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1

Characterization of Hard Piezoelectric Lead-Free Ceramics  

PubMed Central

K4CuNb8O23 doped K0.45Na0.55NbO3 (KNN-KCN) ferroelectric ceramics were found to exhibit asymmetrical polarization hysteresis loops, related to the development of an internal bias field. The internal bias field is believed to be the result of defect dipoles of acceptor ions and oxygen vacancies, which lead to piezoelectric hardening effect, by stabilizing and pinning of the domain wall motion. The dielectric loss for the hard lead-free piezoelectric ceramic was found to be 0.6%, with mechanical quality factors Q on the order of >1500. Furthermore, the piezoelectric properties were found to decrease and the coercive field increased, when compared with the undoped material, exhibiting a typical characteristic of hard behavior. The temperature usage range was limited by the polymorphic phase transition temperature, being 188C. The full set of material constants was determined for the KNN-KCN materials. Compared with conventional hard PZT ceramics, the lead-free possessed lower dielectric and piezoelectric properties; however, comparable values of mechanical Q, dielectric loss, and coercive fields were obtained, making acceptor modified KNN based lead-free piezoelectric material promising for high-power applications, where lead-free materials are desirable. PMID:19686966

Zhang, Shujun; Lim, Jong Bong; Lee, Hyeong Jae; Shrout, Thomas R.

2010-01-01

2

Characterization of hard piezoelectric lead-free ceramics.  

PubMed

K4CuNb8O23 doped K(0.45)Na(0.55)NbO3(KNNKCN) ferroelectric ceramics were found to exhibit asymmetrical polarization hysteresis loops, related to the development of an internal bias field. The internal bias field is believed to be the result of defect dipoles of acceptor ions and oxygen vacancies, which lead to piezoelectric "hardening" effect, by stabilizing and pinning of the domain wall motion. The dielectric loss for the hard lead-free piezoelectric ceramic was found to be 0.6%, with mechanical quality factors Q on the order of >1500. Furthermore, the piezoelectric properties were found to decrease and the coercive field increased, when compared with the undoped material, exhibiting a typical characteristic of "hard" behavior. The temperature usage range was limited by the polymorphic phase transition temperature, being 188 degrees C. The full set of material constants was determined for the KNN-KCN materials. Compared with conventional hard PZT ceramics, the lead-free possessed lower dielectric and piezoelectric properties; however, comparable values of mechanical Q, dielectric loss, and coercive fields were obtained, making acceptor modified KNN based lead-free piezoelectric material promising for high-power applications, where leadfree materials are desirable. PMID:19686966

Zhang, Shujun; Lim, Jong Bong; Lee, Hyeong Jae; Shrout, Thomas R

2009-08-01

3

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

4

Development, Characterization and Piezoelectric Fatigue Behavior of Lead-Free Perovskite Piezoelectric Ceramics  

NASA Astrophysics Data System (ADS)

Much recent research has focused on the development lead-free perovskite piezoelectrics as environmentally compatible alternatives to lead zirconate titanate (PZT). Two main categories of lead free perovskite piezoelectric ceramic systems were investigated as potential replacements to lead zirconate titanate (PZT) for actuator devices. First, solid solutions based on Li, Ta, and Sb modified (K0.5Na0.5)NbO3 (KNN) lead-free perovskite systems were created using standard solid state methods. Secondly, Bi-based materials a variety of compositions were explored for (1-x)(Bi 0.5Na0.5)TiO3-xBi(Zn0.5Ti0.5)O 3 (BNT-BZT) and Bi(Zn0.5Ti0.5)O3-(Bi 0.5K0.5)TiO3-(Bi0.5Na0.5)TiO 3 (BZT-BKT-BNT). It was shown that when BNT-BKT is combined with increasing concentrations of Bi(Zn1/2i1/2)O3 (BZT), a transition from normal ferroelectric behavior to a material with large electric field induced strains was observed. The higher BZT containing compositions are characterized by large hysteretic strains(> 0.3%) with no negative strains that might indicate domain switching. This work summarizes and analyzes the fatigue behavior of the new generation of Pb-free piezoelectric materials. In piezoelectric materials, fatigue is observed as a degradation in the electromechanical properties under the application of a bipolar or unipolar cyclic electrical load. In Pb-based materials such as lead zirconate titanate (PZT), fatigue has been studied in great depth for both bulk and thin film applications. In PZT, fatigue can result from microcracking or electrode effects (especially in thin films). Ultimately, however, it is electronic and ionic point defects that are the most influential mechanism. Therefore, this work also analyzes the fatigue characteristics of bulk polycrystalline ceramics of the modified-KNN and BNT-BKT-BZT compositions developed. The defect chemistry that underpins the fatigue behavior will be examined and the results will be compared to the existing body of work on PZT. It will be demonstrated that while some Pb-free materials show severe property degradation under cyclic loading, other materials such as BNT-BKT-BZT essentially exhibit fatigue- free piezoelectric properties with chemical doping or other modifications. Based on these results, these new Pb-free materials have great potential for use in piezoelectric applications requiring a large number of drive cycles such as MEMS devices or high frequency actuators.

Patterson, Eric Andrew

5

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

6

Reliability of Nickel Inner Electrode Lead-Free Multilayer Piezoelectric Ceramics  

NASA Astrophysics Data System (ADS)

The environmental reliability of lead-free (K,Na)NbO3-based multilayer ceramics with nickel inner electrodes was studied. The multilayer specimen with good piezoelectric properties was successfully obtained by adding excess zirconium to a (K,Na)NbO3-based composition. Excess zirconium probably accelerated the solid solution of potassium into the crystal lattice and prevented potassium evaporation. The electric resistivity and piezoelectric properties of the ceramics were extremely stable at a high temperature (85 C), a low temperature (-40 C), and a high humidity [85 C/85% relative humidity (RH)]. Their change rates were below 10% in 500 h studies. The stability was also high in the thermal shock (from -40 to 85 C) test. It is thus concluded that the (K,Na)NbO3-based composition containing excess zirconium is a good candidate material for nickel electrode multilayer ceramics.

Hayashi, Hiroyuki; Kawada, Shinichiro; Kimura, Masahiko; Nakai, Yoshihiro; Tabata, Toyokazu; Shiratsuyu, Kosuke; Nada, Kazushige; Takagi, Hiroshi

2012-09-01

7

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

E-print Network

# Springer Science + Business Media, LLC 2007 Abstract High density sodium lithium niobate lead free ce-free piezoelectric ceramics, hence, it is important to gain a better understanding on the dielectric and piezoelec, respectively) ceramics were prepared by the conventional mixed oxide method. High purity powders were weighted

Cao, Wenwu

8

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

9

Piezoelectric Properties of LiSbO3-Modified (K0.48Na0.52)NbO3 Lead-Free Ceramics  

NASA Astrophysics Data System (ADS)

Lead-free piezoelectric (1-x)(K0.48Na0.52)NbO3-xLiSbO3 [(1-x)KNN-xLS] ceramics were prepared by conventional sintering. A morphotropic phase boundary (MPB) between the orthorhombic and tetragonal phases was identified in the composition range of 0.04ceramics near the MPB exhibit a strong compositional dependence, and good piezoelectric properties, temperature stability, and aging characteristics. It was found that the samples with 5 mol % LS exhibited enhanced electrical properties (d33 262 pC/N, kp 46%, Tc 373 C, To--t 60 C). These results show that (1-x)KNN-xLS ceramic is a promising lead-free piezoelectric material.

Wu, Jiagang; Wang, Yuanyu; Xiao, Dingquan; Zhu, Jianguo; Yu, Ping; Wu, Lang; Wu, Wenjuan

2007-11-01

10

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

PubMed

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

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

2014-02-01

11

Lead-free multilayer piezoelectric transformer.  

PubMed

In this article, a multilayer piezoelectric transformer based on lead-free Mn-doped 0.94(Bi(12)Na(12))TiO(3)-0.06BaTiO(3) ceramics is presented. This piezoelectric transformer, with a multilayered construction in the thickness direction, is 8.3 mm long, 8.3 mm wide, and 2.3 mm thick. It operates in the second thickness extensional vibration mode. For a temperature rise of 20 degrees C, the transformer has an output power of >0.3 W. With a matching load resistance of 10 Omega, 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. PMID:17503954

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

2007-01-01

12

Fabrication of high-power piezoelectric transformers using lead-free ceramics for application in electronic ballasts.  

PubMed

CuO is doped into (Na(0.5)K(0.5))NbO(3) (NKN) ceramics to improve the piezoelectric properties and thus obtain a piezoelectric transformer (PT) with high output power. In X-ray diffraction patterns, the diffraction angles of the CuO-doped NKN ceramics shift to lower values because of an expansion of the lattice volume, thus inducing oxygen vacancies and enhancing the mechanical quality factor. A homogeneous microstructure is obtained when NKN is subjected to CuO doping, leading to improved electrical properties. PTs with different electrode areas are fabricated using the CuO-doped NKN ceramics. Considering the efficiency, voltage gain, and temperature rise of PTs at a load resistance of 1 k?, PTs with an electrode with an inner diameter of 15 mm are combined with the circuit design for driving a 13-W T5 fluorescent lamp. A temperature rise of 6C and a total efficiency of 82.4% (PT and circuit) are obtained using the present PTs. PMID:23357915

Yang, Song-Ling; Chen, Shih-Ming; Tsai, Cheng-Che; Hong, Cheng-Shong; Chu, Sheng-Yuan

2013-02-01

13

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

14

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

NASA Astrophysics Data System (ADS)

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

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

2012-04-01

15

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

16

Fabrication of Lead-Free Lithium-Doped Na0.5K0.5NbO3 Piezoelectric Ceramics with Dense Grain Structure Using Sol-Gel Surface Coating  

NASA Astrophysics Data System (ADS)

Lead-free piezoelectric 0.06(LiNbO3)-0.94(Na0.5K0.5)NbO3 (LNKN) ceramics in disc form were fabricated and characterized to acquire good electromechanical properties. A molding method including cold isostatic pressing (CIP) was used to form a dense and regular microstructure and suppress the cracking problems of LNKN ceramics during the following high-temperature sintering. The LNKN ceramic sintered at 1040 C showed a high piezoelectric constant d33 of 170 pC/N owing to its high density. Furthermore, perovskite LNKN films with the same composition as the ceramics were fabricated using 2-methoxyethanol-based sol-gel solution. The sol-gel surface coating on the LNKN ceramics was found to be very effective for increasing the piezoelectric constant because of the interface stabilization effect leading to a uniform electric field in piezoelectric elements. As a result, we obtained the highest piezoelectric constant d33 of 183 pC/N. The lead-free LNKN ceramics are promising for applications in eco-friendly ferroelectric and piezoelectric devices.

Lim, Sun Kyung; Han, Jeong Seon; Yoo, Ae Ri; Lee, Seong Eui; Lee, Hee Chul

2013-10-01

17

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

18

Effect of domain structure on the mechanical and piezoelectric properties of lead-free alkali niobate ceramics  

NASA Astrophysics Data System (ADS)

Load-bearing applications, such as actuators, require sufficient mechanical properties to guarantee long lifetime and reliability. Lead zirconate titanate (PZT) ceramics show relatively low mechanical strength which decreases after applying an electric field. Thus far, evaluations of the mechanical properties have not been the focus in the case of alkali niobate-based (NKN) ceramics. For this purpose, differently poled Lix(Na0.5K0.5)1-xNbO3 ceramics have been observed by means of 3-point bending tests. Best results were achieved with Li0.02Na0.49K0.49NbO3, with a flexural strength of 115 MPa in unpoled state. This value was maximized at a 90 domain switching fraction ? of about 20% to 134 MPa. Other compositions showed similar behavior, which led to the idea that domain switching can be used to enhance the mechanical properties of NKN ceramics. Internal stresses induced via domain reorientation might be the cause of this phenomenon and will be examined in this study.

Martin, Alexander; Kakimoto, Ken-ichi

2014-09-01

19

Preparation and characterization of Mn-doped Li0.06(Na0.5K0.5)0.94NbO3 lead-free piezoelectric ceramics with surface sol-gel coatings  

NASA Astrophysics Data System (ADS)

This study investigated the effects of Mn doping and sol-gel surface coating on the structural and the electrical properties of lead-free Li0.06(Na0.5K0.5)0.94NbO3(LNKN) ceramics in disc form for use as eco-friendly piezoelectric devices. The 1-mol% Mn-doped LNKN ceramic showed a relatively high piezoelectric constant owing to its high density in the case of its being annealed at a temperature of 1010 C. A Mn-doped LNKN sol-gel solution with the same composition as that of the ceramics was spin-coated and sintered on both sides of the ceramic surfaces to acquire improved electrical properties. The sol-gel surface coating could play a decisive role in filling the pores, resulting in flat and stable interfaces between the electrodes and the piezoelectric elements. As a result, the highest piezoelectric constant, d33, of 173 pC/N could be obtained for the Mn-doped LNKN ceramics with 420-nm-thick sol-gel surface coatings.

Yoo, Ae Ri; Lee, Seong Eui; Lee, Hee Chul

2014-08-01

20

A lead-free piezoelectric transformer in radial vibration modes.  

PubMed

In this study, a disk-shaped piezoelectric transformer was fabricated using lead-free (K,Na)NbO(3)-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 34.2 mm and thickness of 1.9 mm were measured. For a temperature rise of 35 degrees C, the transformer has a maximum output power of 12 W. 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. PMID:17411212

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

2007-03-01

21

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

22

Improved temperature stability of CaTiO{sub 3}-modified [(K{sub 0.5}Na{sub 0.5}){sub 0.96}Li{sub 0.04}](Nb{sub 0.91}Sb{sub 0.05}Ta{sub 0.04})O{sub 3} lead-free piezoelectric ceramics  

SciTech Connect

The CaTiO{sub 3}-modified [(K{sub 0.5}Na{sub 0.5}){sub 0.96}Li{sub 0.04}](Nb{sub 0.91}Sb{sub 0.05}Ta{sub 0.04})O{sub 3} lead-free piezoelectric ceramics were prepared using normal sintering for improving the temperature stability of (K{sub 0.5}Na{sub 0.5})NbO{sub 3}-based ceramics. The effects of the CaTiO{sub 3} on the temperature stability and piezoelectric properties of the ceramics were systematically studied. These results show that the CaTiO{sub 3}-modified [(K{sub 0.5}Na{sub 0.5}){sub 0.96}Li{sub 0.04}](Nb{sub 0.91}Sb{sub 0.05}Ta{sub 0.04})O{sub 3} lead-free piezoelectric ceramics possess good temperature stability in the polymorphic phase transition below room temperature, and also exhibit high piezoelectric properties (d{sub 33}=263 pC/N and k{sub p}=50%) when the ceramics were poled at an optimum poling temperature. These results indicate that the ceramic is a promising candidate material for lead-free piezoelectric ceramics.

Wu Jiagang; Xiao Dingquan; Wu Wenjuan; Zhang Bin; Zhu Jianguo [Department of Materials Science, Sichuan University, Chengdu 610064 (China); Wang Yuanyu [Department of Materials Science, Sichuan University, Chengdu 610064 (China); College of Materials Science and Metallurgy Engineering, Guizhou University, Guiyang 550003 (China)

2008-07-15

23

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

PubMed Central

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

2012-01-01

24

Diffuse phase transition and electrical properties of lead-free piezoelectric (LixNa1-x)NbO3 (0.04 ? x ? 0.20) ceramics near morphotropic phase boundary  

NASA Astrophysics Data System (ADS)

Temperature-dependent dielectric permittivity of lead-free (LixNa1-x)NbO3 for nominal x = 0.04-0.20, prepared by solid state reaction followed by sintering, was studied to resolve often debated issue pertaining to exactness of morphotropic phase boundary (MPB) location besides structural aspects and phase stability in the system near MPB. Interestingly, a diffuse phase transition has been observed in the dielectric permittivity peak arising from the disorder induced in A-site and structural frustration in the perovskite cell due to Li substitution. A partial phase diagram has been proposed based on temperature-dependent dielectric permittivity studies. The room temperature piezoelectric and ferroelectric properties were investigated and the ceramics with x = 0.12 showed relatively good electrical properties (d33 = 28 pC/N, kp = 13.8%, Qm = 440, Pr = 12.5 ?C/cm2, Ec = 43.2 kV/cm, and Tm = 340 C). These parameter values make this material suitable for piezoelectric resonator and filter applications. Moreover, a high dielectric permittivity (?'r = 2703) with broad diffuse peak near transition temperature, and low dielectric loss (<4%) over a wide temperature range (50-250 C) found in this material may also have a potential application in high-temperature multilayer capacitors in automotive and aerospace related industries.

