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1

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

2

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

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

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

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

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

7

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

8

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

9

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

10

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

11

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

12

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

13

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

14

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

15

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

16

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

17

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

18

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

19

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

20

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

21

(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

22

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

23

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

24

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

25

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

26

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

27

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

28

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

29

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

30

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

31

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

32

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

33

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

34

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

35

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

36

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

37

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

38

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

39

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

40

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

41

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

42

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

43

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

44

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

45

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

46

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

47

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

48

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

49

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

50

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

51

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

52

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

53

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

54

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

55

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

56

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

57

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

58

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

59

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

60

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

61

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

62

Active Noise Control Using Piezoelectric Actuators in Hard Disk Drives  

Microsoft Academic Search

With the increasing use of electromechanical microsystems, such as hard disk drives, CD-ROM drives, and DVD drives in the consumer electronics industry, there is a growing demand for quieter products. The noise emitted from these devices may originate from the vibration of mechanical components in operation, such as bearings, gears, and actuators. The vibration is then transmitted to other parts

Feng Gao; Ying Yan; Fook Fah Yap

2003-01-01

63

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

64

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

65

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

66

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

67

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

68

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

69

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

70

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

71

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

72

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

73

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

74

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

75

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

76

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

77

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

78

Vibration suppression of a hard disk driver actuator arm using piezoelectric shunt damping with a topology-optimized PZT transducer  

Microsoft Academic Search

The actuator system of a hard disk drive (HDD) is very sensitive to vibration circumstances. It is of great importance to study the dynamic characteristics of the actuator system and to control its vibration response. Piezoelectric shunt damping is an emerging vibration suppression technique used to control structural vibration. In this paper, two methods are proposed to improve vibration damping

Hao Sun; Zhichun Yang; Kai Xiang Li; Bin Li; Jiang Xie; Dan Wu; Ling Ling Zhang

2009-01-01

79

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

80

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

81

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

82

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

83

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

84

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

85

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

86

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

87

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

88

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

89

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

90

Vibration suppression of a hard disk driver actuator arm using piezoelectric shunt damping with a topology-optimized PZT transducer  

NASA Astrophysics Data System (ADS)

The actuator system of a hard disk drive (HDD) is very sensitive to vibration circumstances. It is of great importance to study the dynamic characteristics of the actuator system and to control its vibration response. Piezoelectric shunt damping is an emerging vibration suppression technique used to control structural vibration. In this paper, two methods are proposed to improve vibration damping efficiency of the classical piezoelectric shunt damping system and suppress the vibration of the actuator arm. Based on the analysis of the effect of the generalized electromechanical coupling coefficient on the amplitude of the transfer function and damping ratio, the distribution area of the PZT transducer of the shunt damping system is defined as a design variable of topology optimization to maximize the effective area and hence to maximize the converted vibration energy of the actuator arm. Moreover, the vibration control efficiency is improved by introducing a negative impedance converter to eliminate the additional loss resistance of the coil inductor of the shunt circuit. Then the vibration control experiments for the actuator arm of an HDD are carried out to verify the proposed methods. According to the results of FE analysis and modal tests of the actuator system, topology optimization for the PZT transducer is performed on the target modes while the effects of additional stiffness and additional mass of the coupled PZT transducer are also considered. The high damping efficiency of this improved piezoelectric shunt damping system is demonstrated by a 323% maximum increment of damping ratio and 20.36 dB, 8.22 dB and 12.02 dB reduction for its three modes of vibration, respectively.

Sun, Hao; Yang, Zhichun; Li, Kai Xiang; Li, Bin; Xie, Jiang; Wu, Dan; Zhang, Ling Ling

2009-06-01

91

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

92

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

93

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

94

Modeling and control of a dual stage actuator hard disk drive with piezoelectric secondary actuator  

Microsoft Academic Search

High capacity of new magnetic material can be exploited only with a fine servo-positioning of the hard disk heads. This can be achieved by means of dual stage actuation, where the secondary actuator can be realized with different technologies. In this paper, the need for a secondary actuator is proven by explicitly including the nonlinear friction on the voice coil

Roberto Oboe; Alessandro Beghi; Bruno Murari

1999-01-01

95

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

96

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

97

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

98

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

99

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

100

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

101

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

102

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

103

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

104

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

105

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

106

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

107

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

108

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

109

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

110

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

111

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

112

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

113

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

114

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

115

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

116

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

117

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

118

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

119

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

120

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

121

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

122

[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

123

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

124

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

125

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

126

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

127

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

128

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

129

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

130

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

131

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

132

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

133

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

134

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

135

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

136

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

137

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

138

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

139

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

140

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

141

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

142

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

143

High temperature indentation behavior of eutectic lead-free solder materials  

NASA Astrophysics Data System (ADS)

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

Mllera, W. H.; Worrack, H.

2010-06-01

144

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

145

Characterization of tin crystal orientation evolution during thermal cycling in lead-free solder joints  

NASA Astrophysics Data System (ADS)

To address the long term reliability of lead-free solder joints in electronic devices during thermal cycling, the fundamental understanding of deformation mechanisms was studied using polarized light optical microscopy (PLM), electron backscatter diffraction (EBSD) in scanning electron microscopy (SEM), and synchrotron X-ray diffraction (XRD). Near-eutectic Sn-3.0(wt %) Ag-0.5(wt %) Cu (SAC305) lead-free solder joints were assessed in three different package designs: low-strain plastic ball grid array (PBGA), medium-strain fine-pitch ball grid array (BGA), and high-strain wafer-level-chip-scale package (WLCSP). The effect of microstructure evolution on solder failure is correlated with dislocation slip activities. The major failure mode in lead-free solder joints during thermal cycling that causes the electrical failure of the device is cracking in the bulk Sn near the Si chip/solder interface. Microstructure and Sn grain orientation evolution usually precedes crack development. A combined approach of both statistical analysis of a large number of solder joints, and detailed studies of individual solder balls was used to investigate the causes of fracture. Sn crystal orientation evolution and its effect on deformation was characterized in solder joints with different thermal histories, and compared with those from other package designs with different effective strain levels. The relationship between the initial dominant and localized recrystallized Sn grain orientations on crack development was investigated. It is found that in the low-strain package design, cracking is strongly correlated with Sn grain orientations with the [001] direction (c-axis) nearly aligned with the chip/solder interface. But no cracks were observed in solder balls with dominant orientations that have the c-axis normal to the interface plane. In higher-strain packages, however, cracking occurred in a variety of Sn grain orientations, and even solder balls with dominant orientations that are resistant to fracture in the low-strain package design cracked. Nevertheless, at the early stage of deformation in WLCSP samples, more dramatic plastic deformation and damage was observed in a row of solder balls with similar c-axis orientations (with the [001] direction nearly aligned with the interface plane). Microstructure evolution preceding crack propagation is apparent in all package designs. Both continuous and discontinuous recrystallization processes were observed in solder joints after thermal cycling. More significant microstructure evolution and recrystallization occurred in higher strain package designs. Statistical analysis reveals that there is an increase in the number of high energy high angle grain boundaries and a decrease of low energy low angle and twin boundaries during thermal cycling. Crack propagation was facilitated by the high angle random boundaries developed during recrystallization, whereas the twin boundaries (with near 60 misorientation about the Sn [100] axis) were more resistant to cracking. The relative ease of the deformation of different Sn grain orientations also influenced crack development. Crack propagation was impeded by the hard orientations (with c -axis normal to the interface) that developed during continuous recrystallization. The gradual lattice rotation during the continuous recrystallization process is correlated with dislocation slip on facile slip systems. Local concentration of elastic strain and orientation gradients inside a continuously recrystallized grain are correlated with slip activities, and locally recovered regions may become nucleation sites for the primary recrystallization upon further straining.

Zhou, Bite

146

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

147

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

148

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.

149

Developing a self-diagnostic system for piezoelectric sensors  

Microsoft Academic Search

Measurement techniques for developing a self-diagnostic system for piezoelectric sensors are presented. The self-diagnostic system uses two types of measurement techniques based on passive and active evaluation of the piezoelectric element. Both hard and soft failures can be detected by this system. Hard failures such as loss of sensor signal and change in sensor output resistance are determined by monitoring

Patrick M. Flanagan; William J. Atherton

1990-01-01

150

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

151

Atomically Smooth Epitaxial Ferroelectric (Piezoelectric) Thin Films for the Development of a Nonvolatile, Ultrahigh Density, Fast, Low Voltage, Radiation-Hard Memory.  

National Technical Information Service (NTIS)

The goal of this research program is to develop atomically smooth, nanostructured, single crystalline, epitaxial complex oxide thin films as the basic building block for a nonvolatile, ultrahigh density, fast, low voltage, radiation-hard memory. Oxide mat...

C. H. Ahn

2003-01-01

152

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

153

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

154

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

155

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

156

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

157

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

158

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

159

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

160

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

161

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

162

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

163

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

NASA Astrophysics Data System (ADS)

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

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

2013-06-01

164

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

165

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

166

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...

167

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

168

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

169

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

170

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

171

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...

172

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

173

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

174

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

175

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

176

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

177

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

178

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

179

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

180

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

181

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

182

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

183

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

184

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

185

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

186

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

187

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

188

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

189

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

190

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

191

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

192

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

193

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

194

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

195

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

196

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

197

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

198

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

199

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

200

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

201

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

202

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

203

Developing a self-diagnostic system for piezoelectric sensors  

NASA Astrophysics Data System (ADS)

Measurement techniques for developing a self-diagnostic system for piezoelectric sensors are presented. The self-diagnostic system uses two types of measurement techniques based on passive and active evaluation of the piezoelectric element. Both hard and soft failures can be detected by this system. Hard failures such as loss of sensor signal and change in sensor output resistance are determined by monitoring the sensor's output resistance, voltage or current. These are passive measurements of the sensor's output condition. Soft failures include changes in sensor calibration and mounting conditions. Soft failures are detected by measuring structural/electrical impedance of the piezoelectric sensor. Active measurement techniques are used to calculate changes in piezoelectric element properties related to soft failures. This paper describes the general operating principles of a self-diagnostic system and discusses the design of an active/passive measurement technique required for this system to function. Experimental results using two types of piezoelectric accelerometers are presented.

Flanagan, Patrick M.; Atherton, William J.

1990-07-01

204

Developing a self-diagnostic system for piezoelectric sensors  

NASA Technical Reports Server (NTRS)

Measurement techniques for developing a self-diagnostic system for piezoelectric sensors are presented. The self-diagnostic system uses two types of measurement techniques based on passive and active evaluation of the piezoelectric element. Both hard and soft failures can be detected by this system. Hard failures such as loss of sensor signal and change in sensor output resistance are determined by monitoring the sensor's output resistance, voltage or current. These are passive measurements of the sensor's output condition. Soft failures include changes in sensor calibration and mounting conditions. Soft failures are detected by measuring structural/electrical impedance of the piezoelectric sensor. Active measurement techniques are used to calculate changes in piezoelectric element properties related to soft failures. This paper describes the general operating principles of a self-diagnostic system and discusses the design of an active/passive measurement technique required for this system to function. Experimental results using two types of piezoelectric accelerometers are presented.

Flanagan, Patrick M.; Atherton, William J.

1990-01-01

205

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

206

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

207

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

208

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

209

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

210

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

211

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

212

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

213

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

214

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

215

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

216

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

217

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

218

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

219

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

220

Piezoelectric drive circuit  

DOEpatents

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

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

1999-08-31

221

Piezoelectric drive circuit  

DOEpatents

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

Treu, C.A. Jr.

1999-08-31

222

"Mighty Worm" Piezoelectric Actuator  

NASA Technical Reports Server (NTRS)

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

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

1994-01-01

223

Low thermal stress flip-chip package for Ultra Low-k die and lead-free bumps  

Microsoft Academic Search

Reliability of Flip-Chip Ball Grid Array (FC-BGA) package greatly depends on the mechanical properties of underfill material. In the package with Ultra Low-k (ULK) die and high-lead solder bumps, low glass transition temperature (Tg) and low elastic modulus (E) are effective for ULK delaminations. However, same properties are not enough for the package with lead-free solder bumps. The lead-free solder

Y. Sawada; M. Sato; T. Abe; M. Tokunaga; S. Baba; Y. Hatanaka

2009-01-01

224

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

PubMed

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

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

2011-01-01

225

Effect of surface oxide on the melting behavior of lead-free solder nanowires and nanorods  

NASA Astrophysics Data System (ADS)

Lead-free nanosolders have shown promise in nanowire and nanoelectronics assembly. Among various important parameters, melting is the most fundamental property affecting the assembly process. Here we report that the melting behavior of tin and tin/silver nanowires and nanorods can be significantly affected by the surface oxide of nanosolders. By controlling the nanosolder reflow atmosphere using a flux, the surface oxide of the nanowires/nanorods can be effectively removed and complete nanosolder melting can be achieved. The complete melting of the nanosolders leads to the formation of nanoscale to microscale spherical solder balls, followed by Ostwald ripening phenomenon. The contact angle of the microscale solder balls formed on Si substrate was measured by direct electron microscopic imaging. These results provide new insights into micro- and nanoscale phase transition and liquid droplet coalescence from nanowires/nanorods to spheroids, and are relevant to nanoscale assembly and smaller ball grid array formation.

Gao, Fan; Rajathurai, Karunaharan; Cui, Qingzhou; Zhou, Guangwen; NkengforAcha, Irene; Gu, Zhiyong

2012-07-01

226

KNN/BNT Composite Lead-Free Films for High-Frequency Ultrasonic Transducer Applications  

PubMed Central

Lead-free K0.5Na0.5NbO3/Bi0.5Na0.5TiO3 (KNN/BNT) films have been fabricated by a composite sol-gel technique. Crystalline KNN fine powder was dispersed in the BNT precursor solution to form a composite slurry which was then spin-coated onto a platinum-buffered Si substrate. Repeated layering and vacuum infiltration were applied to produce 5-?m-thick dense composite film. By optimizing the sintering temperature, the films exhibited good dielectric and ferroelectric properties comparable to PZT films. A 193-MHz high-frequency ultrasonic transducer fabricated from this composite film showed a ?6-dB bandwidth of approximately 34%. A tungsten wire phantom was imaged to demonstrate the capability of the transducer.

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

2011-01-01

227

Analysis of primer residue from lead free ammunition by X-ray microfluorescence.  

PubMed

In forensic science, the analysis of gunshot residues was traditionally done by the detection of lead (Pb), antimony (Sb) and barium (Ba) usually found in a primer. However, the recent development of lead-free ammunition represents a new challenge for ballistic specialists. This analysis study gunshot residues from primers and ammunitions in the area surrounding bullet holes, a very important tool to determine the shooting distance. The ammunitions used were 9 mm Luger and .38 spl + p calibers, where lead in the primer was replaced with strontium (Sr) and where the lead bullet was plated with copper (Total Metal Jacket). Gunshot analysis results were obtained using an energy dispersive X-ray microfluorescence spectrometer. The method allows the detection and quantification of strontium residues on the target up to a distance of 45 cm. PMID:10782972

Charpentier, B; Desrochers, C

2000-03-01

228

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

NASA Astrophysics Data System (ADS)

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

Mohammad Alipour, Manijeh

229

Fabrication of highly oriented lead-free (Na, K)NbO 3 thin films at low temperature by Sol-Gel process  

NASA Astrophysics Data System (ADS)

Lead-free piezoelectric (Na 0.5K 0.5)NbO 3 (NKN) thin films were fabricated on SiO 2/Si substrates by sol-gel process. The NKN precursor solution was prepared from Na-ethoxide, K-ethoxide, Nb-pentaethoxide, and 2-methoxyethanol. From thermogravimetry differential thermal analysis (TG-DTA) curve of the precursor dried-gel, weight loss and exothermic peaks appeared at about 300-500 C at heating period. By using optimum fabrication conditions established from the TG-DTA, highly oriented single- phase NKN thin films were obtained at 500 C by spin-coating technique. Average grain size and root mean square roughness obtained from atomic force microscope (AFM) image of the NKN thin film sintered at 500 C were estimated to be about 250 and 8.35 nm, respectively. From TG curve, crystallinity and surface morphology, it is found that volatilization of alkaline elements seems to have been suppressible at temperature lower than 600 C.

Tanaka, Kiyotaka; Kakimoto, Ken-ichi; Ohsato, Hitoshi

2006-09-01

230

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

231

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

NASA Astrophysics Data System (ADS)

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

Ren, Fei

232

Improvement of Piezoelectricity in Piezoelectric Paper Made With Cellulose.  

National Technical Information Service (NTIS)

This report deals with the improvement of piezoelectricity in the piezoelectric paper made with cellulose. Piezoelectric paper fabrication process is composed of cellulose dissolving, wet cellulose casting, regenerating cellulose, stretching and drying pr...

J. Kim

2009-01-01

233

High performance lead free ferroelectric ATiO3/SnTiO3 superlattices  

NASA Astrophysics Data System (ADS)

Perovskite SnTiO3 (SNO) was predicted to be ferroelectric with a large spontaneous polarization. However, the perovskite phase SNO was found to be metastable in experiments. Here, we show that SNO perovskite phase can be stabilized by the interfacial geometry in ATiO3/SNO superlattices (A = Ca, Sr, Ba) of short periodicity using first principles calculations. We found that CaTiO3/SNO superlattice has the largest polarization. In all the superlattices investigated, a phase transition from tetragonal to monoclinic structure was found with increasing in-plane lattice constants. Accompanying this phase transition, polarization directions rotate from [001] to [110], which is promising for achieving large piezoelectric responses.

