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1

Current Developments and Prospective of Lead-Free Piezoelectric Ceramics  

Microsoft Academic Search

The dielectric, ferroelectric and piezoelectric properties of perovskite ferroelectric and bismuth layered-structured ferroelectric (BLSF) ceramics are described being superior candidates for lead-free piezoelectric materials to reduce environmental damage. Perovskite-type ceramics seem to be suitable for actuator and high-power applications that require a large piezoelectric constant, d33, and a high Curie temperature, Tc, or a depolarization temperature, Td (>200 °C). For

Tadashi Takenaka; Hajime Nagata; Yuji Hiruma

2008-01-01

2

Current status and prospects of lead-free piezoelectric ceramics  

Microsoft Academic Search

Dielectric, ferroelectric and piezoelectric properties of perovskite ferroelectric and bismuth layer-structured ferroelectric (BLSF) ceramics are described as superior candidates for lead-free piezoelectric materials to reduce environmental damages. Perovskite type ceramics seem to be suitable for actuator and high power applications that are required a large piezoelectric constant, d33 (>300pC\\/N) and a high Curie temperature, Tc (>200°C). For BaTiO3 (BT)-based solid

Tadashi Takenaka; Hajime Nagata

2005-01-01

3

Current Developments and Prospective of Lead-Free Piezoelectric Ceramics  

NASA Astrophysics Data System (ADS)

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

Takenaka, Tadashi; Nagata, Hajime; Hiruma, Yuji

2008-05-01

4

KNN-NTK composite lead-free piezoelectric ceramic  

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

5

New method for fabrication of lead-free BaTiO3 piezoelectric ceramics  

Microsoft Academic Search

BaTiO3 (BT) powders were synthesized by hydrothermal method for fabricating lead-free barium titanate piezoelectric ceramics. The effect of the two washing methods (distilled water and acetic acid solutions) on the piezoelectric properties of the BT ceramics was studied. BT ceramics with the higher piezoelectric properties (d33 value is over 190 pC\\/N) was obtained from the powders washed by acetic acid

Kong-jun Zhu; Li-kui Su; Hong-li Ji; Jin-hao Qiu

2008-01-01

6

Shear-Mode Industrial Inkjet Head Using Lead-Free Piezoelectric Ceramics  

NASA Astrophysics Data System (ADS)

A shear-mode inkjet head utilizing alkaline niobate-based lead-free piezoelectric ceramics has been developed. A prototype inkjet head with a nozzle density 150 dots per inch (dpi) was achieved on a grayscale of eight levels with a minimum ink droplet ejection of 6 pl. Furthermore, the inkjet head with a nozzle density of 300 dpi was achieved on a grayscale of four levels with a minimum ink droplet ejection of 3 pl. Although the prototype inkjet head required a high voltage of approximately twice the driving voltage of the inkjet head using lead zirconate titanate (PZT) piezoelectric ceramics, the grayscale can be realized by a multidrop method. Thus, the alkaline niobate-based lead-free piezoelectric ceramics can be used to replace PZT ceramics as shear-mode actuators for inkjet heads.

Tanuma, Chiaki; Shimosato, Masashi; Nitta, Noboru; Yamamoto, Keizaburou; Takahashi, Hirofumi

2012-09-01

7

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

NASA Astrophysics Data System (ADS)

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.

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

2015-03-01

8

Influence of calcined temperature and sintered technology on the properties of NBT-KBT-BT lead-free piezoelectric ceramics  

Microsoft Academic Search

The influence of calcined temperature and sintered technology on the properties of 0.85 (Na0.5Bi0.5) TiO3–0.144(K0.5Bi0.5)TiO3–0.006BaTiO3(NBT-KBT-BT) lead-free piezoelectric ceramics was investigated by conventional solid state method, and the relationship between calcined temperature, sintered technology and properties of NBT-KBT-BT lead-free piezoelectric ceramics was obtained. The influence of calcined temperature on the material phase was investigated by X-ray diffraction(XRD), the influence of sintered

Xin-you Huang; Chun-hua Gao; Zhi-gang Chen

2011-01-01

9

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

SciTech Connect

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.

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 Universität Darmstadt, Alarich-Weiss-Straße 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

10

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

NASA Astrophysics Data System (ADS)

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.

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

2014-03-01

11

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

NASA Astrophysics Data System (ADS)

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

Leontsev, Serhiy

12

Bi4Ti3O12-based lead-free piezoelectric ceramics with grain orientation  

Microsoft Academic Search

Piezoelectric properties of Bi4Ti3-xNbxO12 [BITN-x] and B4Ti3-xVxO12 [BITV-x] ceramics are investigated. Furthermore, grain orientation effects of BITN and BITV ceramics on their piezoelectric properties are studied using the hot-forging (HF) method. The optimal sintering temperature of the BITV ceramic becomes lower with increasing the amount of doped-V ions. On the ordinarily fired (OF) sample with a random orientation, an electromechanical

H. Nagata; Y. Fujita; H. Enosawa; T. Takenaka

2002-01-01

13

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

E-print Network

Microstructure Design of Lead-Free Piezoelectric Ceramics S.-B. Lee, T. S. Key, Z. Liang, R. E-Free Piezoelectrics 2 #12;1 Introduction Recent advances in performance of lead-free piezoelectric ceramics haveC/N [11,12], suggesting further room for improvement. Historically, the effect of microstructure has been

Rohrer, Gregory S.

14

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

E-print Network

.04)O3 (KNL-NTS) were successfully fabricated by traditional ceramics processing. The effects, pure KNN ceramics are difficult to fully densify by ordinary sintering methods due to the high been widely used to prepare KNN-based ceramics by conventional solid state sintering methods [7

Volinsky, Alex A.

15

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

E-print Network

ferroelectric ceramics G. R. Li & Q. R. Yin & L. Y. Zheng Y. Y. Guo & W. W. Cao Published online: 17 May 2007 curves of LNN ceramics showed that there exist three phase transitions from room temperature up. The solid solution NaxLi1-xNbO3 (LNN) ceramics is a very interest- ing material due to its lead free

Cao, Wenwu

16

Lead-free multilayer piezoelectric transformer  

NASA Astrophysics Data System (ADS)

In this article, a multilayer piezoelectric transformer based on lead-free Mn-doped 0.94(Bi1/2Na1/2)TiO3-0.06BaTiO3 ceramics is presented. This piezoelectric transformer, with a multilayered construction in the thickness direction, is 8.3mm long, 8.3mm wide, and 2.3mm thick. It operates in the second thickness extensional vibration mode. For a temperature rise of 20°C, the transformer has an output power of >0.3W. With a matching load resistance of 10?, its maximum efficiency approaches 81.5%, and the maximum voltage gain is 0.14. It has potential to be used in low voltage power supply units such as low power adapter and other electronic circuits.

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

2007-01-01

17

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

NASA Astrophysics Data System (ADS)

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.

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

2015-01-01

18

Piezoelectric and Ferroelectric Properties of Lead-Free Bi4?xNdxTi2.97V0.03O12 Ceramics  

Microsoft Academic Search

We fabricated lead-free Bi4?xNdxTi2.97V0.03O12 (x = 0.25?1.00; BNdTV-x) ceramics using the conventional solid-state reaction method and investigated their ferroelectric and piezoelectric properties. BNdTV ceramics exhibited the phase transition from orthorhombic to pseudo-tetragonal structure with increasing Nd concentration. At the morphotropic phase boundary of x = 0.85, BNdTV ceramics showed the highest values of Pr (13 ?C\\/cm), kt (17%) and Qm

Chang Won Ahn; Hai Joon Lee; Ill Won Kim; Jae Shin Lee; Won Kyoung Lee

2006-01-01

19

BiFeO3-doped (Na0.5K0.5)NbO3 lead-free piezoelectric ceramics  

NASA Astrophysics Data System (ADS)

Lead-free piezoelectric ceramics (1-x)(Na0.5K0.5)NbO3-xBiFeO3 (x=0~0.07) were synthesized by the solid-state reaction. Differential scanning calorimetry (DSC) measurements revealed that an increase in the amount of BiFeO3 dopant resulted in a decrease in the orthorhombic-tetragonal and tetragonal-cubic phase transition temperature of the material. One percent BiFeO3 additive suppressed grain growth, which not only benefits the sintering of ceramics but also enhances the piezoelectric and ferroelectric properties, where d33=145pC/N, kp=0.31, Qm=80, Pr=11.3 ?C cm-2 and Ec=16.5 kV cm-1. As xBF>0.01, both piezoelectric and ferroelectric properties decreased rapidly with an increasing amount of dopant.

Sun, Xueyi; Chen, Jun; Yu, Ranbo; Xing, Xianran; Qiao, Lijie; Liu, Guirong

2008-04-01

20

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

E-print Network

-free piezoelectric ceramics Fei-Fei Guo, Bin Yang, Shan-Tao Zhang, Xiao Liu, Li-Mei Zheng et al. Citation: J. Appl ceramics Appl. Phys. Lett. 101, 252905 (2012) Enhanced piezoelectric performance from carbon fluoropolymer phase boundary and electric properties in (12x)Bi0.5Na0.5TiO3-xBiCoO3 lead-free piezoelectric ceramics

Cao, Wenwu

21

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

NASA Astrophysics Data System (ADS)

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

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

2014-09-01

22

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

SciTech Connect

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 O–T 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.

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

23

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

PubMed

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

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

2015-03-11

24

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

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=301°C, electromechanical coupling factor,

Hajime Nagata; Masaki Yoshida; Yoichi Makiuchi; Tadashi Takenaka

2003-01-01

25

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

E-print Network

ceramics Dali Wang · Zhaohua Jiang · Bin Yang · Shantao Zhang · Mingfu Zhang · Feifei Guo · Wenwu Cao of lead-free (1-x)Ba(Hf0.16Ti0.84)O3­x (Ba0.70Ca0.30)TiO3 (BCHT) ceramics fabricated by the conventional been proposed based on their dielectric behavior. It is found that BHCT ceramics undergo a complicated

Cao, Wenwu

26

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

SciTech Connect

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

Wei, Yongbin; Jia, Yanmin, E-mail: wuzheng@zjnu.cn, E-mail: ymjia@zjnu.edu.cn; Wu, Jiang; Shen, Yichao [Department of Physics, Zhejiang Normal University, Jinhua 321004 (China); Wu, Zheng, E-mail: wuzheng@zjnu.cn, E-mail: ymjia@zjnu.edu.cn [College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua 321004 (China); Luo, Haosu [Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 201800 (China)

2014-07-28

27

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

NASA Astrophysics Data System (ADS)

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.

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

2014-07-01

28

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

NASA Astrophysics Data System (ADS)

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.

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

2015-02-01

29

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

NASA Astrophysics Data System (ADS)

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

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

2015-03-01

30

Temperature stability of ([Na{sub 0.5}K{sub 0.5}NbO{sub 3}]{sub 0.93}-[LiTaO{sub 3}]{sub 0.07}) lead-free piezoelectric ceramics  

SciTech Connect

A polymorphic phase transition (PPT) is often engineered into lead-free materials to generate high piezoelectric activity at room temperature, limiting their temperature stability. We report [Na{sub 0.5}K{sub 0.5}NbO{sub 3}]{sub 0.93}-[LiTaO{sub 3}]{sub 0.07} tetragonal ceramics with favorable properties over a broad temperature range due to a high Curie temperature at 447 deg. C and PPT at -15 deg. C involving a transition to a monoclinic rather than low temperature orthorhombic phase. Piezoelectric k{sub 31} and d{sub 31} coefficients varied from 0.19 to 0.14 and -53 to -33 pC/N, respectively, over the range of -15 to 300 deg. C. Strain-electric field loops provided strains of {approx}0.2% and a high-field d{sub 33} of 205 pm/V.

Skidmore, Thomas A.; Comyn, Tim P.; Milne, Steven J. [Institute for Materials Research, University of Leeds, Leeds LS2 9JT (United Kingdom)

2009-06-01

31

A lead-free piezoelectric transformer in radial vibration modes  

NASA Astrophysics Data System (ADS)

In this study, a disk-shaped piezoelectric transformer was fabricated using lead-free (K,Na)NbO3-based ceramics with high mechanical quality factor. The transformer can operate in the fundamental or the third radial vibration mode. The transformer is poled along the thickness direction. The top surface is covered by ring/dot silver electrodes separated by an annular gap which serve as the input and output parts of the transformer, respectively. The bottom surface, fully covered with a silver electrode, is grounded as a common electrode. The dimensions of the top ring/dot electrodes are designed such that the third radial vibration mode can be strongly excited. The electrical properties of the transformer with diameter of 34.2mm and thickness of 1.9mm were measured. For a temperature rise of 35°C, the transformer has a maximum output power of 12W. With the matching load, its maximum efficiency is >95%, and maximum voltage gains are 6.5 and 3.9 for the fundamental and the third radial vibration modes, respectively. It has potential to be used in power supply units and other electronic circuits.

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

2007-03-01

32

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

SciTech Connect

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

Lo, C. Y.; Choy, S. H.; Or, S. W.; Chan, H. L. W. [Department of Applied Physics and Materials Research Centre, Hong Kong Polytechnic University, Hunghom (Hong Kong)

2010-05-15

33

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

PubMed Central

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

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

2013-01-01

34

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

NASA Astrophysics Data System (ADS)

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 (184°C) and ferroelectric tetragonal to paraelectric cubic phases (385°C). It was observed that the ceramics calcined at 700°C and sintered at 1000°C shows the high Curie temperature, high dielectric permittivity and low dielectric loss. Further with increase in calcination temperature, the ferroelectric tetragonal to paraelectric cubic phase shifted to lower temperatures. Raman spectra of KNN ceramics were obtained and the three characteristic Raman peaks in the spectra of KNN are related to the internal vibrations of the NbO6 octahedron. The effect of processing parameters on dielectric properties and phase transitions studied systematically.

Mahesh, P.; Pamu, D.

2015-02-01

35

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

SciTech Connect

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

Jaita, Pharatree [Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Watcharapasorn, Anucha; Jiansirisomboon, Sukanda [Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Materials Science Research Center, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand)

2013-07-14

36

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

NASA Astrophysics Data System (ADS)

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

Li, Fei; Jin, Li; Guo, Runping

2014-12-01

37

Piezoelectric Ceramics and Their Applications  

ERIC Educational Resources Information Center

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

Flinn, I.

1975-01-01

38

Advances in Lead-Free Piezoelectric Materials for Sensors and Actuators  

PubMed Central

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

Aksel, Elena; Jones, Jacob L.

2010-01-01

39

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

SciTech Connect

Bismuth sodium titanate based lead-free ceramic fiber with the chemical formula of 0.885(Bi{sub 0.5}Na{sub 0.5})TiO{sub 3}-0.05(Bi{sub 0.5}K{sub 0.5})TiO{sub 3}-0.015(Bi{sub 0.5}Li{sub 0.5}= )TiO{sub 3}-0.05BaTiO{sub 3}, BNKLBT-1.5, has been fabricated by a powder-based extrusion method. The ceramic fibers with 400 {mu}m diameter were well crystallized after being calcined at 800 deg. C and sintered at 1170 deg. C. The piezoelectric and ferroelectric properties of the single fiber were found to be 155 pC/N and {approx}34.5 {mu}C/cm{sup 2}, respectively, which is comparable with that in bulk sample. 1-3 ceramic/polymer composites were fabricated by two routes, including dice and filled method and fiber pick-and-place method. Theoretical models were used to calculate the piezoelectric properties of the composites and compared with experimental results.

Choy, S. H.; Li, W. K.; Li, H. K.; Lam, K. H.; Chan, H. L. W. [Department of Applied Physics and Materials Research Centre, Hong Kong Polytechnic University, Hunghom, Kowloon, Hong Kong (China)

2007-12-01

40

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

PubMed

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

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

2014-08-14

41

Porous Piezoelectric Ceramic Transducer  

Microsoft Academic Search

Porous piezoelectric ceramics of Pb(Zr, Ti)O3, (P-PZT), have been newly developed to apply to transducers in an echo sounder. The P-PZT was prepared from a mixture of PZT and poly-methyl-methacrylate (PMMA) powders. The piezoelectric characteristics of the P-PZT such as the dielectric constant (?), voltage output constant (g constant), acoustic impedance (Zc) and Q were evaluated. The P-PZT was employed

Koichi Mizumura; Yoshiaki Kurihara; Hiroshi Ohashi; Susumu Kumamoto; Kiyonori Okuno

1991-01-01

42

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

NASA Astrophysics Data System (ADS)

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).

Jeon, Yu Hong

43

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

PubMed Central

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

2014-01-01

44

Lead-free NaNbO3 nanowires for a high output piezoelectric nanogenerator.  

PubMed

Perovskite ferroelectric nanowires have rarely been used for the conversion of tiny mechanical vibrations into electricity, in spite of their large piezoelectricity. Here we present a lead-free NaNbO(3) nanowire-based piezoelectric device as a high output and cost-effective flexible nanogenerator. The device consists of a NaNbO(3) nanowire-poly(dimethylsiloxane) (PDMS) polymer composite and Au/Cr-coated polymer films. High-quality NaNbO(3) nanowires can be grown by hydrothermal method at low temperature and can be poled by an electric field at room temperature. The NaNbO(3) nanowire-PDMS polymer composite device shows an output voltage of 3.2 V and output current of 72 nA (current density of 16 nA/cm(2)) under a compressive strain of 0.23%. These results imply that NaNbO(3) nanowires should be quite useful for large-scale lead-free piezoelectric nanogenerator applications. PMID:22098313

Jung, Jong Hoon; Lee, Minbaek; Hong, Jung-Il; Ding, Yong; Chen, Chih-Yen; Chou, Li-Jen; Wang, Zhong Lin

2011-12-27

45

Nanoscale characterization and local piezoelectric properties of lead-free KNN-LT-LS thin films  

NASA Astrophysics Data System (ADS)

We report the observation of domain structure and piezoelectric properties of pure and Mn-doped (K0.44,Na0.52,Li0.04)(Nb0.84,Ta0.1,Sb0.06)O3 (KNN-LT-LS) thin films on SrTiO3 substrates. It is revealed that, using piezoresponse force microscopy, ferroelectric domain structure in such 500 nm thin films comprised of primarily 180° domains. This was in accordance with the tetragonal structure of the films, confirmed by relative permittivity measurements and x-ray diffraction patterns. Effective piezoelectric coefficient (d33) of the films were calculated using piezoelectric displacement curves and shown to be ~53 pm V-1 for pure KNN-LT-LS thin films. This value is among the highest values reported for an epitaxial lead-free thin film and shows a great potential for KNN-LT-LS to serve as an alternative to PZT thin films in future applications.

Abazari, M.; Choi, T.; Cheong, S.-W.; Safari, A.

2010-01-01

46

First-principles study on novel lead-free piezoelectric materials  

NASA Astrophysics Data System (ADS)

In this study, we investigated systematically on perovskite oxides ABO3 through first-principles calculations based on density functional theory to find novel biocompatible lead-free piezoelectric materials. Biocompatible elements were picked out with HSAB ( Hard Soft Acids and Bases ) principle at the viewpoint of interaction energy with in-vivo molecules and they were applied to A and B of perovskite oxides ABO3. The stable combinations of constituent elements were specified with consideration for geometric and electric equilibrium condition. Then the stable cubic structure and the phonon properties were analyzed for the paraelectric non-polar phase. The soft modes, which induce a structural phase transition to non-centrosymmetric crystal structures, were distinguished with the phonon eigenfrequency and eigenvector. Additionally, insulation properties were estimated from band structure. As a result, five perovskite oxides, MgSiO3, MnSiO3, FeSiO3, ZnSiO3 and CaSiO3, were discovered as probable materials, which have band gap and soft modes progressing into tetragonal structure of ferroelectric phases. After the stable tetragonal structures were evaluated through initial setting of atomic positions based on soft modes, their material properties such as spontaneous polarization and piezoelectric stress constant were analyzed. Computations indicated tetragonal MgSiO3 exhibits relatively-large piezoelectricity.

Uetsuji, Y.; Tsuchiya, K.; Nakamachi, E.

2011-12-01

47

Piezoelectric Properties of (Bi1/2Na1/2)TiO3-Based Solid Solution for Lead-Free High-Power Applications  

NASA Astrophysics Data System (ADS)

Lead-free piezoelectric ceramics based on x(Bi1/2Na1/2)TiO3-y(Bi1/2Li1/2)TiO3-z(Bi1/2K1/2)TiO3 [x + y + z = 1] (abbreviated as BNLKT100y-100z) were prepared by conventional ceramic fabrication process. In this study, we clarified that the mechanical quality factor Qm of the rhombohedral side of the MPB composition is rather superior to that of the tetragonal side, although the piezoelectric constant d33 of the rhombohedral side is lower than that of the tetragonal side and MPB composition. As a second work, the effects of Mn doping on the variations in Td and piezoelectric properties including high-power characteristics were investigated using BNLKT4-8, which is a rhombohedral composition. The Qm of w wt % MnCO3-doped BNLKT4-8 (abbreviated as BNLKT4-8Mnw) markedly increased with increasing Mn concentration w, while Td, coupling factor k33, and d33 slightly decreased. The high-power characteristics of BNLKT4-8Mn0.6 were superior to those of hard PZT at a vibration velocity v0-p > 0.6 m/s. Therefore, a Mn-doped BNT-based solid solution with rhombohedral symmetry is a promising candidate for lead-free high-power applications.

Hiruma, Yuji; Watanabe, Tomomi; Nagata, Hajime; Takenaka, Tadashi

2008-09-01

48

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

NASA Astrophysics Data System (ADS)

The effect of Li and Mn substitution on the dielectric, ferroelectric and piezoelectric properties of lead free K0.5Na0.5NbO3 (KNN) was investigated. Samples were prepared using a conventional solid state reaction method. The sintering temperature for all the samples was 1050°C. The optimum doping concentration for the enhancement of different properties without the introduction of any other co-dopants such as Ti, Sb, and La was investigated. X-ray diffraction analysis confirmed that all the samples crystallize in a single phase perovskite structure. The dielectric properties were investigated as a function of temperature and applied electric field frequency. Compared with Li-substituted KNN (KLNN), Mn-substituted KNN (KMNN) exhibited a higher dielectric constant ? max (i.e., 4840) at its critical transition temperature T c (i.e., 421°C) along with a lower value of tangent loss at 10 kHz and greater values of saturation polarisation P s (i.e., 20.14 ?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.

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

2014-12-01

49

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

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

50

NEW LEAD-FREE PEROVSKITE RELAXOR CERAMICS DERIVED FROM BaTiO3 AND CONTAINING SCANDIUM  

E-print Network

NEW LEAD-FREE PEROVSKITE RELAXOR CERAMICS DERIVED FROM BaTiO3 AND CONTAINING SCANDIUM ANNIE SIMON-ray diffraction and dielectric characterizations. Dielectric measurements performed on ceramics with 0 x 0 therefore been performed in detail on ceramics with BaTiO3-derived compositions.2-23 Thanks to frequency

Boyer, Edmond

51

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

PubMed Central

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 orthorhombic–tetragonal 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

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

2014-01-01

52

Fracture mechanics for piezoelectric ceramics  

NASA Astrophysics Data System (ADS)

We Study cracks either in piezoelectrics, or on interfaces between piezoelectrics and other materials such as metal electrodes or polymer matrices. The projected applications include ferroelectric actuators operating statically or cyclically, over the major portion of the samples, in the linear regime of the constitutive curve, but the elevated field around defects causes the materials to undergo hysteresis locally. The fracture mechanics viewpoint is adopted—that is, except for a region localized at the crack tip, the materials are taken to be linearly piezoelectric. The problem thus breaks into two subproblems: (i) determining the macroscopic field regarding the crack tip as a physically structureless point, and (ii) considering the hysteresis and other irreversible processes near the crack tip at a relevant microscopic level. The first Subproblem, which prompts a phenomenological fracture theory, receives a thorough investigation in this paper. Griffith's energy accounting is extended to include energy change due to both deformation and polarization. Four modes of square root singularities are identified at the tip of a crack in a homogeneous piezoelectric. A new type of singularity is discovered around interface crack tips. Specifically, the singularities in general form two pairs: r {1}/{2}±i? and r {1}/{2}±i? , where ?. and k are real numbers depending on the constitutive constants. Also solved is a class of boundary value problems involving many cracks on the interface between half-spaces. Fracture mechanics are established for ferroelectric ceramics under smallscale hysteresis conditions, which facilitates the experimental study of fracture resistance and fatigue crack growth under combined mechanical and electrical loading. Both poled and unpoled fcrroelectrie ceramics are discussed.

Suo, Z.; Kuo, C.-M.; Barnett, D. M.; Willis, J. R.

1992-05-01

53

Finite Element Analysis of Piezoelectric Ceramic Speaker with Ansys Software  

E-print Network

ansys Finite Element Analysis of Piezoelectric Ceramic Speaker with Ansys Software 063 064090216 5 15 #12; 2010 5 15 #12; 3 3C (Mason) (Krimholtz) ansys ansys #12; ANSYS 4 Abstract The Piezoelectric ceramic piezoelectric speakers is a devices based

Wang, Ji

54

Characteristics of Acoustic Emission Sensor Using Lead-Free (LiNaK)(NaTaSb)O3 Ceramics for Fluid Leak Detection at Power Plant Valves  

NASA Astrophysics Data System (ADS)

In this study, acoustic emission (AE) sensor was fabricated using lead-free (LiNaK)-(NbTaSb)O3 ceramics for preventing environmental pollution. The structure of the AE sensor was designed as a Langevin-type one with air backing. The electromechanical coupling factor kp and piezoelectric constants d33 and g33 of lead-free (LiNaK)-(NbTaSb)O3 ceramics were 0.49, 300 pC/N, 27.02 mV·m/N, respectively. The peak sensitivity and frequency of the AE sensor using this ceramic material were 66.3 dB and 29.4 kHz, respectively. The results for fluid leak detection at a power plant valve were as follows; the peak frequency of response was 25 kHz at 2 and 6 kgf/cm2 N2 gas pressures, and increased up to 50 kHz at a 10 kgf/cm2 N2 gas pressure. The magnitude of the response voltage was about 40 mV at all the pressures.

Hong, Jaeil; Yoo, Juhyun; Lee, Kabsoo; Lee, Sangguk; Song, Hyunseon

2008-04-01

55

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

PubMed

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

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

2014-01-01

56

Characterization of Lead-Free B{sub 2}O{sub 3} Doped Barium Stannate Titanate Ceramics  

SciTech Connect

Lead-free barium stannate titanate ceramics doped with 2 wt% of B{sub 2}O{sub 3} were prepared via a solid state sintering. The optimum condition for the preparation was carried out. Properties of the lead free material were characterized by various methods. The high dielectric constant >14000 with low tan delta 0.040 was observed at 34 deg. C for the samples prepared at the optimum condition. Plots of dielectric permittivity as a function of temperature showed that the ceramics exhibit a diffuse ferroelectric-paraelectric phase transition. The dielectric constant was also measured as a function of electric field. The dielectric-electric field measurement indicated that this material exhibits a high tunability. In addition, mechanical property such as hardness was investigated. Relation between grain size and hardness of the ceramics was found to obey the Hall-Petch equation: H{sub v} = 0.07+12.9G{sup -(1/2)}.

Tawichai, N.; Pengpat, K.; Rujijanagul, G. [Department of Physics, Faculty of Science, Chiang Mai, University, 239 Huay Kaew Road, Suthep, Muang, 50200, Chiang Mai (Thailand)

2009-07-23

57

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

NASA Astrophysics Data System (ADS)

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

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

2011-08-01

58

Enhanced electrocaloric effect in lead-free BaTi1-xSnxO3 ceramics near room temperature  

NASA Astrophysics Data System (ADS)

The electrocaloric effect in lead-free BaTi1-xSnxO3 (BTSn, x = 0.08, 0.105, and 0.14) ferroelectric ceramics was studied by using an indirect method. It was found that the largest electrocaloric response could be achieved in BTSn with x = xQP = 0.105 near room temperature with an adiabatic temperature change ?T of 0.61 K and an electrocaloric strength ?T/?E of 0.31 K mm kV-1, under a modest electric field ?E of 20 kV cm-1, which is comparable with the best values reported in lead-free materials. These enhanced values are attributed to the multiphase (four phases) coexistence at x = xQP corresponding to the quasi-quadruple point composition.

Luo, Zhengdong; Zhang, Dawei; Liu, Yang; Zhou, Di; Yao, Yonggang; Liu, Chenqi; Dkhil, Brahim; Ren, Xiaobing; Lou, Xiaojie

2014-09-01

59

Porous Piezoelectric Ceramics—A Historical Overview  

Microsoft Academic Search

A brief review of porosity origin, microstructure peculiarities, fabrication methods, and mathematical models, as well as experimental data for different porous piezoceramics were presented. Critical comparison of FEM calculations with the results of various approximated formulas, unit cell models, and experimental data for porous piezoceramics was carried out. Complex sets of elastic, dielectric and piezoelectric coefficients of porous ceramics were

Andrey N. Rybyanets

2011-01-01

60

Porous Piezoelectric Ceramics - A historical overview  

Microsoft Academic Search

A brief review of porosity origin, microstructure peculiarities, fabrication methods, and mathematical models, as well as experimental data for different porous piezoceramics were presented. Critical comparison of FEM calculations with the results of various approximated formulas, unit cell models, and experimental data for porous piezoceramics was carried out. Complex sets of elastic, dielectric and piezoelectric coefficients of porous ceramics were

Andrey N. Rybyanets

2010-01-01

61

Fabrication of piezoelectric ceramic\\/polymer composites by injection molding  

Microsoft Academic Search

Ceramic injection molding has been shown to be a viable process for fabricating both PZT (lead zirconate titanate) ceramics and piezoelectric ceramic\\/polymer transducers. The electrical properties of injection-molded PZT ceramics are comparable with those of ceramics prepared by conventional powder pressing, with no evidence of deleterious effects from metallic contamination and molding equipment. By using ceramic injection molding to fabricate

Leslie J. Bowen; Kenneth W. French

1992-01-01

62

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

SciTech Connect

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.

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

2012-12-15

63

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

SciTech Connect

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.