Mitra, S.; Kulkarni, A. R.; Prakash, Om

2013-08-01

25

High Performance Lead-free Piezoelectric Ceramics in the (K,Na)NbO3-LiTaO3 Solid Solution System  

Microsoft Academic Search

A new solid solution system, namely {(K0.5Na0.5)1? xLix}(Nb1? yTay)O3, with full density, a large piezoelectric constant and high stability has been developed. The system has a morphotropic phase boundary (MPB) between orthorhombic and tetragonal. The MPB gives the largest piezoelectric d constant at {(K0.5Na0.5)0.97Li0.03}(Nb0.8Ta0.2)O3, which exhibits a piezoelectric actuator constant d33 of 230 pm\\/V, 2.34 times that of pure (K0.5Na0.5)NbO3

Yasuyoshi Saito; Hisaaki Takao

2006-01-01

26

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

NASA Astrophysics Data System (ADS)

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

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

2013-04-01

27

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

28

Journal of Crystal Growth 281 (2005) 364369 Flux growth and characterization of lead-free piezoelectric  

E-print Network

-free piezoelectric single crystal [Bi0.5(Na1?xKx)0.5]TiO3 Xiujie Yia,b , Huanchu Chena,?, Wenwu Caoc , Minglei Zhaod Available online 13 June 2005 Communicated by M. Schieber Abstract Lead-free piezoelectric single crystal melting during growth. Superior piezoelectric and electromechanical properties were found in these lead

Cao, Wenwu

29

Dielectric and piezoelectric properties of Y{sub 2}O{sub 3} doped (Bi{sub 0.5}Na{sub 0.5}){sub 0.94}Ba{sub 0.06}TiO{sub 3} lead-free piezoelectric ceramics  

SciTech Connect

Y{sub 2}O{sub 3} doped lead-free piezoelectric ceramics (Bi{sub 0.5}Na{sub 0.5}){sub 0.94}Ba{sub 0.06}TiO{sub 3} (0-0.7 wt%) were synthesized by the conventional solid state reaction method, and the effect of Y{sub 2}O{sub 3} addition on the structure and electrical properties was investigated. X-ray diffraction shows that Y{sub 2}O{sub 3} diffuses into the lattice of (Bi{sub 0.5}Na{sub 0.5}){sub 0.94}Ba{sub 0.06}TiO{sub 3} to form a solid solution with a pure perovskite structure. The temperature dependence of dielectric constant of Y{sub 2}O{sub 3} doped samples under various frequencies indicates obvious relaxor characteristics different from typical relaxor ferroelectric and the mechanism of the relaxor behavior was discussed. The optimum piezoelectric properties of piezoelectric constant d{sub 33} = 137 pC/N and the electromechanical coupling factor k{sub p} = 0.30 are obtained at 0.5% and 0.1% Y{sub 2}O{sub 3} addition, respectively.

Zhou Changrong [Department of Information Material Science and Engineering, Guilin University of Electronic Technology, Guilin, Guangxi 541004 (China)], E-mail: zcr750320@yahoo.com.cn; Liu Xinyu [Department of Information Material Science and Engineering, Guilin University of Electronic Technology, Guilin, Guangxi 541004 (China); Li Weizhou [School of Resources and Environments, Guangxi University, Nanning, Guangxi 530004 (China); Yuan Changlai [Department of Information Material Science and Engineering, Guilin University of Electronic Technology, Guilin, Guangxi 541004 (China)

2009-04-02

30

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

E-print Network

parallel layers are used to computationally reconstruct three-dimensional samples, simulate the local chemistries [1­3]. Lead-free reports have emerged for applications that range from actuators [4], to force form. Indeed, crystallographic texture engineering has demonstrated that by start- ing from plate

Rohrer, Gregory S.

31

A lead-free flexible structure for piezoelectric power generation  

NASA Astrophysics Data System (ADS)

Here, we demonstrate a fully-flexible piezoelectric hybrid structure composed of sodium niobate nanocubes and polyvinylidene fluoride. Hydrothermally-grown sodium niobate nanocubes show an orthorhombic crystal structure with Pmc21 symmetry, and polyvinylidene fluoride is electrically poled for the ?-phase, each of those represents piezoelectricity. Hybrid devices were electrically tested in two different modes by applying forces parallel to the in-plane and the out-of-plane directions of the piezoelectric layer. Our device shows an output voltage, current, and power density of 2.9 V, 68 nA, and 4.4 ?Wcm-3, respectively, at a pushing force of 5 kgf and a frequency of 1 Hz. The output power generation also shows a linear relation with the applied force over a wide range of 1-5 kgf. This implies our flexible hybrid piezoelectric structure can be adapted to various mechanical environments. Our unique structure should open up various application areas of piezoelectric materials such as touch sensors, flexible energy harvesters and eco-friendly piezoelectric actuators.

Kho, Byung Woo; Yun, Byung Kil; Jung, Jong Hoon; Lee, Minbaek

2014-06-01

32

Structural And Electrical Analysis Of Lead Free BZT-xBCT Ceramics  

SciTech Connect

A comparative study of structural and electric properties of a recently discovered lead free electroceramic, Ba(Zr{sub 0.2}Ti{sub 0.8})O{sub 3}-x(Ba{sub 0.7}Ca{sub 0.3})TiO{sub 3} or BZT-xBCT, was conducted in the entire range from x = 0 to x = 1. This novel ceramic composite is being seen as a genuine understudy for commercially one of the most widely used piezoelectric ceramic, PZT, which is facing worldwide criticism due to its lead toxicity. The new system can be very extensively used like PZT in transduction applications as sensor, actuator and ultrasonic devices apart from numerous other utilities. The XRD, SEM and Ferroelectric studies establish the structural transition and different phases as function of Zr /Ti and Ba /Ca ratios.

Bhardwaj, Chandan; Kumar, Ashvani; Kaur, Davinder [Functional Nanomaterials Research Lab, Department of Physics and Centre of Nanotechnology, Indian Institute of Technology Roorkee, Roorkee 247667 (India)

2010-12-01

33

Structural And Electrical Analysis Of Lead Free BZT-xBCT Ceramics  

NASA Astrophysics Data System (ADS)

A comparative study of structural and electric properties of a recently discovered lead free electroceramic, Ba(Zr0.2Ti0.8)O3-x(Ba0.7Ca0.3)TiO3 or BZT-xBCT, was conducted in the entire range from x = 0 to x = 1. This novel ceramic composite is being seen as a genuine understudy for commercially one of the most widely used piezoelectric ceramic, PZT, which is facing worldwide criticism due to its lead toxicity. The new system can be very extensively used like PZT in transduction applications as sensor, actuator and ultrasonic devices apart from numerous other utilities. The XRD, SEM and Ferroelectric studies establish the structural transition and different phases as function of Zr /Ti and Ba /Ca ratios.

Bhardwaj, Chandan; Kumar, Ashvani; Kaur, Davinder

2010-12-01

34

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

PubMed

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

Aksel, Elena; Jones, Jacob L

2010-01-01

35

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

36

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

37

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

PubMed Central

Lead-free 0.98(Na0.5K0.5)NbO3-0.02Ba(Zr0.52Ti0.48)O3 [0.98NKN-0.02BZT] ceramics were fabricated by the conventional mixed oxide method with sintering temperature at 1,080C to 1,120C. The results indicate that the sintering temperature obviously influences the structural and electrical properties of the sample. For the 0.98NKN-0.02BZT ceramics sintered at 1,080C to 1,120C, the bulk density increased with increasing sintering temperature and showed a maximum value at a sintering temperature of 1,090C. The dielectric constant, piezoelectric constant [d33], electromechanical coupling coefficient [kp], and remnant polarization [Pr] increased with increasing sintering temperature, which might be related to the increase in the relative density. However, the samples would be deteriorated when they are sintered above the optimum temperature. High piezoelectric properties of d33 = 217 pC/N, kp = 41%, dielectric constant = 1,951, and ferroelectric properties of Pr = 10.3 ?C/cm2 were obtained for the 0.98NKN-0.02BZT ceramics sintered at 1,090C for 4 h. PMID:22221445

2012-01-01

38

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

39

HF MODELING FOR THE ELECTRICAL PROPERTY DETERMINATION OF A LEAD-FREE PIEZOELECTRIC MATERIAL  

Microsoft Academic Search

An electric properties analysis of a lead-free piezoelectric material was performed in this paper. The material is a solid solution perovskite type: (1 ? x)Na1\\/2Bi1\\/2TiO3-xBaTiO3 (NBT- BTx), with x = 0.11. Electrical effective permittivity was determined and this quantity resonant behavior was drawn, in the frequency domain of 0.3-9.8 GHz. The method of analysis is based on structure simulations, with

I. B. CIOBANU; D. IONESCU

2009-01-01

40

Disc piezoelectric ceramic transformers.  

PubMed

In this contribution, we present our study on disc-shaped and homogeneously poled piezoelectric ceramic transformers working in planar-extensional vibration modes. Transformers are designed with electrodes divided into wedge, axisymmetrical ring-dot, moonie, smile, or yin-yang segments. Transformation ratio, efficiency, and input and output impedances were measured for low-power signals. Transformer efficiency and transformation ratio were measured as a function of frequency and impedance load in the secondary circuit. Optimum impedance for the maximum efficiency has been found. Maximum efficiency and no-load transformation ratio can reach almost 100% and 52 for the fundamental resonance of ring-dot transformers and 98% and 67 for the second resonance of 2-segment wedge transformers. Maximum efficiency was reached at optimum impedance, which is in the range from 500 ? to 10 k?, depending on the electrode pattern and size. Fundamental vibration mode and its overtones were further studied using frequency-modulated digital holographic interferometry and by the finite element method. Complementary information has been obtained by the infrared camera visualization of surface temperature profiles at higher driving power. PMID:25004532

Erhart, Jiri; P?lpn, Petr; Dole?ek, Roman; Psota, Pavel; Ldl, Vt

2013-08-01

41

Cite this: CrystEngComm, 2013, 15, Large size lead-free (Na,K)(Nb,Ta)O3 piezoelectric single  

E-print Network

Cite this: CrystEngComm, 2013, 15, 7718 Large size lead-free (Na,K)(Nb,Ta)O3 piezoelectric single Jiangb and Wenwu Cao*ab Environmental friendly piezoelectric single crystal, Ta-modified (K,Na)NbO3 enhance its piezoelectric properties. In addition, a self-consistent complete set of elastic, dielectric

Cao, Wenwu

42

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

43

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.

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

2014-01-01

44

Enhancement of Q(m) by co-doping of Li and Cu to potassium sodium niobate lead-free ceramics.  

PubMed

Lead-free piezoelectric ceramics KNN modified by Li-substitution and CuO addition have been synthesized, and the piezoelectric and dielectric properties were measured. A morphotropic phase boundary (MPB) between orthorhombic and tetragonal phases was formed with Li-substitution. The co doping of Li and Cu markedly enhanced the mechanical quality factor (Q(m)) in comparison with the sole doping of Li and Cu. Anomalous anti ferroelectric-like hysteresis curves were observed in 2 mol% CuO-doped ceramics. The anti-ferroelectric-like curves were changed to that of normal ferroelectrics following poling. A model based on the formation of the internal bias field (Ei) due to the movements of space charges was proposed to explain these phenomena. It was considered that the Ei stabilized the spontaneous polarization (Ps) and suppressed the domain wall motion to enhance the Q(m). The highest Qm obtained in this study was 742. The [(Na0(0.5)K0(0.5))(0.96)Li0(0.04) ] NbO(3) + 0.45 mol% CuO ceramics showed a high Q(m) value of 414 with a high piezoelectric constant d(33) of 100 pC/N. PMID:18519199

Li, E; Kakemoto, H; Wada, S; Tsurumi, T

2008-05-01

45

Compositional dependence of phase structure and electrical properties in (K0.42Na0.58)NbO3-LiSbO3 lead-free ceramics  

NASA Astrophysics Data System (ADS)

(1-x)(K0.42Na0.58)NbO3-xLiSbO3 [(1-x)KNN-xLS] lead-free piezoelectric ceramics were prepared by the conventional mixed oxide method. The compositional dependence of the phase structure and the electrical properties of the ceramics were studied. A morphotropic phase boundary (MPB) between the orthorhombic and tetragonal phases was identified in the composition range of 0.04ceramics near the MPB exhibit a strong compositional dependence and enhanced piezoelectric properties. The ceramics with 5 mol. % LS exhibit enhanced electrical properties (d33270 pC/N, kp47.2%, Tc364 C , To-t=35 C, ?r1412, tan ? 2.8%, and Pr25.7 ?C/cm2; Ec11.1 kV/cm) and possess low dielectric loss (<2%) at 10 and 100 kHz at high temperature (250-400 C). The low dielectric loss at high temperature is very important for high-temperature application of the ceramics. The related mechanism of the enhanced electrical properties of the ceramics was also discussed. These results show that (1-x)KNN-xLS (x =0.05) ceramic is a promising lead-free piezoelectric material.

Wu, Jiagang; Xiao, Dingquan; Wang, Yuanyu; Zhu, Jianguo; Yu, Ping; Jiang, Yihang

2007-12-01

46

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

47

Lead-Free Piezoelectric MEMS Energy Harvesters of (K,Na)NbO3 Thin Films on Stainless Steel Cantilevers  

NASA Astrophysics Data System (ADS)

We fabricated piezoelectric MEMS energy harvesters (EHs) of lead-free (K,Na)NbO3 (KNN) thin films on microfabricated stainless steel cantilevers. The use of metal substrates makes it possible to fabricate thin cantilevers owing to a large fracture toughness compared with Si substrates. KNN films were directly deposited onto Pt-coated stainless steel cantilevers by rf-magnetron sputtering, thereby simplifying the fabrication process of the EHs. From XRD measurement, we confirmed that the KNN films on Pt-coated stainless steel cantilevers had a perovskite structure with a preferential (001) orientation. The transverse piezoelectric coefficient e31f and relative dielectric constant ?r were measured to be -3.8 C/m2 and 409, respectively. From the evaluation of the power generation performance of a KNN thin-film EH (length: 7.5 mm, width: 5.0 mm, weight of tip mass: 25 mg), we obtained a large average output power of 1.6 W under vibration at 393 Hz and 10 m/s2.

Tsujiura, Yuichi; Suwa, Eisaku; Kurokawa, Fumiya; Hida, Hirotaka; Suenaga, Kazufumi; Shibata, Kenji; Kanno, Isaku

2013-09-01

48

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

49

Templated Grain Growth of Textured Piezoelectric Ceramics  

Microsoft Academic Search

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

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

2004-01-01

50

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

51

Models and Characterization of Piezoelectric Ceramics  

SciTech Connect

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

Ebenezer, D. D. [Naval Physical and Oceanographic Laboratory Kochi 682021 (India)

2008-07-29

52

A study on (K, Na) NbO3 based multilayer piezoelectric ceramics micro speaker  

NASA Astrophysics Data System (ADS)

A flat panel micro speaker was fabricated from (K, Na) NbO3 (KNN)-based multilayer piezoelectric ceramics by a tape casting and cofiring process using Ag-Pd alloys as an inner electrode. The interface between ceramic and electrode was investigated by scanning electron microscope (SEM) and transmission electron microscope (TEM). The acoustic response was characterized by a standard audio test system. We found that the micro speaker with dimensions of 23 27 0.6 mm3, using three layers of 30 ?m thickness KNN-based ceramic, has a high average sound pressure level (SPL) of 87 dB, between 100 Hz-20 kHz under five voltage. This result was even better than that of lead zirconate titanate (PZT)-based ceramics under the same conditions. The experimental results show that the KNN-based multilayer ceramics could be used as lead free piezoelectric micro speakers.

Gao, Renlong; Chu, Xiangcheng; Huan, Yu; Sun, Yiming; Liu, Jiayi; Wang, Xiaohui; Li, Longtu

2014-10-01

53

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

NASA Astrophysics Data System (ADS)

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

Chauhan, Aditya; Patel, Satyanarayan; Vaish, Rahul

2014-08-01

54

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

PubMed Central

The incorporation method was employed to produce potassium sodium niobate [KNN] (K0.5Na0.5NbO3) glass ceramics from the KNN-SiO2 system. This incorporation method combines a simple mixed-oxide technique for producing KNN powder and a conventional melt-quenching technique to form the resulting glass. KNN was calcined at 800C and subsequently mixed with SiO2 in the KNN:SiO2 ratio of 75:25 (mol%). The successfully produced optically transparent glass was then subjected to a heat treatment schedule at temperatures ranging from 525C -575C for crystallization. All glass ceramics of more than 40% transmittance crystallized into KNN nanocrystals that were rectangular in shape and dispersed well throughout the glass matrix. The crystal size and crystallinity were found to increase with increasing heat treatment temperature, which in turn plays an important role in controlling the properties of the glass ceramics, including physical, optical, and dielectric properties. The transparency of the glass samples decreased with increasing crystal size. The maximum room temperature dielectric constant (?r) was as high as 474 at 10 kHz with an acceptable low loss (tan?) around 0.02 at 10 kHz. PMID:22340426

2012-01-01

55

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

56

Piezoelectric ceramics and composites via rapid prototyping techniques  

Microsoft Academic Search

Reviews the inherent advantages, i.e. design flexibility and processing, of manufacturing piezoelectric ceramics and composites with numerous architectures via rapid prototyping techniques. Reports on processing in which piezoelectric ceramics and composites with novel and conventional designs were fabricated using rapid prototyping techniques. Fused deposition of ceramics, fused deposition modeling, and Sanders prototyping techniques were used to fabricate lead-zirconate-titanate ceramics and

A. Bandyopadhyay; R. K. Panda; T. F. McNulty; F. Mohammadi; S. C. Danforth; A. Safari

1998-01-01

57

Piezoelectric ceramic implants: in vivo results.  