Zhang, Rui-Zhi; Wang, Da-Wei; Li, Fei; Ye, Hong-Jun; Wei, Xiao-Yong; Xu, Zhuo

2013-08-01

234

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

NASA Astrophysics Data System (ADS)

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

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

2012-02-01

235

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

NASA Astrophysics Data System (ADS)

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

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

2013-07-01

236

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

NASA Technical Reports Server (NTRS)

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

Sampson, Michael J.

2008-01-01

237

Microstructure and mechanical properties of new lead-free Sn-Cu-RE solder alloys  

NASA Astrophysics Data System (ADS)

The Sn-0.7%Cu alloy has been considered as a lead-free alternative to lead-tin alloys. In this work, various small amounts of rare earth (RE) elements, which are mainly Ce and La, have been added to the Sn-0.7%Cu alloy to form new solder alloys. It was found that the new alloys exhibit mechanical properties superior to that of the Sn-0.7%Cu alloy. In particular, the addition of up to 0.5% of RE elements is found to refine the effective grain size and provide a fine and uniform distribution of Cu6Sn5 in the solidified microstructure. Tensile, creep, and microhardness tests were conducted on the solder alloys. It was found that significant improvements of the tensile strength, microhardness, and creep resistance were obtained with RE element addition. Upon aging at 150C for 20 h, the microstructure of Sn-Cu-RE is more stable than that of the Sn-Cu alloy.

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

2002-09-01

238

A piezoelectric transformer  

NASA Technical Reports Server (NTRS)

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

Won, C. C.

1993-01-01

239

Kelvin and piezoelectricity  

NASA Astrophysics Data System (ADS)

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

Trainer, Matthew

2003-09-01

240

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

NASA Astrophysics Data System (ADS)

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

Sellers, Michael S.

241

Thermal Conductivity Variation with Temperature for Lead-Free Ternary Eutectic Solders  

NASA Astrophysics Data System (ADS)

The variations of the thermal conductivity with temperature for the lead-free ternary eutectic solders Bi-42.73 wt.%Sn-1.03 wt.%Ag (Bi-Sn-Ag), Sn-3.5 wt.%Ag-0.9 wt.%Cu (Sn-Ag-Cu), Sn-6 wt.%Sb-5 wt.%Ag (Sn-Sb-Ag), Sn-42.8 wt.%Bi-0.04 wt.%Cu (Sn-Bi-Cu), and In-48.4 wt.%Sn-2.31 wt.%Ag (In-Sn-Ag) were measured using a linear heat flow apparatus. It was observed that the thermal conductivities of solid phases for the Bi-Sn-Ag, Sn-Ag-Cu, Sn-Sb-Ag, Sn-Bi-Cu, and In-Sn-Ag solders decrease linearly with increasing temperature. The thermal conductivities of the Bi-Sn-Ag, Sn-Ag-Cu, Sn-Sb-Ag, Sn-Bi-Cu, and In-Sn-Ag solders at their melting temperature were obtained as 17.89 1.6 W/K-m, 49.89 4.5 W/K-m, 41.96 3.8 W/K-m, 20.03 1.8 W/K-m, and 70.21 6.3 W/K-m, respectively. The thermal temperature coefficients for the Bi-Sn-Ag, Sn-Ag-Cu, Sn-Sb-Ag, Sn-Bi-Cu, and In-Sn-Ag solders were also determined to be -2.894 10-3 K-1, -0.907 10-3 K-1, -1.246 10-3 K-1, -2.638 10-3 K-1, and -1.250 10-3 K-1, respectively, from plots of thermal conductivity versus temperature.

Aksz, Nam?k; ztrk, Esra; Bayram, mit; Aksz, Sezen; Kervan, Seluk; lgen, Ahmet; Mara?l?, Necmettin

2013-12-01

242

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

SciTech Connect

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

Rohatgi, P.K.

1996-02-01

243

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

SciTech Connect

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

Rohatgi, P.K.

1995-07-01

244

Adaptive piezoelectric shunt damping  

Microsoft Academic Search

Piezoelectric shunt damping systems reduce structural vibration by shunting an attached piezoelectric transducer with an electrical impedance. Current impedance designs result in a coupled electrical resonance at the target modal frequencies. In practical situations, variation in structural load or environmental conditions can result in significant changes in the structural resonance frequencies. This variation can severely reduce shunt damping performance as

Andrew J. Fleming; S. O. Reza Moheimani

2002-01-01

245

Adaptive piezoelectric shunt damping  

Microsoft Academic Search

Piezoelectric shunt damping systems reduce structural vibration by shunting an attached piezoelectric transducer with an electrical impedance. Current impedance designs result in a coupled electrical resonance at the target modal frequencies. In practical situations, variation in structural load or environmental conditions can result in significant changes in the structural resonance frequencies. This variation can severely reduce shunt damping performance as

A. J. Fleming; S. O. R. Moheimani

2003-01-01

246

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

247

Piezoelectricity of biopolymers.  

PubMed

The piezoelectricity of semicrystalline biopolymers was first discovered for wood and bone in the 1950's. Piezoelectric properties have since been investigated for a number of biological substances, including polysaccharides, proteins and deoxyribonucleates. The shear piezoelectric constants -d14 = d25 were determined for their oriented structures with a uniaxial symmetry Dinfinity. From studies of synthetic polypeptides and optically active polymers, it was concluded that the origin of piezoelectricity lies in the internal rotation of dipoles such as CONH. Values of d14 = -10 pC/N were determined for highly elongated films of poly-L-lactic acid, optically active and biodegradable. The implantation of this polymer induced the growth of bone, possibly because ionic current caused by piezoelectric polarization stimulated the activity of bone cells. Submicron-thick polyurea films were prepared by evaporating diisocyanate and diamine monomers in vacuum. After poling, the films exhibited pyro- and piezoelectric effects. The tensile piezoelectric constant d31 = 10 pC/N persisting up to 200 degrees C was also observed for aliphatic polyurea films. PMID:8857351

Fukada, E

1995-01-01

248

Piezoelectric cantilever sensors  

NASA Technical Reports Server (NTRS)

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

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

2008-01-01

249

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

NASA Technical Reports Server (NTRS)

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

Kessel, Kurt

2011-01-01

250

Adaptive piezoelectric sensoriactuator  

NASA Technical Reports Server (NTRS)

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

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

1996-01-01

251

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

252

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

253

Optimisation modelling for thermal fatigue reliability of lead-free interconnects in fine-pitch flip-chip packaging  

Microsoft Academic Search

Purpose This paper aims to present an integrated optimisation-modelling computational approach for virtual prototyping that helps design engineers to improve the reliability and performance of electronic components and systems through design optimisation at the early product development stage. The design methodology is used to identify the optimal design of lead-free (Sn3.9Ag0.6Cu) solder joints in fine-pitch copper column bumped flip-chip

Stoyan Stoyanov; Chris Bailey; Marc Desmulliez

2009-01-01

254

Failure mode analysis of lead-free solder joints under differential reflow profiles by high speed impact testing  

Microsoft Academic Search

The aim of this research is to investigate the mechanical behavior of lead-free solder for high speed impact. A high speed impact test was set up to measure the solder joint reliability. Differential impact speed and room temperature aging effect has been studied with Ni\\/Au substrate. Furthermore, two different solder alloys (96.5Sn-3Ag-0.5Cu, 98.5Sn-1Ag-0.5C) and three different reflow profiles are considered.

C. Y. Lin; Y. R. Chen; G. S. Shen; D. S. Liu; C. Y. Kuo; C. L. Hsu

2008-01-01

255

Investigation of Thermal-Mechanical and Moisture Driven Delamination in Lead-free QFN Packages during SMT Reflow Soldering Process  

Microsoft Academic Search

Interface delamination is one of the major failure modes in plastic IC packages. The encapsulating polymers used in electronic packaging are characteristic of high porosity, which makes the material susceptible to the moisture absorption. During reflow soldering process, the entire package is exposed to the soldering temperature as high as 260degC for lead-free solders. Under such temperatures, moisture absorbed by

Xiran Su; Haiping Luo; D. G. Yang

2006-01-01

256

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

Microsoft Academic Search

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

S. Choji; T. Sakauchi

1999-01-01

257

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

Microsoft Academic Search

Enhanced performance goals and environmental restrictions have heightened the consideration for use of alternative solders as replacements for the traditional tin-lead (Sn-Pb) eutectic and near-eutectic alloys. However, the implementation of non-Pb bearing surface finishes may lag behind solder alloy development. A study was performed which examined the effect(s) of Pb contamination on the performance of Sn-Ag-Bi and Sn-Ag-Cu-Sb lead-free solders

Paul Vianco; Jerry Rejent; I. Artaki; U. Ray; D. Finley; A. Jackson

1996-01-01

258

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

259

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

NASA Astrophysics Data System (ADS)

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

Mostofizadeh, Milad; Pippola, Juha; Frisk, Laura

2014-05-01

260

Piezoelectric Pulsed Microjets.  

National Technical Information Service (NTIS)

This reports summarizes an investigation of coupling broadband piezoelectric actuators with large force microjet actuators to achieve pulsed flow control over a broad frequency range. The development is relevant to a range of flow control problems for rot...

F. Alvi W. S. Oates

2011-01-01

261

Resonance in Piezoelectric Vibrators.  

National Technical Information Service (NTIS)

The electrical behavior of a piezoelectric vibrator leads to criteria by which to describe onset and extent of the resonance region. The equi-immittance point is convenient for delimiting the resonance range and assesses the validity of circle representat...

A. Ballato

1969-01-01

262

New Piezoelectric Polymers  

Microsoft Academic Search

Four kinds of piezoelectric polymers are introduced. Submicron thin films of polyurea are prepared by vapor deposition polymerization. Poled films of aromatic polyurea exhibit the piezoelectric constant d31=20 pC\\/N, which is almost independent of temperature in the range of 100 to 200C. Aliphatic polyureas show a ferroelectric hysteresis with a coercive field of about 100 MV\\/m. Single crystalline films of

Eiichi Fukada

1998-01-01

263

Piezoelectric Energy Harvesting Solutions  

PubMed Central

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

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

2014-01-01

264

Piezoresistive and piezoelectric MEMS strain sensors for vibration detection  

Microsoft Academic Search

Both piezoresistive and piezoelectric materials are commonly used to detect strain caused by structural vibrations in macro-scale structures. With the increasing complexity and miniaturization of modern mechanical systems such as hard disk drive suspensions, it is imperative to explore the performance of these strain sensors when their dimensions must shrink along with those of the host structures. The miniaturized strain

Stanley Kon; Kenn Oldham; Roberto Horowitz

2007-01-01

265

Acoustic metamaterials with piezoelectric resonant structures  

NASA Astrophysics Data System (ADS)

A resonant structure of a hard-core coated by piezoelectric composite materials is proposed as an acoustic metamaterial (AM), in which a negative effective mass density and elastic modulus are simultaneously achieved. The double negativity, appearing within a certain range of the filling ratio, is numerically demonstrated by the switch of the electrical boundary from open to closed. The bandwidth of the negative effective elastic modulus is sensitive to the piezoelectric constant e33. The multi-unit AM offers the advantages of broadening the double-negativity domain and of reducing the primary frequency, while the cut-up frequency remains the same as that of the single-unit cell AM.

Jin, Yabin; Bonello, Bernard; Pan, Yongdong

2014-06-01

266

Microstructure, mechanical and oxidation behavior of RE-containing lead-free solders  

NASA Astrophysics Data System (ADS)

Pb-free solders pose new challenges associated with their incorporation and reliability during service of electronic components. Recently, a new class of alloys containing rare-earth (RE) elements has been discovered. In this study, solder alloys containing lanthanum (La), cerium (Ce) and yttrium (Y) were developed and characterized. It was found that small additions of La and Ce to Sn-Ag-Cu alloys significantly improved their ductility. This has direct implications for mechanical shock and drop reliability. Microstructure characterization of solder and solder/Cu joints containing Sn-3.9Ag-0.7Cu-XRE (X = 0, 0.1, 0.5 and 2 weight percent) was conducted using optical microscopy, scanning electron microscopy and transmission electron microscopy. It was found that RE elements refined the solder microstructure. A serial-sectioning 3D reconstruction process was used to visualize the RE-containing intermetallics. Solidification of these alloys was studied using differential scanning calorimetry. The melting point of Sn-3.9Ag-0.7Cu did not change with the incorporation of RE elements. Additionally, the effect of RE content on shear and creep of lap-shear joints was studied. It was found that additions of La and Ce up to 0.5 weight percent improved the elongation of Sn-3.9Ag-0.7Cu. Y-containing alloys did not show an improvement. Creep tests were conducted at 60, 95 and 120 degrees Celsius. RE content did not markedly alter the creep behavior. Due to RE's high affinity for oxygen, oxidation of RE-containing alloys may affect their mechanical performance. Thus, the effect of 2 weight percent Ce, La or Y on the oxidation behavior was studied at 60, 95 and 130 degrees Celsius. All alloys exhibited parabolic oxidation kinetics. La and Y-containing alloys oxidized significantly faster than the Ce-containing alloy. Sn whiskering was observed to take place during oxidation, likely due to the compressive stresses developed during oxidation. Serial-sectioning with a focused ion beam followed by 3D reconstruction enabled characterization and visualization of the oxidation products. Finally, nanoindentation was employed to probe the hardness and Young's modulus of the RE-containing phases in these alloys. It was found that La and Ce intermetallics were slightly stiffer and harder than pure Sn. Y intermetallics were found to be significantly stiffer than the other phases.

Dudek, Martha A.

267

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

268

Large piezoelectric coefficient and ferroelectric nanodomain switching in Ba(Ti0.80Zr0.20)O3-0.5(Ba0.70Ca0.30)TiO3 nanofibers and thin films  

NASA Astrophysics Data System (ADS)

Currently available low-dimensional piezoelectric materials show a low piezoelectric coefficient d33 of merely 100 pm V-1 with Pb(Zr, Ti)O3-based materials at the high end. Here, we report very large piezoelectricity in Ba(Ti0.80Zr0.20)O3-0.5(Ba0.70Ca0.30)TiO3 (BTZ-0.5BCT) lead-free nanostructures sintered as thin films (d33 = 140 pm V-1) and nanofibers (d33 = 180 pm V-1). The influences of lateral size, geometry, and the clamping effect on the piezoelectric performance were investigated for both thin films and nanofibers. Combining a high piezoelectric coefficient with environmental benefits, the BTZ-0.5BCT nanostructures provide the superior functions sought for highly efficient piezoelectric devices and electromechanical systems.

Jalalian, A.; Grishin, A. M.; Wang, X. L.; Cheng, Z. X.; Dou, S. X.

2014-03-01

269

New Piezoelectric Polymers  

NASA Astrophysics Data System (ADS)

Four kinds of piezoelectric polymers are introduced. Submicron thin films of polyurea are prepared by vapor deposition polymerization. Poled films of aromatic polyurea exhibit the piezoelectric constant d31=20 pC/N, which is almost independent of temperature in the range of 100 to 200C. Aliphatic polyureas show a ferroelectric hysteresis with a coercive field of about 100 MV/m. Single crystalline films of a copolymer of vinylidene fluoride and trifluoroethylene were prepared by annealing elongated films at a paraelectric temperature range avoiding the side surface contacts. No lamella structures were present and the crystallinity was near 100%. The large electromechanical coupling factors k33=0.3 and k31=0.1 were observed. A large electrostrictive constant R=2.610-17 m2/V2 was observed for polyurethane. With a dc bias field of 15 MV/m, a piezoelectric constant of d33=600 pC/N was obtained, which was larger than that of PZT. A shear piezoelectric constant d14=-10 pC/N was obtained for oriented films of poly-L-lactic acid, which were optically active and biodegradable. After poling, this polymer showed the tensile piezoelectricity and pyroelectricity.

Fukada, Eiichi

1998-05-01

270

Effect of rare earth addition on shear strength of SnAgCu lead-free solder joints  

Microsoft Academic Search

In the present study, the effect of adding trace amount of rare earth (RE) on the shear strength of Sn3.8Ag0.7Cu lead-free\\u000a solder joints has been investigated. The shear strength of the solder joints as-reflowed and after aging at 150C for 168\\u000a and 336h was measured at a constant loading rate of 0.3mm\\/min and room temperature. The investigation indicates that the

Guangdong Li; Yaowu Shi; Hu Hao; Zhidong Xia; Yongping Lei; Fu Guo; Xiaoyan Li

2009-01-01

271

Effect of rapid solidification on mechanical properties of a lead free Sn3.5Ag solder  

Microsoft Academic Search

The melt-spinning processes of Sn3.5Ag, Sn3.5Ag2In, Sn3.5Ag2Bi and Sn3.5Ag2Zn lead free solders were investigated and analyzed. The results showed that formation of intermetallic compounds of ?-Ag3Sn, In0.2Sn0.8 and AgZn embedded in Sn matrix phase, were produced during melt-spinning technique not found under equilibrium conditions. Addition of small amount (2wt.%) In, Bi, or Zn refines the grain size, increases Hv, delay

R. M. Shalaby

2010-01-01

272

Robust Passive Piezoelectric Shunt Dampener  

Microsoft Academic Search

This paper introduces a new multiple mode passive piezoelectric shunt damping technique. The robust pas- sive piezoelectric shunt controller is capable of damping multiple structural modes and maybe less susceptible to variations in environmental conditions that can severely eect the performance of other controllers. The proposed control scheme is validated experimentally on a piezoelectric laminated plate structure.

S. Behrens; A. J. Fleming; S. O. R. Moheimani

273

Robust passive piezoelectric shunt dampener  

Microsoft Academic Search

This paper introduces a new multiple mode passive piezoelectric shunt damping technique. The robust passive piezoelectric shunt controller is capable of damping multiple structural modes and maybe less susceptible to variations in environmental conditions that can severely effect the performance of other controllers. The proposed control scheme is validated experimentally on a piezoelectric laminated plate structure.