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

64

Numerical characterization of soft piezoelectric ceramics  

NASA Astrophysics Data System (ADS)

Numerical simulations of piezoelectric ceramics can give detailed information about their static and dynamic behaviours. Resonance frequencies, mechanical displacements and other values of interest can be obtained using well known techniques, such as Finite Element Method (FEM). However, the predictions of such methods are strongly limited by the accuracy of the parameters in the piezoceramic model. Assuming a linear behaviour, five elastic constants, three piezoelectric constants, two dielectric constants and the mass density are needed to simulate piezoceramics belonging to the 6-mm symmetry class. In a recent work, our research group presents a novel methodology to obtain the parameters of piezoelectric ceramic disks based on FEM simulations in a set of ten hard PZT ceramics. In this work, the proposed methodology is applied for the characterization of two soft PZT ceramics (Pz27 from Ferroperm and APC850 from APC International) typically used in ultrasound applications. To provide the error bound two different thicknesses (frequencies of 1 MHz and 2 MHz) and three different diameters (10 mm, 20 mm and 30 mm) are used in the characterization, the mean value over this set is used to characterize the material itself. A set of ten samples belonging to a single fabrication batch is used to estimate the error bound for identical samples. The results adjust the impedance curves over a wide band of frequencies, including the radial modes, the thickness mode and other coupled modes.

Pérez, Nicolás; Buiochi, Flavio; Andrade, Marco A. B.; Adamowski, Julio C.

2012-05-01

65

Development of a Templated Grain Growth System for Texturing Piezoelectric Ceramics  

E-print Network

Development of a Templated Grain Growth System for Texturing Piezoelectric Ceramics MATTHEW M be obtained from crystallographically textured piezoelectric ceramics. Single crystal piezoelectrics costs. NexTech Materials is developing textured piezoelectrics via Templated Grain Growth

Azad, Abdul-Majeed

66

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)

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

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

2015-02-01

67

Enhanced pyroelectric properties of Cax(Sr0.5Ba0.5)1-xNb2O6 lead-free ceramics  

NASA Astrophysics Data System (ADS)

Cax(Sr0.5Ba0.5)1-xNb2O6 [CSBN(x), x = 0.00, 0.10, 0.15, and 0.20] lead-Free ceramics were prepared by a traditional solid-state reaction technique. Dielectric, ferroelectric, and pyroelectric properties of CSBN(x) lead-Free ceramics were systematically investigated. The pyroelectric properties of CSBN(x) have been enhanced remarkably due to Ca addition and reached the maximum values at x = 0.15, with pyroelectric coefficient of 3.61 × 10-8 C/cm2 K and pyroelectric figure of merit of Fi = 172 pm/V, Fv = 0.021 m2/C, and Fd = 11.5 ?Pa-1/2, which are superior to other lead-free ferroelectric ceramics. These results indicate the potential of CSBN(x) ceramics for infrared detector applications.

Zhang, Jing; Dong, Xianlin; Cao, Fei; Guo, Shaobo; Wang, Genshui

2013-03-01

68

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

NASA Astrophysics Data System (ADS)

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.

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

2012-09-01

69

Promotion of osteogenesis by a piezoelectric biological ceramic.  

PubMed

Hydroxyapatite (HA) ceramic and piezoelectric biological ceramic, hydroxyapatite and barium titanate (HABT), were implanted in the jawbones of dogs. Histological observation showed that, compared with HA ceramics, HABT promoted the growth and repair of the bone significantly, the tissue growth around the HABT ceramic was direction-dependent, the collagen arranged orderly and the bone grew orderly. The order growth of the bone increased the efficiency of osteogenesis on the surface of the implanted HABT ceramics. PMID:9430335

Feng, J; Yuan, H; Zhang, X

1997-12-01

70

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

SciTech Connect

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

Liu, Feng [The Key Laboratory of Inorganic Functional Materials and Devices, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Wahyudi, Olivia; Li, Yongxiang, E-mail: yxli@mail.sic.ac.cn [The Key Laboratory of Inorganic Functional Materials and Devices, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China)

2014-03-21

71

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

PubMed

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

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

2015-04-24

72

Embedded piezoelectric ceramic transducers in sandwiched beams  

NASA Astrophysics Data System (ADS)

Surface bonded piezoelectric ceramic (PZT) transducers are currently the most prominent area of research in structural health monitoring using electromechanical impedance methods. This paper presents a new embedded PZT patch and its interaction with the host sandwiched beam. Durability and protection from surface finish, vandalism and the environment are important features of the embedment. The paper also demonstrates the use of thickness vibration of the PZT patch in electromechanical admittance formulations. This embedded PZT-structure interaction model is based on the new concept of 'average sum impedance'. The formulations used for this model can be conveniently employed to extract the mechanical impedance of any 'unknown' PZT patch embeddable plane structure. The mechanical impedance of the structure is obtained from the admittance signatures of the embedded PZT patch. The proposed model is experimentally verified on sandwiched beams.

Gopal Madhav Annamdas, Venu; Kiong Soh, Chee

2006-04-01

73

High-Temperature Piezoelectric Ceramic Developed  

NASA Technical Reports Server (NTRS)

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.

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

2005-01-01

74

Piezoelectric properties of PLZT ceramics at different remanent polarization levels  

Microsoft Academic Search

The piezoelectric, electromechanical, and dielectric properties of lead lanthanum zirconate titanate (PLZT) ceramics at different remanent polarization levels were studied for acoustic imaging applications. The remanent polarizations at different levels were achieved by applying electric switching pulses with different widths. The piezoelectric coefficient obtained by direct and converse effects decreased with the remanent polarization, but the relations were not linear.

H. Wang; R. E. Newnham; L. E. Cross; W. Y. Pan

1990-01-01

75

Lead-free piezoceramics  

Microsoft Academic Search

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

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

2004-01-01

76

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

NASA Astrophysics Data System (ADS)

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 <30mA/m2 even at a high electric field of 145kV/cm. The piezoelectric d33 coefficients of the ceramics before and after annealing at 550°C for 4h are measured to be ˜28 and ˜24pC/N, respectively. These values are higher than those of most major lead-free high-temperature piezoelectric ceramics.

Yuan, G. L.; Or, Siu Wing

2006-02-01

77

Temperature dependence of piezoelectric properties for textured SBN ceramics  

Microsoft Academic Search

Temperature dependences of piezoelectric properties were studied for (001) textured ceramics of bismuth layer-structured ferroelectrics, SrBi2Nb2O9 (SBN). The textured ceramics with varied orientation degrees were fabricated by templated, grain-growth method, and the temperature dependences of resonance frequency were estimated. Excellent temperature stability of resonance frequency was obtained for the 76% textured ceramics. The resonance frequency of the 76% textured specimens

Masahiko Kimura; Hirozumi Ogawa; Daisuke Kuroda; Takuya Sawada; Yukio Higuchi; Hiroshi Takagi; Yukio Sakabe

2007-01-01

78

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

E-print Network

Influence of sample size on ultrasonic phase velocity measurements in piezoelectric ceramics Rui Piezoelectric materials are widely used in various elec- tromechanical devices. Along with density and permittivity, elastic and piezoelectric constants are the fundamental pa- rameters of these materials

Cao, Wenwu

79

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

SciTech Connect

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.

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

80

Strain enhancement of lead-free Bi1/2(Na0.82K0.18)1/2TiO3 ceramics by Sn doping  

NASA Astrophysics Data System (ADS)

The effects of Sn doping on the crystal structure, electric-field-induced strain (EFIS), and piezoelectric properties of Bi1/2(Na0.82K0.18)1/2TiO3 ceramics have been investigated. Sn doping resulted in a transition from ferroelectric (FE) tetragonal to electrostrictive (ES) pseudocubic symmetry, leading to degradations of the piezoelectric coupling coefficient, electromechanical quality factor, and piezoelectric coefficient d 33. However, the EFIS was significantly enhanced by the Sn-dopinginduced phase transition and reached its highest value of S max / E max = 585 pm/V when 5 mol% SnO2 was doped, which is close to the FE-ES phase boundary. To explain the giant strain, we suggest a model on the basis of a field-induced phase transition from nonpolar to polar symmetry under external fields.

Lee, Jae-Shin; Pham, Ky-Nam; Han, Hyoung-Su; Lee, Han-Bok; Tran, Vu Diem Ngoc

2012-01-01

81

Strong Piezoelectricity in (1 - x)(K0.4Na0.6)(Nb0.96Sb0.04)O3-xBi0.5K0.5Zr1-ySnyO3 Lead-Free Binary System: Identification and Role of Multiphase Coexistence.  

PubMed

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

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

2015-03-18

82

Manufacturing of PZT-nickel functionally graded piezoelectric ceramics  

NASA Astrophysics Data System (ADS)

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

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

2012-05-01

83

Nyquist Relation and Its Validity for Piezoelectric Ceramics Considering Temperature  

NASA Astrophysics Data System (ADS)

In this paper, we focused on validity of the Nyquist relation for piezoelectric ceramics in temperatures 303 K-393 K. The electrical impedance and noise spectral density were measured and compared for every 10 K in frequency range 100 kHz-1 MHz. The measurements were made in thermal stable condition and under equilibrium conditions in the case of noise measurement.

Sedlak, Petr; Majzner, Jiri; Sikula, Josef

2009-04-01

84

Study on the sandwich piezoelectric ceramic ultrasonic transducer in thickness vibration  

Microsoft Academic Search

A sandwich piezoelectric ceramic ultrasonic transducer in thickness vibration is studied. The transducer consists of front and back metal masses, and coaxially segmented, thickness polarized piezoelectric ceramic thin rings. For this kind of sandwich piezoelectric transducers in thickness vibration, it is required that the lateral dimension of the transducer is sufficiently large compared with its longitudinal dimension so that no

Shuyu Lin; Hua Tian

2008-01-01

85

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

NASA Astrophysics Data System (ADS)

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.

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

86

Piezoelectric ceramic assembly tubes for torsional actuators  

NASA Astrophysics Data System (ADS)

The efforts described here are intended to provide a basis for the utilization of novel piezoelectric actuators in smart materials and structures. The actuator design developed in this study is a segmented, piezoelectric tube, with the individual segments driven in a d15 shear mode. The PZT-5A tubes were cut longitudinally in to an even number of equal slender segments. These slender segments were poled individually along their length using a continuous poling technique developed at NRL. The polarization of the poled segments alternates in direction between adjacent segments. The segments were reassembled with a conductive epoxy so that it serves as both joint and electrode. The assembled actuator tubes were evaluated by applying electric field normal to the polarization direction of the segments, demonstrating proof of concept. These solid state prototype devices were driven to precise angular displacement and torque output. Reliability test, including both fatigue and mechanical loading of the device, were conducted. In conjunction with this effort, numerical computation analyses were performed with respect to structural integrity versus segment joint thickness, and the relative effect of cylindrical versus polygonal configurations. These studies facilitated the successful production of prototypes. Projected actuator outputs based on electromechanical test results are also discussed in terms of requirements for noise and vibration control of helicopter rotor blades.

Kim, Chulho; Glazounov, Alexandre E.; Flippen, Luther D.; Pattnaik, Amitav; Zhang, Qi Ming; Lewis, David, III

1999-07-01

87

Realization of high-energy density polycrystalline piezoelectric ceramics  

SciTech Connect

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.

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

2006-01-16

88

Realization of high-energy density polycrystalline piezoelectric ceramics  

NASA Astrophysics Data System (ADS)

This letter reports a high energy density piezoelectric material in the system given as: Pb[(Zr0.52Ti0.48)O3]1-x[(Zn1/3Nb2/3)O3]x+yMnCO3, where x =0.1 and y varies from 0.5to0.9wt%. 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?=?n, where ? 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 g33 and d33 was found to be 55.56×10-3m2/C and 291×10-12C/N, respectively, yielding the magnitude product d33•g33 as ˜16168×10-15m2/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.

Islam, Rashed Adnan; Priya, Shashank

2006-01-01

89

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

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.

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

90

High-Power Piezoelectric Characteristics of Bi4Ti3O12-SrBi4Ti4O15-Based Ferroelectric Ceramics  

NASA Astrophysics Data System (ADS)

The high-power piezoelectric characteristics of lead-free piezoelectric ceramics based on a mixed bismuth layer-structured ferroelectric, Bi4Ti3O12-SrBi4Ti4O15 (abbreviated as BIT-SBTi) were studied. In addition, MnCO3-doped BIT-SBTi (abbreviated as BIT-SBTi + Mn x wt %) were prepared to improve their high-power piezoelectric properties such as the mechanical quality factor Qm. In the case of pure BIT-SBTi, its vibration velocity v0-p at 5 V/mm field is 1.5 m/s. The v0-p values of the BIT-SBTi + Mn 0.2 and 0.4 wt % ceramics were above 2.0 m/s at 5 V/mm. Also, we observed that the mechanical quality factor Qm at a large amplitude of BIT-SBTi + Mn 0.4 wt % was maintained higher than 4000 at v0-p of 2.0 m/s. The high-power characteristics of BIT-SBTi + Mn x wt % were superior to those of hard Pb(Zr,Ti)O3 (abbreviated as PZT) at a vibration velocity v0-p>1.0 m/s. Therefore, Mn-doped BIT-SBTi-based ceramics are a promising candidate for lead-free high-power applications.

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

2010-09-01

91

High-Power Piezoelectric Characteristics at Continuous Driving of Bi4Ti3O12-SrBi4Ti4O15-Based Ferroelectric Ceramics  

NASA Astrophysics Data System (ADS)

The high-power piezoelectric characteristics at continuous driving were studied on lead-free piezoelectric ceramics of a mixed bismuth layer-structured ferroelectric, Bi4Ti3O12-SrBi4Ti4O15 (abbreviated as BIT-SBTi) with MnCO3-doping (abbreviated as BIT-SBTi + Mn x wt %). MnCO3-doping to BIT-SBTi can improve its high-power piezoelectric properties such as the mechanical quality factor Qm. The vibration velocity, v0-p, of the BIT-SBTi + Mn 0.2 wt % ceramics was above 2.0 m/s at 5 V/mm in the case of short- and long-time driving. Also, we observed that the resonance frequency change and temperature on the sample surface at a long-time driving for BIT-SBTi + Mn 0.2 wt % were less than 1.0% and 50 °C at v0-p of 2.0 m/s, respectively. The high-power characteristics of BIT-SBTi + Mn x wt % were superior to those of hard Pb(Zr,Ti)O3 (abbreviated as PZT) at a vibration velocity v0-p > 1.0 m/s. Therefore, Mn-doped BIT-SBTi-based ceramics are a promising candidate for lead-free high-power applications requiring frequency stability and long-time driving.

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

2011-07-01

92

Uniaxial stress dependence of the piezoelectric properties of lead zirconate titanate ceramics  

Microsoft Academic Search

Piezoelectric ceramics are often used under compressive stress. We have measured the dynamic value of the piezoelectric charge coefficient, d33, as a function of uniaxial stress in the poled direction. Results on two types of PZT ceramics manufactured by EDO Corporation are presented; in general, they show a nonlinear behaviour with an initial increase in d33 as the stress increases

G. Yang; S.-F. Liu; W. Ren; B. K. Mukherjee

2000-01-01

93

Local and global energy release rates for an electrically yielded crack in a piezoelectric ceramic  

Microsoft Academic Search

Structural reliability concerns of various electromechanical devices call for a better understanding of the mechanisms of fracture in piezoelectric ceramics subjected to combined mechanical and electrical loading. For these materials, due to unexplained discrepancies between theory and experiments, even the basic criterion of fracture remains a point of controversy. A viewpoint adopted in this paper is to model piezoelectric ceramics

Huajian Gao; Tong-Yi Zhang; Pin Tong

1997-01-01

94

Utilisation of smart polymers and ceramic based piezoelectric materials for scavenging wasted energy  

Microsoft Academic Search

Piezoelectric smart polymer and ceramic materials can be deployed as a mechanism to transform mechanical energy into electrical energy that can be stored and used to power portable devices. This paper focuses on the development and comparison of a micropower based harvesting generator using piezoelectric PZT (lead zirconate titanate) ceramic, PVDF (polyvinylidene fluoride) membrane and PP (polypropylene) foam polymer with

I. Patel; E. Siores; T. Shah

2010-01-01

95

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

SciTech Connect

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

Li Zhu, Xiao [Department of Materials Science and Engineering, Laboratory of Dielectric Materials, Zhejiang University, 38 Zheda Road, Hangzhou 310027 (China) [Department of Materials Science and Engineering, Laboratory of Dielectric Materials, Zhejiang University, 38 Zheda Road, Hangzhou 310027 (China); Department of Materials and Ceramic Engineering, Centre for Research in Ceramics and Composite Materials, CICECO, University of Aveiro, 3810-193 Aveiro (Portugal); Li, Kun; Qiang Liu, Xiao; Ming Chen, Xiang [Department of Materials Science and Engineering, Laboratory of Dielectric Materials, Zhejiang University, 38 Zheda Road, Hangzhou 310027 (China)] [Department of Materials Science and Engineering, Laboratory of Dielectric Materials, Zhejiang University, 38 Zheda Road, Hangzhou 310027 (China); Asif Rafiq, Muhammad [Department of Materials and Ceramic Engineering, Centre for Research in Ceramics and Composite Materials, CICECO, University of Aveiro, 3810-193 Aveiro (Portugal)] [Department of Materials and Ceramic Engineering, Centre for Research in Ceramics and Composite Materials, CICECO, University of Aveiro, 3810-193 Aveiro (Portugal)

2013-09-28

96

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

Microsoft Academic Search

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

Yang Jing; Jianbin Luo; Wenyan Yang; Guoxian Ju

2004-01-01

97

Measurement of Micro Vibration of Car by Piezoelectric Ceramics  

NASA Astrophysics Data System (ADS)

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.

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

98

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

NASA Astrophysics Data System (ADS)

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

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

2015-02-01

99

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

NASA Astrophysics Data System (ADS)

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).

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

2013-10-01

100

Electrical power generation characteristics of PZT piezoelectric ceramics.  

PubMed

The electrical power generation characteristics of Mn-doped PZT ceramics responding to slow mechanical stress as well as to impact stress have been investigated. Although both the slow and impact stresses induce a reversible electrical response, the generation properties are distinctly different. Slow stress releases two output current peaks with opposite directions, responding to the increasing and decreasing part of the stress, respectively. However, impact stress produces a nearly one-directional signal. The output charge and energy by slow stress are found to be two orders of magnitude higher than that produced by impact stress. This work shows that the energy conversion efficiency of piezoelectric ceramics strongly depends on the method of stress application. PMID:18244261

Xu, C N; Akiyama, M; Nonaka, K; Watanabe, T

1998-01-01

101

Determination of the piezoelectric coefficients d ij of PZT ceramics and composites by laser interferometry  

Microsoft Academic Search

We have measured the piezoelectric coefficients of PZT ceramics by resonance and laser interferometry methods. The surface displacement was measured by a single-beam Michelson interferometer. A stable double-beam interferometer was also used to suppress the effect of bending. The piezoelectric coefficients dij of the PZT ceramic and of the 0–3 ceramic–polymer composites were determined from the displacements. The results for

L Burianová; M Šulc; M Prokopová

2001-01-01

102

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

NASA Astrophysics Data System (ADS)

A structural coexistence of rhombohedral (R) and tetragonal (T) phases has been revealed in the (001)c-cut lead-free 0.93(Bi1/2Na1/2)TiO3-0.07BaTiO3 (BNB7T) piezoelectric crystals, which grown by the self-flux method, in the lower temperatures by high-resolution synchrotron X-ray diffraction, reciprocal space mapping, and transmission electron microscopy. The dielectric permittivity exhibits a thermal hysteresis in the region of 120-260 °C, implying a first-order-like phase transition from R+T to T. The real part (?') of dielectric permittivity begins to deviates from the Curie-Weiss equation, ?' = C/(T - To), from the Burns temperature TB = 460 °C, below which the polar nanoregions (or nanoclusters) develop and attenuate dielectric responses. The polar nanoregions of 5-10 nm were revealed by high-resolution transmission electron microscope. The normal piezoelectric coefficient d33 exhibits a rapid increase at E = 15-20 kV/cm and reaches a maximum of d33 ˜450 pC/N. The high piezoelectric response and E-field induced strain in BNB7T single crystals can be attributed to structural phase transitions under an E-field application.

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

2014-01-01

103

(1 - x)(K0.48Na0.52)(Nb0.95-y-zTazSby)O3-xBi0.5(Na0.82K0.18)0.5ZrO3 lead-free ceramics: composition dependence of the phase boundaries and electrical properties.  

PubMed

In this work, (1 - x)(K0.48Na0.52)(Nb0.95-y-zTazSby)O3-xBi0.5(Na0.82K0.18)0.5ZrO3, {abbreviation: KNNST-BNKZ-x-y-z} lead-free piezoceramics were prepared by a conventional solid-state reaction method, and the composition dependence of their phase structures and electrical properties was systematically discussed. Doping with Sb(5+), Ta(5+), and BNKZ plays an important role on the phase boundaries as well as piezoelectric activity. A three-phase coexistence involving rhombohedral-orthorhombic-tetragonal (R-O-T) phases was observed in the ceramics with 0.0325 ? x ? 0.05, 0.035 ? x ? 0.065, 0.05 ? z ? 0.08, indicating that doping with BNKZ, Ta(5+), and Sb(5+) can induce the formation of such a phase boundary by simultaneously increasing TR-O and decreasing TO-T. Enhanced piezoelectric behavior was observed in the ceramics located in the composition region of the R-O-T phase boundary, and a high d33 value of 400 pC N(-1) can be attained by refining their compositions (e.g., x = 0.0325, y = 0.035, and z = 0.05), together with a high TC value of ?240 °C. Of particular interest is that a large electric field-induced strain of 0.18% (Smax/Emax = 706 pm V(-1)) was also found in the ceramics with x = 0.0325, y = 0.035, and z = 0.05 under a low electric field of 2.5 kV mm(-1). As a result, the piezoelectric activity as well as the strain can be operated in the material system by refining x, y, and z content. PMID:25679361

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

2015-02-24

104

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)

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

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

2015-02-01

105

Porosity Dependence of Piezoelectric Properties for Porous Potassium Niobate System Ceramics  

NASA Astrophysics Data System (ADS)

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.

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

2011-10-01

106

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

NASA Astrophysics Data System (ADS)

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.

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

2009-07-01

107

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

NASA Astrophysics Data System (ADS)

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.

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

2014-03-01

108

Lead-free piezoelectric (K0.5Na0.5)NbO3 thin films derived from chemical solution modified with stabilizing agents  

NASA Astrophysics Data System (ADS)

(K0.5Na0.5)NbO3 (KNN)-based ferroelectric thin films were prepared by a chemical solution approach modified with both diethanolamine (DEA) and ethylenediaminetetraacetic acid (EDTA) as the stabilizing agents. The obtained KNN thin films exhibited a remarkably low leakage current and well-saturated polarization hysteresis loop. The effective piezoelectric strain coefficient d33 and voltage coefficient g33 under the clamping of the substrate were improved to 74.0 pm/V and 28.3 mm V/N, respectively. The reason for the superior properties was found that the addition of EDTA and DEA was effective in suppressing the volatilization of K and Na at moderate temperature before the crystallization.

Goh, Phoi Chin; Yao, Kui; Chen, Zhong

2010-09-01

109

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

E-print Network

Theoretical study on the static performance of piezoelectric ceramic- polymer composites with 1 1992) Inhomogeneous displacement profiles have been derived for a single-rod composite and a single piezoelectric constants for the composites have been derived in terms of the ceramic content, the piezoelectric

Cao, Wenwu

110

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

SciTech Connect

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

Chen, Y.Q. [Key Laboratory of Low Dimensional Materials and Application Technology of Ministry of Education, and Faculty of Materials, Optoelectronics and Physics, Xiangtan University, Xiangtan, Hunan 411105 (China)] [Key Laboratory of Low Dimensional Materials and Application Technology of Ministry of Education, and Faculty of Materials, Optoelectronics and Physics, Xiangtan University, Xiangtan, Hunan 411105 (China); Zheng, X.J., E-mail: zhengxuejun@xtu.edu.cn [Key Laboratory of Low Dimensional Materials and Application Technology of Ministry of Education, and Faculty of Materials, Optoelectronics and Physics, Xiangtan University, Xiangtan, Hunan 411105 (China); Feng, X. [School of Aerospace, Tsinghua University, Beijing 100084 (China)] [School of Aerospace, Tsinghua University, Beijing 100084 (China); Dai, S.H.; Zhang, D.Z. [Key Laboratory of Low Dimensional Materials and Application Technology of Ministry of Education, and Faculty of Materials, Optoelectronics and Physics, Xiangtan University, Xiangtan, Hunan 411105 (China)] [Key Laboratory of Low Dimensional Materials and Application Technology of Ministry of Education, and Faculty of Materials, Optoelectronics and Physics, Xiangtan University, Xiangtan, Hunan 411105 (China)

2010-06-15

111

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

NASA Technical Reports Server (NTRS)

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

Bryant, Robert G.

2007-01-01

112

Optical Measurement of Piezoelectric Vibration in Circular Rod and Disk Ceramics  

Microsoft Academic Search

The fiber-optic measurement and evaluation of piezoelectric vibration of circular rod and disk ceramics are described. The values corresponding to the piezoelectric d- and g-constants can be obtained locally by measuring amplitude and Q-value at the first-resonance frequency under appropriate electric conditions. The results are analyzed numerically by using the theory of coupled resonance.

Michio Ohki; Naomi Shima; Tadashi Shiosaki

1992-01-01

113

Functional microwave flat antenna using alumina ceramic substrate and piezoelectric actuator  

Microsoft Academic Search

We have demonstrated a new-type microstrip patch antenna on a dielectric ceramic substrate with a mechanism of a variable antenna height using a mechatronics technology. The functional microwave flat antenna with an alumina ceramic substrate was controlled by a piezoelectric actuator, and changed the resonant frequencies. We have confirmed a possible variation of the antenna resonant frequency of 96% from

Kazuhiro Kitatani; Yuichi Sakaguchi; Yasuyuki Okamura

2006-01-01

114

Using Piezoelectric Ceramics for Dust Mitigation of Space Suits  

NASA Technical Reports Server (NTRS)

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

Angel, Heather K.

2004-01-01

115

A novel approach to electrochromism in WO3 thin film using piezoelectric ceramics for power supply  

NASA Astrophysics Data System (ADS)

Electrochromism was newly realized in a WO3-Pb(Zroverflow="scroll">0.52Ti0.48)Ooverflow="scroll">3 (PZT) system which utilized the piezoelectric property of PZT ceramics for power supply. The electric power produced by Mn-doped PZT ceramics enabled the WO3 film to color blue. High piezoelectricity with a peak voltage of 35 V and peak current of 1.2 mA on a 30 k? circuit was observed at a pressure of 30 MPa for the present system. This study shows the possibility to actuate the electrochromic WO3 film with PZT ceramics.

Xu, C. N.; Akiyama, M.; Sun, P.; Watanabe, T.

1997-03-01

116

Piezoelectric Properties of Grain-Oriented Bismuth Layer-Structured Ferroelectric Ceramics  

Microsoft Academic Search

Piezoelectric properties of grain-oriented bismuth layer-structured ferroelectric (BLSF) ceramics, such as Bi4,xPbxTi3,xNbx0~2 (BPTN) and Pbl,x(NaBi)x\\/2Bi4Ti40i5 (PNBT) prepared by the hot-forging (H.F.) method, are studied from the viewpoint of grain orientation. The grain orientation (H.F.) makes the piezoelectric properties of BLSF ceramics much more pronounced than those of non-oriented (O.F.) ceramics. The crystal symmetry of the poled H.F. BLSF piezoceramics appears

Tadashi TAKENAKA; Koichiro SAKATA

1986-01-01

117

Intelligent motion control for linear piezoelectric ceramic motor drive.  

PubMed

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

Wai, Rong-Jong; Lee, Jeng-Dao

2004-10-01

118

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)

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).

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

2015-01-01

119

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

PubMed

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

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

2011-09-01

120

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

NASA Astrophysics Data System (ADS)

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.

Dong, Biqin

121

Lead-free transducer for non-destructive evaluation  

NASA Astrophysics Data System (ADS)

Lead-free piezoelectric ceramics with the formula 0.90(Bi0.5Na0.5)TiO3 - 0.05(Bi0.5K0.5)TiO3 - 0.015(Bi0.5Li0.5)TiO3-0.05BaTiO3 (abbreviated as BNKLBT-1.5) were prepared by a conventional mixed-oxide method. A disc of this material was fabricated and used to construct an ultrasonic transducer suitable for use in non-destructive evaluation (NDE). Using a laser vibrometer, it was observed that both BNKLBT and PZT exhibited a surface displacement pattern indicative of coupling of the radial mode vibration with the thickness mode vibration. This is consistent with the measurements of electrical impedance vs frequency which showed that for both discs a strong radial mode with many harmonics was clearly observed and many (usually undesired) modes existed near the thickness mode resonance frequency. The discs were mounted in stainless steel housings with appropriate electrical connections to form transducers. Tungsten/epoxy backing was incorporated to provide a very short ring-down time, a characteristic required for many NDE applications. The characteristics of the BNKLBT transducer were quite similar to that of a PZT transducer of similar structure, showing that this lead-free material has the potential to replace PZT in transducers for NDE applications.

Edwards, G. C.; Choy, S. H.; Chan, H. L. W.; Scott, D. A.; Batten, A.

2007-07-01

122

Determination of temperature dependence of piezoelectric coefficients matrix of lead zirconate titanate ceramics by quasi-static and resonance method  

NASA Astrophysics Data System (ADS)

The piezoelectric coefficients (d33, -d31, d15, g33, -g31, g15) of soft and hard lead zirconate titanate ceramics were measured by the quasi-static and resonance methods, at temperatures from 20 to 300 °C. The results showed that the piezoelectric coefficients d33, -d31 and d15 obtained by these two methods increased with increasing temperature for both hard and soft PZT ceramics, while the piezoelectric coefficients g33, -g31 and g15 decreased with increasing temperature for both hard and soft PZT ceramics. In this paper, the observed results were also discussed in terms of intrinsic and extrinsic contributions to piezoelectric response.