PubMed

The suitability of barium titanate (BaTiO3) ceramic for direct substitution of hard tissues was evaluated using both electrically stimulated (piezoelectric) and inactive (nonpolarized) test implants. Textured cylindrical specimens, half of them made piezoelectric by polarization in a high electric field, were implanted into the cortex of the midshaft region of the femora of dogs for various periods of time. Interfacial healing and bio-compatibility of the implant material were studied using mechanical, microradiographical, and histological techniques. Our results indicate that barium titanate ceramic shows a very high degree of biocompatibility as evidenced by the absence of inflammatory or foreign body reactions at the implant-tissue interface. Furthermore, the material and its surface porosity allowed a high degree of bone ingrowth as evidenced by microradiography and a high degree of interfacial tensile strength. No difference was found between the piezoelectric and the electrically neutral implant-tissue interfaces. Possible reasons for this are discussed. The excellent mechanical properties of barium titanate, its superior biocompatibility, and the ability of bone to form a strong mechanical interfacial bond with it, makes this material a new candidate for further tests for hard tissue replacement. PMID:7348700

Park, J B; Kelly, B J; Kenner, G H; von Recum, A F; Grether, M F; Coffeen, W W

1981-01-01

58

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

59

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

NASA Astrophysics Data System (ADS)

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

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

2011-05-01

60

Effects of K/Na ratio on the phase structure and electrical properties of (K{sub x}Na{sub 0.96-x}Li{sub 0.04})(Nb{sub 0.91}Ta{sub 0.05}Sb{sub 0.04})O{sub 3} lead-free ceramics  

SciTech Connect

(K{sub x}Na{sub 0.96-x}Li{sub 0.04})(Nb{sub 0.91}Ta{sub 0.05}Sb{sub 0.04})O{sub 3} (x=0.32-0.56) lead-free piezoelectric ceramics were prepared by conventional sintering. The effects of K/Na ratio on the phase structure and electrical properties of the ceramics were studied. These results indicate that the phase structure undergoes a transition from orthorhombic to tetragonal phase with increase of x. The ceramics with x=0.38 exhibit enhanced electrical properties (d{sub 33}{approx}306 pC/N; k{sub p}{approx}48%; k{sub t}{approx}49%; T{sub c}{approx}337 deg. C; {epsilon}{sub r}{approx}1327; tan {delta}{approx}2.5%; P{sub r}{approx}34.9 {mu}C/cm{sup 2}; E{sub c}{approx}11.3 kV/cm). Enhanced electrical properties of the ceramics should be attributed to the polymorphic phase transition near room temperature. These results show that the ceramic with x=0.38 is a promising lead-free piezoelectric material.

Wu Jiagang; Xiao Dingquan; Wang Yuanyu; Zhu Jianguo; Wu Lang; Jiang Yihang [Department of Materials Science, Sichuan University, Chengdu 610064 (China); Department of Materials Science, Sichuan University, Chengdu 610064 (China) and College of Materials Science and Metallurgy Engineering; Guizhou University, Guizhou 550003 (China); Department of Materials Science, Sichuan University, Chengdu 610064 (China)

2007-12-17

61

Development of novel piezoelectric ceramics and composites for transducer applications  

Microsoft Academic Search

Over the last decade, several methods were utilized to develop novel piezoelectric ceramic\\/polymer composites for transducer applications. Solid freeform fabrication (SFF) is one of the methods that have been emphasized recently. SFF techniques have been used to fabricate polymer, metal or ceramic structures on a fixtureless platform, directly from a computer aided design file. During design verification or the product

Ahmad Safari; Stephen C. Danforth

1998-01-01

62

Piezoelectric lead zirconate titanate ceramic fiber\\/polymer composites  

Microsoft Academic Search

This papers on piezoelectric lead zirconate titanate (PZT) ceramic fiber\\/polymer composite were fabricated by a novel technique referred to as relic processing. Basically, this involved impregnating a woven carbon-fiber template material with PZT precursor by soaking the template in a PZT stock solution. Careful heat treatment pyrolized the carbon, resulting in a PZT ceramic relic that retained the fibrous template

David J. Waller; P. Safari

1992-01-01

63

Identicalness between Piezoelectric Loss and Dielectric Loss in Converse Effect of Piezoelectric Ceramic Resonators  

NASA Astrophysics Data System (ADS)

The relationship between piezoelectric loss (tan ?P) and dielectric loss (tan ?E) in the converse piezoelectric effect in piezoelectric ceramics was investigated theoretically and experimentally. The theoretical consideration was based on the assumption that strain should be proportional to polarization without phase delay in both the intrinsic contribution due to lattice deformation and the extrinsic contribution due to domain wall motion. It was expected that the piezoelectric loss in the converse piezoelectric effect should be identical to the dielectric loss. In order to experimentally verify the identicalness between the losses, the immittance curves of the piezoelectric response of various Pb(Zr,Ti)O3-based ceramic resonators were fitted if the piezoelectric loss tan ?P (1) is equal to zero, (2) exists as the independent variable, and (3) is the same as the dielectric loss tan ?E. The observation result clearly proved that tan ?P is identical to tan ?E. This identicalness was also demonstrated by analyzing the phase angle of vibration velocity in mechanical response.

Hagiwara, Manabu; Hoshina, Takuya; Takeda, Hiroaki; Tsurumi, Takaaki

2012-09-01

64

Thickness-shear approximation for piezoelectric ceramic plates  

Microsoft Academic Search

The thickness-shear mode in piezoelectric ceramic plates has been analysed theoretically with the approximate two-dimensional plate theory. The theoretical dispersion for a fully electroded infinite plate has been compared with experimental results on rectangular plate resonators. Limits of the application of the thickness-shear approximation related to the plate geometry have been established.

V. L. STRASHILOV; M. M. NADOLIISKI

1989-01-01

65

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

NASA Astrophysics Data System (ADS)

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

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

2014-07-01

66

Realization of high-energy density polycrystalline piezoelectric ceramics  

SciTech Connect

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

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

2006-01-16

67

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

Microsoft Academic Search

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

I. Patel; E. Siores; T. Shah

2010-01-01

68

Application of Bare Piezoelectric Ceramics in Monitoring Resin Transfer Moulding (RTM) Process  

E-print Network

This paper investigates application of piezoelectric ceramics mounted on surface of mould to monitor flow front and curing phases of resin in Resin Transfer Moulding (RTM) process. The piezoelectric ceramic is used for both generating ultrasound and measuring energy of echoed ultrasonic wave at the interface of mould and resin. One of the advantages of this method is that the piezoelectric ceramic can be integrated with electronic circuits in one package, including pulser, signal conditioning, data processing and communication circuits, to make a miniaturized smart sensor. A cost-effective monitoring system can be built by employing the integrated sensors. An experimental system comprising pulse generation circuitry for driving piezoelectric ceramic and ultrasonic energy measurement circuitry has been built and used in proof of concept experiments. Results of the experiments show effectiveness of bare piezoelectric ceramics in monitoring flow front of resin and curing phases of resin during an RTM process.

unknown authors

69

Measurement of Micro Vibration of Car by Piezoelectric Ceramics  

NASA Astrophysics Data System (ADS)

Recently, there are various accidents and crimes related to the car. In some cases, the accidents and the crimes can be prevented if it is possible to detect a human who is in the car. For example, we can prevent a baby who is left in a car under the hot weather from dehydration or death occurred by heat inside disease. In another case, it is estimated that the United States currently has as many as 12 million illegal immigrants. In order to prevent further influx of illegal immigrants, the police are physically searching incoming vehicles at national boundaries aiming at finding those who are hiding inside. However, the physical inspections require much manpower cost and time. An inspection method to see inside the vehicles through X-ray images has also been used for this end. But the cost and the installation places are the problems of the large-scale X-ray system. Proposed in this paper is a piezoelectric ceramic system to handily measure the micro vibrations of motor vehicles. And applying the algorithm of Support Vector Machine (SVM), the existence of human body inside vehicles can be detected. The experiment was carried out using four types of vehicles: a mini car; an auto mobile; a van; and a truck weighing 1.5 tons. As the results, the correct determination ratio was 91.2% for the experiment with the piezoelectric ceramic under the front wheels and 97.0% under the rear wheels, when the vehicle used for the examination had also been used together with other three types of vehicles to obtain SVM training data. When the vehicle used for the examination had not been used together with the other three to obtain SVM training data, on the other hand, the correct determination ratio was 93.7% for the experiment with the piezoelectric ceramic under the front wheels and 95.7% under the rear wheels.

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

70

Origin of high piezoelectric response in A-site disordered morphotropic phase boundary composition of lead-free piezoelectric 0.93(Na0.5Bi0.5)TiO3-0.07BaTiO3  

NASA Astrophysics Data System (ADS)

Perovskite piezoelectric compositions near the morphotropic phase boundary (MPB) are known to exhibit high piezoelectric response. In lead-based ABO3 compound with B-site disorder, the origin of this enhancement has been associated with the presence of an intermediate monoclinic/orthorhombic state that bridges the adjacent ferroelectric rhombohedral and tetragonal phases. However, the origin of high piezoelectric response in lead-free ABO3 compounds with A-site disorder has not been conclusively established. We describe a microscopic model derived from comparative analyses of high resolution transmission electron microscopy and neutron diffraction that explains the origin of high piezoelectric response in lead-free MPB compositions of 0.93(Na0.5Bi0.5)TiO3-0.07BaTiO3. Direct observation of nanotwins with monoclinic symmetry confirmed the presence of an intermediate bridging phase that facilitates a pathway for polarization reorientation. Monoclinic distortions of an average rhombohedral phase are attributed to localized displacements of atoms along the non-polar directions.

Maurya, Deepam; Murayama, M.; Pramanick, A.; Reynolds, W. T.; An, Ke; Priya, Shashank

2013-03-01

71

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

NASA Astrophysics Data System (ADS)

A three-dimensional (3-D) molding process using a master polymer mold produced by microstereolithography has been developed for the production of piezoelectric ceramic elements. In this method, ceramic slurry is injected into a 3-D polymer mold via a centrifugal casting process. The polymer master mold is thermally decomposed so that complex 3-D piezoelectric ceramic elements can be produced. As an example of 3-D piezoelectric ceramic elements, we produced a spiral piezoelectric element that can convert multidirectional loads into a voltage. It was confirmed that a prototype of the spiral piezoelectric element could generate a voltage by applying a load in both parallel and lateral directions in relation to the helical axis. The power output of 123 pW was obtained by applying the maximum load of 2.8N at 2 Hz along the helical axis. In addition, to improve the performance of power generation, we utilized a two-step sintering process to obtain dense piezoelectric elements. As a result, we obtained a sintering body with relative density of 92.8%. Piezoelectric constant d31 of the sintered body attained to -40.0 pC/N. Furthermore we analyzed the open-circuit voltage of the spiral piezoelectric element using COMSOL multiphysics. As a result, it was found that use of patterned electrodes according to the surface potential distribution of the spiral piezoelectric element had a potential to provide high output voltage that was 20 times larger than that of uniform electrodes.

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

2014-03-01

72

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

NASA Technical Reports Server (NTRS)

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

Bryant, Robert G.

2007-01-01

73

On saturation-strip model of a permeable crack in a piezoelectric ceramic  

E-print Network

and Sun [12] show that there is a decrease in the critical stress of a cracked piezoelectric body. This contribution elucidates how an applied electric field affects crack growth in piezoelectric ceramic through its if the electric field is applied along the direction of poling axis, and there is an increase in critical stress

Li, Shaofan

74

Observation of piezoelectric resonance in time domain transient current of ferroelectric ceramics and crystals  

Microsoft Academic Search

An abnormal resonance behavior was observed from the transient current in the time domain for both ferroelectric ceramics and single crystals excited with a stepwise electric field. The phenomenon can be accounted for as piezoelectric resonance. Corresponding resonant peaks in the frequency spectrum of impedance verified the piezoelectric origin of the abnormal resonance. Using a RLC series equivalent circuit of

Li Jin; Xi Yao; Xiaoyong Wei; Zengzhe Xi

2005-01-01

75

Domain orientation and piezoelectric properties of Ag doped PMN-PZT ceramics  

Microsoft Academic Search

The hysteresis, dielectric, and piezoelectric properties of ternary 0.5PMN-0.5-PZT (lead magnesium niobate-lead zirconate titanate) ceramics with Ag substitution are described. These ceramics show good square hysteresis loops and thus are promising for thin-film memory applications. At high Ag concentrations the dielectric loss decreased, indicating an increase in the ordering of the structure. A marked increase in the piezoelectric properties, particularly

K. V. R. Murty; S. N. Murty; K. C. Mouli; A. Bhanumathi

1992-01-01

76

Long ranged structural modulation in the pre-morphotropic phase boundary cubic-like state of the lead-free piezoelectric Na{sub 1/2}Bi{sub 1/2}TiO{sub 3}-BaTiO{sub 3}  

SciTech Connect

The nature of the pre-morphotropic phase boundary (MPB) cubic-like state in the lead-free piezoelectric ceramics (1?x)Na{sub 1/2}Bi{sub 1/2}TiO{sub 3}-(x)BaTiO{sub 3} at x???0.06 has been examined in detail by electric field and temperature dependent neutron diffraction, x-ray diffraction, dielectric and ferroelectric characterization. The superlattice reflections in the neutron diffraction patterns cannot be explained with the tetragonal P4bm and the rhombohedral (R3c) phase coexistence model. The cubic like state is rather a result of long ranged modulated complex octahedral tilt. This modulated structure exhibits anomalously large dielectric dispersion. The modulated structure transforms to a MPB state on poling. The field-stabilized MPB state is destroyed and the modulated structure is restored on heating the poled specimen above the Vogel-Fulcher freezing temperature. The results show the predominant role of competing octahedral tilts in determining the nature of structural and polar states in Na{sub 1/2}Bi{sub 1/2}TiO{sub 3}-based ferroelectrics.

Garg, Rohini; Narayana Rao, Badari; Ranjan, Rajeev, E-mail: rajeev@materials.iisc.ernet.in [Department of Materials Engineering, Indian Institute of Science, Bangalore 560012 (India); Senyshyn, Anatoliy [Forschungsneutronenquelle Heinz Maier-Leibnitz (FRM II), Technische Universitt Mnchen, Lichtenbergestrasse 1, D-85747 Garching b. Mnchen (Germany)

2013-12-21

77

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

SciTech Connect

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

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

1997-08-01

78

Using Piezoelectric Ceramics for Dust Mitigation of Space Suits  

NASA Technical Reports Server (NTRS)

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

Angel, Heather K.

2004-01-01

79

Strong piezoelectricity exhibited by large-grained BaTiO3 ceramics  

NASA Astrophysics Data System (ADS)

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

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

2014-06-01

80

JOURNAL DE PHYSIQUE Colloque C2, suppliment au no 4, Tome 33, Avril 1972, page C2-243 NEW PIEZOELECTRIC CERAMICS  

E-print Network

PIEZOELECTRIC CERAMICS V. V. KLIMOV, 0. S. DIDKOVSKAJA, G. E. SAVENKOVA and Ju. N. VENEVTSEV Research Institute de leurs applications. Abstract. -New piezoelectric materials have developed on the base of the crystal chemistry conceptionsof increasingthe piezoelectric activity of solid solutions

Paris-Sud XI, Université de

81

Magnetic field sensing with a single piezoelectric ceramic disk: Experiments and modeling  

NASA Astrophysics Data System (ADS)

This study reports on the magnetoelectric coupling in a single piezoelectric ceramic disk subjected to both ac and dc magnetic fields perpendicularly applied to the sample's plane. Eddy currents are induced within the electrodes of the ceramic by ac magnetic flux via the Lenz-Faraday equation and yields Lorentz forces and stresses which are transferred to the piezoelectric ceramic. This latter transduces stress into electrical charges through electromechanical coupling in radial mode. The measured output magnetoelectric current could be successfully modeled using piezoelectric equations providing the inductively coupled voltage between the electrodes of the ceramic is taken into account. This voltage originates from the ac magnetic flux through the experimental loop, which is not a perfect short-circuit and yields two other contributions to the total current: piezoelectric current due to the induced electric field and the dielectric loop current. Radial velocity measurements confirmed the distinct contributions to the current. Thus, room temperature magnetic field detection is achievable using this single piezoelectric disk with a good sensitivity and linear response versus dc magnetic field change.

Guiffard, B.; Zhang, J.-W.; Guyomar, D.; Garbuio, L.; Cottinet, P.-J.; Belouadah, R.

2010-11-01

82

THERMAL DEGRADATION AND AGING OF HIGH TEMPERATURE PIEZOELECTRIC CERAMICS.  

E-print Network

??Piezoelectric materials have numerous applications like high temperature accelerometers, pressure, flow and NDT transducers, acoustic emission, ultrasonic cleaning, welding, high voltage generators, medical therapy etc. (more)

Gotmare, Sunil W.