Sam Behrens; Andrew J. Fleming; S. O. R. Moheimani

2003-01-01

274

VIBRATION EFFECT ON ROCKWELL SCALE C HARDNESS MEASUREMENT  

Microsoft Academic Search

Three ranges of Rockwell scale C reference hardness blocks: 20, 40, and 60 HRC were measured by deadweight-lever system hardness testing machine with two types of display: analog and digital. The testing machines were placed on the vibration table, whose frequency and amplitude of vibration can be controlled. Piezoelectric probe and vibration meter were used to confirm both amplitude and

Tassanai Sanponpute; Apichaya Meesaplak

275

Piezoelectric wave motor  

DOEpatents

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

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

2001-07-17

276

Piezoelectric wave motor  

DOEpatents

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

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

2003-02-11

277

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

278

Piezoelectric hydraulic pump  

NASA Astrophysics Data System (ADS)

A hybrid piezohydraulic pump is under development for smart structures applications. Structural control applications often require large force be delivered over a large displacement. Piezoelectric actuators produce a large force over a small displacement. This can be repeated many times per second. Step and repeat piezoelectric devices, such as inchworm motors, increase the power output of the actuators and have the potential to produce large forces and large displacements simultaneously. The piezohydraulic pump makes use of the step and repeat capability. The pump utilizes a piezoelectric stack actuator to drive a piston in a cylinder. The forward stroke pressurizes the hydraulic fluid in the cylinder and forces it out through a check valve. The reverse stroke draws fluid into the cylinder through a second check valve. The prototype pump has produced a working pressure of 6.9 MPa (1000 psi) and a flow rate of 45 ccm.

Mauck, Lisa D.; Lynch, Christopher S.

1999-06-01

279

Piezoelectric hydraulic pump performance  

NASA Astrophysics Data System (ADS)

A piezohydraulic pump making use of the step and repeat capability of piezoelectric actuators has been developed for actuation of aircraft control surfaces. The piezohydraulic pump utilizes a piezoelectric stack actuator to drive a piston in a cylinder. The cylinder is fitted with two check valves. On the compression stroke, oil is forced out of the cylinder. On the intake stroke, oil is drawn into the cylinder. The oil is used to drive a linear actuator. The actuator was driven at 7cm/sec with a 271N (61lb) blocking force. To achieve this, the piezoelectric stack actuator was driven at 60Hz with a switching power supply. The system utilizes an accumulator to eliminate cavitation. This work discusses piezohydraulic pumping theory, pump design, and pump performance. Consideration of pump performance includes the effects of varying accumulator pressure, hydraulic oil viscosity, and load imposed on the linear actuator.

Mauck, Lisa D.; Oates, William S.; Lynch, Christopher S.

2001-06-01

280

Piezoelectricity in polymers  

SciTech Connect

Piezoelectricity and related properties of polymers are reviewed. After presenting a historical overview of the field, the mathematical basis of piezo- and pyroelectricity is summarized. We show how the experimentally measured quantities are related to the changes in polarization and point out the serious inequlity between direct and converse piezoelectric coefficients in polymers. Theoretical models of the various origins of piezo- and pyroelectricity, which include piezoelectricity due to inhomogeneous material properties and strains, are reviewed. Relaxational effects are also considered. Experimental techniques are examined and the results for different materials are presented. Because of the considerable work in recent years polyimylidene fluoride, this polymer receives the majority of the attention. The numerous applications of piezo-and pyroelectric polymers are mentioned. This article concludes with a discussion of the possible role of piezo- and pyroelectricity in biological system.

Kepler, R.G.; Anderson, R.A.

1980-11-01

281

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

282

Piezoelectric interaction in quantum wires at low temperatures  

NASA Astrophysics Data System (ADS)

The theory of piezoelectric scattering rate and of the corresponding zero-field mobility in quantum wires has been developed under the condition of low temperature when the well known approximations of the traditional theory are hardly valid. The scattering rate and the mobility characteristics thus revealed from the present analysis are quite complex and significantly different from what the traditional theory predicts. The numerical results obtained for narrow channel wires of GaAs and ZnO, show how do the finite energy of the piezoelectric phonons and the full form of the phonon distribution bring about quite significant changes in the transport characteristics at low temperatures.

Bhattacharya, D. P.; Midday, S.; Nag, S.

2014-08-01

283

Hardness Test  

Microsoft Academic Search

\\u000a The hardness of materials is commonly characterized using indentation techniques. The hardness values depend on the tool employed\\u000a and the measured parameter, for wood, the anisotropy, heterogeneity and hygroscopicity also influence the measurements. In\\u000a this chapter, different methods used for hardness testing of wood are presented. Possible correlations between the different\\u000a hardness figures and other mechanical properties are indicated, in

Mariapaola Riggio; Maurizio Piazza

284

Design of optimized piezoelectric HDD-sliders  

NASA Astrophysics Data System (ADS)

As storage data density in hard-disk drives (HDDs) increases for constant or miniaturizing sizes, precision positioning of HDD heads becomes a more relevant issue to ensure enormous amounts of data to be properly written and read. Since the traditional single-stage voice coil motor (VCM) cannot satisfy the positioning requirement of high-density tracks per inch (TPI) HDDs, dual-stage servo systems have been proposed to overcome this matter, by using VCMs to coarsely move the HDD head while piezoelectric actuators provides fine and fast positioning. Thus, the aim of this work is to apply topology optimization method (TOM) to design novel piezoelectric HDD heads, by finding optimal placement of base-plate and piezoelectric material to high precision positioning HDD heads. Topology optimization method is a structural optimization technique that combines the finite element method (FEM) with optimization algorithms. The laminated finite element employs the MITC (mixed interpolation of tensorial components) formulation to provide accurate and reliable results. The topology optimization uses a rational approximation of material properties to vary the material properties between 'void' and 'filled' portions. The design problem consists in generating optimal structures that provide maximal displacements, appropriate structural stiffness and resonance phenomena avoidance. The requirements are achieved by applying formulations to maximize displacements, minimize structural compliance and maximize resonance frequencies. This paper presents the implementation of the algorithms and show results to confirm the feasibility of this approach.

Nakasone, Paulo H.; Yoo, Jeonghoon; Silva, Emilio C. N.

2010-03-01

285

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

286

Computational Modeling of Piezoelectric Foams  

NASA Astrophysics Data System (ADS)

Piezoelectric materials, by virtue of their unique electromechanical characteristics, have been recognized for their potential utility in many applications as sensors and actuators. However, the sensing or actuating functionality of monolithic piezoelectric materials is generally limited. The composite approach to piezoelectric materials provides a unique opportunity to access a new design space with optimal mechanical and coupled characteristics. The properties of monolithic piezoelectric materials can be enhanced via the additive approach by adding two or more constituents to create several types of piezoelectric composites or via the subtractive approach by introducing controlled porosity in the matrix materials to create porous piezoelectric materials. Such porous piezoelectrics can be tailored to demonstrate improved signal-to-noise ratio, impedance matching, and sensitivity, and thus, they can be optimized for applications such as hydrophone devices. This article captures key results from the recent developments in the field of computational modeling of novel piezoelectric foam structures. It is demonstrated that the fundamental elastic, dielectric, and piezoelectric properties of piezoelectric foam are strongly dependent on the internal structure of the foams and the material volume fraction. The highest piezoelectric coupling constants and the highest acoustic impedance are obtained in the [3-3] interconnect-free piezoelectric foam structures, while the corresponding figures of merit for the [3-1] type long-porous structure are marginally higher. Among the [3-3] type foam structures, the sparsely-packed foam structures (with longer and thicker interconnects) display higher coupling constants and acoustic impedance as compared to closepacked foam structures (with shorter and thinner interconnects). The piezoelectric charge coefficients ( d h), the hydrostatic voltage coefficients ( g h), and the hydrostatic figures of merit ( d hgh) are observed to be significantly higher for the [3-3] type piezoelectric foam structures as compared to the [3-1] type long-porous materials, and these can be enhanced significantly by modifying the aspect ratio of the porosity in the foam structures as well.

Challagulla, K. S.; Venkatesh, T. A.

2013-02-01

287

Piezoelectric ultrasonic motors: overview  

Microsoft Academic Search

This paper reviews recent developments of ultrasonic motors using piezoelectric resonant vibrations. Following the historical background, ultrasonic motors using standing and traveling waves are introduced. Driving principles and motor characteristics are explained in comparison with conventional electromagnetic motors. After a brief discussion on speed and thrust calculation, finally, reliability issues of ultrasonic motors are described.

Kenji Uchino

1998-01-01

288

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

289

Properties of Piezoelectric Materials.  

National Technical Information Service (NTIS)

The purpose of this monograph is to provide a source of data on a wide variety of piezoelectric materials which will be useful to those conducting research in this area as well as to the engineer designing ultrasonic transducers, filters, and other piezoe...

B. D. Wedlock

1964-01-01

290

PVDF piezoelectric polymer  

Microsoft Academic Search

PVDF piezo polymers are new, valuable materials for sensing and actuating applications. These materials are strong candidates for new sensors that cannot be realised with piezoceramics or single crystals. The combination of the mechanical properties of a plastic material with those of a piezoelectric material led to new sensors and transducers whose design is not easy. For this reason, the

Pierre Ueberschlag

2001-01-01

291

Piezoelectric Smart Panels for Broadband Noise Reduction  

Microsoft Academic Search

This article presents the noise reduction performance of piezoelectric smart panels featuring piezoelectric shunt damping. A piezoelectric smart panel is a plate structure on which a piezoelectric patch with an electrical shunt circuit is attached. When an incidence sound is impinged on the panel structure, the structure vibrates and the attached piezoelectric patch produces electrical energy, which is effectively dissipated

Jaehwan Kim; Young-Chae Jung

2006-01-01

292

Effects of thermomechanical cycling on lead and lead-free (SnPb and SnAgCu) surface mount solder joints  

Microsoft Academic Search

Accelerated reliability tests have been performed on leadless and leaded lead-free and lead containing SMT component assemblies. Results so far have shown that lead-free reflow soldering is a viable alternative for conventional lead based reflow soldering. The selected ternary eutectic solder alloy SnAg3.8Cu0.7 requires higher processing temperatures which could restrict the use of certain board and component types, but other

F. A. Stam; E. Davitt

2001-01-01

293

Effect of indium content and rapid solidification on microhardness and micro-creep of Sn-Zn eutectic lead free solder alloy  

Microsoft Academic Search

The Sn-Zn alloys have been considered as lead-free solders. In this paper, the effect of 0.0, 0.5, 1.0, 1.5 and 2.0 wt.% Indium as ternary additions on melting temperature, structure, microhardness and micro-creep of the Sn-9Zn lead-free solders were investigated. It is shown that the alloying additions of Indium to the Sn-Zn binary system result in a suppression of the

R. M. Shalaby

2010-01-01

294

Corrosion behaviour assessment of lead-free SnAgM (M = In, Bi, Cu) solder alloys  

Microsoft Academic Search

The corrosion behaviour of lead-free Sn88.7Ag2.3In9.0, Sn86.6Ag3.0Bi10.4, Sn96.1Ag3.1Cu0.8 and Sn90.4Ag2.9Cu6.7 solder alloys was investigated in 0.1M NaCl solution and compared with that of the conventional eutectic Sn73.9Pb26.1 solder. Scanning electron microscopy (SEM) and electron probe microanalysis (EPMA) were used to characterize the samples prior and after the electrochemical tests. Potentiodynamic polarization curves show that Sn88.7Ag2.3In9.0 and Sn86.6Ag3.0Bi10.4 solders exhibit poor

F. Rosalbino; E. Angelini; G. Zanicchi; R. Marazza

2008-01-01

295

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

296

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

PubMed

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

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

2014-05-01

297

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

NASA Astrophysics Data System (ADS)

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

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

2011-09-01

298

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

299

Origin of piezoelectricity in monolayer halogenated graphane piezoelectrics  

NASA Astrophysics Data System (ADS)

Periodic patterning with adatoms or defect is one of the methods for opening the band gap of graphene. In particular, under certain configurations controlled by the order of hydrogen and halogen atoms attached on graphene, inversion symmetry of graphene can be broken to give piezoelectricity as well as pyroelectricity. Using first-principles calculations, we examine the structural stability and electronic properties of four polar conformations of halogenated graphane (C2HX)n to understand the origin of piezoelectricity in this two-dimensional system. The formation energies and piezoelectric coefficients manifest that the four conformations of (C2HF)n are energetically stable with considerable piezoelectricity. We find that the electronic contribution of the proper piezoelectricity in (C2HF)n is mainly related to the change of the electron distribution around F atoms. By substituting flourine with chlorine, we confirm that the piezoelectricity enhances at the expense of stability degradation.

Kim, Hye Jung; Noor-A-Alam, Mohammad; Son, Jong Yeog; Shin, Young-Han

2014-05-01

300

Improper ferroelectricity and piezoelectric responses in rhombohedral (A,A')B2O6 perovskite oxides  

NASA Astrophysics Data System (ADS)

High-temperature electronic materials are in constant demand as the required operational range for various industries increases. Here we design (A,A')B2O6 perovskite oxides with [111] "rock salt" A-site cation order and predict them to be potential high-temperature piezoelectric materials. By selecting bulk perovskites which have a tendency towards only out-of-phase BO6 rotations, we avoid possible staggered ferroelectric to paraelectric phase transitions while also retaining noncentrosymmetric crystal structures necessary for ferro- and piezoelectricity. Using density functional theory calculations, we show that (La,Pr)Al2O6 and (Ce,Pr)Al2O6 display spontaneous polarizations in their polar ground state structures; we also compute the dielectric and piezoelectric constants for each phase. Additionally, we predict the critical phase transition temperatures for each material from first-principles to demonstrate that the piezoelectric responses, which are comparable to traditional lead-free piezoelectrics, should persist to high temperature. These features make the rock salt A-site-ordered aluminates candidates for high-temperature sensors, actuators, or other electronic devices.

Young, Joshua; Rondinelli, James M.

2014-05-01

301

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

302

Lead-free solder  

DOEpatents

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

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

2001-05-15

303

Evolving morphotropic phase boundary in lead-free (Bi{sub 1/2}Na{sub 1/2})TiO{sub 3}-BaTiO{sub 3} piezoceramics  

SciTech Connect

The correlation between structure and electrical properties of lead-free (1-x)(Bi{sub 1/2}Na{sub 1/2})TiO{sub 3}-xBaTiO{sub 3} (BNT-100xBT) polycrystalline piezoceramics was investigated systematically by in situ synchrotron diffraction technique, combined with electrical property characterization. It was found that the morphotropic phase boundary (MPB) between a rhombohedral and a tetragonal phase evolved into a morphotropic phase region with electric field. In the unpoled material, the MPB was positioned at the transition from space group R3m to P4mm (BNT-11BT) with optimized permittivity throughout a broad single-phase R3m composition regime. Upon poling, a range of compositions from BNT-6BT to BNT-11BT became two-phase mixture, and maximum piezoelectric coefficient was observed in BNT-7BT. It was shown that optimized electrical properties are related primarily to the capacity for domain texturing and not to phase coexistence.

Jo, Wook; Roedel, Juergen [Institute of Materials Science, Technische Universitaet Darmstadt, Petersenstr. 23, Darmstadt 64287 (Germany); Daniels, John E. [School of Materials Science and Engineering, University of New South Wales, New South Wales 2052 (Australia); Jones, Jacob L. [Department of Materials Science and Engineering, University of Florida, Gainesville, Florida 32611 (United States); Tan Xiaoli [Department of Materials Science and Engineering, Iowa State University, Ames, Iowa 50011 (United States); Thomas, Pamela A. [Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom); Damjanovic, Dragan [Ceramics Laboratory, Swiss Federal Institute of Technology (EPFL), Lausanne CH-1015 (Switzerland)

2011-01-01

304

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

305

Piezoelectric step-motion actuator  

DOEpatents

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

Mentesana; Charles P. (Leawood, KS)

2006-10-10

306

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

307

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 0.02piezoelectric applications. PMID:24219128

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

2013-11-13

308

Piezoelectricity in protein amino acids  

NASA Astrophysics Data System (ADS)

The piezoelectric activity of protein amino acids and their compounds has been measured using the pulse method at a frequency of 10 MHz. It has been established that, at room temperature, the piezoelectric effect is not observed in ?-glycine (achiral amino acid) and protein amino acids of the L modification, namely, methionine, phenylalanine, and tryptophan. An assumption has been made that this phenomenon is associated with the enhanced damping of elastic vibrations excited in samples due to the piezoelectric effect.

Lemanov, V. V.; Popov, S. N.; Pankova, G. A.

2011-06-01

309

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

310

Black branes as piezoelectrics.  

