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1

Lead-free piezoelectric ceramics and thin films.  

PubMed

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

Safari, Ahmad; Abazari, Maryam

2010-10-01

2

Domain evolution in lead-free thin film piezoelectric ceramics  

NASA Astrophysics Data System (ADS)

Due to environmental and health concerns lead-free piezoelectric systems are currently being evaluated for use as replacements for lead-based ceramics. (1-x)Na0.5Bi0.5TiO3 - xBaTiO3 (NBT-xBT) is a promising alternative. In order to develop materials with improved performance, it is necessary to understand local structure effects on the piezoelectric response at the grain level. Using piezoresponse force microscopy (PFM), we have studied the domain evolution under locally applied electric fields. Using pulsed laser deposition thin films are deposited on Pt/Ti/SiO2/Si substrates at a temperature of 650 C in a 150 mTorr O2 environment. In NBT-0.05BT films, domains are clearly visible after the application of a bias field and they relax after a period of time. After the films are exposed to ambient conditions for several weeks, they must be annealed before domains are again visible with PFM. Domain images after poling indicate that the polarization direction is rotating in the plane of the sample.

Rogers, Meredith E.; Fancher, Chris M.; Blendell, John E.

2012-09-01

3

Domain evolution in lead-free thin film piezoelectric ceramics  

NASA Astrophysics Data System (ADS)

Due to environmental and health concerns lead-free piezoelectric systems are currently being evaluated for use as replacements for lead-based ceramics. Sodium Bismuth Titanate, Na0.5Bi0.5TiO 3 (NBT) - based materials offer possible alternatives. NBT is a perovskite-type, ABO3, compound and is ferroelectric at room temperature. It has a relatively high Curie temperature, a large remnant polarization, and a high coercive field at room temperature. NBT can be modified by additives, such as BaTiO3 (BT), to improve its properties further. NBT-xBT was originally reported to have a morphotropic phase boundary which lies at x = 0.06. The structure transforms from rhombohedral for x < 0.06 to tetragonal for x > 0.06. However, recent studies have shown that for some compositions NBT-xBT develop a relaxor phase at room temperature. NBT xBT materials in the compositional range between 0.05 ? x ? 0.11have been shown to contain nanodomains embedded in a non-polar cubic matrix. The fluctuations of these nanodomains give rise to the relaxor behavior which in some cases is referred to as "relaxor antiferroelectric". In contrast to ferroelectric materials, in relaxor ferroelectrics thermal fluctuations can cause the poled nanodomains to relax to an unpoled state. It is necessary to understand local structure effects on the piezoelectric response at the grain level in order to develop materials with improved performance. Using Piezoresponse Force Microscopy (PFM), this study examines the domain motion within individual grains and domain evolution over time under locally applied electric fields as well as single-point hysteresis loop measurements in thin film NBT and NBT-xBT. These experiments provide an understanding of the domain behavior that cannot be acquired through bulk, macroscopic measurements. Thin films are fabricated using hydrothermal deposition and pulsed laser deposition. The films are highly oriented and exhibit relaxor behavior at room temperature.

Dubelman, Meredith Elissa

4

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

NASA Astrophysics Data System (ADS)

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

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

2013-05-01

5

Lead-free KNLNT Piezoelectric Ceramics for High-frequency Ultrasonic Transducer Application  

PubMed Central

This paper presents the latest development of a lead-free piezoelectric ceramic and its application to transducers suitable for high-frequency ultrasonic imaging. A lead-free piezoelectric ceramic with formula of (K0.5Na0.5)0.97Li0.03(Nb0.9 Ta0.1)O3 (abbreviated as KNLNT-0.03/0.10) was fabricated and characterized. The material was found to have a clamped dielectric constant ?33S = ?0 = 890, piezoelectric coefficient d33 = 245 pC/N, electromechanical coupling factor kt = 0.42 and Curie temperature Tc > 300 C. High-frequency (40 MHz) ultrasound transducers were successfully fabricated with the lead-free material. A representative lead-free transducer had a bandwidth of 45%, two-way insertion loss of ?18 dB. This performance is comparable to reported performances of popular lead-based transducers. The comparison results suggest that the lead-free piezoelectric material may serve as an alternative to lead-based piezoelectric materials for high-frequency ultrasonic transducer applications.

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

2010-01-01

6

Study of BNT-BKT-BT lead-free piezoelectric ceramics and their application in piezoelectric devices  

Microsoft Academic Search

Lead-free piezoelectric ceramics, 0.90Bi0.5Na 0.5TiO3-0.05Bi0.5K0.5TiO3-0.05BaTiO 3 (BNKBT-5), have been fabricated by a solid-state reaction method. The dielectric, piezoelectric and ferroelectric properties of the ceramics have been measured and the microstructures studied by X-ray diffraction and SEM. In the ferroelectric hysteresis loop measurements, Pr 28.5 muC\\/cm2 and Ec 3.5 MV\\/m have been observed. The electromechanical coupling coefficients kp and kt

Siu Hong Choy

2007-01-01

7

Microstructures and Piezoelectric Properties of Knnlst Doping Bczt Lead-Free Ceramics  

NASA Astrophysics Data System (ADS)

In this study, lead-free piezoelectric ceramics (Na0.52K0.44Li0.04)(Nb0.88Sb0.08Ta0.04)O3-doped 0.52Ba(Zr0.2Ti0.8)O3-0.48(Ba0.7Ca0.3)TiO3(BCZT-xKNNLST) are investigated. The effects of the KNNLST addition on the microstructures and the electrical properties of the ceramics sintered at the temperature as low as 1350C are studied. The X-ray diffraction data show that the addition of KNNLST could diffuse into BCZT lattice and a pure perovskite phase is formed. With the increase of KNNLST addition, the average grain size is first increased and afterwards decreased. The ceramics with x = 0.005 exhibit a good piezoelectric behavior of d33 464 pC/N and kp 0.44 after three month's aging, which indicates the BCZT-xKNNLST ceramics could be promising for lead-free practical applications.

Xu, Wei; Li, Yang; Feng, Jian-Min; Dai, Ye-Jing

2012-12-01

8

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

9

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

10

Study of BNT-BKT-BT lead-free piezoelectric ceramics and their application in piezoelectric devices  

NASA Astrophysics Data System (ADS)

Lead-free piezoelectric ceramics, 0.90Bi0.5Na 0.5TiO3-0.05Bi0.5K0.5TiO3-0.05BaTiO 3 (BNKBT-5), have been fabricated by a solid-state reaction method. The dielectric, piezoelectric and ferroelectric properties of the ceramics have been measured and the microstructures studied by X-ray diffraction and SEM. In the ferroelectric hysteresis loop measurements, Pr 28.5 muC/cm2 and Ec 3.5 MV/m have been observed. The electromechanical coupling coefficients kp and kt are 0.31 and 0.46, respectively. Those properties are comparable to that of lead-based ceramics such as PZT. Three different compounds, including CeO2, Ca2Fe 2O5 and (Bi0.5Li0.5)TiO3, have been used as additives/dopants to improve the properties of BNKBT-5. All the samples with different compositions have been characterized. The measured properties are compared with that of BNKBT-5. It has been found that the BNKBT-5 doped with 1.5 mol% of (Bi0.5Li0.5)TiO3, namely BNKLBT-1.5, has the best performance. It can enhance kp, kt, Qm, Pr, and can reduce tandelta but do not lower the depolarization temperature. Two different types of devices have been fabricated using BNKBT-5 and BNKLBT-1.5 ceramic rings. The first device is compressive-type accelerometers. A PZT accelerometer with similar structure has also been fabricated for comparison. The accelerometers are calibrated using a back-to-back calibration method against a standard reference accelerometer. Within the +/-2.5% tolerance, the mean sensitivity of PZT, BNKBT and BNKLBT accelerometer is 4.34 pC/ms -2 (50 Hz to 8.24 kHz), 2.24 pC/ms-2 (50 Hz to 10.1 kHz) and 2.97 pC/ms-2 (50 Hz to 12.45 kHz), respectively. The BNKLBT-1.5 accelerometer has a reasonably high sensitivity and the broadest sensing frequency range which would be the most preferable choice for structural health monitoring applications. The second device is ultrasonic wirebonding transducers for microelectronic packaging. It has been found that if titanium is used as the metal parts in the transducer, the BNKLBT-1.5 transducer has similar axial displacement (1.6 mum) to that of PZT/stainless steel (state-of-the-art transducer) transducer presumably because the lead-free ceramic has an acoustic impedance close to that of titanium metal. The lateral displacement of the BNKLBT-1.5 is much smaller than that of PZT transducer thus can improve the bonding quality. It shows that lead-free ceramics has the potential to replace PZT in certain transducer designs.

Choy, Siu Hong

11

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

NASA Astrophysics Data System (ADS)

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

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

2013-10-01

12

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

13

(Bi(1/2)Na(1/2))TiO3-BaTiO3 system for lead-free piezoelectric ceramics  

NASA Astrophysics Data System (ADS)

One of the (Bi(1/2)Na(1/2))TiO3 (BNT)-based solid solutions, Ba-modified bismuth sodium titanate, (Bi(1/2)Na(1/2))(1-x)Ba(x)TiO3 (BNBT), is studied for its dielectric and piezoelectric properties as a new group of lead-free piezoelectric ceramics. A rhombohedral (F sub alpha)-tetragonal (F sub beta) morphotropic phase boundary (MPB) is shown to exist at x = 0.06-0.07 by X-ray data, and dielectric and piezoelectric properties. BNBT ceramics with the MPB composition are superior as piezoelectric ceramics in high-frequency ultrasonic applications or as piezoelectric actuator materials because of a lower free permittivity, and a high electromechanical coupling factor, along with high mechanical strength.

Takenaka, Tadashi; Maruyama, Kei-Ichi; Sakata, Koichiro

1991-09-01

14

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

PubMed

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

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

2014-02-01

15

Piezoelectric properties of (Li, Ag) modified (Na 0.50K 0.50)NbO 3 lead-free ceramics with high Curie temperature  

Microsoft Academic Search

Lead-free piezoelectric ceramics (1?x)[(Na0.4725K0.4725)Li0.055]NbO3x(Ag0.5Li0.5)NbO3 [(1?x)KNNLxALN] have been prepared by the conventional mixed oxide method. The ceramics show good piezoelectric and ferroelectric properties. Effect of the amount of (Ag0.5Li0.5)NbO3 (ALN) on the phase structure, microstructure, piezoelectric and ferroelectric properties of (1?x)KNNLxALN ceramics were systematically investigated. It is found that the samples with 1mol% ALN exhibit good piezoelectric and ferroelectric properties, and

Yuanyu Wang; Jiagang Wu; Dingquan Xiao; Jianguo Zhu; Ping Yu; Lang Wu; Xiang Li

2008-01-01

16

Structure and electrical properties of K{sub 0.5}Na{sub 0.5}NbO-LiSbO lead-free piezoelectric ceramics  

Microsoft Academic Search

Lead-free piezoelectric ceramics (1-x)K{sub 0.5}Na{sub 0.5}NbO-xLiSbO have been fabricated by a conventional ceramic sintering technique. The results of x-ray diffraction suggest that Li{sup +} and Sb{sup 5+} diffuse into the K{sub 0.5}Na{sub 0.5}NbO lattices to form a solid solution with a perovskite structure. The ceramics can be well sintered at 1070-1110 degree sign C. The introduction of LiSbO into the

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

2007-01-01

17

Development of lead-free (Bi 1/2 Na 1/2)BaTiO3 piezoelectric ceramics for clinical applications.  

PubMed

The present paper provides a method for the manufacture of lead-free piezoelectric ceramics, based on Bismuth-Sodium Titanate (Bi 1/2 Na 1/2)BaTiO3 commonly abbreviated as BNBT. Also, this paper shows the characterization of this piezoceramics, like the Curie temperature, the dielectric constant, resonant frequency, etc. This piezoceramics can be used in medical application where a high frequency transducer is needed as well as ultrasound. PMID:18002432

Rodrguez-Ruiz, R; Suaste-Gmez, E

2007-01-01

18

High piezoelectric d33 coefficient in Li-modified lead-free (Na,K)NbO3 ceramics sintered at optimal temperature  

NASA Astrophysics Data System (ADS)

LiNbO3-doped (Na,K)NbO3 lead-free piezoelectric ceramics were prepared by normal sintering, and the electrical properties were investigated with a special emphasis on the influence of sintering temperature. The ceramics synthesized at 1020-1080 C showed a phase transition from orthorhombic to tetragonal symmetry, which is similar to the morphtropic phase boundary (MPB). Because of such MPB-like behavior, a high piezoelectric coefficient d33 (314 pC/N) was obtained in the nominal composition 0.058LiNbO3-0.942[(Na0.535K0.480)NbO3] ceramic sintered at 1060 C however, this high d33 value was reported previously only in the Li-modified (Na,K)NbO3-based ceramics with codopants of Ta and Sb to B site.

Zhao, Pei; Zhang, Bo-Ping; Li, Jing-Feng

2007-06-01

19

Fabrication of Lead-Free Piezoelectric KNbO3 Ceramics by Modified Solid State Reaction Method  

NASA Astrophysics Data System (ADS)

Potassium niobate (KNbO3) fine powder has been successfully synthesized at a low temperature of 500 C through a modified solid state reaction, in which urea [CO(NH2)2] plays an important role. High-density KNbO3 ceramics can be obtained by the conventional sintering of the synthesized KNbO3 fine powder with the addition of 1 mol % Co3O4, which is a sintering additive. Their crystal structure, microstructure, and dielectric and piezoelectric properties were characterized. The KNbO3 ceramics show a comparatively saturated P-E hysteresis loop. The remnant polarization and coercive field are 14 ?C/cm2 and 16 kV/cm, respectively. The KNbO3 ceramics also show piezoelectricity with a planar electromechanical coupling factor, kp, of 16%.

Wada, Takahiro; Suzuki, Akito; Saito, Takehisa

2006-09-01

20

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

PubMed Central

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

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

2009-01-01

21

Grain-oriented sodium bismuth titanate-based lead-free piezoelectric ceramics prepared using the pulsed strong magnetic field and template grain growth  

NASA Astrophysics Data System (ADS)

In this paper, 0.94Bi0.5Na0.5TiO3-0.06BaTiO3 (BNBT6) lead-free piezoelectric ceramics have been prepared using the gelcasting technology. The dielectric and piezoelectric properties of these ceramics have been investigated. The specimens were sintered at 1100-1200 C after grain-oriented under the pulsed strong magnetic field during the solidification of the green bodies. Compared with the BNBT6 samples without applying magnetic field, the ceramics textured by applying 5 T pulsed magnetic field has a coercive field with reduction of 400 V/mm, which makes the polarization process easier. Meanwhile, it is noted that the orientation degree increases with increasing sintering temperature, whereas the piezoelectric constant and electromechanical coupling coefficients are improved. If SrTiO3 seed grain is introduced, the orientation degree can reach 0.70 and the relative density of the sintered ceramics is up to 96%. The dielectric properties are anisotropic in directions vertical and parallel to the applied magnetic field. At around 180 C, the dielectric constant in the direction vertical to the magnetic field is three times of that in the direction parallel to the magnetic field. And the dielectric loss in the direction vertical to the magnetic field is also higher than that in the direction parallel to the magnetic field.

Zhao, Jun; Wang, Fajun; Li, Wen; Li, Hui; Zhou, Dongxiang; Gong, Shuping; Hu, Yunxiang; Fu, Qiuyun

2010-10-01

22

Polymorphic structure evolution and large piezoelectric response of lead-free (Ba,Ca)(Zr,Ti)O3 ceramics  

NASA Astrophysics Data System (ADS)

The polymorphic structure evolution of (Ba,Ca)(Zr,Ti)O3 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 (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 composition. The electric properties near the O-T phase boundaries of (Ba0.95Ca0.05)(Zr0.05Ti0.95)O3 and (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 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; Chao, Xiaolian; Jin, Li; Wei, Lingling; Liang, Pengfei; Yang, Zupei

2014-03-01

23

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

NASA Astrophysics Data System (ADS)

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

Nagata, Hajime; Takenaka, Tadashi

1998-09-01

24

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

NASA Astrophysics Data System (ADS)

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

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

2012-04-01

25

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

26

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  

NASA Astrophysics Data System (ADS)

A lead-free piezoelectric ceramic ternary system based on bismuth sodium titanate, (Bi1/2Na1/2)TiO3 (BNT) - bismuth potassium titanate (Bi1/2K1/2)TiO3 (BKT) - barium titanate BaTiO3 (BT) near the morphotropic phase boundary (MPB) between the tetragonal and rhombohedral phases has been investigated. In the case of a(Bi1/2Na1/2)TiO3-bBaTiO3-c(Bi1/2K1/2)TiO3 [BNBK(100a/100b/100c)] solid solution ceramics, the highest piezoelectric constant d33=191 pC/N, Curie temperature, Tc=301C, electromechanical coupling factor, k33=0.56 and dielectric constant, {\\varepsilon33}T/\\varepsilon0=1141 are observed for the BNBK(85.2/2.8/12) composition which has a tetragonal phase near the MPB. The d33 value is the highest so far reported for all lead-free piezoelectric ceramics with Tc>300C. The BNT-BKT-BT ternary ceramics system sintered at 1200C for 2 h in air has a pure perovskite structure and a high density more than 95% of the theoretical density.

Nagata, Hajime; Yoshida, Masaki; Makiuchi, Yoichi; Takenaka, Tadashi

2003-12-01

27

Preparation and piezoelectric properties of CeO2-added (Na0.475K0.475Li0.05) (Nb0.92Ta0.05Sb0.03)O3 lead-free ceramics  

NASA Astrophysics Data System (ADS)

Lead-free piezoelectric ceramics (Na0.475K0.475Li0.05)(Nb0.92Ta0.05Sb0.03)O3 containing different amounts of CeO2 have been prepared by a conventional mixed-oxide method. After the addition of CeO2, the sintering performance of the ceramics is improved. The ceramics can be well sintered at a higher temperature. The ceramics become dense and have better dielectric and piezoelectric properties. For the ceramic added with 0.4 wt% CeO2, the piezoelectric and dielectric properties become optimum, giving a piezoelectric coefficient of 246 pC N-1 and a planar-mode electromechanical coupling coefficient of 0.50.

Lee, Tact; Kwok, K. W.; Chan, H. L. W.

2008-08-01

28

Linking large piezoelectric coefficients to highly flexible polarization of lead free BaTiO3-CaTiO3-BaZrO3 ceramics  

NASA Astrophysics Data System (ADS)

We report a large d31 piezoelectric coefficient and corresponding electromechanical coupling factor, Kp, of 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 (BCTZ50) and 0.68Ba(Zr0.2Ti0.8)O3-0.32(Ba0.7Ca0.3)TiO3 (BCTZ32) lead-free piezoceramics. The piezoelectric coefficient, d31, reaches a high value of 200 pC/N for BCTZ50 at room temperature which is comparable to the one of the soft PZT. This confirms the previously reported d33 for the same material. A useful way to achieve such performances at the expense of a smaller thermal budget is suggested, enabling better control of the ceramics composition and microstructure. Based on pyroelectric and ferroelectric hysteresis loops measurements, we show that such outstanding properties are likely due to the high flexibility of polarization under thermal and electric stresses.

Benabdallah, F.; Simon, A.; Khemakhem, H.; Elissalde, C.; Maglione, M.

2011-06-01

29

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=301C, electromechanical coupling factor,

Hajime Nagata; Masaki Yoshida; Yoichi Makiuchi; Tadashi Takenaka

2003-01-01

30

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

NASA Astrophysics Data System (ADS)

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

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

2005-04-01

31

Piezoelectric, ferroelectric and dielectric properties of Sm 2O 3-doped (Bi 0.5Na 0.5) 0.94Ba 0.06TiO 3 lead-free ceramics  

Microsoft Academic Search

Sm2O3 (00.7wt.%)-doped (Bi0.5Na0.5)0.94Ba0.06TiO3 (abbreviated as BNBT6) lead-free piezoelectric ceramics were synthesized by conventional solid-state processes. The effects of Sm2O3 on the microstructure, dielectric properties and piezoelectric properties were investigated. X-ray diffraction (XRD) patterns show that 0.10.7wt.% of Sm2O3 can diffuse into the lattice of BNBT6 ceramics forming pure perovskite phase. The SEM images indicate that the microstructure can be affected

Peng Fu; Zhijun Xu; Ruiqing Chu; Wei Li; Guozhong Zang; Jigong Hao

2010-01-01

32

Lead-free piezoelectric ceramics of (Bi1\\/2Na1\\/2)TiO3-BaTiO3-BiFeO3 system  

Microsoft Academic Search

Bismuth sodium titanate, (Bi1\\/2Na1\\/2)TiO3 (BNT)-based solid solution, a(Bi1\\/2Nal\\/2)TiO3-bBaTiO3-cBiFeO3, [BNBTF(100a\\/100b\\/100c)], was studied for its dielectric, ferroelectric and piezoelectric properties, as a new group of lead-free piezoelectric ceramics. Curie temperatures, Tc. of the BNBTF ceramics shift to the higher temperature with an increasing amount of modified Bi ion, and temperature dependence of the resonance frequencies, fr is smaller with increasing amount of

Hajime Nagata; Nobuhiro Koizumi; Nobuhisa Kuroda; Isao Igarashi; Tadashi Takenaka

1999-01-01

33

Effect of Dy 2O 3 on the structure and electrical properties of (Bi 0.5Na 0.5) 0.94Ba 0.06TiO 3 lead-free piezoelectric ceramics  

Microsoft Academic Search

Dy2O3 (00.8wt.%)-doped (Bi0.5Na0.5)0.94Ba0.06TiO3 (abbreviated as BNBT6) lead-free piezoelectric ceramics were synthesized by conventional solid-state processes. The compositional dependence of phase structure and electrical properties of the ceramics was studied. X-ray diffraction (XRD) data shows that 0.20.8wt.% Dy2O3 can diffuse into the lattice of BNBT6 ceramics and forms a pure perovskite phase. SEM images indicate that all the modified ceramics have

Peng Fu; Zhijun Xu; Ruiqing Chu; Wei Li; Qian Xie; Yanjie Zhang; Qian Chen

2010-01-01

34

A generalized rule for large piezoelectric response in perovskite oxide ceramics and its application for design of lead-free compositions  

NASA Astrophysics Data System (ADS)

We present a general rule for the perovskite oxide ceramics: ``A large piezoelectric constant in ABO3 perovskite ceramics can be obtained by tuning the weight ratio of A and B sites, WA/WB or WB/WA, to 3. Piezoelectric constant decreases significantly when WA/WB or WB/WA is in the range of 0.5-2.0, termed as forbidden zone.'' A comparative analysis was conducted for broad range of materials demonstrating the applicability of proposed rule. Further based on this rule optimized compositions in BaTiO3 and alkali niobate based systems were developed. Polycrystalline ceramics in modified BaTiO3 system were found to exhibit longitudinal piezoelectric coefficient (d33) of 330 pC/N, while alkali niobate ceramics showed d33 of 294 pC/N.

Ahn, Cheol-Woo; Maurya, Deepam; Park, Chee-Sung; Nahm, Sahn; Priya, Shashank

2009-06-01

35

Phase Transition and Dielectric Properties of Lead Free (K0.5Na0.5)NbO3- Bi(Zn0.5Ti0.5)O3 Piezoelectric Ceramics  

Microsoft Academic Search

Lead-free piezoelectric ceramics of (1-x)(K0.5Na0.5)NbO3? x(Bi(Zn0.5Ti0.5)O3; x = 0.000.30 were prepared via the two?stage mixed oxide fabrication technique. The crystal structure and ferroelectric phase transitions were studied by means of x-ray diffraction and thermal measurements. XRD results showed that a single-phase perovskite structurewas formed in the ceramics with x ? 0.25. For the ceramics with x = 0.30, a small

Manoon Sutapun; Naratip Vittayakorn

2009-01-01

36

Lead-free ceramics for pyroelectric applications  

NASA Astrophysics Data System (ADS)

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

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

2008-05-01

37

Formation of Morphotropic Phase Boundary in (Na0.5K0.5)NbO3--BaZrO3--(Bi0.5Li0.5)TiO3 Lead-Free Piezoelectric Ceramics  

NASA Astrophysics Data System (ADS)

For the development of lead-free piezoelectric ceramics, which have a tetragonal--rhombohedral morphotropic phase boundary (MPB), 0.90(Na0.5K0.5)NbO3--xBaZrO3--(0.10 - x)(Bi0.5Li0.5)TiO3 ceramics have been synthesized by the conventional solid state reaction method. A phase diagram was summarized from the X-ray diffraction pattern and the dielectric measurements. It is found that 0.90(Na0.5K0.5)NbO3--xBaZrO3--(0.10 - x)(Bi0.5Li0.5)TiO3 ceramics have an MPB between x = 0.07 and 0.08. In the vicinity of the MPB, it was observed that the dielectric and piezoelectric properties were enhanced.

Zushi, Junta; Ariizumi, Takuma; Kojima, Seiji; Wang, Ruiping; Bando, Hiroshi

2013-07-01

38

High Power (Na0.5K0.5)NbO3Based Lead-Free Piezoelectric Transformer  

Microsoft Academic Search

Though there is a lot of research related with lead-free piezoelectric materials, high power characteristics of the candidate lead-free materials have not been looked into in the literature under equilibrium conditions. This paper reports high power characteristics of a sodium potassium niobate (NKN) based ceramic under equilibrium conditions, and its application as a candidate material for piezoelectric transformers compared with

Erkan A. Gurdal; Seyit O. Ural; Hwi-Yeol Park; Sahn Nahm; Kenji Uchino

2011-01-01

39

Phase transitional behavior and electrical properties of lead-free (K0.44Na0.52Li0.04)(Nb0.96-xTaxSb0.04)O3 piezoelectric ceramics  

NASA Astrophysics Data System (ADS)

Lead-free (K0.44Na0.52Li0.04)(Nb0.96-xTaxSb0.04)O3 piezoelectric ceramics have been synthesized by conventional solid state sintering process. Two morphotropic phase boundaries (MPBs) respectively corresponding to the orthorhombic to tetragonal and tetragonal to pseudocubic phases are observed with increasing x. The ceramics with x=0.20 between the two MPBs show significantly enhanced electrical properties, which are as follows: piezoelectric constant d33=252 pC/N, planar coupling coefficient kp=0.42, dielectric constant ?r=1503, and dielectric loss tan ?=0.025, and they show good stability. Lead-free superthin buzzer disks have been prepared by using piezoceramic membrane with x=0.20. (K0.44Na0.52Li0.04)(Nb0.96-xTaxSb0.04)O3 ceramics are very promising as lead-free replacements for lead zirconate titanate.

Yang, Zupei; Chang, Yunfei; Wei, Lingling

2007-01-01

40

Microstructure and piezoelectric properties of lead-free (1-x)(Na0.5K0.5)NbO3-xCaTiO3 ceramics  

NASA Astrophysics Data System (ADS)

The crystal structure of (1-x)(Na0.5K0.5)NbO3-xCaTiO3 ceramics began to change from orthorhombic to tetragonal at x>=0.03, then became a morphotropic phase boundary in which both the orthogonal and tetragonal phases coexisted at 0.03=0.07. The Curie temperature decreased with increasing x and the specimen became a relaxor at x>=0.03. A dense microstructure with large grains was developed at 0.04piezoelectric properties of the specimens. High piezoelectric properties of d33=241, kp=0.41, and ?3T/Vo=1316 were obtained from the 0.95NKN-0.05CT ceramics sintered at 1050 C for 2 h, indicating that the 0.95NKN-0.05 ceramic is a good candidate material for lead-free piezoelectric ceramics.

Park, Hwi-Yeol; Cho, Kyung-Hoon; Paik, Dong-Soo; Nahm, Sahn; Lee, Hyeung-Gyu; Kim, Duk-Hee

2007-12-01

41

Dielectric properties in lead-free piezoelectric (Bi0.5Na0.5)TiO3BaTiO3 single crystals and ceramics  

NASA Astrophysics Data System (ADS)

The 0.93(Bi0.5Na0.5)TiO30.07BaTiO3 (BNB7T) piezoelectric single crystals and ceramics have been grown respectively by using the self-flux and solid-state-reaction methods. The real (??) and imaginary (??) parts of the dielectric permittivity of BNB7T crystals and ceramics were investigated with and without an electric (E) poling as functions of temperature and frequency. The BNB7T crystal shows a stronger dielectric maximum at Tm~240 C than the ceramic at Tm~300 C. The dielectric permittivity of BNB7T ceramic shows an extra peak after poling at an electric field E=40 kV/cm in the region of 80100 C designated as the depolarization temperature (Td). A wide-range dielectric thermal hysteresis was observed in BNB7T crystal and ceramic, suggesting a first-order-like phase transition. The dielectric permittivity ?? obeys the CurieWeiss equation, ??=C/(T?To), above 500 C, which is considered as the Burns temperature (TB), below which polar nanoregions begin to develop and attenuate dielectric responses.

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

2014-05-01

42

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

NASA Astrophysics Data System (ADS)

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

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

2012-09-01

43

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

NASA Astrophysics Data System (ADS)

Lead-free piezoelectric compositions of the (1- x)Bi0.5(Na0.40K0.10)TiO3- x(Ba0.7Sr0.3)TiO3 system (when x = 0, 0.05, 0.10, 0.15, and 0.20) were fabricated using a solid-state mixed oxide method and sintered between 1,050C and 1,175C for 2 h. The effect of (Ba0.7Sr0.3)TiO3 [BST] content on phase, microstructure, and electrical properties was investigated. The optimum sintering temperature was 1,125C at which all compositions had densities of at least 98% of their theoretical values. X-ray diffraction patterns that showed tetragonality were increased with the increasing BST. Scanning electron micrographs showed a slight reduction of grain size when BST was added. The addition of BST was also found to improve the dielectric and piezoelectric properties of the BNKT ceramic. A large room-temperature dielectric constant, ? r (1,609), and piezoelectric coefficient, d 33 (214 pC/N), were obtained at an optimal composition of x = 0.10.

Jaita, Pharatree; Watcharapasorn, Anucha; Jiansirisomboon, Sukanda

2012-01-01

44

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

PubMed Central

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

2012-01-01

45

Microstructure and piezoelectric properties of the CuO-added (Na0.5K0.5)(Nb0.97Sb0.03)O3 lead-free piezoelectric ceramics  

NASA Astrophysics Data System (ADS)

The presence of the Sb5+ ion increased the piezoelectric properties of the (Na0.5K0.5)NbO3 (NKN) ceramics by enhancing the poling state as identified by the increased phase angle (?). The increased ? value was explained by the increased ferroelectricity due to the large electronegativity of the Sb5+ ion and the increased off centering of the cation due to the small ionic size of the Sb5+ ion. The (Na0.5K0.5)(Nb0.97Sb0.03)O3[NK(N0.97S0.03)] ceramics containing CuO were well sintered even at 960 C. A small amount of the Cu2+ ions was incorporated into the matrix of the NK(N0.97S0.03) ceramic and behaved as a hardener. The kp, Qm, d33, and ?3T/V0 values of the CuO-added NK(N0.97S0.03) ceramics were much higher than those of the CuO-added NKN ceramics due to the Sb5+ ion's enhancement of the piezoelectric properties by increasing the poling state of the specimens. The high piezoelectric properties of kp=0.41, Qm=1333, d33=111 pC/N, and V3T/V0=324 were obtained from the 2.0 mol % CuO-added NK(N0.97S0.03) ceramics sintered at 960 C for 8 h.

