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1

Lead-free multilayer piezoelectric transformer  

NASA Astrophysics Data System (ADS)

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

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

2007-01-01

2

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

E-print Network

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

Rohrer, Gregory S.

3

Current Developments and Prospective of Lead-Free Piezoelectric Ceramics  

Microsoft Academic Search

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

Tadashi Takenaka; Hajime Nagata; Yuji Hiruma

2008-01-01

4

Current status and prospects of lead-free piezoelectric ceramics  

Microsoft Academic Search

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

Tadashi Takenaka; Hajime Nagata

2005-01-01

5

Current Developments and Prospective of Lead-Free Piezoelectric Ceramics  

NASA Astrophysics Data System (ADS)

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

Takenaka, Tadashi; Nagata, Hajime; Hiruma, Yuji

2008-05-01

6

KNN-NTK composite lead-free piezoelectric ceramic  

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

7

A lead-free piezoelectric transformer in radial vibration modes  

NASA Astrophysics Data System (ADS)

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

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

2007-03-01

8

First-principles study on novel lead-free piezoelectric materials  

NASA Astrophysics Data System (ADS)

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

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

2011-12-01

9

New method for fabrication of lead-free BaTiO3 piezoelectric ceramics  

Microsoft Academic Search

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

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

2008-01-01

10

Advances in Lead-Free Piezoelectric Materials for Sensors and Actuators  

PubMed Central

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

Aksel, Elena; Jones, Jacob L.

2010-01-01

11

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

NASA Astrophysics Data System (ADS)

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

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

2012-09-01

12

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

PubMed Central

In a flexible nanocomposite-based nanogenerator, in which piezoelectric nanostructures are mixed with polymers, important parameters to increase the output power include using long nanowires with high piezoelectricity and decreasing the dielectric constant of the nanocomposite. Here, we report on piezoelectric power generation from a lead-free LiNbO3 nanowire-based nanocomposite. Through ion exchange of ultra-long Na2Nb2O6-H2O nanowires, we synthesized long (approximately 50?m in length) single-crystalline LiNbO3 nanowires having a high piezoelectric coefficient (d33 approximately 25 pmV-1). By blending LiNbO3 nanowires with poly(dimethylsiloxane) (PDMS) polymer (volume ratio 1:100), we fabricated a flexible nanocomposite nanogenerator having a low dielectric constant (approximately 2.7). The nanogenerator generated stable electric power, even under excessive strain conditions (approximately 105 cycles). The different piezoelectric coefficients of d33 and d31 for LiNbO3 may have resulted in generated voltage and current for the e33 geometry that were 20 and 100 times larger than those for the e31 geometry, respectively. This study suggests the importance of the blending ratio and strain geometry for higher output-power generation in a piezoelectric nanocomposite-based nanogenerator. PACS 77.65.-j; 77.84.-s; 73.21.Hb PMID:24386884

2014-01-01

13

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

PubMed

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

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

2011-12-27

14

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

NASA Astrophysics Data System (ADS)

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

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

2015-03-01

15

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

NASA Astrophysics Data System (ADS)

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

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

2010-01-01

16

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

Microsoft Academic Search

The influence of calcined temperature and sintered technology on the properties of 0.85 (Na0.5Bi0.5) TiO30.144(K0.5Bi0.5)TiO30.006BaTiO3(NBT-KBT-BT) lead-free piezoelectric ceramics was investigated by conventional solid state method, and the relationship between calcined temperature, sintered technology and properties of NBT-KBT-BT lead-free piezoelectric ceramics was obtained. The influence of calcined temperature on the material phase was investigated by X-ray diffraction(XRD), the influence of sintered

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

2011-01-01

17

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

NASA Astrophysics Data System (ADS)

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

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

2015-01-01

18

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

19

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

NASA Astrophysics Data System (ADS)

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

Jeon, Yu Hong

20

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

NASA Astrophysics Data System (ADS)

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

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

2008-09-01

21

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

PubMed Central

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

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

2014-01-01

22

Bi4Ti3O12-based lead-free piezoelectric ceramics with grain orientation  

Microsoft Academic Search

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

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

2002-01-01

23

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

PubMed

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

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

2014-08-14

24

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

SciTech Connect

The electric-field-induced strain response mechanism in a polycrystalline ceramic/ceramic composite of relaxor and ferroelectric materials has been studied using in situ high-energy x-ray diffraction. The addition of ferroelectric phase material in the relaxor matrix has produced a system where a small volume fraction behaves independently of the bulk under an applied electric field. Inter- and intra-grain models of the strain mechanism in the composite material consistent with the diffraction data have been proposed. The results show that such ceramic/ceramic composite microstructure has the potential for tailoring properties of future piezoelectric materials over a wider range than is possible in uniform compositions.

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

2014-03-28

25

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

26

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

PubMed

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

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

2014-01-01

27

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

NASA Astrophysics Data System (ADS)

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

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

2008-04-01

28

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

29

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

Microsoft Academic Search

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

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

2006-01-01

30

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

E-print Network

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

Cao, Wenwu

31

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

NASA Astrophysics Data System (ADS)

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

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

2014-09-01

32

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

E-print Network

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

Cao, Wenwu

33

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

SciTech Connect

The polymorphic structure evolution of (Ba,Ca)(Zr,Ti)O{sub 3} piezoelectric ceramics was investigated by analysis of the in situ X-ray diffraction and dielectric spectra. The results indicated that a confined orthorhombic (O) phase region induced by the approach of the rhombohedral (R) and tetragonal (T) phases existed in an extremely narrow temperature range of (Ba{sub 0.85}Ca{sub 0.15})(Zr{sub 0.1}Ti{sub 0.9})O{sub 3} composition. The electric properties near the OT phase boundaries of (Ba{sub 0.95}Ca{sub 0.05})(Zr{sub 0.05}Ti{sub 0.95})O{sub 3} and (Ba{sub 0.85}Ca{sub 0.15})(Zr{sub 0.1}Ti{sub 0.9})O{sub 3} were compared. The results suggested that the confined O phase region is an important factor that contributes to the extremely large piezoelectric response.

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

2014-03-17

34

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

PubMed

A high-performance flexible piezoelectric hybrid nanogenerator (HNG) based on lead-free perovskite zinc stannate (ZnSnO3) nanocubes and polydimethylsiloxane (PDMS) composite with multiwall carbon nanotubes (MWCNTs) as supplement filling material is demonstrated. Even without any electrical poling treatment, the HNG possesses an open-circuit voltage of 40 V and a short-circuit current of 0.4 ?A, respectively, under repeated human finger impact. It has been demonstrated that the output volume power density of 10.8 ?W cm(-3) from a HNG can drive several colour light emitting diodes (LEDs) and a charge capacitor that powers up a calculator, indicating an effective means of energy harvesting power source with high energy conversion efficiency (?1.17%) for portable electronic devices. PMID:25827201

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

2015-04-24

35

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

PubMed

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

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

2015-03-11

36

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

37

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

SciTech Connect

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

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

2014-07-28

38

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

NASA Astrophysics Data System (ADS)

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

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

2014-07-01

39

Determination of crystallographic orientation of lead-free piezoelectric (K,Na)NbO{sub 3} epitaxial thin films grown on SrTiO{sub 3} (100) surfaces  

SciTech Connect

Crystallographic structure of sol-gel-processed lead-free (K,Na)NbO{sub 3} (KNN) epitaxial films on [100]-cut SrTiO{sub 3} single-crystalline substrates was investigated for a deeper understanding of its piezoelectric response. Lattice parameter measurement by high-resolution X-ray diffraction and transmission electron microscopy revealed that the orthorhombic KNN films on SrTiO{sub 3} (100) surfaces are [010] oriented (b-axis-oriented) rather than commonly identified c-axis orientation. Based on the crystallographic orientation and corresponding ferroelectric domain structure investigated by piezoresponse force microscopy, the superior piezoelectric property along b-axis of epitaxial KNN films than other orientations can be explained.

Yu, Qi; Zhu, Fang-Yuan; Cheng, Li-Qian; Wang, Ke; Li, Jing-Feng, E-mail: jingfeng@mail.tsinghua.edu.cn [State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, 100084 Beijing (China)] [State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, 100084 Beijing (China)

2014-03-10

40

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

SciTech Connect

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

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

2009-06-01

41

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

NASA Astrophysics Data System (ADS)

Lead-free piezoelectric ceramics (1- x) [(0.97Bi0.5Na0.5TiO3)]-0.03BaZrO3- xLiNbO3 (BNT-BZ3- xLN) with x = (0-0.07) were synthesized using the conventional solid-state reaction method, and their crystal structure, microstructure, and dielectric, ferroelectric and piezoelectric properties were investigated as a function of the LN content. The X-ray diffraction patterns revealed the formation of a single-phase perovskite structure for all the LN-modified BNT-BZ ceramics in this study. The results indicate that the LN substitution into BNT-BZ3 induces a transition from a ferroelectric to a diffuse and/or relaxor state accompanying a field-induced strain of 0.20% for x = 0.05 at an applied field of 6 kV/mm. The corresponding dynamic piezoelectric coefficient for this composition was ( S max/ E max = 333 pm/V). A significant reduction of the coercive field ( E c) and enhancement of the piezoelectric constant ( d 33) from 98 pC/N for x = 0 to 117 pC/N x = 0.01 was observed.

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

2015-02-01

42

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

E-print Network

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

Cao, Wenwu

43

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

NASA Astrophysics Data System (ADS)

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

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

2015-02-01

44

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

45

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

NASA Astrophysics Data System (ADS)

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

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

2015-03-01

46

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

NASA Astrophysics Data System (ADS)

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

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

2010-09-01

47

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

SciTech Connect

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

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

2010-06-15

48

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

Microsoft Academic Search

A new U-type micro-actuator for precisely positioning a magnetic head in high-density hard disk drives was proposed and developed. The micro-actuator is composed of a U-type stainless steel substrate and two piezoelectric ceramic elements. Using a high-d31 piezoelectric coefficient PMN-PZT ceramic plate and adopting reactive ion etching process fabricate the piezoelectric elements. Reliability against temperature was investigated to ensure the

Yang Jing; Jianbin Luo; Wenyan Yang; Guoxian Ju

2004-01-01

49

Lead-free piezoceramics  

Microsoft Academic Search

Lead has recently been expelled from many commercial applications and materials (for example, from solder, glass and pottery glaze) owing to concerns regarding its toxicity. Lead zirconium titanate (PZT) ceramics are high-performance piezoelectric materials, which are widely used in sensors, actuators and other electronic devices; they contain more than 60 weight per cent lead. Although there has been a concerted

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

2004-01-01

50

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

NASA Astrophysics Data System (ADS)

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

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

2015-02-01

51

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

SciTech Connect

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

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

2014-03-21

52

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

SciTech Connect

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

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

2013-07-14

53

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

NASA Astrophysics Data System (ADS)

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

Li, Fei; Jin, Li; Guo, Runping

2014-12-01

54

A study of microstructural development, hardness and micro-creep of Sn-3.5Ag-0.7Cu lead-free solder alloy prepared by rapid solidification  

NASA Astrophysics Data System (ADS)

The Sn-3.5Ag-0.7Cu lead-free solder alloy has been prepared by normal casting and melt-spinning techniques to investigate the microstructural development, hardness and micro-creep of this alloy due to rapid solidification. The microstructure of the rapidly solidified ribbons and ingot samples has been investigated by SEM and X-ray diffraction (XRD) techniques. The results showed that the structure of the alloy prepared by normal casting is composed of Cu-Sn and Ag-Sn IMCs finely dispersed in Sn matrix, while these fine dispersions are not present in the rapidly solidified sample indicating that the rapid solidification rate is high enough to retain most of the Ag and Cu elements in nonequilibrium supersaturated solid solutions of ?-Sn. Additionally, the mechanical properties of both slowly and rapidly cooled samples are examined by using Vickers microhardness tester at different loads in the range of them 0.098 to 4.9 N. The hardness value of the rapidly cooled sample was found to be 1.3 times higher than that of the slowly cooled sample due to refinement of the rapidly cooled sample as well as the nonequilibrium solid solutions of Ag and Cu in the ?-Sn matrix. Besides, indentation creep behavior of both slowly and rapidly cooled samples is examined by using Vickers microhardness tester for three different values of the applied loads.

Gouda, El Said

2011-09-01

55

Lead-free primary explosives  

DOEpatents

Lead-free primary explosives of the formula (cat)Y[MII(T)X(H2O)6-X]Z, where T is 5-nitrotetrazolate, and syntheses thereof are described. Substantially stoichiometric equivalents of the reactants lead to high yields of pure compositions thereby avoiding dangerous purification steps.

Huynh, My Hang

2010-06-22

56

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

PubMed

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

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

2015-03-18

57

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

SciTech Connect

A structural coexistence of rhombohedral (R) and tetragonal (T) phases has been revealed in the (001){sub c}-cut lead-free 0.93(Bi{sub 1/2}Na{sub 1/2})TiO{sub 3}0.07BaTiO{sub 3} (BNB7T) piezoelectric crystals, which grown by the self-flux method, in the lower temperatures by high-resolution synchrotron X-ray diffraction, reciprocal space mapping, and transmission electron microscopy. The dielectric permittivity exhibits a thermal hysteresis in the region of 120260?C, implying a first-order-like phase transition from R+T to T. The real part (??) of dielectric permittivity begins to deviates from the Curie-Weiss equation, ???=?C/(T ? T{sub o}), from the Burns temperature T{sub B}?=?460?C, below which the polar nanoregions (or nanoclusters) develop and attenuate dielectric responses. The polar nanoregions of 510?nm were revealed by high-resolution transmission electron microscope. The normal piezoelectric coefficient d{sub 33} exhibits a rapid increase at E?=?1520?kV/cm and reaches a maximum of d{sub 33} ?450 pC/N. The high piezoelectric response and E-field induced strain in BNB7T single crystals can be attributed to structural phase transitions under an E-field application.

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

2014-01-07

58

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

59

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

60

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

PubMed Central

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

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

2013-01-01

61

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

NASA Astrophysics Data System (ADS)

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

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

2011-02-01

62

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

SciTech Connect

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

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

2010-05-15

63

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

64

Lead-free transducer for non-destructive evaluation  

NASA Astrophysics Data System (ADS)

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

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

2007-07-01

65

Interface failure in lead free solder joints  

Microsoft Academic Search

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

Robert Darveaux; Corey Reichman; Nokibul Islam

2006-01-01

66

Accelerated Aging of Lead-Free Propellant  

NASA Technical Reports Server (NTRS)

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

Furrow, Keith W.; Jervey, David D.

2000-01-01

67

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

NASA Astrophysics Data System (ADS)

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

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

2014-12-01

68

Shear deformation of lead free solder joints  

Microsoft Academic Search

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

Robert Darveaux

2005-01-01

69

Lead-Free Surface Finishes for Electronic Components  

E-print Network

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

70

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

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

71

Mechanical bend fatigue reliability of lead-free PBGA assemblies  

Microsoft Academic Search

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

Krishna Jonnalagadda; M. Patel; Andrew Skipor

2002-01-01

72

Local and Global Properties of a Lead-Free Solder  

NASA Astrophysics Data System (ADS)

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

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

2013-07-01

73

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

74

The current status of lead-free solder alloys  

Microsoft Academic Search

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

D. Suraski; K. Seelig

2001-01-01

75

NASA-DoD Lead-Free Electronics Project  

NASA Technical Reports Server (NTRS)

The primary technical objective of the project is to undertake comprehensive testing to generate information on failure modes/criteria to better understand the reliability of: Packages (e.g., TSOP, BGA, PDIP) assembled and reworked with lead-free alloys Packages (e.g., TSOP, BGA, PDIP) assembled and reworked with mixed (lead/lead-free) alloys.

Kessel, Kurt

2007-01-01

76

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

Microsoft Academic Search

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

Ning-Cheng Lee; M. Bixenman

2002-01-01

77

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

Microsoft Academic Search

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

Feng Gao; H. Nishikawa; T. Takemoto

2007-01-01

78

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

79

Novel Testing Instrument for Lead-Free Solder Characterization  

Microsoft Academic Search

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

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

2011-01-01

80

Development of Sn-Zn-Cu lead free solder  

Microsoft Academic Search

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

Yang Min; Liu Xiuzhong; Liu Xinghong; Dai Jiahui

2010-01-01

81

The creep of lead-free solders at elevated temperatures  

Microsoft Academic Search

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

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

2001-01-01

82

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

83

Lead-free BaTiO3 nanowires-based flexible nanocomposite generator.  

PubMed

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

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

2014-08-01

84

Wettability analysis of tin-based, lead free solders  

SciTech Connect

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

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

1992-01-01

85

The creep of lead-free solders at elevated temperatures  

Microsoft Academic Search

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

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

2001-01-01

86

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

PubMed Central

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

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

2013-01-01

87

Nanoscale Mechanical Properties of Intermetallics in Lead-Free Systems  

Microsoft Academic Search

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

M. Braunovic; D. Gagnon; L. Rodrigue

2006-01-01

88

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

SciTech Connect

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

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

2007-12-01

89

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

SciTech Connect

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

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

2014-07-28

90

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

NASA Astrophysics Data System (ADS)

In this work, a large size lead-free piezoelectric single crystal, (K,Na,Li)(Nb,Ta,Sb)O3 (KNLNTS) with the dimensions of 8.58.513.5 mm3 was successfully grown by the top-seeded solution growth method. This KNLNTS single crystal with high compositional homogeneity is in the tetragonal phase at room temperature. The Curie temperature TC of the tetragonal-cubic phase transition temperature is 210 C. The piezoelectric coefficients and electromechanical coupling factors of the [001]C oriented KNLNTS single crystal are d33=172.55 pC/N, d31=-71.90 pC/N, k31=0.327, k33=0.523, and kt=0.541. In addition, the crystal shows good thermal stability so that it can be used for making high temperature electromechanical devices.

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

2015-01-01

91

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

92

Lead-Free Experiment in a Space Environment  

NASA Technical Reports Server (NTRS)

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

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

2012-01-01

93

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

Microsoft Academic Search

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

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

1994-01-01

94

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

E-print Network

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

Krsmanovic, Dalibor

2011-11-08

95

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

E-print Network

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

Volinsky, Alex A.

96

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

NASA Astrophysics Data System (ADS)

Using electron diffraction, trends in the local structural behaviour of the KxNa1-xNbO3 (KNN x) 'solid solution' system are investigated and interpreted using an order/disorder based theoretical framework. At room temperature, electron diffraction shows a single plane of transverse polarised, diffuse intensity perpendicular to [0 1 0]p* (p for parent sub-structure) across the entire phase diagram, indicative of ferroelectric disorder along the [0 1 0]p direction co-existing with long range ferroelectric order along the orthogonal [1 0 0]p and [0 0 1]p directions. An additional characteristic pattern of diffuse scattering is also observed, involving rods of diffuse intensity running along the [1 0 0]p* and [0 0 1]p* directions of the perovskite sub-structure and indicative of octahedral tilt disorder about the [1 0 0]p and [0 0 1]p axes co-existing with long range ordered octahedral tilting around the [0 1 0]p direction. A possible crystal chemical explanation for the existence of this latter octahedral tilt disorder is explored through bond valence sum calculations. The possible influence of both types of disorder on the previously refined, room temperature space group/s and average crystal structure/s is examined.

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

2012-11-01

97

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

SciTech Connect

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

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

2009-07-23

98

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

99

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

100

Investigation of multi-component lead-free solders  

NASA Astrophysics Data System (ADS)

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

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

1994-08-01

101

Rare earths in lead-free oxyfluoride germanate glasses  

NASA Astrophysics Data System (ADS)

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

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

2015-01-01

102

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

NASA Astrophysics Data System (ADS)

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

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

1994-07-01

103

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

104

Development of fluxes for lead-free solders containing zinc  

SciTech Connect

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

Vaynman, S.; Fine, M.E.

1999-11-19

105

High-Temperature Piezoelectrics with Large Piezoelectric Coefficients  

NASA Astrophysics Data System (ADS)

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

Shinekumar, K.; Dutta, Soma

2015-02-01

106

Piezoelectric Polymers  

NASA Technical Reports Server (NTRS)

The purpose of this review is to detail the current theoretical understanding of the origin of piezoelectric and ferroelectric phenomena in polymers; to present the state-of-the-art in piezoelectric polymers and emerging material systems that exhibit promising properties; and to discuss key characterization methods, fundamental modeling approaches, and applications of piezoelectric polymers. Piezoelectric polymers have been known to exist for more than forty years, but in recent years they have gained notoriety as a valuable class of smart materials.

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

2001-01-01

107

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

108

Mechanical Properties and Microstructure Investigation of Lead Free Solder  

NASA Technical Reports Server (NTRS)

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

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

2005-01-01

109

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

NASA Astrophysics Data System (ADS)

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

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

2010-09-01

110

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

NASA Astrophysics Data System (ADS)

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

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

2011-07-01

111

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

Microsoft Academic Search

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

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

2011-01-01

112

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

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

113

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

NASA Astrophysics Data System (ADS)

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

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

2015-01-01

114

Piezoelectric spectroscopy  

Microsoft Academic Search

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

Jie Fang Li; Paul Moses; Dwight Viehland

1994-01-01

115

Piezoelectricity Demo  

NSDL National Science Digital Library

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

116

Piezoelectric films  

NASA Astrophysics Data System (ADS)

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

Shermergor, Timofei Dmitrievich; Strel'Tsova, Natalia Nikolaevna

117

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

NASA Technical Reports Server (NTRS)

This presentation will provide the technical background and specific information published in literature related to reliability test, analyses, modeling, and associated issues for lead-free solder package assemblies in comparison to their tin-lead solder alloys. It also presents current understanding of lead-free thermal cycle test performance in support.

Ghaffarian, Reza

2005-01-01

118

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

E-print Network

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

Bennett, Gisele

119

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

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

120

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

Microsoft Academic Search

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

Ning-Cheng Lee; Mike Bixenman

2002-01-01

121

Manufacturing feasibility of several lead-free solders for electronic assembly  

Microsoft Academic Search

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

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

1994-01-01

122

Reduction of lead free solder aging effects using doped SAC alloys  

Microsoft Academic Search

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

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

2010-01-01

123

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

Microsoft Academic Search

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

Ji Wu; Michael G. Pecht

2006-01-01

124

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

NASA Astrophysics Data System (ADS)

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

Jiang, Hongjin

125

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

Microsoft Academic Search

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

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

2011-01-01

126

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

PubMed

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

Thomas, Vernon George

2013-10-01

127

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

Microsoft Academic Search

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

Tadashi Takenaka; Hajime Nagata

2006-01-01

128

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

PubMed Central

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

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

2014-01-01

129

Intermediate strain rate dependant mechanical properties for lead-free solders  

Microsoft Academic Search

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

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

2010-01-01

130

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

DOEpatents

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

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

1998-01-01

131

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

NASA Astrophysics Data System (ADS)

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

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

2008-04-01

132

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

PubMed

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

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

2015-01-01

133

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

PubMed

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

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

2014-11-01

134

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...

135

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...

136

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

NASA Astrophysics Data System (ADS)

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

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

2014-09-01

137

How to Identify Lead Free Certification Marks for Drinking Water System & Plumbing Products  

EPA Science Inventory

The Reduction of Lead in Drinking Water Act went into effect on January 4, 2014. The Act has reduced the lead content allowed in water system and plumbing products by changing the definition of lead free in Section 1417 of the Safe Drinking Water Act (SDWA) from not more than 8% ...

138

Synthesis of piezoelectric materials by ultrasonic assisted hydrothermal method  

NASA Astrophysics Data System (ADS)

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

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

2012-05-01

139

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

NASA Astrophysics Data System (ADS)

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

Kounga, Alain Brice; Zhang, Shan-Tao; Jo, Wook; Granzow, Torsten; Rdel, Jrgen

2008-06-01

140

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

SciTech Connect

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

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

2011-02-15

141

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

Microsoft Academic Search

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

Naoe Hosoda; Tadatomo Suga

2003-01-01

142

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

Microsoft Academic Search

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

M. GONZALEZ; B. VANDEVELDE; E. BEYNE

143

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

Microsoft Academic Search

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

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

2006-01-01

144

Lead-free solder material characterization for thermo-mechanical modeling  

Microsoft Academic Search

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

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

2008-01-01

145

Development of SnZn lead-free solders bearing alloying elements  

Microsoft Academic Search

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

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

2010-01-01

146

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

Microsoft Academic Search

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

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

2005-01-01

147

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

Microsoft Academic Search

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

T. T. Mattila; J. K. Kivilahti

2006-01-01

148

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

149

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

150

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

E-print Network

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

Sandborn, Peter

151

Piezoelectric properties of lithium modified silver niobate perovskite single crystals  

NASA Astrophysics Data System (ADS)

We report the growth and the piezoelectric properties of lead-free perovskite single crystals of Ag1-xLixNbO3. It possesses a rhombohedral structure with high ferroelectric phase transition (Tc=548K for x =0.086) and large spontaneous polarization (Ps40?C/cm2 for x =0.062) along the ?111?c direction of pseudocubic perovskite structure for x >0.05-0.06. High quasistatic d33210pC/N and low dielectric constant have lead to a very large value of piezoelectric voltage constant g3353.910-3Vm/N for the ?001?c-cut crystal of this simple perovskite. It has been shown that Li substitution might enhance the piezoelectric coefficient of the crystal. The excellent piezo-/ferroelectricity of this system are considered to be facilitated by the strong polarization nature of both Ag and Li in the perovskite structure. Our findings may stimulate further interests in the development of lead-free piezoelectrics.