Li, Fei; Xu, Zhuo; Wei, Xiaoyong; Yao, Xi

2009-05-01

123

Piezoelectric Properties of Bismuth Layer-Structured Ferroelectric Ceramics with Sr-Bi-Ti-Ta System  

Microsoft Academic Search

Grain orientation effects of Sr-Bi-Ti-Ta system, especially Sr x Bi 4 m x Ti 3 m x Ta x O 12 ( m = 3, x = 0-2) [SBTT3( x )] ceramics which belong to a bismuth layer-structured ferroelectric (BLSF) family, are studied using the hot-forging (HF) method on their piezoelectric properties. The grain orientation (HF) effects enhance the piezoelectric

Hajime Nagata; Tadashi Takenaka

2002-01-01

124

Study on the prestressed sandwich piezoelectric ceramic ultrasonic transducer of torsional-flexural composite vibrational mode.  

PubMed

Based on the classical torsional and flexural vibrational theory of a slender rod, the prestressed sandwich torsional-flexural composite mode piezoelectric ceramic ultrasonic transducer is studied. This type of transducer consists of the slender metal rods and the longitudinally and tangentially polarized piezoelectric ceramic rings. The resonance frequency equations for the torsional and flexural vibrations in the transducers are derived. The simultaneous resonance of the torsional and flexural vibrations in the transducer is acquired by correcting the length of the metal slender rods resulting from the piezoelectric ceramic elements. The experimental results show that the measured resonance frequencies of the transducers are in good agreement with the computed ones, and the measured resonance frequencies of the torsional and the flexural vibrations in the composite transducers are also in good agreement with each other. PMID:12186032

Shuyu, Lin

2002-08-01

125

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

PubMed

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

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

2000-03-01

126

Piezoelectric Ceramics Nonlinear Behavior. Application to Langevin Transducer  

NASA Astrophysics Data System (ADS)

Drastic behavior changes occur for power transducers using PZT type of ceramics. A better characterization under high excitations is then required for piezoelectric materials Indeed, characteristic nonlinear behaviors such as resonance frequency shift with hysteresis effect and overtones generation are observed experimentally. They result in front mass displacement saturation, drop in performances and instabilities. To interpret such features, a nonlinear approach is proposed. This resulting nonlinear model has been applied to the transducer and simulations are given. The comparison between numerical simulations and experimental results shows good agreement. Usually, observed saturation effects are interpreted as in term of viscous factor increase, our nonlinear approach gives an alternative explanation that explains also others observed phenomena. Des changements importants de comportement sont observés sur des transducteurs de puissance utilisant des céramiques de type PZT. Une meilleure caractérisation de matériaux piézoélectriques sous hauts niveaux s'avère alors nécessaire. En effet, des phénomèni caractéristiques d'un comportement non linéaire tels que le décalage de la fréquence de résonance avec hystérésis ou la génération d'harmoniques ont été observés expérimentalement. Ceci se traduit pax des effets de saturation du niveau de déplacement de la face avant, une limitation des performances du système et un fonctionnement instable. Afin d'interpréter de tels comportements, une théorie non linéaire est proposée. Ce modèle a ensuite été appliqué à notre structure de transducteur. Une comparaison entre simulations et résultats expérimentaux a permis de valider cette nouvelle approche. Les effets de saturation observés ont été jusqu'à présent toujours reliés à la variation du coefficient d'amortissement, notre étude a permis de démontrer qu'une autre explication liée aux non linéarités était possible et permettait en même temps d'expliquer d'autres phénomènes observés.

Guyomar, D.; Aurelle, N.; Eyraud, L.

1997-06-01

127

Application of gelcasting to the fabrication of piezoelectric ceramic parts  

Microsoft Academic Search

Gelcasting is a novel method for the molding of ceramic powder based on a synthesis of concepts derived from traditional ceramics and polymer chemistry. Although a wealth of literature has been published describing the application of the technology to the fabrication of structural ceramics, little has been reported about its application to the fabrication of functional ceramics. In order to

Dong Guo; Kai Cai; Longtu Li; Zhilun Gui

2003-01-01

128

High-power piezoelectric characteristics of textured bismuth layer structured ferroelectric ceramics.  

PubMed

Abstract-The high-power piezoelectric characteristics in h001i oriented ceramics of bismuth layer structured ferroelectrics (BLSF), SrBi(2)Nb(2)O(9) (SBN), (Bi,La)(4)Ti(3)O(12) (BLT), and CaBi(4)Ti(4)O(15) (CBT), were studied by a constant voltage driving method. These textured ceramics were fabricated by a templated grain growth (TGG) method, and their Lotgering factors were 95%, 97%, and 99%, respectively. The vibration velocities of the longitudinal mode (33-mode) increased proportionally to an applied electric field up to 2.5 m/s in these textured BLSF ceramics, although, the vibration velocity of the 33-mode was saturated at more than 1.0 m/s in the Pb(Mn,Nb)O(3)-PZT ceramics. The resonant frequencies were constant up to the vibration velocity of 2.5 m/s in the SBN and CBT textured ceramics; however, the resonant frequency decreased with increasing over the vibration velocity of 1.5 m/s in the BLT textured ceramics. The dissipation power density of the BLT was almost the same as that of the Pb(Mn,Nb)O(3)-PZT ceramics. However, the dissipation power densities of the SBN and CBT were lower than those of the BLT and Pb(Mn,Nb)O(3)-PZT ceramics. The textured SBN and CBT ceramics are good candidates for high-power piezoelectric applications. PMID:18276545

Ogawa, Hirozumi; Kawada, Shinichiro; Kimura, Masahiko; Shiratsuyu, Kousuke; Sakabe, Yukio

2007-12-01

129

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

SciTech Connect

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

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

2004-06-01

130

Radially composite piezoelectric ceramic tubular transducer in radial vibration.  

PubMed

The radially composite piezoelectric tubular transducer is studied. It is composed of radially poled piezoelectric and a long metal tube. The electro-mechanical equivalent circuit of the radially poled piezoelectric and metal tube in radial vibration is obtained. Based on the force and velocity boundary conditions, the six-port electro-mechanical equivalent circuit for the composite tubular transducer is given and the resonance/anti-resonance frequency equations are obtained. The relationship between the resonance frequency and the dimensions is analyzed. Numerically simulated results obtained by the finite element method are compared with those from the analytical method. Composite piezoelectric tubular transducers are designed and manufactured. The resonance/anti-resonance frequencies are measured, and it is shown that the theoretical results are in good agreement with the simulated and experimental results. It is expected that radially composite piezoelectric tubular transducers can be used as high-power ultrasonic radiators in ultrasonic applications, such as ultrasonic liquid processing. PMID:22083782

Shuyu, Lin; Shuaijun, Wang

2011-11-01

131

High-Power Piezoelectric Characteristics of Textured Bismuth Layer Structured Ferroelectric Ceramics  

Microsoft Academic Search

The high-power piezoelectric characteristics in c-axis oriented ceramics of bismuth layer structured ferroelectrics (BLSF), SrBi2Nb2O9 (SBN), Bi4Ti3O12 (BIT) and CaBi4Ti4O15 (CBT), were studied by constant voltage driving method. These textured ceramics were fabricated by templated grain growth (TGG) method, and their Lotgering factors were 95%, 97%, and 99%, respectively. The vibration velocities increased proportionally to an applied electric field up

H. Ogawa; S. Kawada; M. Kimura; K. Shiratsuyu; Y. Sakabe

2007-01-01

132

Adaptive grey control for hybrid resonant driving linear piezoelectric ceramic motor  

Microsoft Academic Search

This paper presents an adaptive grey control (AGC) system for a linear piezoelectric ceramic motor (LPCM) driven by a newly designed hybrid resonant inverter. First, the motor configuration and the driving circuit of an LPCM are introduced, and its hypothetical dynamic model is described briefly. The hybrid resonant drive system has the merits of high voltage gain from a parallel

Rong-Jong Wai; Ching-Hsiang Tu

2006-01-01

133

Optimized electrocaloric refrigeration capacity in lead-free (1-x)BaZr0.2Ti0.8O3-xBa0.7Ca0.3TiO3 ceramics  

NASA Astrophysics Data System (ADS)

This paper demonstrates the impact of composition on the electrocaloric effect in lead-free (1-x)BaZr0.2Ti0.8O3-xBa0.7Ca0.3TiO3 ceramics, especially on the morphotropic phase boundary. The samples exhibited typical diffused ferroelectric-paraelectric phase transition, which was diffused the most around the tricritical point of rhombohedral, tetragonal, and cubic phases at x = 0.3. The x = 0.3 sample had the highest ?Tmax of 0.30 K under 20 kV/cm field and the widest cooling peak within a wide composition range, which endowed it with the best refrigeration capacity. Although the x = 0.7 sample had even higher ?Tmax, less diffused phase transition narrowed the cooling peak, which reduced the refrigeration capacity.

Bai, Yang; Han, Xi; Qiao, Lijie

2013-06-01

134

Bending strength of piezoelectric ceramics and single crystals for multifunctional load-bearing applications.  

PubMed

The topic of multifunctional material systems using active or smart materials has recently gained attention in the research community. Multifunctional piezoelectric systems present the ability to combine multiple functions into a single active piezoelectric element, namely, combining sensing, actuation, or energy conversion ability with load-bearing capacity. Quantification of the bending strength of various piezoelectric materials is, therefore, critical in the development of load-bearing piezoelectric systems. Three-point bend tests are carried out on a variety of piezoelectric ceramics including soft monolithic piezoceramics (PZT-5A and PZT-5H), hard monolithic ceramics (PZT-4 and PZT-8), single-crystal piezoelectrics (PMN-PT and PMN-PZT), and commercially packaged composite devices (which contain active PZT-5A layers). A common 3-point bend test procedure is used throughout the experimental tests. The bending strengths of these materials are found using Euler-Bernoulli beam theory to be 44.9 MPa for PMN-PZT, 60.6 MPa for PMN-PT, 114.8 MPa for PZT- 5H, 123.2 MPa for PZT-4, 127.5 MPa for PZT-8, 140.4 MPa for PZT-5A, and 186.6 MPa for the commercial composite. The high strength of the commercial configuration is a result of the composite structure that allows for shear stresses on the surfaces of the piezoelectric layers, whereas the low strength of the single-crystal materials is due to their unique crystal structure, which allows for rapid propagation of cracks initiating at flaw sites. The experimental bending strength results reported, which are linear estimates without nonlinear ferroelastic considerations, are intended for use in the design of multifunctional piezoelectric systems in which the active device is subjected to bending loads. PMID:22711404

Anton, Steven R; Erturk, Alper; Inman, Daniel

2012-06-01

135

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

SciTech Connect

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

Upadhyay, Sanjay Kumar; Reddy, V. Raghavendra, E-mail: varimalla@yahoo.com, E-mail: vrreddy@csr.res.in; Bag, Pallab; Rawat, R. [UGC-DAE Consortium for Scientific Research, University Campus, Khandwa Road, Indore 452001 (India); Gupta, S. M. [Ceramic Laboratory, LMDDD, RRCAT, Indore 452013 (India); Gupta, Ajay [Amity Center for Spintronic Materials, Amity University, Noida 201303 (India)

2014-09-15

136

Lead Barium Potassium Sodium Niobate Ceramics for Piezoelectric Applications  

NASA Astrophysics Data System (ADS)

This paper reports a systematic study of tungsten bronze morphotropic phase boundary (MPB) system Pb2-2X-3Y/2Ba2xREyK1-xNaxNb5O15, where, x = 0.20, 0.25, 0.30, RE = Pr and Bi and y = 0.05 and their structure, microstructure, hysteresis, dielectric, piezoelectric, and Pyroelectric properties. Enhanced piezoelectric constants kp, kt, k31, d31, d33, g31, g33, S11 E as 30.8%, 47.6%, 18.9%, 57 × 10-12 C/N, 159 × 10-12 C/N, 6.89 × 10-3 mV/N, 19.23 × 10-3 mV/N, and 13.88 × 10-12 m2/N respectively are observed in the composition for which y = 0, and x = 0.30, which is above MPB. Also, a change in thickness, 0.0159 ?m has been developed for a thickness of the sample 1.2 mm, d33 = 159 × 10-12 C/N and for an applied voltage of 100 V. The same material produces a length extension, 0.0475 ?m for d31 = 57 × 10-12 C/N, l = 10 mm, t = 1.2 mm, for an applied voltage of 100 V. Thus the material may be useful for a piezoelectric transducer. Enhanced piezoelectric coefficients, d31 = 96 × 10-12 C/N and g33 = 12.95 × 10-3 mV/N are also observed in the composition for which RE = Pr and x = 0.25.

Sambasiva Rao, K.; Vallisnath, N.; Prasad, T. N. V. K. V.; Ch. Varada Rajulu, K.; Tilak, B.; Lee, Joon Hyung

137

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

NASA Technical Reports Server (NTRS)

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.

Hooker, Matthew W.

1998-01-01

138

High-power piezoelectric characteristics of textured bismuth layer structured ferroelectric ceramics  

Microsoft Academic Search

The high-power piezoelectric characteristics in (001) oriented ceramics of bismuth layer structured fer-roelectrics (BLSF), SrBi2Nb2O9 (SBN), (Bi,La)4Ti3O2 (BLT), and CaBi4Ti4Oi5 (CBT), were studied by a constant voltage driving method. These textured ceramics were fabricated by a templated grain growth (TGG) method, and their Lotgering factors were 95%, 97%, and 99%, respectively. The vibration velocities of the longitudinal mode (33-mode) increased

Hirozumi Ogawa; Shinichiro Kawada; Masahiko Kimura; Kousuke Shiratsuyu; Yukio Sakabe

2007-01-01

139

Flexural resonance vibrations of piezoelectric ceramic tubes in Besocke-style scanners  

NASA Astrophysics Data System (ADS)

Flexural resonance vibrations of piezoelectric ceramic tubes in Besocke-style scanners with nanometer resolution are studied by using an electro-mechanical coupling Timoshenko beam model. Meanwhile, the effects of friction, the first moment, and moment of inertia induced by mass loads are considered. The predicted resonance frequencies of the ceramic tubes are sensitive to not only the mechanical parameters of the scanners, but also the friction acting on the attached shaking ball and corresponding bending moment on the tubes. The theoretical results are in excellent agreement with the related experimental measurements. This model and corresponding results are applicable for optimizing the structures and performances of the scanners.

Zhang, Hui; Zhang, Shu-Yi; Fan, Li

2012-08-01

140

Anisotropy of piezoelectric properties in the modified PbTiO3 ceramics  

Microsoft Academic Search

This paper describes the crystal, dielectric and piezoelectric properties in the (Pb, Me) [(CO1\\/2W1\\/2), Ti]O3 system (Me=Ca, Sr, Ba). Among these materials, the Co-modified PbTi03 ceramics show a large anisotropy in the electromechanical coupling factor. The very small value o f the planar coupling factor may not be caused by the published existing mechanism such as the bulk property of

Noboru Ichinose; Youji Fuse

1990-01-01

141

Effects of static electric field on the fracture behavior of piezoelectric ceramics  

Microsoft Academic Search

The paper gives an overview on experimental observations of the failure behavior of electrically insulating and conducting\\u000a cracks in piezoelectric ceramics. The experiments include the indentation fracture test, the bending test on smooth samples,\\u000a and the fracture test on pre-notched (or pre-cracked) compact tension samples. For electrically insulating cracks, the experimental\\u000a results show a complicated fracture behavior under electrical and

Tong-Yi Zhang

2002-01-01

142

J. Phys. III Hance 7 (1997) 1197-1208 JUNE 1997, PAGE 1197 Piezoelectric Ceramics Nonlinear Behavior.  

E-print Network

PHYSIQUE III N°6 1. Introduction Piezoelectric ceramics, used in power transducers for sonars, ultrasonic transducers using PZT type of ceram- ics. A better characterization under high excitations is then required, first we present the nonlinearities induced in power transducer. Then we propose a theoretical

Paris-Sud XI, Université de

143

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

NASA Astrophysics Data System (ADS)

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

Wang, Jianhua; Xiao, Zexin

2011-11-01

144

Imaging of Acoustic Waves in Piezoelectric Ceramics by Coulomb Coupling  

NASA Astrophysics Data System (ADS)

The transport properties of bulk and guided acoustic waves travelling in a lead zirconate titanate (PZT) disc, originally manufactured to serve as ultrasonic transducer, have been monitored by scanned Coulomb coupling. The images are recorded by excitation and detection of ultrasound with local electric field probes via piezoelectric coupling. A narrow pulse has been used for excitation. Broadband coupling is achieved since neither mechanical nor electrical resonances are involved. The velocities of the traveling acoustic waves determined from the images are compared with characteristic velocities calculated from material properties listed by the manufacturer of the PZT plate.

Habib, Anowarul; Shelke, Amit; Pluta, Mieczyslaw; Kundu, Tribikram; Pietsch, Ullrich; Grill, Wolfgang

2012-07-01

145

Dielectric and piezoelectric properties of S001ceramics  

E-print Network

TiO3 ceramics Edward M. Sabolsky,a) Susan Trolier-McKinstry, and Gary L. Messing Materials Research Institute and Department of Materials Science and Engineering, The Pennsylvania State University, University. As previously stated, the enhanced electromechanical properties for the domain engineered materials have been

Messing, Gary L.

146

Lead-free primary explosives  

DOEpatents

Lead-free primary explosives of the formula (cat)Y[MII(T)X(H2O)6-X]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.

Huynh, My Hang

2010-06-22

147

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

SciTech Connect

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

Lu, Shengbo, E-mail: shengbo.lu@yahoo.com [Department of Physics and Materials Science, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon (Hong Kong); Department of Applied Physics and Materials Research Centre, The Hong Kong Polytechnic University, Hung Hom, Kowloon (Hong Kong); Xu, Zhengkui [Department of Physics and Materials Science, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon (Hong Kong); Kwok, K. W.; Chan, Helen L. W. [Department of Applied Physics and Materials Research Centre, The Hong Kong Polytechnic University, Hung Hom, Kowloon (Hong Kong)

2014-07-28

148

Transducer Performance for Leaky Wave in Layered Structure of Piezoelectric Ceramic Thin Plate and Acryl Plate  

NASA Astrophysics Data System (ADS)

A leaky wave transducer in the combination of a piezoelectric ceramic thin plate and an acryl plate is described, which functions as a transducer for underwater ultrasound. The operation performance of an interdigital transducer in the layered structure is described from the viewpoint of phase velocity, electromechanical coupling constant, mode conversion efficiency and transducer efficiency. The leaky wave transducer has multiple modes with velocity dispersion. Using the second-order anti-symmetrical mode with high transducer efficiency value, a liquid-delay line oscillation is demonstrated.

Toda, Kohji; Akutsu, Yasuhiko

1994-09-01

149

Network formalism for modeling functionally gradient piezoelectric plates and stacks and simulations of RAINBOW ceramic actuators.  

PubMed

A simple network representation is given for a stack of thin, homogeneous piezoelectric plates, executing a single thickness mode of motion. All plates may differ in thickness and material properties, including dielectric loss, ohmic conductivity, and viscous loss. Each plate is driven by a thickness-directed electric field, and all stack elements are connected electrically in series. Functionally gradient single plates and composites are readily modeled by the network, to a desired precision, using a sequence of circuit elements representing stepwise variations in material properties and layer thicknesses. Simulations of RAINBOW (Reduced And Internally Biased Oxide Wafer) ceramics are given. PMID:11370360

Ballato, J; Schwartz, R; Ballato, A

2001-03-01

150

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

SciTech Connect

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

Chen, Cheng-Sao, E-mail: rickchen@cc.hwh.edu.tw [Department of Mechanical Engineering, Hwa-Hsia Institute of Technology, New Taipei City 23567, Taiwan (China); Chen, Pin-Yi [Department of Mechanical Engineering, Ming-Chi University of Technology, New Taipei City 24301, Taiwan (China); Tu, Chi-Shun [Graduate Institute of Applied Science and Engineering, Fu Jen Catholic University, New Taipei City 24205, Taiwan (China)

2014-01-07

151

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

SciTech Connect

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

Luo, B. C. [School of Materials Science and Engineering, The University of New South Wales, Sydney, NSW 2052 (Australia) [School of Materials Science and Engineering, The University of New South Wales, Sydney, NSW 2052 (Australia); School of Science, Northwestern Polytechnical University, Xi'an 710072 (China); Wang, D. Y.; Li, S. [School of Materials Science and Engineering, The University of New South Wales, Sydney, NSW 2052 (Australia)] [School of Materials Science and Engineering, The University of New South Wales, Sydney, NSW 2052 (Australia); Duan, M. M. [School of Science, Northwestern Polytechnical University, Xi'an 710072 (China)] [School of Science, Northwestern Polytechnical University, Xi'an 710072 (China)

2013-09-16

152

Piezoelectric Properties of Sodium Bismuth Tantalate Na0.5Bi2.5Ta2O9 Dense Ceramics  

Microsoft Academic Search

The piezoelectric properties of sodium bismuth tantalate Na0.5Bi2.5Ta2O9 (NBTa) dense ceramics were determined using 0.1 wt% Mn-doped samples. The ferroelectric properties of the NBTa ceramics were confirmed. The remanent polarization Pr and coercive field Ec were 15.5 muC\\/cm2 and 81.5 kV\\/cm at room temperature, respectively. Optimum poling conditions (temperature Tp, time tp and electric field Ep) were investigated for piezoelectric

Mitsuhiro Matsushita; Rintaro Aoyagi; Hiroaki Takeda; Soichiro Okamura; Tadashi Shiosaki

2004-01-01

153

Phase coexistence and high electrical properties in (KxNa0.96-xLi0.04)(Nb0.85Ta0.15)O3 piezoelectric ceramics  

NASA Astrophysics Data System (ADS)

(KxNa0.96-xLi0.04)(Nb0.85Ta0.15)O3 lead-free piezoelectric ceramics were produced by conventional solid-state reaction method. The effects of K/Na ratio on the phase transitional behavior, Raman spectrum, microstructure, and dielectric, piezoelectric, and ferroelectric properties of the ceramics have been investigated. The phase structure of the ceramics undergoes a transition from orthorhombic to tetragonal phase with increasing x. A double-degenerate symmetric O-Nb-O stretching vibration v1 and a triply degenerate symmetric O-Nb-O bending vibration v5 are detected as relatively strong scattering in the Raman spectra. The peak shifts of v5 and v1 modes all have a discontinuity with x between 0.42 and 0.46, which may suggest the coexistence of orthorhombic and tetragonal phases in this range. Properly modifying x reduces the sintering temperature, promotes the grain growth behavior, and improves the density of the ceramics. The polymorphic phase transition (at To -t) is shifted to near room temperature by increasing x to 0.44 (K/Na ratio of about 0.85:1), and the coexistence of orthorhombic and tetragonal phases in the ceramics at x =0.44 results in the optimized electrical properties (d33=291 pC/N, kp=0.54, ?r=1167, tan ?=0.018, To -t=35 °C, TC=351 °C, Pr=27.65 ?C/cm2, and Ec=8.63 kV/cm). The results show that the equal K/Na ratio is not an essential condition in obtaining optimized electrical properties in (KxNa0.96-xLi0.04)(Nb0.85Ta0.15)O3 ceramics.

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

2009-03-01

154

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

NASA Astrophysics Data System (ADS)

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

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

2014-11-01

155

Characterization of piezoelectric ceramics and 1-3 composites for high power transducers  

NASA Astrophysics Data System (ADS)

The high power characteristics of various piezoelectric ceramics and 1-3 composites were investigated. In contrast to "hard" Pb(Zr,Ti)O3, modified (Bi0.5Na0.5)TiO3 based ceramics were found to show a relatively linear electromechanical response under high drive conditions due to their high stability of mechanical quality factor. The effects of high drive field and duty cycle on the behavior of 1-3 composites were analyzed by varying active and passive components. Improved high power characteristics of 1-3 composites were achieved by selection of optimized composite components, with enhanced electromechanical efficiency and thermal stability under high drive conditions.

Jae Lee, Hyeong; Zhang, Shujun; Meyer, Richard J.; Sherlock, Nevin P.; Shrout, Thomas R.

2012-07-01

156

Characterization of piezoelectric ceramics and 1-3 composites for high power transducers  

PubMed Central

The high power characteristics of various piezoelectric ceramics and 1-3 composites were investigated. In contrast to “hard” Pb(Zr,Ti)O3, modified (Bi0.5Na0.5)TiO3 based ceramics were found to show a relatively linear electromechanical response under high drive conditions due to their high stability of mechanical quality factor. The effects of high drive field and duty cycle on the behavior of 1-3 composites were analyzed by varying active and passive components. Improved high power characteristics of 1-3 composites were achieved by selection of optimized composite components, with enhanced electromechanical efficiency and thermal stability under high drive conditions. PMID:22893730

Jae Lee, Hyeong; Zhang, Shujun; Meyer, Richard J.; Sherlock, Nevin P.; Shrout, Thomas R.

2012-01-01

157

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

NASA Technical Reports Server (NTRS)

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

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

2011-01-01

158

Electric properties of Holmium substituted SrBi4Ti4O15ceramic for High Temperature Piezoelectric Applications  

Microsoft Academic Search

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

P. Sarah

2011-01-01

159

Antiplane mechanical and inplane electric time-dependent load applied to two coplanar cracks in piezoelectric ceramic material  

Microsoft Academic Search

This work is concerned with the dynamic response of two coplanar cracks in a piezoelectric ceramic under antiplane mechanical and inplane electric time-dependent load. The cracks are assumed to act either as an insulator or as a conductor. Laplace and Fourier transforms are used to reduce the mixed boundary value problems to Cauchy-type singular integral equations in Laplace transform domain.

Z. T. Chen; M. J. Worswick

2000-01-01

160

Effect of electrical and mechanical poling history on domain orientation and piezoelectric properties of soft and hard PZT ceramics  

NASA Astrophysics Data System (ADS)

The superior piezoelectric properties of all polycrystalline ferroelectrics are based on the extent of non-180° domain wall motion under electrical and mechanical poling loads. To distinguish between 180° and non-180° domain wall motion in a soft-doped and a hard-doped lead zirconate titanate (PZT) ceramic, domain texture measurements were performed using x-ray and neutron diffraction after different loading procedures. Comparing the results to measurements of the remanent strain and piezoelectric coefficient allowed the differentiation between different microstructural contributions to the macroscopic parameters. Both types of ceramic showed similar behavior under electric field, but the hard-doped material was more susceptible to mechanical load. A considerable fraction of the piezoelectric coefficient originated from poling by the preferred orientation of 180° domains.

Marsilius, Mie; Granzow, Torsten; Jones, Jacob L.

2011-02-01

161

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

PubMed Central

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

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

2013-01-01

162

New, lead-free solders  

NASA Astrophysics Data System (ADS)

Two specific examples of the new lead-free alloys are described. In the Sn-3.5%Ag-l%Zn alloy (m.p.~217°C), the eutectic precipitate morphology is refined by the relatively small amount of zinc addition and as a result, a high-strength, high-ductility solder with significantly improved creep resistance is obtained. As a temperature equivalent drop-in replacement for the Pb-Sn eutectic alloy (m.p.~183°C), Sn-Zn-In based alloys (m.p.~185°C) have been developed. The addition of indium to the Sn-Zn binary system improves the wetting characteristics of the alloy and lowers the melting temperature.

McCormack, M.; Jin, S.

1994-07-01

163

Ferroelectric and piezoelectric properties of vanadium-doped CaBi 4Ti 4O 15 ceramics  

Microsoft Academic Search

Vanadium-doped CaBi4Ti4O15 (CBTVx, x=0?0.2) bismuth layered structure ferroelectric (BLSF) ceramics were prepared by the solid-state reaction method. X-ray diffraction pattern showed that single phase of BLSF with m=4 formed when x?0.1. The sintering temperature of the CaBi4Ti4O15 ceramics was lowered by doping of vanadium. The effects of vanadium doping on the dielectric, ferroelectric and piezoelectric properties of CaBi4Ti4?xVx ceramics were

Jiangtao Zeng; Yongxiang Li; Qunbao Yang; Qingrui Yin

2005-01-01

164

Electromechanical Properties of A-Site (LiHo)Modified Strontium Bismuth Titanate (SrBi4Ti4O15) Piezoelectric Ceramics  

Microsoft Academic Search

The Aurivillius-type bismuth layer-structure Sr0.84(LiHo)0.08Bi4Ti4O15 (SBT-LiHo) piezoelectric ceramics were synthesized using conventional solid state processing. Phase analysis was performed by X-ray diffraction (XRD). The dielectric, piezoelectric, ferroelectric, and electromechanical properties of SBT-LiHo ceramics were investigated. The piezoelectric activities were found to be significantly enhanced compared to SrBi4Ti4O15 (SBT) ceramics, which can be attributed to the lattice distortion and the presence

B. Mamatha; A. R. James; P. Sarah

2011-01-01

165

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

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

166

A piezoelectric plethysmograph sensor based on a Pt wire implanted lead lanthanum zirconate titanate bulk ceramic.  