PubMed

We find a realization of linear electroelasticity theory in gravitational physics by uncovering a new response coefficient of charged black branes, exhibiting their piezoelectric behavior. Taking charged dilatonic black strings as an example and using the blackfold approach we measure their elastic and piezolectric moduli. We also use our results to draw predictions about the equilibrium condition of charged dilatonic black rings in dimensions higher than six. PMID:23368298

Armas, Jay; Gath, Jakob; Obers, Niels A

2012-12-14

311

Multilayered Unipoled Piezoelectric Transformers  

Microsoft Academic Search

This study describes a multi-layer piezoelectric voltage and power transformer which has one direction poling, operates in a wide-frequency range and delivers both step-up and step-down voltages by inverting the electrical connections. In this design, the input and output electrodes are on the same side of the disk and are isolated from each other by a fixed gap. Investigations were

Shashank Priya; Seyit Ural; Hyeoung Woo Kim; Kenji Uchino; Toru Ezaki

2004-01-01

312

Raman spectroscopy of piezoelectrics  

NASA Astrophysics Data System (ADS)

Raman spectroscopy represents an insightful characterization tool in electronics, which comprehensively suits the technological needs for locally and quantitatively assessing crystal structures, domain textures, crystallographic misalignments, and residual stresses in piezoelectric materials and related devices. Recent improvements in data processing and instrumental screening of large sampling areas have provided Raman spectroscopic evaluations with rejuvenating effectiveness and presently give spin to increasingly wider and more sophisticated experimental explorations. However, the physics underlying the Raman effect represents an issue of deep complexity and its applicative development to non-cubic crystallographic structures can yet be considered in its infancy. This review paper revisits some applicative aspects of the physics governing Raman emission from crystalline matter, exploring the possibility of disentangling the convoluted dependences of the Raman spectrum on crystal orientation and mechanical stress. Attention is paid to the technologically important class of piezoelectric materials, for which working algorithms are explicitly worked out in order to quantitatively extract both structural and mechanical information from polarized Raman spectra. Systematic characterizations of piezoelectric materials and devices are successively presented as applications of the developed equations. The Raman response of complex crystal structures, described here according to a unified formalism, is interpreted as a means for assessing both crystallographic textures and stress-related issues in the three-dimensional space (thus preserving their vectorial and tensorial nature, respectively). Statistical descriptions of domain textures based on orientation distribution functions are also developed in order to provide a link between intrinsic single-crystal data and data collected on polycrystalline (partly textured) structures. This paper aims at providing rigorous spectroscopic foundations to Raman approaches dealing with the analyses of functional behavior and structural reliability of piezoelectric devices.

Pezzotti, Giuseppe

2013-06-01

313

Modeling piezoelectric actuators  

Microsoft Academic Search

The piezoelectric actuator (PEA) is a well-known device for managing extremely small displacements in the range from 10 pm to 100 ?m. When developing a control system for a piezo-actuated positioning mechanism, the actuator dynamics have to be taken into account. An electromechanical piezo model, based on physical principles, is presented in this paper. In this model, a first-order differential

H. J. M. T. S. Adriaens; W. L. De Koning; R. Banning

2000-01-01

314

Hybrid piezoelectric energy harvesting transducer system  

NASA Technical Reports Server (NTRS)

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

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

2008-01-01

315

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

316

Hybrid input-output approach to metal production and its application to the introduction of lead-free solders.  

PubMed

The production process of metals such as copper, lead, and zinc is characterized by mutual interconnections and interdependence, as well as by the occurrence of a large number of byproducts, which include precious or rare metals, such as gold, silver, bismuth, and indium. On the basis of the framework of waste input-output (WIO), we present a hybrid 10 model that takes full account of the mutual interdependence among the metal production processes and the interdependence between them and all the other production sectors of the economy as well. The combination of a comprehensive representation of the whole national economy and the introduction of process knowledge of metal production allows for a detailed analysis of different materials-use scenarios under the consideration of full supply chain effects. For illustration, a hypothetical case study of the introduction of lead-free solder involving the production of silver as a byproduct of copper and lead smelting processes was developed and implemented using Japanese data. To meet the increased demand for the recovery and recycling of silver resources from end-of-life products, the final destination of metal silver in terms of products and user categories was estimated, and the target components with the highest silver concentration were identified. PMID:18546732

Nakamura, Shinichiro; Murakami, Shinsuke; Nakajima, Kenichi; Nagasaka, Tetsuya

2008-05-15

317

(Na, Bi)TiO3 based lead-free ferroelectric thin films on Si substrate for pyroelectric infrared sensors  

NASA Astrophysics Data System (ADS)

In this study, we report ferroelectric and pyroelectric properties of (Na0.5Bi0.5)TiO3-BaTiO3 (NBT-BT) thin films on Si substrates using chemical solution deposition for the first time. The NBT-BT thin films deposited on Pt/Ti/SiO2/Si substrates have exhibited a typical hysteresis loop with remnant polarization of 5 ?C/cm2 and coercive field of 80 kV/cm. Furthermore NBT-BT films showed pyroelectricity with pyroelectric coefficient of 0.610-8 C/cm2K. Monolithic-integration of Si electronics and lead-free ferroelectric NBT thin films has been archived using SiN passivation layer. It was previously believed that LSI processes could not incorporate any sodium-containing material which would cause characteristic degradation, such as threshold voltage shift. In this work, no threshold voltage shift in MOS characteristics was observed using this SiN layer. The SiN layer not only blocked diffusion from NBT chemistry, but also from crystallized NBT films during NBT formation process.

Akai, D.; Yoshita, R.; Ishida, M.

2013-04-01

318

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

NASA Astrophysics Data System (ADS)

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

Maleki, Milad; Cugnoni, Joel; Botsis, John

2011-10-01

319

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

NASA Astrophysics Data System (ADS)

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

Shi, Hongbin; Tian, Cuihua; Ueda, Toshitsugu

2012-05-01

320

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

SciTech Connect

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

Vianco, P.; Rejent, J. [Sandia National Labs., Albuquerque, NM (United States); Artaki, I.; Ray, U.; Finley, D.; Jackson, A. [AT and T Bell Labs., Princeton, NJ (United States)

1996-03-01

321

Vibration control of an HDD disk-spindle system utilizing piezoelectric bimorph shunt damping: I. Dynamic analysis and modeling of the shunted drive  

Microsoft Academic Search

This work proposes a new piezoelectric shunt damping methodology to control the vibration of a computer hard disk drive (HDD) disk-spindle system. The first part of this work (part I) deals with dynamic modeling of the piezoelectric shunted drive, while the second part of this work (part II) covers experimental implementation of the proposed shunt circuits. In the modeling, a

S. C. Lim; S. B. Choi

2007-01-01

322

Piezoelectric energy conversion in windmills  

Microsoft Academic Search

Theory and practice for wind generators based on piezoelectric polymers are reviewed. The basic piezoelectric equations are applied to bimorphs set into mechanical oscillation by the wind. The importance of incorporating mechanical and electrical resonance into the design is emphasized. The design and performance of two rotating generators are described, and performance is compared with theory. Design improvements are proposed,

V. H. Schmidt

1992-01-01

323

Piezoelectric Vibration Energy Harvesting Device.  

National Technical Information Service (NTIS)

A piezoelectric vibration energy harvesting device which is made up of a first mass, a second, a first spring coupled to the first mass, and a second spring coupled to the second mass. A piezoelectric element is bonded between the first mass and the secon...

K. Andic K. K. Deng

2005-01-01

324

High-Temperature Piezoelectric Sensing  

PubMed Central

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

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

2014-01-01

325

Are lead-free hunting rifle bullets as effective at killing wildlife as conventional lead bullets? A comparison based on wound size and morphology.  

PubMed

Fragmentation of the lead core of conventional wildlife hunting rifle bullets causes contamination of the target with lead. The community of scavenger species which feed on carcasses or viscera discarded by hunters are regularly exposed to these lead fragments and may die by acute or chronic lead intoxication, as demonstrated for numerous species such as white-tailed eagles (Haliaeetus albicilla) where it is among the most important sources of mortality. Not only does hunting with conventional ammunition deposit lead in considerable quantities in the environment, it also significantly delays or threatens the recovery of endangered raptor populations. Although lead-free bullets might be considered a suitable alternative that addresses the source of these problems, serious reservations have been expressed as to their ability to quickly and effectively kill a hunted animal. To assess the suitability of lead-free projectiles for hunting practice, the wounding potential of conventional bullets was compared with lead-free bullets under real life hunting conditions. Wound dimensions were regarded as good markers of the projectiles' killing potential. Wound channels in 34 killed wild ungulates were evaluated using computed tomography and post-mortem macroscopical examination. Wound diameters caused by conventional bullets did not differ significantly to those created by lead-free bullets. Similarly, the size of the maximum cross-sectional area of the wound was similar for both bullet types. Injury patterns suggested that all animals died by exsanguination. This study demonstrates that lead-free bullets are equal to conventional hunting bullets in terms of killing effectiveness and thus equally meet the welfare requirements of killing wildlife as painlessly as possible. The widespread introduction and use of lead-free bullets should be encouraged as it prevents environmental contamination with a seriously toxic pollutant and contributes to the conservation of a wide variety of threatened or endangered raptors and other members of the guild of scavengers. PMID:23186634

Trinogga, Anna; Fritsch, Guido; Hofer, Heribert; Krone, Oliver

2013-01-15

326

Piezoelectric Pushers Suppress Vibrations  

NASA Technical Reports Server (NTRS)

Vibration-suppressing control systems including piezoelectric actuators undergoing development. Small, lightweight, and rugged. Requires simpler electronic control subsystems and does not require large electromagnet coils. Continues to provide support and some passive damping even when electronic control subsystems or power supplies fail. Intended primarily to enhance safety and prevent damage in rotating machinery by sensing and counteracting vibrations. Useful in suppressing unpredictable vibrations caused by changes in loads, losses of rotating components and consequent imbalances in rotors, and ingestion of foreign objects into turbines.

Kascak, Albert F.

1990-01-01

327

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

328

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

NASA Technical Reports Server (NTRS)

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

Plante, Jeannete

2010-01-01

329

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

330

Metallurgical reactions in composite 90Pb10Sn\\/lead-free solder joints and their effect on reliability of LTCC\\/PWB assembly  

Microsoft Academic Search

Use of 90Pb10Sn solder as a noncollapsible sphere material with 95.5Sn 4Ag0.5Cu and SnInAgCu lead-free solders is investigated.\\u000a Practical reflow conditions led to strong Pb dissolution into liquid solder, resulting in >20 at.% Pb content in the original\\u000a lead-free solders. The failure mechanism of the test joints is solder cracking due to thermal fatigue, but the characteristic\\u000a lifetime of 90Pb10Sn\\/SnInAgCu

O. Nousiainen; J. Putaala; T. Kangasvieri; R. Rautioaho; J. Vhkangas

2006-01-01

331

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

332

Derivation of Piezoelectric Losses from Admittance Spectra  

Microsoft Academic Search

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

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

2009-01-01

333

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

334

Investigation Of The Effects Of Reflow Profile Parameters On Lead-free Solder Bump Volumes And Joint Integrity  

NASA Astrophysics Data System (ADS)

The electronics manufacturing industry was quick to adopt and use the Surface Mount Technology (SMT) assembly technique on realization of its huge potentials in achieving smaller, lighter and low cost product implementations. Increasing global customer demand for miniaturized electronic products is a key driver in the design, development and wide application of high-density area array package format. Electronic components and their associated solder joints have reduced in size as the miniaturization trend in packaging continues to be challenged by printing through very small stencil apertures required for fine pitch flip-chip applications. At very narrow aperture sizes, solder paste rheology becomes crucial for consistent paste withdrawal. The deposition of consistent volume of solder from pad-to-pad is fundamental to minimizing surface mount assembly defects. This study investigates the relationship between volume of solder paste deposit (VSPD) and the volume of solder bump formed (VSBF) after reflow, and the effect of reflow profile parameters on lead-free solder bump formation and the associated solder joint integrity. The study uses a fractional factorial design (FFD) of 24-1 Ramp-Soak-Spike reflow profile, with all main effects and two-way interactions estimable to determine the optimal factorial combination. The results from the study show that the percentage change in the VSPD depends on the combination of the process parameters and reliability issues could become critical as the size of solder joints soldered on the same board assembly vary greatly. Mathematical models describe the relationships among VSPD, VSBF and theoretical volume of solder paste. Some factors have main effects across the volumes and a number of interactions exist among them. These results would be useful for R&D personnel in designing and implementing newer applications with finer-pitch interconnect.

Amalu, E. H.; Lui, Y. T.; Ekere, N. N.; Bhatti, R. S.; Takyi, G.

2011-01-01

335

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

SciTech Connect

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

Amini, Rasool, E-mail: amini@sutech.ac.ir [Department of Materials Science and Engineering, Shiraz University of Technology, 71557-13876 Shiraz (Iran, Islamic Republic of)] [Department of Materials Science and Engineering, Shiraz University of Technology, 71557-13876 Shiraz (Iran, Islamic Republic of); Ghazanfari, Mohammad Reza; Alizadeh, Morteza; Ardakani, Hamed Ahmadi [Department of Materials Science and Engineering, Shiraz University of Technology, 71557-13876 Shiraz (Iran, Islamic Republic of)] [Department of Materials Science and Engineering, Shiraz University of Technology, 71557-13876 Shiraz (Iran, Islamic Republic of); Ghaffari, Mohammad [Department of Electrical and Electronics Engineering, UNAMNational Institute of Materials Science and Nanotechnology, Bilkent University, Ankara 06800 (Turkey)] [Department of Electrical and Electronics Engineering, UNAMNational Institute of Materials Science and Nanotechnology, Bilkent University, Ankara 06800 (Turkey)

2013-02-15

336

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

337

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

338

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

339

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

340

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

341

Design Requirements for Amorphous Piezoelectric Polymers  

NASA Technical Reports Server (NTRS)

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

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

1999-01-01

342

Development of lead-free copper alloy graphite castings. Annual report for the period January through December 1996  

SciTech Connect

Centrifugal casting of Copper alloys containing graphite particles established the feasibility of making hollow cylindrical castings. In theses castings, the graphite particles are segregated to the inner periphery making them well suited for bearing applications because of the lubricity of the graphite particles. The recovery of graphite is found to be around 90%. Chemical analysis shows that the average concentration of graphite particles near the inner periphery is 13 vol.% (3.5 wt.%) and 16.3 vol.% (4.54 wt.%) for castings made from melts originally containing 7 vol.% (2 wt.%) and 13 vol.% (3.5 wt. %) graphite particles, respectively. Hardness tests show that as the volume fraction of graphite particles increases, the hardness values in the graphite rich zone is found to be widely scattered. The results indicate that it is feasible to centrifugally cast copper alloys containing dispersed graphite particles to produce cylindrical components with graphite rich inner periphery for bearing and plumbing applications.

Rohatgi, P.K.

1997-03-01

343

Radiation tolerance of piezoelectric bulk single-crystal aluminum nitride.  

PubMed

For practical use in harsh radiation environments, we pose selection criteria for piezoelectric materials for non-destructive evaluation (NDE) and material characterization. Using these criteria, piezoelectric aluminum nitride is shown to be an excellent candidate. The results of tests on an aluminum-nitride- based transducer operating in a nuclear reactor are also presented. We demonstrate the tolerance of single-crystal piezoelectric aluminum nitride after fast and thermal neutron fluences of 1.85 x 10(18) neutron/cm(2) and 5.8 x 10(18) neutron/ cm(2), respectively, and a gamma dose of 26.8 MGy. The radiation hardness of AlN is most evident from the unaltered piezoelectric coefficient d33, which measured 5.5 pC/N after a fast and thermal neutron exposure in a nuclear reactor core for over 120 MWh, in agreement with the published literature value. The results offer potential for improving reactor safety and furthering the understanding of radiation effects on materials by enabling structural health monitoring and NDE in spite of the high levels of radiation and high temperatures, which are known to destroy typical commercial ultrasonic transducers. PMID:24960710

Parks, David; Tittmann, Bernhard

2014-07-01

344

Dielectric Properties of Piezoelectric Polyimides  

NASA Technical Reports Server (NTRS)

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

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

1997-01-01

345

Piezoelectric Rotary Tube Motor  

NASA Technical Reports Server (NTRS)

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

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

2011-01-01

346

New Pyroelectric Contributions to Piezoelectricity.  

National Technical Information Service (NTIS)

The authors show that the Voigt constitutive equations, the traditional algebraic proof of the equality of the direct and converse piezoelectric effects, and the usual neglect of the magnetic field are incorrect in pyroelectrics. A measurement of vector H...

D. F. Nelson M. Lax

1973-01-01

347

Piezoelectricity: Venerable Effect, Modern Thrusts.  

National Technical Information Service (NTIS)

A synopsis of the piezoelectric effect is presented in the context of its history, traditional uses, and relation to crystal symmetry. Associated effects are briefly noted. Future prospects, particularly in the area of microelectromechanical systems/struc...

A. Ballato

1994-01-01

348

Polymeric piezoelectric acoustic semicircular transducers  

NASA Astrophysics Data System (ADS)

In commercial applications it is important to be able to either cancel noise, such as in the cabin of a combine, or to generate audible noise, such as in the case of an alarm. Piezoelectrics have demonstrated promise for active noise control and sound generation applications. In this investigation, the dynamic and acoustic capabilities of polymer piezoelectric semi-circular transducers were studied for such applications. The dynamic response of semi-circular piezoelectric transducers was determined numerically using the general purpose finite element code ABAQUS, then verified analytically and experimentally. The acoustic response was modeled using the commercial code COMET/Acoustics with the dynamic velocity response calculated by ABAQUS as initial boundary conditions. Experimental studies were performed on fixed-fixed polymeric piezoelectric curved transducers. The sensitivity of the sound generation capabilities of the transducer was investigated with respect to variations in radius, thickness and width parameters to demonstrate the potential of these devices for noise cancellation and audible sound applications.

Bailo, Kelly C.; Brei, Diann E.; Grosh, Karl

1998-07-01

349

Piezoelectric One-Way Remote  

NSDL National Science Digital Library

In this activity, learners construct a device out of a piezoelectric igniter, like those used as barbecue lighters. Learners use the device to remotely start current flowing in a simple series circuit containing a small electric fan.