2008-01-01

83

Study of barrier layer capacitance effect in lead free Ba0.95Sr0.05(Fe0.5Nb0.5)O3-BaZr0.1Ti0.9O3 ceramics  

NASA Astrophysics Data System (ADS)

Lead-free Ba0.95Sr0.05(Fe0.5Nb0.5)O3-BaZr0.1Ti0.9O3 (50/50) ceramic, a material with potential applications for energy storage, are investigated. X-ray diffraction patterns show a single phase perovskite structure in all the samples. Sintering temperature affects the microstructural and dielectric properties of the ceramics. Microstructural analysis showed the uniformly distributed and highly packed grains in all the samples. We obtained high dielectric constant with low dielectric loss due to the controlled sintering. Giant dielectric constant (~19496) with low dielectric loss (~0.32) was obtained for 1250 C sintered sample at room temperature and 1 kHz frequency. Complex impedance analysis confirms that the grain boundary effect (barrier layer formation) is responsible for such a high value of dielectric constant. Another interesting feature of this ceramic is the appearance of room temperature magnetodielectric response (1.9%, 8 kOe) at 100 Hz frequency.

Kumar Patel, Piyush; Yadav, K. L.

2014-11-01

84

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

NASA Astrophysics Data System (ADS)

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

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

2011-11-01

85

Influence of the fluoride ion on the piezoelectric properties of a pzt ceramics  

Microsoft Academic Search

In order to decrease dielectric losses of PZT type piezoelectric ceramics, it is necessary to introduce oxygen vacancies in ABO3 perovskite lattice by heterovalent cationic substitutions (for instance Fe, Mn, Ni in place of B ions). Hence, it is possible, at room temperature, to reduce the dielectric loss by an order of magnitude of corresponding stoichiometric materials. This phenomenon is

Lucien Eyraud; Paul Eyraud; David Audigier; Bernard Claudel

1996-01-01

86

Development of a Templated Grain Growth System for Texturing Piezoelectric Ceramics  

E-print Network

-crystal-like piezoelectric fibers will provide excellent components in ceramic­polymer composites. TGG offers the most and composition (Sabolsky et al., 2001). However, the costs of both routes remain high, and the geometries economical path to such fibers. When incorporated into a 3-1 polymer composite with interdigitated electrodes

Azad, Abdul-Majeed

87

Effects of dc Electric Field on Mechanical Properties of Piezoelectric Ceramics  

Microsoft Academic Search

The effects of dc electric field on mechanical properties such as hardness, fracture toughness, flexural strength and flexural fatigue strength of piezoelectric ceramics were investigated. Hardness and fracture toughness were not influenced by the dc electric field, where as the flexural strength and the fatigue strength degraded with the absolute value of the electric field. The degradation of the flexural

Hiroaki Makino; Nobuo Kamiya

1994-01-01

88

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

SciTech Connect

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

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

2011-07-18

89

Electro-caloric effect in lead-free Sn doped BaTiO3 ceramics at room temperature and low applied fields  

NASA Astrophysics Data System (ADS)

Structural, dielectric, ferroelectric (FE), 119Sn Mssbauer, and specific heat measurements of polycrystalline BaTi1-xSnxO3 (x = 0% to 15%) ceramics are reported. Phase purity and homogeneous phase formation with Sn doping is confirmed from x-ray diffraction and 119Sn Mssbauer measurements. With Sn doping, the microstructure is found to change significantly. Better ferroelectric properties at room temperature, i.e., increased remnant polarization (38% more) and very low field switchability (225% less) are observed for x = 5% sample as compared to other samples and the results are explained in terms of grain size effects. With Sn doping, merging of all the phase transitions into a single one is observed for x ? 10% and for x = 5%, the tetragonal to orthorhombic transition temperature is found close to room temperature. As a consequence better electro-caloric effects are observed for x = 5% sample and therefore is expected to satisfy the requirements for non-toxic, low energy (field) and room temperature based applications.

Upadhyay, Sanjay Kumar; Reddy, V. Raghavendra; Bag, Pallab; Rawat, R.; Gupta, S. M.; Gupta, Ajay

2014-09-01

90

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

NASA Astrophysics Data System (ADS)

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

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

2013-07-01

91

Improvement in piezoelectric strain of annealed Ba(Zr0.07Ti0.93)O3 based ceramics  

NASA Astrophysics Data System (ADS)

In the present work, effects of annealing time on strain behavior, densification, and microstructure of 2 wt. % B2O3 doped Ba(Zr0.07Ti0.93)O3 ceramics were investigated. The ceramics were initially sintered at 1150 to 1275 C for 2 h. After sintering, the densest ceramics (1250 C ceramics) were selected for annealing at 1000 C for 4-16 h. An increase in strain level and piezoelectric coefficient was observed after some annealing. High bipolar strain level of 0 .48% and high piezoelectric coefficients (d*33) of 603 pm/V were obtained for the 8 h samples. Longer annealing times (>8 h) resulted in reduction of the strain level and piezoelectric value. The change in piezoelectric properties was correlated with the densification and microstructure of the studied samples.

Jarupoom, Parkpoom; Rujijanagul, Gobwute

2013-07-01

92

Singular stress and electric fields of a piezoelectric ceramic strip with a finite crack under longitudinal shear  

Microsoft Academic Search

Summary Following the theory of linear piezoelectricity, we consider the problem of determining the singular stress and electric fields in an orthotropic piezoelectric ceramic strip containing a Griffith crack under longitudinal shear. The crack is situated symmetrically and oriented in a direction parallel to the edges of the strip. Fourier transforms are used to reduce the problem to the solution

Y. Shindo; K. Tanaka; F. Narita

1997-01-01

93

Effect of electric field on fracture of piezoelectric ceramics  

Microsoft Academic Search

Closed form solutions for all three modes of fracture for an infinite piezoelectric medium containing a center crack subjected to a combined mechanical and electrical loading were obtained. The explicit mechanical and electrical fields near the crack tip were derived, from which the strain energy release rate and the total potential energy release rate were obtained by using the crack

S. B. Park; C. T. Sun

1993-01-01

94

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

NASA Technical Reports Server (NTRS)

The properties of three PZT-based piezoelectric ceramics and one PLZT electrostrictive ceramic were measured as a function of temperature. In this work, the dielectric, ferroelectric polarization versus electric field, and piezoelectric properties of PZT-4, PZT-5A, PZT-5H, and PLZT-9/65/35 were measured over a temperature range of -150 to 250 C. In addition to these measurements, the relative thermal expansion of each composition was measured from 25 to 600 C and the modulus of rupture of each material was measured at room temperature. This report describes the experimental results and compares and contrasts the properties of these materials with respect to their applicability to intelligent aerospace systems.

Hooker, Matthew W.

1998-01-01

95

Enhanced piezoelectric property of porous lead zirconate titanate ceramics with one dimensional ordered pore structure  

SciTech Connect

Lead zirconate titanate (PZT) ceramics with one dimensional ordered pore structure (1-3 type porous PZT ceramics) were fabricated in this study. The special structure not only enhanced the piezoelectric and dielectric properties effectively but also further decreased the acoustic impedance. All samples exhibited excellent piezoelectric properties despite high porosities. The d{sub 33} value was 608 pC /N (remained 88% that of dense PZT) when the porosity was up to 68.7%. The d{sub 33} value was 690 pC /N (same as dense PZT) when the porosity was 41.7%. The lowest acoustic impedance (Z) reached 1.3 MRayls. These results are promising for improving performance in hydrophones applications.

Guo Rui; Wang Changan; Yang Ankun; Fu Juntao [Department of Materials Science and Engineering, State Key Lab of New Ceramics and Fine Processing, Tsinghua University, Beijing 100084 (China)

2010-12-15

96

Composition and temperature dependence of the dielectric, piezoelectric and elastic properties of pure PZT ceramics.  

PubMed

Pure (undoped) piezoelectric lead zirconate titanate (PZT) ceramic samples at compositions across the ferroelectric region of the phase diagram were prepared from sol-gel-derived fine powders. Excess lead oxide was included in the PZT powders to obtain dense (95-96% of theoretical density) ceramics with large grain size (>7 mum) and to control the lead stoichiometry. The dielectric, piezoelectric, and elastic properties were measured from 4.2 to 300 K. At very low temperatures, the extrinsic domain wall and thermal defect motions freeze out. The low-temperature dielectric data can be used to determine coefficients in a phenomenological theory. The extrinsic contribution to the properties can then be separated from the single-domain properties derived from the theory. PMID:18285000

Zhuang, Z Q; Haun, M J; Jang, S J; Cross, L E

1989-01-01

97

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

NASA Astrophysics Data System (ADS)

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

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

2012-08-01

98

Breakthrough: Lead-free Solder  

ScienceCinema

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

Anderson, Iver

2013-03-01

99

Optimum placement of piezoelectric ceramic modules for vibration suppression of highly constrained structures  

NASA Astrophysics Data System (ADS)

The vibration suppression efficiency of so-called shunted piezoelectric systems is decisively influenced by the number, shape, dimensions and position of the piezoelectric ceramic elements integrated into the structure. This paper presents a procedure based on evolutionary algorithms for optimum placement of piezoelectric ceramic modules on highly constrained lightweight structures. The optimization loop includes the CAD software CATIA V5, the FE package ANSYS and DynOPS, a proprietary software tool able to connect the Evolving Object library with any simulation software that can be started in batch mode. A user-defined piezoelectric shell element is integrated into ANSYS 9.0. The generalized electromechanical coupling coefficient is used as the optimization objective. Position, dimensions, orientation, embedding location in the composite lay-up and wiring of customized patches are determined for optimum vibration suppression under consideration of operational and manufacturing constraints, such as added mass, maximum strain and requirements on the control circuit. A rear wing of a racing car is investigated as the test object for complex, highly constrained geometries.

Belloli, Alberto; Ermanni, Paolo

2007-10-01

100

Thermal deformation analysis of curved actuator LIPCA with a piezoelectric ceramic layer and fiber composite layers  

Microsoft Academic Search

This paper reports thermal deformation analysis of LIPCA-C2 (Lightweight Piezo-composite Curved Actuator) that is lighter than other conventional piezo-composite type actuator. The LIPCA is composed of a piezoelectric ceramic layer which is sandwiched with composite layers having different CTE (coefficient of thermal expansion) and modulus. Due to the asymmetrical lay-up structure of LIPCA, an accurate analysis of thermally induced curvature

K. J. Yoon; K. H. Park; H. C. Park; D. Perreux

2003-01-01

101

Dielectric, piezoelectric, and ferroelectric properties of lanthanum-modified PZTFN ceramics  

NASA Astrophysics Data System (ADS)

Specimens of Pb1-1.5 x La x (Zr0.53Ti0.47)1- y- z Fe y Nb z O3 ( x = 0, 0.004, 0.008, 0.012, and 0.016, y = z = 0.01) (PZTFN) ceramics were synthesized by a semi-wet route. In the present study, the effect of La doping was investigated on the structural, microstructural, dielectric, piezoelectric, and ferroelectric properties of the ceramics. The results show that, the tetragonal (space group P4 mm) and rhombohedral (space group R3 c) phases are observed to coexist in the sample at x = 0.012. Microstructural investigations of all the samples reveal that La doping inhibits grain growth. Doping of La into PZTFN improves the dielectric, ferroelectric, and piezoelectric properties of the ceramics. The hysteresis loops of all specimens exhibit nonlinear behavior. The dielectric, piezoelectric and ferroelectric properties show a maximum response at x ? 0.012, which corresponds to the morphotropic phase boundary (MPB).

Kumar, Arvind; Mishra, S. K.

2014-10-01

102

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

NASA Astrophysics Data System (ADS)

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

Wang, Jianhua; Xiao, Zexin

2011-11-01

103

Detection of cancer biomarkers by piezoelectric biosensor using PZT ceramic resonator as the transducer.  

PubMed

A novel piezoelectric biosensor using lead titanate zirconate (PZT) ceramic resonator as transducer was developed for label-free, cost-effective, and direct detection of cancer biomarkers. We designed a dual sensing scheme where two ceramic resonators were connected in parallel, in which one resonator was used as the sensing unit and the other as the control unit, in order to minimize environment influences including temperature fluctuation and to achieve the required frequency stability for biosensing applications. Detection of selected cancer biomarkers, such as prostate specific antigen (PSA) and ?-fetoprotein (AFP) was carried out to evaluate the performance of the biosensor. The device showed high sensitivity (0.25 ng/ml) and fast detection (within 30 min) with small amount of sample (1 ?l), which is compatible to that required by clinical measurements. The results also showed that the ceramic resonator-based piezoelectric biosensor platform could be utilized with different chemical interfaces, and the miniaturized size of the ceramic resonators makes it suitable for fabricating sensor arrays for multiplex detection. PMID:23542085

Su, Li; Zou, Lan; Fong, Chi-Chun; Wong, Wing-Leung; Wei, Fan; Wong, Kwok-Yin; Wu, Rudolf S S; Yang, Mengsu

2013-08-15

104

Simultaneous measurement of electro-optical and converse-piezoelectric coefficients of PMN-PT ceramics.  

PubMed

A new scheme is proposed to measure the electro-optical (EO) and converse-piezoelectric (CPE) coefficients of the PMN-PT ceramics simultaneously, in which the PMN-PT ceramics acts as the guiding layer of a symmetrical metal-cladding waveguide. As the applied electric field exerts on the waveguide, the effective refractive index (RI) (or synchronous angle) can be effectively tuned from a selected mode to another adjacent mode owing to the high sensitivity and the small spacing of the ultra-high order modes. Subsequently, a correlation between EO and CPE coefficients is established. With this correlation and the measurement of the effective RI change to the applied voltage, the quadratic EO and CPE coefficients of PMN-PT ceramics are obtained simultaneously. The obtained results are further checked by fitting the variations of effective RI to a quadratic function. Our measurement method can be extended to a wide range of other materials. PMID:22714448

Xiao, Pingping; Wang, Xianping; Sun, Jingjing; Huang, Meizhen; Chen, Xianfeng; Cao, Zhuangqi

2012-06-18

105

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

NASA Astrophysics Data System (ADS)

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

Maurya, Deepam; Zhou, Yuan; Priya, Shashank

2013-03-01

106

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

107

Highly Efficient Low-frequency Energy Harvester Using Bulk Piezoelectric Ceramics  

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

108

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

PubMed

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

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

2011-09-01

109

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

NASA Astrophysics Data System (ADS)

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

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

2013-04-01

110

Modal analysis of the electromechanical conversion in piezoelectric ceramic spherical shells.  

PubMed

The current study considers piezoelectric ceramic electromechanical transducers utilizing axisymmetric vibrations of complete and incomplete spherical shells. Analysis is focused on generating the modes of vibration that can be employed in the design of multimode unidirectional electroacoustic transducers for underwater applications and on determining the electrode configurations that achieve optimal electromechanical coupling for the different modes of vibration considered. Analytical expressions are presented for the modal and intermodal equivalent parameters characterizing the energy state of the shell vibration. Results of calculation and experimental verification of the resonance frequencies and effective coupling coefficients for different modes of vibration of the complete and incomplete spherical shells are in good agreement. PMID:21877791

Aronov, Boris; Brown, David A; Yan, Xiang; Bachand, Corey L

2011-08-01

111

Effects of dopants on the piezoelectric and dielectric properties of Sm-modified PbTiO 3 ceramics  

Microsoft Academic Search

Doping effects on the piezoelectric and dielectric properties of PbTiO3-based ceramics have been investigated. Sm-modified PbTiO3 ceramics, doped with BiFeO3 (BF) and Ba(Cu0.5W0.5)O3(BCW), were prepared by conventional mixed-oxide methods with sintering temperatures of 10001250C. In this paper, we successfully show that these additives were helpful in lowering the sintering temperature while still obtaining similar dielectric and piezoelectric properties. The preferred

Sheng-Yuan Chu; Chia-Hsin Chen

2000-01-01

112

Piezoelectric and Pyroelectric Properties in Ferroelectric KTa0.3Nb0.7O3 Ceramics  

Microsoft Academic Search

Piezoelectric and pyroelectric properties of KTa0.3Nb0.7O3 ceramics which belong to the perovskite-ferroelectric ABO3 family, were studied. The piezoelectric constants (d31 = 18 pC\\/N, d33 = 28 pC\\/N and d15 = 19 pC\\/N) of these ceramics are higher than that for KNbO3. We found that the amplitudes of the fundamental frequency and its overtones for the thickness vibrations depend on the

H. Khemakhem; R. von der Mhll; A. Daoud; J. Ravez

1997-01-01

113

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

NASA Astrophysics Data System (ADS)

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

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

2012-07-01

114

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

NASA Technical Reports Server (NTRS)

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

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

2011-01-01

115

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

116

Microstructures, dielectric, and piezoelectric properties of W/Cr co-doped Bi4Ti3O12 ceramics  

NASA Astrophysics Data System (ADS)

W/Cr co-doped Bi4Ti3O12 (BTWC) ceramics {Bi4Ti3-xWxO12 + x + 0.2 wt. % Cr2O3 (x = 0-0.1)} with a high piezoelectricity were prepared by a conventional ceramic process, and effects of W/Cr dopant on the microstructures, dielectric, and piezoelectric properties of ceramics were explored. It is found that W6+ modified the grain morphology and size of ceramics, promoting the forming of the regular schistose grains with a size of 10 ?m in the ceramic at x = 0.05. BTWC ceramics showed a continuous decrease in Tc and a gradual increase in ?r with the increasing W doping content. While the hard-doping of Cr2O3 decreased, the TK? and tan ? of ceramics available. All the ceramics keep the nature of first-order transition and displacive ferroelectrics. The d33 and kp of BTWC ceramics were remarkably improved by the soft-doping of W6+. Excellent electrical properties (e.g., Tc = 638 C, ?r = 146, tan ? = 0.56%, TK? (500 C) = 1.30 10-3/ C, ? (500 C) = 4.08 10-5 s, d33 = 28 pC/N, and kp = 6.17%) have been achieved in Bi4Ti2.95W0.05O12.05 + 0.2 wt. % Cr2O3 ceramic. Such a material can be a promising candidate for high-temperature piezoelectric applications.