PubMed

This work reports on the development of a Lead Lanthanum Zirconate Titanate (PLZT) bulk ferroelectric poled ceramic structure as a Piezoelectric Plethysmograph (PZPG) sensor. The ceramic was implanted during its fabrication with a platinum (Pt) wire which works as an internal electrode. The ceramic was then submitted to an experimental setup in order to validate and determine the Pt-wire mechanical effects. This PZPG sensor was also mounted on a finger splint in order to measure the blood flow that results from the pulsations of blood occurring with each heartbeat. Fingertip pulses were recorded jointly with an ECG signal from a 25 year old male to compare the time shift; the PZPG sensor guarantees the electrical isolation of the patient. The proposed PZPG has several advantages: it can be adjusted for fingertip measurements, but it can easily be extended by means of spare bands, therefore making possible PZPG measurements from different body locations, e.g., forehead, forearm, knee, neck, etc. PMID:22163596

González-Morán, Carlos O; Flores-Cuautle, J J Agustín; Suaste-Gómez, Ernesto

2010-01-01

167

A Piezoelectric Plethysmograph Sensor Based on a Pt Wire Implanted Lead Lanthanum Zirconate Titanate Bulk Ceramic  

PubMed Central

This work reports on the development of a Lead Lanthanum Zirconate Titanate (PLZT) bulk ferroelectric poled ceramic structure as a Piezoelectric Plethysmograph (PZPG) sensor. The ceramic was implanted during its fabrication with a platinum (Pt) wire which works as an internal electrode. The ceramic was then submitted to an experimental setup in order to validate and determine the Pt-wire mechanical effects. This PZPG sensor was also mounted on a finger splint in order to measure the blood flow that results from the pulsations of blood occurring with each heartbeat. Fingertip pulses were recorded jointly with an ECG signal from a 25 year old male to compare the time shift; the PZPG sensor guarantees the electrical isolation of the patient. The proposed PZPG has several advantages: it can be adjusted for fingertip measurements, but it can easily be extended by means of spare bands, therefore making possible PZPG measurements from different body locations, e.g., forehead, forearm, knee, neck, etc. PMID:22163596

González-Morán, Carlos O.; Flores-Cuautle, J.J. Agustín; Suaste-Gómez, Ernesto

2010-01-01

168

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

NASA Astrophysics Data System (ADS)

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 Young’s modulus and Poisson’s ratio. With increasing firing temperature, the longitudinal and transverse wave velocities increased; as a result, Young’s modulus increased because of BT ceramics being mechanically hard. Poisson’s 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 Young’s modulus and Poisson’s ratio after DC poling compared with those before DC poling, that is, lowering Young’s modulus and increasing Poisson’s 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.

Ogawa, Toshio; Ikegaya, Taiki

2015-01-01

169

The Dielectric and Electric Characteristics of Piezoelectric Ceramics for Ultrasonic Oscillator Application  

NASA Astrophysics Data System (ADS)

The application of the ultrasonic nozzle has been extended because it can atomize liquid material. In this study, the characteristics of the ultrasonic nozzle and ceramic oscillator were investigated. The oscillator for the ultrasonic nozzle is made of piezoelectric ceramic of Pb[(Sb1/2Nb1/2)0.035, (Mn1/3Nb2/3)0.065, (ZrxTi1-x)0.90O3 The electromechanical coupling factor (kp) and mechanical quality factor (Qm) were 0.555 and 1,214, respectively, when the Zr/Ti ratio was 49/51. Moreover, this oscillator will have temperature stability because its curie temperature is 322. The driving current of the ultrasonic nozzle was 80 mA, when the driving time was 10 min. Also, the surface temperature of the ceramic oscillator was 80 at a driving time of 10 min. We discovered that the ultrasonic nozzle will be subjected to stable driving after 10 min.

Lee, Su-Ho; Yoo, Ju-Hyun; Yoon, Kwang-Hee; Sug, Joung-Young; Rue, Gi-Hong; Sin, Kwang-Ho; Kim, Jin-Gyu; Hong, Jae-Il

2002-11-01

170

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

NASA Astrophysics Data System (ADS)

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.

Ma, Fengde D.; Wang, Yu U.

2015-03-01

171

Robust solder joint attachment of coaxial cable leads to piezoelectric ceramic electrodes  

SciTech Connect

A technique was developed for the solder attachment of coaxial cable leads to the silver-bearing thick film electrodes on piezoelectric ceramics. Soldering the cable leads directly to the thick film caused bonds with low mechanical strength due to poor solder joint geometry. A barrier coating of 1.5 {mu}m Cu/1.5 {mu}m Ni/1.0{mu}m Sn deposited on the thick film layer improved the strength of the solder joints by eliminating the absorption of Ag from the thick film which was responsible for the improper solder joint geometry. The procedure does not require special preparation of the electrode surface and is cost effective due to the use of non-precious metal films and the batch processing capabilities of the electron beam deposition technique.

Vianco, P.T.

1992-01-01

172

Robust solder joint attachment of coaxial cable leads to piezoelectric ceramic electrodes  

SciTech Connect

A technique was developed for the solder attachment of coaxial cable leads to the silver-bearing thick film electrodes on piezoelectric ceramics. Soldering the cable leads directly to the thick film caused bonds with low mechanical strength due to poor solder joint geometry. A barrier coating of 1.5 {mu}m Cu/1.5 {mu}m Ni/1.0{mu}m Sn deposited on the thick film layer improved the strength of the solder joints by eliminating the absorption of Ag from the thick film which was responsible for the improper solder joint geometry. The procedure does not require special preparation of the electrode surface and is cost effective due to the use of non-precious metal films and the batch processing capabilities of the electron beam deposition technique.

Vianco, P.T.

1992-08-01

173

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

SciTech Connect

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

Venkata Ramana, E., E-mail: venkataramanaesk@rediffmail.com [I3N-Aveiro, Department of Physics, University of Aveiro, Aveiro 3810 193 (Portugal); Mahajan, A. [Department of Materials and Ceramics Engineering, University of Aveiro, Aveiro 3810 193 (Portugal); Graça, M.P.F.; Mendiratta, S.K.; Monteiro, J.M.; Valente, M.A. [I3N-Aveiro, Department of Physics, University of Aveiro, Aveiro 3810 193 (Portugal)

2013-10-15

174

Piezoelectric and Mechanical Properties of BaBi4Ti4O15\\/Ba4Ti13O30 Ceramics  

Microsoft Academic Search

This article presents the piezoelectric and mechanical properties of bismuth layer-structured ferroelectrics (BLSF)-based BaBi4Ti4O15 ceramics incorporating Ba4Ti13O30. The ceramic compositions, (1-x)BaBi4Ti4O15 xBa4Ti13O30 with x=0 100 vol%, are obtained through solid-state reaction processes. The dielectric constant, ?33T\\/?0, decreases exponentially from 220 to 97 with increasing x from 0 to 66 vol%. The electromechanical coupling factor, k33, decreases from 15 to 7%

Yasuhiro Nakai; Shuichi Fukuoka

1999-01-01

175

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

PubMed

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

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

2012-09-01

176

Composition Design Rule for High Piezoelectric Voltage Coefficient in (K0.5Na0.5)NbO3 Based Pb-Free Ceramics  

NASA Astrophysics Data System (ADS)

In this manuscript, the phase transition factor (Ft) was suggested as a design rule for high piezoelectric voltage coefficient in (K0.5Na0.5)NbO3 (KNN) based ceramics. The Ft consisted of the tolerance factor and electronegativity difference. High piezoelectric voltage coefficient was observed when the doping ratio for the starting point of phase transition (x*) was higher than 0.04 in KNN based ceramics. At the range of Ft < -0.01, x* was higher than 0.04 and high g33 value (>30 mV·m/N) was observed in KNN based ceramics.

Ahn, Cheol-Woo; Han, Guifang; Ryu, Jungho; Yoon, Woon-Ha; Choi, Jong-Jin; Hahn, Byung-Dong; Kim, Jong-Woo; Choi, Joon-Hwan; Park, Dong-Soo

2012-09-01

177

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

NASA Astrophysics Data System (ADS)

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

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

2012-05-01

178

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

NASA Astrophysics Data System (ADS)

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

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

2015-02-01

179

Dielectric behavior and impedance analysis of lead-free CuO doped (Na0.50K0.50)0.95(Li0.05Sb0.05Nb0.95)O3 ceramics  

NASA Astrophysics Data System (ADS)

Pure (Na0.50K0.50)0.95(Li0.05Sb0.05Nb0.95)O3 (NKNLS) and CuO doped NKNLS perovskite structured ferroelectric ceramics were prepared by the solid-state reaction method. x wt% of CuO (x = 0.2-0.8 wt%) was added in the NKNLS ceramics. X-ray diffraction patterns indicate that single phase was formed for pure NKNLS while a small amount of second phase (K6Li4Nb10O30 ˜ 3%) was present in Cu2+ doped NKNLS ceramics. Dielectric anomalies around the temperatures of 120 °C and 350 °C have been identified as the ferroelectric-paraelectric transition (orthorhombic to tetragonal and tetragonal to cubic) temperatures for pure NKNLS compound. The electrical behavior of the ceramics was studied by impedance study in the high temperature range. Impedance analysis has shown the grain and grain boundary contribution using an equivalent circuit model. The impedance response in pure and Cu2+ doped NKNLS ceramics could be resolved into two contributions, associated with the bulk (˜grains) and the grain boundaries. From the conductivity studies, it is found that activation energies are strongly frequency dependent. The activation energy obtained from dielectric relaxation data may be attributed to oxygen ion vacancies.

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

2013-03-01

180

Combinatorial processing libraries for bulk BiFeO3-PbTiO3 piezoelectric ceramics  

NASA Astrophysics Data System (ADS)

A high throughput approach for generating combinatorial libraries with varying processing conditions for bulk ceramics has been developed. This approach utilized the linear temperature gradient in a tube furnace to screen a whole temperature range for optimized preparation. With this approach, the processing of 0.98[0.6BiFeO3-0.4PbTiO3]-0.02Pb(Mg1/3Nb2/3)O3 ceramic powders and pellets for high-temperature piezoelectric applications was demonstrated to identify the best synthesis conditions for phase purity. The dielectric property measurement on the as-processed solid solution ceramics confirmed the high Curie temperature and the improved loss tangent with the Pb(Mg1/3Nb2/3)O3 doping.

Hu, W.; Tan, X.; Rajan, K.

2010-05-01

181

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

PubMed

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

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

2004-11-01

182

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

PubMed

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

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

2001-07-01

183

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

NASA Astrophysics Data System (ADS)

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

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

2010-04-01

184

NASA DOD Lead Free Electronics Project  

NASA Technical Reports Server (NTRS)

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

Kessel, Kurt R.

2008-01-01

185

Fabrication and Piezoelectric Properties of Textured (Bi1/2K1/2)TiO3 Ferroelectric Ceramics  

NASA Astrophysics Data System (ADS)

Textured (Bi1/2K1/2)TiO3 (BKT) ceramics were prepared by a reactive templated grain growth (RTGG) method to improve their piezoelectric properties. Also, a hot-pressing (HP) method was modified on the basis of RTGG method to obtain dense ceramics and promote the grain orientation. The textured BKT ceramics prepared by the RTGG and HP methods exhibited a relatively high orientation factor F of 0.82 and a high density ratio of 95-99%. Scanning electron microscopy (SEM) micrographs of the textured HP-BKT indicated a textured and poreless microstructure. In addition, the resistivity of the textured HP-BKT was 1.73×1013 ?·cm. The piezoelectric strain constant d33 determined by means of resonance and antiresonance method was 125 pC/N for the direction parallel to the sheet-stacking direction of the RTGG process. From the measurement of field-induced stain, the normalized d33* (=Smax/Emax) at 80 kV/cm were 127 and 238 pm/V on the randomly oriented and textured samples (F=0.82) for the (?) direction, respectively.

Nagata, Hajime; Saitoh, Masahiro; Hiruma, Yuji; Takenaka, Tadashi

2010-09-01

186

Piezoelectric Ultrasonic Micromotors  

E-print Network

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

Flynn, Anita M.

1995-06-01

187

Ferroelectric, Piezoelectric and Pyroelectric Properties of Sr1+xBi4-xTi4-xTaxO15 Ceramics (x=0-1)  

Microsoft Academic Search

The dielectric, ferroelectric, piezoelectric and pyroelectric properties of bismuth layer-structured ferroelectric (BLSF) Sr1+xBi4-xTi4-xTaxO15 (x=0-1) ceramics were investigated. The Curie temperature of this system is from 540°C to 30°C, and all samples show ferroelectricity at room temperature. From piezoelectric measurements, Sr1.1Bi3.9Ti3.9Ta0.1O15 was found to have the largest piezoelectric coefficient and electromechanical coupling factor of compounds in this system. The thermally stimulated

Minglei Zhao; Chunlei Wang; Weilie Zhong; Jinfeng Wang; Hongcun Chen

2002-01-01

188

Phase-transformation-induced microstructure in lead-free ferroelectric ceramics based on (Bi0.5Na0.5)TiO3--BaTiO3--(Bi0.5K0.5)TiO3  

Microsoft Academic Search

Lead-free ferroelectric ceramics with a morphotropic phase boundary (MPB) composition 85.4% (Bi0.5Na0.5)TiO3–2.6%BaTiO3–12.0% (Bi0.5K0.5)TiO3 (BNT-BT-BKT at a molar ratio of 85.4: 2.6: 12.0) doped with 0.8?mol% Nb2O5 were studied for their crystalline phases and microstructure. The crystalline phases were identified using X-ray diffractometry (XRD) with the contents determined using the Rietveld refinement technique. The phase-transformation-induced microstructure was analyzed using transmission electron

Shun-Yu Cheng; Jay Shieh; New-Jin Ho; Hong-Yang Lu

2011-01-01

189

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

NASA Astrophysics Data System (ADS)

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

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

2014-09-01

190

Enhanced High Temperature Piezoelectrics Based on BiScO3-PbTiO3 Ceramics  

NASA Technical Reports Server (NTRS)

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

Sehirlioglu, Alp; Sayir, Ali; Dynys, Fred

2009-01-01

191

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

NASA Astrophysics Data System (ADS)

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

Zong, Ximei; Yang, Zupei

2015-01-01

192

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

NASA Astrophysics Data System (ADS)

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

Pal, Vijayeta; Dwivedi, R. K.

2015-02-01

193

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

SciTech Connect

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

Zhao Tianlong [Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing 100871 (China); School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100 (China); Chen Jianguo; Dong Shuxiang [Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing 100871 (China); Wang Chunming [School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100 (China); Yu Yang [Faculty of Physics and Electronic Technology, Hubei University, Wuhan 430062 (China)

2013-07-14

194

Interface failure in lead free solder joints  

Microsoft Academic Search

The phenomenon of interface failure in lead free solder joints was explored using solder joint array tensile testing. The effects of pad metallization, solder alloy, reflow conditions, and post reflow thermal aging were quantified. The joint strength ranged from 5 to 115MPa. The joint ductility dropped to zero in some cases. The interface microstructure and failure mode were characterized for

Robert Darveaux; Corey Reichman; Nokibul Islam

2006-01-01

195

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)

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.

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

2014-01-01

196

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

SciTech Connect

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

Vats, Gaurav; Vaish, Rahul, E-mail: rahul@iitmandi.ac.in [School of Engineering, Indian Institute of Technology Mandi, Himachal Pradesh 175 001 (India); Bowen, Chris R. [Department of Mechanical Engineering, Materials Research Centre, University of Bath, Bath BA2 7AY (United Kingdom)

2014-01-07

197

Accelerated Aging of Lead-Free Propellant  

NASA Technical Reports Server (NTRS)

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

Furrow, Keith W.; Jervey, David D.

2000-01-01

198

Morphotropic phase boundary in (1-x)Bi0.5Na0.5TiO3-xK0.5Na0.5NbO3 lead-free piezoceramics  

NASA Astrophysics Data System (ADS)

The electromechanical behavior of (1-x)Bi0.5Na0.5TiO3-xK0.5Na0.5NbO3 (BNT-KNN) lead free piezoelectric ceramics is investigated for 0?x?0.12 to gain insight into the antiferroelectric-ferroelectric (AFE-FE) phase transition on the basis of the giant strain recently observed in BNT-based systems. At x ?0.07, a morphotropic phase boundary (MPB) between a rhombohedral FE phase and a tetragonal AFE phase is found. While the piezoelectric coefficient is largest at this MPB, the total strain further increases with increasing KNN content, indicating the field-induced AFE-FE transition as the main reason for the large strain.

Kounga, Alain Brice; Zhang, Shan-Tao; Jo, Wook; Granzow, Torsten; Rödel, Jürgen

2008-06-01

199

Measurements of Complex Piezoelectric d33 Constant in Ferroelectric Ceramics under High Electric Field Driving  

Microsoft Academic Search

A measurement system has been designed and constructed which is capable of automatic data collection for complex piezoelectric d33 constant (amplitude and phase), field-induced polarization and switching current under high electric field driving in ferroelectric materials. The system is based on the direct piezoelectric effect and d33 constant can be measured down to about 10 pC\\/N. Using this system, low

Yasuyoshi Saito

1995-01-01

200

Piezoelectric and Mechanical Properties of BaBi4Ti4O15/Ba4Ti13O30 Ceramics  

NASA Astrophysics Data System (ADS)

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

Nakai, Yasuhiro; Fukuoka, Shuichi

1999-09-01

201

Processing and enhanced piezoelectric properties of highly oriented compositionally modified Pb(Zr,Ti)O3 ceramics fabricated by magnetic alignment  

NASA Astrophysics Data System (ADS)

Highly oriented compositionally modified Pb(Zr,Ti)O3 (PZT) ceramics were successfully obtained by slip casting in a high magnetic field. PZT is a well-known superior ceramic with the highest piezoelectric properties, and these properties have been expected to be further improved through crystalline orientation. However, highly oriented PZT ceramics fabricated by slip casting in a high magnetic field have never been reported. We obtained oriented ceramics using compositionally modified PZT with Pb(Ni,Nb)O3, and their Lotgering factor was 0.77. The electromechanical coupling coefficient (k31) increased by 30%, and an extremely high value of 0.44 was achieved for the oriented ceramics.

Miwa, Yasunari; Kawada, Shinichiro; Kimura, Masahiko; Omiya, Suetake; Kubodera, Noriyuki; Ando, Akira; Suzuki, Tohru S.; Uchikoshi, Tetsuo; Sakka, Yoshio

2015-04-01

202

A novel technique for preparation of grain oriented BLSF piezoelectric ceramics  

Microsoft Academic Search

Grain oriented bismuth layer-structured ferroelectrics (BLSFs) ceramics CaBi4Ti3.95V0.05O15 were prepared by screen-printing method. The particle size of starting materials is a very important factor for the grain\\u000a orientation annealed ceramics. Highly textured ceramics can only be obtained by using nanosized TiO2 and the mechanism for grain orientation was proposed. The electrical properties of the textured ceramics showed strongly\\u000a anisotropic. The

Yongxiang Li; Jiangtao Zeng; Xuezhen Jing; Qingrui Yin

2008-01-01

203

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

NASA Astrophysics Data System (ADS)

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.

Mukherjee, Binu

2008-07-01

204

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

NASA Astrophysics Data System (ADS)

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.

Toda, Kohji; Sawaguchi, Akihiro

1991-01-01

205

Influence of gallium substitutions on the structure, dielectric and piezoelectric properties of BiScO3-PbTiO3 ceramics  

NASA Astrophysics Data System (ADS)

Ceramics with compositions close to the morphotropic boundary in the (1 - x)Bi(Sc1-yGay)O3-xPbTiO3 system were prepared by the conventional solid-state reaction method. The influence of substituting Ga3+ cations for Sc3+ cations on the structural parameters and the dielectric and piezoelectric properties was studied. It was proved that variations in the relative content of the tetragonal and rhombohedral phases depended on the tolerance-factor t value determined by the B-cation substitutions. The highest values of the piezoelectric coefficient d33 were observed in the compositions with the largest proportion of the tetragonal phase.

Politova, E. D.; Kaleva, G. M.; Mosunov, A. V.; Segalla, A. H.

2014-04-01

206

Simple model for piezoelectric ceramic\\/polymer 1-3 composites used in ultrasonic transducer applications  

Microsoft Academic Search

A theoretical model is presented for combining parameters of 1-3 ultrasonic composite materials in order to predict ultrasonic characteristics such as velocity, acoustic impedance, electromechanical coupling factor, and piezoelectric coefficients. Hence, the model allows the estimation of resonance frequencies of 1-3 composite transducers. This model has been extended to cover more material parameters, and they are compared to experimental results

H. L. W. Chan; JOSEPH UNSWORTH

1989-01-01

207

New design method of piezoelectric transformer considering high-power characteristics of various composition ceramics  

Microsoft Academic Search

Newly developed design method of the piezoelectric transformer for high voltage source is described. In the method, high power characteristics are utilized for estimating the efficiency and the voltages and electric powers at the input and output terminals, and also the capacitance component of the load impedance is considered. The authors already investigated the high power characteristics on many kinds

S. Hirose; N. Takita; S. Takahashi

1998-01-01

208

Shear deformation of lead free solder joints  

Microsoft Academic Search

The deformation behavior of lead free solder joints was characterized under shear loading. The test vehicle was a 0.5mm pitch wafer level chip scale package (WLCSP). Five alloys were compared: Sn63Pb37, Sn95.5Ag4.0Cu0.5, Sn96.5Ag3.0Cu0.5, Sn96.5Ag3.5, and Sn99.3Cu0.7. The strain rate range was between 1.0\\/sec and 10-7\\/sec, and test temperature was 25C. Both un-aged and thermally aged samples were tested. The aging

Robert Darveaux

2005-01-01

209

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

SciTech Connect

(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.

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

210

Ferroelectric, Piezoelectric and Pyroelectric Properties of Sr1+xBi4-xTi4-xTaxO15 Ceramics (x=0-1)  

NASA Astrophysics Data System (ADS)

The dielectric, ferroelectric, piezoelectric and pyroelectric properties of bismuth layer-structured ferroelectric (BLSF) Sr1+xBi4-xTi4-xTaxO15 (x=0-1) ceramics were investigated. The Curie temperature of this system is from 540°C to 30°C, and all samples show ferroelectricity at room temperature. From piezoelectric measurements, Sr1.1Bi3.9Ti3.9Ta0.1O15 was found to have the largest piezoelectric coefficient and electromechanical coupling factor of compounds in this system. The thermally stimulated current measurements showed that Sr1.1Bi3.9Ti3.9Ta0.1O15 also has excellent pyroelectric responses, and the enhancement of pyroelectric properties may partially result from a relatively large temperature-dependent internal electric field which was observed from the polarization-electric field (P-E) hysteresis loops.

Zhao, Minglei; Wang, Chunlei; Zhong, Weilie; Wang, Jinfeng; Chen, Hongcun

2002-03-01

211

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

Microsoft Academic Search

The most characteristic narrow-band transducer structure for high-power ultrasonic applications is the well known piezoelectric sandwich which is reminiscent of the Langevin transducer. Such structure is generally used jointly with other components in the construction of industrial high-power transducers.One of the main objectives in the design and construction of such high-power transducers is to minimize energy losses. To that purpose

D. Chacón; G. Rodr?´guez-Corral; L. Gaete-Garretón; E. Riera-Franco de Sarabia; J. A. Gallego-Juárez

2006-01-01

212

Piezoelectric properties and structural characterization of (Na,Bi)Bi2Ta2O9 ceramics with bismuth layer-structure  

Microsoft Academic Search

The piezoelectric properties of bismuth layer-structured ferroelectrics Na0.5-xBi0.5+x3\\/Bi2Ta2O9 (NBT(x)) dense ceramics were investigated, and the crystal structure of synthesized NBT(x) powders was analyzed by the Rietveld method. NBT(x) powder and ceramics were prepared by conventional synthesis method. NBT(x) powder for x = 0 and x = 0.1 was confirmed to be single phase of BLSFs (m = 2) by x-ray

R. Aoyagi; M. Matsushita; K. Komagata; H. Takeda; S. Okamura; T. Shiosaki

2002-01-01

213

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

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

214

Processing of Piezoelectric (Li,Na,K)NbO3 Porous Ceramics and (Li,Na,K)NbO3/KNbO3 Composites  

NASA Astrophysics Data System (ADS)

Porous Li0.06(Na0.5K0.5)0.94NbO3 (LNKN-6) ceramics with different pore volumes have been prepared using preceramic powder and phenol resin fiber (KynolTM) as a pore former. It was confirmed that the porous ceramics synthesized by the “two-stage firing method” suppressed the loss of alkali elements from the porous body during heat treatment. The porous LNKN-6 ceramics were then converted to LNKN-6/KNbO3 composites through soaking and heat treatment using a sol-gel precursor source composed of KNbO3 to form 3-3-type composites. The microstructure, dielectric, and piezoelectric properties of the porous LNKN-6 ceramics and LNKN-6/KNbO3 composites were characterized and compared. The LNKN-6/KNbO3 composites had a hollow structure whose pores in the region near the surface were filled and coated with KNbO3 precipitates; however, a large amount of residual air was trapped in the pores inside the composites. As a result, the LNKN-6/KNbO3 composites fabricated using 30 vol % KynolTM showed an enhanced piezoelectric voltage output coefficient (g33) of 63.0× 10-3 V\\cdotm/N, compared with monolithic LNKN-6 ceramics having a g33 of 30.2× 10-3 V\\cdotm/N.

Kakimoto, Ken-ichi; Imura, Tomoya; Fukui, Yasuchika; Kuno, Masami; Yamagiwa, Katsuya; Mitsuoka, Takeshi; Ohbayashi, Kazushige

2007-10-01

215

Temperature dependent properties and poling effect of K4CuNb8O23 modified (Na0.5K0.5)NbO3 lead free piezoceramics  

NASA Astrophysics Data System (ADS)

Lead free piezoelectric ceramics (Na0.5K0.5)NbO3 modified by 4% mol. K4CuNb8O23 (abbreviated NKN:4KCN hereinafter) contain moderate piezoelectric constant d33 ˜ 100 pC N-1 and large mechanical quality factor Qm > 1000, showing possible replacement of the lead-based ones (Chen et al., J Appl. Phys. 102, 104109 (2007)). In terms of practical use, however, the temperature stability of NKN:4KCN is not clear to date. We made a systematic investigation on the properties versus temperature of NKN:4KCN to evaluate whether it can be practically used. In the range from room temperature (RT ˜ 25 °C) to 100 °C, the ferroelectricity of poled NKN:4KCN material is nearly temperature independent, remanent polarization Pr is about 27.6 ±1 ?C cm-2. When the as-studied NKN:4KCN ceramics were thermal depolarized in temperature range from RT to 450 °C, piezoelectric constant d33 changed little, retaining about 99 pC N-1, 77 ± 3 pC N-1, from RT to 150 °C, 200 °C to 350 °C, respectively. The poled NKN:4KCN material showed higher orthorhombic to tetragonal phase transition temperature (TO-T ˜ 200 °C) compared to unpoled sample (TO-T ˜ 194 °C). Moreover, this kind of lead free material displayed negative temperature coefficient of frequency (TCF) and positive TCF in orthorhombic and tetragonal phase state, respectively. The TCF was about -360 ppm K-1 in the range from RT to 125 °C, close to some lead-based commercial ones. The significance of this work lies in evaluating whether such a material can be practically used or not. We believe such a material might be the most promising candidate for replacing lead-based ones in some areas in the future.

Chen, Qiang; Chen, Yu; Peng, Zhihang; Wu, Jiagang; Liu, Hong; Xiao, Dingquan; Yu, Ping; Zhu, Jiliang; Zhu, Jianguo

2015-03-01

216

Piezoelectric and pyroelectric properties of calcium-modified and grain-oriented (NaBi)1\\/2Bi4Ti4O15 ceramics  

Microsoft Academic Search

Grain orientation effects of (NaBi)(l-x)\\/2CaxBi4Ti4O15 (NCBT-100x) ceramics, which belong to a bismuth layer-structured ferroelectric (BLSF) family, are studied using the hot-forging (H.F.) method on the piezoelectric and pyroelectric properties. The dielectric constant ?s is small and almost constant at the wide range of composition (x = 0tox = 1). The Curie temperature, Tc, increases as the Ca concentration increases. The

T. Takenaka; K. Sakata

1989-01-01

217

Piezoelectric and dielectric properties of Sn-doped (Na0.5K0.5)NbO3 ceramics processed under low oxygen partial pressure atmosphere  

NASA Astrophysics Data System (ADS)

Sn-doped (Na0.5K0.5)NbO3 (Sn-NKN) ceramics fired under various oxygen partial pressure (pO2) conditions have been investigated and discussed in terms of bulk piezoelectric and dielectric properties. X-ray diffraction measurements and Rayleigh analysis indicate that the substitution site of the Sn cations depend on the pO2 atmosphere in the firing process. For pO2 higher than 1.0 × 10-10 atm, Sn cations mainly substitute as Sn4+ at the B-site of perovskite NKN, whereas Sn2+ A-site substitution is favored under a low-pO2 atmosphere. Low-pO2 fired Sn-NKN ceramics exhibit higher relative permittivity, Curie temperature, and piezoelectric coefficient (d33). Sn2+ at A-site acts as a donor and reduces the p-type carrier concentrations that result from an electronic compensation of metal vacancies created through the high volatility of Na and K suboxides. The higher piezoelectricity and resistivity in low-pO2 fired Sn-NKN ceramics make this material suitable for base-metal cofired devices such as Ni-inner-electrode multilayer capacitors and actuators.

Kobayashi, Keisuke; Doshida, Yutaka; Mizuno, Youichi; Randall, Clive A.

2014-01-01

218

Investigation of high Curie temperature (1-x)BiSc1-yFeyO3-xPbTiO3 piezoelectric ceramics  

NASA Astrophysics Data System (ADS)

Ceramics around the morphotropic phase boundary (MPB) in the (1-x)BiSc1-yFeyO3-xPbTiO3 solid solution were fabricated. For y =0.5, ceramics were single phase, and piezoelectric coefficients (d33) and electromechanical coupling coefficients (kp) for MPB compositions were 300 pC/N and 0.49, respectively; a level of piezoelectric activity similar to that of hard, lead zirconate titanate compositions but with TC˜60 °C higher at ˜440 °C. For ceramics with y ?0.7, dielectric measurements in combination with diffraction contrast transmission electron microscopy revealed the existence of two ferroelectric phases for most PbTiO3 contents studied. The presence of two ferroelectric phases was associated with a decrease in piezoelectric activity and although raw materials costs for y =0.7 and 0.8 with respect to y =0 were significantly lower (less Sc2O3) and TC greater (˜500 °C), d33 (˜100 pC/N) and kp (0.18) were too low to be commercially useful for actuator applications.

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

2009-10-01

219

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

NASA Astrophysics Data System (ADS)

We report porous lead zirconate titanate ceramics fabricated by tert-butyl alcohol-based gel-casting process which show a very high thickness electromechanical coupling coefficient (0.77), high hydrostatic figure of merit (9594×10-15 m2/N), and low acoustic impedance (3.7 Mrayls). We show that the porosity effectively affects the performance of the samples in two ways: (1) a higher porosity simplifies the resonance behavior, leading to more efficient energy transduction; (2) its replacement of active ceramic phase leads to low relative permittivity, high hydrostatic figure of merit, and low acoustic impedance. It was confirmed the properties could be tailored by controlling the porosity.