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

2008-04-01

152

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

Microsoft Academic Search

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

Ikuo Shohji; Colin Gagg; William J. Plumbridge

2004-01-01

153

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

154

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

155

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

156

Theoretical prediction of new high-performance lead-free ferroelectrics  

Microsoft Academic Search

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

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

2005-01-01

157

Piezoelectric Ultrasonic Micromotors  

E-print Network

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

Flynn, Anita M.

1995-06-01

158

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

NASA Astrophysics Data System (ADS)

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

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

2015-03-01

159

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

160

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

161

"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

162

Temperature Dependence of Young's Modulus and Internal Friction in Sn-Zn-Al Lead-Free Solder  

NASA Astrophysics Data System (ADS)

There have hardly been experimental studies of the mechanical properties of Sn-7Zn-0.006Al lead-free solder. The temperature dependence of Young's modulus E and internal friction Q-1 were investigated in Sn-7Zn-0.006Al, Sn-7Zn, and Sn-8Zn-3Bi solders using flexural vibration. Sn-7Zn-0.006Al solder showed the smallest E drop with increasing temperature, representing heat-softenig. Three Q-1 peaks appeared at around 90-100C (1st), 135-140 (2nd), and 175-180C (3rd) in Sn-7Zn-0.006Al and Sn-7Zn, and two Q-1 peaks at around 90C (1st) and 135C (2nd) in Sn-8Zn-3Bi. To investigate the origin of these Q-1 peaks, vibration experiments at lower frequencies were also carried out. From Arrhenius plots for the Q-1 peaks in two vibration experiments, the 3rd Q-1 peak in Sn-7Zn-0.006Al, the 2nd Q-1 peak in Sn-7Zn and those at low frequencies in Sn-8Zn-3Bi were relaxation phenomena obeying the Arrhenius equation, whose activation energies were determined to be 83kJ/mol, 144kJ/mol, and 98kJ/mol, respectively. It was estimated that the origin of these Q-1 peaks was related to the grain boundary from these values, and that Sn-7Zn-0.006Al alloy was refined in microstructure by the addition of a very small amount of Al and superior to other Sn-Zn system solders with regard to mechanical properties.

Fujii, Yasumasa; Ono, Teruaki

163

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

Microsoft Academic Search

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

Dongkai Shangguan; Achyuta Achari; Wells Green

1994-01-01

164

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

Microsoft Academic Search

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

Ravikumar Sanapala; Bhanu Sood; Diganta Das; Michael Pecht

2009-01-01

165

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

NASA Astrophysics Data System (ADS)

Lead free electronics soldering is driven by a combination of health and environmental concerns, international legislation and marketing pressure by lead free electronics manufacturing competitors. Since July 1, 2006, companies that do not comply with the European Union legislation are not able to sell circuit assemblies with lead solder in the European Union. China has developed its own regulations, based on the European Union documents with a compliance date of March 1, 2007. Extensive testing by the electronics community has determined that the Sn - Ag - Cu (SAC) family of alloys is the preferred choice for lead free Surface Mount Technology (SMT) soldering. The 96.5Sn/3.0Ag/0.5Cu alloy was used in this study. Lead free soldering requires an increase in reflow peak temperatures which further aggravates component moisture sensitivity risks and thereby decreases assembly yield. Prior research has revealed an enhanced solder spreading phenomena at lower peak temperature and shorter time above liquidus with 63Sn/37Pb solder. This current research investigated solder wetting reactions in 63Sn/37Pb and 96.5Sn/3.0Ag/0.5Cu (SAC305) using materials and manufacturing systems that are industry relevant. The objective was to advance the knowledge base of metal wetting while developing a reflow assembly process that minimized the component defect rates. The components are damaged during reflow by popcorn delamination, which is the result of moisture absorption and subsequent rapid evaporation. A classical Design Of Experiments (DOE) approach was used, with wetted area as the response variable. Outside of the DOE, substrate dissolution depth, and substrate surface new phase formation (reaction product) distance from the triple line (solder wetting front) and reaction product thickness in the solder joint (under the solder) were also analyzed. The samples were analyzed for correlation of reflow peak temperature, reflow Time Above Liquidus (TAL), wetted area, reaction product distance from the triple line, substrate dissolution depth, triple line ridge (substrate protrusion into the molten solder) formation and reaction product thickness in the solder joint. The general results are (1) an improved understanding of 63Sn/37Pb and 96.5Sn/3.0Ag/0.5Cu WT% solder wetting reactions, (2) reduced 63Sn/37Pb and SAC reflow peak temperatures, and thereby reduced risk of moisture sensitivity damage to components. The significance of these results are (1) enhanced applied understanding of the complexity of molten metal wetting a substrate and (2) enhanced assembly yield due to minimal aggravation of component moisture sensitivity. The uniqueness of this research is that it utilized a holistic Systems Science approach which provided a combined microscopic (substrate and molten metal reactions) and macroscopic (wetted area) analysis of metal wetting using materials and processes that were directly relevant to electronics manufacturing.

Anson, Scott J.

166

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

167

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

PubMed

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

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

2015-01-01

168

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

NASA Astrophysics Data System (ADS)

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

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

2015-02-01

169

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

PubMed Central

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

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

2015-01-01

170

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

NASA Astrophysics Data System (ADS)

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

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

2009-05-01

171

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

NASA Astrophysics Data System (ADS)

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

Kalkundri, Kaustubh Jayant

172

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

173

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

174

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

175

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

NASA Astrophysics Data System (ADS)

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

Nguyen, Van Luong; Kim, Ho-Kyung

2014-09-01

176

SHPB tests for mechanical behavior of lead-free solder alloys  

NASA Astrophysics Data System (ADS)

Dynamic behavior of solder joints in microelectronic packages is key issue for drop/impact reliability design of mobile electronic products. The dynamic mechanical behavior of 63Sn37Pb, 96.5Sn3.5Ag and 96.5Sn3.0Ag0.5Cu at high strain rates have been investigated by using the split Hopkinson pressure/tension bar testing technique (SHPB). Stress-strain relations of the three solders were obtained at strain rates of 600s-1, 1200s-1 and 2200s-1, respectively. The experimental results show that the lead-free solders are strongly strain rate dependent. 96.5Sn3.5Ag is the most sensitive to strain rate, while 63Sn37Pb is the least. 96.5Sn3.0Ag0.5Cu has the greatest yield stress and tensile strength. Relations of the yield stress and the tensile strength of the solders with strain rate were fitted.

Qin, Fei; An, Tong; Chen, Na

2008-11-01

177

A novel high-speed shear test for lead-free flip chip packages  

NASA Astrophysics Data System (ADS)

Despite the importance of lead-free solders in modern environmentally friendly packaging, few studies have been conducted on their mechanical reliability at the wafer level. In the present study, high-speed die shear tests were conducted to investigate the effects of strain rate on the shearing resistance and fracture mode of Sn-3wt%Ag-0.5wt%Cu solder joints on electroless Ni-P/immersion Au surface finish pads. The results indicated that the solder joints underwent ductile and mixed ductile-brittle fracture at low (<855 s-1) and high (>25,385 s-1) strain rates, respectively. Thus, the overall shear stress-strain curve can be divided into three areas according to Hollomon's law, starting from low strain rates: area I, 100% ductile fracture of the solder itself; area II, mixed ductile-brittle fracture resulting in a ductile-brittle transition region; and area III, 100% brittle fracture at the interface between the intermetallic compound and the Ni-P layer.

Huh, Seok-Hwan; Kim, Kang-Dong; Kim, Keun-Soo; Jang, Joong-Soon

2012-02-01

178

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

179

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

PubMed

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

Fujiuchi, Yukiko; Morita, Takeshi

2014-10-01

180

Microstructure Characterization Of Lead-Free Solders Depending On Alloy Composition  

NASA Astrophysics Data System (ADS)

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

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

2010-11-01

181

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

NASA Astrophysics Data System (ADS)

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

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

2001-08-01

182

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

183

Active piezoelectric damping composites  

Microsoft Academic Search

Patches of active piezoelectric damping composites (APDC) consisting of piezoelectric rods, which are obliquely embedded across the thickness of viscoelastic damping matrix, are presented as a viable candidate for smart actuation. In this configuration, activation of the piezo-rods simultaneously enhances both the shear and compression damping characteristics of the smart composite actuator. With such active\\/passive capabilities, the APDC presents an

A. Baz; A. Tempia

2004-01-01

184

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

E-print Network

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

Boyer, Edmond

185

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

SciTech Connect

Purpose: This study was conducted to ensure that various lead shield apron manufacturers provided accurate attenuation factors regardless of whether the apron was made of lead-based or lead-free equivalent material. Methods: A calibrated ionization survey meter was placed at chest height and 36 cm horizontally away from a solid water phantom on a simulator couch. Measurements were done with or without apron. Radiation field was set to 24cmx24cm with the phantom at 100cm source-to-surface distance. Irradiation time was set for 1 minute at voltages of 60, 80, 100 and 120 kVp. Current was set at 6mA. Results: Between 60 kVp and 120 kVp, the transmission through 0.50 mm of lead-based apron was between 1.0% and 6.5% with a mean value of 3.2% and a standard deviation (s.d.) of 1.4%. The transmissions through the 0.50 mm lead-free aprons were 1.0 % to 12.0% with a mean value of 6.1% and s.d. of 2.6%. At 120 kVp, the transmission value was 6.5% for 0.50 mm lead-based apron and 11.1% to 12.0% for 0.50 mm lead-free aprons. The radiation transmissions at 80 kVp, measured in two different 0.5 mm lead-free aprons, were 4.3% each. However, only 1.4% transmission was found through the lead-based apron. Overall, the radiation transmitted through the lead-based apron was 1/3 transmission of lead-free at 80kVp, and half value of lead-free aprons at 100 and 120 kVp. Conclusion: Even though lead-based and lead-free aprons all claimed to have the same lead equivalent thickness, the transmission might not be the same. The precaution was needed to exercise diligence in quality assurance program to assure adequate protection to staff who wear it during diagnostic procedures. The requirement for aprons not only should be in certain thickness to meet state regulation but also to keep reasonably achievable low exposure with the accurate labeling from manufacturers.

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

2014-06-01

186

Intermetallics Characterization of Lead-Free Solder Joints under Isothermal Aging  

NASA Astrophysics Data System (ADS)

Solder interconnect reliability is influenced by environmentally imposed loads, solder material properties, and the intermetallics formed within the solder and the metal surfaces to which the solder is bonded. Several lead-free metallurgies are being used for component terminal plating, board pad plating, and solder materials. These metallurgies react together and form intermetallic compounds (IMCs) that affect the metallurgical bond strength and the reliability of solder joint connections. This study evaluates the composition and extent of intermetallic growth in solder joints of ball grid array components for several printed circuit board pad finishes and solder materials. Intermetallic growth during solid state aging at 100C and 125C up to 1000 h for two solder alloys, Sn-3.5Ag and Sn-3.0Ag-0.5Cu, was investigated. For Sn-3.5Ag solder, the electroless nickel immersion gold (ENIG) pad finish was found to result in the lowest IMC thickness compared to immersion tin (ImSn), immersion silver (ImAg), and organic solderability preservative (OSP). Due to the brittle nature of the IMC, a lower IMC thickness is generally preferred for optimal solder joint reliability. A lower IMC thickness may make ENIG a desirable finish for long-life applications. Activation energies of IMC growth in solid-state aging were found to be 0.54 0.1 eV for ENIG, 0.91 0.12 eV for ImSn, and 1.03 0.1 eV for ImAg. Cu3Sn and Cu6Sn5 IMCs were found between the solder and the copper pad on boards with the ImSn and ImAg pad finishes. Ternary (Cu,Ni)6Sn5 intermetallics were found for the ENIG pad finish on the board side. On the component side, a ternary IMC layer composed of Ni-Cu-Sn was found. Along with intermetallics, microvoids were observed at the interface between the copper pad and solder, which presents some concern if devices are subject to shock and vibration loading.

Choubey, Anupam; Yu, Hao; Osterman, Michael; Pecht, Michael; Yun, Fu; Yonghong, Li; Ming, Xu

2008-08-01

187

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

188

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

NASA Astrophysics Data System (ADS)

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

Mahesh, P.; Pamu, D.

2015-02-01

189

Piezoelectric composite materials  

NASA Technical Reports Server (NTRS)

A laminated structural devices has the ability to change shape, position and resonant frequency without using discrete motive components. The laminate may be a combination of layers of a piezoelectrically active, nonconductive matrix material. A power source selectively places various levels of charge in electrically conductive filaments imbedded in the respective layers to produce various configurations in a predetermined manner. The layers may be electrically conductive having imbedded piezoelectrically active filaments. A combination of layers of electrically conductive material may be laminated to layers of piezoelectrically active material.

Kiraly, L. J. (inventor)

1983-01-01

190

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

191

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

192

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

NASA Astrophysics Data System (ADS)

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

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

2014-09-01

193

Recent advances of conductive adhesives as a lead-free alternative in electronic packaging: Materials, processing, reliability and applications  

Microsoft Academic Search

Tinlead solder alloys are widely used in the electronic industry. They serve as interconnects that provide the conductive path required to achieve connection from one circuit element to another. There are increasing concerns with the use of tinlead alloy solders in recognition of hazards of using lead. Lead-free solders and electrically conductive adhesives (ECAs) have been considered as the most

Yi Li; C. P. Wong

2006-01-01

194

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

195

Novel flip-chip bonding technology for W-band interconnections using alternate lead-free solder bumps  

Microsoft Academic Search

A novel lead-free flip-chip technology for mounting high-speed compound semiconductor ICs, which have a relatively severe limitation regarding high-heat treatment, is presented. Solder bump interconnections of 0.95Sn-0.05Au were successfully fabricated by reflowing multilayer metal film at as low a temperature as 220C. The bumps were designed to have a diameter of 36 ?m with a gap between the chip and

Kiyomitsu Onodera; Takao Ishii; Shinji Aoyama; Suehiro Sugitani; Masami Tokumitsu

2002-01-01

196

Assessing public exposure to silver-contaminated groundwater from lead-free solder: an upper bound, risk-based approach  

Microsoft Academic Search

The paper summarizes the results of a study to assess the potential human health risk associated with exposure to silver-contaminated groundwater from lead-free solder leachate. The specific alloy investigated is 96.3Sn\\/3.2Ag\\/0.7Cu. Silver transport in the groundwater is modeled using a one-dimensional advection-dispersion equation, and worst-case values for all system parameters have been chosen to provide a preliminary upper bound on

Eric R. Masanet

2002-01-01

197

Laser soldering of Sn-Ag-Cu and Sn-Zn-Bi lead-free solder pastes  

Microsoft Academic Search

It has reported that a waste of an electronics substrate including lead and its compound such as 63Sn-37Pb has polluted the environment with acid rain. For that environment problem the development of lead-free solder alloys has been promoted in order to find out the substitute for Sn-Pb solders in the United States, Europe, and Japan. In a present electronics industry,

Junichi Takahashi; Sumio Nakahara; Shigeyoshi Hisada; Takeyoshi Fujita

2004-01-01

198

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

Microsoft Academic Search

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

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

2005-01-01

199

Piezoelectric Polymer Shock Gauges  

NASA Astrophysics Data System (ADS)

The science and technology of piezoelectric materials has long been dominated by the availability of specific materials with particular properties. Piezoelectric PVDF (Poly(vinylidene fluoride) polymer and copolymers of PVDF with trifluoroethylene have shown to have the potential for new shock-wave sensors. Since 1981 through 1995, the piezoelectric response of PVDF was studied in a cooperative effort with Franois Bauer of ISL, France, R.A. Graham of Sandia National Laboratories and L.M. Lee of Ktech Corporation, Albuquerque. Among the known piezoelectric polymers, the PVDF plays an important role in measuring mechanical and physical state of matter under shock loading. The present paper presents the history of the development of the PVDF gauge. After 24 years of research in this area, main relevant results and data obtained are summarized as well as some original applications of the PVDF gauges.

Bauer, F.

2006-07-01

200

Piezoelectric Polymer Shock Gauges  

NASA Astrophysics Data System (ADS)

The science and technology of piezoelectric materials has long been dominated by the availability of specific materials with particular properties. Piezoelectric PVDF (Poly(vinylidene fluoride)) polymer and copolymers of PVDF with trifluoroethylene have shown that they have the potential for new shock-wave sensors. Since 1981 and until 1995, the piezoelectric response of PVDF has been studied in a cooperative effort with Francois Bauer of ISL, France, R.A. Graham of Sandia National Laboratories and L.M. Lee of the Ktech Corporation of Albuquerque. Among the known piezoelectric polymers, the PVDF plays an important role in measuring mechanical and physical state of matter under shock loading. The present paper presents the history of the development of the PVDF shock gauge. After 24 years of research in this area, main relevant results and data obtained are summarized as well as some of original applications of the PVDF gauges.

Bauer, Franois

2005-07-01

201

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

202

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

203

Laminated piezoelectric transformer  

NASA Technical Reports Server (NTRS)

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

Vazquez Carazo, Alfredo (Inventor)

2006-01-01

204

Porous Piezoelectric Ceramic Transducer  

Microsoft Academic Search

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

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

1991-01-01

205

Piezoelectric direct drive servovalve  

Microsoft Academic Search

A single-stage servovalve using direct piezoelectric actuator drive is described. The single-stage servovalve design offers higher bandwidth than conventional two-stage valves. It takes advantage of the high energy density in piezoelectric materials while addressing the need for internal amplification of stroke. When used alone, the valve can regulate pressure, and when used in combination with a hydraulic output device it

Jason E. Lindler; Eric H. Anderson

2002-01-01

206

Piezoelectrically Enhanced Photocathodes  

NASA Technical Reports Server (NTRS)

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

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

2011-01-01

207

Piezoelectric Energy Harvesting Solutions  

PubMed Central

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

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

2014-01-01

208

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

209

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

NASA Astrophysics Data System (ADS)

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

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

2011-11-01

210

Interdependence of processing and alloy composition on the reliability of Sn-based lead free solders in fine pitch FCOB interconnection  

Microsoft Academic Search

Market demands and legislation are driving the electronics manufacturing sector to move rapidly toward for a lead free future, with Pb containing electronics products are to be banned in Europe from 2006. The UK readiness for joining global actions to enable this 'green' packaging urgently requires the replacement of SnPb with suitable lead free alloys. Although the related scientific research

Zhiheng Huangl; Paul P. Conway; Changqing Liult; Rachel C. Thomson

2003-01-01

211

Investigation of the Effect of PCB Base Materials and Pad Surface Finish on the Thermal Fatigue Life of Lead-free Solder Joints of PBGA and Passive Resistors  

Microsoft Academic Search

Legislation that mandates the banning of lead in electronics due to environmental and health concerns has been actively pursued in many countries during the past fifteen years. Although a large number of research studies have been performed and are currently under way in the lead-free solder area, especially on the reliability of lead-free solder joints, abundant data exists predominantly on

Fubin Song; S. W. R. Lee; M. Osterman; M. Pecht

2006-01-01

212

Dynamics of Linear Piezoelectric Rods  

Microsoft Academic Search

A one-dimensional model of a linear piezoelectric thin rod is deduced from three-dimensional piezoelectricity by introducing suitable internal constraints and appropriate hypotheses on the electric displacement field.

F. Dav

1997-01-01

213

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

214

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

NASA Astrophysics Data System (ADS)

We report on the frequency and stress dependence of the direct piezoelectric d33 coefficient in BiFeO3 ceramics. The measurements reveal considerable piezoelectric nonlinearity, i.e., dependence of d33 on the amplitude of the dynamic stress. The nonlinear response suggests a large irreversible contribution of non-180 domain walls to the piezoelectric response of the ferrite, which, at present measurement conditions, reached a maximum of 38% of the total measured d33. In agreement with this interpretation, both types of non-180 domain walls, characteristic for the rhombohedral BiFeO3, i.e., 71 and 109, were identified in the poled ceramics using transmission electron microscopy. In support to the link between nonlinearity and non-180 domain-wall contribution, we found a correlation between nonlinearity and processes leading to depinning of domain walls from defects, such as quenching from above the Curie temperature and high-temperature sintering. In addition, the nonlinear piezoelectric response of BiFeO3 showed a frequency dependence that is qualitatively different from that measured in other nonlinear ferroelectric ceramics, such as "soft" (donor-doped) Pb(Zr,Ti)O3 (PZT), i.e., in the case of the BiFeO3 large nonlinearities were observed only at low field frequencies (<0.1 Hz); possible origins of this dispersion are discussed. Finally, we show that, once released from pinning centers, the domain walls can contribute extensively to the electromechanical response of BiFeO3; in fact, the extrinsic domain-wall contribution is relatively as large as in Pb-based ferroelectric ceramics with morphotropic phase boundary (MPB) composition, such as PZT. This finding might be important in the search of new lead-free MPB compositions based on BiFeO3 as it suggests that such compositions might also exhibit large extrinsic domain-wall contribution to the piezoelectric response.

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

2012-09-01

215

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

216

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.

217

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

218

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

219

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

220

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

NASA Astrophysics Data System (ADS)

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

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

2015-02-01

221

Laser soldering of Sn-Ag-Cu and Sn-Zn-Bi lead-free solder pastes  

NASA Astrophysics Data System (ADS)

It has reported that a waste of an electronics substrate including lead and its compound such as 63Sn-37Pb has polluted the environment with acid rain. For that environment problem the development of lead-free solder alloys has been promoted in order to find out the substitute for Sn-Pb solders in the United States, Europe, and Japan. In a present electronics industry, typical alloys have narrowed down to Sn-Ag-Cu and Sn-Zn lead-free solder. In this study, solderability of Pb-free solder that are Sn-Ag-Cu and Sn-Zn-Bi alloy was studied on soldering using YAG (yttrium aluminum garnet) laser and diode laser. Experiments were peformed in order to determine the range of soldering parameters for obtaining an appropriate wettability based on a visual inspection. Joining strength of surface mounting chip components soldered on PCB (printed circuit board) was tested on application thickness of solder paste (0.2, 0.3, and 0.4 mm). In addition, joining strength characteristics of eutectic Sn-Pb alloy and under different power density were examined. As a result, solderability of Sn-Ag-Cu (Pb-free) solder paste are equivalent to that of coventional Sn-Pb solder paste, and are superior to that of Sn-Zn-Bi solder paste in the laser soldering method.

Takahashi, Junichi; Nakahara, Sumio; Hisada, Shigeyoshi; Fujita, Takeyoshi

2004-10-01

222

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

223

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

224

Development of lead free magnetoelectric laminates of Na0.5Bi0.5TiO3-Tb0.3Dy0.7Fe1.95 for power generation  

NASA Astrophysics Data System (ADS)

Lead free magnetoelectric laminates has been prepared by sandwiching Sodium Bismuth Titanate (Na0.5Bi0.5TiO3) between two Tb0.3Dy0.7Fe1.95 (TDF) by epoxy bonding. The piezoelectric material Sodium Bismuth Titanate (Na0.5Bi0.5TiO3) has been prepared by conventional solid state double sintering method and the magnetostrictive material, Tb0.3Dy0.7Fe1.95 (TDF) by vacuum induction melting process. NBT showed a saturated ferroelectric hysteresis behavior with the values of Ps=22.24 ?C/cm2, Ec=41 kV/cm and Pr=27 ?C/cm2. The piezoelectric charge coefficient (d33) measured for NBT was 102 pC/N. Magnetization versus magnetic field measurements were performed in longitudinal (L) and transverse (T) modes of TDF specimen that showed ferromagnetic hysteresis behavior. The magnetostriction of 950 ppm at 4 kOe and static strain coefficient of 0.3710-6 kOe-1 at 1 kOe magnetic field were recorded for Tb0.3Dy0.7Fe1.95. The magnetoelectric output was measured in L and T modes for the different NBT thickness of 1.0, 1.5 and 2 mm with TDF thickness of 1.5 mm. The high magnetoelectric coefficient (?) was found to be 0.08 mV/cm Oe (L mode) and 0.13 mV/cm Oe (T mode) for the NBT/TDF laminates with 1.0 mm thick NBT.

Prabahar, K.; Mirunalini, Josephine; Sowmya, N. Shara; Chelvane, J. Arout; Mahendiran, M.; Kamat, S. V.; Srinivas, A.

2014-09-01

225

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

226

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

227

Piezoelectric direct drive servovalve  

NASA Astrophysics Data System (ADS)

A single-stage servovalve using direct piezoelectric actuator drive is described. The single-stage servovalve design offers higher bandwidth than conventional two-stage valves. It takes advantage of the high energy density in piezoelectric materials while addressing the need for internal amplification of stroke. When used alone, the valve can regulate pressure, and when used in combination with a hydraulic output device it forms part of an effective servohydraulic actuator. Development of a direct drive prototype valve is described. Discussion includes design issues related to low stroke smart material actuators such as piezoelectrics. Component and subsystem testing and results are reviewed. Electronic drive and control of the piezoelectric and overall device along with performance in the control of fluid flow is discussed. The value of the new servovalve is shown in the combination of the valve with a hydraulic output device. Data are supplied for this servohydraulic actuator. The new actuator shows promise for a motion simulator application and more generally for motion control at higher bandwidth than is possible with currently available servohydraulics.

Lindler, Jason E.; Anderson, Eric H.

