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. Piezoelectric properties of some lead-free ferroelectric ceramics

    Microsoft Academic Search

    Tadashi Takenaka

    1999-01-01

    The use of lead-free materials in piezoelectric ceramics has recently become a very important issue in environmental protection of the earth. Some lead-free piezoelectric materials, namely bismuth sodium titanate, (Bi1\\/2Na1\\/2)TiO3 (BNT) based solid solution ceramics, such as (1-a)BNT-aBaTiO3 [BNBT], (1-b)BNT-bNaNbO3 [BNTN] and a(Bi1\\/2Na1\\/2)TiO3-bKNbO3-c1\\/2(Bi2O3Sc2O3) [KTNS] (a+b+c=1) systems, were studied for their dielectric, ferroelectric and piezoelectric properties as candidates for a

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

    NASA Astrophysics Data System (ADS)

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

    2015-03-01

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

  4. Phase Transitions in Lead-free Piezoelectric Ceramics Monitored by the Resonance Method

    NASA Astrophysics Data System (ADS)

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

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

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

    SciTech Connect

    Khansur, Neamul H.; Daniels, John E. [School of Materials Science and Engineering, University of New South Wales, NSW 2052 (Australia); Groh, Claudia; Jo, Wook; Webber, Kyle G. [Institute of Materials Science, Technische Universitt Darmstadt, Alarich-Weiss-Strae 2, 64287 Darmstadt (Germany); Reinhard, Christina [Diamond Light Source, Beamline I12 JEEP, Didcot, Oxfordshire OX11 0DE (United Kingdom); Kimpton, Justin A. [The Australian Synchrotron, Clayton, Victoria 3168 (Australia)

    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.

  6. Electrical conductivity of the Bi-based lead-free piezoelectric ceramic BiFeO3

    Microsoft Academic Search

    Myong-Ho Kim

    2008-01-01

    Bi-based lead-free piezo-ceramics such as BiFeO3 (BFO) have been studied intensively in attempts to replace PZT-based ceramics. However, some of those ceramics have resistivity causing difficulties in poling thus yielding poor piezoelectric properties. To improve proper-ties, it is necessary to have better understanding on the conduction mechanism and defect chemistry of those systems. In this work, BNT as a base

  7. 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

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

    NASA Astrophysics Data System (ADS)

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

    2013-10-01

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

  9. Thermal Reliability of Alkaline Niobate-Based Lead-Free Piezoelectric Ceramics

    NASA Astrophysics Data System (ADS)

    Tanaka, Daisuke; Tsukada, Takeo; Furukawa, Masahito; Wada, Satoshi; Kuroiwa, Yoshihiro

    2009-09-01

    Alkaline niobate-based (K,Na,Li,Ba,Sr)(Nb,Ta,Zr)O3 (ANSZ) ceramics were prepared by conventional sintering process, and their piezoelectric properties were measured. The Curie temperature (TC) of the ANSZ ceramic was 278 C. The electromechanical coupling factor (kp) and the piezoelectric constant (d33) were 45.5% and 295 pC/N, respectively, and the dielectric permittivity (?33T/?0) was 1610 at room temperature. The thermal reliability was tested by 1000 cycles of thermal shock with temperatures ranging from -55 to 125 C. The change in d33 of ANSZ was compared with that of commercial Pb(Zr,Ti)O3 after 1000 cycles of thermal shock. The phase transition behavior of ANSZ was investigated by X-ray diffraction (XRD) and differential scanning calorimetry (DSC) simultaneous measurement. No appreciable endothermic peak accompanied by a polymorphic phase transition was observed on the DSC curve. The crystalline structure was investigated in detail by XRD measurement with high-energy synchrotron radiation. The coexistence of two ferroelectric phases in a wide temperature range (from -175 to 150 C) was observed.

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

    E-print Network

    Cao, Wenwu

    Dielectric and piezoelectric properties of sodium lithium niobate Na1-xLixNbO3 lead free # Springer Science + Business Media, LLC 2007 Abstract High density sodium lithium niobate lead free ce-to-paraelectric phase transition (tetragonal) takes place at about 354 C (Curie temperature). Lithium Niobate LiNbO3

  11. Piezoelectric and ferroelectric properties of Bi0.5(Na1-x-yKxAgy)0.5TiO3 lead-free piezoelectric ceramics

    NASA Astrophysics Data System (ADS)

    Liao, Yunwen; Xiao, Dingquan; Lin, Dunmin

    2008-01-01

    Lead-free piezoelectric ceramics Bi0.5(Na1-x-yKxAgy)0.5TiO3 [BNKAT(x/y)] have been synthesized by the mixed oxide method. The effects of the amount of K+ and Ag+ on the electrical properties were examined. X-ray diffraction patterns indicate that K+ and Ag+ ions partially substitute for the Na+ ions in Bi0.5Na0.5TiO3 and form a solid solution during sintering. At room temperature, the ceramics exhibit good performances with piezoelectric constant d33=189 pC/N, electromechanical coupling factor kp=35.0%, remanent polarization Pr=39.5 ?C/cm2, and coercive field Ec=3.3 kV/mm, respectively. The curves of the dielectric constant ?r and loss tangent tan ? versus temperature show that the transition temperature from ferroelectric to anti-ferroelectric phase decreases with increasing the K+ content for the compositions researched. The dependencies of kp and polarization versus electric (P E) hysteresis loops on temperature reveal that the depolarization temperature Td of BNKAT(0.15/0.015) ceramics, which have good piezoelectric properties (d33=134 pC/N, kp=32.5%) and strong ferroelectricity (Pr=39.5 ?C/cm2, Ec=4.1 kV/mm) at room temperature, is above 160 C.

  12. 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.

  13. Ferroelectric instabilities and enhanced piezoelectric response in Ce modified BaTiO3 lead-free ceramics

    NASA Astrophysics Data System (ADS)

    Brajesh, Kumar; Kalyani, Ajay Kumar; Ranjan, Rajeev

    2015-01-01

    The crystal structure, ferroelectric, and piezoelectric behaviors of the Ba(Ti1-xCex)O3 solid solution have been investigated at close composition intervals in the dilute concentration regime. Ce concentration as low as 2 mol. % induces tetragonal-orthorhombic instability and coexistence of the phases, leading to enhanced high-field strain and direct piezoelectric response. Detailed structural analysis revealed tetragonal + orthorhombic phase coexistence for x = 0.02, orthorhombic for 0.03 ? x ? 0.05, and orthorhombic + rhombohedral for 0.06 ? x ? 0.08. The results suggest that Ce-modified BaTiO3 is a potential lead-free piezoelectric material.

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

    NASA Astrophysics Data System (ADS)

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

    2013-05-01

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

  15. 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.

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

    SciTech Connect

    Tian, Ye [Key Laboratory for Macromolecular Science of Shaanxi Province, School of Materials Science and Engineering, Shaanxi Normal University, Xi'an 710062, Shaanxi (China); Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education and International Center for Dielectric Research, Xi'an Jiaotong University, Xi'an 710049, Shaanxi (China); Chao, Xiaolian, E-mail: chaoxl@snnu.edu.cn, E-mail: yangzp@snnu.edu.cn; Wei, Lingling; Liang, Pengfei; Yang, Zupei, E-mail: chaoxl@snnu.edu.cn, E-mail: yangzp@snnu.edu.cn [Key Laboratory for Macromolecular Science of Shaanxi Province, School of Materials Science and Engineering, Shaanxi Normal University, Xi'an 710062, Shaanxi (China); Jin, Li [Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education and International Center for Dielectric Research, Xi'an Jiaotong University, Xi'an 710049, Shaanxi (China)

    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.

  17. Polymorphic phase transition and piezoelectric properties of (Ba 1- xCa x)(Ti 0.9Zr 0.1)O 3 lead-free ceramics

    NASA Astrophysics Data System (ADS)

    Li, Wei; Xu, Zhijun; Chu, Ruiqing; Fu, Peng; Zang, Guozhong

    2010-11-01

    Lead-free (Ba 1- xCa x)(Ti 0.9Zr 0.1)O 3 ( x=0.12-0.18) (BCZT) ceramics were prepared successfully using a solid-state reaction technique. The polymorphic phase transitions (PPT) from rhombohedral to orthorhombic phase around room temperature were identified in the composition range 0.14< x<0.18. The samples at x=0.16, showing coexistence of rhombohedral and orthorhombic phase, exhibit enhanced piezoelectric and dielectric properties of d33=328 pC/N, kp=37.6% and ??=4800. With the increase of Ca content, the polymorphic phase transitions shift to lower temperature and cannot be observed above room temperature at x?0.18.

  18. Piezoelectric and ferroelectric properties of Cu-doped K0.5Na0.5NbO3 lead-free ceramics

    NASA Astrophysics Data System (ADS)

    Lin, Dunmin; Kwok, K. W.; Chan, H. L. W.

    2008-02-01

    CuO-doped K0.5Na0.5NbO3 (K0.5Na0.5NbO3 + x mol% CuO) lead-free ceramics have been prepared by an ordinary sintering technique. The results of x-ray diffraction patterns show that all the ceramics possess a pure pervoskite structure with orthorhombic symmetry. Based on the symmetry-conforming principle of point defects, defect dipoles are formed by the acceptor dopant ions Cu2+ and O2- vacancies along the polarization direction and remain in the original orientation, providing a restoring force to reverse the switched polarization, which results in double polarization-electric hysteresis loops for the ceramics with x >= 0.50 at 100 Hz. That is, the ferroelectric dipoles are back to their original orientation on the removal of electric field due to the strong restoring force generated by defect dipoles. As a result, the ceramics (x >= 0.5) become considerably 'hardened' and possess an extraordinarily high Qm (825-2523) and simultaneously the other piezoelectric properties remain reasonably good (kp = 39%, kt = 47% and d33 = 82 pC N-1).

  19. 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.

  20. 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.

  1. 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.

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

    PubMed

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

    2015-03-11

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

  3. Large Piezoelectric Constant and High Curie Temperature of Lead-Free Piezoelectric Ceramic Ternary System Based on Bismuth Sodium Titanate-Bismuth Potassium Titanate-Barium Titanate near the Morphotropic Phase Boundary

    Microsoft Academic Search

    Hajime Nagata; Masaki Yoshida; Yoichi Makiuchi; Tadashi Takenaka

    2003-01-01

    A lead-free piezoelectric ceramic ternary system based on bismuth sodium titanate, (Bi1\\/2Na1\\/2)TiO3 (BNT) - bismuth potassium titanate (Bi1\\/2K1\\/2)TiO3 (BKT) - barium titanate BaTiO3 (BT) near the morphotropic phase boundary (MPB) between the tetragonal and rhombohedral phases has been investigated. In the case of a(Bi1\\/2Na1\\/2)TiO3-bBaTiO3-c(Bi1\\/2K1\\/2)TiO3 [BNBK(100a\\/100b\\/100c)] solid solution ceramics, the highest piezoelectric constant d33=191 pC\\/N, Curie temperature, Tc=301C, electromechanical coupling factor,

  4. Correlation between the structure and the piezoelectric properties of lead-free (K,Na,Li)(Nb,Ta,Sb)O3 ceramics studied by XRD and Raman spectroscopy.

    PubMed

    Rubio-Marcos, Fernando; Marchet, Pascal; Romero, Juan Jos; Fernndez, Jose F

    2011-09-01

    This article reviews on the use of Raman spectroscopy for the study of (K,Na,Li)(Nb,Ta,Sb)O(3) lead-free piezoceramics. Currently, this material appears to be one of the most interesting and promising alternatives to the well-known PZT piezoelectric materials. In this work, we prepare piezoceramics with different stoichiometries and study their structural, ferroelectric, and piezoelectric properties. By using both Raman spectroscopy and X-ray diffraction, we establish a direct correlation between the structure and the properties. The results demonstrate that the wavenumber of the A(1g) vibration is proportional to the tetragonality, the remnant polarization, and the piezoelectric coefficients of these materials. Thus, Raman spectroscopy appears as a very useful technique for a fast evaluation of the crystalline structure and the ferroelectric/ piezoelectric properties. PMID:21937314

  5. 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.

  6. Lead-Free Piezoelectric Ceramics of (Bi1\\/2Na1\\/2)TiO3 KNbO3 1\\/2(Bi2O3Sc2O3) System

    Microsoft Academic Search

    Hajime Nagata; Tadashi Takenaka

    1998-01-01

    Bismuth sodium titanate, (Bi1\\/2Na1\\/2)TiO3 (BNT)-based solid solution, a(Bi1\\/2Na1\\/2)TiO3 bKNbO3 c1\\/2(Bi2O3Sc2O3) (a+b+c=1), [KTNS(100a\\/100b\\/100c)], was studied for its dielectric, ferroelectric and piezoelectric properties, as a new group of lead-free piezoelectric ceramics. Electrical measurements such as dielectric and piezoelectric properties show that the KTNS(100a\\/100b\\/100c) ceramics near the BNT side have a relatively high electromechanical coupling factor, k33 (=0.47). On particular, the amount of

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

    NASA Astrophysics Data System (ADS)

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

    2014-07-01

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

  8. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-02-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-06-01

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

  11. Sintering Behaviour and Piezoelectric Properties of CuO-Added Lead-Free Bi(Na,K)TiO3 Ceramics

    Microsoft Academic Search

    Hyoung-Su Han; Nam-Binh Do; Ky-Nam Pham; Hyun-Deok Jang; Vu Diem Ngoc Tran; Weon-Pil Tai; Jae-Shin Lee

    2011-01-01

    Effect of excess CuO on the sintering behaviour and piezoelectric properties of Bi0.5(Na82K0.18)0.5TiO3 ceramics was investigated. The addition of small amount of excess CuO as low as 0.01 mol was quite effective to lower the sintering temperature (Ts) of BNKT ceramics down to 975C which is 200C lower than the Ts of pure BNKT (1175C) without significant degradation of their

  12. 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.

  13. PHASE TRANSITION, DIELECTRIC AND PIEZOELECTRIC PROPERTIES OF NaNbO3-Ba0.85Ca0.15(Ti0.9Zr0.1)O3 LEAD-FREE CERAMICS

    NASA Astrophysics Data System (ADS)

    Lei, Yuqing; Wu, Hong; Lin, Dunmin; Zheng, Qiaoji; Wu, Xiaochun; Fan, Ximing

    2012-09-01

    A new lead-free solid solution of (1-x)NaNbO3-xBa0.85Ca0.15(Ti0.9Zr0.1)O3 was prepared by a traditional sintering method and its phase transition, dielectric and piezoelectric properties were studied. Ba0.85Ca0.15(Ti0.9Zr0.1)O3 diffuses into NaNbO3 lattices to form a new solid solution with perovskite structure. The addition of Ba0.85Ca0.15(Ti0.9Zr0.1)O3(x?0.025) transforms NaNbO3 from antiferroelectric to ferroelectric. The diffusive ferroelectric-paraelectric phase transition is induced in the ceramics with high concentration of Ba0.85Ca0.15(Ti0.9Zr0.1)O3. The ceramics with x = 0.05-0.125 possess large Pr values of 18.6-25.5 ?C/cm2. A morphotropic phase boundary between tetragonal and orthorhombic phases is formed at 0.05 < x < 0.15, leading to a significant enhancement of piezoelectric properties. The ceramic with x = 0.125 situated near the morphotropic phase boundary exhibits the optimum piezoelectric properties: d33 = 151 pC/N and kp = 31.6%.

  14. Investigation of a new lead-free Bi0.5(Na0.40K0.10)TiO3-(Ba0.7Sr0.3)TiO3 piezoelectric ceramic

    PubMed Central

    2012-01-01

    Lead-free piezoelectric compositions of the (1-x)Bi0.5(Na0.40K0.10)TiO3-x(Ba0.7Sr0.3)TiO3 system (when x = 0, 0.05, 0.10, 0.15, and 0.20) were fabricated using a solid-state mixed oxide method and sintered between 1,050C and 1,175C for 2 h. The effect of (Ba0.7Sr0.3)TiO3 [BST] content on phase, microstructure, and electrical properties was investigated. The optimum sintering temperature was 1,125C at which all compositions had densities of at least 98% of their theoretical values. X-ray diffraction patterns that showed tetragonality were increased with the increasing BST. Scanning electron micrographs showed a slight reduction of grain size when BST was added. The addition of BST was also found to improve the dielectric and piezoelectric properties of the BNKT ceramic. A large room-temperature dielectric constant, ?r (1,609), and piezoelectric coefficient, d33 (214 pC/N), were obtained at an optimal composition of x = 0.10. PMID:22221833

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

    PubMed Central

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

    2013-01-01

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

  16. 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.

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

    NASA Astrophysics Data System (ADS)

    Mahesh, P.; Pamu, D.

    2015-02-01

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

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

    PubMed

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

    2014-03-01

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

  19. 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 [Department of Materials Science, Sichuan University, Chengdu 610064 (China); Wang Yuanyu [Department of Materials Science, Sichuan University, Chengdu 610064 (China) and College of Materials Science and Metallurgy Engineering, Guizhou University, Guizhou 550003 (China)

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2007-12-01

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

  1. Large field-induced strains in a lead-free piezoelectric material

    Microsoft Academic Search

    J. X. Zhang; B. Xiang; Q. He; J. Seidel; R. J. Zeches; P. Yu; S. Y. Yang; C. H. Wang; Y.-H. Chu; L. W. Martin; A. M. Minor; R. Ramesh

    2011-01-01

    Piezoelectric materials exhibit a mechanical response to electrical inputs, as well as an electrical response to mechanical inputs, which makes them useful in sensors and actuators. Lead-based piezoelectrics demonstrate a large mechanical response, but they also pose a health risk. The ferroelectric BiFeO3 is an attractive alternative because it is lead-free, and because strain can stabilize BiFeO3 phases with a

  2. 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

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

    NASA Astrophysics Data System (ADS)

    Jeon, Yu Hong

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

  4. Lead-free package interconnections for ceramic grid arrays

    Microsoft Academic Search

    Mario Interrante; Jeffrey Coffin; Marie Cole; Isabel De Sousa; Mukta Farooq; Lewis Goldmann; Charles Goldsmith; J. Jozwiak; T. Lopez; G. Martin; Van Thanh Troung; D. Welsh

    2003-01-01

    As the electronics industry moves to eliminate lead from its components and solder assembly processes, new challenges arise in developing reliable interconnect processes. For the surface mount attachment of multilayer ceramic packages, this challenge becomes increasingly difficult in second-level assembly because of the large coefficient of thermal expansion (CTE) mismatch between the ceramic chip carrier and epoxy glass printed circuit

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

    PubMed Central

    2014-01-01

    In a flexible nanocomposite-based nanogenerator, in which piezoelectric nanostructures are mixed with polymers, important parameters to increase the output power include using long nanowires with high piezoelectricity and decreasing the dielectric constant of the nanocomposite. Here, we report on piezoelectric power generation from a lead-free LiNbO3 nanowire-based nanocomposite. Through ion exchange of ultra-long Na2Nb2O6-H2O nanowires, we synthesized long (approximately 50?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

  6. Large field-induced strains in a lead-free piezoelectric material.

    PubMed

    Zhang, J X; Xiang, B; He, Q; Seidel, J; Zeches, R J; Yu, P; Yang, S Y; Wang, C H; Chu, Y-H; Martin, L W; Minor, A M; Ramesh, R

    2011-02-01

    Piezoelectric materials exhibit a mechanical response to electrical inputs, as well as an electrical response to mechanical inputs, which makes them useful in sensors and actuators. Lead-based piezoelectrics demonstrate a large mechanical response, but they also pose a health risk. The ferroelectric BiFeO(3) is an attractive alternative because it is lead-free, and because strain can stabilize BiFeO(3) phases with a structure that resembles a morphotropic phase boundary. Here we report a reversible electric-field-induced strain of over 5% in BiFeO(3) films, together with a characterization of the origins of this effect. In situ transmission electron microscopy coupled with nanoscale electrical and mechanical probing shows that large strains result from moving the boundaries between tetragonal- and rhombohedral-like phases, which changes the phase stability of the mixture. These results demonstrate the potential of BiFeO(3) as a substitute for lead-based materials in future piezoelectric applications. PMID:21240285

  7. 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.

  8. 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.

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

    SciTech Connect

    Li, Jun, E-mail: lijuna@hit.edu.cn [Department of Physics, Harbin Institute of Technology, Harbin 150001 (China); Li, Yang [Department of chemistry, Harbin Institute of Technology, Harbin 150001 (China); Zhou, Zhongxiang [Department of Physics, Harbin Institute of Technology, Harbin 150001 (China); Guo, Ruyan; Bhalla, Amar S. [Multifunctional Electronic Materials and Device Research Lab, Department of Electrical and Computer Engineering, The University of Texas at San Antonio, San Antonio 78249 (United States)

    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.

  10. 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 0.88NaNbO30.12LiTaO3. 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 ringdot 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.

  11. Growth and properties of Li, Ta modified (K,Na)NbO3 lead-free piezoelectric single crystals

    PubMed Central

    Huo, Xiaoqing; Zheng, Limei; Zhang, Shujun; Zhang, Rui; Liu, Gang; Wang, Rui; Yang, Bin; Cao, Wenwu; Shrout, Thomas R.

    2014-01-01

    Li, Ta modified (K,Na)NbO3 single crystals with the size of 18 mm 18 mm 10 mm were successfully grown by top-seeded solution growth method, with orthorhombictetragonal phase transition temperature ~79 C and Curie temperature ~276 C. The electromechanical coupling factors k33 and kt were found to be ~88% and ~65%, respectively. The piezoelectric coefficient d33 for the [001]c poled crystals reached 255 pC/N. In addition, the electromechanical coupling factor exhibited high stability over the temperature range of ?50 C to 70 C, making these lead free crystals good candidates for electromechanical applications. PMID:25404953

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

    NASA Astrophysics Data System (ADS)

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

    2014-06-01

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

  13. 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

  14. 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 [State Key Laboratory of Solidification Processing, School of Materials Science and Engineering, Northwestern Polytechnical University, Xian 710072 (China) [State Key Laboratory of Solidification Processing, School of Materials Science and Engineering, Northwestern Polytechnical University, Xian 710072 (China); Department of Mechanical Engineering, The Hong Kong Polytechnic University, Hung Hum, Kowloon (Hong Kong); Fan, Huiqing, E-mail: hqfan3@163.com [State Key Laboratory of Solidification Processing, School of Materials Science and Engineering, Northwestern Polytechnical University, Xian 710072 (China)] [State Key Laboratory of Solidification Processing, School of Materials Science and Engineering, Northwestern Polytechnical University, Xian 710072 (China); Ke, Shanming [Department of Mechanical Engineering, The Hong Kong Polytechnic University, Hung Hum, Kowloon (Hong Kong) [Department of Mechanical Engineering, The Hong Kong Polytechnic University, Hung Hum, Kowloon (Hong Kong); Department of Applied Physics and Materials Research Center, The Hong Kong Polytechnic University, Hung Hum, Kowloon (Hong Kong); Zhou, Limin [Department of Mechanical Engineering, The Hong Kong Polytechnic University, Hung Hum, Kowloon (Hong Kong)] [Department of Mechanical Engineering, The Hong Kong Polytechnic University, Hung Hum, Kowloon (Hong Kong); Mai, Yiu-Wing [Department of Mechanical Engineering, The Hong Kong Polytechnic University, Hung Hum, Kowloon (Hong Kong) [Department of Mechanical Engineering, The Hong Kong Polytechnic University, Hung Hum, Kowloon (Hong Kong); Centre for Advanced Materials Technology, School of Aerospace, Mechanical and Mechatronics Engineering J07, The University of Sydney, Sydney, NSW 2006 (Australia); Huang, Haitao, E-mail: aphhuang@polyu.edu.hk [Department of Applied Physics and Materials Research Center, The Hong Kong Polytechnic University, Hung Hum, Kowloon (Hong Kong)] [Department of Applied Physics and Materials Research Center, The Hong Kong Polytechnic University, Hung Hum, Kowloon (Hong Kong)

    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%).

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

    PubMed

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

    2014-01-01

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

  16. Growth and characterization of undoped and Mn doped lead-free piezoelectric NBTKBT single crystals

    SciTech Connect

    Babu, G. Anandha, E-mail: anandcgc@gmail.com [Centre for Crystal Growth, SSN College of Engineering, Kalavakkam 603 110 (India); Subramaniyan, Raja R. [Centre for Crystal Growth, SSN College of Engineering, Kalavakkam 603 110 (India); Bhaumik, Indranil [Laser Materials Development and Devices Division, Raja Ramanna Centre for Advanced Technology, Indore 452 013 (India); Ganesamoorthy, S. [X-ray Scattering and Crystal Growth Section, Condensed Matter Physics Division, Materials Science Group, IGCAR, Kalpakkam 603102 (India); Ramasamy, P. [Centre for Crystal Growth, SSN College of Engineering, Kalavakkam 603 110 (India); Gupta, P.K. [Laser Materials Development and Devices Division, Raja Ramanna Centre for Advanced Technology, Indore 452 013 (India)

    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.

  17. 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.

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

    SciTech Connect

    Jiang, Xijie; Wang, Baoyin [Department of Microelectronic Science and Engineering, Ningbo University, 315211 Ningbo (China); Luo, Laihui, E-mail: llhsic@126.com [Department of Microelectronic Science and Engineering, Ningbo University, 315211 Ningbo (China); Li, Weiping; Zhou, Jun [Department of Microelectronic Science and Engineering, Ningbo University, 315211 Ningbo (China); Chen, Hongbing [State Key Base of Novel Functional Materials and its Preparation Science, Institute of Materials Science and Engineering, Ningbo University, Ningbo 315211 (China)

    2014-05-01

    In this investigation, a simple compound (1?x)(Bi{sub 0.5}Na{sub 0.5})TiO{sub 3}xKNbO{sub 3} (BNTxKN, x=00.08) lead-free ceramics were synthesized successfully by conventional solid state reaction method. The piezoelectric, dielectric and ferroelectric characteristics of the ceramics were investigated and discussed. The results shows that moderate KN addition can enhance the piezoelectric response without an obvious decline of ferroelectric properties. The largest piezoelectric response is obtained in BNT0.05KN, whereas largest electric-field-induced strain is obtained in BNT0.06KN. An effective d{sub 33}{sup eff} of ?400 pC/N calculated from electric-field-induced strain is obtained in BNT0.06KN. The present investigation demonstrates that addition KN effectively reduces the depolarization temperature of the BNTxKN ceramics. The electrical properties of the ceramics are tightly related to their depolarization temperature. - Graphical abstract: Unipolar electric-field-induced strain for the BNTxKN ceramics. A maximum strain of 0.28% is achieved with a low field in BNT0.06KN. - Highlights: Moderate KNbO{sub 3} addition enhances the piezoelectric properties of the ceramics. A maximum strain of 0.28% is achieved with a low field. A large piezoelectric response is achieved in 0.95(Bi{sub 0.5}Na{sub 0.5})TiO{sub 3}0.05KNbO{sub 3}. The electrical properties are tightly related to the depolarization temperature T{sub d}.

  19. Ferroelectric polarization and domain walls in orthorhombic (K1-xNax)NbO3 lead-free ferroelectric ceramics

    NASA Astrophysics Data System (ADS)

    Lu, Ning; Yu, Rong; Cheng, Zhiying; Dai, Yejing; Zhang, Xiaowen; Zhu, Jing

    2010-05-01

    Combining aberration-corrected high-resolution transmission electron microscopy with first-principles calculations, we have investigated the ferroelectric polarization and the atomic structures of 60/120 domain walls in orthorhombic (K0.46Na0.54)NbO3 lead-free ferroelectric ceramics. The projections of cation-oxygen dipoles across the 60/120 domain walls were determined using the recently developed negative spherical-aberration imaging technique. The measured ferroelectric distortion matched well with that obtained from first-principles calculations. The width across the wall was measured to be 1.1 nm.

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

    SciTech Connect

    Hrovat, Marko, E-mail: marko.hrovat@ijs.si [Joef Stefan Institute, Jamova Cesta 39, SI-1000 Ljubljana (Slovenia) [Joef Stefan Institute, Jamova Cesta 39, SI-1000 Ljubljana (Slovenia); CoE NAMASTE, Jamova Cesta 39, SI-1000 Ljubljana (Slovenia); Kielbasinski, Konrad [Institute of Electronic Materials Technology, Wlczy?ska 133, 01-919 Warsaw (Poland) [Institute of Electronic Materials Technology, Wlczy?ska 133, 01-919 Warsaw (Poland); Institute of Microelectronics and Optoelectronics, Warsaw University of Technology, Koszykowa 75, 00-662 Warsaw (Poland); Makarovi?, Kostja [Joef Stefan Institute, Jamova Cesta 39, SI-1000 Ljubljana (Slovenia) [Joef Stefan Institute, Jamova Cesta 39, SI-1000 Ljubljana (Slovenia); CoE NAMASTE, Jamova Cesta 39, SI-1000 Ljubljana (Slovenia); Belavi?, Darko [HIPOT-RR d.o.o., entpeter 18, SI-8222 Oto?ec (Slovenia) [HIPOT-RR d.o.o., entpeter 18, SI-8222 Oto?ec (Slovenia); CoE NAMASTE, Jamova Cesta 39, SI-1000 Ljubljana (Slovenia); Jakubowska, Malgorzata [Institute of Electronic Materials Technology, Wlczy?ska 133, 01-919 Warsaw (Poland) [Institute of Electronic Materials Technology, Wlczy?ska 133, 01-919 Warsaw (Poland); Faculty of Mechatronics, Warsaw University of Technology, ?w. Andrzeja Boboli 8, 02-525 Warsaw (Poland)

    2012-12-15

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

  2. Piezoelectric ceramics and ceramic composites for intelligent mechanical behaviors

    SciTech Connect

    Wang, Hongyu; Singh, R.N. [Univ. of Cincinnati, OH (United States)

    1994-12-31

    Crack propagation in piezoelectric PZT ceramics under applied static electric fields has been studied using the Vickers indentation technique in an effort to develop the intelligent mechanical responses of ferroelectric ceramics and ceramic composites. It was observed that crack lengths decreased under a positive applied field (the polarity of the applied electric field was the same as that for poling) and increased under a negative applied field. Such an effect became more profound with increasing field strength. These observations were in contrary to tile expectation based on the piezoelectric characteristics of PZT ceramics. The direction of surface polishing had little effect on the crack extension behavior. More work is being done to further investigate the mechanisms for the observed behavior, including the possibility of a 180{degrees} domain switching in the surface layer because of the surface polishing.

  3. Piezoelectric ceramics for high reliability ring laser gyros

    Microsoft Academic Search

    W. B. Harrison; R. G. Langton

    1988-01-01

    Piezoelectric ceramic micropositioning transducers and dithering motors have been used extensively in ring laser gyros (RLG) supplied to DOD and Commercial Avionics customers. The three applications for these elements are path length control (PLC) transducers, dither motor piezoelectric bender elements and dither motor sensors. This paper will review the operation of the RLG and the unique piezoelectric ceramics used, and

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

    SciTech Connect

    Chauhan, Aditya; Patel, Satyanarayan; Vaish, Rahul, E-mail: rahul@iitmandi.ac.in [School of Engineering, Indian Institute of Technology Mandi, 175 001 (India)

    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.

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

    NASA Astrophysics Data System (ADS)

    Chauhan, Aditya; Patel, Satyanarayan; Vaish, Rahul

    2014-08-01

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

  6. Hydrostatic piezoelectric effect in lead titanate ceramics

    SciTech Connect

    Lopatin, S.S.; Lupeiko, T.G.; Zvyagintsev, B.I. [Rostov State Univ. (Russian Federation)] [and others

    1994-10-01

    The hydrostatic piezoelectric characteristics of Pb{sub 0.955-x}Sm{sub 2x/3}Bi{sub 0.03}Ti{sub 0.98}Mn{sub 0.02}O{sub 3} ceramics were studied. Within the range of at least 25 to 70 degrees C and at high hydrostaic and uniaxial pressures of 0.1-60 MPa, a high stability of the no-load piezoelectric voltage coefficient for the material with x=0.09-0.15 was found.

  7. Product property between thermal expansion and piezoelectricity in piezoelectric ceramic-polymer composites

    Microsoft Academic Search

    Xiaoping Zou; Liangying Zhang; Xi Yao; Likun Wang; Fuxue Zhang

    1996-01-01

    The product property between thermal expansion and piezoelectricity in composites prepared from piezoelectric ceramics and polymers is presented. A theoretical analysis on the product property is discussed based on series and parallel models of the composites. From the theoretical analysis, the necessary condition for the highest product effect of diphasic composites is discussed. Composites with piezoelectric ceramic PZT particles, TGS

  8. 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.

  9. 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

  10. 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

  11. Electrocaloric Effect of Lead-Free (Ba,Ca)(Zr,Ti)O3 Ferroelectric Ceramic

    NASA Astrophysics Data System (ADS)

    Kim, You Seok; Yoo, Juhyun

    2015-03-01

    In this study, (Ba,Ca)(Zr,Ti)O3 ferroelectric ceramic was fabricated by a conventional solid-state reaction process. The electrocaloric effect was investigated using P-E hysteresis loop characteristics in a wide temperature range from room temperature to 135C. The results showed that the temperature change ?T could be calculated as a function of temperature using Maxwell's relation, reaching a maximum value of ~0.096C at 110C under an applied electric field of 15.3 kV/cm.

  12. 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.

  13. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-03-01

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

  15. Instabilities in the piezoelectric properties of ferroelectric ceramics

    Microsoft Academic Search

    D Damjanovic; M Demartin; H. S Shulman; M Testorf; N Setter

    1996-01-01

    The large piezoelectric effect of ferroelectric ceramics is utilized in many devices for sensing and actuating purposes. In this paper, the longitudinal direct piezoelectric effect in ceramics based on lead zirconate titanate, lead titanate, barium titanate and bismuth titanate is investigated as a function of the amplitude and frequency of the external pressure, the crystal structure and microstructure of the

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

    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 (K0.5Bi0.5TiO3-BaTiO3-Na0.5Bi0.5TiO3 (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 (,1606C). 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-1806 domain switching, in comparison to the randomly axed ones. These results indicate the effective solution to the lead-free piezoelectricmorematerials.less

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

    SciTech Connect

    Rani, Rashmi; Sharma, Seema [Ferroelectric Research Laboratory, Department of Physics, A.N. College, Patna 800 013 (India)] [Ferroelectric Research Laboratory, Department of Physics, A.N. College, Patna 800 013 (India); Rai, Radheshyam, E-mail: radheshyamrai@ua.pt [Department of Ceramics and Glass Engineering and CICECO, University of Aveiro, 3810-193 Aveiro (Portugal)] [Department of Ceramics and Glass Engineering and CICECO, University of Aveiro, 3810-193 Aveiro (Portugal); Kholkin, Andrei L. [Department of Ceramics and Glass Engineering and CICECO, University of Aveiro, 3810-193 Aveiro (Portugal)] [Department of Ceramics and Glass Engineering and CICECO, University of Aveiro, 3810-193 Aveiro (Portugal)

    2012-02-15

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

  18. 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

  19. Electromechanical properties of Nd-doped Bi4Ti3O12 films: A candidate for lead-free thin-film piezoelectrics

    Microsoft Academic Search

    Hiroshi Maiwa; Naoya Iizawa; Daichi Togawa; Takashi Hayashi; Wataru Sakamoto; Mio Yamada; Shin-Ichi Hirano

    2003-01-01

    Neodymium-doped Bi4Ti3O12 (BNT) films are evaluated for use as lead-free thin-film piezoelectrics in microelectromechanical systems. Bi4Ti3O12, Bi3.25La0.75Ti3O12, and Bi3.25Nd0.75Ti3O12 films were fabricated by chemical solution deposition on Pt\\/TiOx\\/SiO2\\/Si substrates. Nd substitution promoted random orientation with low (00l) diffraction peaks. The 1-mum-thick Bi3.25Nd0.75Ti3O12 film annealed at 750 C exhibited a remanent polarization of 26 muC\\/cm2. Typical butterfly field-induced strain loops were

  20. 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.