Rathjen, Don

2004-01-01

350

Evaluation of the oven reflow bonding and flip chip bonder bonding of lead free Sn0.7Cu solder bumped die on low-cost FR4 substrate for flip-chip applications  

Microsoft Academic Search

With the increased awareness of the lead free solder in the electronic packaging industry, the development of the lead free solder on the low-cost FR-4 substrate is a necessary for the flip-chip applications. However, it is found that the high reflow temperature of the lead free solders (normally >250C) caused substrate burnt related defects in the FR-4 substrates (TB <20O0C)

Esther W. C. Yau; D. F. W. Hong; Philip C. H. Chan

2003-01-01

351

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

352

Piezoelectrically Initiated Pyrotechnic Igniter  

NASA Technical Reports Server (NTRS)

This innovation consists of a pyrotechnic initiator and piezoelectric initiation system. The device will be capable of being initiated mechanically; resisting initiation by EMF, RF, and EMI (electromagnetic field, radio frequency, and electromagnetic interference, respectively); and initiating in water environments and space environments. Current devices of this nature are initiated by the mechanical action of a firing pin against a primer. Primers historically are prone to failure. These failures are commonly known as misfires or hang-fires. In many cases, the primer shows the dent where the firing pin struck the primer, but the primer failed to fire. In devices such as "T" handles, which are commonly used to initiate the blowout of canopies, loss of function of the device may result in loss of crew. In devices such as flares or smoke generators, failure can result in failure to spot a downed pilot. The piezoelectrically initiated ignition system consists of a pyrotechnic device that plugs into a mechanical system (activator), which on activation, generates a high-voltage spark. The activator, when released, will strike a stack of electrically linked piezo crystals, generating a high-voltage, low-amperage current that is then conducted to the pyro-initiator. Within the initiator, an electrode releases a spark that passes through a pyrotechnic first-fire mixture, causing it to combust. The combustion of the first-fire initiates a primary pyrotechnic or explosive powder. If used in a "T" handle, the primary would ramp the speed of burn up to the speed of sound, generating a shock wave that would cause a high explosive to go "high order." In a flare or smoke generator, the secondary would produce the heat necessary to ignite the pyrotechnic mixture. The piezo activator subsystem is redundant in that a second stack of crystals would be struck at the same time with the same activation force, doubling the probability of a first strike spark generation. If the first activation fails to ignite, the device is capable of multiple attempts. Another unique aspect is in the design of the pyrotechnic device. There is an electrode that aids the generation of a directed spark and the use of a conductive matrix to support the first-fire material so that the spark will penetrate to the second electrode.

Quince, Asia; Dutton, Maureen; Hicks, Robert; Burnham, Karen

2013-01-01

353

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

354

Large converse magnetoelectric effect in Na0.5Bi0.5TiO3-CoFe2O4 lead-free multiferroic composites  

NASA Astrophysics Data System (ADS)

Lead-free multiferroic composites of ferroelectric, Na0.5Bi0.5TiO3 (NBT) and ferrimagnetic, CoFe2O4 (CFO) were synthesized by the solid-state sintering method and a systematic study of structural, magnetic, and magnetoelectric properties was undertaken. X-ray diffraction and field emission scanning electron microscopy displayed the formation of single phase for parent phases and the presence of both phases in the composites. Magnetic properties were investigated using a vibrating sample magnetometer (VSM) and ferromagnetic resonance (FMR) measurements at room temperature. Strong magnetoelectric (ME) coupling was demonstrated by an electric field tunable FMR field shift. A large value of converse ME coefficient 109 Oe-cm kV-1 was observed for NBT/CFO 70/30 composite. Furthermore, these lead-free multiferroic composites exhibiting a large converse magnetoelectric effect at room temperature provide great opportunities for electrostatically tunable devices at microwave frequencies.

Narendra Babu, S.; Malkinski, Leszek

2012-04-01

355

Effect of isothermal aging and salt spray tests on reliability and mechanical strength of eutectic Sn-Bi lead-free solder joints  

Microsoft Academic Search

Eutectic Sn-Bi solder has attracted a great deal of interest since it offers good reliability comparable to that of Sn-Pb solders. Additionally, the increasing need for low cost manufacturing processes, particularly in consumer electronics, has made it an interesting alternative. This paper presents reliability and microstructural studies of eutectic 42%Sn58%Bi (wt.%) lead-free solder alloy. The reliability was investigated using two

M. Mostofizadeh; J. Pippola; T. Marttila; L. Frisk

2012-01-01

356

Prediction of stress-strain relationship with an improved Anand constitutive Model For lead-free solder Sn3.5Ag  

Microsoft Academic Search

An improved Anand constitutive model is proposed to describe the inelastic deformation of lead-free solder Sn-3.5Ag used in solder joints of microelectronic packaging. The new model accurately predicted the overall trend of steady-state stress-strain behavior of the solder for the temperature range from 233 K to 398 K and the strain rate range from 0.005 s-1 to 0.1 s-1. h0,

Xu Chen; Gang Chen; Masao Sakane

2005-01-01

357

Development and evaluation of lead free reflow soldering techniques for the flip chip bonding of large GaAs pixel detectors on Si readout chip  

Microsoft Academic Search

Lead free reflow soldering techniques applying AuSn as well as SnAg electroplated bumps were chosen for the evaluation of the flip chip bonding process for a x-ray pixel detector. Both can be used in pick & place processes with a subsequent batch reflow suitable for high volume production. AuSn solder was selected due to its fluxless bondability, the good wettability

M. Klein; M. Hutter; H. Oppermann; T. Fritzsch; G. Engelmann; L. Dietrich; J. Wolf; B. Bramer; R. Dudek; H. Reichl

2008-01-01

358

Effects of Ga, Al, Ag, and Ce multi-additions on the wetting characteristics of Sn9Zn lead-free solder  

Microsoft Academic Search

An orthogonal method was used to evaluate the effects of Ga, Al, Ag, and Ce multi-additions on the wetting characteristics\\u000a of Sn-9Zn lead-free solders by wetting balance method. The results show that the optimal loading of Ga, Al, Ag, and Ce was\\u000a 0.2 wt.%, 0.002 wt.%, 0.25 wt.%, and 0.15 wt.%, respectively. Intermetallic compounds (IMCs) formed at the interface between

Hui Wang; Songbai Xue; Feng Zhao; Wenxue Chen

2009-01-01

359

Effect of Bi addition on the activation energy for the growth of Cu 5Zn 8 intermetallic in the SnZn lead-free solder  

Microsoft Academic Search

The growth kinetics of Cu5Zn8 phase has been investigated under long-term thermal exposure conditions using single shear lap joints. The Cu5Zn8 phase was formed by reacting SnZn and SnZnBi lead-free solders with Cu substrate. A scanning electron microscope (SEM) was used to observe the morphology of the phases and energy dispersive X-ray (EDX) was used to estimate the elemental compositions

Ramani Mayappan; Zainal Arifin Ahmad

2010-01-01

360

Final report of the key comparison CCQM-K88: Determination of lead in lead-free solder containing silver and copper  

NASA Astrophysics Data System (ADS)

The CCQM-K88 key comparison was organized by the Inorganic Analysis Working Group of CCQM to test the abilities of the national metrology institutes to measure the mass fraction of lead in lead-free solder containing silver and copper. National Metrology Institute of Japan (NMIJ), National Institute of Metrology of China (NIM) and Korea Research Institute of Standards and Science (KRISS) acted as the coordinating laboratories. The participants used different measurement methods, though most of them used inductively coupled plasma optical emission spectrometry (ICP-OES) or isotope-dilution inductively coupled plasma mass spectrometry (ID-ICP-MS). Accounting for relative expanded uncertainty, comparability of measurement results was successfully demonstrated by the participating NMIs for the measurement of the mass fraction of lead in lead-free solder at the level of 200 mg/kg. It is expected that metals at mass fractions greater than approximately 100 mg/kg in lead-free solder containing silver and copper can be determined by each participant using the same technique(s) employed for this key comparison to achieve similar uncertainties mentioned in the present report. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Hioki, Akiharu; Nonose, Naoko; Liandi, Ma; Jingbo, Chao; Liuxing, Feng; Chao, Wei; Haeng Cho, Kyung; Suh, Jung Ki; Min, Hyung Sik; Lim, Youngran; Recknagel, Sebastian; Koenig, Maren; Vogl, Jochen; Caciano de Sena, Rodrigo; dos Reis, Lindomar Augusto; Borinsky, Mnica; Puelles, Mabel; Hatamleh, Nadia; Acosta, Osvaldo; Turk, Gregory; Rabb, Savelas; Sturgeon, Ralph; Methven, Brad; Rienitz, Olaf; Jaehrling, Reinhard; Konopelko, L. A.; Kustikov, Yu A.; Kozyreva, S. B.; Korzh, A. A.

2013-01-01

361

Wideband piezoelectric pressure transducer  

NASA Astrophysics Data System (ADS)

A piezoelectric pressure transducer for pressures of up to 100 MPa was developed, with an operating frequency range from 100 Hz to 1 MHz on the electrical side - sufficiently wide to reproduce pressure profiles of arc discharges with microsecond rise times and millisecond fall times. The sensing element is a disk of TsTS-19 piezoceramic material, 1 mm thick and 5 mm in diameter. It is thermally and electrically insulated from the arc plasma by a compound transmission rod consisting of two quartz crystals 5 mm in diameter and freely sliding inside a teflon sleeve. The 50 mm long waveguide for absorbing acoustic vibrations and thus separating the valid signal from the reflected one consists of brass wires acoustically insulated with epoxy resin and encapsulated into a textolite sleeve with epoxy resin at the other end. A copper housing shields the transducer from electromagnetic interference. The transducer output signal passes through a matching circuit and then a high-impedance voltage divider to a differential amplifier, the latter being shunted by a stabilizing low 1 Mohm resistance at the input. A special feature of this transducer is low-frequency compensation by means of a corrective RC-circuit. After calibration of oscillograms, the transducer has a sensitivity of 1 V/MPa over the 10(-2) to 10 MPa range. Its resolution corresponds to the 2 microsecond maximum rise time of its output signal, with the sensing element located at the end of a shock tube.

Godonyuk, V. A.; Zhuravlev, B. V.; Shedko, I. P.

1986-02-01

362

Cryogenic Piezoelectric Actuator  

NASA Technical Reports Server (NTRS)

In this paper, PMN-PT single crystal piezoelectric stack actuators and flextensional actuators were designed, prototyped and characterized for space optics applications. Single crystal stack actuators with footprint of 10 mm x10 mm and the height of 50 mm were assembled using 10 mm x10mm x0.15mm PMN-PT plates. These actuators showed stroke > 65 - 85 microns at 150 V at room temperature, and > 30 microns stroke at 77 K. Flextensional actuators with dimension of 10mm x 5 mm x 7.6 mm showed stroke of >50 microns at room temperature at driving voltage of 150 V. A flextensional stack actuator with dimension of 10 mm x 5 mm x 47 mm showed stroke of approx. 285 microns at 150 V at room temperature and > 100 microns at 77K under driving of 150 V should be expected. The large cryogenic stroke and high precision of these actuators are promising for cryogenic optics applications.

Jiang, Xiaoning; Cook, William B.; Hackenberger, Wesley S.

2009-01-01

363

Integrated wireless piezoelectric sensors  

NASA Astrophysics Data System (ADS)

Piezoelectric sensor arrays and sensor networks have been suggested as a means to monitor the integrity of composite structures throughout the service life for instance of an aircraft. Complex sensor systems will require significant additional expenditures with respect to cabling and electronics, with the added weight and effort possibly outweighing any benefits. Sensor positions in remote locations of an aircraft will often necessitate accessibility to these locations for maintenance purposes. For these reasons wireless, integrated sensors have recently become an object of increasing interest. Within the framework of a feasibility study various aspects of integrated wireless sensor system were investigated in detail. Particular emphasis was thereby laid on issues that are essential form a practical point of view, but that have not been discussed in the literature extensively. As a starting point a trade-off study between different sensor network configurations was conducted, form passive, remotely queried senors without power supply to fully functional active sensor pads with integrated power supply and electronics. Various concepts for the on-board energy supply of remotely queried sensor pads were studied and a comparison between rechargeable, and single-use batteries was performed. The suitability of different electronic components for integration into carbon fiber composites was investigated with particular emphasis on their survivability under typical temperature cycles experienced in autoclave runs. Finally, a crackwire sensor as an example of a passive remotely queried sensor system was pursued further in order to show the feasibility of such a wireless system for composite health monitoring purposes.

Ihler, Elmar; Zaglauer, Helmut W.; Herold-Schmidt, Ursula; Dittrich, Kai W.; Wiesbeck, Werner

2000-06-01

364

Multimodal passive vibration suppression with piezoelectrics  

NASA Astrophysics Data System (ADS)

Passive piezoelectric damping devices are studied. These devices, consisting of a piezoelectric element and a resonant shunt, are analogous to mechanical damped vibration absorbers. In the past, a single piezoelectric device has been used to suppress a single structural mode. In this paper, the theory is expanded so that a single piezoelectric element can be used to suppress multiple modes. The multimode damper is demonstrated experimentally as a two-mode device applied to a cantilevered beam.

Hollkamp, Joseph J.

1993-04-01

365

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

366

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

367

Piezoelectric Properties of Triglycine-Sulphate  

Microsoft Academic Search

Since triglycine sulphate crystal is centrosymmetric above the Curie point, the piezoelectricity in the ferroelectric phase is expected to be an ``induced'' one as in the case of barium titanate, distinct from an ``intrinsic'' piezoelectricity of rochelle salt. Temperature dependences of piezoelectric constants are measured by using various cuts of crystal, and some experiments on electrostrictive effect above the Curie

Takuro Ikeda; Yoichi Tanaka; Hiroo Toyoda

1962-01-01

368

Parameter identification method for piezoelectric shunt damping  

Microsoft Academic Search

Piezoelectric shunt damping is a method to reduce structural vibration by shunting a piezoelectric element with an electrical circuit. This paper proposes a method to identify the physical parameters that are required to design piezoelectric shunt damping systems. Employing self-sensing actuator methodology, the proposed method requires no additional sensor or actuator other than a simple bridge circuit. The parameters can

Kentaro Takagi; Kenji Nagase; Kazuhiko Oshima; Yoshikazu Hayakawa; Zhi-Wei Luo

2004-01-01

369

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

370

Recent developments of polar piezoelectric polymers  

Microsoft Academic Search

Following the extensive studies on the piezoelectric, pyroelectric and ferroelectric properties of polyvinylidene fluoride and its copolymers, a vast number of polymers were investigated for these properties. Piezoelectric thin films of polyurea were prepared by vapor deposition polymerization in vacuum and stable up to 200 degC. Piezoelectric odd nylon was characterized by the field induced rotation of amide dipoles in

Eiichi Fukada

2006-01-01

371

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

372

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

373

Electronics for Piezoelectric Smart Structures  

NASA Technical Reports Server (NTRS)

This paper briefly presents work addressing some of the basic considerations for the electronic components used in smart structures incorporating piezoelectric elements. After general remarks on the application of piezoelectric elements to the problem of structural vibration control, three main topics are described. Work to date on the development of techniques for embedding electronic components within structural parts is presented, followed by a description of the power flow and dissipation requirements of those components. Finally current work on the development of electronic circuits for use in an 'active wall' for acoustic noise is introduced.

Warkentin, D. J.; Tani, J.

1997-01-01

374

Triple-scale analysis and fabrication of new biocompatible MgSiO3 piezoelectric thin films  

NASA Astrophysics Data System (ADS)

Recently, the lead free piezoelectric material, which should be used for medical devices, such as health monitoring system (HMS) and drug delivery system (DDS), is strongly required. In this study, we discovered a newly designed MgSiO3 thin film, as a biocompatible piezoelectric actuator, by using the first-principles calculation and process crystallography simulation algorithm. At first, crystal structure was calculated by using the first-principles density functional theory. Secondly, the best substrate for MgSiO3 was searched by using the process crystallography simulation. Next, MgSiO3 thin film was generated in our laboratory by using the RF magnetron sputtering apparatus. Finally, crystallographic orientation was obtained by using X-ray diffractometer and the piezoelectric property of thin film was measured by the ferroelectric measurement system. As a result, lattice parameters of MgSiO3 with tetragonal structure were obtained as a=b=0.3449nm and c=0.3538nm, and its aspect ratio was 1.026. Au(111) was chosen as the best substrate, on which MgSiO3 thin film with minimum total energy could be grown. Then, MgSiO3(111) was generated on Au(111)/SrTiO3(110) by using the RF magnetron sputtering apparatus. The piezoelectric strain constant d33 of MgSiO3 thin film generated at 400C was measured as 219.8pm/V and it was higher than one of the existing piezoelectric material BaTiO3. Consequently, we succeeded the generation of a new biocompatible MgSiO3 piezoelectric thin film, which can be applied to medical devices in the future.