2002-07-01

228

Qualification and optimization of Sn based soft solders: A refinement for Bi based lead free soft solders for EFM volume production  

Microsoft Academic Search

Continuous drive for environmental friendly manufacturing (EFM) has driven lead free soft solder to come on board at a larger scale world-wide since it was first debated publicly in 1999. Several renowned lead free soft solder suppliers have proposed Bi based soft solder as the most suitable candidate to replace the current widely used tin-lead (SnPb) solder. Experience with Bi

Bryan Y. Y. Ong; Lorong Enggang

2003-01-01

229

The characteristics of vibration fracture of Pb-Sn and lead-free Sn-Zn eutectic solders  

NASA Astrophysics Data System (ADS)

This work investigated the fatigue fracture characteristics of Sn-711wt.%Zn and Sn-3050wt.%PPb solder alloys under resonant vibration. For the alloys containing proeutectic Sn-rich grains, the results show stratum appearance on the deformation of coarse proeutectic grains. This stratum-type deformation will reduce the vibration resistance of Pb-Sn solder by inducing cracks. For the Sn-Zn system, fine eutectic structure will cause cracks to form and coalesce easily in the regions concentrated with small fibrous deformation grains, whereas hypereutectic structure shows coarse proeutectic Zn-rich particles as the crack initiation sites. Sn-t-Zn solders have better damping capacity than Pb-Sn solders. With hypoeutectic composition to induce stratum-type deformation and under lower vibration strain, these lead-free solders tend to exhibit superior crack propagation resistance, and, in that respect, are possible to replace Pb-Sn solders.

Chuang, C. M.; Lui, T. S.; Chen, L. H.

2001-09-01

230

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

SciTech Connect

With the advent of modern power electronics, embedded circuits and non-conventional energy harvesting, the need for high performance capacitors is bound to become indispensible. The current state-of-art employs ferroelectric ceramics and linear dielectrics for solid state capacitance. However, lead-free ferroelectric ceramics propose to offer significant improvement in the field of electrical energy storage owing to their high discharge efficiency and energy storage density. In this regards, the authors have investigated the effects of compressive stress as a means of improving the energy storage density of lead-free ferroelectric ceramics. The energy storage density of 0.91(Bi{sub 0.5}Na{sub 0.5})TiO{sub 3}-0.07BaTiO{sub 3}-0.02(K{sub 0.5}Na{sub 0.5})NbO{sub 3} ferroelectric bulk ceramic was analyzed as a function of varying levels of compressive stress and operational temperature .It was observed that a peak energy density of 387 mJ.cm{sup -3} was obtained at 100 MPa applied stress (25{sup o}C). While a maximum energy density of 568 mJ.cm{sup -3} was obtained for the same stress at 80{sup o}C. These values are indicative of a significant, 25% and 84%, improvement in the value of stored energy compared to an unloaded material. Additionally, material's discharge efficiency has also been discussed as a function of operational parameters. The observed phenomenon has been explained on the basis of field induced structural transition and competitive domain switching theory.

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

2014-08-15

231

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 (?30 mg/round) consisted primarily of metals such as Cu, Zn, and Fe along with soot arising from incomplete combustion. Nitrogen-containing heterocyclic aromatic compounds such as carbazole, quinolone, and phenazine were responsible for some of the 25 most significant chromatographic peaks, together with PAHs, diphenylamine, and phthalates. Emission factors were determined for PAHs and oxygenated PAHs; the latter were less abundant in the gun smoke particles than in domestic dust and diesel combustion smoke. This may be due to the oxygen-deficient conditions that occur when the gun is fired. By using an electrical low pressure impactor, it was demonstrated that more than 90% of the particles produced immediately after firing the weapon had diameters of less than 30 nm, and so most of the gun smoke particles belonged to the nanoparticle regime. PMID:24188168

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

2014-01-01

232

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

233

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

234

Improved Piezoelectric Loudspeakers And Transducers  

NASA Technical Reports Server (NTRS)

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

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

1995-01-01

235

High Temperature Piezoelectric Drill  

NASA Technical Reports Server (NTRS)

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

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

2012-01-01

236

Piezoelectrically actuated tunable capacitor  

Microsoft Academic Search

This paper describes the design, fabrication, and characterization of the first MEMS piezoelectric tunable capacitors employing zinc oxide (ZnO) actuation. Relatively simple design rules for the device-structure optimization for largest deflection are shown from simulation results based on theoretical equations. The ZnO-actuated tunable capacitors are accordingly designed and fabricated with both surface and bulk micromachining techniques. Through the surface micromachining

Chuang-Yuan Lee; Eun Sok Kim

2006-01-01

237

Piezoelectrically enhanced photocathode  

NASA Technical Reports Server (NTRS)

A photocathode, for generating electrons in response to incident photons in a photodetector, includes a base layer having a first lattice structure and an active layer having a second lattice structure and epitaxially formed on the base layer, the first and second lattice structures being sufficiently different to create a strain in the active layer with a corresponding piezoelectrically induced polarization field in the active layer, the active layer having a band gap energy corresponding to a desired photon energy.

Beach, Robert A. (Inventor); Nikzad, Shouleh (Inventor); Strittmatter, Robert P. (Inventor); Bell, Lloyd Douglas (Inventor)

2009-01-01

238

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

239

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

240

PIEZOELECTRIC POWER SCAVENGING OF MECHANICAL VIBRATION ENERGY  

E-print Network

PIEZOELECTRIC POWER SCAVENGING OF MECHANICAL VIBRATION ENERGY PIEZOELECTRIC POWER SCAVENGING OFPIEZOELECTRIC POWER SCAVENGING OF MECHANICAL VIBRATION ENERGYMECHANICAL VIBRATION ENERGY CE 511- Structural

Ervin, Elizabeth K.

241

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

242

Multimaterial piezoelectric fibres.  

PubMed

Fibre materials span a broad range of applications ranging from simple textile yarns to complex modern fibre-optic communication systems. Throughout their history, a key premise has remained essentially unchanged: fibres are static devices, incapable of controllably changing their properties over a wide range of frequencies. A number of approaches to realizing time-dependent variations in fibres have emerged, including refractive index modulation, nonlinear optical mechanisms in silica glass fibres and electroactively modulated polymer fibres. These approaches have been limited primarily because of the inert nature of traditional glassy fibre materials. Here we report the composition of a phase internal to a composite fibre structure that is simultaneously crystalline and non-centrosymmetric. A ferroelectric polymer layer of 30 mum thickness is spatially confined and electrically contacted by internal viscous electrodes and encapsulated in an insulating polymer cladding hundreds of micrometres in diameter. The structure is thermally drawn in its entirety from a macroscopic preform, yielding tens of metres of piezoelectric fibre. The fibres show a piezoelectric response and acoustic transduction from kilohertz to megahertz frequencies. A single-fibre electrically driven device containing a high-quality-factor Fabry-Perot optical resonator and a piezoelectric transducer is fabricated and measured. PMID:20622864

Egusa, S; Wang, Z; Chocat, N; Ruff, Z M; Stolyarov, A M; Shemuly, D; Sorin, F; Rakich, P T; Joannopoulos, J D; Fink, Y

2010-08-01

243

Piezoelectric wind turbine  

NASA Astrophysics Data System (ADS)

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

Kishore, Ravi Anant; Priya, Shashank

2013-03-01

244

Piezoelectric detection of photoacoustic signals  

Microsoft Academic Search

Piezoelectric detection of photoacoustic signals offers a number of advantages over the better known microphonic technique for condensed phase samples. Experimental techniques are greatly simplified by taking advantage of the acoustic impedence match offered by solid state detectors with solid or liquid samples. Such piezoelectric detectors prove suitable for a.c. steady state measurements as well as impulse-transient response detectors. Several

M. M. Farrow; R. K. Burnham; M. Auzanneau; S. L. Olsen; N. Purdie

1977-01-01

245

A Piezoelectric-Piezomagnetic Gyrator  

Microsoft Academic Search

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

M. Onoe; M. Sawabe

1962-01-01

246

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

247

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. PMID:24361928

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

2014-01-01

248

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

NASA Astrophysics Data System (ADS)

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

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

2013-03-01

249

Thickness dependence of hydrostatic piezoelectric properties of 13 piezoelectric composites  

Microsoft Academic Search

Thickness dependence of hydrostatic piezoelectric properties of 13 piezoelectric composites was studied. PZT rods with square cross section were used as piezoelectric active components. Epoxy resin was used as matrix. The volume fraction of piezoelectric ceramic was about 25%. The hydrostatic piezoelectric properties dh, gh and hydrostatic figure of merit dh gh are all dependent on the ratio of width

Li Denghua; Yao Xi

1999-01-01

250

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

251

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 10C 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 deliveron demandcontinuous vapor concentrations across more than six orders of magnitude (nominally 290fg/lto1.05?g/l). Vapor pulses containing femtogram to microgram quantities of analyte may also be generated. Calibrated ranges of three explosive vapors at ng/l levels were generated by the device and directly measured by ion mobility spectrometry (IMS). These data demonstrate expected linear trends within the limited working range of the IMS detector and also exhibit subtle nonlinear behavior from the IMS measurement process.

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

2006-08-01

252

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

NASA Astrophysics Data System (ADS)

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

Jiang, Li; Zhang, Guiying; Zhou, Jieming

2008-08-01

253

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

254

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

255

Asymmetric-hysteresis compensation in piezoelectric actuators  

NASA Astrophysics Data System (ADS)

The advantages of using piezoelectric actuators in ultra-precision applications are often impaired by nonlinear effects, in particular hysteresis, which may lead to positioning uncertainties of up to 15% of the actuator's stroke. Model-based compensation strategies are often prescribed in order to overcome this limitation and achieve better dynamical accuracy. This comes, however, at the expense of increasing identification and implementation complexity, especially when hysteresis is of the asymmetric type, such as prevalent in hard piezoceramic materials. This paper proposes a new compensation strategy based upon (i) treating hysteresis as being separate from other dynamical effects and (ii) formulating a new, simplified model to deal with asymmetric hysteresis, based on applying a linear operator to the conventional hysteresis models. After developing the theoretical background of the compensation strategy, the accuracy improvement due to the new hysteresis-compensation method is demonstrated experimentally.

Aguirre, Gorka; Janssens, Thierry; Van Brussel, Hendrik; Al-Bender, Farid

2012-07-01

256

Effect of intermetallic and Kirkendall voids growth on board level drop reliability for SnAgCu lead-free BGA solder joint  

Microsoft Academic Search

Lead free solder joints used in surface mount packages like ball grid array (BGA) have a great impact on the reliability of the end product. In accelerated thermal cycling (ATC) tests, cyclic excursions of temperatures cause concurrent degradation of the solder joint resulting in intermetallic compound (IMC) growth and thermal fatigue damage. The effect of thermal cycling aging on board

Luhua Xu; John H. L. Pang

2006-01-01

257

Radiation tolerance of piezoelectric bulk single-crystal aluminum nitride  

SciTech Connect

For practical use in harsh radiation environments, we pose selection criteria for piezoelectric materials for nondestructive evaluation (NDE) and material characterization. Using these criteria, piezoelectric aluminum nitride is shown to be an excellent candidate. The results of tests on an aluminumnitride-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 1018 neutron/cm2 and 5.8 1018 neutron/cm2, 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.

David A. Parks; Bernhard R. Tittmann

2014-07-01

258

Precision piezoelectric stepping motor using piezoelectric torsional actuator  

NASA Astrophysics Data System (ADS)

This paper deals with a newly developed piezoelectric motor that generates precise stepping motion using a piezoelectric torsional actuator and a pair of one-way clutch bearings. The torsional actuator consists of a piezoelectric cylinder that produces rotation motion invoking shear mode of piezoelectric materials and a torsion bar that magnifies the rotation angle produced from the piezoelectric cylinder. Inner one-way clutch bearing is fit on the torsion bar and outer bearing is mounted outside of the inner bearing such that when the torsion bar rotates in one direction, the inner bearing moves together while the outer one slips. When the torsion bar rotates in opposite direction, the inner bearing slips against the torsion bar while the outer bearing locks the inner bearing so as to accumulate the rotation angle. Because the elaborate piezoelectric torsional actuator functions as the driving source at high frequency, a precise step motion with high speed can be produced. The optimum condition for driving the motor is investigated in terms of excitation frequency, electrical impedance and the location of the bearing set. The rotation speed and torque of the motor is investigated, and 350 rpm and 0.19mNm torque are observed in maximum.

Kang, Byung-Woo; Kim, Jaehwan; Cheong, ChaeCheon; Yang, Bo-Won

2001-03-01

259

Piezoelectric MEMS for energy harvesting  

E-print Network

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

Kim, Sang-Gook

260

Composition design and electrical properties in (1-y)(K0.40Na0.60)0.985Li0.015(Nb1-xSbx)O3-yBi0.5Na0.5ZrO3 lead-free ceramics  

NASA Astrophysics Data System (ADS)

To realize the enhancement in piezoelectric activities, the composition-induced phase boundaries in (1-y)(K0.40Na0.60)0.985Li0.015(Nb1-xSbx)O3-yBi0.5Na0.5ZrO3 lead-free ceramics were designed and fabricated by the conventional solid-state method. We presented the evolutions of their phase structure, microstructure, and electrical properties with the change of Sb5+ and Bi0.5Na0.5ZrO3 contents. A rhombohedral-tetragonal phase boundary was successfully built in the composition region of 0.04 ? x ? 0.09 (y = 0.025) and 0.025 ? y ? 0.035 (x = 0.06), and then the desirable piezoelectric coefficients and bipolar strains (e.g., d33390 pC/N, kp0.45, Smax0.2%, and TC250 C) were simultaneously induced. We think that this may provide a direction of designing high-performance (K,Na)NbO3-based ceramics.

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

2015-02-01

261

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

262

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

NASA Astrophysics Data System (ADS)

Single-phase multiferroic Bi1-xNdxFeO3 (x=0-0.15) ceramics are polarized and their piezoelectric and pyroelectric effects are reported. The success in polarizing the ceramics originates from low electrical conductivities controlled predominantly by the Poole-Frenkel conduction mechanism. Limited internal traps due to reduced oxygen vacancies in the ceramics result in sufficiently low leakage current densities of <30mA/m2 even at a high electric field of 145kV/cm. The piezoelectric d33 coefficients of the ceramics before and after annealing at 550C for 4h are measured to be 28 and 24pC/N, respectively. These values are higher than those of most major lead-free high-temperature piezoelectric ceramics.

Yuan, G. L.; Or, Siu Wing

2006-02-01

263

Piezoelectric activity in Perovskite ferroelectric crystals.  

PubMed

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

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

2015-01-01

264

The Propagation of Rayleigh Waves in Layered Piezoelectric Structures with Viscosity  

E-print Network

The Propagation of Rayleigh Waves in Layered Piezoelectric Structures with Viscosity Jinxiang Shen propagation in resonators with viscosity of materials for solutions which can be used for the estimations of the viscosity, which usually is not the ideal value we can obtain from material testing. Not hard to imagine

Wang, Ji

265

Design and characterization of piezoelectric transformers for high power applications  

Microsoft Academic Search

A piezoelectric transformer (PT) is an electro-mechanical device that transfers electrical energy through a mechanical vibration at its resonance frequency. To improve the piezoelectric transformers in term of high density of transfer power, two types of piezoelectric transformers, a laminated piezoelectric transformer and an unipoled disk piezoelectric transformer, with radial extensional vibration mode were studied. For the laminated piezoelectric transformer,

Pitak Laoratanakul

2002-01-01

266

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

PubMed

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

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

2015-02-24

267

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

268

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

PubMed

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

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

2015-01-01

269

Intermetallic compounds formed at the interface between Cu substrate and an Sn-9Zn-0.5Ag lead-free solder  

SciTech Connect

The intermetallic compounds (IMCs) formed at the interface between Cu substrate and an Sn-9Zn-0.5Ag lead-free solder alloy have been investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM) and electron diffraction (ED). The XRD patterns show that the main IMCs formed at the interface of Sn-9Zn-0.5Ag/Cu are {gamma}-Cu{sub 5}Zn{sub 8} and {eta}'-Cu{sub 6}Sn{sub 5}. The Ag{sub 3}Sn IMC with orthorhombic structure was also observed at the Sn-9Zn-0.5Ag/Cu interface by TEM and ED analyses. The interfacial adhesion strength between the Cu substrate and Sn-9Zn-0.5Ag lead-free solder alloy is higher than that of the Sn-9Zn alloy due to the formation of Ag{sub 3}Sn IMC at the interface.

Chang, T.-C.; Hon, M.-H.; Wang, M.-C

2003-04-30

270

Measuring droplet impact with piezoelectric film  

E-print Network

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

Basahi, Jalal M. Al-Badry M.

1993-01-01

271

In-situ Non-destructive Ultrasonic Rheology Technique for Monitoring Different Lead-free Solder Pastes for Surface Mount Applications  

Microsoft Academic Search

This paper investigates the application of a non-destructive ultrasonic technique for characterising the rheological properties of solder paste through the use of through-mode microsecond ultrasonic pulses for evaluation of viscoelastic properties of lead-free solder paste containing different types of flux. Ultrasonic techniques offer a robust and reliable form of non-destructive testing of materials where access to the sample is restricted

A. Seman; N. N. Ekere; S. J. Ashenden; S. Mallik; A. E. Marks; R. Durairaj

2008-01-01

272

Modeling the interdependence of processing and alloy composition on the evolution of microstructure in Sn-based lead-free solders in fine pitch flip chip  

Microsoft Academic Search

Market demands and legislation are driving the electronics-manufacturing sector to move rapidly toward a lead-free future, with Pb-containing electronics products to be banned in Europe after 2006. Although the related scientific research has been undertaken for a decade, a number of technical complications still exist, which are further exacerbated due to the concurrent developments in miniaturization and multifunctionality of microelectronic

Zhiheng Huang; Paul P. Conway; Changqing Liu; Rachel C. Thomson

2006-01-01

273

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

274

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

NASA Astrophysics Data System (ADS)

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

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

2012-01-01

275

A comparison on the emission of polycyclic aromatic hydrocarbons and their corresponding carcinogenic potencies from a vehicle engine using leaded and lead-free gasoline.  

PubMed Central

Our objective in this study was to assess the effect of using two kinds of lead-free gasoline [including 92-lead-free gasoline (92-LFG) and 95-lead-free gasoline (95-LFG), rated according to their octane levels] to replace the use of premium leaded gasoline (PLG) on the emissions of polycyclic aromatic hydrocarbons (PAHs) and their corresponding benzo[a]pyrene equivalent (BaP(eq)) amounts from the gasoline-powered engine. The results show that the three gasoline fuels originally contained similar total PAHs and total BaP(eq) contents; however, we found significant differences in the engine exhausts in both contents. The above results suggest that PAHs originally contained in the gasoline fuel did not affect the PAH emissions in the engine exhausts. The emission factors of both total PAHs and total BaP(eq) obtained from the three gasoline fuels shared the same trend: 95-LFG > PLG > 92-LFG. The above result suggests that when PLG was replaced by 95-LFG, the emissions would increase in both total PAHs and total BaP(eq), but when replaced by 92-LFG would lead to the decreased emissions of both contents. By taking emission factors and their corresponding annual gasoline consumption rates into account, we found that both total PAH and total BaP(eq) emissions increased from 1994 to 1999. However, the annual increasing rates in total BaP(eq) emissions were slightly higher than the corresponding increasing rates in total PAHs. PMID:11748037

Mi, H H; Lee, W J; Tsai, P J; Chen, C B

2001-01-01

276

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

277

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

278

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

279

Fluoropolymer and Aluminum Piezoelectric Reactives  

NASA Astrophysics Data System (ADS)

The ability to sensitize a nanoaluminum/piezoelectric polymer composite has been studied using two fluoropolymer systems (THV220A and FC-2175). Fluoropolymers were chosen based on the presence of vinylidene fluoride (VDF) that is known to exhibit piezoelectric properties in certain phases. Reactive composite samples of the nanoaluminum/polymer were made into thin sheets and their ability to store energy and exhibit piezoelectric properties was measured. Also, initial drop weight impact tests were performed on the samples and results showed the piezoelectric energetic composites failed to ignite at a given impact energy. However, when a DC voltage was applied to the sample, the materials ignited at the previous impact energy indicating that the reactive composites may have been sensitized by the stored charge. The application of a DC voltage may also have an effect on the piezoelectric properties of the inorganic energetic composites. Further work is planned to investigate what parameters are inducing the sensitization of the material. A better understanding could lead to applications where switching or changing the sensitization of an energetic material is beneficial.

Janesheski, Robert; Son, Steven; Groven, Lori

2011-06-01

280

Closed-form solution for free vibration of piezoelectric coupled annular plates using Levinson plate theory  

NASA Astrophysics Data System (ADS)

Free vibration analysis of annular moderately thick plates integrated with piezoelectric layers is investigated in this study for different combinations of soft simply supported, hard simply supported and clamped boundary conditions at the inner and outer edges of the annular plate on the basis of the Levinson plate theory (LPT). The distribution of electric potential along the thickness direction in the piezoelectric layer is assumed as a sinusoidal function so that the Maxwell static electricity equation is approximately satisfied. The differential equations of motion are solved analytically for various boundary conditions of the plate. In this study the closed-form solution for characteristic equations, displacement components of the plate and electric potential are derived for the first time in the literature. To demonstrate the accuracy of the present solution, comparison studies is first carried out with the available data in the literature and then natural frequencies of the piezoelectric coupled annular plate are presented for different thickness-radius ratios, inner-outer radius ratios, thickness of piezoelectric, material of piezoelectric and boundary conditions. Present analytical model provides design reference for piezoelectric material application, such as sensors, actuators and ultrasonic motors.

Hosseini Hashemi, Sh.; Es'haghi, M.; Karimi, M.

2010-04-01

281

Dynamic analysis of tubular piezoelectric gyroscopes  

Microsoft Academic Search

The present article provides a theoretical and experimental research of piezoelectric gyroscopes based on the flexural vibrating modes of hollow piezoelectric cylinders. For different geometries, modal and harmonic analyses are conducted using ANSYS finite element software package. The sensitivity of piezoelectric gyroscopes and its correlation with geometrical and physical parameters of resonators are explored. The results obtained are compared with

Pavel S. Marinushkin

2010-01-01

282

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

PubMed

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

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

2012-06-01

283

Method of Fabricating a Piezoelectric Composite Apparatus  

NASA Technical Reports Server (NTRS)

A method for fabricating a piezoelectric macro-fiber composite actuator comprises providing a piezoelectric material that has two sides and attaching one side upon an adhesive backing sheet. The method further comprises slicing the piezoelectric material to provide a plurality of piezoelectric fibers in juxtaposition. A conductive film is then adhesively bonded to the other side of the piezoelectric material, and the adhesive backing sheet is removed. The conductive film has first and second conductive patterns formed thereon which are electrically isolated from one another and in electrical contact with the piezoelectric material. The first and second conductive patterns of the conductive film each have a plurality of electrodes to form a pattern of interdigitated electrodes. A second film is then bonded to the other side of the piezoelectric material. The second film may have a pair of conductive patterns similar to the conductive patterns of the first film.

Wilkie, W. Keats (Inventor); Bryant, Robert (Inventor); Fox, Robert L. (Inventor); Hellbaum, Richard F. (Inventor); High, James W. (Inventor); Jalink, Antony, Jr. (Inventor); Little, Bruce D. (Inventor); Mirick, Paul H. (Inventor)

2003-01-01

284

Piezoelectric materials used in underwater acoustic transducers  

SciTech Connect

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

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

2012-07-07

285

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

286

Vacuum mounting for piezoelectric transducers  

NASA Technical Reports Server (NTRS)

Special housing couples piezoelectric transducers to nonporous surfaces for ultrasonic or acoustic-emission testing. Device, while providing sound isolation on flat or nonflat surfaces, can be attached and detached quickly. Vacuum sealing mechanism eliminates need for permanent or semipermanent bonds, viscous coupling liquids, weights, magnets, tape, or springs ordinarily used.

Tiede, D. A.

1977-01-01

287

Fluoropolymer and aluminum piezoelectric reactives  

NASA Astrophysics Data System (ADS)

The ability to sensitize a nanoaluminum/piezoelectric polymer composite has been studied using two fluoropolymer systems (THV220A and FC-2175). Reactive composite samples of the nanoaluminum/polymer were made into thin sheets and their ability to store energy and exhibit piezoelectric properties was measured. Also, initial drop weight impact tests were performed on the samples and results showed the piezoelectric energetic composites failed to ignite at a given impact energy unless sensitized. When a DC voltage was applied to the sample, the materials ignited at the same impact energy where previous ignition failed. Results indicate that the reactive composites may have been sensitized by storing the applied charge. The application of a DC voltage may also have an effect on the piezoelectric properties of the energetic composites similar to the way poling techniques work. Further work is planned to investigate what parameters are inducing the sensitization of the material. A better understanding could lead to applications where switching or tuning the sensitization of an energetic material is beneficial.

Janesheski, Robert S.; Groven, Lori J.; Son, Steven

2012-03-01

288

Piezoelectric measurement of laser power  

DOEpatents

A method for measuring the energy of individual laser pulses or a series of laser pulses by reading the output of a piezoelectric (PZ) transducer which has received a known fraction of the total laser pulse beam. An apparatus is disclosed that reduces the incident energy on the PZ transducer by means of a beam splitter placed in the beam of the laser pulses.