  1. Lead-free piezoceramics

    Microsoft Academic Search

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

    2004-01-01

    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

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

  3. Piezoelectric properties of 0.5(Ba0.7Ca0.3TiO3) - 0.5[Ba(Zr0.2Ti0.8)O3] ferroelectric lead-free laser deposited thin films

    NASA Astrophysics Data System (ADS)

    Piorra, A.; Petraru, A.; Kohlstedt, H.; Wuttig, M.; Quandt, E.

    2011-05-01

    Ferroelectric lead-free thin films of 0.5(Ba0.7Ca0.3TiO3) - 0.5[Ba(Zr0.2Ti0.8)O3] (BCZT) were successfully deposited by pulsed laser deposition on Pt/TiO2/SiO2/Si substrates using a ceramic BCZT target prepared by conventional solid state reaction. The in (111) direction orientated 600 nm thick films shows a clamped piezoelectric response of approximately d33,f = 80 pm/V and a dielectric coefficient of about ?r = 1010; these are close to values obtained for lead zirconate titanate (PZT) films.

  4. 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. [Department of Physics, Faculty of Science, Chiang Mai University, Chiang Mai 50202 (Thailand); Intatha, U. [School of Science, Mae Fha Luang University, Chiang Rai, 57100 (Thailand); Sirisoonthorn, S. [National Metal and Materials Technology Center, Klong Luang, Pathumthani 12120 (Thailand)

    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.

  5. Piezoelectric Properties of BaTiO3-(Bi1\\/2K1\\/2)TiO3 Ferroelectric Ceramics

    Microsoft Academic Search

    Yuji Hiruma; Rintaro Aoyagi; Hajime Nagata; Tadashi Takenaka

    2004-01-01

    The dielectric, ferroelectric and piezoelectric properties of barium titanate (BaTiO3)-based solid solution, (1-x)BaTiO3-x(Bi1\\/2K1\\/2)TiO3 (0<= x<= 1) (BT-BKT100x), a candidate lead-free piezoelectric ceramic, were studied using a starting material of fine BaTiO3 powder. The Curie temperature, Tc, of the BT-BKT ceramics shifted to higher temperatures than those of BT with increasing the amount (x) of (Bi1\\/2K1\\/2)TiO3 and Tc was higher than

  6. Piezoelectric Properties of Pure and Mn-doped Potassium Niobate Ferroelectric Ceramics

    Microsoft Academic Search

    Kenji Matsumoto; Yuji Hiruma; Hajime Nagata; Tadashi Takenaka

    2006-01-01

    Potassium niobate, KNbO3 (KN), ceramics doped with manganese (Mn) were prepared by the conventional ceramic fabrication process to characterize their electrical properties. The difficulty in obtaining dense ceramics by conventional methods limits our knowledge of the piezoelectricity of this ceramic. In this paper, an optimized process for obtaining dense (over 95%) and nondeliquescent KN ceramics is described. Dielectric and piezoelectric

  7. Switching characteristics of (Bi 1/2Na 1/2)TiO 3-BaTiO 3-(Bi 1/2K 1/2)TiO 3 lead-free ferroelectric ceramics

    NASA Astrophysics Data System (ADS)

    Shieh, J.; Wu, K. C.; Chen, C. S.

    2007-04-01

    The polarization switching characteristics of lead-free a(Bi 1/2Na 1/2)TiO 3-bBaTiO 3-c(Bi 1/2K 1/2)TiO 3 (abbreviated as BNBK 100a/100b/100c) ferroelectric ceramics are investigated. This is achieved through examining their polarization and strain hystereses inside and outside the morphotropic phase boundary (MPB). The total induced electrostrain (? 33,total) and apparent piezoelectric charge coefficient (d 33) first increase dramatically and then decrease gradually as the BNBK composition moves from the tetragonal phase to the MPB and then to the rhombohedral phase. The measured polarization hystereses indicate that the BNBK compositions situated near the rhombohedral side of the MPB typically possess higher coercive field (E c) and remanent polarization (P r), while the compositions situated near the tetragonal side of the MPB possess higher apparent permittivity. Adverse effects on the ferroelectric properties are observed when BNBK is doped with donor dopants such as La and Nb. On the contrary, intricate hysteresis behaviors are observed when acceptor dopant Mn is introduced into BNBK. Under an alternating electric field of +/-5.0 MVm -1, BNBK 85.4/2.6/12, a composition well within the MPB, exhibits an ? 33,total of ~0.14%, an apparent d 33 of 295 pCN -1, an E c of 2.5 MVm -1 and a Pr of 22.5 ?Ccm -2. These notable ferroelectric property values suggest a candidate material for lead-free actuator applications. The present study provides a systematic set of hysteresis measurements which can be used to characterize the switching behaviors of BNBK-based lead-free ferroelectrics.

  8. 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.

  9. High-Power Piezoelectric Characteristics of Nontextured Bismuth Layer-Structured Ferroelectric Ceramics

    NASA Astrophysics Data System (ADS)

    Nagata, Hajime; Seki, Masahiro; Noumura, Yoji; Hiruma, Yuji; Takenaka, Tadashi

    2011-09-01

    High-power piezoelectric characteristics under continuous driving were studied on some bismuth layer-structured ferroelectric ceramics, i.e., Sr0.25Bi2.75Ti0.75Ta1.25O9 (SBTT, m = 2), Bi4Ti2.98V0.02O12 (BITV, m = 3), Bi4Ti3O12-SrBi4Ti4O15 + MnCO3 0.2 wt % (BIT-SBTi, m = 3, 4), and (Sr0.7Ca0.3)2Bi4Ti5O18 + MnCO3 0.2 wt % (SCBT, m = 5). The vibration velocities, v0-p, of SBTT, BIT-SBTi, and SCBT ceramics were above 2.0 m/s at 5 V/mm. Also, we observed that the resonance frequency changes and temperatures on the sample surfaces for SBTT, BIT-SBTi, and SCBT ceramics were less than 1.0% and 50 C at a v0-p of 2.0 m/s, respectively. The high-power characteristics of the ceramics were superior to those of BITV and hard Pb(Zr,Ti)O3 (abbreviated as PZT) at a vibration velocity v0-p > 0.6 m/s. Therefore, SBTT, BIT-SBTi and SCBT ceramics are promising candidates for lead-free high-power applications requiring high vibration velocity and frequency stability.

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

    NASA Astrophysics Data System (ADS)

    Koruza, J.; Roi?, B.; Cordoyiannis, G.; Mali?, B.; Kutnjak, Z.

    2015-05-01

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

  11. Plasma crystallization of polymer-ferroelectric/piezoelectric ceramic composites and their piezoelectric properties

    NASA Astrophysics Data System (ADS)

    Kurbanov, M. A.; Sultanakhmedova, I. S.; Kerimov, . A.; Aliev, Kh. S.; Aliev, G. G.; Ge?darov, G. M.

    2009-06-01

    The crystallization of polymer-ferroelectric/piezoelectric ceramic composites under the action of an electric discharge plasma and temperature is investigated. It is shown that this process results in strong oxidation of polymer chains. The oxidation of polymer chains is accompanied by an enhancement of interfacial interactions and an increase in the concentration of charge localization centers or the number of local levels in the quasi-band gap of the polymer phase, which upon polarization leads to an increase in interfacial charges. These charges and oxidation of polymer chains favor the effective polarization of piezoelectric phase domains and, hence, an increase in the piezoelectric parameters of the composite.

  12. 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).

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

    NASA Astrophysics Data System (ADS)

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

    2013-05-01

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

  14. Plasma crystallization of polymer-ferroelectric\\/piezoelectric ceramic composites and their piezoelectric properties

    Microsoft Academic Search

    M. A. Kurbanov; I. S. Sultanakhmedova; . A. Kerimov; Kh. S. Aliev; G. G. Aliev; G. M. Geidarov

    2009-01-01

    The crystallization of ``polymer-ferroelectric\\/piezoelectric ceramic'' composites under the action of an electric discharge plasma and temperature is investigated. It is shown that this process results in strong oxidation of polymer chains. The oxidation of polymer chains is accompanied by an enhancement of interfacial interactions and an increase in the concentration of charge localization centers or the number of local levels

  15. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2007-04-01

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

  17. COLD SPRAY ELECTRODING OF PIEZOELECTRIC CERAMIC

    Microsoft Academic Search

    P. C. King; S. H. Zahiri; M. Jahedi; J. Friend

    Lead zirconate titanate (PZT) is a piezoelectric material that is used in a wide range of applications from small actuators for the precise movement of lenses and mirrors to ultrasonic generators for the industrial mixing and emulsification of liquids. Conventional bonding of PZT involves the use of adhesives which dampen the movement of the element. This paper is a summary

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

    NASA Astrophysics Data System (ADS)

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

    2014-07-01

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

  19. Plasma crystallization of polymer-ferroelectric\\/piezoelectric ceramic composites and their piezoelectric properties

    Microsoft Academic Search

    M. A. Kurbanov; I. S. Sultanakhmedova; . A. Kerimov; Kh. S. Aliev; G. G. Aliev; G. M. Ge?darov

    2009-01-01

    The crystallization of polymer-ferroelectric\\/piezoelectric ceramic composites under the action of an electric discharge\\u000a plasma and temperature is investigated. It is shown that this process results in strong oxidation of polymer chains. The oxidation\\u000a of polymer chains is accompanied by an enhancement of interfacial interactions and an increase in the concentration of charge\\u000a localization centers or the number of local levels

  20. Realization of high-energy density polycrystalline piezoelectric ceramics

    SciTech Connect

    Islam, Rashed Adnan; Priya, Shashank [Material Science and Engineering, University of Texas at Arlington, Arlington, Texas 76019 (United States)

    2006-01-16

    This letter reports a high energy density piezoelectric material in the system given as: Pb[(Zr{sub 0.52}Ti{sub 0.48})O{sub 3}]{sub 1-x}[(Zn{sub 1/3}Nb{sub 2/3})O{sub 3}]{sub x}+yMnCO{sub 3}, where x=0.1 and y varies from 0.5 to 0.9 wt %. A piezoelectric material with high energy density is characterized by a high product of piezoelectric voltage constant (g) and piezoelectric strain constant (d). The condition for obtaining large magnitude of g constant was derived to be as |d|={epsilon}{sup n}, where {epsilon} is the permittivity of the material and n is constant having lower bound of 0.5. It was found that for all practical polycrystalline piezoelectric ceramic materials the magnitude of n lies in the range of 1.1-1.30 and as the magnitude of n decreases towards unity a giant enhancement in the magnitude of g was obtained. A two step sintering process was developed to optimize a polycrystalline ceramic composition with low magnitude of n. For the optimized composition the value of g{sub 33} and d{sub 33} was found to be 55.56x10{sup -3} m{sup 2}/C and 291x10{sup -12} C/N, respectively, yielding the magnitude product d{sub 33}{center_dot}g{sub 33} as {approx}16168x10{sup -15} m{sup 2}/N which is significantly higher than the reported values in literature. The magnitude of n for this composition was calculated to be 1.151. This material is extremely promising for immediate applications in the sensing and energy harvesting.

  1. 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, E-mail: jingfeng@mail.tsinghua.edu.cn [State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, 100084 Beijing (China)] [State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, 100084 Beijing (China)

    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.

  2. Novel piezoelectric ceramics: Development of high temperature, high performance piezoelectrics on the basis of structure

    NASA Astrophysics Data System (ADS)

    Eitel, Richard E.

    A new family of morphotropic phase boundary (MBP) perovskite solid solutions based on (1-x)BiMeO3-xPbTiO3 has been discovered. These materials promise both high piezoelectric properties, characteristic of MPB systems, and usage temperatures unavailable in current high performance piezoelectric systems. The discovery of this family of bismuth perovskite-lead titanate materials was made using simple crystal chemistry arguments based on the perovskite tolerance factor. In the current work, the details of the (1-x)BiScO3-xPbTiO3 (BSxPT) solid solution will be presented as the "prototype" example of this new family of materials. The optimum processing conditions and electromechanical properties of the BSxPT system were determined. X-ray diffraction, electron microscopy, dielectric measurements, and calorimetery were used to determine the details of the phase diagram, crystal structure, and domain structure. The intrinsic and extrinsic contributions to the dielectric and piezoelectric properties were determined using cryogenic dielectric measurements and a novel application of the Rayleigh Law to the direct piezoelectric response. The nature of the phase transition behavior in the tetragonal region of the BSxPT phase diagram was explored based on the Landau phenomenological approach. The BSxPT system represents a breakthrough in the field of piezoelectric ceramics. For the first time ever, a MPB piezoelectric material system has been developed with a transition temperature higher than Pb(Zr,Ti)O3 and improved piezoelectric properties. A detailed understanding of the structure, electromechanical response, and phase transition behavior of this exciting new system has been obtained. Further, a roadmap for the continued development of new materials in the family (1-x)BiMeO3-xPbTiO 3 was developed.

  3. 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.

  4. 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.

  5. OPTICAL AND PIEZOELECTRIC PROPERTIES OF TRANSPARENT PZN-PLZT CERAMICS

    Microsoft Academic Search

    GUOCHU DENG; AILI DING; XIA ZENG; TAO LIU; XINSEN ZHENG

    2006-01-01

    0.3Pb(Zn1\\/3Nb2\\/3)O3-0.7Pb0.96La0.4(ZrxTi1?x)O3(PZN-PLZT, x = 0.5?0.53) transparent piezoelectric ceramics with high density and pure perovskite have been synthesized by a two-stage hot-pressing procedure. The bulk densities of the specimens were measured by Archimedes method, and they are very close (> 99%) to the theoretical density. With the Zr\\/Ti ratios varying from 50\\/50 to 53\\/47, the d33 and kp show an ascending and

  6. 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).

  7. 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.

  8. 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.

  9. Microstructure Control of Barium Titanate Grain-oriented Ceramics and Their Piezoelectric Properties

    NASA Astrophysics Data System (ADS)

    Mori, Rintaro; Nakashima, Koichi; Fujii, Ichiro; Hayashi, Hiroshi; Nagamori, Yoshitaka; Yamamoto, Yuichi; Wada, Satoshi

    2011-10-01

    The Barium titanate (BaTiO3, BT) [110] grain-oriented ceramics along [110] direction were prepared by a templated grain growth (TGG) method. The [110] oriented BT platelike particles (t-BT) were used as template particles. The relationship between poling treatment program and piezoelectric constant was investigated. The change in the poling conditions did not greatly influence domain size and the piezoelectric constant. The relationship between piezoelectric properties and domain size in BT grain-oriented ceramics was investigated. The smaller domain size was required to increase the piezoelectric constant.

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

    NASA Astrophysics Data System (ADS)

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

    2011-10-01

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

  11. Properties of 1-3-2 connectivity piezoelectric ceramic/polymer composite

    NASA Astrophysics Data System (ADS)

    Liao, Shuangshuang; Huang, Shifeng; Xu, Dongyu; Cheng, Xin

    2009-07-01

    Epoxy resin and lead zirconate titanate (P-41) ceramic were respectively used as matrix and functional component to fabricate 1-3 and 1-3-2 connectivity piezoelectric ceramic-polymer composites by dice and filling method. The interface bonding condition between matrix and piezoelectric functional phase was investigated by using SEM. Piezoelectric properties, dielectric properties, electromechanical properties and acoustic impedance of the 1-3 and 1-3-2 connectivity piezoelectric composites were studied. The results show that the interface bonding of the two-phase materials is compact, comparing with the P-41 ceramic, the thickness electromechanical coupling coefficient Kt of both kinds of the composites is almost two times larger than that of P-41 ceramic, while the value of mechanical quality factor Qm and dielectric loss tan? are smaller, acoustic impedance Z and relative dielectric constant ?r are almost half of P-41 ceramic. The value of d33, g33, Kt, Qm, Z, ?r, and tan? of 1-3-2 connectivity piezoelectric composite are close to those of 1-3 connectivity piezoelectric composite, which show that the 1-3-2 connectivity piezoelectric composite can instead of 1-3 connectivity piezoelectric composite in special application field.

  12. 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.

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

    PubMed

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

    2011-10-01

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

  14. Behavior of soft piezoelectric ceramics under high sinusoidal electric fields

    NASA Astrophysics Data System (ADS)

    Kugel, V. D.; Cross, L. E.

    1998-09-01

    The behavior of piezoelectric, dielectric, and elastic characteristics of soft piezoelectric lead zirconate titanate (PZT) ceramics was investigated under sinusoidal electric field E applied along the poling direction and under mechanical stress-free conditions for a frequency range 10 Hz-10 kHz. Electrical displacement D3 along the poling direction, mechanical strain S1 in the direction perpendicular to the poling direction, and the resonant frequency ?r of electromechanically uncoupled bending vibrations of polarized plates were measured. Commercial ceramics PZT5H, 3203HD, and PKI550 with chemical composition near the morphotropic phase boundary were used in the study. It was found that the amplitude and phase of the first harmonic of the relative strain S1(1)/Em and of the relative electrical displacement D3(1)/Em increase similarly with increasing amplitude Em of the electric field if the amplitude is less than coercive field. The corresponding increase in the square of the resonant frequency is more moderate. The dependencies are described well by linear functions except for low electric fields. The functions S1m(1)/Em and D3m(1)/Em demonstrate frequency dispersion as well. Relative amplitude of the second harmonic of the electrical displacement, D3m(2)/D3m(1), which is polar, also increases almost linearly with increasing Em. The relative third harmonic D3m(3)/D3m(1) demonstrates saturationlike behavior. By means of the electric pulse technique, it was found that irreversible changes in the remnant polarization take place even at electric fields much smaller that the coercive field. A mathematical model of a hysteretic transducer, describing the electric field dependence of electromechanical properties of soft piezoelectric PZT ceramics, was suggested. According to this approach, the response depends not only on the instantaneous magnitude of the input signal (e.g., electric field) but also on its past extreme values. It was shown that the experimental Rayleigh law is a particular case of the suggested approach. The model relates directly electric field dependencies of complex piezoelectric coefficient d31(Em) and S1(1)/Em, of complex dielectric permittivity ?33T(Em) and D3(1)/Em, and of the amplitude of elastic compliance s11E(Em) and ?r2. Application of the model to experimental data showed that the model describes well the first three complex harmonics of D3 and the irreversible change in the remnant polarization. Physical causes of the observed behavior were analyzed. As an alternative to the model based on the 90 polarization reorientation and tetragonal/rhombohedral phase boundary motion, a new approach was suggested. In this model, the observed hysteretic changes in the electromechanical properties are assumed to be caused by the electric field dependency of the mechanical stress acting at interdomain boundaries in the partly constrained crystallites of these ceramics.

  15. 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.

  16. 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 adsorptiondesorption 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.

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

    PubMed

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

    2011-09-01

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

  18. Compositional effect on piezoelectric and anomalous photovoltaic properties of PLZT ceramics with fixed grain sizes

    Microsoft Academic Search

    Jing-Feng Li; Daming Cheng

    2008-01-01

    Lanthanum-modified lead zirconate titanate (PLZT) ceramics possess the photostrictive effect applicable to photo-driven and\\u000a wireless actuators. The piezoelectric and anomalous photovoltaic (APV) properties of PLZT ceramics with different compositions\\u000a but the same grain size were evaluated to investigate the intrinsic compositional effects. After the adjustment of the sintering\\u000a temperature and soaking time, the grain sizes of PLZT ceramics with different

  19. 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).

  20. 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].

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

    NASA Astrophysics Data System (ADS)

    Dong, Biqin

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

  2. 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.

  3. Electric fracture and polarization switching properties of piezoelectric ceramic PZT studied by the modified small punch test

    Microsoft Academic Search

    Y. Shindo; F. Narita; K. Horiguchi; Y. Magara; M. Yoshida

    2003-01-01

    The fracture behavior of a piezoelectric ceramic under applied electric fields has been discussed through experimental and theoretical characterizations. The modified small punch (MSP) tests were performed on a commercial piezoelectric ceramic. The fracture initiation loads under different electric fields were obtained from the experiment. Fracture surface was examined for the MSP specimens to identify the failure mechanisms under high

  4. Piezoelectric properties of polymer-piezoelectric ceramic composites crystallized under the action of an electric-discharge plasma

    NASA Astrophysics Data System (ADS)

    Kurbanov, M. A.; Sultanakhmedova, I. S.; Geidarov, G. M.; Aliev, G. G.

    2009-07-01

    The crystallization of a polymer-piezoelectric ceramic composite under the action of electric-discharge temperature and plasma is shown to cause strong oxidation of polymer chains, which increases the concentration of charge localization centers or the number of local levels in the quasi-bandgap of the polymer phase in the composite. In turn, this oxidation is accompanied by an increase in the interphase charges during electrothermal polarization, which favor effective polarization of piezophase domains and, hence, an increase in the piezoelectric properties. The degree of oxidation of the polymer phase is found to be controlled by the nature of the electric discharges used for composite crystallization. It is experimentally shown that piezoelectric composites should be crystallized under the action of a microdischarge that does not reach the streamer phase of its development. The optimum crystallization conditions are determined.

  5. Low-cost and easy experiment to study the electromechanical resonance of piezoelectric ceramics

    Microsoft Academic Search

    A. Santana-Gil; A. Pelaiz-Barranco; L. Rodriguez-Lopez

    2005-01-01

    An easy and low-cost experiment is presented to characterize the electromechanical resonance of piezoelectric ceramics. By using virtual instrumentation two instruments are substituted simultaneously: an oscilloscope and a frequency-meter. This is accomplished by using a personal computer, a data acquisition card and LabVIEW as programming environment. The experiment has been developed as a contribution to improve the researchers on piezoelectric

  6. Piezoelectric properties of polymer-piezoelectric ceramic composites crystallized under the action of an electric-discharge plasma

    Microsoft Academic Search

    M. A. Kurbanov; I. S. Sultanakhmedova; G. M. Geidarov; G. G. Aliev

    2009-01-01

    The crystallization of a polymer-piezoelectric ceramic composite under the action of electric-discharge temperature and plasma\\u000a is shown to cause strong oxidation of polymer chains, which increases the concentration of charge localization centers or\\u000a the number of local levels in the quasi-bandgap of the polymer phase in the composite. In turn, this oxidation is accompanied\\u000a by an increase in the interphase

  7. Piezoelectric properties of polymer-piezoelectric ceramic composites crystallized under the action of an electric-discharge plasma

    Microsoft Academic Search

    M. A. Kurbanov; I. S. Sultanakhmedova; G. M. Geidarov; G. G. Aliev

    2009-01-01

    The crystallization of a polymer-piezoelectric ceramic composite under the action of electric-discharge temperature and plasma is shown to cause strong oxidation of polymer chains, which increases the concentration of charge localization centers or the number of local levels in the quasi-bandgap of the polymer phase in the composite. In turn, this oxidation is accompanied by an increase in the interphase

  8. Mechanical Reinforcement and Piezoelectric Properties of PZT Ceramics Embedded with Nano-Crystalline

    NASA Astrophysics Data System (ADS)

    Wang, Da-Wei; Jin, Hai-Bo; Yuan, Jie; Wen, Bao-Li; Zhao, Quan-Liang; Zhang, De-Qing; Cao, Mao-Sheng

    2010-04-01

    The double-scale lead zirconate titanate (PZT) piezoelectric ceramics were prepared by the solid state processing with PZT nano-crystalline and micro-powder. The microstructures, electrical and mechanical properties of the double-scale PZT are investigated. All the sintered ceramics exhibit a single perovskite structure and the grain size of the double-scale PZT reduces due to the incorporation of PZT nano-crystalline. Compared to normal PZT, the mechanical properties increase significantly and the piezoelectric properties decrease slightly. Mechanisms responsible for the reinforcement of the double-scale PZT are discussed.

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

    PubMed

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

    2004-11-01

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

  10. Preisach modeling of piezoelectric nonlinearity in ferroelectric ceramics

    Microsoft Academic Search

    G. Robert; D. Damjanovic; N. Setter; A. V. Turik

    2001-01-01

    Piezoelectric response nonlinearity is approached using the Preisach description of hysteretic systems as collection of distributed bistable units. The Preisach model and its recent physical interpretation in terms of moving domain wall in a stochastically described pinning field are reviewed. It is shown that such an approach can effectively render not only the piezoelectric coefficient field dependences but also the

  11. Aurivillius ceramics: Bi4Ti3O12-based piezoelectrics

    Microsoft Academic Search

    T. JARDIEL; A. C. CABALLERO; M. VILLEGAS

    2008-01-01

    Aurivillius oxides family has attracted great interest in the last years due to their promising electrical properties as high tem- perature piezoelectric materials. Piezoelectric materials that could operate in extreme conditions of use (elevated temperatures and hostile environments) could be of particular interest for different technological applications. Furthermore, increasing con- cerns for environmental issues have promoted the study of new

  12. Mechanical Reinforcement and Piezoelectric Properties of PZT Ceramics Embedded with NanoCrystalline

    Microsoft Academic Search

    Da-Wei Wang; Hai-Bo Jin; Jie Yuan; Bao-Li Wen; Quan-Liang Zhao; De-Qing Zhang; Mao-Sheng Cao

    2010-01-01

    The double-scale lead zirconate titanate (PZT) piezoelectric ceramics were prepared by the solid state processing with PZT nano-crystalline and micro-powder. The microstructures, electrical and mechanical properties of the double-scale PZT are investigated. All the sintered ceramics exhibit a single perovskite structure and the grain size of the double-scale PZT reduces due to the incorporation of PZT nano-crystalline. Compared to normal

  13. Dielectric constant tunability at microwave frequencies and pyroelectric behavior of lead-free submicrometer-structured (Bi0.5Na0.5)1-xBaxTiO3 ferroelectric ceramics.

    PubMed

    Martnez, Flix L; Hinojosa, Juan; Domnech, Gins; Fernndez-Luque, Francisco J; Zapata, Juan; Ruiz, Ramon; Pardo, Lorena

    2013-08-01

    In this article, we show that the dielectric constant of lead-free ferroelectric ceramics based on the solid solution (1-x)(Bi(0.5)Na(0.5))TiO(3)-xBaTiO(3), with compositions at or near the morphotropic phase boundary (MPB), can be tuned by a local applied electric field. Two compositions have been studied, one at the MPB, with x = 0.06 (BNBT6), and another one nearer the BNT side of the phase diagram, with x = 0.04 (BNBT4). The tunability of the dielectric constant is measured at microwave frequencies between 100 MHz and 3 GHz by a nonresonant method and simultaneously applying a dc electric field. As expected, the tunability is higher for the composition at the MPB (BNBT6), reaching a maximum value of 60% for an electric field of 900 V/cm, compared with the composition below this boundary (BNBT4), which saturates at 40% for an electric field of 640 V/cm. The high tunability in both cases is attributed to the fine grain and high density of the samples, which have a submicrometer homogeneous grain structure with grain size of the order of a few hundred nanometers. Such properties make these ceramics attractive for microwave tunable devices. Finally, we have tested these ceramics for their application as infrared pyroelectric detectors and we have found that the pyroelectric figure of merit is comparable to traditional lead-containing pyroelectrics. PMID:25004530

  14. 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.

  15. C-Mode Ultrasonic System Based in Piezoelectric Ceramics and PVDF Polymers for Several Acoustic Impedances

    Microsoft Academic Search

    L. Rivera Galvn; R. Rodrguez Ruiz; E. Suaste Gmez

    2006-01-01

    The present paper provides a basic ultrasonic system based in a C-mode using a piezoelectric ceramic as a transmitter and a PVDF polymer as receiver and its behavior in several acoustic impedances in order to establish this system as a novel way for ultrasonic applications. This paper provides experimental results about how is the ultrasonic signal affected in several acoustic

  16. The investigation of depoling mechanism of densified KNbO{sub 3} piezoelectric ceramic

    SciTech Connect

    Ge Haiyan; Hou Yudong; Rao Xue; Zhu Mankang; Wang Hao; Yan Hui [Department of Materials Science and Engineering, Beijing University of Technology, Beijing 100124 (China)

    2011-07-18

    Thermal depoling phenomena determine the upper temperature limit of the piezoelectric ceramics in application. In this paper, high-densified KNbO{sub 3} ceramics derived from single-crystalline nanostructures exhibited favorable piezoelectric constants d{sub 33}, which varied from 105 to 80 pC/N over a broad temperature range from 25 to 225 deg. C. In situ x-ray diffraction combined with Raman spectra demonstrate clearly the transition sequence of crystallographic orientations during thermal depoling process. The interaction between defect dipoles D and spontaneous polarization inside domains P{sub s} favored to preserve piezoelectric activity, while the spontaneous rotation of P{sub s} induced by the phase transition resulted in the deliquesce of d{sub 33}.

  17. 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 [School of Engineering and Materials Science, Queen Mary University of London, London E1 4NS (United Kingdom); Department of Materials, University of Oxford, Oxford OX1 3PH (United Kingdom); Yan Haixue; Reece, Michael J. [School of Engineering and Materials Science, Queen Mary University of London, London E1 4NS (United Kingdom); Nanoforce Technology Ltd., London E1 4NS (United Kingdom)

    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.

  18. A comparison of single crystal versus ceramic piezoelectric materials for acoustic applications

    NASA Astrophysics Data System (ADS)

    Tressler, James F.

    2003-04-01

    For nearly fifty years, piezoelectric ceramics (primarily from the PZT family) have been the materials of choice as the active elements in sound projectors and receivers, medical ultrasound probes, etc. There is currently great interest in the materials community in the use of newly discovered single crystal relaxor ferroelectric materials as a replacement in applications that currently utilize piezoelectric ceramics. The salient features of single crystal piezoelectrics are strains an order of magnitude larger than are achievable in PZT and electromechanical coupling coefficients on the order of 90 percent. This presentation will provide a more thorough comparison of the physical and piezoelectric properties of single crystal piezoelectrics versus conventional PZT piezoceramics. This will hopefully provide the transducer designer with a better understanding of the pros and cons in the use of single crystals. In addition, a brief review of single crystal synthesis procedures will be described. Finally, some acoustic devices utilizing both single crystals and piezoceramics will be compared. [Work supported by DARPA and ONR Code 321-TS.

  19. Investigation on dielectric and piezoelectric characterization of PLSZT-BT ceramics

    NASA Astrophysics Data System (ADS)

    Ramam, K.; Chandramouli, K.

    2008-06-01

    In this paper, the ceramic compositions (1-x)Pb{1-w-y}La{w}Sr{y}(Zr{z}Ti{1-z})(1-w/4)O{3}-xBaTiO{3}, where x = 0.15, 0.25, 0.35 and 0.45, fabricated through solid state reaction method were investigated for phase formation, microstructure, density, dielectric and piezoelectric properties. The combination of the two perovskite structured stoichiometric compositions (i.e., isovalent Sr2+ modified PLZT and BaTiO{3}) indicated that tetragonality enhanced further due to BaTiO{3} concentration in PLSZT lattice. The BaTiO{3} in PLSZT ceramics were homogeneously distributed within the two perovskite structured solid solutions. The dielectric characterization indicated that \\varepsilon RT enhanced while tan? RT and Tc decreased with increasing BT additions into PLSZT perovskite. The maximum \\varepsilon RT = 2986 and \\varepsilon T_c = 21468 were found in 0.55PLSZT-0.45BT ceramic system. The piezoelectric properties were influenced by both BaTiO{3} and Sr2+ modified PLZT perovskite. The influence of BT modified PLSZT ceramics showed significant variations that has been discussed. The piezoelectric properties remarkably enhanced with maximum (kp = 0.541 and d33 = 518 pC/N) values in the 0.55PLSZT-0.45BT composition and thus, could be a promising candidate among this series for possible capacitor, sensor and actuator applications.

  20. 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.

  1. Modeling of high-temperature ferroelectric-piezoelectric ceramics

    SciTech Connect

    Reznichenko, L.A.; Dergunova, N.V.; Razumovskaya, O.N. [Rostov State Univ. (Russian Federation)] [and others

    1995-06-01

    A designed high-temperature materials based on PZT (PKR-26, t{sub w} = 300{degrees}C), tetragonal potassium tungsten bronze (PKR-45, t{sub w} = 350{degrees}C), bismuth perovskites (PKR-50, t{sub w} = 500{degrees}C), and lithium metaniobate (PKR-61, t{sub w} = 950{degrees}C). These materials are potential candidates for use in piezoelectric sensors for the automobile industry, aircraft construction, ship building, metallurgy, and geology.

  2. The Charge-Free Zone Model for Conductive Cracks in Dielectric and Piezoelectric Ceramics

    Microsoft Academic Search

    Tong-Yi Zhang

    In the charge-free zone (CFZ) model, dielectric and piezoelectric ceramics are treated to be mechanically brittle and electrically\\u000a ductile. For an electrically conductive crack under electrical and\\/or mechanical loading, various charge emission mechanisms\\u000a may function jointly at the tip due to the high electric field concentration. Charge emission and charge trapping consume\\u000a more work and thus lead to a high

  3. 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.

  4. 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.

  5. 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.

  6. Hot-stage transmission electron microscopy study of (Na, K)NbO3 based lead-free piezoceramics

    NASA Astrophysics Data System (ADS)

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

    2014-07-01

    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, (Na0.52K0.48-x)(Nb0.95-xTa0.05)-xLiSbO3, 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.

  7. Strong anisotropy of ferroelectricity in lead-free bismuth silicate.

    PubMed

    Seol, Daehee; Taniguchi, Hiroki; Hwang, Jae-Yeol; Itoh, Mitsuru; Shin, Hyunjung; Kim, Sung Wng; Kim, Yunseok

    2015-07-21

    Bismuth silicate (Bi2SiO5) was recently suggested as a potential silicate based lead-free ferroelectric material. Here, we show the existence of ferroelectricity and explore the strong anisotropy of local ferroelectricity using piezoresponse force microscopy (PFM). Domain structures are reconstructed using angle-resolved PFM. Furthermore, piezoresponse hysteresis loops and piezoelectric coefficients are spatially investigated at the nanoscale. The obtained results confirm the existence of ferroelectricity with strong c-axis polarization. These results could provide basic information on the anisotropic ferroelectricity in Bi2SiO5 and furthermore suggest its considerable potential for lead-free ferroelectric applications with silicon technologies. PMID:26084633

  8. Intricate straining of manganese-doped (Bi0.5Na0.5)TiO3-BaTiO3-(Bi0.5K0.5)TiO3 lead-free ferroelectric ceramics

    NASA Astrophysics Data System (ADS)

    Shieh, J.; Lin, Y. C.; Chen, C. S.