Hwang, Hwisim; Uetsuji, Yasutomo; Katayama, Tsutao; Nakamachi, Eiji

2010-03-01

375

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

376

Thin Film Piezoelectrics for MEMS  

Microsoft Academic Search

Thin film piezoelectric materials offer a number of advantages in microelectromechanical systems (MEMS), due to the large motions that can be generated, often with low hysteresis, the high available energy densities, as well as high sensitivity sensors with wide dynamic ranges, and low power requirements. This paper reviews the literature in this field, with an emphasis on the factors that

S. Trolier-McKinstry; P. Muralt

2004-01-01

377

Cylindrical Piezoelectric Fiber Composite Actuators  

NASA Technical Reports Server (NTRS)

The use of piezoelectric devices has become widespread since Pierre and Jacques Curie discovered the piezoelectric effect in 1880. Examples of current applications of piezoelectric devices include ultrasonic transducers, micro-positioning devices, buzzers, strain sensors, and clocks. The invention of such lightweight, relatively inexpensive piezoceramic-fiber-composite actuators as macro fiber composite (MFC) actuators has made it possible to obtain strains and displacements greater than those that could be generated by prior actuators based on monolithic piezoceramic sheet materials. MFC actuators are flat, flexible actuators designed for bonding to structures to apply or detect strains. Bonding multiple layers of MFC actuators together could increase force capability, but not strain or displacement capability. Cylindrical piezoelectric fiber composite (CPFC) actuators have been invented as alternatives to MFC actuators for applications in which greater forces and/or strains or displacements may be required. In essence, a CPFC actuator is an MFC or other piezoceramic fiber composite actuator fabricated in a cylindrical instead of its conventional flat shape. Cylindrical is used here in the general sense, encompassing shapes that can have circular, elliptical, rectangular or other cross-sectional shapes in the planes perpendicular to their longitudinal axes.

Allison, Sidney G.; Shams, Qamar A.; Fox, Robert L.

2008-01-01

378

Ultrasonic clutch using piezoelectric vibrators  

Microsoft Academic Search

This paper investigates the design, fabrication and test of an ultrasonic clutch with two piezoelectric vibrators, which is driven by the phenomenon of ultrasonic levitation. For the vibrators, one is used as a driving member connected to a shaft of a driving motor, and the other is used as a slave member connected to a shaft of a mechanical load.

Kuo-Tsai Chang

2004-01-01

379

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

380

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

381

Significant second-harmonic generation in two lead-free polar oxides BiInO3 and BiAlO3: A first-principles investigation  

Microsoft Academic Search

Density functional theory with the generalized gradient approximation is applied to study the second-harmonic generation (SHG) in two lead-free polar oxides BiInO3 and BiAlO3. Significant SHG susceptibilities, larger than 500 (10-9 esu), are revealed in both of them. The low frequency limit is found to reach 13 (10-9 esu) and 43 (10-9 esu) for BiInO3 and BiAlO3, respectively. In the

Sheng Ju; Tian-Yi Cai

2009-01-01

382

High Power Piezoelectric Characterization for Piezoelectric Transformer Development  

NASA Astrophysics Data System (ADS)

The major goal was to develop characterization techniques to identify and define guidelines to manufacture high power density actuators. We particularly aim at improving the strengths of piezoelectric transformers, namely the high efficiency, ease of manufacturing, low electromagnetic noise, and high power to weight ratio resulting in an adaptor application by identifying material limitations, geometrical limitations and offer guidelines to counter drawbacks limiting the power density. There are 3 losses present in piezoelectrics. Namely dielectric, elastic and piezoelectric losses. These losses can be calculated using mechanical quality factors of the resonating piezoelectric actuator. But in order to calculate all three losses, the mechanical quality factor for resonance and anti resonance need to be measured. Although the mechanical quality factor for resonance is conventionally measured, measurements in antiresonance have been ignored. Since there was no unique measurement technique to address antiresonance and resonance Q in one single sweep, in this study constant vibration velocity method was developed. During the constant vibration velocity measurement, the input electrical energy is monitored and significant differences between resonance and antiresonance drives are observed. For the same output work (identical vibration velocity) significant differences in the losses were observed. Thermographic images have shown increasing temperature differences for resonance and antiresonance nodal point temperatures, with higher vibration velocities. The theoretical evaluation identified the difference observed in the mechanical quality factors at resonance and antiresonance to stem from the piezoelectric loss. In order to investigate losses in the absence of thermal effects a transient characterization technique was adopted. The burst technique, originally developed for characterization of the mechanical quality factor at resonance, has been modified with a switch circuit to leave the resonator in an open circuit condition. The newly introduced open circuits burst have resulted in antiresonance quality factor measurements along with resonance quality factors in a "non-heating" sample. In this technique too, resonance and antiresonance losses showed significant difference. Resonance burst mode characterizations at elevated ambient temperatures have shown that the lower vibration velocity mechanical quality factors appear to be more sensitive to the ambient temperature. Design criteria's to produce the most power dense structure were investigated. Common device shapes were investigated to see which one does enhance the power density of the piezoelectric device. Disk shaped piezoelectric actuators have proven to have lower matching impedances and higher, farther persisting mechanical quality factors with respect to vibration velocities. In order to achieve identical power level, plate shaped samples will have been to strain ~3.5 times more than disk shaped samples. Thus the most power dense structure has been concluded to be a disk shape ~1W/cm3 Once the actuators shape was fixed, further design on structure were conducted with (c)ATILA finite element method. For the transformer application, the design considered following key factors; 1-Controlling the output impedance by optimizing number of layers and layer thicknesses of the multilayer and 2- Evaluation of various electrodes and their affect on high power performance was evaluated. As the thickness of active layers decreased, the number of electrode layers increases. This increase in the metal to piezoelectric ratio and the relative increase in the electrode resistance under high current loads, both will have to be accounted for. Thus; with the piezoelectric composition and the device structure optimized, the research input electrical power. Once the actuators shape was fixed, further design on structure were conducted with (c)ATILA finite element method. For the transformer application, the design considered following key factors; 1-Controlling the output imped

Ural, Seyit O.

383

Coefficients of thermal expansion for single crystal piezoelectric fiber composites  

Microsoft Academic Search

Piezoelectric fiber composites were developed to overcome drawbacks of typical monolithic piezoceramic (PZT) actuators. Although piezoelectric fiber composites had many improvements over the monolithic PZT, there are still improvements. Thus, the single crystal piezoelectric fiber composite actuator is proposed. Single crystal piezoelectric materials such as PMN-PT have larger piezoelectric strain constants, higher bandwidth and higher energy density than polycrystalline counterparts.

Jae-Sang Park; Ji-Hwan Kim

2007-01-01

384

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

385

Virus-based piezoelectric energy generation  

NASA Astrophysics Data System (ADS)

Piezoelectric materials can convert mechanical energy into electrical energy, and piezoelectric devices made of a variety of inorganic materials and organic polymers have been demonstrated. However, synthesizing such materials often requires toxic starting compounds, harsh conditions and/or complex procedures. Previously, it was shown that hierarchically organized natural materials such as bones, collagen fibrils and peptide nanotubes can display piezoelectric properties. Here, we demonstrate that the piezoelectric and liquid-crystalline properties of M13 bacteriophage (phage) can be used to generate electrical energy. Using piezoresponse force microscopy, we characterize the structure-dependent piezoelectric properties of the phage at the molecular level. We then show that self-assembled thin films of phage can exhibit piezoelectric strengths of up to 7.8 pm V-1. We also demonstrate that it is possible to modulate the dipole strength of the phage, hence tuning the piezoelectric response, by genetically engineering the major coat proteins of the phage. Finally, we develop a phage-based piezoelectric generator that produces up to 6 nA of current and 400 mV of potential and use it to operate a liquid-crystal display. Because biotechnology techniques enable large-scale production of genetically modified phages, phage-based piezoelectric materials potentially offer a simple and environmentally friendly approach to piezoelectric energy generation.

Lee, Byung Yang; Zhang, Jinxing; Zueger, Chris; Chung, Woo-Jae; Yoo, So Young; Wang, Eddie; Meyer, Joel; Ramesh, Ramamoorthy; Lee, Seung-Wuk

2012-06-01

386

Piezoelectric Power Requirements for Active Vibration Control  

NASA Technical Reports Server (NTRS)

This paper presents a method for predicting the power consumption of piezoelectric actuators utilized for active vibration control. Analytical developments and experimental tests show that the maximum power required to control a structure using surface-bonded piezoelectric actuators is independent of the dynamics between the piezoelectric actuator and the host structure. The results demonstrate that for a perfectly-controlled system, the power consumption is a function of the quantity and type of piezoelectric actuators and the voltage and frequency of the control law output signal. Furthermore, as control effectiveness decreases, the power consumption of the piezoelectric actuators decreases. In addition, experimental results revealed a non-linear behavior in the material properties of piezoelectric actuators. The material non- linearity displayed a significant increase in capacitance with an increase in excitation voltage. Tests show that if the non-linearity of the capacitance was accounted for, a conservative estimate of the power can easily be determined.

Brennan, Matthew C.; McGowan, Anna-Maria Rivas

1997-01-01

387

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

388

The investigation of local piezoelectric properties of piezoelectric transducers by acoustic microscopy  

Microsoft Academic Search

Local piezoelectric properties of film and plate piezoelectric transducers have been studied by transmission acoustic microscopy methods at a frequency of 450 MHz with a resolution of 3 ?m. One-dimensional profiles and gray-scale acoustic images of the microstructure have been obtained. It is concluded that acoustic microscopy can be used effectively for the investigation of the nonmechanical characteristics of piezoelectric

R. G. Mayev; O. V. Kolosov; K. A. Atayev; V. M. Levin

1988-01-01

389

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

390

Circular piezoelectric bender laser tuners  

NASA Technical Reports Server (NTRS)

The circular piezoelectric bender laser tuner to replace conventional laser tuners when mirror diameters up to 0.50 inch are sufficient is described. The circular piezoelectric bender laser tuner offers much higher displacements per applied volt and permits laser control circuits to be fabricated using standard operational amplifiers, rather than the expensive high-voltage amplifiers required by conventional tuners. The cost of the device is more than one order of magnitude lower than conventional tuners and the device is very rugged with all mechanical resonances easily designed to be greater than 3kHz. In addition to its use as a laser frequency tuner, the circular bender tuner should find many applications in interferometers and similar devices.

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

1972-01-01

391

Polarization and Characterization of Piezoelectric Polymers  

NASA Technical Reports Server (NTRS)

Piezoelectric materials exhibit an electrical response, such as voltage or charge, in reaction to a mechanical stimuli. The mechanical stimuli can be force, pressure, light, or heat. Therefore, these materials are excellent sensors for various properties. The major disadvantage of state of the art piezoelectric polymers is their lack of utility at elevated temperatures. The objective of this research is to study the feasibility of inducing piezoelectricity in high performance polymer systems. The three aspects of the research include experimental poling, characterization of the capacitance, and demonstration of the use of a piezoelectric polymer as a speaker.

Bodiford, Hollie N.

1995-01-01

392

Significant second-harmonic generation in two lead-free polar oxides BiInO3 and BiAlO3: A first-principles investigation  

NASA Astrophysics Data System (ADS)

Density functional theory with the generalized gradient approximation is applied to study the second-harmonic generation (SHG) in two lead-free polar oxides BiInO3 and BiAlO3. Significant SHG susceptibilities, larger than 500 (10-9 esu), are revealed in both of them. The low frequency limit is found to reach 13 (10-9 esu) and 43 (10-9 esu) for BiInO3 and BiAlO3, respectively. In the meantime, the linear optical response shows weak optical anisotropy and the absorption edge is around 3 eV for both of them. All these results are consistent with their unusual polar structure and demonstrate their potential application in nonlinear optoelectronics.

Ju, Sheng; Cai, Tian-Yi

2009-05-01

393

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

394

Vibration energy harvesting using piezoelectric unimorph cantilevers with unequal piezoelectric and nonpiezoelectric lengths  

PubMed Central

We have examined a piezoelectric unimorph cantilever (PUC) with unequal piezoelectric and nonpiezoelectric lengths for vibration energy harvesting theoretically by extending the analysis of a PUC with equal piezoelectric and nonpiezoelectric lengths. The theoretical approach was validated by experiments. A case study showed that for a fixed vibration frequency, the maximum open-circuit induced voltage which was important for charge storage for later use occurred with a PUC that had a nonpiezoelectric-to-piezoelectric length ratio greater than unity, whereas the maximum power when the PUC was connected to a resistor for immediate power consumption occurred at a unity nonpiezoelectric-to-piezoelectric length ratio.

Gao, Xiaotong; Shih, Wei-Heng; Shih, Wan Y.

2010-01-01

395

Vibration energy harvesting using piezoelectric unimorph cantilevers with unequal piezoelectric and nonpiezoelectric lengths.  

PubMed

We have examined a piezoelectric unimorph cantilever (PUC) with unequal piezoelectric and nonpiezoelectric lengths for vibration energy harvesting theoretically by extending the analysis of a PUC with equal piezoelectric and nonpiezoelectric lengths. The theoretical approach was validated by experiments. A case study showed that for a fixed vibration frequency, the maximum open-circuit induced voltage which was important for charge storage for later use occurred with a PUC that had a nonpiezoelectric-to-piezoelectric length ratio greater than unity, whereas the maximum power when the PUC was connected to a resistor for immediate power consumption occurred at a unity nonpiezoelectric-to-piezoelectric length ratio. PMID:21200444

Gao, Xiaotong; Shih, Wei-Heng; Shih, Wan Y

2010-12-01

396

Vibration energy harvesting using piezoelectric unimorph cantilevers with unequal piezoelectric and nonpiezoelectric lengths  

NASA Astrophysics Data System (ADS)

We have examined a piezoelectric unimorph cantilever (PUC) with unequal piezoelectric and nonpiezoelectric lengths for vibration energy harvesting theoretically by extending the analysis of a PUC with equal piezoelectric and nonpiezoelectric lengths. The theoretical approach was validated by experiments. A case study showed that for a fixed vibration frequency, the maximum open-circuit induced voltage which was important for charge storage for later use occurred with a PUC that had a nonpiezoelectric-to-piezoelectric length ratio greater than unity, whereas the maximum power when the PUC was connected to a resistor for immediate power consumption occurred at a unity nonpiezoelectric-to-piezoelectric length ratio.

Gao, Xiaotong; Shih, Wei-Heng; Shih, Wan Y.

2010-12-01

397

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

398

Lead-Free Bonding Systems.  

National Technical Information Service (NTIS)

Nano-structured interconnect formation and a reworkable bonding process using solder films. Large area fabrication of nano-structured interconnects is demonstrated at a very fine pitch. This technology can be used for pushing the limits of current flip ch...

A. Aggarwal I. R. Abothu P. M. Raj R. R. Tummala

2005-01-01

399

Lead-free electric matches  

Microsoft Academic Search

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

S. F. Son; M. A. Hiskey; D. Naud; J. R. Busse; B. W. Asay

2002-01-01

400

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

401

A self diagnostic system for piezoelectric sensors  

Microsoft Academic Search

A technique for determining the mounting conditions of a piezoelectric accelerometer is presented. This technique electrically stimulates the piezoelectric element in the 'diagnostic' frequency band measuring the electrical frequency response characteristics across a capacitive load impedance. The diagnostic frequency band is tipically much higher than the operating bandwidth of the accelerometer. The resonant frequencies of the accelerometer are included in

William J. Atherton; Patrick M. Flanagan

1989-01-01

402

Harvesting energy from a cantilever piezoelectric beam  

Microsoft Academic Search

Energy harvesting using piezoelectric material is not a new concept, but its small generation capability has not been attractive for mass energy generation. For this reason, little research has been done on the topic. Recently, wearable computer concepts, as well as small portable electrical devices, are a few motivations that have ignited the study of piezoelectric energy harvesting. The theory

Sunghwan Kim; Thomas J. Johnson; William W. Clark

2004-01-01

403

An autonomous piezoelectric shunt damping system  

Microsoft Academic Search

Passive shunt damping involves the connection of an electrical shunt network to a structurally attached piezoelectric transducer. In recent years, a large body of research has focused on the design and implementation of shunt circuits capable of significantly reducing structural vibration. This paper introduces an efficient, light weight, and small-in-size technique for implementing piezoelectric shunt damping circuits. A MOSFET half

Andrew J. Fleming; Sam Behrens; S. O. R. Moheimani

2003-01-01

404

Nonlinear piezoelectric shunting for structural damping  

Microsoft Academic Search

The electromechanical coupling behavior of piezoelectric materials allows their use as damping elements in dynamic structural systems. By shunting the electrical terminals of piezoelectric element bonded to a structure, electrical components can be used to change the apparent dynamic response of the structure. Linear shunting components such as resistive elements or inductive-resistive-capacitive circuits, respectively, have been used to produce behavior

David J. Warkentin; Nesbitt W. Hagood

1997-01-01

405

SH wave propagation in piezoelectric coupled plates  

Microsoft Academic Search

The propagation of shear horizontal (SH) wave in a piezoelectric coupled plate is investigated in this paper. Full account is taken of the piezoelectric coupling effect to the isotropic metal core in the mathematical model. One of the applications of this research is in the damage detection of the host metal structure from the wave propagation signal excited by the

Q. Wang

2002-01-01

406

Modeling of functionally graded piezoelectric ultrasonic transducers  

Microsoft Academic Search

The application of functionally graded material (FGM) concept to piezoelectric transducers allows the design of composite transducers without interfaces, due to the continuous change of property values. Thus, large improvements can be achieved, as reduction of stress concentration, increasing of bonding strength, and bandwidth. This work proposes to design and to model FGM piezoelectric transducers and to compare their performance

Wilfredo Montealegre Rubio; Flvio Buiochi; Julio Cezar Adamowski; Emlio Carlos Nelli Silva

2009-01-01

407

Modeling and Design of Piezoelectric Smart Structures  

Microsoft Academic Search

Modeling and design of piezoelectric smart structures has been studied for enhancing the desire performance. To model such structures, the ability to handle infinite domains and structures with piezoelectric devices is essential. As many factors affect the performance of smart structures, optimization of the parameters is necessary. Infinite\\/semi-infinite domains are modeled by introducing a mathematical boundary within which the finite

Jaehwan Kim

1995-01-01

408

Giant piezoelectricity on Si for hyperactive MEMS.  