Park, Hwi-Yeol; Seo, In-Tae; Choi, Min-Kyu; Nahm, Sahn; Lee, Hyeung-Gyu; Kang, Hyung-Won; Choi, Byung-Hyun

2008-08-01

46

Performance of lead-free piezoelectric materials in cantilever-based energy harvesting devices  

NASA Astrophysics Data System (ADS)

Energy harvesting is one of the emerging applications of piezoelectric materials. In order to replace conventional lead-based materials with lead-free materials, it is important to evaluate their performance for such applications. In the present study, finite element method-based simulation shows mean power density produced from (K0.475Na0.475Li0.05)(Nb0.92Ta0.05Sb0.03)O3 add with 0.4 wt.% CeO2 and 0.4 wt.% MnO2 (KNLNTS) bimorph is 96.64% of lead zirconate titanate (Pb [ZrxTi1-x] O3) (PZT) ceramics. Load resistance (R), length of proof mass (Lm) and thickness of host layer (th) are optimized (using genetic algorithm) for maximum power density and tuning the operating frequency range which is near to natural frequency of the structure. The lead-free piezoelectric material KNLNTS has comparable results to that of PZT for piezoelectric energy harvester in the ambient frequency range of 90 Hz to 110 Hz. Results show that KNLNTS ceramics can be potentially used in energy harvesting devices.

Kumar, Anuruddh; Kumar, Rajeev; Chauhan, Vishal S.; Vaish, Rahul

2014-05-01

47

Raman- and Brillouin-scattering studies on lead-free piezoelectric Bi0.5(Na0.78K0.22)0.5- x TiO3 ceramics with A-site vacancies  

NASA Astrophysics Data System (ADS)

The Raman and Brillouin spectra of lead-free piezoelectric Bi0.5(Na0.78K0.22)0.5- x TiO3 ceramics with A-site vacancies were investigated for x = 0 0.05. The Raman spectra measured at room temperature showed seven broad bands over the range of 50-1000 cm-1, reflecting strong anharmonicity, inherent A-site disorder and the resulting breakdown of the Raman selection rule. The splitting of the A1 mode near 270 cm-1 indicated that the tetragonal symmetry was maintained over the whole x range, consistent with the X-ray diffraction results. The Brillouin spectra exhibited distributed longitudinal and transverse acoustic modes, in addition to central peaks. The distributed acoustic modes were attributed to the scattering events at all scattering angles from 0 to 180 due to multiple reflections and refractions at the grain boundaries. The relaxation time obtained from fitting the broad central peak by using a Debye function exhibited a slowing-down behavior in the paraelectric phase. The formation of the central peak was attributed to the existence of nano-sized polar regions due to the anharmonic vibrations and the hopping motions of the A-site cations.

Kim, Tae Hyun; Kojima, Seiji; Ahn, Chang Won; Kim, Ill Won; Ko, Jae-Hyeon

2013-04-01

48

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

NASA Astrophysics Data System (ADS)

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

Abazari Torghabeh, Maryam

49

Piezoelectric properties of lead-free submicron-structured (Bi0.5Na0.5)0.94Ba0.06TiO3 ceramics from nanopowders  

NASA Astrophysics Data System (ADS)

Submicron-structured (Bi0.5Na0.5)0.94Ba0.06TiO3 (BNBT6) ceramics were obtained from nanometric powder synthesized by sol-gel auto-combustion at 500 C. Hot-pressing at low temperatures and a combination of this with recrystallization, still moderate in order to reduce the loss of volatile elements, have been tested. Material properties, including all losses, were determined at the resonances of thin discs using Alemany et al software. Ceramics hot-pressed at 700-800 C for 2 h have a pseudo-cubic structure, a grain size of a few hundred nanometers and are homogeneous. Both their crystal structure and the lack of sintering prevent their poling. For ceramics hot-pressed at 950 C for 3 h, Bi or Bi0.5Na0.5 loss, together with low piezoelectric properties (d33 = 60 pC N - 1, kp = 8.3% and kt = 9.5%), was observed. Recrystallization at 1000 C-1 h of ceramics hot-pressed at 700 and 800 C for 2 h keeps the submicron structure, reduces porosity and prevents off-stoichiometry. Mechanical and piezoelectric losses are also reduced and coupling factors increased (kp = 24.6%, kt = 36.4%). The best piezoelectric coefficient obtained in these ceramics (d33 = 143 pC N - 1) is comparable with those reported for coarse-grained ceramics.

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

2010-11-01

50

Microstructure, dielectric, and piezoelectric properties of (Li, Ag, Ta) modified (K0.50Na0.50)NbO3 lead-free ceramics with high Curie temperature  

Microsoft Academic Search

(1-x)[(K0.4725Na0.4725Li0.055)NbO3]-xAgTaO3 [(1-x)KNNL-xAT] lead-free ceramics have been prepared by the conventional mixed oxide method. Effect of the AgTaO3 (AT) content on the microstructure and electrical properties of (1-x)KNNL-xAT ceramics were systematically investigated. A morphotropic phase boundary (MPB) between orthorhombic and tetragonal phases was identified in the composition range of 0.015

Yuanyu Wang; Jiagang Wu; Dingquan Xiao; Jumu Zhu; Yong Jin; Jianguo Zhu; Ping Yu; Lang Wu; Xiang Li

2007-01-01

51

Electromechanical properties and dielectric behavior of (Bi 1/2Na 1/2) (1-1.5 x) Bi xTiO 3 lead-free piezoelectric ceramics  

NASA Astrophysics Data System (ADS)

Bismuth doped bismuth sodium titanate ceramics [(Bi 1/2Na 1/2) (1-1.5 x) Bi xTiO 3, x=0 to 0.06] were prepared, and the resulting effects on the microstructure and dielectric properties were examined. All of the Bi-doped ceramics exhibited a single phase of perovskite structure with rhombohedral symmetry. The poling leakage current was significantly reduced by the doping of Bi, facilitating the poling process of the ceramics. The doping with Bi enhances the piezoelectric properties and increases the dielectric constant and the dielectric loss of the ceramics. At 2 mol% Bi-doping level, the ceramics exhibit a large remanent polarization of 47 ?C/cm 2 and a relatively low coercive field of 71 kV/cm, while their d 33 and kp reach a maximum value of 95 pC/N and 21%, respectively.

Wang, X. X.; Kwok, K. W.; Tang, X. G.; Chan, H. L. W.; Choy, C. L.

2004-02-01

52

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

PubMed

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

Aksel, Elena; Jones, Jacob L

2010-01-01

53

New potassium-sodium niobate material system: a giant-d33 and high-TC lead-free piezoelectric.  

PubMed

In this work, we elucidate the influence of Bi0.5Li0.5ZrO3 (BLZ) content on the phase structure, microstructure, and electrical properties of (1 -x)K0.40Na0.60Nb0.965Sb0.035O3-xBi0.5Li0.5ZrO3 lead-free ceramics. We simultaneously achieved a giant d33 and a high TC 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 TC. The ceramic with x = 0.03 shows an enhanced piezoelectric behaviour (d33? 400 pC N(-1) and kp? 0.47) together with a high TC 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-TC 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

54

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

NASA Astrophysics Data System (ADS)

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

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

2007-12-01

55

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

PubMed Central

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

2012-01-01

56

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

NASA Astrophysics Data System (ADS)

Lead-free 0.98(Na0.5K0.5)NbO3-0.02Ba(Zr0.52Ti0.48)O3 [0.98NKN-0.02BZT] ceramics were fabricated by the conventional mixed oxide method with sintering temperature at 1,080C to 1,120C. The results indicate that the sintering temperature obviously influences the structural and electrical properties of the sample. For the 0.98NKN-0.02BZT ceramics sintered at 1,080C to 1,120C, the bulk density increased with increasing sintering temperature and showed a maximum value at a sintering temperature of 1,090C. The dielectric constant, piezoelectric constant [ d 33], electromechanical coupling coefficient [ k p], and remnant polarization [ P r] increased with increasing sintering temperature, which might be related to the increase in the relative density. However, the samples would be deteriorated when they are sintered above the optimum temperature. High piezoelectric properties of d 33 = 217 pC/N, k p = 41%, dielectric constant = 1,951, and ferroelectric properties of P r = 10.3 ?C/cm2 were obtained for the 0.98NKN-0.02BZT ceramics sintered at 1,090C for 4 h.

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

2012-01-01

57

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

58

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

PubMed

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

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

2014-01-01

59

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

SciTech Connect

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

Tai, Cheuk W.; Lereah, Y. [Department of Physical Electronics, School of Electrical Engineering, Iby and Aladar Fleischman Faculty of Engineering, Tel Aviv University, Ramat Aviv 69978 (Israel)

2009-08-10

60

Piezoelectric and Dielectric Properties of Dy2O3-Doped Bi0.5 (Na0.82K0.18)0.5TiO3 Lead-Free Ceramics  

Microsoft Academic Search

xDy2O3-Bi0.5(Na0.82K0.18)0.5TiO3(0-0.4wt%) ceramics were synthesized by conventional solid-state processes. X-ray diffraction pattern confirmed that the tetragonal and rhombohedral phases co-existed in the Dy2O3 doped Bi0.5(Na0.82K0.18)0.5TiO3 ceramics from x = 0.05 to 0.4 wt% Dy2O3. SEM images indicate that doping of Dy2O3 promotes the formation of the ceramics with homogenous microstructures and high density. The Bi0.5(Na0.82K0.18)0.5TiO3 ceramics remain a diffuse phase transition

Chen Zhi-Hui; Ding Jian-Ning; Mei Lin; Yuan Ning-Yi; Zhang Wei-Wei

2011-01-01

61

Sintering and piezoelectric properties of KNN ceramics doped with KZT  

Microsoft Academic Search

This paper investigates the effect of K1.94 Zn1.06Ta5.19O15 (KZT) addition on the sintering behavior and piezoelectric properties in lead-free piezoelectric ceramics of (K0.5Na0.5)NbO3 (KNN). The apparent density of sintered KNN ceramics was increased with KZT addition, and a relative density of above 96.3% was obtained with the doping of over 0.5 mol% KZT. The maximum dielectric and piezoelectric properties of

Jungho Ryu; Jong-Jin Choi; Byung-Dong Hahn; Dong-Soo Park; Woon-Ha Yoon; Kun-Young Kim

2007-01-01

62

Effect of humidity on indentation crack growth in lead-free ferroelectric ceramics  

Microsoft Academic Search

The effect of humidity on growth of unloaded indentation crack in KNN free-lead ferroelectric ceramics has been investigated. The results showed that crack growth of unloaded indentation in lead-free ferroelectric ceramics could occur in humid air of 70% and 90%RH without electric field and mechanical stresses, but did not in air with RH<=30%. The growth of indentation crack could occur

H. J. Zhang; J. X. Li; W. Y. Chu; Y. J. Su; L. J. Qiao

2009-01-01

63

Ferroelectric domain structure of lead-free potassium-sodium niobate ceramics  

Microsoft Academic Search

The complex domain structure of orthorhombic (K0.5Na0.5)NbO3 (KNN) piezoelectric ceramics has been studied by SEM. The study was performed in samples prepared by microwave-hydrothermal synthesis. The identification of the domain structure has been afforded in KNN ceramics. Abnormal grain growth was observed in the microstructure of KNN ceramics, with an average grain size of 63?m. Most of the ferroelectric domains

Rigoberto Lpez-Jurez; Omar Novelo-Peralta; Federico Gonzlez-Garca; Fernando Rubio-Marcos; Mara-Elena Villafuerte-Castrejn

2011-01-01

64

Porous Piezoelectric Ceramic Transducer  

NASA Astrophysics Data System (ADS)

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 in an echo sounder of 200 kHz, and its transmitting and receiving properties were measured in water. In these measurements, the P-PZT showed suitable characteristics for the echo sounder, which required high sensitivity, wide frequency bandwidth and high resolution. High sensitivity was realized by the large g constant and low Zc of P-PZT which made the impedance matching with water much easier. In the acoustic response to the burst wave, the rise and fall time were shortened to 1/3 that of the conventional PZT transducer.

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

1991-09-01

65

Low-temperature sintering and electrical properties of (K, Na)NbO 3 based lead-free ceramics with high Curie temperature  

Microsoft Academic Search

Lead-free ceramics (1?x)(K0.48Na0.52)NbO3(x\\/5.15)K2.9Li1.95Nb5.15O15.3 (x=0.30.6, KNNKLN100x) were prepared by conventional sintering technique at a low temperature of 960C. The effects of KLN contents on microstructure, dielectric, and piezoelectric properties were investigated. After the addition of KLN, the sintering performance and Curie temperature of the ceramics were markedly improved. The ceramics with x=0.3 exhibited very good piezoelectric properties: d33=138pC\\/N, kp=45.03%, Tc=495C, the

You-Liang Wang; Yi-Qing Lu; Meng-Jia Wu; Dong Wang; Yong-Xiang Li

66

Dielectric and piezoelectric properties of lead-free (Bi,Na)TiO3-based thin films  

NASA Astrophysics Data System (ADS)

Dielectric and piezoelectric properties of morphotropic phase boundary (Bi,Na)TiO3-(Bi,K)TiO3-BaTiO3 epitaxial thin films deposited on SrRuO3 coated SrTiO3 substrates were reported. Thin films of 350 nm thickness exhibited small signal dielectric permittivity and loss tangent values of 750 and 0.15, respectively, at 1 kHz. Ferroelectric hysteresis measurements indicated a remanent polarization value of 30 ?C/cm2 with a coercive field of 85-100 kV/cm. The thin film transverse piezoelectric coefficient (e31,f) of these films after poling at 600 kV/cm was found to be -2.2 C/m2. The results indicate that these BNT-based thin films are a potential candidate for lead-free piezoelectric devices.

Abazari, M.; Safari, A.; Bharadwaja, S. S. N.; Trolier-McKinstry, S.

2010-02-01

67

Nonlinear behavior in piezoelectric ceramic transducers  

Microsoft Academic Search

In recent years intensive development efforts have been devoted to new piezoelectric high-power devices, such as ultrasonic motors, piezoelectric actuators, and piezoelectric transformers. Piezoelectric ceramic transducers used in these devices are usually driven at a high level of vibration stress in a resonant mode. To optimize the performance of such devices, it is essential to understand the nonlinear behavior which

S. Takahashi; Y. Sasaki; M. Umeda; K. Nakamura; S. Ueha

2000-01-01

68

Electrical properties of (1-x)(Bi0.5Na0.5)TiO3-xKNbO3 lead-free ceramics  

NASA Astrophysics Data System (ADS)

In this investigation, a simple compound (1-x)(Bi0.5Na0.5)TiO3-xKNbO3 (BNT-xKN, x=0-0.08) lead-free ceramics were synthesized successfully by conventional solid state reaction method. The piezoelectric, dielectric and ferroelectric characteristics of the ceramics were investigated and discussed. The results shows that moderate KN addition can enhance the piezoelectric response without an obvious decline of ferroelectric properties. The largest piezoelectric response is obtained in BNT-0.05KN, whereas largest electric-field-induced strain is obtained in BNT-0.06KN. An effective d33eff of ~400 pC/N calculated from electric-field-induced strain is obtained in BNT-0.06KN. The present investigation demonstrates that addition KN effectively reduces the depolarization temperature of the BNT-xKN ceramics. The electrical properties of the ceramics are tightly related to their depolarization temperature.

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

2014-05-01

69

Effect of Dopant on Piezoelectric Properties of Lead-Free BiFeO3--BaTiO3 Film  

Microsoft Academic Search

To realize high-performance lead-free piezoelectric materials, we have selected BiFeO3 as the rhomboheral phase material and BaTiO3 as the tetragonal phase material, following the MPB mechanism of PZT. To further improve the piezoelectric properties of BiFeO3--BaTiO3 (BFBT) thin films, we investigated the effect of dopant on the piezoelectric properties of BFBT. Considering both Shanon effective ionic radii and valence number,

Tsutomu Sasaki; Yasutoshi Hirabayashi; Hiroyuki Kobayashi; Yukio Sakashita

2011-01-01

70

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

71

Nonlinear behavior of BNT-based lead-free piezoceramics under various ac fields  

Microsoft Academic Search

In this study, two different bismuth sodium titanate (BNT) based lead-free piezoelectric ceramics, BNKBT-5 and BNKLBT-1.5, were fabricated and their nonlinear piezoelectric behaviour were compared. The ac field dependent piezoelectric properties of both lead-free materials were investigated. An analysis of the changes in real parts of the materials parameters (e.g. stiffness, permittivity and electromechanical coupling coefficient) and the loss factors

S. H. Choy; H. L. W. Chan

2011-01-01

72

Templated Grain Growth of Textured Piezoelectric Ceramics  

Microsoft Academic Search

Crystallographic texturing of polycrystalline ferroelectric ceramics offers a means of achieving significant enhancements in the piezoelectric response. Templated grain growth (TGG) en- ables the fabrication of textured ceramics with single crystal-like properties, as well as single crystals. In TGG, nucleation and growth of the desired crystal on aligned single crystal template particles results in an increased fraction of oriented material

G. L. Messing; S. Trolier-McKinstry; E. M. Sabolsky; C. Duran; S. Kwon; B. Brahmaroutu; H. Yilmaz; P. W. Rehrig; K. B. Eitel; E. Suvaci; M. Seabaugh; K. S. Oh

2004-01-01

73

Models and Characterization of Piezoelectric Ceramics  

NASA Astrophysics Data System (ADS)

Selected literature on the use of linearized constitutive equations and complex piezoelectric coefficients to develop models and characterize materials is presented in brief. One-dimensional models of simple piezoelectric ceramic components are derived using linearized constitutive equations and other fundamental relations to illustrate the procedure used to develop multi-dimensional models. Then, the procedure for building models of multi-layer devices using models of components is illustrated. Models are also used to characterize materials. A method to determine the errors when the ANSI/IEEE Standard method is used to determine real piezoelectric coefficients and methods to characterize non-Standard shapes often used in devices are also presented

Ebenezer, D. D.

2008-07-01

74

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

2012-12-15

75

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

NASA Astrophysics Data System (ADS)

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

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

2011-03-01

76

Embedded piezoelectric ceramic transducers in sandwiched beams  

Microsoft Academic Search

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

Venu Gopal Madhav Annamdas; Chee Kiong Soh

2006-01-01

77

Non-Linear Behaviour of Piezoelectric Ceramics  

Microsoft Academic Search

\\u000a By their ferroelectric nature, ferro-piezoelectric ceramics have a non-linear behaviour. This nature is reinforced by their\\u000a notably complex grain and domain structure, which leads to a less linear behaviour than is expected for a single crystal.

Alfons Albareda; Rafel Prez

2011-01-01

78

Diffusion phase transition and dielectric characteristics of Bi 0.5Na 0.5TiO 3-Ba(Hf,Ti)O 3 lead-free ceramics  

NASA Astrophysics Data System (ADS)

Lead-free ceramics based on bismuth sodium titanate (Bi 0.5Na 0.5TiO 3, BNT)-barium hafnate titanate (Ba(Hf 0.05,Ti 0.95)O 3, BHT5) were prepared by a two-step sintering process. The BNT-BHT5 ceramics sintered at 1180 ?C for 2 h in air showed a pure perovskite structure. The results show that the phase transition temperature (Tm) is suppressed dramatically with a small amount of BHT5 content and then decreased gradually with more BHT5 in the compounds. The diffusion of the phase transition is more distinct for the samples around the morphotropic phase boundary (MPB) of BNT-BHT5 system. In the (1- x)BNT- xBHT5 system, high piezoelectric constants were obtained at x=0.08, which is a tetragonal phase near the MPB region. The BNT-BHT5 system is expected to be a new and promising candidate for lead-free dielectric and piezoelectric ceramics.

Tian, H. Y.; Wang, D. Y.; Lin, D. M.; Zeng, J. T.; Kwok, K. W.; Chan, H. L. W.

2007-04-01

79

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

80

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

PubMed Central

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

2012-01-01

81

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

PubMed

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

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

2014-06-01

82

Crystal Growth and Electrical Properties of Lead-Free Piezoelectric Material (Na1\\/2Bi1\\/2)TiO3-BaTiO3  

Microsoft Academic Search

Single crystals of lead-free piezoelectric material x(Na1\\/2Bi1\\/2)TiO3-yBaTiO3 (NBBT 100x\\/100y) have been successfully grown by the flux method and the Bridgman method. Using the flux method, crystals having an edge length of 2-8 mm were obtained using Bi2O3 flux with cooling from 1350C to 800C at a rate of 3.5C\\/h. Using the Bridgman method, comparatively good crystal of 15 mm diameter

Yasuharu Hosono; Kouichi Harada; Yohachi Yamashita

2001-01-01

83

Crack deflection in piezoelectric ceramics  

Microsoft Academic Search

Crack deflection can occur in a specimen subject to a stress gradient of high tensile stresses near the surface which decreases with increasing depth. Such a stress gradient can be induced by strain incompatibilities. These can for example arise under electric fields between the electroded and external regions of a piezoelectric material. Such incompatibilities have been realized in thin rectangular

H.-A. Bahr; V.-B. Pham; D. C. Lupascu; H. Balke; J. Rdel; U. Bahr

2003-01-01

84

Impact Shock on Piezoelectric Ceramics.  

National Technical Information Service (NTIS)

Life expectancy tests performed on ceramic rings of compositions EC-55, EC-64, EC-65 and EC-69 have resulted in extensive data regarding the effects of impact shocks on the physical and electrical characteristics of the ceramic rings. The results have ind...

C. W. Skinner W. T. Kiyota R. C. Lowrie

1967-01-01

85

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.

Prez, Nicols; Buiochi, Flavio; Andrade, Marco A. B.; Adamowski, Julio C.

2012-05-01

86

Laser Deflection by a Torsionally Resonant Horn Loaded Piezoelectric Ceramic.  

National Technical Information Service (NTIS)

An ultrasonic laser deflector employing a torsionally oscillating piezoelectric transducer and mechanical transformer is described. A half-wave piezoelectric ceramic is cemented to a half-wave stepped horn to magnify the small amplitude torsional vibratio...

R. J. Klaiber

1967-01-01

87

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

NASA Astrophysics Data System (ADS)

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

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

2013-03-01

88

Elastic wave propagation in porous piezoelectric ceramics  

Microsoft Academic Search

The elastic wave propagation in piezoelectric ceramics with pore volume fractions up to 0.6 has been investigated. The samples have been prepared by tape casting starting from lead zirconate-titanate (PZT) powder with mean particle diameter 1.4 ?m. Sample analysis performed by intrusion mercury porosimeter revealed interconnected porosity with narrow size distribution. The samples were cleaned, silver metallized on two opposite

F. Craciun; G. Guidarelli; C. Galassi; E. Roncari

1998-01-01

89

Textured-Ba(Zr,Ti)O 3 piezoelectric ceramics fabricated by templated grain growth (TGG)  

Microsoft Academic Search

Ba(Zr0.085Ti0.915)O3 (BZT) ceramics were grain-oriented (textured) in the -orientation using the Templated Grain Growth (TGG) process. The\\u000a piezoelectric response of the textured samples was enhanced when poled and measured in the -textured direction. The d33-coefficients for samples measured with a low drive field (33-coefficients were at least three times greater than randomly-oriented BZT ceramics and equally greater than many lead-free

Edward M. Sabolsky; Libeth Maldonado; Matthew M. Seabaugh; Scott L. Swartz

2010-01-01

90

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

SciTech Connect

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

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

2012-02-15

91

Remanent-polarization-induced enhancement of photoluminescence in Pr3+-doped lead-free ferroelectric (Bi0.5Na0.5)TiO3 ceramic  

NASA Astrophysics Data System (ADS)

We found that ferroelectric remanent polarization can remarkably enhance the photoluminescence intensity of Pr3+-doped lead-free (Bi0.5Na0.5)TiO3 ceramics. An enhancement in photoluminescence intensity of ~35% was obtained in the 0.5 mol. % Pr3+-doped sample, attributed to the decrease of crystal symmetry that occurs in poled ferroelectric ceramics. Our results reveal the great potential to enhance the photoluminescence intensity in rare-earth doped ferroelectric ceramics through ferroelectric polarization and to monitor the ferroelectric remanent polarization strength through measuring the photoluminescence spectra. We also found that the threshold of Pr3+ concentration quenching increased in the poled Pr3+-doped lead-free (Bi0.5Na0.5)TiO3 ceramic sample.

Tian, Xiangling; Wu, Zheng; Jia, Yanmin; Chen, Jianrong; Zheng, R. K.; Zhang, Yihe; Luo, Haosu

2013-01-01

92

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

NASA Astrophysics Data System (ADS)

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

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

2013-02-01

93

Electrical properties of lead-free (1-x)(Na0.5K0.5)NbO3-xBa(Zr0.52Ti0.48)O3ceramics  

NASA Astrophysics Data System (ADS)

Lead-free (1-x)NKN-xBZT ceramics were fabricated by a conventional mixed oxide method. The results indicate that the content of BZT significantly influences the sintering, microstructure and electrical properties of (1-x)NKN-xBZT ceramics. For the (1-x)NKN-xBZT ceramics sintered at 1100C, the bulk density increased with increasing content of BZT until reaching a maximum value at a content of 0.3BZT. The dielectric constant, piezoelectric constant and electromechanical coupling factor of the (1-x)NKN-xBZT ceramics increased with adding BZT content at a low BZT content, in spite of the deformation of the NKN lattice, which might be due to the increase in their density. The optimum properties d 33 = 155 pC/N, k p = 36%, ? = 393 and P r = 9.8 ?C/cm2 were obtained for the 0.97NKN-0.03BZT ceramics sintered at 1100C for 4 h.

Lee, Dong-Hyun; Lee, Seung-Hwan; Choi, Eui-Sun; Lee, Sang-Chul; Lee, Young-Hie

2011-09-01

94

Origin of high piezoelectric activity in perovskite ferroelectric ceramics  

NASA Astrophysics Data System (ADS)

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

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

2014-06-01

95

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

NASA Astrophysics Data System (ADS)

We investigate the R3c average structure and micro-structure of the ceramic Bi0.5Na0.5TiO3 (BNT) in situ under applied electric fields using diffraction techniques. Electron diffraction implies the presence of significant octahedral tilt twin disorder, corresponding to the existence of a fine scale intergrown microstructural (IGMS) 'phase' within the R3c rhombohedral average structure matrix. A careful neutron refinement suggests not only that the off-centre displacements of the cations relative to the oxygens in the R3c regions increases systematically on application of an electric field but also that the phase fraction of the IGMS regions increases systematically. The latter change in phase fraction on application of the electric field enhances the polar displacement of the cations relative to the oxygen anions and affects the overall strain response. These IGMS regions form local polar nano regions that are not correlated with one another, resulting in polarisation relaxation and strain behaviour observed in BNT-containing materials.

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

2012-03-01

96

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

97

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

98

Measurement Methods for Investigating Degradation in Piezoelectric Ceramics.  

National Technical Information Service (NTIS)

Methods for testing the fatigue induced degradation of piezoelectric ceramics have been investigated. Measurements under cyclic electrical loading have proven difficult due to dielectric losses leading to sample heating, but several methods to overcome th...

M. Stewart

1996-01-01

99

Long ranged structural modulation in the pre-morphotropic phase boundary cubic-like state of the lead-free piezoelectric Na1/2Bi1/2TiO3-BaTiO3  

NASA Astrophysics Data System (ADS)

The nature of the pre-morphotropic phase boundary (MPB) cubic-like state in the lead-free piezoelectric ceramics (1-x)Na1/2Bi1/2TiO3-(x)BaTiO3 at x 0.06 has been examined in detail by electric field and temperature dependent neutron diffraction, x-ray diffraction, dielectric and ferroelectric characterization. The superlattice reflections in the neutron diffraction patterns cannot be explained with the tetragonal P4bm and the rhombohedral (R3c) phase coexistence model. The cubic like state is rather a result of long ranged modulated complex octahedral tilt. This modulated structure exhibits anomalously large dielectric dispersion. The modulated structure transforms to a MPB state on poling. The field-stabilized MPB state is destroyed and the modulated structure is restored on heating the poled specimen above the Vogel-Fulcher freezing temperature. The results show the predominant role of competing octahedral tilts in determining the nature of structural and polar states in Na1/2Bi1/2TiO3-based ferroelectrics.

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

2013-12-01

100

Passive Vibration Damping Materials: Piezoelectric Ceramic Composites for Vibration Damping Applications.  

National Technical Information Service (NTIS)

The use of passive piezoelectric damping using PZT ceramics has been demonstrated in theory and the number of experiments. The effort was multifaceted. For application of the shunted passive piezoelectric damping of structural composites, piezoelectric ce...

S. Yoshikawa R. Meyer J. Witham S. Y. Agadda G. Lesieutre

1995-01-01

101

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

NASA Astrophysics Data System (ADS)

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

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

2012-09-01

102

Biomedical instrumentation based on piezoelectric ceramics  

Microsoft Academic Search

New sensors and actuators based on emerging transducer technologies can play a crucial role in the field of biomedical instrumentation and rehabilitation technologies. Piezoelectricity and transducers based on the piezoelectric effect might lead to the adoption of compact sensor and actuator solutions in this field. This paper addresses a review of piezoelectric and piezoresistive transducer applications in the field of

J. L. Pons; E. Rocon; A. Forner-Cordero; J. Moreno

2007-01-01

103

Loss Factor Characterization Methodology for Piezoelectric Ceramics  

Microsoft Academic Search

The key factor for the miniaturization of piezoelectric devices is power density, which is limited by the heat generation or loss mechanisms. There are three loss components for piezoelectric vibrators, i.e., dielectric, elastic and piezoelectric losses. The mechanical quality factor, determined by these three factors, is the figure of merit in the sense of loss or heat generation. In this

Yuan Zhuang; Seyit O. Ural; Kenji Uchino

2011-01-01

104

Nonlinear Behavior and High-Power Properties of (Bi,Na,Ba)TiO3 and (Sr,Ca)2NaNb5O15 Piezoelectric Ceramics  

Microsoft Academic Search

The nonlinear behaviors and high-power properties of two lead-free piezoelectric ceramics --- (Bi1\\/2Na1\\/2)0.85Ba0.15Ti0.98Mn0.02O3 (BNBTM) and Sr1.9Ca0.1NaNb5O15 (SCNN) --- were clarified by comparison of their mechanical characteristics using the continuous driving method. BNBTM ceramics exhibited jump phenomena with constant-voltage driving that were similar to those found in Pb(Zr,Ti)O3-based (PZT) ceramics. The jump phenomena of SCNN ceramics produced mirror-reversed images relative to

Yutaka Doshida; Hiroyuki Shimizu; Youich Mizuno; Keita Itoh; Seiji Hirose; Hideki Tamura

2011-01-01

105

Lead zirconate titanate-lead silicate piezoelectric glass-ceramics  

Microsoft Academic Search

Piezoelectric glass-ceramics consisting of lead zirconate titanate in a lead silicate matrix have been developed. A small region of compositions in this system yield the desired combination of glass formability, densification and crystallization behavior, and piezoelectric properties. SiO2 is required for glass formability, while excess PbO allows low temperature processing. The amounts of these constitutes are limited by the optimization

B. Houng; M. J. Haun

1994-01-01

106

Development of optical phase shifter based on piezoelectric ceramic  

NASA Astrophysics Data System (ADS)

The phase shifter is necessary in the optical phase-shifting measurement. At present the phase shifter commonly used is approximately divided into the penetrance-type and the reflection-type. In this paper, a reflection-type phase shifter made of piezoelectric ceramic stackup assemble is developed. The assemble are constituted of the flat piezoelectric ceramic with parallel connection circuit and inline structure. The communication between the computer and MCU is by RS232. The D/A converter controlled by the MCU outputs 0~10V voltage. Then the voltage is amplified to 0~400V DC voltage by the designed linear DC amplifier. When this voltage loads on the piezoelectric ceramic stackup assemble, the assemble will axially extend 0~5mm. In this paper, the connecting types for the mechanical construction and circuit of the piezoelectric ceramic stackup assemble, the driving power and the DC amplifier with high linearity are all introduced. The whole system developed is standardized by using phase-interfering Michelson. The standardization and the practical application indicates that this system has excellent linearity and precision repeatability.