Deason, Vance A. (Idaho Falls, ID); Johnson, John A. (Idaho Falls, ID); Telschow, Kenneth L. (Idaho Falls, ID)

1991-01-01

289

Circuit for Driving Piezoelectric Transducers  

NASA Technical Reports Server (NTRS)

The figure schematically depicts an oscillator circuit for driving a piezoelectric transducer to excite vibrations in a mechanical structure. The circuit was designed and built to satisfy application-specific requirements to drive a selected one of 16 such transducers at a regulated amplitude and frequency chosen to optimize the amount of work performed by the transducer and to compensate for both (1) temporal variations of the resonance frequency and damping time of each transducer and (2) initially unknown differences among the resonance frequencies and damping times of different transducers. In other words, the circuit is designed to adjust itself to optimize the performance of whichever transducer is selected at any given time. The basic design concept may be adaptable to other applications that involve the use of piezoelectric transducers in ultrasonic cleaners and other apparatuses in which high-frequency mechanical drives are utilized. This circuit includes three resistor-capacitor networks that, together with the selected piezoelectric transducer, constitute a band-pass filter having a peak response at a frequency of about 2 kHz, which is approximately the resonance frequency of the piezoelectric transducers. Gain for generating oscillations is provided by a power hybrid operational amplifier (U1). A junction field-effect transistor (Q1) in combination with a resistor (R4) is used as a voltage-variable resistor to control the magnitude of the oscillation. The voltage-variable resistor is part of a feedback control loop: Part of the output of the oscillator is rectified and filtered for use as a slow negative feedback to the gate of Q1 to keep the output amplitude constant. The response of this control loop is much slower than 2 kHz and, therefore, does not introduce significant distortion of the oscillator output, which is a fairly clean sine wave. The positive AC feedback needed to sustain oscillations is derived from sampling the current through the piezoelectric transducer. This positive AC feedback, in combination with the slow feedback to the voltage-variable resistors, causes the overall loop gain to be just large enough to keep the oscillator running. The positive feedback loop includes two 16-channel multiplexers, which are not shown in the figure. One multiplexer is used to select the desired piezoelectric transducer. The other multiplexer, which is provided for use in the event that there are significant differences among the damping times of the 16 piezoelectric transducers, facilitates changing the value of one of the resistors in the positive-feedback loop to accommodate the damping time of the selected transducer.

Randall, David P.; Chapsky, Jacob

2009-01-01

290

Interfacial Reactions of Sn58Bi and Sn9Zn Lead-Free Solders with Au\\/Ni\\/SUS304 Multilayer Substrate  

Microsoft Academic Search

The liquid\\/solid interfacial reactions of Sn-58Bi (SB) and Sn-9Zn (SZ) lead-free solders with Au\\/Ni\\/SUS304 multilayer substrates\\u000a have been investigated in this study. In the SB\\/Au\\/Ni\\/SUS304 couple, only the Ni3Sn4 phase with needle-like grains was formed at the SB\\/Au\\/Ni\\/SUS304 interface. The Ni5Zn21 phase with a column structure was formed at the SZ\\/Au\\/Ni\\/SUS304 interface. The thickness of both intermetallic compounds\\u000a (IMCs) increased

Yee-Wen Yen; Da-Wei Liaw; Kuen-Da Chen; Hao Chen

2010-01-01

291

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

292

Encapsulation of lead-free Sn\\/Zn\\/Bi solder alloy particles by coating with wax powder for improving oxidation resistance  

Microsoft Academic Search

An encapsulation treatment of lead-free Sn\\/Zn\\/Bi solder powder was investigated for improving the oxidation resistance. Sn-8mass%Zn-3mass%Bi\\u000a alloy particles were coated with a wax (12-hydroxystearic acid) powder by means of a dry mechanical treatment method using\\u000a a ball mill. In order to determine the optimum operating conditions of the ball mill in the wax-coating treatments, the compressive\\u000a energy required for deforming

Tomohiro Iwasaki; Jeong Hwan Kim; Shohei Mizuhashi; Munetake Satoh

2005-01-01

293

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.

294

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

295

Quantitative analysis of trace lead in tin-base lead-free solder by laser-induced plasma spectroscopy in air at atmospheric pressure.  

PubMed

A quantitative analysis of trace lead in tin-base lead-free solder was carried out with laser-induced plasma spectroscopy (LIPS). In order to evaluate the applicability of the technique for rapid in situ analytical purposes, measurements were performed in air at atmospheric pressure, and the emission characteristics of the plasma produced by a Q-switched Nd:YAG laser over a laser energy range of 10 - 90 mJ were investigated using time-resolved spectroscopy. The experimental results showed that the emission intensity of the analysis line (Pb I 405.78 nm) was maximized at a laser energy of around 30 mJ, and a time-resolved measurement of a spectrum with a delay time of 0.4 micros after the laser pulse was effective for reducing the background continuum. Based on the results, lead-free solder certified reference materials were analyzed for trace lead (concentration 174 - 1940 ppm), and a linear calibration curve was obtained with a detection limit of several tens ppm. PMID:18270425

Chen, Baozhong; Kano, Hidenori; Kuzuya, Mikio

2008-02-01

296

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

NASA Astrophysics Data System (ADS)

The electrocaloric effect was investigated in lead-free Zr doped Ba0.8Ca0.2(ZrxTi1-x)O3 (BCTZ) ceramics synthesized by a conventional sintering process. Room-temperature x-ray diffraction analysis showed that the tetragonal structure is obtained in BCTZ for x ? 0.08 and a pseudo cubic phase for x > 0.08. The dielectric spectroscopy and calorimetry revealed that the Curie temperature decreases as a consequence of Zr doping and that the BCTZ exhibits a first order ferroelectric phase transition. The electrocaloric effect was determined by the calculation of the electrocaloric change of temperature (?T) using the Maxwell relation based on the P-E hysteresis loops measured at different temperatures. A large electrocaloric responsivity ?T/?E = 0.34 10-6 Km/V was found for x = 0.04, which significantly exceeds of values found so far in other lead-free electrocaloric materials.

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

2015-01-01

297

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

SciTech Connect

Nowadays, lead-free ferroelectric materials have attracted much interest among materials scientists as a result of environmental concern. The bismuth germanate (Bi{sub 2}GeO{sub 5}) phase, one of the lead-free ferroelectric crystals, is of particular interest as its composition already contains good glass former (GeO{sub 2}) and can be prepared by an alternative glass ceramic route. In this work, the conventional melt-quenching method was used to produce the parent glass with composition of 60 mol% BiO{sub 1.5}:20 mol% GeO{sub 2}:20 mol% BO{sub 1.5}. The as-received glass pieces were subjected to the heat treatment schedule at various crystallization temperatures and dwell-times. The glass and glass ceramics samples were then investigated by XRD, Raman spectroscopy and their dielectric properties were also measured. The XRD and Raman spectroscopy showed that the crystallinity of the prepared glass ceramics depended very much on crystallization temperature and dwell-time. The larger dielectric constant and lower dielectric loss were obtained as crystallinity of the glass ceramics enhanced. The highest dielectric constant (epsilon{sub r}) was found at 77 with a low dielectric loss of about 0.005.

Kantha, P.; Pengpat, K.; Rujijanagul, G.; Tunkasiri, T.; Eitssayeam, S. [Department of Physics, Faculty of Science, Chiang Mai University, Chiang Mai 50202 (Thailand); Intatha, U. [School of Science, Mae Fha Luang University, Chiang Rai, 57100 (Thailand); Sirisoonthorn, S. [National Metal and Materials Technology Center, Klong Luang, Pathumthani 12120 (Thailand)

2009-07-23

298

Metastable monoclinic and orthorhombic phases and electric field induced irreversible phase transformation at room temperature in the lead-free classical ferroelectric BaTiO3  

NASA Astrophysics Data System (ADS)

For decades it has been a well-known fact that among the few ferroelectric compounds in the perovskite family, namely, BaTiO3, KNbO3, PbTiO3, and Na1 /2Bi1 /2TiO3 , the dielectric and piezoelectric properties of BaTiO3 are considerably higher than the others in polycrystalline form at room temperature. Further, similar to ferroelectric alloys exhibiting morphotropic phase boundary, single crystals of BaTiO3 exhibit anomalously large piezoelectric response when poled away from the direction of spontaneous polarization at room temperature. These anomalous features in BaTiO3 remained unexplained so far from the structural standpoint. In this work, we have used high-resolution synchrotron x-ray powder diffraction, atomic resolution aberration-corrected transmission electron microscopy, in conjunction with a powder poling technique, to reveal that at 300 K (i) the equilibrium state of BaTiO3 is characterized by coexistence of metastable monoclinic Pm and orthorhombic (Amm2) phases along with the tetragonal phase, and (ii) strong electric field switches the polarization direction from the [001] direction towards the [101] direction. These results suggest that BaTiO3 at room temperature is within an instability regime, and that this instability is the fundamental factor responsible for the anomalous dielectric and piezoelectric properties of BaTiO3 as compared to the other homologous ferroelectric perovskite compounds at room temperature. Pure BaTiO3 at room temperature is therefore more akin to lead-based ferroelectric alloys close to the morphotropic phase boundary where polarization rotation and field induced ferroelectric-ferroelectric phase transformations play a fundamental role in influencing the dielectric and piezoelectric behavior.

Kalyani, Ajay Kumar; Khatua, Dipak Kumar; Loukya, B.; Datta, Ranjan; Fitch, Andy N.; Senyshyn, Anatoliy; Ranjan, Rajeev

2015-03-01

299

Finite Element Analysis of Piezoelectric Ceramic Speaker with Ansys Software  

E-print Network

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

Wang, Ji

300

Microstructure-property interactions in piezoelectric composites  

SciTech Connect

Piezoelectric composites have recently attracted extensive attention in view of their wide applications to smart sensors and actuators. A micromechanics model is developed to predict the coupled electro-thermo-elastic properties of a broad class of two-phase piezoelectric composites. The composites are modeled as infinite piezoelectric solids containing periodically distributed piezoelectric inhomogeneities with arbitrary shape. The elastic, thermal, and electric fields within such periodic composites can be expressed in Fourier series. The interactions between inhomogeneities are thus accounted for in an explicit and direct manner. By using Eshelby`s equivalent inclusion method, analytic estimates for the overall elastic, piezoelectric, dielectric and thermal properties of a broad class of piezoelectric composites are obtained. Important microstructural variables, such as the properties and shape of inhomogeneity, are studied. The results agree very well with experimental data and are also compared with those obtained by existing micromechanics models, such as self-consistent method and Mori-Tanaka method.

Yu, N. [Univ. of Tennessee, Knoxville, TN (United States)

1995-12-31

301

Improvement of Temperature Dependence of Piezoelectric Elements  

NASA Astrophysics Data System (ADS)

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

Nagata, Kunihiro; Harashima, Eiki

1994-09-01

302

Electric properties of Holmium substituted SrBi4Ti4O15ceramic for High Temperature Piezoelectric Applications  

Microsoft Academic Search

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

P. Sarah

2011-01-01

303

Modeling of nonlinear piezoelectric behavior  

NASA Astrophysics Data System (ADS)

A finite element model for the nonlinear behavior of piezoelectric material is developed. Important issues in modeling the nonlinear behavior of piezoelectric material at micro-scale is discussed and methods to solve such issues are proposed. A procedure is developed to obtain RVE from the simplified microstructure of the material. The RVE is obtained based on a statistical parameter, which is a measure of the degree of heterogeneity at a point. The material properties at the micro-scale are obtained from the macro-scale properties by rule of mixture approach. A finite element iterative solution procedure is then used to model the material behavior by averaging the local response over the entire RVE. Nonlinear behavior of the material is due to the domain switching phenomenon and is simulated based on internal energy density based switching criterion. A numerical example is given for PZT-4 material and the results agree qualitatively with the experimental results.

Achuthan, Ajit; Sun, Chin-Teh

2002-07-01

304

Fracture mechanics for piezoelectric ceramics  

NASA Astrophysics Data System (ADS)

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

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

1992-05-01

305

A Piezoelectric Cryogenic Heat Switch  

NASA Technical Reports Server (NTRS)

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 greater than 100 were achieved when the positioner applied its maximum force of 8 N. We discuss the advantages of using this system in cryogenic applications, and estimate the ultimate performance of an optimized PZHS.

Jahromi, Amir E.; Sullivan, Dan F.

2014-01-01

306

Piezoelectric immunosensors -- Theory and applications  

SciTech Connect

A Mini Review of recent advances in piezoelectric immunobiosensors is presented. First a review of the theory and history of the technique is given, followed by a critical survey of the use of this method in various fields of analysis. A biosensor can be defined as a device incorporating biological material connected to or integrated within a transducer. The specificity and sensitivity is complemented by the transducer, which electronically measures and computes the signal.

O`Sullivan, C.K.; Vaughan, R.; Guilbault, G.G. [Univ. Coll. Cork (Ireland). Dept. of Chemistry

1999-09-01

307

Angularly inhomogeneous piezoelectric piezomagnetic magnetoelectric anisotropic media  

Microsoft Academic Search

The field around a line defect along the axis of an angularly inhomogeneous, elastically anisotropic medium with piezoelectric, piezomagnetic and magnetoelectric coupling has a surprisingly simple form.

V. I. Alshits; H. O. K. Kirchner; T. C. T. Ting

1995-01-01

308

Piezoelectric transformer structural modeling--a review.  

PubMed

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

Yang, Jiashi

2007-06-01

309

Process Development and Solder Joint Reliability of a New Lead-Free Solder: Sn3wt%Ag0.5wt%Cu0.019wt%Ce (SACC)  

Microsoft Academic Search

The effects of a very low level (0.019wt%) of doping of Ce (cerium) on the SnAgCu (SAC) solder joints of lead-free PQFP (plastic quad flat pack), PBGA (plastic ball grid array), wafer-level chip scale package (WLCSP), and BCC (bumped chip carrier) components on lead-free PCB (printed circuit boards) are investigated in this study. Emphasis is placed on the PCA (PCB

John Lau; Sang Liu; Dongkai Shangguan; Zhi Wei Song; David Geiger

2007-01-01

310

Modeling and analysis of 96.5Sn3.5Ag lead-free solder joints of wafer level chip scale package on buildup microvia printed circuit board  

Microsoft Academic Search

In this study, time-temperature-dependent nonlinear analyses of lead-free solder bumped wafer level chip scale package (WLCSP) on microvia buildup printed circuit board (PCB) assemblies subjected to thermal cycling conditions are presented. The lead-free solder considered is 96.5Sn-3.5Ag. The 62Sn-2Ag-36Pb solder is also considered to establish a baseline. These two solder alloys are assumed to obey the Garofalo-Arrhenius steady-state creep constitutive

John H. Lau; S.-W. R. Lee

2002-01-01

311

Interfacial Reactions of Sn-58Bi and Sn-9Zn Lead-Free Solders with Au/Ni/SUS304 Multilayer Substrate  

NASA Astrophysics Data System (ADS)

The liquid/solid interfacial reactions of Sn-58Bi (SB) and Sn-9Zn (SZ) lead-free solders with Au/Ni/SUS304 multilayer substrates have been investigated in this study. In the SB/Au/Ni/SUS304 couple, only the Ni3Sn4 phase with needle-like grains was formed at the SB/Au/Ni/SUS304 interface. The Ni5Zn21 phase with a column structure was formed at the SZ/Au/Ni/SUS304 interface. The thickness of both intermetallic compounds (IMCs) increased with increasing reaction temperature and time. Meanwhile, the growth mechanism of these two IMCs is seen to follow a parabolic law and is diffusion controlled.

Yen, Yee-Wen; Liaw, Da-Wei; Chen, Kuen-Da; Chen, Hao

2010-11-01

312

Microstructure and Sn crystal orientation evolution in Sn-3.5Ag lead-free solders in high temperature packaging applications  

SciTech Connect

Understanding the reliability of eutectic Sn-3.5Ag lead-free solders in high temperature packaging applications is of significant interest in power electronics for the next generation electric grid. Large area (2.5mm 2.5mm) Sn-3.5Ag solder joints between silicon dies and direct bonded copper substrates were thermally cycled between 5 C and 200 C. Sn crystal orientation and microstructure evolution during thermal cycling were characterized by electron backscatter diffraction (EBSD) in scanning electron microscope (SEM). Comparisons are made between observed initial texture and microstructure and its evolution during thermal cycling. Gradual lattice rotation and grain boundary misorientation evolution suggested the continuous recrystallization mechanism. Recrystallization behavior was correlated with dislocation slip activities.

Zhou, Bite [ORNL; Muralidharan, Govindarajan [ORNL; Kurumaddali, Nalini Kanth [ORNL; Parish, Chad M [ORNL; Leslie, Dr Scott [Powerex Inc; Bieler, T. R. [Michigan State University, East Lansing

2014-01-01

313

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

NASA Astrophysics Data System (ADS)

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

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

2009-05-01

314

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

NASA Astrophysics Data System (ADS)

Compared with the traditional actuator of machinery and electricity, the piezoelectric actuator has the advantages of a compact structure, small volume, no mechanical friction, athermancy and no electromagnetic interference. Therefore, it has high application value in the fields of MEMS, bioengineering, medical science and so on. This article draws conclusions from the influence of multiple piezoelectric effects on the physical parameters (dielectric coefficient, equivalent capacity, energy conversion and piezoelectric coefficient) of piezoelectric actuators. These data from theoretical and experimental research show the following: (1) The rate between the dielectric coefficient of piezoelectric in mechanical freedom and clamping is obtained from the secondary direct piezoelectric effect, which enhances the dielectric property, increases the dielectric coefficient and decreases the coefficient of dielectric isolation; (2) Under external field, En ( ex ) = E 1 , exterior stress T = 0, that is to say, under the boundary condition of mechanical freedom, piezoelectric can store electric energy and elasticity, which obtains power density, elastic density and an electromechanical coupling factor; (3) According to the piezoelectric strain Si ( 1 ) , piezoelectric displacement Dm ( 2 ) and piezoelectric strain Si ( 3 ) of multiple piezoelectric effects, when the dielectric coefficient of the first converse piezoelectric effect ?33 is 1326 and the dielectric coefficient of the secondary direct piezoelectric effect increases to 3336, the dielectric coefficient of the ceramic chip increases. When the piezoelectric coefficient of the first converse piezoelectric effect d33 is 595 and the piezoelectric coefficient of the secondary direct piezoelectric effect decreases to 240, the piezoelectric coefficient of the ceramic chip will decrease. It is of major significance both in the applications and in basic theory to research the influence of multiple piezoelectric effects on the physical parameters of piezoelectric actuators. On the one hand, this can further increase the control precision of piezoelectric actuators. On the other hand, it can be applied to research on the physical parameters and self-sensing actuators, like piezoelectric quartz and piezoelectric ceramic self-sensing actuators, which will be of great service for MEMS.

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

2015-04-01

315

Love waves in functionally graded piezoelectric materials  

Microsoft Academic Search

To investigate the features of Love waves in a layered functionally graded piezoelectric structure, the mathematical model is established on the basis of the elastic wave theory, and the WKB method is applied to solve the coupled electromechanical field differential equation. The solutions of the mechanical displacement and electrical potential function are obtained for the piezoelectric layer and elastic substrate.

X. Y. Li; Z. K. Wang; S. H. Huang

2004-01-01

316

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

317

Optimal impedance design for piezoelectric vibration control  

Microsoft Academic Search

Piezoelectric transducers are commonly used as strain actuators in the control of mechanical vibration. One control strategy, termed piezoelectric shunt damping, involves the connection of an electrical impedance to the terminals of a structurally bonded transducer. Many passive, nonlinear, and semi-active impedance designs have been proposed that reduce structural vibration. The paper introduces a new technique for the design and

Andrew J. Fleming; S. O. Reza Moheimani

2004-01-01

318

Optimal Materials Selection for Bimaterial Piezoelectric Microactuators  

Microsoft Academic Search

Piezoelectric actuation is one of the commonly employed actuation schemes in microsystems. This paper focuses on identifying and ranking promising active material\\/substrate combinations for bimaterial piezoelectric (BPE) microactuators based on their performance. The mechanics of BPE structures following simple beam theory assumptions available in the literature are applied to evolve critical performance metrics which govern the materials selection process. Contours

Prasanna Srinivasan; S. Mark Spearing

2008-01-01

319

High temperature, high power piezoelectric composite transducers.  

PubMed

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

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

2014-01-01

320

Dynamics of active piezoelectric damping composites  

Microsoft Academic Search

A finite element model is developed to investigate the dynamic characteristics of beams treated with discrete patches of Active Piezoelectric Damping Composites (APDC). The APDC patches, under consideration, consist of piezoelectric rods that are obliquely embedded in a viscoelastic matrix to actively control its shear and compression damping characteristics. With such active and passive control capabilities, the energy dissipation mechanism

M. Arafa; A. Baz

2000-01-01

321

Longitudinal wave propagation in piezoelectric coupled rods  

Microsoft Academic Search

This paper presents the results of longitudinal wave propagation in piezoelectric coupled rod structures. The deduction of non-dispersive or dispersive characteristics of the structures is based on a classical rod model and the Mindlin-Herrmann rod model. In the classical model, correction factors for piezoelectric effects are introduced to provide remedy for the discontinuity of the normal stress at the interface

Q. Wang; V. K. Varadan

2002-01-01

322

PVPF control of piezoelectric tube scanners  

Microsoft Academic Search

As in most applications of nanotechnology speed and precision are important requirements for getting good topographical maps of material surfaces using Scanning Tunneling Microscopes (STM) and Atomic Force Microscopes (AFM). Many STMs and AFMs use Piezoelectric tubes for scanning and positioning with nanometer resolution. In this work a piezoelectric tube of the type typically used in STMs and AFMs is

B. Bhikkaji; M. Ratnam; S. O. R. Moheimani

2006-01-01

323

PVPF control of piezoelectric tube scanners  

Microsoft Academic Search

As in most applications of nanotechnology, speed and precision are important requirements for getting good topographical maps of material surfaces using Scanning Tunneling Microscopes (STM) and Atomic Force Microscopes (AFM). Many STMs and AFMs use piezoelectric tubes for scanning and positioning with nanometer resolution. In this work a piezoelectric tube of the type typically used in STMs and AFMs is

B. Bhikkaji; M. Ratnam; S. O. R. Moheimani

2007-01-01

324

LC Circuits for Diagnosing Embedded Piezoelectric Devices  

NASA Technical Reports Server (NTRS)

A recently invented method of nonintrusively detecting faults in piezoelectric devices involves measurement of the resonance frequencies of inductor capacitor (LC) resonant circuits. The method is intended especially to enable diagnosis of piezoelectric sensors, actuators, and sensor/actuators that are embedded in structures and/or are components of multilayer composite material structures.

Chattin, Richard L.; Fox, Robert Lee; Moses, Robert W.; Shams, Qamar A.

2005-01-01

325

Passive modal damping with piezoelectric shunts  

Microsoft Academic Search

The use of piezoelectric materials in conjunction with passive inductance-resistance-capacitance (RLC) circuits to dampen specific vibration modes is explored. The piezoelectric materials convert mechanical energy to electrical energy, which is then dissipated in the RLC circuit through joule heating. An impulse is applied to a simple cantilevered beam and by varying the inductance and resistance values, the natural oscillation frequency

John J. Granier; R. Jason Hundhausen; Gabriel E. Gaytan

2001-01-01

326

Experiments to Demonstrate Piezoelectric and Pyroelectric Effects  

ERIC Educational Resources Information Center

Piezoelectric and pyroelectric materials are used in many current applications. The purpose of this paper is to explain the basic properties of pyroelectric and piezoelectric effects and demonstrate them in simple experiments. Pyroelectricity is presented on lead zirconium titanate (PZT) ceramics as an electric charge generated by the temperature

Erhart, Jir

2013-01-01

327

High Temperature, High Power Piezoelectric Composite Transducers  

PubMed Central

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

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

2014-01-01

328

Modeling nonlinear behavior in a piezoelectric actuator  

Microsoft Academic Search

A piezoelectric tube actuator is employed as a sample positioning device in Nanocut, a cutting instrument conceived to study the mechanics of nanometric cutting. Extension of functionality of the instrument as a nanometric machine tool motivates the search for an accurate model of the actuator for implementing feedback control. A simple nonlinear model describing longitudinal expansion of the piezoelectric tube

H. Richter; E. A. Misawa; D. A. Lucca; H. Lu

2001-01-01

329

Damping control of 'smart' piezoelectric shell structures  

NASA Astrophysics Data System (ADS)

Advanced 'smart' structures with self-sensation and control capabilities have attracted much attention in recent years. 'Smart' piezoelectric structures (conventional structures integrated with piezoelectric sensor and actuator elements) possessing self-monitoring and adaptive static and/or dynamic characteristics are very promising in many applications. This paper presents a study on 'smart' piezoelectric shell structures. A generic piezoelastic vibration theory for a thin piezoelectric shell continuum made of a hexagonal piezoelectric material is first derived. Piezoelastic system equation and electrostatic charge equation are formulated using Hamilton's principle and Kirchhoff-Love thin shell assumptions. Dynamic adaptivity, damping control, of a simply supported cylindrical shell structure is demonstrated in a case study. It shows that the system damping increases with the increase of feedback voltage for odd modes. The control scheme is ineffective for all even modes because of the symmetrical boundary conditions.

Tzou, H. S.

330

Temperature Distributions in Piezoelectric Photothermal Spectroscopy  

NASA Astrophysics Data System (ADS)

Piezoelectric photothermal spectroscopy is a method in which the stress and strain of a sample due to the absorption of electromagnetic radiation is detected by a piezoelectric transducer. The temperature distribution in the sample is the basis to obtain the theoretical amplitude and phase of photothermal piezoelectric spectra. In contrast to microphone detection, which needs only the temperature at one of the sample surfaces, in the piezoelectric one, it is necessary to know the spatial temperature distribution. The distributions given by Blonskij and by the modified interferential model of Malinski are applied. The influence of defect states in a volume and at the surfaces on the character of the amplitude and phase piezoelectric spectra is analyzed. The comparison of these approximate models and the two-layer one of Fernelius is presented.