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

2011-04-01

220

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

221

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

PubMed

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

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

2015-01-01

222

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

SciTech Connect

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

Chen Jianguo [Department of Materials Science and Engineering, College of Engineering, Peking University, Yiheyuan Road No.5, Beijing 100871 (China); School of Materials Science and Engineering, Shanghai University, Yanchang Road No. 149, Shanghai 200072 (China); Zhao Tianlong [Department of Materials Science and Engineering, College of Engineering, Peking University, Yiheyuan Road No.5, Beijing 100871 (China); School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100 (China); Cheng Jinrong [School of Materials Science and Engineering, Shanghai University, Yanchang Road No. 149, Shanghai 200072 (China); Dong Shuxiang [Department of Materials Science and Engineering, College of Engineering, Peking University, Yiheyuan Road No.5, Beijing 100871 (China)

2013-04-14

223

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

SciTech Connect

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.

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

224

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

SciTech Connect

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.

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

2009-04-15

225

Thickness dependence of hydrostatic piezoelectric properties of 1–3 piezoelectric composites  

Microsoft Academic Search

Thickness dependence of hydrostatic piezoelectric properties of 1–3 piezoelectric composites was studied. PZT rods with square cross section were used as piezoelectric active components. Epoxy resin was used as matrix. The volume fraction of piezoelectric ceramic was about 25%. The hydrostatic piezoelectric properties dh, gh and hydrostatic figure of merit dh gh are all dependent on the ratio of width

Li Denghua; Yao Xi

1999-01-01

226

Piezoelectric and ferroelectric properties of SrBi 2(Nb 1? ? Ta ? ) 2O 9 ceramics  

Microsoft Academic Search

SrBi2(Nb1??Ta?)2O9 (0???1.0) bismuth layered structured ferroelectric (BLSF) ceramics were prepared by the conventional solid-state reaction sintering method. XRD analysis indicated that a single phase of SrBi2(Nb1??Ta?)2O9 was formed for all compositions. The substitution of Ta for Nb decreases Curie temperature (Tc), maximum permittivity (?m), remnant polarization (Pr) and coercive field (Ec), whereas temperature coefficient of resonance frequency (TCF) increases with

Lin Sun; Chude Feng; Lidong Chen; Shiming Huang; Xiaowei Wen

2006-01-01

227

Influence of a silver epoxy dopant on the performance of broken piezoelectric ceramic transducer based on an analytical model  

NASA Astrophysics Data System (ADS)

Over the past decade, an unprecedented increase in the types of, the methods of using, and the demand for piezoelectric ceramic transducers (PCTs) has been observed in the market. These factors increase the probability of PCTs being subjected to breakage. Therefore, this study proposes a simple, low-cost procedure which uses available components to repair and reinstall five broken PCTs and then tests them as emitters and receivers in bulk and surface wave detection. An SM211 PCT with a 7.2 MHz frequency, a high damping and electromechanical coupling coefficient, and two silver electrodes were selected for the experiment. A Mason circuit was used for the procedure, the Laplace transform was used as a mathematical analysis method, and MATLAB was the technical computing language used to model the new transfer function for this type of PCT. This study proved that silver electrodes are a significant load on PCTs, particularly at high frequencies. Very good identity correlations between this mathematical and the experimental responses of the standard PCT were obtained. Later this mathematical model was used to prove the explanations provided by this research. The response of the standard PCT was compared with that of the samples of PCT that have been repaired (SPCTR). Through this comparison, many conclusions were obtained, and several recommendations were made, which can be taken advantage of by people who are interested in this field of research. Such recommendations include analyzing the response of SPCTR and explaining the types of ultrasonic tests in which SPCTR can be used.

Abdulhamed Mohammed, Arshed; Haris, Sallehuddin Mohamed; Zaki Nuawi, Mohd

2014-04-01

228

Assessment of stapes mobility by use of a newly developed piezoelectric ceramic device. A preliminary experiment in dogs.  

PubMed

A piezoelectric device was developed for assessment of stapes mobility during middle ear surgery. The device comprises a pair of ceramic bimorph elements: one for activation of the stapes and the other to pick up the vibration as an electric output, which varies in accordance with the stapes mobility, ie, the inverse of the cochlear input impedance (Zsc). The device is compact and easily manipulated even in the narrow surgical field of the ear. However, the measuring range is restricted to between 1 and 10 kHz. Measurement of Zsc was conducted with this device in 5 ears of 5 dogs. The mean magnitude of Zsc increased with frequency in the range from 1 to 10 kHz: 0.95 megohm at 1 kHz and 8.8 megohms at 10 kHz. After fixation of the stapes with dental cement, the magnitude increased to more than 10 megohms, except at 1 kHz. The results suggest that the device is useful in detecting decreases in stapes mobility in patients with chronic otitis media. PMID:10823476

Gyo, K; Sato, H; Yumoto, E; Yanagihara, N

2000-05-01

229

Measurement of losses in five piezoelectric ceramics between 2 and 50 MHz.  

PubMed

Approximate formulas including losses to predict the electrical impedance of a thin unloaded piezoelectric plate around antiresonant frequencies of the thickness modes have been derived. To do so, a total loss factor is defined that includes both mechanical and electrical losses. Complex electrical impedance measurements on a lead metaniobate and four PZT-type materials between 2 and 50 MHz have been performed. The total loss factors were deduced from both the peak real impedance and from the -6 dB bandwidth of the real impedance peak. Results for fundamental and harmonic thickness modes on thin plates are discussed and the five materials are compared. It is found that for these piezoceramics the total loss factor is well approximated by a linear function of frequency. Finally, a frequency-dependent loss factor is included in the KLM equivalent circuit and it is shown that the theoretical impedance curves obtained with this model are in good agreement with measurements. PMID:18263177

Lethiecq, M; Patat, F; Pourcelot, L; Tran-Huu-Hue, L P

1993-01-01

230

Enhanced piezoelectric properties of lead zirconate titanate sol-gel derived ceramics using single crystal PbZr0.52Ti0.48O3 cubes  

NASA Astrophysics Data System (ADS)

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

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

2010-09-01

231

Dielectric and Piezoelectric Properties of Low-Temperature-Sintering Pb(Mg1/2W1/2)O3-Pb(Ni1/3Nb2/3)O3-Pb(Zr,Ti)O3 Ceramics for Multilayer Piezoelectric Actuator  

NASA Astrophysics Data System (ADS)

In this study, in order to develop low-temperature-sintering ceramics for a multilayer piezoelectric actuator, Pb(Mg1/2W1/2)O3-Pb(Ni1/3Nb2/3)O3-Pb(Zr,Ti)O3 (PMW-PNN-PZT) ceramics were fabricated using Li2CO3 and CaCO3 as sintering aids and their dielectric and piezoelectric properties were investigated in relation to the amount of Bi substitution. Piezoelectric actuators require both a high piezoelectric constant (d33) and a high electromechanical coupling factor (kp). Accordingly, in this study, Bi was substituted at the Pb site of basic composition PMW-PNN-PZT ceramics for the enhancement of kp and d33. With increasing Bi substitution, density gradually increased. At the sintering temperature of 900°C, the electromechanical coupling factor (kp) and piezoelectric constant (d33) of PMW-PNN-PZT composition ceramics with 1.0 mol % Bi substitution as well as 0.2 wt % Li2CO3 and 0.25 wt % CaCO3 showed the optimal value of 0.618 and 473 pC/N, respectively, for multilayer piezoelectric actuator application.

Yoo, Juhyun; Yoo, Kyungjin; Lee, Hyunseok; Lee, Sangho; Chung, Kwanghyun; Lee, Hyeunggyu; Kang, Hyungwon

2005-09-01

232

Phase Transition and Electrical Properties of Ba0.7Ca0.3TiO3BiFeO3 Ceramics Cai-Xia Li,,  

E-print Network

Phase Transition and Electrical Properties of Ba0.7Ca0.3TiO3­BiFeO3 Ceramics Cai-Xia Li,,§ Bin Yang, University Park, Pennsylvania 16802 Lead-free piezoelectric ceramics of (1 À x)Ba0.70 Ca0.30TiO3­x BiFeO3 [(1 À x)BCT­xBF, x = 0­0.065] have been prepared and investigated. The ceramics with x 0.06 have

Cao, Wenwu

233

Mechanical bend fatigue reliability of lead-free PBGA assemblies  

Microsoft Academic Search

In recent years, proposed legislative action and the product differentiation opportunities presented by environmentally friendly products have combined to significantly increase the development of lead-free solder materials. A few lead-reduced products are already in production and several lead-free products will be released in the next two years. Among the various lead-free solders, the SnAgCu family of solders has emerged as

Krishna Jonnalagadda; M. Patel; Andrew Skipor

2002-01-01

234

Remarkably high-temperature stable piezoelectric properties of Bi(Mg0.5Ti0.5)O3 modified BiFeO3-BaTiO3 ceramics  

NASA Astrophysics Data System (ADS)

Dense (1-y)BiFe1-x(Mg0.5Ti0.5)xO3 - yBaTiO3 (BFMT-BT, y = 0.29, x = 0-0.12) ceramics with a pseudocubic perovskite crystal structure exhibit remarkably high-temperature stable piezoelectric properties. In particular, x = 0.03 BFMT-BT ceramics, with a Curie temperature, Tc, of ˜425 °C, show a stable piezoelectric coefficient, d33, of ˜155 pC/N up to a depolarization temperature, Td, of ˜400 °C. This Td is higher than Tc for Pb(Zr,Ti)O3, therefore suggesting BFMT-BT ceramics to be promising high-temperature Pb-free piezoelectric materials.

Zhou, Changrong; Feteira, Antonio; Shan, Xu; Yang, Huabin; Zhou, Qin; Cheng, Jun; Li, Weizhou; Wang, Hua

2012-07-01

235

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

NASA Astrophysics Data System (ADS)

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 (kt˜50%) 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.

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

2009-05-01

236

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

NASA Astrophysics Data System (ADS)

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 and NCBT were formed in situ topotaxially on the oriented BIT particles, and textured CBT and NCBT ceramics were eventually fabricated by the templated grain growth and densification. The Lotgering {001} orientation degree of the textured ceramics exceeded 90% for secondary-laminate sintered specimens. Textured CBT and NCBT ceramics poled in the perpendicular direction to the preferred <001> axis exhibited electromechanical coupling coefficient (k33) and piezoelectric coefficients (d33 and g33) three times higher than the values for nontextured ceramics with the same composition.

Takeuchi, Tsuguto; Tani, Toshihiko; Saito, Yasuyoshi

1999-09-01

237

Production of continuous piezoelectric ceramic fibers for smart materials and active control devices  

NASA Astrophysics Data System (ADS)

Advanced Cerametrics Inc. has conceived of and developed the Viscous-Suspension-Spinning Process (VSSP) to produce continuous fine filaments of nearly any powdered ceramic materials. VSSP lead zirconate titanate (PZT) fiber tows with 100 and 790 filaments have been spun in continuous lengths exceeding 1700 meters. Sintered PZT filaments typically are 10 - 25 microns in diameter and have moderate flexibility. Prior to carrier burnout and sintering, VSSP PZT fibers can be formed into 2D and 3D shapes using conventional textile and composite forming processes. While the extension of PZT is on the order of 20 microns per linear inch, a woven, wound or braided structure can contain very long lengths of PZT fiber and generate comparatively large output strokes from relatively small volumes. These structures are intended for applications such as bipolar actuators for fiber optic assembly and repair, vibration and noise damping for aircraft, rotorcraft, automobiles and home applications, vibration generators and ultrasonic transducers for medical and industrial imaging. Fiber and component cost savings over current technologies, such as the `dice-and-fill' method for transducer production, and the range of unique structures possible with continuous VSSP PZT fiber are discussed. Recent results have yielded 1-3 type composites (25 vol% PZT) with d33 equals 340 pC/N, K equals 470, and g33 equals 80 mV/N, kt equals 0.54, kp equals 0.19, dh equals 50.1pC/N and gh equals 13 mV/N.

French, Jonathan D.; Weitz, Gregory E.; Luke, John E.; Cass, Richard B.; Jadidian, Bahram; Bhargava, Parag; Safari, Ahmad

1997-05-01

238

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

PubMed

In spite of high piezoelectricity, only a few one-dimensional ferroelectric nano-materials with perovskite structure have been used for piezoelectric nanogenerator applications. In this paper, we report high output electrical signals, i.e. an open-circuit voltage of 3.2 V and a closed-circuit current of 67.5 nA (current density 9.3 nA cm(-2)) at 0.38% strain and 15.2% s(-1) strain rate, using randomly aligned lead-free KNbO(3) ferroelectric nanorods (~1 ?m length) with piezoelectric coefficient (d(33) ~ 55 pm V (-1)). A flexible piezoelectric nanogenerator is mainly composed of KNbO(3)-poly(dimethylsiloxane) (PDMS) composite sandwiched by Au/Cr-coated polymer substrates. We deposit a thin poly(methyl methacrylate) (PMMA) layer between the KNbO(3)-PDMS composite and the Au/Cr electrode to completely prevent dielectric breakdown during electrical poling and to significantly reduce leakage current during excessive straining. The flexible KNbO(3)-PDMS composite device shows a nearly frequency-independent dielectric constant (~3.2) and low dielectric loss (<0.006) for the frequency range of 10(2)-10(5) Hz. These results imply that short and randomly aligned ferroelectric nanorods can be used for a flexible high output nanogenerator as well as high-k capacitor applications by performing electrical poling and further optimizing the device structure. PMID:22922486

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

2012-09-21

239

The current status of lead-free solder alloys  

Microsoft Academic Search

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

D. Suraski; K. Seelig

2001-01-01

240

NASA-DoD Lead-Free Electronics Project  

NASA Technical Reports Server (NTRS)

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.

Kessel, Kurt

2007-01-01

241

Measuring droplet impact with piezoelectric film  

E-print Network

materials used in piezoelectric applications were barium titanate, rochelle salt and quartz (Klapholz, 1985). During World War H, researchers found that ceramics have high piezoelectric response. By 1960, researchers found that the polyvinylidene fluoride...

Basahi, Jalal M. Al-Badry M.

1993-01-01

242

Simple, high-resolution interferometer for the measurement of frequency-dependent complex piezoelectric responses in ferroelectric ceramics  

Microsoft Academic Search

In this paper, we report the development of a simple but precise piezoelectric spectrometer using a Michelson–Morley interferometer. The measurement system has been developed to study the frequency and temperature dependence of the complex piezoelectric and electrostriction coefficients of ferroelectric materials. The spectral data are collected by computer and has significantly wider frequency range and lower noise than other such

Jie-Fang Li; P. Moses; D. Viehland

1995-01-01

243

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

SciTech Connect

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

Lee, S. T. F.; Lam, K. H.; Lei, L.; Zhang, X. M.; Chan, H. L. W. [Department of Applied Physics and Materials Research Centre, The Hong Kong Polytechnic University, Kowloon (Hong Kong)

2011-02-15

244

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

NASA Astrophysics Data System (ADS)

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.

McNulty, Thomas Francis

245

Unique single-domain state in a polycrystalline ferroelectric ceramic  

NASA Astrophysics Data System (ADS)

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.

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

2014-03-01

246

A Drop-In Lead-Free Solder Replacement  

Microsoft Academic Search

Environmental and toxicity concerns related to the use of lead have initiated the search for acceptable, alternate joining materials for electronics assembly. This paper describes a novel lead-free solder designed as a \\

Ning-Cheng Lee; James A. Slattery; John R. Sovinsky; Paul T. Vianco

247

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

Microsoft Academic Search

(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

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

2009-01-01

248

Novel Testing Instrument for Lead-Free Solder Characterization  

Microsoft Academic Search

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

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

2011-01-01

249

Development of Sn-Zn-Cu lead free solder  

Microsoft Academic Search

Sn-Zn based lead free solder is one type of promising candidate to replace Sn-Pb eutectic solder due to its low cost and melt temperature which near to Sn-Pb eutectic solder. The Sn-Zn-Cu lead free solder was developed by alloying Sn with Zn and Cu in this paper. The effect of Zn and Cu content on the wettability of solder to

Yang Min; Liu Xiuzhong; Liu Xinghong; Dai Jiahui

2010-01-01

250

The creep of lead-free solders at elevated temperatures  

Microsoft Academic Search

Full implementation of the new generation of lead-free solders requires a detailed knowledge and understanding of their mechanical behavior. This paper reports an investigation of the creep behavior of three lead-free alloys: Sn-0.5 Cu, Sn-3.5 Ag, and Sn-3.8Ag-0.7Cu, at 75°C, and compares their response to that of Sn-37Pb at the same temperature. In terms of stress and time to rupture,

W. J. Plumbridge; C. R. Gagg; S. Peters

2001-01-01

251

Piezoelectric materials used in underwater acoustic transducers  

SciTech Connect

Piezoelectric materials have been used in underwater acoustic transducers for nearly a century. In this paper, we reviewed four different types of piezoelectric materials: piezoelectric ceramics, single crystals, composites, and polymers, which are widely used in underwater acoustic transducers nowadays. Piezoelectric ceramics are the most dominant material type and are used as a single-phase material or one of the end members in composites. Piezoelectric single crystals offer outstanding electromechanical response but are limited by their manufacturing cost. Piezoelectric polymers provide excellent acoustic impedance matching and transducer fabrication flexibility although their piezoelectric properties are not as good as ceramics and single crystals. Composites combined the merits of ceramics and polymers and are receiving increased attention. The typical structure and electromechanical properties of each type of materials are introduced and discussed with respect to underwater acoustic transducer applications. Their advantages and disadvantages are summarized. Some of the critical design considerations when developing underwater acoustic transducers with these materials are also touched upon.

Li, Huidong; Deng, Zhiqun; Carlson, Thomas J.

2012-07-07

252

NASA-DoD Lead-Free Electronics Project  

NASA Technical Reports Server (NTRS)

Original Equipment Manufacturers (OEMs). depots. and support contractors have to be prepared to deal with an electronics supply chain thaI increasingly provides parts with lead-free finishes. some labeled no differently and intenningled with their SnPb counterparts. Allowance oflead-free components presents one of the greatest risks to the reliability of military and aerospace electronics. The introduction of components with lead-free lenninations, tennination finishes, or circuit boards presents a host of concerns to customers. suppliers, and maintainers of aerospace and military electronic systems such as: 1. Electrical shorting due to tin whiskers; 2. Incompatibility oflead-free processes and parameters (including higher melting points of lead-free alloys) with other materials in the system; and 3. Unknown material properties and incompatibilities that could reduce solder joint re liability.

Kessel, Kurt

2011-01-01

253

Lead-free BaTiO3 nanowires-based flexible nanocomposite generator.  

PubMed

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

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

2014-08-01

254

Wettability analysis of tin-based, lead free solders  

SciTech Connect

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

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

1992-01-01

255

The creep of lead-free solders at elevated temperatures  

Microsoft Academic Search

Full implementation of the new generation of lead-free solders requires a detailed knowledge and understanding of their mechanical\\u000a behavior. This paper reports an investigation of the creep behavior of three lead-free alloys: Sn-0.5 Cu, Sn-3.5 Ag, and Sn-3.8Ag-0.7Cu,\\u000a at 75?C, and compares their response to that of Sn-37Pb at the same temperature. In terms of stress and time to rupture,

W. J. Plumbridge; C. R. Gagg; S. Peters

2001-01-01

256

Improved Piezoelectric Loudspeakers And Transducers  

NASA Technical Reports Server (NTRS)

Loudspeakers and related acoustic transducers of improved type feature both light weight and energy efficiency of piezoelectric transducers and mechanical coupling efficiency. Active component of transducer made from wafer of "rainbow" piezoelectric material, ceramic piezoelectric material chemically reduced on one face. Chemical treatment forms wafer into dishlike shallow section of sphere. Both faces then coated with electrically conductive surface layers serving as electrodes. Applications include high-fidelity loudspeakers, and underwater echo ranging devices.

Regan, Curtis Randall; Jalink, Antony; Hellbaum, Richard F.; Rohrbach, Wayne W.

1995-01-01

257

A Piezoelectric-Piezomagnetic Gyrator  

Microsoft Academic Search

A linear passive unilateral element, which has a high forward\\/backward transmission ratio at all frequencies, is realized by combining two resistances and an electromechanical gyrator according to Gamo's theory. The gyrator consists of three mechanically coupled ceramic elements, two of which may be piezomagnetic and the third piezoelectric, or two of which may be piezoelectric and the third piezomagnetic. In

M. Onoe; M. Sawabe

1962-01-01

258

DEVELOPMENT OF HIGH PERFORMANCE BS-PT BASED PIEZOELECTRIC TRANSDUCERS FOR HIGH-TEMPERATURE  

E-print Network

DEVELOPMENT OF HIGH PERFORMANCE BS-PT BASED PIEZOELECTRIC TRANSDUCERS FOR HIGH (BS-PT) based piezoelectric ceramic transducers for high-temperature SHM applications. By controlling environments. KEYWORDS : high-temperatue piezoelectric transducer, microfabrication, polyimide INTRODUCTION

Boyer, Edmond

259

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

Microsoft Academic Search

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.

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

2005-01-01

260

Nanoscale Mechanical Properties of Intermetallics in Lead-Free Systems  

Microsoft Academic Search

Bimetallic couples formed between commercially available lead free alloys and selected contact materials were subjected to diffusion annealing using thermal gradients. Following diffusion annealing and ageing, the contact interfaces were subjected to a detailed metallographic, Scanning Electron Microscope (SEM), Energy Dispersive X-Ray (EDX) analyses. In addition, electrical resistance was used for electrical characterization of the intermetallics formed at the contact

M. Braunovic; D. Gagnon; L. Rodrigue

2006-01-01

261

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

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).

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

262

Effect of Y and Mn Doping in Pb(T, Zr)O3 Piezoelectric Ceramics on the Resonant Frequency and Capacitance Changes and Aging by Thermal Shock Tests  

NASA Astrophysics Data System (ADS)

The effects of Y and Mn-doping in Pb(Zr, Ti)O3 (PZT) with respect to the resonant frequency changes and the aging phenomena caused by thermal treatment were studied in order to achieve a stable piezoelectric ceramic filter. Good thermal stability as well as a high mechanical quality factor QM were required for the piezoelectric ceramics to fabricate certain types of narrow band monolithic filters. The Cr-doped PZT showed a little aging phenomena in resonant frequency change after thermal shock tests, but QM was not high. The Cr and Mn-doped PZT had a large QM value, but a large amount of resonant frequency change and aging after thermal shock tests. It was observed that the PZT with the addition of Y and Mn has high QM and good temperature stability. These features were suitable for the use in filters and resonators.

Takahashi, Keiichi; Nishida, Masamitsu; Hase, Hiroyuki

1998-09-01

263

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

NASA Astrophysics Data System (ADS)

In this work, a large size lead-free piezoelectric single crystal, (K,Na,Li)(Nb,Ta,Sb)O3 (KNLNTS) with the dimensions of 8.5×8.5×13.5 mm3 was successfully grown by the top-seeded solution growth method. This KNLNTS single crystal with high compositional homogeneity is in the tetragonal phase at room temperature. The Curie temperature TC of the tetragonal-cubic phase transition temperature is 210 °C. The piezoelectric coefficients and electromechanical coupling factors of the [001]C oriented KNLNTS single crystal are d33=172.55 pC/N, d31=-71.90 pC/N, k31=0.327, k33=0.523, and kt=0.541. In addition, the crystal shows good thermal stability so that it can be used for making high temperature electromechanical devices.

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

2015-01-01

264

Evaluation of Lead Free Solder Joints in Electronic Assemblies  

Microsoft Academic Search

The feasibility of printed circuit board assembly with lead-free solder alloys was investigated. Studies were conducted with\\u000a two baseline eutectic binary alloys, SnBi and SnAg, and three new lead-free solder formulations: (1) 91.8Sn-4.8Bi-3.4Ag (wt%)\\u000a developed at Sandia Laboratories, (2) 77.2Sn-20In-2.8Ag developed at Indium Corp. of America, and (3) 96.2Sn-2.5Ag-0.8Cu-0.5Sb\\u000a provided by AIM Inc. The basic physical properties (melting temperature, wetting,

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

1994-01-01

265

Lead-Free Experiment in a Space Environment  

NASA Technical Reports Server (NTRS)

This Technical Memorandum addresses the Lead-Free Technology Experiment in Space Environment that flew as part of the seventh Materials International Space Station Experiment outside the International Space Station for approximately 18 months. Its intent was to provide data on the performance of lead-free electronics in an actual space environment. Its postflight condition is compared to the preflight condition as well as to the condition of an identical package operating in parallel in the laboratory. Some tin whisker growth was seen on a flight board but the whiskers were few and short. There were no solder joint failures, no tin pest formation, and no significant intermetallic compound formation or growth on either the flight or ground units.

Blanche, J. F.; Strickland, S. M.

2012-01-01

266

Ceramics  

NASA Astrophysics Data System (ADS)

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 50°C 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 1500°C, which shows dense and uniform microstructure as well as well-developed grain growth.

Yao, Lichun; Yang, Jian; Qiu, Tai

2014-09-01

267

UHV piezoelectric translator  

SciTech Connect

A UHV compatible piezoelectric translator has been developed to correct for angular misalignments in the crysals of a UHV x-ray monochromator. The unit is small, bakeable to 150/sup 0/C, and uses only ceramic materials for insulation. We report on the construction details, vacuum compatibility, mechanical properties, and uses of the device.

Oversluizen, T.; Watson, G.

1985-01-01

268

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

Microsoft Academic Search

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

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

1994-01-01

269

Active Piezoelectric Diaphragms  

NASA Technical Reports Server (NTRS)

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.

Bryant, Robert G.; Effinger, Robert T., IV; Aranda, Isaiah, Jr.; Copeland, Ben M.; Covington, Ed W., III

2002-01-01

270

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

NASA Astrophysics Data System (ADS)

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

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

2015-03-01

271

Microstructural characteristics and electrical properties of xPb(Mg 1\\/3Ta 2\\/3)O 3–(0.1 ? x)Pb(Mn 1\\/3Sb 2\\/3)O 3–0.9Pb(Zr 0.52Ti 0.48)O 3 high power piezoelectric ceramics  

Microsoft Academic Search

The quaternary piezoelectric ceramics of Pb(Mg1\\/3Ta2\\/3)O3–Pb(Mn1\\/3Sb2\\/3)O3–Pb(Zr0.52Ti0.48)O3 (PMgT–PMnS–PZT) were synthesized with a conventional method. The phase, microstructure, ferroelectric, dielectric and piezoelectric properties were studied in terms of PMgT content. The results indicate that all ceramics have a pure perovskite phase of tetragonal symmetry while the c\\/a ratio increases with PMgT content. The PMgT substitution also promotes the densification of the ceramics

Qian Li; Ying Yang; Dandan Wan; Yu Cheng; Meng Zha

2009-01-01

272

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

E-print Network

The review of current technologies for measurement of gas velocity in stack flow applications is undertaken and it is shown that the ultrasonic time-of-flight method is the most suitable and offers a number of advantages over alternatives. Weakness...

Krsmanovic, Dalibor

2011-11-08

273

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

NASA Astrophysics Data System (ADS)

Using electron diffraction, trends in the local structural behaviour of the KxNa1-xNbO3 (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]p* (p for parent sub-structure) across the entire phase diagram, indicative of ferroelectric disorder along the [0 1 0]p direction co-existing with long range ferroelectric order along the orthogonal [1 0 0]p and [0 0 1]p directions. An additional characteristic pattern of diffuse scattering is also observed, involving rods of diffuse intensity running along the [1 0 0]p* and [0 0 1]p* directions of the perovskite sub-structure and indicative of octahedral tilt disorder about the [1 0 0]p and [0 0 1]p axes co-existing with long range ordered octahedral tilting around the [0 1 0]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.

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

2012-11-01

274

Theoretical and experimental research on the influence of multiple piezoelectric effects on physical parameters of piezoelectric actuator  

NASA Astrophysics Data System (ADS)

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.

Shi, Liping; Zhou, Haimin; Huang, Jie; Tan, Jiliang

2015-04-01

275

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

NASA Astrophysics Data System (ADS)

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

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

2014-08-01

276

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

Microsoft Academic Search

[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

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

2007-01-01

277

Theoretical and experimental investigation of traveling wave propagation on a several- millimeter-long cylindrical pipe driven by piezoelectric ceramic tubes.  