    2010-01-01

    The strain hystereses of lead-free a(Bi0.5Na0.5)TiO3-bBaTiO3-c(Bi0.5K0.5)TiO3 (abbreviated as BNBK 100a/100b/100c) ferroelectric compositions inside and outside the morphotropic phase boundary (MPB) were investigated previously by the authors, and it was found that BNBK 85.4/2.6/12, a composition well within the MPB, possesses notable actuating properties such as an induced electrostrain of about 0.14%. In this study, BNBK 85.4/2.6/12 is doped with various amounts of manganese (Mn) to improve its sinterability and ferroelectric characteristics. Intricate strain hysteresis behaviours are observed upon Mn dopingan electrostrain of above 0.1% can be maintained when the Mn doping amount is between 0.5 and 1.5 mol%. Once outside this doping range, the induced electrostrain is considerably smaller. By examining the evolution of crystalline phase composition with Mn doping, the mole content of the rhombohedral phase is shown for the first time to be a critical factor in deciding the straining behaviours of the Mn-doped BNBK 85.4/2.6/12 ceramics. To each increasing step in Mn doping level, there is a marked similarity in the evolutions of the induced electrostrain and rhombohedral phase content. The rhombohedral ferroelectric phase possesses more equivalent crystallographic directions for non-180 polarization switching, and accordingly, the Mn-doped BNBK compositions with relatively higher rhombohedral phase contents exhibit larger electrostrains.

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

    NASA Astrophysics Data System (ADS)

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

    2013-04-01

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

  10. Enhanced ferroelectric and piezoelectric properties in doped lead-free (Bi0.5Na0.5)0.94Ba0.06TiO3 thin films

    NASA Astrophysics Data System (ADS)

    Wang, D. Y.; Chan, N. Y.; Li, S.; Choy, S. H.; Tian, H. Y.; Chan, H. L. W.

    2010-11-01

    Doping effects with respect to the electrical properties of morphotropic phase boundary (Bi0.5Na0.5)0.94Ba0.06TiO3 thin films epitaxially grown on CaRuO3 electroded (LaAlO3)0.3(Sr2AlTaO6)0.35 (001) substrates were investigated. Substantial enhancement of ferroelectricity and piezoelectricity has been achieved in La+Ce codoped films with a remanent polarization Pr of 29.5 ?C/cm2 and a remanent piezoelectric coefficient d33,f of 31 pm/V, whereas Mn doping seems more favorite to reduce the leakage current by two order of magnitude. Both doped films exhibited diodelike I-V characteristics, which are correlated with resistance switching effect.

  11. 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.

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

    PubMed Central

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

    2013-01-01

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

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

    PubMed

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

    2011-09-01

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

  14. Design of Total Sliding-Mode-Based Genetic Algorithm Control for Hybrid Resonant-Driven Linear Piezoelectric Ceramic Motor

    Microsoft Academic Search

    Rong-Jong Wai; Ching-Hsiang Tu

    2007-01-01

    This study presents a total sliding-mode-based genetic algorithm control (TSGAC) system for a linear piezoelectric ceramic motor (LPCM) driven by a newly designed hybrid resonant inverter. First, the motor configuration and driving circuit of an LPCM are introduced, and its hypothetical dynamic model is represented by a nonlinear function with unknown system parameters. In the hybrid resonant drive system, it

  15. Electric properties of Holmium substituted SrBi4Ti4O15ceramic for High Temperature Piezoelectric Applications

    Microsoft Academic Search

    P. Sarah

    2011-01-01

    Piezoelectric ceramics have been widely used for several applications, such as those in filters for mobile communications; resonators for microprocessors, actuators for inject printers and sensors for detecting shock and hard disc drives (HDDs). Recently the family Aurivillius Bismuth Layer-Structure Ferroelectrics (BLSFs) has received attention for their use in the nonvolatile Ferroelectric Random Access Memory (FeRAM). In addition BLSFs have

  16. 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.

  17. Theoretical study on the static performance of piezoelectric ceramic-polymer composites with 1-3 connectivity

    NASA Astrophysics Data System (ADS)

    Cao, Wenwu; Zhang, Q. M.; Cross, L. E.

    1992-12-01

    Inhomogeneous displacement profiles have been derived for a single-rod composite and a single-tube 1-3 ceramic-polymer composite under both uniaxial and hydrostatic stress. The effective piezoelectric constants for the composites have been derived in terms of the ceramic content, the piezoelectric and elastic constants of each component, and the aspect ratio of the ceramic rod. The stress concentration inside both phases is derived from the calculated inhomogeneous displacement profiles. It is found that only a finite portion of the polymer in the vicinity of the ceramic-polymer interface actually contributes to the stress transfer, and the induced additional stress on the ceramic also has a higher magnitude near the interface. The theoretical results quantitatively predict the performance of a given 1-3 structure, and can be used to optimize the design parameters, such as ceramic content, aspect ratio of the ceramic rods, rod geometry and rod arrangement, resin hardness, etc., for 1-3 structures designed for specific purposes.

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

    PubMed

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

    2011-09-01

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

  19. 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.

  20. Lead-free electric matches.

    SciTech Connect

    Son, S. F. (Steven F.); Hiskey, M. A. (Michael A.); Naud, D. (Darren); Busse, J. R. (James R.); Asay, B. W. (Blaine 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.

  1. Enhanced piezoelectric and pyroelectric effects in single-phase multiferroic Bi1-xNdxFeO3 (x=0-0.15) ceramics

    Microsoft Academic Search

    G. L. Yuan; Siu Wing

    2006-01-01

    Single-phase multiferroic Bi1-xNdxFeO3 (x=0-0.15) ceramics are polarized and their piezoelectric and pyroelectric effects are reported. The success in polarizing the ceramics originates from low electrical conductivities controlled predominantly by the Poole-Frenkel conduction mechanism. Limited internal traps due to reduced oxygen vacancies in the ceramics result in sufficiently low leakage current densities of <30 mA\\/m2 even at a high electric field

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

    PubMed

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

    2001-07-01

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

  3. Microstructure Design of Lead-Free Piezoelectric R. E. Garcia,,

    E-print Network

    Rohrer, Gregory S.

    University, West Lafayette, IN 47907-2044 : Toyota Research Institute of North America, Ann Arbor, MI 48105 : Toyota Central Research & Development Laboratories, Inc., Nagatuke, Aichi, 480-1190, Japan : Toyota

  4. 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.

  5. The effects of porosity, electrode and barrier materials on the conductivity of piezoelectric ceramics in high humidity and dc electric field

    NASA Astrophysics Data System (ADS)

    Weaver, P. M.; Cain, M. G.; Stewart, M.; Anson, A.; Franks, J.; Lipscomb, I. P.; McBride, J. W.; Zheng, D.; Swingler, J.

    2012-04-01

    Prolonged operation of piezoelectric ceramic devices under high dc electric fields promotes leakage currents between the electrodes. This paper investigates the effects of ceramic porosity, edge conduction and electrode materials and geometry in the development of low resistance conduction paths through the ceramic. Localized changes in the ceramic structure and corresponding microscopic breakdown sites are shown to be associated with leakage currents and breakdown processes resulting from prolonged operation in harsh environments. The role of barrier coatings in mitigating the effects of humidity is studied, and results are presented on improved performance using composite diamond-like carbon/polymer coatings. In contrast to the changes in the electrical properties of the ceramic, the measurements of the piezoelectric properties showed no significant effect of humidity.

  6. Preparation of [110] Grain Oriented Barium Titanate Ceramics by Templated Grain Growth Method and Their Piezoelectric Properties

    NASA Astrophysics Data System (ADS)

    Wada, Satoshi; Takeda, Kotaro; Muraishi, Tomomitsu; Kakemoto, Hirofumi; Tsurumi, Takaaki; Kimura, Toshio

    2007-10-01

    [110]-oriented barium titanate (BaTiO3) ceramics were prepared by templated grain growth (TGG) method using [110]-oriented BaTiO3 platelike particles as a template and hydrothermal BaTiO3 sphere particles with different particle sizes as a matrix. The degree of orientation along the [110] direction, F110, was measured using an X-ray diffraction (XRD) pattern by the Lotgering method. To obtain both a high density and a high F110, the preparation conditions were optimized as functions of matrix particle size, volume fraction of the template to the matrix, and sintering temperature. As for the results, BaTiO3-grain-oriented ceramics with a high density of more than 96% were successfully prepared despite various F110 values from 0 to 98%. Scanning electron microscopy (SEM) revealed that their average grain sizes were always approximately 75 ?m despite various F110 values and there were no anisotropic microstructures. These grain-oriented BaTiO3 ceramics were poled at 100 C, and their piezoelectric properties were measured using a resonance-antiresonance method and a piezo d33 meter for d31 and d33 piezoelectric constants. As for the results, the d31 values were almost constant at -50 pC/N despite various F110 values, while the d33 values increased with increasing F110 values, and at around an F110 of 85%, d33 reached a maximum of 788 pC/N.

  7. Study of polymorphic phase boundary in (Na,K,Li) (Nb,Ta,Sb)O3 piezoelectric ceramics

    NASA Astrophysics Data System (ADS)

    Zhao, Xiaokun; Zhang, Boping; Zhu, Lifeng; Zhao, Lei; Zhou, Pengfei

    2014-02-01

    Li, Ta and Sb co-doped (Na,K)NbO3 ceramics have been widely investigated due to the significantly enhanced piezoelectric properties attributed to the polymorphic phase transition (PPT). An empirical discriminant k = x/0.3 + y/0.3 + z/0.06 to estimate the PPT composition of Liz(Na0.5+?K0.5-?)1-zNb1-x-yTaxSbyO3 ceramics was deduced based on a displayed phase diagram between the phase structure and doping contents. The phase structure could be conveniently estimated by k, in which a PPT appeared in the vicinity of k = 1, crossing O symmetry at k < 1 and T symmetry at k > 1. Around k = 1, a series of LizNa0.52K0.48-zNb0.90Ta0.05Sb0.05O3 ceramics was prepared by a traditional solid-state reaction in a narrow range 0.03 ? z ? 0.05. A PPT at room temperature appeared critically in the z = 0.04 composition, indicating a good feasibility of the suggested empirical equation to determine the critical PPT composition in the present study. The optimized piezoelectric properties d33 255 pC N-1 and kp 35.0% were attained due to the PPT behaviour.

  8. Fundamental limitation to the magnitude of piezoelectric response of ?001?pc textured K0.5Na0.5NbO3 ceramic

    NASA Astrophysics Data System (ADS)

    Gupta, Shashaank; Belianinov, Alexei; Baris Okatan, Mahmut; Jesse, Stephen; Kalinin, Sergei V.; Priya, Shashank

    2014-04-01

    ?001?pc textured K0.5Na0.5NbO3 (KNN) ceramic was found to exhibit a 65% improvement in the longitudinal piezoelectric response as compared to its random counterpart. Piezoresponse force microscopy study revealed the existence of larger 180 and non-180 domains for textured ceramic as compared to the random ceramic. Improvement in piezoresponse by the development of ?001?pc texture is discussed in terms of the crystallographic nature of KNN and domain morphology. A comparative analysis performed with a rhombohedral composition suggested that the improvement in longitudinal piezoresponse of polycrystalline ceramics by the development of ?001?pc texture is determined by the crystal structure.

  9. EFFECT OF NIOBIUM DOPING ON PIEZOELECTRIC AND PYROELECTRIC PROPERTIES OF Bi3.5Nd0.5Ti3O12 CERAMICS

    Microsoft Academic Search

    T. T. HU; K. W. KWOK; H. L. W. CHAN; C. L. CHOY

    2006-01-01

    Niobium-doped bismuth titanate (Bi3.5?x\\/3Nd0.5Ti3?xNbxO12, x = 0 to 0.09) were prepared using a conventional mixed oxide method, and the effects of Nb doping on the dielectric, ferroelectric, piezoelectric and pyroelectric properties of the ceramics were examined. In general, the doping with Nb decreases the relative permittivity ?, coercive field Ec and leakage current density J of the ceramics, while increases

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

    NASA Astrophysics Data System (ADS)

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

    2008-11-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-01-01

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

  12. Effects of Lead Free Soldering on \\

    Microsoft Academic Search

    Jack Fellman

    The removal of lead from solder and solder pastes to make the manufacturing process of electronic devices more environmentally friendly has created more confusion and uncertainty in the electronics industry than any other single change in decades. The single greatest factor is the higher soldering temperature required for lead free alloys, whether for wave solder, surface mount reflow or rework.

  13. Piezoelectric, pyroelectric and dielectric properties of La and Sm-doped PZT ceramics

    Microsoft Academic Search

    C. Pramila; T. C. Goel; P. K. C. Pillai

    1993-01-01

    Pair-doped lead zirconate titanate (PZT) samples were prepared by introducing lanthanum (La) and samarium (Sm) into the PZT lattice. Three compositions of pair-doped PZT were prepared by a conventional method. The dielectric, piezoelectric and pyroelectric properties of these samples were studied and compared with that of PLZT(8\\/65\\/35) samples prepared under the same conditions. The piezoelectric and pyroelectric figures of merit

  14. THE PROLIFERATION OF LEAD-FREE ALLOYS

    Microsoft Academic Search

    Eric Bastow; Timothy Jensen

    2009-01-01

    The advent of the EU's RoHS law has encouraged a significant amount of research to find an alloy, for electronic assembly, that will satisfy RoHS's lead-free requirement and have optimum process ability and field reliability. The resulting research, much of it lead by iNEMI, resulted in the near eutectic tin-silver-copper alloy SAC387 (Sn95.5Ag3.8Cu 0.7) as an initial favorite to fill

  15. Note: a high-sensitivity current sensor based on piezoelectric ceramic Pb(Zr,Ti)O3 and ferromagnetic materials.

    PubMed

    He, Wei; Li, Ping; Wen, Yumei; Zhang, Jitao; Yang, Aichao; Lu, Caijiang

    2014-02-01

    An electric current sensor using piezoelectric ceramic Pb(Zr,Ti)O3 (PZT) sandwiched between two high permeability cuboids and two NdFeB magnets is presented. The magnetic field originating from an electric wire is augmented by the high permeability cuboids. The PZT plate experiences an enhanced magnetic force and generates voltage output. When placed with a distance of d = 5.0 mm from the wire, the sensor shows a flat sensitivity of ?5.7 mV/A in the frequency range of 30 Hz-80 Hz and an average sensitivity of 5.6 mV/A with highly linear behavior in the current range of 1 A-10 A at 50 Hz. PMID:24593410

  16. Ultrasonic imaging system using a leaky surface acoustic wave transducer composed of piezoelectric ceramic and fused quartz

    NASA Astrophysics Data System (ADS)

    Toda, Kohji; Sawaguchi, Akihiro

    1991-01-01

    An ultrasonic imaging system is described by using a leaky surface acoustic wave (SAW) transducer composed of a piezoelectric ceramic thin plate/interdigital transducer/fused quartz. It is shown, both numerically and experimentally, that three operation modes of the transducer at a water-solid interface are available. Each of the three modes has a different operation frequency range, corresponding to the leaky SAW velocity. The bulk wave in water as an acoustical coupler between the tansducer and a tested object has a frequency-dependent angle relation; therefore, the acoustic beam steering is easily controlled and flexible in design. The reflection type of C-mode ultrasonic imaging results are demonstrated and are promising for nondestructive testing.

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

    SciTech Connect

    Mukherjee, Binu [Department of Physics, Royal Military College of Canada, Kingston, Ontario K7K 7B4 (Canada)

    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.

  18. 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.

  19. Structured Piezoelectric Composites: Materials and Applications

    Microsoft Academic Search

    D. A. Van den Ende

    2012-01-01

    The piezoelectric effect, which causes a material to generate a voltage when it deforms, is very suitable for making integrated sensors, and (micro-) generators. However, conventional piezoelectric materials are either brittle ceramics or certain polymers with a low thermal stability, which limits their practical application to certain specific fields. Piezoelectric composites, which contain an active piezoelectric (ceramic) phase in a

  20. Preparation and piezoelectric properties of textured PZT ceramics using PZT nano fibers

    Microsoft Academic Search

    Cai-feng Chen; Xiao-li Han; Jun Liu; Zhi-dan Ding

    2011-01-01

    PZT nano piezoelectric fibers were prepared by hydrothermal-template method. The effects of some reaction conditions on preparation were investigated, such as PH value, reaction temperature and time. The optimal hydrothermal conditions for preparing PZT nano fibers are that pH value is 13, reaction temperature is 190 C, hydrothermal reactor filling degree is 60 %70 %, reaction time is 10h, and

  1. Piezoelectric ceramic bimorph coupled to thin metal plate as cooling fan for electronic devices

    Microsoft Academic Search

    Ju Hyun Yoo; Jae Il Hong; Wenwn Cao

    2000-01-01

    Several types of piezoelectric fans for cooling electronic devices were constructed and tested at 60 Hz, 110 V and 220 V, respectively. The aim of the work is to investigate the possibility of replacing the rotary type of fan in some noise-sensitive electronic devices. Different vibrating metal plates were tested and analyzed theoretically. It is found that the resonant frequency

  2. Lead-free piezoceramics with giant strain in the system Bi{sub 0.5}Na{sub 0.5}TiO{sub 3}-BaTiO{sub 3}-K{sub 0.5}Na{sub 0.5}NbO{sub 3}. I. Structure and room temperature properties

    SciTech Connect

    Zhang, S.-T.; Kounga, Alain Brice; Aulbach, Emil; Granzow, Torsten; Jo, Wook; Kleebe, Hans-Joachim; Roedel, Juergen [Institute of Materials Science, Technische Universitaet Darmstadt, Petersenstr. 23, 64287 Darmstadt (Germany)

    2008-02-01

    Lead-free piezoelectric ceramics (1-x-y)Bi{sub 0.5}Na{sub 0.5}TiO{sub 3}-xBaTiO{sub 3}-yK{sub 0.5}Na{sub 0.5}NbO{sub 3} (0.05{<=}x{<=}0.07 and 0.01{<=}y{<=}0.03), have been synthesized by a conventional solid state sintering method. The room temperature ferroelectric and piezoelectric properties of these ceramics were studied. Based on the measured properties, the ceramics were categorized into two groups: group I compositions having dominant ferroelectric order and group II compositions displaying mixed ferroelectric and antiferroelectric properties at room temperature. A composition from group II near the boundary between these two groups exhibited a strain as large as {approx}0.45% at an electric field of 8 kV/mm. Polarization in this composition was not stable in that the piezoelectric coefficient d{sub 33} at zero electric field was only about 30 pm/V. The converse piezoelectric response becomes weaker when the composition deviated from the boundary between the groups toward either the ferroelectric or antiferroelectric compositions. These results were rationalized based on a field induced antiferroelectric-ferroelectric phase transition.

  3. Fundamental limitation to the magnitude of piezoelectric response of (001)pc textured K0.5Na0.5NbO3 ceramic

    SciTech Connect

    Gupta, Shashaank [ORNL] [ORNL; Belianinov, Alex [ORNL] [ORNL; Okatan, Mahmut B [ORNL] [ORNL; Jesse, Stephen [ORNL] [ORNL; Kalinin, Sergei V [ORNL] [ORNL; Priya, Shashaank [Virginia Tech] [Virginia Tech

    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.

  4. A three-phase magnetoelectric composite of piezoelectric ceramics, rare-earth iron alloys, and polymer

    Microsoft Academic Search

    C.-W. Nan; L. Liu; N. Cai; J. Zhai; Y. Ye; Y. H. Lin; L. J. Dong; C. X. Xiong

    2002-01-01

    A class of multiferroic, three-phase particulate composites of Tb-Dy-Fe alloy, lead-zirconate-titanate (PZT), and polymer are investigated, in which a small volume fraction f of Tb-Dy-Fe alloy particles are dispersed in a PZT\\/polymer mixture. The measured dielectric, piezoelectric, and magnetoelectric properties demonstrate that a percolation transition occurs at f~0.12 in the composites. When f is low (e.g., f<0.07), the composites exhibit

  5. EXAFS studies of the local atomic structure of the lead-free piezoelectric ceramics K{sub x}Na{sub 1-x}NbO{sub 3} over the temperature range 10-1023 K

    SciTech Connect

    Lemeshko, M. P.; Gonchar, A. A.; Reznichenko, L. A.; Nedoseykina, T. I.; Novakovich, A. A.; Vedrinskii, R. V. [Institute of Physics at Southern Federal University, 194 Stachky Avenue, Rostov-on-Don 344090 (Russian Federation); Nazarenko, E. S. [Institute of Physics at Southern Federal University, 194 Stachky Avenue, Rostov-on-Don 344090 (Russian Federation); Institut Neel and CNRS Associe a l'Universite Joseph Fourier, Boite Postale 166, F-38042 Grenoble Cedex 9 (France); Mathon, O. [BM29, European Synchrotron Radiation Facility, Boite Postale 220, F-38043 Grenoble Cedex 9 (France); Joly, Y. [Institut Neel and CNRS Associe a l'Universite Joseph Fourier, Boite Postale 166, F-38042 Grenoble Cedex 9 (France)

    2007-10-01

    We use the x-ray absorption fine structure spectroscopy at Nb K edge to reveal the local atomic structure of K{sub x}Na{sub 1-x}NbO{sub 3} (PSN) solid solutions. The study is performed over the temperature range 10-1023 K for six different x values. We show that only the combined analysis of extended x-ray absorption fine structure and preedge fine structure provides complete and reliable information about the local structure of NbO{sub 6} octahedra. Such extensive treatment of the experimental data shows that the local structure of PSN could be described within the spherical model proposed earlier as a hypothesis for perovskite-type ferroelectric zirconates. We reveal that the Nb atoms are localized near their average positions on the sphere surfaces for all temperatures and x values. With regard to previous results we point out the features of microscopic structure common for PSN and perovskite-type zirconates.

  6. Manganese-modified BiScO3PbTiO3 piezoelectric ceramic for high-temperature shear mode sensor

    Microsoft Academic Search

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

    2005-01-01

    The bismuth-based perovskite solid solution (100?x)BiScO3?xPbTiO3 (BSPT) was investigated for use at temperatures up to 400 C and above. The high-temperature resistivity, together with dielectric and piezoelectric behaviors of the shear mode for manganese-modified BSPT ceramics near the morphotropic phase boundary composition were studied. The resistivity and time constant were found to be 3107 ? cm and 0.08 s, respectively,

  7. Manganese-modified BiScO3-PbTiO3 piezoelectric ceramic for high-temperature shear mode sensor

    Microsoft Academic Search

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

    2005-01-01

    The bismuth-based perovskite solid solution (100-x)BiScO3-xPbTiO3 (BSPT) was investigated for use at temperatures up to 400 C and above. The high-temperature resistivity, together with dielectric and piezoelectric behaviors of the shear mode for manganese-modified BSPT ceramics near the morphotropic phase boundary composition were studied. The resistivity and time constant were found to be 3107 Omega cm and 0.08 s, respectively,

  8. Enhanced dielectric and piezoelectric properties of xBaZrO3-(1-x)BaTiO3 ceramics

    NASA Astrophysics Data System (ADS)

    Dong, Liang; Stone, Donald S.; Lakes, Roderic S.

    2012-04-01

    xBaZrO3-(1-x)BaTiO3 solid solutions (x = 0, 0.04, 0.06, 0.08, 0.12, and 0.18) synthesized via conventional solid state reaction method exhibit piezoelectric coefficients comparable to those of "hard" PZT-8, PZT-4, and even "soft" PZT-5 A. Doping also improves the poling efficiency of xBaZrO3-(1-x)BaTiO3 ceramics. Study of temperature dependence of the dielectric and piezoelectric properties reveal the following. Doping lowered the Curie point but raised the temperatures of the other two transformations. The diffused phase transition behavior has been enhanced with increasing content of BaZrO3, but x ? 0.18 is not enough to show a relaxor behavior. Piezoelectric responses show peaks at transformation temperatures and exhibit the best stability in the orthorhombic phase. Significant improvement in room temperature piezoelectric and electromechanical responses (d33 = 420pC/N, d31 = -138pC/N, and kp = 49%) comparable to PZT-5 A is achieved at a composition of x = 0.06 (1400 C 100 h sintered), which brings the rhombohedral-orthorhombic transition to the ambient temperature. Enhanced piezoelectric properties are mainly attributed to a series of microscopic phase transformations due to the presence of internal structural gradient. Other possible contributions such as domain structures and constrained negative stiffness effect have also been discussed.

  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. [Department of Materials and Ceramics Engineering and CICECO, University of Aveiro, 3810-193 Aveiro (Portugal)] [Department of Materials and Ceramics Engineering and CICECO, University of Aveiro, 3810-193 Aveiro (Portugal); Amorin, Harvey; Alguero, Miguel [Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, 28049 Madrid (Spain)] [Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, 28049 Madrid (Spain)

    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. Lead-Free Surface Finishes for Electronic Components

    E-print Network

    Lead-Free Surface Finishes for Electronic Components: Tin Whisker Growth METALS This project degraded by the switch to lead- free technology. In particular, the state of compressive stress and the localized creep response (whisker growth) of tin-based lead-free electrodeposits are being measured

  11. Key reliability concerns with lead-free connectors

    Microsoft Academic Search

    Tadahiro Shibutani; Ji Wu; Qiang Yu; Michael G. Pecht

    2008-01-01

    This paper presents the key reliability issues of lead-free connectors. The paper first discusses electrical contact resistance of lead-free and lead-based solder-dipped contacts under various aging conditions. Then, the fretting corrosion of lead-free contacts is discussed. Finally, the reliability due to tin whiskers induced by mating pressure between connector contact elements is presented.

  12. Robust polarization and strain behavior of Sm-modified BiFeO3 piezoelectric ceramics.

    PubMed

    Walker, Julian; Budic, Bojan; Bryant, Peter; Kurusingal, Valsala; Sorrell, Charles C; Bencan, Andreja; Rojac, Tadej; Valanoor, Nagarajan

    2015-01-01

    The route to phase-pure BiFeO3 (BFO) ceramics with excellent ferroelectric and electromechanical properties is severely impeded by difficulties associated with the perovskite phase stability during synthesis. This has meant that dopants and solid solutions with BFO have been investigated as a means of not only improving the functional properties, but also of improving the perovskite phase formation of BFO-based ceramics. The present work focuses on Sm-modified BFO ceramics of composition Bi0.88Sm0.12FeO3. The polarization and strain behaviors were investigated as a function of the phase composition, microstructure, and chemical composition. Addition of Sm reduces the susceptibility of the BFO perovskite to phase degradation by Si impurities. Si was observed to react into Sm-rich grains dispersed within the microstructure, with no large increases in the amount of bismuth-parasitic phases, namely Bi25FeO39 and Bi2Fe4O9. These as-prepared ceramics exhibited robust polarization behavior showing maximum remnant polarizations of ~40 to 50 ?C/cm(2). The electric-fieldinduced strain showed an appreciable stability in terms of the driving field frequency with maximum peak-to-peak strains of ~0.3% and a coercive field of ~130 kV/cm. PMID:25585392

  13. Bright upconversion luminescence and increased Tc in CaBi{sub 2}Ta{sub 2}O{sub 9}:Er high temperature piezoelectric ceramics

    SciTech Connect

    Peng Dengfeng [Functional Materials Research Laboratory, Tongji University, 1239 Siping Road, Shanghai 200092 (China); National Institute of Advanced Industrial Science and Technology, Kyushu, 807-1 Shuku, Tosu, Saga 841-0052 (Japan); Wang Xusheng; Yao Xi [Functional Materials Research Laboratory, Tongji University, 1239 Siping Road, Shanghai 200092 (China); Xu Chaonan [National Institute of Advanced Industrial Science and Technology, Kyushu, 807-1 Shuku, Tosu, Saga 841-0052 (Japan); Lin Jian; Sun Tiantuo [College of Material Science and Engineering, Tongji University, 4800 Cao'an Highway, Shanghai 201804 (China)

    2012-05-15

    Er{sup 3+} doped CaBi{sub 2}Ta{sub 2}O{sub 9} (CBT) bismuth layered-structure high temperature piezoelectric ceramics were synthesized by the traditional solid state method. The upconversion (UC) emission properties of Er{sup 3+} doped CBT ceramics were investigated as a function of Er{sup 3+} concentration and incident pump power. A bright green upconverted emission was obtained under excitation 980 nm at room temperature. The observed strong green and weak red emission bands corresponded to the transitions from {sup 4}S{sub 3/2} and {sup 4}F{sub 9/2} to {sup 4}I{sub 15/2}, respectively. The dependence of UC emission intensity on pumping power indicated that a three-photon process was involved in UC emissions. Studies of dielectric with temperature have also been carried out. Introduction of Er increased the Curie temperature of CBT, thus, making this ceramic suitable for sensor applications at higher temperatures. Because of its strong up-converted emission and increased Tc, the multifunctional high temperature piezoelectric ceramic may be useful in high temperature sensor, fluorescence thermometry, and optical-electro integration applications.

  14. Effect of orthorhombic distortion on dielectric and piezoelectric properties of CaBi{sub 4}Ti{sub 4}O{sub 15} ceramics

    SciTech Connect

    Tanwar, Amit; Sreenivas, K.; Gupta, Vinay [Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India)

    2009-04-15

    High temperature bismuth layered piezoelectric and ferroelectric ceramics of CaBi{sub 4}Ti{sub 4}O{sub 15} (CBT) have been prepared using the solid state route. The formation of single phase material with orthorhombic structure was verified from x-ray diffraction and Raman spectroscopy. The orthorhombic distortion present in the CBT ceramic sintered at 1200 deg. C was found to be maximum. A sharp phase transition from ferroelectric to paraelectric was observed in the temperature dependent dielectric studies of all CBT ceramics. The Curie's temperature (T{sub c}=790 deg. C) was found to be independent of measured frequency. The behavior of ac conductivity as a function of frequency (100 Hz-1 MHz) at low temperatures (<500 deg. C) follows the power law and is attributed to hopping conduction. The presence of large orthorhombic distortion in the CBT ceramic sintered at 1200 deg. C results in high dielectric constant, low dielectric loss, and high piezoelectric coefficient (d{sub 33}). The observed results indicate the important role of orthorhombic distortion in determining the improved property of multicomponent ferroelectric material.

  15. Properties of Cerium Containing Lead Free Solder

    NASA Astrophysics Data System (ADS)

    Xie, Huxiao

    With increasing concerns of the intrinsic toxicity of lead (Pb) in electronics, a series of tin (Sn) based alloys involving silver (Ag) and copper (Cu) have been proposed as replacements for Pb-Sn solder and widely accepted by industry. However, they have a higher melting point and often exhibit poorer damage tolerance than Pb-Sn alloys. Recently, a new class of alloys with trace amount of rare-earth (RE) elements has been discovered and investigated. In previous work from Prof. Chawla's group, it has been shown that cerium (Ce)-based Pb-free solder are less prone to oxidation and Sn whiskering, and exhibit desirable attributes of microstructural refinement and enhanced ductility relative to lanthanum (La)-based Sn-3.9Ag-0.7Cu (SAC) alloy. Although the formation of RESn3 was believed to be directly responsible for the enhanced ductility in RE-containing SAC solder by allowing microscopic voids to nucleate throughout the solder volume, this cavitation-based mechanism needs to be validated experimentally and numerically. Additionally, since the previous study has exhibited the realistic feasibility of Ce-based SAC lead-free solder alloy as a replacement to conventional SAC alloys, in this study, the proposed objective focuses on the in in-depth understanding of mechanism of enhanced ductility in Ce-based SAC alloy and possible issues associated with integration of this new class of solder into electronic industry, including: (a) study of long-term thermal and mechanical stability on industrial metallization, (b) examine the role of solder volume and wetting behavior of the new solder, relative to Sn-3.9Ag-0.7Cu alloys, (c) conduct experiments of new solder alloys in the form of mechanical shock and electromigration. The research of this new class alloys will be conducted in industrially relevant conditions, and the results would serve as the first step toward integration of these new, next generation solders into the industry.

  16. Additive effects on electrical properties of (Bi 1\\/2Na 1\\/2)TiO 3 ferroelectric ceramics

    Microsoft Academic Search

    Hajime Nagata; Tadashi Takenaka

    2001-01-01

    Microstructure, dielectric, ferroelectric and piezoelectric properties of bismuth sodium titanate (Bi1\\/2Na1\\/2)TiO3 (BNT) were studied for a candidate as lead-free piezoelectric ceramics. In the case of Mn addition, the Curie temperature, Tc, decreases rapidly with increasing amount of doped MnCO3. The resistivity, ?, is enhanced to 31014 (?cm) (at 40C) for BNT+MnCO3 0.2 (wt.%) and electromechanical coupling factor, k33, was obtained

  17. 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

  18. Fabrication and electromechanical properties of microscale 1-3-type piezoelectric composites using (Na,K)NbO3-based Pb-free piezoceramics

    NASA Astrophysics Data System (ADS)

    Shen, Zong-Yang; Xu, Ying; Li, Jing-Feng

    2009-05-01

    Microscale 1-3-type piezoceramic/epoxy composites using Li/Ta-modified (Na,K)NbO3 (NKN-LT) lead-free piezoelectric ceramics were fabricated via a modified dice-fill method, by which the NKN-LT ceramic rods were miniaturized to a lateral width of 150 ?m with an aspect ratio (height/width) higher than 3.5. The piezoelectric properties of the 1-3 composites as a function of ceramic volume fraction were measured and compared with theoretical predictions. In addition to a high electromechanical coupling coefficient (kt50%) and low acoustic impedances (Z 10 Mrayls), the developed composites show a clear single thickness mode with a high resonance frequency over 3.5 MHz. The present Pb-free piezocomposites are suitable for medical imaging devices embedded in the human body.

  19. Lead-free solders and processing issues in microelectronics

    Microsoft Academic Search

    Raymond A. Fournelle; Lead-Free Solders

    2003-01-01

    ings on various aspects of lead-free solders R&D. Over 50 papers were presented dealing with fundamental studies, microstructure, alloy development, interfacial reactions, mechanical properties, physical metallurgy, solder joint reliability of lead-free solders, and solder joints. One unique trend of this symposium was a major emphasis on the leading lead-free candidates, namely, Sn-Ag-Cu alloy systems, and their use in microelectronic soldering.

  20. De-mystifying materials selection for lead-free soldering

    Microsoft Academic Search

    Casper Chen; Joshua Chiang; F. Y. Lee

    2006-01-01

    Purpose The lead-free soldering process has been confounding the PWB fabricators when they set out to select the right materials for lead-free soldering. This paper discusses the compatibility of currently available laminate materials for lead-free assembly. Design\\/methodology\\/approach This paper has been written to provide a review of material characteristics. Problem areas are highlighted and methods for choosing each

  1. Formation of intermetallics in lead-free systems

    Microsoft Academic Search

    M. Braunovic; D. Gagnon

    2004-01-01

    Formation and growth of intermetallics are one of the most important problem in the search for reliable lead-free alloys. Since the majority of the commercially available lead-free alloys contain high tin concentration, there is a long-term reliability concern due to tendency of tin to form intermetallics. A prolonged exposure to higher temperatures of lead-free alloys results in the continuous growth

  2. Experiments to demonstrate piezoelectric and pyroelectric effects

    NASA Astrophysics Data System (ADS)

    Erhart, Ji?

    2013-07-01

    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 change. The direct piezoelectric effect is demonstrated by the electric charge generated from the bending of the piezoelectric ceramic membrane or from the gas igniter. The converse piezoelectric effect is presented in the experiments by the deflection of the bending piezoelectric element (piezoelectric bimorph).

