a potassium-sodium-niobate based material, the ceramics developed in this work may find practical applications in lead-free piezoelectric devices such as actuators and fuel injectors in the future owing to the significant enhancement in their piezoelectricity as well as strain.

  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. Response of intergrown microstructure to an electric field and its consequences in the lead-free piezoelectric bismuth sodium titanate

    SciTech Connect

    Liu Yun; Noren, Lasse; Studer, Andrew J.; Withers, Ray L.; Guo Yiping; Li Yongxiang; Yang Hui; Wang Jian

    2012-03-15

    We investigate the R3c average structure and micro-structure of the ceramic Bi{sub 0.5}Na{sub 0.5}TiO{sub 3} (BNT) in situ under applied electric fields using diffraction techniques. Electron diffraction implies the presence of significant octahedral tilt twin disorder, corresponding to the existence of a fine scale intergrown microstructural (IGMS) 'phase' within the R3c rhombohedral average structure matrix. A careful neutron refinement suggests not only that the off-centre displacements of the cations relative to the oxygens in the R3c regions increases systematically on application of an electric field but also that the phase fraction of the IGMS regions increases systematically. The latter change in phase fraction on application of the electric field enhances the polar displacement of the cations relative to the oxygen anions and affects the overall strain response. These IGMS regions form local polar nano regions that are not correlated with one another, resulting in polarisation relaxation and strain behaviour observed in BNT-containing materials. - Graphical abstract: The intergrown microstructure at very fine scales within the R3c rhombohedral phase matrix of BNT, originating from octahedral tilt twinning disorder, will increase with respect to an external field. Highlights: Black-Right-Pointing-Pointer The existence of an intergrown microstructural 'phase' within the average structure matrix. Black-Right-Pointing-Pointer This phase fraction of the intergrown microstructural regions changes. Black-Right-Pointing-Pointer Such regions form local polar nano regions that are not correlated with one another.

  18. The structure and optical properties of lead-free transparent KNLTN-La0.01 ceramics prepared by conventional sintering technique

    NASA Astrophysics Data System (ADS)

    Yang, W. L.; Xiu, H. J.; Xiong, Y. L.; Wang, J.; Yuan, C. X.; Wei, J.; Zhou, Z. X.

    2014-12-01

    (Na0.52K0.44Li0.04)0.97La0.01Ta0.20Nb0.80O3 (KNLTN-La0.01) lead-free subtransparent ceramics was prepared by a conventional sintering technique. The structure and the optical properties of the ceramics were investigated. The room temperature crystallographic indexing revealed the ABO3 perovskite type, tetragonal phase and P4mm point group in the ceramics. The surface and fractured surface SEM micrographs showed a dense microstructure with few micropores in KNLTN-La0.01 ceramics, which was obviously better than for the pure KNLTN ceramics. The refractive indexes of the films were investigated by an ellipsometer and the results show that the KNLTN-La0.01 subtransparent ceramics reveals significant wavelength dependent dispersion. The refractive index ranges from 2.14 to 2.06 with the wavelength increase from 380 nm to 900 nm. The dispersive behavior was analyzed by three parameters of Cauchy dispersion model and the values of the parameters A, B and C are 2.06100.0005, 0.00540.0003 and 0.000690.00004, respectively.

  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. 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.

  1. 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 8001100?pm/V) in a relatively low driving electric field range (14?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 (12?kV/mm) and the enhanced domain switching (24?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.

  2. 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).

  3. 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.

  4. 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

  5. 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.

  6. Lead-free Ba0.8Ca0.2(ZrxTi1-x)O3 ceramics with large electrocaloric effect

    NASA Astrophysics Data System (ADS)

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

    2015-01-01

    The electrocaloric effect was investigated in lead-free Zr doped Ba0.8Ca0.2(ZrxTi1-x)O3 (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 (?T) using the Maxwell relation based on the P-E hysteresis loops measured at different temperatures. A large electrocaloric responsivity ?T/?E = 0.34 10-6 Km/V was found for x = 0.04, which significantly exceeds of values found so far in other lead-free electrocaloric materials.

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

    PubMed

    Crossley, Sam; Kar-Narayan, Sohini

    2015-08-28

    Energy harvesting from ubiquitous ambient vibrations is attractive for autonomous small-power applications and thus considerable research is focused on piezoelectric materials as they permit direct inter-conversion of mechanical and electrical energy. Nanogenerators (NGs) based on piezoelectric nanowires are particularly attractive due to their sensitivity to small-scale vibrations and may possess superior mechanical-to-electrical conversion efficiency when compared to bulk or thin-film devices of the same material. However, candidate piezoelectric nanowires have hitherto been predominantly analyzed in terms of NG output (i.e. output voltage, output current and output power density). Surprisingly, the corresponding dynamical properties of the NG, including details of how the nanowires are mechanically driven and its impact on performance, have been largely neglected. Here we investigate all realizable NG driving contexts separately involving inertial displacement, applied stress T and applied strain S, highlighting the effect of driving mechanism and frequency on NG performance in each case. We argue that, in the majority of cases, the intrinsic high resonance frequencies of piezoelectric nanowires (?tens of MHz) present no barrier to high levels of NG performance even at frequencies far below resonance (<1 kHz) typically characteristic of ambient vibrations. In this context, we introduce vibrational energy harvesting (VEH) coefficients ?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

  8. Energy harvesting performance of piezoelectric ceramic and polymer nanowires

    NASA Astrophysics Data System (ADS)

    Crossley, Sam; Kar-Narayan, Sohini

    2015-08-01

    Energy harvesting from ubiquitous ambient vibrations is attractive for autonomous small-power applications and thus considerable research is focused on piezoelectric materials as they permit direct inter-conversion of mechanical and electrical energy. Nanogenerators (NGs) based on piezoelectric nanowires are particularly attractive due to their sensitivity to small-scale vibrations and may possess superior mechanical-to-electrical conversion efficiency when compared to bulk or thin-film devices of the same material. However, candidate piezoelectric nanowires have hitherto been predominantly analyzed in terms of NG output (i.e. output voltage, output current and output power density). Surprisingly, the corresponding dynamical properties of the NG, including details of how the nanowires are mechanically driven and its impact on performance, have been largely neglected. Here we investigate all realizable NG driving contexts separately involving inertial displacement, applied stress T and applied strain S, highlighting the effect of driving mechanism and frequency on NG performance in each case. We argue that, in the majority of cases, the intrinsic high resonance frequencies of piezoelectric nanowires (?tens of MHz) present no barrier to high levels of NG performance even at frequencies far below resonance (<1 kHz) typically characteristic of ambient vibrations. In this context, we introduce vibrational energy harvesting (VEH) coefficients ?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.

  9. Lead-free In{sub 2}O{sub 3}-doped (Bi{sub 0.5}Na{sub 0.5}){sub 0.93}Ba{sub 0.07}TiO{sub 3} ceramics synthesized by direct reaction sintering

    SciTech Connect

    Zhou Taosheng; Huang Rongxia; Shang Xunzhong; Peng Fei; Guo Jianyong; Chai Liying; Gu Haoshuang; He Yunbin

    2007-04-30

    Lead-free (Bi{sub 0.5}Na{sub 0.5}){sub 0.93}Ba{sub 0.07}TiO{sub 3}-x wt %In{sub 2}O{sub 3} ceramics synthesized by direct reaction sintering have been studied. X-ray diffraction reveals that all (Bi{sub 0.5}Na{sub 0.5}){sub 0.93}Ba{sub 0.07}TiO{sub 3}-x wt %In{sub 2}O{sub 3} ceramics are of a perovskite structure with coexistence of rhombohedral and tetragonal phases. It is found that the direct reaction sintering promotes growing of ceramic grains while doping of In{sub 2}O{sub 3} contributes to inhibit and homogenize the grain growth, as shown by scanning electron microscopy. The ceramics show excellent piezoelectric and dielectric properties with thickness electromechanical coupling factor k{sub t}=0.503, piezoelectric constant d{sub 33}=205 pC/N, dielectric constant {epsilon}{sub 33}{sup T}/{epsilon}{sub 0}=1046, and loss tangent tan {delta}=0.036.

  10. 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.

  11. 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.

  12. Synthesis and Properties of [Bi0.5(Na1-xAgx)0.5]1-yBayTiO3 Piezoelectric Ceramics

    NASA Astrophysics Data System (ADS)

    Wu, Lang; Xiao, Ding-Quan; Lin, Dun-Min; Zhu, Jian-Guo; Yu, Ping

    2005-12-01

    A new group of ABO3-type lead-free piezoelectric ceramics, [Bi0.5(Na1-xAgx)0.5]1-yBayTiO3, was developed, and the corresponding invention patent was submitted. The ceramics were synthesized by the conventional ceramic sintering technique using electronic grade raw materials, and the preparation techniques are very stable and convenient. The crystalline phase, microstructure and electric properties of the ceramics were also investigated. All the ceramics have high densities of about 5.70-5.84 g/cm3, which are more than 95% of the theoretical values. This system provides high piezoelectric performances: d33=168 pC/N, kp=0.31 when x=0.06, y=0.06. Moreover, the samples doped with a moderate amount of Mn could increase the mechanical quality factor Qm and reduce the dielectric loss \\mathop{tg}? simultaneously. The temperature dependence of piezoelectric properties measured show that at up to 180C, d33 can still remain 126 pC/N for [Bi0.5(Na0.96Ag0.04)0.5]0.90Ba0.10TiO3 ceramics, which has a d33 of 137 pC/N at room temperature.

  13. 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.

  14. 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 0.41?C/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.

  15. 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.

  16. 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.

  17. 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).

  18. A study of piezoelectric properties of (Ba0.85Ca0.15)(Zr0.9Ti0.1)O3 ceramics synthesized by sol-gel process

    NASA Astrophysics Data System (ADS)

    Praveen, J. Paul; Kumar, Kranti; James Raju, C. K.; Das, Dibakar

    2013-06-01

    Lead free piezoelectric ceramics 'Barium calcium zirconium titanate (Ba0.85Ca0.15)(Zr0.9Ti0.1)O3 have been prepared by sol-gel synthesis method. The structure and piezoelectric properties were investigated for the given BCZT system. X-ray diffraction (XRD) and transmission electron microscope (TEM) studies confirmed the formation of single phase BCZT nanoparticles (<50nm). The calcined and compacted powders sintered at 1550C resulted in a complete perovskite structure. BCZT sample showed a high remnant polarization of 11.55 ?C/cm2 and a low coercive field (Ec) of 0.166 kV/cm. A high piezoelectric co-efficient of d33490 pC/N was obtained for the electrically poled sample. The study of microstructure on its piezoelectric properties of BCZT ceramics is discussed in this paper.

  19. Multiscale energy release rates in fracture of piezoelectric ceramics

    NASA Astrophysics Data System (ADS)

    Gao, Huajian; Fulton, Chandler C.; Zhang, Tong-Yi; Tong, Pin; Barnett, David M.

    1997-06-01

    The reliable use of piezoelectric ceramics as actuators in smart structures hinges on a fundamental understanding of the fracture process in these materials. However, despite the success of fracture mechanics theories in explaining the cracking behavior of a wide range of engineering materials, the extension of these accepted criteria to piezoelectrics fails to predict even qualitatively their response to combined electrical and mechanical loads. A new fracture criterion is presented here, in which a multiscale point of view is adopted in order to account for a zone of combined mechanical brittleness and electrical ductility near the crack tip. As a starting point for the investigations, we assume that the region of electrical nonlinearity is confined to aline segment ahead of the crack, analogous to the Dugdatle zone of plasticity in metals. This mathematical simplification represents the physical situation in which a distribution of excess electric dipoles is aligned on a finite segment in an otherwise linear piezoelectric solid. By applying this model to both insulated and conducting cracks subjected to far-field loading, we obtain local-scale energy release rates whose dependence on applied tractions and electric fields agrees with the trends observed experimentally. One important feature of the analytical expressions for crack driving force is that they are independent of the strength and size of the nonlinear zone.

  20. 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.

  1. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-03-01

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

  3. Cite this: CrystEngComm, 2013, 15, Large size lead-free (Na,K)(Nb,Ta)O3 piezoelectric single

    E-print Network

    Cao, Wenwu

    to ceramic form of materials due to the difficulty in growing large size crystals. Single crystals nature. Many methods have been adopted to grow KNN-based single crystals. Solid state crystal growth (SSCG) process was employed to grow crystals of 14 mm in size,16,17 but the crystals were porous

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

    NASA Technical Reports Server (NTRS)

    Bryant, Robert G.

    2007-01-01

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

  5. Fabrication of lead-free (Na{sub 0.82}K{sub 0.18}){sub 0.5}Bi{sub 0.5}TiO{sub 3} piezoelectric nanofiber by electrospinning

    SciTech Connect

    Chen, Y.Q.; Zheng, X.J.; Feng, X.; Dai, S.H.; Zhang, D.Z.

    2010-06-15

    (Na{sub 0.82}K{sub 0.18}){sub 0.5}Bi{sub 0.5}TiO{sub 3} nanofibers were synthesized by sol-gel process and electrospinning. Scanning electron microscopy was used to verify that the diameters and lengths are in the range of 150-600 nm and several hundreds of micrometer. Perovskite structure and grain size (20-70 nm) were verified by X-ray diffraction and transmission electron microscopy. The high effective piezoelectric coefficient d{sub 33} (96 pm/V) was measured by scanning force microscopy. It may be attributed to easily tilting the polar vector of domain for an electric field and the increase in the number of possible spontaneous polarization direction near the rhombohedral-tetragonal morphotropic phase boundary. The research shows that there are potentional applications for (Na{sub 0.82}K{sub 0.18}){sub 0.5}Bi{sub 0.5}TiO{sub 3} nanofiber in nanoscale lead-free piezoelectric devices.

  6. 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.

  7. 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 Cm-2K-1, 15.8 Pa-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.

  8. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2015-01-01

    Electrocaloric effect of lead-free Ba(Zr0.1Ti0.9)1-xSnxO3 (x=0 and x=0.075) ceramics is investigated. In the composition x=0, the electrocaloric strength (?) 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).

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

    PubMed

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

    2011-09-01

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

  11. Structural crossover from nonmodulated to long-period modulated tetragonal phase and anomalous change in ferroelectric properties in the lead-free piezoelectric N a1 /2B i1 /2Ti O3-BaTi O3

    NASA Astrophysics Data System (ADS)

    Rao, Badari Narayana; Khatua, Dipak Kumar; Garg, Rohini; Senyshyn, Anatoliy; Ranjan, Rajeev

    2015-06-01

    The highly complex structure-property interrelationship in the lead-free piezoelectric (x )N a1 /2B i1 /2Ti O3- (1 -x ) BaTi O3 is a subject of considerable contemporary debate. Using comprehensive x-ray, neutron diffraction, dielectric, and ferroelectric studies, we have shown the existence of a new criticality in this system at x =0.80 , i.e., well within the conventional tetragonal phase field. This criticality manifests as a nonmonotonic variation of the tetragonality and coercivity and is shown to be associated with a crossover from a nonmodulated tetragonal phase (for x <0.8 ) to a long-period modulated tetragonal phase (for x >0.80 ). It is shown that the stabilization of long-period modulation introduces a characteristic depolarization temperature in the system. While differing qualitatively from the two-phase model often suggested for the critical compositions of this system, our results support the view with regard to the tendency in perovskites to stabilize long-period modulated structures as a result of complex interplay of antiferrodistortive modes [Bellaiche and Iniguez, Phys. Rev. B 88, 014104 (2013), 10.1103/PhysRevB.88.014104; Prosandeev, Wang, Ren, Iniguez, ands Bellaiche, Adv. Funct. Mater. 23, 234 (2013), 10.1002/adfm.201201467].

  12. Comparison of several methods to characterise the high frequency behaviour of piezoelectric ceramics for transducer applications

    PubMed

    Tran-Huu-Hue; Levassort; Felix; Damjanovic; Wolny; Lethiecq

    2000-03-01

    Thickness mode resonances in commercial piezoelectric ceramics have been characterised as a function of frequency by two methods. The first is based on a fit on the electrical impedance for the fundamental and the overtones. This method has been applied to a large number of PZT ceramic samples and frequency dependence for all the parameters is investigated, in particular for the piezoelectric coefficient e33. The second is based on the measurement of the mechanical displacement at the centre of the surface of a PZT ceramic disk. With a modified KLM scheme, this displacement is modelled. The dielectric, elastic and piezoelectric parameters are extracted and compared for the fundamental and the third overtone. The results are found to be in good agreement. PMID:10829662

  13. 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.

  14. 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.

  15. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2013-09-01

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

  17. Influence of sample size on ultrasonic phase velocity measurements in piezoelectric ceramics

    E-print Network

    Cao, Wenwu

    dimensions are much smaller than the transducer. The accuracy of the ultrasonic data is very criticalInfluence of sample size on ultrasonic phase velocity measurements in piezoelectric ceramics Rui requirements is that the sample area should be much larger than the size of the transducer so that plane wave

  18. 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.

  19. High temperature lead-free relaxor ferroelectric: Intergrowth Aurivillius phase BaBi{sub 2}Nb{sub 2}O{sub 9}-Bi{sub 4}Ti{sub 3}O{sub 12} ceramics

    SciTech Connect

    Zhang Hongtao; Yan Haixue; Reece, Michael J.

    2010-05-15

    Intergrowth BaBi{sub 2}Nb{sub 2}O{sub 9}-Bi{sub 4}Ti{sub 3}O{sub 12} (BaBi{sub 6}Ti{sub 3}Nb{sub 2}O{sub 21}) Aurivillius phase ceramic has been found to be a relaxor ferroelectric (RFE) with the highest reported temperature of the maximum of the dielectric permittivity (T{sub m}) of all of the known RFE systems. Dielectric characterization revealed that it has two dielectric anomalies. The first one is a frequency independent broad dielectric constant peak at {approx}280 deg. C, while the second anomaly shows relaxor behavior at 636 deg. C (100 kHz). There is obvious frequency dispersion of dielectric response at room temperature, which is in agreement with dielectric properties of a typical relaxor. Ferroelectric hysteresis loops and a measurable value of piezoelectric constant d{sub 33} confirmed the ferroelectric nature of BaBi{sub 6}Ti{sub 3}Nb{sub 2}O{sub 21} ceramics. The piezoelectric response remained even after annealing at temperatures above 636 deg. C.

  20. 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

  1. 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.

  2. 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.

  3. 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 Mssbauer, and specific heat measurements of polycrystalline BaTi{sub 1x}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 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.

  4. Electrostrictive and relaxor ferroelectric behavior in BiAlO3-modified BaTiO3 lead-free ceramics

    NASA Astrophysics Data System (ADS)

    Zheng, Shaoying; Odendo, Erika; Liu, Laijun; Shi, Danping; Huang, Yanming; Fan, Longlong; Chen, Jun; Fang, Liang; Elouadi, Brahim

    2013-03-01

    The crystal structure of (1-x)BaTiO3-xBiAlO3 (x = 0, 0.02, 0.05, 0.08, and 0.1) ceramics was determined using X-ray diffraction and Raman spectroscopy at room temperature, which revealed a phase transition from tetragonal to rhombohedral with increasing x. The dielectric properties were studied as a function of temperature at different frequencies, which indicated that the phase transition temperature (Tm) decreased with increasing x. The relaxor behavior was observed by frequency and temperature dependent dielectric permittivity. The Lorenz-type quadratic law was used to characterize the dielectric permittivity peaks near Tm of high-temperature slopes at 1 MHz. The temperatures Tm of dielectric permittivity peaks fit very well with the Vogel-Fulcher law in x = 0.05 and x = 0.1. The polarization hysteresis loops and electrostrictive were displayed at room temperature. The sample for x = 0.1 exhibits a slim loop with negligible hysteresis and a subtle linear feature, which is a promising transducer material for use as an active element.

  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. 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.

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

    NASA Astrophysics Data System (ADS)

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

    1994-05-01

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

  8. 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.

  9. 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

  10. Synthesis and characterization of lead-free 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 ceramic

    NASA Astrophysics Data System (ADS)

    Coondoo, Indrani; Panwar, Neeraj; Amorn, Harvey; Alguero, Miguel; Kholkin, A. L.

    2013-06-01

    Polycrystalline sample of lead-free 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 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 C as the temperature of maximum permittivity. The macroscopic values of d33 and d31 were 350 pC/N and -141 pm/V, whereas the electromechanical coupling factors kp and kt were 44.5% and 41.6%, respectively. Bulk P-E hysteresis loop was obtained with saturation polarization 11 ?C/cm2 and coercive field 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 ?m and 827 nm, respectively. Local hysteresis loop with apparent coercive voltage, Vc = 15.8 V, was observed.

  11. Loss phenomenology and the methodology to derive loss factors in piezoelectric ceramics

    NASA Astrophysics Data System (ADS)

    Zhuang, Yuan

    The key factor for the miniaturization of piezoelectric devices is the power density, which is limited by the heat generation or internal losses. With accelerating the commercialization of piezoelectric actuators and transducers, it becomes more and more significant to clarify the loss phenomenology, reduce the hysteresis losses, and increase the mechanical quality factor to enhance the efficiency and performance. There are three loss components for piezoelectric vibrators, i.e., dielectric, elastic and piezoelectric losses. These loss factors are related with mechanical quality factors, which are the figure of merit of the material or device in the sense of efficiency. In order to obtain the mechanical quality factor Qm, IEEE standard provided the measurement method using the resonance and antiresonance frequencies. However, this characterization assumes that the Q value at resonance is equal to the one at antiresonance all the time, which is not consistent with experiment results. For practical materials there is sometimes a big difference between the mechanical quality factors of the resonance (QA) and the antiresonance (QB), and in most cases higher QB can be observed. Therefore, in recent several years we are focusing on a new resonance AC drive methodology to measure the admittance curve accurately around both the resonance and antiresonance peaks for piezoelectric materials, from which QA and QB can be derived by the 3dB method. Various piezoelectric materials were characterized with this technique. Further, the equations were derived showing the relations between quality factors and loss factors by the complex analysis of the admittance/ impedance expressions for specific piezoelectric vibrators. Using QA, Q B, and the electromechanical coupling factor k, we can obtain three types of loss factors precisely. Among various vibration modes of piezoelectric vibrators, we focus on k31, kt, k33, k p, and k15 modes, which cover all the 20 parameters of the ferroelectric material with infinitymm/6mm crystal symmetry, i.e. piezoelectric ceramic. Plus some other derivations using the fundamental correlations, 20 loss factors can be obtained for all parameters. Using this technique the piezoelectric loss factor is confirmed to be comparable to dielectric and elastic losses and it is the factor that determines whether QB is larger than QA, though it was previously neglected by most researchers. After getting the full loss matrices, the loss anisotropy was accordingly discussed, and the extensive loss factor was verified to be smaller than the intensive one. This methodology is an essential supplement to the current IEEE standard on piezoelectric characterization. The simplicity and accuracy of this technique are very attractive, and hopefully this proposal will be widely accepted as a standard in the piezoelectric community in the future. The inclusion of three loss factors is important for the admittance analysis and thermal simulation of piezoelectric devices in the "finite element method" software. Furthermore, taking into account the piezoelectric loss in addition to the dielectric and elastic ones, a new domain dynamic model will be established. Our phenomenological solution can be directly applied for the high power characterization methodology to clarify various materials' loss performances, and a principle for preparing high power density piezoelectric materials will be developed in the future.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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 120260?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 ? 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 510?nm were revealed by high-resolution transmission electron microscope. The normal piezoelectric coefficient d{sub 33} exhibits a rapid increase at E?=?1520?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.

  2. 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.

  3. Elastic constants measured from acoustic wave velocities in barium titanate piezoelectric ceramics

    NASA Astrophysics Data System (ADS)

    Ogawa, Toshio; Ikegaya, Taiki

    2015-01-01

    The longitudinal and transverse wave velocities in barium titanate (BT) ceramics sintered at different firing temperatures were measured using an ultrasonic precision thickness gauge with high-frequency pulse generation to evaluate elastic constants, such as Youngs modulus and Poissons ratio. With increasing firing temperature, the longitudinal and transverse wave velocities increased; as a result, Youngs modulus increased because of BT ceramics being mechanically hard. Poissons ratio after DC poling, however, was almost independent of the firing temperature. It was confirmed that there was an important factor for generating piezoelectricity regarding changes in Youngs modulus and Poissons ratio after DC poling compared with those before DC poling, that is, lowering Youngs modulus and increasing Poissons ratio. Furthermore, the modulus of rigidity and bulk modulus increased with the firing temperature because of the increase in ceramic bulk density. The modulus of rigidity decreased and the bulk modulus increased during DC poling because of domain alignment.

  4. 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.

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

    SciTech Connect

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

    2014-10-20

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

  6. 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.

  7. Dielectric, piezoelectric, and pyroelectric properties of lead zirconate-lead zinc niobate ceramics

    SciTech Connect

    Takenaka, T. ); Bhalla, A.S.; Cross, L.E. . Materials Research Lab.); Sakata, K. . Faculty of Science and Technology)

    1989-06-01

    This paper reports on piezoelectric and pyroelectric ceramics consisting of antiferroelectric lead zirconate (PZ) and relaxor ferroelectric lead zinc niobate (PZN) studied from an application viewpoint of the field-induced antiferroelectric-to-ferroelectric phase transition. An antiferroelectric-to-ferroelectric phase transition. An antiferroelectric-ferroelectric phase boundary exists in PbZr{sub x}(Zn{sub 1/3}Nb{sub 2/3}){sub 1 {minus} x}O{sub 3}(PZZN-1000x) close to x = 0.93 to 0.94 at room temperature. A new ferroelectric rhombohedral phase change, F{alpha}-F'{alpha} at low temperature is found and studied by the temperature dependence of the pyroelectric coefficient. Electrical poling in these ceramics is easy, and the coercive field E{sub c} {approx} 8 to 10 kV/cm is rather low. Samples with compositions in the range PZZN-86 to PZZN-92 have a large electromechanical coupling constant, k (k, and k {sub 15} {approx} 50% to 60%), and a low dielectric constant, {epsilon}{sub s}, ({epsilon}{sup T}{sub 33}/{epsilon}{sub 0} = 260 to 320, {epsilon}{sup T}{sub 11} {epsilon}{sub 0} = 380). PZZN ceramics appear to be potential candidates for high-frequency ultrasonic transducers used in the thickness shear mode. The pyroelectric figure of merit (F{sub v}) of these ceramics is comparable to the values published for the PZT-based or PbTiO{sub 3}-based materials.

  8. 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.

  9. 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.

  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. 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.

  12. 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.

  13. 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(?) 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.

  14. 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

  15. Phase diagram of (1-x%)(0.89Bi0.5Na0.5TiO3-0.06BaTiO3-0.05K0.5Na0.5NbO3)-x%MnO2 lead-free anti-ferroelectric ceramics

    NASA Astrophysics Data System (ADS)

    Gao, Feng; Dong, Xianlin; Mao, Chaoliang; Cao, Fei; Wang, Genshui

    2012-09-01

    A phase diagram for the lead-free ceramics in the (1-x%)(0.89Bi0.5Na0.5TiO3-0.06BaTiO3-0.05K0.5Na0.5NbO3)-x%MnO2 (BNBKN-x%Mn) binary system is constructed for the first time based on the ferroelectric and dielectric measurements. The ferroelectric behaviors under different temperatures suggest that the ceramics are basically of relaxor anti-ferroelectric nature near room temperature. The temperature dependent dielectric properties show that when the addition of MnO2 increases, the relaxor anti-ferroelectric phase can be stabilized to be close to the Curie point, which corresponds to a relaxor anti-ferroelectric to paraelectric phase transition.

  16. 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.

  17. 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.

  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. 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

  20. 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

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

    PubMed

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

    2014-05-14

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

  2. 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.

  3. 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.

  4. Piezoelectric Ultrasonic Micromotors

    E-print Network

    Flynn, Anita M.

    1995-06-01

    This report describes development of micro-fabricated piezoelectric ultrasonic motors and bulk-ceramic piezoelectric ultrasonic motors. Ultrasonic motors offer the advantage of low speed, high torque operation without ...

  5. 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.

  6. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-09-01

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

  8. 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.

  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. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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 20160?C and electric fields of 0.14 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.

  16. 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

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. Morphotropic phase boundary and electric properties in (1-x)Bi0.5Na0.5TiO3-xBiCoO3 lead-free piezoelectric ceramics

    E-print Network

    Cao, Wenwu

    of Physics. Related Articles Structural diversity of the (Na1-xKx)0.5Bi0.5TiO3 perovskite at the morphotropic frequency of dielectric relaxation associated with domain-wall motion in Sb5+- modified (K,Na)NbO3-basedC/N, and 0.45, respectively. The low temperature humps of relative dielectric constant, which is indicative

  5. 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.

  6. 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.

  7. 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.

  8. 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

    E-print Network

    Cao, Wenwu

    and low dielectric loss (d33 360 pC/N, d31 113 pC/N, d15 162 pC/N, k33 0.720, kt 0.540, and tan, high Curie temperature, and relatively good piezoelectric properties.1,2 Among these NBT-based solid- position of x 0.06 0.07.68 It has been reported that the piezoelectric constant d33 of In2O3 doped 0

  9. 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.

  10. 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.

  11. Enhanced piezoelectric performance of (0.98-x)Bi(Sc{sub 3/4}In{sub 1/4})O{sub 3}-xPbTiO{sub 3}-0.02Pb(Zn{sub 1/3}Nb{sub 2/3})O{sub 3} ternary high temperature piezoelectric ceramics

    SciTech Connect

    Chen Jianguo; Zhao Tianlong; Cheng Jinrong; Dong Shuxiang

    2013-04-14

    (0.98-x)Bi(Sc{sub 3/4}In{sub 1/4})O{sub 3}-xPbTiO{sub 3}-0.02Pb(Zn{sub 1/3}Nb{sub 2/3})O{sub 3} (BSI-PT-PZN) high temperature piezoelectric ceramics were prepared by traditional solid-state reaction method. Combining X-ray diffraction results with piezoelectric data, it was found that the morphotropic phase boundary (MPB) occurred at x = 0.575. The piezoelectric constant d{sub 33}, curie temperature T{sub c}, and electromechanical coupling factor k{sub p} of BIS-PT-PZN ceramics with MPB composition were 427 pC/N, 412 Degree-Sign C, and 0.51, respectively. Furthermore, the strain of BIS-PT-PZN ceramics reached up to 0.25% under the electric field of 40 kV/cm. Temperature-dependent electromechanical coupling coefficient for MPB composition was stable from room temperature up to 350 Degree-Sign C. The piezoelectric properties of BIS-PT-PZN ceramics were comparable to that of 0.36BiScO{sub 3}-0.64PbTiO{sub 3} (BS-PT) ceramics, and the piezoelectric constant d{sub 33} of BIS-PT-PZN ceramics was about twice that of our previous reported 0.4Bi(Sc{sub 3/4}In{sub 1/4})O{sub 3}-0.6PbTiO{sub 3} (BSI-PT) ceramics. The reduction in the expensive Sc{sub 2}O{sub 3} content and comparable piezoelectric properties with BS-PT ceramics indicated that BIS-PT-PZN ceramics were promising for commercial applications as high temperature actuators and sensors.