Chen, Yu; Liang, Dayun; Wang, Qingyuan; Zhu, Jianguo

2014-08-01

117

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

PubMed

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

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

2011-09-01

118

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

PubMed Central

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

Gonzalez-Moran, Carlos O.; Flores-Cuautle, J.J. Agustin; Suaste-Gomez, Ernesto

2010-01-01

119

Characterization of Piezoelectric Ceramic Transducer for Accurate Speed-of-Sound Measurement  

NASA Astrophysics Data System (ADS)

Piezoelectric ceramics mounted on the endplates of a cylindrical resonator were used as the source and detector for speed-of-sound measurements. The perturbations of the longitudinal gas modes of the cavity due to the compliance of the diaphragms (10 mm diameter, 0.3 mm thick) and the attached transducers were estimated from first-order perturbation theory. The fractional shift of the resonance frequencies in argon caused by the source and detector was 0.03 10-6 at 0.1 MPa and 273.16 K. The high signal-to-noise ratio (up to 1 104 with a 6 s integration time) that was obtained with these transducers makes them suitable for acoustic thermometry. The heat dissipation in the source transducer was measured to be only 0.7 ?W at the working voltage (7 V) and frequency (1 kHz).

Lin, H.; Gillis, K. A.; Zhang, J. T.

2010-07-01

120

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

PubMed

A technique was developed for the solder attachment of coaxial cable leads to silver-bearing thick-film electrodes on piezoelectric ceramics. Soldering the cable leads directly to the thick film caused bonds with low mechanical strength due to poor solder joint geometry. A barrier coating of 1.5 mum Cu/1.5 mum Ni/1.0 mum Sn deposited on the thick-film layer improved the strength of the solder joints by eliminating the adsorption of Ag from the thick film, which was responsible for the improper solder joint geometry. The procedure does not require special preparation of the electrode surface and is cost effective due to the use of nonprecious metal films and the batch processing capabilities of the electron beam deposition technique. PMID:18263219

Vianco, P T

1993-01-01

121

Mechanical characterization of sintered piezo-electric ceramic material using scanning acoustic microscope.  

PubMed

Lead Zirconate Titanate (PZT) is a piezo-electric ceramic material that needs to be characterized for its potential use in microelectronics. Energy dispersive X-ray analysis (EDX) is conducted to determine the chemical composition of the PZT ceramics. The scanning electron microscope (SEM) is performed to study the surface morphology, grain structure and grain boundaries. The SEM image helps us to understand the surface wave propagation and scattering phenomena by the PZT and the reason for its anisotropy and inhomogeneity due to the grain structure. In this paper scanning acoustic microscopy at 100 MHz excitation frequency is conducted for determining mechanical properties of PZT. Earlier works reported only the longitudinal wave speed in PZT while in this paper longitudinal, shear and surface acoustic wave speeds of sintered PZT are measured from its acoustic material signature (AMS) curves, also known as V(z) curves. AMS or V(z) curve is the variation of the output voltage as a function of the distance between the acoustic lens focal point and the reflecting surface. The average velocities of longitudinal, shear and surface acoustic waves in a PZT specimen are determined from its V(z) curve generated at 100 MHz excitation frequency and found to be over 5000 m/s, over 3000 m/s and between 2500 and 3000 m/s, respectively. From these velocities all elastic constants of the specimen are obtained. PMID:22989949

Habib, A; Shelke, A; Vogel, M; Pietsch, U; Jiang, Xin; Kundu, T

2012-12-01

122

The piezoelectric and dielectric properties of Cd additive Sm-modified PbTiO 3 ceramics  

Microsoft Academic Search

Effects of cadmium dopants on the piezoelectric and dielectric properties of Sm-modified PbTiO3 ceramics have been investigated. Sm-modified lead PbTiO3 ceramics with a composition of (Pb0.85?xCdxSm0.1)(Ti0.98Mn0.02)O3, x=0.010.08 were prepared by conventional mixed-oxide methods with sintering temperature at 1150C. We successfully showed that Cd additive is helpful to grow the grain size and obtain much higher thickness electromechanical coupling coefficient, kt

Te-Yi Chen; Sheng-Yuan Chu; Shih-Jeh Wu; Yung-Der Juang

2002-01-01

123

Effect of calcium on the piezoelectric and dielectric properties of Sm-modified PbTiO 3 ceramics  

Microsoft Academic Search

In this paper, effects of calcium dopants on the piezoelectric and dielectric properties of Sm-modified lead titanate (PbTiO3) ceramics have been investigated. Sm-modified PbTiO3 ceramics with a composition of (Pb0.88?xCaxSm0.08)(Ti0.98Mn0.02)O3; x=0.110.17 were prepared by conventional mixed-oxide methods with sintering temperature at 1200C. We successfully showed that Ca additive is helpful to obtain much higher thickness electromechanical coupling coefficient, kt (>0.57),

Sheng-Yuan Chu; Chia-Hsin Chen

2001-01-01

124

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

125

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

NASA Astrophysics Data System (ADS)

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

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

2013-07-01

126

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

NASA Astrophysics Data System (ADS)

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

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

2014-09-01

127

Elastic, piezoelectric, and dielectric characterization of modified BiScO3-PbTiO3 ceramics.  

PubMed

The perovskite solid solution system (1-x)BiScO3-(x)PbTiO3 represents an interesting new family of high-temperature piezoelectric materials. Compositions near the morphotropic phase boundary (x approximately 0.64) have been reported to have high Curie temperatures (Tc > 450 degrees C) and good piezoelectric coefficients (d33 approximately 460 pC/N). In this work, manganese additions were used to improve the high-temperature electrical resistivity and RC time constant of compositions near the morphotropic phase boundary. The addition of manganese was found to shift Tc to slightly lower temperatures (442 degrees C and 456 degrees C for x = 0.64 and x = 0.66, respectively). The piezoelectric activities of the modified materials were found to be reduced slightly due to the hardening effect of manganese; however, the temperature stability and resistivity of the modified materials were significantly enhanced. In this paper we present, for the first time, a complete set of materials constants, including the elastic (sij, cij), piezoelectric (dij, eij, gij, hij), dielectric (epsilonij, betaij), and electromechanical (kij) coefficients and compare them to both unmodified 0.36BiScO3-0.64PbTiO3 and PZT5A ceramics. PMID:16422427

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

2005-11-01

128

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

NASA Astrophysics Data System (ADS)

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

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

2012-04-01

129

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

NASA Astrophysics Data System (ADS)

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

Fu, Jian; Zuo, Ruzhong

2013-03-01

130

Structural characteristics of Mg-doped (1-x)(K0.5Na0.5)NbO3-xLiSbO3 lead-free ceramics as revealed by Raman spectroscopy  

NASA Astrophysics Data System (ADS)

This paper presents a Raman spectroscopic study of compositional-change-induced structure variation and of the related mechanism of Mg doping in LiSbO3 (LS)-modified (K0.5Na0.5)NbO3 (KNN) ceramics. With increasing LS content from 0 to 0.06, a discontinuous shift towards higher wavenumbers was found for the band position of the A1g(v1) stretching mode of KNN, accompanied by a clearly nonlinear broadening of this band and a decrease in its intensity. Such morphological changes in the Raman spectrum result from two factors: (i) changes in polarizability/binding strength of the O-Nb-O vibration upon incorporation of Li ions in the KNN perovskitic structure and (ii) a polymorphic phase transition (PPT) from orthorhombic to tetragonal (O ? T) phase at x > 0.04. Upon increasing the amount, w, of Mg dopant incorporated into the (1-x)KNN-xLS ceramic structure, the intensity of the Raman bands are enhanced, while the peak position and the full width at half maximum of the A1g(v1) mode was found to experience a clear dependence on both w and x. Raman characterization revealed that the mechanism of Mg doping is strongly correlated with the concentration of Li in the perovskite structure: Mg2+ ions will preferentially replace Li+ ions for low Mg doping while replace K/Na ions for higher doping of Mg. The PPT O ? T was also found to be altered by the introduction of Mg and the critical value of LS concentration, xO-T, for incipient O ? T transition in the KNN-xLS-wMT system was strongly dependent on Mg content, with xO ? T being roughly equal to 0.04 + 2w, for the case of dilute Mg alloying.

Zhu, W. L.; Zhu, J. L.; Meng, Y.; Wang, M. S.; Zhu, B.; Zhu, X. H.; Zhu, J. G.; Xiao, D. Q.; Pezzotti, G.

2011-12-01

131

Lead-Free Reflow Oven Parameter Optimization  

Microsoft Academic Search

Because of the potential danger that Lead poses to human health, Parliament of the European Union approved a law to take effect on July 1, 2006 which forbids the use of lead in electrical and electronic products. As a result, manufacturers throughout the world started to look into replacing lead-based solder with lead-free pastes using a combination of alloys. During

Manuel Mira; James Z. Zhang; Aaron K. Ball

132

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

133

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

NASA Astrophysics Data System (ADS)

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

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

2014-01-01

134

Label-free detection of endocrine disrupting chemicals by integrating a competitive binding assay with a piezoelectric ceramic resonator.  

PubMed

A piezoelectric biosensor for detection of endocrine disrupting chemicals (EDCs) was developed by incorporating chemical/biochemical recognition elements on the ceramic resonator surface for competitive binding assays. A facile electrodeposition was employed to modify the sensor surface with Au nanoparticles, which increased the surface area and enhanced the binding capacity of the immobilized probes. Thiol-labeled long chain hydrocarbon with bisphenol A (BPA) as head group was synthesized and self-assembled on the Au nanoparticle surface as the sensing probes, which showed a linear response upon the binding of estrogen receptor (ER-?) ranging from 1 to 30 nM. Detection of estrone, 17?-estradiol and BPA was achieved by integrating a competitive binding assay with the piezoelectric sensor. In this detection scheme, different concentrations of EDCs were incubated with 30 nM of ER-?, and the un-bounded ER-? in the solution was captured by the probes immobilized on the ceramic resonator, which resulted in the frequency changes for different EDCs. The biosensor assay exhibited a linear response to EDCs with a low detection limit of 2.4-2.9 nM (S/N=3), and required only a small volume of sample (1.5 l) with the assay time of 2h. The performance of the biosensor assay was also evaluated for rapid and facile determination of EDCs of environmental relevant concentrations in drinking water and seawater, and the recovery rate was in the range between 94.7% and 109.8%. PMID:24201004

Hu, Liang-sheng; Fong, Chi-Chun; Zou, Lan; Wong, Wing-Leung; Wong, Kwok-Yin; Wu, Rudolf S S; Yang, Mengsu

2014-03-15

135

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

NASA Astrophysics Data System (ADS)

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

Zong, Ximei; Yang, Zupei

2014-11-01

136

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

NASA Astrophysics Data System (ADS)

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

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

2014-06-01

137

Piezoelectric activity of relaxor-PbTiO3 based single crystals and polycrystalline ceramics at cryogenic temperatures: Intrinsic and extrinsic contributions  

PubMed Central

The piezoelectric activity in [001] poled Pb(In1?2Nb1?2)O3Pb(Mg1?3Nb2?3)O3PbTiO3 crystals was investigated as a function of composition and temperature. The level of intrinsic and?or extrinsic contribution to the total piezoelectric activity was analyzed using Rayleigh method. The results revealed that though 95% of the observed piezoelectric activity in rhombohedral crystals was intrinsic (lattice), the properties decreased significantly with decreasing temperature. At ?150 C, the piezoelectric response decreased by 40%55% for the compositions close to a morphotropic phase boundary (rhombohedral-monoclinic or monoclinic-tetragonal), while decreasing only 20%30% for the compositions in the rhombohedral region. The piezoelectric properties of Pb(Mg1?3Nb2?3)O3PbTiO3 polycrystalline ceramics were found to decrease by 75%, showing both intrinsic and extrinsic contributions play important role in the reduction in piezoelectricity at cryogenic temperatures for ceramics. PMID:20531980

Li, Fei; Zhang, Shujun; Xu, Zhuo; Wei, Xiaoyong; Luo, Jun; Shrout, Thomas R.

2010-01-01

138

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

SciTech Connect

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

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

2009-05-01

139

Effects of sintering temperature on the dielectric and piezoelectric properties of Sr additive Sm-modified PbTiO 3 ceramics  

Microsoft Academic Search

(Pb0.88?xSrxSm0.08)(Ti0.98Mn0.02)O3 ceramics; x=0.050.25 were prepared by conventional mixed-oxide technique, with sintering temperature at 11251250C. Microstructural and compositional analyses of these doped ceramics have been carried out using X-ray diffraction (XRD) and scanning electron microscope (SEM). The effects of dopants and the sintering temperature on the piezoelectric and dielectric properties of Sm-modified PbTiO3 ceramics have been investigated. We successfully showed that

Te-Yi Chen; Sheng-Yuan Chu; Yung-Der Juang

2002-01-01

140

Doping effects of strontium on the piezoelectric and dielectric properties of Ca additive Sm-modified PbTiO 3 ceramics  

Microsoft Academic Search

Effects of Sr dopants on the piezoelectric and dielectric properties of (Ca, Sm)-modified PbTiO3 ceramics have been investigated. The modified lead PbTiO3 ceramics with a composition of (Pb0.73?xCa0.15SrxSm0.08)(Ti0.98Mn0.02)O3; x=0.050.1 were prepared by conventional mixed-oxide methods with sintering temperature at 1200C. Microstructural and compositional analyses of these doped ceramics have been carried out using XRD and SEM. We successfully showed that

Sheng-Yuan Chu; Te-Yi Chen

2004-01-01

141

Piezoelectric transducer materials  

Microsoft Academic Search

Properties of piezoelectric crystals and ceramics are reviewed as they affect use of such materials in electroacoustic transducers. Extensive data on lead titanate-zirconate ceramics are presented to help in selection of the appropriate material for a variety of applications in the lower and medium frequency range, up to several megacycles per second. Quartz and several recently discovered piezoelectric crystals will

H. Jaffe; D. A. Berlincourt

1965-01-01

142

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

SciTech Connect

The continuing need for large actuation and a continually increasing variety of applications has seen the use of piezoelectric materials under a growing range of conditions. These include large applied AC fields, DC bias fields, applied stresses as well as a wider range of frequencies and temperatures. Under these conditions the behaviour of the materials becomes non-linear and is not described well by the small signal parameters supplied by material manufacturers. It is therefore necessary to know and understand the behaviour of piezoelectric materials under these conditions. This presentation reviews the work that has been carried out at the Laboratory for Ferroelectric Materials in the Royal Military College of Canada where we have been studying the non-linear properties of piezoelectric and electrostrictive materials by observing their strain, dielectric and elastic behaviour under the various conditions mentioned above.

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

2008-07-29

143

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

NASA Astrophysics Data System (ADS)

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

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

2014-02-01

144

Piezoelectric properties of nonstoichiometric Sr1-xBi2+2x/3Ta2O9 ceramics  

NASA Astrophysics Data System (ADS)

The effect of poling on the structural, dielectric, and piezoelectric properties has been investigated for sol-gel-derived strontium bismuth tantalate (SBT) [Sr1-xBi2+2x/3Ta2O9] ceramics with x =0.0,0.15,0.30,0.45. The dielectric and ferroelectric properties are found to improve with increase in x up to 0.3. Beyond x >0.3 the properties are found to degrade due to the limited solid solubility and the presence of a mixed phase of bismuth tantalate (BiTaO4) is detected with x =0.45. Poling treatment reduces the dielectric dispersion and dielectric loss in the frequency range (0.1-100kHz). The resonance and antiresonance frequencies increase with increase in x (x=0-0.30), and the corresponding minimum impedance decreases. The measured coupling coefficients (kp) are small (0.0967-0.1) for x =0-0.30, and the electromechanical quality factor (Qm=915) is a maximum for the Sr0.7Bi2.2Ta2O9 composition (x=0.30). The estimated piezoelectric charge coefficient (d31) and piezoelectric voltage coefficient (g31) are 5.2pC/N and 5.810-3Vm/N, respectively. The positive values of d31 and g31 and the low dielectric permittivity of SBT yield a high value for the hydrostatic coefficients, despite the low charge coefficient of d33=24pC/N. The maximum values of charge coefficient (dh=34pC/N) and voltage coefficient (gh=3910-3Vm/N) are obtained for Sr0.7Bi2.2Ta2O9 composition, and the estimated hydrostatic figure of merit (dhgh10-15=1215m2/N) is high.

Jain, Rajni; Chauhan, Arun Kumar Singh; Gupta, Vinay; Sreenivas, K.