  3. Effect of high density and reduced ionic defects on piezoelectric behavior of K0.5Na0.5NbO3 ceramic

    NASA Astrophysics Data System (ADS)

    Gupta, Shashaank; Priya, Shashank

    2015-01-01

    A reduced concentration of ionic defects along with >99 % of the theoretical density has been achieved for K0.5Na0.5NbO3 ceramic by employing a twofold sintering technique. Lower concentration of ionic defects resulted in an order of magnitude improvement in the resistivity and hence enhanced poling of the ceramic at 100 C. High density and improved poling of the ceramic resulted in a significant improvement in electromechanical properties while maintaining the high orthorhombic-tetragonal ( T o-t) and Curie ( T c) temperatures of K0.5Na0.5NbO3 (200 and 395 C respectively). A comparison with the previous studies suggested that the piezoelectric properties of the ceramic synthesized in this study were similar to those synthesized using complex techniques such as spark plasma sintering and hot pressing. This is a significant advancement facilitating the possibility of transition of K0.5Na0.5NbO3 ceramic toward device application.

  4. 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.

  5. Effect of fretting in lead-free systems

    Microsoft Academic Search

    D. Gagnon; M. Braunovic

    2004-01-01

    Electrical performance characteristics of lead-free solders and their potential effects on the reliability of electronic connector separable interfaces is one of the problem areas that has to be addressed. Since fretting is inherent in practically all electronic and electrical connections it is the aim of this work to determine the effect of fretting in commercially available lead-free alloys. For this

  6. The current status of lead-free solder alloys

    Microsoft Academic Search

    D. Suraski; K. Seelig

    2001-01-01

    The issue of lead-free soldering has gripped the electronics assembly industry as of late. What was once something that appeared to be too far away to worry about now has become a pressing reality. In order to avoid confusion, panic, and a misunderstanding of how the issue of lead-free soldering will affect the industry and individuals, it is necessary for

  7. 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.

  8. 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.

  9. 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

  10. 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 [Department of Inorganic Chemistry, Arrhenius Laboratory, Stockholm University, S-106 91 Stockholm (Sweden); Department of Materials, Queen Mary University of London, Mile End Road, London E1 4NS (United Kingdom); Shanghai Institute of Ceramics, Chinese Academy of Science, 1295 Dingxi Road, Shanghai 200050 (China)

    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.

  11. An integrated microfluidic chip with 40 MHz lead-free transducer for fluid analysis.

    PubMed

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

    2011-02-01

    The design, fabrication, and evaluation of a high-frequency transducer made from lead-free piezoceramic for the application of microfluidic analysis is described. Barium strontium zirconate titanate [(Ba(0.95)Sr(0.05))(Zr(0.05)Ti(0.95))O(3), abbreviated as BSZT] ceramic has been chosen to be the active element of the transducer. The center frequency and bandwidth of this high-frequency ultrasound transducer have been measured to be 43 MHz and 56.1%, respectively. The transducer was integrated into a microfluidic channel and used to measure the sound velocity and attenuation of the liquid flowing in the channel. Results suggest that lead-free high-frequency transducers could be used for in situ analysis of property of the fluid flowing through the microfluidic system. PMID:21361626

  12. Unique single-domain state in a polycrystalline ferroelectric ceramic

    NASA Astrophysics Data System (ADS)

    Guo, Hanzheng; Zhou, Chao; Ren, Xiaobing; Tan, Xiaoli

    2014-03-01

    Non-180 ferroelectric domains are also ferroelastic domains; their existence in polycrystalline materials is to relieve internal stresses generated during solid-solid phase transitions and minimize the elastic distortion energy. Therefore, grains with random orientations in polycrystalline ceramics are always occupied by many domains, especially in the regions close to grain boundaries. In this Rapid Communication, we report the observation of a single-domain state in a BaTiO3-based polycrystalline ceramic at intermediate poling electric fields with in situ transmission electron microscopy. The grains in the virgin ceramic and under high poling fields are found multidomained. The unique single-domain state is believed to be responsible for the ultrahigh piezoelectric property observed in this lead-free composition and is suggested to be of orthorhombic symmetry for its exceptionally low elastic modulus.

  13. Prototyping of radially oriented piezoelectric ceramic-polymer tube composites using fused deposition and lost mold processing techniques

    NASA Astrophysics Data System (ADS)

    McNulty, Thomas Francis

    Piezoelectric tube composite hydrophones of 3-1, 3-2, and 2-2 connectivity were developed using Fused Deposition (FD) and lost mold processing (LMP). In this work, a new series of thermoplastic binder formulations, named the ECG series, were developed for the FD process. The ECG-9 formulation exhibits mechanical, thermal, and rheological properties suitable for the Fused Deposition of functional lead zirconate titanate ceramic devices. This binder consists of 100 parts (by weight) Vestoplast 408, 20 parts Escorez 2520, 15 parts Vestowax A-227, and 5 parts Indopol H-1500. Oleic acid, oleyl alcohol, stearic acid, and stearyl alcohol (in toluene) were tested for use as a dispersant in the PZT/ECG-9 system. It was found that stearic acid adsorbs the most onto PZT powder, adsorbing 8.1 mg/m2. Using stearic acid, solutions of increasing concentration (5.0--50.0 g/l) were measured for adsorption. It was found that 30.0 g/l is the minimum concentration necessary for optimum surface coverage. The surfactant-coated powder was compounded with ECG-9 binder to create a 54 vol.% mix. The mix was extruded using a single screw extrusion apparatus into continuous lengths (>30 m) of 1.78 mm diameter filament. Fused Deposition was used to create composite designs of 3-1, 3-2, and 2-2 connectivity. After sintering, samples exhibit a sintered density greater than 97%. Sanders Prototyping (SPI) was used to manufacture molds for use with LMP techniques. Molds of 3-1, 3-2, and 2-2 connectivity were developed. The molds were infiltrated with a 55 vol.% aqueous based PZT slurry. The parts were subjected to a binder decomposition cycle, followed by sintering. Resultant samples were highly variable due to random macro-pores present in the samples after sintering. The resultant preforms were embedded in epoxy, and polished to dimensions of 8.0 mm inside diameter (ID), 14.0 mm outside diameter (OD), and 10.0 mm length (l) the OD and l dimensions are accurate to +/--2%, while the ID is accurate to +/--5%. Samples were corona poled, and the electromechanical properties were evaluated. Dielectric constant (K), hydrostatic charge coefficients (dh), and radial displacements (ur) were measured. Of the seven composite types studied, the FD-based composites with 3-2 connectivity exhibited the highest average dh of 42.4 pCN. The same 3-2 composites exhibited the highest dhgh (FOM) of 140 fm2/N.

  14. Piezoelectric response and origin in ,,001... Pb,,Mg1/3Nb2/3...0.70Ti0.30O3 crystal C.-S. Tu,1,a

    E-print Network

    piezoelectric coefficients compared with lead zirconic titanate ceramics.1 Ferroelectric FE and piezoelectric Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 201800, People's Republic of China

  15. Reworking POP Package on Package in Lead-Free Array

    Microsoft Academic Search

    P. Wood

    2008-01-01

    In 2008 Lead Free Package POP (Package on Package) will be a major new device to hit the streets and will challenge many to re-evaluate their soldering and rework products\\/processes. The implementation of lead-free in the commercial world and is well on the way in assembly plants worldwide and particularly in Asia. This represents a major logistics risk to commercial

  16. Drop test reliability of lead-free chip scale packages

    Microsoft Academic Search

    Andrew Farris; Jianbiao Pan; Albert Liddicoat; Brian J. Toleno; Dan Maslyk; Dongkai Shangguan; Jasbir Bath; Dennis Willie; David A. Geiger

    2008-01-01

    This paper presents the drop test reliability of 0.5 mm pitch lead-free chip scale packages (CSPs). Fifteen 0.5 mm pitch CSPs were assembled on a standard JEDEC drop reliability test board with Sn3.0Ag0.5Cu lead-free solder. Eight boards were edge-bonded with a UV-cured acrylic; eight boards were edge- bonded with a thermal-cured epoxy; and twelve boards were assembled without edge bonding.

  17. Fretting corrosion studies for lead-free alloy plated contacts

    Microsoft Academic Search

    Ji Wu; Michael Pecht

    2002-01-01

    Determining the electrical characteristics of lead-free solder finishes, assessing the reliability of lead-free solder coatings while comparing their behavior to that of current tin-lead solder are necessary before implementing this material change in electronic separable connectors. Tin-lead solder alloys are the most commonly used non-noble contact finish materials in the electronic industry due to their low cost and ease of

  18. Novel Testing Instrument for Lead-Free Solder Characterization

    Microsoft Academic Search

    D. Di Maio; O. Thomas; M. Dusek; C. Hunt

    2011-01-01

    The European Union Restriction of Hazardous Sub- stances Directive of 2006 has revolutionized the use of materials for electronic packaging: tin-lead solder has had to be replaced with lead-free solder. While years of experience and data acquired in the field are available for tin-lead solder, the same cannot be said for lead-free solder. The lack of data on these new

  19. Lead-free reflow soldering for electronics assembly

    Microsoft Academic Search

    M. R. Harrison; J. H. Vincent; H. A. H. Steen

    2001-01-01

    Results for reflow soldering are presented from a three-year EC funded project IDEALS to develop lead-free soldering solutions. On the basis of fundamental data from the literature, a shortlist of candidate lead-free solders was selected, and results from tests on physical and soldering characteristics, and wetting balance testing, led to the choice of SnAg3.8Cu0.7, melting at 217C. Implications for solder

  20. Learning from the migration to lead-free solder

    Microsoft Academic Search

    Richard Ciocci; Michael Pecht

    2006-01-01

    Purpose The purpose of this paper is to characterize the motivations used into migrating to lead-free solder by providing examples and directions for those making the material change. Design\\/methodology\\/approach This work achieves its objective of identifying which electronic industry actions towards lead-free soldering have been successful and why. The research reported the various motivating factors considered in adopting

  1. Lead-free solder assembly: impact and opportunity

    Microsoft Academic Search

    E. Bradley

    2003-01-01

    Tlicrc Ius been major interest in Lead-free soldcring within the electronics assembly industry for the last scvcral years. and tlds will continue with the agrccmcnt on the languagc and implementation dates of the WEEWROHS lcgisliltiou in the EU. This paper will focus on several topics critical lo the implementation of lead-free soldering. Thesc topics include tlie impact of Tin-silver-copper as

  2. Effect of Y-doping on the piezoelectric properties of (1-x)BiScO3-xPbTiO3 high-temperature piezoelectric ceramics

    Microsoft Academic Search

    Qishou Li; Wei Shi; Yuzhi Jiang; Ying Pei; Qiang Chen; Xi Yue; Dingquan Xiao; Jianguo Zhu

    2009-01-01

    (1-x)Bi(Sc1-yYy)O3-xPbTiO3 (BSYPTx\\/y) ceramics were prepared by the conventional mixed oxide method. It was found that the morphotropic phase boundary (MPB) between rhombohedral and tetragonal phase of BSYPTx\\/y system was moved to the lower PT content with increasing of BiYO3 content. The Curie temperature (TC) near MPB of BSYPTx\\/y ceramics was found to increase with increasing of BiYO3 content. However, the

  3. 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 [Department of Electrical Engineering, National Cheng Kung University, Tainan 70101, Taiwan, ROC (China)] [Department of Electrical Engineering, National Cheng Kung University, Tainan 70101, Taiwan, ROC (China); Tsai, Cheng-Che [Department of Electronics Engineering and Computer Science, Tung-Fang Design University, Kaohsiung 82941, Taiwan, ROC (China)] [Department of Electronics Engineering and Computer Science, Tung-Fang Design University, Kaohsiung 82941, Taiwan, ROC (China); Hong, Cheng-Shong [Department of Electronic Engineering, National Kaohsiung Normal University, Kaohsiung County 824, Taiwan, ROC (China)] [Department of Electronic Engineering, National Kaohsiung Normal University, Kaohsiung County 824, Taiwan, ROC (China); Chu, Sheng-Yuan, E-mail: chusy@mail.ncku.edu.tw [Department of Electrical Engineering, National Cheng Kung University, Tainan 70101, Taiwan, ROC (China) [Department of Electrical Engineering, National Cheng Kung University, Tainan 70101, Taiwan, ROC (China); Center for Micro/Nano Science and Technology and Research Center for Energy Technology and Strategy, National Cheng Kung University, Tainan 701, Taiwan, ROC (China)

    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.

  4. 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.

  5. Enhanced electrical properties of textured NBBT ceramics derived from the screen printing technique.

    PubMed

    Wu, Mengjia; Wang, Youliang; Wang, Dong; Li, Yongxiang

    2011-10-01

    (001)(pc)-oriented (Na(0.5)Bi(0.5))(0.94)Ba(0.06)TiO(3) (NBBT) lead-free piezoelectric ceramics were fabricated by the screen printing technique using Na(0.5)Bi(0.5)TiO(3) (NBT) templates. The plate-like NBT template particles were synthesized from bismuth layer-structured ferroelectric Bi(4)Ti(3)O(12) (BiT) precursors by the topochemical method. The screen printed NBBT ceramics with 20 wt% NBT templates contained a large fraction of grains aligned with their c-axis normal to the sample surface, giving a Lotgering factor of 0.486. The dielectric and ferroelectric properties of textured NBBT ceramics were anisotropic. Compared with the non-textured NBBT ceramics, the dielectric, ferroelectric, and piezoelectric properties of the textured NBBT ceramics were improved, giving a dielectric constant ?(T)(33)/?(0) of 910, a remnant polarization P(r) of 29.2 ?C/cm(2), a coercive field E(c) of 23.5 kV/cm, a piezoelectric coefficient d(33) of 180 pC/N, and a thickness-mode electromechanical coupling coefficient k(t) of 0.485. PMID:21989867

  6. 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.

  7. Ferroelectric and piezoelectric properties of tungsten substituted SrBi{sub 2}Ta{sub 2}O{sub 9} ferroelectric ceramics

    SciTech Connect

    Coondoo, Indrani, E-mail: indrani_coondoo@yahoo.com; Agarwal, S.K. [Superconductivity and Cryogenics Division, National Physical Laboratory, Dr K.S. Krishnan Road, New Delhi 110012 (India); Jha, A.K. [Department of Applied Physics, Delhi College of Engineering, Bawana Road, Delhi 110042 (India)

    2009-06-03

    Tungsten substituted samples of compositions SrBi{sub 2}(W{sub x}Ta{sub 1-x}){sub 2}O{sub 9} (x = 0.0, 0.025, 0.050, 0.075, 0.10 and 0.20) were synthesized by solid-state reaction method and studied for their microstructural, electrical conductivity, ferroelectric and piezoelectric properties. The X-ray diffractograms confirm the formation of single phase layered perovskite structure in the samples with x up to 0.05. The temperature dependence of dc conductivity vis-a-vis tungsten content shows a decrease in conductivity, which is attributed to the suppression of oxygen vacancies. The ferroelectric and piezoelectric studies of the W-substituted SBT ceramics show that the remanent polarization and d{sub 33} values increases with increasing concentration of tungsten up to x {<=} 0.05. Such compositions with low conductivity and high P{sub r} values should be excellent materials for highly stable ferroelectric memory devices.

  8. Piezoelectric ceramic (PZT) modulates axonal guidance growth of rat cortical neurons via RhoA, Rac1, and Cdc42 pathways.

    PubMed

    Wen, Jianqiang; Liu, Meili

    2014-03-01

    Electrical stimulation is critical for axonal connection, which can stimulate axonal migration and deformation to promote axonal growth in the nervous system. Netrin-1, an axonal guidance cue, can also promote axonal guidance growth, but the molecular mechanism of axonal guidance growth under indirect electric stimulation is still unknown. We investigated the molecular mechanism of axonal guidance growth under piezoelectric ceramic lead zirconate titanate (PZT) stimulation in the primary cultured cortical neurons. PZT induced marked axonal elongation. Moreover, PZT activated the excitatory postsynaptic currents (EPSCs) by increasing the frequency and amplitude of EPSCs of the cortical neurons in patch clamp assay. PZT downregulated the expression of Netrin-1 and its receptor Deleted in Colorectal Cancer (DCC). Rho GTPase signaling is involved in interactions of Netrin-1 and DCC. PZT activated RhoA. Dramatic decrease of Cdc42 and Rac1 was also observed after PZT treatment. RhoA inhibitor Clostridium botulinum C3 exoenzyme (C3-Exo) prevented the PZT-induced downregulation of Netrin-1 and DCC. We suggest that PZT can promote axonal guidance growth by downregulation of Netrin-1 and DCC to mediate axonal repulsive responses via the Rho GTPase signaling pathway. Obviously, piezoelectric materials may provide a new approach for axonal recovery and be beneficial for clinical therapy in the future. PMID:24203571

  9. Lead-free solders with rare earth additions

    Microsoft Academic Search

    Fu Guo; Mengke Zhao; Zhidong Xia; Yongping Lei; Xiaoyan Li; Yaowu Shi

    2009-01-01

    AbstactThere have been significant research efforts to improve the properties of globally recognized lead-free solders, such as Sn-Ag-Cu,\\u000a Sn-Cu, Sn-Bi, etc. Rare earth (RE) elements have been selected in the current research to be added into lead-free solders\\u000a as alloying elements in an effort to improve the comprehensive properties, such as wettability, microstructural stability,\\u000a creep resistance, and mechanical strength and

  10. Structural and electrical properties of perovskite ruthenate-based lead-free thick film resistors on alumina and LTCC

    Microsoft Academic Search

    S. Rane; M. Prudenziati; B. Morten; L. Golonka; A. Dziedzic

    2005-01-01

    CaRuO3 perovskite-based lead-free thick-film resistors (TFRs) were prepared on 96%-alumina and Low Temperature Co-fired Ceramic (LTCC) substrates. The microstructure evolution, possible interactions, and electrical properties of resistors were investigated. The hot and cold TCR values of all the resistors were measured in the temperature range (+20 to +120 ?C) and (+20 to ?120 ?C), respectively. TFRs with 25% by vol.

  11. Hot Air Solder Leveling in the Lead-free Era

    Microsoft Academic Search

    Keith Sweatman

    2006-01-01

    Although the advantages of Hot Air Solder Leveling (HASL) in providing the most robust solderable finish for printed circuit boards are well recognized, in the years leading up to the implementation of the EU RoHS Directive in July 2006 the conventional wisdom was that it would have no place in the new lead-free electronics manufacturing technology. The widely promoted view

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

    SciTech Connect

    Patel, Piyush Kumar; Rani, Jyoti; Yadav, K. L. [Smart Materials Research Laboratory, Department of Physics Indian Institute of Technology, Roorkee-247667 (India)

    2012-06-05

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

  13. 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 (CuOKNN) 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 velocitytime 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 CuOKNN transducers could be determined and compared with those of Pb(Zr,Ti)O3 transducers.

  14. Elastic, dielectric, and piezoelectric anomalies and Raman spectroscopy of 0.5Ba(Ti0.8Zr0.2)O3-0.5(Ba0.7Ca0.3)TiO3

    NASA Astrophysics Data System (ADS)

    Damjanovic, Dragan; Biancoli, Alberto; Batooli, Leili; Vahabzadeh, Amirhossein; Trodahl, Joe

    2012-05-01

    The solid solution 0.5Ba(Ti0.8Zr0.2)O3-0.5(Ba0.7Ca0.3)TiO3 (BCZT) is a promising lead-free piezoelectric material with exceptionally high piezoelectric coefficients. The strong response is related to structural instabilities close to ambient temperature. We report here on temperature-induced anomalies in the dielectric, piezoelectric, and elastic coefficients and Raman spectroscopy of ceramic BCZT. The data indicate ferroelectric-ferroelectric structural phase transitions in this material in addition to those previously reported. An anomaly is also observed above the Curie temperature TC and is associated with the loss of polar structure that persists thirty degrees above TC.

  15. Ceramics

    NASA Astrophysics Data System (ADS)

    Yao, Lichun; Yang, Jian; Qiu, Tai

    2014-09-01

    The effects of CuO addition on phase composition, microstructure, sintering behavior, and microwave dielectric properties of 0.80Sm(Mg0.5Ti0.5)O3-0.20 Ca0.8Sr0.2TiO3(8SMT-2CST) ceramics prepared by a conventional solid-state ceramic route have been studied. CuO addition shows no obvious influence on the phase of the 8SMT-2CST ceramics and all the samples exhibit pure perovskite structure. Appropriate CuO addition can effectively promote sintering and grain growth, and consequently improve the dielectric properties of the ceramics. The sintering temperature of the ceramics decreases by 50C by adding 1.00 wt.%CuO. Superior microwave dielectric properties with a ? r of 29.8, Q f of 85,500 GHz, and ? f of 2.4 ppm/C are obtained for 1.00 wt.%CuO doped 8SMT-2CST ceramics sintered at 1500C, which shows dense and uniform microstructure as well as well-developed grain growth.

  16. 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, E-mail: fpy_2000@163.com; 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.

  17. Silver nanosintering: a lead-free alternative to soldering

    NASA Astrophysics Data System (ADS)

    Maruyama, Minoru; Matsubayashi, Ryo; Iwakuro, Hiroaki; Isoda, Seiji; Komatsu, Teruo

    2008-07-01

    We propose a lead-free silver paste as a replacement for a high-temperature lead-rich solder used for electronics. The pastes tested here contain a small amount of solvent, but primarily consist of silver powder and alkoxide-passivated silver nanoparticles that undergo nanosintering when heated. The pastes were used to connect silicon diode chips to copper bases at 350C in nitrogen ambient without external pressure. The resulting diode packages had electrical and thermal properties about equal to those with lead-solder joints. The mechanical strengths also were comparable to the lead joint. These properties make this nanosilver paste the first viable lead-free alternative to a lead solder.

  18. Fatigue fracture mechanisms of Cu\\/lead-free solders interfaces

    Microsoft Academic Search

    Q. K. Zhang; Q. S. Zhu; Z. F. Zhang

    2010-01-01

    The fatigue fracture behaviors of a series of Cu\\/lead-free solder joints deformed under different directions of loadings were investigated in this study. Observation results showed that fatigue cracks generally initiate around the IMC\\/solder interface when the loading axis is vertical to the interface. For all the solder joints, the interfacial deformations are resulting from strain localization induced by the stain

  19. Lead free soldering electronic interconnect: Current status and future developments

    Microsoft Academic Search

    K. G. Snowdon; C. G. Tanner; J. R. Thompson

    2000-01-01

    There is world-wide concern about the potential ecological impacts of lead-based solders, present in old electronic equipment buried in landfill sites. This paper reports the results of over nine years R and D at Nortel Networks on identification, evaluation and deployment of lead-free solders for printed circuit board assembly. This work has resulted in the production of the world's first

  20. 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.

  1. 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.

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

    SciTech Connect

    Jain, Rajni; Chauhan, Arun Kumar Singh; Gupta, Vinay; Sreenivas, K. [Department of Physics and Astrophysics, University of Delhi, Delhi-110007 (India)

    2005-06-15

    The effect of poling on the structural, dielectric, and piezoelectric properties has been investigated for sol-gel-derived strontium bismuth tantalate (SBT) [Sr{sub 1-x}Bi{sub 2+2x/3}Ta{sub 2}O{sub 9}] ceramics with x=0.0,0.15,0.30,0.45. The dielectric and ferroelectric properties are found to improve with increase in x up to 0.3. Beyond x>0.3 the properties are found to degrade due to the limited solid solubility and the presence of a mixed phase of bismuth tantalate (BiTaO{sub 4}) is detected with x=0.45. Poling treatment reduces the dielectric dispersion and dielectric loss in the frequency range (0.1-100 kHz). The resonance and antiresonance frequencies increase with increase in x (x=0-0.30), and the corresponding minimum impedance decreases. The measured coupling coefficients (k{sub p}) are small (0.0967-0.1) for x=0-0.30, and the electromechanical quality factor (Q{sub m}=915) is a maximum for the Sr{sub 0.7}Bi{sub 2.2}Ta{sub 2}O{sub 9} composition (x=0.30). The estimated piezoelectric charge coefficient (d{sub 31}) and piezoelectric voltage coefficient (g{sub 31}) are 5.2 pC/N and 5.8x10{sup -3} V m/N, respectively. The positive values of d{sub 31} and g{sub 31} and the low dielectric permittivity of SBT yield a high value for the hydrostatic coefficients, despite the low charge coefficient of d{sub 33}=24 pC/N. The maximum values of charge coefficient (d{sub h}=34 pC/N) and voltage coefficient (g{sub h}=39x10{sup -3} V m/N) are obtained for Sr{sub 0.7}Bi{sub 2.2}Ta{sub 2}O{sub 9} composition, and the estimated hydrostatic figure of merit (d{sub h}g{sub h}x10{sup -15}=1215 m{sup 2}/N) is high.

  3. A micromachining process for die-scale pattern transfer in ceramics and its application to bulk piezoelectric actuators

    Microsoft Academic Search

    Tao Li; Yogesh B. Gianchandani

    2006-01-01

    This paper reports on a batch mode planar pattern transfer process for bulk ceramics, glass, and other hard, brittle, nonconductive materials suitable for micromachined transducers and packages. The process is named LEEDUS, as it combines lithography, electroplating, batch mode micro electro-discharge machining (?EDM) and batch mode micro ultrasonic machining (?USM). An electroplating mold is first created on a silicon or

  4. Mechanical constitutive behavior and exceptional blocking force of lead-free BZT-xBCT piezoceramics

    NASA Astrophysics Data System (ADS)

    Brandt, David R. J.; Acosta, Matias; Koruza, Jurij; Webber, Kyle G.

    2014-05-01

    The free strain during unipolar electrical activation and the blocking stress are important figures of merit for actuator applications. The lead-free (1 - x)Ba(Zr0.2Ti0.8)O3-x(Ba0.7Ca0.3)TiO3 (BZT-xBCT) system has been shown to display exceptional unipolar strain at room temperature, making it very attractive as an electroactive material for large displacement, low frequency actuation systems. In this work, the temperature- and composition-dependent blocking stress is measured with the proportional loading method. It was found that BZT-xBCT outperformed Pb(Zr1-xTix)O3 and Bi1/2Na1/2TiO3-based ceramics for electric fields up to 2 kV/mm.

  5. 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.

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

    SciTech Connect

    Schiemer, Jason [Research School of Chemistry, The Australian National University, Canberra, ACT 0200 (Australia)] [Research School of Chemistry, The Australian National University, Canberra, ACT 0200 (Australia); Withers, Ray L., E-mail: withers@rsc.anu.edu.au [Research School of Chemistry, The Australian National University, Canberra, ACT 0200 (Australia); Liu, Yun; Yi, Zhiguo [Research School of Chemistry, The Australian National University, Canberra, ACT 0200 (Australia)] [Research School of Chemistry, The Australian National University, Canberra, ACT 0200 (Australia)

    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.

  7. Relaxor behaviour of low lead and lead free ferroelectric ceramics of the Na 0.5Bi 0.5TiO 3PbTiO 3 and Na 0.5Bi 0.5TiO 3K 0.5Bi 0.5TiO 3 systems

    Microsoft Academic Search

    Jean-Pierre Mercurio

    2001-01-01

    Ceramics with compositions belonging to the Na0.5Bi0.5TiO3PbTiO3 and Na0.5Bi0.5TiO3K0.5Bi0.5TiO3 systems were fabricated by natural sintering of powders prepared by thermal decomposition of adequate precursor solutions. The ferroelectric to paraelectric phase transitions were studied by variable temperature X-ray diffractometry, differential scanning calorimetry and impedance measurement in a wide range of temperature and frequency. In contrast with pure NBT, both the permittivity

  8. 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

  9. New lead-free, Sn-Zn-In solder alloys

    Microsoft Academic Search

    M. McCormack; S. Jin; H. S. Chen; D. A. Machusak

    1994-01-01

    In view of the need for a lead-free, drop-in replacement for the widely used 40Pb-60Sn near-eutectic solder (m.p. ~183C),\\u000a new Sn-Zn-ln based alloys with substantially the same melting point have been developed. It is shown that the alloying additions\\u000a of In to the Sn-Zn binary system result in a suppression of the melting point to 175-188C, and at the same

  10. Studies on lead-free multiferroic magnetoelectric composites

    Microsoft Academic Search

    S. Narendra Babu; K. Srinivas; T. Bhimasankaram

    2009-01-01

    Lead-free multiferroic magnetoelectric composites consisting of ferrimagnetic Ni0.93Co0.02Mn0.05Fe1.95O4 (NMF) and ferroelectric Na0.5Bi0.5TiO3 (NBT) phases were synthesized by the solid-state sintering method. The presence of constituent phases in composites was confirmed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). A systematic study of dc conductivity as a function of temperature (RT ?450C) revealed that the conduction is due to small

  11. Effect of the Addition of B2O3 on the Density, Microstructure, Dielectric, Piezoelectric and Ferroelectric Properties of K0.5Na0.5NbO3 Ceramics

    NASA Astrophysics Data System (ADS)

    Bharathi, P.; Varma, K. B. R.

    2014-02-01

    Boron oxide (B2O3) addition to pre-reacted K0.5Na0.5NbO3 (KNN) powders facilitated swift densification at relatively low sintering temperatures which was believed to be a key to minimize potassium and sodium loss. The base KNN powder was synthesized via solid-state reaction route. The different amounts (0.1-1 wt%) of B2O3 were-added, and ceramics were sintered at different temperatures and durations to optimize the amount of B2O3 needed to obtain KNN pellets with highest possible density and grain size. The 0.1 wt% B2O3-added KNN ceramics sintered at 1,100 C for 1 h exhibited higher density (97 %). Scanning electron microscopy studies confirmed an increase in average grain size with increasing B2O3 content at appropriate temperature of sintering and duration. The B2O3-added KNN ceramics exhibited improved dielectric and piezoelectric properties at room temperature. For instance, 0.1 wt% B2O3-added KNN ceramic exhibited d 33 value of 116 pC/N which is much higher than that of pure KNN ceramics. Interestingly, all the B2O3-added (0.1-1 wt%) KNN ceramics exhibited polarization-electric field ( P vs. E) hysteresis loops at room temperature. The remnant polarization ( P r) and coercive field ( E c) values are dependent on the B2O3 content and crystallite size.

  12. Dielectric and piezoelectric properties of Bi{sub 2}O{sub 3} added (Pb,Ca,Sr)(Ti,Mn,Sb)O{sub 3} ceramics sintered at low temperature

    SciTech Connect

    Kim, Dohyung; Yoo, Juhyun [Department of Electrical Engineering, Semyung University, Jechon, Chungbuk 390-711 (Korea, Republic of); Kim, Insung; Song, Jaesung [Piezoelectric Devices Research Group, KERI, Changwon 641-12 (Korea, Republic of)

    2009-03-15

    In this study, in order to develop low temperature sintering ceramics for a thickness mode multilayer piezoelectric transformer, (Pb,Ca,Sr)(Ti,Mn,Sb)O{sub 3} ceramics were fabricated using Na{sub 2}CO{sub 3}, Li{sub 2}CO{sub 3}, MnO{sub 2}, and Bi{sub 2}O{sub 3} as sintering aids at 870, 900, and 930 deg. C. Their respective dielectric and piezoelectric properties were investigated according to the amount of Bi{sub 2}O{sub 3} addition. At the sintering temperature of 900 deg. C, the optimum value was shown for the density of 6.94 g/cm{sup 3}, thickness vibration mode electromechanical coupling factor (henceforth, k{sub t}) of 0.497, thickness vibration mode mechanical quality factor (henceforth, Q{sub mt}) of 3162, and dielectric constant (henceforth, {epsilon}{sub r}) of 209 for thickness mode multilayer piezoelectric transformer application.

  13. High T{sub c} lead-free BaTiO{sub 3}-(Bi{sub 1/2}Na{sub 1/2})TiO{sub 3} positive temperature coefficient of resistivity ceramics with electrically heterogeneous structure

    SciTech Connect

    Xiang Pinghua; Takeda, Hiroaki; Shiosaki, Tadashi [Graduate School of Materials Science, Nara Institute of Science and Technology, 8916-5 Takayama-cho, Ikoma, Nara 630-0192 (Japan)

    2007-10-15

    A distinct positive temperature coefficient of resistivity effect has been observed in BaTiO{sub 3}-(Bi{sub 1/2}Na{sub 1/2})TiO{sub 3} (BT-BNT) ceramics sintered in a N{sub 2} flow with low O{sub 2} concentration. With the addition of BNT, the samples exhibit resistivity jumps of {approx}10{sup 3}-10{sup 5} starting at {approx}190-210 deg. C. X-ray diffraction results indicate that the BNT phase and BT phase formed a solid solution during sintering. An electrically heterogeneous structure, consisting of the grain interiors, outer grain shells, and grain boundaries, is revealed by the complex impedance analyses. The observed dc resistivity jump is attributed to the rapid resistivity rise in both grain boundaries and grain shells.

  14. 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.

  15. Piezoelectric response of charged non-180 domain walls in ferroelectric Zhanfang Li, Hao Wu, and Wenwu Cao

    E-print Network

    Cao, Wenwu

    Piezoelectric response of charged non-180 domain walls in ferroelectric ceramics Zhanfang Li, Hao://jap.aip.org/authors #12;Piezoelectric response of charged non-180 domain walls in ferroelectric ceramics Zhanfang Li,1 Hao walls in ferroelectric ceramic, it can enhance the extrinsic contribution to the piezoelectric

  16. Dielectric and piezoelectric properties of PbFe1/2Nb1/2O3-PbTiO3 ceramics from the morphotropic phase boundary compositional range.

    PubMed

    Sitalo, Eugene I; Raevski, Igor P; Lutokhin, Alexander G; Blazhevich, Alexei V; Kubrin, Stanislav P; Raevskaya, Svetlana I; Zakharov, Yuriy N; Malitskaya, Maria A; Titov, Victor V; Zakharchenko, Irina N

    2011-09-01

    Dielectric, X-ray, and piezoelectric studies of highly-resistive Li-doped (1-x)PbFe(1/2)Nb(1/2)O(3)-(x)PbTiO(3) (PFN-xPT) ceramics from the 0 ? x ? 0.2 range fabricated by solid-state synthesis and usual sintering have been carried out. Distinct anomalies of dielectric and piezoelectric parameters, corresponding to the transition between rhombohedral (monoclinic) and tetragonal ferroelectric phases, have been observed in pure PFN and PFN-xPT compositions with PbTiO(3) content up to 8 mol.%. The x,T-phase diagram of the PFN-xPT solid solution system has been constructed using these data. PMID:21937325

  17. Giant energy density in [001]-textured Pb(Mg1/3Nb2/3)O3-PbZrO3-PbTiO3 piezoelectric ceramics

    NASA Astrophysics Data System (ADS)

    Yan, Yongke; Cho, Kyung-Hoon; Maurya, Deepam; Kumar, Amit; Kalinin, Sergei; 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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-11-01

    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.

  19. Lead-free technologies for electronic equipment assembly

    NASA Astrophysics Data System (ADS)

    Kisiel, Ryszard

    2003-10-01

    The electronic industry is now going through a difficult period. The companies must cut costs, regroup and innovate. Environmentally friendly production from cradle-to-grave can be an essential element of future manufacturing trends. Recognizing leaf-free technology implementation it is necessary to consider the following elements: solder, printed circuit board and component finish or assembly technology. In the paper, the [hysical properties of chosen Pb-free solders were presented. There were analyzed the advantages and disadvantages of two PCB assembly methods: lead free soldering and gluing by condictive adhesive. The comparison of electrical and mechanical properties of joints made by Pb-free solders and two types of conductive adhesives were presented too. It was concluded that the exploitation parameters of joints made by Pb-free solders are proper for PCB assembly. Conductive adhesives may replace solders in these applications were the low value of joint resistance is not critical.