  12. 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.

  13. 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.

  14. Phase coexistence and high electrical properties in (K{sub x}Na{sub 0.96-x}Li{sub 0.04})(Nb{sub 0.85}Ta{sub 0.15})O{sub 3} piezoelectric ceramics

    SciTech Connect

    Chang Yunfei; Yang Zupei; Ma Difei; Liu Zonghuai; Wang Zenglin

    2009-03-01

    (K{sub x}Na{sub 0.96-x}Li{sub 0.04})(Nb{sub 0.85}Ta{sub 0.15})O{sub 3} lead-free piezoelectric ceramics were produced by conventional solid-state reaction method. The effects of K/Na ratio on the phase transitional behavior, Raman spectrum, microstructure, and dielectric, piezoelectric, and ferroelectric properties of the ceramics have been investigated. The phase structure of the ceramics undergoes a transition from orthorhombic to tetragonal phase with increasing x. A double-degenerate symmetric O-Nb-O stretching vibration v{sub 1} and a triply degenerate symmetric O-Nb-O bending vibration v{sub 5} are detected as relatively strong scattering in the Raman spectra. The peak shifts of v{sub 5} and v{sub 1} modes all have a discontinuity with x between 0.42 and 0.46, which may suggest the coexistence of orthorhombic and tetragonal phases in this range. Properly modifying x reduces the sintering temperature, promotes the grain growth behavior, and improves the density of the ceramics. The polymorphic phase transition (at T{sub o-t}) is shifted to near room temperature by increasing x to 0.44 (K/Na ratio of about 0.85:1), and the coexistence of orthorhombic and tetragonal phases in the ceramics at x=0.44 results in the optimized electrical properties (d{sub 33}=291 pC/N, k{sub p}=0.54, {epsilon}{sub r}=1167, tan {delta}=0.018, T{sub o-t}=35 deg. C, T{sub C}=351 deg. C, P{sub r}=27.65 {mu}C/cm{sup 2}, and E{sub c}=8.63 kV/cm). The results show that the equal K/Na ratio is not an essential condition in obtaining optimized electrical properties in (K{sub x}Na{sub 0.96-x}Li{sub 0.04})(Nb{sub 0.85}Ta{sub 0.15})O{sub 3} ceramics.

  15. The application of high permittivity piezoelectric ceramics to 2D array transducers for medical imaging.

    PubMed

    Felix, N; Tran-Huu-Hue, L P; Walker, L; Millar, C; Lethiecq, M

    2000-03-01

    Two-dimensional (2D) array transducers have become of great interest in the last few years, in view of real-time volumetric ultrasonic imaging. The electrical matching between the high electrical impedance of elements and the standard cables and electronics is one of the key issues in 2D array design. The use of high-permittivity ceramics such as PNNZT either in bulk configuration or in 1-3 piezocomposites decreases the electrical impedance. In this paper, bulk samples of PNNZT and PZT ceramics are characterised, and results are compared. 2D array elements are then manufactured and their electrical impedances measured. Theoretical predictions of homogenisation models for 1-3 piezocomposites allow the simulation of the electroacoustic behaviour of 2D array elements. Results for both piezocomposite and bulk materials can be obtained. Calculations of the input impedance, the sensitivity and the bandwidth of the different configurations are compared and discussed. These results demonstrate the advantages of the PNNZT compositions over standard PZT. PMID:10829643

  16. Visible and infrared transparency in lead-free bulk BaTiO(3) and SrTiO(3) nanoceramics.

    PubMed

    Liu, Jing; Shen, Zhijian; Yao, Wenlong; Zhao, Yonghao; Mukherjee, Amiya K

    2010-02-19

    Multifunctional transparent ferroelectric ceramics have widespread applications in electro-optical devices. Unfortunately, almost all currently used electro-optical ceramics contain a high lead concentration. In this work, via coupling of spark plasma sintering with high pressure, we have successfully synthesized bulk lead-free transparent nanostructured BaTiO(3) (abbreviated as BTO) and SrTiO(3) (STO) ceramics with excellent optical transparency in both visible and infrared wavelength ranges. This success highlights potential ingenious avenues to search for lead-free electro-optical ceramics. PMID:20081287

  17. 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.

  18. 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.

  19. Lead-free KNbO3 ferroelectric nanorod based flexible nanogenerators and capacitors.

    PubMed

    Jung, Jong Hoon; Chen, Chih-Yen; Yun, Byung Kil; Lee, Nuri; Zhou, Yusheng; Jo, William; Chou, Li-Jen; Wang, Zhong Lin

    2012-09-21

    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 KNbO(3) ferroelectric nanorods (~1 ?m length) with piezoelectric coefficient (d(33) ~ 55 pm V (-1)). A flexible piezoelectric nanogenerator is mainly composed of KNbO(3)-poly(dimethylsiloxane) (PDMS) composite sandwiched by Au/Cr-coated polymer substrates. We deposit a thin poly(methyl methacrylate) (PMMA) layer between the KNbO(3)-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 KNbO(3)-PDMS composite device shows a nearly frequency-independent dielectric constant (~3.2) and low dielectric loss (<0.006) for the frequency range of 10(2)-10(5) 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. PMID:22922486

  20. 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.

  1. 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

  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, 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.

  3. 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.

  4. Effects of sintering aid CuTa{sub 2}O{sub 6} on piezoelectric and dielectric properties of sodium potassium niobate ceramics

    SciTech Connect

    Yang, Song-Ling; Tsai, Cheng-Che; Hong, Cheng-Shong; Chu, Sheng-Yuan; Center for Micro/Nano Science and Technology and Research Center for Energy Technology and Strategy, National Cheng Kung University, Tainan 701, Taiwan, ROC

    2012-04-15

    Graphical abstract: NKN ceramics with a sintering aid CuTa{sub 2}O{sub 6} (CT) doping increased the mechanical quality factor (Q{sub m}) and electromechanical coupling factor (k{sub p}). Highlights: Black-Right-Pointing-Pointer A new sintering aid CuTa{sub 2}O{sub 6} was developed to dope into NKN ceramics. Black-Right-Pointing-Pointer Dense NKN ceramics were obtained as CuTa{sub 2}O{sub 6} compound doping. Black-Right-Pointing-Pointer We find the soluble limit of CuTa{sub 2}O{sub 6} compound incorporated into NKN ceramics. Black-Right-Pointing-Pointer The maximum Q{sub m} and k{sub p} values were more than 1500 and 42%, respectively. Black-Right-Pointing-Pointer CuTa{sub 2}O{sub 6} compound is a better sintering aid compared with K{sub 5.3}Cu{sub 1.3}Ta{sub 10}O{sub 29}. -- Abstract: In this study, the effects of a sintering aid CuTa{sub 2}O{sub 6} (CT) on (Na{sub 0.5}K{sub 0.5})NbO{sub 3} (NKN) ceramics were investigated. The diffracted angles in XRD profiles decreased because the Nb-sites were replaced by Cu and Ta ions, causing the expansion of lattice volume. SEM images showed smaller grain sizes at a low concentration of CuTa{sub 2}O{sub 6}, and grain sizes increased as the concentration of CuTa{sub 2}O{sub 6} doping increased because of a liquid phase formed. When CuTa{sub 2}O{sub 6} dopants were doped into NKN ceramics, the T{sub O-T} and T{sub c} phase transitions decreased because the replacement of Ta{sup 5+} ions in the B-site. A high bulk density (4.595 g/cm{sup 3}) and electromechanical coupling factor (k{sub p}, k{sub t}) were enhanced when CT dopants were doped into NKN ceramics. Moreover, the mechanical quality factor (Q{sub m}) also increased from 67 to 1550. NKN ceramics with sintering aid CuTa{sub 2}O{sub 6} doping showed excellent piezoelectric properties: k{sub p}: 42.5%; k{sub t}: 49.1%; Q{sub m}: 1550; and d{sub 33}: 96 pC/N.

  5. 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.

  6. NASA-DoD Lead-Free Electronics Project

    NASA Technical Reports Server (NTRS)

    Kessel, Kurt R.

    2009-01-01

    The primary technical objective of this project is to undertake comprehensive testing to generate information on failure modes/criteria to better understand the reliability of: (1) Packages (e.g., Thin Small Outline Package [TSOP], Ball Grid Array [BGA], Plastic Dual In-line Package [PDIP]) assembled and reworked with lead-free alloys, (2) Packages (e.g., TSOP, BGA, PDIP) assembled and reworked with mixed (lead/lead-free) alloys.

  7. NASA-DoD Lead-Free Electronics Project

    NASA Technical Reports Server (NTRS)

    Kessel, Kurt

    2010-01-01

    Original Equipment Manufacturers (OEMs), depots, and support contract ors have to be prepared to deal with an electronics supply chain that increasingly provides parts with lead-free finishes, some labeled no differently and intermingled with their SnPb counterparts. Allowance of lead-free components presents one of the greatest risks to the r eliability of military and aerospace electronics. The introduction of components with lead-free terminations, termination finishes, or cir cuit boards presents a host of concerns to customers, suppliers, and maintainers of aerospace and military electronic systems such as: 1. Electrical shorting due to tin whiskers 2. Incompatibility of lead-f ree processes and parameters (including higher melting points of lead -free alloys) with other materials in the system 3. Unknown material properties and incompatibilities that could reduce solder joint reli ability As the transition to lead-free becomes a certain reality for military and aerospace applications, it will be critical to fully un derstand the implications of reworking lead-free assemblies.

  8. 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.

  9. Wide Compositional Range In Situ Electric Field Investigations on Lead-Free Ba (Zr0.2Ti0.8)O3-x (Ba0.7Ca0.3)TiO3 Piezoceramic

    NASA Astrophysics Data System (ADS)

    Zakhozheva, M.; Schmitt, L. A.; Acosta, M.; Guo, H.; Jo, W.; Schierholz, R.; Kleebe, H.-J.; Tan, X.

    2015-06-01

    The evolution of ferroelectric domains in the lead-free Ba (Zr0.2Ti0.8)O3-x (Ba0.7Ca0.3)TiO3 (abbreviated as BZT -x BCT ) piezoelectric ceramic is investigated in situ under an applied electric field using transmission electron microscopy (TEM). Poling-induced, reversible, transformation from a multidomain to a single-domain state is monitored for a large variety of compositions. For all studied materials, this transformation occurs with the appearance of an intermediate nanodomain state at moderate poling fields. According to our results, under high poling fields, a single-domain state vanishes and multiple domains reappear within the grains. Upon further cycling, switching between two different multidomain states occurs. For all BZT -x BCT compositions that we investigate, no sign of the electric-field-induced structural changes is detected using the selected area electron-diffraction (SAED) patterns, which are devoid of the reflection splitting or any detectable changes during electrical poling. The extrinsic contribution to the piezoelectric properties is found to dominate in the BZT -x BCT piezoceramic.

  10. 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).

  11. 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.

  12. 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.

  13. Lead-free BaTiO3 nanowires-based flexible nanocomposite generator.

    PubMed

    Park, Kwi-Il; Bae, Soo Bin; Yang, Seong Ho; Lee, Hyung Ik; Lee, Kisu; Lee, Seung Jun

    2014-08-01

    We have synthesized BaTiO3 nanowires (NWs) via a simple hydrothermal method at low temperature and developed a lead-free, flexible nanocomposite generator (NCG) device by a simple, low-cost, and scalable spin-coating method. The hydrothermally grown BaTiO3 NWs are mixed in a polymer matrix without a toxic dispersion enhancer to produce a piezoelectric nanocomposite (p-NC). During periodical and regular bending and unbending motions, the NCG device fabricated by utilizing a BaTiO3 NWs-polydimethylsiloxane (PDMS) composite successfully harvests the output voltage of ? 7.0 V and current signals of ? 360 nA, which are utilized to drive a liquid crystal display (LCD). We also characterized the instantaneous power (? 1.2 ?W) of the NCG device by calculating the load voltage and current through the connected external resistance. PMID:24967905

  14. 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.

  15. 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.

  16. ceramics

    NASA Astrophysics Data System (ADS)

    Liu, G.; Liu, X. Q.; Chen, X. M.

    2014-09-01

    The dielectric properties of Sm1.5Sr0.5NiO4- ? ceramics with different concentrations of oxygen vacancies were characterized. The ceramics with lower concentration of oxygen vacancies were prepared by directly sintering the sol-gel derived powders in air, while the higher one could be obtained by annealing the as-sintered ceramics in the flow of nitrogen. The post-densification annealing in the flow of nitrogen decreased the dielectric constant at low temperature and increased it at high temperature, while the dielectric loss increased in overall temperature range. The activation energy of low-temperature dielectric relaxation decreased with increasing the concentration of oxygen vacancies, and so did that of bulk electrical resistances although the values of resistances increased, while the activation energy of electrical resistances for grain boundary increased though the values of resistances decreased. The giant dielectric response in the as-sintered Sm1.5Sr0.5NiO4- ? ceramics should be mainly attributed to the small polaronic hopping process, while that of annealed ceramics should be directly linked to the oxygen vacancies.

  17. Nonlinear coefficients in lead-free CuO-(K,Na)NbO3 transducers

    NASA Astrophysics Data System (ADS)

    Liu, Yaoyang; Morita, Takeshi

    2015-07-01

    Hard piezoelectric materials usually require to be driven at a high vibration level. However, piezoelectrics under high stress show significant nonlinear behavior, which should be taken as one of the criteria. In this study, nonlinearity in lead-free CuO-(K,Na)NbO3 (CuO-KNN) transducers was investigated. In the burst-mode measurement, the transducers began free vibration after being excited by a burst voltage. The velocity decay rate and resonance frequency obtained from the velocity-time curve show high dependence on velocity amplitude. On the other hand, in the measured admittance curves at high voltage, around the resonant frequency, the values are not consecutive (jumping phenomenon); also, a hysteresis appears between the upward and downward sweeps, indicating the existence of nonlinearity. A model containing the nonlinear terms was proposed and adopted for fitting the admittance curves. From the curve fitting, the nonlinear coefficients and force factor of the CuO-KNN transducers could be determined and compared with those of Pb(Zr,Ti)O3 transducers.

  18. Investigation of high Curie temperature (1-x)BiSc{sub 1-y}Fe{sub y}O{sub 3}-xPbTiO{sub 3} piezoelectric ceramics

    SciTech Connect

    Sterianou, I.; Sinclair, D. C.; Reaney, I. M.; Comyn, T. P.; Bell, A. J.

    2009-10-15

    Ceramics around the morphotropic phase boundary (MPB) in the (1-x)BiSc{sub 1-y}Fe{sub y}O{sub 3}-xPbTiO{sub 3} solid solution were fabricated. For y=0.5, ceramics were single phase, and piezoelectric coefficients (d{sub 33}) and electromechanical coupling coefficients (k{sub p}) for MPB compositions were 300 pC/N and 0.49, respectively; a level of piezoelectric activity similar to that of hard, lead zirconate titanate compositions but with T{sub C}approx60 deg. C higher at approx440 deg. C. For ceramics with y>=0.7, dielectric measurements in combination with diffraction contrast transmission electron microscopy revealed the existence of two ferroelectric phases for most PbTiO{sub 3} contents studied. The presence of two ferroelectric phases was associated with a decrease in piezoelectric activity and although raw materials costs for y=0.7 and 0.8 with respect to y=0 were significantly lower (less Sc{sub 2}O{sub 3}) and T{sub C} greater (approx500 deg. C), d{sub 33} (approx100 pC/N) and k{sub p} (0.18) were too low to be commercially useful for actuator applications.

  19. Ferroelectric, dielectric and piezoelectric properties of Sr{sub 0.6}(BiNa){sub 0.2}Bi{sub 2}Nb{sub 2}O{sub 9} ceramics

    SciTech Connect

    Fang, Pinyang Xi, Zengzhe; Long, Wei; Li, Xiaojuan

    2013-11-15

    Graphical abstract: The oxygen vacancy was confirmed by the left figure and the role of oxygen vacancy on the piezoelectric properties was discussed. - Highlights: The d{sub 33}, ? and T{sub c} were found to be 22 pC/N, ? ? 10{sup 6} ? cm and 586 C. The electromechanical properties: k{sub p} ? 5.0%, k{sub t} ? 8.7% and Q{sub m} ? 651. The oxygen vacancy is responsible for electrical properties at high temperature. - Abstract: Aurivillius-type ceramic, Sr{sub 0.6}(BiNa){sub 0.2}Bi{sub 2}Nb{sub 2}O{sub 9} (SBNBN), was synthesized by using conventional solid-state processing. Phase structure and microstructural morphology were confirmed by X-ray diffraction analyses (XRD) and the scanning electron microscopy (SEM). Dielectric, piezoelectric and electromechanical properties of the SBNBN ceramic were investigated in detail. Curie temperature (T{sub c}), piezoelectric coefficient (d{sub 33}), electromechanical coupling coefficient k{sub p}, k{sub t} and quality factor Q{sub m} of the SBNBN ceramic were found to be 586.5 C, 22 pC/N, 5.0%, 8.7% and 651, respectively. In addition, the reasons for varieties of the resistivity and dielectric properties at high temperature were also discussed.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  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. 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.

  8. 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.

  9. 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 ?33 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.

  10. Ferroelectric and octahedral tilt twin disorder and the lead-free piezoelectric, sodium potassium niobate system

    SciTech Connect

    Schiemer, Jason; Withers, Ray L.; Liu, Yun; Yi, Zhiguo

    2012-11-15

    Using electron diffraction, trends in the local structural behaviour of the K{sub x}Na{sub 1-x}NbO{sub 3} (KNN x) 'solid solution' system are investigated and interpreted using an order/disorder based theoretical framework. At room temperature, electron diffraction shows a single plane of transverse polarised, diffuse intensity perpendicular to [0 1 0]{sub p} Low-Asterisk (p for parent sub-structure) across the entire phase diagram, indicative of ferroelectric disorder along the [0 1 0]{sub p} direction co-existing with long range ferroelectric order along the orthogonal [1 0 0]{sub p} and [0 0 1]{sub p} directions. An additional characteristic pattern of diffuse scattering is also observed, involving rods of diffuse intensity running along the [1 0 0]{sub p}* and [0 0 1]{sub p}* directions of the perovskite sub-structure and indicative of octahedral tilt disorder about the [1 0 0]{sub p} and [0 0 1]{sub p} axes co-existing with long range ordered octahedral tilting around the [0 1 0]{sub p} direction. A possible crystal chemical explanation for the existence of this latter octahedral tilt disorder is explored through bond valence sum calculations. The possible influence of both types of disorder on the previously refined, room temperature space group/s and average crystal structure/s is examined. - Graphical abstract: [-3,0.-1]p zone axis EDP of K{sub 0.46}Na{sub 0.54}NbO{sub 3} indexed according to both the relevant Pcm21 space groups (no subscripts) and the parent perovskite subcell (denoted by a subscript p). Highlights: Black-Right-Pointing-Pointer Characterises ferroelectric and octahedral tilt disorder in the KNN solid solution. Black-Right-Pointing-Pointer Discusses the possible driving forces for this disorder. Black-Right-Pointing-Pointer Discusses the implications of this disorder for physical properties. Black-Right-Pointing-Pointer Discusses the effects of this disorder on powder diffraction data.

  11. 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.

  12. 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 ?m to 0.35 0.13 ?m 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 (?) 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 (?' = 1139 at 1 MHz). The sample with x = 1.0, shown a high dielectric permittivity (?' = 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(?ac)] 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.

  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. 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

  15. Enhanced piezoelectricity in broad composition range and the temperature dependence research of (Ba1-xCax)(Ti0.95Sn0.05)O3 piezoceramics

    NASA Astrophysics Data System (ADS)

    Chen, Mingli; Xu, Zhijun; Chu, Ruiqing; Qiu, Hong; Li, Min; Liu, Yong; Shao, Lin; Ma, Shuai; Ji, Wanbin; Li, Wei; Gong, Shuwen; Li, Guorong

    2014-01-01

    BaTiO3-based (Ba1-xCax)(Ti0.95Sn0.05)O3 (x=0-0.07) lead-free piezoceramics were fabricated by a conventional solid state reaction technique. The phase structure and electrical properties of the as-prepared ceramics were researched. The temperature (TO-T) of the orthorhombic-tetragonal phase transition dielectric peak shifts toward lower temperature with increasing Ca content and the Curie temperature (TC) almost does not shift. At room temperature, the polymorphic phase transition (PPT) from the orthorhombic phase to tetragonal phase is jointly identified by the ?r-T curves and XRD patterns. The piezoelectricity of the ceramics is enhanced due to the polymorphic phase transition and the best piezoelectricity is obtained at x=0.02 with d33=464 pC/N and kp=43.1%. The piezoelectricity is enhanced in the broad composition range x=0.01-0.06 with d33>400 pC/N and kp>41% which is beneficial for the industrial production. The temperature aging properties of piezoelectric constant d33, planar electromechanical coupling factor kp, the elastic compliance constant S11E and the radial frequency constant Nd are also researched.

  16. Dependence of depolarization temperature on cation vacancies and lattice distortion for lead-free 74(Bi{sub 1/2}Na{sub 1/2})TiO{sub 3}-20.8(Bi{sub 1/2}K{sub 1/2})TiO{sub 3}-5.2BaTiO{sub 3} ferroelectric ceramics

    SciTech Connect

    Zhu Mankang; Hu Hancheng; Lei Na; Hou Yudong; Yan Hui

    2009-05-04

    In this paper, the off-morphotropic-phase-boundary 74(Bi{sub 1/2}Na{sub 1/2})TiO{sub 3}-20.8(Bi{sub 1/2}K{sub 1/2})TiO{sub 3}-5.2BaTiO{sub 3} ceramics were fabricated at different sintering temperatures. It was found out that as the sintering temperature increases, the volatilization of the A-site elements is aggravated, thus generating the oxygen vacancies; meanwhile, the tetragonality of the perovskite lattice reduces gradually. Besides, the temperature-dependent dielectric responses revealed that as the sintering temperature increases, the depolarization temperature T{sub d} decreases while the Curie-Weiss point T{sub C} increases. It is suggested that the lattice distortion, other than the oxygen vacancies, is the crucial factor in influencing the depolarization temperature.

  17. 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

  18. 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.

  19. Rare earths in lead-free oxyfluoride germanate glasses

    NASA Astrophysics Data System (ADS)

    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 Eu3+, Pr3+ and Er3+ ions were examined as a function of BaF2 concentration and several spectroscopic parameters for rare earths were determined. The ratio of integrated luminescence intensity of the 5D0 ? 7F2 transition to that of the 5D0 ? 7F1 transition of Eu3+ decrease significantly with increasing BaF2 content. The absorption (Er3+) and emission (Pr3+) 'hypersensitive transitions' of rare earths are shifted in direction to shorter wavelengths with increasing BaF2 content in glass composition. Emission spectra and their decays corresponding to the main 4I13/2 ? 4I15/2 laser transition of Er3+ were also analyzed. Quite long-lived NIR luminescence of Er3+ is observed for lead-free glass samples with low BaF2 concentration.

  20. 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.

  1. 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.

  2. Lead-free bearing alloys for engine applications

    NASA Astrophysics Data System (ADS)

    Ratke, Lorenz; gren, John; Ludwig, Andreas; Tonn, Babette; Grnsy, Lszl; Mathiesen, Ragnvald; Arnberg, Lars; Anger, Gerd; Reifenhuser, Bernd; Lauer, Michael; Garen, Rune; Gust, Edgar

    2005-10-01

    Recent developments to reduce the fuel consumption, emission and air pollution, size and weight of engines for automotive, truck, ship propulsion and electrical power generation lead to temperature and load conditions within the engines that cannot be borne by conventional bearings. Presently, only costly multilayer bearings with electroplated or sputtered surface coatings can cope with the load/speed combinations required. Ecological considerations in recent years led to a ban by the European Commission on the use of lead in cars a problem for the standard bronze-lead bearing material. This MAP project is therefore developing an aluminium-based lead-free bearing material with sufficient hardness, wear and friction properties and good corrosion resistance. Only alloys made of components immiscible in the molten state can meet the demanding requirements. Space experimentation plays a crucial role in optimising the cast microstructure for such applications.

  3. Fano resonance and dipolar relaxation in lead-free relaxors.

    PubMed

    Wang, D; Hlinka, J; Bokov, A A; Ye, Z-G; Ondrejkovic, P; Petzelt, J; Bellaiche, L

    2014-01-01

    Fano resonance is a phenomenon in which a discrete state interferes with a continuum of states and has been observed in many areas of science. Here, we report on the prediction of a Fano resonance in ferroelectric relaxors, whose properties are poorly understood: an ab initio molecular dynamic scheme reveals such resonance between the bare optical phonon mode of the Zr sublattice (the discrete state) and the bare optical phonon mode of the Ti sublattice (the continuum of states) in disordered lead-free Ba(Zr,Ti)O3. The microscopic origins of the discrete state and continuum of states are discussed in the context of relaxor properties. Furthermore, our simulations suggest that the T* characteristic temperature of relaxor is related to a hardening of the vibrational frequencies associated with fluctuation of the Ti sublattice. Finally, a terahertz relaxation mode reflecting reorientations of Ti dipoles and showing a thermally activated behaviour is predicted, in agreement with previous experiments. PMID:25369904

  4. 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 m. 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 (?b). The activation energy calculated from impedance and modulus data indicate that same types of charge carriers (oxygen vacancy movements) are responsible for conduction and relaxation.

  5. Viscoelectroelastic behavior of heterogeneous piezoelectric solids JiangYu Lia)

    E-print Network

    Li, Jiangyu

    been observed in bone,14 and in piezoelectric ceramic/polymer matrix composites.1517 In bone matrix and obtain closed form expressions for the effective complex electroelastic moduli. Numerical and relaxation in polycrystalline ceramics due to motion of 90 domain walls.912 Complex piezoelectric con

  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. 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.

  8. 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.

  9. FOREWORD: Focus on innovation in ceramics research in East Asia Focus on innovation in ceramics research in East Asia

    NASA Astrophysics Data System (ADS)

    Kato, Akio; Hishita, Shunichi; Osada, Minoru; Haneda, Hajime

    2010-10-01

    Ceramics, as broadly defined, include all materials other than organic substances and metals, either crystalline or amorphous. They have been used by humans since early history and have contributed considerably to improving the quality of our life. In most cases, however, high-temperature treatment is necessary to prepare ceramics. This burdens the environment and there is therefore a great need for new ceramics processing methods. Recent technologically advanced ceramics are often composed of nanocrystallites, which have great potential for innovation in terms of exploring practical applications of nanomaterials and, consequently, reducing the environmental load. The ceramics industry had long flourished in Asia, particularly in East Asia, and even today, this region is leading the development of related materials. In line with these traditions, Japanese and Korean ceramics societies have been co-sponsoring seminars on ceramics since the 1980s. Having become more international in scope and context, a series of these seminars is now known as the International Japan-Korea Seminar on Ceramics. This focus issue contains eight key articles presented at the 26th International Japan-Korea Seminar on Ceramics held on 24-26 November 2010 at the Tsukuba International Congress Center. In particular, Fabbri et al review electrode materials for protonic solid-oxide fuel cells, and Kamiya et al outline the present situation and future prospects for transparent transistors, particularly those based on amorphous In-Ga-Zn-O films. Eitel et al discuss the progress in engineering high-strain lead-free piezoelectric ceramics. Kim and Kumar review a simple processing method for producing porous ceramics using polysiloxane precursors, Kamiya and Iijima focus on surface modification and characterization of nanomaterials, and Wan et al briefly review the strategy of reducing lattice thermal conductivity of thermoelectric materials and propose new materials for thermoelectric devices. Aubert et al introduce a novel technique of synthesizing composite nanomaterials and Cross and coworkers characterize Pb(Zr,Ti)O3 (PZT) ferroelectric thin films co-doped with Bi and Fe to enhance PZT capacitor ferroelectric properties. These articles are closely related to the global environmental load and energy issues that require solutions in modern ceramics technology. We hope that this focus issue will help advance not only ceramics-related but also other fields of materials science.

  10. 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.

  11. 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

  12. 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.

  13. 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.

  14. Large effective-strain piezoelectric actuators using nested cellular architecture with exponential strain amplification mechanisms

    E-print Network

    Ueda, Jun

    Design and analysis of piezoelectric actuators having over 20% effective strain using an exponential strain amplification mechanism are presented in this paper. Piezoelectric ceramic material, such as lead zirconate titanate ...

  15. 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

  16. 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.

  17. 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

  18. Study of Lead Free Ferroelectric Films for New Solar Cells

    SciTech Connect

    Fasquelle, D.; Mascot, M.; Carru, J. C.; Hikam, M.; Iriani, Y.; Soegijono, B.

    2009-09-14

    We report on the deposition by a sol-gel process of Ba{sub 0.8}Sr{sub 0.2}TiO{sub 3} and Ba{sub 0.9}Sr{sub 0.1}TiO{sub 3} films on platinum coated silicon substrates. X-Ray diffraction patterns show that the films are (111) preferentially oriented. The surface morphology is smooth, without cracks and the grain size is about 50 nm as determined by AFM and SEM. The dielectric constant measured from 10{sup 2} to 10{sup 6} Hz decreases slightly and is around 400 at 10{sup 4} Hz. The losses are constant in a first approximation for a 1.5 {mu}m thick BST(80/20) film with a value of 0.03 at 10 kHz. The existence of an hysteresis cycle attests that the films, whatever their thickness, are in a ferroelectric state. Pyroelectric coefficients have been determined and the best figure of merit obtained on BST(90/10) at 293 K and 10 kHz is of 149 {mu}C/m{sup 3}/K. The best dielectric and pyroelectric properties (tg{delta} = 0.006 at 1 MHz, tunability = 30%, {gamma} = 340 {mu}C/m{sup 2}/K) were obtained on the 400 nm BST(90/10) film. Work is in progress to characterize the piezoelectric and photovoltaic properties of our BST films.