2005-06-01

145

Processing of Fine-Scale Piezoelectric Ceramic/Polymer Composites for Sensors and Actuators  

NASA Technical Reports Server (NTRS)

The objective of the research effort at Rutgers is the development of lead zirconate titanate (PZT) ceramic/polymer composites with different designs for transducer applications including hydrophones, biomedical imaging, non-destructive testing, and air imaging. In this review, methods for processing both large area and multifunctional ceramic/polymer composites for acoustic transducers were discussed.

Janas, V. F.; Safari, A.

1996-01-01

146

Applications of laser holography in vibratory analysis of piezoelectric ceramics and transducers  

Microsoft Academic Search

In this paper the vibratory holograms of piezoelectric elements and transducers under resonance state are investigated by means of the time-average method of laser holography. Also investigated are a series of dynamic vibratory characteristics calculated from holograms, such as vibratory type, amplitude, relations between amplitude and excitation voltage, relations between amplitude and frequencies, amplitude distribution on the vibratory face etc.

Suolong Yu; Deqing Yang

1992-01-01

147

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

148

NASA-DoD Lead-Free Electronics Project  

NASA Technical Reports Server (NTRS)

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

Kessel, Kurt

2010-01-01

149

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

150

Local characterization of nanostructured high sensitivity piezoelectric BiScO3-PbTiO3 ceramics by piezoresponse force microscopy  

NASA Astrophysics Data System (ADS)

Piezoresponse force microscopy has been used for the local characterization of high sensitivity piezoelectric BiScO3-PbTiO3 ceramics with compositions close to the morphotropic phase boundary, with decreasing grain sizes down to 28 nm. The use of this high resolution technique has allowed not only the analysis of the evolution of the ferroelectric domain configurations, with the disappearance of ferroelastic domains at the nanoscale, but also to establish the existence of correlations among the polarization of adjacent single-domain grains and the formation of inversion superdomains. The effect of the grain size reduction on the piezoelectric coefficients was also studied. Finally, piezoelectric loops have been obtained on the smallest grains, and some distinctive features, such as an atypical clockwise hysteresis is discussed and related to high resistivity grain boundaries.

Salazar, Norberto; Alguer, Miguel; Amorn, Harvey; Castro, Alicia; Gil, Adriana; Ricote, Jess

2014-09-01

151

The piezoelectric and dielectric properties of Ca-additive Sm-modified PbTiO 3 ceramics intended for surface acoustic wave devices  

Microsoft Academic Search

Sm-modified lead titanate ceramics with a composition of (Pb0.88?xCaxSm0.08)(Ti0.98Mn0.02)O3; x=0.11?0.17 were prepared by conventional mixed-oxide method. The dielectric and piezoelectric properties of these doped ceramics were measured at room temperature. Microstructural and compositional analyses have been carried out using SEM and XRD. The Curie point (Tc) was studied by measuring the dielectric behavior as a function of temperature. The experiments

Te-Yi Chen; Sheng-Yuan Chu

2003-01-01

152

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

NASA Astrophysics Data System (ADS)

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

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

2007-10-01

153

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

Microsoft Academic Search

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

Mikio Umeda; Kentaro Nakamura; Sadayuki Ueha

1999-01-01

154

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

NASA Astrophysics Data System (ADS)

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

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

2014-01-01

155

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

SciTech Connect

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

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

2012-05-15

156

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

SciTech Connect

We report porous lead zirconate titanate ceramics fabricated by tert-butyl alcohol-based gel-casting process which show a very high thickness electromechanical coupling coefficient (0.77), high hydrostatic figure of merit (9594x10{sup -15} m{sup 2}/N), and low acoustic impedance (3.7 Mrayls). We show that the porosity effectively affects the performance of the samples in two ways: (1) a higher porosity simplifies the resonance behavior, leading to more efficient energy transduction; (2) its replacement of active ceramic phase leads to low relative permittivity, high hydrostatic figure of merit, and low acoustic impedance. It was confirmed the properties could be tailored by controlling the porosity.

Yang Ankun; Wang Changan; Guo Rui; Huang Yong [Department of Materials Science and Engineering, State Key Laboratory of New Ceramics and Fine Processing, Tsinghua University, Beijing 100084 (China)

2011-04-11

157

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

SciTech Connect

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

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

1995-04-01

158

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

159

All lead free IGBT module with excellent reliability  

Microsoft Academic Search

The subject of lead free solder application of IGBT module is reliability of solder under the insulated substrate in temperature cycling test. This paper presents all lead free IGBT modules with excellent reliability. This was achieved by optimizing of the thermal expansion coefficient of insulated substrate and using Sn-Ag-In solder.

Y. Nishimura; K. Oonishi; A. Morozumi; E. Mochizuki; Y. Takahashi

2005-01-01

160

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

161

Lead-free KNbO3 ferroelectric nanorod based flexible nanogenerators and capacitors  

NASA Astrophysics Data System (ADS)

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 KNbO3 ferroelectric nanorods (1 ?m length) with piezoelectric coefficient (d33 55 pm V -1). A flexible piezoelectric nanogenerator is mainly composed of KNbO3-poly(dimethylsiloxane) (PDMS) composite sandwiched by Au/Cr-coated polymer substrates. We deposit a thin poly(methyl methacrylate) (PMMA) layer between the KNbO3-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 KNbO3-PDMS composite device shows a nearly frequency-independent dielectric constant (3.2) and low dielectric loss (<0.006) for the frequency range of 102-105 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.

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

2012-09-01

162

Forced responses of solid axially polarized piezoelectric ceramic finite cylinders with internal losses.  

PubMed

A method is presented to determine the forced responses of piezoelectric cylinders using weighted sums of only certain exact solutions to the equations of motion and the Gauss electrostatic conditions. One infinite set of solutions is chosen such that each field variable is expressed in terms of Bessel functions that form a complete set in the radial direction. Another infinite set of solutions is chosen such that each field variable is expressed in terms of trigonometric functions that form a complete set in the axial direction. Another solution is used to account for the electric field that can exist even when there is no vibration. The weights are determined by using the orthogonal properties of the functions and are used to satisfy specified, arbitrary, axisymmetric boundary conditions on all the surfaces. Special cases including simultaneous mechanical and electrical excitation of cylinders are presented. All numerical results are in excellent agreement with those obtained using the finite element software ATILA. For example, the five lowest frequencies at which the conductance and susceptance of a stress-free cylinder, of length 10 mm and radius 5 mm, reach a local maximum or minimum differ by less than 0.01% from those computed using ATILA. PMID:16018468

Ebenezer, D D; Ravichandran, K; Ramesh, R; Padmanabhan, Chandramouli

2005-06-01

163

Characterization of Nanoparticles of Lead Free Solder Alloys  

Microsoft Academic Search

Nanoparticles of Sn-4.0Ag-0.5Cu and Sn-0.4Co-0.7Cu (wt% composition) lead free solder alloys were manufactured and characterized for potential applications in microelectronics packaging. Scanning electron microscopy (SEM) analysis was carried out in order to study the morphology and size distribution of the nanoparticles. It was observed that nanoparticles of lead free alloys were almost spherical in shape. The observed size distribution of

Wanbing Guan; S. C. Verma; Yulai Gaol; Cristina Andersson; Qijie Zhail; J. Liu

2006-01-01

164

Dielectric and piezoelectric properties of S001fiber-textured 0.675Pb,,Mg13Nb23...O3 0.325PbTiO3 ceramics  

E-print Network

­0.325PbTiO3 PMN­32.5PT ceramic composition with 1 wt. % excess PbO was fiber textured in the 001Dielectric and piezoelectric properties of S001fiber-textured 0.675Pb,,Mg1?3Nb2?3...O3 ­0.325PbTiO3 ceramics Edward M. Sabolsky,a) Susan Trolier-McKinstry, and Gary L. Messing Materials Research

Messing, Gary L.

165

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

Microsoft Academic Search

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

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

2009-01-01

166

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

SciTech Connect

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

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

2012-04-15

167

Evaluation of energy consumption of lead-free soldering process  

Microsoft Academic Search

Now the electronics industry is due to substitute lead-free solder for conventional solder. Substitution of lead-bearing solders can bring out reduction of the toxicity of solders caused by lead, but according to Life Cycle Analysis (LCA), it may cause increase of energy consumption in the soldering process. We investigated the energy consumption of the soldering process at production sites of

Masahisa Fujino; Tadatomo Suga

2003-01-01

168

Automatic and Secure Rework in a Lead-Free Environment  

Microsoft Academic Search

The evolution of electronic components as well as the lead-free changeover is a challenge for the production. In addition to that, we need to focus on the same issues also in rework processes. In the field of automated rework, it's indispensable to master a handful of important process parameters in order to get reliable and repeatable results. ZEVAC AG as

B. Affolter

2006-01-01

169

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

170

Rare earths in lead-free oxyfluoride germanate glasses.  

PubMed

Spectroscopic properties of rare earths in lead-free oxyfluoride germanate glasses were studied. The absorption and luminescence spectra of Eu(3+), Pr(3+) and Er(3+) ions were examined as a function of BaF? concentration and several spectroscopic parameters for rare earths were determined. The ratio of integrated luminescence intensity of the (5)D??(7)F? transition to that of the (5)D??(7)F? transition of Eu(3+) decrease significantly with increasing BaF? content. The absorption (Er(3+)) and emission (Pr(3+)) 'hypersensitive transitions' of rare earths are shifted in direction to shorter wavelengths with increasing BaF? content in glass composition. Emission spectra and their decays corresponding to the main (4)I??/??(4)I??/? laser transition of Er(3+) were also analyzed. Quite long-lived NIR luminescence of Er(3+) is observed for lead-free glass samples with low BaF? concentration. PMID:25088539

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

2015-01-01

171

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

172

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

SciTech Connect

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

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

2012-11-15

173

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

174

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

175

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),\\u000a new Sn-Zn-ln based alloys with substantially the same melting point have been developed. It is shown that the alloying additions\\u000a of In to the Sn-Zn binary system result in a suppression of the melting point to 175-188C, and at the same

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

1994-01-01

176

Investigation of high Curie temperature (1-x)BiSc{sub 1-y}Fe{sub y}O{sub 3}-xPbTiO{sub 3} piezoelectric ceramics  

SciTech Connect

Ceramics around the morphotropic phase boundary (MPB) in the (1-x)BiSc{sub 1-y}Fe{sub y}O{sub 3}-xPbTiO{sub 3} solid solution were fabricated. For y=0.5, ceramics were single phase, and piezoelectric coefficients (d{sub 33}) and electromechanical coupling coefficients (k{sub p}) for MPB compositions were 300 pC/N and 0.49, respectively; a level of piezoelectric activity similar to that of hard, lead zirconate titanate compositions but with T{sub C}approx60 deg. C higher at approx440 deg. C. For ceramics with y>=0.7, dielectric measurements in combination with diffraction contrast transmission electron microscopy revealed the existence of two ferroelectric phases for most PbTiO{sub 3} contents studied. The presence of two ferroelectric phases was associated with a decrease in piezoelectric activity and although raw materials costs for y=0.7 and 0.8 with respect to y=0 were significantly lower (less Sc{sub 2}O{sub 3}) and T{sub C} greater (approx500 deg. C), d{sub 33} (approx100 pC/N) and k{sub p} (0.18) were too low to be commercially useful for actuator applications.

Sterianou, I.; Sinclair, D. C.; Reaney, I. M. [Department of Engineering Materials, The University of Sheffield, Sheffield S1 3JD (United Kingdom); Comyn, T. P.; Bell, A. J. [Institute for Materials Research, University of Leeds, Leeds LS2 9JT (United Kingdom)

2009-10-15

177

Lead-free bearing alloys for engine applications  

NASA Astrophysics Data System (ADS)

Recent developments to reduce the fuel consumption, emission and air pollution, size and weight of engines for automotive, truck, ship propulsion and electrical power generation lead to temperature and load conditions within the engines that cannot be borne by conventional bearings. Presently, only costly multilayer bearings with electroplated or sputtered surface coatings can cope with the load/speed combinations required. Ecological considerations in recent years led to a ban by the European Commission on the use of lead in cars a problem for the standard bronze-lead bearing material. This MAP project is therefore developing an aluminium-based lead-free bearing material with sufficient hardness, wear and friction properties and good corrosion resistance. Only alloys made of components immiscible in the molten state can meet the demanding requirements. Space experimentation plays a crucial role in optimising the cast microstructure for such applications.

Ratke, Lorenz; gren, John; Ludwig, Andreas; Tonn, Babette; Grnsy, Lszl; Mathiesen, Ragnvald; Arnberg, Lars; Anger, Gerd; Reifenhuser, Bernd; Lauer, Michael; Garen, Rune; Gust, Edgar

2005-10-01

178

Fano resonance and dipolar relaxation in lead-free relaxors.  

PubMed

Fano resonance is a phenomenon in which a discrete state interferes with a continuum of states and has been observed in many areas of science. Here, we report on the prediction of a Fano resonance in ferroelectric relaxors, whose properties are poorly understood: an ab initio molecular dynamic scheme reveals such resonance between the bare optical phonon mode of the Zr sublattice (the discrete state) and the bare optical phonon mode of the Ti sublattice (the continuum of states) in disordered lead-free Ba(Zr,Ti)O3. The microscopic origins of the discrete state and continuum of states are discussed in the context of relaxor properties. Furthermore, our simulations suggest that the T* characteristic temperature of relaxor is related to a hardening of the vibrational frequencies associated with fluctuation of the Ti sublattice. Finally, a terahertz relaxation mode reflecting reorientations of Ti dipoles and showing a thermally activated behaviour is predicted, in agreement with previous experiments. PMID:25369904

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

2014-01-01

179

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

NASA Astrophysics Data System (ADS)

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

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

2014-09-01

180

ceramics  

NASA Astrophysics Data System (ADS)

The dielectric properties of Sm1.5Sr0.5NiO4- ? ceramics with different concentrations of oxygen vacancies were characterized. The ceramics with lower concentration of oxygen vacancies were prepared by directly sintering the sol-gel derived powders in air, while the higher one could be obtained by annealing the as-sintered ceramics in the flow of nitrogen. The post-densification annealing in the flow of nitrogen decreased the dielectric constant at low temperature and increased it at high temperature, while the dielectric loss increased in overall temperature range. The activation energy of low-temperature dielectric relaxation decreased with increasing the concentration of oxygen vacancies, and so did that of bulk electrical resistances although the values of resistances increased, while the activation energy of electrical resistances for grain boundary increased though the values of resistances decreased. The giant dielectric response in the as-sintered Sm1.5Sr0.5NiO4- ? ceramics should be mainly attributed to the small polaronic hopping process, while that of annealed ceramics should be directly linked to the oxygen vacancies.

Liu, G.; Liu, X. Q.; Chen, X. M.

2014-09-01

181

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

SciTech Connect

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

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

2009-03-15

182

Ferroelectric and Piezoelectric Properties of KNbO3 Ceramics Containing Small Amounts of LaFeO3  

Microsoft Academic Search

Dense KNbO3 ceramics have been successfully synthesized by pressure-less sintering under optimized heat-treatment conditions using a small amount of La2O3 and Fe2O3 additives. KNbO3 forms (K1-xLax)(Nb1-xFex)O3 solid solutions and changes in the crystal system, depending on the additive content, from orthorhombic to tetragonal at x of 0.020, and from tetragonal to cubic at x of 0.200 or higher. When only

Ken-ichi Kakimoto; Izumi Masuda; Hitoshi Ohsato

2003-01-01

183

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

E-print Network

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

Cao, Wenwu

184

Ceramics  

NASA Astrophysics Data System (ADS)

The effects of Ta2O5/Y2O3 codoping on the microstructure and microwave dielectric properties of Ba(Co0.56Zn0.40)1/3Nb2/3O3- xA- xB (A = 0.045 wt.% Ta2O5; B = 0.113 wt.% Y2O3) ceramics ( x = 0, 1, 2, 4, 8, 16, 32) prepared according to the conventional solid-state reaction technique were investigated. The x-ray diffraction (XRD) results showed that the main crystal phase in the sintered ceramics was BaZn0.33Nb0.67O3-Ba3CoNb2O9. The additional surface phase of Ba8CoNb6O24 and trace amounts of Ba5Nb4O15 second phase were present when Ta2O5/Y2O3 was added to the ceramics. The 1:2 B-site cation ordering was affected by the substitution of Ta5+ and Y3+ in the crystal lattice, especially for x = 4. Scanning electron microscopy (SEM) images of the optimally doped ceramics sintered at 1340C for 20 h showed a compact microstructure with crystal grains in dense contact. Though the dielectric constant increased with the x value, appropriate addition would result in a tremendous modification of the Q f and ? f values. Excellent microwave dielectric properties ( ? r = 35.4, Q f = 62,993 GHz, and ? f = 2.6 ppm/C) were obtained for the ceramic with x = 0.4 sintered in air at 1340C for 20 h.

Bin, Tang; Feng, Si; Ying-xiang, Li; He-tuo, Chen; Xiao, Zhang; Shu-ren, Zhang

2014-11-01

185

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

NASA Astrophysics Data System (ADS)

Pb(Zr,Ti)O3 (PZT) based compositions have been challenging to texture or grow in a single crystal form due to the incongruent melting point of ZrO2. Here we demonstrate the method for achieving 90% textured PZT-based ceramics and further show that it can provide highest known energy density in piezoelectric materials through enhancement of piezoelectric charge and voltage coefficients (d and g). Our method provides more than 5 increase in the ratio d(textured)/d(random). A giant magnitude of d.g coefficient with value of 59 000 10-15 m2 N-1 (comparable to that of the single crystal counterpart and 359% higher than that of the best commercial compositions) was obtained.