Zakrzewski, J.; Mali?ski, M.; Strza?kowski, K.

2013-04-01

331

Network representation for piezoelectric bimorphs.  

PubMed

The networks associated with the bimorph matrix are presented. The bimorph matrix is diagonalized and eigenvalues and eigenstates are found for the extremes of nonpiezoelectric and strong piezoelectric coupling. A physical interpretation of the eigenvalues and eigenstates is proposed. The bimorph matrix is also diagonalized through elementary operation matrices, which give the matrix in equivalent form. The transformation matrices are of upper triangular form. This transformation yields networks of the simplest possible connection schemes. It is shown that when fewer than the maximum number of boundary conditions are applied, the networks are easily simplified. The networks of the admittance and impedance matrix are presented. PMID:18267624

Ballato, A; Smits, J G

1991-01-01

332

Fabrication of Piezoelectric Cellulose Paper and Audio Application  

Microsoft Academic Search

We report the fabrication process of piezoelectric cellulose paper and the enhancement method of its piezoelectric property. Stretching method with different wet-drawing ratios was introduced to increase the piezoelectric property of cellulose paper during regeneration process. It is observed that the Young's modulus and the piezoelectric charge constants are very dependent on the drawing ratio and the direction of nanofibrils

Jung-Hwan Kim; Sungryul Yun; Joo-Hyung Kim; Jaehwan Kim

2009-01-01

333

Direct observation of intrinsic piezoelectricity of Pb(Zr,Ti)O{sub 3} by time-resolved x-ray diffraction measurement using single-crystalline films  

SciTech Connect

Lead zirconate titanate, Pb(Zr,Ti)O{sub 3} or PZT, is one of the most widely investigated ferroelectric and piezoelectric materials due to its superior properties. However, the intrinsic properties of PZT have not been directly measured due to the lack of fabrication of single crystals even though a basic understanding of intrinsic properties has been of interest developing lead-free piezoelectric materials. We demonstrated the direct observation of the intrinsic piezoelectric property by means of the detection of electric-field induced crystal lattice distortion of thick Pb(Zr{sub 0.35}Ti{sub 0.65})O{sub 3} single-crystalline films with single polar-axis orientation and negligible residual strain using the time-resolved X-ray diffraction (XRD) together with the polarization response. Consequently, the effective converse piezoelectric response was experimentally revealed; hence, the electrostrictive coefficient, which is the conversion coefficient between the electrical and mechanical response, was determined. The obtained effective electrostrictive coefficient was 5.26.3??10{sup ?2} m{sup 4}/C{sup 2}, which agrees with theoretical prediction.

Fujisawa, Takashi; Ehara, Yoshitaka; Yasui, Shintaro; Kamo, Takafumi; Funakubo, Hiroshi, E-mail: funakubo@iem.titech.ac.jp [Department of Innovative and Engineered Materials, Tokyo Institute of Technology, J2-1508, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8502 (Japan); Yamada, Tomoaki [Department of Innovative and Engineered Materials, Tokyo Institute of Technology, J2-1508, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8502 (Japan); Department of Materials, Physics and Energy Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); PRESTO, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012 (Japan); Sakata, Osami [Synchrotron X-ray Station at SPring-8, National Institute for Materials Science (NIMS), Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan); Japan Synchrotron Radiation Research Institute, SPring-8, Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan)

2014-07-07

334

Structural observation of piezoelectric inhomogeneity in a mixed-orientation Na0.5Bi0.5TiO3 perovskite thin film  

NASA Astrophysics Data System (ADS)

Thin films of the lead-free ferroelectric Na0.5Bi0.5TiO3 grown on thin-film Pt electrodes supported by SrTiO3 substrates have a complex microstructure consisting of crystalline grains with three distinct major crystallographic orientations. The piezoelectric response measured in spatially separated sub-micron grains using time-resolved synchrotron x-ray microdiffraction is highly inhomogeneous even among grains sharing the same major orientation. The piezoelectric coefficient d33 varies by nearly a factor of two in a series of areas sharing the <001> orientation. The piezoelectric inhomogeneity is linked to the peculiar microstructure of the film, arising from local variations in the stress imposed by surrounding grains with different crystallographic orientations and differing directions of the ferroelectric remnant polarization. A systematic nonlinearity of the piezoelectric strain is observed in applied electric fields with small magnitudes in all regions, consistent with the coexistence of domains of differing polarization direction at zero applied electric field.

Carbone, D.; Pateras, A. I.; Bussone, G.; Evans, P. G.; Cornelius, T. W.; Bousquet, M.; Boulle, A.; Gautier, B.; Duclre, J. R.

2014-12-01

335

Using Diffusion Bonding in Making Piezoelectric Actuators  

NASA Technical Reports Server (NTRS)

A technique for the fabrication of piezoelectric actuators that generate acceptably large forces and deflections at relatively low applied voltages involves the stacking and diffusion bonding of multiple thin piezoelectric layers coated with film electrodes. The present technique stands in contrast to an older technique in which the layers are bonded chemically, by use of urethane or epoxy agents. The older chemical-bonding technique entails several disadvantages, including the following: It is difficult to apply the bonding agents to the piezoelectric layers. It is difficult to position the layers accurately and without making mistakes. There is a problem of disposal of hazardous urethane and epoxy wastes. The urethane and epoxy agents are nonpiezoelectric materials. As such, they contribute to the thickness of a piezoelectric laminate without contributing to its performance; conversely, for a given total thickness, the performance of the laminate is below that of a unitary piezoelectric plate of the same thickness. The figure depicts some aspects of the fabrication of a laminated piezoelectric actuator by the present diffusion- bonding technique. First, stock sheets of the piezoelectric material are inspected and tested. Next, the hole pattern shown in the figure is punched into the sheets. Alternatively, if the piezoelectric material is not a polymer, then the holes are punched in thermoplastic films. Then both faces of each punched piezoelectric sheet or thermoplastic film are coated with a silver-ink electrode material by use of a silkscreen printer. The electrode and hole patterns are designed for minimal complexity and minimal waste of material. After a final electrical test, all the coated piezoelectric layers (or piezoelectric layers and coated thermoplastic films) are stacked in an alignment jig, which, in turn, is placed in a curved press for the diffusion-bonding process. In this process, the stack is pressed and heated at a specified curing temperature and pressure for a specified curing time. The pressure, temperature, and time depend on the piezoelectric material selected. At the end of the diffusion-bonding process, the resulting laminated piezoelectric actuator is tested to verify the adequacy of the mechanical output as a function of an applied DC voltage.

Sager, Frank E.

2003-01-01

336

Steerable Adaptive Bullet (StAB) piezoelectric flight control system  

NASA Astrophysics Data System (ADS)

This paper outlines a new class of piezoelectric flight control actuators which are specifically intended for use in guided hard-launched munitions from under 5.56mm to 40mm in caliber. In March of 2011, US Pat. 7,898,153 was issued, describing this new class of actuators, how they are mounted, laminated, energized and used to control the flight of a wide variety of munitions. This paper is the technical conference paper companion to the Patent. A Low Net Passive Stiffness (LNPS) Post Buckled Precompressed (PBP) piezoelectric actuator element for a 0.40 caliber body, 0.50 caliber round was built and tested. Aerodynamic modeling of the flight control actuator showed that canard deflections of just +/-1 are more than sufficient to provide full flight control against 99% atmospherics to 2km of range while maintaining just 10cm of dispersion with lethal energy pressure levels upon terminal contact. Supersonic wind tunnel testing was conducted as well as a sweep of axial compression. The LNPS/PBP configuration exhibited an amplification factor of 3.8 while maintaining equivalent corner frequencies in excess of 100 Hz and deflection levels of +/-1. The paper concludes with a fabrication and assembly cost analysis on a mass production scale.

Barrett, Ron; Barnhart, Ryan; Bramlette, Richard

2012-04-01

337

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

NASA Astrophysics Data System (ADS)

Here, a strip-shaped 2-2 cement/polymer-based piezoelectric composite was designed and fabricated. The dielectric, piezoelectric and electromechanical coupling properties of the composite were investigated as well as the coupling effects between the thickness and lateral modes of the piezoelectric composites. The dielectric and piezoelectric properties of the composites can be greatly influenced by variations of the piezoelectric ceramic volume fraction and the structural dimensions of the composites. Excellent properties have been achieved for ultrasonic transducer applications in civil engineering monitoring fields, such as large piezoelectric voltage constants, high thickness electromechanical coupling coefficients and low acoustic impedance. The damping property of the composites was especially studied. The maximum damping loss factor of the composites is between 0.280.32, and the glass transition temperature is between 5566 C.

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

2015-02-01

338

Piezoelectric voltage coupled reentrant cavity resonator  

NASA Astrophysics Data System (ADS)

A piezoelectric voltage coupled microwave reentrant cavity has been developed. The central cavity post is bonded to a piezoelectric actuator allowing the voltage control of small post displacements over a high dynamic range. We show that such a cavity can be implemented as a voltage tunable resonator, a transducer for exciting and measuring mechanical modes of the structure, and a transducer for measuring comparative sensitivity of the piezoelectric material. Experiments were conducted at room and cryogenic temperatures with results verified using Finite Element software.

Carvalho, N. C.; Fan, Y.; Le Floch, J.-M.; Tobar, M. E.

2014-10-01

339

Piezoelectric voltage coupled reentrant cavity resonator.  

PubMed

A piezoelectric voltage coupled microwave reentrant cavity has been developed. The central cavity post is bonded to a piezoelectric actuator allowing the voltage control of small post displacements over a high dynamic range. We show that such a cavity can be implemented as a voltage tunable resonator, a transducer for exciting and measuring mechanical modes of the structure, and a transducer for measuring comparative sensitivity of the piezoelectric material. Experiments were conducted at room and cryogenic temperatures with results verified using Finite Element software. PMID:25362432

Carvalho, N C; Fan, Y; Le Floch, J-M; Tobar, M E

2014-10-01

340

A piezoelectric pseudo-bimorph actuator  

NASA Astrophysics Data System (ADS)

We report a piezoelectric pseudo-bimorph actuator, which is made of only one single plate with interdigitated electrodes on both sides and polarized alternately in longitudinal direction. Like a bimorph actuator, it can also produce a large bending actuation based on anti-symmetrically longitudinal piezoelectric d33 strain effect under an applied electric field. The presented pseudo-bimorph actuator shows much better temperature stability than conventional piezoelectric bimorph actuators from room temperature to the depolarization temperature of the material due to lacking of interface strain loss.

Shi, Huaduo; Chen, Jianguo; Liu, Guoxi; Xiao, Wenlei; Dong, Shuxiang

2013-06-01

341

A traveling wave piezoelectric beam robot  

NASA Astrophysics Data System (ADS)

In this paper, the operation principles of a traveling wave piezoelectric beam robot are presented. A prototype consisting of an aluminum beam structure, with two non-collocated piezoelectric patches bonded on its surface, was fabricated and tested to demonstrate the generation of a traveling wave on the beam based on the one mode excitation and the two mode excitation operation principles for propulsion. A numerical model was developed and used to study and optimize the generated motion of the piezoelectric beam robot. Experimental characterization of the robot for the two types of operation has been carried out, a comparison between them is made and results are given in this paper.

Hariri, H.; Bernard, Y.; Razek, A.

2014-02-01

342

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

343

Effect of Purging Gas on Wetting Behavior of Sn-3.5Ag Lead-Free Solder on Nickel-Coated Aluminum Substrate  

NASA Astrophysics Data System (ADS)

The wetting characteristics of Sn-3.5Ag lead-free solder alloy on nickel-coated aluminum substrates in air (ambient), nitrogen, and argon atmospheres were investigated. The contact angles for the solder alloy obtained under air and argon atmospheres were in the range of 36-38. With nitrogen atmosphere the contact angle was found to be significantly lower at about 26. Solder solidifying in air exhibited needle-shaped tin-rich dendrites surrounded by a eutectic matrix. The amount of tin dendrites decreased in argon atmosphere. However, the morphology of tin dendrites transformed from needle-shaped to nearly non-dendritic shape as the soldering atmosphere was changed from air to nitrogen. The interfacial microstructures revealed the presence of Ni3Sn and Ni3Sn4 IMCs at the interface. The enhanced wettability observed under nitrogen atmosphere is attributed to the higher thermal conductivity of nitrogen gas and the formation of higher amount of Ni3Sn IMCs at the interface compared to air and argon atmospheres.

Prabhu, K. N.; Varun, M.; Satyanarayan

2013-03-01

344

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

345

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

346

Nonlinear piezoelectric resonance: A theoretically rigorous approach to constant I-V measurements  

NASA Astrophysics Data System (ADS)

Methods for piezoelectric characterization include the standard resonance test. At higher powers, however, the material's inherent nonlinearity acts to significantly affect the expected resonance response. High-power resonance methods have previously been developed to describe piezoelectric nonlinearity. In this article we specify and describe the approximations adopted in the current theory and propose a more rigorous theory derived from fundamental principles. We first use thermodynamics to derive the form of the constitutive equations. In particular, we propose that the envelope rather than instantaneous values of stress, strain, and electric field must appear in these equations to yield a type of nonlinearity which, nonetheless, yields a sinusoidal current for sinusoid applied voltage. An alternative approach is set out describing the highly nonlinear experimental data by fitting just one adjustable material parameter to the entire impedance response measured around resonance. Theoretical descriptions for conventional constant-voltage and modified constant-current excitation are developed and compared with experiments for soft and hard compositions of a piezoelectric ceramic (PZT-5H and PZT-4D). The theory is able to match whole families of constant-voltage and constant-current curves with only one adjustable parameter. These models may be used to characterize the high-power properties of piezoelectric materials.

Blackburn, John F.; Cain, Markys G.

2006-12-01

347

Piezoelectric and Semiconducting Coupled Nanogenerators  

NASA Technical Reports Server (NTRS)

An electrical generator includes a substrate, a semiconductor piezoelectric structure having a first end and an opposite second end disposed adjacent to the substrate, a first conductive contact and a second conductive contact. The structure bends when a force is applied adjacent to the first end, thereby causing an electrical potential difference to exist between a first side and a second side of the structure. The first conductive contact is in electrical communication with the first end and includes a material that creates a Schottky barrier between a portion of the first end of the structure and the first conductive contact. The first conductive contact is also disposed relative to the structure in a position so that the Schottky barrier is forward biased when the structure is deformed, thereby allowing current to flow from the first conductive contact into the first end.

Wang, Zhong L. (Inventor); Song, Jinhui (Inventor); Wang, Xudong (Inventor)

2012-01-01

348

Variational Asymptotic Micromechanics Modeling of Heterogeneous Piezoelectric  

E-print Network

Variational Asymptotic Micromechanics Modeling of Heterogeneous Piezoelectric Materials Tian Tang-4130, USA Abstract In this paper, a new micromechanics model is developed to predict the effective method for unit cell homogenization (VAMUCH), a recently developed micromechanics modeling technique

Yu, Wenbin

349

INTEGRATED MICROBIOREACTOR WITH PIEZOELECTRIC TRANSDUCER ARRAY FOR  

E-print Network

INTEGRATED MICROBIOREACTOR WITH PIEZOELECTRIC TRANSDUCER ARRAY FOR CELLULAR DIAGNOSTICS Yu ABSTRACT This paper reports a perfusion microbioreactor that can be integrated with a pie- zoelectric verifications of the microbioreactor are discussed. KEYWORDS: Microbioreactor, Cell culture INTRODUCTION

Tang, William C

350

Piezoelectric MEMS resonator characterization and filter design  

E-print Network

This thesis presents modeling and first measurements of a new piezoelectric MEMS resonator developed at Draper Laboratory. In addition, some simple filter designs incorporating the resonator with predicted performance ...

Kang, Joung-Mo, 1978-

2004-01-01

351

NMR and optical studies of piezoelectric polymers  

SciTech Connect

Progress is reported in several areas dealing with piezoelectric (electroactive) polymers (mostly vinylidene fluoride, trifluoroethylene, copolymers, PVF[sub 2]) and liquid crystals. Optical studies, neutron scattering, NMR, thermal, theory and modeling were done.

Schmidt, V.H.; Tuthill, G.F.

1993-01-01

352

Harvesting Raindrop Energy with Piezoelectrics: a Review  

NASA Astrophysics Data System (ADS)

Harvesting vibration energy from piezoelectric material impacted by raindrops has proved to be a promising approach for future applications. A piezoelectric harvester has interesting advantages such as simple structure, easy fabrication, reduced number of components, and direct conversion of vibrations to electrical charge. Extensive research has been carried out and is still underway to explore this technique for practical applications. This review provides a comprehensive picture of global research and development of raindrop energy harvesting using piezoelectric material to enable researchers to determine the direction of further investigation. The work published so far in this area is reviewed and summarized with relevant suggestions for future work. In addition, a brief experiment was carried out to investigate the suitable piezoelectric structure for raindrop energy harvesting. Results showed that the bridge structure generated a higher voltage compared with the cantilever structure.

Wong, Chin-Hong; Dahari, Zuraini; Abd Manaf, Asrulnizam; Miskam, Muhammad Azman

2015-01-01

353

Thermally Stable Piezoelectric and Pyroelectric Polymers  

NASA Technical Reports Server (NTRS)

A class of thermally stable piezoelectric and pyroelectric polymers, and an improved method of making them, have been invented. These polymers can be used as substrates for a wide variety of electromechanical transducers, sensors, and actuators.

Simpson, Joycelyn O.; St. Clair, Terry L.

2006-01-01

354

Piezoelectric nanoparticle-polymer composite foams.  

PubMed

Piezoelectric polymer composite foams are synthesized using different sugar-templating strategies. By incorporating sugar grains directly into polydimethylsiloxane mixtures containing barium titanate nanoparticles and carbon nanotubes, followed by removal of the sugar after polymer curing, highly compliant materials with excellent piezoelectric properties can be fabricated. Porosities and elasticity are tuned by simply adjusting the sugar/polymer mass ratio which gave an upper bound on the porosity of 73% and a lower bound on the elastic coefficient of 32 kPa. The electrical performance of the foams showed a direct relationship between porosity and the piezoelectric outputs, giving piezoelectric coefficient values of ?112 pC/N and a power output of ?18 mW/cm3 under a load of 10 N for the highest porosity samples. These novel materials should find exciting use in a variety of applications including energy scavenging platforms, biosensors, and acoustic actuators. PMID:25353687

McCall, William R; Kim, Kanguk; Heath, Cory; La Pierre, Gina; Sirbuly, Donald J

2014-11-26

355

Studying insect motion with piezoelectric sensors  

NASA Astrophysics Data System (ADS)

Piezoelectric materials have been widely used in applications such as transducers, acoustic components, as well as motion, pressure and airborne sensors. Because of the material's biocompatibility and flexibility, we have been able to apply small piezoelectric sensors, made of PVDF, to cockroaches. We built a laboratory test system to study the piezoelectric properties of a bending sensor. The tested motion was compared with that of the sensor attached to a cockroach. Surface characterization and finite element analysis revealed the effects of microstructure on piezoelectric response. The sensor attachment enables us to monitor the insects' locomotion and study their behaviors. The applications of engineering materials to insects opens the door to innovating approaches to integrating biological, mechanical and electrical systems.

Mika, Bartosz; Lee, Hyungoo; Gonzlez, Jorge M.; Vinson, S. Bradleigh; Liang, Hong

2007-04-01

356

A nanoscale piezoelectric transformer for low-voltage transistors.  

PubMed

A novel piezoelectric voltage transformer for low-voltage transistors is proposed. Placing a piezoelectric transformer on the gate of a field-effect transistor results in the piezoelectric transformer field-effect transistor that can switch at significantly lower voltages than a conventional transistor. The piezoelectric transformer operates by using one piezoelectric to squeeze another piezoelectric to generate a higher output voltage than the input voltage. Multiple piezoelectrics can be used to squeeze a single piezoelectric layer to generate an even higher voltage amplification. Coupled electrical and mechanical modeling in COMSOL predicts a 12.5 voltage amplification for a six-layer piezoelectric transformer. This would lead to more than a 150 reduction in the power needed for communications. PMID:25343519

Agarwal, Sapan; Yablonovitch, Eli

2014-11-12

357

Development of a Templated Grain Growth System for Texturing Piezoelectric Ceramics  

E-print Network

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

Azad, Abdul-Majeed

358

SLIDING MODE CONTROL OF PIEZOELECTRIC VALVE REGULATED PNEUMATIC ACTUATOR FOR MRI-COMPATIBLE ROBOTIC INTERVENTION  

E-print Network

SLIDING MODE CONTROL OF PIEZOELECTRIC VALVE REGULATED PNEUMATIC ACTUATOR FOR MRI-COMPATIBLE ROBOTIC regulated by piezoelectric valve for image guided robotic intervention. After comparing pneumatic, hydraulic and piezoelectric MRI compatible actuation technologies, we present a piezoelectric valve regulated pneumatic

Camesano, Terri

359

Constitutive modeling of piezoelectric polymer composites  

Microsoft Academic Search

A new modeling approach is proposed for predicting the bulk electromechanical properties of piezoelectric composites. The proposed model offers the same level of convenience as the well-known MoriTanaka method. The electromechanical properties of four piezoelectric polymer composite materials are predicted with the proposed, MoriTanaka, Self-consistent methods, and detailed finite element analyses are conducted over full ranges of reinforcement volume fractions.

Gregory M. Odegard

2004-01-01

360

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

361

Active piezo-electric damping composites  

Microsoft Academic Search

Active piezo-electric damping composites (APDC) consisting of piezoelectric rods, which are obliquely embedded across the thickness of a viscoelastic damping matrix, are presented. In this configuration, activation of the piezo-rods simultaneously enhances both the shear and compression damping characteristics of the composite. With such active\\/passive capabilities, the APDC presents a viable and effective means for controlling structural vibration and noise.

A. Baz; A. Tempia

1998-01-01

362

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

363

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

364

Passive modal damping with piezoelectric shunts  

SciTech Connect

The use of piezoelectric materials in conjunction with passive inductance-resistance-capacitance (RLC) circuits to dampen specific vibration modes is explored. The piezoelectric materials convert mechanical energy to electrical energy, which is then dissipated in the RLC circuit through joule heating. An impulse is applied to a simple cantilevered beam and by varying the inductance and resistance values, the natural oscillation frequency fcir the RLC circuit is tuned to dampen the first mode of vibration.

Granier, J. J. (John J.); Haundhausen, R. J. (R. Jason); Gaytan, G. E. (Gabriel E.)

2001-01-01

365

Piezoelectric micro-power generation interface circuits  

Microsoft Academic Search

New power conversion circuits to interface to a piezoelectric micro-power generator have been fabricated and tested. Circuit designs and measurement results are presented for a half-wave synchronous rectifier with voltage doubler, a full-wave synchronous rectifier and a passive full-wave rectifier circuit connected to the piezoelectric micro-power generator. The measured power efficiency of the synchronous rectifier and voltage doubler circuit fabricated

Triet T. Le; Jifeng Han; Annette von Jouanne; Kartikeya Mayaram; Terri S. Fiez

2006-01-01

366

The piezoelectric sorption technique: a practical method  

E-print Network

THE PIEZOELECTRIC SORPTION TECHNIQUE, A PRACTICAL METHOD A Thesis by EUGENE CHARLES FLIPSE Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE August 1983...) D. Holland (Head of Department) August 1983 ABSTRACT The Piezoelectric Sorption Technique, A Practical Method. (August 1983) Eugene Charles Flipse, B. A. , Virginia Polytechnic Institute and State University Chairman of Advisory Committee: Dr...

Flipse, Eugene Charles

1983-01-01

367

Dielectric loss against piezoelectric power harvesting  

NASA Astrophysics Data System (ADS)

Piezoelectricity is one of the most popular electromechanical transduction mechanisms for constructing kinetic energy harvesting systems. When a standard energy harvesting (SEH) interface circuit, i.e., bridge rectifier plus filter capacitor, is utilized for collecting piezoelectric power, the previous literature showed that the power conversion can be well predicted without much consideration for the effect of dielectric loss. Yet, as the conversion power gets higher by adopting power-boosting interface circuits, such as synchronized switch harvesting on inductor (SSHI), the neglect of dielectric loss might give rise to deviation in harvested power estimation. Given the continuous progress on power-boosting interface circuits, the role of dielectric loss in practical piezoelectric energy harvesting (PEH) systems should receive attention with better evaluation. Based on the integrated equivalent impedance network model, this fast track communication provides a comprehensive study on the susceptibility of harvested power in PEH systems under different conditions. It shows that, dielectric loss always counteracts piezoelectric power harvesting by causing charge leakage across piezoelectric capacitance. In particular, taking corresponding ideal lossless cases as references, the counteractive effect might be aggravated under one of the five conditions: larger dielectric loss tangent, lower vibration frequency, further away from resonance, weaker electromechanical coupling, or using power-boosting interface circuit. These relationships are valuable for the study of PEH systems, as they not only help explain the role of dielectric loss in piezoelectric power harvesting, but also add complementary insights for material, structure, excitation, and circuit considerations towards holistic evaluation and design for practical PEH systems.