  19. 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.

  20. 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.

  1. 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.

  2. Design, fabrication, and properties of 2-2 connectivity cement/polymer based piezoelectric composites with varied piezoelectric phase distribution

    PubMed Central

    Dongyu, Xu; Xin, Cheng; Banerjee, Sourav; Shifeng, Huang

    2014-01-01

    The laminated 2-2 connectivity cement/polymer based piezoelectric composites with varied piezoelectric phase distribution were fabricated by employing Lead Zirconium Titanate ceramic as active phase, and mixture of cement powder, epoxy resin, and hardener as matrix phase with a mass proportion of 4:4:1. The dielectric, piezoelectric, and electromechanical coupling properties of the composites were studied. The composites with large total volume fraction of piezoelectric phase have large piezoelectric strain constant and relative permittivity, and the piezoelectric and dielectric properties of the composites are independent of the dimensional variations of the piezoelectric ceramic layer. The composites with small total volume fraction of piezoelectric phase have large piezoelectric voltage constant, but also large dielectric loss. The composite with gradually increased dimension of piezoelectric ceramic layer has the smallest dielectric loss, and that with the gradually increased dimension of matrix layer has the largest piezoelectric voltage constant. The novel piezoelectric composites show potential applications in fabricating ultrasonic transducers with varied surface vibration amplitude of the transducer. PMID:25565725

  3. Design, fabrication, and properties of 2-2 connectivity cement/polymer based piezoelectric composites with varied piezoelectric phase distribution

    NASA Astrophysics Data System (ADS)

    Dongyu, Xu; Xin, Cheng; Banerjee, Sourav; Shifeng, Huang

    2014-12-01

    The laminated 2-2 connectivity cement/polymer based piezoelectric composites with varied piezoelectric phase distribution were fabricated by employing Lead Zirconium Titanate ceramic as active phase, and mixture of cement powder, epoxy resin, and hardener as matrix phase with a mass proportion of 4:4:1. The dielectric, piezoelectric, and electromechanical coupling properties of the composites were studied. The composites with large total volume fraction of piezoelectric phase have large piezoelectric strain constant and relative permittivity, and the piezoelectric and dielectric properties of the composites are independent of the dimensional variations of the piezoelectric ceramic layer. The composites with small total volume fraction of piezoelectric phase have large piezoelectric voltage constant, but also large dielectric loss. The composite with gradually increased dimension of piezoelectric ceramic layer has the smallest dielectric loss, and that with the gradually increased dimension of matrix layer has the largest piezoelectric voltage constant. The novel piezoelectric composites show potential applications in fabricating ultrasonic transducers with varied surface vibration amplitude of the transducer.

  4. 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

  5. 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

  6. Numerical simulation of piezoelectric effect of bone under ultrasound irradiation

    NASA Astrophysics Data System (ADS)

    Hosokawa, Atsushi

    2015-07-01

    The piezoelectric effect of bone under ultrasound irradiation was numerically simulated using an elastic finite-difference time-domain method with piezoelectric constitutive equations (PE-FDTD method). First, to demonstrate the validity of the PE-FDTD method, the ultrasound propagation in piezoelectric ceramics was simulated and then compared with the experimental results. The simulated and experimental waveforms propagating through the ceramics were in good agreement. Next, the piezoelectric effect of human cortical bone on the ultrasound propagation was investigated by PE-FDTD simulation. The simulated result showed that the difference between the waveforms propagating through the bone without and with piezoelectricity was negligible. Finally, the spatial distributions of the electric fields in a human femur induced by ultrasound irradiation were simulated. The electric fields were changed by a bone fracture, which depended on piezoelectric anisotropy. In conclusion, the PE-FDTD method is considered to be useful for investigating the piezoelectric effect of bone.

  7. Room temperature nonlinear magnetoelectric effect in lead-free and Nb-doped AlFeO{sub 3} compositions

    SciTech Connect

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

  8. 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.

  9. Lead-free KNbO ferroelectric nanorod based flexible nanogenerators and capacitors

    E-print Network

    Wang, Zhong L.

    Lead-free KNbO 3 ferroelectric nanorod based flexible nanogenerators and capacitors This article.1088/0957-4484/23/37/375401 Lead-free KNbO3 ferroelectric nanorod based flexible nanogenerators and capacitors Jong Hoon Jung1 as well as high-k capacitor applications by performing electrical poling and further optimizing the device

  10. 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

  11. 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.

  12. Piezoelectric properties and thermal stability of Ca0.92(Li,Ce)0.04Bi2Nb2- x W x O9 high-temperature ceramics

    NASA Astrophysics Data System (ADS)

    Wang, Yadan; Wu, Jiagang; Peng, Zhihang; Chen, Qiang; Xin, Deqiong; Xiao, Dingquan; Zhu, Jianguo

    2015-04-01

    Ca0.92(Li,Ce)0.04Bi2Nb2- x W x O9 ( x = 0.01-0.06) high-temperature piezoceramics were prepared by a conventional solid-state sintered method, and effects of W content on their piezoelectric properties were studied. All samples possess a pure Aurivillius-type structure, showing that Li, Ce, and W dopants have well diffused into the CaBi2Nb2O9 lattice to form a solid solution. The doping with W slightly decreases the Curie temperature ( T C) of the ceramics. In addition, the excellent electrical properties (e.g., d 33 ~ 16.1 pC/N, k p ~ 9.58 %, Q m ~ 4,767) and a high Curie temperature (e.g., T c ~ 925 C) are simultaneously obtained in the ceramics with x = 0.04, together with an enhanced thermal stability of <900 C. As a result, the investigated material system provides the promising potential applications in ultra-high-temperature environments.

  13. Field-enhanced piezoelectric deformation during the high temperature/low temperature rhombohedral (FERh/FERL) phase transformation for tin modified lead zirconate titanate ceramics

    NASA Astrophysics Data System (ADS)

    Yang, Pin; Moore, Roger H.; Burns, George R.

    2002-06-01

    An unusual field-enhanced piezoelectric deformation near the FERH/FERL structural phase transformation was observed in a tin modified lead zirconate titanate solid solution. In addition to the typical field-induced domain reorientation and the piezoelectric strain, this additional field-enhanced deformation only observed near the phase transformation increases linearly with external electric field strength. A 78% increase in field-enhanced strain was observed at a field strength of 32 kV/cm. Comparison of the dielectric susceptibility at low and high field conditions suggests that the observed unusual behavior is created by a field-induced lattice softening during the structural phase transformation. Experimental observations on the field-induced softening phenomena are reported.

  14. 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.

  15. Effect of sintering temperature on the electromechanical properties of 0.945Bi0.5Na0.5TiO3-0.055BaZrO3 ceramics

    NASA Astrophysics Data System (ADS)

    Rahman, Jamil Ur; Hussain, Ali; Maqbool, Adnan; Malik, Rizwan Ahmed; Kim, Min Su; Kim, Myong Ho

    2015-04-01

    In this work, lead-free 0.945B0.5N0.5TiO3-0.055BaZrO3 (BNT-BZ) ceramics were synthesized by using conventional solid-state reaction method and the effect of different sintering temperatures (1145-1200 C) on its structure and electromechanical properties were investigated. XRD patterns revealed single a phase-perovskite structure for all samples sintered at different temperatures. An optimum sintering temperature enhanced densification, promoted grain growth, and improve the dielectric and piezoelectric properties. However, at low (1145 C) and high (1200 C) sintering temperatures, the BNT-BZ ceramics showed inferior electromechanical properties. BNT-BZ ceramics sintered at an optimum temperature (1175 C) showed an enhanced strain (0.39%) response at an applied electric field of 7 kV/mm with a high dynamic piezoelectric coefficient ( d 33* = 557 pm/V). These results can be attributed to the high density of the BNT-BZ ceramics sintered at 1175 C.

  16. 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.

  17. 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.

  18. DOI: 10.1002/adma.200601162 Nanowire Piezoelectric Nanogenerators on Plastic Substrates as

    E-print Network

    Wang, Zhong L.

    current generation. This is the principle behind piezoelectric nanogenerators. The ceramicDOI: 10.1002/adma.200601162 Nanowire Piezoelectric Nanogenerators on Plastic Substrates as Flexible a power source, such as electrochemical cells[8] or piezoelectric,[9] thermoelectric,[10] and pyroelectric

  19. 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.

  20. Analysis of microstructural elds in heterogeneous piezoelectric solids

    E-print Network

    Li, Jiangyu

    elds. The general theory is applicable to both polycrystalline ceramics as well as matrix-based composites. After the general development, the theory is applied to multiphase matrix-based piezoelectric composites bers are often embedded in a polymer matrix to form a piezoelectric composite. At this scale

  1. Study of Thermo-Electro-Mechnical Coupling in Functionally Graded Metal-Ceramic Composites

    E-print Network

    Doshi, Sukanya 1988-

    2012-12-10

    Piezoelectric actuators have been developed in various forms ranging from discrete layered composites to functionally graded composites. These composite actuators are usually made up of differentially poled piezoelectric ceramics. This study...

  2. 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.

  3. 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

  4. Performance of Lead-Free versus Lead-Based Hunting Ammunition in Ballistic Soap

    PubMed Central

    Gremse, Felix; Krone, Oliver; Thamm, Mirko; Kiessling, Fabian; Tolba, Ren Hany; Rieger, Siegfried; Gremse, Carl

    2014-01-01

    Background Lead-free hunting bullets are an alternative to lead-containing bullets which cause health risks for humans and endangered scavenging raptors through lead ingestion. However, doubts concerning the effectiveness of lead-free hunting bullets hinder the wide-spread acceptance in the hunting and wildlife management community. Methods We performed terminal ballistic experiments under standardized conditions with ballistic soap as surrogate for game animal tissue to characterize dimensionally stable, partially fragmenting, and deforming lead-free bullets and one commonly used lead-containing bullet. The permanent cavities created in soap blocks are used as a measure for the potential wound damage. The soap blocks were imaged using computed tomography to assess the volume and shape of the cavity and the number of fragments. Shots were performed at different impact speeds, covering a realistic shooting range. Using 3D image segmentation, cavity volume, metal fragment count, deflection angle, and depth of maximum damage were determined. Shots were repeated to investigate the reproducibility of ballistic soap experiments. Results All bullets showed an increasing cavity volume with increasing deposited energy. The dimensionally stable and fragmenting lead-free bullets achieved a constant conversion ratio while the deforming copper and lead-containing bullets showed a ratio, which increases linearly with the total deposited energy. The lead-containing bullet created hundreds of fragments and significantly more fragments than the lead-free bullets. The deflection angle was significantly higher for the dimensionally stable bullet due to its tumbling behavior and was similarly low for the other bullets. The deforming bullets achieved higher reproducibility than the fragmenting and dimensionally stable bullets. Conclusion The deforming lead-free bullet closely resembled the deforming lead-containing bullet in terms of energy conversion, deflection angle, cavity shape, and reproducibility, showing that similar terminal ballistic behavior can be achieved. Furthermore, the volumetric image processing allowed superior analysis compared to methods that involve cutting of the soap blocks. PMID:25029572

  5. 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 1150C 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.

  6. Lead-free precussion primer mixes based on metastable interstitial composite (MIC) technology

    DOEpatents

    Dixon, George P. (Alexandria, VA); Martin, Joe A. (Espanola, NM); Thompson, Don (Ridgecrest, CA)

    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.

  7. 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.

  8. Semiconductor/relaxor 0-3 type composites without thermal depolarization in Bi0.5Na0.5TiO3-based lead-free piezoceramics

    NASA Astrophysics Data System (ADS)

    Zhang, Ji; Pan, Zhao; Guo, Fei-Fei; Liu, Wen-Chao; Ning, Huanpo; Chen, Y. B.; Lu, Ming-Hui; Yang, Bin; Chen, Jun; Zhang, Shan-Tao; Xing, Xianran; Rdel, Jrgen; Cao, Wenwu; Chen, Yan-Feng

    2015-03-01

    Commercial lead-based piezoelectric materials raised worldwide environmental concerns in the past decade. Bi0.5Na0.5TiO3-based solid solution is among the most promising lead-free piezoelectric candidates; however, depolarization of these solid solutions is a longstanding obstacle for their practical applications. Here we use a strategy to defer the thermal depolarization, even render depolarization-free Bi0.5Na0.5TiO3-based 0-3-type composites. This is achieved by introducing semiconducting ZnO particles into the relaxor ferroelectric 0.94Bi0.5Na0.5TiO3-0.06BaTiO3 matrix. The depolarization temperature increases with increasing ZnO concentration until depolarization disappears at 30 mol% ZnO. The semiconducting nature of ZnO provides charges to partially compensate the ferroelectric depolarization field. These results not only pave the way for applications of Bi0.5Na0.5TiO3-based piezoceramics, but also have great impact on the understanding of the mechanism of depolarization so as to provide a new design to optimize the performance of lead-free piezoelectrics.

  9. Micromachined Piezoelectric Microspeaker

    NASA Astrophysics Data System (ADS)

    Yi, Seung Hwan; Kim, Eun Sok

    2005-06-01

    A diaphragm-based piezoelectric microspeaker is fabricated on a heavily compressive silicon-nitride film, and is compared to commercial speakers. The largest sound pressure level (SPL) produced by the fabricated microspeaker is 92 dB (when measured 2 mm away from the microspeaker in open field) at around 3 kHz for 6 Vpeak-to-peak input. The microspeaker produces a comparable sound output as a commercial piezo-ceramic and electro-dynamic speaker used in current cellular phones. The keys to this success are as follows: (1) the usage of a diaphragm that has a very high compressive residual stress, high enough to cause the diaphragm to be wrinkled and (2) the usage of high quality ZnO film deposited by two-step deposition technique.

  10. Concurrent electromigration and creep in lead-free solder Matt Pharr,1

    E-print Network

    Suo, Zhigang

    Concurrent electromigration and creep in lead-free solder Matt Pharr,1 Kejie Zhao,1 Zhigang Suo,1,a online 28 October 2011) When electric current flows in a solder bump, electromigration generates stress electromigra- tion in solder bumps is much smaller than in any other com- ponents.1 Electromigration can cause

  11. Intermetallic Growth Studies on Sn-Ag-Cu Lead-Free Solder Joints

    E-print Network

    Zhou, Wei

    Intermetallic Growth Studies on Sn-Ag-Cu Lead-Free Solder Joints JOHN H.L. PANG,1,2 LUHUA XU,1 X (IMC) growth behavior plays an important role in solder joint reliability of electronic packaging solders and nickel/gold (Ni/Au) surface finish on BGA solder joint specimen is reported. Digital imaging

  12. The Influence of Sn Orientation on the Electromigration of Idealized Lead-free Interconnects

    E-print Network

    Linares, Xioranny

    2015-01-01

    solder joints, has made them susceptible to electromigration damage, which poses a major reliabilityreliability of new electronic devices by studying electromigration phenomena in new lead free solder joints.solders are being replaced by Pb-free solders in electronic devices, the reliability of solder joints

  13. 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...

  14. How to Identify Lead-Free Certification Marks for Drinking Water System & Plumbing Materials

    EPA Science Inventory

    In 2011, Congress passed the Reduction of Lead in Drinking Water Act, which effectively reduces the lead content allowed in material used for potable water plumbing. The Act, which will go into effect on January 4, 2014, changes the definition of lead-free by reducing allowed...

  15. 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.

  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. Thick lead-free ferroelectric films with high Curie temperatures through nanocomposite-

    E-print Network

    Eom, Chang Beom

    Thick lead-free ferroelectric films with high Curie temperatures through nanocomposite- induced alternative, BaTiO3, is non-toxic and has excellent ferro- electric properties, but its Curie temperature of 130 88888C is too low to be practical3 . Strain has been used to enhance the Curie temperature of Ba

  18. Fracture Behavior and Characterization of Lead-Free Brass Alloys for Machining Applications

    NASA Astrophysics Data System (ADS)

    Toulfatzis, Anagnostis I.; Pantazopoulos, George A.; Paipetis, Alkiviadis S.

    2014-09-01

    The stricter environmental, health, and safety regulations address the harmful effects of lead and provide the driving force for the development of lead-free brass alloys. Conventional leaded brass rods are widely used in several manufacturing sectors (i.e., fabrication of hydraulic components, fittings, valves, etc.) due to their superior workability in extrusion and drawing as well as their superior machinability. As machinability performance involves shear and dynamic fracture processes evolved under high strain-rate conditions, the understanding of the mechanical behavior/microstructure interaction is critical in order to successfully tailor candidate lead-free alloys for improved machinability without compromising the reliability of manufactured components. In this work, the mechanical behavior under static and dynamic loading of three lead-free brass alloys (CW510L-CW511L-C27450) in comparison to a conventional leaded brass alloy (CW614N) was studied. The fractographic evaluation of the texture of conjugate fracture surfaces was performed to identify the involved fracture mechanisms and their relation to the alloy microstructure. It was shown that the CW510L lead-free brass alloy is a potential candidate in replacing conventional CW614N leaded brass, combining high tensile strength and fracture toughness, due to the prevalence of the ?-intermetallic phase in the alloy microstructure.

  19. Lead-free halide perovskite solar cells with high photocurrents realized through vacancy modulation.

    PubMed

    Kumar, Mulmudi Hemant; Dharani, Sabba; Leong, Wei Lin; Boix, Pablo P; Prabhakar, Rajiv Ramanujam; Baikie, Tom; Shi, Chen; Ding, Hong; Ramesh, Ramamoorthy; Asta, Mark; Graetzel, Michael; Mhaisalkar, Subodh G; Mathews, Nripan

    2014-11-01

    Lead free perovskite solar cells based on a CsSnI3 light absorber with a spectral response from 950 nm is demonstrated. The high photocurrents noted in the system are a consequence of SnF2 addition which reduces defect concentrations and hence the background charge carrier density. PMID:25212785

  20. Polarization alignment, phase transition, and piezoelectricity development in polycrystalline 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3

    NASA Astrophysics Data System (ADS)

    Guo, Hanzheng; Voas, Brian K.; Zhang, Shujun; Zhou, Chao; Ren, Xiaobing; Beckman, Scott P.; Tan, Xiaoli

    2014-07-01

    The microstructural origin of the exceptionally high piezoelectric response of polycrystalline 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 is investigated using in situ transmission electron microscopy, in addition to a wide variety of bulk measurements and first-principles calculations. A direct correlation is established relating a domain wall-free state to the ultrahigh piezoelectric d33 coefficient in this BaTiO3-based composition. The results suggest that the unique single-domain state formed during electrical poling is a result of a structural transition from coexistent rhombohedral and tetragonal phases to an orthorhombic phase that has an anomalously low elastic modulus. First-principles calculations indicate that incorporating Ca2+ and Zr4+ into BaTiO3 reduces the differences in structure and energy of the variant perovskite phases, and 0.5Ba (Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 is identified as unique because the variant phases become almost indistinguishable. The structural instability and elastic softening observed here are responsible for the excellent piezoelectric properties of this lead-free ceramic.

  1. 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.

  2. Piezoelectric trace vapor calibrator

    SciTech Connect

    Verkouteren, R. Michael; Gillen, Greg; Taylor, David W.

    2006-08-15

    The design and performance of a vapor generator for calibration and testing of trace chemical sensors are described. The device utilizes piezoelectric ink-jet nozzles to dispense and vaporize precisely known amounts of analyte solutions as monodisperse droplets onto a hot ceramic surface, where the generated vapors are mixed with air before exiting the device. Injected droplets are monitored by microscope with strobed illumination, and the reproducibility of droplet volumes is optimized by adjustment of piezoelectric wave form parameters. Complete vaporization of the droplets occurs only across a 10 deg. C window within the transition boiling regime of the solvent, and the minimum and maximum rates of trace analyte that may be injected and evaporated are determined by thermodynamic principles and empirical observations of droplet formation and stability. By varying solution concentrations, droplet injection rates, air flow, and the number of active nozzles, the system is designed to deliver--on demand--continuous vapor concentrations across more than six orders of magnitude (nominally 290 fg/l to 1.05 {mu}g/l). Vapor pulses containing femtogram to microgram quantities of analyte may also be generated. Calibrated ranges of three explosive vapors at ng/l levels were generated by the device and directly measured by ion mobility spectrometry (IMS). These data demonstrate expected linear trends within the limited working range of the IMS detector and also exhibit subtle nonlinear behavior from the IMS measurement process.

  3. Abstract--Piezoelectricity is an ability of some materials to generate an electric potential in response to applied mechanical

    E-print Network

    Ha, Dong S.

    Abstract--Piezoelectricity is an ability of some materials to generate an electric potential, PZT ceramics I. INTRODUCTION Piezoelectricity is an ability to generate an electric potential that demonstrate the direct piezoelectric effect, which is the generation of electricity upon applied mechanical

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. Thermal model for piezoelectric transducers (L).

    PubMed

    Butler, John L; Butler, Alexander L; Butler, Stephen C

    2012-10-01

    A lumped parameter equivalent circuit basis for calculating and allocating heat power sources in a transducer is presented along with experimental results. The simple model allows heat power calculations at resonance based on readily attainable parameters for transducers with uniform fields. Measured and finite element analysis of steady state thermal results are compared for the monopole mode of the single crystal driven modal transducer projector. The model serves as a physical and computational aid in the evaluation of piezoelectric transducer heating and may be used for evaluating highly coupled single crystal as well as ceramic piezoelectric transducers. PMID:23039410

  9. Proceedings of the 2007 Aging Aircraft Conference Cost Model for Assessing the Transition to Lead-Free Electronics

    E-print Network

    Sandborn, Peter

    Proceedings of the 2007 Aging Aircraft Conference Cost Model for Assessing the Transition to Lead the cost ramifications of the transition from tin- lead to lead-free electronic parts. All tin-lead, all lead-free and mixed assembly approaches are considered. The model makes basic assumptions of a fixed

  10. 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.

  11. 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 1200C to 920C 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 ( ? 33 T / ? 0 = 2904) and low dielectric loss (tan ? = 0.0166) were obtained in this work.

  12. 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.

  13. An exact analysis of a rectangular plate piezoelectric generator.

    PubMed

    Yang, Jiashi; Chen, Ziguang; Hu, Yuantai

    2007-01-01

    We study thickness-twist vibration of a finite, piezoelectric plate of polarized ceramics or 6-mm crystals driven by surface mechanical loads. An exact solution from the three-dimensional equations of piezoelectricity is obtained. The plate is properly electroded and connected to a circuit such that an electric output is generated. The structure analyzed represents a piezoelectric generator for converting mechanical energy to electrical energy. Analytical expressions for the output voltage, current, power, efficiency, and power density are given. The basic behaviors of the generator are shown by numerical results. PMID:17225813

  14. VOLTAGE-TUNABLE PIEZOELECTRICALLY-TRANSDUCED SINGLE-CRYSTAL SILICON RESONATORS ON SOI SUBSTRATE

    E-print Network

    Ayazi, Farrokh

    VOLTAGE-TUNABLE PIEZOELECTRICALLY-TRANSDUCED SINGLE-CRYSTAL SILICON RESONATORS ON SOI SUBSTRATE) resonators that are piezoelectrically actuated and sensed, and have voltage-tunable center frequencies blocks for on-chip integrated filter and frequency references to replace bulky, off-chip ceramic and SAW

  15. 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.

  16. Evaluation of Diffusion Barrier Between Lead-Free Solder Systems and Thermoelectric Materials

    NASA Astrophysics Data System (ADS)

    Lin, T. Y.; Liao, C. N.; Wu, Albert T.

    2012-01-01

    The intermetallic compound SnTe rapidly formed at interfaces between p-type bismuth telluride (Bi0.5Sb1.5Te3) thermoelectric materials and lead-free solders. The intermetallic compound influences the mechanical properties of the joints and the reliability of the thermoelectric modules. Various lead-free solder alloys, Sn-3.5Ag, Sn-3Ag-0.5Cu, Sn-0.7Cu, and Sn-2.5Ag-2Ni, were used to investigate the interfacial reactions. The results thus obtained show that Ag and Cu preferentially diffused into the Te-rich phase in Bi0.5Sb1.5Te3, so layers of Ag-Te and Cu-Te compounds could not form an effective diffusion barrier. Electroless nickel-phosphorus was plated at the interfaces to serve as a diffusion barrier, and the (Cu,Ni)6Sn5 compound formed instead of SnTe. Furthermore, the intermetallic compound NiTe formed between nickel- phosphorus and Bi0.5Sb1.5Te3 and also served as a diffusion barrier. A plot of thickness as a function of annealing time yielded the growth kinetics of the intermetallic compounds in the thermoelectric material systems. The activation energy for the growth of the NiTe intermetallic compound is 111 kJ/mol.

  17. Evaluation of Bulk Mechanical Properties of Selected Lead-Free Solders in Tension and in Shear

    NASA Astrophysics Data System (ADS)

    Devaki Rani, S.; Murthy, G. S.

    2013-08-01

    Lead-free solders are fast emerging as better alternatives to Sn-Pb solders. The reliability of a soldered joint to withstand imposed stresses in an assembly is decided by its mechanical properties. The present work is about the investigation of tensile and shear properties of four binary eutectic alloys Sn-3.5Ag, Sn-58Bi, Sn-0.7Cu, Sn-9Zn and a ternary alloy Sn-57Bi-1.3Zn in comparison with conventional Sn-38Pb alloy. It is observed that the lead-free solders have better mechanical properties than the latter. SEM studies of tensile and shear fracture show ductile dimples circular in tension and parabolic in shear modes supporting the mechanical behavior of the alloys investigated. Eutectic alloys Sn-Ag, Sn-Zn, and Sn-Cu form potential substitutes for Sn-Pb for electronic interconnects exposed to high temperatures, while Sn-Bi and Sn-Bi-Zn are attractive alternatives in addressing the need of lower processing temperatures in printed circuit boards and other applications.

  18. Current Problems and Possible Solutions in High-Temperature Lead-Free Soldering

    NASA Astrophysics Data System (ADS)

    Kroupa, Ales; Andersson, Dag; Hoo, Nick; Pearce, Jeremy; Watson, Andrew; Dinsdale, Alan; Mucklejohn, Stuart

    2012-05-01

    The substitution of lead in the electronics industry is one of the key issues in the current drive towards ecological manufacturing. Legislation has already banned the use of lead in solders for mainstream applications ( T M ? 220 C), but the use of lead in the solders for high-temperature applications (>85% lead, T M ? 250-350 C) is still exempt in RoHS2. The search for proper substitutes has been ongoing among solder manufacturers only for a decade without finding a viable low cost alternative and is the subject of intensive research. This article tries to map the current situation in the field of high-temperature lead-free soldering, presenting a short review of current legislation, requirements for substitute alloys, and finally it describes some existing solutions both in the field of promising new materials and new technologies. Currently, there is no drop-in replacement for lead-containing solders and therefore both the new materials and the new technologies may be viable solutions for production of reliable lead-free joints for high-temperature applications.

  19. Study on Dynamic Failure Model of Lead-Free Solders Using Shpb Techniques

    NASA Astrophysics Data System (ADS)

    Niu, Xiaoyan; Yuan, Guozheng; Li, Zhigang; Shu, Xuefeng

    The dynamic compressive properties of 96.3Sn3Ag0.7Cu and 99.3Sn0.7Cu solders were studied by means of a split Hopkinson pressure bar at strain rates ranging from 500 to 2000 s-1. Tests were conducted at room temperature and under uniaxial compressive conditions. Eutectic SnPb solders were used as the reference. From the data of tests, it was found that yield strength and flow stress increased remarkably with the increase of strain rate. On logarithmic scales, the yield strength increased linearly with strain rate. These lead-free solders revealed certain visco-plastic behavior and strain rate sensitivity, which predicted using Johnson-Cook material model. Related parameters in the model were determined from the experiment. Compared with the typical Pb-containing solder Sn63Pb37, these lead-free solders showed some fine properties and could substitute some Pb-containing solder alloys in microelectronic components packaging and interconnects.

  20. 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.

  1. 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.

  2. 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.

  3. Lead-free solid-state organic-inorganic halide perovskite solar cells

    NASA Astrophysics Data System (ADS)

    Hao, Feng; Stoumpos, Constantinos C.; Cao, Duyen Hanh; Chang, Robert P. H.; Kanatzidis, Mercouri G.

    2014-06-01

    Lead-free solution-processed solid-state photovoltaic devices based on methylammonium tin iodide (CH3NH3SnI3) perovskite semiconductor as the light harvester are reported. Featuring an optical bandgap of 1.3 eV, the CH3NH3SnI3 perovskite material can be incorporated into devices with the organic hole-transport layer spiro-OMeTAD and show an absorption onset at 950 nm, which is significantly redshifted compared with the benchmark CH3NH3PbI3 counterpart (1.55 eV). Bandgap engineering was implemented by chemical substitution in the form of CH3NH3SnI3-xBrx solid solutions, which can be controllably tuned to cover much of the visible spectrum, thus enabling the realization of lead-free solar cells with an initial power conversion efficiency of 5.73% under simulated full sunlight. Further efficiency enhancements are expected following optimization and a better fundamental understanding of the internal electron dynamics and corresponding interfacial engineering. The reported CH3NH3SnI3-xBrx perovskite solar cells represent a step towards the realization of low-cost, environmentally friendly solid-state solar cells.

  4. Dielectric and piezoelectric properties of S001< fiber-textured 0.675Pb,,Mg13Nb23...O3 0.325PbTiO3 ceramics

    E-print Network

    Messing, Gary L.

    Dielectric and piezoelectric properties of S001 to the application of the domain engineering concept for perovskite ferroelectrics which have a rhombohedral a high degree of grain orien- tation texture possess directionally dependent dielectric, pyroelectric

  5. 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.

  6. 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.

  7. Piezoelectricity and local structural distortions in (Na{sub 0.5}Bi{sub 0.5}){sub 1-x}Sr{sub x}TiO{sub 3}-Bi{sub 12}TiO{sub 20} flexoelectric-type polar ceramics

    SciTech Connect

    Wang, L. H.; Zhao, M. L.; Wang, C. L.; Wang, J.; Kuai, W. J.; Tao, X. T.