PubMed

A novel method is presented for investigation of the traveling wave propagation generated on a thin film pipe with a short length of several millimeters. As a bridge to connect two piezoelectric ceramic (lead zirconate titanate, PZT) tubes, a thin-film metallic glass (TFMG) pipe is fabricated by a new technique of rotating magnetron sputtering. The vibrator combines the vibration of the axial mode of the PZT tube and the radial mode of the TFMG pipe. Theoretical analyses of the TFMG pipe and PZT tube, with a comparison of the finite element modeling, clarify the vibration characteristics so that the proper geometrical sizes, suitable boundary conditions, and driving voltage signals are designed. In the experiment, the designed vibrator was fabricated and the vibration characteristics were measured by a laser Doppler vibrometer system. The pure traveling wave propagation obtained theoretically and experimentally demonstrates the validity of this work. This study shows a new way to achieve a pure traveling wave on a short cylindrical pipe driven by PZT tubes. PMID:20639154

Sun, Dongming; Wang, Sheng; Hata, Seiichi; Sakurai, Junpei; Shimokohbe, Akira

2010-07-01

278

Thermodynamics and phase diagrams of lead-free solder materials  

Microsoft Academic Search

Many of the existing and most promising lead-free solders for electronics contain tin or tin and indium as a low melting base\\u000a alloy with small additions of silver and\\/or copper. Layers of nickel or palladium are frequently used contact materials. This\\u000a makes the two quaternary systems Ag–Cu–Ni–Sn and Ag–In–Pd–Sn of considerable importance for the understanding of the processes\\u000a that occur

H. Ipser; H. Flandorfer; Ch. Luef; C. Schmetterer; U. Saeed

2007-01-01

279

Thermodynamics and phase diagrams of lead-free solder materials  

Microsoft Academic Search

Many of the existing and most promising lead-free solders for electronics contain tin or tin and indium as a low melting base\\u000a alloy with small additions of silver and\\/or copper. Layers of nickel or palladium are frequently used contact materials. This\\u000a makes the two quaternary systems Ag-Cu-Ni-Sn and Ag-In-Pd-Sn of considerable importance for the understanding of the processes\\u000a that occur

H. Ipser; H. Flandorfer; Ch. Luef; C. Schmetterer; U. Saeed

280

Aging in the relaxor and ferroelectric state of Fe-doped (1-x)(Bi{sub 1/2}Na{sub 1/2})TiO{sub 3}-xBaTiO{sub 3} piezoelectric ceramics  

SciTech Connect

Aging of piezoelectric properties was investigated in lead-free (1???x)(Bi{sub 1/2}Na{sub 1/2})TiO{sub 3}-xBaTiO{sub 3} doped with 1at.?% Fe. The relaxor character of the un-poled material prevents macroscopic aging effects, while in the field-induced ferroelectric phase aging phenomena are similar to those found in lead zirconate titanate or barium titanate. Most prominent aging effects are the development of an internal bias field and the decrease of switchable polarization. These effects are temperature activated, and can be explained in the framework of defect complex reorientation. This picture is further supported by electron paramagnetic resonance spectra indicating the existence of (Fe{sub Ti}{sup ?}?V{sub O}{sup ••}){sup •} defect complexes in the Fe-doped material.

Sapper, Eva; Dittmer, Robert; Rödel, Jürgen [Materials Science Department, Technische Universität Darmstadt, 64287 Darmstadt (Germany); Damjanovic, Dragan [Ceramics Laboratory, École Polytechnique Fédérale de Lausanne, Lausanne 1015 (Switzerland); Erdem, Emre [Institute of Physical Chemistry I, Universität Freiburg, 79104 Freiburg (Germany); Keeble, David J. [Division of Electronic Engineering and Physics, University of Dundee, Dundee DD1 4HN (United Kingdom); Jo, Wook [School of Materials Science and Engineering, Ulsan National Institute of Science and Technology, Ulsan 689-798 (Korea, Republic of); Granzow, Torsten [Centre de Recherche Public—Gabriel Lippmann, L-4422 Belvaux (Luxembourg)

2014-09-14

281

Aging in the relaxor and ferroelectric state of Fe-doped (1-x)(Bi1/2Na1/2)TiO3-xBaTiO3 piezoelectric ceramics  

NASA Astrophysics Data System (ADS)

Aging of piezoelectric properties was investigated in lead-free (1 - x)(Bi1/2Na1/2)TiO3-xBaTiO3 doped with 1at. % Fe. The relaxor character of the un-poled material prevents macroscopic aging effects, while in the field-induced ferroelectric phase aging phenomena are similar to those found in lead zirconate titanate or barium titanate. Most prominent aging effects are the development of an internal bias field and the decrease of switchable polarization. These effects are temperature activated, and can be explained in the framework of defect complex reorientation. This picture is further supported by electron paramagnetic resonance spectra indicating the existence of (FeTi'-VO••)• defect complexes in the Fe-doped material.

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

2014-09-01

282

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

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.

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

283

Investigation of multi-component lead-free solders  

NASA Astrophysics Data System (ADS)

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

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

1994-08-01

284

Rare earths in lead-free oxyfluoride germanate glasses  

NASA Astrophysics Data System (ADS)

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

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

2015-01-01

285

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

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.

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

286

Ceramics  

NASA Astrophysics Data System (ADS)

The microstructure and thermoelectric properties of Yb-doped Ca0.9- x Yb x La0.1 MnO3 (0 ? x ? 0.05) ceramics prepared by using the Pechini method derived powders have been investigated. X-ray diffraction analysis has shown that all samples exhibit single phase with orthorhombic perovskite structure. All ceramic samples possess high relative densities, ranging from 97.04% to 98.65%. The Seebeck coefficient is negative, indicating n-type conduction in all samples. The substitution of Yb for Ca leads to a marked decrease in the electrical resistivity, along with a moderate decrease in the absolute value of the Seebeck coefficient. The highest power factor is obtained for the sample with x = 0.05. The electrical conduction in these compounds is due to electrons hopping between Mn3+ and Mn4+, which is enhanced by increasing Yb content.

Zhang, Bo; Chang, Aimin; Zhao, Qing; Ye, Haitao; Wu, Yiquan

2014-11-01

287

ceramic  

NASA Astrophysics Data System (ADS)

We report that magnetism, especially ferromagnetism, can be induced in a nonmagnetic ferroelectric oxide such as barium titanate (BaTiO3) with choosing of suitable dopants. High-density polycrystalline sample of BaTi0.9Hf0.05Co0.05O3 was prepared using solid-state sintering route, and the effect of Co and Hf substitution on structural, magnetic and ferroelectric properties of BaTiO3 was studied. The magnetic order obtained in the above sample is of intrinsic in nature. Ferromagnetic behavior shown in the BaTi0.9Hf0.05Co0.05O3 ceramic may be attributed to the effective exchange interactions between oxygen vacancies and Co ions. BaTi0.9Hf0.05Co0.05O3 ceramic has also shown ferroelectric (lossy type) behavior.

Das, S. K.; Mishra, R. N.; Roul, B. K.

2014-09-01

288

Ceramics  

NASA Astrophysics Data System (ADS)

Perovskite Ba0.999Pr0.001TiO3 ceramics has been prepared through a solid-state reaction method. Dielectric properties of the doped BaTiO3 (barium titanate) ceramics as a function of temperature at frequencies of 1 kHz, 10 kHz, 100 kHz, and 1 MHz are studied and reported here. Analyzing the empirical parameters, it has been shown that the Pr3+ addition up-shifted the temperature of the maximal dielectric constant to 180 (K) at 1 kHz. The value of the dielectric constant at higher frequencies dropped markedly. Such a marked drop in the value of the dielectric constant at higher frequencies can be explained in terms of interfacial polarization. The high dielectric constant at lower frequencies is due to the build-up of charges at the grain-grain boundary interface which is responsible for the large polarization. The ceramic was subjected to Rietveld refinement for quantitative analysis of the microstructure of the material.

Panigrahi, M. R.

2014-09-01

289

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

SciTech Connect

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.

Yan, Yongke [Bio-Inspired Materials and Devices Laboraory (BMDL); Cho, Kyung-Hoon [Bio-Inspired Materials and Devices Laboraory (BMDL); Maurya, Deepam [ORNL; Kumar, Amit [ORNL; Kalinin, Sergei V [ORNL; Khachaturyan, Armen [State University of New Jersey, The; Priya, Shashank [ORNL

2013-01-01

290

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

NASA Astrophysics Data System (ADS)

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

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

2015-02-01

291

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

NASA Astrophysics Data System (ADS)

In view of the need for a lead-free, drop-in replacement for the widely used 40Pb-60Sn near-eutectic solder (m.p. ~183°C), new Sn-Zn-ln based alloys with substantially the same melting point have been developed. It is shown that the alloying additions of In to the Sn-Zn binary system result in a suppression of the melting point to 175-188°C, and at the same time significantly improve the wetting characteristics. While a relatively active flux may be required for good solderability in air atmosphere, the recent manufacturing trend of using inert atmospheres is likely to allow acceptable manufacturability using less active fluxes in the future.

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

1994-07-01

292

Can Whiskers Grow on Bulk Lead-Free Solder?  

NASA Astrophysics Data System (ADS)

Many possible mechanisms for whisker growth exist, each possible in various scenarios investigated in the literature. This contribution addresses the importance of residual mechanical stress in a solder alloy for providing some of the energy necessary to drive possible whisker growth. We investigate the indentations made on bulk lead-free solder (Sn3.5Ag) to introduce various levels of residual energy associated with localized residual stresses. We confirm that localized residual stresses, in the absence of a thin-film geometry, significant oxide thickness, and interdiffusional stresses from intermetallic Cu-Sn compounds, do not result in the formation of whiskers in bulk Sn3.5Ag. Thus, the combination of stresses associated with thin films (either thermal misfit, plating, or chemical) and the oxidation of Sn at the surface is likely required for continuous whisker growth.

Nychka, John A.; Li, Yan; Yang, Fuqian; Chen, Rong

2008-01-01

293

Development of fluxes for lead-free solders containing zinc  

SciTech Connect

New lead-free solders based on the Sn-Zn eutectic (92 wt. pct Sn - 8 wt. pct Zn) are promising candidates to replace near-eutectic tin-lead solders because these solders are less expensive than alternatives such as Sn-Ag eutectic base solders and the melting point of the tin-zinc eutectic (198 C) is much closer to melting point of commonly used tin-lead eutectic (183 C) than the melting point of the Sn-Ag eutectic (221 C). Solders based on the Sn-Zn eutectic have been shown to have excellent mechanical properties. However, the Zn-bearing solders oxidize easily during soldering and for this and perhaps other reasons the contact angle on copper for Sn-Zn solders is rather high when utilized with fluxes used for Sn-Pb solders. Tin chloride containing fluxes give satisfactory wetting of Sn-Zn eutectic solders on Cu but tin chloride is corrosive and, therefore, unacceptable as a flux for electronic applications. Development of a non-corrosive flux that gives satisfactory wetting of copper surfaces by tin-zinc eutectic solders is thus needed. At the present time tin or tin-lead solders are used for pre-tinning. This procedure adds to the production cost. Also Sn-Pb coatings are unacceptable for a lead-free soldering system. As this paper demonstrates, a tin containing organic compound that decomposes at soldering temperatures to produce metallic tin on surfaces to be soldered can be added to the flux to improve wetting of Sn-Zn eutectic solder on Cu. It may also be used for general pretinning purposes done before soldering.

Vaynman, S.; Fine, M.E.

1999-11-19

294

Improvement of Temperature Dependence of Piezoelectric Elements  

NASA Astrophysics Data System (ADS)

The relationships between the equivalent circuit constants of a piezoelectric element and the piezoelectric d33- and g33-constants were first clarified. The temperature dependence of the composed equivalent circuit constants was then decreased by connecting the piezoelectric element to a temperature-compensating capacitor, either in series or in parallel. Furthermore, new sandwich-like piezoelectric elements consisting of stacked piezoelectric ceramic and dielectric ceramic layers were constructed to decrease the dependence on temperature. The piezoelectric d33-constant of Pb(Zr, Ti)O3 changed by about 15% over the temperature range of 0 to 160° C. The new sandwich-like element, however, exhibited a change of less than 3% over the same temperature range.

Nagata, Kunihiro; Harashima, Eiki

1994-09-01

295

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

PubMed

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

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

2015-01-01

296

Enhanced depolarization temperature in 0.90NBT-0.05KBT-0.05BT ceramics induced by BT nanowires  

NASA Astrophysics Data System (ADS)

The depolarization temperature (Td) of piezoelectric materials is an important figure of merit for their application at elevated temperatures. This study focuses on the effect of BaTiO3 (BT) nanowires on Td and piezoelectric properties of morphotropic-phase-boundary 0.90NBT-0.05KBT-0.05BT ceramics. The results reveal that BaTiO3 nanowires can pin the domain wall, leading to the increase of coercive field (Ec) from 21.06 kV/cm to 34.99 kV/cm. The Td value of 0.90NBT-0.05KBT-0.05BT ceramics can be enhanced approximately 20 °C when using BT nanowires instead of BT solution as the raw material. Meanwhile, at the same polarization conditions, the piezoelectric constant of the ceramic added BT nanowires (172 pC/N) is decreased but still remains a larger value compared with those of other lead-free ceramics. The results imply that the addition of BT nanowires into NBT-KBT is a very effective route to improve Td.

Cao, W. P.; Li, W. L.; Feng, Y.; Xu, D.; Wang, W.; Hou, Y. F.; Zhang, T. D.; Fei, W. D.

2015-03-01

297

Diffuse transition and piezoelectric properties of Pb[(Zr 1? x Ti x ) 0.74(Mg 1\\/3Nb 2\\/3) 0.20(Zn 1\\/3Nb 2\\/3) 0.06]O 3 Ceramics  

Microsoft Academic Search

In this work, the piezoelectric ceramic system of Pb[(Zr1?xTix)0.74(Mg1\\/3Nb2\\/3)0.20(Zn1\\/3Nb2\\/3)0.06]O3, 0.47?x?0.57, with composition close to the morphotropic phase boundary, was studied. From the results of X-ray diffraction and piezoelectric measurement, ceramics near x=0.51 were found at the morphotropic phase boundary (MPB) between the tetragonal and pseudocubic perovskite. The planar coupling factor (kp=0.72) is high at compositions near the MPB, but the

Chun Huy Wang

2004-01-01

298

Study on Pb(Zr,Ti)O 3–Pb(Zn 1\\/3Nb 2\\/3)O 3–Pb(Sn 1\\/3Nb 2\\/3)O 3–Pb(Mn 1\\/3Sb 2\\/3)O 3 quinary system piezoelectric ceramics  

Microsoft Academic Search

In this paper, Pb(Zr,Ti)O3–Pb(Zn1\\/3Nb2\\/3)O3–Pb(Sn1\\/3Nb2\\/3)O3–Pb(Mn1\\/3Sb2\\/3)O3 (named briefly PZT–PZN–PSN–PMS) quinary system piezoelectric ceramics with various Zr\\/Ti ratio were prepared by traditional method. The properties of this quinary system piezoelectric ceramics were studied and the effect of Sr2+, Ba2+ doping on dielectric constant ?r3T and Curie temperature Tc were investigated. What's more, the dielectric loss tan? and dielectric constant ?r3T under the strong

Lin Sun; Chude Feng; Qingchi Sun; Hua Zhou

2005-01-01

299

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

PubMed

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

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

2014-03-01

300

High-Temperature Piezoelectrics with Large Piezoelectric Coefficients  

NASA Astrophysics Data System (ADS)

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.

Shinekumar, K.; Dutta, Soma

2015-02-01

301

Experiments to Demonstrate Piezoelectric and Pyroelectric Effects  

ERIC Educational Resources Information Center

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…

Erhart, Jirí

2013-01-01

302

Piezoelectric Polymers  

NASA Technical Reports Server (NTRS)

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.

Harrison, J. S.; Ounaies, Z.; Bushnell, Dennis M. (Technical Monitor)

2001-01-01

303

Local and Global Properties of a Lead-Free Solder  

NASA Astrophysics Data System (ADS)

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.

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

2013-07-01

304

Piezoelectric properties and temperature stability of Mn-doped Pb(Mg1/3Nb2/3)-PbZrO3-PbTiO3 textured ceramics  

NASA Astrophysics Data System (ADS)

In this letter, we report the electromechanical properties of textured 0.4Pb(Mg1/3Nb2/3)O3-0.25PbZrO3-0.35PbTiO3 (PMN-PZT) composition which has relatively high rhombohedral to tetragonal (R-T) transition temperature (TR-T of 160 °C) and Curie temperature (TC of 234 °C) and explore the effect of Mn-doping on this composition. It was found that MnO2-doped textured PMN-PZT ceramics with 5 vol. % BaTiO3 template (T-5BT) exhibited inferior temperature stability. The coupling factor (k31) of T-5BT ceramic started to degrade from 75 °C while the random counterpart showed a very stable tendency up to 180 °C. This degradation was associated with the "interface region" formed in the vicinity of BT template. MnO2 doped PMN-PZT ceramics textured with 3 vol. % BT and subsequently poled at 140 °C (T-3BT140) exhibited very stable and high k31 (>0.53) in a wide temperature range from room temperature to 130 °C through reduction in the interface region volume. Further, the T-3BT140 ceramic exhibited excellent hard and soft combinatory piezoelectric properties of d33 = 720 pC/N, k31 = 0.53, Qm = 403, tan ? = 0.3% which are very promising for high power and magnetoelectric applications.

Yan, Yongke; Cho, Kyung-Hoon; Priya, Shashank

2012-03-01

305

Piezoelectric valve  

DOEpatents

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.

Petrenko, Serhiy Fedorovich

2013-01-15

306

Mechanical Properties and Microstructure Investigation of Lead Free Solder  

NASA Technical Reports Server (NTRS)

While the electronics industry appears to be focusing on Sn-Ag-Cu as the alloy of choice for lead free electronics assembly, ,the exact composition varies by geographic region, supplier and user. Add to that dissolved copper and silver from the printed circuit board traces and surface finish, and there can be significant variation in the final solder joint composition. A systematic study of the mechanical and microstructural properties of Sn-Ag-Cu alloys with Ag varying from 2wt% to 4wt% and Cu varying from 0.5wt% to lSwt%, was undertaken in this research study. Different sample preparation techniques (water quenched, oil quenched and water quenched followed by reflow) were explored and the resulting microstructure compared to that of a typical reflowed lead free chip scale package (CSP) solder joint. Tensile properties (modulus, 0.2% yield strength and the ultimate tensile strength) and creep behavior of selected alloy compositions (Sn-4Ag-1 X u , Sn-4Ag-OSCu, Sn- 2Ag-1 X u , Sn-2Ag-OSCu, Sn-3.5Ag-O.SCu) were determined for three conditions: as- cast; aged for 100 hours at 125OC; and aged for 250 hours at 125OC. There was no significant difference in Young's Modulus as a function of alloy composition. After an initial decrease in modulus after 100 hours at 125"C, there was an insignificant change with further aging. The distribution of 0.2% strain yield stress and ultimate tensile strength as a function of alloy composition was more significant and decreased with aging time and temperature. The microstructures of these alloys were examined using light and scanning electron microscopy (LM and SEM) respectively and SEM based energy dispersive x-ray spectroscopy (EDS). Fracture surface and cross-section analysis were performed on the specimens after creep testing. The creep testing results and the effect of high temperature aging on mechanical properties is presented for the oil quenched samples. In general the microstructure of oil quenched specimen exhibited a eutectic region of Sn with moderately dispersed Ag3Sn intermetallic, surrounded by a dendritic Sn-rich phase. The SEM images of the fracture surface indicated the presence of a tough shear surface at the initial cavity break area and a break line in the middle of specimen along the failure direction. A hyperbolic-sine creep model was adopted and used to fit the creep experiment data. The effect on the mechanical properties by adding the quaternary element bismuth to the Sn-3.5Ag-0.8Cu alloy was measured and compared with the mechanical properties of the ternary alloys. The results of this research study provide necessary data for the modeling of solder joint reliability for a range of Sn-Ag-Cu compositions and a baseline for evaluating the effects of subsequent quaternary additions.

Wang, Qing; Gail, William F.; Johnson, R. Wayne; Strickland, Mark; Blanche, Jim

2005-01-01

307

Investigation of electromigration behavior in lead-free flip chip solder bumps  

NASA Astrophysics Data System (ADS)

Packaging technology has also evolved over time in an effort to keep pace with the demanding requirements. Wirebond and flip chip packaging technologies have become extremely versatile and ubiquitous in catering to myriad applications due to their inherent potential. This research is restricted strictly to flip chip technology. This technology incorporates a process in which the bare chip is turned upside down, i.e., active face down, and is bonded through the I/O to the substrate, hence called flip chip. A solder interconnect that provides electrical connection between the chip and substrate is bumped on a processed silicon wafer prior to dicing for die-attach. The assembly is then reflow-soldered followed by the underfill process to provide the required encapsulation. The demand for smaller and lighter products has increased the number of I/Os without increasing the package sizes, thereby drastically reducing the size of the flip chip solder bumps and their pitch. Reliability assessment and verification of these devices has gained tremendous importance due to their shrinking size. To add to the complexity, changing material sets that are results of recently enacted lead-free solder legislations have raised some compatibility issues that are already being researched. In addition to materials and process related flip chip challenges such as solder-flux compatibility, Coefficient of Thermal Expansion (CTE) mismatch, underfill-flux compatibility and thermal management, flip chip packages are vulnerable to a comparatively newer challenge, namely electromigration observed in solder bumps. It is interesting to note that electromigration has come to the forefront of challenges only recently. It has been exacerbated by the reduction in bump cross-section due to the seemingly continuous shrinking in package size over time. The focus of this research was to understand the overall electromigration behavior in lead-free (SnAg) flip chip solder bumps. The objectives of the research were to comprehend the physics of failure mechanism in electromigration for lead-free solder bumps assembled in a flip chip ceramic package having thick copper under bump metallization and to estimate the unknown critical material parameters from Black's equation that describe failure due to electromigration. In addition, the intent was to verify the 'use condition reliability' by extrapolation from experimental conditions. The methodology adopted for this research was comprised of accelerated electromigration tests on SnAg flip chip solder bumps assembled on ceramic substrate with a thick copper under bump metallization. The experimental approach was comprised of elaborate measurement of the temperature of each sample by separate metallization resistance exhibiting positive resistance characteristics to overcome the variation in Joule heating. After conducting the constant current experiments and analyzing the failed samples, it was found that the primary electromigration failure mode observed was the dissolution of the thick copper under bump metallization in the solder, leading to a change in resistance. The lifetime data obtained from different experiments was solved simultaneously using a multiple regression approach to yield the unknown Black's equation parameters of current density exponent and activation energy. In addition to the implementation of a systematic failure analysis and data analysis procedure, it was also deduced that thermomigration due to the temperature gradient across the chip does impact the overall electromigration behavior. This research and the obtained results were significant in bridging the gap for an overall understanding of this critical failure mode observed in flip chip solder bumps. The measurement of each individual sample temperature instead of an average temperature enabled an accurate analysis for predicting the 'use condition reliability' of a comparable product. The obtained results and the conclusions can be used as potential inputs in future designs and newer generations of flip chip devices that might undergo

Kalkundri, Kaustubh Jayant

308

Piezoelectric transformer structural modeling--a review.  

PubMed

A review on piezoelectric transformer structural modeling is presented. The operating principle and the basic behavior of piezoelectric transformers as governed by the linear theory of piezoelectricity are shown by a simple, theoretical analysis on a Rosen transformer based on extensional modes of a nonhomogeneous ceramic rod. Various transformers are classified according to their structural shapes, operating modes, and voltage transforming capability. Theoretical and numerical modeling results from the theory of piezoelectricity are reviewed. More advances modeling on thermal and nonlinear effects also are discussed. The article contains 167 references. PMID:17571814

Yang, Jiashi

2007-06-01

309

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

NASA Astrophysics Data System (ADS)

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.

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

2010-10-01

310

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

NASA Astrophysics Data System (ADS)

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

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

2014-12-01

311

Reliability model for assessment of lifetime of lead-free solder joints  

Microsoft Academic Search

Legal limitation on dangerous substance resulted into ban on use of lead soldering alloy in electrical industry. The era of lead-free alloys based on tin is coming. Lead-free solders are “young” and their characteristics haven't been surveyed sufficiently yet. Many research teams try to answer an easy question: “How reliable the lead-free solders are?” The given study deals with possible

O. Svecova; P. Kosina; J. Sandera; I. Szendiuch

2011-01-01

312

Structure and electrical properties of Na1/2Bi1/2TiO3-xK1/2Bi1/2TiO3 lead-free ferroelectric single crystals  

NASA Astrophysics Data System (ADS)

Dielectric, ferroelectric and piezoelectric properties of lead-free Na1/2Bi1/2TiO3-xK1/2Bi1/2TiO3 (NBT-xKBT) ferroelectric single crystals were characterized systematically. With increasing KBT concentration, the remanent polarization and coercive electric field decrease, while the piezoelectric constant and the electromechanical coupling coefficient increase. The evolution of average and local structures as a function of temperature and composition was investigated using in-situ X-ray diffraction and Raman spectroscopy. The structure/property relationship of NBT-xKBT single crystals was discussed in detail.

Zhang, Haiwu; Chen, Chao; Zhao, Xiangyong; Deng, Hao; Ren, Bo; Li, Xiaobing; Luo, Haosu; Li, Shundao

2015-01-01

313

Piezoelectric spectroscopy  

Microsoft Academic Search

In this paper, we report the development of a piezoelectric spectrometer using a Michelson-Morely interferometer. The measurement system has been developed to study the frequency and temperature dependence of the complex piezoelectric and electrostriction coefficients of ferroelectric materials. The system is controlled by computer and has very significantly wider frequency range and lower noise than previously developed systems. Results are

Jie Fang Li; Paul Moses; Dwight Viehland

1994-01-01

314

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 itâ??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.

315

Piezoelectric films  

NASA Astrophysics Data System (ADS)

The physical properties of piezoelectric materials for use in microelectronics are described with particular emphasis on SAW propagation. Piezoelectric-film (PF) fabrication processes are discussed, with consideration given to sputtering and chemical vapor deposition. The properties (acoustic, optical, and mechanical) of PFs are examined along with their applications (e.g., in BAW and SAW devices).

Shermergor, Timofei Dmitrievich; Strel'Tsova, Natalia Nikolaevna

316

Lead-Free vs Tin-Lead Reliability of Advanced Electronic Assemblies  

NASA Technical Reports Server (NTRS)

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.

Ghaffarian, Reza

2005-01-01

317

Journal of SMT October 2000 The move toward lead-free electronics has become a rapidly  

E-print Network

for lead-free soldering. BACKGROUND The movement toward lead-free electronics has emerged into concrete and fluorescent tubes, and lead as an alloying agent in steel (copper ( amounts of other elements (Ag, Au, Ni, Ge, In). For reflow soldering they identified one low temperature

Bennett, Gisele

318

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

NASA Astrophysics Data System (ADS)

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.

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

2015-02-01

319

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)

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.

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

2014-07-01

320

Improving the dielectric and piezoelectric properties of screen-printed Low temperature PZT/polymer composite  

E-print Network

PZT, Barium titanate BeTiO3) are brittle but offer high d33 (350-560 pC/N) and high dielectric materials, ceramics, polymers and composites. Ceramic piezoelectric materials (e.g. lead zirconate titanate

321

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

NASA Astrophysics Data System (ADS)

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

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

2015-04-01

322

Dielectric, piezoelectric and damping properties of novel 2-2 piezoelectric composites  

NASA Astrophysics Data System (ADS)

Here, a strip-shaped 2-2 cement/polymer-based piezoelectric composite was designed and fabricated. The dielectric, piezoelectric and electromechanical coupling properties of the composite were investigated as well as the coupling effects between the thickness and lateral modes of the piezoelectric composites. The dielectric and piezoelectric properties of the composites can be greatly influenced by variations of the piezoelectric ceramic volume fraction and the structural dimensions of the composites. Excellent properties have been achieved for ultrasonic transducer applications in civil engineering monitoring fields, such as large piezoelectric voltage constants, high thickness electromechanical coupling coefficients and low acoustic impedance. The damping property of the composites was especially studied. The maximum damping loss factor of the composites is between 0.28–0.32, and the glass transition temperature is between 55°–66 °C.

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

2015-02-01

323

Large piezoelectricity in Pb-free 0.96(K0.5Na0.5)0.95Li0.05Nb0.93Sb0.07O3-0.04BaZrO3 ceramic: A perspective from microstructure  

NASA Astrophysics Data System (ADS)

We employ transmission electron microscopy to explore the reason for large piezoelectricity (d33?400pC/N) in a Pb-free 0.96(K0.5Na0.5)0.95Li0.05Nb0.93Sb0.07O3 -0.04BaZrO3 ceramic from microstructure. The result shows that the high piezoelectricity corresponds to a miniaturized nanodomain configuration in a domain hierarchy. The nanodomains disappear on heating accompanied by a reduction in d33 value. Further convergent beam electron diffraction study reveals a coexistence of tetragonal and orthorhombic phase, which indicates that large piezoelectricity of KNLNS0.07-BZ may stem from easy polarization rotation due to low polarization anisotropy on the tetragonal-orthorhombic phase boundary.

Gao, Jinghui; Hao, Yanshuang; Ren, Shuai; Kimoto, Takayoshi; Fang, Minxia; Li, Huiying; Wang, Yu; Zhong, Lisheng; Li, Shengtao; Ren, Xiaobing

2015-02-01

324

Multilayer electromechanical composites with controlled piezoelectric coefficient distribution  

E-print Network

. This technique is an extremely versatile method to fabricate displacement actuators to fabricate monolithic ceramic parts with controlled material property gradients. To obtain a quantifiable method to optimize-2875 ABSTRACT We have fabricated multilayer electromechanical composites with controlled piezoelectric

Aksay, Ilhan A.

325

Investigation of lead-free thin films based on barium titanate for electrocaloric devices  

NASA Astrophysics Data System (ADS)

Lead-free thin films were synthesized by sol-gel for possible use in solid- state coolers. Surface morphology of the layers was obtained by atomic force microscopy (AFM). Electrophysical properties were investigated by impedance spectroscopy.

Abrashova, E. V.; Fominykh, A. K.