Liang, Junrui; Shu-Hung Chung, Henry; Liao, Wei-Hsin

2014-09-01

368

Nucleation and Growth of Cu-Al Intermetallics in Al-Modified Sn-Cu and Sn-Ag-Cu Lead-Free Solder Alloys  

NASA Astrophysics Data System (ADS)

Lead-free solder alloys Sn-Cu (SC) and Sn-Ag-Cu (SAC) are widely used by the microelectronics industry, but enhanced control of the microstructure is needed to improve solder performance. For such control, nucleation and stability of Cu-Al intermetallic compound (IMC) solidification catalysts were investigated by variation of the Cu (0.7-3.0 wt.%) and Al (0.0-0.4 wt.%) content of SC + Al and SAC + Al alloys, and of SAC + Al ball-grid array (BGA) solder joints. All of the Al-modified alloys produced Cu-Al IMC particles with different morphologies and phases (occasionally non-equilibrium phases). A trend of increasing Cu-Al IMC volume fraction with increasing Al content was established. Because of solidification of non-equilibrium phases in wire alloy structures, differential scanning calorimetry (DSC) experiments revealed delayed, non-equilibrium melting at high temperatures related to quenched-in Cu-Al phases; a final liquidus of 960-1200C was recorded. During cooling from 1200C, the DSC samples had the solidification behavior expected from thermodynamic equilibrium calculations. Solidification of the ternary alloys commenced with formation of ternary ? and Cu-Al ? phases at 450-550C; this was followed by ?-Sn, and, finally, Cu6Sn5 and Cu-Al ?1. Because of the presence of the retained, high-temperature phases in the alloys, particle size and volume fraction of the room temperature Cu-Al IMC phases were observed to increase when the alloy casting temperature was reduced from 1200C to 800C, even though both temperatures are above the calculated liquidus temperature of the alloys. Preliminary electron backscatter diffraction results seemed to show Sn grain refinement in the SAC + Al BGA alloy.

Reeve, Kathlene N.; Anderson, Iver E.; Handwerker, Carol A.

2015-03-01

369

A Study on the Physical Properties and Interfacial Reactions with Cu Substrate of Rapidly Solidified Sn-3.5Ag Lead-Free Solder  

NASA Astrophysics Data System (ADS)

A rapidly solidified Sn-3.5Ag eutectic alloy produced by the melt-spinning technique was used as a sample in this research to investigate the microstructure, thermal properties, solder wettability, and inhibitory effect of Ag3Sn on Cu6Sn5 intermetallic compound (IMC). In addition, an as-cast Sn-3.5Ag solder was prepared as a reference. Rapidly solidified and as-cast Sn-3.5Ag alloys of the same size were soldered at 250C for 1 s to observe their instant melting characteristics and for 3 s with different cooling methods to study the inhibitory effect of Ag3Sn on Cu6Sn5 IMC. Experimental techniques such as scanning electron microscopy, differential scanning calorimetry, and energy-dispersive spectrometry were used to observe and analyze the results of the study. It was found that rapidly solidified Sn-3.5Ag solder has more uniform microstructure, better wettability, and higher melting rate as compared with the as-cast material; Ag3Sn nanoparticles that formed in the rapidly solidified Sn-3.5Ag solder inhibited the growth of Cu6Sn5 IMC during aging significantly much strongly than in the as-cast material because their number in the rapidly solidified Sn-3.5Ag solder was greater than in the as-cast material with the same soldering process before aging. Among the various alternative lead-free solders, this study focused on comparison between rapidly solidified and as-cast solder alloys, with the former being observed to have better properties.

Ma, Hai-Tao; Wang, Jie; Qu, Lin; Zhao, Ning; Kunwar, A.

2013-08-01

370

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

371

Precise Measurement of Losses in Piezoelectric Transducer and Its Application to Evaluation of Piezoelectric Transformer Efficiency  

Microsoft Academic Search

Mechanical and dielectric losses were measured by the measurement method proposed in this paper in a piezoelectric transducer with input and output terminals. These losses must be considered in designing piezoelectric transformers used as power sources. In the method proposed here, the losses can be obtained using the experimental results of resonance angular frequency, quality factor and the resistive component

Tsutomu Endow; Seiji Hirose; Tomoyuki Kanno

2004-01-01

372

Dielectrophoretically structured piezoelectric composites with high aspect ratio piezoelectric particles inclusions  

NASA Astrophysics Data System (ADS)

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

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

2012-06-01

373

Effect of interfacial strength between Cu6Sn5 and Cu3Sn intermetallics on the brittle fracture failure of lead-free solder joints with OSP pad finish  

Microsoft Academic Search

The brittle failure mechanism of solder joints has gained more and more attention due to the introduction of lead-free solders and also the extensive use of different kinds of portable electronic products. The excessive growth of the IMC is blamed to increase the propensity of the brittle failure. Typically the thickness of the IMC layer is used to indicate the

Chaoran Yang; Fubin Song; S. W. Ricky Lee

2011-01-01

374

Model of a Piezoelectric Transducer  

NASA Technical Reports Server (NTRS)

It's difficult to control liquid and gas in propellant tanks in zero gravity. A possible a design would utilize acoustic liquid manipulation (ALM) technology which uses ultrasonic beams conducted through a liquid and solid media, to push gas bubbles in the liquid to desirable locations. We can propel and control the bubble with acoustic radiation pressure by aiming the acoustic waves on the bubble s surface. This allows us to design a so called smart tank in which the ALM devices transfer the gas to the outer wall of the tank and isolating the liquid in the center. Because the heat transfer rate of a gas is lower of that of the liquid it would substantially decrease boil off and provide of for a longer storage life. The ALM beam is composed of little wavelets which are individual waves that constructively interfere with each other to produce a single, combined acoustic wave front. This is accomplished by using a set of synchronized ultrasound transducers arranged in an array. A slight phase offset of these elements allows us to focus and steer the beam. The device that we are using to produce the acoustic beam is called the piezoelectric transducer. This device converts electrical energy to mechanical energy, which appears in the form of acoustic energy. Therefore the behavior of the device is dependent on both the mechanical characteristics, such as its density, cross-sectional area, and its electrical characteristics, such as, electric flux permittivity and coupling factor. These devices can also be set up in a number of modes which are determined by the way the piezoelectric device is arranged, and the shape of the transducer. For this application we are using the longitudinal or thickness mode for our operation. The transducer also vibrates in the lateral mode, and one of the goals of my project is to decrease the amount of energy lost to the lateral mode. To model the behavior of the transducers I will be using Pspice, electric circuit modeling tool, to determine the transducer's electrical characteristics at the frequency of interest. This will also help me determine the characteristics of an impedance matching network to operate the transducer at its optimum efficiency. For this I will use ABMs (analog behavioral modeling) to model dependent current and voltage sources that represent the transducer. I have also been working on the Labview control software for the phased array used to control the bubbles, and will begin testing on that before the end of my internship.

Goodenow, Debra

2004-01-01

375

Piezoelectric microcantilever serum protein detector  

NASA Astrophysics Data System (ADS)

The development of a serum protein detector will provide opportunities for better screening of at-risk cancer patients, tighter surveillance of disease recurrence and better monitoring of treatment. An integrated system that can process clinical samples for a number of different types of biomarkers would be a useful tool in the early detection of cancer. Also, screening biomarkers such as antibodies in serum would provide clinicians with information regarding the patient's response to treatment. Therefore, the goal of this study is to develop a sensor which can be used for rapid, all-electrical, real-time, label-fee, in-situ, specific quantification of cancer markers, e.g., human epidermal receptor 2 (Her2) or antibodies, in serum. To achieve this end, piezoelectric microcantilever sensors (PEMS) were constructed using an 8 mum thick lead magnesium niobate-lead titanate (PMN-PT) freestanding film as the piezoelectric layer. The desired limit of detection is on the order of pg/mL. In order to achieve this goal the higher frequency lateral extension modes were used. Also, as the driving and sensing of the PEMS is electrical, the PEMS must be insulated in a manner that allows it to function in aqueous solutions. The insulation layer must also be compatible with standardized bioconjugation techniques. Finally, detection of both cancer antigens and antibodies in serum was carried out, and the results were compared to a standard commercialized protocol. PEMS have demonstrated the capability of detecting Her2 at a concentration of 5 pg/mL in diluted human serum (1:40) in less than 1 hour. The approach can be easily translated into the clinical setting because the sensitivity is more than sufficient for monitoring prognosis of breast cancer patients. In addition to Her2 detection, antibodies in serum were assayed in order to demonstrate the feasibility of monitoring the immune response for antibody-dependent cellular cytotoxicity (ADCC) in patients on antibody therapies such as Herceptin and Cetuximab. The PEMS displayed a limit of detection of 100 fg/mL, which was 100 times lower than the current methods of protein detection in serum, such as ELISA. Furthermore, the sensitivity of the PEMS device allows it to be capable of determining the dissociation constant, K d, of selective receptors such as antibodies. Using the dose response trials of Her2, Kd has been deduced for H3 scFv, and Herceptin, a commercial antibody specific for Her2.

Capobianco, Joseph A.

376

Force control in piezoelectric microactuators using self scheduled H technique  

E-print Network

Force control in piezoelectric microactuators using self scheduled H technique Micky Rakotondrabe-scheduled controller, H, force, piezoactuators, micromanipulation and microasembly 1. INTRODUCTION Piezoelectric to control the manipulation force. In fact, the force control allows keeping the manipulated object inside

Boyer, Edmond

377

Effective Properties of Carbon Nanotube and Piezoelectric Fiber  

E-print Network

have been determined by a micromechanical analysis. Values of the effective piezoelectric coefficient e of an epoxy reinforced with a mono- lithic piezoelectric material PZT , provide a wide range of effec- tive

Beex, A. A. "Louis"

378

Narcotics detection using piezoelectric ringing  

NASA Astrophysics Data System (ADS)

Piezo-electric ringing (PER) has been demonstrated to be an effective means of scanning cargo for the presence of hidden narcotics. The PER signal is characteristic of certain types of crystallized material, such as cocaine hydrochloride. However, the PER signal cannot be used to conclusively identify all types of narcotic material, as the signal is not unique. For the purposes of cargo scanning, the PER technique is therefore most effective when used in combination with quadrupole resonance analysis (QRA). PER shares the same methodology as QRA technology, and can therefore be very easily and inexpensively integrated into existing QRA detectors. PER can be used as a pre-scanning technique before the QRA scan is applied and, because the PER scan is of a very short duration, can effectively offset some of the throughput limitations of standard QRA narcotics detectors. Following is a discussion of a PER detector developed by Quantum Manetics under contract to United States Customs. Design philosophy and performance are discussed, supported by results from recent tests conducted by the U.S. Drug Enforcement Agency and U.S. Customs.

Rayner, Timothy J.; Magnuson, Erik E.; West, Rebecca; Lyndquist, R.

1997-02-01

379

Energy Harvesting From Low Frequency Applications Using Piezoelectric Materials  

SciTech Connect

This paper reviewed the state of research on piezoelectric energy harvesters. Various types of harvester configurations, piezoelectric materials, and techniques used to improve the mechanical-to-electrical energy conversion efficiency were discussed. Most of the piezoelectric energy harvesters studied today have focused on scavenging mechanical energy from vibration sources due to their abundance in both natural and industrial environments. Cantilever beams have been the most studied structure for piezoelectric energy harvester to date because of the high responsiveness to small vibrations.

Li, Huidong; Tian, Chuan; Deng, Zhiqun

2014-11-06

380

Piezoelectric biosensor with a ladder polymer substrate coating  

DOEpatents

A piezoelectric biosensor substrate useful for immobilizing biomolecules in an oriented manner on the surface of a piezoelectric sensor has a ladder polymer of polyacrylonitrile. To make the substrate, a solution of an organic polymer, preferably polyacrylonitrile, is applied to the surface of a piezoelectric sensor. The organic polymer is modifying by heating the polymer in a controlled fashion in air such that a ladder polymer is produced which, in turn, forms the attachment point for the biomolecules comprising the piezoelectric biosensor.

Renschler, Clifford L. (Tijeras, NM); White, Christine A. (Albuquerque, NM); Carter, Robert M. (New Orleans, LA)

1998-01-01

381

Piezoelectricity and Ferroelectricity in one dimensional nanowires  

NASA Astrophysics Data System (ADS)

Two recent studies, one by Mele and Krl on the theoretical study of the polarization and piezoelectricity of BN nanotube and another by Yun et al. on the experimental study of the synthesis and the ferroelectric property of BaTiO3 single crystalline nanowire, showed exciting results for such piezoelectric/ferroelectric nanomaterials being used for studying low dimensional piezoelectricity and ferroelectricity at the nanoscale. These two nanomaterials represent two unique material nanosystems. BN nanotube is layered and uniquely tubular in structure and has chiral symmetry variations; and BaTiO3 nanowire is a crystalline and one dimensional solid. In this study, we report our recent results on the synthesis of BaTiO3 nanowires having diameters of as small as 6 nm, and the piezoelectric characterization of such nanowires; we also present our systematic study of the mechanics and the piezoelectric property of individual BN nanotubes, using our recently developed advanced nanomanipulation tools integrated with various microscopes.

Wang, Zhaoyu; Suryavanshi, Abhijit; Wen, Jianguo; Yu, Min-Feng

2004-03-01

382

High-Fidelity Piezoelectric Audio Device  

NASA Technical Reports Server (NTRS)

ModalMax is a very innovative means of harnessing the vibration of a piezoelectric actuator to produce an energy efficient low-profile device with high-bandwidth high-fidelity audio response. The piezoelectric audio device outperforms many commercially available speakers made using speaker cones. The piezoelectric device weighs substantially less (4 g) than the speaker cones which use magnets (10 g). ModalMax devices have extreme fabrication simplicity. The entire audio device is fabricated by lamination. The simplicity of the design lends itself to lower cost. The piezoelectric audio device can be used without its acoustic chambers and thereby resulting in a very low thickness of 0.023 in. (0.58 mm). The piezoelectric audio device can be completely encapsulated, which makes it very attractive for use in wet environments. Encapsulation does not significantly alter the audio response. Its small size (see Figure 1) is applicable to many consumer electronic products, such as pagers, portable radios, headphones, laptop computers, computer monitors, toys, and electronic games. The audio device can also be used in automobile or aircraft sound systems.

Woodward, Stanley E.; Fox, Robert L.; Bryant, Robert G.

2003-01-01

383

Ultrasonic wave propagation in multilayered piezoelectric substrates  

SciTech Connect

Due to the increasing demand for higher operating frequency, lower attenuation, and stronger piezoelectricity, use of the layered structure has become necessary. Theoretical studies are carried out for ultrasonic waves propagating in the multilayered piezoelectric substrates. Each layer processes up to as low as monoclinic symmetry with various thickness and orientation. A plane acoustic wave is assumed to be incident, at varied frequency and incidence angle, from a fluid upon a multilayered substrate. Simple analytical expressions for the reflection and transmission coefficients are derived from which all propagation characteristics are identified. Such expressions contain, as a by-product, the secular equation for the propagation of free harmonic waves on the multilayered piezoelectric substrates. Solutions are obtained for the individual layers which relate the field variables at the upper layer surfaces. The response of the total system proceeds by satisfying appropriate interfacial conditions across the layers. Based on the boundary conditions, two cases, {open_quotes}shorted{close_quotes} and {open_quotes}free{close_quotes}, are derived from which a so-called piezoelectric coupling factor is calculated to show the piezoelectric efficiency. Our results are rather general and show that the phase velocity is a function of frequency, layer thickness, and orientation.

Chien, H.T.; Sheen, S.H.; Raptis, A.C.

1994-04-11

384

Love wave propagation in functionally graded piezoelectric material layer  

Microsoft Academic Search

An exact approach is used to investigate Love waves in functionally graded piezoelectric material (FGPM) layer bonded to a semi-infinite homogeneous solid. The piezoelectric material is polarized in z-axis direction and the material properties change gradually with the thickness of the layer. We here assume that all material properties of the piezoelectric layer have the same exponential function distribution along

Jianke Du; Xiaoying Jin; Ji Wang; Kai Xian

2007-01-01

385

Series-parallel impedance structure for piezoelectric vibration damping  

Microsoft Academic Search

This paper introduces a passive piezoelectric shunt controller, for damping multiple modes of a flexible structure using one piezoelectric transducer. The series-parallel impedance structure has a number of advantages over to previous techniques; it is simpler to implement, requires less passive elements and contains smaller inductors values. The vibration control strategy is validated through experimental work on a piezoelectric laminated

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

2002-01-01

386

Design and Performance of Miniaturized Piezoelectric Step-Down Transformer  

Microsoft Academic Search

Piezoelectric transformers are expected to be small, thin and highly efficient, and which are attractive as a transformer with high power density for step down voltage. For these reasons, we have attempted to develop a step-down piezoelectric transformer for the miniaturized adaptor. we propose a piezoelectric transformer, operating in thickness extensional vibration mode for step-down voltage. This transformer consists of

Kee-Joe Lim; Seong-Hwa Kang; Hyun-Hoo Kim; Jong-Sub Lee; Su-Hyun Jeong

2004-01-01

387

Electromechanical Properties of Piezoelectric Integrated Structures on Porous Substrates  

Microsoft Academic Search

The fabrication of piezoelectric transducers for high resolution medical imaging applications requires a backing material to damp the piezoelectric resonance, resulting in a shorter time response, i.e. improved resolution, but lower sensitivity. Thus, the choice of such a substrate must be made according to its acoustical properties, namely the ratio of acoustic impedance of the backing material and the piezoelectric

P. Marechal; F. Levassort; J. Holc; D. Ku?er; M. Kosec; G. Feuillard; M. Lethiecq

2008-01-01

388

Research on a micropump structure with piezoelectric actuator  

Microsoft Academic Search

Based on the working principle of piezoelectricity, an electromechanical-coupled mechanics model is established for the circle-flake microactuator. By using the elastic thin plate bending theory with small deflection, some differential equations for elastic curved surface in circular piezoelectric composite laminates are derived and a kind of analysis and design method is presented that piezoelectric patch's radial strain induced by inverse

WeiDong Wang; JianYuan Jia; ZhiWu Li

2005-01-01

389

Dynamic response of a piezoelectric rod with thermal relaxation  

Microsoft Academic Search

Based on the Lord and Shulman generalized thermo-elastic theory with one relaxation time, the dynamic thermal and elastic responses of a piezoelectric rod fixed at both ends and subjected to a moving heat source are investigated. The generalized piezoelectricthermoelastic coupled governing equations for piezoelectric rod are formulated. By means of Laplace transformation and numerical Laplace inversion the governing equations are

Tianhu He; Li Cao; Shirong Li

2007-01-01

390

Effect of piezoelectric rod orientation on optimum sensitivity  

Microsoft Academic Search

Piezoelectric composites are being developed for use as active materials in isolation mounts. The ability to sense and respond to both longitudinal and shear waves is required. Composites have been fabricated with piezoelectric rods at different angles with respect to the surface. The response of the piezoelectric rods to a sharp impulse on the 1 - 3 composite plate increases

H. D. Batha

1993-01-01

391

CHARACTERIZATION OF PIEZOELECTRIC ACTUATORS FOR FLOW CONTROL OVER A WING  

E-print Network

CHARACTERIZATION OF PIEZOELECTRIC ACTUATORS FOR FLOW CONTROL OVER A WING K. Mossi, R. Bryant, require real estate, and add complexity to an airplane making these options impractical. Piezoelectric piezoelectric actuators as part of complete mechanisms, machines, or devices are rare. One of the main reason

Mossi, Karla

392

Piezoelectric Properties of Non-Polar Block Copolymers  

SciTech Connect

Piezoelectric properties in non-polar block copolymers are a novelty in the field of electroactive polymers. The piezoelectric susceptibility of poly(styrene-b-isoprene) block copolymer lamellae is found to be up to an order of magnitude higher when compared to classic piezoelectric materials. The electroactive response increases with temperature and is found to be strongest in the disordered phase.

Pester, Christian [RWTH Aachen University; Ruppel, Markus A [ORNL; Schoberth, Heiko [University of Bayreuth; Schmidt, K. [Universitat Bayreuth; Liedel, Clemens [RWTH Aachen University; Van Rijn, Patrick [RWTH Aachen University; Littrell, Ken [ORNL; Schindler, Kerstin [RWTH Aachen University; Hiltl, Stephanie [RWTH Aachen University; Czubak, Thomas [RWTH Aachen University; Mays, Jimmy [ORNL; Urban, Volker S [ORNL; Boker, Alexander [RWTH Aachen University

2011-01-01

393

Characterization of a Piezoelectric Buzzer Using a Michelson Interferometer  

ERIC Educational Resources Information Center

A piezoelectric material generates an electric potential across its surface when subjected to mechanical stress; conversely, the inverse piezoelectric effect describes the expansion or contraction of the material when subjected to some applied voltage. Piezoelectric materials are used in devices such as doorbell buzzers, barbeque igniters, and

Lloyd, S.; Paetkau, M.

2010-01-01

394

Low-power piezoelectric micro-machined valve  

NASA Technical Reports Server (NTRS)

A piezoelectric microvalve employs a valve element formed of hermetically sealed and opposed plates flexed together by a cross axis piezoelectric element. Large flow modulation with small piezoelectric actuator displacement is obtained by perimeter augmentation of the valve seat which dramatically increases the change in valve flow area for small deflections.

Gianchandani, Yogesh B. (Inventor); Nellis, Gregory Francis (Inventor); Klein, Sanford A. (Inventor); Park, John Moon (Inventor); Evans, Allan Thomas (Inventor); Taylor, Ryan (Inventor); Brosten, Tyler R. (Inventor)

2010-01-01

395

Pulsed DC magnetron sputtered piezoelectric thin film aluminum nitride Technology and piezoelectric properties  

SciTech Connect

Pulsed DC magnetron sputtered aluminum nitride (AlN) thin films are prepared on several seed layers and at different sputtering conditions. The piezoelectric c-axis (002) orientation of the AlN is analyzed with X-ray diffraction method. The transverse piezoelectric coefficient d{sub 31} is determined with a Laser-Doppler-Vibrometer at cantilevers and membranes by analytical calculations and finite element method. Additionally, thin film AlN on bulk silicon is used to characterize the longitudinal piezoelectric charge coefficient d{sub 33}.

Stoeckel, C., E-mail: chris.stoeckel@zfm.tu-chemnitz.de; Kaufmann, C.; Hahn, R.; Schulze, R. [Center for Microtechnologies, Chemnitz University of Technology, Chemnitz 09126 (Germany); Billep, D. [Fraunhofer Institute for Electronic Nano Systems (ENAS), Chemnitz 09126 (Germany); Gessner, T. [Center for Microtechnologies, Chemnitz University of Technology, Chemnitz 09126 (Germany); Fraunhofer Institute for Electronic Nano Systems (ENAS), Chemnitz 09126 (Germany)

2014-07-21

396

Magnetocaloric piezoelectric composites for energy harvesting  

NASA Astrophysics Data System (ADS)

Magnetocaloric alloy, Gd5Si2Ge2, was developed into a composite with the poly(vinylidene fluoride) (PVDF) piezoelectric polymer. This multifunctional material possesses unique properties that are suitable for energy conversion and harvesting. Experimental approaches include using an arc melting technique to synthesize the Gd5Si2Ge2 (GSG) alloy and the spinning casting method to fabricate the composite. The materials were characterized using various techniques at different length scales. These include atomic force microscopy (AFM), optical microscopy, scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS), x-ray diffraction (XRD), and x-ray photoelectron spectroscopy (XPS). The results indicated that the phase transformation of the magnetocaloric material close to its Curie temperature induced a significant increase in power generation in the piezoelectric polymer. The power output of a laminated structure was 1.1 mW, more than 200 thousand times higher than the piezoelectric materials alone (5.1 nW).

Cleveland, Michael; Liang, Hong

2012-04-01

397

Ciliae-based actuator with piezoelectric excitation  

NASA Astrophysics Data System (ADS)

Small actuators based on the inverse piezoelectric effect are successfully deployed in commercial applications. Usually, ultrasonic motors are used. Based on resonance effects these motors provide a pronounced nonlinearity at low speeds and thus put high demands on the control algorithm. In contrast, piezoelectric stepping motors are mechanically complex and provide only low speeds. The contribution at hand describes a proposed design for a new piezoelectric motor based on cilia friction that can be manufactured at low costs. The cilia are made from uniaxial carbon-fibre reinforced plastics. The derived CFRP-brushes are pressed perpendicularly to the rotor surface to produce force or torque. First experiments prove the feasibility of the concept. A net pushing force of 500 mN is achieved.

Pott, Peter P.; Carrasco, Alvaro; Schlaak, Helmut F.

2012-06-01

398

Piezoelectricity in PANI filled Nylon 11  

NASA Astrophysics Data System (ADS)

The piezoelectric response of pure Nylon 11 and conducting Polyaniline (PANI) filled Nylon 11 is presented. Nylon 11 samples were filled with PANI fillers of two different concentrations (1% and 5% w/w) each. The samples were poled using Corona discharge technique with poling field of 200 kV/cm and 350 kV/cm. The piezoelectric strain constant d 31, stress constant e 31 and electromechanical coupling coefficient k 31 of pure and PANI filled samples were measured up to 100C. The study suggests that the piezoelectric coefficient (d 31) of the PANI filled Nylon 11 shows considerable decline with respect to its individual component. The thermal stability of the PANI filled samples improved and is almost stable at comparatively low temperature than pure Nylon 11.

Pande, S. A.; Kelkar, D. S.; Peshwe, D. R.