    2012-08-06

    We have previously described sintered Na{sub 0.5}Bi{sub 0.5}TiO{sub 3}-Bi{sub 12}TiO{sub 20} composites as flexoelectric-type polar ceramics because they have a net macroscopic flexoelectric polarization. Here, we report on the universal existence of the macroscopic flexoelectric polarization in the (Na{sub 0.5}Bi{sub 0.5}){sub 1-x}Sr{sub x}TiO{sub 3}-Bi{sub 12}TiO{sub 20} system, in which enhanced piezoelectricity is observed. By combining Raman spectroscopy and x-ray photoelectron spectroscopy techniques, we have identified the local flexoelectric polarization as distorted BiO{sub 5} polyhedra and TiO{sub 6} octahedra in the SrTiO{sub 3}-Bi{sub 12}TiO{sub 20} ceramic. The macroscopic polarization may be due to the partial alignment of these distorted units located within the grain boundary amorphous phases. Bi{sub 12}TiO{sub 20} could have an important role in these flexoelectric-type polar ceramics.

  8. 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.

  9. 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.

  10. Piezoelectric drive circuit

    DOEpatents

    Treu, Jr., Charles A. (Raymore, MO)

    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.

  11. "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.

  12. 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.

  13. Bonding nature of rare-earth-containing lead-free solders

    NASA Astrophysics Data System (ADS)

    Ramirez, Ainissa G.; Mavoori, Hareesh; Jin, Sungho

    2002-01-01

    The ability of rare-earth-containing lead-free solders to wet and bond to silica was investigated. Small additions of Lu (0.5-2 wt. %) added to eutectic Sn-Ag or Au-Sn solder render it directly solderable to a silicon oxide surface. The bonding is attributed to the migration of the rare-earth element to the solder-silica interface for chemical reaction and the creation of an interfacial layer that contains a rare-earth oxide. It was found that additions of rare-earth materials did not significantly modify the solidification microstructure or the melting point. Such oxide-bondable solders can be useful for assembly of various optical communication devices.

  14. 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.

  15. 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

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

    PubMed Central

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

    2015-01-01

    We introduce a novel lead-free ferroelectric thin film (1-x)BaTiO3-xBa(Cu1/3Nb2/3)O3 (x = 0.025) (BT-BCN) integrated on to HfO2 buffered Si for non-volatile memory (NVM) applications. Piezoelectric force microscopy (PFM), x-ray diffraction, and high resolution transmission electron microscopy were employed to establish the ferroelectricity in BT-BCN thin films. PFM study reveals that the domains reversal occurs with 180 phase change by applying external voltage, demonstrating its effectiveness for NVM device applications. X-ray photoelectron microscopy was used to investigate the band alignments between atomic layer deposited HfO2 and pulsed laser deposited BT-BCN films. Programming and erasing operations were explained on the basis of band-alignments. The structure offers large memory window, low leakage current, and high and low capacitance values that were easily distinguishable even after ~106?s, indicating strong charge storage potential. This study explains a new approach towards the realization of ferroelectric based memory devices integrated on Si platform and also opens up a new possibility to embed the system within current complementary metal-oxide-semiconductor processing technology. PMID:25683062

  17. 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.

  18. Accepted for publication Microelectronics Reliability February 1, 2014 Assessing the value of a lead-free solder control plan using cost-

    E-print Network

    Sandborn, Peter

    of a lead-free solder control plan using cost- based FMEA Edwin Lilliea , Peter Sandborna , David Humphreyb of lead-free solder for the assembly of electronic systems in critical applications that previously used tin-lead solder. A case study of the lead-free implementation of a power supply demonstrates

  19. 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.

  20. Polarity effect of electromigration on mechanical properties of lead-free solder joints

    NASA Astrophysics Data System (ADS)

    Ren, Fei

    The trend of electronic packaging is to package the chips and the associated interconnections in a compact way that allows high speed operation; that allows for sufficient heat removal; that can withstand the thermal cycling associated with the turning on and turning off of the circuits; and that protects the circuits from environmental attack. These goals require that flip chip solder joints have higher resistance to electromigration, stronger mechanical property to sustain thermal mechanical stress, and are lead-free materials to satisfy environment and health concern. With lots of work on chemical reaction, electromigration and mechanical study in flip chip solder joints, however, the interaction between different driving forces is still little known. As a matter of fact, the combination study of chemical, electrical and mechanical is more and more significant to the understanding of the behavior of flip chip solder joints. In this dissertation, I developed one dimensional Cu (wire)-eutectic SnAgCu(ball)-Cu(wire) structure to investigate the interaction between electrical and mechanical force in lead-free solder joints. Electromigration was first conducted. The mechanical behaviors of solder joints before, after, and during electromigration were examined. Electrical current and mechanical stress were applied either in serial or in parallel to the solder joints. Tensile, creep, and drop tests, combined with different electrical current densities (15x10 3A/cm2) and different stressing time (3144 hours), have been performed to study the effect of electromigration on the mechanical behavior of solder joints. Nano-indentation test was conducted to study the localized mechanical property of IMC at both interfaces in nanometer scale. Fracture images help analyze the failure mechanism of solder joints driven by both electrical and mechanical forces. The combination study shows a strain build-up during electromigration. Furthermore, a ductile-to-brittle transition in flip chip solder joints induced by electromigration is observed, in which the fracture position migrates from the middle to the cathode interface of the joint with increasing current density and time. The transition is explained by the polarity effect of electromigration, particular due to the accumulation of vacancies at the cathode interface.

  1. The elastic and piezoelectric properties of tungsten bronze ferroelectric crystals ,,Sr0.7Ba0.3...2NaNb5O15 and ,,Sr0.3Ba0.7...2NaNb5O15

    E-print Network

    Cao, Wenwu

    perovskite structure ferro- electrics due to their superior dielectric, piezoelectric, pyro- electric that these single crystals have larger dielectric constant and good piezoelectric property compared to other known lead-free perovskite ferroelectric crystals. The measurements show that the SBNN70 has larger

  2. 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.

  3. 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.

  4. 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.

  5. Mechanical Properties of Lead-Free Solder Joints Under High-Speed Shear Impact Loading

    NASA Astrophysics Data System (ADS)

    Nguyen, Van Luong; Kim, Ho-Kyung

    2014-09-01

    In this study we expanded on recently reported research by using a modified miniature Charpy impact-testing system to investigate the shear deformation behavior of Sn-3.0Ag-0.5Cu lead-free solder joints at high strain rates ranging from 1.1 103 s-1 to 5.5 103 s-1. The experimental results revealed that the maximum shear strength of the solder joint decreased with increasing load speed in the ranges tested in this study. For solder joints tested at a shear speed exceeding 1 m/s, corresponding to an approximate strain rate that exceeds 1950 s-1, the brittle fracture mode is the main failure mode, whereas lower strain rates result in a ductile-to-brittle transition in the fracture surfaces of solder joints. In addition, the mode II stress intensity factor (K II) used to evaluate the fracture toughness (K C) of an interfacial intermetallic compound layer between Sn-3.0Ag-0.5Cu solder and the toughness of copper substrate was found to decrease from 1.63 MPa m0.5 to 0.97 MPa m0.5 in the speed range tested here.

  6. Mechanical Properties of Lead-Free Solder Joints Under High-Speed Shear Impact Loading

    NASA Astrophysics Data System (ADS)

    Nguyen, Van Luong; Kim, Ho-Kyung

    2014-11-01

    In this study we expanded on recently reported research by using a modified miniature Charpy impact-testing system to investigate the shear deformation behavior of Sn-3.0Ag-0.5Cu lead-free solder joints at high strain rates ranging from 1.1 103 s-1 to 5.5 103 s-1. The experimental results revealed that the maximum shear strength of the solder joint decreased with increasing load speed in the ranges tested in this study. For solder joints tested at a shear speed exceeding 1 m/s, corresponding to an approximate strain rate that exceeds 1950 s-1, the brittle fracture mode is the main failure mode, whereas lower strain rates result in a ductile-to-brittle transition in the fracture surfaces of solder joints. In addition, the mode II stress intensity factor ( K II) used to evaluate the fracture toughness ( K C) of an interfacial intermetallic compound layer between Sn-3.0Ag-0.5Cu solder and the toughness of copper substrate was found to decrease from 1.63 MPa m0.5 to 0.97 MPa m0.5 in the speed range tested here.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. The Measurement of Thermal Conductivity Variation with Temperature for Sn-Based Lead-Free Binary Solders

    NASA Astrophysics Data System (ADS)

    Demir, Mustafa; Aksz, Sezen; ztrk, Esra; Mara?l?, Necmettin

    2014-10-01

    The variations of thermal conductivity with temperature in the Sn-based lead-free binary solders, Sn-10 wt pct X (X = Ag, In, Bi, Cu, Sb, Zn), were measured by using the linear heat flow apparatus. The thermal conductivities of Sn-based lead-free solders at their melting temperature were obtained from graphs of thermal conductivity variation with temperature. The variations of electrical conductivity with temperature for same solders were also determined from the Wiedemann-Franz (W-F) equation by using the measured values of thermal conductivity.

  12. Generating characteristics of an eye-shaped piezoelectric harvester

    NASA Astrophysics Data System (ADS)

    Ha, Yong-Woo; Jeong, Seong-Su; Kim, Na-Lee; Cheon, Seong-Kyu; Park, Tae-Gone; Song, Jae-Sung

    2014-07-01

    In this paper, a newly designed piezoelectric harvester which generates electricity by using tensions on the device is proposed. The device is named as an eye-shaped harvester. The eye-shaped harvester consists of a rectangular ceramic and two elastic body plates are attached to each surface of the ceramic. If tensions are given at both ends of the elastic body, the tensions are changed to pressures on the ceramic through a form change of the elastic body and the piezoelectric effect occurs at the ceramic to generate electricity. Because of the structure of this eye-shaped generator if can be easily in various places where tensions existing. This harvester has a relatively high durability, because the forces are not directly applied to the ceramic. The dependences of the generating output characteristics of the eye-shaped piezoelectric harvester on the ceramic size and at the materials of the elastic body were studied. The resonance and the output characteristics of the generator were analyzed by using a finite-elementmethod program. Generators were fabricated on the basis of the analytical results and were attached to a frequency-controllable vibrator to measure the output characteristics. Also, the experimental results were compared with the simulated results. The output voltages of the generator were increase when ceramic is width was decreased. When the ceramic's length was decreased found to, the resonance frequency of the generator was decreased. For different materials of the elastic body, the highest voltage was obtained at the lowest resonance frequency when brass was used.

  13. Domain-orientation-controlled potassium niobate family piezoelectric materials with hydrothermal powders.

    PubMed

    Fujiuchi, Yukiko; Morita, Takeshi

    2014-10-01

    Materials of the potassium niobate family, as lead-free piezoelectric materials, are expected to be alternative materials to Pb(Zr,Ti)O3 (PZT) because of their good piezoelectric properties, high Curie temperature, and so on. In particular, single-crystal potassium niobate is a promising ferroelectric material as a surface acoustic substrate and for functional optical effects. It is, however, well known that single crystals are difficult to fabricate because of the instability caused by temperature, external stress, and other factors. PMID:25265169

  14. 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.

  15. Microstructure Characterization Of Lead-Free Solders Depending On Alloy Composition

    NASA Astrophysics Data System (ADS)

    Panchenko, Iuliana; Mueller, Maik; Wolter, Klaus-Juergen

    2010-11-01

    Fatigue and crack nucleation in solder joints is basically associated with changes in the microstructure. Therefore the microstructure evolution of SnAgCu solder joints during solidification and subsequent application is an important subject for reliability investigations and physics of failure analysis. The scope of this study is a systematic overview of the as-cast microstructures in small sized lead-free SnAgCu solder spheres after solidification. A total of 32 alloy compositions have been investigated with varying Ag content from 0 to 5 wt.% and varying Cu content from 0 to 1.2 wt.%. The solder spheres had a diameter of approx. 270 ?m and were all manufactured under the similar conditions. Subsequent cross-sectioning was carried out in order to analyze the microstructure by optical and electron microscopy as well as Electron Backscatter Diffraction and Energy Dispersive X-ray Spectroscopy. The results allow a comprehensive overview of the dependence of the as-cast microstructure on the solder composition. It is shown that strong changes in microstructure can be caused by small changes in solder composition. In addition, a solidification phenomenon known as cyclic twinning has been found in the samples. Three different microstructures related to that phenomenon will be presented and detailed characterizations of these structures are given in this study. These microstructures differ in their appearance by solidification morphology, phase distribution as well as grain structure and can be described as follows: 1. large dentritic areas of different grain orientations which are characterized by approx. 60 twin boundaries; 2. areas of small ?-Sn cells with approx. 60 twin relation and larger intermetallic precipitates; 3. large grains consisting of a ?-Sn matrix with very fine intermetallic precipitates and high angle grain boundaries between adjacent grains.

  16. 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.}

  17. Effect of sintering temperature on composition, microstructure and electrical properties of K0.5Na0.5NbO3 ceramics

    NASA Astrophysics Data System (ADS)

    Singh, Rajan; Kulkarni, A. R.; Harendranath, C. S.

    2014-02-01

    Lead free potassium sodium niobate (K0.5Na0.5NbO3) ceramic powders were synthesized by colloidal coating method. The calcined powders (800 C) were sintered conventionally at three different temperatures (1050 C, 1100 C and 1150 C) and the effect of sintering temperature on density, microstructure, composition and electrical properties was investigated. All the samples showed a single phase perovskite structure with orthorhombic symmetry similar to KNbO3 ceramics. Microstructure examined under FEG-SEM revealed an optimum microstructure, in terms of grain size, porosity and uniformity, at the sintering temperature of 1100 C, which also showed density of 92% of ?Th. As the sintering temperature increased the X-ray diffraction peaks shifted to lower 2? values indicating excess volatilization of Na at higher temperature as compared to K. This was further confirmed through elemental Probe X-ray microanalysis and ICP-AES studies. Dielectric constant (?r), dielectric loss (tan?), ferroelectric (P-E loop) and piezoelectric (d33) properties showed considerable improvement and leakage current decreased with increasing sintering temperature. The sample sintered at 1100 C showed marked improvement in maximum dielectric constant (573) at RT at 1 kHz, minimum tangent loss (0.04) at RT at 1 kHz, maximum remnant polarization (13.5 ?C/cm2), lower leakage current (7.610-7 A/cm2) and maximum d33 value (100 pC/N).

  18. 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.

  19. Ceramic-polymer nanocomposites with increased dielectric permittivity and low dielectric loss

    SciTech Connect

    Bhardwaj, Sumit Paul, Joginder; Raina, K. K.; Thakur, N. S.; Kumar, Ravi

    2014-04-24

    The use of lead free materials in device fabrication is very essential from environmental point of view. We have synthesized the lead free ferroelectric polymer nanocomposite films with increased dielectric properties. Lead free bismuth titanate has been used as active ceramic nanofillers having crystallite size 24nm and PVDF as the polymer matrix. Ferroelectric ?-phase of the polymer composite films was confirmed by X-ray diffraction pattern. Mapping data confirms the homogeneous dispersion of ceramic particles into the polymer matrix. Frequency dependent dielectric constant increases up to 43.4 at 100Hz, whereas dielectric loss decreases with 7 wt% bismuth titanate loading. This high dielectric constant lead free ferroelectric polymer films can be used for energy density applications.

  20. Dynamic response of a piezoelectric flapping wing

    NASA Astrophysics Data System (ADS)

    Kumar, Alok; Khandwekar, Gaurang; Venkatesh, S.; Mahapatra, D. R.; Dutta, S.

    2015-03-01

    Piezo-composite membranes have advantages over motorized flapping where frequencies are high and certain coupling between bending and twisting is useful to generate lift and forward flight. We draw examples of fruit fly and bumble bee. Wings with Piezo ceramic PZT coating are realized. The passive mechanical response of the wing is characterized experimentally and validated using finite element simulation. Piezoelectric actuation with uniform electrode coating is characterized and optimal frequencies for flapping are identified. The experimental data are used in an empirical model and advanced ratio for a flapping insect like condition for various angular orientations is estimated.

  1. Laser tuners using circular piezoelectric benders

    NASA Technical Reports Server (NTRS)

    Mcelroy, J. H.; Thompson, P. E.; Walker, H. E.; Johnson, E. H.; Radecki, D. J.; Reynolds, R. S.

    1975-01-01

    The paper presents the results of an experimental evaluation of a new type of piezoelectric ceramic device designed for use as a laser mirror tuner. Thin plates made from various materials were assembled into a circular bimorph configuration and tested for linearity of movement, maximum travel, and resonant frequency for varying conditions of clamping torque and mirror loading values. Most of the devices tested could accept mirror diameters up to approximately 1.3 cm and maintain a resonant frequency above 2 kHz. Typical mirror translation without measurable tilt was plus or minus 20 micrometers or greater for applied voltages of less than plus or minus 300 V.

  2. Optimization of Piezoelectric Electrical Generators Powered by Random Vibrations

    E-print Network

    Lefeuvre, E; Richard, C; Petit, L; Guyomar, D

    2007-01-01

    This paper compares the performances of a vibrationpowered electrical generators using PZT piezoelectric ceramic associated to two different power conditioning circuits. A new approach of the piezoelectric power conversion based on a nonlinear voltage processing is presented and implemented with a particular power conditioning circuit topology. Theoretical predictions and experimental results show that the nonlinear processing technique may increase the power harvested by a factor up to 4 compared to the Standard optimization technique. Properties of this new technique are analyzed in particular in the case of broadband, random vibrations, and compared to those of the Standard interface.

  3. Structural ceramics

    SciTech Connect

    Wachtman, J.B. Jr.

    1989-01-01

    The present work discusses opportunities for application of structural ceramics in heat engines, industrial-wear parts, prosthetics and bearings; conceptual and detailed design principles for structural ceramics; the processing, consolidation, and properties of members of the SiC family of structural ceramics; and the silicon nitride and sialon families of hot-pressed, sintered, and reaction-bonded, structural ceramics. Also discussed are partially-stabilized zirconia and zirconia-toughened ceramics for structural applications, the processing methods and mechanisms of fiber-reinforcement in ceramic-matrix fiber-reinforced composites, and the tribological properties of structural ceramics.

  4. Multiscale Modeling of Mechanical Shock Behavior of Environmentally-Benign Lead-Free Solders in Electronic Packaging

    NASA Astrophysics Data System (ADS)

    Fei, Huiyang

    With the increasing focus on developing environmentally benign electronic packages, lead-free solder alloys have received a great deal of attention. Mishandling of packages, during manufacture, assembly, or by the user may cause failure of solder joint. A fundamental understanding of the behavior of lead-free solders under mechanical shock conditions is lacking. Reliable experimental and numerical analyses of lead-free solder joints in the intermediate strain rate regime need to be investigated. This dissertation mainly focuses on exploring the mechanical shock behavior of lead-free tin-rich solder alloys via multiscale modeling and numerical simulations. First, the macroscopic stress/strain behaviors of three bulk lead-free tin-rich solders were tested over a range of strain rates from 0.001/s to 30/s. Finite element analysis was conducted to determine appropriate specimen geometry that could reach a homogeneous stress/strain field and a relatively high strain rate. A novel self-consistent true stress correction method is developed to compensate the inaccuracy caused by the triaxial stress state at the post-necking stage. Then the material property of micron-scale intermetallic was examined by microcompression test. The accuracy of this measure is systematically validated by finite element analysis, and empirical adjustments are provided. Moreover, the interfacial property of the solder/intermetallic interface is investigated, and a continuum traction-separation law of this interface is developed from an atomistic-based cohesive element method. The macroscopic stress/strain relation and microstructural properties are combined together to form a multiscale material behavior via a stochastic approach for both solder and intermetallic. As a result, solder is modeled by porous plasticity with random voids, and intermetallic is characterized as brittle material with random vulnerable region. Thereafter, the porous plasticity fracture of the solders and the brittle fracture of the intermetallics are coupled together in one finite element model. Finally, this study yields a multiscale model to understand and predict the mechanical shock behavior of lead-free tin-rich solder joints. Different fracture patterns are observed for various strain rates and/or intermetallic thicknesses. The predictions have a good agreement with the theory and experiments.

  5. Experimental Study of Relationships between Ultrasonic Attenuation and Dispersion for Ceramic Matrix Composite

    NASA Astrophysics Data System (ADS)

    Naumenko, A. A.; Shcherbinin, S. A.; Makariev, D. I.; Rybyanets, A. N.

    In this paper an experimental study of different ceramic matrix composites with high elastic losses and dispersion (porous piezoceramics, composites ceramics/crystals) were carried out. Complex sets of elastic, dielectric, and piezoelectric parameters of the porous piezoceramics and ceramic matrix piezocomposites were determined by the impedance spectroscopy method using Piezoelectric Resonance Analysis software. Microstructure of polished and chipped surfaces of composite samples was observed with the optical and scanning electron microcopies. Experimental frequency dependencies of attenuation coefficients and ultrasonic velocities for different ceramic matrix composites were compared with the theoretical results obtained using general Kramers-Kronig relations between the ultrasonic attenuation and dispersion.

  6. 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.

  7. Effect of Pb(Fe{sub 1/2}Nb{sub 1/2})O{sub 3} modification on dielectric and piezoelectric properties of Pb(Mg{sub 1/3}Nb{sub 2/3})O{sub 3}-PbZr{sub 0.52}Ti{sub 0.48}O{sub 3} ceramics

    SciTech Connect

    Luo, Nengneng; Li, Qiang; Xia, Zhiguo

    2011-09-15

    Highlights: {yields} 10 mol% PFN modified PMN-PZT relaxor ferroelectric ceramics were prepared by the conventional solid-state mixed-oxide technique, and their structure, dielectric and piezoelectric properties were studied. {yields} At the frequency of 1 kHz, the maximum dielectric constant at room temperature ({epsilon}{sub r}) was 3519 and maximum dielectric constant ({epsilon}{sub m}) was 20,475, corresponding to the (0.9 - x)PMN-0.1PFN-xPZT ceramic composition of x = 0.8. While the sample with composition of x = 0.3 possessed the maximum dielectric relaxor factor of {gamma} = 1.94. The Curie temperature T{sub c} could be higher than 300 {sup o}C around morphotropic phase boundary (MPB) area which is much higher than some other system. {yields} The largest d{sub 33} could be as high as 318 pC/N when x = 0.9. And the maximum remnant polarization P{sub r} was 28.3 {mu}C/cm{sup 2} at x = 0.4. -- Abstract: 10 mol% Pb(Fe{sub 1/2}Nb{sub 1/2})O{sub 3} (PFN) modified Pb(Mg{sub 1/3}Nb{sub 2/3})O{sub 3}-PbZr{sub 0.52}Ti{sub 0.48}O{sub 3} (PMN-PZT) relaxor ferroelectric ceramics with compositions of (0.9 - x)PMN-0.1PFN-xPZT (x = 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8 and 0.9) were prepared. X-ray diffraction investigations indicated that as-prepared ceramics were of pure perovskite phase and the sample with composition of x = 0.8 was close to morphotropic phase boundary (MPB) between rhombohedral and tetragonal phase. Dielectric properties of the as-prepared ceramics were measured, and the Curie temperature (T{sub c}) increased sharply with increasing PZT content and could be higher than 300 {sup o}C around morphotropic phase boundary (MPB) area. At 1 kHz, the sample with composition of x = 0.1 had the largest room temperature dielectric constant {epsilon}{sub r} = 3519 and maximum dielectric constant {epsilon}{sub m} = 20,475 at T{sub m}, while the sample with composition of x = 0.3 possessed the maximum dielectric relaxor factor of {gamma} = 1.94. The largest d{sub 33} = 318 pC/N could be obtained from as-prepared ceramics at x = 0.9. The maximum remnant polarization (P{sub r} = 28.3 {mu}C/cm{sup 2}) was obtained from as-prepared ceramics at x = 0.4.

  8. Piezoelectric cantilever sensors

    NASA Technical Reports Server (NTRS)

    Shih, Wan Y. (Inventor); Shih, Wei-Heng (Inventor); Shen, Zuyan (Inventor)

    2008-01-01

    A piezoelectric cantilever with a non-piezoelectric, or piezoelectric tip useful as mass and viscosity sensors. The change in the cantilever mass can be accurately quantified by monitoring a resonance frequency shift of the cantilever. For bio-detection, antibodies or other specific receptors of target antigens may be immobilized on the cantilever surface, preferably on the non-piezoelectric tip. For chemical detection, high surface-area selective absorbent materials are coated on the cantilever tip. Binding of the target antigens or analytes to the cantilever surface increases the cantilever mass. Detection of target antigens or analytes is achieved by monitoring the cantilever's resonance frequency and determining the resonance frequency shift that is due to the mass of the adsorbed target antigens on the cantilever surface. The use of a piezoelectric unimorph cantilever allows both electrical actuation and electrical sensing. Incorporating a non-piezoelectric tip (14) enhances the sensitivity of the sensor. In addition, the piezoelectric cantilever can withstand damping in highly viscous liquids and can be used as a viscosity sensor in wide viscosity range.

  9. Microstructural Evolution of Lead-Free Solder Joints in Ultrasonic-Assisted Soldering

    NASA Astrophysics Data System (ADS)

    Ji, Hongjun; Wang, Qiang; Li, Mingyu

    2015-10-01

    Solder joint reliability greatly depends on the microstructure of the solder matrix and the morphology of intermetallic compounds (IMCs) in the joints. Addition of strengthening phases such as carbon nanotubes and ceramic particles to solder joints to improve their properties has been widely studied. In this work, ultrasonic vibration (USV) of casting ingots was applied to considerably improve their microstructure and properties, and the resulting influence on fluxless soldering of Cu/Sn-3.0Ag-0.5Cu/Cu joints and their microstructural evolution was investigated. It was demonstrated that USV application during reflow of Sn-based solder had favorable effects on ?-Sn grain size refinement as well as the growth and distribution of various IMC phases within the joints. The ?-Sn grain size was significantly refined as the ultrasound power was increased, with a reduction of almost 90% from more than 100 ?m to below 10 ?m. Long and large Cu6Sn5 tubes in the solder matrix of the joints were broken into tiny ones. Needle-shaped Ag3Sn was transformed into flake-shaped. These IMCs were mainly precipitated along ?-Sn phase boundaries. High-temperature storage tests indicated that the growth rate of interfacial IMCs in joints formed with USV was slower than in conventional reflow joints. The mechanisms of grain refinement and IMC fragmentation are discussed and related to the ultrasonic effects.

  10. Adaptive piezoelectric sensoriactuator

    NASA Technical Reports Server (NTRS)

    Clark, Jr., Robert L. (Inventor); Vipperman, Jeffrey S. (Inventor); Cole, Daniel G. (Inventor)

    1996-01-01

    An adaptive algorithm implemented in digital or analog form is used in conjunction with a voltage controlled amplifier to compensate for the feedthrough capacitance of piezoelectric sensoriactuator. The mechanical response of the piezoelectric sensoriactuator is resolved from the electrical response by adaptively altering the gain imposed on the electrical circuit used for compensation. For wideband, stochastic input disturbances, the feedthrough capacitance of the sensoriactuator can be identified on-line, providing a means of implementing direct-rate-feedback control in analog hardware. The device is capable of on-line system health monitoring since a quasi-stable dynamic capacitance is indicative of sustained health of the piezoelectric element.

  11. Effect of lead-free solder joint's size and configuration on mechanical properties, microstructure, and aging kinetics

    NASA Astrophysics Data System (ADS)

    Tashtoush, Tariq H.

    The properties of Lead-Free solder joints continue to change over a very long time while in service. The assessment of long-term service life of electronics packages invariably misses the effect of solder joint size and configuration, and may thus end up to be seriously misleading. One of the goals of the present research is to develop a fundamental understanding of the effects of solder joint size on the mechanical properties of microstructure and aging kinetics. This understanding will help in the assessment of the reliability of Lead-Free solder joints. For this purpose, two different room temperature properties, namely, shear strength and micro-hardness, are studied and the microstructure is also evaluated to find the correlation between them. These properties are measured before and after aging for different lengths of time at different temperatures. Five common Lead-Free alloys are selected for the present study, which are SAC105, SAC205, SAC305, SnCu and SnAg. The study also addresses effects of solder joint size by focusing on 20 mil (508?m) and 30 mil (760?m) diameter solder spheres reflowed onto solder mask defined OSP coated Cu pads with a typical manufacturing Lead-Free reflow profile. Isothermal aging is conducted for up to 500 hours at temperatures of 70, 100, and 125C. As expected, the resulting room temperature properties decrease with aging time, and at a faster rate for higher aging temperatures. The acceleration factors that are extracted for the evolution of each property are different for the selected alloy and joint sizes.

  12. Shear Strength of Eutectic Sn-Bi Lead-Free Solders After Corrosion Testing and Thermal Aging

    NASA Astrophysics Data System (ADS)

    Mostofizadeh, Milad; Pippola, Juha; Frisk, Laura

    2014-05-01

    Low-cost manufacturing in the electronics industry is becoming more demanding, particularly in the production of consumer electronics. Such manufacturing processes require reliable and low-cost lead-free solders. Among the low temperature lead-free solders, eutectic Sn-Bi solder has attracted a great deal of interest since it offers good reliability comparable to that of Sn-Pb solders. In this paper, the shear strength of eutectic 42Sn-58Bi (wt.%) lead-free solder was studied using combinations of environmental tests including thermal aging at 100 C, salt spray test, and a sequential combination of these tests. Microstructural studies on samples were performed at different time intervals of testing. To study the effect of salt spray and thermal aging on the mechanical reliability, shear testing was performed on the samples. Failure analysis including fractography on samples was conducted at different time intervals using a scanning electron microscope. Considerable corrosion was observed after the salt spray test. This was found to have a significant effect on the shear strength of the solder joints. Additionally, thermal aging was found to cause coarsening and to increase the thickness of intermetallic layers. This was also found to adversely affect the shear strength. The combination test was found to have the most significant effect, as the lowest shear strengths were seen after this testing.

  13. Model of piezoelectric self powered supply for wearable devices

    NASA Astrophysics Data System (ADS)

    Meddad, M.; Eddiai, A.; Chrif, A.; Hajjaji, A.; Boughaleb, Y.

    2014-07-01

    With the development in a few latter years, of micros electromechanical technology (MEMS), the demand in wearable electronics and in cordless detectors is more and more important. These wearable devices have needed more of autonomy and independence in energy. Materials piezoelectric (often called intelligent materials) can be employed like mechanisms to convert the mechanical energy, due to vibration usually ambient, in energy electric. This one can be stored and used in place of conventional battery which presents certain disadvantages such as lasted limited life as well as congestion. In this article, one presents a power analytical model generated by a smart structure of type PZT that can be used as supply energy for electronic device. This model allows the determination of suitable sizes and vibration levels of piezoelectric material for to generate an optimal energy supply for a mobile phone. Two types of vibration mode have been compared as a function of characteristics and piezoelectric ceramic sizes.