  20. 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.

  1. Variation of Piezoelectric properties and mechanisms across the relaxor-like/Ferroelectric continuum in BiFeO3- (K0.5Bi0.5)TiO3-PbTiO3 ceramics.

    PubMed

    Bennett, James; Shrout, Thomas R; Zhang, Shujun; Owston, Heather E; Stevenson, Tim J; Esat, Faye; Bell, Andrew J; Comyn, T P

    2015-01-01

    1- x - y)BiFeO3-x(K0.5Bi0.5)TiO3-yPbTiO3 (BFKBT- PT) piezoelectric ceramics were investigated across the compositional space and contrasted against the xBiFeO3- (1-x)(K0.5Bi0.5)TiO3 (BF-KBT) system, whereby a range of relaxor-like/ferroelectric behavior was observed. Structural and piezoelectric properties were closely related to the PbTiO3 concentration; below a critical concentration, relaxor-like behavior was identified. The mechanisms governing the piezoelectric behavior were investigated with structural, electrical, and imaging techniques. X-ray diffraction established that longrange non-centrosymmetric crystallographic order was evident above a critical PbTiO3 concentration, y > 0.1125. Commensurate with the structural analysis, electric-field-induced strain responses showed electrostrictive behavior in the PbTiO3-reduced compositions, with increased piezoelectric switching in PbTiO3-rich compositions. Positive-up-negative-down (PUND) analysis was used to confirm electric-field-induced polarization measurements, elucidating that the addition of PbTiO3 increased the switchable polarization and ferroelectric ordering. Piezoresponse force microscopy (PFM) of the BF-KBT-PT system exhibited typical domain patterns above a critical PbTiO3 threshold, with no ferroelectric domains observed in the BF-KBT system in the pseudocubic region. Doping of BiFeO3-PbTiO3 has been unsuccessful in the search for hightemperature materials that offer satisfactory piezoelectric properties; however, this system demonstrates that the partial substitution of alternative end-members can be an effective method. The partial substitution of PbTiO3 into BF-KBT enables long-range non-centrosymmetric crystallographic order, resulting in increased polar order and TC, compared with the pseudocubic region. The search for novel high-temperature piezoelectric ceramics can therefore exploit the accommodating nature of the perovskite family, which allows significant variance in chemical and physical characters in the exploration of new solid-solutions. PMID:25585388

  2. Continuous cross-over from ferroelectric to relaxor state and piezoelectric properties of BaTiO{sub 3}-BaZrO{sub 3}-CaTiO{sub 3} single crystals

    SciTech Connect

    Benabdallah, F.; Veber, P., E-mail: veber@icmcb-bordeaux.cnrs.fr; Prakasam, M.; Viraphong, O.; Maglione, M. [CNRS, ICMCB, UPR 9048, F-33600 Pessac (France); Universit Bordeaux, ICMCB, UPR 9048, F-33600 Pessac (France); Shimamura, K. [National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan)

    2014-04-14

    Optimal properties like piezoelectricity can be found in polarizable materials for which the structure changes sharply under small composition variations in the vicinity of their morphotropic phase boundary or the triple point in their isobaric temperature-composition phase diagram. In the latter, lead-free (Ba{sub 0.850}Ca{sub 0.150})(Ti{sub 0.900}Zr{sub 0.100})O{sub 3} ceramics exhibit outstanding piezoelectric coefficients. For the first time, we report the growth of piezoelectric lead-free single crystals in the BaTiO{sub 3}-BaZrO{sub 3}-CaTiO{sub 3} pseudo-ternary system. The stoichiometry control in the CaO-BaO-TiO{sub 2}-ZrO{sub 2} solid solution led to single crystals with various compositions ranging from (Ba{sub 0.857}Ca{sub 0.143})(Ti{sub 0.928}Zr{sub 0.072})O{sub 3} to (Ba{sub 0.953}Ca{sub 0.047})(Ti{sub 0.427}Zr{sub 0.573})O{sub 3}. We evidenced a continuous cross-over from a ferroelectric state at high titanium content to a relaxor one on increasing the zirconium content. Such a property tuning is rather seldom observed in lead-free ferroelectrics and confirms what was already reported for ceramics. Single crystal with (Ba{sub 0.838}Ca{sub 0.162})(Ti{sub 0.854}Zr{sub 0.146})O{sub 3} composition, which has been grown and oriented along [001] crystallographic direction, displayed electromechanical coefficients d{sub 31} and k{sub 31} of 93 pC.N{sup ?1} and 0.18, respectively, near the room temperature (T?=?305?K)

  3. A comparison between several approaches of piezoelectric energy harvesting

    Microsoft Academic Search

    E. Lefeuvre; A. Badel; A. Benayad; L. Lebrun; C. Richard; D. Guyomar

    2005-01-01

    This paper compares the performances of vibration-powered electrical generators using a piezoelectric ceramic and a piezoelectric single crystal associated to several power conditioning interfaces. A new approach of the piezoelectric power conversion based on a non linear voltage processing is presented, leading to three novel high-performance techniques. Theoretical predictions and experimental results show that the novel techniques may increase the

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

    PubMed

    Zhang, Jitao; Li, Ping; Wen, Yumei; He, Wei; Yang, Aichao; Lu, Caijiang

    2014-03-01

    An enhancement for magnetoelectric (ME) effects is studied in a three-phase ME architecture consisting of two magnetostrictive Terfenol-D (Tb(0.3)Dy(0.7)Fe(1.92)) plates, a piezoelectric PZT (Pb(Zr,Ti)O3) plate, and a pair of shape-optimized FeCuNbSiB nanocrystalline alloys. By modifying the conventional shape of the magnetic flux concentrator, the shape-optimized flux concentrator has an improved effective permeability (?(eff)) due to the shape-induced demagnetizing effect at its end surface. The flux concentrator concentrates and amplifies the external magnetic flux into Terfenol-D plate by means of changing its internal flux concentrating manner. Consequently, more flux lines can be uniformly concentrated into Terfenol-D plates. The effective piezomagnetic coefficients (d(33m)) of Terfenol-D plate and the ME voltage coefficients (?(ME)) can be further improved under a lower magnetic bias field. The dynamic magneto-elastic properties and the effective magnetic induction of Terfenol-D are taken into account to derive the enhanced effective ME voltage coefficients (?(ME,eff)), the consistency of experimental results and theoretical analyses verifies this enhancement. The experimental results demonstrate that the maximum d(33m) in our proposed architecture achieves 22.48?nm/A under a bias of 114 Oe. The maximum ?(ME) in the bias magnetic range 0-900 Oe reaches 84.73 mV/Oe under the low frequency of 1 kHz, and 2.996 V/Oe under the resonance frequency of 102.3 kHz, respectively. It exhibits a 1.43 times larger piezomagnetic coefficient and a 1.87 times higher ME voltage coefficient under a smaller magnetic bias of 82 Oe than those of a conventional Terfenol-D/PZT/Terfenol-D composite. These shape-induced magnetoelectric behaviors provide the possibility of using this ME architecture in ultra-sensitive magnetic sensors. PMID:24689597

  5. Viscoelectroelastic behavior of heterogeneous piezoelectric solids JiangYu Lia)

    E-print Network

    Li, Jiangyu

    -type relaxations in ferroelectric single crys- tals that have been attributed to ferroelectric domain wall motion,8 and relaxation in polycrystalline ceramics due to motion of 90 domain walls.912 Complex piezoelectric con been observed in bone,14 and in piezoelectric ceramic/polymer matrix composites.1517 In bone

  6. PLZT-based photovoltaic Piezoelectric Transformer with light feedback

    Microsoft Academic Search

    L. Kozielski; M. Adamczyk; J. Erhart

    2011-01-01

    Piezoelectric Transformer (PT) converts an electrical AC input voltage into ultrasonic vibrations and reconverts back to an output as AC voltage. Hard lead zirconate titanate (PZT) ceramics is typically used for fabrications of such devices. In case of lanthaniun ion La3+ addition in PZT solid solution we can achieve piezoelectric ceramics with good transparency exhibiting both optical Pockels and Kerr

  7. High-Temperature Piezoelectrics with Large Piezoelectric Coefficients

    NASA Astrophysics Data System (ADS)

    Shinekumar, K.; Dutta, Soma

    2015-02-01

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

  8. Structure, Ferroelectric and Photoluminescence Properties of Eu-Doped CaBi4Ti4O15 Multifunctional Ceramics

    NASA Astrophysics Data System (ADS)

    Wu, Xiaochun; Xiao, Ping; Guo, Yongquan; Zheng, Qiaoji; Lin, Dunmin

    2015-04-01

    Lead-free multifunctional ceramics of CaBi4-x Eu x Ti4O15 were prepared by a traditional solid state method, and the effects of Eu doping on structure, ferroelectric, piezoelectric and photoluminescence properties of the ceramics were investigated. All the ceramics possessed typical bismuth layer structure with m = 4, belonging to orthorhombic symmetry, and no secondary phase was detected. The plate-like grains were observed in all the ceramics, and the grain growth was slightly inhibited after the addition of Eu. Saturated polarization hysteresis loops were observed for all the ceramics, and the remanent polarization P r decreased with Eu doping. The Eu-doped ceramics had a sharp excitation band centered at 465 nm due to the f-f transition from the 7F0 ground state to the 5D2 excited state of Eu3+. Under the excitation by 465 nm light, the main emission peaks located at 595 nm and 616 nm were obtained, which corresponds to the transition of 5D0-7F1, 5D0-7F2 levels in Eu3+, respectively. Our study shows that CaBi4Ti4O15 ceramics may be a promising multifunctional material for potential applications in optical-electro integration devices.

  9. Local and Global Properties of a Lead-Free Solder

    NASA Astrophysics Data System (ADS)

    Ma, Z.; Chalon, F.; Leroy, R.; Ranganathan, N.; Beake, B. D.

    2013-07-01

    Elastic and viscous properties including Young's modulus, hardness, creep rate sensitivity, and fatigue resistance of Sn-1.2Ag-0.5Cu-0.05Ni lead-free solder have been investigated. The properties of bulk specimens and in situ solder balls are compared. Experiments show good correlations of Young's modulus and creep rate sensitivity between conventional measurements and nanoindentation results on bulk specimens. Further mechanical properties of the beach-ball microstructure in solder balls are characterized by nanoindentation. The load-partial unload technique has been used to determine the variation in mechanical properties with increasing depth of penetration into the intermetallic inclusions in the in situ solder. The fatigue resistances of the bulk specimens and solder balls are compared by using the novel nanoimpact method. In comparison with bulk specimens, it is found that in situ solder has higher Young's modulus, lower creep strain rate sensitivity, and better fatigue resistance. The effects of soldering and the scale differences strongly affect the mechanical and fatigue properties of in situ solder.

  10. 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 [Department of Materials Science and Engineering, Korea University, 1-5 Ka, Anam-Dong, Sungbud-Ku, Seoul 136-701 (Korea, Republic of); International Center for Actuators and Transducers, Materials Research Institute, Pennsylvania State University, University Park, Pennsylvania 16802 (United States); Korea Electronics Technology Institute, 68 Yatap-dong, Bundang-gu, Soeongnam-si, Gyeonggi-do 463-816 (Korea, Republic of); New Materials Evaluation Center, Korea Research Institute of Standards and Science, Daeduk Science Town, Taejon 305-600 (Korea, Republic of)

    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.

  11. 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.

  12. Semiconductor/relaxor 0-3 type composites without thermal depolarization in Bi?.?Na?.?TiO?-based lead-free piezoceramics.

    PubMed

    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

    2015-01-01

    Commercial lead-based piezoelectric materials raised worldwide environmental concerns in the past decade. Bi?.?Na?.?TiO?-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 Bi?.?Na?.?TiO?-based 0-3-type composites. This is achieved by introducing semiconducting ZnO particles into the relaxor ferroelectric 0.94Bi?.?Na?.?TiO?-0.06BaTiO? 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 Bi?.?Na?.?TiO?-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. PMID:25790446

  13. 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.

  14. 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

  15. Piezoelectric valve

    DOEpatents

    Petrenko, Serhiy Fedorovich

    2013-01-15

    A motorized valve has a housing having an inlet and an outlet to be connected to a pipeline, a saddle connected with the housing, a turn plug having a rod, the turn plug cooperating with the saddle, and a drive for turning the valve body and formed as a piezoelectric drive, the piezoelectric drive including a piezoelectric generator of radially directed standing acoustic waves, which is connected with the housing and is connectable with a pulse current source, and a rotor operatively connected with the piezoelectric generator and kinematically connected with the rod of the turn plug so as to turn the turn plug when the rotor is actuated by the piezoelectric generator.

  16. 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 ...

  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. Design with Advanced Ceramics Course Outline

    E-print Network

    New South Wales, University of

    11th March Ferroelectric Ceramics and Their Applications 3 17th March 18th March PiezoelectricMATS4002 Design with Advanced Ceramics Course Outline Session 1, 2014 School of Materials Science Ceramics 4 24th March 25th March Electro-optic Ceramics and Fibre-Optic Sensors 5 31st March 1st April

  19. Dielectric and piezoelectric properties of <001> fiber-textured 0.675Pb(Mg1/3Nb2/3)O3-0.325PbTiO3 ceramics

    NASA Astrophysics Data System (ADS)

    Sabolsky, Edward M.; Trolier-McKinstry, Susan; Messing, Gary L.

    2003-04-01

    The 0.675Pb(Mg1/3Nb2/3)O3-0.325PbTiO3 (PMN-32.5PT) ceramic composition (with 1 wt. % excess PbO) was fiber textured in the <001> direction by the templated grain growth process using 5 vol % oriented {001}-BaTiO3 platelet crystals as the templates. The templated ceramics annealed at 1150 C for 5 h attained texture fractions as high as 0.9. The fiber-textured samples showed an increase in the piezoelectric, electromechanical coupling, and compliance coefficients when poled and measured in the <001>-textured direction. The low drive field (<5 kV/cm) d33 coefficients in the <001>, measured directly from unipolar strain-field measurements, were 1150 pC/N. This d33 coefficient is 1.2-1.5 times greater than randomly oriented samples. The poled ?max and ?rt for a 0.9-textured PMN-32.5PT ceramic were 21 500 and 2450, respectively. Factors limiting further property improvements are discussed.

  20. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2015-02-01

    It is still a challenging problem to obtain technologically useful materials displaying strong magnetoelectric coupling at room temperature. In the search for new effects and materials to achieve this kind of coupling, a nonlinear magnetoelectric effect was proposed in the magnetically disordered relaxor ferroelectric materials. In this context, the aluminum iron oxide (AlFeO3), a room temperature ferroelectric relaxor and magnetic spin glass compound, emerges as an attractive lead-free magnetoelectric material along with nonlinear magnetoelectric effects. In this work, static, dynamic, and temperature dependent ferroic and magnetoelectric properties in lead-free AlFeO3 and 2 at. % Nb-doped AlFeO3 multiferroic magnetoelectric compositions are studied. Pyroelectric and magnetic measurements show changes in ferroelectric and magnetic states close to each other (200 K). The magnetoelectric coefficient behavior as a function of Hbias suggests a room temperature nonlinear magnetoelectric coupling in both single-phase and Nb-doped AlFeO3-based ceramic compositions.

  2. 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.

  3. 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

  4. Analysis of lead free tin-silver-copper and tin-lead solder wetting reactions

    Microsoft Academic Search

    Scott J. Anson

    2007-01-01

    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

  5. Reliability and microstructure of lead-free solder die attach interface in silicon power devices

    Microsoft Academic Search

    D. Huff; D. Katsis; K. Stinson-Bagby; T. Thacker; G.-Q. Lu; J. D. van Wyk

    2004-01-01

    The use of lead in electronic consumer products is being phased out in exchange for lead-free alternatives. Understanding the physics of failure mechanisms within lead-free solder alloys will facilitate the replacement of lead bearing alloys for silicon device bonding in power semiconductor modules. Japan's legislation for reduction in lead bearing solders is presently in place while European legislation is slated

  6. Effects of Fe2O3 addition on the piezoelectric and the dielectric properties of 0.99Pb(Zr0.53Ti0.47)O3-0.01Bi(Y1- x Fe x )O3 ceramics for energy-harvesting devices

    NASA Astrophysics Data System (ADS)

    Mahmud, Iqbal; Ur, Soon-Chul; Yoon, Man-Soon

    2014-07-01

    The 0.99Pb(Zr0.53Ti0.47)O3-0.01Bi(Y1- x Fe x )O3 [PZT-BYF(x)] (x = 0.0 - 0.6) piezoelectric ceramics have been synthesized by using a modified conventional solid-state method. Initially, the perovskite Pb(Zr0.53Ti0.47)O3 (PZT) and the cubic-phase Bi(Y1- x Fe x )O3 [BYF(x)] were presynthesized and mixed to prepare PZT-BYF(x) ceramic composites. The effects of BYF(x) addition on the phase formation, microstructure, and piezoelectric/dielectric properties were measured as functions of sintering temperature. In addition to these measurements, the piezoelectric voltage constant ( g 33) and the piezoelectric transduction coefficient ( d 33 g 33) were measured in order to evaluate the essential criteria for an energy-harvesting material. For all the specimens, X-ray diffraction analyses showed a complete solid solution with co-existing tetragonal and rhombohedral perovskite phases. All the ceramics exhibited denser and finer microstructures, which produced a high relative density of ? 98%. Scanning electron microscopy (SEM) observations revealed that BYF(x) addition enhanced the sintering density through the formation of a liquid phase. The doping with BYF(x) in the PZT system was found to be effective for maintaining a high Curie temperature of around 377-390 C. With increasing content of Fe2O3 in the BYF(x) system, the piezoelectric and the dielectric properties were significantly improved. At a sintering temperature of 1170 C, the piezoelectric and the dielectric properties of PZT-BYF(x) ceramics showed desirable values; this resulted in a significantly higher transduction coefficient. The compositions of PZTBYF(0.1), PZT-BYF(0.2), and PZT-BYF(0.3) showed a considerably lower ? 33 T value, but higher d 33 and k p values. Therefore, within the concentration limit of x = 0.1 to 0.3 moles of Fe2O3, the g 33 and the d 33 g 33 values were improved significantly ( g 33 > 53 10-3 Vm/N and d 33 g 33 > 20000 m2/N). The maximum transduction coefficient of 20167 10-15 m2/N was obtained from the composition of PZT-BYF(0.3). The high values of g 33 and d 33 g 33 make these piezoelectric ceramics potential candidates for applications in energy-harvesting devices.

  7. Piezoelectricity Demo

    NSDL National Science Digital Library

    This lesson plan from the Oregon Museum of Science and Industry explores the history of piezoelectricity, with hands-on examples of how it??s used, models of why it happens, and how it is applied in nanotechnology. Pressing on the piezoelectric buzzer in the background causes a current to flow and the neon bulb in the foreground to glow.

  8. 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

  9. Polar glass ceramics

    Microsoft Academic Search

    A. Halliyal; A. S. Bhalla; R. E. Newnham; L. E. Cross

    1981-01-01

    Pyroelectric-piezoelecric glass ceramics of polar materials like Li2Si2O5, Ba2TiGe2O8, Ba2TiSi2O8, and Various compositions in the systems Li2O-B2O3, Li2O-SiO2-ZnO, Li2O-SiO2-B2O3 have been prepared by oriented recrystallization of the glasses under a strong temperature gradient, providing a simple inexpensive process for preparing piezoelectric and pyroelectric materials. High pyroelectric responses were observed in these glass-ceramics. Values of piezoelectric d33 coefficients, frequency constants, electromechanical

  10. Wettability of electroless Ni in the under bump metallurgy with lead free solder

    Microsoft Academic Search

    Bi-Lian Young; Jenq-Gong Duh; Bi-Shiou Chiou

    2001-01-01

    This study investigates the wettability of several lead-free solders, including Sn, Sn?Ag, and Sn?Bi, on electroless Ni (EN)\\u000a with various phosphorus content. The role of phosphorus on solder wettability is studied. Microstructure evolution in the\\u000a lead-free solder\\/EN joint is investigated with the aid of electron probe microanalyzer (EPMA) to relate metallurgical reactions\\u000a between the solder and the EN. The SN

  11. A General Methodology to Predict Fatigue Life in Lead-Free Solder Alloy Interconnects

    Microsoft Academic Search

    David M. Pierce; Sheri D. Sheppard; Paul T. Vianco

    2009-01-01

    The ubiquitous eutectic tin-lead (Sn-Pb) solder alloys are soon to be replaced with lead-free alternatives. In light of this transition, new computational tools for predicting the fatigue life of lead-free solders are required. A fatigue life prediction methodology was developed, based upon stress-strain, creep and isothermal fatigue data; the later generated using a double lap-shear (DLS) test assembly. The proposed

  12. Life-time Tests of Lead-free Solder Joints on Flexible Printed Circuits

    Microsoft Academic Search

    Zsolt Illyefalvi-Vitez; Bailint Balogh; G. Farmer; A. Girulska; D. Kirkpatrick

    2007-01-01

    The electronics industry is in the transition to lead-free technology, and it is very important for all industrial performers, including small and medium size enterprises (SMEs), to keep pace with this process. FlexNoLead (Flexible Circuits Processing, Performance and Reliability using Lead-Free Soldering Process, EC Contract: COOP-CT-2004-513163), a European Commission sponsored cooperative research project is aimed at assisting SMEs in the

  13. Processing, properties, and reliability of electroplated lead-free solder bumps

    Microsoft Academic Search

    R. Kiumi; J. Yoshioka; F. Kuriyama; N. Saito; M. Shimoyama

    2002-01-01

    Eutectic tin-silver (Sn-Ag), tin-copper (Sn-Cu), and tin-silver-copper (Sn-Ag-Cu) solder alloys are potential lead-free materials for low-temperature processing of solder bumps on wafers. But, before they can be adopted to replace the existing lead-free materials, processes have to be developed to provide controls over composition, height and shape uniformity, and defect formation, such as micro-voids, which are detrimental to bump reliability.

  14. Reduction of lead free solder aging effects using doped SAC alloys

    Microsoft Academic Search

    Zijie Cai; Yifei Zhang; Jeffrey C. Suhling; Pradeep Lall; R. Wayne Johnson; Michael J. Bozack

    2010-01-01

    The microstructure, mechanical response, and failure behavior of lead free solder joints in electronic assemblies are constantly evolving when exposed to isothermal aging and\\/or thermal cycling environments. In our prior work on aging effects, we have demonstrated that large degradations occur in the material properties (stiffness and strength) and creep behavior of Sn-Ag-Cu (SAC) lead free solders during aging. These

  15. Contact resistance and fretting corrosion of lead-free alloy coated electrical contacts

    Microsoft Academic Search

    Ji Wu; Michael G. Pecht

    2004-01-01

    As lead-free solders replace tin-lead solders in soldering, it is also expected that lead-free solder alloys will be used as contact finish materials for electrical contacts. In this study, the contact resistance and fretting corrosion of tin-silver-copper and tin-copper coatings were investigated and compared with tin-lead eutectic coating. The contact resistance before after different aging conditions, including mixed flowing gas,

  16. Contact resistance and fretting corrosion of lead-free alloy coated electrical contacts

    Microsoft Academic Search

    Ji Wu; Michael G. Pecht

    2006-01-01

    As lead-free solders replace tin-lead solders in soldering, it is also expected that lead-free solder alloys will be used as contact finish materials for electrical contacts. In this study, the contact resistance and fretting corrosion of tin-silver-copper and tin-copper coatings were investigated and compared with tin-lead eutectic coating. The contact resistance before and after different aging conditions, including mixed flowing

  17. Flip-Chip Interconnection Using Anisotropic Conductive Adhesive with Lead Free Nano-Solder Particles

    Microsoft Academic Search

    Suresh Chand Verma; Wanbing Guan; Cristina Andersson; Yulai Gao; Qijie Zhai; J. Liu

    2006-01-01

    The flip-chip interconnections obtained using anisotropic conductive adhesives (ACA) containing nanoparticles of Sn-4.0Ag-0.5Cu and Sn-0.4Co-0.7Cu (wt% composition) lead free solder alloys as fillers were studied in order to make use of the nanosize effect in flip-chip interconnection applications. The ACAs were formulated using epoxy resin, curing agent, coupling agent and lead free solder nanoparticles. The filler content used in this

  18. Developing a lead-free solder alloy Sn-Bi-Ag-Cu by mechanical alloying

    Microsoft Academic Search

    C. M. L. Wu; M. L. Huang; J. K. L. Lai; Y. C. Chan

    2000-01-01

    A new lead free alloy, Sn-6Bi-2Ag-0.5Cu, has been developed by mechanical alloying and has great potential as a lead-free solder system. Initial trials on the manufacture of solder joints with this alloy revealed that a high quality bond with copper could be formed. Its melting range of 193.87C to 209.88C is slightly higher than that of eutectic tin-lead solder. Examination

  19. Reliability of printed circuit boards containing lead-free solder in aggressive environments

    Microsoft Academic Search

    M. Moshrefi-TorbatiJ; J. Swingler

    2011-01-01

    Lead-free solders were never an industry choice until government legislation, their wide spread use is still in its infancy\\u000a due to long term reliability issues. A specific SAC (Tin-Silver-Copper) family of solder alloys has emerged as the favourite\\u000a to offer technical advantages as well as meeting those legislative requirements. This paper investigates accelerated life\\u000a behaviour of lead-free solder joints and

  20. STRENGTH OF LEAD-FREE BGA SPHERES IN HIGH SPEED LOADING

    Microsoft Academic Search

    Keith Sweatman; Shoichi Suenaga; Tetsuro Nishimura

    Concern about the failure of lead-free BGA packages when portable devices such as cell phones are accidentally dropped and a general concern about the resistance of these packages under shock loading has prompted an interest in the impact strength of the soldered BGA connection. This paper reports the results of the measurement of the impact strength of lead-free 0.50.01mm diameter

  1. Effect of Interfacial IMCs Proportion on the Reliability of Miniature Lead-Free Solder Joint

    Microsoft Academic Search

    Fengshun Wu; Mingmin He; Yiping Wu; Bing An; Weigang Zhang

    2006-01-01

    The effect of interfacial IMCs (intermetallic compounds) proportion on the reliability of miniature lead-free solder joint was studied. The miniature lead free solder joint was formed with Sn-3.5Ag-0.5Cu or Sn-3.5Ag solder alloys and two copper bars that the ends were plated with Ni and Au. Several sizes of micro-joints were gotten to measure the effect of IMCs proportion. Optical microscope

  2. Lead-free solutions for high and low temperature solder interconnects

    Microsoft Academic Search

    Anthony R Muza

    2009-01-01

    Three distinct approaches were investigated in the development of new high and low temperature lead-free solders. These solutions include using the thermodynamic size effect to reduce melting temperature of current lead-free solders, creating a solderless interconnect through core-shell copper-silver particles, and designing of a partially molten Bi-Ag alloy for high temperature applications.^ Suppressed melting temperatures were observed at temperatures up

  3. The Reliability Research of Lead-Free Solder Joint of Flip-Chip

    Microsoft Academic Search

    Yan De-jin; Zhou De-jian; Huang Chun-yue; Wu Zhao-hua; Zhou xiang

    2006-01-01

    Based on the minimum potential energy theorem and the theory of solder joint shape, 3D (three-dimensional) predicting model of flip-chip lead-free solder joints shape are established. According to different technologic parameters, the 3D solder joint shape is predicted. The nonlinear finite element analyses of the lead-free solder joint is performed by ANSYS under thermal cycles and the stress\\/strain distributions within

  4. Piezoelectric Energy Harvester for Batteryless Switch Devices

    NASA Astrophysics Data System (ADS)

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

    2013-10-01

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

  5. Stresa, Italy, 26-28 April 2006 OPTIMIZATION OF PIEZOELECTRIC ELECTRICAL GENERATORS

    E-print Network

    Boyer, Edmond

    harvesting using piezoelectric materials have been developed over the past few years. OptimizationStresa, Italy, 26-28 April 2006 OPTIMIZATION OF PIEZOELECTRIC ELECTRICAL GENERATORS POWERED generators using PZT piezoelectric ceramic associated to two different power conditioning circuits. A new

  6. Piezoelectric piggy-back microactuator for hard disk drive

    Microsoft Academic Search

    Yoshikazu Soeno; Sliinji Ichikawa; Takamitsu Tsuna; Yoshikazu Sato; Isamu Sato

    1999-01-01

    A new piezoelectric piggy-back microactuator for high density hard disk drives was designed and fabricated to achieve more accurate positioning of the magnetic head and increasing servo bandwidth. The microactuator is made of stiff piezoelectric ceramic material to actuate the slider on which the head-element is formed. It is designed to amplify the actuating displacement. The basic mechanical performance of

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

    NASA Astrophysics Data System (ADS)

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

    2009-12-01

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

  8. Facile Synthesis of Lead-Free Piezoelectric Sodium Niobate (NaNbO3) Powders via the Solution Combustion Method

    Microsoft Academic Search

    Nopsiri Chaiyo; Anucha Ruangphanit; Banjong Boonchom; Naratip Vittayakorn

    2011-01-01

    Nanocrystalline perovskite sodium niobate, NaNbO3 (NN), was prepared by means of the glycine-nitrate combustion process (GNP). This was achieved by using sodium nitrate and niobium pentoxide as starting materials. The X-ray diffraction technique (XRD) was used to investigate the phase formation and purity of synthesized powder. The morphology of the powder obtained was characterized using a scanning electron microscope (SEM).

  9. Enhanced bipolar fatigue resistance in CaZrO3-modified (K,Na)NbO3 lead-free piezoceramics

    NASA Astrophysics Data System (ADS)

    Yao, Fang-Zhou; Patterson, Eric A.; Wang, Ke; Jo, Wook; Rdel, Jrgen; Li, Jing-Feng

    2014-06-01

    The bipolar fatigue behavior of (K,Na)NbO3 (KNN)-based lead-free piezoceramics was investigated. A comparative analysis demonstrated that CaZrO3-modified KNN ceramics exhibited highly enhanced bipolar fatigue resistance due to the reduced lattice distortion (c/a ratio) and coexistence of orthorhombic and tetragonal phases. The hypothesis was verified by systematical studies of cycle-dependent large and small signal parameters and micro-morphologies. It was identified that mechanical stress induced microstructure damage beneath the electrodes renders the KNN ceramics to be vulnerable to bipolar cycling; while the mild fatigue behavior for CaZrO3-modified ones mainly originates from a thermally reversible domain wall pinning.

  10. 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...

  11. Generation of Tin(II) Oxide Crystals on Lead-Free Solder Joints in Deionized Water

    NASA Astrophysics Data System (ADS)

    Chang, Hong; Chen, Hongtao; Li, Mingyu; Wang, Ling; Fu, Yonggao

    2009-10-01

    The effect of the anode and cathode on the electrochemical corrosion behavior of lead-free Sn-Ag-Cu and Sn-Ag-Cu-Bi solder joints in deionized water was investigated. Corrosion studies indicate that SnO crystals were generated on the surfaces of all lead-free solder joints. The constituents of the lead-free solder alloys, such as Ag, Cu, and Bi, did not affect the corrosion reaction significantly. In contrast to lead-free solders, PbO x was formed on the surface of the traditional 63Sn-37Pb solder joint in deionized water. A cathode, such as Au or Cu, was necessary for the electrochemical corrosion reaction of solders to occur. The corrosion reaction rate decreased with reduction of the cathode area. The formation mechanism of SnO crystals was essentially a galvanic cell reaction. The anodic reaction of Sn in the lead-free solder joints occurred through solvation by water molecules to form hydrated cations. In the cathodic reaction, oxygen dissolved in the deionized water captures electrons and is deoxidized to hydroxyl at the Au or Cu cathode. By diffusion, the anodic reaction product Sn2+ and the cathodic reaction product OH- meet to form Sn(OH)2, some of which can dehydrate to form more stable SnO xH2O crystals on the surface of the solder joints. In addition, thermodynamic analysis confirms that the Sn corrosion reaction could occur spontaneously.

  12. High temperature, high power piezoelectric composite transducers.

    PubMed

    Lee, Hyeong Jae; Zhang, Shujun; Bar-Cohen, Yoseph; Sherrit, Stewart

    2014-01-01

    Piezoelectric composites are a class of functional materials consisting of piezoelectric active materials and non-piezoelectric passive polymers, mechanically attached together to form different connectivities. These composites have several advantages compared to conventional piezoelectric ceramics and polymers, including improved electromechanical properties, mechanical flexibility and the ability to tailor properties by using several different connectivity patterns. These advantages have led to the improvement of overall transducer performance, such as transducer sensitivity and bandwidth, resulting in rapid implementation of piezoelectric composites in medical imaging ultrasounds and other acoustic transducers. Recently, new piezoelectric composite transducers have been developed with optimized composite components that have improved thermal stability and mechanical quality factors, making them promising candidates for high temperature, high power transducer applications, such as therapeutic ultrasound, high power ultrasonic wirebonding, high temperature non-destructive testing, and downhole energy harvesting. This paper will present recent developments of piezoelectric composite technology for high temperature and high power applications. The concerns and limitations of using piezoelectric composites will also be discussed, and the expected future research directions will be outlined. PMID:25111242

  13. 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

  14. Wettability and strength of InBiSn lead-free solder alloy on copper substrate

    Microsoft Academic Search

    Ervina Efzan Mhd Noor; Nurulakmal Mohd Sharif; Cheong Kuan Yew; Tadashi Ariga; Ahmad Badri Ismail; Zuhailawati Hussain

    2010-01-01

    This work studied the surface and interfacial properties of a proposed lead-free solder material, the In31.6Bi19.6Sn system. Surface tension and contact angle of In31.6Bi19.6Sn lead-free solder with melting temperature of 61.33C was measured on copper substrate at different reflow temperatures. Sessile drop measurements showed that the contact angle depended on reflow temperature. The contact angle gradually decreased from 38.34 to

  15. Developing a lead-free solder alloy Sn-Bi-Ag-Cu by mechanical alloying

    Microsoft Academic Search

    C. M. L. Wu; M. L. Huang; J. K. L. Lai; Y. C. Chan

    2000-01-01

    A new lead free alloy, Sn-6Bi-2Ag-0.5Cu, has been developed by mechanical alloying and has great potential as a lead-free\\u000a solder system. Initial trials on the manufacture of solder joints with this alloy revealed that a high quality bond with copper\\u000a could be formed. Its melting range of 193.87C to 209.88C is slightly higher than that of eutectic tin-lead solder. Examination

  16. 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.

  17. Piezoelectric Properties of Polycrystalline Lead Titanate Zirconate Compositions

    Microsoft Academic Search

    D. A. Berlincourt; C. Cmolik; H. Jaffe

    1960-01-01

    Detailed data are given for the piezoelectric, elastic, and dielectric properties of lead titanate zirconate ceramic compositions near the rhombohedral-tetragonal phase boundary. These compositions have markedly higher electromechanical coupling factors, remanent ferroelectric charge, and coercive field, than ceramic barium titanate. Another interesting feature is a pronounced change in the free permittivity 33T by the poling process; this change is in

  18. Piezoelectric transducer

    NASA Technical Reports Server (NTRS)

    Conragan, J.; Muller, R. S.

    1970-01-01

    Transducer consists of a hybrid thin film and a piezoelectric transistor that acts as a stress-sensitive device with built-in gain. It provides a stress/strain transducer that incorporates a signal amplification stage and sensor in a single package.