Yu, Fusheng; Shen, Xiaoqin; Yao, Chunjuan; Leng, Changlin

2005-02-01

107

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

PubMed

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

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

2014-07-14

108

Electrical modeling of Piezoelectric ceramics for analysis and evaluation of sensory systems  

Microsoft Academic Search

Piezoelectricity is an ability of some materials to generate an electric potential in response to applied mechanical stress. Piezoelectric ceramics are often used for sensory systems to monitor mechanical characteristics of structures through an electrical signal. Thus, to support system level analysis and evaluation of sensory systems, understanding and estimating the electrical behavior of piezoelectric ceramics with a minimum effort

Jina Kim; Benjamin L. Grisso; Jeong K. Kim; Dong Sam Ha; Daniel J. Inman

2008-01-01

109

Piezoelectric Properties of a Porous PZT Ceramic.  

National Technical Information Service (NTIS)

A porous PZT material from a Japanese source was characterized for its piezoelectric properties. Initial values of 82 pC/N for the hydrostatic d constant and 0.046 Vm/N for the hydrostatic g constant were observed. The material also showed no pressure hys...

R. Y. Ting

1985-01-01

110

COLD SPRAY ELECTRODING OF PIEZOELECTRIC CERAMIC  

Microsoft Academic Search

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

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

111

Nonlinear Behavior and High-Power Properties of (Bi,Na,Ba)TiO3 and (Sr,Ca)2NaNb5O15 Piezoelectric Ceramics  

NASA Astrophysics Data System (ADS)

The nonlinear behaviors and high-power properties of two lead-free piezoelectric ceramics --- (Bi1/2Na1/2)0.85Ba0.15Ti0.98Mn0.02O3 (BNBTM) and Sr1.9Ca0.1NaNb5O15 (SCNN) --- were clarified by comparison of their mechanical characteristics using the continuous driving method. BNBTM ceramics exhibited jump phenomena with constant-voltage driving that were similar to those found in Pb(Zr,Ti)O3-based (PZT) ceramics. The jump phenomena of SCNN ceramics produced mirror-reversed images relative to those of BNBTM ceramics. Their nonlinear behaviors were caused by the soft-spring effect and hard-spring effect, respectively. Among the piezoelectric materials, SCNN ceramics possess notable elastic properties. With increasing vibration velocity, their rise in temperature was lower than that of PZT ceramics; in particular, the temperature of SCNN ceramics was lower than that of BNBTM ceramics. The quality factor of BNBTM ceramics gradually decreased and that of SCNN ceramics showed a broad peak. The degradation of the quality factor was thus limited, resulting in a gradual increase in the equivalent mechanical resistance.

Doshida, Yutaka; Shimizu, Hiroyuki; Mizuno, Youich; Itoh, Keita; Hirose, Seiji; Tamura, Hideki

2011-09-01

112

Passive Vibration Damping Materials: Piezoelectric Ceramics Composites for Vibration Damping Applications.  

National Technical Information Service (NTIS)

For application of the shunted passive piezoelectric damping of structural composites, piezoelectric ceramic fibers (PZT and its family) of several tens of micron diameter were made using sol-gel spinning process. Both acetate and acetylacetonate processe...

S. Yoshikawa S. K. Kurtz

1993-01-01

113

Ca0.5Sr0.5TiO3-Modified KNN-Based Lead-Free Piezoceramics with a Wide Temperature Usage Span  

NASA Astrophysics Data System (ADS)

The strong temperature dependence of dielectric and piezoelectric properties is a big bottleneck for practical applications of KNN-based piezoceramics. In order to resolve this problem, Ca0.5Sr0.5TiO3 (CST) is doped into (Na0.53K0.407Li0.063)Nb0.937Sb0.063O3 (NKLNS) ceramics. The thermal stability of sE11 and k31 in the temperature range from -50C to 200C for ceramics with 1.0 and 1.5 mol% CST is raised in comparison with ceramics without CST. Ceramics with 1.5 mol% CST exhibit high piezoelectric properties (d33 = 202 pC/N, kp = 44%) and low dielectric loss (2%) at room temperature. The excellent piezoelectric properties, which are comparable to conventional PZT ceramics, indicate that these ceramics are promising candidates for lead-free piezoelectric applications.

Du, Juan; Wang, Jin-Feng; Zang, Guo-Zhong; Yi, Xiu-Jie

2011-06-01

114

Poling Field Dependence of Longitudinal and Transverse Wave Velocities, Young's Modulus, and Poisson's Ratio in Piezoelectric Ceramics  

NASA Astrophysics Data System (ADS)

The longitudinal and transverse wave velocities in lead zirconate titanate (PZT), lead titanate, and lead-free ceramics vs DC poling fields were measured using an ultrasonic precision thickness gauge with high-frequency pulse oscillation to evaluate elastic constants, such as Young's modulus and Poisson's ratio. With the enhancement of domain alignment with the increase in poling field, the longitudinal wave velocity increased and the transverse wave velocity decreased independently of the ceramic composition. It was found that there was an important factor for obtaining a high piezoelectricity regarding Young's modulus and Poisson's ratio, that is, the low Young's modulus and high Poisson's ratio in the cases of PZT, alkali bismuth titanate, and alkali bismuth barium titanate with morphotropic phase boundaries (MPBs), and alkali niobate without MPBs. Furthermore, the increase in planar coupling factor corresponds to the increase in Poisson's ratio at all compositions including lead-containing and lead-free ceramic compositions. It was possible to divide the ceramics on the basis of longitudinal and transverse wave velocities into three groups, namely, PZT and lead titanate modified by 2.5 mol % lanthanum, alkali bismuth titanate and lead titanate modified by 10 mol % lanthanum, and alkali niobate.

Ogawa, Toshio; Ishii, Keisuke; Matsumoto, Tsubasa; Nishina, Takayuki

2012-09-01

115

Structural integrity of composites with embedded piezoelectric ceramic transducers  

Microsoft Academic Search

The objective of this paper is to determine the strength reduction due to the embedment of a piezoelectric ceramic transducer in a composite. The composite was made from carbon\\/epoxy prepreg with a cross-ply lay-up. The transducer was embedded in the mid-plane of the composite material. The specimens were tested in tensile and compressive static loading. It was found that the

Christophe A. Paget; Klas Levin

1999-01-01

116

Investigation of energy absorption capabilities of piezoelectric ceramic  

Microsoft Academic Search

This paper presents an experimental investigation into the damping characteristics of piezoelectric ceramic PZT-5H. The material is subjected to cyclic uniaxial compressive stress (up to 200 MPa) at a constant electric field bias (from 0 to 2 MV\\/m). The experiments are conducted at 25 degree(s)C, 0 degree(s)C, and 50 degree(s)C. Fraction of energy absorbed (a specific damping capacity_ and elastic

Pavel M. Chaplya; Gregory P. Carman

2001-01-01

117

Stress corrosion cracking of a PZT piezoelectric ceramics  

Microsoft Academic Search

Stress corrosion cracking (SCC) of a leadzirconatetitanate (PZT) piezoelectric ceramics in water, methanol and formamide has been investigated at constant load test using a single-edge notched tensile specimen. The result showed that SCC or static fatigue fracture could occur in the three solutions, and the normalized threshold stress intensity factor of SCC was KISCC\\/KIC=0.66 (in water), 0.73 (in methanol) and

Y. Wang; W. Y. Chu; Y. J. Su; L. J. Qiao

2003-01-01

118

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

119

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

120

Effect of Ball Milling Time on the Electrical and Piezoelectric Properties of Barium Titanate Ceramics  

Microsoft Academic Search

Barium Titanate (BaTiO3) is the first piezoelectric ceramic developed and most widely used though for few decades it has been replaced by better performed lead based materials like PZT, PLZT, etc. for piezoelectric applications. Recently, however, due to the environmental concern caused by lead based materials, researchers have been giving importance to this material and trying to improve its piezoelectric

A. K. Nath; Chongtham Jiten; K. Chandramani Singh; Radhapiyari Laishram; O. P. Thakur; D. K. Bhattacharya

2010-01-01

121

Mechanisms in damping of mechanical vibration by piezoelectric ceramic-polymer composite materials  

Microsoft Academic Search

The piezoelectric ceramic (piezoceramic) component of a polymer-piezoelectric ceramic composite converts mechanical energy\\u000a into electrical energy and this electrical energy is dissipated as heat in a load resistance, R\\u000a x, simulated by a shunted resistance, but provided in practice by a conductive polymer composite matrix. The composite therefore\\u000a dissipates the input mechanical energy via the damping mechanism provided by piezoelectric

H. H. Law; P. L. Rossiter; L. L. Koss; G. P. Simon

1995-01-01

122

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

123

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

124

The Investigation of PMS-PNW-PZT Piezoelectric Ceramics  

Microsoft Academic Search

Pb0.95Sr0.05[(Mn1\\/3Sb2\\/3)0.06(Ni1\\/2W1\\/2)x(Zr0.49Ti0.51)1-x-0.06]O3 (PMS-PNW-PZT) (x = 0.01?0.04) were prepared by using traditional technique with solid reaction process. The effects of PNW contents and sintering temperatures on microstructure, dielectric and piezoelectric properties of PMS-PNW-PZT ceramics were investigated. When the amount of doping content was about 2mol% and the sintering temperature was 1250C, the optimum values of buck density, mechanical quality factor, dielectric loss,

Zhang Dong; Ma Weibing; Sun Qingchi; Gao Hongye; Zhang Yong

2010-01-01

125

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

NASA Astrophysics Data System (ADS)

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

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

2013-04-01

126

Evaluation of Piezoelectric Properties of Bi4Ti3O12Based Ceramics at High Temperature  

Microsoft Academic Search

Nowadays many industries as aeronautic, aerospace, etc, are claiming for new sensors and actuators that can operate in hostile environments. PZT ceramics are the common materials used in piezoelectric devices, however their low Curie temperature prevents their use at high temperatures. Bi4Ti3O12-based ceramics show a great potential for high temperature applications. Although piezoelectric parameters of BIT ceramics are well described

Marina Villegas; Amador C. Caballero; Teresa Jardiel; Carmen Arag; Jon Maudes; Iaki Caro

2009-01-01

127

Multiscale energy release rates in fracture of piezoelectric ceramics  

NASA Astrophysics Data System (ADS)

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

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

1997-06-01

128

Study on the sandwich piezoelectric ceramic ultrasonic transducer in thickness vibration  

NASA Astrophysics Data System (ADS)

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 lateral displacements in the transducer can occur (laterally clamped). In this paper, the thickness vibration of the piezoelectric ceramic stack consisting of a number of identical piezoelectric ceramic thin rings is analysed and its electro-mechanical equivalent circuit is obtained. The resonance frequency equation for the sandwich piezoelectric ceramic ultrasonic transducer in thickness vibration is derived. Based on the frequency equation, two sandwich piezoelectric ceramic ultrasonic transducers are designed and manufactured, and their resonance frequencies are measured. It is shown that the measured resonance frequencies are in good agreement with the theoretical results. This kind of sandwich piezoelectric ultrasonic transducer is expected to be used in megasonic ultrasonic cleaning and sonochemistry where high power and high frequency ultrasound is needed.

Lin, Shuyu; Tian, Hua

2008-02-01

129

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

PubMed

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

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

2011-10-01

130

Structural and dielectric properties of a new lead-free ferroelectric Ba0.8Ca0.2Ti0.8Ge0.2O3 ceramics  

NASA Astrophysics Data System (ADS)

This paper reports the development of a lead free Ba0.8Ca0.2Ti0.8Ge0.2O3 (BCTG) ceramics elaborated by a conventional sintering process. The BCTG exhibits interesting ferroelectric and dielectric properties. The XRD analysis showed that 20 at.% of Ge doping can be fully incorporated into the perovskite lattice of Ba1-xCaxTiO3. Dielectric properties revealed that the BCTG ceramic undergone a second order phase transition type at around 120 C independently of the used frequency and behaves as displacive ferroelectric. Ferroelectric investigation showed that P-E hysteresis loop could be obtained at low applied electrical field. The BCTG compound may be highly promising for applications as lead-free ferroelectric materials to reduce environmental damages.

Asbani, B.; Lahmar, A.; Amjoud, M.; Dellis, J.-L.; Gagou, Y.; Mezzane, D.; El Marssi, M.

2014-07-01

131

EFFECT OF BiFeO3 DOPING ON FERROELECTRIC AND PIEZOELECTRIC PROPERTIES OF (Bi0.5Na0.5)TiO3 AND BaTiO3 CERAMICS  

Microsoft Academic Search

The effects of BiFeO3 (BF) doping on the phase transition temperatures especially of lead-free piezoelectric materials were studied. Up to 20 mole% of BFO was doped in (Bi0.5Na0.5)TiO3 (BNT) and BaTiO3 (BT) ceramics synthesized by solid state reactions. In BNT, ferroelectric transition temperature (TC) increased with doping but depolarization temperature (Td) was almost independent of BF contents. In BT, however,

K. H. RYU; T. K. SONG; M.-H. KIM; S. H. LEE; Y. S. SEONG; S. J. JEONG; J. S. SONG

2006-01-01

132

Active Optical Fiber Alignment with a Piezoelectric Ultrasonic Motor Integrated Into Low Temperature Cofired Ceramics  

Microsoft Academic Search

The major goal of this research was to integrate an ultrasonic motor into a ceramic package for an active optical fiber alignment. Two degrees of freedom ultrasonic motor was successfully cofired with commercial low temperature cofired ceramic green tapes as well as with silver electrodes without encountering serious delamination, camber, and inter diffusion issues. High-power piezoelectric ceramics that can be

Seung-Ho Park; Amanda Baker; Richard E. Eitel; Clive A. Randall; Kenji Uchino

2010-01-01

133

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

134

Investigation of energy absorption capabilities of piezoelectric ceramic  

NASA Astrophysics Data System (ADS)

This paper presents an experimental investigation into the damping characteristics of piezoelectric ceramic PZT-5H. The material is subjected to cyclic uniaxial compressive stress (up to 200 MPa) at a constant electric field bias (from 0 to 2 MV/m). The experiments are conducted at 25 degree(s)C, 0 degree(s)C, and 50 degree(s)C. Fraction of energy absorbed (a specific damping capacity_ and elastic modulus are evaluated as a function of bias electric field. For investigated stress amplitudes, the specific damping capacity increases with increasing bias field, reaches a maximum (28-33%) at the optimum field level, and then decreases. The optimum electric field values increase as the stress amplitude increases because the positive electric field and the compressive stress counteract each other in terms of domain wall motion. The damping properties are stable in the investigated temperature range. The piezoceramic is found to have superior damping properties compared to common structural methods.

Chaplya, Pavel M.; Carman, Gregory P.

2001-07-01

135

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

136

Nonlinear Theory for a Thin-Walled Piezoelectric Ceramic Ring Excited in the Radial Breathing Mode.  

National Technical Information Service (NTIS)

The nonlinear differential equation governing a thin-walled piezoelectric ceramic ring excited in the radial breathing mode is derived from the field equation of motion for an elastic continuum, the expanded nonlinear constitutive equations, and the appro...

R. W. Dunham

1975-01-01

137

Shear-horizontal surface waves in a layered structure of piezoelectric ceramics.  

PubMed

A new existence condition for shear-horizontal (SH) surface waves in a layered structure of piezoelectric ceramics is give. The discussed SH surface wave is not a stiffened Love wave, but a new type surface wave. PMID:18263171

Hanhua, F; Xingjiao, L

1993-01-01

138

Electrically driven cracks in piezoelectric ceramics: experiments and fracture mechanics analysis  

Microsoft Academic Search

Piezoelectric systems like multilayer actuators are susceptible to damage by crack propagation induced by strain incompatibilities. These can arise under electric fields for example between the electroded and external regions. Such incompatibilities have been realised in thin rectangular model specimens from PZT-piezoelectric ceramics with top and bottom electrodes only close to one edge. Under an electric field, controlled crack propagation

H.-A. Bahr; V.-B. Pham; D. C. Lupascu; H. Balke; J. Rdel; U. Bahr

2002-01-01

139

Effect of cyclic loading on the parameters of elastic wave propagation in piezoelectric ceramics  

Microsoft Academic Search

Conclusions 1.Diagnostic methods based on elastic waves can be used for estimating fatigue changes in piezoelectric ceramics.2.The degree of fatigue damage in piezoelectric ceramic specimens can be determined with respect to the extent of elastic wave damping.3.The method of estimating the damage based on surface waves is more promising, since it allows recording of fatigue damage of lesser magnitude in

V. K. Khaustov; V. P. Leshchikov; G. G. Pisarenko

1987-01-01

140

Electrical Characteristics of Ultrasonic Nozzle Using Multilayer Ring-Type Piezoelectric Ceramics for Light Oil Spray  

Microsoft Academic Search

In this paper, ultrasonic nozzle and its driving circuit were manufactured. And then, their electrical properties were investigated. Ultrasonic nozzle using multilayer ring-type piezoelectric ceramics was fabricated by Pb[(Mn1\\/3Nb2\\/3)0.02(Ni1\\/3Nb2\\/3)0.12(Zr0.50Ti0.50)0.86]O3 (abbreviated as PMN-PNN-PZT) composition which have excellent piezoelectric characteristics. The multilayer ring-type piezoelectric ceramics using pure Ag inner electrode was sintered at 900C low temperatures. In order to drive ultrasonic nozzle,

Jinhee Kang; Yuhyong Lee; Larkhoon Hwang; Juhyun Yoo; Jaeil Hong

2010-01-01

141

Stress and frequency dependence of the direct piezoelectric effect in ferroelectric ceramics  

SciTech Connect

It is shown that at weak alternating stress the relationship between the piezoelectrically induced charge and applied stress in ferroelectric ceramics has the same form as the Rayleigh law for magnetization versus magnetic field in ferromagnetic materials. Applicability of the Rayleigh law to the piezoelectric effect is demonstrated in detail for lead zirconate titanate (PZT) ceramics. Experimental results indicate that the dominant mechanism responsible for piezoelectric hysteresis and the dependence of the piezoelectric coefficient on the applied ac stress is the pinning of non-180{degree} domain walls. The dependence of the piezoelectric coefficient on the frequency of the driving stress is examined and is shown to be due to the frequency dispersion of both reversible and irreversible components of domain-wall displacement. Analysis of the stress dependence of the piezoelectric phase angle reveals piezoelectric hysteresis contributions that are not necessarily due to Rayleigh-type displacement of domain walls. Piezoelectric properties of a modified lead titanate composition that exhibits non-Rayleigh type behavior are examined and compared with the properties of PZT ceramics. {copyright} {ital 1997 American Institute of Physics.}

Damjanovic, D. [Laboratory of Ceramics, Department of Materials, Swiss Federal Institute of Technology - EPFL, 1015 Lausanne (Switzerland)] [Laboratory of Ceramics, Department of Materials, Swiss Federal Institute of Technology - EPFL, 1015 Lausanne (Switzerland)

1997-08-01

142

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

PubMed

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

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

2011-09-01

143

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

144

Strong piezoelectricity exhibited by large-grained BaTiO3 ceramics  

NASA Astrophysics Data System (ADS)

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

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

2014-06-01

145

Lead-free alkaline niobate-based transducer for ultrasonic wirebonding applications  

Microsoft Academic Search

Lead-free piezoelectric ceramic rings (Na0.475K0.475Li0.05)(Nb0.92Ta0.05Sb0.03)O3 added with 0.4wt% CeO2 and 0.4wt% MnO2 have been successfully prepared and used as the driving elements of the ultrasonic wirebonding transducers with titanium alloy front and back plates. The transducer operates at similar frequency of the commercial lead zirconate titanate (PZT) transducers (?65kHz). Because of the better matching of the acoustic impedances between the

Tact Lee; K. W. Kwok; H. L. Li; H. L. W. Chan

2009-01-01

146

Study on the equivalent circuit and coupled vibration for the longitudinally polarized piezoelectric ceramic hollow cylinders  

NASA Astrophysics Data System (ADS)

Longitudinally polarized piezoelectric ceramic disks with central holes have been the most commonly used elements in underwater acoustics and ultrasonics. For very thin piezoelectric ceramic disks, its vibration can be regarded as one-dimensional thickness extensional vibration, or plane radial vibration, and the coupling between these two different vibrational modes is neglected. However, for practical piezoelectric ceramic disks with central holes, the geometrical dimensions do not satisfy the requirements for the thin ring, and the coupling must be considered. In this paper, the coupled vibration of the longitudinally polarized piezoelectric ceramic disks with central holes is studied using an approximate analytical method. When the mechanical coupling coefficient is introduced and the shearing strain is ignored, the coupled vibration of the piezoelectric ceramic hollow cylinder is divided into two equivalent vibrations. One is the equivalent longitudinal extensional vibration, and the other is the equivalent radial vibration. These two equivalent vibrations are not independent; they are correlated together by the mechanical coupling coefficient. The equivalent circuit for the piezoelectric ceramic hollow cylinders in coupled vibration is derived, and the resonance frequency equations are obtained. Based on the coupled frequency equations, the longitudinal and radial resonance frequencies can be obtained when the dimensions and the material parameters are given. Compared with one-dimensional theory, the computed resonance frequencies in this paper are in good agreement with the measured results. Compared with the numerical methods, the analytic method presented in this paper is simple in computing the longitudinal and radial resonance frequencies and in analyzing the coupled vibrational modes of the piezoelectric ceramic disks with central holes.

Lin, Shuyu

2004-08-01

147

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

NASA Astrophysics Data System (ADS)

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

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

2013-09-01

148

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

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

2011-09-01

149

Carbon-Fiber Reinforced Plastic Passive Composite Damper by Use of Piezoelectric Polymer\\/Ceramic  

Microsoft Academic Search

In this study, the passive damping of carbon-fiber reinforced plastic (CFRP) cantilever beams is examined using (1) interleaving of viscoelastic thermoplastic films, (2) piezoelectric polymer (PVDF) film interlayers and (3) surface-bonded piezoelectric ceramics. Introducing polyethylene-based film interlayers between composite plies resulted in a significant increase in the vibration loss factor. It is also shown that the vibration damping of CFRP

Toshio Tanimoto

2002-01-01

150

Experimental search for high Curie temperature piezoelectric ceramics with combinatorial approaches  

Microsoft Academic Search

High temperature piezoelectric materials are needed for actuation and sensing applications in harsh environments such as engine health monitoring and space exploration. Ferroelectric ceramics are widely used in piezoelectric devices but their high temperature application is limited by the ferroelectric-to-nonferroelectric transition at the Curie temperature.\\u000aThe BiFeO3-PbTiO3 (BF-PT) solid solution system is peculiar for its high Curie temperature and thus

Wei Hu

2011-01-01

151

Ferroelectric, dielectric and piezoelectric properties of ferroelectric thin films and ceramics  

NASA Astrophysics Data System (ADS)

Ferroelectric, dielectric and piezoelectric properties of ferroelectric thin films and ceramics are reviewed with the aim of providing an insight into different processes which may affect the behaviour of ferroelectric devices, such as ferroelectric memories and micro-electro-mechanical systems. Taking into consideration recent advances in this field, topics such as polarization switching, polarization fatigue, effects of defects, depletion layers, and depolarization fields on hysteresis loop behaviour, and contributions of domain-wall displacement to dielectric and piezoelectric properties are discussed. An introduction into dielectric, pyroelectric, piezoelectric and elastic properties of ferroelectric materials, symmetry considerations, coupling of electro-mechanical and thermal properties, and definitions of relevant ferroelectric phenomena are provided.

Damjanovic, Dragan

1998-09-01

152

Passive vibration damping materials: Piezoelectric ceramics composites for vibration damping applications  

NASA Astrophysics Data System (ADS)

For application of the shunted passive piezoelectric damping of structural composites, piezoelectric ceramic fibers (PZT and its family) of several tens of micron diameter were made using sol-gel spinning process. Both acetate and acetylacetonate processes were examined as lead sources. Using the properly chosen spinneret and fiber drawing apparatus, PZT and modified PZT fibers of 10 to l00 micrometers diameter have been successfully produced. Different heat treatments gave different microstructure. Modeling analysis was also performed to estimate achievable damping levels for the composites. The results indicate high damping potential for shunted piezoelectric passive damping composites.

Yoshikawa, Shoko; Kurtz, S. K.

1993-02-01

153

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

PubMed

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

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

2004-11-01

154

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

155

Study of the Dielectric Properties of Lead-Free Perovskite Ba(Fe1/2Ta1/2)O3 and Ba(Bi1/2Ta1/2)O3 Ceramics  

NASA Astrophysics Data System (ADS)

Lead-free complex perovskite ceramics Ba(Fe1/2Ta1/2)O3 and Ba(Bi1/2Ta1/2)O3 were synthesized using conventional solid state reaction technique. The crystal symmetry, space group and unit cell dimensions were determined from the experimental results using FullProf software. XRD analysis of the compound indicated the formation of a single-phase cubic structure with the space group Pm3m. A very high value of dielectric constant (~104) was observed for Ba(Fe1/2Ta1/2)O3 while for Ba(Bi1/2Ta1/2)O3 it is 639. The correlated barrier hopping (CBH) model was employed to successfully explain the mechanism of charge transport in Ba(Fe1/2Nb1/2)O3 and Ba(Bi1/2Ta1/2)O3.

Mishra, Amodini; Choudhary, S. N.; Prasad, K.; Choudhary, R. N. P.

2011-11-01

156

Temperature behavior of dielectric and piezoelectric properties of samarium-doped lead titanate ceramics  

Microsoft Academic Search

The dielectric and electromechanical coupling properties of Sm-doped and Mn-doped PbTiO3 ceramics were investigated from 4.2 to 300 K. The upper and lower limits of the ceramic dielectric and piezoelectric properties were calculated by averaging the single-domain constants that were determined from a phenomenological theory. Comparisons of the measured and calculated properties were then made. The measured dielectric permittivity ?T33

J. N. Kim; MICHAEL J. HAUN; SEI JOO JANG; L. E. Cross; X. R. Xue

1989-01-01

157

Annealing effects on the characteristics of high Tc lead-free barium titanate-based positive temperature coefficient of resistivity ceramics  

NASA Astrophysics Data System (ADS)

Annealing effects on the positive temperature coefficient of resistivity (PTCR) behavior of (Bi1/2Na1/2)TiO3 and (Bi1/2K1/2)TiO3 modified BaTiO3 semiconducting ceramics are investigated. The annealing treatments result in the occurrence of the PTCR effect and the increased resistivity jump. The impedance spectra reveal that the resistivity of grain interior of annealed sample is little influenced by the annealing process, indicating that the increase in the overall resistivity is entirely a grain-boundary effect. A higher annealing temperature leads to an increase in acceptor state density, potential barrier height and barrier layer width, which contributes to the improved PTCR effect in the annealed samples.

Xiang, Ping-Hua; Harinaka, Hisashi; Takeda, Hiroaki; Nishida, Takashi; Uchiyama, Kiyoshi; Shiosaki, Tadashi

2008-11-01

158

Combinatorial and High Throughput Discovery of High Temperature Piezoelectric Ceramics.  

National Technical Information Service (NTIS)

This project has developed a statistical learning approach to identify potential new high temperature ferroelectric piezoelectric perovskite compounds. Our predictions of the Curie temperature (Tc) ranging from 700C- 1100C are the highest reported in eith...

K. Rajan X. Tan

2011-01-01

159

Finite-element analysis of vibrational modes in piezoelectric ceramic disks  

Microsoft Academic Search

The natural vibrational modes of axially symmetric piezoelectric ceramic disks have been calculated by the finite-element method. The disks are of the type used as active elements in compressional wave ultrasonic transducers, and are electrically polarized in thickness with full electrodes on the disk's major faces. To optimize disk geometry for ultrasonic transducer application, the dependence of the vibrational modes

H. A. Kunkel; S. Locke; B. Pikeroen

1990-01-01

160

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

Microsoft Academic Search

In recent years, market demand has creared a need for high reproducibility in the frequency characteristics of piezoelectric ceramic filters and resonators that use the thickness extension mode. In order to increase this reproducibility, it is necessary mainly to improve accuracy in controlling the substrate thickness, and to reduce variations in elastic properties of substrate materials prior to the completion

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

1994-01-01

161

Investigation of thermal and dielectric properties of tin-doped piezoelectric ceramics based on barium titanate  

NASA Astrophysics Data System (ADS)

The temperature dependences of the permittivity and pyroelectric coefficient of BaTi1 - x Sn x O3 piezoelectric ceramics with a homogeneous composition and a tin concentration gradient have been studied. The thermal diffusion coefficient has been measured. The polarization profiles of the materials under study have been calculated by the thermal square wave method at a single frequency.

Malyshkina, O. V.; Movchikova, A. A.; Penzov, K. N.; Steinhausen, R.; Langhammer, H. T.; Beige, H.

2010-01-01

162

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

NASA Astrophysics Data System (ADS)

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

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

2013-07-01

163

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

NASA Astrophysics Data System (ADS)

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

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

2013-04-01

164

Nanodomains in morphotropic lead zirconate titanate ceramics: On the origin of the strong piezoelectric effect  

NASA Astrophysics Data System (ADS)

The outstanding piezoelectric properties of lead zirconate titanate (PZT) ceramics with compositions close to the morphotropic phase boundary of the quasibinary phase diagram of lead zirconate and lead titanate are still under debate. A combination of ex situ and in situ transmission electron microscopy and high resolution x-ray diffraction revealed that the extrinsic piezoelectric effect in morphotropic PZT is closely connected to the existence of nanodomains. The in situ transmission electron microscopy investigations with applied electric field show that mainly the nanodomains respond to the electric field while the microdomain structure does not change noticeably in our experiments.

Theissmann, Ralf; Schmitt, Ljubomira A.; Kling, Jens; Schierholz, Roland; Schnau, Kristin A.; Fuess, Hartmut; Knapp, Michael; Kungl, Hans; Hoffmann, Michael J.

2007-07-01

165

Modified cofiring behaviors between PMN-PNN-PZT piezoelectric ceramics and PZT-doped 70Ag30Pd alloy metallization  

Microsoft Academic Search

The cofiring behaviors between PMN-PNN-PZT piezoelectric ceramics and 70Ag30Pd electrode paste were investigated in view of sintering densification behavior, thermal expansion coefficients (TEC) and interfacial physical integrity. The results showed that mismatched cofiring characteristics have greatly affected the reliability of multilayer piezoelectric ceramic devices. The application of a PZT additive to 70Ag30Pd electrode technology has markedly improved the above-mentioned cofiring

Ruzhong Zuo; Longtu Li; Zhilun Gui

2002-01-01

166

Thermal depoling process and piezoelectric properties of bismuth sodium titanate ceramics  

NASA Astrophysics Data System (ADS)

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

Hiruma, Yuji; Nagata, Hajime; Takenaka, Tadashi

2009-04-01

167

Creation and destruction of morphotropic phase boundaries through electrical poling: a case study of lead-free (Bi(1/2)Na(1/2))TiO3-BaTiO3 piezoelectrics.  