  14. JOINT RIGIDITY ASSESSMENT WITH PIEZOELECTRIC WAFERS AND ACOUSTIC WAVES

    SciTech Connect

    Montoya, Angela C.; Maji, Arup K.

    2010-02-22

    There has been an interest in the development of rapid deployment satellites. In a modular satellite design, different panels of specific functions can be pre-manufactured. The satellite can then be assembled and tested just prior to deployment. Traditional vibration testing is time-consuming and expensive. An alternative test method to evaluate the connection between two plates will be proposed. The method investigated and described employs piezoelectric wafers to induce and sense lamb waves in two aluminum plates, which were joined by steel brackets to form an 'L-Style' joint. Lamb wave behavior and piezoelectric material properties will be discussed; the experimental setup and results will be presented. A set of 4 piezoelectric ceramic wafers were used alternately as source and sensor. The energy transmitted was shown to correlate with a mechanical assessment of the joint, demonstrating that this method of testing is a feasible and reliable way to inspect the rigidity of joints.

  15. Electrical Properties and Power Considerations of a Piezoelectric Actuator

    NASA Technical Reports Server (NTRS)

    Jordan, T.; Ounaies, Z.; Tripp, J.; Tcheng, P.

    1999-01-01

    This paper assesses the electrical characteristics of piezoelectric wafers for use in aeronautical applications such as active noise control in aircraft. Determination of capacitive behavior and power consumption is necessary to optimize the system configuration and to design efficient driving electronics. Empirical relations are developed from experimental data to predict the capacitance and loss tangent of a PZT5A ceramic as nonlinear functions of both applied peak voltage and driving frequency. Power consumed by the PZT is the rate of energy required to excite the piezoelectric system along with power dissipated due to dielectric loss and mechanical and structural damping. Overall power consumption is thus quantified as a function of peak applied voltage and driving frequency. It was demonstrated that by incorporating the variation of capacitance and power loss with voltage and frequency, satisfactory estimates of power requirements can be obtained. These relations allow general guidelines in selection and application of piezoelectric actuators and driving electronics for active control applications.

  16. Optimum shape control of flexible beams by piezo-electric actuators

    NASA Technical Reports Server (NTRS)

    Baz, A.; Poh, S.

    1987-01-01

    The utilization of piezoelectric actuators in controlling the static deformation and shape of flexible beams is examined. An optimum design procedure is presented to enable the selection of the optimal location, thickness and excitation voltage of the piezoelectric actuators in a way that would minimize the deflection of the beam to which these actuators are bonded. Numerical examples are presented to illustrate the application of the developed optimization procedure in minimizing structural deformation of beams using ceramic and polymeric piezoelectric actuators bonded to the beams with a typical bonding agent. The obtained results emphasize the importance of the devised rational produce in designing beam-actuator systems with minimal elastic distortions.

  17. Piezoelectric energy harvesting solutions.

    PubMed

    Cali, Renato; Rongala, Udaya Bhaskar; Camboni, Domenico; Milazzo, Mario; Stefanini, Cesare; de Petris, Gianluca; Oddo, Calogero Maria

    2014-01-01

    This paper reviews the state of the art in piezoelectric energy harvesting. It presents the basics of piezoelectricity and discusses materials choice. The work places emphasis on material operating modes and device configurations, from resonant to non-resonant devices and also to rotational solutions. The reviewed literature is compared based on power density and bandwidth. Lastly, the question of power conversion is addressed by reviewing various circuit solutions. PMID:24618725

  18. Piezoelectrically Enhanced Photocathodes

    NASA Technical Reports Server (NTRS)

    Beach, Robert A.; Nikzad, Shouleh; Bell, Lloyd Douglas; Strittmatter, Robert

    2011-01-01

    Doping of photocathodes with materials that have large piezoelectric coefficients has been proposed as an alternative means of increasing the desired photoemission of electrons. Treating cathode materials to increase emission of electrons is called "activation" in the art. It has been common practice to activate photocathodes by depositing thin layers of suitable metals (usually, cesium). Because cesium is unstable in air, fabrication of cesiated photocathodes and devices that contain them must be performed in sealed tubes under vacuum. It is difficult and costly to perform fabrication processes in enclosed, evacuated spaces. The proposed piezoelectrically enhanced photocathodes would have electron-emission properties similar to those of cesiated photocathodes but would be stable in air, and therefore could be fabricated more easily and at lower cost. Candidate photocathodes include nitrides of elements in column III of the periodic table . especially compounds of the general formula Al(x)Ga(1.x)N (where 0< or = x < or =.1). These compounds have high piezoelectric coefficients and are suitable for obtaining response to ultraviolet light. Fabrication of a photocathode according to the proposal would include inducement of strain in cathode layers during growth of the layers on a substrate. The strain would be induced by exploiting structural mismatches among the various constituent materials of the cathode. Because of the piezoelectric effect in this material, the strain would give rise to strong electric fields that, in turn, would give rise to a high concentration of charge near the surface. Examples of devices in which piezoelectrically enhanced photocathodes could be used include microchannel plates, electron- bombarded charge-coupled devices, image tubes, and night-vision goggles. Piezoelectrically enhanced photocathode materials could also be used in making highly efficient monolithic photodetectors. Highly efficient and stable piezoelectrically enhanced, ultraviolet-sensitive photocathodes and photodetectors could be fabricated by use of novel techniques for growing piezoelectrically enhanced layers, in conjunction with thinning and dopant-selective etching techniques.

  19. Laminated piezoelectric transformer

    NASA Technical Reports Server (NTRS)

    Vazquez Carazo, Alfredo (Inventor)

    2006-01-01

    A laminated piezoelectric transformer is provided using the longitudinal vibration modes for step-up voltage conversion applications. The input portions are polarized to deform in a longitudinal plane and are bonded to an output portion. The deformation of the input portions is mechanically coupled to the output portion, which deforms in the same longitudinal direction relative to the input portion. The output portion is polarized in the thickness direction relative its electrodes, and piezoelectrically generates a stepped-up output voltage.

  20. Piezoelectric Energy Harvesting Solutions

    PubMed Central

    Cali, Renato; Rongala, Udaya Bhaskar; Camboni, Domenico; Milazzo, Mario; Stefanini, Cesare; de Petris, Gianluca; Oddo, Calogero Maria

    2014-01-01

    This paper reviews the state of the art in piezoelectric energy harvesting. It presents the basics of piezoelectricity and discusses materials choice. The work places emphasis on material operating modes and device configurations, from resonant to non-resonant devices and also to rotational solutions. The reviewed literature is compared based on power density and bandwidth. Lastly, the question of power conversion is addressed by reviewing various circuit solutions. PMID:24618725

  1. University of California, Irvine Environmental Health and Safety www.ehs.uci.edu Questions Call: (949) 824-6200 Version 1.0 Lead Free UCI

    E-print Network

    Mease, Kenneth D.

    : (949) 824-6200 Version 1.0 Lead Free UCI Autoclave Tape - Get the Lead Out Environmental Health risks of lead pollution, and Replace lead containing autoclave tape with lead-free autoclave tape for FREE. Autoclave tape used in some laboratories may contain levels of lead that exceed the hazardous

  2. Advances in Fine Pitch Lead Free Assembly Process Ravi Doraiswami, Sandeep Sankararaman,Woopoung Kim, Jmg Li, Zhuqing Zhang, Piyush Gupta, Kensuke Nakanishi',

    E-print Network

    Swaminathan, Madhavan

    Advances in Fine Pitch Lead Free Assembly Process Ravi Doraiswami, Sandeep Sankararaman for selecting high electrical performance 100 micron pitch lead free solder bumping process. This is achieved subjected to thermal cychg (air to ai). This evaluation leads to the selection of the hest pad contigumtion

  3. Aluminum Nitride Thin Films on Titanium for Piezoelectric MEMS Applications Seth Boeshore, Emily Parker, Vanni Lughi, Noel C. MacDonald

    E-print Network

    MacDonald, Noel C.

    Aluminum Nitride Thin Films on Titanium for Piezoelectric MEMS Applications Seth Boeshore, Emily Parker, Vanni Lughi, Noel C. MacDonald University of California, Santa Barbara Highlytextured aluminum, biocompatibility, and high fracture toughness. As a piezoelectric ceramic, aluminum nitride is compatible

  4. Structural Ceramics Database

    National Institute of Standards and Technology Data Gateway

    SRD 30 NIST Structural Ceramics Database (Web, free access) The NIST Structural Ceramics Database (WebSCD) provides evaluated materials property data for a wide range of advanced ceramics known variously as structural ceramics, engineering ceramics, and fine ceramics.

  5. On Ceramics.

    ERIC Educational Resources Information Center

    School Arts, 1982

    1982-01-01

    Presents four ceramics activities for secondary-level art classes. Included are directions for primitive kiln construction and glaze making. Two ceramics design activities are described in which students make bizarrely-shaped lidded jars, feet, and footwear. (AM)

  6. Optimization of the piezoelectric response of 0-3 composites: a modeling approach

    NASA Astrophysics Data System (ADS)

    Chambion, B.; Goujon, L.; Badie, L.; Mugnier, Y.; Barthod, C.; Galez, C.; Wiebel, S.; Venet, C.

    2011-11-01

    Finite element modeling is used in this study to optimize the electromechanical behavior of 0-3 composites according to the material properties of their constituents. Our modeling approach considers an 'extended' 2D representative volume element (RVE) with randomly dispersed piezoelectric particles. A variable distribution of their polarization axes is also implemented because a full periodic arrangement of fillers and a unique poling orientation are unrealistic in practice. Comparisons with a simpler RVE and with an analytical model based on the Mori-Tanaka approach are performed as a function of the particle concentration for the elastic, dielectric and piezoelectric homogenized properties. An optimization of the piezoelectric response of 0-3 composites according to material considerations is then computed, allowing it to be shown that the piezoelectric strain coefficient is not the only relevant parameter and that lead-free piezoelectric fillers such as LiNbO3 and ZnO are competitive alternatives. Finally, the piezoelectric responses of 0-3 composites with different filler arrangements are quantitatively compared to 1-3 composites and to the corresponding bulk material.

  7. Evaluation of electromechanical coupling parameters of piezoelectric materials by using piezoelectric cantilever with coplanar electrode structure in quasi-stasis.

    PubMed

    Zheng, Xuejun; Zhu, Yuankun; Liu, Xun; Liu, Jing; Zhang, Yong; Chen, Jianguo

    2014-02-01

    Based on Timoshenko beam theory, a principle model is proposed to establish the relationship between electric charge and excitation acceleration, and in quasi-stasis we apply the direct piezoelectric effect of multilayer cantilever with coplanar electrode structure to evaluate the piezoelectric strain coefficient d15 and electromechanical coupling coefficient k15. They are measured as 678 pC/N and 0.74 for the commercial piezoelectric ceramic lead zirconate titanate (PZT-51) bulk specimen and 656 pC/N and 0.63 for the lead magnesium niobate (PMN) bulk specimen, and they are in agreement with the calibration and simulation values. The maximum of relative errors is less than 4.2%, so the proposed method is reliable and convenient. PMID:24474142

  8. Tailoring the structure and piezoelectric properties of BiFeO3-(K0.5Bi0.5)TiO3-PbTiO3 ceramics for high temperature applications

    NASA Astrophysics Data System (ADS)

    Bennett, J.; Bell, A. J.; Stevenson, T. J.; Comyn, T. P.

    2013-10-01

    There is a growing requirement for piezoelectric materials and systems which can operate in extreme environments, for example, oil & gas, and aerospace. Here, we present the high temperature BiFeO3-K0.5Bi0.5TiO3-PbTiO3 (BF-KBT-PT) polycrystalline perovskite system. X-ray diffraction, impedance analysis, and Berlincourt measurements reveal a large region of phase coexistence, which can be tailored to optimise performance; Tc and the tetragonal spontaneous strain correlate strongly with the PbTiO3 concentration. The highest temperature composition has a d33 of 140 pmV-1 with a Tc = 542 C, occupying previously unchartered territory on the classical d33-TC plot.

  9. Structural Ceramics

    NASA Technical Reports Server (NTRS)

    1986-01-01

    This publication is a compilation of abstracts and slides of papers presented at the NASA Lewis Structural Ceramics Workshop. Collectively, these papers depict the scope of NASA Lewis' structural ceramics program. The technical areas include monolithic SiC and Si3N4 development, ceramic matrix composites, tribology, design methodology, nondestructive evaluation (NDE), fracture mechanics, and corrosion.

  10. Poly(gamma-benzyl alpha, L glutamic acid)-based piezoelectric films & microfibers

    NASA Astrophysics Data System (ADS)

    Farrar, Dawnielle

    Piezoelectric materials in use today are often made of ceramic crystals. Although most ceramics offer high piezoelectricity, they are brittle and require expensive processing conditions. For applications where flexibility is required in addition to high piezoelectric activity, polymers are a very attractive alternative. An ideal piezoelectric material is the one where the piezoelectricity and mechanical properties can be altered individually so that the mechanical stiffness of the material can be varied for particular applications or tuned to match that of the surroundings (e.g. air or water) for increased transduction sensitivity. This is typically achieved by production of composite materials containing piezoelectric and matrix components. Here, we present new composite films and microfibers based on the biopolymer, poly(gamma-benzyl alpha,L-glutamate) (PBLG) and discuss their fabrication and piezoelectric properties. Fabrication of PBLG films and fibers was made possible by PBLG's extreme solubility in organic solvents. By simultaneous poling and curing of PBLG/methylmethacrylate (MMA) mixture solutions via corona charging, we fabricated a flexible composite film [80% PBLG and 20% Poly(methylmethacrylate) (PMMA)] with approximately 20% of the PBLG molecules oriented normal to the film surface. This PBLG film exhibited high piezoelectricity (d33 = 20 pC/N), and its Young's modulus was 1 GPa. However, significant amount of MMA evaporated during the corona charging process that precluded the fabrication of films with pre-determined PBLG-PMMA composition. We also fabricated thick composite disk (thickness: 3 cm) by breakdown charging and thermal polymerization of PBLG/PMMA mixture solution, a process that does not allow MMA evaporation. The composite disk exhibited low piezoelectricity (d33 3 pC/N) due to low PBLG content (< 30%); however, its mechanical characteristics were similar to those of PMMA, indicating that the piezoelectricity and mechanical strength are independently related to the two polymer components of the composite disk. By electrospinning PBLG/dichloromethane (DCM) solutions under potentials of -(1215) kV, we produced piezoelectric microfibers (diameter: 100 nm) with nearly all of the PBLG dipoles oriented along the fiber axis, evidenced by x-ray diffraction. The PBLG fibers showed high piezoelectricity (d 33 = 32 pC/N), and an elastic modulus of 570 MPa. Both the piezoelectric film and fiber systems can be fabricated directly from solution in a mould or on a substrate. Due to the versatility in the fabrication process and the high piezoelectricity, these materials show great promise as transducer materials for loud speakers, microphones, and/or energy harvesting devices.

  11. Diaphragm Pump With Resonant Piezoelectric Drive

    NASA Technical Reports Server (NTRS)

    Izenson, Michael G.; Kline-Schoder, Robert J.; Shimko, Martin A.

    2007-01-01

    A diaphragm pump driven by a piezoelectric actuator is undergoing development. This pump is intended to be a prototype of lightweight, highly reliable pumps for circulating cooling liquids in protective garments and high-power electronic circuits, and perhaps for some medical applications. The pump would be highly reliable because it would contain no sliding seals or bearings that could wear, the only parts subject to wear would be two check valves, and the diaphragm and other flexing parts could be designed, by use of proven methods, for extremely long life. Because the pump would be capable of a large volumetric flow rate and would have only a small dead volume, its operation would not be disrupted by ingestion of gas, and it could be started reliably under all conditions. The prior art includes a number piezoelectrically actuated diaphragm pumps. Because of the smallness of the motions of piezoelectric actuators (typical maximum strains only about 0.001), the volumetric flow rates of those pumps are much too small for typical cooling applications. In the pump now undergoing development, mechanical resonance would be utilized to amplify the motion generated by the piezoelectric actuator and thereby multiply the volumetric flow rate. The prime mover in this pump would be a stack of piezoelectric ceramic actuators, one end of which would be connected to a spring that would be part of a spring-and-mass resonator structure. The mass part of the resonator structure would include the pump diaphragm (see Figure 1). Contraction of the spring would draw the diaphragm to the left, causing the volume of the fluid chamber to increase and thereby causing fluid to flow into the chamber. Subsequent expansion of the spring would push the diaphragm to the right, causing the volume of the fluid chamber to decrease, and thereby expelling fluid from the chamber. The fluid would enter and leave the chamber through check valves. The piezoelectric stack would be driven electrically to make it oscillate at the resonance frequency of the spring and- mass structure. This frequency could be made high enough (of the order of 400 Hz) that the masses of all components could be made conveniently small. The resonance would amplify the relatively small motion of the piezoelectric stack (a stroke of the order of 10 m) to a diaphragm stroke of the order of 0.5 mm. The exact amplification factor would depend on the rate of damping of oscillations; this, in turn, would depend on details of design and operation, including (but not limited to) the desired pressure rise and volumetric flow rate. In order to obtain resonance with large displacement, the damping rate must be low enough that the energy imparted to the pumped fluid on each stroke is much less than the kinetic and potential energy exchanged between the mass and spring during each cycle of oscillation. To minimize the power demand of the pump, a highly efficient drive circuit would be used to excite the piezoelectric stack. This circuit (see Figure 2) would amount to a special-purpose regenerative, switching power supply that would operate in a power-source mode during the part of an oscillation cycle when the excitation waveform was positive and in a power-recovery mode during the part of the cycle when the excitation waveform was negative. The circuit would include a voltage-boosting dc-to-dc converter that would convert between a supply potential of 24 Vdc and the high voltage needed to drive the piezoelectric stack. Because of the power-recovery feature, the circuit would consume little power. It should be possible to build the circuit as a compact unit, using readily available components.

  12. Lead zirconate titanate ceramics

    SciTech Connect

    Walker, B.E. Jr.

    1986-12-02

    This patent describes a lead zirconate titanate (PZT) piezoelectric ceramic composition which, based on total composition weight, consists essentially of a solid solution of lead zirconate and lead titanate in a PbZrO/sub 3/:PbTiO/sub 3/ ratio from about 0.505:0.495 to about 0.54:0.46; a halide salt selected from the group consisting of fluorides and chlorides of alkali metal and alkaline earth elements and mixtures thereof except for francium and radium in an amount from about 0.5 to 2 weight percent; and an oxide selected from the group consisting of magnesium, barium, scandium, aluminum, lanthanum, praesodynium, neodymium, samarium, and mixtures thereof in an amount from about 0.5 to about 6 weight percent, the relative amount of oxide being from about 1 to about 4 times that of the halide.

  13. Dielectric spectroscopy of Dy{sub 2}O{sub 3} doped (K{sub 0.5}Na{sub 0.5})NbO{sub 3} piezoelectric ceramics

    SciTech Connect

    Mahesh, P. Subhash, T. Pamu, D.

    2014-04-24

    We report the dielectric properties of (K{sub 0.5}Na{sub 0.5})NbO{sub 3} ceramics doped with x wt% of Dy{sub 2}O{sub 3} (x= 0.0-1.5 wt%) using the broadband dielectric spectroscopy. The X-ray diffraction studies showed the formation of perovskite structure signifying that Dy{sub 2}O{sub 3} diffuse into the KNN lattice. Samples doped with x > 0.5 wt% exhibit smaller grain size and lower relative densities. The dielectric properties of KNN ceramics doped with Dy{sub 2}O{sub 3} are enhanced by increasing the Dy{sup 3+} content; among the compositions studied, x = 0.5 wt% exhibited the highest dielectric constant and lowest loss at 1MHz over the temperature range of 30C to 400C. All the samples exhibit maximum dielectric constant at the Curie temperature (? 326C) and a small peak in the dielectric constant at around 165C is due to a structural phase transition.

  14. Field-induced phase transition and relaxor character in submicrometer-structured lead-free (Bi0.5Na0.5)0.94Ba0.06TiO3 piezoceramics at the morphotropic phase boundary.

    PubMed

    Pardo, Lorena; Mercadelli, Elisa; Garca, Alvaro; Brebl, Klaus; Galassi, Carmen

    2011-09-01

    Submicrometer-structured (Bi(0.5)Na(0.5))(0.94)Ba(0.06)TiO(3) ceramics ((G) < 720 nm) from nanopowders were studied. The real part of the optimum room temperature set of piezoelectric coefficients obtained from resonances of the BNBT6 dense ceramic disks and shear plates [d(31) = (-37 + 1.33i) pCN(-1), d(15) = (158.3 - 8.31i) pCN(-1), k(t) = 40.4%, k(p) = 26.8%, and k(15) = 40.2%] and d(33) (148 pCN(-1)) can be compared with the reported properties for coarse-grained ceramics. Shear resonance of thickness-poled plates is observed at T = 140C. Permittivity versus temperature curves of poled samples show relaxor character up to T(i) = 230C on heating and T(i) = 210C on cooling of the depoled samples. The phase transition from the room-temperature ferroelectric (FE) to a low-temperature non-polar at zero field (LTNPZF) phase can be observed as a sharp jump in ?(?)(33)'(T) curves or, as the degree of poling decreases, as a soft change of slope of the curves at T(FE-LTNPZF) = T(d) = 100C. This dielectric anomaly is not observed on cooling of depoled samples, because the FE phase is field-induced. The observed macroscopic piezoelectric activity above T(d) is a consequence of the coexistence of nanoregions of the FE phase in the interval between T(FE-LTNPZF) and T(i). PMID:21937323

  15. Piezoelectric wave motor

    DOEpatents

    Yerganian, Simon Scott (Lee's Summit, MO)

    2001-07-17

    A piezoelectric motor having a stator in which piezoelectric elements are contained in slots formed in the stator transverse to the desired wave motion. When an electric field is imposed on the elements, deformation of the elements imposes a force perpendicular to the sides of the slot, deforming the stator. Appropriate frequency and phase shifting of the electric field will produce a wave in the stator and motion in a rotor. In a preferred aspect, the piezoelectric elements are configured so that deformation of the elements in direction of an imposed electric field, generally referred to as the d.sub.33 direction, is utilized to produce wave motion in the stator. In a further aspect, the elements are compressed into the slots so as to minimize tensile stresses on the elements in use.

  16. Piezoelectric and pyroelectric polymers

    SciTech Connect

    Davis, G.T.

    1995-12-01

    Many polar polymers can be made to exhibit piezoelectric and pyroelectric properties by permanently aligning their dipoles in an electric field. The largest response is found in semi-crystalline polymers which exhibit a polar crystal phase which is amenable to reorientation in an applied electric field. The properties of poly(vinylidenefluoride), copolymers of vinyl idenefluoride and trifluoroethylene, nylon 7 and nylon 11 are compared. Polarization distribution across the thickness of such polymer films are discussed and novel techniques for the construction of piezoelectric bimorphs from the above copolymers are presented.

  17. Full Piezoelectric Multilayer-Stacked Hybrid Actuation/Transduction Systems

    NASA Technical Reports Server (NTRS)

    Su, Ji; Jiang, Xiaoning; Zu, Tian-Bing

    2011-01-01

    The Stacked HYBATS (Hybrid Actuation/Transduction system) demonstrates significantly enhanced electromechanical performance by using the cooperative contributions of the electromechanical responses of multilayer, stacked negative strain components and positive strain components. Both experimental and theoretical studies indicate that, for Stacked HYBATS, the displacement is over three times that of a same-sized conventional flextensional actuator/transducer. The coupled resonance mode between positive strain and negative strain components of Stacked HYBATS is much stronger than the resonance of a single element actuation only when the effective lengths of the two kinds of elements match each other. Compared with the previously invented hybrid actuation system (HYBAS), the multilayer Stacked HYBATS can be designed to provide high mechanical load capability, low voltage driving, and a highly effective piezoelectric constant. The negative strain component will contract, and the positive strain component will expand in the length directions when an electric field is applied on the device. The interaction between the two elements makes an enhanced motion along the Z direction for Stacked-HYBATS. In order to dominate the dynamic length of Stacked-HYBATS by the negative strain component, the area of the cross-section for the negative strain component will be much larger than the total cross-section areas of the two positive strain components. The transverse strain is negative and longitudinal strain positive in inorganic materials, such as ceramics/single crystals. Different piezoelectric multilayer stack configurations can make a piezoelectric ceramic/single-crystal multilayer stack exhibit negative strain or positive strain at a certain direction without increasing the applied voltage. The difference of this innovation from the HYBAS is that all the elements can be made from one-of-a-kind materials. Stacked HYBATS can provide an extremely effective piezoelectric constant at both resonance and off resonance frequencies. The effective piezoelectric constant can be alternated by varying the size of each component, the degree of the pre-curvature of the positive strain components, the thickness of each layer in the multilayer stacks, and the piezoelectric constant of the material used. Because all of the elements are piezoelectric components, Stacked HYBATS can serve as projector and receiver for underwater detection. The performance of this innovation can be enhanced by improving the piezoelectric properties.

  18. Improvement of low-frequency characteristics of piezoelectric speakers based on acoustic diaphragms.

    PubMed

    Kim, Hye Jin; Yang, Woo Seok; No, Kwangsoo

    2012-09-01

    The vibrational characteristics of 3 types of the acoustic diaphragms are investigated to enhance the output acoustic performance of the piezoelectric ceramic speaker in a low-frequency range. In other to achieve both a higher output sound pressure level and wider frequency range of the piezoelectric speaker, we have proposed a rubber/resin bi-layer acoustic diaphragm. The theoretical square-root dependence of the fundamental resonant frequency on the thickness and Young's modulus of the acoustic diaphragm was verified by finite-element analysis simulation and laser scanning vibrometer measurement. The simulated resonant frequencies for each diaphragm correspond well to the measured results. From the simulated and measured resonant frequency results, it is found that the fundamental resonant frequency of the piezoelectric ceramic speaker can be designed by adjusting the thickness ratio of the rubber/resin bi-layer acoustic diaphragm. Compared with a commercial piezoelectric speaker, the fabricated piezoelectric ceramic speaker with the rubber/resin bi-layer diaphragm has at least 10 dB higher sound pressures in the low-frequency range of less than 1 kHz. PMID:23007777

  19. Direct strain energy harvesting in automobile tires using piezoelectric PZT-polymer composites

    NASA Astrophysics Data System (ADS)

    van den Ende, D. A.; van de Wiel, H. J.; Groen, W. A.; van der Zwaag, S.

    2012-01-01

    Direct piezoelectric strain energy harvesting can be used to power wireless autonomous sensors in environments where low frequency, high strains are present, such as in automobile tires during operation. However, these high strains place stringent demands on the materials with respect to mechanical failure or depolarization, especially at elevated temperatures. In this work, three kinds of ceramic-polymer composite piezoelectric materials were evaluated and compared against state-of-the-art piezoelectric materials. The new composites are unstructured and structured composites containing granular lead zirconate titanate (PZT) particles or PZT fibers in a polyurethane matrix. The composites were used to build energy harvesting patches which were attached to a tire and tested under simulated rolling conditions. The energy density of the piezoelectric ceramic-polymer composite materials is initially not as high as that of the reference materials (a macro-fiber composite and a polyvinylidene fluoride polymer). However, the area normalized power output of the composites after temperature and strain cycling is comparable to that of the reference devices because the piezoelectric ceramic-polymer composites did not degrade during operation.

  20. Tuning and parameter optimization of a digital integral controller for uniform droplet spray applications using lead-free tin-copper solder

    E-print Network

    De Castro, Eloisa M

    2009-01-01

    The advent of legislation restricting the use of lead in electronics requires innovation and refinement in processes for creating lead-free solder spheres for wafer bumping and other surface mount technology. Operation ...

  1. Ceramic Processing

    SciTech Connect

    EWSUK,KEVIN G.

    1999-11-24

    Ceramics represent a unique class of materials that are distinguished from common metals and plastics by their: (1) high hardness, stiffness, and good wear properties (i.e., abrasion resistance); (2) ability to withstand high temperatures (i.e., refractoriness); (3) chemical durability; and (4) electrical properties that allow them to be electrical insulators, semiconductors, or ionic conductors. Ceramics can be broken down into two general categories, traditional and advanced ceramics. Traditional ceramics include common household products such as clay pots, tiles, pipe, and bricks, porcelain china, sinks, and electrical insulators, and thermally insulating refractory bricks for ovens and fireplaces. Advanced ceramics, also referred to as ''high-tech'' ceramics, include products such as spark plug bodies, piston rings, catalyst supports, and water pump seals for automobiles, thermally insulating tiles for the space shuttle, sodium vapor lamp tubes in streetlights, and the capacitors, resistors, transducers, and varistors in the solid-state electronics we use daily. The major differences between traditional and advanced ceramics are in the processing tolerances and cost. Traditional ceramics are manufactured with inexpensive raw materials, are relatively tolerant of minor process deviations, and are relatively inexpensive. Advanced ceramics are typically made with more refined raw materials and processing to optimize a given property or combination of properties (e.g., mechanical, electrical, dielectric, optical, thermal, physical, and/or magnetic) for a given application. Advanced ceramics generally have improved performance and reliability over traditional ceramics, but are typically more expensive. Additionally, advanced ceramics are typically more sensitive to the chemical and physical defects present in the starting raw materials, or those that are introduced during manufacturing.

  2. Ceramic burner

    SciTech Connect

    Laux, W.; Hebel, R.; Artelt, P.; Esfeld, G.; Jacob, A.

    1981-03-31

    Improvements in the mixing body and supporting structure of a molded-ceramic-brick burner enable the burner to withstand the vibrations induced during its operation. Designed for the combustion chambers of air heaters, the burner has a mixing body composed of layers of shaped ceramic bricks that interlock and are held together vertically by a ceramic holding bar. The mixing body is shaped like a mushroom - the upper layers have a larger radius than the lower ones.

  3. Effects of metallic nanoparticle doped flux on the interfacial intermetallic compounds between lead-free solder ball and copper substrate

    SciTech Connect

    Sujan, G.K. Haseeb, A.S.M.A. Afifi, A.B.M.