  19. Semiconductor/relaxor 03 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 03-type composites. This is achieved by introducing semiconducting ZnO particles into the relaxor ferroelectric 0.94Bi0.5Na0.5TiO30.06BaTiO3 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.

  20. Room Temperature Lead-Free Soldering of Microelectronic Components using a Local Heat Source

    Microsoft Academic Search

    Jonathan P. Levin; Timothy R. Rude; Jai Subramanian; Etienne Besnoin; Timothy P. Weihs; Omar M. Knio; David Van Heerden; Michael T. Powers; Christina D. Enns

    This paper describes a new joining process that enables fluxless, lead-free soldering of similar and dissimilar materials at room temperature with no thermal damage to surrounding components. The joining process is based on the use of a reactive multilayer foil as a local heat source. The foils are a new class of nano-engineered materials, which consist of thousands of alternating

  1. 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.

  2. 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

  3. A CASE STUDY FOR TRANSITIONING CLASS A SERVER MOTHERBOARDS TO LEAD-FREE

    Microsoft Academic Search

    R. Schueller; W. Ables; J. Fitch

    The EU RoHS legislation currently has an exemption to allow the continued use of lead based solder in Class A servers until at least 2010. There are industry proposals in place to extend this exemption to 2012 or beyond due to the added challenge of producing highly reliable lead-free server assemblies. Dell has surpassed the requirements of this legislation by

  4. 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...

  5. 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% ...

  6. 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...

  7. Investigation of Cr\\/Cu\\/Cu\\/Ni under bump metallization for lead-free applications

    Microsoft Academic Search

    K. C. Chan; Z. W. Zhong; K. W. Ong

    2002-01-01

    The elimination of lead in the solder flip-chip attachment material has necessitated many new studies on the reliability of the resultant systems. There are many lead-free solder material systems. However, most of them contain a large amount of tin. The tin in the solder reacts with the copper layer of the conventional UBM, depleting the UBM of copper, and causing

  8. Stress rupture of lead-free soldered joints used to assemble copper plumbing systems

    Microsoft Academic Search

    R. J. Fields; D. A. Shepherd; A. Cohen; A. G. Jr. Kireta

    1999-01-01

    A cooperative program on stress rupture behavior of lead-free soldered joints was initiated several years ago between the National Institute of Standards and Technology (NIST) and the Copper Development Association (CDA). It was created because the conservative code-assigned joint strength properties of soldered wrought and cast copper and copper alloy fittings prohibited the broader use of copper plumbing tube in

  9. Effects of multiple rework on the reliability of lead-free Ball Grid Array assemblies

    Microsoft Academic Search

    Hongtao Ma; Weidong Xie; Guhan Subbarayan; Kuo-Chuan Liu

    2011-01-01

    In this work, the effect of multiple rework cycles (up to 5x) on reliability of lead-free assemblies has been investigated. The test vehicle was designed to capture the reliability impact of rework processes on interconnects of BGA devices, the solder joints of its adjacent components and BGA devices of clamshelled devices. The effects on high aspect ratio plated through hole

  10. Investigation of Sn\\/Cu\\/Ni Ternary Alloying in Lead Free Solder Bump Applications

    Microsoft Academic Search

    Y. G. Jin; J. Meng; X. F. Chen; T. C. Wang

    2006-01-01

    Solder bump is widely used in advanced packaging. Solder joint reliability and solder reaction has been studied extensively. In particularly, the increasing usage of lead free solder bump has generated intensive investigation of optimizing under bump metallization (UBM) structures. In this paper, the effects and experimental results of IMC (intermetallic compound) in solder bump design will be presented. Besides the

  11. Study of under bump metallisation barrier layer for lead-free solder

    Microsoft Academic Search

    K. C. Chan; Z. W. Zhong; K. W. Ong

    2003-01-01

    The elimination of lead from solders for flip-chip attachment has necessitated many new studies on the reliability of the resultant systems. There are many lead-free solder material systems. However, most of them contain a large proportion of tin. The tin in the solder reacts with the copper layer present in some types of under bump metallisation (UBM) depleting the UBM

  12. The challenge of lead-free electronics for aerospace electronic systems

    Microsoft Academic Search

    Lloyd W. Condra; Stephan J. Meschter; David A. Pinsky; Anthony J. Rafanelli

    2009-01-01

    Driven by legislation resulting from two European Union directives, most commercial electronics manufacturers began delivering lead-free electronic components, assemblies, and equipment in 2006. Although not generally affected directly by the legislation, the aerospace industry is being swept along as its electronics supply chain makes the transition which significantly impacts the design, production, and support of aerospace electronic systems. Because of

  13. Piezoelectric Properties of Bismuth Layer-Structured Ferroelectric Ceramics with a Preferred Orientation Processed by the Reactive Templated Grain Growth Method

    Microsoft Academic Search

    Tsuguto Takeuchi; Toshihiko Tani; Yasuyoshi Saito

    1999-01-01

    Dense CaBi4Ti4O15 (CBT) and Na0.475Ca0.05Bi4.475Ti4O15 (NCBT) ceramics with a highly preferred {001} orientation were prepared by the reactive templated grain growth (RTGG) method. Plate-like Bi4Ti3O12 (BIT) particles were synthesized by a molten salt technique and used as the reactive template. The template particles were mixed with other oxide and carbonate powders and aligned by tape-casting. During the sintering, oriented CBT

  14. Properties of Bi4Ti3O12-(Na1\\/2Bi1\\/2)TiO3 Piezoelectric Ceramics

    Microsoft Academic Search

    Alessandra Sanson; Roger W. Whatmore

    2002-01-01

    Ceramics of the series (1-x)Bi4Ti3O12-x(Na1\\/2Bi1\\/2)TiO3 (BTO-NBT) were made using a conventional mixed oxide and carbonate process. The structural properties revealed that the system passes through the formation of Aurivillius compounds with increasing number of perovskite blocks for an increasing amount of NBT up to a maximum of four. Regions of coexistence of two layered compounds are also present. A perovskite

  15. 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.

  16. Dielectric spectroscopy of Dy2O3 doped (K0.5Na0.5)NbO3 piezoelectric ceramics

    NASA Astrophysics Data System (ADS)

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

    2014-06-01

    We report the dielectric properties of ( K 0.5 Na 0.5 ) NbO 3 ceramics doped with x wt% of Dy 2 O 3 (x= 0.0-1.5 wt%) using the broadband dielectric spectroscopy. The X-ray diffraction studies showed the formation of perovskite structure signifying that Dy 2 O 3 diffuse into the KNN lattice. Samples doped with x > 0.5 wt% exhibit smaller grain size and lower relative densities. The dielectric properties of KNN ceramics doped with Dy 2 O 3 are enhanced by increasing the Dy 3+ content; among the compositions studied, x = 0.5 wt% exhibited the highest dielectric constant and lowest loss at 1MHz over the temperature range of 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. At the request of all authors, and by agreement with the Proceedings Editors, a corrected version of this article was published on 19 June 2014. The full text of the Corrigendum is attached to the corrected article PDF file.

  17. Study of domain structure of poled (K,Na)NbO3 ceramics

    NASA Astrophysics Data System (ADS)

    Qin, Yalin; Zhang, Jialiang; Gao, Yong; Tan, Yongqiang; Wang, Chunlei

    2013-05-01

    Domain structure may greatly affect the dielectric and piezoelectric properties of a ferroelectric ceramic material. However, no investigations on the domain structure of poled (K,Na)NbO3-based ceramics have been reported so far. Since (K0.50Na0.50)NbO3 is the basic composition for the important type of lead-free piezoelectric materials, domain structure of the poled (K0.50Na0.50)NbO3 ceramics with the average grain size of about 8 ?m were explored by observing the domain patterns with an acid etching technique in this study. It was found that domain patterns show usually either a single set of parallel domain stripes or a few sets of parallel domain stripes in polycrystalline grains. The average domain widths in different sets of parallel domain stripes vary largely from 150 nm to 750 nm. The intersection angels between two adjacent sets of domain stripes are around 45 or 135. Two models of domain configuration were proposed to explain those domain patterns that consist of more than two sets of parallel domain stripes. One is built up in the way that the intersection angles between two adjacent sets of domain stripes are acute and consists of 90-, 60- and 120-domain walls. The other one is formed in the way that the intersection angles between two adjacent sets of domain stripes are obtuse and is composed of 180-, 90- and 120-domain walls. Additionally, the change of intersection angle between two adjacent sets of domain stripes with varying the observation plane is discussed.

  18. Modeling and reliability analysis of lead-free solder joints of bottom leaded plastic (BLP) package

    Microsoft Academic Search

    Chen Xiangyang; Zhou Dejian

    2006-01-01

    The electronic packaging and assembly technology is developing to high-density, fine-pitch and micromation. At the same time, an ever increasing need has developed for a lead-free solder joint interconnection due to the restrictions on the use of lead, and the upward spiraling market demand of green products. As a result the reliability of solder joint has attracted a great deal

  19. Modeling of interfacial intermetallic compounds in the application of very fine lead-free solder interconnections

    Microsoft Academic Search

    Zhiheng Huang; Paul P. Conway; Rongshan Qin

    2009-01-01

    Intermetallic compounds (IMCs) are formed between lead-free solders and base metals during soldering processes. The morphology\\u000a as well as the amount of the IMCs, in particular the interfacial IMCs, are important to mechanical performance of the solder\\u000a joints in their service environment. This is especially the case in state-of-art ultrafine-pitch wafer-level packaging, in\\u000a which solder joints could become as small

  20. Quantitative description of micro-structural changes in lead-free solder alloys

    Microsoft Academic Search

    Wolfgang H. Mller; Thomas Bhme

    2006-01-01

    The reliable behavior of solder joints is a well-known key issue for the microelectronic industry. From the technological point-of-view SMT solders guarantee the electrical and mechanical bonding on a printed circuit board. Recently, environmental tendencies turn the attention to lead-free materials, the properties of which still have to be studied. Moreover ongoing miniaturization and increasing functionalities of electronics require an

  1. Drop Impact Reliability Testing for Lead-Free and Leaded Soldered IC Packages

    Microsoft Academic Search

    D. Y. R. Chong; Kellin Ng; J. Y. N. Tan; P. T. H. Low; J. H. L. Pang; F. X. Che; B. S. Xiong; L. H. Xu

    2005-01-01

    Portable electronic products such as cellular phones, PDAs, and MP3 units are increasingly designed for accidental drop. Repeated drop events can lead to solder joint failure and malfunction of these products. Hence board-level reliability drop testing is a useful way to characterize the drop durability of the printed circuit board with different soldered assemblies. Lead-free (or Pb-free) solders are replacing

  2. Lead-free Solder Joint Reliability State of the Art and Perspectives

    Microsoft Academic Search

    Jianbiao Pan; Jyhwen Wang; David M. Shaddock

    2004-01-01

    There is an increasing demand in replacing tin-lead (Sn\\/Pb) solders with lead-free solders in the electronics industry due to health and environmental concern. The European Union recently passed a law to ban the use of lead in electronic products. The ban will go into effect in July of 2006. The Japanese electronics industry has worked to eliminate lead from consumer

  3. Drop impact reliability testing for lead-free and lead-based soldered IC packages

    Microsoft Academic Search

    Desmond Y. R. Chong; F. X. Che; John H. L. Pang; Ng Kellin; Jane Y. N. Tan; Patrick T. H. Low

    2006-01-01

    Portable electronic products such as cellular phones, PDAs, and MP3 units are increasingly designed for accidental drop. Repeated drop events can lead to solder joint failure and malfunction of these products. Hence board-level reliability drop testing is a useful way to characterize the drop durability of the printed circuit board with different soldered assemblies. Lead-free (or Pb-free) solders are replacing

  4. Lead-free Solder Joint Reliability State of the Art and Perspectives

    Microsoft Academic Search

    Jianbiao Pan; Jyhwen Wang; David M. Shaddock

    2005-01-01

    There is an increasing demand for replacing tin-lead (Sn\\/Pb) solders with lead-free solders in the electronics industry due to health and environmental concerns. The European Union recently passed a law to ban the use of lead in electronic products. The ban will go into effect in July of 2006. The Japanese electronics industry has worked to eliminate lead from consumer

  5. Board-level reliability of lead-free SnAgCu solder joint

    Microsoft Academic Search

    Jian-Shu Wu; Shan-Pu Yu; I-Hsuan Peng; Jong-Lih Wang; B. Chung

    2002-01-01

    Due to environmental concerns, the need for lead-free solutions in electronic components and systems is receiving increasing attention within the semiconductor and electronics industries. Sn-Ag-Cu systems are some of the more promising materials to replace the eutectic Sn-Pb solder. In this paper, a chip scale package assembled on board test and a notebook motherboard surface mount assembly were used to

  6. A novel mechanical shock test method to evaluate lead-free BGA solder joint reliability

    Microsoft Academic Search

    Dave Reiff; Edwin Bradley

    2005-01-01

    Portable electronic products such as cell phones are often subjected to drop tests to simulate consumer usage and to ensure required field reliability is met. Product-level drop tests can cause solder joint failures in both lead-free and tin-lead BGA packages due to the combination of highly localized strain created by high strain-rate mechanical shock. In order to understand this phenomenon

  7. Friction and wear behavior of a centrifugally cast lead-free copper alloy containing graphite particles

    Microsoft Academic Search

    M. Kestursatya; J. K. Kim; P. K. Rohatgi

    2001-01-01

    The tribological properties of a centrifugally cast lead-free copper alloy (C90300), containing an average of 13 vol pct graphite particles (5 m), have been studied. Friction tests were carried out at three different loads of 44, 88, and 176 N using a pin-on-disk testing method for the base copper alloy and the copper-graphite composite against a 1045 steel disk counterface.

  8. Friction and wear behavior of a centrifugally cast lead-free copper alloy containing graphite particles

    Microsoft Academic Search

    M. Kestursatya; J. K. Kim; P. K. Rohatgi

    2001-01-01

    The tribological properties of a centrifugally cast lead-free copper alloy (C90300), containing an average of 13 vol pct graphite\\u000a particles (5 m), have been studied. Friction tests were carried out at three different loads of 44, 88, and 176 N using a pin-on-disk testing\\u000a method for the base copper alloy and the copper-graphite composite against a 1045 steel disk counterface.

  9. An investigation of the recommended immersion tin thickness for lead-free soldering

    Microsoft Academic Search

    Sven Lamprecht

    2005-01-01

    Purpose This paper describes the different thickness measurement techniques that enable reliable thickness assessments, and the determination of the recommended immersion tin thickness for lead-free soldering. Design\\/methodology\\/approach Immersion tin layers were prepared with systematically varying layer thicknesses. The samples were annealed at different reflow profiles, used in assembly for tin\\/silver\\/copper (SAC-alloy) soldering. The layers were characterized with X-ray

  10. Development and validation of a lead-free alloy for solder paste applications

    Microsoft Academic Search

    Tommi Laine-Ylijoki; Hector Steen; Atso Forsten

    1997-01-01

    A lead-free solder alloy has been developed and, in form of a solder paste, validated for use in the assembly of surface mount printed circuit boards (PCB). Liquidus and solidus temperatures have been measured by thermal analysis and an optimum composition selected. Wetting balance tests have been done comparing the performance of the alloy with that of 60\\/40 tin\\/lead (SnPb),

  11. Optimising lead-free screen-printing and reflow process parameters

    Microsoft Academic Search

    Claire Ryan; S. O'Neill; J. Donovan; J. Punch; B. Rodgers; E. Murphy

    2004-01-01

    Introducing a lead-free solder replacement requires studies to be conducted by electronic assembly manufacturers in order to determine process alteration requirements and suitability of current equipment. This paper presents the results of an investigation of the screen-printing and reflow steps of the surface mount technology (SMT) manufacturing process. Experiments were conducted to investigate these two processes using a tin-silver-copper (95.5Sn3.8Ag0.7Cu)

  12. Development of SnZn lead-free solders bearing alloying elements

    Microsoft Academic Search

    Liang ZhangSong-bai; Song-bai Xue; Li-li Gao; Zhong Sheng; Huan Ye; Zheng-xiang Xiao; Guang Zeng; Yan Chen; Sheng-lin Yu

    2010-01-01

    SnZn solder alloys have been considered as one of the more attractive lead-free solders since it can easily replace SnPb\\u000a eutectic alloy without increasing the soldering temperature. However, there are still some problems to be resolved, such as\\u000a the argument about the poor oxidation resistance and embrittlement behavior. In order to overcome these drawbacks, and further\\u000a enhance the properties of

  13. Occurrence of tin pest on the surface of tin-rich lead-free alloys

    Microsoft Academic Search

    Agata Skwarek; Marcin Sroda; Mariusz Pluska; Andrzej Czerwinski; Jacek Ratajczak; Krzysztof Witek

    2011-01-01

    Purpose The purpose of this paper is to investigate tin pest formation in lead-free alloys. Design\\/methodology\\/approach Samples of Sn99.5Ag3.0Cu0.5, Sn99Cu1 and Sn98Cu2 alloys were prepared in four different forms. The first group was prepared using traditional PCB technology and a hand soldering method. The next group of samples was composed of as-received ingots of these alloys. To check

  14. Vibration testing of repaired lead-tin\\/lead-free solder joints

    Microsoft Academic Search

    Martin G. Perez; Matthew J. O'Keefe; Richard Colfax; Steve Vetter; Dale Murry; James Smith; David W. Kleine; Patricia Amick

    2006-01-01

    Due to growing environmental concerns and recent legislation, tin-lead (Pb-Sn) solders are being phased out by lead-free (LF) solders. The most common Sn-Pb replacement is the tin-silver-copper (Sn-Ag-Cu, SAC) alloys. During the transition phase, it is expected that there will be a period where both Sn-Pb and LF solders will be used side by side, and in conjunction with one

  15. Flexible pyroelectric nanogenerators using a composite structure of lead-free KNbO(3) nanowires.

    PubMed

    Yang, Ya; Jung, Jong Hoon; Yun, Byung Kil; Zhang, Fang; Pradel, Ken C; Guo, Wenxi; Wang, Zhong Lin

    2012-10-01

    Pyroelectric nanogenerators fabricated using a lead-free KNbO(3) nanowire-PDMS polymer composite are reported for the first time. The voltage/current output of the nanogenerators can be controlled by electric fields and enhanced by increasing the rate of change in temperature. The fabricated nanogenerators can be used to harvest energy from sunlight illumination and have potential applications in self-powered nanodevices and nanosystems. PMID:22837044

  16. The effect of polymer fill ratio in pillar structure for piezoelectric energy harvester

    NASA Astrophysics Data System (ADS)

    Lee, Kyoung-Soo; Shin, Dong-Jin; Chae, Moon-Soon; Koo, Sang-Mo; Ha, Jae-Geun; Koh, Jung-Hyuk; Cho, Kyung-Ho; Seo, Chang-Eui; Jeong, Soon-Jong

    2013-07-01

    One method of energy harvesting is to use piezoelectric devices, which are able to interchange electrical energy and mechanical strain or vibration. This study is to experimentally investigate the behavior of a piezoelectric energy harvester that was constructed with an array of pillar structures made of 0.2(PbMg1/3Nb2/3O3)-0.8(PbZr0.475Ti0.525O3) with polymer fill. Additionally, the aim of this study is to optimize the fill ratio of the composite piezoelectric ceramics and polymer structure. 0.2(PbMg1/3Nb2/3O3)-0.8(PbZr0.475Ti0.525O3) ceramics were employed as piezoelectric ceramic pillars, prepared in a rectangular shape. These piezoelectric ceramic pillars were sintered separately and attached to a bottom metallic electrode with poled states. The optimum ratio of ceramic pillar and elastic polymer ratio will be discussed. Piezoelectric properties will be discussed including the piezoelectric constant, piezoelectric voltage constants, and electromechanical coupling coefficient. We will present how the harvested energy depends on the lead resistor.

  17. Piezoelectric Effect

    NSDL National Science Digital Library

    In this activity, by the Concord Consortium's Molecular Literacy project, students explore the piezoelectric effect, which is the conversion between electricity and mechanical motion. The model used in this activity shows this conversion and users can manipulate the model to change the voltage and observe changes to a crystal. The activity itself is a java-based interactive resource built upon the free, open source Molecular Workbench software. In these activities, students are allowed to explore at their own pace in a digital environment full of demonstrations, illustrations, and models they can manipulate. In addition to the activity, visitors will find an overview of the activity and central and key concepts.

  18. 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

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

    PubMed

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

    2013-05-14

    Conventional composite sol-gel method has been modified to enhance the piezoelectric performance of ceramic thick films. Lead zirconate titanate (PZT) and lead magnesium niobate-lead titanate (PMN-PT) thick films were fabricated using the modified sol-gel method for ultrasonic transducer applications. In this work, piezoresponse force microscopy was employed to evaluate the piezoelectric characteristics of PZT and PMN-PT composite sol-gel thick films. The images of the piezoelectric response and the strain-electric field hysteresis loop behavior were measured. The effective piezoelectric coefficient (d33,eff) of the films was determined from the measured loop data. It was found that the effective local piezoelectric coefficient of both PZT and PMN-PT composite films is comparable to that of their bulk ceramics. The promising results suggest that the modified composite sol-gel method is a promising way to prepare the high-quality, crack-free ceramic thick films. PMID:23798771

  20. Design and characterization of piezoelectric ultrasonic motors

    NASA Astrophysics Data System (ADS)

    Yener, Serra

    This thesis presents modeling and prototype fabrication and characterization of new types of piezoelectric ultrasonic micromotors. Our approach in designing these piezoelectric motors was: (i) to simplify the structure including the poling configuration of piezoelectric elements used in the stator and (ii) to reduce the number of components in order to decrease the cost and enhance the driving reliability. There are two different types of piezoelectric motors designed throughout this research. The first of these designs consists of a metal tube, on which two piezoelectric ceramic plates poled in thickness direction, were bonded. Two orthogonal bending modes of the hollow cylinder were superimposed resulting in a rotational vibration. Since the structure and poling configuration of the active piezoelectric elements used in the stator are simple, this motor structure is very suitable for miniaturization. Moreover, a single driving source can excite two bending modes at the same time, thus generate a wobble motion. Three types of prototypes are included in this design. The piezoelectric stator structure is the same for all. However, the dimensions of the motors are reduced by almost 50 percent. Starting with a 10 mm long stator, we reached to 4 mm in the last prototype. The initial diameter was 2.4 mm, which was reduced to 1.6 mm. In the final design, the rotor part of the motor was changed resulting in the reduction in the number of components. In terms of driving circuit, a single driving source was enough to run the motors and a conventional switching power supply type resonant L-C circuit was used. A simple motor structure with a simple driving circuit were combined successfully and fabricated inexpensively. The second design is a shear type piezoelectric linear motor. The behavior of a single rectangular piezoelectric shear plate was analyzed and after optimizing the dimensions and the mode characteristics, a prototype was fabricated. The prototype consists of one layer of ceramic and a brass teeth-like layer bonded on it. The displacement was amplified with the metal layer, the teeth of which were placed on the points of in-phase motion. The targeted application area is paper-feeding mechanism. In terms of application areas for the first design, a gas valve system and a micro vehicle were constructed. In addition, a new optical coherence tomography endoscope by utilizing the piezoelectric micromotor was designed. Finally, the prototype motor was integrated inside the camera of a cell phone to drive the zoom mechanism.

  1. 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.

  2. Consideration of Impedance Matching Techniques for Efficient Piezoelectric Energy Harvesting

    Microsoft Academic Search

    Hyeoungwoo Kim; Shashank Priya; Harry Stephanou; Kenji Uchino

    2007-01-01

    This study investigates multiple levels of impedance-matching methods for piezoelectric energy harvesting in order to enhance the conversion of mechanical to electrical energy. First, the transduction rate was improved by using a high piezoelectric voltage constant (g) ceramic material having a magnitude of g33 = 40 times 10-3 V m\\/N. Second, a transducer structure, cymbal, was optimized and fabricated to

  3. Solgel synthesis and characterization of lead-free LNKN nanocrystalline powder

    Microsoft Academic Search

    Chao Wang; Yudong Hou; Haiyan Ge; Mankang Zhu; Hao Wang; Hui Yan

    2008-01-01

    A kind of lead-free nanocrystalline powder, (Li0.06Na0.47K0.47)NbO3 (LNKN), has been prepared by a newly developed solgel method using Nb2O5 as the Nb source. Phase analysis, microstructure and morphology of the powder were determined by X-ray diffraction (XRD), Fourier transform infrared (FTIR), Raman, transmission electron microscope (TEM) and high-resolution transmission electron microscopy (HRTEM). The experimental results showed that pure perovskite phase

  4. KNN\\/BNT composite lead-free films for high-frequency ultrasonic transducer applications

    Microsoft Academic Search

    Sien Lau; Hong Ji; Xiang Li; Wei Ren; Qifa Zhou; K. Shung

    2011-01-01

    Lead-free K0.5Na0.5NbO3\\/Bi0.5Na0.5TiO3 (KNN\\/ BNT) films have been fabricated by a composite sol-gel tech- nique. Crystalline KNN fine powder was dispersed in the BNT precursor solution to form a composite slurry which was then spin-coated onto a platinum-buffered Si substrate. Repeated layering and vacuum infiltration were applied to produce 5-m-thick dense composite film. By optimizing the sinter- ing temperature, the films

  5. 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.

  6. Stress rupture of lead-free soldered joints used to assemble copper plumbing systems

    SciTech Connect

    Fields, R.J.; Shepherd, D.A.; Cohen, A.; Kireta, A.G. Jr.

    1999-11-01

    A cooperative program on stress rupture behavior of lead-free soldered joints was initiated several years ago between the National Institute of Standards and Technology (NIST) and the Copper Development Association (CDA). It was created because the conservative code-assigned joint strength properties of soldered wrought and cast copper and copper alloy fittings prohibited the broader use of copper plumbing tube in building construction. Further, there was a challenge to the use of the only remaining code-approved solder because of a health concern.

  7. Properties of lead-free solder SnAgCu containing minute amounts of rare earth

    Microsoft Academic Search

    Zhigang Chen; Yaowu Shi; Zhidong Xia; Yanfu Yan

    2003-01-01

    Because of excellent wetting and mechanical properties, SnAgCu solder alloys have been regarded as the most promising Pb-free\\u000a substitutes for the SnPb solder. The Sn-3.8Ag-0.7Cu solder has garnered attention because of its creep resistance. However,\\u000a under the drives of increasingly finer pitch design and severe service conditions, novel lead-free solders with higher creep\\u000a performance may be needed. Adding a surface-active

  8. Electrical poling below coercive field for large piezoelectricity

    NASA Astrophysics Data System (ADS)

    Guo, Hanzheng; Ma, Cheng; Liu, Xiaoming; Tan, Xiaoli

    2013-03-01

    Isotropic polycrystalline ferroelectric ceramics have to be electrically poled to develop a net macroscopic polarization and hence piezoelectricity. It is well accepted that a sufficient poling can only be realized under an electric field that is much higher than the coercive field. In this study, we observed in (Bi1/2Na1/2)TiO3-BaTiO3 ceramics that large piezoelectricity can develop at poling fields far below the measured coercive field. Using in situ transmission electron microscopy, such an unusual behavior, is interpreted with the polarization alignment of polar nanodomains in the non-ergodic relaxor phase.

  9. Novel methods of powder preparation and ceramic forming for improving reliability of multilayer ceramic actuators

    Microsoft Academic Search

    William J. Dawson; Scott L. Swartz; Jean P. Issartel

    1993-01-01

    Critical components of many smart systems employ multilayer piezoelectric actuators based on lead zirconate titanate (PZT) ceramics. Applications include active vibration systems, noise suppression, acoustic camouflage, actuated structures, reconfigurable surfaces, and structural health monitoring. Two strategies involving novel materials processing techniques are discussed for improving the performance and reliability of PZT ceramic components. The first is the use of an

  10. Surface morphology and stress analysis of piezoelectric strontium-doped lead zirconate titanate thin films

    Microsoft Academic Search

    Sharath Sriram; Madhu Bhaskaran; Anthony S. Holland

    2007-01-01

    Strontium-doped lead zirconate titanate (PSZT) is a piezoelectric ceramic with relatively high values of piezoelectric coefficients. Perovskite oriented PSZT thin films are also reported to exhibit a variety of other properties including ferroelectricity and pyroelectricity. This paper reports on a study of the surface morphology and resulting stress of PSZT thin films, deposited under a variety of RF magnetron sputtering

  11. Recent developments in piezoelectric and electrostrictive sensors and actuators for smart structures

    Microsoft Academic Search

    L. Eric Cross

    1993-01-01

    Piezoelectricity will be defined phenomenologically and discussed pictorially to underscore the distinction between single crystal piezoelectrics and the poled ceramics which form the basis for most practical sensor and actuator systems. The classical lead zirconate: lead titanate (PZT) family is the most widely used. Recent advances in the understanding of the conventional morphotropic phase boundary (MPB) compositions are discussed with

  12. Direct strain energy harvesting in automobile tires using piezoelectric PZTpolymer composites

    Microsoft Academic Search

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

    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 ceramicpolymer composite piezoelectric materials

  13. 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.

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

    SciTech Connect

    Dittmer, Robert [Technische Universitat Darmstadt, Germany; Jo, Wook [Technische Universitat Darmstadt, Germany; Rdel, Jrgen [Technische Universitat Darmstadt, Germany; Kalinin, Sergei V [ORNL

    2012-01-01

    Piezoresponse force microscopy (PFM) is used to afford insight into the nanoscale electromechanical behavior of lead-free piezoceramics. Materials based on Bi{sub 1/2}Na{sub 1/2}TiO{sub 3} exhibit high strains mediated by a field-induced phase transition. Using the band excitation technique the initial domain morphology, the poling behavior, the switching behavior, and the time-dependent phase stability in the pseudo-ternary system (1-x)(0.94Bi{sub 1/2}Na{sub 1/2}TiO{sub 3}-0.06BaTiO{sub 3})-xK{sub 0.5}Na{sub 0.5}NbO{sub 3} (0 {le} x {ge} 18 mol%) are revealed. In the base material (x = 0 mol%), macroscopic domains and ferroelectric switching can be induced from the initial relaxor state with sufficiently high electric field, yielding large macroscopic remanent strain and polarization. The addition of KNN increases the threshold field required to induce long range order and decreases the stability thereof. For x = 3 mol% the field-induced domains relax completely, which is also reflected in zero macroscopic remanence. Eventually, no long range order can be induced for x {ge} 3 mol%. This PFM study provides a novel perspective on the interplay between macroscopic and nanoscopic material properties in bulk lead-free piezoceramics.

  15. 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.

  16. 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.

  17. 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.

  18. Creep Behavior of Lead-Free Sn-Ag-Cu + Ni-Ge Solder Alloys

    NASA Astrophysics Data System (ADS)

    Hidaka, N.; Watanabe, H.; Yoshiba, M.

    2009-05-01

    We developed a new lead-free solder alloy, an Sn-Ag-Cu base to which a small amount of Ni and Ge is added, to improve the mechanical properties of solder alloys. We examined creep deformation in bulk and through-hole (TH) form for two lead-free solder alloys, Sn-3.5Ag-0.5Cu-Ni-Ge and Sn-3.0Ag-0.5Cu, at elevated temperatures, finding that the creep rupture life of the Sn-3.5Ag-0.5Cu-Ni-Ge solder alloy was over three times better than that of the Sn-3.0Ag-0.5Cu solder at 398 K. Adding Ni to the solder appears to make microstructural development finer and more uniform. The Ni added to the solder readily combined with Cu to form stable intermetallic compounds of (Cu, Ni)6Sn5 capable of improving the creep behavior of solder alloys. Moreover, microstructural characterization based on transmission electron microscopy analyses observing creep behavior in detail showed that such particles in the Sn-3.5Ag-0.5Cu-Ni-Ge solder alloy prevent dislocation and movement.

  19. Thermal cycling fatigue model development for FBGA assembly with Sn-Ag-based lead-free solder

    Microsoft Academic Search

    Fa-Xing Che; Jing-En Luan; Daniel YAP; Kim-Yong Goh; Xavier BARATON

    2008-01-01

    With the increasing requirement for lead-free solders, it is desired to know how different solder alloys affect on reliability of microelectronic assembly. Some fatigue life models for Sn-Ag-Cu (SAC) solder have been developed by researchers. The Ni-dopant lead free solder is increasingly used in electronic packages due to its good drop performance. Currently, it lacks the fatigue life model for

  20. THE IMPACT OF LEAD-FREE REFLOW TEMPERATURES ON THE MOISTURE SENSITIVITY PERFORMANCE OF PLASTIC SURFACE MOUNT PACKAGES

    Microsoft Academic Search

    B. T. Vaccaro; R. L. Shook; D. L. Gerlach

    Environmental concerns continue to drive the demand for lead-free products in the electronics industry. Board assembly operations currently use near eutectic tin-lead solders to attach components to printed circuit boards. Lead- free solder alloys which have been identified as substitutes for tin-lead solders have melting points that are typically 30- 40C higher. Therefore, peak reflow temperatures must be increased to

  1. Multilayer modal actuator-based piezoelectric transformers.

    PubMed

    Huang, Yao-Tien; Wu, Wen-Jong; Wang, Yen-Chieh; Lee, Chih-Kung

    2007-02-01

    An innovative, multilayer piezoelectric transformer equipped with a full modal filtering input electrode is reported herein. This modal-shaped electrode, based on the orthogonal property of structural vibration modes, is characterized by full modal filtering to ensure that only the desired vibration mode is excited during operation. The newly developed piezoelectric transformer is comprised of three layers: a multilayered input layer, an insulation layer, and a single output layer. The electrode shape of the input layer is derived from its structural vibration modal shape, which takes advantage of the orthogonal property of the vibration modes to achieve a full modal filtering effect. The insulation layer possesses two functions: first, to couple the mechanical vibration energy between the input and output, and second, to provide electrical insulation between the two layers. To meet the two functions, a low temperature, co-fired ceramic (LTCC) was used to provide the high mechanical rigidity and high electrical insulation. It can be shown that this newly developed piezoelectric transformer has the advantage of possessing a more efficient energy transfer and a wider optimal working frequency range when compared to traditional piezoelectric transformers. A multilayer piezoelectric, transformer-based inverter applicable for use in LCD monitors or portable displays is presented as well. PMID:17328332

  2. Novel rare-earth-containing lead-free solders with enhanced ductility

    NASA Astrophysics Data System (ADS)

    Dudek, M. A.; Sidhu, R. S.; Chawla, N.

    2006-06-01

    Severallead-free material systems are availableas replacements for traditional lead-based solders in microelectronic packaging, including near-eutectic combinations oftin-rich alloys. Although these materials have superior mechanical properties as compared to the Pb-Sn system, much work remains in developing these materials for electronic packaging. Small additions of rare-earth elements have been shown to refine the microstructure of several lead-free solder systems, thus improving their mechanical properties. This study investigated the effect of the addition of lanthanum on the melting behavior, microstructure, and shear strength of an Sn-3.9Ag-0.7Cu alloy. The influence of LaSn3 intermetallics on microstructural refinement and damage evolution in these novel solders is discussed.