PubMed

We report the first direct evidence that the morphotropic phase boundary in ferroelectric materials, along with the associated strong piezoelectricity, can be created, destroyed, or even replaced by another morphotropic phase boundary through phase transitions during electrical poling. The real-time evolution of crystal structure and domain morphology during the poling-induced phase transitions in (Bi(1/2)Na(1/2))TiO3}BaTiO3 is observed with in situ transmission electron microscopy. These observations elucidate the microstructural origin of the macroscopic piezoelectricity's dependence on the poling field and previously unexplained strain behaviors. This study demonstrates that the ferroelectric-to-ferroelectric transitions during the poling process can completely alter the morphotropic phase boundaries and, hence, must be comprehensively investigated when interpreting the microscopic mechanism of macroscopic piezoelectric behaviors. PMID:23005327

Ma, Cheng; Guo, Hanzheng; Beckman, Scott P; Tan, Xiaoli

2012-09-01

168

Enhanced piezoelectric properties of lead-free 0.935(Bi0.5Na0.5)TiO3-0.065BaTiO3 thin films fabricated by using pulsed laser deposition  

NASA Astrophysics Data System (ADS)

0.935(Bi0.5Na0.5)TiO3-0.065BaTiO3 (BNT-BT) thin films have been grown on Pt(111)/Ti/SiO2/Si substrates by using a pulsed laser deposition method. Deposition conditions of oxygen pressure and deposition temperature were changed. The BNT-BT thin film deposited at 750 C and 300 mTorr exhibited a slim hysteresis loop with a remnant polarization (2 P r ) of 11 C/cm2 and a low leakage current density of 7.3 10-5 A/cm2 at 98 kV/cm. The piezoelectric responses of the thin films were investigated using piezoelectric force microscopy with a lock-in amplifier. The thin films exhibited piezoelectric properties with a d 33, f value of 168 pm/V.

Park, J. S.; Lee, M. H.; Kim, D. J.; Do, D.; Kim, M.-H.; Kim, J. S.; Song, T. K.; Kim, S. W.; Choi, H. I.; Jang, K. W.; Hwang, I. R.; Park, B. H.

2013-04-01

169

Breakthrough: Lead-free Solder  

SciTech Connect

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

Anderson, Iver

2012-01-01

170

Breakthrough: Lead-free Solder  

ScienceCinema

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

Anderson, Iver

2013-03-01

171

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

NASA Astrophysics Data System (ADS)

Polycrystalline sample of lead-free 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 ceramic has been synthesized by solid state reaction method. Single-phase perovskite structure with rhombohedral symmetry was confirmed by x-ray diffraction. Temperature dependent dielectric permittivity studies demonstrated frequency independent behavior, indicating that the studied sample was not a typical relaxor ferroelectric. A polymorphic phase transition between rhombohedral and tetragonal phase was noticed near room temperature followed by a tetragonal to cubic transition with 97 C as the temperature of maximum permittivity. The macroscopic values of d33 and d31 were ~350 pC/N and -141 pm/V, whereas the electromechanical coupling factors kp and kt were 44.5% and 41.6%, respectively. Bulk P-E hysteresis loop was obtained with saturation polarization 11 ?C/cm2 and coercive field ~4 kV/cm. Distinct polarization contrast with a complex mosaic-like domain structure was observed in the out-of-plane mode of piezoresponse force microscopy. The domain width and the correlation length were estimated to be nearly 2 ?m and 827 nm, respectively. Local hysteresis loop with apparent coercive voltage, Vc = 15.8 V, was observed.

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

2013-06-01

172

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

173

Synthesis and electrical properties of SrBi4Ti4O15 piezoelectric ceramics  

NASA Astrophysics Data System (ADS)

Polycrystalline SrBi4Ti4O15 (SBiT) ceramics have been synthesized by a sol-gel method. These ceramics were structurally characterized by powder x-ay diffraction studies (XRD), Rietveld analyses and scanning electron microscopy (SEM). The XRD pattern of SBiT crystallized into an orthorhombic structure with A21 am as space group. The lattice parameters were calculated by Rietveld refinement. SEM images of SBiT show plate-like grains with random orientation of plate faces. Dielectric properties as a function of temperature at different frequencies are reported for this ceramic. Poling experiments were carried out to determine the piezoelectric coefficients. The conductivity of sintered ceramic was studied using impedance spectroscopy. Cole-Cole plots show the presence of two semicircular arcs, suggesting the existence of grain and grain boundary effects.

Mamatha, B.; Suresh, M. B.; James, A. R.; Vithal, M.; Sarah, P.

2011-11-01

174

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

NASA Astrophysics Data System (ADS)

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

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

2002-11-01

175

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

176

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

NASA Astrophysics Data System (ADS)

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

Maurya, Deepam; Zhou, Yuan; Priya, Shashank

2013-03-01

177

Grain oriented growth and properties of ultra-high temperature CaBi 2 Nb 2 O 9 piezoelectric ceramics  

Microsoft Academic Search

CaBi2Nb2O9(CBNO) ceramics was prepared at 1050 C using regular flake-like CBNO powders as the precursor, and synthesized by the molten\\u000a salts synthesis method. The tropism degree and microstructure of the ceramics were analyzed, and the dielectric, ferroelectric\\u000a and piezoelectric properties were characterized. Compared with conventional methods, the properties of CBNO ceramics by the\\u000a new preparation method were found to be

XiaoXia Tian; ShaoBo Qu; BinKe Wang; WuSen Zhang; JianFeng Zhao

178

Variational principles for the equations of porous piezoelectric ceramics.  

PubMed

The governing equations of a porous piezoelectric continuum are presented in variational form, though they were well established in differential form. Hamilton's principle is applied to the motions of a regular region of the continuum, and a three-field variational principle is obtained with some constraint conditions. By removing the constraint conditions that are usually undesirable in computation through an involutory transformation, a unified variational principle is presented for the region with a fixed internal surface of discontinuity. The unified principle leads, as its Euler-Lagrange equations, to all the governing equations of the region, including the jump conditions but excluding the initial conditions. Certain special cases and reciprocal variational principles are recorded, and they are shown to recover some of the earlier ones. PMID:16422425

Altay, Glay; Dkmeci, M Cengiz

2005-11-01

179

New, lead-free solders  

Microsoft Academic Search

Two specific examples of the new lead-free alloys are described. In the Sn-3.5%Ag-l%Zn alloy (m.p.~217C), the eutectic precipitate\\u000a morphology is refined by the relatively small amount of zinc addition and as a result, a high-strength, high-ductility solder\\u000a with significantly improved creep resistance is obtained. As a temperature equivalent drop-in replacement for the Pb-Sn eutectic\\u000a alloy (m.p.~183C), Sn-Zn-In based alloys (m.p.~185C)

M. McCormack; S. Jin

1994-01-01

180

Crystal growth and high piezoelectric performance of 0.95Na0.5Bi0.5TiO3 0.05BaTiO3 lead-free ferroelectric materials  

Microsoft Academic Search

A large single crystal of 0.95Na0.5Bi0.5TiO3-0.05BaTiO3 (0.95NBT-0.05BT) with dimensions of 35 mm diameter 10 mm length was grown by the top-seeded-solution growth method (TSSG). X-ray powder diffraction results indicate that the as-grown 0.95NBT-0.05BT crystal is of a perovskite structure and belongs to the rhombohedral system. The dielectric, ferroelectric and piezoelectric properties were investigated in detail. The room temperature dielectric

Wenwei Ge; Hong Liu; Xiangyong Zhao; Bijun Fang; Xiaobing Li; Feifei Wang; Dan Zhou; Ping Yu; Xiaoming Pan; Di Lin; Haosu Luo

2008-01-01

181

Carbon-Fiber Reinforced Plastic Passive Composite Damper by Use of Piezoelectric Polymer/Ceramic  

NASA Astrophysics Data System (ADS)

In this study, the passive damping of carbon-fiber reinforced plastic (CFRP) cantilever beams is examined using (1) interleaving of viscoelastic thermoplastic films, (2) piezoelectric polymer (PVDF) film interlayers and (3) surface-bonded piezoelectric ceramics. Introducing polyethylene-based film interlayers between composite plies resulted in a significant increase in the vibration loss factor. It is also shown that the vibration damping of CFRP laminates can be improved passively by means of PVDF film interlayers and resistively shunted, surface-bonded piezoelectric ceramic, PbZrO3-PbTiO3 (PZT) sheets. This paper also discusses the enhanced vibration damping of CFRP laminates with dispersed PZT particle interlayers. All these damping methods, interleaving of thermoplastic films, interlayers of PVDF films or dispersed PZT particles between composite plies, and resistively shunted, surface-bonded PZT sheets, can be jointly used to improve the damping of CFRP laminates/structures. The use of CFRP beams in combination with several damping concepts discussed here is promising for application in structures where light weight and improved vibration damping are desired.

Tanimoto, Toshio

2002-11-01

182

Uniform field-induced strain in a/b-axes-oriented Bi3.9Pr0.1Ti3O12 thick films on IrO2/Si substrates for lead-free piezoelectric microdevice applications  

NASA Astrophysics Data System (ADS)

We grew 1.5-?m-thick Bi3.9Pr0.1Ti3O12 (BPT) polycrystalline films with a/b-axes orientation on IrO2/Si substrates from chemical solutions and measured electric-field-induced strain ? by a double-beam laser doppler vibrometer and atomic-force microscopy (AFM). The results reflected uniform film growth and elimination of elastic deformation of the substrate, and the microscopic piezoelectric response in AFM measurements agreed well with the macroscopic response evaluated by laser vibrometer. A large longitudinal ?=0.3% was observed at 400 kV/cm and 10 Hz, and the piezoelectric coefficient d33=d?/dE|0=60 pm/V was calculated. X-ray diffraction analyses revealed that the (200)/(020) peak of BPT was comprised of 40% a domain and led to the reduced values of ferroelectric polarizations of 2Pr=35 and Psat=23 ?C/cm2. This suggests that applying an electric field did not cause fraction reconfiguration of a- and b-domains, and, therefore, the measured large strain was achieved without contribution from the 90-domain-wall motion in a/b-axes-oriented BPT thick films.

Matsuda, Hirofumi; Ito, Sachiko; Iijima, Takashi

2004-08-01

183

Electric and elastic behaviors of a piezoelectric ceramic with a charged surface electrode  

NASA Astrophysics Data System (ADS)

Previous studies on electric and elastic behaviors induced by internal or surface electrodes in a piezoelectric ceramic are mainly concentrated on a two-dimensional analysis. However, most sensors and actuators are related to a three-dimensional piezoelectric body with electrodes. This paper is concerned with the electroelastic analysis of a penny-shaped thin electrode coating on the surface of a hexagonal piezoelectric half-space. The Hankel transform technique is employed to reduce the mixed boundary value problem to an Abel integral equation. Solving the resulting equation analytically, a solution is obtained in a closed form. Explicit expressions for the complete electric and elastic behaviors in any position in the entire piezoelectric half-space are determined in terms of elementary functions. The results indicate that the vertical surface displacement reaches a maximum at the entire electrode region, while the radial surface displacement reaches a peak only at the electrode edge. Moreover, in addition to electric displacement and electric field, elastic stresses exhibit singular behavior near the electrode edge.

Li, Xian-Fang; Lee, Kang Yong

2004-04-01

184

High-power piezoelectric characteristics of manganese-modified BiScO3-PbTiO3 high-temperature piezoelectric ceramics  

NASA Astrophysics Data System (ADS)

Hard piezoelectric ceramics of manganese (Mn)-modified 0.36BiScO3-0.64PbTiO3 (0.36BS-0.64PTM) with a high Curie temperature were prepared using the traditional solid-state reaction method. The effects of different concentrations of Mn on the structure, dielectric and piezoelectric properties of the 0.36BS-0.64PTM ceramics were investigated. X-ray diffraction results indicated that the 0.36BS-0.64PTM ceramics showed a single perovskite structure with tetragonal symmetry and the c/a ratio decreased slightly with increasing Mn content. The grain sizes of the 0.36BS-0.64PTM ceramics were enlarged by Mn addition, and their distributions were uniform. The dielectric loss tan?? decreased clearly with the increase in Mn content, and the mechanical quality factor Qm and vibration velocity v0 were improved significantly at the same time. The Curie temperature Tc, the planar electromechanical coupling factor kp, dielectric loss tan??, mechanical quality factor Qm and vibration velocity v0 of the 0.36BS-0.64PTM ceramics with 3 mol% Mn were about 431 C, 0.57, 0.007, 134 and 1.05 m s-1, respectively. The maximum vibration velocity v0 of the 0.36BS-0.64PTM ceramics is much superior to those of PZT (0.4 m s-1) ceramics and PZT-PZM (0.72 m s-1). These results indicated that the 0.36BS-0.64PTM ceramics are promising candidates for high-temperature and high-power piezoelectric applications.

Chen, Jianguo; Hu, Zhongqiang; Shi, Huaduo; Li, Meiya; Dong, Shuxiang

2012-11-01

185

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

NASA Astrophysics Data System (ADS)

Piezoelectric transducers are often used under compressive stress in smart structure and other applications and it is therefore important to know properties of these materials as a function of applied stress. We have developed an experiment that allows us to find the piezoelectric charge coefficient as a function of uniaxial stress in the poled direction . Both dynamic and static measurements were carried out and the corresponding values of the charge coefficient d33 were obtained as a function of applied stress. These coefficients differ from each other because of the different proportions of reversible and irreversible domain changes that contribute to them and each coefficient can be important in specific applications. Results on a range of PZT ceramics manufactured by EDO Corporation are presented; in general, they show a non- linear behavior with an initial increase in d33 as the stress increases followed by a significant decrease. The time dependence of the measurement has also been investigated.

Yang, G.; Liu, S. F.; Ren, W.; Mukherjee, Binu K.

2000-06-01

186

Highly Efficient Low-frequency Energy Harvester Using Bulk Piezoelectric Ceramics  

NASA Astrophysics Data System (ADS)

This paper describes a new way of manufacturing efficient vibration energy harvesters using thick films of piezoelectrics. The presented fabrication process is based on the thinning of high-density bulk Lead Zirconate Titanate (PZT) ceramic substrates, which enables the realization of thick layers (10-100 ?m). Using this fabrication approach, we prepared two types of cantilever-based vibration energy scavengers (unimorph and bimorph) operating at very low frequency (~15 Hz) with a 50 ?m PZT final thickness. Given that under a harmonic 10 mg vibration the harvested mean power was 1.3 ?W and 3 ?W respectively, these devices rank among the best ever-reported vibration energy scavengers according to commonly accepted figures of merit. The presented fabrication approach is therefore believed to be a good candidate for the manufacturing of highly efficient piezoelectric energy scavengers operating at very low frequency.

Colin, M.; Basrour, S.; Rufer, L.; Bantignies, C.; Nguyen-Dinh, A.

2013-12-01

187

Design and characterization of a carbon-nanotube-reinforced adhesive coating for piezoelectric ceramic discs  

NASA Astrophysics Data System (ADS)

The silver paste electrode of piezoelectric (PZT) ceramic discs has been shown to produce a weak interface bond between a bare PZT and its paste coating under a peeling force. In this work, an investigation was conducted to reinforce the bond with a high density array of oriented carbon nanotube nano-electrodes (CNTs-NEA), between a bare PZT ceramic and a metal substrate. The ensuing design and fabrication of a carbon-nanotube-coated piezoelectric disc (CPZT) is presented along with a study of the bondline integrity of a CPZT mounted on a hosting structure. The CPZT has its electrode silver paste coating replaced with a high density array of CNTs-NEA. Mechanical tests were performed to characterize the shear strength of the bondline between CPZT discs and the substrate. The test results were compared with shear strengths of the bondlines made of pure non-conductive adhesive and adhesive with randomly mixed CNTs. The comparison showed the oriented CNT coating on PZTs could significantly enhance the interfacial shear strength. Through the microscopic examination, it was evident that the ratio between the CNT length (Lc) and the bond thickness (H) significantly influenced the bond strength of CPZT discs. Three major interface microstructure types and their corresponding failure modes for specific Lc/H values were identified. The study also showed that failure did not occur along the interface between the PZT ceramic element and the CNT coating.

Lanzara, G.; Chang, F.-K.

2009-12-01

188

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.~217C), 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.~183C), Sn-Zn-In based alloys (m.p.~185C) 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

189

Fabrication and characterization of potassiumsodium niobate piezoelectric ceramics by spark-plasma-sintering method  

Microsoft Academic Search

High density (Na1?xKx)NbO3 (x = 0.5, 0.6, and 0.7) ceramics were successfully prepared by spark-plasma-sintering (SPS) method. The dielectric and piezoelectric properties of the SPS samples were investigated and compared to that of hot-pressed samples. It is found that, the SPS-sintered (Na1?xKx)NbO3 samples show higher room temperature dielectric constant, higher coercive fields, lower remnant polarizations and lower electromechanical coefficients than

Ruiping Wang; Rongjun Xie; Tadashi Sekiya; Yoshiro Shimojo

2004-01-01

190

Incident-angle dependence of the phase conjugate reflectivity by nonlinear piezoelectric interaction in PZT ceramics.  

PubMed

The reflectivity of an acoustic phase conjugator by nonlinear piezoelectric interaction in PZT ceramics was measured as a function of the incident angle. The phase conjugator was designed as a solid block with a flat surface for the acoustic incidence from water. The phase conjugate reflectivity showed incident angle dependence, which is mainly determined by the transmissivity of the acoustic waves, together with some effects of anisotropy. The field-reconstructing ability of this phase conjugator was simulated for focused incident beams. PMID:11775657

Ohno, M; Tittmann, B R; Kokubo, A; Takagi, K

2001-10-01

191

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.

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

2013-01-01

192

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

193

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

194

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.

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

2012-01-01

195

Piezoelectric and dielectric properties of (Na0.44K0.52)Nb0.84O3-Li0.04(Sb0.06Ta0.1)O3 ceramics with sintering temperature  

NASA Astrophysics Data System (ADS)

Lead-free (Na0.44K0.52)Nb0.84O3-Li0.04(Sb0.06Ta0.1)O3 (NKN-LST) ceramics were fabricated by the conventional mixed oxide method at various sintering temperatures. The results indicate that the sintering temperature significantly influences the sinterbility, microstructure, phase transition, and electrical properties of the NKNLST ceramics. For the NKN-LST ceramics sintered at 1060C to 1100C, the bulk density increased with increasing sintering temperature and showed a maximum value at a sintering temperature of 1080C. The Curie temperature of the NKN-LST ceramics slightly decreased with increasing sintering temperature. The dielectric constant, piezoelectric constant, and electromechanical coupling factor increased with increasing sintering temperature, which might be due to the increase in density. However, a high d33 of 175 ?C/N, k p of 39.3%, and ? of 4614 were obtained for the NKN-LST ceramics sintered at 1080C for 4 h.

Lee, Seung-Hwan; Lee, Young-Hie

2011-09-01

196

Lead-free electric matches.  

SciTech Connect

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

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

2002-01-01

197

The effect of composition on microstructure and properties of PNWPMSPZT ceramics for high-power piezoelectric transformer  

Microsoft Academic Search

(Pb0.95Sr0.05)[(Mn1\\/3Sb2\\/3)x(Ni1\\/2W1\\/2)y(Zr1\\/2Ti1\\/2)z]O3 piezoelectric ceramics (abbreviated as PNWPMSPZT) with 1mol% excess PbO, 0.25wt% CeO2 and 0.2wt% MnO2were synthesized by traditional ceramics process. The effect of Pb(Mn1\\/3Sb2\\/3)O3 (abbreviated as PMS) and Pb(Ni1\\/2W1\\/2)O3 (abbreviated as PNW) on phase structure, dielectric and piezoelectric properties was investigated in detail. The content of perovskite phase of all ceramics specimens is 100%, the phase structure of PNWPMSPZT ceramics

Hong-liang Du; Shao-bo Qu; Jun Che; Zhi-yi Liu; Xiao-yong Wei; Zhi-bin Pei

2005-01-01

198

Combined effects of Li content and sintering temperature on polymorphic phase boundary and electrical properties of Li/Ta co-doped (Na, K)NbO3 lead-free piezoceramics  

NASA Astrophysics Data System (ADS)

Crystallographic structure, phase transition and electrical properties of lead-free (Na0.535K0.485)1- x Li x (Nb0.942Ta0.058)O3 ( x=0.042-0.098) (NKL x NT) piezoelectric ceramics were investigated. The experimental results show that both Li content and sintering temperature strongly affect the orthorhombic-tetragonal polymorphic phase boundary (PPB), which results in remarkable differences of the piezoelectric property and its temperature stability in the NKL x NT ceramics. Chemical analysis indicates that sodium volatilizes more seriously than potassium and lithium with increasing sintering temperature. Due to the comprehensively optimized effects of Li content and sintering temperature, an enhanced piezoelectric constant d 33 (276 pC/N) was obtained at room temperature in the ceramics with x=0.074 sintered at 1000C. In the same composition, a further high d 33 up to 354 pC/N was obtained at 43C, which is close to its T o-t temperature. Furthermore, better temperature stability can be obtained when x=0.082 sintered at 1000C, whose piezoelectric constant d 33 (236 pC/N) keeps almost constant from room temperature to 100C. Such a temperature-independent piezoelectric property is available in the NKL x NT ceramics with high Li content because its T o-t was moved below room temperature.

Shen, Zong-Yang; Wang, Ke; Li, Jing-Feng

2009-12-01

199

Influence of particle size on the sintering behavior and high-power piezoelectric properties of PMnNPZT ceramics  

Microsoft Academic Search

The sintering behaviors and high-power piezoelectric properties of four kinds of powders of Pb(Mn1\\/3Nb2\\/3)O3Pb(Ti,Zr)O3 (PMnNPZT) ceramics have been investigated. These powders are derived from ball milling and stirring milling, respectively. The results reveal that long time milling shrinks the powder particle size distributions and tends to decrease the sintering temperatures of the ceramic. The high-power properties of the ceramics are

Baoshan Li; Guorong Li; WangZhong Zhang; AiLi Ding

2005-01-01

200

Fabrication and properties of PYNPMNPZT quaternary piezoelectric ceramics for high-power, high-temperature applications  

Microsoft Academic Search

xPb(Yb1\\/2Nb1\\/2)O30.05Pb(Mn1\\/3Nb2\\/3)O3(0.95x)Pb(Zr0.48Ti0.52)O3 (PYNPMNPZT) quaternary piezoelectric ceramics were prepared by a traditional ceramics process. The effects of Pb(Yb1\\/2Nb1\\/2)O3 (PYN) content on the phase structure, electrical properties and Curie temperature of the quaternary system were investigated in detail. The phase structure of PYNPMNPZT ceramics changed from tetragonal to rhombohedral with increasing PYN content. The piezoelectric coefficient (d33), the electromechanical coupling factor (Kp) and

Haiyan Chen; Chunhua Fan

2010-01-01

201

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

PubMed

A technique was developed for the solder attachment of coaxial cable leads to 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 mum Cu/1.5 mum Ni/1.0 mum Sn deposited on the thick-film layer improved the strength of the solder joints by eliminating the adsorption 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 nonprecious metal films and the batch processing capabilities of the electron beam deposition technique. PMID:18263219

Vianco, P T

1993-01-01

202

Lead-Free Solder Joint Reliability  

Microsoft Academic Search

Lead-free solder joint reliability is a multi-faceted and challenging topic. Lead-free solders such as eutectic SnAg and SnBi\\u000a have been used successfully in niche applications for many years. With the advent of no-lead (Pb) legislation, a multitude\\u000a of soldering alloys has been proposed for mainstream electronic applications. The high number of lead-free alloy options remains\\u000a a major factor slowing the

Jean-Paul Clech

203

The effect of high energy mechanochemical processing on the microstructure, piezoelectric, ferroelectric and mechanical properties of PLZT ceramics  

NASA Astrophysics Data System (ADS)

Lead lanthanum zirconate titanate (PLZT) ceramics were synthesized using a high energy mechanochemical processing technique, using tungsten carbide grinding vials and balls. The ceramic powders were prepared using the constituent oxide powders, which were subjected to high energy milling, without the use of any excess PbO in the starting composition. TEM studies revealed the formation of very fine particles of the order of 30 nm, due to the milling effect. Highly dense ceramics could be prepared via sintering which resulted in ultra-high strains in these piezoelectric samples of up to 0.25%, a value which has not been reported hitherto by any other known process. The effect of the reduction in particle size on the microstructure, mechanical and electrical properties of PLZT ceramics were studied and are discussed herein.

James, A. R.; Rao, B. S. S. Chandra; Pathak, Mohan; Kamat, S. V.; Subrahmanyam, J.

2008-05-01

204

The effect of high energy mechanochemical processing on the microstructure, piezoelectric, ferroelectric and mechanical properties of PLZT ceramics.  

PubMed

Lead lanthanum zirconate titanate (PLZT) ceramics were synthesized using a high energy mechanochemical processing technique, using tungsten carbide grinding vials and balls. The ceramic powders were prepared using the constituent oxide powders, which were subjected to high energy milling, without the use of any excess PbO in the starting composition. TEM studies revealed the formation of very fine particles of the order of 30nm, due to the milling effect. Highly dense ceramics could be prepared via sintering which resulted in ultra-high strains in these piezoelectric samples of up to 0.25%, a value which has not been reported hitherto by any other known process. The effect of the reduction in particle size on the microstructure, mechanical and electrical properties of PLZT ceramics were studied and are discussed herein. PMID:21825708

James, A R; Chandra Rao, B S S; Pathak, Mohan; Kamat, S V; Subrahmanyam, J

2008-05-14

205

Mechanical, Dynamic Mechanical and Electrical Properties of Conductive Carbon Black\\/Piezoelectric Ceramic\\/Chlorobutyl Rubber Composites  

Microsoft Academic Search

The composites based on conductive carbon black (CCB) and piezoelectric ceramic particles, PMN, and chlorobutyl rubber (CCB\\/PMN\\/IIR) were prepared by compounding and vulcanizing process. Microstructure, mechanical, dynamic mechanical and electrical properties of CCB\\/PMN\\/IIR with various CCB and PMN loading were measured by SEM, mechanical tests, and electrical analysis. The results show tensile properties decrease with increasing PMN loading, while showed

Yanbing Wang; Hao Yan; Zhixiong Huang; Tao Zhang

2012-01-01

206

Novel lead-free solder replacement.  

National Technical Information Service (NTIS)

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 ''drop in'' replacement for common t...

N. C. Lee J. A. Slattery J. R. Sovinsky I. Artaki P. T. Vianco

1994-01-01

207

Lead-Free Small Arms Ammunition Study.  

National Technical Information Service (NTIS)

Report provides cursory environmental, safety, and environmental health impact assessment of switching U.S.A.F. small arms ammunition to lead free bullets and/or primers. Areas covered include hazard identification, toxicity, noise, exposure consideration...

D. Kirsch

1999-01-01

208

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

209

New lead-free solder alloy  

Microsoft Academic Search

As the electronics industry is moving towards lead-free manufacturing processes, a new lead-free solder alloy based on Sn9Zn1Bi2CuIn is described. The quaternary alloy with indium additions exhibits melting, wetting, and mechanical properties superior to those in binary, ternary, and quaternary alloys. Indium as a penternary addition decreases the melting point of this alloy to 181C which it is a lower

Mustafa Kamal; M. S. Meikhail; Abu Bakr El-Bediwi; El-Said Gouda

2005-01-01

210

New lead-free solder alloy  

Microsoft Academic Search

As the electronics industry is moving towards lead-free manufacturing processes, a new lead-free solder alloy based on Sn-9Zn-1Bi-2Cu-In is described. The quaternary alloy with indium additions exhibits melting, wetting, and mechanical properties superior to those in binary, ternary, and quaternary alloys. Indium as a penternary addition decreases the melting point of this alloy to 181 degrees C which it is

M. Kamal; M. S. Meikhail; A. B. El-Bediwi; E. S. Gouda

2005-01-01

211

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

NASA Astrophysics Data System (ADS)

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

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

2013-07-01

212

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

NASA Astrophysics Data System (ADS)

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

Duan, Yuan-Feng; Wing Or, Siu

2011-08-01

213

Compression of PZT-5H piezoelectric ceramic at constant electric field: investigation of energy absorption mechanism  

NASA Astrophysics Data System (ADS)

This paper presents an experimental and analytical investigation into the mechanical behavior of PZT-5H piezoelectric ceramic. The materia is subjected to cyclic uniaxial compressive stress at a constant electric field bias. The damping characteristics such as fraction of energy absorbed and elastic modulus are evaluated as a function of bias electric field. Increasing the positive electric field increases the specific damping and decreases the elastic modulus. The trend is reversed when the electric field becomes sufficiently high to inhibit the domain wall motion by the mechanical stresses. Measured specific damping values vary form 0.18 to 0.46 depending on the stress amplitude and bias electric field. The corresponding secant modulus varies from 79 to 24 Gpz. The optimum electric field values increase as the stress amplitude increases because the positive electric field and the compressive stress counteract each other in terms of domain wall motion. An analytical model shows that the material's response is proportional to the volume fraction of the domains available for switching and the domain wall pressure difference between positive electric field and compressive stress.

Chaplya, Pavel M.; Carman, Gregory P.

2002-07-01

214

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

215

A novel lead-free solder replacement  

SciTech Connect

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 ``drop in`` replacement for common tin/lead eutectic solder. The physical and mechanical properties of this solder are discussed in comparison to tin/lead eutectic solder. The performance of this solder when used for electronics assembly is discussed and compared to other common solders. Fatigue testing results are reported for thermal cycling electronics assemblies soldered with this lead-free composition. The paper concludes with a discussion on indium metal availability, supply and price.

Lee, Ning-Cheng; Slattery, J.A.; Sovinsky, J.R. [Indium Corporation of America, Utica, NY (United States); Artaki, I. [AT and T Bell Labs., Princeton, NJ (United States); Vianco, P.T. [Sandia National Labs., Albuquerque, NM (United States)

1994-06-01

216

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

NASA Astrophysics Data System (ADS)

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

Herabut, Aree

1997-11-01

217

Effects of rare earth metal substituents on the high power piezoelectric properties in lead zirconate titanate-lead (antimony,manganese)O(3) ceramics  

Microsoft Academic Search

Improved piezoelectric materials with higher vibrational velocities are needed to meet the demands of advanced high power electromechanical applications. In this thesis, the effects of the rare earth (RE) metal substituents on the vibrational velocity, the piezoelectric properties and polarization behavior of Pb(Zr,Ti)O3-Pb(Sb,Mn)O3 ceramics have been investigated. Under high drive levels, the mechanical quality factor and the vibrational velocity were

Yongkang Gao

2003-01-01

218

The A-site Li+ driven orthorhombic-tetragonal ferroelectric phase transition and evolving local structures in (Na,K)(Nb,Sb)O3-LiTaO3 lead-free ceramics  

NASA Astrophysics Data System (ADS)

Synchrotron x-ray diffraction and absorption fine structure and Raman spectra on (Na,K)(Nb,Sb)O3-LiTaO3 ceramics suggested that the compositionally induced orthorhombic to tetragonal (O-T) ferroelectric phase transition is dominantly driven by A-site Li+ ions with a large [001] off centering, while B-site Nb atoms are only localized near their average positions of the NbO6 octahedra between O and T phases. The Nb-O octahedra distort over the phase transition by adjusting their positions and orientations. The continuous change of lattice constants bo and at across the phase boundary would facilitate the O-T phase transition through a jump of polar axis from pseudocubic [101] to [001].