    2014-11-15

    Lead free solders currently in use are prone to develop thick interfacial intermetallic compound layers with rough morphology which are detrimental to the long term solder joint reliability. A novel method has been developed to control the morphology and growth of intermetallic compound layers between lead-free Sn3.0Ag0.5Cu solder ball and copper substrate by doping a water soluble flux with metallic nanoparticles. Four types of metallic nanoparticles (nickel, cobalt, molybdenum and titanium) were used to investigate their effects on the wetting behavior and interfacial microstructural evaluations after reflow. Nanoparticles were dispersed manually with a water soluble flux and the resulting nanoparticle doped flux was placed on copper substrate. Lead-free Sn3.0Ag0.5Cu solder balls of diameter 0.45 mm were placed on top of the flux and were reflowed at a peak temperature of 240 C for 45 s. Angle of contact, wetting area and interfacial microstructure were studied by optical microscopy, field emission scanning electron microscopy and energy-dispersive X-ray spectroscopy. It was observed that the angle of contact increased and wetting area decreased with the addition of cobalt, molybdenum and titanium nanoparticles to flux. On the other hand, wettability improved with the addition of nickel nanoparticles. Cross-sectional micrographs revealed that both nickel and cobalt nanoparticle doping transformed the morphology of Cu{sub 6}Sn{sub 5} from a typical scallop type to a planer one and reduced the intermetallic compound thickness under optimum condition. These effects were suggested to be related to in-situ interfacial alloying at the interface during reflow. The minimum amount of nanoparticles required to produce the planer morphology was found to be 0.1 wt.% for both nickel and cobalt. Molybdenum and titanium nanoparticles neither appear to undergo alloying during reflow nor have any influence at the solder/substrate interfacial reaction. Thus, doping of flux with appropriate metallic nanoparticles can be successfully used to control the morphology and growth of intermetallic compound layers at the solder/substrate interface which is expected to lead to better reliability of electronic devices. - Highlights: A novel nanodoped flux method has been developed to control the growth of IMCs. Ni doped flux improves the wettability, but Co, Mo and Ti deteriorate it. Ni and Co doped flux gives planer IMC morphology through in-situ alloying effect. 0.1 wt.% Ni and Co addition into flux gives the lowest interfacial IMC thickness. Mo and Ti doped flux does not have any influence at the interfacial reaction.

  4. Reduced risk of acute poisoning in Australian cattle from used motor oils after introduction of lead-free petrol.

    PubMed

    Burren, B G; Reichmann, K G; McKenzie, R A

    2010-06-01

    Lead (Pb) poisoning of cattle has been relatively common in Australia and sump oil has been identified as an important cause of Pb toxicity for cattle because they seem to have a tendency to drink it. Lead-free petrol has been available in Australia since 1975, so the aim of this study was to assess the current risk to cattle from drinking used automotive oils. Sump or gear box oil was collected from 56 vehicles being serviced. The low levels of Pb found suggest that the removal of leaded petrol from the Australian market as a public health measure has benefited cattle by eliminating the risk of acute poisoning from used engine oil. PMID:20553575

  5. Evaluation of Electrochemical Migration on Printed Circuit Boards with Lead-Free and Tin-Lead Solder

    NASA Astrophysics Data System (ADS)

    He, Xiaofei; Azarian, Michael H.; Pecht, Michael G.

    2011-09-01

    To evaluate the current leakage and electrochemical migration behavior on printed circuit boards with eutectic tin-lead and lead-free solder, IPC B-24 comb structures were exposed to 65C and 88% relative humidity conditions under direct-current (DC) bias for over 1500 h. These boards were processed with either Sn-3.0Ag-0.5Cu solder or Sn-37Pb solder. In addition to solder alloy, board finish (organic solderability preservative versus lead-free hot air solder leveling), spacing (25 mil versus 12.5 mil), and voltage (40 V versus 5 V bias) were also assessed by using in situ measurements of surface insulation resistance (SIR) and energy-dispersive spectroscopy after testing. It was shown that an initial increase of SIR was caused by consumption of electroactive species on the surface, intermittent drops of SIR were caused by dendritic growth, and a long-term SIR decline was caused by electrodeposition of a metallic layer. The prolonged SIR decline of Sn-3.0Ag-0.5Cu boards was simulated by three-dimensional (3D) progressive and instantaneous nucleation models, whose predictions were compared with experimental data. Sn-37Pb boards exhibited comigration of Sn, Pb, and Cu, while Sn-3.0Ag-0.5Cu boards incurred comigration of Sn, Ag, and Cu. Among the migrated species, Sn always dominated and was observed as either a layer or in polyhedral deposits, Pb was the most common element found in the dendrites, Cu was a minor constituent, and Ag migrated only occasionally. Compared with solder alloy, board finishes played a secondary role in affecting SIR due to their complexation with or dissolution into the solder. The competing effect between electric field and spacing was also investigated.

  6. Emission factors for gases and particle-bound substances produced by firing lead-free small-caliber ammunition.

    PubMed

    Wingfors, H; Svensson, K; Hgglund, L; Hedenstierna, S; Magnusson, R

    2014-01-01

    Lead-free ammunition is becoming increasingly popular because of the environmental and human health issues associated with the use of leaded ammunition. However, there is a lack of data on the emissions produced by firing such ammunition. We report emission factors for toxic gases and particle-bound compounds produced by firing lead-free ammunition in a test chamber. Carbon monoxide, ammonia, and hydrogen cyanide levels within the chamber were analysed by Fourier transform infrared spectroscopy, while total suspended particles and respirable particles were determined gravimetrically. The metal content of the particulate emissions was determined and the associated organic compounds were characterized in detail using a method based on thermal desorption coupled to gas chromatography and mass spectrometry. The particulate matter (?30 mg/round) consisted primarily of metals such as Cu, Zn, and Fe along with soot arising from incomplete combustion. Nitrogen-containing heterocyclic aromatic compounds such as carbazole, quinolone, and phenazine were responsible for some of the 25 most significant chromatographic peaks, together with PAHs, diphenylamine, and phthalates. Emission factors were determined for PAHs and oxygenated PAHs; the latter were less abundant in the gun smoke particles than in domestic dust and diesel combustion smoke. This may be due to the oxygen-deficient conditions that occur when the gun is fired. By using an electrical low pressure impactor, it was demonstrated that more than 90% of the particles produced immediately after firing the weapon had diameters of less than 30 nm, and so most of the gun smoke particles belonged to the nanoparticle regime. PMID:24188168

  7. Lead-free epitaxial ferroelectric material integration on semiconducting (100) Nb-doped SrTiO3 for low-power non-volatile memory and efficient ultraviolet ray detection

    NASA Astrophysics Data System (ADS)

    Kundu, Souvik; Clavel, Michael; Biswas, Pranab; Chen, Bo; Song, Hyun-Cheol; Kumar, Prashant; Halder, Nripendra N.; Hudait, Mantu K.; Banerji, Pallab; Sanghadasa, Mohan; Priya, Shashank

    2015-07-01

    We report lead-free ferroelectric based resistive switching non-volatile memory (NVM) devices with epitaxial (1-x)BaTiO3-xBiFeO3 (x?=?0.725) (BT-BFO) film integrated on semiconducting (100) Nb (0.7%) doped SrTiO3 (Nb:STO) substrates. The piezoelectric force microscopy (PFM) measurement at room temperature demonstrated ferroelectricity in the BT-BFO thin film. PFM results also reveal the repeatable polarization inversion by poling, manifesting its potential for read-write operation in NVM devices. The electroforming-free and ferroelectric polarization coupled electrical behaviour demonstrated excellent resistive switching with high retention time, cyclic endurance, and low set/reset voltages. X-ray photoelectron spectroscopy was utilized to determine the band alignment at the BT-BFO and Nb:STO heterojunction, and it exhibited staggered band alignment. This heterojunction is found to behave as an efficient ultraviolet photo-detector with low rise and fall time. The architecture also demonstrates half-wave rectification under low and high input signal frequencies, where the output distortion is minimal. The results provide avenue for an electrical switch that can regulate the pixels in low or high frequency images. Combined this work paves the pathway towards designing future generation low-power ferroelectric based microelectronic devices by merging both electrical and photovoltaic properties of BT-BFO materials.

  8. Phase transitions, relaxor behavior, and large strain response in LiNbO3-modified Bi0.5(Na0.80K0.20)0.5TiO3 lead-free piezoceramics

    NASA Astrophysics Data System (ADS)

    Hao, Jigong; Bai, Wangfeng; Li, Wei; Shen, Bo; Zhai, Jiwei

    2013-07-01

    The effect of LiNbO3 (LN) addition on the ferroelectric behavior and piezoelectric properties of Bi0.5(Na0.80K0.20)0.5TiO3 (BNKT20) lead-free piezoceramics were systematically investigated. Results showed that the LN substitution into BNKT20 induced a transition from coexistence of ferroelectric tetragonal and rhombohedral phases to relaxor pseudocubic phases, which is accompanied by the significant disruption of ferroelectric order and with the shift of the ferroelectric-relaxor transition temperature TF-R down to room temperature. Accordingly, a large accompanying normalized strain of 0.38% (corresponding to a large signal d33* of 475 pm/V) were obtained in BNKT20 with 2.5 mol. %LN addition near the phase boundary. Temperature-dependent measurements of both polarization and strain from room temperature to 120 C suggested that the origin of the large strain is due to a reversible field-induced ergodic relaxor-to-ferroelectric phase transformation. Moreover, an attractive property for application as high-temperature dielectrics was obtained in this system modified with 8 mol. %LN with a high permittivity of 1760 15% from room temperature up to 500 C, spanning a range of about 450 C.

  9. Lead-free epitaxial ferroelectric material integration on semiconducting (100) Nb-doped SrTiO3 for low-power non-volatile memory and efficient ultraviolet ray detection.

    PubMed

    Kundu, Souvik; Clavel, Michael; Biswas, Pranab; Chen, Bo; Song, Hyun-Cheol; Kumar, Prashant; Halder, Nripendra N; Hudait, Mantu K; Banerji, Pallab; Sanghadasa, Mohan; Priya, Shashank

    2015-01-01

    We report lead-free ferroelectric based resistive switching non-volatile memory (NVM) devices with epitaxial (1-x)BaTiO3-xBiFeO3 (x?=?0.725) (BT-BFO) film integrated on semiconducting (100) Nb (0.7%) doped SrTiO3 (Nb:STO) substrates. The piezoelectric force microscopy (PFM) measurement at room temperature demonstrated ferroelectricity in the BT-BFO thin film. PFM results also reveal the repeatable polarization inversion by poling, manifesting its potential for read-write operation in NVM devices. The electroforming-free and ferroelectric polarization coupled electrical behaviour demonstrated excellent resistive switching with high retention time, cyclic endurance, and low set/reset voltages. X-ray photoelectron spectroscopy was utilized to determine the band alignment at the BT-BFO and Nb:STO heterojunction, and it exhibited staggered band alignment. This heterojunction is found to behave as an efficient ultraviolet photo-detector with low rise and fall time. The architecture also demonstrates half-wave rectification under low and high input signal frequencies, where the output distortion is minimal. The results provide avenue for an electrical switch that can regulate the pixels in low or high frequency images. Combined this work paves the pathway towards designing future generation low-power ferroelectric based microelectronic devices by merging both electrical and photovoltaic properties of BT-BFO materials. PMID:26202946

  10. Optimum vibration control of flexible beams by piezo-electric actuators

    NASA Technical Reports Server (NTRS)

    Baz, A.; Poh, S.

    1987-01-01

    The utilization of piezoelectric actuators in controlling the structural vibrations of flexible beams is examined. A Modified Independent Modal Space Control (MIMSC) method is devised to enable the selection of the optimal location, control gains and excitation voltage of the piezoelectric actuators in a way that would minimize the amplitudes of vibrations of beams to which these actuators are bonded, as well as the input control energy necessary to suppress these vibrations. The developed method accounts for the effects that the piezoelectric actuators have on changing the elastic and inertial properties of the flexible beams. Numerical examples are presented to illustrate the application of the developed MIMSC method in minimizing the structural vibrations of beams of different materials when subjected to different loading and end conditions using ceramic or polymeric piezoelectric actuators. The obtained results emphasize the importance of the devised method in designing more realistic active control systems for flexible beams, in particular, and large flexible structures in general.

  11. Optimum vibration control of flexible beams by piezo-electric actuators

    NASA Technical Reports Server (NTRS)

    Baz, A.; Poh, S.; Studer, P.

    1988-01-01

    The utilization of piezoelectric actuators in controlling the structural vibrations of flexible beams is examined. A Modified Independent Modal Space Control (MIMSC) method is devised to enable the selection of the optimal location, control gains and excitation voltage of the piezoelectric actuators in a way that would minimize the amplitudes of vibrations of beams to which these actuators are bonded, as well as the input control energy necessary to suppress these vibrations. The developed method accounts for the effects that the piezoelectric actuators have on changing the elastic and inertial properties of the flexible beams. Numerical examples are presented to illustrate the application of the developed MIMSC method in minimizing the structural vibrations of beams of different materials when subjected to different loading and end conditions using ceramic or polymeric piezoelectric actuators. The obtained results emphasize the importance of the devised method in designing more realistic active control systems for flexible beams, in particular, and large flexible structures in general.

  12. Torsional wave propagation in a circular plate of piezoelectric radial phononic crystals

    NASA Astrophysics Data System (ADS)

    Shu, Haisheng; Zhao, Lei; Shi, Xiaona; Liu, Wei; Shi, Dongyan; Kong, Fankai

    2015-11-01

    Piezoelectric rings are periodically introduced and inserted in a base plate along the radial direction, forming a one-dimensional circular plate of piezoelectric radial phononic crystals (CPPRPC). The transfer matrix of the torsional wave between adjacent units is derived in cylindrical coordinates. Then, by introducing Lyapunov exponents, the phenomenon of the torsional wave band gap is analyzed with consideration of outer control. Furthermore, the effects of some factors, namely, radial span ratio, inner radius of the plate, open-circuit, and short-circuit statuses of the piezoelectric ceramics, on the torsional wave band gap are also discussed in detail. The results show that the distinct band gaps are obtained for torsional waves propagating in CPPRPC. Together with the outer control gain, structural and piezoelectric parameters have significant effects on the band gaps. In particular, middle-low frequency band gaps can be effectively obtained by rationally varying the outer active control gain.

  13. Generating the characteristics of a modified unimorph-type piezoelectric harvester

    NASA Astrophysics Data System (ADS)

    Jeong, Seong-Su; Park, Tae-Gone

    2014-07-01

    Recently, research on energy harvesting system with piezoelectric ceramics has been conducted. To compensate for the problem of low generating power compared to other energy harvesters, many researchers have studied piezoelectric harvesters in order to obtain high output. In this paper, four kinds of unimorph based piezoelectric harvesters are proposed, and their generating characteristics are studied. The piezoelectric harvesters have three, four, six, and eight unimorph arms, respectively, and the arms are symmetrically arranged from one central point. The centrosymmetric structure of the harvesters guarantees more stable and multiplied generation compared to a cantilever-type harvester because the arms of the former harvester resonate at the same frequency. The resonance frequency, the output voltage, the displacement, and the stress characteristics of the generator were analyzed by using a finite element method (FEM) program. Harvesters were fabricated on the basis of the analysis results. Experimental results were compared with simulated results. Also, the efficiency of each model was verified.

  14. Use of piezoelectric actuators in active vibration control of rotating machinery

    NASA Technical Reports Server (NTRS)

    Lin, Reng Rong; Palazzolo, Alan B.; Kascak, Albert F.; Montague, Gerald

    1990-01-01

    Theoretical and test results for the development of piezoelectric-actuator-based active vibration control (AVC) are presented. The evolution of this technology starts with an ideal model of the actuator and progresses to a more sophisticated model where the pushers force the squirrel cage ball bearing supports of a rotating shaft. The piezoelectric pushers consist of a stack of piezoelectric ceramic disks that are arranged on top of one another and connected in parallel electrically. This model consists of a prescribed displacement that is proportional to the input voltage and a spring that represents the stiffness of the stack of piezoelectric disks. System tests were carried out to stabilize the AVC system, verify its effectiveness in controlling vibration, and confirm the theory presented.

  15. Piezoelectric Actuator/Sensor Technology at Rockwell

    NASA Technical Reports Server (NTRS)

    Neurgaonkar, Ratnakar R.

    1996-01-01

    We describe the state-of-the art of piezoelectric materials based on perovskite and tungsten bronze families for sensor, actuator and smart structure applications. The microstructural defects in these materials have been eliminated to a large extent and the resulting materials exhibit exceedingly high performance for various applications. The performance of Rockwell actuators/sensors is at least 3 times better than commercially available products. These high performance actuators are being incorporated into various applications including, DOD, NASA and commercial. The multilayer actuator stacks fabricated from our piezoceramics are advantageous for sensing and high capacitance applications. In this presentation, we will describe the use of our high performance piezo-ceramics for actuators and sensors, including multilayer stacks and composite structures.

  16. [Ceramic posts].

    PubMed

    Mainjot, Amlie; Legros, Caroline; Vanheusden, Alain

    2006-01-01

    As a result of ceramics and all-ceram technologies development esthetic inlay core and abutments flooded the market. Their tooth-colored appearance enhances restoration biomimetism principally on the marginal gingiva area. This article reviews indications and types of cores designed for natural teeth and implants. PMID:17432533

  17. Lead-free solder

    DOEpatents

    Anderson, Iver E. (Ames, IA); Terpstra, Robert L. (Ames, IA)

    2001-05-15

    A Sn--Ag--Cu eutectic alloy is modified with one or more low level and low cost alloy additions to enhance high temperature microstructural stability and thermal-mechanical fatigue strength without decreasing solderability. Purposeful fourth or fifth element additions in the collective amount not exceeding about 1 weight % (wt. %) are added to Sn--Ag--Cu eutectic solder alloy based on the ternary eutectic Sn--4.7%Ag--1.7%Cu (wt. %) and are selected from the group consisting essentially of Ni, Fe, and like-acting elements as modifiers of the intermetallic interface between the solder and substrate to improve high temperature solder joint microstructural stability and solder joint thermal-mechanical fatigue strength.

  18. Ceramic Methyltrioxorhenium

    E-print Network

    Herrmann, R; Eickerling, G; Helbig, C; Hauf, C; Miller, R; Mayr, F; Krug von Nidda, H A; Scheidt, E W; Scherer, W; Herrmann, Rudolf; Troester, Klaus; Eickerling, Georg; Helbig, Christian; Hauf, Christoph; Miller, Robert; Mayr, Franz; Nidda, Hans-Albrecht Krug von; Scheidt, Ernst-Wilhelm; Scherer, Wolfgang

    2006-01-01

    The metal oxide polymeric methyltrioxorhenium [(CH3)xReO3] is an unique epresentative of a layered inherent conducting organometallic polymer which adopts the structural motifs of classical perovskites in two dimensions (2D) in form of methyl-deficient, corner-sharing ReO5(CH3) octahedra. In order to improve the characteristics of polymeric methyltrioxorhenium with respect to its physical properties and potential usage as an inherentconducting polymer we tried to optimise the synthetic routes of polymeric modifications of 1 to obtain a sintered ceramic material, denoted ceramic MTO. Ceramic MTO formed in a solvent-free synthesis via auto-polymerisation and subsequent sintering processing displays clearly different mechanical and physical properties from polymeric MTO synthesised in aqueous solution. Ceramic MTO is shown to display activated Re-C and Re=O bonds relative to MTO. These electronic and structural characteristics of ceramic MTO are also reflected by a different chemical reactivity compared with its...

  19. Data-glove-based fuzzy control of piezoelectric forceps actuator

    NASA Astrophysics Data System (ADS)

    Susanto, Ken; Yang, Bingen

    2004-07-01

    This paper discusses a novel concept idea of utilizing smart structure in biomedical, minimum invasive surgery (MIS), MEMS manufacturing assembly line and also as a miniature robotic gripper system. The proposed prototype of a miniature piezoelectric forceps actuator (PFA) is composed of two symmetric slightly curved composite beams which each bonded with piezoelectric ceramic layer. The PFA is an innovative forceps actuator that comes with a data glove. The data glove is simply a custom-made glove with two embedded resistance-bending sensors located on thumb and index fingers. Any users can control opening and closing of the PFA by just wearing the data glove. A thin curved beam theory bonded with piezoelectric ceramic will be derived based on Hamilton's principle and its deflection behavior will be simulated based on distributed transfer function method (DTFM). A feasibility study of simulation open loop data glove-based fuzzy logic controller allows the user to open and close the PFA remotely. The bending movement of the thumb and index finger will be formulated in a table of rules based to produce the necessary output controller gain to control the PFA.

  20. A very promising piezoelectric property of Ta{sub 2}O{sub 5} thin films. II: Birefringence and piezoelectricity

    SciTech Connect

    Audier, M.; Chenevier, B.; Roussel, H.; Vincent, L.; Pena, A.

    2011-08-15

    Birefringent and piezoelectric properties of Ta{sub 2}O{sub 5} ceramic thin films of monoclinic and trigonal structures were analyzed. The birefringence, observed by reflected polarized light microscopy, yields information on thin film microstructures, crystal shapes and sizes and on crystallographic orientations of grains of trigonal structure. Such an information was considered for investigating piezoelectric properties by laser Doppler vibrometry and by piezoresponse force microscopy. The vibration velocity was measured by applying an oscillating electric field between electrodes on both sides of a Ta{sub 2}O{sub 5} film deposited on a Si substrate which was pasted on an isolating mica sheet. In this case, it is shown that the vibration velocity results were not only from a converse piezoelectric effect, proportional to the voltage, but also from the Coulomb force, proportional to the square of the voltage. A huge piezoelectric strain effect, up to 7.6%, is found in the case of Ta{sub 2}O{sub 5} of trigonal structure. From an estimation of the electrical field through the Ta{sub 2}O{sub 5} thin film, this strain likely corresponds to a very high longitudinal coefficient d{sub 33} of several thousand picometers. Results obtained by piezoresponse force microscopy show that trigonal grains exhibit a polarization at zero field, which is probably due to stress caused expansion in the transition monoclinic-trigonal, presented in a previous article (part I). - Graphical abstract: Image of cross-polarized optical microscopy showing grains of trigonal structure embedded in the monoclinic phase (on the left); (a) mounting of the sample for Laser Doppler Vibrometry, sample constituted of several layers and its equivalent electrical circuit; (b) longitudinal displacements due to converse piezoelectric and Coulomb effects and corresponding piezoelectric strain-U{sub app.}. hystereses. Highlights: > A new Ta{sub 2}O{sub 5} trigonal phase is shown to be birefringent and piezoelectric. > This phase is related to a reversible transition with a monoclinic phase. > The piezoelectricity of this trigonal phase is of several thousands of pm/V. > It is compared to piezoelectricity of the monoclinic phase of several tens of pm/V.

  1. Synthesis and Characterization of Lead Free (Na{sub 0.5}K{sub 0.5}){sub NbO3} Ceramics

    SciTech Connect

    Kumar, P.; Palei, P.

    2008-10-23

    NKN (50/50) material was synthesized in single perovskite phase by solid state reaction technique. Existence of mixed phase by XRD analysis, confirmed the MPB nature of the system. Density and grain size were found to be 4.23gm/cm{sup 3} and {approx}5.5({mu}m, respectively. Room temperature value of dielectric constant ({epsilon}{sub r}) and dielectric loss (tan{delta}) at 1 kHz were found to be 425 and 0.004, respectively and the transition temperature (T{sub c}) was found to be {approx}390 deg. C. Development of P-E hystersis loop indicated the ferroelectric nature of the material.

  2. Piezoelectric Resonator with Two Layers

    NASA Technical Reports Server (NTRS)

    Stephanou, Philip J. (Inventor); Black, Justin P. (Inventor)

    2013-01-01

    A piezoelectric resonator device includes: a top electrode layer with a patterned structure, a top piezoelectric layer adjacent to the top layer, a middle metal layer adjacent to the top piezoelectric layer opposite the top layer, a bottom piezoelectric layer adjacent to the middle layer opposite the top piezoelectric layer, and a bottom electrode layer with a patterned structure and adjacent to the bottom piezoelectric layer opposite the middle layer. The top layer includes a first plurality of electrodes inter-digitated with a second plurality of electrodes. A first one of the electrodes in the top layer and a first one of the electrodes in the bottom layer are coupled to a first contact, and a second one of the electrodes in the top layer and a second one of the electrodes in the bottom layer are coupled to a second contact.

  3. Piezoelectric step-motion actuator

    DOEpatents

    Mentesana; Charles P. (Leawood, KS)

    2006-10-10

    A step-motion actuator using piezoelectric material to launch a flight mass which, in turn, actuates a drive pawl to progressively engage and drive a toothed wheel or rod to accomplish stepped motion. Thus, the piezoelectric material converts electrical energy into kinetic energy of the mass, and the drive pawl and toothed wheel or rod convert the kinetic energy of the mass into the desired rotary or linear stepped motion. A compression frame may be secured about the piezoelectric element and adapted to pre-compress the piezoelectric material so as to reduce tensile loads thereon. A return spring may be used to return the mass to its resting position against the compression frame or piezoelectric material following launch. Alternative embodiment are possible, including an alternative first embodiment wherein two masses are launched in substantially different directions, and an alternative second embodiment wherein the mass is eliminated in favor of the piezoelectric material launching itself.

  4. Structural control by the use of piezoelectric active members

    NASA Technical Reports Server (NTRS)

    Fanson, J. L.; Chen, J.-C.

    1987-01-01

    Large Space Structures (LSS) exhibit characteristics which make the LSS control problem different form other control problems. LSS will most likely exhibit low frequency, densely spaced and lightly damped modes. In theory, the number of these modes is infinite. Because these structures are flexible, Vibration Suppression (VS) is an important aspect of LSS operation. In terms of VS, the control actuators should be as low mass as possible, have infinite bandwidth, and be electrically powered. It is proposed that actuators be built into the structure as dual purpose structural elements. A piezoelectric active member is proposed for the control of LSS. Such a device would consist of a piezoelectric actuator and sensor for measuring strain, and screwjack actuator in series for use in quasi-static shape control. An experiment simulates an active member using piezoelectric ceramic thin sheet material on a thin, uniform cantilever beam. The feasibility of using the piezoelectric materials for VS on LSS was demonstrated. Positive positive feedback as a VS control strategy was implemented. Multi-mode VS was achieved with dramatic reduction in dynamic response.

  5. High Temperature Piezoelectric Drill

    NASA Technical Reports Server (NTRS)

    Bao, Xiaoqi; Bar-Cohen, Yoseph; Sherrit, Stewart; Badescu, Mircea; Shrout, Tom

    2012-01-01

    Venus is one of the planets in the solar systems that are considered for potential future exploration missions. It has extreme environment where the average temperature is 460 deg C and its ambient pressure is about 90 atm. Since the existing actuation technology cannot maintain functionality under the harsh conditions of Venus, it is a challenge to perform sampling and other tasks that require the use of moving parts. Specifically, the currently available electromagnetic actuators are limited in their ability to produce sufficiently high stroke, torque, or force. In contrast, advances in developing electro-mechanical materials (such as piezoelectric and electrostrictive) have enabled potential actuation capabilities that can be used to support such missions. Taking advantage of these materials, we developed a piezoelectric actuated drill that operates at the temperature range up to 500 deg C and the mechanism is based on the Ultrasonic/Sonic Drill/Corer (USDC) configuration. The detailed results of our study are presented in this paper

  6. Integration of bulk piezoelectric materials into microsystems

    NASA Astrophysics Data System (ADS)

    Aktakka, Ethem Erkan

    Bulk piezoelectric ceramics, compared to deposited piezoelectric thin-films, provide greater electromechanical coupling and charge capacity, which are highly desirable in many MEMS applications. In this thesis, a technology platform is developed for wafer-level integration of bulk piezoelectric substrates on silicon, with a final film thickness of 5-100microm. The characterized processes include reliable low-temperature (200C) AuIn diffusion bonding and parylene bonding of bulk-PZT on silicon, wafer-level lapping of bulk-PZT with high-uniformity (+/-0.5microm), and low-damage micro-machining of PZT films via dicing-saw patterning, laser ablation, and wet-etching. Preservation of ferroelectric and piezoelectric properties is confirmed with hysteresis and piezo-response measurements. The introduced technology offers higher material quality and unique advantages in fabrication flexibility over existing piezoelectric film deposition methods. In order to confirm the preserved bulk properties in the final film, diaphragm and cantilever beam actuators operating in the transverse-mode are designed, fabricated and tested. The diaphragm structure and electrode shapes/sizes are optimized for maximum deflection through finite-element simulations. During tests of fabricated devices, greater than 12microm PP displacement is obtained by actuation of a 1mm2 diaphragm at 111kHz with <7mW power consumption. The close match between test data and simulation results suggests that the piezoelectric properties of bulk-PZT5A are mostly preserved without any necessity of repolarization. Three generations of resonant vibration energy harvesters are designed, simulated and fabricated to demonstrate the competitive performance of the new fabrication process over traditional piezoelectric deposition systems. An unpackaged PZT/Si unimorph harvester with 27mm3 active device volume produces up to 205microW at 1.5g/154Hz. The prototypes have achieved the highest figure-of-merits (normalized-power-density x bandwidth) amongst previously reported inertial energy harvesters. The fabricated energy harvester is utilized to create an autonomous energy generation platform in 0.3cm3 by system-level integration of a 50-80% efficient power management IC, which incorporates a supply-independent bias circuitry, an active diode for low-dropout rectification, a bias-flip system for higher efficiency, and a trickle battery charger. The overall system does not require a pre-charged battery, and has power consumption of <1microW in active-mode (measured) and <5pA in sleep-mode (simulated). Under lg vibration at 155Hz, a 70mF ultra-capacitor is charged from OV to 1.85V in 50 minutes.

  7. Hybrid piezoelectric energy harvesting transducer system

    NASA Technical Reports Server (NTRS)

    Xu, Tian-Bing (Inventor); Jiang, Xiaoning (Inventor); Su, Ji (Inventor); Rehrig, Paul W. (Inventor); Hackenberger, Wesley S. (Inventor)

    2008-01-01

    A hybrid piezoelectric energy harvesting transducer system includes: (a) first and second symmetric, pre-curved piezoelectric elements mounted separately on a frame so that their concave major surfaces are positioned opposite to each other; and (b) a linear piezoelectric element mounted separately on the frame and positioned between the pre-curved piezoelectric elements. The pre-curved piezoelectric elements and the linear piezoelectric element are spaced from one another and communicate with energy harvesting circuitry having contact points on the frame. The hybrid piezoelectric energy harvesting transducer system has a higher electromechanical energy conversion efficiency than any known piezoelectric transducer.