2007-07-01

399

Design issues of resonant piezoelectric sensors  

NASA Astrophysics Data System (ADS)

This paper presents some issues governing the design of piezoelectric resonant sensors delivering a frequency output. We focus on BAW resonant sensors. As an application example, we consider the case study of miniature temperature sensors using strip resonators as sensing elements. In addition, we shortly discuss the current trends in the field of micromachined inertial acoustic sensors especially regarding miniaturization. Although currently available sensors of this type mostly rely on low frequency flexural vibrations, strip resonators micro-machined in III-V piezoelectric semi conductors multilayer substrates may take over a significant role for such application in the near future since they could bring the precision level characterizing essentially thickness shear resonators into monolithic sensors systems built upon completely integrated piezoelectric oscillators.

Dulmet, Bernard

2008-03-01

400

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

NASA Astrophysics Data System (ADS)

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

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

2014-12-01

401

Nanogenerator comprising piezoelectric semiconducting nanostructures and Schottky conductive contacts  

NASA Technical Reports Server (NTRS)

A semiconducting device includes a substrate, a piezoelectric wire, a structure, a first electrode and a second electrode. The piezoelectric wire has a first end and an opposite second end and is disposed on the substrate. The structure causes the piezoelectric wire to bend in a predetermined manner between the first end and the second end so that the piezoelectric wire enters a first semiconducting state. The first electrode is coupled to the first end and the second electrode is coupled to the second end so that when the piezoelectric wire is in the first semiconducting state, an electrical characteristic will be exhibited between the first electrode and the second electrode.

Wang, Zhong L. (Inventor); Wang, Xudong (Inventor); Song, Jinhui (Inventor); Zhou, Jun (Inventor); He, Jr-Hau (Inventor)

2011-01-01

402

Investigation of Sn-Zn-Bi solders Part II: wetting measurements on Sn-Zn7Bi solders on copper and on PCBs with lead-free finishes by means of the wetting balance method  

Microsoft Academic Search

Purpose The purpose of this paper is to investigate the influence of Bi additions on the wetting properties of SnZn7Bi alloys (Bi=1 and 3 per cent by mass) on a copper substrate and printed circuit boards (PCBs) with lead-free finishes (SnCu, immersion Sn, Ni\\/Au, organic solderability preservative) in the presence of fluxes. The practical implications of the results is

K. Bukat; J. Sitek; M. Ko?cielski; Z. Moser; W. G?sior; J. Pstru?

2010-01-01

403

VDER 12P0S 2MM VERT GOLD -87831-1220 http://parts.digikey.eom/l/parts/350398-conn-header-12pos-2inm-ver.. ^ Lead free  

E-print Network

VDER 12P0S 2MM VERT GOLD - 87831-1220 http://parts.digikey.eom/l/parts/350398-conn-header-12pos-2inm-ver.. Keywords:: In stock ^ Lead free ^ RoHS Compliant ^: Search/\\gain. Gold Through Hole-1220 CONN HEADER 12P0S 2MM VERT GOLD - 87831-1220 - Connectors, Interconnects Digi-Key Part Number

Kleinfeld, David

404

Rockwell Hardness Measurement of  

E-print Network

960-5 Rockwell Hardness Measurement of Metallic Materials Samuel R. Low NISTrecommended p r a c t i c e g u i d e Special Publication 960-5 #12;i Rockwell Hardness Measurement of Metallic Materials: (202) 512­2250 Mail: Stop SSOP, Washington, DC 20402-0001 #12;N FOREWORD The Rockwell hardness test

Colton, Jonathan S.

405

BOOKSHELF Hard Disk Drive  

E-print Network

- widths ever higher as higher frequency disturbances become relevant. THE BOOK Hard Disk Drive Servo examples. In chapters 25 of Hard Disk Drive Servo Systems it is easy to forget that one is reading a book about disk drive control rather than a book on general control theory. Hard Disk Drive Servo Systems

Benmei, Chen

406

Modeling of a piezoelectric rotary ultrasonic motor  

Microsoft Academic Search

A piezoelectric rotary ultrasonic motor is modeled for the purpose of predicting, a priori, motor performance as a function of design parameters. The Rayleigh-Ritz assumed mode energy method is used to model the distributed piezoceramics and the traveling wave dynamics of the stator. Natural frequencies and modeshapes are obtained for a generally configured motor. Nonlinear normal and tangential interface forces

Nesbitt W. Hagood; Andrew J. McFarland

1995-01-01

407

Porous Piezoelectric CeramicsA Historical Overview  

Microsoft Academic Search

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

Andrey N. Rybyanets

2011-01-01

408

Porous Piezoelectric Ceramics - A historical overview  

Microsoft Academic Search

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

Andrey N. Rybyanets

2010-01-01

409

An Autonomous Piezoelectric Shunt Damping System  

Microsoft Academic Search

Passive shunt damping involves the connection of an electrical shunt network to a structurally attached piezoelec- tric 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

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

410

Piezoelectric Pressure Transducer with Acoustic Absorbing Rod  

Microsoft Academic Search

A piezoelectric pressure transducer has been designed, using readily available, inexpensive materials, which is capable of measuring sidewall pressures over a wide frequency range without serious distortion of the signal due to spurious elastic waves in the sensing element. The rise time is limited primarily by the transit time across the surface of the sensing element. The response of the

K. W. Ragland; R. E. Cullen

1967-01-01

411

Asymptotic modeling of linearly piezoelectric slender rods  

NASA Astrophysics Data System (ADS)

The piezoelectric thin plate modeling already derived by the authors is extended to rod-like structures. Two models corresponding to sensor or actuator behavior are obtained. The conditions of existence of non-local terms in the limit models are discussed. To cite this article: T. Weller, C. Licht, C. R. Mecanique 336 (2008).

Weller, Thibaut; Licht, Christian

2008-07-01

412

Asymptotic modeling of linearly piezoelectric slender rods  

Microsoft Academic Search

The piezoelectric thin plate modeling already derived by the authors is extended to rod-like structures. Two models corresponding to sensor or actuator behavior are obtained. The conditions of existence of non-local terms in the limit models are discussed. To cite this article: T. Weller, C. Licht, C. R. Mecanique 336 (2008).

Thibaut Weller; Christian Licht

2008-01-01

413

Dimensional reduction of a piezoelectric composite rod  

Microsoft Academic Search

In the present paper, a new generalized Timoshenko model is constructed for a composite rod with embedded or attached piezoelectric materials. This model is applicable to composite rods without prescribed electric potential along the lateral surfaces. The Variational-Asymptotic Method (VAM) is applied as a mathematical tool to carry out the dimensional reduction process. The present reduced model captured the effects

Sitikantha Roy; Wenbin Yu

2009-01-01

414

High-power characteristics of piezoelectric materials  

Microsoft Academic Search

A measuring method of the high-power characteristics of the piezoelectric transducers and some experimental results are described. The vibrational velocity dependences of the equivalent circuit constants and the temperature rise were measured under the constant vibrational velocity control. In addition, when a high-power ultrasonic device such as an ultrasonic motor is practically used, the maximum efficiency is obtained at the

S. Hirose; S. Takahashi; M. Aoyagi; Y. Tomikawa

1994-01-01

415

Miniature piezoelectric triaxial accelerometer measures cranial accelerations  

NASA Technical Reports Server (NTRS)

Tiny triaxial accelerometer whose sensing elements are piezoelectric ceramic beams measures human cranial accelerations when a subject is exposed to a centrifuge or other simulators of g environments. This device could be considered for application in dental, medical, and automotive safety research.

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

1966-01-01

416

Using Piezoelectric Materials for Wearable Electronic Textiles  

E-print Network

Nakad, Tom Martin Virginia Tech Bradley Department of Electrical and Computer Engineering Blacksburg, VA Oct. 8, 2002 Tom Martin, ISWC 2 Overview Introduction Piezoelectric materials Glove prototype-sensing Laminated easier to interface to, produces larger signals #12;Oct. 8, 2002 Tom Martin, ISWC 13 Glove

417

PVPF control of piezoelectric tube scanners  

NASA Astrophysics Data System (ADS)

As in most applications of nanotechnology speed and precision are important requirements for getting good topographical maps of material surfaces using Scanning Tunneling Microscopes (STM) and Atomic Force Microscopes (AFM). Many STMs and AFMs use Piezoelectric tubes for scanning and positioning with nanometer resolution. In this work a piezoelectric tube of the type typically used in STMs and AFMs is considered. Scanning using this piezoelectric tube is hampered by the presence of a low- frequency resonance mode that is easily excited to produce unwanted vibrations. The presence of this low-frequency resonance mode restricts the scanning speed of the piezoelectric tube. Concept of a Positive Velocity and Position Feedback (PVPF) controller is introduced and a controller is designed to dampen the effect of the undesired first resonance mode. To achieve good precision, specific control signals are designed for the closed loop system to track a raster pattern. Experimental results revel a significant damping of the resonance mode of interest, and consequently, a good tracking performance.

Bhikkaji, B.; Ratnam, M.; Moheimani, S. O. R.

2006-03-01

418

Piezoelectric Diffraction-Based Optical Switches  

NASA Technical Reports Server (NTRS)

Piezoelectric diffraction-based optoelectronic devices have been invented to satisfy requirements for switching signals quickly among alternative optical paths in optical communication networks. These devices are capable of operating with switching times as short as microseconds or even nanoseconds in some cases.

Spremo, Stevan; Fuhr, Peter; Schipper, John

2003-01-01

419

History and recent progress in piezoelectric polymers.  

PubMed

Electrets of carnauba wax and resin have exhibited good stability of trapped charges for nearly 50 years. Dipolar orientation and trapped charge are two mechanisms contributing to the pyro-, piezo-, and ferroelectricity of polymers. Since the 1950s, shear piezoelectricity was investigated in polymers of biological origin (such as cellulose and collagen) as well as synthetic optically active polymers (such as polyamides and polylactic acids). Since the discovery of piezoelectricity in poled polyvinylidene fluoride (PVDF) in 1969, the pyro-, piezo-, and ferroelectricity were widely investigated in a number of polar polymers, such as copolymers of vinylidene fluoride and trifluoroethylene, copolymers of vinylcyanide and vinylacetate, and nylons. Recent studies involve submicron films of aromatic and aliphatic polyureas prepared by vapor deposition polymerization in vacuum and the piezoelectricity of polyurethane produced by the coupling of electrostriction and bias electric fields. Gramophone pickups using a piece of bone or tendon were demonstrated in 1959. Microphones using a stretched film of polymethyl glutamate were reported in 1968. Ultrasonic transducers using elongated and poled films of PVDF were demonstrated in 1972. Headphones and tweeters using PVDF were marketed in 1975. Hydrophones and various electromechanical devices utilizing PVDP and its copolymers have been developed during the past 30 years. This paper briefly reviews the history and recent progress in piezoelectric polymers. PMID:18238673

Fukada, E

2000-01-01

420

Piezoelectric nanoribbons for monitoring cellular deformations  

E-print Network

Piezoelectric nanoribbons for monitoring cellular deformations Thanh D. Nguyen1 , Nikhil Deshmukh2 cellular forces agree with a theoretical model in 15 which depolarization caused by an applied voltage a silicone elastomer and measure mechanical defor- 20 mations on a cow lung that mimic respiration

Purohit, Prashant

421

Piezoelectricity in two-dimensional materials.  

PubMed

Powering up 2D materials: Recent experimental studies confirmed the existence of piezoelectricity-the conversion of mechanical stress into electricity-in two-dimensional single-layer MoS2 nanosheets. The results represent a milestone towards embedding low-dimensional materials into future disruptive technologies. PMID:25714055

Wu, Tom; Zhang, Hua

2015-04-01

422

Designing Piezoelectric Films for Micro Electromechanical Systems  

SciTech Connect

Piezoelectric thin films are of increasing interest in low-voltage micro electromechanical systems for sensing, actuation, and energy harvesting. They also serve as model systems to study fundamental behavior in piezoelectrics. Next-generation technologies such as ultrasound pill cameras, flexible ultrasound arrays, and energy harvesting systems for unattended wireless sensors will all benefit from improvements in the piezoelectric properties of the films. This paper describes tailoring the composition, microstructure, orientation of thin films, and substrate choice to optimize the response. It is shown that increases in the grain size of lead-based perovskite films from 75 to 300 nm results in 40 and 20% increases in the permittivity and piezoelectric coefficients, respectively. This is accompanied by an increase in the nonlinearity in the response. Band excitation piezoresponse force microscopy was used to interrogate the nonlinearity locally. It was found that chemical solution-derived PbZr(0.52)Ti(0.48)O(3) thin films show clusters of larger nonlinear response embedded in a more weakly nonlinear matrix. The scale of the clusters significantly exceeds that of the grain size, suggesting that collective motion of many domain walls contributes to the observed Rayleigh behavior in these films. Finally, it is shown that it is possible to increase the energy-harvesting figure of merit through appropriate materials choice, strong imprint, and composite connectivity patterns.

Trolier-McKinstry, Susan [Pennsylvania State University; Griggio, Flavio [Pennsylvania State University; Yaeger, Charles [Pennsylvania State University; Jousse, Pierre [Pennsylvania State University; Zhao, Dalong [Pennsylvania State University; Bharadwaja, Srowthi [Pennsylvania State University; Jackson, Thomas N [Pennsylvania State University; Jesse, Stephen [ORNL; Kalinin, Sergei V [ORNL; Wasa, Kiyotaka [Kyoto University, Japan

2011-01-01

423

Piezoelectric actuation of helicopter rotor blades  

Microsoft Academic Search

The work presented in this paper is concerned with the application of embedded piezo-electric actuators in model helicopter rotor blades. The paper outlines techniques to define the optimal location of actuators to excite particular modes of vibration whilst the blade is rotating. Using composite blades the distribution of strain energy is defined using a Finite Element model with imposed rotor-dynamic

Nicholas A. Lieven

2001-01-01

424

The theory of a piezoelectric disc gyroscope  

Microsoft Academic Search

The theory of a new type of vibratory rate gyroscope is considered. The design considered is based upon a disk of piezoelectric material on which are deposited drive and pick-off electrodes. The equations of motion of the disk are derived and the response of the gyroscope to constant and harmonic rates of turn determined.

J. S. Burdess; T. Wren

1986-01-01

425

Planar Rotary Piezoelectric Motor Using Ultrasonic Horns  

NASA Technical Reports Server (NTRS)

A motor involves a simple design that can be embedded into a plate structure by incorporating ultrasonic horn actuators into the plate. The piezoelectric material that is integrated into the horns is pre-stressed with flexures. Piezoelectric actuators are attractive for their ability to generate precision high strokes, torques, and forces while operating under relatively harsh conditions (temperatures at single-digit K to as high as 1,273 K). Electromagnetic motors (EM) typically have high rotational speed and low torque. In order to produce a useful torque, these motors are geared down to reduce the speed and increase the torque. This gearing adds mass and reduces the efficiency of the EM. Piezoelectric motors can be designed with high torques and lower speeds directly without the need for gears. Designs were developed for producing rotary motion based on the Barth concept of an ultrasonic horn driving a rotor. This idea was extended to a linear motor design by having the horns drive a slider. The unique feature of these motors is that they can be designed in a monolithic planar structure. The design is a unidirectional motor, which is driven by eight horn actuators, that rotates in the clockwise direction. There are two sets of flexures. The flexures around the piezoelectric material are pre-stress flexures and they pre-load the piezoelectric disks to maintain their being operated under compression when electric field is applied. The other set of flexures is a mounting flexure that attaches to the horn at the nodal point and can be designed to generate a normal force between the horn tip and the rotor so that to first order it operates independently and compensates for the wear between the horn and the rotor.

Sherrit, Stewart; Bao, Xiaoqi; Badescu, Mircea; Bar-Cohen, Yoseph; Geiyer, Daniel; Ostlund, Patrick N.; Allen, Phillip

2011-01-01

426

Piezoelectric Surgery -A Novel Technique for Laminectomy.  

PubMed

ABSTRACT Objective: Piezoelectric surgery is a novel technology that allows for the osteotomy of mineralized tissue with less risk of damaging underlying soft tissue structures. This selective cutting increases the safety of osteotomies performed in close vicinity to delicate structures such as dura mater, blood vessels, and neural tissue. This study aimed to develop and describe the technique of piezoelectric surgery for dorsal laminectomy and to assess its clinical safety in normal sheep. Methods: A piezoelectric, dorsal laminectomy technique was developed using ovine cadavers. Following technique development, six live sheep underwent a piezoelectric (n = 6) two-level dorsal laminectomy at L2-L3 and L4-L5 (PiezoL2-3,4-5), and another 30 live sheep underwent a three-level laminectomy at L1, L3, and L5 (PiezoL1,3,5) for a total of 102 laminectomy sites. Surgery time and postoperative complications were recorded. Results: Dorsal laminectomy was safely and accurately performed in 35/36 study sheep using a Piezoelectric surgical instrument. No dural tears were noted in any animal. Non-ambulatory paraparesis in one study sheep (PiezoL1,3,5) led to euthanasia at 48 hr and only mild epidural hematoma was noted on necropsy. No other major postoperative complications were observed in any of the animals. Subjectively, PiezoL was easy to perform and with a rapid learning curve. Mean surgery time was 105min (range: 75-165min; median: 97.5) for PiezoL2-3,4-5 and 93 minutes (range 55-100min; median: 67.5) for PiezoL1,3,5. Conclusions: Based on our study, PiezoL is considered a safe and viable technique for performing ovine dorsal laminectomy in the preclinical research setting. PMID:25438097

Duerr, Felix M; Seim, Howard B; Bascun, Ana L; Palmer, Ross H; Easley, Jeremiah

2014-12-01

427

Contactless ultrasonic energy transfer for wireless systems: acoustic-piezoelectric structure interaction modeling and performance enhancement  

NASA Astrophysics Data System (ADS)

There are several applications of wireless electronic components with little or no ambient energy available to harvest, yet wireless battery charging for such systems is still of great interest. Example applications range from biomedical implants to sensors located in hazardous environments. Energy transfer based on the propagation of acoustic waves at ultrasonic frequencies is a recently explored alternative that offers increased transmitter-receiver distance, reduced loss and the elimination of electromagnetic fields. As this research area receives growing attention, there is an increased need for fully coupled model development to quantify the energy transfer characteristics, with a focus on the transmitter, receiver, medium, geometric and material parameters. We present multiphysics modeling and case studies of the contactless ultrasonic energy transfer for wireless electronic components submerged in fluid. The source is a pulsating sphere, and the receiver is a piezoelectric bar operating in the 33-mode of piezoelectricity with a fundamental resonance frequency above the audible frequency range. The goal is to quantify the electrical power delivered to the load (connected to the receiver) in terms of the source strength. Both the analytical and finite element models have been developed for the resulting acoustic-piezoelectric structure interaction problem. Resistive and resistiveinductive electrical loading cases are presented, and optimality conditions are discussed. Broadband power transfer is achieved by optimal resistive-reactive load tuning for performance enhancement and frequency-wise robustness. Significant enhancement of the power output is reported due to the use of a hard piezoelectric receiver (PZT-8) instead of a soft counterpart (PZT-5H) as a result of reduced material damping. The analytical multiphysics modeling approach given in this work can be used to predict and optimize the coupled system dynamics with very good accuracy and dramatically improved computational efficiency compared to the use of commercial finite element packages.

Shahab, S.; Erturk, A.

2014-12-01

428

Dog-Bone Horns for Piezoelectric Ultrasonic/Sonic Actuators  

NASA Technical Reports Server (NTRS)

A shape reminiscent of a dog bone has been found to be superior to other shapes for mechanical-amplification horns that are components of piezoelectrically driven actuators used in a series of related devices denoted generally as ultrasonic/sonic drill/corers (USDCs). The first of these devices was reported in Ultrasonic/Sonic Drill/Corers With Integrated Sensors (NPO-20856), NASA Tech Briefs, Vol. 25, No. 1 (January 2001), page 38. The dog-bone shape was conceived especially for use in a more recent device in the series, denoted an ultrasonic/ sonic gopher, that was described in Ultrasonic/Sonic Mechanisms for Drilling and Coring (NPO-30291), NASA Tech Briefs, Vol. 27, No. 9 (September 2003), page 65. The figure shows an example of a dog-bone-shaped horn and other components of an ultrasonic gopher. Prerequisite to a meaningful description of this development is an unavoidably lengthy recapitulation of the principle of operation of a USDC and, more specifically, of the ultrasonic/sonic gopher as described previously in NASA Tech Briefs. The ultrasonic actuator includes a stack of piezoelectric rings, the horn, a metal backing, and a bolt that connects the aforementioned parts and provides compressive pre-strain to the piezoelectric stack to prevent breakage of the rings during extension. The stack of piezoelectric rings is excited at the resonance frequency of the overall ultrasonic actuator. Through mechanical amplification by the horn, the displacement in the ultrasonic vibration reaches tens of microns at the tip of the horn. The horn hammers an object that is denoted the free mass because it is free to move longitudinally over a limited distance between hard stops: The free mass bounces back and forth between the ultrasonic horn and a tool bit (a drill bit or a corer). Because the longitudinal speed of the free mass is smaller than the longitudinal speed of vibration of the tip of the horn, contact between the free mass and the horn tip usually occurs at a phase of the vibration favorable to transfer of momentum from the horn to the free mass. Therefore, the free mass picks up momentum and is accelerated back to the tool bit. Upon impact of the free mass on the tool bit, momentum is transferred to the tool bit. The impacts of the free mass on the tool bit repeat at a sonic frequency that can range from tens of hertz to about 1 kHz. The shock waves caused by the impacts of the free mass propagate to the interface between the tool bit and the medium (typically, rock, ice, or other brittle material) to be drilled or cored. The medium becomes fractured when its ultimate strain is exceeded at the medium/tool-bit interface. This concludes the description of the principle of operation.

Sherrit, Stewart; Bar-Cohen, Yoseph; Chang, Zensheu; Bao, Xiaoqi

2007-01-01

429

Piezoelectric energy harvesting: State-of-the-art and challenges  

NASA Astrophysics Data System (ADS)

Piezoelectric energy harvesting has attracted wide attention from researchers especially in the last decade due to its advantages such as high power density, architectural simplicity, and scalability. As a result, the number of studies on piezoelectric energy harvesting published in the last 5 years is more than twice the sum of publications on its electromagnetic and electrostatic counterparts. This paper presents a comprehensive review on the history and current state-of-the art of piezoelectric energy harvesting. A brief theory section presents the basic principles of piezoelectric energy conversion and introduces the most commonly used mechanical architectures. The theory section is followed by a literature survey on piezoelectric energy harvesters, which are classified into three groups: (i) macro- and mesoscale, (ii) MEMS scale, and (iii) nanoscale. The size of a piezoelectric energy harvester affects a variety of parameters such as its weight, fabrication method, achievable power output level, and potential application areas. Consequently, size-based classification provides a reliable and effective basis to study various piezoelectric energy harvesters. The literature survey on each scale group is concluded with a summary, potential application areas, and future directions. In a separate section, the most prominent challenges in piezoelectric energy harvesting and the studies focusing on these challenges are discussed. The conclusion part summarizes the current standing of piezoelectric energy harvesters as possible candidates for various applications and discusses the issues that need to be addressed for realization of practical piezoelectric energy harvesting devices.

Toprak, Alperen; Tigli, Onur

2014-09-01

430

Lead-free and lead-based ABO3 perovskite relaxors with mixed-valence A-site and B-site disorder: A comparative neutron scattering structural study of (Na1/2Bi1/2)TiO3 and Pb(Mg1/3Nb2/3)O3  

SciTech Connect

We report the results of neutron elastic scattering measurements between -250oC and 620oC on the lead-free relaxor Na1/2Bi1/2TiO3 (NBT). Strong, anisotropic, elastic diffuse scattering intensity decorates the (100), (110), (111), (200), (220), and (210) Bragg peaks at room temperature. The wavevector dependence of this diffuse scattering is compared to that in the lead-based relaxor PbMg1/3Nb2/3O3 (PMN) to determine if any features might be common to relaxors. Prominent ridges in the elastic diffuse scattering intensity contours that extend along <110> are seen that exhibit the same zone dependence as those observed in PMN and other lead-based relaxors. These ridges disappear gradually on heating above the cubic-to-tetragonal phase transition temperature TCT = 523oC, which is also near the temperature at which the dielectric permittivity begins to deviate from Curie-Weiss behavior. We thus identify the <110>-oriented ridges as a relaxor-specific property. The diffuse scattering contours also display narrower ridges oriented along <100> that are consistent with the x-ray results of Kreisel et al. (2003); these vanish below 320oC indicating that they have a different physical origin. The <100>-oriented ridges are not observed in PMN. We observe no equivalent relaxor-specific elastic diffuse scattering from the homovalent relaxor analogues K0.95Li0.05TiO3 (A-site disordered) and KTa0.95Nb0.05O3 (B-site disordered). This suggests that the <110>-oriented diffuse scattering ridges are correlated with the presence of strong random electric fields and invites a reassessment of what defines the relaxor phase. We find that doping NBT with 5.6% BaTiO3, a composition close to the morphotropic phase boundary with enhanced piezoelectric properties, increases the room temperature correlation length along [1 1 0] from 40 to 60 while doubling the associated integrated diffuse scattering. Similar behavior was reported by Matsuura et al. (2006) for compositions of PMN doped with PbTiO3. Finally, we comment on the recent observation of monoclinicity in NBT at room temperature by placing a strict bound on the strength of the ( ) superlattice reflection associated with the Cc space group based on the atomic coordinates published in the x-ray study by Aksel et al. (2011) for NBT. We argue that a skin effect, analogous to that reported in the relaxors PZN and PMN-10%PT, can reconcile our single-crystal data with the powder data of Aksel et al. We believe this represents the first evidence of the relaxor skin effect in a lead-free relaxor.