PubMed

Microelectromechanical systems (MEMS) incorporating active piezoelectric layers offer integrated actuation, sensing, and transduction. The broad implementation of such active MEMS has long been constrained by the inability to integrate materials with giant piezoelectric response, such as Pb(Mg(1/3)Nb(2/3))O(3)-PbTiO(3) (PMN-PT). We synthesized high-quality PMN-PT epitaxial thin films on vicinal (001) Si wafers with the use of an epitaxial (001) SrTiO(3) template layer with superior piezoelectric coefficients (e(31,f) = -27 3 coulombs per square meter) and figures of merit for piezoelectric energy-harvesting systems. We have incorporated these heterostructures into microcantilevers that are actuated with extremely low drive voltage due to thin-film piezoelectric properties that rival bulk PMN-PT single crystals. These epitaxial heterostructures exhibit very large electromechanical coupling for ultrasound medical imaging, microfluidic control, mechanical sensing, and energy harvesting. PMID:22096193

Baek, S H; Park, J; Kim, D M; Aksyuk, V A; Das, R R; Bu, S D; Felker, D A; Lettieri, J; Vaithyanathan, V; Bharadwaja, S S N; Bassiri-Gharb, N; Chen, Y B; Sun, H P; Folkman, C M; Jang, H W; Kreft, D J; Streiffer, S K; Ramesh, R; Pan, X Q; Trolier-McKinstry, S; Schlom, D G; Rzchowski, M S; Blick, R H; Eom, C B

2011-11-18

409

Data based modeling and control of a dual-stage actuator hard disk drive  

Microsoft Academic Search

A data-based approach is presented for modeling and controller design of a dual-stage servo actuator in a hard disk drive. The servo actuator in this hard disk drive consists of a conventional voice coil motor and a piezo-electrically actuated suspension. A weighted Hankel matrix based real- ization algorithm that uses frequency domain data is applied to estimate a discrete-time model

Uwe Boettcher; Raymond A. de Callafon; Frank E. Talke

2009-01-01

410

SH wave propagation in piezoelectric coupled plates.  

PubMed

The propagation of shear horizontal (SH) wave in a piezoelectric coupled plate is investigated in this paper. Full account is taken of the piezoelectric coupling effect to the isotropic metal core in the mathematical model. One of the applications of this research is in the damage detection of the host metal structure from the wave propagation signal excited by the piezoelectric layer which is surface bonded on the surface of a metal core. This research is distinct from the previous works on SH propagation in piezoelectric structures because the piezoelectric materials were used as the core structure in the previous studies, and the potential of the studies was mainly on time-delay devices. The dispersive characteristics and the mode shapes of the transverse displacement and the electric potential of the piezoelectric layer are theoretically derived. The results from numerical simulations show that the phase velocity of the plate structure tends to the bulk shear wave velocity of the host metal core at high wavenumber when the shear wave velocity of host plate is larger than that of PZT bonded on it. Furthermore, there are three asymptotic solutions of wave propagation when the shear wave velocity of the host plate is smaller than that of PZT. The mode shape of the electric potential of the piezoelectric layer changes from the quadratic shape at lower wavenumber and with thinner piezoelectric layer to the shape with more zero nodes at higher wavenumber and with thicker piezoelectric layer. These findings are significant in the application of wave propagation in piezoelectric coupled structures. PMID:12046935

Wang, Quan

2002-05-01

411

Flutter suppression via piezoelectric actuation  

NASA Technical Reports Server (NTRS)

Experimental flutter results obtained from wind tunnel tests of a two degree of freedom wind tunnel model are presented for the open and closed loop systems. The wind tunnel model is a two degree of freedom system which is actuated by piezoelectric plates configured as bimorphs. The model design was based on finite element structural analyses and flutter analyses. A control law was designed based on a discrete system model; gain feedback of strain measurements was utilized in the control task. The results show a 21 pct. increase in the flutter speed.

Heeg, Jennifer

1991-01-01

412

A piezoelectric cryogenic heat switch.  

PubMed

We have measured the thermal conductance of a mechanical heat switch actuated by a piezoelectric positioner, the PZHS (PieZo electric Heat Switch), at cryogenic temperatures. The thermal conductance of the PZHS was measured between 4 K and 10 K, and on/off conductance ratios of about 100-200 at lowest and highest measures temperature were achieved when the positioner applied its maximum force of 8 N, respectively. We discuss the advantages of using this system in cryogenic applications, and estimate the ultimate performance of an ideal PZHS. PMID:24985863

Jahromi, Amir E; Sullivan, Dan F

2014-06-01

413

Dual-stage track-following servo design for hard disk drives  

Microsoft Academic Search

Discrete time, 25 KTPI track-following servos were designed for magnetic hard disk drive dual stage actuators using the ?-synthesis methodology. The design methodology was tested on two microactuator models. The first is a model of a piezoelectrically actuated suspension, under development by Hutchinson Technology Incorporated. The second is a model of an electrostatically actuated MEMS microactuator, under development by the

Daniel Hernandez; Sung-Su Park; Roberto Horowitz; Andrew K. Packard

1999-01-01

414

Short seeking control with minimum jerk trajectories for dual actuator hard disk drive systems  

Microsoft Academic Search

This paper is concerned with short seeking control for hard disk drives with a dual actuation servo system consisting of a coarse actuator (voice coil motor, VCM) and a fine actuator (piezoelectric actuator, PZT). Short seeking refers to moving the recording head over a few tracks. The primary elements in short seeking control are the feedback controller, the feedforward controller

Jiagen Ding; Federico Marcassa; Masayoshi Tomizuka

2004-01-01

415

Piezoelectric Windmill: A Novel Solution to Remote Sensing  

Microsoft Academic Search

This study demonstrates a technology, ``Piezoelectric Windmill'', for generating the electrical power from wind energy. The electric power-generation from wind energy is based on piezoelectric effect and utilizes the bimorph actuators. Piezoelectric Windmill consists of piezoelectric actuators arranged along the circumference of the mill in the cantilever form. Using the camshaft gear mechanism an oscillating torque is generated through the

Shashank Priya; Chih-Ta Chen; Darren Fye; Jeff Zahnd

2005-01-01

416

Multimode shunt damping of piezoelectric smart panel for noise reduction  

Microsoft Academic Search

Multimode shunt damping of piezoelectric smart panel is studied for noise reduction. Piezoelectric smart panel is a plate structure on which a piezoelectric patch is attached with an electrical shunt circuit. When an incidence sound is impinged on the panel structure, the structure vibrates and the attached piezoelectric patch produces an electrical energy, which can be effectively dissipated as heat

Jaehwan Kim; Joon-Hyoung Kim

2004-01-01

417

An experimental comparison of piezoelectric and constrained layer damping  

Microsoft Academic Search

A qualitative comparison between a piezoelectric vibration absorber and a constrained layer damping treatment is presented. Piezoelectric materials convert mechanical strains into electrical charge. Dissipation of the charge results in attenuation of vibration. The damping is concentrated to a single mode by constructing a piezoelectric absorber. The damped vibration absorber is comprised of the piezoelectric material and a passive electronic

Joseph J. Hollkamp; Robert W. Gordon

1996-01-01

418

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

419

Vibration control efficiency of piezoelectric shunt damping system  

Microsoft Academic Search

The piezoelectric shunt damping technique based on the direct piezoelectric effect has been known as a simple, low-lost, lightweight,\\u000a and easy to implement method for passive damping control of structural vibration. In this technique, a piezoelectric material\\u000a is used to transform mechanical energy to electrical energy. When applying the piezoelectric shunt damping technique to passively\\u000a control structural vibration, the piezoelectric

Dan Wu; Zhichun Yang; Hao Sun

2009-01-01

420

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

421

Characterization of Stress-Strain Response of Lead-Free Solder Joints Using a Digital Image Correlation Technique and Finite-Element Modeling  

NASA Astrophysics Data System (ADS)

The stress-strain response of miniaturized Sn-Ag-Cu (SAC) lead-free solder joints in the thickness range of 80 ?m to about 1.1 mm was studied. A high-resolution three-dimensional (3D) digital image correlation system was used for in situ measurement of displacement and strain fields in the solder joints during tensile testing. These measurements showed that the localization of plastic strain and stress buildup occurs mainly at the interface of the solder. With increasing solder gap thickness the size of the plastically deformed zone in the solder increases, resulting in transformation of a brittle interfacial fracture to a ductile fracture within the bulk of the solder. The experimental deformation plots of solder joints and strain-rate-dependent tensile tests on bulk solder material were used to establish a new constitutive material model for the solder. This strain-rate- and pressure-dependent material model was implemented in ABAQUS through the user subroutine CREEP. In agreement with the experiments, the finite-element method simulation revealed a pronounced thickness effect leading to higher tensile strength of thinner solder joints.

Khatibi, G.; Lederer, M.; Byrne, E.; Kotas, A. Betzwar; Weiss, B.; Ipser, H.

2013-02-01

422

The Effect of Sb Addition on Sn-Based Alloys for High-Temperature Lead-Free Solders: an Investigation of the Ag-Sb-Sn System  

NASA Astrophysics Data System (ADS)

Today there is renewed interest in alloys belonging to the Sb-Sn-X (X = Cu, Ag, Bi) ternary systems and their phase equilibria, phase transformations, and thermodynamic properties because of their possible use as high-temperature lead-free solders in the electronics industry. The integral mixing enthalpy of Ag-Sb-Sn liquid alloys has been measured along five different sections (Ag0.25Sn0.75, Ag0.50Sn0.50, Sb0.30Sn0.70, Sb0.50Sn0.50, and Sb0.70Sn0.30) at 530C, 600C, and 630C, using a high-temperature Calvet calorimeter by dropping pure elements (Ag or Sb) in the binary alloy liquid bath. The ternary extrapolation models of Muggianu and Toop were used to calculate the integral enthalpy of mixing and to compare measured and extrapolated values. Selected ternary alloys have been prepared for thermal investigation by using a differential scanning calorimeter at different heating/cooling rates in order to clarify the temperature of the invariant reactions and the crystallization path.

Li, D.; Delsante, S.; Watson, A.; Borzone, G.

2012-01-01

423

Board-Level Solder Joint Reliability of Edge- and Corner-Bonded Lead-Free Chip Scale Package Assemblies Subjected to Thermal Cycling  

NASA Astrophysics Data System (ADS)

In this paper, we present the results of thermal cycling test for edge- and corner-bonded lead-free chip scale packages (CSPs), which was carried out on the basis of the IPC-9701 test standard. Six materials were used in this study: four edge-bond adhesives and two corner-bond adhesives. These adhesives were compared with CSPs with full capillary flow underfill (FCFU) and without adhesives. The thermal cycling test results show that corner-bond adhesive has comparable solder joint reliability performance with CSP without adhesive, and is better than edge-bond adhesive, followed by CSPs with FCFU. In addition, the adhesives with a low coefficient of thermal expansion, a high glass transition temperature and a intermediate storage modulus yielded good performance. Results of detailed failure analysis indicate that the dominant failure mode is solder bulk fatigue cracking near package and/or printed circuit board (PCB) pads, and that the location of critical solder joints change from die edges to package corners with the introduction of adhesives.

Shi, Hongbin; Tian, Cuihua; Ueda, Toshitsugu

2012-04-01

424

Oxidation kinetics of thin copper films and wetting behaviour of copper and Organic Solderability Preservatives (OSP) with lead-free solder  

NASA Astrophysics Data System (ADS)

The oxide formation on thin copper films deposited on Si wafer was studied by XPS, SEM and Sequential Electrochemical Reduction Analysis SERA. The surfaces were oxidized in air with a reflow oven as used in electronic assembly at temperatures of 100 C, 155 C, 200 C, 230 C and 260 C. The SERA analyses detected only the formation of Cu 2O but the XPS analysis done for the calibration of the SERA equipment proved also the presence of a CuO layer smaller than 2 nm above the Cu 2O oxide. The oxide growth follows a power-law dependence on time within this temperature range and an activation energy of 33.1 kJ/mol was obtained. The wettability of these surfaces was also determined by measuring the contact angle between solder and copper substrate after the soldering process. A correlation between oxide thickness and wetting angle was established. It was found that the wetting is acceptable only when the oxide thickness is smaller than 16 nm. An activation energy of 27 kJ/mol was acquired for the spreading of lead free solder on oxidized copper surfaces. From wetting tests on copper surfaces protected by Organic Solderability Preservatives (OSP), it was possible to calculate the activation energy for the thermal decomposition of these protective layers.

Ramirez, Mauricio; Henneken, Lothar; Virtanen, Sannakaisa

2011-05-01

425

Study on the KLiNbO formation during the production of (K)(1-x)LiNbO lead-free piezoceramics at the morphotropic phase boundary  

NASA Astrophysics Data System (ADS)

Because of the environmental concerns, the manufacture of ceramics based on lead titanate zirconate [Pb(Zr 1- xTi x)O 3-PZT] has been condemned because of the lead toxicity. In this context, the electromechanical properties of sodium, potassium and lithium niobate [(Na 0.5-x/2K 0.5-x/2Li x)NbO 3-NKLN] at the morphotropic phase boundary granted these materials the position of most suitable candidate to replace PZT. However, the production of these ceramics is rather critical mainly because of a natural tendency of forming secondary phases. To help with the studies of the synthesis of this lead-free piezoceramic, this work presents an evaluation of the crystallization of the (Na 0.47K 0.47Li 0.06)NbO 3 phase by solid-state reactions. TG-DTA, XRD, dilatometric and ferroelectric hysteresis analyses indicated that a secondary phase (K 3Li 2Nb 5O 15) crystallizes at temperatures above 850 ?C and also during the sintering of the powders compacts at 1080 ?C. To prevent the formation of this phase, the addition of Na 2Nb 2O 6. nH 2O microfibers obtained through a microwave hydrothermal synthesis was performed in the sintering process. After to this addition, the suppression of the K 3Li 2Nb 5O 15 phase occurred and an increase of the NKLN electrical properties was then obtained.

Paula, Amauri J.; Parra, Rodrigo; Zaghete, Maria A.; Varela, Jos A.

2009-10-01

426

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

427

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

SciTech Connect

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

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

2009-09-15

428

Magneto-optical and Microwave Properties of LuBiIG Thin Films Prepared by Liquid Phase Epitaxy Method from Lead-Free Flux  

NASA Astrophysics Data System (ADS)

Lu2.1 Bi0.9Fe5 O12 (LuBiIG) garnet films are prepared by liquid phase epitaxy (LPE) method on gadolinium gallium garnet (GGG) substrates from lead-free flux. Three-inch single crystal garnet films with (444) orientation and good surface are successfully fabricated. The lattice mismatch to the GGG(111) substrate is as small as 0.08%. The ferromagnetic resonance (FMR) linewidth of the film is 2?H = 2.8-5.1 Oe, the Faraday rotation is 1.64 deg/?m at 633 nm at room temperature and the optical absorption coefficient of the film is 600 cm-1 in visible range and about 100-170 cm-1 when the wavelength is larger than 800 nm. The epitaxy film possesses dominating in-plane magnetization with a saturation magnetization of about 1562G. These superior optical, magnetic-optical (MO) and microwave properties of our garnet films have potential applications in both MO and microwave devices.

Yang, Qing-Hui; Zhnag, Huai-Wu; Wen, Qi-Ye; Liu, Ying-Li; Ihor, Syvorotka M.; Ihor, Syvorotka I.

2009-04-01

429

Photocurrent of lead-free (K0.5Na0.5)(Mn0.005Nb0.995)O3 ferroelectric nanotubes  

NASA Astrophysics Data System (ADS)

We fabricated (K0.5Na0.5)(Mn0.005Nb0.995)O3 (KNMN) nanotubes using (K0.5Na0.5)(Mn0.005 Nb0.995)O3 sol on an anodic aluminum oxide (AAO) template. The highly ordered AAO template was fabricated by a two-step anodization process. Lead-free (K0.5Na0.5)(Mn0.005Nb0.995)O3 ferroelectric nanotubes were fabricated by infiltration with KNMN sol inside the AAO template by a sol-gel process. The outer diameter and thickness of the wall in the KNMN nanotube were about 70 nm and 5 nm, respectively. The crystalline structure, surface morphology, and ferroelectric and photocurrent properties were investigated. The maximum power conversion efficiencies (?) of KNMN nanotubes were higher than that of KNMN film due to the greater effective area (KNMN nanotubes: ? = 0.02%, KNMN film: ? = 0.008%).