Fu, Jian; Zuo, Ruzhong

2013-03-01

219

New Potassium-Sodium Niobate Ceramics with a Giant d33.  

PubMed

For potassium-sodium niobate, poor piezoelectric properties always perplex most researchers, and then it becomes important to attain a giant piezoelectricity. Here we reported a giant piezoelectric constant in (1 - x)(K0.48Na0.52)(Nb0.95Sb0.05)O3-xBi0.5Ag0.5ZrO3 lead-free ceramics. The rhombohedral-tetragonal phase boundary was shown in the ceramics with 0.04 < x ? 0.05, and then the ceramic with x = 0.0425 possesses a giant d33 of ?490 pC/N. We also discussed the physical mechanisms of enhanced piezoelectricity. As a result, such a research can benefit the sustainable development of (K,Na)NbO3 materials. PMID:24784228

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

2014-05-14

220

A phenomenological model for pre-stressed piezoelectric ceramic stack actuators  

NASA Astrophysics Data System (ADS)

In order to characterize the hysteretic characteristics between the output displacement and applied voltage of pre-stressed piezoelectric ceramic stack actuators (PCSAs), this paper considers that a linear force and a hysteretic force will be generated by a linear extension and a hysteretic extension, respectively, due to the applied voltage to a pre-stressed PCSA and the total force will result in the forced vibration of the single-degree-of-freedom (DOF) system composed of the mass of the pre-stressed PCSA and the equivalent spring and damper of the pre-stressed mechanism, which lets the PCSA be pre-stressed to endure enough tension. On this basis, the phenomenological model to characterize the hysteretic behavior of the pre-stressed PCSA is put forward by using the Bouc-Wen hysteresis operator to model the hysteretic extension. The parameter identification method in a least-squares sense is established by identifying the parameters for the linear and hysteretic components separately with the step and periodic responses of the pre-stressed PCSA, respectively. The performance of the proposed phenomenological model with the corresponding parameter identification method is experimentally verified by the established experimental set-up. The research results show that the phenomenological model for the pre-stressed PCSA with the corresponding parameter identification method can accurately portray the hysteretic characteristics of the pre-stressed PCSA. In addition, the phenomenological model for PCSAs can be deduced from the phenomenological model for pre-stressed PCSAs by removing the terms related to the pre-stressed mechanisms.

Wang, D. H.; Zhu, W.

2011-03-01

221

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

NASA Astrophysics Data System (ADS)

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

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

2012-07-01

222

A novel 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 ``drop in`` replacement for common tin\\/lead eutectic solder. The physical and mechanical properties of this solder are discussed in comparison to tin\\/lead eutectic solder. The performance of this

Ning-Cheng Lee; J. A. Slattery; J. R. Sovinsky; I. Artaki; P. T. Vianco

1994-01-01

223

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

Microsoft Academic Search

Piezoelectric transducers are often used under compressive stress in smart structure and other applications and it is therefore important to know properties of these materials as a function of applied stress. We have developed an experiment that allows us to find the piezoelectric charge coefficient as a function of uniaxial stress in the poled direction . Both dynamic and static

G. Yang; S. F. Liu; W. Ren; Binu K. Mukherjee

2000-01-01

224

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

225

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

226

Solid-state conversion of (Na1/2Bi1/2)TiO3-BaTiO3-(K1/2Na1/2)NbO3 single crystals and their piezoelectric properties  

NASA Astrophysics Data System (ADS)

Piezoelectric ceramic with a composition of (94 - x)(Na1/2Bi1/2)TiO3-6BaTiO3-x(K1/2Na1/2)NbO3 (NBT-BT-xKNN) is a promising lead-free piezoelectric material for actuator applications because of its giant electric-field-induced strains, which are comparable with that of soft Pb(ZrxTi1-x)O3 (PZT) ceramics. Using the solid-state single crystal growth method, we succeeded in fabricating usable single crystals of NBT-BT-3KNN (6 mm 6 mm 8 mm size) with a uniform chemical composition. The room temperature piezoelectric properties of ?001?, ?110?, and ?111? oriented single crystals were measured. Single crystals showed strong anisotropic strain characteristics. In particular, ?001? oriented single crystals had excellent piezoelectric properties with small hysteresis and a high strain of 0.57% at 7 kV/mm. In addition, the fabricated single crystals exhibited a high converse piezoelectric constant, Smax/Emax, of over 1000 pm/V at 4 kV/mm. These values are greater than those reported for any lead-containing and lead-free ceramics and comparable with those of lead-based single crystals. Our investigation demonstrates the solid-state conversion of lead-free single crystals and their practical usability in replacement of lead-based materials.

Park, Ji-Hoon; Lee, Ho-Yong; Kang, Suk-Joong L.

2014-06-01

227

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

228

Synthesis and characterization of Pb(Yb1/2Nb1/2)O3-based high-Curie temperature piezoelectric ceramics  

NASA Astrophysics Data System (ADS)

xPb(Yb1/2Nb1/2)O3-(1 - x)Pb(Zr0.36Ti0.64)O3 (xPYN-(1 - x)PZT) piezoelectric ceramics were prepared by the conventional ceramic processing via a B-site oxide mixing route. The synthesized xPYN-(1 - x)PZT ceramics exhibit majority of perovskite structure with slight content of impurity, which exhibit typical tetragonal structure with slight orthorhombic distortion depending on compositions. All the xPYN-(1 - x)PZT ceramics exhibit high Curie temperature (TC/Tm), higher than 380 C, and their dielectric behavior above TC/Tm can be fitted well by the Curie-Weiss law. The xPYN-(1 - x)PZT ceramics exhibit large resistivity, and excellent ferroelectric and piezoelectric properties, which provide promising for the high-power and high-temperature piezoelectric applications. However, electric energy density of the xPYN-(1 - x)PZT ceramics is small due to their nearly rectangular shape of polarization-electric field (P-E) hysteresis loop and early electric displacement saturation, which is not suitable for high energy and power storage applications.

Zheng, Jianfeng; Chen, Zhihui; Fang, Bijun; Ding, Jianning; Zhao, Xiangyong; Xu, Haiqing; Luo, Haosu

2014-06-01

229

Reduction of the piezoelectric performance in lead-free (1-x)Ba(Zr0.2Ti0.8)O3-x(Ba0.7Ca0.3)TiO3 piezoceramics under uniaxial compressive stress  

NASA Astrophysics Data System (ADS)

The effect of a uniaxial compressive stress on the properties of BZT-BCT samples across the morphotropic phase boundary (MPB) is investigated using direct piezoelectric coefficient measurements. In contrast to many lead zirconate titanate compositions, the piezoelectric coefficient decreases monotonically with increasing stress and does not show an initial increase or plateau. Electrically softer rhombohedral and MPB compositions are found to be more susceptible to a decrease in piezoelectric coefficient under an increasing pre-stress than tetragonal compositions. Depoling due to ferroelastic domain switching alone, as observed by x-ray diffraction, does not explain this reduction, but instead a decreasing domain wall density is proposed to be responsible for reduced piezoelectric coefficients under increasing compressive stress. The relaxation of the piezoelectric response after complete unloading supports this proposed mechanism.

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

2012-12-01

230

Dielectric and piezoelectric properties of Bi2O3 added (Pb,Ca,Sr)(Ti,Mn,Sb)O3 ceramics sintered at low temperature  

NASA Astrophysics Data System (ADS)

In this study, in order to develop low temperature sintering ceramics for a thickness mode multilayer piezoelectric transformer, (Pb,Ca,Sr)(Ti,Mn,Sb)O3 ceramics were fabricated using Na2CO3, Li2CO3, MnO2, and Bi2O3 as sintering aids at 870, 900, and 930 C. Their respective dielectric and piezoelectric properties were investigated according to the amount of Bi2O3 addition. At the sintering temperature of 900 C, the optimum value was shown for the density of 6.94 g/cm3, thickness vibration mode electromechanical coupling factor (henceforth, kt) of 0.497, thickness vibration mode mechanical quality factor (henceforth, Qmt) of 3162, and dielectric constant (henceforth, ?r) of 209 for thickness mode multilayer piezoelectric transformer application.

Kim, Dohyung; Yoo, Juhyun; Kim, Insung; Song, Jaesung

2009-03-01

231

Passive Vibration Damping Materials: Piezoelectric Ceramic Composites for Vibration Damping Application.  

National Technical Information Service (NTIS)

Based on the theory and experiments developed in the first year's research work, the use of piezoelectric composites has been explored for application as large area structural composite material with built-in damping. Two parallel efforts have been carrie...

S. Yoshikawa S. K. Kurtz

1992-01-01

232

Electromechanical properties of A-site (LiCe)-modified sodium bismuth titanate (Na{sub 0.5}Bi{sub 4.5}Ti{sub 4}O{sub 15}) piezoelectric ceramics at elevated temperature  

SciTech Connect

The Aurivillius-type bismuth layer-structured (NaBi){sub 0.46}(LiCe){sub 0.04}Bi{sub 4}Ti{sub 4}O{sub 15} (NBT-LiCe) piezoelectric ceramics were synthesized using conventional solid-state processing. Phase analysis was performed by x-ray diffraction and microstructural morphology was assessed by scanning electron microscopy. The dielectric, piezoelectric, ferroelectric, and electromechanical properties of NBT-LiCe ceramics were investigated. The piezoelectric activities were found to be significantly enhanced compared to NBT ceramics, which can be attributed to the lattice distortion and the presence of bismuth vacancies. The dielectric and electromechanical properties of NBT-LiCe ceramics at elevated temperature were investigated in detail. The excellent piezoelectric, dielectric, and electromechanical properties, coupled with high Curie temperature (T{sub c}=660 deg. C), demonstrated that the NBT-LiCe ceramics are the promising candidates for high temperature applications.

Wang Chunming; Wang Jinfeng [School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100 (China); Zhang Shujun; Shrout, Thomas R. [Materials Research Institute, Pennsylvania State University, University Park, Pennsylvania 16802 (United States)

2009-05-01

233

Electromechanical properties of A-site (LiCe)-modified sodium bismuth titanate (Na0.5Bi4.5Ti4O15) piezoelectric ceramics at elevated temperature  

NASA Astrophysics Data System (ADS)

The Aurivillius-type bismuth layer-structured (NaBi)0.46(LiCe)0.04Bi4Ti4O15 (NBT-LiCe) piezoelectric ceramics were synthesized using conventional solid-state processing. Phase analysis was performed by x-ray diffraction and microstructural morphology was assessed by scanning electron microscopy. The dielectric, piezoelectric, ferroelectric, and electromechanical properties of NBT-LiCe ceramics were investigated. The piezoelectric activities were found to be significantly enhanced compared to NBT ceramics, which can be attributed to the lattice distortion and the presence of bismuth vacancies. The dielectric and electromechanical properties of NBT-LiCe ceramics at elevated temperature were investigated in detail. The excellent piezoelectric, dielectric, and electromechanical properties, coupled with high Curie temperature (Tc=660 C), demonstrated that the NBT-LiCe ceramics are the promising candidates for high temperature applications.

Wang, Chun-Ming; Wang, Jin-Feng; Zhang, Shujun; Shrout, Thomas R.

2009-05-01

234

Thermal cycling reliability of lead-free chip resistor solder joints  

Microsoft Academic Search

The solder joint reliability of ceramic chip resistors assembled to laminate substrates has been a long time concern for systems exposed to harsh environments. In this work, the thermal cycling reliability of several 2512 chip resistor lead-free solder joint configurations has been investigated. In an initial study, a comparison has been made between the solder joint reliabilities obtained with components

Jeffrey C. Suhling; H. S. Gale; R. Wayne Johnson; M. Nokibul Islam; Tushar Shete; Pradeep Lall; Michael J. Bozack; John L. Evans; Ping Seto; Tarun Gupta; James R. Thompson

2004-01-01

235

Piezoelectric materials used in underwater acoustic transducers  

Microsoft Academic Search

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

Huidong Li; Zhiqun Deng; Thomas J. Carlson

2012-01-01

236

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

237

Longitudinal piezoelectric coefficient measurement for bulk ceramics and thin films using pneumatic pressure rig  

Microsoft Academic Search

A pneumatic pressure rig was designed to measure the effective d33 coefficient of thin film piezoelectrics by applying a known stress and monitoring the induced charge. It was found that the stress state imposed included components both perpendicular and parallel to the film plane. The later were due to friction and could largely be relieved through sliding of the O-rings

F. Xu; F. Chu; S. Trolier-McKinstry

1999-01-01

238

Constraint-induced crack initiation at electrode edges in piezoelectric ceramics  

Microsoft Academic Search

A strain incompatibility arises between the electrically active and inactive parts of a partially electroded piezoelectric material. This leads to cracking perpendicular to the electrode edge. Symmetric partial electrodes of different widths were applied to lead zirconate titanate (PZT) plates to study the development of these cracks. Different cracking patterns appeared upon application of an electric field, depending on the

S. L dos Santos e Lucato; D. C Lupascu; M Kamlah; J Rdel; C. S Lynch

2001-01-01

239

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

240

A poly vinylidene fluoride (PVF2) piezoelectric film based accelerometer  

Microsoft Academic Search

The paper presents an accelerometer built by means of a piezoelectric film, poly vinylidene fluoride-PVF2. The piezoelectric effect of this is explored and shown to have better mechanical sensitivity than piezoelectric ceramics due to the short thickness of the film. The design is based on a typical piezoelectric ceramic seismic system, which uses the sensitiveness of the piezoelectric element through

R. F. M. Marcal; J. L. Kovaleski; A. A. Suzim

1997-01-01

241

NASA-DoD Lead-Free Electronics Project  

NASA Technical Reports Server (NTRS)

This slide presentation reviews the current state of the lead-free electronics project. It characterizes the test articles, which were built with lead-free solder and lead-free component finishes. The tests performed and reported on are: thermal cycling, combine environments testing, mechanical shock testing, vibration testing and drop testing.

Kessel, Kurt

2010-01-01

242

Electrical properties of lead-free Fe-doped niobium-rich potassium lithium tantalate niobate single crystals  

NASA Astrophysics Data System (ADS)

Lead-free, 0.025 wt% Fe-doped niobium-rich potassium lithium tantalate niobate Fe: K0.95Li0.05Ta1-xNbxO3 single crystals have been grown by the top-seeded melt growth method. All the transition temperatures have been determined by the dielectric constant and loss-dependent temperature. The spontaneous polarizations computed by the integration of pyroelectric coefficients over all the temperatures are consistent with the results of the P-E hysteresis loops. The piezoelectric constants and electromechanical coupling factors are attractive among lead-free piezoelectric materials. With suitable Fe-doping, the electrical properties of KLTN single crystals have been improved overall and can be compared to those of the current important lead-based piezoelectric materials.

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

2013-12-01

243

Properties of Cerium Containing Lead Free Solder  

NASA Astrophysics Data System (ADS)

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

Xie, Huxiao

244

Effects of rare earth metal substituents on the high power piezoelectric properties in lead zirconate titanate-lead (antimony,manganese)O(3) ceramics  

NASA Astrophysics Data System (ADS)

Improved piezoelectric materials with higher vibrational velocities are needed to meet the demands of advanced high power electromechanical applications. In this thesis, the effects of the rare earth (RE) metal substituents on the vibrational velocity, the piezoelectric properties and polarization behavior of Pb(Zr,Ti)O3-Pb(Sb,Mn)O3 ceramics have been investigated. Under high drive levels, the mechanical quality factor and the vibrational velocity were both significantly improved by RE substitution. For a longitudinal vibrator, driven under the d31 mode, root mean square value (rms value) of vibration velocity as high as 0.9 m/s under an electric field of 10 kV/m (rms value) has been found for Yb-substituted specimens, which is 1.5 times higher than that of base Pb(Zr,Ti)O3-Pb(Sb,Mn)O 3 ceramics. For most of rare earth substituents investigated in this system, regardless of the species ionic radii, the piezoelectric properties were observed to have combinative "hard" and "soft" characteristics. "Hard" piezoelectrics have higher Qm values, but lower k31 values. On the other hand, "soft" piezoelectrics have lower Qm values, but higher k31 values. The increased mechanical quality factor Qm (typical of "hard" piezoelectrics) and increased electromechanical coupling coefficient k31 (typical of "soft" ones) were both achieved by RE substitution. With increasing rare earth substituent ionic size, there was no absolute proportional relationship between k31/Qm and dopant ionic size observed. Polarization-electric field (P-E) measurements revealed a significant relaxational polarization similar to a "soft" piezoelectric, in addition to an internal dipolar field similar to a "hard" piezoelectric. A possible explanation for the combinative "hardening" and "softening" effects is the coexistence of randomly quenched and mobile defects. The time dependences after poling of the mechanical quality factor Q m, electromechanical coupling coefficient k31 and dielectric constant K have been investigated for both "soft" and "hard" lead zirconate titanate (PZT) ceramics. A significant increase of Qm with time was observed for "hard" PZTs, however "soft" ones did not exhibit any changes during the same time period. The aging rate after poling was found to be related to the degree of "hard" characteristics. Polarization versus electric field (P-E) measurements of "hard" PZTs revealed the development of a shift of the response along the E axis with time. It is believed that an internal dipolar field develops with time, due to a reorientation of defect dipoles along the direction of spontaneous polarization through oxygen diffusion. (Abstract shortened by UMI.)

Gao, Yongkang

245

HP001: Piezoelectric ceramics for explosively-driven high voltage RF pulse generation  

Microsoft Academic Search

Na0.5Bi0.5TiO3 doped with varying levels of BaTiO3 (BT) was synthesized. Remnant polarization, coercive field, d33, permittivity and grain size were measured. Output voltage generated under fast impact was measured. The piezoelectric doped with 4 mol.% BT generated the highest output voltage and was selected for explosive impact testing. Results showed that it generated an output voltage twice that of the

B. A. Bender; E. P. Gorzkowski; M.-J. Pan

2008-01-01

246

Piezoelectric properties of BiFeO3-PbTiO3 ceramics  

Microsoft Academic Search

Polycrystalline (1-x)BiFeO3-(x)PbTiO3 ceramics (where x=0.2, 0.3 and 0.5) doped with low concentrations of Sb have been produced via a mixed oxide route. Ceramic disks were thinned and electroded and the high electric field resistivity measured at 100 and 150C in order to mimic poling conditions. It was found that the high field resistivity was sensitive to composition in undoped materials,

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

2004-01-01

247

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

248

Synthesis and characterization of lead-free 0.5Ba(Zr{sub 0.2}Ti{sub 0.8})O{sub 3}-0.5(Ba{sub 0.7}Ca{sub 0.3})TiO{sub 3} ceramic  

SciTech Connect

Polycrystalline sample of lead-free 0.5Ba(Zr{sub 0.2}Ti{sub 0.8})O{sub 3}-0.5(Ba{sub 0.7}Ca{sub 0.3})TiO{sub 3} ceramic has been synthesized by solid state reaction method. Single-phase perovskite structure with rhombohedral symmetry was confirmed by x-ray diffraction. Temperature dependent dielectric permittivity studies demonstrated frequency independent behavior, indicating that the studied sample was not a typical relaxor ferroelectric. A polymorphic phase transition between rhombohedral and tetragonal phase was noticed near room temperature followed by a tetragonal to cubic transition with 97 Degree-Sign C as the temperature of maximum permittivity. The macroscopic values of d{sub 33} and d{sub 31} were {approx}350 pC/N and -141 pm/V, whereas the electromechanical coupling factors k{sub p} and k{sub t} were 44.5% and 41.6%, respectively. Bulk P-E hysteresis loop was obtained with saturation polarization 11 {mu}C/cm{sup 2} and coercive field {approx}4 kV/cm. Distinct polarization contrast with a complex mosaic-like domain structure was observed in the out-of-plane mode of piezoresponse force microscopy. The domain width and the correlation length were estimated to be nearly 2 {mu}m and 827 nm, respectively. Local hysteresis loop with apparent coercive voltage, V{sub c} = 15.8 V, was observed.

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

2013-06-07

249

Phase structure and piezoelectric properties of high Curie temperature BiYbO 3PbTiO 3BaTiO 3 ceramics  

Microsoft Academic Search

Perovskite (1?x)(0.1BiYbO30.9PbTiO3)xBaTiO3 (BYPT-BT) ceramics were prepared by the conventional processing. The effect of BaTiO3 on the microstructure and piezoelectric properties was investigated. The results show that the perovskite phase and the Yb2Ti2O7 pyrochlore phase are coexisting in the BYPT-BT ceramics. BaTiO3 influences the lattice structure and Ba2+ will replace A-site ions of perovskite, which decreases the lattice constant ratio c\\/a,

Gao Feng; Hong Rongzi; Liu Jiaji; Li Zhen; Cheng Lihong; Tian Changsheng

2009-01-01

250

Analysis of a bi-piezoelectric ceramic layer with an interfacial crack subjected to anti-plane shear and in-plane electric loading  

Microsoft Academic Search

The behaviour of a bi-piezoelectric ceramic layer with a centre interfacial crack subjected to anti-plane shear and in-plane electric loading has been studied. The dislocation density functions and the Fourier integral transform method have been employed to eliminate the problem of singular integral equations. The normalized energy release rate, stress and electrical displacement intensity factors, G\\/G0,KIII\\/KIII0 and KD\\/KD0, respectively, were

Ai Kah Soh; Dai-Ning Fang; Kwok Lun Lee

2000-01-01

251

Effects of Vibration Stress and Temperature on the Characteristics of Piezoelectric Ceramics under High Vibration Amplitude Levels Measured by Electrical Transient Responses  

Microsoft Academic Search

This paper presents a characteristic evaluation of piezoelectric ceramics at high vibration amplitude levels of resonance, based on the electrical transient response technique. Low-Q and high-Q materials are measured, and the effect of vibration stress is obtained without affecting temperature. It is revealed that for low-Q materials an increase of loss is caused mainly by the vibration stress, while for

Mikio Umeda; Kentaro Nakamura; Sadayuki Ueha

1999-01-01

252

Fabrication of Pb(Nb,Ni)O3Pb(Zr,Ti)O3 Piezoelectric Ceramic Fibers by Extrusion of a Sol-Powder Mixture  

Microsoft Academic Search

A study on the fabrication of Pb(Nb,Ni)O3-Pb(Zr,Ti)O3 (PNN-PZT) piezoelectric ceramic fibers by extrusion of a powder-sol mixture is presented. The process using extrusion of a powder-sol mixture was first applied to the fabrication of PZT fibers and its advantages were discussed in the former study. In this study, the process is applied to the fabrication of PNN-PZT fibers, and the

Jinhao Qiu; Junji Tani; Naoki Yanada; Yoshimasa Kobayashi; Hirofumi Takahashi

2004-01-01

253

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

NASA Astrophysics Data System (ADS)

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

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

2012-04-01

254

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

255

Enhanced piezoelectric performance of (0.98-x)Bi(Sc3/4In1/4)O3-xPbTiO3-0.02Pb(Zn1/3Nb2/3)O3 ternary high temperature piezoelectric ceramics  

NASA Astrophysics Data System (ADS)

(0.98-x)Bi(Sc3/4In1/4)O3-xPbTiO3-0.02Pb(Zn1/3Nb2/3)O3 (BSI-PT-PZN) high temperature piezoelectric ceramics were prepared by traditional solid-state reaction method. Combining X-ray diffraction results with piezoelectric data, it was found that the morphotropic phase boundary (MPB) occurred at x = 0.575. The piezoelectric constant d33, curie temperature Tc, and electromechanical coupling factor kp of BIS-PT-PZN ceramics with MPB composition were 427 pC/N, 412 C, and 0.51, respectively. Furthermore, the strain of BIS-PT-PZN ceramics reached up to 0.25% under the electric field of 40 kV/cm. Temperature-dependent electromechanical coupling coefficient for MPB composition was stable from room temperature up to 350 C. The piezoelectric properties of BIS-PT-PZN ceramics were comparable to that of 0.36BiScO3-0.64PbTiO3 (BS-PT) ceramics, and the piezoelectric constant d33 of BIS-PT-PZN ceramics was about twice that of our previous reported 0.4Bi(Sc3/4In1/4)O3-0.6PbTiO3 (BSI-PT) ceramics. The reduction in the expensive Sc2O3 content and comparable piezoelectric properties with BS-PT ceramics indicated that BIS-PT-PZN ceramics were promising for commercial applications as high temperature actuators and sensors.

Chen, Jianguo; Zhao, Tianlong; Cheng, Jinrong; Dong, Shuxiang

2013-04-01

256

Reliability and Leachate Testing of Lead-Free Solder Joints  

Microsoft Academic Search

A test program was started in 2000 at Boeing for the evaluation of the reliability of lead -free solder joints. One lead-free solder was tested for reflow operations (tin\\/3.8%silver\\/0.7%copper) and one solder was tested for wave soldering operations (tin\\/0.7%copper). Three lead-free circuit board finishes were also tested: immersion silver; electrolytic gold on top of nickel; and an OSP (organic solderability

Thomas A. Woodrow

257

Incorporation of piezoelectric Pb(Zr,Ti)O3 fibers into ceramic/polymer composites  

NASA Astrophysics Data System (ADS)

The processing of Pb(Zr,Ti)O3, or PZT, fiber and fiber/polymer composites for transducer applications is discussed. Green PZT fibers, 80 to 100 micrometers in diameter, were formed at Advanced Cerametrics, Inc., using the Viscous Suspension Spinning Process (VSSP). In this process, fine PZT powder is intimately mixed with polymer precursor by high shear mixing. The powder and precursor mixture is spun through a spinneret into a coagulation bath to form fibers. The fibers are washed, dried, and collected on a spool. Yarns containing between 10 and 500 individual fibers were collimated by applying a polymeric sizing to the yarns, and passing the yarns through sizing dies. Yarn bundle tightness and flexibility were controlled by the sizing chemistry. Continuous green yarns were cut to short lengths, or woven in different architectures to create composites with novel microstructures. The short yarns were fired to product PZT straight rods for `pick and place' piezoelectric composites. The woven structures were heat treated and backfilled with polymer to create composites with 1-3, 2-3, and 3-3 connectivity. After heat treatment, the diameter of the individual PZT fibers was 10 to 20 micrometers . Electromechanical characteristics of a number of composites were determined, and will be reported. The PZT VSSP fibers can be used to form fine-scale, large area piezoelectric fiber/polymer composites for use in hydrophones, transducers for medical ultrasonic imaging and non-destructive evaluation, and as sensors and actuators in vibration and noise control.

Safari, Ahmad; Janas, Victor; Jadidian, Bahram; French, Jonathan D.; Weitz, Gregory E.; Luke, John E.; Cass, Bud

1996-05-01

258

Passive Vibration Damping Materials: Piezoelectric Ceramic Composites for Vibration Damping Applications.  

National Technical Information Service (NTIS)

The study to produce ultra-fine (less than 50 micrometers in diameter) lead zirconate titanate (PZT) ceramic fibers for passive damping application has been carried out under several aspects. Sol-gel chemistry was undertaken to produce stable spinnable so...

S. Yoshikawa

1994-01-01

259

Effect of SHI irradiation on NBT-BT ceramics: Transformation of relaxor ferroelectric to ferroelectric nature  

NASA Astrophysics Data System (ADS)

The lead free NBT-BT ceramics prepared by conventional solid state reaction method were irradiated with 120 MeV Au9+ ions with different fluences. The structural, dielectric and piezoelectric studies were carried out before and after irradiation. The agglomeration and increase of grain size are observed in SEM analysis after the irradiation. The diffuse phase transition disappeared after high fluence of irradiation and the material becomes ferroelectric in nature. The piezoelectric properties were decreased due to the reduced stability of the ferroelectric domains after the irradiation.

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

2013-01-01

260

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

261

Dielectric dispersion of ferroelectric ceramics and single crystals by sound generation in piezoelectric domains  

SciTech Connect

Periodic domain configurations with alternating 180{degree} and 90{degree} domains are not completely mechanically clamped up to microwave frequencies. Above the acoustic resonance of the ferroelectric sample, therefore, the dielectric constant comprises contributions which can be attributed to the free dielectric constant. Up to microwave frequencies the domains are piezoelectrically active; they emit longitudinal and shear thickness waves into the surroundings which cause dielectric loss in the sample. The dielectric step from the free condition to the clamped condition at the relaxation frequency is on the order of {Delta}{var_epsilon} {approx} 10--100. This step is much smaller than the step caused by the emission of shear waves from 90{degree} domain walls.

Arlt, G.; Boettger, U.; Witte, S. [Aachen Univ. of Technology (Germany). Inst. fuer Werkstoffe der Elektrotechnik

1995-04-01

262

Experiments to demonstrate piezoelectric and pyroelectric effects  

NASA Astrophysics Data System (ADS)

Piezoelectric and pyroelectric materials are used in many current applications. The purpose of this paper is to explain the basic properties of pyroelectric and piezoelectric effects and demonstrate them in simple experiments. Pyroelectricity is presented on lead zirconium titanate (PZT) ceramics as an electric charge generated by the temperature change. The direct piezoelectric effect is demonstrated by the electric charge generated from the bending of the piezoelectric ceramic membrane or from the gas igniter. The converse piezoelectric effect is presented in the experiments by the deflection of the bending piezoelectric element (piezoelectric bimorph).

Erhart, Ji?

2013-07-01

263

The ontology based FMEA of lead free soldering process  

Microsoft Academic Search

Paper is directed to improvement of a FMEA (Failure Mode and Effects Analysis) procedure in the area of reflow lead free soldering by the use of an ontology paradigm. Some ontology editor tools suitable for our intention are presented. Particular phases of ontology utilization for development of more exact approach to the FMEA procedure of reflow lead free soldering are

Martin Molhanec; Pavel Mach

2009-01-01

264

NanoComposite Lead-Free Interconnect and Reliability  

Microsoft Academic Search

Lead free solder bumping requirements have challenged researchers to develop new technologies to achieve fine pitch interconnects. ITRS has predicts that by 2017 the industry will require 70 micron pitch area array lead free interconnects for flip chips. This paper describes bumping, assembly and reliability evaluation of a new nano composite 20 micron pitch interconnect technology. Nanoparticles are the most

Ravi Doraiswami; Rao Tummala

2005-01-01

265

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

266

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

PubMed

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

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

2010-02-19

267

NASA-DoD Lead-Free Electronics Project  

NASA Technical Reports Server (NTRS)

In response to concerns about risks from lead-free induced faults to high reliability products, NASA has initiated a multi-year project to provide manufacturers and users with data to clarify the risks of lead-free materials in their products. The project will also be of interest to component manufacturers supplying to high reliability markets. The project was launched in November 2006. The primary technical objective of the project is to undertake comprehensive testing to generate information on failure modes/criteria to better understand the reliability of: (1) Packages (e.g., Thin Small Outline Package [TSOP], Ball Grid Array [BGA], Plastic Dual In-line Package [PDIP]) assembled and reworked with solder interconnects consisting of lead-free alloys (2) Packages (e.g., TSOP, BGA, PDIP) assembled and reworked with solder interconnects consisting of mixed alloys, lead component finish/lead-free solder and lead-free component finish/SnPb solder

Kessel, Kurt

2009-01-01

268

NASA-DoD Lead-Free Electronics Project  

NASA Technical Reports Server (NTRS)

In response to concerns about risks from lead-free induced faults to high reliability products, NASA has initiated a multi-year project to provide manufacturers and users with data to clarify the risks of lead-free materials in their products. The project will also be of interest to component manufacturers supplying to high reliability markets. The project was launched in November 2006. The primary technical objective of the project is to undertake comprehensive testing to generate information on failure modes/criteria to better understand the reliability of: - Packages (e.g., TSOP, BOA, PDIP) assembled and reworked with solder interconnects consisting of lead-free alloys - Packages (e.g., TSOP, BOA, PDIP) assembled and reworked with solder interconnects consisting of mixed alloys, lead component finish/lead-free solder and lead-free component finish/SnPb solder.