Ge, Wenwei [Virginia Polytechnic Institute and State University] [Virginia Polytechnic Institute and State University; Devreugd, Christopher [Virginia Polytechnic Institute and State University] [Virginia Polytechnic Institute and State University; Phelan, Daniel [National Institute of Standards and Technology (NIST), Gaithersburg, MD] [National Institute of Standards and Technology (NIST), Gaithersburg, MD; Zhang, Qinjui [Shanghai Institute of Ceramics, Chinese Academy of Sciences (SICCAS)] [Shanghai Institute of Ceramics, Chinese Academy of Sciences (SICCAS); Muhtar, Aheart [Carnegie Institution of Washington] [Carnegie Institution of Washington; Li, Jiefang [Virginia Polytechnic Institute and State University] [Virginia Polytechnic Institute and State University; Luo, Haosu [Shanghai Institute of Ceramics, Chinese Academy of Sciences (SICCAS)] [Shanghai Institute of Ceramics, Chinese Academy of Sciences (SICCAS); Boatner, Lynn A [ORNL] [ORNL; Viehland, Dwight [Virginia Polytechnic Institute and State University] [Virginia Polytechnic Institute and State University; Gehring, P. M. [National Institute of Standards and Technology (NIST)] [National Institute of Standards and Technology (NIST)

2013-01-01

431

Using piezoelectric sensors for ultrasonic pulse velocity measurements in concrete  

NASA Astrophysics Data System (ADS)

The ultrasonic pulse velocity (UPV) test has been a widely used non-destructive testing method for concrete structures. However, the conventional UPV test has limitations in consistency of results and applicability in hard-to-access regions of structures. The authors explore the feasibility of embedded piezoelectric (PZT) sensors for ultrasonic measurements in concrete structures. Two PZT sensors were embedded in a reinforced concrete specimen. One sensor worked as an actuator driven by an ultrasonic pulse-receiver, and another sensor worked as a receiver. A series of ultrasonic tests were conducted to investigate the performance of the embedded sensors in crack-free concrete and concrete specimens having a surface-breaking crack under various external loadings. Signals measured by the embedded sensors show a broad bandwidth with a centre frequency around 80 kHz, and very good coherence in the frequency range from 30 to 180 kHz. Furthermore, experimental variability in ultrasonic pulse velocity and attenuation is substantially reduced compared to previously reported values from conventional UPV equipment. Findings from this study demonstrate that the embedded sensors have great potential as a low-cost solution for ultrasonic transducers for health monitoring of concrete in structures.

Kee, Seong-Hoon; Zhu, Jinying

2013-11-01

432

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

E-print Network

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

Cao, Wenwu

433

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

E-print Network

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

Boyer, Edmond

434

Engineering domain configurations for enhanced piezoelectricity in barium titanate single crystals  

E-print Network

Engineering domain configurations for enhanced piezoelectricity in barium titanate single crystals piezoelectric responses of barium titanate single crystals under different crystallographic orientations, and use it to explain the ultrahigh piezoelectric response recently observed in a 270 cut barium titanate

Li, Jiangyu

435

Frequency Rectification Applied to Piezoelectric Energy Harvesting and Improving Available Power of Piezoelectric Motors  

NASA Astrophysics Data System (ADS)

Piezoelectric materials are just now, within the last decade, coming into their own as a commercial material. Capable of converting energy from the mechanical domain to the electrical domain; piezos are ideal sensors, vibration dampers, energy harvesters, and actuators. Frequency rectification, or the conversion of small, high frequency piezoelectric vibrations into useful low frequency actuation, is required to obtain widespread industrial use of piezoelectric devices. This work examines three manifestations of piezoelectric frequency rectification: energy harvesting, a hydraulic motor, and friction based commercial-off-the-shelf motors. An energy harvesting device is developed, manufactured, and tested in this work, resulting in the development of a high Energy Density (J/m 3), high Power Density (W/m3) energy harvester. The device is shown to have an Energy Density nearly twice that of a similar conventional energy harvesting device. The result of this work is the development of an energy harvesting system that generates more energy in a given volume of piezoelectric material, opening the possibility of miniaturization of energy harvesting devices. Also presented is an effort to integrate a high frequency, high flow rate micromachined valve array into a PiezoHydraulic Pump (PHP), enabling resonant operation of the PHP. Currently, the device is limited by the resonant frequency of the proprietary passive check valves. The PHP is fully characterized, and the microvalve array is tested to determine its resonant frequency in a fluid medium. The valve testing resulted in a resonant frequency of 6.9 kHz, slightly lower than the target operating frequency of 10 kHz. Finally, the results of an examination of frequency rectification as applied to COTS piezoelectric motors are presented. Currently, motors are almost universally characterized based upon their available mechanical power. A better comparison is one based upon the actual Energy Density of the piezoelectric material utilized in the motor compared to the theoretical maximum Energy Density under the motor operating conditions (i.e., frequency, applied electric field). The result of this work is a more descriptive metric to evaluate piezoelectric motors that provides information on the effectiveness of the motor drive train; that is, how effectively the motion of the piezoelectric is transferred to the outside world.

Kuroda, Kazuaki; LCGT Collaboration

436

Structure-Property Study of Piezoelectricity in Polyimides  

NASA Technical Reports Server (NTRS)

High performance piezoelectric polymers are of interest to NASA as they may be useful for a variety of sensor applications. Over the past few years research on piezoelectric polymers has led to the development of promising high temperature piezoelectric responses in some novel polyimides. In this study, a series of polyimides have been studied with systematic variations in the diamine monomers that comprise the polyimide while holding the dianhydride constant. The effect of structural changes, including variations in the nature and concentration of dipolar groups, on the remanent polarization and piezoelectric coefficient is examined. Fundamental structure-piezoelectric property insight will enable the molecular design of polymers possessing distinct improvements over state-of-the-art piezoelectric polymers including enhanced polarization, polarization stability at elevated temperatures, and improved processability.

Ounaies, Zoubeida; Park, Cheol; Harrison, Joycelyn S.; Smith, Joseph G.; Hinkley, Jeffrey

1999-01-01

437

Vibration analysis of composite laminate plate excited by piezoelectric actuators.  

PubMed

Piezoelectric materials can be used as actuators for the active vibration control of smart structural systems. In this work, piezoelectric patches are surface bonded to a composite laminate plate and used as vibration actuators. A static analysis based on the piezoelectricity and elasticity is conducted to evaluate the loads induced by the piezoelectric actuators to the host structure. The loads are then employed to develop the vibration response of a simply supported laminate rectangular plate excited by piezoelectric patches subjected to time harmonic voltages. An analytical solution of the vibration response of a simply supported laminate rectangular plate under time harmonic electrical loading is obtained and compared with finite element results to validate the present approach. The effects of location and exciting frequency of piezoelectric actuators on the vibration response of the laminate plate are investigated through a parametric study. Numerical results show that modes can be selectively excited, leading to structural vibration control. PMID:23529121

Her, Shiuh-Chuan; Lin, Chi-Sheng

2013-01-01

438

Nonlinear kinematics for piezoelectricity in ALEGRA-EMMA.  

SciTech Connect

This report develops and documents nonlinear kinematic relations needed to implement piezoelectric constitutive models in ALEGRA-EMMA [5], where calculations involving large displacements and rotations are routine. Kinematic relationships are established using Gauss's law and Faraday's law; this presentation on kinematics goes beyond piezoelectric materials and is applicable to all dielectric materials. The report then turns to practical details of implementing piezoelectric models in an application code where material principal axes are rarely aligned with user defined problem coordinate axes. This portion of the report is somewhat pedagogical but is necessary in order to establish documentation for the piezoelectric implementation in ALEGRA-EMMA. This involves transforming elastic, piezoelectric, and permittivity moduli from material principal axes to problem coordinate axes. The report concludes with an overview of the piezoelectric implementation in ALEGRA-EMMA and small verification examples.

Mitchell, John Anthony; Fuller, Timothy Jesse

2013-09-01

439

How Hard is Chocolate?  

NSDL National Science Digital Library

Hardness is probably a concept you are well familiar with. You already know that certain materials are harder than others; in fact, you prove it everyday when you chew your food and your teeth dont break (because your teeth are harder than the foods you chew). Hardness can be defined as a material's ability to resist a change in shape. Modern hardness testers take a well-defined shape and press it into a material with a certain force, observing the indent it leaves in the material when it is removed. In this lesson, you will be performing hardness testing on different bars of chocolate.

2007-12-20

440

New solutions of shear waves in piezoelectric cubic crystals  

Microsoft Academic Search

Acoustic wave propagation in piezoelectric crystals of classes?43m and 23 is studied. The crystals Tl3VS4 and Tl3TaSe 4 (43m) of the Chalcogenide family and the crystal Bi12TiO20 (23) possess strong piezoelectric effect. Because the surface Bleustein-Gulyaev waves cannot exist in piezoelectric cubic crystals, it was concluded that new solutions for shear-horizontal surface acoustic waves (SH-SAWs) are found in the monocrystals

441

Polarization and Piezoelectric Properties of a Nitrile Substituted Polyimide  

NASA Technical Reports Server (NTRS)

This research focuses on the synthesis and characterization of a piezoelectric (beta-CN)- APB/ODPA polyimide. The remanent polarization and piezoelectric d(sub 31) and g(sub 33) coefficients are reported to assess the effect of synthesis variations. Each of the materials exhibits a level of piezoelectricity which increases with temperature. The remanent polarization is retained at temperatures close to the glass transition temperature of the polyimide.

Simpson, Joycelyn; Ounaies, Zoubeida; Fay, Catharine

1997-01-01

442

High-Performance 4Node Shell Element with Piezoelectric Coupling  

Microsoft Academic Search

The paper focuses on the topic of smart and adaptive structures using embedded piezoelectric sensors and actuators. A new high-performance degenerated continuum based solid piezoelectric shell element is developed herein. It is an isoparametric 4-noded quadrilateral layered element based on the Reissner-Mindlin theory of plates with piezoelectric coupling. It assumes linear elasticity and small displacements, rotations and strains theories. The

Robert Zem?k; Raimund Rolfes; Michael Rose; Jan Tessmer

2006-01-01

443

Ordering of hard particles between hard walls  

NASA Astrophysics Data System (ADS)

The structure of a fluid of hard Gaussian overlap particles of elongation ? = 5, confined between two hard walls, has been calculated from density-functional theory and Monte Carlo simulations. By using the exact expression for the excluded volume kernel (Velasco E and Mederos L 1998 J. Chem. Phys. 109 2361) and solving the appropriate Euler-Lagrange equation entirely numerically, we have been able to extend our theoretical predictions into the nematic phase, which had up till now remained relatively unexplored due to the high computational cost. Simulation reveals a rich adsorption behaviour with increasing bulk density, which is described semi-quantitatively by the theory without any adjustable parameters.

Chrzanowska, A.; Teixeira, P. I. C.; Ehrentraut, H.; Cleaver, D. J.

2001-05-01

444

Piezoelectric film load cell robot collision detector  

DOEpatents

A piezoelectric load cell which can be utilized for detecting collisions and obstruction of a robot arm end effector includes a force sensing element of metallized polyvinylidene fluoride (PVDF) film. The piezoelectric film sensing element and a resilient support pad are clamped in compression between upper and lower plates. The lower plate has a central recess in its upper face for supporting the support pad and sensing element, while the upper plate has a corresponding central projection formed on its lower face for bearing on the sensing element and support pad. The upper and lower plates are dowelled together for concentric alignment and screwed together. The upper and lower plates are also adapted for mounting between the robot arm wrist and end effector.

Lembke, John R. (Overland Park, KS)

1989-04-18

445

Piezoelectric film load cell robot collision detector  

DOEpatents

A piezoelectric load cell which can be utilized for detecting collisions and obstruction of a robot arm end effector includes a force sensing element of metallized polyvinylidene fluoride (PVDF) film. The piezoelectric film sensing element and a resilient support pad are clamped in compression between upper and lower plates. The lower plate has a central recess in its upper face for supporting the support pad and sensing element, while the upper plate has a corresponding central projection formed on its lower face for bearing on the sensing element and support pad. The upper and lower plates are doweled together for concentric alignment and screwed together. The upper and lower plates are also adapted for mounting between the robot arm wrist and end effector. 3 figs.

Lembke, J.R.

1989-04-18

446

Elastomer degradation sensor using a piezoelectric material  

DOEpatents

A method and apparatus for monitoring the degradation of elastomeric materials is provided. Piezoelectric oscillators are placed in contact with the elastomeric material so that a forced harmonic oscillator with damping is formed. The piezoelectric material is connected to an oscillator circuit,. A parameter such as the resonant frequency, amplitude or Q value of the oscillating system is related to the elasticity of the elastomeric material. Degradation of the elastomeric material causes changes in its elasticity which, in turn, causes the resonant frequency, amplitude or Q of the oscillator to change. These changes are monitored with a peak height monitor, frequency counter, Q-meter, spectrum analyzer, or other measurement circuit. Elasticity of elastomers can be monitored in situ, using miniaturized sensors.

Olness, Dolores U. (Livermore, CA); Hirschfeld, deceased, Tomas B. (late of Livermore, CA)

1990-01-01

447

Cantilevered probe detector with piezoelectric element  

DOEpatents

A disclosed chemical detection system for detecting a target material, such as an explosive material, can include a cantilevered probe, a probe heater coupled to the cantilevered probe, and a piezoelectric element disposed on the cantilevered probe. The piezoelectric element can be configured as a detector and/or an actuator. Detection can include, for example, detecting a movement of the cantilevered probe or a property of the cantilevered probe. The movement or a change in the property of the cantilevered probe can occur, for example, by adsorption of the target material, desorption of the target material, reaction of the target material and/or phase change of the target material. Examples of detectable movements and properties include temperature shifts, impedance shifts, and resonant frequency shifts of the cantilevered probe. The overall chemical detection system can be incorporated, for example, into a handheld explosive material detection system.

Adams, Jesse D.; Sulchek, Todd A.; Feigin, Stuart C.

2010-04-06

448

Torque for an Inertial Piezoelectric Rotary Motor  

PubMed Central

For a novel inertial piezoelectric rotary motor, the equation of the strain energy in the piezoceramic bimorph and the equations of the strain energy and the kinetic energy in the rotor are given. Based on them, the dynamic equation of the motor is obtained. Using these equations, the inertial driving torque of the motor is investigated. The results show that the impulsive driving torque changes with changing peak voltage of the excitation signal, the piezoelectric stress constant, the thickness of the piezoceramic bimorph, and the rotor radius obviously. Tests about the motor torque are completed which verifies the theory analysis here in. The results can be used to design the operating performance of the motor. PMID:24470794

Xing, Jichun

2013-01-01

449

Cantilevered probe detector with piezoelectric element  

DOEpatents

A disclosed chemical detection system for detecting a target material, such as an explosive material, can include a cantilevered probe, a probe heater coupled to the cantilevered probe, and a piezoelectric element disposed on the cantilevered probe. The piezoelectric element can be configured as a detector and/or an actuator. Detection can include, for example, detecting a movement of the cantilevered probe or a property of the cantilevered probe. The movement or a change in the property of the cantilevered probe can occur, for example, by adsorption of the target material, desorption of the target material, reaction of the target material and/or phase change of the target material. Examples of detectable movements and properties include temperature shifts, impedance shifts, and resonant frequency shifts of the cantilevered probe. The overall chemical detection system can be incorporated, for example, into a handheld explosive material detection system.

Adams, Jesse D. (Reno, NV); Sulchek, Todd A. (Oakland, CA); Feigin, Stuart C. (Reno, NV)

2012-07-10

450

Thermally Stable, Piezoelectric and Pyroelectric Polymeric Substrates  

NASA Technical Reports Server (NTRS)

A thermally stable, piezoelectric and pyroelectric polymeric substrate was prepared. This thermally stable, piezoelectric and pyroelectric polymeric substrate may be used to prepare electromechanical transducers, thermomechanical transducers, accelerometers. acoustic sensors, infrared sensors, pressure sensors, vibration sensors, impact sensors, in-situ temperature sensors, in-situ stress/strain sensors, micro actuators, switches, adjustable fresnel lenses, speakers, tactile sensors. weather sensors, micro positioners, ultrasonic devices, power generators, tunable reflectors, microphones, and hydrophones. The process for preparing these polymeric substrates includes: providing a polymeric substrate having a softening temperature greater than 1000 C; depositing a metal electrode material onto the polymer film; attaching a plurality of electrical leads to the metal electrode coated polymeric substrate; heating the metal electrode coated polymeric substrate in a low dielectric medium; applying a voltage to the heated metal electrode coated polymeric substrate to induce polarization; and cooling the polarized metal electrode coated polymeric electrode while maintaining a constant voltage.

Simpson, Joycely O. (Inventor); St.Clair, Terry L. (Inventor)

1999-01-01

451

Cantilevered probe detector with piezoelectric element  

DOEpatents

A disclosed chemical detection system for detecting a target material, such as an explosive material, can include a cantilevered probe, a probe heater coupled to the cantilevered probe, and a piezoelectric element disposed on the cantilevered probe. The piezoelectric element can be configured as a detector and/or an actuator. Detection can include, for example, detecting a movement of the cantilevered probe or a property of the cantilevered probe. The movement or a change in the property of the cantilevered probe can occur, for example, by adsorption of the target material, desorption of the target material, reaction of the target material and/or phase change of the target material. Examples of detectable movements and properties include temperature shifts, impedance shifts, and resonant frequency shifts of the cantilevered probe. The overall chemical detection system can be incorporated, for example, into a handheld explosive material detection system.

Adams, Jesse D; Sulchek, Todd A; Feigin, Stuart C

2013-04-30

452

Cantilevered probe detector with piezoelectric element  

DOEpatents

A disclosed chemical detection system for detecting a target material, such as an explosive material, can include a cantilevered probe, a probe heater coupled to the cantilevered probe, and a piezoelectric element disposed on the cantilevered probe. The piezoelectric element can be configured as a detector and/or an actuator. Detection can include, for example, detecting a movement of the cantilevered probe or a property of the cantilevered probe. The movement or a change in the property of the cantilevered probe can occur, for example, by adsorption of the target material, desorption of the target material, reaction of the target material and/or phase change of the target material. Examples of detectable movements and properties include temperature shifts, impedance shifts, and resonant frequency shifts of the cantilevered probe. The overall chemical detection system can be incorporated, for example, into a handheld explosive material detection system.

Adams, Jesse D; Sulchek, Todd A; Feigin, Stuart C

2014-04-29

453

Piezoelectric film load cell robot collision detector  

DOEpatents

A piezoelectric load cell which can be utilized for detecting collisions and obstruction of a robot arm end effector includes a force sensing element of metallized polyvinylidene fluoride (PVDF) film. The piezoelectric film sensing element and a resilient support pad are clamped in compression between upper and lower plates. The lower plate has a central recess in its upper face for supporting the support pad and sensing element, while the upper plate has a corresponding central projection formed on its lower face for bearing on the sensing element and support pad. The upper and lower plates are dowelled together for concentric alignment and screwed together. The upper and lower plates are also adapted for mounting between the robot arm wrist and end effector. 3 figs.

Lembke, J.R.

1988-03-15

454

Enhanced piezoelectric performance from carbon fluoropolymer nanocomposites  

NASA Astrophysics Data System (ADS)

The piezoelectric performance of polyvinylidene fluoride (PVDF) is shown to double through the controlled incorporation of carbon nanomaterial. Specifically, PVDF composites containing carbon fullerenes (C60) and single-walled carbon nanotubes (SWNT) are fabricated over a range of compositions and optimized for their Young's modulus, dielectric constant, and d31 piezoelectric coefficient. Thermally stimulated current measurements show a large increase in internal charge and polarization in the composites over pure PVDF. The electromechanical coupling coefficients (k31) at optimal loading levels are found to be 1.84 and 2 times greater than pure PVDF for the PVDF-C60 and PVDF-SWNT composites, respectively. Such property-enhanced nanocomposites could have significant benefit to electromechanical systems employed for structural sensing, energy scavenging, sonar, and biomedical imaging.

Baur, Cary; DiMaio, Jeffrey R.; McAllister, Elliot; Hossini, Reza; Wagener, Earl; Ballato, John; Priya, Shashank; Ballato, Arthur; Smith, Dennis W.

2012-12-01

455

Energy Harvesting Using PVDF Piezoelectric Nanofabric  

NASA Astrophysics Data System (ADS)

Energy harvesting using piezoelectric nanomaterial provides an opportunity for advancement towards self-powered electronics. The fabrication complexities and limited power output of these nano/micro generators have hindered these advancements thus far. This thesis presents a fabrication technique with electrospinning using a grounded cylinder as the collector. This method addresses the difficulties with the production and scalability of the nanogenerators. The non-aligned nanofibers are woven into a textile form onto the cylindrical drum that can be easily removed. The electrical poling and mechanical stretching induced by the electric field and the drum rotation increase the concentration of the piezoelectric beta phase in the PVDF nanofabric. The nanofabric is placed between two layers of polyethylene terephthalate (PET) that have interdigitated electrodes painted on them with silver paint. Applying continuous load onto the flexible PVDF nanofabric at 35Hz produces a peak voltage of 320 mV and maximum power of 2200 pW/(cm2) .

Shafii, Chakameh Shafii

456

Frequency modulation drive for a piezoelectric motor  

DOEpatents

A piezoelectric motor has peak performance at a specific frequency f.sub.1 that may vary over a range of frequencies. A drive system is disclosed for operating such a motor at peak performance without feedback. The drive system consists of the motor and an ac source connected to power the motor, the ac source repeatedly generating a frequency over a range from f.sub.1 -.DELTA.x to f.sub.1 +.DELTA.y.

Mittas, Anthony (Albuquerque, NM)

2001-01-01

457

Piezoelectric Hydraulic Pump System Dynamic Model  

Microsoft Academic Search

A system dynamic model was developed for use in the design of piezohydraulic pumps. The model was implemented in MATLAB to predict the electrical\\/mechanical\\/fluid coupled behavior of the piezoelectric pump system. Model results were used in a performance assessment of a pumping system that was comprised of a stack actuator driven pump, accumulator, power supply, four-way valve, and hydraulic actuator.

William S. Oates; Christopher S. Lynch

2001-01-01

458

Piezoelectric properties of aligned collagen membranes.  

PubMed

Electromechanical coupling, a phenomenon present in collagenous materials, may influence cell-extracellular matrix interactions. Here, electromechanical coupling has been investigated via piezoresponse force microscopy in transparent and opaque membranes consisting of helical-like arrays of aligned type I collagen fibrils self-assembled from acidic solution. Using atomic force microscopy, the transparent membrane was determined to contain fibrils having an average diameter of 76 14 nm, whereas the opaque membrane comprised fibrils with an average diameter of 391 99 nm. As the acidity of the membranes must be neutralized before they can serve as cell culture substrates, the structure and piezoelectric properties of the membranes were measured under ambient conditions before and after the neutralization process. A crimp structure (1.59 0.37 m in width) perpendicular to the fibril alignment became apparent in the transparent membrane when the pH was adjusted from acidic (pH = 2.5) to neutral (pH = 7) conditions. In addition, a 1.35-fold increase was observed in the amplitude of the shear piezoelectricity of the transparent membrane. The structure and piezoelectric properties of the opaque membrane were not significantly affected by the neutralization process. The results highlight the presence of an additional translational order in the transparent membrane in the direction perpendicular to the fibril alignment. The piezoelectric response of both membrane types was found to be an order of magnitude lower than that of collagen fibrils in rat tail tendon. This reduced response is attributed to less-ordered molecular assembly than is present in D-periodic collagen fibrils, as evidenced by the absence of D-periodicity in the membranes. PMID:24030958

Denning, D; Paukshto, M V; Habelitz, S; Rodriguez, B J

2014-02-01

459

Piezoelectric films for high frequency ultrasonic transducers in biomedical applications  

PubMed Central

Piezoelectric films have recently attracted considerable attention in the development of various sensor and actuator devices such as nonvolatile memories, tunable microwave circuits and ultrasound transducers. In this paper, an overview of the state of art in piezoelectric films for high frequency transducer applications is presented. Firstly, the basic principles of piezoelectric materials and design considerations for ultrasound transducers will be introduced. Following the review, the current status of the piezoelectric films and recent progress in the development of high frequency ultrasonic transducers will be discussed. Then details for preparation and structure of the materials derived from piezoelectric thick film technologies will be described. Both chemical and physical methods are included in the discussion, namely, the solgel approach, aerosol technology and hydrothermal method. The electric and piezoelectric properties of the piezoelectric films, which are very important for transducer applications, such as permittivity and electromechanical coupling factor, are also addressed. Finally, the recent developments in the high frequency transducers and arrays with piezoelectric ZnO and PZT thick film using MEMS technology are presented. In addition, current problems and further direction of the piezoelectric films for very high frequency ultrasound application (up to GHz) are also discussed. PMID:21720451

Zhou, Qifa; Lau, Sienting; Wu, Dawei; Shung, K. Kirk

2011-01-01

460

Piezoelectric biosensor with a ladder polymer substrate coating  

DOEpatents

A piezoelectric biosensor substrate useful for immobilizing biomolecules in an oriented manner on the surface of a piezoelectric sensor has a ladder polymer of polyacrylonitrile. To make the substrate, a solution of an organic polymer, preferably polyacrylonitrile, is applied to the surface of a piezoelectric sensor. The organic polymer is modifying by heating the polymer in a controlled fashion in air such that a ladder polymer is produced which, in turn, forms the attachment point for the biomolecules comprising the piezoelectric biosensor. 3 figs.

Renschler, C.L.; White, C.A.; Carter, R.M.

1998-09-29