  8. Piezoelectric wind turbine

    NASA Astrophysics Data System (ADS)

    Kishore, Ravi Anant; Priya, Shashank

    2013-03-01

    In past few years, there has been significant focus towards developing small scale renewable energy based power sources for powering wireless sensor nodes in remote locations such as highways and bridges to conduct continuous health monitoring. These prior efforts have led to the development of micro-scale solar modules, hydrogen fuel cells and various vibration based energy harvesters. However, the cost effectiveness, reliability, and practicality of these solutions remain a concern. Harvesting the wind energy using micro-to-small scale wind turbines can be an excellent solution in variety of outdoor scenarios provided they can operate at few miles per hour of wind speed. The conventional electromagnetic generator used in the wind mills always has some cogging torque which restricts their operation above certain cut-in wind speed. This study aims to develop a novel piezoelectric wind turbine that utilizes bimorph actuators for electro-mechanical energy conversion. This device utilizes a Savonius rotor that is connected to a disk having magnets at the periphery. The piezoelectric actuators arranged circumferentially around the disk also have magnets at the tip which interacts with the magnetic field of the rotating disk and produces cyclical deflection. The wind tunnel experiments were conducted between 2-12 mph of wind speeds to characterize and optimize the power output of the wind turbine. Further, testing was conducted in the open environment to quantify the response to random wind gusts. An attempt was made towards integration of the piezoelectric wind turbine with the wireless sensor node.

  9. Fatigue failure kinetics and structural changes in lead-free interconnects due to mechanical and thermal cycling

    NASA Astrophysics Data System (ADS)

    Fiedler, Brent Alan

    Environmental and human health concerns drove European parliament to mandate the Reduction of Hazardous Substances (RoHS) for electronics. This was enacted in July 2006 and has practically eliminated lead in solder interconnects. There is concern in the electronics packaging community because modern lead-free solder is rich in tin. Presently, near-eutectic tin-silver-copper solders are favored by industry. These solders are stiffer than the lead-tin near-eutectic alloys, have a higher melting temperature, fewer slip systems, and form intermetallic compounds (IMC) with Cu, Ni and Ag, each of which tend to have a negative effect on lifetime. In order to design more reliable interconnects, the experimental observation of cracking mechanisms is necessary for the correct application of existing theories. The goal of this research is to observe the failure modes resulting from mode II strain and to determine the damage mechanisms which describe fatigue failures in 95.5 Sn- 4.0 Ag - 0.5 Cu wt% (SAC405) lead-free solder interconnects. In this work the initiation sites and crack paths were characterized for SAC405 ball-grid array (BGA) interconnects with electroless-nickel immersion-gold (ENIG) pad-finish. The interconnects were arranged in a perimeter array and tested in fully assembled packages. Evaluation methods included monotonic and displacement controlled mechanical shear fatigue tests, and temperature cycling. The specimens were characterized using metallogaphy, including optical and electron microscopy as well as energy dispersive spectroscopy (EDS) and precise real-time electrical resistance structural health monitoring (SHM). In mechanical shear fatigue tests, strain was applied by the substrates, simulating dissimilar coefficients of thermal expansion (CTE) between the board and chip-carrier. This type of strain caused cracks to initiate in the soft Sn-rich solder and grow near the interface between the solder and intermetallic compounds (IMC). The growth near the interface was found to be caused by dislocation pile-ups at the IMC when the plastic zone ahead of the crack tip reached this interface. In temperature cycling testing, strains arose within the interconnect due to CTE mismatch between the solder and IMC. The substrates had matched CTE for all specimens in this research. Because of this, all the temperature cycling cracks were observed at interfaces, generally between the solder and IMC. Additionally, real-time electrical resistance may be a useful non-destructive evaluation (NDE) tool for the empirical observation of fatigue cracking in ball-grid arrays (BGA) during both mechanical and temperature cycling tests.

  10. Efficient Driving of Piezoelectric Transducers Using a Biaxial Driving Technique

    PubMed Central

    2015-01-01

    Efficient driving of piezoelectric materials is desirable when operating transducers for biomedical applications such as high intensity focused ultrasound (HIFU) or ultrasound imaging. More efficient operation reduces the electric power required to produce the desired bioeffect or contrast. Our preliminary work [Cole et al. Journal of Physics: Condensed Matter. 2014;26(13):135901.] suggested that driving transducers by applying orthogonal electric fields can significantly reduce the coercivity that opposes ferroelectric switching. We present here the experimental validation of this biaxial driving technique using piezoelectric ceramics typically used in HIFU. A set of narrow-band transducers was fabricated with two sets of electrodes placed in an orthogonal configuration (following the propagation and the lateral mode). The geometry of the ceramic was chosen to have a resonance frequency similar for the propagation and the lateral mode. The average ( s.d.) resonance frequency of the samples was 465.1 ( 1.5) kHz. Experiments were conducted in which each pair of electrodes was driven independently and measurements of effective acoustic power were obtained using the radiation force method. The efficiency (acoustic/electric power) of the biaxial driving method was compared to the results obtained when driving the ceramic using electrodes placed only in the pole direction. Our results indicate that the biaxial method increases efficiency from 50% to 125% relative to the using a single electric field. PMID:26418550

  11. The piezoelectric response of nanotwinned BaTiO3.

    PubMed

    Hlinka, J; Ondrejkovic, P; Marton, P

    2009-03-11

    The piezoelectric properties of tetragonal BaTiO(3) crystals with a very high density of 90 degrees twin domain boundaries are analyzed in the framework of the Ginzburg-Landau-Devonshire theory. Computer simulations predict a considerable enhancement of piezoelectric coefficients for domain thicknesses below 50 nm. This enhancement is much larger than the effect of the domain wall broadening mechanism of Rao and Wang (2007 Appl. Phys. Lett. 90 041915), but it is still a too weak effect to explain the domain density enhancement observed in the experiments of Wada and Tsurumi (2004 Br. Ceram. Trans. 103 93). The phenomenon observed here should nevertheless manifest in materials with nanoscopic domains, such as relaxor ferroelectrics and artificial ferroelectric nanostructures. PMID:19417537

  12. Thickness vibrations of a piezoelectric plate with dissipation.

    PubMed

    Lee, Peter C Y; Liu, Ninghui; Ballato, Arthur

    2004-01-01

    The three-dimensional (3-D) equations of linear piezoelectricity with quasi-electrostatic approximation are extended to include losses attributed to the acoustic viscosity and electrical conductivity. These equations are used to investigate effects of dissipation on the propagation of plane waves in an infinite solid and forced thickness vibrations in an infinite piezoelectric plate with general symmetry. For a harmonic plane wave propagating in an arbitrary direction in an unbounded solid, the complex eigenvalue problem is solved from which the effective elastic stiffness, viscosity, and conductivity are computed. For the forced thickness vibrations of an infinite plate, the complex coupling factor K*, input admittance Y are derived and an explicit, approximate expression for K* is obtained in terms of material properties. Effects of the viscosity and conductivity on the resonance frequency, modes, admittance, attenuation coefficient, dynamic time constant, coupling factor, and quality factor are calculated and examined for quartz and ceramic barium titanate plates. PMID:14995016

  13. Microstructure and In Situ Observations of Undercooling for Nucleation of [beta]-Sn Relevant to Lead-Free Solder Alloys

    SciTech Connect

    Elmer, John W.; Specht, Eliot D.; Kumar, Mukul

    2010-03-16

    Difficult nucleation of {beta}-Sn during solidification of tin and tin-based lead-free solder alloys can result in high degrees of undercooling of the liquid prior to solidification. The undercooling can produce solder joints with large grains, anisotropic behavior, and undesirable mechanical properties. This paper describes our examination of the amount of undercooling of tin on both graphite (non-wetting) and copper (wetting) surfaces using in situ x-ray diffraction. The microstructure was further characterized by optical microscopy, scanning electron microscopy, and electron backscattering diffraction imaging microscopy. Undercoolings as high as 61 C were observed for Sn solidified on graphite, while lower undercoolings, up to 30 C, were observed for Sn solidified on copper. The microstructure of the high purity Sn sample solidified on graphite showed very few grains in the cross-section, while the commercially pure Sn sample solidified with only one grain and was twinned. Tin solidified on copper contained significant amounts of copper in the tin, intermetallic phase formation at the interface, and a eutectic microstructure.

  14. Microstructure and in situ observation of undercooling for nucleation of b-Sn relevant to lead-free solder alloys

    SciTech Connect

    Elmer, J. W.; Specht, Eliot D; Kumar, Mukul

    2010-01-01

    Difficult nucleation of b-Sn during solidification of tin and tin-based lead-free solder alloys can result in high degrees of undercooling of the liquid prior to solidification. The undercooling can produce solder joints with large grains, anisotropic behavior, and undesirable mechanical properties. This paper describes our examination of the amount of undercooling of tin on both graphite (non-wetting) and copper (wetting) surfaces using in situ x-ray diffraction. The microstructure was further characterized by optical microscopy, scanning electron microscopy, and electron backscattering diffraction imaging microscopy. Undercoolings as high as 61C were observed for Sn solidified on graphite, while lower undercoolings, up to 30C, were observed for Sn solidified on copper. The microstructure of the high purity Sn sample solidified on graphite showed very few grains in the cross-section, while the commercially pure Sn sample solidified with only one grain and was twinned. Tin solidified on copper contained significant amounts of copper in the tin, intermetallic phase formation at the interface, and a eutectic microstructure.

  15. On the Mutual Effect of Viscoplasticity and Interfacial Damage Progression in Interfacial Fracture of Lead-Free Solder Joints

    NASA Astrophysics Data System (ADS)

    Maleki, Milad; Cugnoni, Joel; Botsis, John

    2011-10-01

    The main goal of this paper is to shed light on the effect of strain rate and viscoplastic deformation of bulk solder on the interfacial failure of lead-free solder joints. For this purpose, interfacial damage evolution and mode I fracture behavior of the joint were evaluated experimentally by performing stable fracture tests at different strain rates employing an optimized tapered double cantilever beam (TDCB) design. The viscoplastic behavior of the solder was characterized in shear, and the constitutive parameters related to the Anand model were determined. A rate-independent cohesive zone damage model was identified to best simulate the interfacial damage progression in the TDCB tests by developing a three-dimensional (3D) finite-element (FE) model and considering the viscoplastic response of the bulk solder. The influence of strain rate on the load capability and failure mode of the joint was clarified by analyzing the experimental and simulation results. It was shown how, at the lower strain rates, the normal stress generated at the interface is limited by the significant creep relaxation developed in the bulk solder and thus is not sufficiently high to initiate interfacial damage, whereas at higher rates, a large amount of the external energy is dissipated into interfacial damage development.

  16. Crystal Plasticity Finite-Element Analysis of Deformation Behavior in Multiple-Grained Lead-Free Solder Joints

    NASA Astrophysics Data System (ADS)

    Darbandi, P.; Bieler, T. R.; Pourboghrat, F.; Lee, Tae-kyu

    2013-02-01

    The elastic and plastic anisotropy of the tin phase in a Pb-free tin-based solder joint has a very important effect on the reliability of solder joints. The crystal plasticity finite-element (CPFE) method takes into account the effect of anisotropy, and it can be used to solve crystal mechanical deformation problems under complicated external and internal boundary conditions imposed by inter- and intragrain micromechanical interactions. In this study, experimental lap-shear test results from the literature are used to calibrate the CPFE model. The spatial neighbor orientation relationships of the crystals were assessed by studying four different sets of orientations using a very simple model to establish a basis for further development of the model. Average shear strain and Schmid factor analyses were applied to study the activity of slip systems. Further optimization of model parameters using comparisons with experiments will be needed to identify more suitable rules for stress evolution among the 10 slip systems in Sn. By suppression of some of the slip systems the CPFE model is able to simulate heterogeneous deformation phenomena that are similar to those observed in experiments. This work establishes a basis for an incremental model development strategy based upon experiments, modeling, and comparative analysis to establish model parameters that could predict the slip processes that lead to damage evolution in lead-free solder joints.

  17. Mechanical Characterization of Lead-Free Sn-Ag-Cu Solder Joints by High-Temperature Nanoindentation

    NASA Astrophysics Data System (ADS)

    Lotfian, S.; Molina-Aldareguia, J. M.; Yazzie, K. E.; Llorca, J.; Chawla, N.

    2013-06-01

    The reliability of Pb-free solder joints is controlled by their microstructural constituents. Therefore, knowledge of the solder microconstituents' mechanical properties as a function of temperature is required. Sn-Ag-Cu lead-free solder alloy contains three phases: a Sn-rich phase, and the intermetallic compounds (IMCs) Cu6Sn5 and Ag3Sn. Typically, the Sn-rich phase is surrounded by a eutectic mixture of ?-Sn, Cu6Sn5, and Ag3Sn. In this paper, we report on the Young's modulus and hardness of the Cu6Sn5 and Cu3Sn IMCs, the ?-Sn phase, and the eutectic compound, as measured by nanoindentation at elevated temperatures. For both the ?-Sn phase and the eutectic compound, the hardness and Young's modulus exhibited strong temperature dependence. In the case of the intermetallics, this temperature dependence is observed for Cu6Sn5, but the mechanical properties of Cu3Sn are more stable up to 200C.

  18. Compatibility of lead-free solders with lead containing surface finishes as a reliability issue in electronic assemblies

    SciTech Connect

    Vianco, P.; Rejent, J.; Artaki, I.; Ray, U.; Finley, D.; Jackson, A.

    1996-03-01

    Enhanced performance goals and environmental restrictions have heightened the consideration for use of alternative solders as replacements for the traditional tin-lead (Sn-Pb) eutectic and near-eutectic alloys. However, the implementation of non-Pb bearing surface finishes may lag behind solder alloy development. A study was performed which examined the effect(s) of Pb contamination on the performance of Sn-Ag-Bi and Sn-Ag-Cu-Sb lead-free solders by the controlled addition of 63Sn-37Pb solder at levels of 0.5 {minus} 8.0 wt.%. Thermal analysis and ring-in-plug shear strength studies were conducted on bulk solder properties. Circuit board prototype studies centered on the performance of 20I/O SOIC gull wing joints. Both alloys exhibited declines in their melting temperatures with greater Sn-Pb additions. The ring-in-plug shear strength of the Sn-Ag-Cu-Sb solder increased slightly with Sn-Pb levels while the Sn-Ag-Bi alloy experienced a strength loss. The mechanical behavior of the SOIC (Small Outline Integrated Circuit) Sn-Ag-Bi solder joints reproduced the strength levels were insensitive to 10,106 thermal cycles. The Sn-Ag-Cu-Sb solder showed a slight decrease in the gull wing joint strengths that was sensitive to the Pb content of the surface finish.

  19. Size Control and Characterization of Sn-Ag-Cu Lead-Free Nanosolders by a Chemical Reduction Process

    NASA Astrophysics Data System (ADS)

    Yung, K. C.; Law, C. M. T.; Lee, C. P.; Cheung, B.; Yue, T. M.

    2012-02-01

    Sn-3.0Ag-0.5Cu nanosolders were synthesized via a chemical reduction method. Polyvinyl pyrrolidone (PVP) and sodium borohydride (NaBH4) were employed as surfactant and reducing agent, respectively. Ultraviolet-visible (UV-visible) absorption and x-ray diffraction patterns revealed that alloying had successfully taken place during the reduction process. Different amounts of PVP and NaBH4 additions influenced the nanosolder particle size. Under varying reaction temperatures and pH values, various ranges of nanosolder size were obtained. Optimized nanosolders were studied by differential scanning calorimetry to investigate the depression of the melting temperature, and were analyzed by transmission electron microscopy to measure actual particle sizes. The dependence of the particle size on the melting temperature was observed. The melting point was depressed to 204.4C when the average diameter of the nanosolders was 20 nm. Although SnO2 was formed on the nanosolders, it could be cleaned by citric acid. These low-melting-temperature Sn-Ag-Cu nanosolders are candidates for use in lead-free interconnect applications.

  20. Effect of Interfacial Reactions on the Reliability of Lead-Free Assemblies after Board Level Drop Tests

    NASA Astrophysics Data System (ADS)

    Xia, Yanghua; Lu, Chuanyan; Xie, Xiaoming

    2007-09-01

    The reliability of lead-free electronic assemblies after board level drop tests was investigated. Thin small outline package (TSOP) components with 42 FeNi alloy leads were reflow soldered on FR4 printed circuit boards (PCBs) with Sn3.0Ag0.5Cu (wt%) solder. The effects of different PCB finishes [organic solderability preservative (OSP) and electroless nickel immersion gold (ENIG)], multiple reflow (once and three times), and isothermal aging (500 h at 125C after one time reflow) were studied. The ENIG finish showed better performance than its OSP counterparts. With the OSP finish, solder joints reflowed three times showed obvious improvement compared to those of the sample reflowed once, while aging led to apparent degradation. The results showed that intermetallic compound (IMC) types, IMC microstructure and solder microstructure compete with each other, all playing very important roles in the solder joint lifetime. The results also showed that it is important to specify adequate conditions for a given reliability assessment program, to allow meaningful comparison between results of different investigators.

  1. Methodology for analyzing stress states during in-situ thermomechanical cycling in individual lead free solder joints using synchrotron radiation

    SciTech Connect

    Zhou, Bite; Bieler, Thomas R.; Lee , Tae-Kyu; Liu, Kuo-Chuan

    2010-07-22

    To examine how a lead-free solder joint deforms in a thermal cycling environment, both the elastic and plastic stress and strain behavior must be understood. Methods to identify evolution of the internal strain (stress) state during thermal cycling are described. A slice of a package containing a single row of solder joints was thermally cycled from 0 C to 100 C with a period of about 1 h with concurrent acquisition of transmission Laue patterns using synchrotron radiation. These results indicated that most joints are single crystals, with some being multicrystals with no more than a few Sn grain orientations. Laue patterns were analyzed to estimate local strains in different crystal directions at different temperatures during a thermal cycle. While the strains perpendicular to various crystal planes all vary in a similar way, the magnitude of strain varies. The specimens were subsequently given several hundred additional thermal cycles and measured again to assess changes in the crystal orientations. These results show that modest changes in crystal orientations occur during thermal cycling.

  2. Thermomechanical Fatigue Performance of Lead-Free Chip Scale Package Assemblies with Fast Cure and Reworkable Capillary Flow Underfills

    NASA Astrophysics Data System (ADS)

    Shi, Hongbin; Tian, Cuihua; Ueda, Toshitsugu

    2012-05-01

    In this paper, we present the results of temperature cycling test for full and partial capillary flow underfilled lead-free chip scale packages (CSPs), the tests were carried out on the basis of JEDEC standard. Two kinds of representative fast cure and reworkable underfill materials are used in this study, and CSPs without underfills were also tested for comparison. The test results show that the two underfill materials reduce the thermomechanical fatigue performance of CSP assemblies. The underfill with high Tg and storage modulus yielded better performance; indeed, the coefficient of thermal expansion (CTE) is also very critical to the thermomechanical fatigue performance, but its effects is not so obvious in this study owing to the similar CTEs of the underfills used. In addition, the negative effect of a partial underfill pattern is smaller than that of a full underfill pattern. Failure analysis shows that the dominant failure mode observed is solder cracking near the package and/or printed circuit board pads.

  3. Upconversion luminescence, ferroelectrics and piezoelectrics of Er Doped SrBi4Ti4O15

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

    Er3+ doped SrBi4Ti4O15 (SBT) bismuth layered-structure ferroelectric ceramics were synthesized by the traditional solid-state method, and their upconversion photoluminescent (UC) properties were investigated as a function of Er3+ concentration and incident pump power. Green (555 nm) and red (670 nm) emission bands were obtained under 980 nm excitation at room temperature, which corresponded to the radiative transitions from 4S3/2, and 4F9/2 to 4I15/2, respectively. The emission color of the samples could be changed with moderating the doping concentrations. The dependence of UC intensity on pumping power indicated a two-photon emission process. Studies on dielectric properties indicated that the introduction of Er increased the ferroelectric-paraelectric phase transition temperature (Tc) of SBT, thus making this ceramic suitable for piezoelectric sensor applications at higher temperatures. Piezoelectric measurement showed that the doped SBT had a relative higher piezoelectric constant d33 compared with the non-doped ceramics. The thermal annealing behaviors of the doped sample revealed a stable piezoelectric property. The doped SBT showed bright UC emission while simultaneously having increased Tc and d33. As a multifunctional material, Er doped SBT ferroelectric oxide showed great potential in application of sensor, future optical-electro integration and coupling devices.

  4. Facilitating NASA's Use of GEIA-STD-0005-1, Performance Standard for Aerospace and High Performance Electronic Systems Containing Lead-Free Solder

    NASA Technical Reports Server (NTRS)

    Plante, Jeannete

    2010-01-01

    GEIA-STD-0005-1 defines the objectives of, and requirements for, documenting processes that assure customers and regulatory agencies that AHP electronic systems containing lead-free solder, piece parts, and boards will satisfy the applicable requirements for performance, reliability, airworthiness, safety, and certify-ability throughout the specified life of performance. It communicates requirements for a Lead-Free Control Plan (LFCP) to assist suppliers in the development of their own Plans. The Plan documents the Plan Owner's (supplier's) processes, that assure their customer, and all other stakeholders that the Plan owner's products will continue to meet their requirements. The presentation reviews quality assurance requirements traceability and LFCP template instructions.

  5. High-Temperature Piezoelectric Sensing

    PubMed Central

    Jiang, Xiaoning; Kim, Kyungrim; Zhang, Shujun; Johnson, Joseph; Salazar, Giovanni

    2014-01-01

    Piezoelectric sensing is of increasing interest for high-temperature applications in aerospace, automotive, power plants and material processing due to its low cost, compact sensor size and simple signal conditioning, in comparison with other high-temperature sensing techniques. This paper presented an overview of high-temperature piezoelectric sensing techniques. Firstly, different types of high-temperature piezoelectric single crystals, electrode materials, and their pros and cons are discussed. Secondly, recent work on high-temperature piezoelectric sensors including accelerometer, surface acoustic wave sensor, ultrasound transducer, acoustic emission sensor, gas sensor, and pressure sensor for temperatures up to 1,250 C were reviewed. Finally, discussions of existing challenges and future work for high-temperature piezoelectric sensing are presented. PMID:24361928

  6. Evaluation of polarization of embedded piezoelectrics by the thermal wave method.

    PubMed

    Suchaneck, Gunnar; Eydam, Agnes; Hu, Wenguo; Kranz, Burkhart; Drossel, Welf-Guntram; Gerlach, Gerald

    2012-09-01

    This work demonstrates the benefit of the thermal wave method for the evaluation of the polarization state of embedded piezoelectrics. Two types of samples were investigated: A low-temperature co-fired ceramics (LTCC)/lead zirconate titanate (PZT) sensor-actuator and a macro-fiber composite (MFC) actuator. At modulation frequencies below 10 Hz, the pyroelectric response was governed by thermal losses to the embedding layers. Here, the sample behavior was described by a harmonically heated piezoelectric plate exhibiting heat losses to the environment characterized by a single thermal relaxation time. PMID:23007766

  7. Compliant Electrode and Composite Material for Piezoelectric Wind and Mechanical Energy Conversions

    NASA Technical Reports Server (NTRS)

    Chen, Bin (Inventor)

    2015-01-01

    A thin film device for harvesting energy from wind. The thin film device includes one or more layers of a compliant piezoelectric material formed from a composite of a polymer and an inorganic material, such as a ceramic. Electrodes are disposed on a first side and a second side of the piezoelectric material. The electrodes are formed from a compliant material, such as carbon nanotubes or graphene. The thin film device exhibits improved resistance to structural fatigue upon application of large strains and repeated cyclic loadings.

  8. Size effects of lead-free solder joint thickness under shear creep based on micro-electrical-resistance strain

    NASA Astrophysics Data System (ADS)

    Jiang, Li; Zhang, Guiying; Zhou, Jieming

    2008-08-01

    Single shear lap creep specimens with a 1 mm2 cross sectional area between thin copper strips were developed and fabricated using a lead-free solder (Sn-3.5Ag) to quantify their electrical resistance. The electrical-resistance strain of solder joints with different thicknesses (0.05, 0.10, 0.15, 0.20, 0.25, 0.30, 0.40, 0.50 mm) were measured by a tailor-made in situ micro-electrical-resistance measurement. The results showed that the solder joints with 0.25 mm thickness yielded a minimum electrical-resistance strain and the longest creep life. Thicker solder joints produced a larger electrical-resistance strain and a shorter lifetime if the thickness >0.25 mm. In contrast, thinner solder joints produced a larger electrical-resistance strain and a shorter lifetime if the thickness <0.25 mm. A quantificational relationship between the electrical-resistance strain and the solder joint thickness was obtained according to the experimental data. On the other hand, solder joints with different thicknesses (corresponding to those used in the experiment) were studied by the finite element method (FEM). The results showed that the creep strain of solder joints was the lowest with 0.25 mm thickness, and the creep strain increased with the increment in the thickness if the thickness >0.25 mm but decreased with the increment in the thickness if the thickness <0.25 mm. The quantificational relationship between the creep strain and solder joints thickness was obtained according to the data of FEM. Finally, the quantificational relationship between the creep strain and the electrical-resistance strain was obtained by combining the experimental data and the FEM data.

  9. Structural, microstructural and thermal properties of lead-free bismuthsodiumbariumtitanate piezoceramics synthesized by mechanical alloying

    SciTech Connect

    Amini, Rasool; Ghazanfari, Mohammad Reza; Alizadeh, Morteza; Ardakani, Hamed Ahmadi; Ghaffari, Mohammad

    2013-02-15

    Graphical abstract: Mechano-synthesis of lead-free (Bi{sub 0.5}Na{sub 0.5}){sub 0.94}Ba{sub 0.06}TiO{sub 3} piezoceramics with nanocrystalline/amorphous structure and homogeneous composition: partial transformation of constituents to BNBT, BNT and pyrochlore, amorphous phase formation, mechano-crystallization of the amorphous, pyrochlore-to-perovskite BNBT phase transformation during the process. Display Omitted Highlights: ? Perovskite BNBT powders with homogeneous composition were synthesized by MA. ? Partial transformation of constituents to BNBT, BNT and pyrochlore occurred by MA. ? Formation of an amorphous phase and afterwards its crystallization occurred by MA. ? Pyrochlore-to-perovskite BNBT phase transformation occurred after prolong milling. ? Polymorphic transformations of TiO{sub 2} act as the main alloying impediment during MA. -- Abstract: Bismuthsodiumbariumtitanate piezoceramics with a composition of (Bi{sub 0.5}Na{sub 0.5}){sub 0.94}Ba{sub 0.06}TiO{sub 3} (BNBT) were prepared by mechanical alloying (MA). Structural analysis and phase identification were performed by X-ray diffraction (XRD). Microstructural studies and chemical composition homogeneity were performed by scanning electron microscope (SEM) coupled with energy dispersive X-ray analysis (EDX). Furthermore, thermal properties of the as-milled powders were evaluated by thermogravimetry/differential thermal analysis (TG/DTA). During the initial milling, the constituents were transformed to the perovskite, pyrochlore, and BNT phases; in addition, partial amorphization of the structure appeared during the milling cycle. As MA progressed, transformation of pyrochlore-to-perovskite and crystallization of the amorphous phase occurred and also, the BNBT phase was significantly developed. It was found that the MA process has the ability to synthesize the BNBT powders with a submicron particle size, regular morphology, and uniform elemental distribution.

  10. 2011201120112011 2011 Symposium on Piezoelectricity, Acoustic waves, and Device Application

    E-print Network

    Chen, Baoquan

    of Piezoelectric Devices; Oscillators and Filters; Ultrasound Imaging, drug delivery and Therapy; (, ) Kirk; MEMS/NEMS/Nano Piezoelectric Devices; Piezoelectric Materials; Ultrasonics; Manufacturing Technology

  11. Asymmetric electrode design for significant performance enhancement of piezoelectric P(VDF-TrFE) polymer microcantilevers

    NASA Astrophysics Data System (ADS)

    Oh, Sharon Roslyn; Yao, Kui; Zhang, Lei; Eng Hock Tay, Francis

    2015-04-01

    A concept of utilizing asymmetric electrode structures for significantly enhancing the performance of piezoelectric polymer microelectromechanical systems is proposed. Piezoelectric poly(vinyl difluoride-trifluoroethylene) (P(VDF-TrFE)) polymer micro unimorph cantilevers with different thicknesses of the top and bottom metallic electrodes are designed and investigated. Both the analytical calculations and finite element simulations show that a large shift of the neutral axis away from the center of the active piezoelectric P(VDF-TrFE) layer can be realized by the adoption of top and bottom metallic electrodes with different thicknesses. The neutral axis shift due to the asymmetric electrode thicknesses is greater for piezoelectric polymer materials due to the lower Youngs moduli. It was shown that superior performance could even be achievable with a softer P(VDF-TrFE) cantilever with asymmetric electrode thicknesses over a cantilever using a piezoelectric ceramic layer with a much stronger piezoelectric effect. The feasibility of fabricating the P(VDF-TrFE) polymer micro cantilevers with asymmetric electrode thicknesses was demonstrated with a surface micromachining process.

  12. Development of Piezoelectric Thin Film Resonator and Its Impact on Future Wireless Communication Systems

    NASA Astrophysics Data System (ADS)

    Satoh, Yoshio; Nishihara, Tokihiro; Yokoyama, Tsuyoshi; Ueda, Masanori; Miyashita, Tsutomu

    2005-05-01

    The bulk acoustic wave filter composed of piezoelectric thin film resonators has many features superior to those of other small filters such as a surface acoustic wave (SAW) filter and a ceramic filter. As it has no fine structure in its electrode design, it has a high Q factor that leads to low-loss and sharp-cut off characteristics and a high power durability particularly in the high-frequency range. Furthermore, it has the potentiality of integrated devices on a Si substrate. In this paper, we review the recent developments of piezoelectric thin film resonator filters in the world, including our development for mobile communication applications. After describing the feature and history of the piezoelectric thin film resonator filters, our technologies are introduced in focusing on the resonator structures, the piezoelectric thin film and electrode film materials, the cavity structures, the filter structure and its design rules and characteristics, comparing with SAW filters. The competition and coexistence between the piezoelectric thin film resonator filters and the SAW filters are also described. In this paper, we describe the development of a piezoelectric thin film resonator from the standpoint of researchers who have a long experience of SAW filter development.

  13. Piezoelectric motor development at AlliedSignal Inc., Kansas City Division

    SciTech Connect

    Pressly, R.B.; Mentesana, C.P.