Kessel, Kurt R.

2009-01-01

269

NASA-DoD Lead-Free Electronics Project  

NASA Technical Reports Server (NTRS)

In response to concerns about risks from lead-free induced faults to high reliability products, NASA has initiated a multi-year project to provide manufacturers and users with data to clarify the risks of lead-free materials in their products. The project will also be of interest to component manufacturers supplying to high reliability markets. The project was launched in November 2006. The primary technical objective of the project is to undertake comprehensive testing to generate information on failure modes/criteria to better understand the reliability of: - Packages (e.g., TSOP, BGA, PDIP) assembled and reworked with solder interconnects consisting of lead-free alloys - Packages (e.g., TSOP, BGA, PDIP) assembled and reworked with solder interconnects consisting of mixed alloys, lead component finish/lead-free solder and lead-free component finish/SnPb solder.

Kessel, Kurt R.

2009-01-01

270

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

271

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

PubMed

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

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

2011-02-01

272

Thermodynamic and nonstoichiometric behavior of the lead-doped and lead-free Bi-2212 systems  

NASA Astrophysics Data System (ADS)

Electromotive force (EMF) measurements of oxygen fugacities as a function of stoichiometry have been made on lead-doped and lead-free superconducting ceramics in the temperature range ?700-815C by means of an oxygen titration technique. Equations for the variation of oxygen partial pressure with composition and temperature have been derived from our EMF measurements. Thermodynamic assessments of the partial molar quantities ?H(O 2) and ?S(O 2) for lead-doped Bi-2212 and lead-free Bi-2212 indicate that the solid-state decomposition of these bismuth cuprates at low oxygen partial pressure can be represented by the diphasic CuO sbnd Cu 2O system. Comparison of these results with lead-doped Bi-2223 in powder and silver sheath form will be presented.

Tetenbaum, Marvin; Hash, Mark; Tani, Benjamin S.; Luo, Jin S.; Maroni, Victor A.

1997-08-01

273

Development of lead-free solders for hybrid microcircuits  

SciTech Connect

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

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

1996-01-01

274

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

275

Dielectric and piezoelectric properties of SrBi 4- xHo xTi 4O 15 ( x=0.00, 0.02, 0.04 and 0.06) ceramics  

NASA Astrophysics Data System (ADS)

The dielectric and piezoelectric properties of SrBi 4- xHo xTi 4O 15 ( x=0.00, 0.02, 0.04 and 0.06) ceramics were investigated. SrBi 4- xHo xTi 4O 15 ( x=0.00, 0.02, 0.04 and 0.06; SBHT- x) ceramics were synthesized by the conventional solid state reaction sintering method. An X-ray diffraction measurement indicated that a single phase layered perovskite was obtained for all compositions. Studies of dielectric properties with temperature at different frequencies and piezoelectric properties have been carried out.

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

2010-12-01

276

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: (1) Packages (e.g., Thin Small Outline Package [TSOP], Ball Grid Array [BGA], Plastic Dual In-line Package [PDIP]) assembled and reworked with lead-free alloys, (2) Packages (e.g., TSOP, BGA, PDIP) assembled and reworked with mixed (lead/lead-free) alloys.

Kessel, Kurt R.

2009-01-01

277

Lead-free reflow soldering for electronics assembly  

Microsoft Academic Search

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

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

2001-01-01

278

High drop test reliability: lead-free solders  

Microsoft Academic Search

Recently, preventing environmental pollution, lead-free (Pb-free) solders are about to replace tin-lead (Sn-Pb) eutectic solders. Sn-Ag-Cu alloys are leading candidates for lead free solders. Sn-Ag-Cu-P was developed last year, but Sn-Ag-Cu-P alloys were not satisfactory to meet severe customer requirements like thermal aging process followed by drop tests. To improve drop test performance after the thermal aging process, a combination

M. Amagai; Yoshitaka Toyoda; Tsukasa Ohnishi; Satom Akita

2004-01-01

279

High solder joint reliability with lead free solders  

Microsoft Academic Search

Recently. preventing environmental pollutions. lead-free (Pb-free) soldcrs are about to replace tin-lead (Sn-Pbj eutectic solders. Sn-Ag-Cu alloys arc lcading candidatcs for lead free solders. However. Sn-Ag-Cu alloys were not satisfied to meet sever custoiner requirements. At first, optimum silver wt% Solder alloy balls were attached to a 10x10 inm BGA package which consisted or the polyimnide-based substrate: the epoy rnoldiog

Maszuini Amagai; Y. Toyoda; T. Tajima

2003-01-01

280

NASA-DoD Lead-Free Electronics Project  

NASA Technical Reports Server (NTRS)

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

Kessel, Kurt

2010-01-01

281

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

282

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

SciTech Connect

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

Liu Jing; Shen Zhijian; Yan Haixue; Reece, Michael J.; Kan Yanmei; Wang Peiling [Department of Inorganic Chemistry, Arrhenius Laboratory, Stockholm University, S-106 91 Stockholm (Sweden); Department of Materials, Queen Mary University of London, Mile End Road, London E1 4NS (United Kingdom); Shanghai Institute of Ceramics, Chinese Academy of Science, 1295 Dingxi Road, Shanghai 200050 (China)

2007-11-15

283

Thermomechanically loaded lead-free LGA joints in LTCC\\/PWB assemblies  

Microsoft Academic Search

Purpose The purpose of this paper is to investigate the feasibility of using land grid array (LGA) solder joints as a second-level interconnection option in low-temperature co-fired ceramic (LTCC)\\/printed wiring board (PWB) assemblies for telecommunication applications. The characteristic behaviour of two commercial lead-free solder materials (Sn4Ag0.5Cu and Sn3Ag0.5Cu0.5In0.05Ni) in reflow processes and thermal cycling tests are also evaluated. Design\\/methodology\\/approach

Olli Nousiainen; Timo Urhonen; Tero Kangasvieri; Risto Rautioaho; Jouko Vhkangas

2010-01-01

284

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

285

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

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

1994-01-01

286

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

287

Lead-free nanogenerator made from single ZnSnO3 microbelt.  

PubMed

We demonstrated a single-microbelt nanogenerator first made using a ZnSnO(3) microbelt that generated an output power of ?3 nW under a compressive and releasing strain of 0.8-1%. The ZnSnO(3) nanobelts/microbelts were synthesized using a vapor transfer process at 1173 K. The X-ray diffraction pattern shows that the microbelts belong to ZnSnO(3) with rhombohedral structure. An individual ZnSnO(3) microbelt was bonded at its ends on a flexible polystyrene substrate as a nanogenerator, which gives an output voltage and current of 100 mV and 30 nA, respectively, corresponding to an energy conversion efficiency of 4.2-6.6% (based on 0.8-1% strain). Our results show that ZnSnO(3) microbelts are one of the highly promising materials for lead-free piezoelectric energy harvesting. PMID:22482511

Wu, Jyh Ming; Xu, Chen; Zhang, Yan; Wang, Zhong Lin

2012-05-22

288

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

SciTech Connect

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

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

2012-04-15

289

Lead-free flux technology and influence on cleaning  

Microsoft Academic Search

Lead-free flux technology for electronic industry is mainly driven by high soldering temperature, high alloy surface tension, miniaturization, air soldering due to low cost consideration, and environmental concern. Accordingly, the flux features desired included high thermal stability, high resistance against burn-off, high oxidation resistance, high oxygen barrier capability, low surface tension, high fluxing capacity, slow wetting, low moisture pickup, high

Ning-Cheng Lee

2009-01-01

290

Medium Caliber Lead-Free Electric Primer. Version 2.  

National Technical Information Service (NTIS)

Lead Free Electric Primers (LFEP) based on energetic nanocomposites were examined as a replacement for conventional lead styphnate primers. On small scale samples, outstanding all-up round action times (AUR-ATs) were obtained for ambient (2.92 ms) and at ...

E. Gogley K. T. Higa T. Foley

2012-01-01

291

Prospect of Lead Free Alternatives for Reflow Soldering  

Microsoft Academic Search

The prospects of 10 major lead-free solder alloys for being widely used for reflow soldering are studied in this work. Compatibility of those alloys with a variety of representative flux chemistries is considered essential, and is determined for performance in handling - ability, including shelf life and tack time, and soldering capability, including solder balling, wetting, and solder joint appearance.

Ning-Cheng Lee; Benlih Huang

1999-01-01

292

Evaluation of Lead- Free Solder Joints in Electronic Assemblies  

NASA Astrophysics Data System (ADS)

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

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

1994-08-01

293

Evaluation of lead-free solder joints in electronic assemblies  

SciTech Connect

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

Artaki, I.; Jackson, A.M. [AT& T Bell Lab., Princeton, NJ (United States); Vianco, P.T. [Sandia National Lab., Albuquerque, NM (United States)

1994-08-01

294

Cymbal piezoelectric composite underwater acoustic transducer  

Microsoft Academic Search

The working principle of Cymbal piezoelectric composite underwater acoustic transducer was studied in this paper. PZT-5A piezoelectric ceramic disk was used as piezoelectric phase and brass foil was used as end cap electrode of the Cymbal transducer. The silicon rubber was used as the insulated proof layer of the underwater acoustic transducer. The properties of this transducer used as hydrophone,

Denghua Li; Min Wu; Peixi Oyang; Xiaofei Xu

2006-01-01

295

Enhanced piezoelectric properties of (Na0.5+y+zK0.5-y)(Nb1-xTax)O3 ceramics  

NASA Astrophysics Data System (ADS)

A- and B-site ratios in (Na0.5+y+zK0.5-y)(Nb1-xTax)O3 ceramics with ABO3 structure were investigated to differentiate the effects of polymorphic phase transition (PPT), morphotropic phase boundary (MPB), and Na nonstoichiometry on piezoelectric coefficient (d33). MPB was intrinsically determined by the ratio between Na and K, whereas PPT was extrinsically controlled by Ta substitution. PPT temperature between orthorhombic and tetragonal phases (TO-T) was reduced to room temperature at x = 0.45. d33 was increased to 310 pC/N at y = 0.03 and z = 0 by the combined effects of PPT and MPB and was further enhanced to 333 pC/N by the Na nonstoichiometry at z = 0.015 with improved density.

Sung, Y. S.; Baik, S.; Lee, J. H.; Ryu, G. H.; Do, D.; Song, T. K.; Kim, M. H.; Kim, W. J.

2012-07-01

296

Research on High Power Transducer Ceramics. Stress Sensitivity of Piezoelectric Ceramics: Part One: Sensitivity to Compressive Stress Parallel to the Polar Axis.  

National Technical Information Service (NTIS)

Measurements of changes in permittivity, tan delta and D33 as function of compressive stress parallel to the polar axis are presented for lead zirconate-lead titanate transducer ceramics. The hard ceramics (PZT-4 and PZT-8) suitable for high power applica...

H. H. A. Krueger

1967-01-01

297

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

298

TMA, DMA, DSC, and TGA of lead free solders  

Microsoft Academic Search

Most of the electronics packaging materials, especially solders are temperature dependent. Their temperature-dependent material properties can be obtained by TMA (thermal mechanical analysis), DMA (dynamic mechanical analysis), DSC (differential scanning calorimeter), and TGA (thermogravimetric analysis). In this study, the thermal coefficient of expansion (TCE), storage modulus, moisture uptake, and melting point of two lead free solders, 96.5wt%Sn-3.5wt%Ag and 42wt%Sn-58wt%Bi provided

John H. Lau; Chris Chang

1998-01-01

299

TMA, DMA, DSC and TGA of lead free solders  

Microsoft Academic Search

Most of the electronics packaging materials, especially solders, are temperature dependent. Their temperature-dependent material properties can be obtained by TMA (thermal mechanical analysis), DMA (dynamic mechanical analysis), DSC (differential scanning calorimetry), and TGA (thermogravimetric analysis). In this study, the thermal coefficient of expansion (TCE), storage modulus, moisture uptake, and melting point of two lead free solders, 96.5wt%Sn-3.5wt%Ag and 42wt%Sn-58wt%Bi provided

John H. Lau; Chris Chang

1999-01-01

300

Lead-Free Solders in IC Manufacture: A Review  

Microsoft Academic Search

The compositions and melting points of lead-free solders suitable for IC packaging are given. The use of tinbismuth alloys for both this purpose and the corrosion protection of packages is outlined. An investigation is described into the dissolution of 0.04-mm-thick gold wire in the POIn50 tinindium solder in the molten or solid state. In the former case the process is

V. V. Zenin; V. N. Belyaev; Yu. E. Segal; A. A. Kolbenkov

2003-01-01

301

Advanced alloy for lead-free solder balls  

Microsoft Academic Search

A new alloy for lead-free solder balls is introduced combining the advantages of a smooth surface after production and a uniform reflectivity after the ball attach process. This property significantly simplifies the inspection process during ball grid array (BGA) processing. By adding small amounts of Indium and Lanthanum to the ternary eutectic SnAgCu-alloy a pentary, virtually eutectic composition with a

Marc Dittes; Hermann Walter

2003-01-01

302

Characterization of lead-free solders for electronic packaging  

NASA Astrophysics Data System (ADS)

The characterization of lead-free solders, especially after isothermal aging, is very important in order to accurately predict the reliability of solder joints. However, due to lack of experimental testing standards and the high homologous temperature of solder alloys (Th > 0.5T m even at room temperature), there are very large discrepancies in both the tensile and creep properties provided in current databases for both lead-free and Sn-Pb solder alloys. In this research, mechanical measurements of isothermal aging effects and the resulting changes in the materials behavior of lead-free solders were performed. A novel specimen preparation procedure was developed where the solder uniaxial test specimens are formed in high precision rectangular cross-section glass tubes using a vacuum suction process. Using specimens fabricated with the developed procedure, isothermal aging effects and viscoplastic material behavior evolution have been characterized for 95.5Sn-4.0Ag-0.5Cu (SAC405) and 96.5Sn-3.0Ag-0.5Cu (SAC305) lead-free solders, which are commonly used as the solder ball alloy in lead-free BGAs and other components. Analogous tests were performed with 63Sn-37Pb eutectic solder samples for comparison purposes. Up to 40% reduction in tensile strength was observed for water quenched specimens after two months of aging at room temperature. Creep deformation also increased dramatically with increasing aging durations. Microstructural changes during room temperature aging were also observed and recorded for the solder alloys and correlated with the observed mechanical behavior changes. Aging effects at elevated temperatures for up to 6 months were also investigated. Thermal aging caused significant tensile strength loss and deterioration of creep deformation. The thermal aging results also showed that after an initial tensile strength drop, the Sn-Pb eutectic solder reached a relatively stable stage after 200 hours of aging. However, for SAC alloy, both the tensile and creep properties continuously changed with increasing aging time. The creep resistance of SAC alloy was lower than that of Sn-Pb at longer aging durations at elevated temperature. Solder alloys are extremely sensitive to changes in both temperature and strain rate. A linear relationship was found between the temperature and the tensile properties, while a power law relationship was found between strain rate and tensile properties. Constitutive models have also been developed with multiple variables of strain rate and temperature. Creep testing was conducted at different stress levels and temperatures to explore the constitutive modeling. SAC alloy was found to have higher creep resistance and activation energy than the Sn-Pb solder without thermal aging.

Ma, Hongtao

303

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

SciTech Connect

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

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

2012-11-15

304

Properties of Lead-Free Piezoceramics Based on Alkali Niobates  

Microsoft Academic Search

The market for piezoceramic components is dominated by lead zirconate titanate (PZT) materials containing more than 60 wt% lead. Since lead is a toxic heavy metal, it has become a great concern how to eliminate the use of PZT by replacing it by non-harmful materials while maintaining comparable piezoelectric properties. This was the objective of the European LEAF project within

Erling Ringgaard; Thom Wurlitzer; Wanda W. Wolny

2005-01-01

305

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

306

Active piezoelectric diaphragms  

NASA Astrophysics Data System (ADS)

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, rather than the expected in-plane direction. Unlike other out of plane piezoelectric actuators, which are benders, these Radial Field Diaphragms 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., Jr.; Covington, Ed W., III

2002-07-01

307

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

308

Engineering of fine structured 2-2 and 2-0-2 piezoelectric ceramic\\/polymer composites by tape casting  

Microsoft Academic Search

A novel process of forming piezoelectric composites using tape cast sheets is reported. Composites with 2-2 and 2-0-2 connectivity were formed using sintered tape cast sheets of PZT-5H. The third phase in the form of powder included zirconia, alumina, or hollow and solid glass spheres. Electromechanical properties including d33, dh , K, ringdown time, and kt were evaluated. The 2-0-2

R. P. Schaeffer; V. F. Janas; A. Safari

1996-01-01

309

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 AgCuNiSn and AgInPdSn 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

310

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

311

Domain Reorientation Effects on the Temperature Dependence of Piezoelectric Properties in Pb(Zn1\\/3Nb2\\/3)O3-PbTiO3-PbZrO3 Ceramics  

Microsoft Academic Search

For the PZN-PT-PZ ceramic system, the difference in the temperature characteristics of piezoelectric properties between the tetragonal phase and the rhombohedral one was studied from the viewpoint of a domain reorientation mechanism. From the measurement of thermal expansion and the change of high-temperature X-ray diffraction patterns for two phases, it is considered that the more stable temperature characteristics of the

Sung-Kwon Wi; Ho-Gi Kim

1992-01-01

312

Pb(Zn(1/3)Nb(2/3))O3-based piezoelectric and electrostrictive ceramics  

NASA Astrophysics Data System (ADS)

Ceramics based on Pb(Zn(1/3)Nb(2/3))O3 (PZN) with perovskite structure were prepared by a modification of La(Ni(1/2)Ti(1/2))O3 (LNT) or La(Co(1/2)Ti(1/2))O3 (LCT), and the effects of the suppression of the pyrochlore phase on the dielectric and electrostrictive properties were investigated. Results showed that PZN-based ceramics with LNT or LCT modification are suitable for use as electrostrictive materials with little hysteresis and adequate temperature stability in the vicinity of room temperature.

Kanegae, Toshio; Sakata, Koichiro; Takenaka, Tadashi

1991-09-01

313

Oxygen stoichiometry, phase stability, and thermodynamic behavior of the lead-doped and lead-free Bi-2212 systems.  

SciTech Connect

Electromotive-force (EMF) measurements of oxygen fugacities as a function of stoichiometry have been made on lead-doped and lead-free Bi{sub 2-z}Pb{sub z}Sr{sub 2}Ca{sub 1}Cu{sub 2}O{sub x} superconducting ceramics in the temperature range {approx} 700-815 C by means of an oxygen-titration technique that employs an yttria-stabilized zirconia electrolyte. Equations for the variation of oxygen partial pressure with composition and temperature have been derived from our EMF measurements. Thermodynamic assessments of the partial molar quantities {Delta}{bar H} (O{sub 2}) and {Delta}{bar S}(O{sub 2}) for lead-doped Bi-2212 and lead-free Bi-2212 indicate that the solid-state decomposition of these bismuth cuprates at low oxygen partial pressure can be represented by the diphasic CuO---Cu{sub 2}O system.

Tetenbaum, M.; Hash, M.; Tani, B. S.; Maroni, V. A.; Chemical Engineering

1996-01-01

314

Oxygen stoichiometry, phase stability, and thermodynamic behavior of the lead-doped and lead-free Bi-2212 systems  

NASA Astrophysics Data System (ADS)

Electromotive-force (EMF) measurements of oxygen fugacities as a function of stoichiometry have been made on lead-doped and lead-free Bi 2- zPb zSr 2Ca 1Cu 2O x superconducting ceramics in the temperature range ? 700-815C by means of an oxygen-titration techique that employs an yttria-stabilized zirconia electrolyte. Equations for the variation of oxygen partial pressure with composition and temperature have been derived from our EMF measurements. Thermodynamic assessments of the partial molar quantities ? overlineH(O 2) and ? overlineS(O 2) for lead-doped Bi-2212 and lead-free Bi-2212 indicate that the solid-state decomposition of these bismuth cuprates at low oxygen partial pressure can be represented by the diphasic CuO?Cu 2O system.

Tetenbaum, M.; Hash, M.; Tani, B. S.; Maroni, V. A.

1996-02-01

315

Bending Behavior of Monolithic Ba(Ti,Sn)O3-Ceramics with a Functionally Gradient of the Piezoelectric Properties.  

National Technical Information Service (NTIS)

Functionally Gradient Materials are suitable for bending devices due to reduced internal mechanical stresses and lower production costs. Monolithic BaTi(sub l-x)Sn(sub x)O(sub 3) (BTS) ceramics with a gradient of the Sn-content (0.075 less than or equal x...

R. Steinhausen A. Kouvatov C. Pientsclilce W. Seifert H. Beige

2003-01-01

316

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

317

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

NASA Astrophysics Data System (ADS)

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

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

2014-01-01

318

Advanced piezoelectric materials for medical ultrasound transducers  

Microsoft Academic Search

A number of materials have recently been developed specifically for advanced ultrasound applications. These are high-density ceramics, fine grain ceramics, high dielectric constant ceramics, and single crystal piezoelectrics. Improvements in properties resulting from these materials range from greater strength and improved machinability to increased transducer element capacitance and coupling. The resulting transducer advances include high frequency arrays (?20MHz), high sensitivity

Wesley Hackenberger; Paul W. Rehrig; Timothy Ritter; Thomas Shrout

2001-01-01

319

Thermal cycling reliability of lead free solders for automotive applications  

Microsoft Academic Search

The solder joint reliability of ceramic chip resistors assembled to laminate substrates has been a long time concern for systems exposed to harsh environments such as those found in automotive and aerospace applications. This is due to a combination of the extreme temperature excursions experienced by the assemblies along with the large coefficient of thermal expansion mismatches between the alumina

J. C. Suhling; H. S. Gale; R. Wayne Johnson; M. N. Islam; T. Shete; P. Lall; M. J. Bozack; J. L. Evans; Ping Seto; T. Gupta; J. R. Thompson

2004-01-01

320

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

321

Comparison of the frequency and physical nature of the lowest order parasitic mode in single crystal and ceramic 2-2 and 1-3 piezoelectric composite transducers.  

PubMed

This work describes an investigation into the first order parasitic mode (i.e., that closest to the fundamental thickness mode) that can occur in 2-2 and 1-3 thickness drive piezoelectric composite transducers. Specifically, the authors compare the performance of piezoceramic and piezocrystal composites with a common passive phase. A local Lamb wave approach is used to describe the generation of such modes, and the validity of this theory is investigated over the entire volume fraction range. It is shown that, when the parasitic mode is primarily generated by Lamb wave activity in the passive phase, both active materials demonstrate similar behavior. However, at higher volume fractions, the first order mode is related to the lateral resonance of the active material, and quite different behavior may be observed between the two sets of devices. The phase velocity of the parasitic modes in each device configuration was investigated by a combination of experimental measurement on a number of transducers along with simulations using the finite-element code PZFlex. Both 2-2 and 1-3 composites made from the single crystal materials pzn-4.5%pt, pzn-8%pt, and pmn-30%pt were investigated along with composites made from pzt5h ceramic. The PZFlex results are compared with experimental impedance analysis and laser scanning of surface displacement, with good agreement demonstrated. By comparing two very different active materials, additional insight into parasitic resonant activity within composite devices is demonstrated. PMID:16921903

Robertson, David; Hayward, Gordon; Gachagan, Anthony; Murray, Victor

2006-08-01

322

Phase transition and piezoelectric properties of (Pb, La) (Zr, Ti)O3 ceramics prepared from spray-dried powders  

Microsoft Academic Search

PLZT ceramic with compositions having molecular formulas (Pb,1-3x\\/2)La?x\\/2)(ZryTi1-3)O3 with O ltm I ltm 0.1 and 0.5 ltm y ltm 0.6 were prepared by cold compaction and sintering of chemically prepared powders. These powders were obtained by spray dried nitrates. Ferroelectric tetragonal, ferroelectric rhombohedral and paraelectric cubic phases of the compositions were identified and morphotropic phase boundary having <1 at.% transition

Ramji Lal; S. C. Sharma; Rajiv Dayal

1993-01-01

323

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

NASA Astrophysics Data System (ADS)

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

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

2014-02-01

324

Modeling Material Properties of Lead-Free Solder Alloys  

NASA Astrophysics Data System (ADS)

A full set of physical and thermophysical properties for lead-free solder (LFS) alloys have been calculated, including liquidus/solidus temperatures, fraction solid, density, coefficient of thermal expansion, thermal conductivity, Youngs modulus, viscosity, and liquid surface tension, all as a function of composition and temperature (extending into the liquid state). The results have been extensively validated against data available in the literature. A detailed comparison of the properties of two LFS alloys Sn-20In-2.8Ag and Sn-5.5Zn-4.5In-3.5Bi with Sn-37Pb has been made to show the utility and need for calculations that cover a wide range of properties, including the need to consider the effect of nonequilibrium cooling. The modeling of many of these properties follows well-established procedures previously used in JMatPro software for a range of structural alloys. This paper describes an additional procedure for the calculation of the liquid surface tension for multicomponent systems, based on the Butler equation. Future software developments are reviewed, including the addition of mechanical properties, but the present calculations can already make a useful contribution to the selection of appropriate new LFS alloys.

Guo, Zhanli; Saunders, Nigel; Miodownik, Peter; Schill, Jean-Philippe

2008-01-01

325

Development of piezoelectric composites for transducers  

NASA Astrophysics Data System (ADS)

For the past decade and a half, many different types of piezoelectric ceramic-polymer composites have been developed intended for transducer applications. These diphasic composites are prepared from non-active polymer, such as epoxy, and piezoelectric ceramic, such as PZT, in the form of filler powders, elongated fibers, multilayer and more complex three-dimensional structures. For the last four years, most of the efforts have been given to producing large area and fine scale PZT fiber composites. In this paper, processing of piezoelectric ceramic-polymer composites with various connectivity patterns are reviewed. Development of fine scale piezoelectric composites by lost mold, injection molding and the relic method are described. Research activities of different groups for preparing large area piezocomposites for hydrophone and actuator applications are briefly reviewed. Initial development of electrostrictive ceramics and composites are also

Safari, A.

1994-07-01

326

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

327

Feature of morphotropic phase boundary of yBiGaO{sub 3}-(1-x-y)BiScO{sub 3}-xPbTiO{sub 3} high-temperature piezoelectric ceramics  

SciTech Connect

yBiGaO{sub 3}-(1-x-y)BiScO{sub 3}-xPbTiO{sub 3} (BGSPT) ternary piezoelectric ceramics were fabricated by using conventional mixed oxide ceramic processing. It was found that the introduction of BiGaO{sub 3} into BiScO{sub 3}-PbTiO{sub 3} system would cause a shift of morphotropic phase boundaries (MPBs), from x=0.64, y=0 to x=0.56, y=0.155; and an increase of Curie temperature (T{sub C}) near MPB, from 450 up to 494 deg. C, respectively. BGSPT ceramics possessed higher T{sub C} ({approx}494 deg. C) and high piezoelectric coefficient (d{sub 33}{approx}180 pC/N), and showed the different rule of the Curie temperature near MPB versus the end member tolerance factor (t). The mechanism of higher T{sub C} in BGSPT system was also proposed.

Jiang Yihang; Qin Baoquan; Yue Xi; Zhao Yi; Jiang Yuzhi; Xiao Dingquan; Zhu Jianguo [College of Materials Science and Engineering, Sichuan University, Chengdu 610064 (China)

2008-04-01

328

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

329

Structural refinement and optical band gap studies of manganese-doped modified sodium potassium lithium niobate lead piezoelectric ceramics  

NASA Astrophysics Data System (ADS)

Li-doped NKLN ceramic (Na0.5 K0.5)0.935Li0.065NbO3 (NKLN935) in pure and MnO2 doped compositions have been revisited to carry out a detailed analysis of the structural and optical properties. Rietveld analysis of the X-ray diffraction (XRD) pattern reveals the system to be tetragonal (space group P4mm). UV-Visible (UV-Vis) spectroscopy and an equivalent Kubelka-Munk function is used to obtain the optical band gap values. It is reported that with increasing Mn doping, the band gap values decreases, which has been analyzed and understood in terms of the tetragonal structure and is found to be consistent with dielectric properties.

Mishra, S. K.; Mishra, R. K.; Brajesh, Kumar; Ray, Rajyavardhan; Himanshu, A. K.; Pandey, H. K.; Singh, N. K.

2014-05-01

330

Doping effects of CuO additives on the properties of low-temperature-sintered PMnN-PZT-based piezoelectric ceramics and their applications on surface acoustic wave devices.  

PubMed

To develop the anisotropic ceramic substrate with low sintering temperature for surface acoustic wave (SAW) applications, the low cost and feasible material with moderate piezoelectric properties, good dielectric properties, and higher Curie temperature were explored. The piezoelectric ceramics with compositions of Pb[(Mn(1/3)Nb(2/3))(0.06-) (Zr(0.52)Ti(0.48))0.94] O(3) (PMnN-PZT) + 0.5 wt.% PbO + x wt.% CuO (0.05 = x = 0.3) had been prepared by the conventional mixed-oxides method. CuO dopants were used as the sintering aid to improve the bulk density under low sintering temperature (i.e., 980-1040 degrees C). The phase structures, microstructures, frequency behavior of dielectric properties (up to 50 MHz), piezoelectric properties, ferroelectric properties, and temperature stability with the amount of CuO additive were systematically investigated. Experimental results showed that the sintering temperature could be lowered down to 1020 degrees C and still keep reasonably good piezoelectric activity (i.e., high electromechanical coupling factor (k(p)), (k(t)) and dielectric and ferroelectric properties. The preferable composition, obtained at x = 0.1, presented the values of the electromechanical coupling factor (k(p)) (k(t)), mechanical quality factor (Q(m)), piezoelectric charge constant (d(33)), dielectric constant, dielectric loss, temperature coefficient of resonant frequency (TCF(B)), and Curie point (T(c)) of 0.54, 0.48, 850, 238 pc/N, 1450, 0.0023, 1.1 kV/mm, 26 coul/cm(2), -150 ppm/ degrees C, and 348 degrees C. Using this developed low-temperature-sintered material to make the piezoelectric substrate, the SAW filter was fabricated and its properties were measured. Results showed that this device possessed very high value of k(2)(7.13%) with a good TCF (-40.15 ppm/ degrees C), and a surface wave velocity (V(P)) of 2196 m/s. PMID:19411224

Tsai, Cheng-Che; Chu, Sheng-Yuan; Lu, Chun-Hsien

2009-03-01

331

Electron microscopy study of ferroelectric domains and microstructural defects in Bi and Zn-modified Pb(Ni1\\/3Nb2\\/3)O3-PbZrO3-PbTiO3 piezoelectric ceramics  

Microsoft Academic Search

Ferroelectric domain configurations and microstructural defects in the Bi- and Zn-modified Pb(Ni1\\/3Nb2\\/3)O3-PbZrO3-PbTiO3 piezoelectric ceramics were investigated by transmission electron microscopy (TEM) and selected area electron diffraction. In the samples with tetragonal symmetry, labyrinthic domain configurations with 90deg a-c domains were observed besides the herringbone-like configuration, parallel band-shaped and\\/or wedge-shaped domains. Polar nanodomains with local random contrast were observed in the

X. H. Zhu; Y. Song; J. M. Zhu; S. H. Zhou; Z. G. Liu

2009-01-01

332

Piezoelectric properties of (1 ? x)Pb(Zr 1\\/2Ti 1\\/2)O 3 xPb(Zn 1\\/3Nb 2\\/3)O 3 ceramics prepared by the columbite(wolframite) precursor method  

Microsoft Academic Search

Solid solutions of the perovskite structure, (1?x)Pb(Zr1\\/2Ti1\\/2)O3xPb(Zn1\\/3Nb2\\/3)O3 with x=0.10.5, were synthesized via the columbite(wolframite) precursor method. The phase development of calcined powder precursors was analyzed by X-ray diffraction. Phase-pure perovskite of PZNPZT ceramics was obtained over a wide compositional range. The microstructure and piezoelectric properties were characterrized by means of scanning electron microscopy (SEM), d33 measurements and impedance analysis. It

N. Vittayakorn; C. Puchmark; G. Rujijanagul; X. Tan; D. P. Cann

2006-01-01

333

Structure, microstructure and dielectric properties of 100- x(Bi0.5Na0.5)TiO3- x[SrTiO3] composites ceramics  

NASA Astrophysics Data System (ADS)

In this paper, lead-free 100- x(Bi0.5Na0.5)TiO3- x[SrTiO3] composites ceramics with (0? x?9) were synthesized by the solid-state reaction method. Their structure, dielectric, ferroelectric and piezoelectric properties were investigated. X-ray diffraction patterns, Rietveld refinement data and Raman spectra revealed that the SrTiO3 cubic structure was completely diffused into the (Bi0.5Na0.5)TiO3 lattice with rhombohedral structure. The scanning electron microscopy images showed change in grain morphology from rectangular-like to quasi-spherical grain with increase in SrTiO3 content. The dielectric permittivity increases, the Curie temperature decreases and the peaks become broaden with raise of SrTiO3 content. Ferroelectric and piezoelectric properties of these composites ceramics showed degenerated behavior with increase of SrTiO3.