2014-10-01

326

Flux technology for lead-free alloys and its impact on cleaning  

Microsoft Academic Search

Flux technology for lead-free alloys differs considerably from that for eutectic Sn\\/Pb solder systems, mainly for soldering and cleaning purpose. For most of the lead-free solders, paste handling is not an issue. Although dust has not settled yet, it becomes clear that the flux needed should have higher flux capacity, higher oxygen barrier capability, and higher thermal stability. Halide-containing fluxes

Ning-Cheng Lee; Mike Bixenman

2002-01-01

327

Manufacturing feasibility of several lead-free solders for electronic assembly  

Microsoft Academic Search

This paper reports on a surface mount assembly evaluation with a series of existing lead-free solders. The wettability of the lead-free solders under investigation was measured by the meniscometer\\/wetting balance technique. This data provided an initial screening assessment of viable candidates for prototype development. Assembly process capability was based on visual, mechanical and metallurgical analyses of prototype circuit boards. The

A. M. Jackson; I. Artakl; P. T. Vianco

1994-01-01

328

Reduction of lead free solder aging effects using doped SAC alloys  

Microsoft Academic Search

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

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

2010-01-01

329

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

Microsoft Academic Search

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

Ji Wu; Michael G. Pecht

2006-01-01

330

Synthesis of tin, silver and their alloy nanoparticles for lead-free interconnect applications  

NASA Astrophysics Data System (ADS)

SnPb solders have long been used as interconnect materials in microelectronic packaging. Due to the health threat of lead to human beings, the use of lead-free interconnect materials is imperative. Three kinds of lead-free interconnect materials are being investigated, namely lead-free metal solders (SnAg, SnAgCu, etc.), electrically conductive adhesives (ECAs) and carbon nanotubes (CNTs). However, there are still limitations for the full utilization of these lead-free interconnect materials in the microelectronic packaging, such as higher melting point of lead-free metal solders, lower electrical conductivity of the ECAs and poor adhesion of CNTs to substrates. This thesis is devoted to the research and development of low processing temperature lead-free interconnect materials for microelectronic packaging applications with an emphasis on fundamental studies of nanoparticles synthesis, dispersion and oxidation prevention, and nanocomposites fabrication. Oxide-free tin (Sn), tin/silver (96.5Sn3.5Ag) and tin/silver/copper (96.5Sn3.0Ag0.5Cu) alloy nanoparticles with different sizes were synthesized by a low temperature chemical reduction method. Both size dependent melting point and latent heat of fusion of the synthesized nanoparticles were obtained. The nano lead-free solder pastes/composites created by dispersing the SnAg or SnAgCu alloy nanoparticles into an acidic type flux spread and wet on the cleaned copper surface at 220 to 230°C. This study demonstrated the feasibility of nano sized SnAg or SnAgCu alloy particle pastes for low processing temperature lead-free interconnect applications in microelectronic packaging.

Jiang, Hongjin

331

An investigation of lead-free thick-film resistors on LTCC substrates - preliminary results  

Microsoft Academic Search

The lead-free thick-film resistors with different ratios of conductive and glass phases were investigated. Four resistor materials with nominal sheet resistivities from 50 ohm\\/sq. to 50 kohm\\/sq. were prepared with different combinations of two lead-free glasses with reflow temperatures at 940°C and 1240°C, respectively, and two RuO2 powders (fine grained and coarse grained RuO2). Thick-film resistors were printed and fired

Marko Hrovat; Konrad Kielbasinski; Kostja Makarovic; Darko Belavic; Malgorzata Jakubowska

2011-01-01

332

Lead-free hunting rifle ammunition: product availability, price, effectiveness, and role in global wildlife conservation.  

PubMed

Proposals to end the use of lead hunting ammunition because of the established risks of lead exposure to wildlife and humans are impeded by concerns about the availability, price, and effectiveness of substitutes. The product availability and retail prices of different calibers of lead-free bullets and center-fire rifle ammunition were assessed for ammunition sold in the USA and Europe. Lead-free bullets are made in 35 calibers and 51 rifle cartridge designations. Thirty-seven companies distribute internationally ammunition made with lead-free bullets. There is no major difference in the retail price of equivalent lead-free and lead-core ammunition for most popular calibers. Lead-free ammunition has set bench-mark standards for accuracy, lethality, and safety. Given the demonstrated wide product availability, comparable prices, and the effectiveness of high-quality lead-free ammunition, it is possible to phase out the use of lead hunting ammunition world-wide, based on progressive policy and enforceable legislation. PMID:23288616

Thomas, Vernon George

2013-10-01

333

Electro-caloric effect in (Ba1-xCax)(Zr0.05Ti0.95)O3: A lead-free ferroelectric material  

NASA Astrophysics Data System (ADS)

Electro-caloric effect in lead-free (Ba1-xCax)(Zr0.05Ti0.95)O3 ferroelectric ceramics has been studied for x = 0.05, 0.08, and 0.10. The electro-caloric coefficient as high as 0.253 K mm/kV has been obtained near tetragonal-to-cubic phase transition for x = 0.08. This value is nearly the same as observed in lead-based ferroelectric materials. The higher value of electro-caloric coefficient at x = 0.08 is attributed to the higher polarization flexibility.

Singh, Gurvinderjit; Tiwari, V. S.; Gupta, P. K.

2013-11-01

334

Grain Orientation and Electrical Properties of Some Bismuth Layer-Structured Ferroelectrics for Lead-Free Piezoelectric Applications  

Microsoft Academic Search

The effects of grain orientation for some bismuth layer-structured ferroelectrics (BLSF) systems such as Bi4Ti3?xMxO12 [BITN-x] or [BITV-x] for M = Nb or V (0 ? x ? 0.2), Srm?3+xBi3? xTim - xTaxO3m +3 [SBTTm(x)] (m = 2, x = 1?2; m = 3, x = 0 ? 2), and Sr2(1? x)Ca2xBi4Ti5O18 [SCBT-x] (0 ? x ? 1) on electrical

Tadashi Takenaka; Hajime Nagata

2006-01-01

335

Radially sandwiched cylindrical piezoelectric transducer  

NASA Astrophysics Data System (ADS)

A new type of radially sandwiched piezoelectric short cylindrical transducer is developed and its radial vibration is studied. The transducer is composed of a solid metal disk, a radially polarized piezoelectric ceramic short tube and a metal tube. The radial vibrations of the solid metal disk, the radially polarized piezoelectric tube and the metal tube are analyzed and their electromechanical equivalent circuits are introduced. Based on the mechanical boundary conditions among the metal disk, the piezoelectric tube and the metal tube, a three-port electromechanical equivalent circuit for the radially sandwiched transducer is obtained and the frequency equation is given. The theoretical relationship of the resonance and anti-resonance frequencies and the effective electromechanical coupling coefficient with the geometrical dimensions is analyzed. The radial vibration of the sandwiched transducer is simulated by using two different numerical methods. It is shown that the analytical resonance and anti-resonance frequencies are in good agreement with the numerically simulated results. The transducer is expected to be used in piezoelectric resonators, actuators and ultrasonic radiators in ultrasonic and underwater sound applications.

Lin, Shuyu; Fu, Zhiqiang; Zhang, Xiaoli; Wang, Yong; Hu, Jing

2013-01-01

336

High temperature, high power piezoelectric composite transducers.  

PubMed

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

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

2014-01-01

337

High Temperature, High Power Piezoelectric Composite Transducers  

PubMed Central

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

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

2014-01-01

338

A Calculation of Physical Constants of Ceramic Barium Titanate  

Microsoft Academic Search

The dielectric, piezoelectric and elastic constants of polycrystalline ceramics at room temperature are calculated by averaging those values of single crystals on the assumption that the ceramic is composed of spherical crystallites. The calculated values are in good agreement with observed ones, showing that the piezoelectric effects in each single crystal (especially d15 at room temp.) play a great part

Masakazu Marutake

1956-01-01

339

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

PubMed Central

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

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

2014-01-01

340

Intermediate strain rate dependant mechanical properties for lead-free solders  

Microsoft Academic Search

Lead-free solders have strain rate dependent mechanical properties. In this work we report the elastic modulus and yield strength of several lead-free solder alloys at different strain rates. They are SnAgCu (with Ag 1 to 4% and Cu at 0.5%, namely SAC105, SAC205, SAC305 and SAC405), SAC-X (X=In, Ni and Bi), SnCu, SnCu-X and SnAg alloys. The intermediate strain rate

Luhua Xu; Kok Ee Tan; J. H. L. Pang

2010-01-01

341

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

DOEpatents

A lead-free percussion primer composition and a percussion cup containing e composition. The lead-free percussion primer composition is comprised of a mixture of about 45 wt % aluminum powder having an outer coating of aluminum oxide and molybdenum trioxide powder or a mixture of about 50 wt % aluminum powder having an outer coating of aluminum oxide and polytetrafluoroethylene powder. The aluminum powder, molybdenum trioxide powder and polytetrafluoroethylene powder has a particle size of 0.1 .mu.m or less, more preferably a particle size of from about 200-500 angstroms.

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

1998-01-01

342

Miniature piezoelectric triaxial accelerometer measures cranial accelerations  

NASA Technical Reports Server (NTRS)

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.

Deboo, G. J.; Rogallo, V. L.

1966-01-01

343

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

PubMed

Commercial lead-based piezoelectric materials raised worldwide environmental concerns in the past decade. Bi0.5Na0.5TiO3-based solid solution is among the most promising lead-free piezoelectric candidates; however, depolarization of these solid solutions is a longstanding obstacle for their practical applications. Here we use a strategy to defer the thermal depolarization, even render depolarization-free Bi0.5Na0.5TiO3-based 0-3-type composites. This is achieved by introducing semiconducting ZnO particles into the relaxor ferroelectric 0.94Bi0.5Na0.5TiO3-0.06BaTiO3 matrix. The depolarization temperature increases with increasing ZnO concentration until depolarization disappears at 30 mol% ZnO. The semiconducting nature of ZnO provides charges to partially compensate the ferroelectric depolarization field. These results not only pave the way for applications of Bi0.5Na0.5TiO3-based piezoceramics, but also have great impact on the understanding of the mechanism of depolarization so as to provide a new design to optimize the performance of lead-free piezoelectrics. PMID:25790446

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; Rödel, Jürgen; Cao, Wenwu; Chen, Yan-Feng

2015-01-01

344

Radial Field Piezoelectric Diaphragms  

NASA Technical Reports Server (NTRS)

A series of active piezoelectric diaphragms were fabricated and patterned with several geometrically defined Inter-Circulating Electrodes "ICE" and Interdigitated Ring Electrodes "ICE". When a voltage potential is applied to the electrodes, the result is a radially distributed electric field that mechanically strains the piezoceramic along the Z-axis (perpendicular to the applied electric field). Unlike other piezoelectric bender actuators, these Radial Field Diaphragms (RFDs) strain concentrically yet afford high displacements (several times that of the equivalent Unimorph) while maintaining a constant circumference. One of the more intriguing aspects is that the radial strain field reverses itself along the radius of the RFD while the tangential strain remains relatively constant. The result is a Z-deflection that has a conical profile. This paper covers the fabrication and characterization of the 5 cm. (2 in.) diaphragms as a function of poling field strength, ceramic thickness, electrode type and line spacing, as well as the surface topography, the resulting strain field and displacement as a function of applied voltage at low frequencies. The unique features of these RFDs include the ability to be clamped about their perimeter with little or no change in displacement, the environmentally insulated packaging, and a highly repeatable fabrication process that uses commodity materials.

Bryant, R. G.; Effinger, R. T., IV; Copeland, B. M., Jr.

2002-01-01

345

Piezoelectric trace vapor calibrator  

NASA Astrophysics Data System (ADS)

The design and performance of a vapor generator for calibration and testing of trace chemical sensors are described. The device utilizes piezoelectric ink-jet nozzles to dispense and vaporize precisely known amounts of analyte solutions as monodisperse droplets onto a hot ceramic surface, where the generated vapors are mixed with air before exiting the device. Injected droplets are monitored by microscope with strobed illumination, and the reproducibility of droplet volumes is optimized by adjustment of piezoelectric wave form parameters. Complete vaporization of the droplets occurs only across a 10°C window within the transition boiling regime of the solvent, and the minimum and maximum rates of trace analyte that may be injected and evaporated are determined by thermodynamic principles and empirical observations of droplet formation and stability. By varying solution concentrations, droplet injection rates, air flow, and the number of active nozzles, the system is designed to deliver—on demand—continuous vapor concentrations across more than six orders of magnitude (nominally 290fg/lto1.05?g/l). Vapor pulses containing femtogram to microgram quantities of analyte may also be generated. Calibrated ranges of three explosive vapors at ng/l levels were generated by the device and directly measured by ion mobility spectrometry (IMS). These data demonstrate expected linear trends within the limited working range of the IMS detector and also exhibit subtle nonlinear behavior from the IMS measurement process.

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

2006-08-01

346

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

PubMed

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

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

347

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...

348

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...

349

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

NASA Astrophysics Data System (ADS)

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

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

2014-09-01

350

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% ...

351

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

Microsoft Academic Search

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

Tsuguto Takeuchi; Toshihiko Tani; Yasuyoshi Saito

1999-01-01

352

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

E-print Network

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

Ha, Dong S.

353

Synthesis of piezoelectric materials by ultrasonic assisted hydrothermal method  

NASA Astrophysics Data System (ADS)

Hydrothermal method enables to synthesize high quality piezoelectric materials. To shorten the reaction time and to get higher quality materials, we propose an ultrasonic irradiation to the solution during the hydrothermal method. We named it ultrasonic assisted hydrothermal method (UAHTM). We have synthesized lead-free piezoelectric material and PZT thin film and the effect of UAHTM have been confirmed. In this study, we tried to improve UAHTM. First, to generate powerful and stable ultrasonic irradiation at high temperature on UAHTM, we developed a new transducer using LiNbO3 single crystal. Second, to prevent contamination to the materials, A Teflon cover on the tip of transducer was attached.

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

2012-05-01

354

Dielectrophoretically structured piezoelectric composites with high aspect ratio piezoelectric particles inclusions  

NASA Astrophysics Data System (ADS)

Piezoelectric composites were prepared by dielectrophoretic alignment of high aspect ratio piezoelectric particles in a thermosetting polymer matrix. A high level of alignment was achieved in the cured composite from a resin containing randomly oriented high aspect ratio particles. Upon application of an electric field during curing of the resin, the particles were found to rotate with their long axes in the direction of the electric field, before coalescing to form chains. The dielectric and piezoelectric properties of the structured composites are well described by an analytical model for composites containing particles arranged into chains. The influence of degree of rotation and aspect ratio of the individual particles as well as their spacing is described with this model. The results correlate with the experimental values for both permittivity and piezoelectric constants in the poling direction. Dielectric and piezoelectric properties were significantly improved with respect to randomly dispersed piezoelectric ceramic powder-polymer composites and the maximum g33 was shifted to a lower volume fraction. The results could have implications for development of dielectric and piezoelectric (nano-)fiber composites for dielectrics such as embedded capcitors, as well as piezoelectrics for sensing and energy harvesting applications.

van den Ende, D. A.; van Kempen, S. E.; Wu, X.; Groen, W. A.; Randall, C. A.; van der Zwaag, S.

2012-06-01

355

Measurement of elastic modulus and ultrasonic wave velocity by piezoelectric resonator  

NASA Astrophysics Data System (ADS)

A piezoelectric ceramic resonator is used for the ‘electrical’ measurement of elastic properties, i.e. Young’s modulus and ultrasonic wave velocity in metallic materials. Piezoelectric response is precisely calculated for the piezoelectric ceramic ring fixed at the end of a metallic rod. The piezoelectric ring serves as both an actuator as well as a sensor. The experimental setup and method of measurement using higher overtones is explained in detail and practically demonstrated for a set of different metallic materials. Young’s moduli and ultrasonic wave velocities are measured within 3% relative error. The presented method is suitable for an advanced engineering class or physics laboratory training.

Erhart, Ji?í

2015-01-01

356

Flux technology for lead-free alloys and its impact on cleaning  

Microsoft Academic Search

Cleaning flux residue of lead-free solder pastes is more challenging than that of Sn\\/Pb systems. This is primarily due to (1) higher reflow temperature, (2) higher flux capacity, therefore higher flux-induced side reactions, (3) more tin-salts formation. The cleanability decreases from no-clean soft-residue fluxes to water washable fluxes to no-clean hard residue fluxes. Improvement in cleanability may link to improvement

Ning-Cheng Lee; M. Bixenman

2002-01-01

357

C3F8\\/O plasma treatment of lead free solders for fluxless soldering  

Microsoft Academic Search

Fluorination of Sn-3.6 wt%Ag lead free solder was achieved using a C3F8 and O plasma treatment. X-ray photoelectron spectroscopy (XPS) was used to analysis fluorinated surface before and after oxidation in air. Three layers were existed perpendicular to the surface after plasma irradiation. The top surface layer was a complex mixture of absorptions (CFx groups such as CF, CF2, CF3

Naoe Hosoda; Tadatomo Suga

2003-01-01

358

Nano-Scale Mechanical Responses of SnAg Based Lead-free Solders  

Microsoft Academic Search

The mechanical properties of the Sn-3.5Ag lead-free solder alloys were characterized in different size scales by nanoindentation technology. Some of the principle mechanical properties, such as Mayer's hardness, reduced Young's modulus and the strain rate sensitivity index were assessed. In particular, the strain rate sensitivity index is extracted from the creep deformation of the solder alloys at the dwell time

Feng Gao; H. Nishikawa; T. Takemoto

2007-01-01

359

THERMOMECHANICAL ANALYSIS OF A CHIP SCALE PACKAGE (CSP) USING LEAD FREE AND LEAD CONTAINING SOLDER MATERIALS  

Microsoft Academic Search

This work is intended to provide a quantitative estimation of the accumulated inelastic strain of two different lead free solder alloys, namely, Sn3.5Ag and Sn3.8Ag0.5Cu. The eutectic Sn37Pb solder is also considered to establish a baseline. Thermomechanical stress and strain analysis was conducted on a Chip Scale Package (CSP). The solder joint fatigue was modeled for two typical temperature cycling

M. GONZALEZ; B. VANDEVELDE; E. BEYNE

360

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

Microsoft Academic Search

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

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

2006-01-01

361

Lead-free solder material characterization for thermo-mechanical modeling  

Microsoft Academic Search

Systematic mechanical characterization has been done on lead-free solder alloys, i.e., SAC105, SAC205, SAC305, SAC105Ni0.02, and SAC105Ni0.05 as promising alternatives of SnPb solder. Solder joints in service stay in high homologous temperatures that have profound effects on mechanical properties such as creep and the apparent elastic modulus. Mechanical deformation behaviors of bulk solder alloys at temperatures between 298 K and

Edith S. W. Poh; W. H. Zhu; X. R. Zhang; C. K. Wang; Anthony Y. S. Sun; H. B. Tan

2008-01-01

362

Development of Sn–Zn lead-free solders bearing alloying elements  

Microsoft Academic Search

Sn–Zn solder alloys have been considered as one of the more attractive lead-free solders since it can easily replace Sn–Pb\\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

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

363

Microstructural evolution of Sn-Zn based lead free solders after temperature and humid atmosphere exposure  

Microsoft Academic Search

The Sn-Zn based lead free solders appear to be an attractive alternative with a melting temperature that is relatively close to eutectic Sn-Pb. The addition of bismuth improves wettability of Sn-Zn alloy and aluminum is found to improve the oxidation resistance of the eutectic Sn-Zn solder. The objective of this study is to explore the degradation of Sn-Zn system solders

Peng Sun; Cristina Andersson; Xicheng Wei; Zhaonian Cheng; Dongkai Shangguan; Johan Liu

2005-01-01

364

Reliability of lead-free interconnections under consecutive thermal and mechanical loadings  

Microsoft Academic Search

To simulate more realistically the effects of strains and stresses on the reliability of portable electronic products, lead-free\\u000a test assemblies were thermally cycled (?45?C\\/+125?C, 15-min. dwell time, 750 cycles) or isothermally annealed (125?C, 500\\u000a h) before the standard drop test. The average number of drops to failure increased when the thermal cycling was performed\\u000a before the drop test (1,500 G

T. T. Mattila; J. K. Kivilahti

2006-01-01

365

Analysis of ring and plug shear strengths for comparison of lead-free solders  

Microsoft Academic Search

The drive to replace the use of toxic lead metal and its alloys has spurred the development of many new lead-free solder alloys.\\u000a Moreover, current leaded solders lack shear strength, resistance to creep and to thermal-mechanical fatigue. Solder that exhibits\\u000a enhancements of these properties and retains solderability is crucial in applications where the solder joints are subjected\\u000a to thermal cycling,

J. C. Foley; A. Gickler; F. H. Leprevost; D. Brown

2000-01-01

366

NASA-DoD Lead-Free Electronics Project: Vibration Test  

NASA Technical Reports Server (NTRS)

Vibration testing was conducted by Boeing Research and Technology (Seattle) for the NASA-DoD Lead-Free Electronics Solder Project. This project is a follow-on to the Joint Council on Aging Aircraft/Joint Group on Pollution Prevention (JCAA/JG-PP) Lead-Free Solder Project which was the first group to test the reliability of lead-free solder joints against the requirements of the aerospace/miLItary community. Twenty seven test vehicles were subjected to the vibration test conditions (in two batches). The random vibration Power Spectral Density (PSD) input was increased during the test every 60 minutes in an effort to fail as many components as possible within the time allotted for the test. The solder joints on the components were electrically monitored using event detectors and any solder joint failures were recorded on a Labview-based data collection system. The number of test minutes required to fail a given component attached with SnPb solder was then compared to the number of test minutes required to fail the same component attached with lead-free solder. A complete modal analysis was conducted on one test vehicle using a laser vibrometer system which measured velocities, accelerations, and displacements at one . hundred points. The laser vibrometer data was used to determine the frequencies of the major modes of the test vehicle and the shapes of the modes. In addition, laser vibrometer data collected during the vibration test was used to calculate the strains generated by the first mode (using custom software). After completion of the testing, all of the test vehicles were visually inspected and cross sections were made. Broken component leads and other unwanted failure modes were documented.

Woodrow, Thomas A.

2010-01-01

367

Effect of cement-polymer ratio on 1-3 piezoelectric composites  

NASA Astrophysics Data System (ADS)

A 1-3 type piezoelectric composite was fabricated by cut-filling technique. The effects of cement-polymer ratio on piezoelectric and dielectric properties of the composites were analyzed. The results show that piezoelectric strain factor d33 and piezoelectric voltage factor g33 exhibit the trend of decrease initially and then increase with increasing cement-polymer ratio. With the increase of cement-polymer ratio, the dielectric factor ?r and dielectric loss tan? of the composites increase initially and then decrease. Comparing with pure piezoelectric ceramic, the mechanical quality factor Qm decreases obviously. Acoustic impedance Z is about 9 M raly, which is matching with concrete.

Guo, Lili; Xu, Dongyu; Huang, Shifeng

2009-07-01

368

www.ceramics.org | American Ceramic Society Bulletin, Vol. 92, No. 118 By Paul G. Evans and Rebecca J. Sichel-Tissot  

E-print Network

www.ceramics.org | American Ceramic Society Bulletin, Vol. 92, No. 118 By Paul G. Evans and Rebecca of piezoelectric ceramic thin films There has been rapid development in the precision with which ferroelectric mate,2 Ferroelectric thin-film materi- als belong to the broad category of electronic ceramics, and they find

Evans, Paul G.

369

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

E-print Network

to transition their products to lead-free as tin-lead solder finish electronic parts become unavailable) a qualified mixed assembly of tin-lead and lead-free parts assembled with tin- lead solder. In order to aide in qualifying the solder as well as testing the reliability of the parts reprocessed using the new solder. Once

Sandborn, Peter

370

Piezoelectricity and aging effects in the PMN-PT system  

Microsoft Academic Search

PMN ceramics present piezoelectricity under an applied dc bias field. The relative dielectric permittivity varies, in general, over a wide range of values of the applied dc electric field. The purpose of this work is to study the induced piezoelectricity effect produced by an applied dc electric field in the 2.7PMN-0.1PT system assuming that the relative dielectric permittivity is a

J. Portelles; J. M. Siqueiros; A. Fundora; G. Rosario; R. Machorro; G. Hirata; F. Calderón

1999-01-01

371

Large piezoelectric effects in charged, heterogeneous fluoropolymer electrets  

Microsoft Academic Search

.   Large piezoelectric d33 coefficients around 600 pC\\/N are found in corona-charged non-uniform electrets consisting of elastically “soft” (microporous\\u000a polytetrafluoroethylene PTFE) and “stiff” (perfluorinated cyclobutene PFCB) polymer layers. The piezoelectric activity of\\u000a the two-layer fluoropolymer stack exceeds the d33 coefficient of the ferroelectric ceramic lead zirconate titanate (PZT) by more than a factor of two and that of the ferroelectric\\u000a polymer

G. S. Neugschwandtner; R. Schwödiauer; S. Bauer-Gogonea; S. Bauer

2000-01-01

372

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

PubMed Central

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

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

2013-01-01

373

Piezoelectric properties of lithium modified silver niobate perovskite single crystals  

NASA Astrophysics Data System (ADS)

We report the growth and the piezoelectric properties of lead-free perovskite single crystals of Ag1-xLixNbO3. It possesses a rhombohedral structure with high ferroelectric phase transition (Tc=548K for x =0.086) and large spontaneous polarization (Ps˜40?C/cm2 for x =0.062) along the ?111?c direction of pseudocubic perovskite structure for x >0.05-0.06. High quasistatic d33˜210pC/N and low dielectric constant have lead to a very large value of piezoelectric voltage constant g33˜53.9×10-3Vm/N for the ?001?c-cut crystal of this simple perovskite. It has been shown that Li substitution might enhance the piezoelectric coefficient of the crystal. The excellent piezo-/ferroelectricity of this system are considered to be facilitated by the strong polarization nature of both Ag and Li in the perovskite structure. Our findings may stimulate further interests in the development of lead-free piezoelectrics.

Fu, Desheng; Endo, Makoto; Taniguchi, Hiroki; Taniyama, Tomoyasu; Koshihara, Shin-ya; Itoh, Mitsuru

2008-04-01

374

Creep properties of Sn8Mass%Zn3Mass%Bi lead-free alloy  

Microsoft Academic Search

The creep properties of Sn-8mass%Zn-3mass%Bi were investigated and compared with those of other lead-free solders and a Sn-Pb\\u000a eutectic solder. The creep rupture time decreases with increasing the initial stress and the temperature. For high stresses,\\u000a the linear relationships between the minimum strain rate and the applied stress were observed. The stress exponents were examined\\u000a to be 9.3, 7, and

Ikuo Shohji; Colin Gagg; William J. Plumbridge

2004-01-01

375

Electrical poling below coercive field for large piezoelectricity  

NASA Astrophysics Data System (ADS)

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.

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

2013-03-01

376

Analysis and Modeling of a Piezoelectric Transformer in High Output Voltage Applications  

E-print Network

Analysis and Modeling of a Piezoelectric Transformer in High Output Voltage Applications Gregory-Piezoelectric transformers (PZT) can be used advantageously in high output voltage DC-DC converters. In such applications voltage isolation of the ceramic materials used to build PZTs. This advantage is especially important when

377

Logarithmic frequency dependence of the piezoelectric effect due to pinning of ferroelectric-ferroelastic domain walls  

Microsoft Academic Search

Pinning of the ferroelastic-ferroelectric domain walls on randomly distributed defects in ferroelectric ceramics leads to a field dependence of the piezoelectric coefficient that is analogous to the Rayleigh law for magnetic susceptibility. It is shown in this paper that the piezoelectric coefficient of a lead zirconate titanate ferroelastic-ferroelectric system depends linearly on the logarithm of the frequency of the field.

Dragan Damjanovic

1997-01-01

378

Space Charge Effect in Lead Zirconate Titanate Ceramics Caused by the Addition of Impurities  

Microsoft Academic Search

Lead zirconate titanate ceramics containing metal oxides as impurities are subjected to poling, in order to give rise to piezoelectric activity, at various temperatures. Impurities contained in the ceramics are found to be divided into three groups according to their effects on poling temperatures. (1) When the amounts are small, piezoelectric activity is lowered by poling at low temperatures, but

Masao Takahashi

1970-01-01

379

Enhanced lateral electromechanical coupling in lead-titanate-rod\\/polymer piezoelectric composites  

Microsoft Academic Search

Although modified lead-titanate ceramics exhibit a negligible d31 piezoelectric coefficient, piezoelectric-rod\\/polymer-matrix composites made from them exhibit a substantial d31. A theoretical analysis shows that the composite's enhanced d31 coefficient arises from lateral stress on the polymer phase being transferred to a longitudinal stress along the ceramic rods by the Poisson effect in the polymer, thus producing a charge through the

WALLACE ARDEN SMITH; AVNER A. SHAULOV; ROBERT Y. TING

1988-01-01

380

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

NASA Astrophysics Data System (ADS)

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.

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

2014-06-01

381

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

NASA Astrophysics Data System (ADS)

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.

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

2012-05-01

382

Nanoscale Insight into Lead-Free BNT-BT-xKNN  

SciTech Connect

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.

Dittmer, Robert [Technische Universitat Darmstadt, Germany; Jo, Wook [Technische Universitat Darmstadt, Germany; Rödel, Jürgen [Technische Universitat Darmstadt, Germany; Kalinin, Sergei V [ORNL

2012-01-01

383

Theoretical prediction of new high-performance lead-free ferroelectrics  

Microsoft Academic Search

We predict the occurence of large ferroelectric polarization and piezoelectricity in the hypothetical perovskite-structure oxides, bismuth aluminate (BiAlO3) and bismuth gallate (BiGaO3), using density functional theory within the local density approximation. We show that BiGaO3 will have a similar structure to PbTiO3, although with much stronger tetragonal distortion and therefore improved ferroelectric properties. Likewise, BiAlO3 shares structural characteristics with antiferrodistortive

Pio Baettig; Richard Lesar; Umesh Waghmare; Nicola A. Spaldin

2005-01-01

384

Piezoelectric drive circuit  

DOEpatents

A piezoelectric motor drive circuit is provided which utilizes the piezoelectric elements as oscillators and a Meacham half-bridge approach to develop feedback from the motor ground circuit to produce a signal to drive amplifiers to power the motor. The circuit automatically compensates for shifts in harmonic frequency of the piezoelectric elements due to pressure and temperature changes. 7 figs.

Treu, C.A. Jr.

1999-08-31

385

Piezoelectric drive circuit  

DOEpatents

A piezoelectric motor drive circuit is provided which utilizes the piezoelectric elements as oscillators and a Meacham half-bridge approach to develop feedback from the motor ground circuit to produce a signal to drive amplifiers to power the motor. The circuit automatically compensates for shifts in harmonic frequency of the piezoelectric elements due to pressure and temperature changes.

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

1999-08-31

386

"Mighty Worm" Piezoelectric Actuator  

NASA Technical Reports Server (NTRS)

"Mighty Worm" piezoelectric actuator used as adjustable-length structural member, active vibrator or vibration suppressor, and acts as simple (fixed-length) structural member when inactive. Load force not applied to piezoelectric element in simple-structural-member mode. Piezoelectric element removed from load path when not in use.

Bamford, Robert M.; Wada, Ben K.; Moore, Donald M.