Yan, Yongke; Cho, Kyung-Hoon; Maurya, Deepam; Kumar, Amit; Kalinin, Sergei; Khachaturyan, Armen; Priya, Shashank

2013-01-01

186

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

187

Ceramics  

NASA Astrophysics Data System (ADS)

The effects of excess Li content on the phase structure and microwave dielectric properties, especially on the temperature coefficient, of LiNb0.6 Ti0.5O3 (LNT) ceramics were studied. The results show that small amounts of Li effectively enhanced the sintering process due to the compensation of high volatility of Li, leading to a densification and homogenous microstructure, and therefore enhanced the dielectric properties. However, too much Li leads to a secondary phase and cause abnormal grain growth. The LNT + 5 wt.% Li ceramic sintered at 1075C in the air shows the best properties of ? r = 69.73, Q f = 5543 GHz, and ? f = -4.4 ppm/C.

Li, Enzhu; Zou, Mengying; Duan, Shuxin; Xu, Ning; Yuan, Ying; Zhou, Xiaohua

2014-11-01

188

ceramic  

NASA Astrophysics Data System (ADS)

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

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

2014-09-01

189

Ceramics  

NASA Astrophysics Data System (ADS)

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

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

2014-11-01

190

Ceramics  

NASA Astrophysics Data System (ADS)

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

Panigrahi, M. R.

2014-09-01

191

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

PubMed

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

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

2009-03-01

192

AN EXPERIMENTAL STUDY OF SPHERICAL INDENTATION ON PIEZOELECTRIC MATERIALS  

E-print Network

AN EXPERIMENTAL STUDY OF SPHERICAL INDENTATION ON PIEZOELECTRIC MATERIALS U. RAMAMURTY{, S. SRIDHAR) AbstractÐThe response of lead zirconate titanate and barium titanate piezoelectric ceramics to spherical) for the spheri- cal indentation of a transversely isotropic piezoelectric material. A parametric analysis

Suresh, Subra

193

Continuous cross-over from ferroelectric to relaxor state and piezoelectric properties of BaTiO3-BaZrO3-CaTiO3 single crystals  

NASA Astrophysics Data System (ADS)

Optimal properties like piezoelectricity can be found in polarizable materials for which the structure changes sharply under small composition variations in the vicinity of their morphotropic phase boundary or the triple point in their isobaric temperature-composition phase diagram. In the latter, lead-free (Ba0.850Ca0.150)(Ti0.900Zr0.100)O3 ceramics exhibit outstanding piezoelectric coefficients. For the first time, we report the growth of piezoelectric lead-free single crystals in the BaTiO3-BaZrO3-CaTiO3 pseudo-ternary system. The stoichiometry control in the CaO-BaO-TiO2-ZrO2 solid solution led to single crystals with various compositions ranging from (Ba0.857Ca0.143)(Ti0.928Zr0.072)O3 to (Ba0.953Ca0.047)(Ti0.427Zr0.573)O3. We evidenced a continuous cross-over from a ferroelectric state at high titanium content to a relaxor one on increasing the zirconium content. Such a property tuning is rather seldom observed in lead-free ferroelectrics and confirms what was already reported for ceramics. Single crystal with (Ba0.838Ca0.162)(Ti0.854Zr0.146)O3 composition, which has been grown and oriented along [001] crystallographic direction, displayed electromechanical coefficients d31 and k31 of 93 pC.N-1 and 0.18, respectively, near the room temperature (T = 305 K).

Benabdallah, F.; Veber, P.; Prakasam, M.; Viraphong, O.; Shimamura, K.; Maglione, M.

2014-04-01

194

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

PubMed

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

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

2014-03-01

195

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

NASA Astrophysics Data System (ADS)

An enhancement for magnetoelectric (ME) effects is studied in a three-phase ME architecture consisting of two magnetostrictive Terfenol-D (Tb0.3Dy0.7Fe1.92) plates, a piezoelectric PZT (Pb(Zr,Ti)O3) plate, and a pair of shape-optimized FeCuNbSiB nanocrystalline alloys. By modifying the conventional shape of the magnetic flux concentrator, the shape-optimized flux concentrator has an improved effective permeability (?eff) due to the shape-induced demagnetizing effect at its end surface. The flux concentrator concentrates and amplifies the external magnetic flux into Terfenol-D plate by means of changing its internal flux concentrating manner. Consequently, more flux lines can be uniformly concentrated into Terfenol-D plates. The effective piezomagnetic coefficients (d33m) of Terfenol-D plate and the ME voltage coefficients (?ME) can be further improved under a lower magnetic bias field. The dynamic magneto-elastic properties and the effective magnetic induction of Terfenol-D are taken into account to derive the enhanced effective ME voltage coefficients (?ME,eff), the consistency of experimental results and theoretical analyses verifies this enhancement. The experimental results demonstrate that the maximum d33m in our proposed architecture achieves 22.48 nm/A under a bias of 114 Oe. The maximum ?ME in the bias magnetic range 0-900 Oe reaches 84.73 mV/Oe under the low frequency of 1 kHz, and 2.996 V/Oe under the resonance frequency of 102.3 kHz, respectively. It exhibits a 1.43 times larger piezomagnetic coefficient and a 1.87 times higher ME voltage coefficient under a smaller magnetic bias of 82 Oe than those of a conventional Terfenol-D/PZT/Terfenol-D composite. These shape-induced magnetoelectric behaviors provide the possibility of using this ME architecture in ultra-sensitive magnetic sensors.

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

2014-03-01

196

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

197

Lead-Free Propellant for Propellant Actuated Devices  

NASA Technical Reports Server (NTRS)

Naval Surface Warfare Center, Indian Head Division's CAD/PAD Department has been working to remove toxic compounds from our products for about a decade. In 1992, we embarked on an effort to develop a lead-free double base propellant to replace that of a foreign sole source. At the time there were availability concerns. In 1995, the department developed a strategic proposal to include a wider range of products. Efforts included such efforts as removing lead sheathing from linear explosives and replacing lead azide and lead styphnate compounds. This paper will discuss efforts specifically related to developing non-leaded double base propellant for use in various Propellant Actuated Devices (PADs) for aircrew escape systems. The propellants can replace their leaded counterparts, mitigating lead handling, processing, or toxic exposure to the environment and personnel. This work eliminates the use of leaded compounds, replacing them with a more environmentally benign metal-organic salt. Historically double-base propellants have held an advantage over other families of energetic materials through their relative insensitivity of the burning rate to changes in temperature and pressure. This desirable ballistic effect has been obtained with the use of a lead-organic salt alone or in a physical mixture with a copper-organic salt, or more recently with a lead-copper complex. These ballistic modifiers are typically added to the double-base 'paste' prior to gelatinization on heated calendars or one type or another. The effect of constant burning rate over a pressure range is called a 'plateau' while an even more beneficial effect of decreasing burning rate with increasing pressure is termed a 'mesa.' The latter effect results in very low temperature sensitivity of the propellant burning rate. Propellants with such effects are ideal tactical rocket motor propellants. The use of lead compounds poses a concern for the environment and personnel safety due to the metal's toxic nature when introduced into the atmosphere by propellant manufacturing, rocket firings, and disposal. Two separate programs are underway at Indian Head to replace the leaded ballistic modifiers in NOSIH-AA-2 and KU propellants. Although the system requirements were very different, the programs gained valuable information from one another throughout their course.

Goodwin, John L.

2000-01-01

198

Mitigation of thermal and fatigue behavior in K0.5Na0.5NbO3-based lead free piezoceramics  

PubMed Central

K0.5Na0.5NbO3-(KNN) based lead free materials have been found to exhibit good piezoelectric properties (d33?250 pC?N) due to the orthorhombic-tetragonal polymorphic phase transition (PPT) temperature compositionally shifted downward to near room temperature. However, associated with the PPT are issues of temperature and domain instability, making them impractical for applications. In this work, CaTiO3 (CT) was used to effectively shift the PPT downward in effort to mitigate these issues. As expected, CT modified KNN based materials exhibited nearly temperature independent properties (?50?200 C) and fatigue-free behavior, together with its relatively high d33 value of ?200 pC?N, make the CT modified KNN based materials excellent candidates for lead free actuators and transducers. PMID:19479047

Zhang, Shujun; Xia, Ru; Hao, Hua; Liu, Hanxing; Shrout, Thomas R.

2008-01-01

199

Effect of ENIG deposition on the failure mechanisms of thermomechanically loaded lead-free 2nd level interconnections in LTCC\\/PWB assemblies  

Microsoft Academic Search

Purpose The purpose of this paper is to investigate the effect of electroless NiAu (ENIG) deposition on the failure mechanisms and characteristic lifetimes of three different non-collapsible lead-free 2nd level interconnections in low-temperature co-fired ceramic (LTCC)\\/printed wiring board (PWB) assemblies. Design\\/methodology\\/approach Five LTCC module\\/PWB assemblies were fabricated and exposed to a temperature cycling test over a ?40 to

O. Nousiainen; T. Kangasvieri; K. Kautio; R. Rautioaho; J. Vhkangas

2010-01-01

200

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

201

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

PubMed

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

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

2013-11-13

202

A role of BNLT compound addition on structure and properties of PZT ceramics  

NASA Astrophysics Data System (ADS)

In this research, effects of lead-free bismuth sodium lanthanum titanate (BNLT) addition on structure and properties of lead zirconate titanate (PZT) ceramics were investigated. PZT ceramics with addition of 0.1-3.0 wt%BNLT were fabricated by a solid-state mixed oxide method and sintering at 1050-1200 C for 2 h to obtain dense ceramics with at least 96% of theoretical density. X-ray diffraction indicated that complete solid solution occurred for all compositions. Phase identification showed both tetragonal and rhombohedral perovskite structure of PZT with no BNLT phase detected. Scanning electron micrographs of fractured PZT/BNLT ceramics showed equiaxed grain shape with both transgranular and intergranular fracture modes. Addition of BNLT was also found to reduce densification and effectively limited grain growth of PZT ceramic. Optimum Hv and KIC values were found to be 4.85 GPa and 1.56 MPa.m 1/2 for PZT/0.5 wt%BNLT sample. Among PZT/BNLT samples, room temperature dielectric constant seemed to be improved with increasing BNLT content. The maximum piezoelectric coefficient values were observed in pure PZT ceramic and were slightly decreased in BNLT-added samples. Small reduction of remanent polarization and coercive field in hysteresis loops was observed in BNLT-added samples, indicating a slightly suppressed ferroelectric interaction in this material system.

Jaita, P.; Watcharapasorn, A.; Jiansirisomboon, S.

2010-09-01

203

A study on the disk-shaped piezoelectric transformer with multiple outputs.  

PubMed

In this study, a modified disk-shaped multiple-output piezoelectric transformer operated at the fundamental radial vibration mode has been presented. A derived equivalent circuit for the multioutput piezoelectric transformer was used to analyze the performance. Two piezoelectric transformers, a symmetrically electroded piezoelectric transformer with dual outputs and an asymmetrically electroded piezoelectric transformer with triple outputs, were fabricated with lead zirconate titanate piezoelectric ceramics. The characteristics of the two piezoelectric transformers were investigated experimentally. The piezoelectric transformer with multiple outputs has potential to be used in power supply units and other electronic circuits. PMID:18163745

Guo, Mingsen; Lam, K H; Wang, S; Kwok, K W; Chan, Helen L W; Zhao, X Z

2007-12-01

204

LEAD FREE METALLISATION FOR SILICON SOLAR CELLS: RESULTS FROM THE EC2CONTACT PROJECT  

Microsoft Academic Search

This paper reports the successful development of lead free thick film metallisation pastes for contacting crystalline silicon solar cells, as performed in the EC2Contact project. Due to detailed characterization, we now understand the process of contact formation of front side metallisation pastes to silicon. New test procedures have reduced the number of experiments. Silver pastes with lead free glass frits

Jaap Hoornstra; Gunnar Schubert; Ccile LePrince; Gerhard Wahl; Kees Broek; Filip Granek; Beate Lenkeit; Jrg Horzel; ASSOCIATED EXPERIMENTS

205

The effect of melting time on lead-free solder strength  

Microsoft Academic Search

In this test, the effect of melting time on reflow soldering of lead-free solder was investigated. Lead-free solders, which had been qualified in a previous test, were used. The production window for the melting time was investigated. As is known, the melting time for solder joints should not be too short since this may cause cold joints. On the other

Kari Maattanen; Jouko Happonen; Aulis Tuominen

2001-01-01

206

Thermal Fatigue Assessment of Lead-Free Solder Joints Qiang YU and Masaki SHIRATORI  

E-print Network

Thermal Fatigue Assessment of Lead-Free Solder Joints Qiang YU and Masaki SHIRATORI Department@swan.me.ynu.ac.jp ABSTRACT In this paper the authors have investigated the thermal fatigue reliability of lead-free solder on the initiation and propagation behaviors of fatigue cracks. Furthermore, they also studied the effect of voids

Paris-Sud XI, Université de

207

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

Microsoft Academic Search

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

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

2004-01-01

208

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

NASA Astrophysics Data System (ADS)

Ceramics, as broadly defined, include all materials other than organic substances and metals, either crystalline or amorphous. They have been used by humans since early history and have contributed considerably to improving the quality of our life. In most cases, however, high-temperature treatment is necessary to prepare ceramics. This burdens the environment and there is therefore a great need for new ceramics processing methods. Recent technologically advanced ceramics are often composed of nanocrystallites, which have great potential for innovation in terms of exploring practical applications of nanomaterials and, consequently, reducing the environmental load. The ceramics industry had long flourished in Asia, particularly in East Asia, and even today, this region is leading the development of related materials. In line with these traditions, Japanese and Korean ceramics societies have been co-sponsoring seminars on ceramics since the 1980s. Having become more international in scope and context, a series of these seminars is now known as the International Japan-Korea Seminar on Ceramics. This focus issue contains eight key articles presented at the 26th International Japan-Korea Seminar on Ceramics held on 24-26 November 2010 at the Tsukuba International Congress Center. In particular, Fabbri et al review electrode materials for protonic solid-oxide fuel cells, and Kamiya et al outline the present situation and future prospects for transparent transistors, particularly those based on amorphous In-Ga-Zn-O films. Eitel et al discuss the progress in engineering high-strain lead-free piezoelectric ceramics. Kim and Kumar review a simple processing method for producing porous ceramics using polysiloxane precursors, Kamiya and Iijima focus on surface modification and characterization of nanomaterials, and Wan et al briefly review the strategy of reducing lattice thermal conductivity of thermoelectric materials and propose new materials for thermoelectric devices. Aubert et al introduce a novel technique of synthesizing composite nanomaterials and Cross and coworkers characterize Pb(Zr,Ti)O3 (PZT) ferroelectric thin films co-doped with Bi and Fe to enhance PZT capacitor ferroelectric properties. These articles are closely related to the global environmental load and energy issues that require solutions in modern ceramics technology. We hope that this focus issue will help advance not only ceramics-related but also other fields of materials science.

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

2010-10-01

209

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

NASA Astrophysics Data System (ADS)

We have previously described sintered Na0.5Bi0.5TiO3-Bi12TiO20 composites as flexoelectric-type polar ceramics because they have a net macroscopic flexoelectric polarization. Here, we report on the universal existence of the macroscopic flexoelectric polarization in the (Na0.5Bi0.5)1-xSrxTiO3-Bi12TiO20 system, in which enhanced piezoelectricity is observed. By combining Raman spectroscopy and x-ray photoelectron spectroscopy techniques, we have identified the local flexoelectric polarization as distorted BiO5 polyhedra and TiO6 octahedra in the SrTiO3-Bi12TiO20 ceramic. The macroscopic polarization may be due to the partial alignment of these distorted units located within the grain boundary amorphous phases. Bi12TiO20 could have an important role in these flexoelectric-type polar ceramics.

Wang, L. H.; Zhao, M. L.; Wang, C. L.; Wang, J.; Kuai, W. J.; Tao, X. T.