  3. KNN/BNT composite lead-free films for high-frequency ultrasonic transducer applications.

    PubMed

    Lau, Sien Ting; Ji, Hong Fen; Li, Xiang; Ren, Wei; Zhou, Qifa; Shung, K Kirk

    2011-01-01

    Lead-free K(0.5)Na(0.5)NbO(3)/Bi(0.5)Na(0.5)TiO(3) (KNN/ BNT) films have been fabricated by a composite sol-gel technique. Crystalline KNN fine powder was dispersed in the BNT precursor solution to form a composite slurry which was then spin-coated onto a platinum-buffered Si substrate. Repeated layering and vacuum infiltration were applied to produce 5-?m-thick dense composite film. By optimizing the sintering temperature, the films exhibited good dielectric and ferroelectric properties comparable to PZT films. A 193-MHz high-frequency ultrasonic transducer fabricated from this composite film showed a -6-dB bandwidth of approximately 34%. A tungsten wire phantom was imaged to demonstrate the capability of the transducer. PMID:21244994

  4. 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.

  5. 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

  6. 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. [School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100 (China)

    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.

  7. 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.

  8. Low Temperature Sintering and Piezoelectric Properties in Pb(ZrxTi1-x)O3-Pb(Zn1/3Nb2/3)O3-Pb(Ni1/3Nb2/3)O3 Ceramics

    NASA Astrophysics Data System (ADS)

    Ahn, Cheol-Woo; Song, Hyun-Cheol; Park, Seung-Ho; Nahm, Sahn; Uchino, Kenji; Priya, Shashank; Lee, Hyeung-Gyu; Kang, Nam-Kee

    2005-03-01

    High-power ceramics of the composition 0.8Pb(Zr0.5Ti0.5)O3-0.2Pb[(Zn0.8Ni0.2)1/3Nb2/3]O3 (0.8PZT-0.2PZNN) + 0.5 wt% MnO2 have excellent piezoelectric and dielectric properties such as d33=320 pC/N, {\\varepsilon33}T/\\varepsilono=1227, kp=0.54, and Qm=1265. However, the sintering temperature of this composition is high, approximately 1200C, restricting the use of cheap base metal electrodes in the fabrication of multilayer components. In this study, we provide a solution to this problem and report a low sintering temperature high-power composition in a PZT-PZNN system. CuO and Al2O3 were selected as sintering agents. It was found that the addition of CuO can reduce the sintering temperature to 920C, but it can also significantly reduce the piezoelectric properties. The reduction of Qm magnitude was 81% when 0.5 wt% CuO was added. The addition of Al2O3 as a sintering agent was found to improve Qm magnitude but significant reductions in piezoelectric and dielectric properties were observed. The addition of excess ZnO and NiO was found to improve the density and piezoelectric properties, but it was also found to reduce Qm magnitude. Consequently, the optimization of the concentration of the sintering agents was carried out, and the optimized low sintering temperature high-power composition was found to be 0.875Pb(Zr0.5Ti0.5)O3-0.125Pb[(Zn0.8Ni0.2)1.5/3Nb2/3]O3 + 0.5 wt% MnO2 + 0.2 wt% CuO + 0.3 wt% Al2O3. The piezoelectric properties of the specimens of this composition sintered at 920C were found to be kp=0.581, Qm=809, d33=345 pC/N, {\\varepsilon3}T/\\varepsilono=1345, and Tc=330C.

  9. Study of the Interface Microstructure of Sn-Ag-Cu Lead-Free Solders and the Effect of Solder Volume on Intermetallic Layer Formation.

    E-print Network

    Ekere, Ndy

    -fine pitch flip-chip applications. Key words: Lead-free soldering, tin-silver-copper alloys, intermetallic that the Sn- Ag-Cu alloy is one of the promising lead-free alloys currently being evaluated by industryStudy of the Interface Microstructure of Sn-Ag-Cu Lead-Free Solders and the Effect of Solder Volume

  10. Thermal deformation compensation of a composite beam using piezoelectric actuators

    Microsoft Academic Search

    G. Song; X. Zhou; W. Binienda

    2004-01-01

    Maintaining the surface shape of precision structures such as spacecraft antenna reflectors has been a challenging task. Surface errors are often introduced by thermal distortions due to temperature differences. This paper presents numerical and experimental results of active compensation of thermal deformation of a composite beam using piezoelectric ceramic actuators. To generate thermal distortion of the composite beam, two film

  11. Thermal deformation compensation of a composite beam using piezoelectric actuators

    Microsoft Academic Search

    Xiaoqin Zhou; Gangbing Song; W. Binienda

    2002-01-01

    Maintaining surface shape of precision structures such as spacecraft antenna reflectors has been a challenging task. The surface errors are often introduced by thermal distortions due to temperature differences. This paper presents numerical and experimental results of active compensation of thermal deformation of a composite beam using piezoelectric ceramic actuators. To generate thermal distortion to the composite beam, two film

  12. Piezoelectric Energy Harvesting under High PreStressed Cyclic Vibrations

    Microsoft Academic Search

    Hyeoung Woo Kim; Shashank Priya; Kenji Uchino; Robert E. Newnham

    2005-01-01

    Cymbal transducers have been found as a promising structure for piezoelectric energy harvesting under high force (? 100 N) at cyclic conditions (? 100200 Hz). The thicker steel cap enhances the endurance of the ceramic to sustain higher ac loads along with stress amplification. This study reports the performance of the cymbal transducer under ac force of 70 N with

  13. Effective moduli of granular and layered composites with piezoelectric constituents

    NASA Astrophysics Data System (ADS)

    Olson, Tamara; Avellaneda, Marco

    1993-07-01

    The effective elastic and dielectric moduli of a composite made from piezoelectric materials are examined, with particular emphasis on applications to unpoled piezoelectric ceramics and layered materials. Explicit formulae for the effective moduli and coupling of a layered material are derived. A self-consistent estimate of the moduli of an isotropic polycrystal is obtained through an effective medium approximation (EMA), which takes into account the interaction between each individual grain and the surrounding composite. This estimate shows that the grains behave as uncoupled grains with electric and elastic constants modified by the behavior of surrounding grains. A similar effect is also observed in bounds (established via classical variational principles) on the moduli of a statistically isotropic polycrystal. Numerical implementation of the EMA and bounds show good agreement with data for unpoled barium titanate ceramic. For a general composite with piezoelectric constituents, it is shown that the effective electromechanical coupling can be bounded by the largest coupling factor of the components.

  14. High thermal stability of piezoelectric properties in (Na{sub 0.5}Bi{sub 0.5}TiO{sub 3}){sub x}-(BaTiO{sub 3}){sub y}-(Na{sub 0.5}K{sub 0.5}NbO{sub 3}){sub 1-x-y} ceramics

    SciTech Connect

    Gupta, Shashaank; Priya, Shashank [Bio-Inspired Materials and Devices Laboratory (BMDL), Center for Energy Harvesting Materials and Systems (CEHMS), Virginia Tech, Blacksburg, Virginia 24061 (United States)] [Bio-Inspired Materials and Devices Laboratory (BMDL), Center for Energy Harvesting Materials and Systems (CEHMS), Virginia Tech, Blacksburg, Virginia 24061 (United States)

    2013-01-07

    We report the piezoelectric and ferroelectric properties of (Na{sub 0.5}Bi{sub 0.5}TiO{sub 3}){sub x}-(BaTiO{sub 3}){sub y}-(Na{sub 0.5}K{sub 0.5}NbO{sub 3}){sub 1-x-y} ceramics for Na{sub 0.5}K{sub 0.5}NbO{sub 3} rich end of composition (x, y {<=} 0.04 mol. %). These compositions were found to exhibit significantly improved thermal stability of piezoresponse. Variation of dielectric constant as a function of temperature revealed that orthorhombic-tetragonal (T{sub o-t}) and tetragonal-cubic (T{sub c}) transition temperatures for these compositions were in the vicinity of 0 Degree-Sign C and 330 Degree-Sign C, respectively. Dynamic scaling and temperature dependent X-ray diffraction analysis were conducted. Results are discussed in terms of intrinsic and extrinsic contributions to the piezoelectric response explaining the temperature dependent behavior.

  15. Characterization of piezoelectric paint and its refinement for structural health monitoring applications

    NASA Astrophysics Data System (ADS)

    Yang, Cheng; Fritzen, Claus-Peter

    2012-04-01

    Piezoelectric paint is a composite piezoelectric material, due to its outstanding properties consisting of flexibility and conformability, it has been a great interest in structural health monitoring applications recently. The normal piezoelectric ceramics offer high piezoelectric properties, but are difficult to adhere on curly structural surfaces. For normal polymers, it offers high flexibility but missing the ability to transform the mechanical energy into the electrical energy, and vice versa. The piezoelectric paint combines the features of both, so it could be distributed on both even and uneven structural surface, as a sensor or actuator. This work starts with the development of the piezoelectric paint, followed by a systematic characterization of its mechanical and piezoelectric properties, which includes microstructure, Young's modulus, sensitivity and piezoelectric charge constant da1. The characterization results helps to understand the performance of the piezoelectric paint more deeply. Finally, a refinement method is demonstrated to improve the piezoelectricity of the paint. The results showed that the piezoelectricity was greatly improved and therefore its applications in structural health monitoring is widely expanded.

  16. Characterization of piezoelectric paint and its refinement for structural health monitoring applications

    NASA Astrophysics Data System (ADS)

    Yang, Cheng; Fritzen, Claus-Peter

    2011-11-01

    Piezoelectric paint is a composite piezoelectric material, due to its outstanding properties consisting of flexibility and conformability, it has been a great interest in structural health monitoring applications recently. The normal piezoelectric ceramics offer high piezoelectric properties, but are difficult to adhere on curly structural surfaces. For normal polymers, it offers high flexibility but missing the ability to transform the mechanical energy into the electrical energy, and vice versa. The piezoelectric paint combines the features of both, so it could be distributed on both even and uneven structural surface, as a sensor or actuator. This work starts with the development of the piezoelectric paint, followed by a systematic characterization of its mechanical and piezoelectric properties, which includes microstructure, Young's modulus, sensitivity and piezoelectric charge constant da1. The characterization results helps to understand the performance of the piezoelectric paint more deeply. Finally, a refinement method is demonstrated to improve the piezoelectricity of the paint. The results showed that the piezoelectricity was greatly improved and therefore its applications in structural health monitoring is widely expanded.

  17. Piezoelectric dilatometric analysis using homodyne and heterodyne laser interferometry

    NASA Astrophysics Data System (ADS)

    Delahoussaye, Keith

    The electromechanical coupling of piezoelectric materials has been widely studied since such property is found to be a key element of enhanced sensitivity in piezoelectric sensors or actuators. However a unified view of this coupling as function of frequencies verified using multiple measurement techniques has not previously been available. This study examines and compares multiple optical based homodyne and heterodyne interferometry techniques for piezoelectric displacement measurement, over a wide range of frequencies from DC to 20 MHz. A custom configured homodyne optical interferometer and a commercial heterodyne Laser Doppler Vibrometer are used in the study. Because the frequency ranges used by these devices overlap, it is possible to compare the results. Ferroelectric lead titanate PbTiO3 (PT) ceramic sample with high ferroelectric strain is studied in this work. Frequency dependence of the electromechanical displacement is obtained using multiple techniques and the emphasis of the interrogations is given to frequencies near piezoelectric resonances.

  18. Architectured Materials to Improve the Reliability of Power Electronics Modules: Substrate and Lead-Free Solder

    NASA Astrophysics Data System (ADS)

    Kaabi, Abderrahmen; Bienvenu, Yves; Ryckelynck, David; Pierre, Bertrand

    2013-07-01

    Power electronics modules (>100 A, >500 V) are essential components for the development of electrical and hybrid vehicles. These modules are formed from silicon chips (transistors and diodes) assembled on copper substrates by soldering. Owing to the fact that the assembly is heterogeneous, and because of thermal gradients, shear stresses are generated in the solders and cause premature damage to such electronics modules. This work focuses on architectured materials for the substrate and on lead-free solders to reduce the mechanical effects of differential expansion, improve the reliability of the assembly, and achieve a suitable operating temperature (<175C). These materials are composites whose thermomechanical properties have been optimized by numerical simulation and validated experimentally. The substrates have good thermal conductivity (>280 W m-1 K-1) and a macroscopic coefficient of thermal expansion intermediate between those of Cu and Si, as well as limited structural evolution in service conditions. An approach combining design, optimization, and manufacturing of new materials has been followed in this study, leading to improved thermal cycling behavior of the component.

  19. 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.

  20. High temperature indentation behavior of eutectic lead-free solder materials

    NASA Astrophysics Data System (ADS)

    Mllera, W. H.; Worrack, H.

    2010-06-01

    Electronic malfunction caused by thermal stresses is one major problem in modern electronic industries. Therefore, the precise knowledge of the mechanical solder material properties as a function of temperature is required. Nanoindentation and its potential of recording load-displacement curves is a widely-used miniature test for the determination of Youngs modulus and hardness values. Furthermore, such tests can be performed in a temperature range from Room Temperature (RT) up to +500C by using a Hot-Stage add on. In this paper the lead-free solder alloys Sn91Zn9 and Sn42Bi58, and also copper and fused silica, which is used for the indenter calibration are investigated. The results for quartz and copper agree with the published values in several references. However, the Youngs modulus of Sn42Bi58 as a function of temperature differs from the values presented in the literature. Due to delayed material response in the unloading regime it must be assumed that creep effects lead to an incorrect automatic data evaluation. Investigation and understanding of the creep behavior is part of this paper. For this purpose a visco-elastic material model is used to model the indentation response at elevated temperatures and to determine the corresponding viscous material constants.

  1. PIEZOELECTRIC POWER SCAVENGING OF MECHANICAL VIBRATION ENERGY

    E-print Network

    Ervin, Elizabeth K.

    with other smart materials for power harvesting #12;Piezoelectric MaterialsPiezoelectric MaterialsPIEZOELECTRIC POWER SCAVENGING OF MECHANICAL VIBRATION ENERGY PIEZOELECTRIC POWER SCAVENGING and magneticand magnetic field.field. Piezoelectric Materials as Smart Material- Among the all smart materials

  2. 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

  3. Processing and characterization of high Q m ferroelectric ceramics

    Microsoft Academic Search

    C Galassi; E Roncari; C Capiani; F Craciun

    1999-01-01

    Use of ferroelectric ceramics in applications like piezoelectric transformers was made possible by the development of new materials with high electromechanical coupling coefficients and high mechanical quality factor. Hard ferroelectric ceramics of complex composition based on lead zirconate titanate with Nb, Mg, Mn and Li additives have been prepared. The perovskitic phase was produced by solid phase reaction of the

  4. Lead Titanate and Lead Metaniobate Porous Ferroelectric Ceramics

    Microsoft Academic Search

    A. N. RYBJANETS; O. N. RAZUMOVSKAJA; L. A. REZNITCHENKO; V. D. KOMAROV; A. V. TURIK

    2004-01-01

    A manufacturing technology of porous ferroelectric ceramics on the base of pure and modified lead titanate and lead metaniobate compositions were developed. Special attention was given to the microstructure studying of porous ceramics with different porosity types. The porosity dependencies of elastic, dielectric and piezoelectric properties of the specified compositions were measured in 040% relative porosity range. It was shown

  5. Photostriction of SolGel Processed PLZT Ceramics

    Microsoft Academic Search

    A Dogan; A V Prasadarao; K Uchino; Patcharin Poosanaas; S Komarneni

    1997-01-01

    Lanthanum-modified lead zirconate titanate (PLZT) ceramic materials have gained considerable attention due to their photostriction, which is the superposition of photovoltaic and piezoelectric effects. However, the photovoltaic effect and the induced strain response are also influenced by the fabrication and processing conditions. The PLZT ceramics produced by conventional oxide mixing process exhibit moderate photostrictive properties due to the inhomogeneous distribution

  6. Ceramic - Polymer Nanocomposite: Alternate Choice of Bone (Review)

    Microsoft Academic Search

    Debasish Sarkar; Min Cheol Chu; Seong Jai Cho

    This study evaluates a range of materials that may be used to design prostheses for bone. It is found that nanocrystalline ceramic-polymer composite could be the best material for prosthetic bone with respect to biocompatibility, morphology, chemistry, and compatibility with the piezoelectric and mechanical behavior of long human bones, such as the femur. Keyword: Bone, Prosthesis, Nanocomposite, Ceramic, Polymer

  7. 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.

  8. Design and processing of multi-layered flextensional piezoelectric actuators

    NASA Astrophysics Data System (ADS)

    Vartuli, James Scott

    Piezoelectric actuators are unique to other actuator systems due to their fast response time (10-4 s) and displacement accuracy on the order of a nanometer. Piezoelectric strain is obtained with the application of an electric field. Useful applications include adaptive optical systems and active vibration dampening. One type of piezoelectric actuator is the flextensional device, which requires a gradient in electromechanical properties to create a bending moment through non-uniform lateral stresses. The simplest flextensional device, called the unimorph, is a piezoelectric bonded to a metal plate. The bond between piezoelectric and metal is subjected to stresses that can lead to lifetime limitations. Fabrication requires cutting, polishing, and bonding, which does not facilitate miniaturization and curved shell structures. The monomorph and RAINBOW are modifications of the unimorph that seek to improve upon these drawbacks. The monomorph is comprised of one plate of normally insulating piezoelectric that is made semiconductive with a dopant. With an applied field, a non-uniform electric-field distribution arises due to the semiconductor-electrode interface. Removal of the difficult tasks of surface preparation and bonding are processing advantages that better enable component miniaturization. RAINBOW removes potential interface problems of bonding dissimilar materials together by creating a metal-ceramic layer within the piezoelectric ceramic by chemically reducing the oxygen content. The processing methods of the monomorph and RAINBOW are limited since they can only create one functional gradient. Our work sought to create a modification of the unimorph with the capability for miniaturization while maintaining the positive attributes of the previously mentioned technologies. Called PrinDrex, named for the collaborative effort between Princeton and Drexel Universities, we construct functional gradients by layering different ceramic-polymer tapes in an appropriate order. We construct 'custom-made' actuators by layering ceramics with different piezoelectric constants and electrical properties. After sintering this fully ceramic laminate only requires electrode application and poling to function. No post-sintering steps are required, which better enables the fabrication of large and small devices. PrinDrex is capable of generating displacements and forces equivalent to the best commercially available flextensional devices. We characterized with electron microscopy and modeled and predicted actuator performance with finite element analysis.

  9. Kelvin and piezoelectricity

    NASA Astrophysics Data System (ADS)

    Trainer, Matthew

    2003-09-01

    This paper presents a rsum of the history of piezoelectricity during the 19th and 20th centuries. By examining the experiments, concepts and theories presented in Lord Kelvin's scientific communications and those of his contemporaries, this paper aims to show that he played an important role in the development of piezoelectricity. Kelvin's contribution was that he produced the measurement instrumentation that led to the discovery of piezoelectricity and laid some of the essential theoretical groundwork that led to the important applications of piezoelectricity in the 20th century.

  10. Atomisti modeling of the microstructure and transport properties of lead-free solder alloys

    NASA Astrophysics Data System (ADS)

    Sellers, Michael S.

    Damage mechanics models of lead-free solder joints in nanoelectronics continue to improve, and in doing so begin to utilize quantitative values describing processes at the atomic level, governing phenomena like electromigration and thermomigration. In particular, knowledge of the transport properties of specific microstructures helps continuum level models fully describe these larger-scale damage phenomena via multi-scale analysis. For example, diffusivities for different types of grain boundaries (fast diffusion paths for solvent and solute atoms, and vacancies), and a description of the boundary structure as a function of temperature, are critical in modeling solder microstructure evolution and, consequently, joint behavior under extreme temperature and electric current. Moreover, for damage that develops at larger length scales, surface energies and diffusivities play important roles in characterizing void stability and morphology. Unfortunately, experiments that investigate these kind of damage phenomena in the atomistic realm are often inconsistent or unable to directly quantify important parameters. One case is the particular transport and structural properties of grain boundaries in Sn (the main component in lead-free solder alloys) and their behavior in the presence of Ag and Cu impurities. This information is crucial in determining accurate diffusivity values for the common SnAgCu (SAC) type solder. Although an average grain boundary diffusivity has been reported for polycrystalline Sn in several works, the value for grain boundary width is estimated and specific diffusivities for boundaries known to occur in Sn have not been reported, to say nothing of solute effects on Sn diffusivity and grain boundary structure. Similarly, transport properties of Sn surfaces remain relatively uninvestigated as well. These gaps and inconsistencies in atomistic data must be remedied for micro- and macro-scale modeling to improve. As a complement to experimental work and possessing the ability to fill in the gaps, molecular simulation serves to reinforce experimental predictions and provide insight into the atomistic processes that govern studied phenomena. In the present body of work, we employ molecular statics and dynamics simulations in the characterization and computation of betaSn surface energies and surface diffusivities, the determination of diffusivities and structural properties of specific betaSn grain boundaries, and the investigation of Cu and Ag solute effects on betaSn grain boundaries. In our study of betaSn surfaces, energies for low number Miller index surfaces are computed and the (100) plane is found to have the lowest un-relaxed energy. We then find that two simple hopping mechanisms dominate adatom diffusion transitions on this surface. For each, we determine hopping rates of the adatom and compute its tracer diffusivity. Our work on grain boundaries investigates the self-diffusion properties and structure of several betaSn symmetric tilt grain boundaries using molecular dynamics simulations. We find that larger diffusive widths are exhibited by higher excess potential energy grain boundaries. Diffusivities in the directions parallel to the interface plane are also computed and activation energies are found with the Arrhenius relation. These are shown to agree well with experimental data. Finally, we examine the effect that solute atoms of Ag and Cu have on the microstructure of betaSn. Excess energies of the (101) symmetric tilt betaSn grain boundary are computed as a function of solute concentration at the interface, and we show that Ag lowers the energy at a greater rate than Cu. We also quantify segregation enthalpies and critical solute concentrations (where the excess energy of the boundary is reduced to zero). The effect of solute type on shear stress is also examined, and we show that solute has a strong effect on the stabilization of higher energy grain boundaries under shear stress. We then look at the self-diffusivity of Sn in the (101) symmetric tilt betaSn grain boundary and show that adding b

  11. Antiferroelectricity induced by electric field in NaNbO3-based lead-free Yonghao Xu,1,2

    E-print Network

    Hong, Wei

    -free polycrystalline ceramic. Such an unlikely ferroelectric-to-antiferroelectric phase transition occurs at fieldsZrO3-based ceramics can exist either in the antifer- roelectric or ferroelectric state at room. Exposure to a strong electric field transforms the ceramic into a metastable ferroelectric phase. Following

  12. Friction and wear behavior of a centrifugally cast lead-free copper alloy containing graphite particles

    NASA Astrophysics Data System (ADS)

    Kestursatya, M.; Kim, J. K.; Rohatgi, P. K.

    2001-08-01

    The tribological properties of a centrifugally cast lead-free copper alloy (C90300), containing an average of 13 vol pct graphite particles (5 m), have been studied. Friction tests were carried out at three different loads of 44, 88, and 176 N using a pin-on-disk testing method for the base copper alloy and the copper-graphite composite against a 1045 steel disk counterface. The friction coefficient, temperature rise, and weight loss of the pin and disk were measured. To understand the wear mechanism, the wear debris and the surfaces of the pin and the disk were analyzed before and after the tests, using scanning electron microscope (SEM) and energy-dispersive X-ray (EDX) analysis. The friction coefficient of the copper-graphite pins was lower than that of the base-alloy pins for all applied loads, which was attributed to the presence of the graphite in the matrix. It was also observed that the presence of graphite in the matrix reduces the transfer of iron from the counterface to the pins, but enhances the transfer of materials from the pins to the counterface. The temperature rise in the counterface running against the base-alloy pins was larger than the temperature rise in the counterface running against the copper-graphite pins, both tested under similar conditions. In addition, the effect of element transfer on the friction coefficient, variations in the weight of the pins and the counterface, as well as the surface roughness, are attributed to the formation of a graphitic tribolayer on the surface of the copper-graphite pins. An isostrain model predicting the friction coefficient of the composites is proposed, which agrees well with the measurements in the present article as well as with measurements made by other investigators.[10

  13. 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.

  14. Effect of Ceramic Processing Methods on Photostrictive Ceramics

    Microsoft Academic Search

    P. Poosanaas; A. Dogan; A. V. Prasadarao; S. Komarneni; K. Uchino

    1999-01-01

    Lanthanum-modified lead zirconate titanate (PLZT) ceramics (3\\/52\\/48) doped with 0.5 at.% WO3 were prepared by three different processing methods, coprecipitation, sol-gel and conventional oxide mixing techniques, to investigate the effect of processing route on photovoltaic and photostrictive properties. The piezoelectric constant (d33) was observed to be independent of processing technique. Photovoltaic and photo-induced strain were found to get enhanced with

  15. The popcorn effect of lead and lead-free mixed assembly process in high density plastic packages

    Microsoft Academic Search

    Xiao Hong; Ping Lai

    2011-01-01

    The expansion of integrated circuit applications is driving chip costs down. To respond to the lower price the lower price expectations, manufacturers bring Plastic packages which is cost less expensive packaging solutions. Today although the electronic packaging industry there are still many enterprises were to have lead solder, but this does not preclude the lead-free has become the main topic

  16. Mechanical properties and microstructure investigation of Sn-Ag-Cu lead free solder for electronic package applications

    Microsoft Academic Search

    Qing Wang

    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

  17. Assembly and solder joint reliability of plastic ball grid array with lead-free versus lead-tin interconnect

    Microsoft Academic Search

    K.-M. Levis; A. Mawer

    2000-01-01

    Many governments, particularly in Japan and Europe, have proposed laws reducing or eliminating the use of lead (Pb) and other toxic substances in products in an effort to decrease landfill pollution and ground water contamination. Thus, there exists a need for lead-free components in order to comply with government standards and to meet market demands for green products. As the

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

    SciTech Connect

    Syh, J [Willis-Knighton Medical Center, Shreveport, LA (United States)

    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. Fabrication and Electrical Properties of Potassium Niobate Ferroelectric Ceramics

    Microsoft Academic Search

    Hajime Nagata; Kenji Matsumoto; Tadayuki Hirosue; Yuji Hiruma; Tadashi Takenaka

    2007-01-01

    Potassium niobate, KNbO3 (KN), ceramics were prepared by a modified conventional ceramic fabrication process to characterize their piezoelectric properties. The modified process involving two-stage calcination (first stage at 600 C and second stage at 1000 C) is very effective in obtaining KN ceramics with a high density ratio >96% and a high resistivity, rho, of >1012 Omega\\\\cdotcm and that are

  20. Nonplanar piezoelectric film structures

    Microsoft Academic Search

    Seppo Leppvuori; Arvi Kruusing; Antti Uusimki

    1999-01-01

    Microengineered, non-planar piezoelectric structures can offer solutions to a variety of challenging problems arising in the microsystem technologies. Besides the piezoelectric polymers, which can easily be shaped, there has also been significant progress in developing fabrication technologies based on thin layers of the lead zirconate titanate family of piezoceramics. The processing methods include dip-casting, printing, cathodic electrosynthesis, electrolytic

  1. Piezoelectric energy harvesting

    Microsoft Academic Search

    Christopher A Howells

    2009-01-01

    Piezoelectric materials can be used to convert oscillatory mechanical energy into electrical energy. This technology, together with innovative mechanical coupling designs, can form the basis for harvesting energy from mechanical motion. Piezoelectric energy can be harvested to convert walking motion from the human body into electrical power. Recently four proof-of-concept Heel Strike Units were developed where each unit is essentially

  2. Light Controlled Piezoelectric Transformer

    Microsoft Academic Search

    Lucjan Kozielski

    2011-01-01

    The author designed ``smart material'' device allow to control an output voltage level by change of incident light intensity. New functions of piezoelectric transformer (PT) was realized by superimposing piezoelectricity with photostriction. The effect of a light influence on the PT voltage gain was proved experimentally, consequently these ``smart'' transformers with its new functionality can be utilized as a promising

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

    SciTech Connect

    Schlattl, Helmut; Zankl, Maria; Eder, Heinrich; Hoeschen, Christoph [GSF-National Research Center for Environment and Health, Institute of Radiation Protection, Ingolstaedter Landstrasse 1, 85764 Neuherberg (Germany); Bavarian Environment Agency, Buergermeister-Ulrich-Strasse 160, 81679 Augsburg (Germany); GSF-National Research Center for Environment and Health, Institute of Radiation Protection, Ingolstaedter Landstrasse 1, 85764 Neuherberg (Germany)

    2007-11-15

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

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

    SciTech Connect

    Bhardwaj, Sumit, E-mail: sumit.bhardwaj4@gmail.com; Paul, Joginder, E-mail: sumit.bhardwaj4@gmail.com [Centre for Materials Science and Engineering, National Institute of Technology, Hamirpur -177 005 (India); Raina, K. K. [School of Physics and Materials Science, Thapar University, Patiala -147 004 (India); Thakur, N. S. [Centre for Energy and Environment, National Institute of Technology, Hamirpur -177005 (India); Kumar, Ravi [Centre for Materials Science and Engineering, National Institute of Technology, Hamirpur -177 005 (India); Beant College of Engineering and Technology, Gurdaspur -143521 (India)

    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.

  5. Inorganic ceramic\\/polymer ferroelectric composite electrets

    Microsoft Academic Search

    C. J. Dias; D. K. Das-Gupta

    1996-01-01

    Ferroelectric composites are now an established alternative to conventional ferroelectric ceramic materials and to the more recently discovered ferroelectric polymers. These materials due to their unique blending of polymetric properties of mechanical flexibility, formability and low cost with high electro-active properties have been been suggested to be a viable alternative both in piezoelectric and pyroelectric transducer applications. This review is

  6. 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.

  7. High-sensitivity piezoelectric perovskites for magnetoelectric composites

    NASA Astrophysics Data System (ADS)

    Amorn, Harvey; Alguer, Miguel; Del Campo, Rubn; Vila, Eladio; Ramos, Pablo; Doll, Mickael; Romaguera-Barcelay, Yonny; Prez De La Cruz, Javier; Castro, Alicia

    2015-02-01

    A highly topical set of perovskite oxides are high-sensitivity piezoelectric ones, among which Pb(Zr,Ti)O3 at the morphotropic phase boundary (MPB) between ferroelectric rhombohedral and tetragonal polymorphic phases is reckoned a case study. Piezoelectric ceramics are used in a wide range of mature, electromechanical transduction technologies like piezoelectric sensors, actuators and ultrasound generation, to name only a few examples, and more recently for demonstrating novel applications like magnetoelectric composites. In this case, piezoelectric perovskites are combined with magnetostrictive materials to provide magnetoelectricity as a product property of the piezoelectricity and piezomagnetism of the component phases. Interfaces play a key issue, for they control the mechanical coupling between the piezoresponsive phases. We present here main results of our investigation on the suitability of the high sensitivity MPB piezoelectric perovskite BiScO3PbTiO3 in combination with ferrimagnetic spinel oxides for magnetoelectric composites. Emphasis has been put on the processing at low temperature to control reactions and interdiffusion between the two oxides. The role of the grain size effects is extensively addressed.

  8. Piezoelectric properties of (Pb/sub 1-x/Ba/sub x/)/sub 2/NaNb/sub 5/O/sub 15/ ceramic under pressure along the polarization direction

    SciTech Connect

    Lopatin, S.S.; Medvedev, B.S.; Biyatenko, Yu.N.; Basenko, N.I.

    1987-02-01

    The authors use x-ray diffraction to study polarization and depolarization under a pressure of 380 MPa in the title ceramic where the value of x falls between 0.1 and 0.6. They establish that the irreversible and reversible changes in the piezomodulus, due to pressure along the direction of polarization, are determined by the phase composition of the ceramic. The greatest irreversible changes in the modulus are observed in the morphotropic region where x lies between 0.33 and 0.43, due to 90/sup 0/ disorientation of the phase domains with polar direction (010), and also to mutual transitions between coexistent phases.

  9. Experimental and numerical analysis of BGA lead-free solder joint reliability under board-level drop impact

    Microsoft Academic Search

    Fang Liu; Guang Meng; Mei Zhao; Jun feng Zhao

    2009-01-01

    Board-level solder joint reliability is very critical for handheld electronic products during drop impact. In this study, board-level drop test and finite element method (FEM) are adopted to investigate failure modes and failure mechanisms of lead-free solder joint under drop impact. In order to make all ball grid array (BGA) packages on the same test board subject to the uniform

  10. Development of lead-free metal fuel tank. Hot-dip aluminum coated steel sheet evaluations for fuel tank applications

    Microsoft Academic Search

    S. Choji; T. Sakauchi

    1999-01-01

    To prevent dissolved lead from draining into soil and underground water from the disposal of end of life vehicles (ELV) shredder residue, a lead-free vehicle development program has been initiated. As an alternative material to the present hot-dip lead-tin coated steel sheet (terne sheet), which has been in use for a long time, a hot-dip aluminum coated steel sheet was

  11. The properties of Sn9Zn lead-free solder alloys doped with trace rare earth elements

    Microsoft Academic Search

    C. M. L. Wu; D. Q. Yu; C. M. T. Law; L. Wang

    2002-01-01

    The Sn-Zn alloys have been considered as lead-free solders. It is well known that their poor properties of wetting and oxidation\\u000a resistance are the main problems to prevent them from becoming commercially viable solders. In this paper, trace rare earth\\u000a (RE) elements of mainly Ce and La have been used as alloying elements into the Sn-9Zn alloy. The results indicated

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

    Microsoft Academic Search

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

    2011-01-01

    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

  13. A systematic procedure for the selection of a lead-free solder paste in an electronics manufacturing environment

    Microsoft Academic Search

    Girish S. Wable; Quyen Chu; Purushothaman Damodaran; Krishnaswami Srihari

    2005-01-01

    Purpose Historically, tin-lead solder has been a commonly used joining material in electronics manufacturing. Environmental and health concerns, due to the leaching of lead from landfills into ground water, have necessitated legislation that restricts the use of lead in electronics. The transition from tin-lead solder to a lead-free solder composition is imminent. Several alternative solder alloys (and their fluxes)

  14. 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.

  15. Decomposition behavior and properties of Sn9Zn1Bi lead-free solder alloy with copper content

    Microsoft Academic Search

    M. Kamal; M. S. Mikhail; A. B. Bediwi; El Said Gouda

    2006-01-01

    Copper was chosen as quaternary additions in the range of 1-5 wt% to the ternary alloy Sn-9Zn-1Bi lead-free solder alloy. X-ray diffraction analysis, scanning electron microscopy and differential thermal analysis have been carried out. Resistivity, Vickers microhardness and yield strength have been measured. The results showed that formation of Cu-Sn intermetallic compounds takes place due to additions of Cu, which

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

    Microsoft Academic Search

    Brent Alan Fiedler

    2010-01-01

    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

  17. Decomposition behavior and properties of Sn9Zn1Bi lead-free solder alloy with copper content

    Microsoft Academic Search

    M. Kamal; M. S. Mikhail; A. B. Bediwi; El Said Gouda

    2006-01-01

    Copper was chosen as quaternary additions in the range of 15wt% to the ternary alloy Sn-9Zn-1Bi lead-free solder alloy. X-ray diffraction analysis, scanning electron microscopy and differential thermal analysis have been carried out. Resistivity, Vickers microhardness and yield strength have been measured. The results showed that formation of Cu-Sn intermetallic compounds takes place due to additions of Cu, which affected

  18. Modeling and characterization of electrostrictive ceramics

    NASA Astrophysics Data System (ADS)

    Sherrit, Stewart; Catoiu, Georgeta; Stimpson, Russell B.; Mukherjee, Benoy K.