1994-01-01

387

Experimental investigation of alternative pre-stress components for a 3-1 connectivity multilayer piezoelectric-polymer composite ultrasonic transducer  

Microsoft Academic Search

The most popular configuration for piezoelectric-polymer composites has pillars of piezoelectric ceramic supported by a polymer matrix and material with this structure is now widely available commercially. However, it has significant disadvantages for use in multilayer devices for non-mass-loaded operation below approximately 50 kHz. An alternative configuration is therefore reported here, in which interconnected fingers of piezoelectric ceramic surround polymer

D. Robertson; S. Cochran

2002-01-01

388

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

SciTech Connect

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

Wu Jiagang; Wang, John [Department of Materials Science and Engineering, Faculty of Engineering, National University of Singapore, Singapore 117574 (Singapore)

2009-09-15

389

Application of lead-free eutectic SnAg solder in no-clean thick film electronic modules  

Microsoft Academic Search

As part of the lead-free solder development process currently underway, this paper presents the evaluation of the lead-free Sn-Ag solder for use in no-clean thick film electronics packages. The Sn-Ag (96.5\\/3.5 wt%) eutectic solder alloy, with a no clean flux system, is the focus of this study. Based on studies of metallurgical interactions, the conductor\\/substrate adhesion, and electromigration\\/dendritic growth, it

Dongkai Shangguan; Achyuta Achari; Wells Green

1994-01-01

390

Effect of Lead-Free Soldering on Key Material Properties of FR4 Printed Circuit Board Laminates  

Microsoft Academic Search

The transition to lead-free soldering of printed circuit boards (PCBs) using solder alloys such as SnAgCu has resulted in higher temperature exposures during assembly compared with eutectic SnPb solders. The knowledge of PCB laminate material properties and their dependence on the material constituents, combined with their possible variations due to lead-free soldering temperature exposures, is an essential input in the

Ravikumar Sanapala; Bhanu Sood; Diganta Das; Michael Pecht

2009-01-01

391

Fracture Toughness Enhancements in Carbon Nanotube Reinforced Ceramic Matrix Composites  

NASA Technical Reports Server (NTRS)

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

Hurst, Janet

2003-01-01

392

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

NASA Astrophysics Data System (ADS)

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.

Anson, Scott J.

393

Thermal diffusivity determination in tin-based lead-free solder alloys  

NASA Astrophysics Data System (ADS)

The thermal diffusivities of three Sn-based solder alloys (Sn-3%wtAg-0.5%wtCu, Sn-4%wtAg-0.5%wtCu, and Sn-3.8%wtAg-0.7%wtCu), were determined from room temperature to up to 120°C. In addition to the lead-free alloy, the thermal diffusivity of the binary constituent alloys Cu6Sn5 and Ag 3Sn were measured over the same temperature range. For these studies, cylindrical samples of 6cm diameter and 1cm thickness were used. The temperature and the resulting thermal diffusivities were measured at seven different points of each sample in 5--10°C intervals. The heat pulse used leads to a 3--5°C temperature increase during the measurement. The thermal diffusivity between each two points is calculated using the logarithm gradient of the measured temperature difference between each pair versus time. The thermal diffusivity of the binary alloys showed a slight increase in thermal diffusivity with increasing temperature. This is opposite behavior from Sn matrix that has a rather strong decrease in thermal diffusivity with increasing temperature. In the lead-free alloys substantial differences were observed in the thermal diffusivity in both the different locations and sample temperatures. In some cases these differences were close to 300%. COMSOL Multiphysics was used to simulate the experiment and the heat flow in different phases in the sample and the effects of size, distribution and direction of the intermetallic phases and grain boundary mismatch on the overall thermal diffusivity. The experimental differences observed between the thermal diffusivities of different measurement pairs in each sample are explained by the study of the microstructure and the presence of intermetallic compounds and dislocations in the structure.

Mohammad Alipour, Manijeh

394

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

PubMed

We introduce a novel lead-free ferroelectric thin film (1-x)BaTiO3-xBa(Cu1/3Nb2/3)O3 (x = 0.025) (BT-BCN) integrated on to HfO2 buffered Si for non-volatile memory (NVM) applications. Piezoelectric force microscopy (PFM), x-ray diffraction, and high resolution transmission electron microscopy were employed to establish the ferroelectricity in BT-BCN thin films. PFM study reveals that the domains reversal occurs with 180° phase change by applying external voltage, demonstrating its effectiveness for NVM device applications. X-ray photoelectron microscopy was used to investigate the band alignments between atomic layer deposited HfO2 and pulsed laser deposited BT-BCN films. Programming and erasing operations were explained on the basis of band-alignments. The structure offers large memory window, low leakage current, and high and low capacitance values that were easily distinguishable even after ~10(6)?s, indicating strong charge storage potential. This study explains a new approach towards the realization of ferroelectric based memory devices integrated on Si platform and also opens up a new possibility to embed the system within current complementary metal-oxide-semiconductor processing technology. PMID:25683062

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

2015-01-01

395

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

NASA Astrophysics Data System (ADS)

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.

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

2015-02-01

396

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

PubMed Central

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

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

2015-01-01

397

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

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.

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

398

Piezoelectric Rod Micro Ultrasonic Motor with Shear-bending Modes  

Microsoft Academic Search

In this paper we propose a new mechanism for exciting shear-bending vibration in a piezoelectric ceramic rod. A mini-ultrasonic motor prototype with this concept was designed. Both finite element method (FEM) analysis and experimental results demonstrate the concept.

Cunyue Lu; Tieying Zhou; Yu Chen; Kai Lu

2006-01-01

399

Consideration of impedance matching techniques for efficient piezoelectric energy harvesting.  

PubMed

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

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

2007-09-01

400

High power characteristics at antiresonance frequency of piezoelectric transducers  

Microsoft Academic Search

First in this paper, the loss in piezoelectric ceramics is described. Antiresonance is the vibration under constant D (electric displacement) driving, and therefore electro-mechanical loss becomes almost zero: resonance is the vibration under constant E (electric field) driving, and then there exists large electro-mechanical loss. The relations between antiresonance and the constant D driving are explained. Next, a method of

Seiji Hirose; Manabu Aoyagi; Yoshiro Tomikawa; Sadayuki Takahashi; Kenji Uchino

1996-01-01

401

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

NASA Astrophysics Data System (ADS)

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

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

2014-09-01

402

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

NASA Astrophysics Data System (ADS)

The trend of electronic packaging is to package the chips and the associated interconnections in a compact way that allows high speed operation; that allows for sufficient heat removal; that can withstand the thermal cycling associated with the turning on and turning off of the circuits; and that protects the circuits from environmental attack. These goals require that flip chip solder joints have higher resistance to electromigration, stronger mechanical property to sustain thermal mechanical stress, and are lead-free materials to satisfy environment and health concern. With lots of work on chemical reaction, electromigration and mechanical study in flip chip solder joints, however, the interaction between different driving forces is still little known. As a matter of fact, the combination study of chemical, electrical and mechanical is more and more significant to the understanding of the behavior of flip chip solder joints. In this dissertation, I developed one dimensional Cu (wire)-eutectic SnAgCu(ball)-Cu(wire) structure to investigate the interaction between electrical and mechanical force in lead-free solder joints. Electromigration was first conducted. The mechanical behaviors of solder joints before, after, and during electromigration were examined. Electrical current and mechanical stress were applied either in serial or in parallel to the solder joints. Tensile, creep, and drop tests, combined with different electrical current densities (1˜5x10 3A/cm2) and different stressing time (3˜144 hours), have been performed to study the effect of electromigration on the mechanical behavior of solder joints. Nano-indentation test was conducted to study the localized mechanical property of IMC at both interfaces in nanometer scale. Fracture images help analyze the failure mechanism of solder joints driven by both electrical and mechanical forces. The combination study shows a strain build-up during electromigration. Furthermore, a ductile-to-brittle transition in flip chip solder joints induced by electromigration is observed, in which the fracture position migrates from the middle to the cathode interface of the joint with increasing current density and time. The transition is explained by the polarity effect of electromigration, particular due to the accumulation of vacancies at the cathode interface.

Ren, Fei

403

Design, Manufacturing and Characterization of Functionally Graded Flextensional Piezoelectric Actuators  

NASA Astrophysics Data System (ADS)

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

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

2013-03-01

404

A piezoelectric transformer  

NASA Technical Reports Server (NTRS)

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

Won, C. C.

1993-01-01

405

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

NASA Technical Reports Server (NTRS)

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.

Sampson, Michael J.

2008-01-01

406

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

NASA Astrophysics Data System (ADS)

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

Nguyen, Van Luong; Kim, Ho-Kyung

2014-09-01

407

SHPB tests for mechanical behavior of lead-free solder alloys  

NASA Astrophysics Data System (ADS)

Dynamic behavior of solder joints in microelectronic packages is key issue for drop/impact reliability design of mobile electronic products. The dynamic mechanical behavior of 63Sn37Pb, 96.5Sn3.5Ag and 96.5Sn3.0Ag0.5Cu at high strain rates have been investigated by using the split Hopkinson pressure/tension bar testing technique (SHPB). Stress-strain relations of the three solders were obtained at strain rates of 600s-1, 1200s-1 and 2200s-1, respectively. The experimental results show that the lead-free solders are strongly strain rate dependent. 96.5Sn3.5Ag is the most sensitive to strain rate, while 63Sn37Pb is the least. 96.5Sn3.0Ag0.5Cu has the greatest yield stress and tensile strength. Relations of the yield stress and the tensile strength of the solders with strain rate were fitted.

Qin, Fei; An, Tong; Chen, Na

2008-11-01

408

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

NASA Astrophysics Data System (ADS)

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

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

2012-02-01

409

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

NASA Astrophysics Data System (ADS)

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 (<175°C). 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.

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

2013-07-01

410

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

PubMed

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

Fujiuchi, Yukiko; Morita, Takeshi

2014-10-01

411

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

NASA Astrophysics Data System (ADS)

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.

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

2013-12-01

412

Microstructure Characterization Of Lead-Free Solders Depending On Alloy Composition  

NASA Astrophysics Data System (ADS)

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.

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

2010-11-01

413

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

NASA Astrophysics Data System (ADS)

The tribological properties of a centrifugally cast lead-free copper alloy (C90300), containing an average of 13 vol pct graphite particles (5 µm), 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

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

2001-08-01

414

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

Microsoft Academic Search

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

Debasish Sarkar; Min Cheol Chu; Seong Jai Cho

415

Precipitation of Zirconia Phase in Niobium-Modified Ceramics of Lead Zirconate-Titanate  

Microsoft Academic Search

The piezoelectric performances of lead ziroconate-titanate ceramics are much improved by an addition of niobia, and they are called the ``modified'' ceramics by the staffs of the Clevite Research Center. Microscopic observation of these ceramics shows many pink precipitates segregating out of the grains. These parts are luminescent in the incidence of electron beam. The electron probe microanalysis reveals that

Takuro Ikeda; Yoichi Tanaka; Takako Ayakawa; Haruo Noake

1964-01-01

416

Adaptive piezoelectric shunt damping  

Microsoft Academic Search

Piezoelectric shunt damping systems reduce structural vibration by shunting an attached piezoelectric transducer with an electrical impedance. Current impedance designs result in a coupled electrical resonance at the target modal frequencies. In practical situations, variation in structural load or environmental conditions can result in significant changes in the structural resonance frequencies. This variation can severely reduce shunt damping performance as

Andrew J. Fleming; S. O. Reza Moheimani

2002-01-01

417

Active piezoelectric damping composites  

Microsoft Academic Search

Patches of active piezoelectric damping composites (APDC) consisting of piezoelectric rods, which are obliquely embedded across the thickness of viscoelastic damping matrix, are presented as a viable candidate for smart actuation. In this configuration, activation of the piezo-rods simultaneously enhances both the shear and compression damping characteristics of the smart composite actuator. With such active\\/passive capabilities, the APDC presents an

A. Baz; A. Tempia

2004-01-01

418

High Strain, /001S Textured 0.675Pb(Mg1/3Nb2/3)O30.325PbTiO3 Ceramics: Templated Grain Growth and Piezoelectric Properties  

E-print Network

-McKinstry Department of Materials Science and Engineering, Materials Research Institute, The Pennsylvania StateHigh Strain, /001S Textured 0.675Pb(Mg1/3Nb2/3)O3­0.325PbTiO3 Ceramics: Templated Grain Growth­ 0.325PbTiO3 (PMN­32.5PT) ceramics were textured (grain- oriented) in the /001S

Messing, Gary L.

419

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

SciTech Connect

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.

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

2014-06-01

420

Portfolio: Ceramics.  

ERIC Educational Resources Information Center

Describes eight art activities using ceramics. Elementary students created ceramic tiles to depict ancient Egyptian and medieval European art, made ceramic cookie stamps, traced bisque plates on sketch paper, constructed clay room-tableaus, and designed clay relief masks. Secondary students pit-fired ceramic pots and designed ceramic Victorian…

Hardy, Jane; And Others

1982-01-01

421

Microstructure basis for strong piezoelectricity in Pb-free Ba(Zr0.2Ti0.8)O3-(Ba0.7Ca0.3)TiO3 ceramics  

NASA Astrophysics Data System (ADS)

In this letter, we use transmission electron microscopy to study the microstructure feature of recently reported Pb-free piezoceramic Ba(Zr0.2Ti0.8)O3-x(Ba0.7Ca0.3)TiO3 across its piezoelectricity-optimal morphotropic phase boundary (MPB) by varying composition and temperature, respectively. The domain structure evolutions during such processes show that in MPB regime, the domains become miniaturized down to nanometer size with a domain hierarchy, which coincides with the d33-maximum region. Further convergent beam electron diffraction measurement shows that rhombohedral and tetragonal crystal symmetries coexist among the miniaturized domains. Strong piezoelectricity reported in such a system is due to easy polarization rotation between the coexisting nano-scale tetragonal and rhombohedral domains.

Gao, Jinghui; Xue, Dezhen; Wang, Yu; Wang, Dong; Zhang, Lixue; Wu, Haijun; Guo, Shengwu; Bao, Huixin; Zhou, Chao; Liu, Wenfeng; Hou, Sen; Xiao, Ge; Ren, Xiaobing

2011-08-01

422

Intermetallics Characterization of Lead-Free Solder Joints under Isothermal Aging  

NASA Astrophysics Data System (ADS)

Solder interconnect reliability is influenced by environmentally imposed loads, solder material properties, and the intermetallics formed within the solder and the metal surfaces to which the solder is bonded. Several lead-free metallurgies are being used for component terminal plating, board pad plating, and solder materials. These metallurgies react together and form intermetallic compounds (IMCs) that affect the metallurgical bond strength and the reliability of solder joint connections. This study evaluates the composition and extent of intermetallic growth in solder joints of ball grid array components for several printed circuit board pad finishes and solder materials. Intermetallic growth during solid state aging at 100°C and 125°C up to 1000 h for two solder alloys, Sn-3.5Ag and Sn-3.0Ag-0.5Cu, was investigated. For Sn-3.5Ag solder, the electroless nickel immersion gold (ENIG) pad finish was found to result in the lowest IMC thickness compared to immersion tin (ImSn), immersion silver (ImAg), and organic solderability preservative (OSP). Due to the brittle nature of the IMC, a lower IMC thickness is generally preferred for optimal solder joint reliability. A lower IMC thickness may make ENIG a desirable finish for long-life applications. Activation energies of IMC growth in solid-state aging were found to be 0.54 ± 0.1 eV for ENIG, 0.91 ± 0.12 eV for ImSn, and 1.03 ± 0.1 eV for ImAg. Cu3Sn and Cu6Sn5 IMCs were found between the solder and the copper pad on boards with the ImSn and ImAg pad finishes. Ternary (Cu,Ni)6Sn5 intermetallics were found for the ENIG pad finish on the board side. On the component side, a ternary IMC layer composed of Ni-Cu-Sn was found. Along with intermetallics, microvoids were observed at the interface between the copper pad and solder, which presents some concern if devices are subject to shock and vibration loading.

Choubey, Anupam; Yu, Hao; Osterman, Michael; Pecht, Michael; Yun, Fu; Yonghong, Li; Ming, Xu

2008-08-01

423

Ceramic actuators - Principles and applications  

NASA Astrophysics Data System (ADS)

Piezoelectric and electrostrictive actuators for electromechanical work have applications that fall into the broad categories of positioners, motors, and vibration suppressors. These ceramic actuators have displacements of up to several tens of microns, which can be controlled with a precision of +/- 10 microns, as well as response speeds of the order of 10 microsec and generative forces as large as 400 kgf/sq cm. Their driving power is typically an order of magnitude smaller than that of electromagnetic motors. Attention is given to the multilayer and bimorph types of ceramic actuators that are currently the most often used in applications of this technology.

Uchino, Kenji

1993-04-01

424

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

NASA Astrophysics Data System (ADS)

Lead free potassium sodium niobate (K0.5Na0.5NbO3) ceramic powders were synthesized by colloidal coating method. The calcined powders (800 °C) were sintered conventionally at three different temperatures (1050 °C, 1100 °C and 1150 °C) and the effect of sintering temperature on density, microstructure, composition and electrical properties was investigated. All the samples showed a single phase perovskite structure with orthorhombic symmetry similar to KNbO3 ceramics. Microstructure examined under FEG-SEM revealed an optimum microstructure, in terms of grain size, porosity and uniformity, at the sintering temperature of 1100 °C, which also showed density of 92% of ?Th. As the sintering temperature increased the X-ray diffraction peaks shifted to lower 2? values indicating excess volatilization of Na at higher temperature as compared to K. This was further confirmed through elemental Probe X-ray microanalysis and ICP-AES studies. Dielectric constant (?r), dielectric loss (tan?), ferroelectric (P-E loop) and piezoelectric (d33) properties showed considerable improvement and leakage current decreased with increasing sintering temperature. The sample sintered at 1100 °C showed marked improvement in maximum dielectric constant (573) at RT at 1 kHz, minimum tangent loss (0.04) at RT at 1 kHz, maximum remnant polarization (13.5 ?C/cm2), lower leakage current (7.6×10-7 A/cm2) and maximum d33 value (100 pC/N).

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

2014-02-01

425

Piezoelectric cantilever sensors  

NASA Technical Reports Server (NTRS)

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

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

2008-01-01

426

High-sensitivity piezoelectric perovskites for magnetoelectric composites  

NASA Astrophysics Data System (ADS)

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 BiScO3–PbTiO3 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.

Amorín, Harvey; Algueró, Miguel; Del Campo, Rubén; Vila, Eladio; Ramos, Pablo; Dollé, Mickael; Romaguera-Barcelay, Yonny; Pérez De La Cruz, Javier; Castro, Alicia

2015-02-01

427

Theory of ferroelectric polymer-ceramic composites  

Microsoft Academic Search

A model is proposed to establish the relevant constitutional parameters of ferroelectric composite materials such as shape, composition, and connectivity which determine the piezoelectric, dielectric, and elastic properties of the composite. A proper Monte Carlo method is used to calculate the active volumetric fraction of ceramic. An equivalent circuit is proposed to calculate the effective dielectric constant. The effective medium

Habtamu Zewdie; F. Brouers

1990-01-01

428

Piezoelectric composite materials  

NASA Technical Reports Server (NTRS)

A laminated structural devices has the ability to change shape, position and resonant frequency without using discrete motive components. The laminate may be a combination of layers of a piezoelectrically active, nonconductive matrix material. A power source selectively places various levels of charge in electrically conductive filaments imbedded in the respective layers to produce various configurations in a predetermined manner. The layers may be electrically conductive having imbedded piezoelectrically active filaments. A combination of layers of electrically conductive material may be laminated to layers of piezoelectrically active material.

Kiraly, L. J. (inventor)

1983-01-01

429

Adaptive piezoelectric sensoriactuator  

NASA Technical Reports Server (NTRS)

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

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

1996-01-01

430

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

NASA Astrophysics Data System (ADS)

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.

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

2014-04-01

431

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

SciTech Connect

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.

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

432

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

NASA Technical Reports Server (NTRS)

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

Kessel, Kurt

2011-01-01

433

Numerical solution of polarization saturation\\/dielectric breakdown model in 2D finite piezoelectric media  

Microsoft Academic Search

The polarization saturation (PS) model [Gao, H., Barnett, D.M., 1996. An invariance property of local energy release rates in a strip saturation model of piezoelectric fracture. Int. J. Fract. 79, R25–R29; Gao, H., Zhang, T.Y., Tong, P., 1997. Local and global energy release rates for an electrically yielded crack in a piezoelectric ceramic. J. Mech. Phys. Solids 45, 491–510], and

Cui-Ying Fan; Ming-Hao Zhao; You-He Zhou

2009-01-01

434

Design of a Circular Piezoelectric Transformer with Crescent-Shaped Input Electrodes  

Microsoft Academic Search

In this study, a new disk-type piezoelectric transformer design is proposed. The input side of the transformer has a crescent-shaped electrode and the output side has a focused poling direction. The electrodes and poling directions on commercially available piezoelectric ceramic disks were designed so that the planar or shear mode coupling factor (kp or k15) becomes effective rather than the

Burhanettin Koc; Yongkang Gao; Kenji Uchino

2003-01-01

435

Recent advances of conductive adhesives as a lead-free alternative in electronic packaging: Materials, processing, reliability and applications  

Microsoft Academic Search

Tin–lead solder alloys are widely used in the electronic industry. They serve as interconnects that provide the conductive path required to achieve connection from one circuit element to another. There are increasing concerns with the use of tin–lead alloy solders in recognition of hazards of using lead. Lead-free solders and electrically conductive adhesives (ECAs) have been considered as the most

Yi Li; C. P. Wong

2006-01-01

436

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

Microsoft Academic Search

Enhanced performance goals and environmental restrictions have heightened the consideration for use of alternative solders as replacements for the traditional tin-lead (Sn-Pb) eutectic and near-eutectic alloys. However, the implementation of non-Pb bearing surface finishes may lag behind solder alloy development. A study was performed which examined the effect(s) of Pb contamination on the performance of Sn-Ag-Bi and Sn-Ag-Cu-Sb lead-free solders

Paul Vianco; Jerry Rejent; I. Artaki; U. Ray; D. Finley; A. Jackson

1996-01-01

437

Novel flip-chip bonding technology for W-band interconnections using alternate lead-free solder bumps  

Microsoft Academic Search

A novel lead-free flip-chip technology for mounting high-speed compound semiconductor ICs, which have a relatively severe limitation regarding high-heat treatment, is presented. Solder bump interconnections of 0.95Sn-0.05Au were successfully fabricated by reflowing multilayer metal film at as low a temperature as 220°C. The bumps were designed to have a diameter of 36 ?m with a gap between the chip and

Kiyomitsu Onodera; Takao Ishii; Shinji Aoyama; Suehiro Sugitani; Masami Tokumitsu

2002-01-01

438

Assessing public exposure to silver-contaminated groundwater from lead-free solder: an upper bound, risk-based approach  

Microsoft Academic Search

The paper summarizes the results of a study to assess the potential human health risk associated with exposure to silver-contaminated groundwater from lead-free solder leachate. The specific alloy investigated is 96.3Sn\\/3.2Ag\\/0.7Cu. Silver transport in the groundwater is modeled using a one-dimensional advection-dispersion equation, and worst-case values for all system parameters have been chosen to provide a preliminary upper bound on

Eric R. Masanet

2002-01-01

439

Laser soldering of Sn-Ag-Cu and Sn-Zn-Bi lead-free solder pastes  

Microsoft Academic Search

It has reported that a waste of an electronics substrate including lead and its compound such as 63Sn-37Pb has polluted the environment with acid rain. For that environment problem the development of lead-free solder alloys has been promoted in order to find out the substitute for Sn-Pb solders in the United States, Europe, and Japan. In a present electronics industry,

Junichi Takahashi; Sumio Nakahara; Shigeyoshi Hisada; Takeyoshi Fujita

2004-01-01

440

Piezoelectric Polymer Shock Gauges  

NASA Astrophysics Data System (ADS)

The science and technology of piezoelectric materials has long been dominated by the availability of specific materials with particular properties. Piezoelectric PVDF (Poly(vinylidene fluoride) polymer and copolymers of PVDF with trifluoroethylene have shown to have the potential for new shock-wave sensors. Since 1981 through 1995, the piezoelectric response of PVDF was studied in a cooperative effort with François Bauer of ISL, France, R.A. Graham of Sandia National Laboratories and L.M. Lee of Ktech Corporation, Albuquerque. Among the known piezoelectric polymers, the PVDF plays an important role in measuring mechanical and physical state of matter under shock loading. The present paper presents the history of the development of the PVDF gauge. After 24 years of research in this area, main relevant results and data obtained are summarized as well as some original applications of the PVDF gauges.

Bauer, F.

2006-07-01

441

Piezoelectric Polymer Shock Gauges  

NASA Astrophysics Data System (ADS)

The science and technology of piezoelectric materials has long been dominated by the availability of specific materials with particular properties. Piezoelectric PVDF (Poly(vinylidene fluoride)) polymer and copolymers of PVDF with trifluoroethylene have shown that they have the potential for new shock-wave sensors. Since 1981 and until 1995, the piezoelectric response of PVDF has been studied in a cooperative effort with Francois Bauer of ISL, France, R.A. Graham of Sandia National Laboratories and L.M. Lee of the Ktech Corporation of Albuquerque. Among the known piezoelectric polymers, the PVDF plays an important role in measuring mechanical and physical state of matter under shock loading. The present paper presents the history of the development of the PVDF shock gauge. After 24 years of research in this area, main relevant results and data obtained are summarized as well as some of original applications of the PVDF gauges.

Bauer, François

2005-07-01

442

Microstructure basis for strong piezoelectricity in Pb-free Ba(Zr0.2Ti0.8)O3-(Ba0.7Ca0.3)TiO3 ceramics  

Microsoft Academic Search

In this letter, we use transmission electron microscopy to study the microstructure feature of recently reported Pb-free piezoceramic Ba(Zr0.2Ti0.8)O3-x(Ba0.7Ca0.3)TiO3 across its piezoelectricity-optimal morphotropic phase boundary (MPB) by varying composition and temperature, respectively. The domain structure evolutions during such processes show that in MPB regime, the domains become miniaturized down to nanometer size with a domain hierarchy, which coincides with the

Jinghui Gao; Dezhen Xue; Yu Wang; Dong Wang; Lixue Zhang; Haijun Wu; Shengwu Guo; Huixin Bao; Chao Zhou; Wenfeng Liu; Sen Hou; Ge Xiao; Xiaobing Ren

2011-01-01

443

Dielectric and piezoelectric properties of PbMg1\\/3Nb2\\/3O3-PbTiO3-PbZn1\\/3Nb2\\/3O3 ceramics  

Microsoft Academic Search

Dielectric and piezoelectric properties of (0.6-y) PbMg1\\/3Nb2\\/3O3-y PbZn1\\/3Nb2\\/3O3-0.4 PbTi03 are investigated. An initial lead oxide, magnesium or zinc oxide excess allowed pyrochlore free and densified samples to be obtained except for high substitution rate y. High remanent polarization and coercitive field are observed for y = 0 whatever the excess, and for y = 0.4 with magnesium and zinc oxides

F. Bossler; P. Escure; M. Lejeune; J. P. Mercurio

1993-01-01

444

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

NASA Astrophysics Data System (ADS)

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.

Mostofizadeh, Milad; Pippola, Juha; Frisk, Laura

2014-05-01

445

Laminated piezoelectric transformer  

NASA Technical Reports Server (NTRS)

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.

Vazquez Carazo, Alfredo (Inventor)

2006-01-01

446

Piezoelectric direct drive servovalve  

Microsoft Academic Search

A single-stage servovalve using direct piezoelectric actuator drive is described. The single-stage servovalve design offers higher bandwidth than conventional two-stage valves. It takes advantage of the high energy density in piezoelectric materials while addressing the need for internal amplification of stroke. When used alone, the valve can regulate pressure, and when used in combination with a hydraulic output device it

Jason E. Lindler; Eric H. Anderson

2002-01-01

447

Piezoelectrically Enhanced Photocathodes  

NASA Technical Reports Server (NTRS)

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

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

2011-01-01

448

Piezoelectric Energy Harvesting Solutions  

PubMed Central

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

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

2014-01-01

449

Model based analysis of piezoelectric transformers.  

PubMed

Piezoelectric transformers are increasingly getting popular in the electrical devices owing to several advantages such as small size, high efficiency, no electromagnetic noise and non-flammable. In addition to the conventional applications such as ballast for back light inverter in notebook computers, camera flash, and fuel ignition several new applications have emerged such as AC/DC converter, battery charger and automobile lighting. These new applications demand high power density and wide range of voltage gain. Currently, the transformer power density is limited to 40 W/cm(3) obtained at low voltage gain. The purpose of this study was to investigate a transformer design that has the potential of providing higher power density and wider range of voltage gain. The new transformer design utilizes radial mode both at the input and output port and has the unidirectional polarization in the ceramics. This design was found to provide 30 W power with an efficiency of 98% and 30 degrees C temperature rise from the room temperature. An electro-mechanical equivalent circuit model was developed to describe the characteristics of the piezoelectric transformer. The model was found to successfully predict the characteristics of the transformer. Excellent matching was found between the computed and experimental results. The results of this study will allow to deterministically design unipoled piezoelectric transformers with specified performance. It is expected that in near future the unipoled transformer will gain significant importance in various electrical components. PMID:16808951

Hemsel, T; Priya, S

2006-12-22

450

Molten-Salt Synthesis of Bismuth Titanate and Fabrication of PbTiO3-based Textured Ceramics  

Microsoft Academic Search

Grain-oriented ceramics, in which the grains are aligned around a preferred crystallographic axis, are of interest for increasing the figure of merit of piezoelectric ceramics. Templated grain growth (TGG), in which a fine matrix is recrystallised upon oriented seed crystals, is one of the more successful techniques for preparing ceramics with such crystallographic texture. Seeds are usually required to exhibit

Jingyan He; T. P. Comyn; T. Skidmore; S. J. Milne; A. J. Bell

2006-01-01

451

Optimum shape control of flexible beams by piezo-electric actuators  

NASA Technical Reports Server (NTRS)

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

Baz, A.; Poh, S.

1987-01-01