Park, Jungmin; Won Ahn, Chang; Won Kim, Ill

2012-07-01

430

Fabrication and properties of PZT and PMN-PT piezoelectric fibers and piezoelectric fiber composites  

Microsoft Academic Search

PZT powder is synthesized by solid reaction and PMN-PT is synthesized by columbite method. PZT and PMN-PT piezoelectric fibers are prepared by sol-powder mixture extrusion. 1-3 piezoelectric fiber composites are fabricated by arraying-casting technique. The influence of fiber composition on dielectric properties and piezoelectric properties are studied. The results show that the values of kt and kt\\/kp of 1-3 composite

Jun Liu; Yan-qing Qiu; Xiang-ling Xu; Cai-feng Chen; Ying Luo

2009-01-01

431

Miniature Piezoelectric Macro-Mass Balance  

NASA Technical Reports Server (NTRS)

Mass balances usually use a strain gauge that requires an impedance measurement and is susceptible to noise and thermal drift. A piezoelectric balance can be used to measure mass directly by monitoring the voltage developed across the piezoelectric balance, which is linear with weight or it can be used in resonance to produce a frequency change proportional to the mass change (see figure). The piezoelectric actuator/balance is swept in frequency through its fundamental resonance. If a small mass is added to the balance, the resonance frequency shifts down in proportion to the mass. By monitoring the frequency shift, the mass can be determined. This design allows for two independent measurements of mass. Additionally, more than one sample can be verified because this invention allows for each sample to be transported away from the measuring device upon completion of the measurement, if required. A piezoelectric actuator, or many piezoelectric actuators, was placed between the collection plate of the sampling system and the support structure. As the sample mass is added to the plate, the piezoelectrics are stressed, causing them to produce a voltage that is proportional to the mass and acceleration. In addition, a change in mass delta m produces a change in the resonance frequency with delta f proportional to delta m. In a microgravity environment, the spacecraft could be accelerated to produce a force on the piezoelectric actuator that would produce a voltage proportional to the mass and acceleration. Alternatively, the acceleration could be used to force the mass on the plate, and the inertial effects of the mass on the plate would produce a shift in the resonance frequency with the change in frequency related to the mass change. Three prototypes of the mass balance mechanism were developed. These macro-mass balances each consist of a solid base and an APA 60 Cedrat flextensional piezoelectric actuator supporting a measuring plate. A similar structure with 3 APA 120 Cedrat flextensional piezoelectric actuators spaced equidistantly at 120 degrees supporting the plate and a softer macro balance with an APA 150 actuator/sensor were developed. These flextensional actuators were chosen because they increase the sensitivity of the actuator to stress, allow the piezoelectric to be pre-stressed, and the piezoelectric element is a stacked multilayer actuator, which has a considerably lower input impedance than a monolithic element that allows for common instruments (e.g., input impedance of 10 megohms) to measure the voltage without rapidly discharging the charge/voltage on the piezoelectric actuator.

Sherrit, Stewart; Trebi-Ollennu, Ashitey; Bonitz, Robert G.; Bar-Cohen, Yoseph

2010-01-01

432

Piezoelectric hydraulic pump with innovative active valves  

NASA Astrophysics Data System (ADS)

The development of a piezoelectric hydraulic pump with innovative active valves is presented in this study. The pump structure basically consists of a diaphragm type piezoelectric stack actuator and two specially designed unimorph disc valves acting as inlet and delivery valves. Static and dynamic piezoelectric finite element analyses were used to maximize the delivered fluid volume per stroke and to predict the resonance characteristics of the pump, respectively. A structural optimization technique was performed to optimize the efficiency of the pump versus its geometrical dimensions. A transient CFD model was used to predict flow rates. Dynamic experiments were also conducted and results are in good agreement with those obtained from the simulation.

Lee, Donggun; Or, Siu W.; O'Neill, Conal H.; Carman, Gregory P.

2002-07-01

433

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

434

High power single crystal piezoelectric transformer  

US Patent & Trademark Office Database

A piezoelectric transformer includes a single crystal relaxor ferroelectric element poled along a [0 11] direction and selected from the group consisting of PZN-PT, PMN-PZT, PZN-PT and PMN-PT. The element has two opposed surfaces substantially perpendicular to the [0 11] direction with an input electrode and an output electrode positioned on one surface. The output electrode is isolated from electrical communication with the input electrode. A ground electrode is positioned on the second, opposed surface. Input electrical energy results in piezoelectric change in the element that is mechanically coupled through the element to generate piezoelectric output energy.

2013-03-12

435

Hard Rock Penetration Technology.  

National Technical Information Service (NTIS)

This session at the Geothermal Energy Program Review X: Geothermal Energy and the Utility Market consisted of five presentations: 'Hard Rock Penetration - Summary' by George P. Tennyson, Jr.; 'Overview - Hard Rock Penetration' by James C. Dunn; 'An Overvi...

2005-01-01

436

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

437

Wear of hard materials by hard particles  

SciTech Connect

Hard materials, such as WC-Co, boron carbide, titanium diboride and composite carbide made up of Mo2C and WC, have been tested in abrasion and erosion conditions. These hard materials showed negligible wear in abrasion against SiC particles and erosion using Al2O3 particles. The WC-Co materials have the highest wear rate of these hard materials and a very different material removal mechanism. Wear mechanisms for these materials were different for each material with the overall wear rate controlled by binder composition and content and material grain size.

Hawk, Jeffrey A.

2003-10-01

438

Hardness of Covalent Crystals  

Microsoft Academic Search

Based on the idea that the hardness of covalent crystal is intrinsic and equivalent to the sum of the resistance to the indenter of each bond per unit area, a semiempirical method for the evaluation of hardness of multicomponent crystals is presented. Applied to beta-BC2N crystal, the predicted value of hardness is in good agreement with the experimental value. It

Faming Gao; Julong He; Erdong Wu; Shimin Liu; Dongli Yu; Dongchun Li; Siyuan Zhang; Yongjun Tian

2003-01-01

439

Linear inertial piezoelectric motor with bimorph disc  

NASA Astrophysics Data System (ADS)

Investigation of a novel design tiny piezoelectric inertial motor is given in the paper. Operation principle of the motor is based on inertial motion of the slider applying sticks and slip phases between stator and slider. Piezoelectric motor has simple design and consists of the slider with a bimorph piezoceramic disc and the clamped cylindrical shaft used for sliding. The advantage of the motor design is the self-moving slider that obtains bidirectional inertial motion when the saw tooth or the pulse type excitation signal is applied at resonant frequency. Numerical investigation of the piezoelectric motor based on finite elements method was performed to analyse natural frequencies, modal shapes of the motor and slider response to the different excitation regimes. The influence of the Coulomb friction on the velocity of the slider is analysed. A prototype inertial piezoelectric motor was built, and measurements of electrical and mechanical characteristics were performed. The results of numerical and experimental study are discussed.

Mazeika, Dalius; Vasiljev, Piotr

2013-03-01

440

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

441

Design Consideration for Nonlead Piezoelectric Transformers.  

National Technical Information Service (NTIS)

The aim of this paper is to find a suitable transformer design for nonlead materials. Leadbased piezoelectric materials have high density, electromechanical coefficients and dielectric constants as compared to that of nonlead materials. Hence, if similar ...

S. Priya H. Kim K. Uchino

2003-01-01

442

Polarization Stability of Amorphous Piezoelectric Polyimides  

NASA Technical Reports Server (NTRS)

Amorphous polyimides containing polar functional groups have been synthesized and investigated for potential use as high temperature piezoelectric sensors. The thermal stability of the piezoelectric effect of one polyimide was evaluated as a function of various curing and poling conditions under dynamic and static thermal stimuli. First, the polymer samples were thermally cycled under strain by systematically increasing the maximum temperature from 50 C to 200 C while the piezoelectric strain coefficient was being measured. Second, the samples were isothermally aged at an elevated temperature in air, and the isothermal decay of the remanent polarization was measured at room temperature as a function of time. Both conventional and corona poling methods were evaluated. This material exhibited good thermal stability of the piezoelectric properties up to 100 C.

Park, C.; Ounaies, Z.; Su, J.; Smith, J. G., Jr.; Harrison, J. S.

2000-01-01

443

Numerical homogenization techniques applied to piezoelectric composites.  

PubMed

With the recent availability of piezoelectric fibers, the design and the analysis of piezoelectric composites needs new modeling tools. Therefore, a numerical homogenization technique has been developed, based on the ATILA finite element code, that combines two techniques: one relying upon the representative volume element (RVE) the other relying upon the wave propagation (WP). The combination of the two methods allows the whole tensor of the homogenized properties of the piezoelectric composite to be found. Considering a fiber embedded in epoxy, the numerical results are compared to the results obtained using previous analytical models, thus validating the models. Even if the method is presented in a particular case, its extension to any piezoelectric composite is straightforward. PMID:12597177

Lenglet, Eve; Hladky-Hennion, Anne-Christine; Debus, Jean-Claude

2003-02-01

444

Pyroelectricity and Piezoelectricity in Nylon 11.  

National Technical Information Service (NTIS)

Pyroelectric and piezoelectric properties of poly(vinylidene fluoride) have been widely reported in the literature. Investigations on similar properties in other classes of polymers have been relatively restricted. This paper describes preliminary pyroele...

M. H. Litt C. Hsu P. Basu

1976-01-01

445

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

446

Development of piezoelectric actuator gas injection valve for JT-60U.  

National Technical Information Service (NTIS)

Piezoelectric actuator gas injection valve by lever for JT-60U have been developed using piezoelectric actuator (Laminated piezoelectric elements). Specifications of the valve are summarized as follows: (1) The piezoelectric actuator gas injection valve b...

H. Hiratsuka Y. Miyo T. Koike M. Shimizu K. Komuro

1995-01-01

447

Study of Intermetallic Growth and Kinetics in Fine-Pitch Lead-Free Solder Bumps for Next-Generation Flip-Chip Assemblies  

NASA Astrophysics Data System (ADS)

With continued advances in microelectronics, it is anticipated that next-generation microelectronic assemblies will require a reduction of the flip-chip solder bump pitch to 100 ?m or less from the current industrial practice of 130 ?m to 150 ?m. With this reduction in pitch size, and thus in bump height and diameter, the interaction between die pad metallurgy and substrate pad metallurgy becomes more critical due to the shorter diffusion path and greater stress. Existing literature has not addressed such metallurgical interaction in actual fine-pitch flip-chip assemblies. This work studies intermetallic growth and kinetics in fine-pitch lead-free solder bumps through thermal aging of flip-chip assemblies. Based on this study, it is seen that Ni from the die pad diffuses to the substrate pad region and Cu from the substrate pad diffuses to the die pad region, thus the resulting intermetallic compounds at the die and substrate pad regions are influenced by the other pad as well. Such cross-pad interaction is much stronger in fine-pitch solder bumps with smaller standoff height. It is seen that the die pad region contains Ni3P and (Cu,Ni)6Sn5 after thermal aging, while the substrate pad region contains Cu3Sn and (Cu,Ni)6Sn5. By digitally measuring the thickness of the interfacial phases, the kinetics parameters and the activation energy were calculated for the growth of (Cu,Ni)6Sn5 on the substrate side. The Cu diffusion coefficient through the intermetallic compound (IMC) layer was found to be 0.03370 ?m2/h, 0.1423 ?m2/h, and 0.4463 ?m2/h at 100C, 125C, and 150C, respectively, and the apparent activation energy for the growth of compound layers was 67.89 kJ/mol.

Tian, Ye; Chow, Justin; Liu, Xi; Wu, Yi Ping; Sitaraman, Suresh K.

2013-02-01

448

Half-Heusler Semiconductors as Piezoelectrics  

NASA Astrophysics Data System (ADS)

We use a first-principles rational-design approach to demonstrate the potential of semiconducting half-Heusler compounds as a previously unrecognized class of piezoelectric materials. We perform a high-throughput scan of a large number of compounds, testing for insulating character and calculating structural, dielectric, and piezoelectric properties. Our results provide guidance for the experimental realization and characterization of high-performance materials in this class that may be suitable for practical applications.

Roy, Anindya; Bennett, Joseph W.; Rabe, Karin M.; Vanderbilt, David

2012-07-01

449

Half-Heusler semiconductors as piezoelectrics.  

PubMed

We use a first-principles rational-design approach to demonstrate the potential of semiconducting half-Heusler compounds as a previously unrecognized class of piezoelectric materials. We perform a high-throughput scan of a large number of compounds, testing for insulating character and calculating structural, dielectric, and piezoelectric properties. Our results provide guidance for the experimental realization and characterization of high-performance materials in this class that may be suitable for practical applications. PMID:22861897

Roy, Anindya; Bennett, Joseph W; Rabe, Karin M; Vanderbilt, David

2012-07-20

450

In situ health monitoring of piezoelectric sensors  

NASA Technical Reports Server (NTRS)

An in situ health monitoring apparatus may include an exciter circuit that applies a pulse to a piezoelectric transducer and a data processing system that determines the piezoelectric transducer's dynamic response to the first pulse. The dynamic response can be used to evaluate the operating range, health, and as-mounted resonance frequency of the transducer, as well as the strength of a coupling between the transducer and a structure and the health of the structure.

Jensen, Scott L. (Inventor); Drouant, George J. (Inventor)

2013-01-01

451

Powering neon lamps through piezoelectric transformers  

Microsoft Academic Search

An investigation of the piezoelectric high-voltage ratio transformer as a potential component for powering neon lamps is discussed. The attractiveness of the piezoelectric technology is primarily the extreme simplicity of the resulting components, which are easy to reproduce in mass production, compared to the widely-used wire-wound ferrite transformers. Furthermore, on account of the electric network behaviour of a piezotransformer, the

P. J. M. Smidt; J. L. Duarte

1996-01-01

452

PIEZOELECTRIC MICRO POWER GENERATOR FOR ENERGY HARVESTING  

Microsoft Academic Search

A thin film lead zirconate titanate Pb(Zr,Ti)O3 (PZT), power generating device is developed. It is designed to resonate at specific vibrational frequencies from an ambient, vibrational energy source, thereby creating electrical energy via the piezoelectric effect. The energy harvesting device uses the piezoelectric d33 mode and is fabricated with three mask steps. Our cantilever device was designed to have a

R. Sood; Y. B. Jeon; S. G. Kim

453

LATERAL LAMINATION APPROACH FOR MULTILAYER PIEZOELECTRIC MICROACTUATOR  

Microsoft Academic Search

This paper reports a simple lateral lamination scheme for the fabrication of multilayer piezoelectric actuators. The fabrication scheme consists of dicing of a high-d 33 piezoelectric coefficient lead zirconate titanate (PZT) material, photolithographic high- aspect-ratio SU-8 definition of electrical isolation, and micromolding of conductive polymer electrodes. Backside and inclined UV exposure has been exploited to secure the 1mm-thick SU-8 pillar

Xiaosong Wu; Guang Yuan; Seong-O Choi; Yanzhu Zhao; Seong-Hyok Kim; Yong-Kyu Yoon; Mark G. Allen

454

Improved Multiple-DOF SAW Piezoelectric Motors  

NASA Technical Reports Server (NTRS)

Surface-acoustic-wave (SAW) piezoelectric motors of a proposed type would be capable of operating in multiple degrees of freedom (DOFs) simultaneously and would be amenable to integration into diverse structures and mechanisms. These motors would be compact and structurally simple and would not contain bearings or lead screws. One example of a particularly useful motor of this type would be a two-dimensional- translation stage. Another such example would be a self-actuated spherical joint that could be made to undergo controlled, simultaneous rotations about two orthogonal axes: Such a motor could serve as a mechanism for aiming an "eyeball" camera or as a compact transducer in, and an integral part of, a joint in a robot arm. The multiple-DOF SAW piezoelectric motors as now proposed would be successors to the ones reported in "Multiple-DOF Surface-Acoustic-Wave Piezoelectric Motors" (NPO-20735), NASA Tech Briefs, Vol. 24, No. 12 (December 2000), page 5b. The basic principle of operation of a multiple-DOF SAW piezoelectric motor is a straightforward extension of that of single-DOF SAW piezoelectric motors, which have been reported in several previous NASA Tech Briefs articles: For example, in the case of a linear SAW piezoelectric motor, piezoelectric transducers at opposite ends of a stator excite surface acoustic waves that travel along the surface of the stator. An object (denoted the slider) is pressed against the stator with sufficient pressure (in practice .300 MPa) that it remains in frictional contact with the stator at all times. The slider rides the crests of the waves and is thereby made to move along the surface of the stator. The direction of motion (forward or backward) is controlled by selecting the relative phase of waves generated by the two piezoelectric transducers. The speed increases with the amplitude of the waves and thus with the magnitude of the voltage applied to the transducers.

Bar-Cohen, Yoseph; Bao, Xiaoqi; Hull, Anthony; Wright, John

2003-01-01

455

Design and Fabrication of Piezoelectric Acoustic Sensor  

Microsoft Academic Search

2 Abstract: - This paper describes a fully integrated acoustic sensor that combines high sensitivity, wide frequency range and low cost of batch processed miniaturized silicon components. A sputtered piezoelectric ZnO layer transforms the mechanical deflection of a thin-etched-Si diaphragm into a piezoelectric charge. ZnO has transparent and conductive properties, which makes it attractive for a variety of scientific and

SHERIF SALEH; HAMED ELSIMARY; AMAL ZAKI; SHAMIM AHMAD

2006-01-01

456

Structural health monitoring using piezoelectric impedance measurements  

Microsoft Academic Search

This paper presents an overview and recent advances in impedance-based structural health monitoring. The basic principle behind this technique is to apply high-frequency structural excitations (typically greater than 30kHz) through surface-bonded piezoelectric transducers, and measure the impedance of structures by monitoring the current and voltage applied to the piezoelectric transducers. Changes in impedance indicate changes in the structure, which in

Daniel J. Inman

2007-01-01

457

Handbook of hard coatings  

SciTech Connect

This book discusses the hard coatings classified as tribologically hard, which are wear resistant and low friction. Three sections discuss tribological properties and new developments. With the development of modern technology in the areas of optical, optoelectronic, and defense related applications, the traditional term hard coatings can be extended. Thus, a system which operates satisfactorily, in a given environment can be said to be hard with respect to that environment. Many hard coatings are ceramic compounds such as oxides, carbides, nitrides, ceramic alloys, cements, diamonds and cubic nitride.

Bunshah, R.; Weissmantel, C. [eds.

2000-07-01

458

Half-Heusler semiconductors as piezoelectrics  

NASA Astrophysics Data System (ADS)

We use a first-principles rational-design approach to demonstrate the potential of semiconducting half-Heusler compounds as a previously-unrecognized class of piezoelectric materials. We scan a large number of compounds, testing for insulating character and calculating structural, dielectric, and piezoelectric properties. Of the 792 compounds considered, 234 are found to be nonmetal