Parija, B.; Rout, S. K.; Cavalcante, L. S.; Simes, A. Z.; Panigrahi, S.; Longo, E.; Batista, N. C.

2012-11-01

334

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

335

Investigation of Structural and Electrical Properties of B-Site Complex Ion (Mg1/3Nb2/3)4+-Modified High-Curie-Temperature BiFeO3-BaTiO3 Ceramics  

NASA Astrophysics Data System (ADS)

B-site complex ion (Mg1/3Nb2/3)-modified high-temperature ceramics 0.71BiFeO3-0.29BaTi1-x (Mg1/3Nb2/3) x O3 (BF-BTMNx) have been fabricated by the conventional solid-state reaction method. The compositional dependence of the phase structure, electrical properties, and depolarization temperature of the ceramics was studied. The main phase structure of BF-BTMNx ceramics is perovskite phase with pseudocubic symmetry. The experimental results show that the dielectric and piezoelectric properties, and temperature stability strongly depend on the (Mg1/3Nb2/3)4+ content. The optimum (Mg1/3Nb2/3) content enhances the piezoelectric properties, Curie temperature, and depolarization temperature. The ceramic with x = 1% exhibited enhanced electrical properties of d 33 = 158 pC/N and k p = 0.322, combined with high-temperature stability with Curie temperature of T c = 453C and depolarization temperature of T d = 400C. These results show that the ceramic with x = 1% is a promising lead-free high-temperature piezoelectric material.

Zhou, Xiujuan; Zhou, Changrong; Zhou, Qin; Yang, Huabin; Cen, Zhenyong; Cheng, Jun; Cao, Lei; Fan, Qiaolan

2014-01-01

336

WEEE, RoHS, and what you must do to get ready for lead-free electronics  

Microsoft Academic Search

The transition to lead-free electronics requires surmounting a host of technical, socio-political and economical issues. This paper discusses key concerns in lead-free product development, and provides guidelines to help equipment manufacturers efficiently implement a transition to lead-free electronics. The guidelines address key questions confronting the industry, including those related to lead-free compliance, lead-free part and supplier selection, lead-free manufacturing, and

Valrie Eveloy; Sanka Ganesan; Yuki Fukuda; Ji Wu; Michael G. Pecht

2005-01-01

337

Mediating the contradiction of d33 and TC in potassium-sodium niobate lead-free piezoceramics.  

PubMed

For potassium-sodium niobate, the piezoelectric constant (d33) was usually improved by sacrificing the Curie temperature (TC). In this work, a material system of 0.992(K0.46Na0.54)0.965Li0.035Nb(1-x)Sb(x)O3-0.008BiScO3 has been designed and prepared with the aim of achieving both a large d33 and a high TC at the same time. The chemical compositions are found to be homogeneously distributed in the ceramics. The introduction of Sc is found to be responsible for different grain sizes. The rhombohedral-tetragonal phase coexistence zone lies in the composition range of 0.02ceramic is thermally stable in terms of ferroelectric properties. The change in the domain-wall activities induced by the configuration variation of defect dipoles upon annealing is believed to be responsible for the variation in the d33 at different temperatures. The ceramic with x = 0.025 shows a good comprehensive performance of d33 ? 325 pC/N and k(p) ? 48%, together with a high T(C) of ~358 C, demonstrating that this material system is a promising candidate for high-temperature piezoelectric applications. PMID:24219128

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

2013-11-13

338

Thermal Cycling Ramifications of Lead-Free Solder on the Electronic Assembly Repair Process  

Microsoft Academic Search

The conversion from tin-lead to lead-free electron- ics has created concern amongst engineers about the reliability of electronic assemblies and the ramifications that reliability changes may have on the life cycle cost and availability of critical systems that use lead-free electronics. In order to analyze the impact of the tin-lead to lead-free electronics conversion in terms of life cycle cost

Andrew C. Chaloupka; Peter A. Sandborn; Anthony Konoza

2011-01-01

339

Piezoelectric scanners  

NASA Astrophysics Data System (ADS)

Bimorph piezoelectric elements show relative large axial displacements at moderate voltages. Their response to voltage variations is very fast. The reproducibility of the displacement is practically limited only by the mechanical and electrical supplementary equipment. In combination with a deflection mirror linear scans or two-dimensional scan pattern can be generated. Fast scanning with good linearity and repeatability is possible, either in a resonant mode or in a random access mode. However, the hysteresis of the piezoelectric material and the large capacitance of the elements impose some constraints on the applicability of the piezoelectric scanners. In the first part of the paper the properties of piezoelectric elements are discussed in view of scanner application; in the second part an experimental single mirror two-axis piezoelectric scanner is described. Some suggestions for future applications of piezoelectric scanners are made.

Hohner, M.; Manhart, S.

1987-03-01

340

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

NASA Astrophysics Data System (ADS)

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

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

2012-10-01

341

Manufacturing feasibility of several lead-free solders for electronic assembly.  

National Technical Information Service (NTIS)

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 s...

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

1994-01-01

342

High precise control method for a new type of piezoelectric electro-hydraulic servo valve  

Microsoft Academic Search

A new type of piezoelectric electro-hydraulic servo valve system was proposed. And then multilayer piezoelectric actuator\\u000a based on new piezoelectric ceramic material was used as the electricity-machine converter of the proposed piezoelectric electro-hydraulic\\u000a servo valve. The proposed piezoelectric electro-hydraulic servo valve has ascendant performance compared with conventional\\u000a ones. But the system is of high nonlinearity and uncertainty, it cannot achieve

Miao-Lei Zhou; Yan-tao Tian; Wei Gao; Zhi-gang Yang

2007-01-01

343

Synthesis And Characterization Of Lead Free K0.33Na0.67(NbO3) MPB System  

NASA Astrophysics Data System (ADS)

Lead-free K0.33Na0.67(NbO3), a morphotropic phase boundary (MPB) composition of Potasium Sodium Niobate (KNN) system has been synthesized in single perovskite phase by partial co-precipitation method. X-ray studies revealed monoclinic structure at room temperature. SEM characterization of the sintered ceramics revealed dense and homogeneous packing of grains. Room temperature (RT) dielectric constant (?r) and dielectric loss (tan?) at 1 KHz were found to be ~388 and 0.03 respectively , whereas a relatively high density ?~4.45 g/cm3, remnant polarization (Pr)~4.95 ?c/cm2, coercive field (Ec)~5.60 kV/cm, Curie temperature (Tc)~370 C have been observed.

Pattanaik, M.; Kumar, P.

2010-12-01

344

Piezoelectricity and local structural distortions in (Na0.5Bi0.5)1-xSrxTiO3-Bi12TiO20 flexoelectric-type polar ceramics  

NASA Astrophysics Data System (ADS)

We have previously described sintered Na0.5Bi0.5TiO3-Bi12TiO20 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 (Na0.5Bi0.5)1-xSrxTiO3-Bi12TiO20 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 BiO5 polyhedra and TiO6 octahedra in the SrTiO3-Bi12TiO20 ceramic. The macroscopic polarization may be due to the partial alignment of these distorted units located within the grain boundary amorphous phases. Bi12TiO20 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.

2012-08-01

345

Piezoelectric slotted ring transducer.  

PubMed

Analytical treatment of a slotted piezoelectric ceramic ring transducer vibrating in flexure is presented. The mode shape of the slotted ring vibration is determined, and parameters of the equivalent electromechanical circuit of the transducer are calculated. Possibilities to optimize the effective electromechanical coupling coefficient of the transducer by combining active and passive materials are considered. Acoustic loading for typical projectors made from slotted rings is estimated. Challenges in implementing the slotted ring transducers in terms of depth limitation and radiated power are discussed. PMID:23742342

Aronov, Boris S

2013-06-01

346

Manufacturing feasibility of several lead-free solders for electronic assembly  

SciTech Connect

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 study demonstrated the feasibility of using several of the lead-free solders tested in a surface mount application and identified specific areas (e.g., paste formulation, board finishes, reflow parameters) for improving the manufacturing performance.

Jackson, A.M.; Artakl, I. [AT and T Bell Labs., Princeton, NJ (United States); Vianco, P.T. [Sandia National Labs., Albuquerque, NM (United States)

1994-03-01

347

Manufacturing feasibility of several lead-free solders for electronic assembly  

NASA Astrophysics Data System (ADS)

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 study demonstrated the feasibility of using several of the lead-free solders tested in a surface mount application and identified specific areas (e.g., paste formulation, board finishes, reflow parameters) for improving the manufacturing performance.

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

348

Piezoelectric Film.  

ERIC Educational Resources Information Center

Presents activities that utilize piezoelectric film to familiarize students with fundamental principles of electricity. Describes classroom projects involving chemical sensors, microbalances, microphones, switches, infrared sensors, and power generation. (MDH)

Garrison, Steve

1992-01-01

349

Production of fine spherical lead-free solder powders by hybrid atomization  

Microsoft Academic Search

Considerable R&D efforts in last decade have identified several promising lead-free tin alloys for the replacement of lead-containing solders in microelectronic applications. However, it is difficult or uneconomical to produce high-quality solder balls industrially by means of conventional atomization methods. To produce acceptable lead-free solder balls efficiently and industrially, a novel powder-making process change to active voice. Hybrid Atomization that

Kazumi Minagawa; Hideki Kakisawa; Yoshiaki Osawa; Susumu Takamori; Kohmei Halada

2005-01-01

350

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

Microsoft Academic Search

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

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

2006-01-01

351

Sn2.5Ag0.5Cu lead free solder balls with \\  

Microsoft Academic Search

Recently, environmental-friendly products have significantly increased the development of lead free solder material. Some products are already in production and most of semiconductors will be released lead-freely. Among the various lead-free solders, the SnAgCu family of solders has been known as one of the leading candidates for high volume mass-production. However, SnAgCu still has a discoloration issue during ir-reflow and

R. Lee; Wha Soo Sin; Jong Keun Jeon; Heui Seog Kim

2005-01-01

352

The influence of multiple reflow cycles on solder joint voids for lead-free PBGAs  

Microsoft Academic Search

Lead-free soldering is becoming a common practice in the electronics industry because of the growing general opposition to lead-containing solders. The reliability of lead-free solders has been studied a lot recently, but knowledge of it is still incomplete and many issues related to them are under heavy debate. This paper presents results from a study of the formation of voids

S. T. Nurmi; J. J. Sundelin; E. O. Ristolainen; T. Lepist

2003-01-01

353

Structure, electrical, mechanical and wettability of quenched lead-free solder alloys  

Microsoft Academic Search

The experimental results obtained from the double bridge method, Vickers microhardness tester and dynamic resonance technique are used to evaluate the electrical resistivity, hardness, internal friction and elastic properties of binary, ternary and quaternary tin based lead-free solder alloys. In addition, structure and wettability of these solder alloys have been studied and analyzed. The quenched Sn91Zn9 Bi1Cu2 lead-free solder alloy

Mustafa Kamal; M. S. Meikhail; Abu Bakr El-bediwi; El-said Gouda

2005-01-01

354

Piezoelectric properties of new ternary Bi1/2(Na, Li)1/2TiO3-(Bi1/2K1/2)TiO3-Ba0.85Ca0.15Ti0.90Zr0.10O3 ceramics  

NASA Astrophysics Data System (ADS)

0.852[Bi1/2(Na1- x Li x )1/2]TiO3-0.110(Bi1/2K1/2)TiO3-0.038Ba0.85Ca0.15Ti0.90Zr0.10O3 (BNLT-BKT-BCTZ- x) new ternary piezoelectric ceramics were fabricated by the conventional solid-state method, and their piezoelectric properties as a function of the Li content were mainly investigated. A stable solid solution with a single perovskite structure has been formed, and the depolarization temperature ( T d) of these ceramics was identified by using the temperature dependence of the dielectric loss. The T d value of these ceramics gradually decreases, while the T m value increases with increasing the Li content. The dielectric constant increases and the dielectric loss decreases with increasing the Li content, and an enhanced piezoelectric behavior of d 33223 pC/N and k p35.2 % has been demonstrated in these ceramics with x=0.06.

Wu, Jiagang; Qiao, Sha; Zhu, Jianguo; Xiao, Dingquan

2012-11-01

355

Piezoelectric Energy Harvester for Batteryless Switch Devices  

NASA Astrophysics Data System (ADS)

This study investigated a piezoelectric energy-harvesting system for a mechanical switch device. Piezoelectric ceramics of 0.4Pb(Mg1/3Nb2/3)O3--0.25PbZrO3--0.35PbTiO3 were prepared by using a conventional solid-state reaction method. Li2O, Bi2O3, and CuO additions were used as sintering aids to develop piezoelectric ceramics for low-temperature sintering. Multilayer piezoelectric ceramics with 10 10 3 mm3 sizes and with Ag--Pd inner electrodes were manufactured by using the conventional tape-casting method with the prepared powder. A prototype of a piezoelectric batteryless switch device using the multilayer ceramics was produced. It showed an output peak-to-peak voltage of 3.8 V and an output power per strike of 18 ?W. The performance of the device was good enough for practical use.

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

2013-10-01

356

3K-1 Integrated and Flexible Piezoelectric Ultrasonic Transducers  

Microsoft Academic Search

Thick (>40 mum) ceramic films as piezoelectric and ultrasonic transducers (UTs) have been successfully deposited on metallic and non-metallic substrates by a spray technique. In the film fabrication a composite consisting of piezoelectric powders well mixed with solution of high dielectric constant is directly sprayed onto the substrate. It is then dried, fired or annealed by heat. Multiple coating is

M. Kobayashi; C.-K. Jen

2006-01-01

357

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

358

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

Microsoft Academic Search

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

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

2007-01-01

359

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

NASA Astrophysics Data System (ADS)

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

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

2009-10-01

360

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

361

Ferroelectric, piezoelectric, pyroelectric studies on BaTi0.95(Ni1/3Nb2/3)0.05O3 ceramic  

NASA Astrophysics Data System (ADS)

The main objective of this paper is to study dielectric, ferroelectric, pyroelectric and piezoelectric proprieties of BaTi0.95(Ni1/3Nb2/3)0.05O3. From dielectric experiments, a single ferroelectric transition temperature of about 300K was found. The ferroelectric hysteresis loops were recorded versus temperature evidencing a saturation polarisation of about 4?C/cm2 and a coercive field of 0.97kV/cm at the lowest temperature. The most promising result for BaTi0.95(Ni1/3Nb2/3)0.05O3 is its effective piezoelectric coefficient d31which reaches 55pCN-1 at room temperature.

Boujelben, F.; Bouzid, H.; Bahri, F.; Maalej, A.; Khemakhem, H.; Simon, A.; Maglione, M.

2010-11-01

362

Piezoelectric and ferroelectric properties of K 0.5Na 0.5NbO 3 ceramics synthesized by spray drying method  

Microsoft Academic Search

Potassiumsodium niobate was synthesized at 800C for 1h using dried precursors in a powder form obtained by the spray drying method. Different samples were sintered from 1060 to 1120C for 2h reaching a relative density as high as 96% of the theoretical value. Piezoelectric and ferroelectric properties were studied for these samples and some of the most prominent results are:

Rigoberto Lpez; Federico Gonzlez; M. P. Cruz; M. E. Villafuerte-Castrejon

363

Piezoelectric properties of (Pb\\/sub 1-x\\/Ba\\/sub x\\/)NaNbO ceramic under pressure along the polarization direction  

Microsoft Academic Search

The authors use x-ray diffraction to study polarization and depolarization under a pressure of 380 MPa in the title ceramic where the value of x falls between 0.1 and 0.6. They establish that the irreversible and reversible changes in the piezomodulus, due to pressure along the direction of polarization, are determined by the phase composition of the ceramic. The greatest

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

1987-01-01

364

Phase formation and characterization of high Curie temperature xBiYbO 3(1 ? x)PbTiO 3 piezoelectric ceramics  

Microsoft Academic Search

Novel perovskite xBiYbO3(1?x)PbTiO3 (BYPT) crystalline solutions were prepared by conventional ceramic processing. The effect of BiYbO3 on the microstructure and electrical properties was investigated, and the reaction mechanism of phase formation was discussed. The results show that the proper calcining temperature is 860C and the optimum sintering temperature is 1140C. It is difficult for BYPT ceramics to obtain phase-pure perovskite

Gao Feng; Hong Rongzi; Liu Jiaji; Li Zhen; Cheng Lihong; Tian Changsheng

2009-01-01

365

Processing, texture quality, and piezoelectric properties of <001>C textured (1-x)Pb(Mg1/3Nb2/3)TiO3 - xPbTiO3 ceramics  

NASA Astrophysics Data System (ADS)

This paper describes the link between texture quality and electromechanical properties for <001>C textured, 0.03(Na1/2Bi1/2)TiO3 - 0.97[0.715Pb(Mg1/3Nb2/3)TiO3 - 0.285PbTiO3] (0.03NBT-0.97[PMN-28.5PT]) ceramics with and without Mn-doping. Here, the subscript C denotes pseudocubic indices. Textured ceramics were prepared by templated grain growth of PMN-25PT on platelet-shaped 0.4(Na1/2Bi1/2)TiO3-0.6PbTiO3 (NBT-0.6PT) templates. Texture fractions of f = 0.92 (for undoped (1-x)Pb(Mg1/3Nb2/3)TiO3-xPbTiO3 (PMN-PT)) and f = 0.49 (for Mn-doped PMN-PT) were determined by fitting 002C XRD pole figures to the March-Dollase model, which was modified to account for symmetry-related 200C and 020C reflections. Using resonance methods, the elastic constants cij, sij, piezoelectric constants dij, eij, gij, hij, dielectric constants ?ij, and coupling coefficients kij of textured PMN-PT ceramics were characterized. It was found that the properties of textured PMN-PT approach the single crystal values along the texture axis (<001>C, also the poling axis), but not in transverse directions. In particular, the elastic compliance sE11 (perpendicular to <001>C) approaches an average of the single crystal sE11 and sE11(45) coefficients, resulting in anomalous -sE12/sE11 ratios of - 0.01 and 0.04 in pure and Mn-doped textured PMN-PT, respectively. The 33-mode properties as measured by resonance-antiresonance methods were d33 = 852 pC/N, k33 = 0.83, ?33 = 3500, and mechanical quality factor Qm = 94 for undoped textured ceramics and d33 = 515, k33 = 0.76, V33 = 2200, and Qm = 714 for Mn-doped textured ceramics.

Poterala, Stephen F.; Trolier-McKinstry, Susan; Meyer, Richard J.; Messing, Gary L.

2011-07-01

366

Additive Processes for Piezoelectric Materials: Piezoelectric MEMS  

Microsoft Academic Search

\\u000a Piezoelectricity has been underutilized in the MEMS world. Fabrication process compatibility, complexity, and the limited\\u000a availability of repeatable and reliable piezoelectric thin films have limited the incorporation of piezoelectric thin films\\u000a in MEMS. Advances in materials processing and a move toward system-in-package (SIP) concepts have pushed piezoelectric thin\\u000a film devices toward mainstream acceptance. The advances in piezoelectric aluminum (AlN) thin

Ronald G. Polcawich; Jeffrey S. Pulskamp

367

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.

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

2014-01-01

368

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

1998-01-01

369

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

NASA Astrophysics Data System (ADS)

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

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

2014-06-01

370

A shear-bending mode high temperature piezoelectric actuator  

NASA Astrophysics Data System (ADS)

A single ring-shape ceramic plate piezoelectric actuator operated in shear-bending mode was proposed for high-temperature operation. The actuator was formed from BiScO3-PbTiO3 ceramic and polarized in the radial direction. A large bending displacement at the center of the actuator was piezoelectrically generated under an applied voltage in the thickness direction due to axial-symmetric shear strain of the ring-shape configuration. The displacement obtained at 200 C was about 20 ?m, 11-14 times that of a normal piezoelectric plate of identical size.

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

2012-07-01

371

Microstructure of BaTiO3--Bi(Mg1/2Ti1/2)O3--BiFeO3 Piezoelectric Ceramics  

NASA Astrophysics Data System (ADS)

The dependence of the ferroelectric and piezoelectric properties of (1-x)(0.33BaTiO3--0.67BiFeO3)--xBi(Mg1/2Ti1/2)O3 (x = 0, 0.05, 0.10, and 0.15) on Bi(Mg1/2Ti1/2)O3 content x associated with microstructural changes is studied. From the behaviour of electric field-induced polarization and strain, polarization switching and depolarizing become easier as Bi(Mg1/2Ti1/2)O3 content x increases. Remanent polarization and dielectric constant decrease, while polarization saturation field increases with increasing x. Microstructural observation reveals that Bi(Mg1/2Ti1/2)O3 addition enhances the compositional fluctuation of BaTiO3/BiFeO3 ratio, which probably creates a nanometre-sized domain region with slightly BaTiO3-rich composition. Since this nanometre-sized domain may cause relatively large responses of polarization and strain to the applied electric field, an appropriate amount of Bi(Mg1/2Ti1/2)O3 enhances the electric field-induced strain, resulting in the largest piezoelectric response at x = 0.05. However, excessive Bi(Mg1/2Ti1/2)O3 degrades polarization and strain characteristics, because a number of Ba(Fe1-xMgx/2Tix/2)12O19 grains are created as a secondary phase and cause the segregation of excess bismuth oxide phases with low dielectric constant into the boundaries of the ferroelectric/piezoelectric grains.

Yabuta, Hisato; Shimada, Mikio; Watanabe, Takayuki; Hayashi, Jumpei; Kubota, Makoto; Miura, Kaoru; Fukui, Tetsuro; Fujii, Ichiro; Wada, Satoshi

2012-09-01

372

Piezoelectric Properties of Spark-Plasma-Sintered (Na0.5K0.5)NbO3-PbTiO3 Ceramics  

Microsoft Academic Search

In the search for high-performance piezoelectrics, (1-y)(Na0.5K0.5)NbO3-yPbTiO3 (y<= 0.50) solid solution has been prepared using the spark-plasma-sintering method. Dielectric investigation reveals that both the ferroelectric phase transition temperatures and the peak value of the dielectric constant are strongly suppressed in the low y range. However, improved electromechanical coupling constants are observed at the same y range. These properties are explained

Ruiping Wang; Rongjun Xie; Tadashi Sekiya; Yoshiro Shimojo; Yoshio Akimune; Naoto Hirosaki; Mitsuru Itoh

2002-01-01

373

Lead-free solders: issues of toxicity, availability and impacts of extraction  

NASA Technical Reports Server (NTRS)

This project set out to evaluate the critical issues of toxicity and public health effects, material availability, and the environmental impacts of raw material extraction and metal finishing, with the goal of using environmental impact as a factor in selecting feasible lead-free alloys.

Ku, A.; Shapiro, A. A.; Kua, A.; Ogunseitan, O.; Saphores, J. D.; Schoenung, J. M.

2003-01-01

374

Electrical modeling and characterization of packaging solutions utilizing lead-free second level interconnects  

Microsoft Academic Search

This paper presents measured and modeled results of two novel lead-free interconnect solutions. A surface mounted Copper Column Grid Array (CuCGA) and a demountable Spring Land Grid Array (SLGA) will be characterized and compared to the standard Column Grid Array (CGA). The geometries and materials required for reliable connections often compete with the ones required for adequate electrical performance. To

Daniel P. O'Connor; Harvey Hamel; Christopher Spring; Jean Audet

2003-01-01

375

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...

376

Electrically Conductive Carbon Nanotube Adhesives on Lead Free Printed Circuit Board Surface Finishes  

Microsoft Academic Search

Electrically conductive adhesives are attractive alternatives to solder and die attach materials in electronic assemblies particularly in the lead free era. Compared to metal filled conductive adhesives, multiwall carbon nanotube (MWCNT) filled adhesives are lightweight, corrosion resistant, high strength and resistant to metal migration. Previous studies of MWCNT filled epoxies on bare copper printed circuit boards identified contact resistance as

Keerthivarma Mantena; Jing Li; J. K. Lumpp

2008-01-01

377

DOES PCB PAD FINISH AFFECT VOIDING LEVELS IN LEAD-FREE ASSEMBLIES?  

Microsoft Academic Search

With European environmental legislation and market forces driving the change to lead-free solders for printed circuit board assembly, there will be significant changes in the soldering process. Voiding is one of the known major consequences of these process changes exaggerated by the use of new soldering materials. Excessive voiding can lead to poor quality joints, BGA \\

David Bernard; Keith Bryant

378

Failure mode and effects analysis of a process of reflow lead-free soldering  

Microsoft Academic Search

There are many methods usable for production process optimization. The paper describes the use of failure mode and effects analysis (FMEA of a process type) for the process of lead-free soldering improvement. The schedule of FMEA has been set. Then a flow chart of a process has been drawn and critical failures including their consequences for the final product have

P. Mach; A. Duraj

2008-01-01

379

A Model Study of Profiling for Voiding Control at Lead-free Reflow Soldering  

Microsoft Academic Search

Voiding is attributed to the flux outgassing within the solder joints when the solder is at molten state. The effect of reflow profile on voiding at microvia for lead-free soldering is strongly dependent on the flux chemistry. In general, wetting is more important than melting outgasing behavior, and can be enhanced by employing a higher melting energy, including both higher

Yan Liu; William Manning; Benlih Huang; Ning-Cheng Lee

380

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...

381

Effects of Physical Aging on the Stress-Strain and Creep Behaviors of Lead Free Solders  

Microsoft Academic Search

Solder materials demonstrate evolving properties that change significantly with environmental exposures such as isothermal aging and thermal cycling. Such physical aging effects are exacerbated at higher temperatures typical of thermal cycling qualification tests for harsh environment electronic packaging. In this work, measurements of thermal aging induced material behavior evolution have been performed for tin-lead and lead free solders. Extreme care

Hongtao Ma; J. C. Suhling; P. Lall; M. J. Bozack

2006-01-01

382

Effects of aging on the stress-strain and creep behaviors of lead free solders  

Microsoft Academic Search

Solder materials demonstrate evolving micro structure and mechanical behavior that changes significantly with environmental exposures such as isothermal aging and thermal cycling. These aging effects are greatly exacerbated at higher temperatures typical of thermal cycling qualification tests for harsh environment electronic packaging. In the current study, mechanical measurements of thermal aging effects and material behavior evolution of lead free solders

Hongtao Ma; Jeffrey C. Suhling; Pradeep Lall; Michael J. Bozack

2006-01-01

383

Influence of moisture contamination of lead-free transparent dielectric slurry for tape casting  

Microsoft Academic Search

During the process of milling glass powders of lead-free transparent dielectric materials, moisture contamination from the air affects the properties of the slurry of the green sheet and of the fired films. Several solvents used to gain suitable dispersion stability of the slurry and dispersants, such as ionic and polymeric agents, are studied for optimization of the slurry composition of

Young-Jei Oh; Byung-Koog Jang; Hyun-Oh Kim

2011-01-01

384

Effect of lead-free frit on conductivity of nanoparticles-aided silver paste.  

PubMed

Silver thick films were prepared from lead-free silver paste adding silver nanoparticles for low sintering temperature, and the effect of glass frit content on conductivity in the films was investigated. Silver pastes with different glass contents were prepared by mixing micron-scale silver powder of 1.6 microm and nanoparticles of 30-50 nm in size. To prepare lead-free silver paste, 5 wt% of the silver nanoparticles as a sintering aid were added to the micron-scale silver powder. Then, 3 wt%, 6 wt%, and 9 wt% of lead-free frits were added to the mixed powders. Using the paste, thick films were prepared by a screen printing on an alumina substrate and then the films were sintered at temperatures from 300 degrees C to 550 degrees C. As increasing the sintering temperature and content of lead-free frit, the thick films showed dense microstructure. The glass frit enhanced to develop denser microstructure by liquid phase sintering. However, excess of glass content increased sheet resistivity due to the formation of glass pool separated from particle network. Furthermore, the nanoparticles can assist to develop a conductive network in the film. The films with 6 wt% of glass frit had the best conductive network and the lowest sheet resistivity of 3.2 microomega cm. PMID:19198449

Park, Sung Hyun; Seo, Dong Seok; Lee, Jong Kook

2008-10-01

385

Effects of microstructure evolution on damage accumulation in lead-free solder joints  

Microsoft Academic Search

The wear out of lead-free solder joints under realistic loading conditions has been shown to deviate strongly from predictions based on current damage accumulation models. We argue that the deviation must be due to the simultaneous evolution of solder properties and damage. In general, solder properties and fatigue behaviors are determined by microstructure and damage accumulation mechanisms. Literature has reported

Linlin Yang; Liang Yin; Brian Roggeman; Peter Borgesen

2010-01-01

386

Structural Health Monitoring Using Smart Piezoelectric Material  

Microsoft Academic Search

The application of the electromechanical impedance method to detect the presence of damage and monitor its progression in concrete structures is investigated using finite element analysis. The piezoelectric ceramic (PZT) patch bonded to concrete structures serves as both an actuator and a sensor in high frequency. The various health states of the structure are assessed using the root mean square

Kevin K Tseng; Liangsheng Wang

387

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

388

Joint Lead-Free Solder Test Program for High Reliability Military and Space Applications  

NASA Technical Reports Server (NTRS)

Current and future space and defense systems face potential risks from the continued use of tin-lead solder, including: compliance with current environmental regulations, concerns about potential environmental legislation banning lead-containing products, reduced mission readiness, and component obsolescence with lead surface finishes. For example, the United States Environmental Protection Agency (USEPA) has lowered the Toxic Chemical Release reporting threshold for lead to 100 pounds. Overseas, the Waste Electrical and Electronic Equipment (WEEE) and the Restriction on Hazardous Substances (RoHS) Dicctives in Europe and similar mandates in Japan have instilled concern that a legislative body will prohibit the use of lead in aerospace/military electronics soldering. Any potential banning of lead compounds could reduce the supplier base and adversely affect the readiness of missions led by the National Aeronautics and Space Administration (NASA) and the U.S. Department of Defense (DoD). Before considering lead-free electronics for system upgrades or future designs, however, it is important for the DoD and NASA to know whether lead-free solders can meet their systems' requirements. No single lead-free solder is likely to qualify for all defense and space applications. Therefore, it is important to validate alternative solders for discrete applications. As a result of the need for comprehensive test data on the reliability of lead-free solders, a partnership was formed between the DoD, NASA, and several original equipment manufactures (OEMs) to conduct solder-joint reliability (laboratory) testing of three lead-free solder alloys on newly manufactured and reworked circuit cards to generate performance data for high-reliability (IPC Class 3) applications.