    1994-11-01

    The Kansas City Division of AlliedSignal Inc. has been investigating the fabrication and use of piezoelectric motors in mechanisms for United States Department of Energy (DOE) weapons applications for about four years. These motors exhibit advantages over solenoids and other electromagnetic actuators. Prototype processes have been developed for complete fabrication of motors from stock materials, including abrasive machining of piezoelectric ceramics and more traditional machining of other motor components, electrode plating and sputtering, electric poling, cleaning, bonding and assembly. Drive circuits have been fabricated and motor controls are being developed. Laboratory facilities have been established for electrical/mechanical testing and evaluation of piezo materials and completed motors. Recent project efforts have focused on the potential of piezoelectric devices for commercial and industrial use. A broad range of various motor types and application areas has been identified, primarily in Japan. The Japanese have been developing piezo motors for many years and have more recently begun commercialization. Piezoelectric motor and actuator technology is emerging in the United States and quickly gaining in commercial interest. The Kansas City Division is continuing development of piezoelectric motors and actuators for defense applications while supporting and participating in the commercialization of piezoelectric devices with private industry through various technology transfer and cooperative development initiatives.

  14. Design Requirements for Amorphous Piezoelectric Polymers

    NASA Technical Reports Server (NTRS)

    Ounaies, Z.; Young, J. A.; Harrison, J. S.

    1999-01-01

    An overview of the piezoelectric activity in amorphous piezoelectric polymers is presented. The criteria required to render a polymer piezoelectric are discussed. Although piezoelectricity is a coupling between mechanical and electrical properties, most research has concentrated on the electrical properties of potentially piezoelectric polymers. In this work, we present comparative mechanical data as a function of temperature and offer a summary of polarization and electromechanical properties for each of the polymers considered.

  15. Piezoelectric axial flow microvalve

    DOEpatents

    Gemmen, Randall; Thornton, Jimmy; Vipperman, Jeffrey S.; Clark, William W.

    2007-01-09

    This invention is directed to a fuel cell operable with a quantity of fuel and a quantity of an oxidizer to produce electrical power, the fuel cell including a fuel cell body including a labyrinth system structured to permit the fuel and the oxidizer to flow therethrough; at least a first catalyst in fluid communication with the labyrinth; and at least a first microvalve operably disposed within at least a portion of the labyrinth. The microvalve utilizes a deflectable member operable upon the application of a voltage from a voltage source. The microvalve includes an elongated flow channel formed therein and extending substantially longitudinally between the first and second ends to permit substantially longitudinal flow of the fluid therethrough and between the first and second ends; and the deflectable member disposed on the valve body, the deflectable member including at least a first piezoelectric portion that is piezoelectrically operable to deflect the deflectable member between an open position and a closed position upon the application of a voltage, the deflectable member in the closed position being operable to resist the flow of the fluid through the flow channel.

  16. Design and fabrication of lanthanum-doped tin-silver-copper lead-free solder for the next generation of microelectronics applications in severe environment

    NASA Astrophysics Data System (ADS)

    Sadiq, Muhammad

    Tin-Lead solder (Sn-Pb) has long been used in the Electronics industry. But, due to its toxic nature and environmental effects, certain restrictions are made on its use by the European Rehabilitation of Hazardous Substances (RoHS) directive, and therefore, many researchers are looking to replace it. The urgent need for removing lead from solder alloys led to the very fast introduction of lead-free solder alloys without a deep knowledge of their behavior. Therefore, an extensive knowledge and understanding of the mechanical behavior of the emerging generation of lead-free solders is required to satisfy the demands of structural reliability. Sn-Ag-Cu (SAC) solders are widely used as lead-free replacements but their coarse microstructure and formation of hard and brittle Inter-Metallic Compounds (IMCs) have limited their use in high temperature applications. Many additives are studied to refine the microstructure and improve the mechanical properties of SAC solders including iron (Fe), bismuth (Bi), antimony (Sb) and indium (In) etc. Whereas many researchers studied the impact of novel rare earth (RE) elements like lanthanum (La), cerium (Ce) and lutetium (Lu) on SAC solders. These RE elements are known as vitamins of metals because of their special surface active properties. They reduce the surface free energy, refine the grain size and improve the mechanical properties of many lead free solder alloys like Sn-Ag, Sn-Cu and SAC but still a systematic study is required to explore the special effects of La on the eutectic SAC alloys. The objective of this PhD thesis is to extend the current knowledge about lead free solders of SAC alloys towards lanthanum doping with varying environmental conditions implemented during service. This thesis is divided into six main parts.

  17. Dielectric Properties of Piezoelectric Polyimides

    NASA Technical Reports Server (NTRS)

    Ounaies, Z.; Young, J. A.; Simpson, J. O.; Farmer, B. L.

    1997-01-01

    Molecular modeling and dielectric measurements are being used to identify mechanisms governing piezoelectric behavior in polyimides such as dipole orientation during poling, as well as degree of piezoelectricity achievable. Molecular modeling on polyimides containing pendant, polar nitrile (CN) groups has been completed to determine their remanent polarization. Experimental investigation of their dielectric properties evaluated as a function of temperature and frequency has substantiated numerical predictions. With this information in hand, we are then able to suggest changes in the molecular structures, which will then improve upon the piezoelectric response.

  18. High piezoelectric properties of cement piezoelectric composites containing kaolin

    NASA Astrophysics Data System (ADS)

    Pan, Huang Hsing; Yang, Ruei-Hao; Cheng, Yu-Chieh

    2015-04-01

    To obtain high piezoelectric properties, PZT/cement composites with kaolin were fabricated and polarized by 1.5kV/mm electric field for 40 min, where lead zirconate titanate (PZT) inclusion with 50% by volume was used. After the polarization, piezoelectric properties of the composite were measured daily till 100 days. Results indicated that relative dielectric constant (?r) and piezoelectric strain constant (d33) increase with aging day, and approach to asymptotic values after 70 days. Temperature treatment to the composite is a dominate factor to enhance piezoelectric properties. The d33 and ?r values of PZT/cement composites treated at the ambient temperature (23?) were 57pC/N and 275 at the 70th aging day respectively, and then reached 106pC/N and 455 in turn with 150? treatment. The composite contains 4% kaolin having the highest value of d33=111pC/N and ?r=500 at 90 days because the porosity is the less than the others. Cement piezoelectric composites containing kaolin own the higher d33 and ?r value, compared with the other reported composites with 50% PZT. The porosity, the electromechanical coupling factor and impedance-frequency spectra of the cement piezoelectric composites were also discussed.

  19. Piezoelectric MEMS for energy harvesting

    E-print Network

    Kim, Sang-Gook

    Piezoelectric microelectromechanical systems (MEMS) have been proven to be an attractive technology for harvesting small magnitudes of energy from ambient vibrations. This technology promises to eliminate the need for ...

  20. Piezoelectric Rotary Tube Motor

    NASA Technical Reports Server (NTRS)

    Fisher, Charles D.; Badescu, Mircea; Braun, David F.; Culhane, Robert

    2011-01-01

    A custom rotary SQUIGGLE(Registered TradeMark) motor has been developed that sets new benchmarks for small motor size, high position resolution, and high torque without gear reduction. Its capabilities cannot be achieved with conventional electromagnetic motors. It consists of piezoelectric plates mounted on a square flexible tube. The plates are actuated via voltage waveforms 90 out of phase at the resonant frequency of the device to create rotary motion. The motors were incorporated into a two-axis postioner that was designed for fiber-fed spectroscopy for ground-based and space-based projects. The positioner enables large-scale celestial object surveys to take place in a practical amount of time.

  1. Superior piezoelectric composite films: taking advantage of carbon nanomaterials.

    PubMed

    Saber, Nasser; Araby, Sherif; Meng, Qingshi; Hsu, Hung-Yao; Yan, Cheng; Azari, Sara; Lee, Sang-Heon; Xu, Yanan; Ma, Jun; Yu, Sirong

    2014-01-31

    Piezoelectric composites comprising an active phase of ferroelectric ceramic and a polymer matrix have recently found numerous sensory applications. However, it remains a major challenge to further improve their electromechanical response for advanced applications such as precision control and monitoring systems. We here investigated the incorporation of graphene platelets (GnPs) and multi-walled carbon nanotubes (MWNTs), each with various weight fractions, into PZT (lead zirconate titanate)/epoxy composites to produce three-phase nanocomposites. The nanocomposite films show markedly improved piezoelectric coefficients and electromechanical responses (50%) besides an enhancement of ~200% in stiffness. The carbon nanomaterials strengthened the impact of electric field on the PZT particles by appropriately raising the electrical conductivity of the epoxy. GnPs have been proved to be far more promising in improving the poling behavior and dynamic response than MWNTs. The superior dynamic sensitivity of GnP-reinforced composite may be caused by the GnPs' high load transfer efficiency arising from their two-dimensional geometry and good compatibility with the matrix. The reduced acoustic impedance mismatch resulting from the improved thermal conductance may also contribute to the higher sensitivity of GnP-reinforced composite. This research pointed out the potential of employing GnPs to develop highly sensitive piezoelectric composites for sensing applications. PMID:24398819

  2. Superior piezoelectric composite films: taking advantage of carbon nanomaterials

    NASA Astrophysics Data System (ADS)

    Saber, Nasser; Araby, Sherif; Meng, Qingshi; Hsu, Hung-Yao; Yan, Cheng; Azari, Sara; Lee, Sang-Heon; Xu, Yanan; Ma, Jun; Yu, Sirong

    2014-01-01

    Piezoelectric composites comprising an active phase of ferroelectric ceramic and a polymer matrix have recently found numerous sensory applications. However, it remains a major challenge to further improve their electromechanical response for advanced applications such as precision control and monitoring systems. We here investigated the incorporation of graphene platelets (GnPs) and multi-walled carbon nanotubes (MWNTs), each with various weight fractions, into PZT (lead zirconate titanate)/epoxy composites to produce three-phase nanocomposites. The nanocomposite films show markedly improved piezoelectric coefficients and electromechanical responses (50%) besides an enhancement of 200% in stiffness. The carbon nanomaterials strengthened the impact of electric field on the PZT particles by appropriately raising the electrical conductivity of the epoxy. GnPs have been proved to be far more promising in improving the poling behavior and dynamic response than MWNTs. The superior dynamic sensitivity of GnP-reinforced composite may be caused by the GnPs high load transfer efficiency arising from their two-dimensional geometry and good compatibility with the matrix. The reduced acoustic impedance mismatch resulting from the improved thermal conductance may also contribute to the higher sensitivity of GnP-reinforced composite. This research pointed out the potential of employing GnPs to develop highly sensitive piezoelectric composites for sensing applications.

  3. [Extracorporeal piezoelectric lithotripsy of intra- and extrahepatic bile duct stones].

    PubMed

    Adamek, H E; Buttmann, A; Hartmann, C M; Jakobs, R; Riemann, J F

    1993-07-23

    64 patients (27 men, 37 women; mean age 71 [27-90] years) with intra- or extrahepatic biliary stones, which could not be extracted endoscopically, underwent extracorporeal piezoelectric shock-wave lithotripsy (ESWL). The piezoelectric lithotripter which was used localizes the stones sonographically and the shock-waves are produced by a self-focusing sound generator consisting of 3,000 ceramic elements. The sonographic localization of the stones was successful in 57 patients (89%) and complete removal of stones was achieved in 49 (77%), after an average of 7,595 (1,000-30,800) shock-waves per patient. Spontaneous elimination of stone fragments occurred in 7 patients, while in 42 further endoscopic procedures (balloon catheter, Dormia basket, mechanical lithotripsy) were needed to remove stone fragments from the biliary tract. The only severe complication was cholangitis in two cases. It probably resulted from the associated lysis treatment. There was no case of pancreatitis and no death at 30 days. These data indicate that piezoelectric ESWL with sonographic stone localization is an effective method with few side effects for treating problematic biliary tract stones. PMID:8330506

  4. Static deflection control of flexible beams by piezo-electric actuators

    NASA Technical Reports Server (NTRS)

    Baz, A. M.

    1986-01-01

    This study deals with the utilization of piezo-electric actuators in controlling the static deformation of flexible beams. An optimum design procedure is presented to enable the selection of the optimal location, thickness and excitation voltage of the piezo-electric actuators in a way that would minimize the deflection of the beam to which these actuators are bonded. Numerical examples are presented to illustrate the application of the developed optimization procedure in minimizing the structural deformation of beams of different materials when subjected to different loading and end conditions using ceramic or polymeric piezo-electric actuators. The results obtained emphasize the importance of the devised rational procedure in designing beam-actuator systems with minimal elastic distortions.

  5. Ultra-flexible Piezoelectric Devices Integrated with Heart to Harvest the Biomechanical Energy.

    PubMed

    Lu, Bingwei; Chen, Ying; Ou, Dapeng; Chen, Hang; Diao, Liwei; Zhang, Wei; Zheng, Jun; Ma, Weiguo; Sun, Lizhong; Feng, Xue

    2015-01-01

    Power supply for medical implantable devices (i.e. pacemaker) always challenges not only the surgery but also the battery technology. Here, we report a strategy for energy harvesting from the heart motion by using ultra-flexible piezoelectric device based on lead zirconate titanate (PZT) ceramics that has most excellent piezoelectricity in commercial materials, without any burden or damage to hearts. Experimental swine are selected for in vivo test with different settings, i.e. opened chest, close chest and awake from anesthesia, to simulate the scenario of application in body due to their hearts similar to human. The results show the peak-to-peak voltage can reach as high as 3?V when the ultra-flexible piezoelectric device is fixed from left ventricular apex to right ventricle. This demonstrates the possibility and feasibility of fully using the biomechanical energy from heart motion in human body for sustainably driving implantable devices. PMID:26538375

  6. Ultra-flexible Piezoelectric Devices Integrated with Heart to Harvest the Biomechanical Energy

    PubMed Central

    Lu, Bingwei; Chen, Ying; Ou, Dapeng; Chen, Hang; Diao, Liwei; Zhang, Wei; Zheng, Jun; Ma, Weiguo; Sun, Lizhong; Feng, Xue

    2015-01-01

    Power supply for medical implantable devices (i.e. pacemaker) always challenges not only the surgery but also the battery technology. Here, we report a strategy for energy harvesting from the heart motion by using ultra-flexible piezoelectric device based on lead zirconate titanate (PZT) ceramics that has most excellent piezoelectricity in commercial materials, without any burden or damage to hearts. Experimental swine are selected for in vivo test with different settings, i.e. opened chest, close chest and awake from anesthesia, to simulate the scenario of application in body due to their hearts similar to human. The results show the peak-to-peak voltage can reach as high as 3?V when the ultra-flexible piezoelectric device is fixed from left ventricular apex to right ventricle. This demonstrates the possibility and feasibility of fully using the biomechanical energy from heart motion in human body for sustainably driving implantable devices. PMID:26538375

  7. Monitoring the hydrolytic degradation of polyester-based composites by a piezoelectric method

    SciTech Connect

    Sainte-Pierre, N.; Perrissin, I.; Jayet, Y.; Tatiboueet, J.

    1995-10-01

    Theoretical considerations show that the electric impedance of a piezoelectric element depends on the physical and geometrical properties of the element and also on the viscoelastic characteristics of the different media surrounding it. According to a dynamic model, an original technique has been developed by inserting a piezoelectric ceramic in the composite structure when processed. The electric signal, after signal processing and numerical treatments, gives access to the viscoelastic properties of the external medium. This method is an excellent indicator to display the polymerization kinetics of the resin as well as the post-curing phase of the composite structure process. Moreover, a further application of this non-destructive method is the monitoring of the hydrolitic degradation of the composite structure. The evolution of the electric impedance of the piezoelectric sensor is presented here as a function of water exposition time for a polyester-based composite.

  8. Ultra-flexible Piezoelectric Devices Integrated with Heart to Harvest the Biomechanical Energy

    NASA Astrophysics Data System (ADS)

    Lu, Bingwei; Chen, Ying; Ou, Dapeng; Chen, Hang; Diao, Liwei; Zhang, Wei; Zheng, Jun; Ma, Weiguo; Sun, Lizhong; Feng, Xue

    2015-11-01

    Power supply for medical implantable devices (i.e. pacemaker) always challenges not only the surgery but also the battery technology. Here, we report a strategy for energy harvesting from the heart motion by using ultra-flexible piezoelectric device based on lead zirconate titanate (PZT) ceramics that has most excellent piezoelectricity in commercial materials, without any burden or damage to hearts. Experimental swine are selected for in vivo test with different settings, i.e. opened chest, close chest and awake from anesthesia, to simulate the scenario of application in body due to their hearts similar to human. The results show the peak-to-peak voltage can reach as high as 3?V when the ultra-flexible piezoelectric device is fixed from left ventricular apex to right ventricle. This demonstrates the possibility and feasibility of fully using the biomechanical energy from heart motion in human body for sustainably driving implantable devices.

  9. Structural Origins of Silk Piezoelectricity

    PubMed Central

    Yucel, Tuna; Cebe, Peggy

    2012-01-01

    Uniaxially oriented, piezoelectric silk films were prepared by a two-step method that involved: (1) air drying aqueous, regenerated silk fibroin solutions into films, and (2) drawing the silk films to a desired draw ratio. The utility of two different drawing techniques, zone drawing and water immersion drawing were investigated for processing the silk for piezoelectric studies. Silk films zone drawn to a ratio of ?= 2.7 displayed relatively high dynamic shear piezoelectric coefficients of d14 = ?1.5 pC/N, corresponding to over two orders of magnitude increase in d14 due to film drawing. A strong correlation was observed between the increase in the silk II, ?-sheet content with increasing draw ratio measured by FTIR spectroscopy (C?? e2.5 ?), the concomitant increasing degree of orientation of ?-sheet crystals detected via WAXD (FWHM = 0.22 for ?= 2.7), and the improvement in silk piezoelectricity (d14? e2.4 ?). Water immersion drawing led to a predominantly silk I structure with a low degree of orientation (FWHM = 75) and a much weaker piezoelectric response compared to zone drawing. Similarly, increasing the ?-sheet crystallinity without inducing crystal alignment, e.g. by methanol treatment, did not result in a significant enhancement of silk piezoelectricity. Overall, a combination of a high degree of silk II, ?-sheet crystallinity and crystalline orientation are prerequisites for a strong piezoelectric effect in silk. Further understanding of the structural origins of silk piezoelectricity will provide important options for future biotechnological and biomedical applications of this protein. PMID:23335872

  10. Effect of material constants on power output in piezoelectric vibration-based generators.

    PubMed

    Takeda, Hiroaki; Mihara, Kensuke; Yoshimura, Tomohiro; Hoshina, Takuya; Tsurumi, Takaaki

    2011-09-01

    A possible power output estimation based on material constants in piezoelectric vibration-based generators is proposed. A modified equivalent circuit model of the generator was built and was validated by the measurement results in the generator fabricated using potassium sodium niobate-based and lead zirconate titanate (PZT) ceramics. Subsequently, generators with the same structure using other PZT-based and bismuth-layered structure ferroelectrics ceramics were fabricated and tested. The power outputs of these generators were expressed as a linear functions of the term composed of electromechanical coupling coefficients k(sys)(2) and mechanical quality factors Q*(m) of the generator. The relationship between device constants (k(sys)(2) and Q*(m)) and material constants (k(31)(2) and Q(m)) was clarified. Estimation of the power output using material constants is demonstrated and the appropriate piezoelectric material for the generator is suggested. PMID:21937317

  11. Effect of dielectrophoretic structuring on piezoelectric and pyroelectric properties of lead titanate-epoxy composites

    NASA Astrophysics Data System (ADS)

    Khanbareh, H.; van der Zwaag, S.; Groen, W. A.

    2014-10-01

    Functional granular composites of lead titanate particles in an epoxy matrix prepared by dielectrophoresis show enhanced dielectric, piezoelectric and pyroelectric properties compared to 0-3 composites for different ceramic volume content from 10% to 50%. Two structuring parameters, the interparticle distance and the percentage of 1-3 connectivity are used based on the Bowen model and the mixed connectivity model respectively. The degree of structuring calculated according to both models correlate well with the increase in piezoelectric and pyroelectric sensitivities of the composites. Higher sensitivity of the electroactive properties are observed at higher ceramic volume fractions. The effect of electrical conductivity of the matrix on the pyroelectric responsivity of the composites has been demonstrated to be a key parameter in governing the pyroelectric properties of the composites.

  12. Performance of Integrated Fiber Optic, Piezoelectric, and Shape Memory Alloy Actuators/Sensors in Thermoset Composites

    NASA Technical Reports Server (NTRS)

    Trottier, C. Michael

    1996-01-01

    Recently, scientists and engineers have investigated the advantages of smart materials and structures by including actuators in material systems for controlling and altering the response of structural environments. Applications of these materials systems include vibration suppression/isolation, precision positioning, damage detection and tunable devices. Some of the embedded materials being investigated for accomplishing these tasks include piezoelectric ceramics, shape memory alloys, and fiber optics. These materials have some benefits and some shortcomings; each is being studied for use in active material design in the SPICES (Synthesis and Processing of Intelligent Cost Effective Structures) Consortium. The focus of this paper concerns the manufacturing aspects of smart structures by incorporating piezoelectric ceramics, shape memory alloys and fiber optics in a reinforced thermoset matrix via resin transfer molding (RTM).

  13. A study of the temperature dependence of the local ferroelectric properties of c-axis oriented Bi6Ti3Fe2O18 Aurivillius phase thin films: Illustrating the potential of a novel lead-free perovskite material for high density memory applications

    NASA Astrophysics Data System (ADS)

    Faraz, Ahmad; Deepak, Nitin; Schmidt, Michael; Pemble, Martyn E.; Keeney, Lynette

    2015-08-01

    The ability to control the growth, texture and orientation of self-nanostructured lead-free Aurivillius phase thin films can in principle, greatly improve their ferroelectric properties, since in these materials the polarization direction is dependent on crystallite orientation. Here, we report the growth of c-plane oriented Bi6Ti3Fe2O18 (B6TFO) functional oxide Aurivillius phase thin films on c-plane sapphire substrates by liquid injection chemical vapour deposition (LI-CVD). Microstructural analysis reveals that B6TFO thin films annealed at 850C are highly crystalline, well textured (Lotgering factor of 0.962) and single phase. Typical Aurivillius plate-like morphology with an average film thickness of 110nm and roughness 24nm was observed. The potential of B6TFO for use as a material in lead-free piezoelectric and ferroelectric data storage applications was explored by investigating local electromechanical (piezoelectric) and ferroelectric properties at the nano-scale. Vertical and lateral piezoresponse force microscopy (PFM) reveals stronger in-plane polarization due to the controlled growth of the a-axis oriented grains lying in the plane of the B6TFO films. Switching spectroscopy PFM (SS-PFM) hysteresis loops obtained at higher temperatures (up to 200C) and at room temperature reveal a clear ferroelectric signature with only minor changes in piezoresponse observed with increasing temperature. Ferroelectric domain patterns were written at 200C using PFM lithography. Hysteresis loops generated inside the poled regions at room and higher temperatures show a significant increase in piezoresponse due to alignment of the c-axis polarization components under the external electric field. No observable change in written domain patterns was observed after 20hrs of PFM scanning at 200C, confirming that B6TFO retains polarization over this finite period of time. These studies demonstrate the potential of B6TFO thin films for use in piezoelectric applications at elevated temperatures and for use in non-volatile ferroelectric memory applications.

  14. Piezoelectric activity in Perovskite ferroelectric crystals.

    PubMed

    Li, Fei; Wang, Linghang; Jin, Li; Lin, Dabin; Li, Jinglei; Li, Zhenrong; Xu, Zhuo; Zhang, Shujun

    2015-01-01

    Perovskite ferroelectrics (PFs) have been the dominant piezoelectric materials for various electromechanical applications, such as ultrasonic transducers, sensors, and actuators, to name a few. In this review article, the development of PF crystals is introduced, focusing on the crystal growth and piezoelectric activity. The critical factors responsible for the high piezoelectric activity of PFs (i.e., phase transition, monoclinic phase, domain size, relaxor component, dopants, and piezoelectric anisotropy) are surveyed and discussed. A general picture of the present understanding on the high piezoelectricity of PFs is described. At the end of this review, potential approaches to further improve the piezoelectricity of PFs are proposed. PMID:25585387

  15. Shear piezoelectricity of optically active polysuccinimides

    NASA Astrophysics Data System (ADS)

    Tanimoto, Kazuhiro; Saihara, Shota; Adachi, Yu; Harada, Yuhei; Shiomi, Yuki; Tajitsu, Yoshiro

    2015-10-01

    Optically active crystalline polymers have shear piezoelectricity owing to their asymmetric crystal structure. In this study, to explore a novel shear piezoelectric polymer, we have focused on an imide ring structure and synthesized optically active polysuccinimides (PSIs), the minimum structure of optically active polyimides. As a result, optically active PSIs were obtained, and we observed that oriented optically active PSI films show shear piezoelectricity. Furthermore, both optical purity and molecular weight are significant factors in piezoelectric performance. This is the first report of the shear piezoelectricity of optically active polyimides, and we identify herein a novel category of a shear piezoelectric polymer.

  16. Development of piezoelectric skin friction force vector transducer for a hypersonic wind tunnel

    NASA Technical Reports Server (NTRS)

    Kahng, S. K.

    1972-01-01

    A surface shear force transducer for use in impulse type hypersonic tunnels is described. Sensors are constructed of lead zirconate titanate composition piezoelectric ceramic materials. The diameter of the sensing diaphragm is 0.75 inches and overall transducer dimensions are 1.0 inch diameter and 0.625 inch height. Analysis of the tranducer is made to help design criteria and fabrication techniques. Discussions on design and fabrication techniques are presented as well as performance of transducers delivered.

  17. Relation of the external mechanical stress to the properties of piezoelectric materials for energy harvesting

    NASA Astrophysics Data System (ADS)

    Jeong, Soon-Jong; Kim, Min-Soo; Lee, Dae-Su; Song, Jae-Sung; Cho, Kyung-Ho

    2013-12-01

    We investigated the piezoelectric properties and the generation of voltage and power under the mechanical compressive loads for three types of piezoelectric ceramics 0.2Pb(Mg1/3Nb2/3)O3-0.8Pb(Zr0.475Ti0.525)O3 (soft-PZT), 0.1Pb(Mg1/3Sb2/3)O3- 0.9Pb(Zr0.475Ti0.525)O3 (hard-PZT) and [0.675Pb(Mg1/3Nb2/3)O3-0.35PbTiO3]+5 wt% BaTiO3 (textured-PMNT). The piezoelectric d 33 coefficients of all specimens increased with increasing compressive load. The generated voltage and power showed a linear relation and square relation to the applied stress, respectively. These results were larger than those calculated using the simple piezoelectric equation due to the non-linear characteristics of the ceramics, so they were evaluated with a simple model based on a non-linear relation.

  18. Characterization of organic gunshot residues in lead-free ammunition using a new sample collection device for liquid chromatography-quadrupole time-of-flight mass spectrometry.

    PubMed

    Benito, Sandra; Abrego, Zurie; Snchez, Alicia; Unceta, Nora; Goicolea, M Aranzazu; Barrio, Ramn J

    2015-01-01

    The identification of characteristic organic gunshot residues (OGSR) provides conclusive evidence in the elucidation of elemental profiles when lead-free ammunition is fired. OGSR also prevents false negatives. Toward this aim, a quick and efficient method based on liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-QTOF) was developed to detect and identify 18 gunpowder additives in gunshot residues (GSR). The unequivocal identification of target analytes was assured by using MS/MS mode. Swabs were compared with home-modified tape lift supports covered with a PTFE layer to determine the better sampling technique. The modified tape lift provided better extraction recoveries and enabled the analysis of inorganic and organic GSR simultaneously. The developed method was applied to the analysis of GSR from four different lead-free ammunitions. Diphenylamine and its nitrated degradation products and centralites were identified in all samples, providing strong evidence of GSR. PMID:25481775

  19. Piezoelectric and pyroelectric properties of conductive polyethylene oxide-lead titanate composites

    NASA Astrophysics Data System (ADS)

    Khanbareh, H.; van der Zwaag, S.; Groen, W. A.

    2015-04-01

    Polymer-ceramic composites with pyroelectric sensitivity are presented as promising candidates for sensing applications. Selection of the appropriate ceramic filler and the polymer matrix is one of the key parameters in the development of optimized materials for specific applications. In this work lead-titanate (PT) ceramic particulate is incorporated into a polymer matrix, polyethylene oxide (PEO) with a relatively high electrical conductivity to develop sensitive and at the same time flexible composites. PT particles are dispersed in PEO at varying volume fractions, and composite materials are cast in the form of films to measure their dielectric, piezoelectric and pyroelectric properties. From these data the piezoelectric voltage coefficients as well as pyroelctric figures of merit of the composite films have been determined. In order to determine the effect of electrical conductivity of the polymer matrix on the poling efficiency and the final properties, a poling study has been performed. Improving the electrical conductivity of the polymer phase enhances the poling process significantly. It is found that both the piezoelectric and the pyroelectric figures of merit increase with concentration of PT. PT-PEO composites show superior pyroelectric sensitivity compared to other composites with less conductive polymer matrices.

  20. Piezoelectric and pyroelectric properties of lead titanate-polyethylene oxide composites

    NASA Astrophysics Data System (ADS)

    Khanbareh, H.; van der Zwaag, S.; Groen, W. A.

    2014-11-01

    Polymer-ceramic composites with pyroelectric sensitivity are presented as promising candidates for infrared detection. Selection of the appropriate ceramic filler and the polymer matrix is one of the key parameters in the development of optimized materials for specific applications. In this work lead-titanate (PT) ceramic is incorporated into a flexible polymer matrix, polyethylene oxide (PEO) with relatively high electrical conductivity to develop sensitive and at the same time flexible composites. PT particles are dispersed in PEO at varying volume fractions, and composite materials cast in the form of films for the measurements. The dielectric, piezoelectric and pyroelectric properties are measured. From these data the piezoelectric voltage coefficients as well as pyroelctric figures of merit of the composite films have been determined and values were compared with that of PT-epoxy composites in order to determine the effect of electrical conductivity of the polymer matrix on the poling efficiency and the final properties. It is found that, in general, both the piezoelectric and the pyroelectric figures of merit increase with concentration of PT; however, it is at the expense of mechanical flexibility of the material. Moreover PT-PEO composites show superior pyroelectric sensitivity compared to PT-Epoxy composites. Improving the electrical conductivity of the polymer phase enhances the poling process significantly.