    1998-07-01

    We present a non-linear theory for electromechanical materials based on a Taylor's series expansion of the thermodynamic potentials to 3rd and higher order terms in field and stress, and we show that this general theory is applicable to both piezoelectric and ideal electrostrictive materials depending with an appropriate choice of material coefficients. The model allows for the non-zero piezoelectric behavior found in some nominally electrostrictive materials. The quasistatic non-linear equations used to describe low frequency electromechanical devices are shown to account for saturation in both strain and polarization as well as the stress dependence. The `reversible' electrostrictive ceramic PMN/PT/La (0.9/0.1/1%) operating above Tmax is used to illustrate the suitability of the model. Under a DC bias field, these materials behave as a piezoelectric ceramic material with C?) symmetry. The effective piezoelectric is found to be linear as a function of the DC bias field up to about 0.5MV/m. Above 0.5 MV/m, the piezoelectric and the electromechanical coupling constants begin to saturate due to higher 4th order electrostriction (S ~ kE4 with k negative), which is shown to be the result of the saturation in the dielectric response. A switchable, low field, linear component of the piezoelectric voltage coefficient, g, is found in the S vs D response. The g coefficient is found to change sign depending on the sign of the measurement field. These materials behave as a tunable piezoelectric with the piezoelectric coefficient being directly proportional to the electrostrictive coefficient and the DC bias field, up to saturation.

  19. A very promising piezoelectric property of Ta 2O 5 thin films. II: Birefringence and piezoelectricity

    NASA Astrophysics Data System (ADS)

    Audier, M.; Chenevier, B.; Roussel, H.; Vincent, L.; Pea, A.; Lintanf Salan, A.

    2011-08-01

    Birefringent and piezoelectric properties of Ta 2O 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 2O 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 2O 5 of trigonal structure. From an estimation of the electrical field through the Ta 2O 5 thin film, this strain likely corresponds to a very high longitudinal coefficient d33 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).

  20. 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.

  1. Structural, ferroelectric, optical properties of A-site-modified Bi0.5(Na0.78K0.22)0.5Ti0.97Zr0.03O3 lead-free piezoceramics

    NASA Astrophysics Data System (ADS)

    Quan, N. D.; Quyet, N. V.; Bac, L. H.; Thiet, D. V.; Hung, V. N.; Dung, D. D.

    2015-02-01

    We reported the role of A-site modification on the structural, ferroelectric, optical and electrical field-induced strain properties of Bi0.5(Na0.78K0.22)0.5Ti0.97Zr0.03O3 lead-free piezoceramics. The Li+ ions with concentration from 0 to 5 mol% were used to substitute at A-site. There was no phase transition when Li+ ions was added up to 5 mol%. The electric field-induced strain (Smax/Emax) values increased from 600 to 643 pm/V for 2 mol% Li+-added which results from distortion both rhombohedral and tetragonal phase structures. The band gap reduced from 2.88 to 2.68 eV and the saturation polarization decreased from 46.2 to 26.1 ?C/cm2 when Li+ ions concentration increased from 0 to 5 mol% respectively. We expect that this work could be helpful for further understanding the role of A-site dopants in comparison with B-site modification in lead-free Bi0.5(Na,K)0.5TiO3-based ceramics.

  2. 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

    George, Steven C.

    : (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

  3. Lead free interfacial structures and their relationship to Au plating including accelerated thermal cycle testing of non-leaden BGA spheres

    Microsoft Academic Search

    Toshihiko Taguchi; Rikiya Kato; Satoru Akita; Atsushi Okuno; H. Suzuki; T. Okuno

    2001-01-01

    As lead is a harmful element, soldering in the electronics industry has moved toward elimination of lead from the solder alloy. Already there are a group of companies who have begun implementation of lead-free solder alloys. The scope of parts being tested for lead-free processes is not limited to the solder material; the complete absence of lead from electronics parts,

  4. Rayleigh analysis of dielectric properties in textured K0.5Na0.5NbO3 ceramics

    NASA Astrophysics Data System (ADS)

    Haugen, Astri Bjrnetun; Morozov, Maxim I.; Jones, Jacob L.; Einarsrud, Mari-Ann

    2014-12-01

    Grain texturing is a known method of exploiting the intrinsic dielectric and piezoelectric anisotropy in ferroelectric ceramics. However, the role of crystallographic texture on anisotropic extrinsic contributions including domain wall motion is not yet understood. Here, we investigate the dielectric and piezoelectric properties and small signal dielectric nonlinearities in K0.5Na0.5NbO3 ceramics in different directions of textured specimens and compare to ceramics without crystallographic texture. We demonstrate that directions in which pseudo-cubic <100> poles have greatest orientation density exhibit both an enhanced longitudinal piezoelectric response and lower dielectric nonlinearity.

  5. Piezoelectric cantilever acoustic transducer

    Microsoft Academic Search

    Seung S. Lee; Richard M. White

    1998-01-01

    We present a piezoelectric acoustic transducer fabricated on a bulk-micromachined cantilever diaphragm. Use of the cantilever as a supporting diaphragm produces a highly sensitive microphone. In addition, when the device is driven electrically as an output transducer, a microspeaker, the relatively large deflections produce significant acoustic output. A voltage-to-frequency converter has also been demonstrated with piezoelectric cantilever transducers. The 0960-1317\\/8\\/3\\/009\\/img5

  6. Piezoelectric cantilever acoustic transducer

    Microsoft Academic Search

    Seung S Leey; Richard M White

    1998-01-01

    We present a piezoelectric acoustic transducer fabricated on a bulk-micromachined cantilever diaphragm. Use of the cantilever as a supporting diaphragm produces a highly sensitive microphone. In addition, when the device is driven electrically as an output transducer, a microspeaker, the relatively large deflections produce significant acoustic output. A voltage-to-frequency converter has also been demonstrated with piezoelectric cantilever transducers. The 2

  7. 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.

  8. Photothermoacoustic oscillations in a solid-piezoelectric layered structure

    NASA Astrophysics Data System (ADS)

    Kozachenko, V. V.; Kucherov, I. Ya.

    2004-03-01

    Photothermoacoustic oscillations in a thin plane-layered structure consisting of an isotropic solid and a piezoelectric crystal of class 6 mm (or piezoelectric ceramics) are studied theoretically and experimentally. Expressions for the potential difference across an arbitrary layer of the piezoelectric transducer are derived. For the case of a two-layer transducer, the amplitude-frequency and phase-frequency dependences of the signal are analyzed. It is shown that, from these experimental dependences, one can determine certain elastic and thermal parameters of a solid. An experiment is performed with samples of Cu, Zn, and TsTS-19 piezoceramics in the frequency range within 9 1000 Hz. The experimental data are used to determine the values of the reduced Youngs modulus and the thermal diffusivity of the materials under study.

  9. 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.

  10. Domain-size dependence of piezoelectric properties of ferroelectrics

    NASA Astrophysics Data System (ADS)

    Ahluwalia, Rajeev; Lookman, Turab; Saxena, Avadh; Cao, Wenwu

    2005-07-01

    The domain-size dependence of the piezoelectric properties of ferroelectrics is investigated using a continuum Ginzburg-Landau model that incorporates long-range elastic and electrostatic interactions. Microstructures with the desired domain sizes are created by quenching from the paraelectric phase by biasing the initial conditions. Three different two-dimensional microstructures with different sizes of the 90 domains are simulated. An electric field is applied along the polar as well as nonpolar directions and the piezoelectric response is simulated as a function of domain size for both cases. The simulations show that the piezoelectric coefficients are enhanced by reducing the domain size, consistent with recent experimental results of Wada and Tsurumi [Br. Ceram. Trans. 103, 93 (2004)] on domain-engineered BaTiO3 single crystals.

  11. Domain Size Dependence of Piezoelectric Properties of Ferroelectrics

    NASA Astrophysics Data System (ADS)

    Saxena, Avadh; Cao, Wenwu

    2005-03-01

    The domain size dependence of piezoelectric properties of ferroelectrics is investigated using a continuum Ginzburg-Landau model that incorporates the long-range elastic and electrostatic interactions. Microstructures with desired domain sizes are created by quenching from the paraelectric phase by biasing the initial conditions. Three different two-dimensional microstructures with different sizes of the 90^o domains are simulated. An electric field is applied along the polar as well as non-polar directions and the piezoelectric response is simulated as a function of domain size for both cases. The simulations show that the piezoelectric coefficients are enhanced by reducing the domain size, consistent with recent experimental results of Wada and Tsurumi (Brit. Ceram. Trans. 103, 93, 2004) on domain engineered BaTiO3 single crystals.

  12. Phase diagram and enhanced piezoelectricity in the strontium titanate doped potassium-sodium niobate solid solution

    Microsoft Academic Search

    Ruiping Wang; Rong-Jun Xie; Kotaro Hanada; Kunio Matsusaki; Hiroshi Bando; Mitsuru Itoh

    2005-01-01

    The dielectric and the piezoelectric properties of the (1-x)(Na0.5K0.5)NbO3-xSrTiO3 ceramics, densified by the Spark-Plasma-Sintering method, have been studied. A phase diagram was established from the temperature dependence of the dielectric constant. A tetragonal-orthorhombic morpho-tropic phase boundary (MPB) was found at x 0.05. Around the MPB, piezoelectric properties were greatly improved. The origin for the enhanced piezoelectricity has been proposed.

  13. 3D Piezoelectric Structures Made by Ink-Jet Printing

    Microsoft Academic Search

    Gautier Senlis; Matthieu Dubarry; Martine Lejeune; Thierry Chartier

    2002-01-01

    The purpose of this paper is to report the potential interest to develop piezoelectric structures by taking advantage both of the adaptive electromechanical behavior of 0.9PbMg 1\\/3 Nb 2\\/3 O 3 (PMN)-0.1PbTiO 3 (PT) ceramics and of the characteristics of rapid prototyping methods. In fact, as the piezo-activity of 0.9PMN-0.1PT ceramics is adjustable via the amplitude of the electric field;

  14. 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

  15. Energy Harvesting Using a Piezoelectric ``Cymbal'' Transducer in Dynamic Environment

    Microsoft Academic Search

    Hyeoung Woo Kim; Amit Batra; Shashank Priya; Kenji Uchino; Douglas Markley; Robert E. Newnham; Heath F. Hofmann

    2004-01-01

    In this study, we investigated the capability of harvesting the electrical energy from mechanical vibrations in a dynamic environment through a ``cymbal'' piezoelectric transducer. Targeted mechanical vibrations lie in the range of 50-150 Hz with force amplitude in the order of 1 kN (automobile engine vibration level). It was found that under such severe stress conditions the metal-ceramic composite transducer

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

    Microsoft Academic Search

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

    2011-01-01

    To evaluate the current leakage and electrochemical migration behavior on printed circuit boards with eutectic tin-lead and\\u000a lead-free solder, IPC B-24 comb structures were exposed to 65C and 88% relative humidity conditions under direct-current\\u000a (DC) bias for over 1500h. These boards were processed with either Sn-3.0Ag-0.5Cu solder or Sn-37Pb solder. In addition to\\u000a solder alloy, board finish (organic solderability preservative

  17. Contact angle measurements of SnAg and Sn-Cu lead-free solders on copper substrates

    Microsoft Academic Search

    Mario F. Arenas; Viola L. Acoff

    2004-01-01

    In this study, the contact angles of four lead-free solders, namely, Sn-3.5Ag, Sn-3.5Ag-4.8Bi, Sn-3.8Ag-0.7Cu, and Sn-0.7Cu (wt.%), were measured on copper substrates at different temperatures. Measurements were performed using the sessile-drop method. Contact angles ranging from 30 to 40 after wetting under vacuum with no fluxes and between 10 and 30 with rosin mildly activated (RMA) and rosin activated (RA)

  18. Contact angle measurements of SnAg and Sn-Cu lead-free solders on copper substrates

    Microsoft Academic Search

    Mario F. Arenas; Viola L. Acoff

    2004-01-01

    In this study, the contact angles of four lead-free solders, namely, Sn-3.5Ag, Sn-3.5Ag-4.8Bi, Sn-3.8Ag-0.7Cu, and Sn-0.7Cu\\u000a (wt.%), were measured on copper substrates at different temperatures. Measurements were performed using the sessile-drop method.\\u000a Contact angles ranging from 30 to 40 after wetting under vacuum with no fluxes and between 10 and 30 with rosin mildly\\u000a activated (RMA) and rosin activated (RA)

  19. 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.

  20. Enhanced mechanical properties in Ag-particle-dispersed PZT piezoelectric composites for actuator applications

    Microsoft Academic Search

    H. L. Zhang; J.-F. Li; B.-P. Zhang; W. Jiang

    2008-01-01

    Functional ceramics naturally have inferior mechanical properties. This study shows that incorporating Ag into lead zirconate titanate (PZT) piezoelectric ceramics by co-firing in air at 1200C is effective for mechanical property enhancement. The Ag addition has increased the fracture strength ?f from 69MPa for monolithic PZT to 129MPa for PZT15% Ag composite, and increased the corresponding fracture toughness KIC from

  1. 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

  2. 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.

  3. Piezoelectric hydraulic pump performance

    NASA Astrophysics Data System (ADS)

    Mauck, Lisa D.; Oates, William S.; Lynch, Christopher S.

    2001-06-01

    A piezohydraulic pump making use of the step and repeat capability of piezoelectric actuators has been developed for actuation of aircraft control surfaces. The piezohydraulic pump utilizes a piezoelectric stack actuator to drive a piston in a cylinder. The cylinder is fitted with two check valves. On the compression stroke, oil is forced out of the cylinder. On the intake stroke, oil is drawn into the cylinder. The oil is used to drive a linear actuator. The actuator was driven at 7cm/sec with a 271N (61lb) blocking force. To achieve this, the piezoelectric stack actuator was driven at 60Hz with a switching power supply. The system utilizes an accumulator to eliminate cavitation. This work discusses piezohydraulic pumping theory, pump design, and pump performance. Consideration of pump performance includes the effects of varying accumulator pressure, hydraulic oil viscosity, and load imposed on the linear actuator.

  4. Piezoelectric wave motor

    DOEpatents

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

    2003-02-11

    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 the 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.

  5. Enhanced active piezoelectric 0-3 nanocomposites fabricated through electrospun nanowires

    NASA Astrophysics Data System (ADS)

    Feenstra, Joel; Sodano, Henry A.

    2008-06-01

    The use of monolithic piezoceramic materials in sensing and actuation applications has become quite common over the past decade. However, these materials have several properties that limit their application in practical systems. These materials are very brittle due to the ceramic nature of the monolithic material, making them vulnerable to accidental breakage during handling and bonding procedures. In addition, they have very poor ability to conform to curved surfaces and result in large add-on mass associated with using a typically lead-based ceramic. These limitations have motivated the development of alternative methods of applying the piezoceramic material, including piezoceramic fiber composites and piezoelectric 0-3 composites (also known as piezoelectric paint). Piezoelectric paint is desirable because it can be spayed or painted on and can be used with abnormal surfaces. However, the piezoelectric paint developed in prior studies has resulted in low coupling, limiting its application. In order to increase the coupling of the piezoelectric paint, this effort has investigated the use of piezoelectric nanowires rather than spherical piezoelectric particle, which are difficult to strain when embedded in a polymer matrix. The piezoceramic wires were electrospun from a barium titanate (BaTiO3) sol gel to produce fibers with 500-1000nm diameters and subsequently calcinated to acquire perovskite BaTiO3. An active nanocomposite paint was formed using the resulting piezoelectric wires and was compared to the same paint with piezoelectric nanoparticles. The results show that the piezoceramic wires produce 0-3 nanocomposites with as high as 300% increase in electromechanical coupling.

  6. Effect of porosity on dielectric properties and microstructure of porous PZT ceramics

    Microsoft Academic Search

    B. Praveen Kumar; H. H. Kumar; D. K. Kharat

    2006-01-01

    Porous piezoelectric materials are of great interest because of their high hydrostatic figure of merit and low sound velocity, which results in to low acoustic impedance and efficient coupling with medium. Porous lead zirconate titanate (PZT) ceramics with varying porosity was developed using polymethyl methacrylate by burnable plastic spheres (BURPS) process. The porous PZT ceramics were characterized for dielectric constant

  7. Composite ceramic-metal plates tested with flexural waves and holography

    Microsoft Academic Search

    M. Conrad; M. Sayir

    2001-01-01

    A method to determine weak or defective bonding areas within the brazed adjoining contact surfaces of composite ceramic-metal plates is proposed. The plates include voids, as well as hairline cracks in the ceramic layer, caused by the high-temperature brazing process. To detect these flaws, transient flexural waves are generated and transmitted through the plate by means of an attached piezoelectric

  8. 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

  9. 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.

  10. Comparison of actuator properties for piezoelectric and electrostrictive materials

    NASA Astrophysics Data System (ADS)

    Pan, Ming-Jen; Rehrig, Paul W.; Kucera, John P.; Park, Seung Eek E.; Hackenberger, Wesley S.

    2000-06-01

    The field induced strain has been measured for a broad variety of piezoelectric and electrostrictive actuator materials. These measurements have been made under AC drive conditions with variations in DC bias, peak to peak voltage, and prestress. Data for three types of PMN-PT electrostrictors, hard and soft piezoelectric ceramics, and PZN-PT single crystal have been collected. For smart structures applications fine grain Type II ceramic and PZN- PT single crystals were found to have the best combination of moderate to high strain, low to moderate hysteresis, and resistance to stress depoling. Electrostrictive ceramics used for high frequency transducers were found to exhibit some stress induced domain reorientation effects that depended on drive conditions and operating temperature. These effects became more pronounced for electrostrictors with high lead titanate content. Epoxy bonded stacks have been constructed form some of the materials to determine the merits of materials properties for actuator performance. This work has shown that fine grain Type II ceramics have many advantages for high authority stack actuators including high strain energy density and lifetimes > 109 cycles at 100 percent rated peak-to-peak voltage.

  11. 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 ...

  12. Solder Joint Characteristics and Reliability of Lead-Free Area Array Packages Assembled Under Various Tin-Lead Soldering Process Conditions

    Microsoft Academic Search

    Jennifer Nguyen; D. Geiger; D. Rooney; Dongkai Shangguan

    2007-01-01

    The compatibility of lead-free area array packages with tin-lead soldering processes is a critical issue, as several product categories may take advantage of the exemptions under the European Union (EU) RoHS legislation and continue to be built with tin-lead solder for some time to come, whereas the components have become predominantly lead-free. The issue of \\

  13. Journal of ELECTRONIC MATERIALS, Vol. 33, No. 12, 2004 Special Issue Paper Intermetallic Phase Detection in Lead-Free Solders Using

    E-print Network

    Ekere, Ndy

    Detection in Lead-Free Solders Using Synchrotron X-Ray Diffraction GAVIN J. JACKSON,1 HUA LU,2,6 RAJ-ray diffraction (XRD) experiments to detect intermetallic compounds (IMCs) in lead-free solder bumps. The IMCs found in 95.5Sn3.8Ag0.7Cu solder bumps on Cu pads with electroplated-nickel immersion-gold (ENIG

  14. Muscular PiezoElectricity?

    Microsoft Academic Search

    F. Buchanan

    1921-01-01

    THE well-known ``action current'' of muscle can have nothing to do with piezo-electricity, since it may reach its maximum before any mechanical change begins. Nor do I see anything to suggest the occurrence of such electricity in other animal tissues or organs. Mr. Wriothesley Russell (NATURE, October 27, p. 275) might, however, find plants worth investigating for evidence of it.

  15. Characterization of dissipation factors in terms of piezoelectric equivalent circuit parameters.

    PubMed

    Chen, Yu; Wen, Yumei; Li, Ping

    2006-12-01

    The equivalent circuit of a piezoelectric ceramic is established composed of the equivalent circuit parameters derived from the complex materials coefficients. The equivalent circuit parameters are connected to real and imaginary parts of the complex materials coefficients of the piezoelectric ceramics. With respect to the definition of dissipation factors, the dielectric, elastic, and piezoelectric dissipation factors which represent the losses in the materials are thus expressed through the equivalent circuit parameters. In temperature and stress experiments, by measuring the equivalent circuit parameters during the process of the temperature and stress changes, three dissipation factors are computed. Compared with the results of other previous research, a similar increase of the elastic dissipation factor with stress is observed. Moreover, it is also found that the elastic dissipation factor reaches its saturation over a stress level of about 10 MPa. The responses of dissipation factors in lower temperature (-30 degrees C to 20 degrees C) are studied. PMID:17186919

  16. Electric field induced short range to long range structural ordering and its influence on the Eu+3 photoluminescence in the lead-free ferroelectric Na1/2Bi1/2TiO3

    NASA Astrophysics Data System (ADS)

    Kalaskar, Abhijeet; Rao, Badari Narayana; Thomas, Tiju; Ranjan, Rajeev

    2015-06-01

    Eu+3 was incorporated into the lattice of a lead-free ferroelectric Na1/2Bi1/2TiO3 (NBT) as per the nominal formula Na0.5Bi0.5-xEuxTiO3. This system was investigated with regard to the Eu+3 photoluminescence (PL) and structural behaviour as a function of composition and electric field. Electric field was found to irreversibly change the features in the PL spectra and also in the x-ray diffraction patterns below the critical composition x = 0.025. Detailed analysis revealed that below the critical composition, electric field irreversibly suppresses the structural heterogeneity inherent of the host matrix NBT and brings about a long range ferroelectric state with rhombohedral (R3c) distortion. It is shown that the structural disorder on the nano-scale opens a new channel for radiative transition which manifests as a new emission line branching off from the main 5D0?7F0 line along with a concomitant change in the relative intensity of the other crystal field induced Stark lines with different J values. The study suggests that Eu+3 luminescence can be used to probe the relative degree of field induced structural ordering in relaxor ferroelectrics and also in high performance piezoelectric alloys where electric field couples very strongly with the lattice and structural degrees of freedom.

  17. 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

  18. 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.

  19. 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.

  20. Temperature dependence of elastic properties and piezoelectric applications of BaTeMo2O9 single crystal.

    PubMed

    Gao, Zeliang; Yin, Xin; Zhang, Weiguo; Wang, Shanpeng; Jiang, Minhua; Tao, Xutang

    2011-12-01

    BaTeMo(2)O(9) (BTM) single crystal, as a lead-free piezoelectric material, belongs to the monoclinic system, space group P2(1). We report the temperature dependence of the elastic constants by the transmission method over the range -50C to 150C. The first-order temperature coefficients of the elastic constant s(44) is about 180 10(-6)/C. Piezoelectric resonators based on BTM crystal using the thickness-stretching vibration and the shear vibration modes were designed and evaluated, which eliminated or minimized the influence of the off-principal axis coefficients. The Q(m) of one of the resonators is about 600. Our results show that the elastic constants have good temperature stability, and the resonators have already met the requirements for some piezoelectric applications. This study on the BTM crystal has revealed the application for the low-symmetry crystal. PMID:23443712

  1. 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.

  2. Manufacturing of prestressed piezoelectric unimorphs using a postfired biasing layer.

    PubMed

    Juuti, Jari A; Jantunen, Heli; Moilanen, Veli-Pekka; Leppvuori, Seppo

    2006-05-01

    A novel manufacturing method for prestressed piezoelectric unimorphs is introduced and the actuator properties are examined. Prestressed PZT 5A and PZT 5H unimorphs with piezo material thickness of 250 microm and 375 microm were manufactured by using sintering and thermal shrinkage of the prestressing material. The process was carried out by screen printing a layer of AgPd paste on one side of the sintered bulk ceramic. As an alternative method, dielectric low temperature co-fired ceramic (LTCC) tape was used as the prestressing material. Different configurations were tested to obtain high displacements and to make a comparison between materials. After firing, the samples were poled, and the displacement versus load characteristics of the resulting actuators were investigated. A maximum displacement of 118 microm was obtained from a 250 microm thick, prestressed PZT 5H actuator with a diameter of 25 mm, in which LTCC tape was used as the prestressing layer. Similarly, the PZT 5H material provided a maximum displacement of 63 microm with a screen-printed AgPd prestressing layer. The manufacturing method described offers a novel approach for the production of a wide range of integrated active structures on, for instance, an LTCC circuit board. This is especially important because piezoelectric bulk materials with high piezoelectric coefficients can be used to produce high displacements. PMID:16764438

  3. Ceramic filters

    SciTech Connect

    Holmes, B.L.; Janney, M.A.

    1995-12-31

    Filters were formed from ceramic fibers, organic fibers, and a ceramic bond phase using a papermaking technique. The distribution of particulate ceramic bond phase was determined using a model silicon carbide system. As the ceramic fiber increased in length and diameter the distance between particles decreased. The calculated number of particles per area showed good agreement with the observed value. After firing, the papers were characterized using a biaxial load test. The strength of papers was proportional to the amount of bond phase included in the paper. All samples exhibited strain-tolerant behavior.

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

    SciTech Connect

    Audier, M., E-mail: Marc.Audier@grenoble-inp.fr [Laboratoire des Materiaux et du Genie Physique, UMR CNRS 5628, Minatec - INP Grenoble, 3 parvis Louis Neel, BP 257, 38016 Grenoble Cedex 1 (France); Chenevier, B.; Roussel, H. [Laboratoire des Materiaux et du Genie Physique, UMR CNRS 5628, Minatec - INP Grenoble, 3 parvis Louis Neel, BP 257, 38016 Grenoble Cedex 1 (France); Vincent, L. [CIME Nanotech Minatec, Microsystemes et capteurs, F-38016 Grenoble Cedex 1 (France); Pena, A. [Institut Neel - CNRS/UJF, Dpt. Matiere Condensee, Materiaux et Fonctions, F-38042 Grenoble (France); Lintanf Salauen, A. [L2MA, CEA LETI D2NT, F-38054 Grenoble (France)

    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.

  5. 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.

  6. Effect of electric fields on fracture behavior of ferroelectric ceramics

    Microsoft Academic Search

    H. G Beom; S. N Atluri

    2003-01-01

    The asymptotic problem of a semi-infinite crack perpendicular to the poling direction in a ferroelectric ceramic subjected to combined electric and mechanical loading is analyzed to investigate effect of electric fields on fracture behavior. Electromechanical coupling induced by the piezoelectric effect is neglected in this paper. The shape and size of the switching zone is shown to depend strongly on

  7. Influence of electric fields on the fracture of ferroelectric ceramics

    Microsoft Academic Search

    Andreas Ricoeur; Meinhard Kuna

    2003-01-01

    This paper deals with the fracture mechanics of piezoelectric solids. All investigations consider a single crack, which is exposed to combined electrical and mechanical loading. The main subject of interest is the influence of electric fields on the fracture toughness of ferroelectric ceramics and the derivation of an appropriate fracture criterion. Numerical techniques are presented, allowing for the calculation of

  8. Oxide materials for electronics Inorganic Materials and Ceramics Research Group

    E-print Network

    spray pyrolysis Ceramic processing and coating technology Pressing, tape casting, extrusion Spray (ferroelectricity) NTNU NanoLab NORTEM #12;In situ X-ray diffraction In situ T, atmosphere, up to 20 bar pressure the anisotropic nature of piezoelectricity: Ba0.92Ca0.08TiO3 textured by tape casting with templates. Haugen et al

  9. Measurements of the thermal, dielectric, piezoelectric, pyroelectric and elastic properties of porous PZT samples

    NASA Astrophysics Data System (ADS)

    Lang, Sidney B.; Ringgaard, Erling

    2012-06-01

    The introduction of porosity into ferroelectric ceramics has been of great interest in recent years. In particular, studies of porous lead-zirconate-titanate ceramic (PZT) have been made. In the research reported, samples of Ferroperm Pz27 with porosities of 20, 25 and 30% were studied. Very complete measurements were made of all of the physical properties relevant for ferroelectric applications including thermal conductivity and diffusivity, heat capacity, dielectric, pyroelectric, piezoelectric and elastic properties. Scanning electron micrographs indicated a change from 3-0 to 3-3 connectivity with increasing porosity. Although most of the physical properties are degraded by the presence of porosity, both piezoelectric and pyroelectric figures-of-merit are improved because of the markedly reduced relative permittivity. Porous ferroelectric ceramics are very promising materials for a number of applications.

  10. Piezoelectricity in protein amino acids

    NASA Astrophysics Data System (ADS)

    Lemanov, V. V.; Popov, S. N.; Pankova, G. A.

    2011-06-01

    The piezoelectric activity of protein amino acids and their compounds has been measured using the pulse method at a frequency of 10 MHz. It has been established that, at room temperature, the piezoelectric effect is not observed in ?-glycine (achiral amino acid) and protein amino acids of the L modification, namely, methionine, phenylalanine, and tryptophan. An assumption has been made that this phenomenon is associated with the enhanced damping of elastic vibrations excited in samples due to the piezoelectric effect.

  11. Micromachined Piezoelectric Cantilever Transducers

    Microsoft Academic Search

    Seung Seob Lee

    1995-01-01

    In this thesis, we present a micromachined piezoelectric acoustic transducer fabricated on a cantilever. Use of the cantilever as a supporting diaphragm produces a highly sensitive microphone. In addition, when the device is driven electrically as an output transducer (microspeaker), the relatively large deflections produce significant acoustic output. A voltage-to-frequency converter and a self-excited oscillator have also been demonstrated with

  12. Piezoelectrically actuated tunable capacitor

    Microsoft Academic Search

    Chuang-Yuan Lee; Eun Sok Kim

    2006-01-01

    This paper describes the design, fabrication, and characterization of the first MEMS piezoelectric tunable capacitors employing zinc oxide (ZnO) actuation. Relatively simple design rules for the device-structure optimization for largest deflection are shown from simulation results based on theoretical equations. The ZnO-actuated tunable capacitors are accordingly designed and fabricated with both surface and bulk micromachining techniques. Through the surface micromachining

  13. Piezoelectricity in indium nitride

    Microsoft Academic Search

    I. L Guy; Z Zheng; M Wintrebert-Fouquet; K. S. A Butcher; P Chen; T. L Tansley

    2004-01-01

    An interferometric method has been used to measure the piezoelectric coefficient d33 in thin, InN layers grown by remote plasma-enhanced chemical vapour deposition. The measured value of the coefficient varies from around 3.1 to 4.7pmV?1. Theoretical predictions for these coefficients are scarce, but these values are significantly lower than those which are available. The discrepancy arises largely from the clamping

  14. Piezoelectrically enhanced photocathode

    NASA Technical Reports Server (NTRS)

    Beach, Robert A. (Inventor); Nikzad, Shouleh (Inventor); Strittmatter, Robert P. (Inventor); Bell, Lloyd Douglas (Inventor)

    2009-01-01

    A photocathode, for generating electrons in response to incident photons in a photodetector, includes a base layer having a first lattice structure and an active layer having a second lattice structure and epitaxially formed on the base layer, the first and second lattice structures being sufficiently different to create a strain in the active layer with a corresponding piezoelectrically induced polarization field in the active layer, the active layer having a band gap energy corresponding to a desired photon energy.

  15. Black branes as piezoelectrics.

    PubMed

    Armas, Jay; Gath, Jakob; Obers, Niels A

    2012-12-14

    We find a realization of linear electroelasticity theory in gravitational physics by uncovering a new response coefficient of charged black branes, exhibiting their piezoelectric behavior. Taking charged dilatonic black strings as an example and using the blackfold approach we measure their elastic and piezolectric moduli. We also use our results to draw predictions about the equilibrium condition of charged dilatonic black rings in dimensions higher than six. PMID:23368298

  16. Size-dependent piezoelectricity

    E-print Network

    Ali R. Hadjesfandiari

    2012-06-28

    In this paper, a consistent theory is developed for size-dependent piezoelectricity in dielectric solids. This theory shows that electric polarization can be generated as the result of coupling to the mean curvature tensor, unlike previous flexoelectric theories that postulate such couplings with other forms of curvature and more general strain gradient terms ignoring the possible couple- stresses. The present formulation represents an extension of recent work that establishes a consistent size-dependent theory for solid mechanics. Here by including scale-dependent measures in the energy equation, the general expressions for force- and couple-stresses, as well as electric displacement, are obtained. Next, the constitutive relations, displacement formulations, the uniqueness theorem and the reciprocal theorem for the corresponding linear small deformation size-dependent piezoelectricity are developed. As with existing flexoelectric formulations, one finds that the piezoelectric effect can also exist in isotropic materials, although in the present theory the coupling is strictly through the skew-symmetric mean curvature tensor. In the last portion of the paper, this isotropic case is considered in detail by developing the corresponding boundary value problem for two dimensional analyses and obtaining a closed form solution for an isotropic dielectric cylinder.

  17. 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...

  18. The piezoelectric response of nanotwinned BaTiO3

    NASA Astrophysics Data System (ADS)

    Hlinka, J.; Ondrejkovic, P.; Marton, P.

    2009-03-01

    The piezoelectric properties of tetragonal BaTiO3 crystals with a very high density of 90 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.

  19. (Na, Bi)TiO3 based lead-free ferroelectric thin films on Si substrate for pyroelectric infrared sensors

    NASA Astrophysics Data System (ADS)

    Akai, D.; Yoshita, R.; Ishida, M.

    2013-04-01

    In this study, we report ferroelectric and pyroelectric properties of (Na0.5Bi0.5)TiO3-BaTiO3 (NBT-BT) thin films on Si substrates using chemical solution deposition for the first time. The NBT-BT thin films deposited on Pt/Ti/SiO2/Si substrates have exhibited a typical hysteresis loop with remnant polarization of 5 ?C/cm2 and coercive field of 80 kV/cm. Furthermore NBT-BT films showed pyroelectricity with pyroelectric coefficient of 0.610-8 C/cm2K. Monolithic-integration of Si electronics and lead-free ferroelectric NBT thin films has been archived using SiN passivation layer. It was previously believed that LSI processes could not incorporate any sodium-containing material which would cause characteristic degradation, such as threshold voltage shift. In this work, no threshold voltage shift in MOS characteristics was observed using this SiN layer. The SiN layer not only blocked diffusion from NBT chemistry, but also from crystallized NBT films during NBT formation process.

  20. Effects of Cu, Zn on the Wettability and Shear Mechanical Properties of Sn-Bi-Based Lead-Free Solders

    NASA Astrophysics Data System (ADS)

    Shen, Jun; Pu, Yayun; Yin, Henggang; Tang, Qin

    2015-01-01

    Effects of minor Cu, Zn additions on the wettability, microstructures, and shear properties of Sn-Bi-based lead-free solder joints were investigated. The results show that a Cu addition promotes the wetting ratio of solder alloy, while Zn creates the opposite effect. The Cu5Zn8 intermetallic compound layer at the interface of Sn-40Bi-2Zn-0.1Cu and the Cu substrate alters the surface tension, which increases the contact angle. Also, this type of intermetallic compound contributes to the change of three wetting indicators. A proper amount of Cu, Zn increased the wetting force and decreased the wetting time, while the variation in the trend of withdrawing force is consistent with that of contact angle. From joint shear test results, the shear force decreased in the following order: Sn-40Bi-0.1Cu, Sn-58Bi, and Sn-40Bi-2Zn-0.1Cu solder joints. Cu additions refined the grain size of the Bi-rich phase and decreased the interface brittleness, which is the reason for the improvement of the shear strength of Sn-40Bi-0.1Cu solder joints. In contrast, Zn weakened the shear strength due to the brittle nature of the Zn-rich phase and the chemical activity of Zn.