Brown, Christina

2004-01-01

389

Piezoelectric trace vapor calibrator  

SciTech Connect

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

Verkouteren, R. Michael; Gillen, Greg; Taylor, David W. [Surface and Microanalysis Science Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); MicroFab Technologies, Inc., 1104 Summit Avenue, Suite 110, Plano, Texas 75074 (United States)

2006-08-15

390

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 290 fg/l to 1.05 ?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

391

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

392

Cymbal piezoelectric composite underwater acoustic transducer.  

PubMed

The working principle of Cymbal piezoelectric composite underwater acoustic transducer was studied in this paper. PZT-5A piezoelectric ceramic disk was used as piezoelectric phase and brass foil was used as end cap electrode of the Cymbal transducer. The silicon rubber was used as the insulated proof layer of the underwater acoustic transducer. The properties of this transducer used as hydrophone, such as operation frequency, free-field voltage receiving sensitivity and directivity, were investigated. Several kinds of prototype of this transducer were fabricated and the properties of this transducer used as hydrophone were tested. The results show that the properties of this transducer used as hydrophone depend on the dimensions of Cymbal transducer because the piezoelectric properties of this transducer are dependent on the dimensions of Cymbal transducer's end caps. The appropriate dimensions for getting higher free-field voltage receiving sensitivity with -184.7 dB were obtained. PMID:16793099

Li, Denghua; Wu, Min; Oyang, Peixi; Xu, Xiaofei

2006-12-22

393

Derivation of Piezoelectric Losses from Admittance Spectra  

NASA Astrophysics Data System (ADS)

High power density piezoelectrics are required to miniaturize devices such as ultrasonic motors, transformers, and sound projectors. The power density is limited by the heat generation in piezoelectrics, therefore, clarification of the loss mechanisms is necessary. This paper provides a methodology to determine the electromechanical losses, i.e., dielectric, elastic and piezoelectric loss factors in piezoelectrics by means of a detailed analysis of the admittance/impedance spectra. This method was applied to determine the piezoelectric losses for lead zirconate titanate ceramics and lead magnesium niobate-lead titanate single crystals. The analytical solution provides a new method for obtaining the piezoelectric loss factor, which is usually neglected in practice by transducer designers. Finite element simulation demonstrated the importance of piezoelectric losses to yield a more accurate fitting to the experimental data. A phenomenological model based on two phase-shifts and the Devonshire theory of a polarizable-deformable insulator is developed to interpret the experimentally observed magnitudes of the mechanical quality factor at resonance and anti-resonance.

Zhuang, Yuan; Ural, Seyit O.; Rajapurkar, Aditya; Tuncdemir, Safakcan; Amin, Ahmed; Uchino, Kenji

2009-04-01

394

Corrosion characterization of tinlead and lead free solders in 3.5 wt.% NaCl solution  

Microsoft Academic Search

The corrosion resistance of SnPb and several candidate lead free solders were investigated in 3.5wt.% NaCl solution through potentiodynamic polarisation. Results showed that in NaCl solution lead free solders had better corrosion resistance than SnPb solder and the corrosion resistance of lead free solders was similar, but the corrosion resistance of SnAg solder was better than that of SnAgCu and

Dezhi Li; Paul P. Conway; Changqing Liu

2008-01-01

395

Predicting Component Self-Alignment in Lead-Free Reflow Soldering Technology by Virtue of Force Model  

Microsoft Academic Search

Since lead-free soldering is initiated in the electronic industry in 1st of July 2006, studying the behaviour of lead-free solders in depth is more important than ever. Several studies and articles have claimed that lead-free solders do not promote the self-alignment of components, what is in contradiction with the observation of our previous experiments. Dynamic behaviour of SMT (surface mount

Oliver Krammer; Balint Sinkovics; B. Illes

2006-01-01

396

Investigation of High-Power Properties of (Bi,Na,Ba)TiO3 and (Sr,Ca)2NaNb5O15 Piezoelectric Ceramics  

NASA Astrophysics Data System (ADS)

We investigated why the nonlinear behaviors of (Bi,Na,Ba)(Ti,Mn)O3 (BNBTM) ceramics and (Sr,Ca)2NaNb5O15 (SCNN) ceramics occur in comparison with Pb(Zr,Ti)O3-based (PZT) ceramics by evaluating their high-power properties with the distinction between mechanical nonlinearity and temperature dependence of properties. The equivalent stiffness of PZT decreased with increasing vibration velocity and sample temperature. However, the equivalent stiffnesses of BNBTM and SCNN did not depend on vibration velocity, they decreased and increased linearly with an increase in sample temperature, respectively. The nonlinear behavior of PZT originated from the soft-spring effect through which the mechanical nonlinearity was induced and the temperature dependence of stiffness was enhanced. On the other hand, it appeared that the nonlinear behaviors of BNBTM and SCNN originated from the apparent soft- and hard-spring effects through which the temperature dependence of stiffness was induced. The temperature characteristic of elasticity is important for controlling the high-power properties.

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

2013-07-01

397

Switchable Ferroelectric Diode Effect and Piezoelectric Properties of Bi0.9La0.1FeO3 Ceramics  

NASA Astrophysics Data System (ADS)

Multiferroic ceramics Bi0.9La0.1FeO3 are synthesized by solid-state reactions and sintered at various temperatures. The rhombohedral structure with the space group R3c is confirmed by means of x-ray diffraction, and their multiferroic properties are investigated. Bi0.9La0.1FeO3 ceramics sintered at 880C are found to have the lowest leakage current density and the largest saturated polarization among all the samples. A diode-like current-voltage hysteresis that could be switched by an external voltage is observed in the Bi0.9La0.1FeO3 ceramics. A typical butterfly" shaped strain-versus-voltage curve is shown with a maximum strain of 0.09% at 7kV. Room-temperature magnetization exhibits a hysteresis loop, indicating that the modulation of the spin structure of BiFeO3 has been suppressed.

Gong, Yu-Fei; Wu, Ping; Liu, Wei-Fang; Wang, Shou-Yu; Liu, Guang-Yao; Rao, Guang-Hui

2012-04-01

398

Giant electrocaloric effect in lead-free thin film of strontium bismuth tantalite  

NASA Astrophysics Data System (ADS)

Giant electrocaloric effect was observed in lead-free material for the first time. A demonstration of large electrocaloric effect in 200 nm sol-gel thin film SrBi2Ta2O9 is described here. The ferroelectric hysteresis loops and the film permittivity were measured. The extracted data characterized the electrocaloric temperature change, up to 4.93K in 12V (i.e., 0.41 K V-1) near the Curie point. It is concluded that the giant electrocaloric effect exists in lead-free materials, and a large family of layered perovskite oxides may exhibit analogical property. The absence of lead allows eco-friendly application and enhances compatibility with integrated circuit process in future applications.

Chen, Hao; Ren, Tian-Ling; Wu, Xiao-Ming; Yang, Yi; Liu, Li-Tian

2009-05-01

399

Piezoelectric circular ring flexural transducers.  

PubMed

An analytical treatment of the piezoelectric ceramic complete ring transducer undergoing flexural vibrations is presented. Conditions for the electromechanical excitation of the flexural vibrations are discussed and it is shown that the fundamental mode of the flexural vibration of a complete ring can be considered as sufficiently dominant over a broad frequency range. Hence, the one-dimensional equivalent electromechanical circuit representation of the transducer is applicable and all the parameters of the equivalent circuit are determined. Possibilities to optimize the effective coupling coefficient of the transducer by changing the extent of the electrodes on the piezoelectric body are considered. It is shown that for effective operation of the flexural ring transducer as a low frequency hydroacoustic projector the opposing quadrants (or three quadrants in case of a planar array configuration) have to be covered with baffles. The radiation impedance and directional factors of the transducers with baffles are considered. Limitations of the acoustical power radiated by the transducers are discussed. PMID:23927101

Aronov, Boris S

2013-08-01

400

A review of mechanical properties of lead-free solders for electronic packaging  

Microsoft Academic Search

The characterization of lead-free solders, especially after isothermal aging, is very important in order to accurately predict\\u000a the reliability of solder joints. However, due to lack of experimental testing standards and the high homologous temperature\\u000a of solder alloys (T\\u000a h>0.5T\\u000a m even at room temperature), there are very large discrepancies in both the tensile and creep properties provided in current

Hongtao Ma; Jeffrey C. Suhling

2009-01-01

401

Comparison of Printed Circuit Board Property Variations in Response to Simulated Lead-Free Soldering  

Microsoft Academic Search

Use of lead-free solders such as Sn\\/Ag\\/Cu results in exposure of printed circuit boards to higher temperatures during assembly compared with eutectic tin-lead solder. If the thermo-mechanical and electrical properties of the laminate materials get affected by exposure to this higher temperature, that may impact the performance and reliability of the circuit board. Variations, if any, in laminate material properties

Bhanu Sood; Ravikumar Sanapala; Diganta Das; Michael Pecht; C. Y. Huang; M. Y. Tsai

2010-01-01

402

Printed circuit boards for lead-free soldering: materials and failure mechanisms  

Microsoft Academic Search

Purpose This paper aims to evaluate the influence of previous exposure to moisture on delamination and formation of CAF (conductive anodic filament) in printed circuit boards used for lead-free soldering. Design\\/methodology\\/approach The moisture absorption and desorption characteristics of printed circuit boards were evaluated according to the IPC\\/JEDEC J-STD-020C standard for handling of moisture sensitive components. The CAF test

Per Johander; Per-Erik Tegehall; Abelrahim Ahmed Osman; Gran Wetter; Dag Andersson

2007-01-01

403

Effects of Printed Circuit Board Materials on Lead-free Interconnect Durability  

Microsoft Academic Search

This study investigates the effects of printed circuit board (PCB) material on interconnect durability of lead free assemblies. The assemblies involve soldering various packages (array and peripheral) on to FR4, high glass transition temperature (Tg) FR4 and Polyimide (PI) printed circuit boards using Sn3Ag0.5Cu solder alloy. The glass transition temperature of these materials ranges from 130C to 230C. Thermomechanical properties,

Haiyu Qi; S. Ganesan; Ji Wu; M. Pecht; P. Matkowski; J. Felba

2005-01-01

404

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

Microsoft Academic Search

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

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

2011-01-01

405

Failure mode analysis of lead-free solder joints under high speed impact testing  

Microsoft Academic Search

Using an Instron micro-impact system, this study investigates the failure characteristics of 96.5Sn3Ag0.5Cu lead-free solder joints aged at either room temperature or 125C, respectively, and then impacted at shear rates of up to 1m\\/s. Four types of failure mode are identified, namely M1: interfacial fracture with no residual solder left on the pad; M2: interfacial fracture with residual solder left

De-Shin Liu; Chia-Yuan Kuo; Chang-Lin Hsu; Geng-Shin Shen; Yu-Ren Chen; Kuo-Cheng Lo

2008-01-01

406

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

407

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

408

Effect of in addition on Sn-Ag-Sb lead-free solder system  

Microsoft Academic Search

The present study investigates the effect of 1~5 wt.% Indium additions on microstructure, properties and interfacial IMC's formation of Sn-3Ag-2Sb(SAS) lead-free solder alloys. Experimental results show that addition of indium results in formation of intermetallic compounds of Ag-Sn-In phase and InSb phase. Sn atoms in Ag3Sn compound formed originally in Sn-Ag solder system are replaced by In atoms in SAS-xIn

Hwa-Teng Lee; Fok-Foo Lee; Ting-Fu Hong; Hsiao-Wei Chen

2008-01-01

409

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

SciTech Connect

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

Vianco, P.T. [Sandia National Labs., Albuquerque, NM (United States)] [Sandia National Labs., Albuquerque, NM (United States); Mizik, P.M. [Allied-Signal Aerospace Co., Kansas City, MO (United States). Kansas City Div.] [Allied-Signal Aerospace Co., Kansas City, MO (United States). Kansas City Div.

1993-12-31

410

Room-temperature indentation creep of lead-free Sn5%Sb solder alloy  

Microsoft Academic Search

Creep behavior of the lead-free Sn-5%Sb solder alloy was studied by long-time Vickers indentation testing at room temperature.\\u000a Four different conditions of the material were examined. These were unhomogenized cast (UC), homogenized cast (HC), unhomogenized\\u000a wrought (UW), and homogenized wrought (HW) conditions. Based on the steady-state power-law creep relationship, the stress\\u000a exponents were determined through different methods of analysis, and

A. R. Geranmayeh; R. Mahmudi

2005-01-01

411

Strain rate effect and Johnson-Cook models of lead-free solder alloys  

Microsoft Academic Search

Drop\\/impact causes high strain rate deformation in solder joints of microelectronics package. It is important to understand mechanical behavior of solder joints under high strain rate for reliability design of products. In this paper mechanical behaviors of two lead-free solder alloys, Sn3.5Ag and Sn3.0Ag0.5Cu, were investigated by quasi-static tests and the split Hopkinson tension\\/pressure bar testing technique under high strain

Qin Fei; An Tong; Chen Na

2008-01-01

412

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

Microsoft Academic Search

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

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

2006-01-01

413

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

Microsoft Academic Search

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

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

2005-01-01

414

On the advantages of using a hypoeutectic SnZn as lead-free solder material  

Microsoft Academic Search

Hypoeutectic SnZn may be a better choice than the eutectic Sn9Zn as a lead-free solder. We checked the non-equilibrium melting behaviors of a series of SnZn alloys (2.59wt.% Zn) by differential thermal analysis, and found that at a heating rate of 5C\\/min, Sn6.5Zn behaves the same way as the eutectic Sn9Zn in melting. Dipping and spreading tests were carried out

Xiuqin Wei; Huizhen Huang; Lang Zhou; Meng Zhang; Xiaodong Liu

2007-01-01

415

SEM\\/EDS analysis and characterization of gunshot residues from Brazilian lead-free ammunition  

Microsoft Academic Search

The exposition to heavy metal-rich airborne due to fire practicing has forced to the development of heavy metal-free environmental ammunition primers all over the world. Here we characterize the GSR elements present in the Brazilian lead-free ammunition produced by Companhia Brasileira de Cartuchos (CBC) and commercialized by MagTech in the U.S. and Europe under the name CleanRange centerfire cartridges. Both

Andrea Martiny; Andrea P. C. Campos; Marcia S. Sader; Maj Andr L. Pinto

2008-01-01

416

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

SciTech Connect

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

Vianco, P.T. [Sandia National Labs., Albuquerque, NM (United States); Artaki, I. [AT and T Bell Labs., Princeton, NJ (United States). Engineering Research Center

1993-12-31

417

[Shielding evaluation of lead-free board for diagnostic X-rays].  

PubMed

For physical foundation data used in the shielding calculation of structural facilities such as a radiation room, there are air kerma transmissions concerning the thickness of shielding objects, and half value layers and tenth value layers concerning a greatly attenuated wide X-ray beam. Accordingly, we evaluated the above-mentioned items with a lead-free board, which is mixed sulfuric acid calcium and barium sulfate with equiponderance for the amount of sulfuric acid calcium included in the usual plasterboard. Permeability in NCRP Report 147 is expressed by 3 parameters, ?, ? and ?, and shielding objects x. It showed that it corresponds to the measurement point and permeability curve with parameters, ?, ? and ? obtained by nonlinear regression analysis. Furthermore, we calculated the half value layer and tenth value layer concerning the greatly attenuated wide X-ray beam. The evaluated lead-free board, used in this examination, is useful as the shielding material for the diagnosis X-ray and, moreover, the partition wall materials are hard enough, with a board that is even heavier than the usual plaster board. Besides, the use of lead-free materials is friendly to the general environment. PMID:21282911

Katoh, Yoh; Tsukada, Masaru; Mita, Sogo; Fukushi, Masahiro; Nyui, Yoshiyuki; Abe, Shinji; Kimura, Junichi

2010-12-20

418

Transverse piezoelectric mode composites: a new design approach for smart material applications  

NASA Astrophysics Data System (ADS)

Transverse piezoelectric mode ceramic-polymer composites provide several advantages over conventional longitudinal mode composites. It has been shown, from both analytical and experimental results, the hydrostatic performance of 1 - 3 tubular and 2 - 2 plate piezocomposites can be significantly improved by utilizing the transverse piezoelectric effect. By varying the geometry of the piezoelectric ceramics and the configuration of constituent phases, the undesirable components of piezoelectric response of the composites can be eliminated. Moreover, the effective uniaxial and hydrostatic responses can be greatly enhanced by optimizing the physical properties of the constituent phases and the structures of the composites.

Wang, Hong; Zhang, Qi M.; Cross, Leslie E.; Trottier, C. Michael C.

1995-05-01

419

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

420

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

NASA Astrophysics Data System (ADS)

We report the dielectric properties of ( K 0.5 Na 0.5 ) NbO 3 ceramics doped with x wt% of Dy 2 O 3 (x= 0.0-1.5 wt%) using the broadband dielectric spectroscopy. The X-ray diffraction studies showed the formation of perovskite structure signifying that Dy 2 O 3 diffuse into the KNN lattice. Samples doped with x > 0.5 wt% exhibit smaller grain size and lower relative densities. The dielectric properties of KNN ceramics doped with Dy 2 O 3 are enhanced by increasing the Dy 3+ content; among the compositions studied, x = 0.5 wt% exhibited the highest dielectric constant and lowest loss at 1MHz over the temperature range of 30C to 400C. All the samples exhibit maximum dielectric constant at the Curie temperature ( 326C) and a small peak in the dielectric constant at around 165C is due to a structural phase transition. At the request of all authors, and by agreement with the Proceedings Editors, a corrected version of this article was published on 19 June 2014. The full text of the Corrigendum is attached to the corrected article PDF file.

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

2014-06-01

421

High thermal stability of piezoelectric properties in (Na0.5Bi0.5TiO3)x-(BaTiO3)y-(Na0.5K0.5NbO3)1-x-y ceramics  

NASA Astrophysics Data System (ADS)

We report the piezoelectric and ferroelectric properties of (Na0.5Bi0.5TiO3)x-(BaTiO3)y-(Na0.5K0.5NbO3)1-x-y ceramics for Na0.5K0.5NbO3 rich end of composition (x, y <= 0.04 mol. %). These compositions were found to exhibit significantly improved thermal stability of piezoresponse. Variation of dielectric constant as a function of temperature revealed that orthorhombic-tetragonal (To-t) and tetragonal-cubic (Tc) transition temperatures for these compositions were in the vicinity of 0 C and 330 C, respectively. Dynamic scaling and temperature dependent X-ray diffraction analysis were conducted. Results are discussed in terms of intrinsic and extrinsic contributions to the piezoelectric response explaining the temperature dependent behavior.

Gupta, Shashaank; Priya, Shashank

2013-01-01

422

A review on the development of piezoelectric composites for underwater acoustic transducer applications  

Microsoft Academic Search

For future sonar transducer applications that emphasize the detection of acoustical signals in a hydrostatic mode, new piezoelectric composite materials have been developed. Ceramic-polymer composites having `1-3' and `0-3' connectivity patterns are shown to exhibit much higher sensitivities than conventional PZT ceramics. Glass-ceramic composites are free of aging and have potential applications in standard transducers

Robert Y. Ting

1991-01-01

423

A review on the development of piezoelectric composites for underwater acoustic transducer applications  

Microsoft Academic Search

For future sonar transducer applications that emphasize the detection of acoustical signals in a hydrostatic mode, new piezoelectric composite materials have been developed. Ceramic-polymer composites having `1-3' and `0-3' connectivity patterns are shown to exhibit much higher sensitivities than conventional PZT ceramics. Glass-ceramic composites are free of aging, and have potential applications in standard transducers

Robert Y. Ting

1992-01-01

424

Biomimetic Fabrication of Functional Ceramic Composites.  

National Technical Information Service (NTIS)

Thin films and multilayers of functional ceramics have a number of important applications including dielectrics, magnetic recording media, piezoelectric transducers, and integrated optical devices. Variously functionalized self-assembled monolayers, attac...

C. N. Sukenik A. H. Heuer M. R. DeGuire R. J. Collins H. J. Shin

1996-01-01

425

Direct Piezoelectricity of Soft Composite Electrospun Fibers  

NASA Astrophysics Data System (ADS)

Recently soft fiber mats electrospun from solutions of Barium Titanate (BT) ferroelectric ceramics particles and poly lactic acid (PLA) were found to have large (d33 1nm/V) converse piezoelectric signals offering a myriad of applications ranging from active implants to smart textiles. Here we report direct piezoelectric measurements (electric signals due to mechanical stress) of the BT/PLA composite fiber mats at various BT concentrations. A testing apparatus was designed and constructed solely for these measurements involving AC stresses provided by a speaker in 10Hz-10kHz frequency range. The piezoelectric constant d33 1nC/N was found to be in agreement with the prior converse piezoelectric measurements. The largest signals were obtained with 6% BT/PLA composites, probably because the BT particles at higher concentrations could not be dispersed homogeneously. Importantly the direct piezoelectric signal is large enough to power a small LCD by simply pressing a 0.2mm thick 2 cm2 area mat by a finger. We expect to use these mats in active Braille cells and in liquid crystal writing tablets.[4pt] Reference: J. Morvan, E. Buyuktanir, J.L. West, A. Jkli, ``Highly-piezoelectric Biocompatible and Soft Composite Fiber Mats,'' Appl. Phys. Lett., 100, 063901-1-4 (2012)

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

2013-03-01

426

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

427

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

NASA Astrophysics Data System (ADS)

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

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

2013-07-01

428

Electrical and structural properties of 0.98(Na0.5K0.5)NbO3-0.02LiSbO3 ceramics with ZnO content  

NASA Astrophysics Data System (ADS)

Lead-free 0.98(Na0.5K0.5)NbO3-0.02LiSbO3 (hereafter 0.98NKN-0.02LS) ceramics with the addition of ZnO were fabricated by using a conventional mixed oxide method and the effects of ZnO can test on the Electrical properties and the microstructure were investigated. Gradual changes in the electrical properties and the microstructure were observed the increasing ZnO addition. For the 0.98NKN-0.02LS+ x mol%ZnO ceramics sintered at 1100 C, the bulk density increased with the addition of ZnO and showed a maximum value at 2.0 mol% of ZnO. The Curie temperature (T c ) of the 0.98NKN-0.02LS+ x mol%ZnO ceramics increased slightly with increasing ZnO. The dielectric constant, piezoelectric constant ( d 33) and electromechanical coupling factor ( k p ) increased until small ZnO additions, which might be due to the increased density. A high piezoelectric constant (204 pC/N), electromechanical coupling factor (0.393) and dielectric constant (7138) were obtained for the 0.98NKN-0.02LS+1.0 mol%ZnO sintered at 1100 C for 4 h.

Lee, Seung-Hwan; Kim, Hyun-Ju; Lee, Young-Hie; Lee, Sung-Gap

2012-04-01

429

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

SciTech Connect

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

Mitra, Supratim; Kulkarni, Ajit R.; Prakash, Om [Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology Bombay, Mumbai 400076 (India)

2013-02-05

430

Tensile strength of fine pitch QFP lead-free soldered joints with diode laser soldering  

Microsoft Academic Search

Purpose The purpose of this paper is to investigate the laser soldering of fine pitch quad flat package (QFP) devices using lead-free solders and solder joint reliability during thermal cycling. Design\\/methodology\\/approach QFP devices were selected as the test vehicles and were soldered with four alloy types, Sn37Pb, Sn3.5Ag, Sn3.8Ag0.7Cu and Sn3.8Ag0.7Cu0.03Ce. The experimental samples were QFP-256 devices with

Peng Xue; Song-bai Xue; Liang Zhang; Yi-fu Shen; Li-li Gao; Sheng-lin Yu; Hong Zhu; Zongjie Han; Yan Chen

2011-01-01

431

Interfacial reaction between multicomponent lead-free solders and Ag, Cu, Ni, and Pd substrates  

Microsoft Academic Search

The interfacial reaction between two prototype multicomponent lead-free solders, Sn-3.4Ag-1Bi-0.7Cu-4In and Sn-3.4Ag-3Bi-0.7Cu-4In\\u000a (mass%), and Ag, Cu, Ni, and Pd substrates are studied at 250C and 150C. The microstructural characterization of the solder\\u000a bumps is carried out by scanning electron microscopy (SEM) coupled with energy dispersive x-ray analysis. Ambient temperature,\\u000a isotropic elastic properties (bulk, shear, and Youngs moduli and Poissons ratio)

G. Ghosh

2004-01-01

432

Design and characterization of piezoelectric ultrasonic motors  

NASA Astrophysics Data System (ADS)

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

Yener, Serra

433

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=548 K 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 d33~210 pC/N and low dielectric constant have lead to a very large value of piezoelectric voltage constant g33~53.910-3 Vm/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

434

Consideration of Impedance Matching Techniques for Efficient Piezoelectric Energy Harvesting  

Microsoft Academic Search

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

Hyeoungwoo Kim; Shashank Priya; Harry Stephanou; Kenji Uchino

2007-01-01

435

Cosmic ray modulation studies with Lead-Free Gulmarg Neutron Monitor  

NASA Astrophysics Data System (ADS)

A lead-free neutron monitor operating at High Altitude Research Laboratory (HARL), Gulmarg optimized for detecting 2.45 MeV neutron bursts produced during the atmospheric lightning discharges is also concurrently used for studying background neutron component present in the atmosphere. These background neutrons are produced due to the interaction of primary cosmic rays with the atmospheric constituents. In order to study and extract the information about the yield of the neutron production during transient atmospheric lightning discharges, the system is continuously operated to monitor and record the cosmic ray produced background secondary neutrons in the atmosphere. The data analysis of the background neutrons recorded by Lead-Free Gulmarg Neutron Monitor (LFGNM) has convincingly established that the modulation effects due to solar activity phenomena compare very well with those monitored by the worldwide IGY or NM64 type neutron monitors which have optimum energy response relatively towards the higher energy regime of the cosmic rays. The data has revealed various types of modulation phenomena like diurnal variation, Forbush decrease etc. during its entire operational period. However, a new kind of a periodic/seasonal variation pattern is also revealed in the data from September 2007 to September 2012, which is seen to be significantly consistent with the data recorded by Emilio Segre observatory, Israel (ESOI) Neutron Monitor. Interestingly, both these neutron monitors have comparable latitude and altitude. However, the same type of consistency is not observed in the data recorded by the other conventional neutron monitors operating across the globe.

Darzi, M. A.; Ishtiaq, P. M.; Mir, T. A.; Mufti, S.; Shah, G. N.

2014-02-01

436

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; Rdel, Jrgen [Technische Universitat Darmstadt, Germany; Kalinin, Sergei V [ORNL

2012-01-01

437

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

NASA Astrophysics Data System (ADS)

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

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

2013-08-01

438

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

439

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

NASA Astrophysics Data System (ADS)

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

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

2012-01-01

440

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

441

SEM/EDS analysis and characterization of gunshot residues from Brazilian lead-free ammunition.  

PubMed

The exposition to heavy metal-rich airborne due to fire practicing has forced to the development of heavy metal-free environmental ammunition primers all over the world. Here we characterize the GSR elements present in the Brazilian lead-free ammunition produced by Companhia Brasileira de Cartuchos (CBC) and commercialized by MagTech in the U.S. and Europe under the name CleanRange centerfire cartridges. Both first and second generations of CleanRange in calibers 9 mm Luger, .40 S&W, .380 AUTO and .38 SPL were analyzed and compared to regular Brazilian CBC ammunition by scanning electron microscopy/energy dispersive spectroscopy. Differences in composition and morphology of GSR particles from the two generations of CleanRange were observed. The first generation ammunition (found in Europe) presented spherical particles, being strontium the only unique element detected. The second generation (found in the U.S.) produced irregular particles composed mostly by potassium, aluminum, silicon and calcium. We can conclude that identification of GSR derived from CBC second generation lead-free ammunition in suspects' hands may be impossible without the addition of a distinct metallic taggant in the primer composition by the manufacturer. PMID:17764860

Martiny, Andrea; Campos, Andrea P C; Sader, Marcia S; Pinto, Andr L

2008-05-01

442

Lead-Free Low-Melting and Semiconductive Vanadate Glass Applicable to Low-Temperature Sealing  

NASA Astrophysics Data System (ADS)

We optimized the fundamental composition and additives in a semiconducting V2O5--P2O5--TeO2 glass system to develop lead-free low-melting glass suitable for low-temperature sealing below 400 C. Glass with a composition of 55.7V2O5--19.8P2O5--23.5TeO2 (mol %) has a low glass transformation temperature (Tg < 300 C) as well as hard crystallization, and it is desired as a low-temperature sealing material. The effects of adding BaO, Sb2O3, MnO2, or Fe2O3 to the fundamental composition of 55.7V2O5--19.8P2O5--23.5TeO2 (mol %) on the thermal properties and water-vapor resistance were then characterized. Adding 11.7 mol % Fe2O3 improved the water-vapor resistance drastically and decreased the thermal expansion coefficient without increasing Tg. Sealing at 360 C with our lead-free Fe2O3-added vanadate glass enabled practical airtight packaging on an electronic device.

Naito, Takashi; Aoyagi, Takuya; Sawai, Yuichi; Tachizono, Shinichi; Yoshimura, Kei; Hashiba, Yuji; Yoshimoto, Mamoru

2011-08-01

443

Assessment of circuit board surface finishes for electronic assembly with lead-free solders  

SciTech Connect

The suitability of various metallic printed wiring board surface finishes was assessed for new technology applications that incorporate assembly with Lead-free solders. The manufacture of a lead-free product necessitates elimination of lead (Pb) from the solder, the circuit board as well as the component lead termination. It is critical however for the selected interconnect Pb-free solder and the corresponding printed wiring board (PWB) and component lead finishes to be mutually compatible. Baseline compatibility of select Pb-free solders with Pb containing PWB surface finish and components was assessed. This was followed by examining the compatibility of the commercially available CASTIN{trademark} (SnAgCuSb) Pb-free solder with a series of PWB metallic finishes: Ni/Au, Ni/Pd, and Pd/Cu. The compatibility was assessed with respect to assembly performance, solder joint integrity and long term attachment reliability. Solder joint integrity and mechanical behavior of representative 50 mil pitch 20I/O SOICs was determined before and after thermal stress. Mechanical pull test studies demonstrated that the strength of SnAgCuSb solder interconnections is notably greater than that of SnPb interconnections.

Ray, U.; Artaki, I.; Finley, D.W.; Wenger, G.M. [Bell Labs., Princeton, NJ (United States). Lucent Technologies; Pan, T.; Blair, H.D.; Nicholson, J.M. [Ford Motor Co., Dearborn, MI (United States); Vianco, P.T. [Sandia National Labs., Albuquerque, NM (United States)

1996-10-01

444

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

NASA Astrophysics Data System (ADS)

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

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

445

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

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

2013-01-01