2012-08-01

210

1662 Piezoelectric Microdispenser  

E-print Network

using the high-temperature flux technique is a notable example of another approach. For ceramic materials, there are many approaches available to a researcher for fabrication, including the simple pellet press, tape casting, screen printing, sputter deposition (especially PZT and ZnO), sol-gel techniques for thin films, pulsed-laser deposition, and the hygrothermal technique [10] for deposition of quality PZT onto titanium. Key Research Findings During World War II, the discovery of PZT was a fortuitous and remarkable improvement on the state of the art in piezoelectric materials engineering. Since then, modest improvements in performance of piezoelectric materials have been made, with the discovery of single-crystal high-strain PMN-PT materials [8] an important milestone.

unknown authors

211

Electrical Power Generation Using Piezoelectric Crystal  

E-print Network

Abstract- The usefulness of most high technology devices such as cell phones, computers, and sensors is limited by the storage capacity of batteries. In the future, these limitations will become more pronounced as the demand for wireless power outpaces battery development which is already nearly optimized. Thus, new power generation techniques are required for the next generation of wearable computers, wireless sensors, and autonomous systems to be feasible. Piezoelectric materials are excellent power generation devices because of their ability to couple mechanical and electrical properties. For example, when an electric field is applied to piezoelectric a strain is generated and the material is deformed. Consequently, when a piezoelectric is strained it produces an electric field; therefore, piezoelectric materials can convert ambient vibration into electrical power. Piezoelectric materials have long been used as sensors and actuators; however their use as electrical generators is less established. A piezoelectric power generator has great potential for some remote applications such as in vivo sensors, embedded MEMS devices, and distributed networking. Developing piezoelectric generators is challenging because of their poor source characteristics (high voltage, low current, high impedance) and relatively low power output. This paper presents a theoretical analysis to increase the piezoelectric power generation that is verified with experimental results. Index Terms-Piezoelectric materials, piezoelectricity, power generation, PZT ceramics.

unknown authors

212

Piezoelectric properties in soft-hard pseudobinary system  

Microsoft Academic Search

Pb(Zr, Ti)O3 Ceramics added with Pb(Sb1\\/2Nb1\\/2)O3 (PSN) or Pb(Mn1\\/3Nb2\\/3)O3 (PMN) ceramics behave like soft and hard piezoelectric materials, respectively. Variety in piezoelectric properties is obtained in the pseudobinary system constituted by PZT-PSN and PZT-PMN ceramics. Compositions having both high Kp and Qm values are prepared. An enhancement in piezoelectric activity is found when the composition is rich in hard material

Syh-Yuh Cheng; Chien-Min Wang; Shu-Fen Liao

1990-01-01

213

Piezoelectric Driver for Incremental Motion  

NASA Technical Reports Server (NTRS)

Vibrating device containing two piezoelectric ceramic slabs acts as mechanical driver. Eventually substitutes for small continuous or stepping electric motors of slow to moderate speeds. Piezoelectric driver simple in construction, requires no precise dimensions, inexpensive to make, and needs no lubrication. Not damaged by stalling or overloads and safe for use in explosive atmospheres; Motion controllable in micron-size increments, and holds position when power turned off. Potential applications as positioner or mover. Used to position instrument pointers, antennas, or solar panels; to focus lenses; or operate tuners, recording instruments, or valves.

Bruman, Joseph R.

1987-01-01

214

Comprehensive investigation of elastic and electrical properties of Li/Ta-modified (K,Na)NbO3 lead-free piezoceramics  

NASA Astrophysics Data System (ADS)

A full set of elastic and electrical coefficients of (K,Na)NbO3-based lead-free piezoceramics with a nominal composition of Li0.03(K0.48Na0.52)0.97(Nb0.8Ta0.2)O3 (abbreviated as KNNLT) was evaluated by the standard resonance method, and compared to those of K4CuNb8O23 doped (K0.45Na0.55)NbO3 (KNN-KCN) as well as typical Pb(Zr,Ti)O3-based piezoceramics PZT5A. The measurement of intermediate elastic stiffness and compliance coefficients of KNNLT indicated that KNNLT is elastically "softer" than KNN-KCN but "harder" than PZT5A. An extremely high piezoelectric stiffness coefficient h33 = 68.8 108 V/m was obtained, due to an especially low clamped dielectric constant ?33S of 361. And a large longitudinal electromechanical coupling factor k33 = 57% was observed in the KNNLT system. Furthermore, the piezoelectric coefficient d33 of KNNLT was characterized via three distinctive methods: the resonance method, the Berlincourt method, and the converse piezoelectric strain measurement; while these three techniques yielded values of 174 pC/N, 195 pC/N, and 308 pm/V, respectively. The difference in d33 values determined by the three methods may be attributed to different measurement frequencies and extrinsic piezoelectric contributions related to domain wall vibration and domain switching. Besides, the piezoelectric performances of KNNLT piezoceramics were found insensitive to frequency but susceptible to temperature and electric field cycling.

Yao, Fang-Zhou; Wang, Ke; Li, Jing-Feng

2013-05-01

215

Reliability study of surface mount printed circuit board assemblies with lead-free solder joints  

Microsoft Academic Search

Purpose The purpose of this paper is to evaluate the lead-free solder joint reliability of a variety of surface mount components assembled onto printed circuit boards (PCBs) under a number of different tests. Design\\/methodology\\/approach Lead-free solder with a composition of Sn96.5-Ag3.0-Cu0.5 was used in a surface mount reflow process. Different types of surface mount dummy components with a

Jeffery C. C. Lo; B. F. Jia; Z. Liu; J. Zhu; S. W. Ricky Lee

2008-01-01

216

Surface activation process of lead-free solder bumps for low temperature bonding  

Microsoft Academic Search

Focused on the problems of the lead-free alloys bonding at high melting temperature, high density, low cost and low temperature lead-free flip chip bonding process was developed by the surface activated bonding (SAB) method. Sn-3.0Ag-0.5Cu (wt %) alloy, with better reliability and solderability than other alternatives for electronic packaging, were chose for the experiments to be bonded with typical electrodes,

YingHui Wang; Kenji Nishida; Matthias Hutter; Matiar R Howlader; Eiji Higurashi; T. Suga; T. Kimura

2005-01-01

217

Electrochemical migration of Sn-Pb and lead free solder alloys under distilled water  

Microsoft Academic Search

Electrochemical migration (ECM) is a potential reliability problem in electronic soldering which might become more dangerous\\u000a in lead free electronic devices. In this paper, electrochemical migration tests on Sn-Pb and lead free solder alloys were\\u000a conducted under distilled water by applying constant voltages with a power supply. The susceptibility of the solder alloys\\u000a to ECM and the effect of the

D. Q. Yu; W. Jillek; E. Schmitt

2006-01-01

218

Piezoelectric Film.  

ERIC Educational Resources Information Center

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

Garrison, Steve

1992-01-01

219

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

Microsoft Academic Search

Porous Li0.06(Na0.5K0.5)0.94NbO3 (LNKN-6) ceramics with different pore volumes have been prepared using preceramic powder and phenol resin fiber (KynolTM) as a pore former. It was confirmed that the porous ceramics synthesized by the ``two-stage firing method'' suppressed the loss of alkali elements from the porous body during heat treatment. The porous LNKN-6 ceramics were then converted to LNKN-6\\/KNbO3 composites through

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

2007-01-01

220

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

221

Piezoelectric Energy Harvester for Batteryless Switch Devices  

NASA Astrophysics Data System (ADS)

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

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

2013-10-01

222

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

Microsoft Academic Search

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

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

2009-01-01

223

Pre-stressed Curved Actuators: Characterization and Modeling of their Piezoelectric Behavior  

E-print Network

Pre-stressed Curved Actuators: Characterization and Modeling of their Piezoelectric Behavior Karla actuators consist of a piezoelectric ceramic (lead zirconate titanate or PZT) sandwiched between various-stressed piezoelectric devices are of interest in a variety of aerospace applications. Their performance as a function

224

5H-2 A Piezoelectric Membrane Sensor for Biomedical Monitoring  

Microsoft Academic Search

A piezoelectric membrane sensor, consisting of a metal foil, a piezoelectric ceramic film and a top electrode, has been developed. Thick lead zirconate titanate composite film was coated onto a stainless steel (SS) foil and a top electrode was formed using a silver paste. The SS foil served as the bottom electrode as well as the substrate. Due to the

Y. Ono; Q. Liu; M. Kobayashi; C.-K. Jen; A. Blouin

2006-01-01

225

Acoustic to Electric Energy Conversion Using Piezoelectric Transducers  

Microsoft Academic Search

Presented is an analysis of a piezoelectric transduction system and a comparison to experimental data. A mathematical model is used to compare the external electric effects of an electric energy conversion system using piezoelectric ceramic transducers. The energy conversion is from electric to mechanical and back to electric. The transduction system is modeled by an electromechanical circuit in which electrical

Joel Marcus Hall

1993-01-01

226

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

NASA Astrophysics Data System (ADS)

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

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

2009-10-01

227

Estimation Method for Liquidus Temperature of Lead-Free Solder Using Differential Scanning Calorimetry Profiles  

NASA Astrophysics Data System (ADS)

It is usually complicated to analyze the liquidus temperature of lead-free solder, because unlike Sn-Pb eutectic solder, supercooling easily occurs during the cooling process of lead-free solder, and common lead-free solders contain only a small fraction of a primary phase. In order to determine the melting temperature range of lead-free solder easily, an estimation method using differential scanning calorimetry (DSC) profiles is proposed. The purpose of this study is to show the applicability of the newly proposed DSC-based approach. DSC profiles using several heating rates were measured and analyzed. As a result, it was found that the extrapolated onset temperature, the peak temperature, and the extrapolated end temperature of the endothermic peak were proportional to the square root of the DSC heating rate. For lower heating rate, the temperature-axis intercept of the relationship between the square root of the heating rate and the peak temperature can be regarded as the liquidus temperature under equilibrium conditions with better accuracy. For higher heating rate, the temperature-axis intercept of the relationship between the square root of the heating rate and the extrapolated end temperature can be approximately estimated as the liquidus temperature of noneutectic lead-free solder under equilibrium conditions.

Nishikawa, Hiroshi; Hamada, Yoshihito; Takemoto, Tadashi

2009-12-01

228

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

NASA Astrophysics Data System (ADS)

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

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

2014-06-01

229

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

230

Assembly of lead-free bumped flip-chip with no-flow underfills  

Microsoft Academic Search

Lead-free solder reflow process has presented challenges to no-flow underfill material and assembly. The currently available no-flow underfill materials are mainly designed for eutectic Sn-Pb solders. This paper presents the assembly of lead-free bumped flip-chip with developed no-flow underfill materials. Epoxy resin\\/HMPA\\/metal AcAc\\/Flux G system is developed as no-flow underfills for Sn\\/Ag\\/Cu alloy bumped flip-chips. The solder wetting test is

Zhuqing Zhang; C. P. Wong

2002-01-01

231

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

232

Lead free metallisation paste for crystalline silicon solar cells: from model to results  

Microsoft Academic Search

This work reports successful development of thick film lead free metallisation paste for contacting crystalline silicon solar cells. Models have been set-up to understand and describe the process of contact formation and current transport of front side metallisation pastes to silicon. New experimental test procedures have been developed to assess the models and minimize the number of experimental tests. The

Jaap Hoornstra; Gunnar Schubert; Kees Broek; Filip Granek; Ccile LePrince

2005-01-01

233

Coarsening processes in the lead-free solder alloy AgCu: theoretical and experimental investigations  

Microsoft Academic Search

Experimental investigations show that the microstructure of solders changes over time. In order to estimate the reliability and the lifetime of microelectronic solder materials it is important to predict the rate of microstructural change. Starting with an experimentally based overview on nucleation, spinodal decomposition as well as subsequent phase growth as observed in (lead-free) microelectronic solder connections this paper concentrates

W. H. Muller; T. Bohme

2005-01-01

234

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

Microsoft Academic Search

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

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

2011-01-01

235

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...

236

Mechanical fatigue reliability of PBGA assemblies with lead-free solder and halogen-free PCBs  

Microsoft Academic Search

In order to comply with the environmental legislations in Europe (WEEE) and Japan and to capture the market share in 'green' products, electronics manufacturers are beginning to introduce lead-free solder and halogen-free PCBs into their products. The change of materials impacts the entire manufacturing supply chain, from component and solders material suppliers to assembly equipment vendors. The industry has identified

Krishna Jonnalagadda; Fangjuan Qi; Jim Liu

2004-01-01

237

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

238

Thermomigration: An experimental damage mechanics study on nanoelectronic lead free solder alloys  

Microsoft Academic Search

This dissertation focuses on experimental study of thermomigration in lead-free solder alloys. Thermomigration in microelectronic solder joints was not a concern until significant miniaturization of electronics devices required to run high current densities with smaller solder joint sizes. High current density induces electromigration and Joule heating at the same time. The imbalance of Joule heating generated at top and bottom

Mohd Foad Abdul Hamid

2008-01-01

239

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...

240

Silver glues and lead-free alloys in die attach of power devices  

Microsoft Academic Search

Environmental, health and safety regulatory, as well as consumer pressure, have pushed industry to remove lead from electronic products. Soft solders used for die bonding (die attach) is the more critical for replacing. The increasing of peak temperature that the packages must withstand limits the number of commercially competitive alloys that can be use as lead free solders for die

L. Gobbato; A. Scandurra; Tong Yan Tee

2005-01-01

241

3D Study of Thermal Stresses in Lead-Free Surface Mount Devices  

Microsoft Academic Search

The paper presents the study of non-uniform temperature distributions in a flip chip electronic assembly, and the use of these temperature distributions to analyse the thermal stresses in lead-free solder joints in surface mount devices. The thermal stresses in the solder joints are mainly due to the mismatch in the coefficients of thermal expansions between the component and substrate materials,

Pradeep Hegde; David Whalley; Vadim V. Silberschmidt

2008-01-01

242

Board level drop test and simulation of leaded and lead-free BGA-PCB assembly  

Microsoft Academic Search

Leaded and lead-free ball grid array (BGA) components were tested in board level drop test defined in the Joint Electron Device Engineering Council (JEDEC) standard under different load levels. Finite element analysis (FEA) models were established using ANSYS. The stress and strain in the solder joint and the average strain energy density (SED) in the solderpad interface accumulated in one

Xin Qu; Zhaoyi Chen; Bo Qi; Taekoo Lee; Jiaji Wang

2007-01-01

243

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

NASA Technical Reports Server (NTRS)

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

Brown, Christina

2004-01-01

244

Piezoelectric Properties of Polycrystalline Lead Titanate Zirconate Compositions  

Microsoft Academic Search

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

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

1960-01-01

245

Piezoelectric paint sensor for real-time structural health monitoring  

NASA Astrophysics Data System (ADS)

Sensors, which collect data for further information processing, are core component of any viable structural health monitoring system. Continuous on-line structural health monitoring can be achieved through the use of advanced sensors developed for real-time structural health monitoring applications. To overcome the problems associated with traditional piezoelectric ceramics, a polymer-based piezoelectric paint material has been developed and recently used for sensors. The piezoelectric paint is composed of tiny piezoelectric particles mixed within polymer matrix and therefore belongs to "0-3" piezoelectric composite. Because of the electro-mechanical coupling properties of piezoelectric paint, the dynamic responses of host structures can be monitored by measuring the output voltage signals from the piezoelectric paint sensor. Piezoelectric paint sensors hold a great potential for dynamic strain sensing applications due to the ease with which their mechanical properties can be adjusted, low fabrication cost, ease of implementation, and conformability to curved surface Additionally, a novel surface crack detection technique has been conceived and validated experimentally, in which cracks of the host structure is detected by observing the measured signals from an piezoelectric paint sensor with multi-electrode configuration. This paper presents this piezoelectric paint-based crack monitoring method as well as validation test data. The piezoelectric paint sensor is ideal for surface crack detection in locations with complex geometry, such as welded joints, which conventional sensors are ill equipped to do.

Zhang, Yunfeng

2005-05-01

246

Evaluation of Ferroelectric Properties of Piezoelectric Ceramics Based on Crystallographic Homogenization Method and Crystal Orientation Analysis by SEMEBSD Technique  

NASA Astrophysics Data System (ADS)

Macroscopic ferroelectric properties of piezoelectric polycrystals are strongly affected by microscopic inhomogeneous crystal structure. In our previous study, a multi-scale finite element method based on crystallographic homogenization method has been developed to estimate macroscopic properties considering microscopic crystal morphology. In this paper, the crystal orientation distribution of polycrystalline barium titanate has been measured by SEMEBSD technique, and the measured crystal orientation distribution has been introduced to the microscopic finite element model. As the prediction of macroscopic properties depends on the sampling conditions of the measured crystal orientations, the effects of number of sampling points and sampling area have been investigated. As a result, the effective sampling conditions have been clarified to estimate macroscopic ferroelectric properties.

Uetsuji, Yasutomo; Yoshida, Toshihiro; Yamakawa, Takayuki; Tsuchiya, Kazuyoshi; Ueda, Sei; Nakamachi, Eiji

247

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

NASA Astrophysics Data System (ADS)

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

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

2013-07-01

248

Cosmic ray modulation studies with Lead-free Gulmarg neutron monitor  

E-print Network

A lead-free neutron monitor operating at High Altitude Research Laboratory (HARL), Gulmarg optimized for detecting 2.45 MeV neutron bursts produced during the atmospheric lightning discharges is also concurrently used for studying background neutron component present in the atmosphere. These background neutrons are produced due to the interaction of primary cosmic rays with the atmospheric constituents. In order to study and extract the information about the yield of the neutron production during transient atmospheric lightning discharges, the system is continuously operated to monitor and record the cosmic ray produced background secondary neutrons in the atmosphere. The data analysis of the background neutrons recorded by Lead-Free Gulmarg Neutron Monitor (LFGNM) has convincingly established that the modulation effects due to solar activity phenomena compare very well with those monitored by the worldwide IGY or NM64 type neutron monitors which have optimum energy response relatively towards the higher ener...

Darzi, M A; Mir, T A; Mufti, S; Shah, G N

2014-01-01

249

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

Microsoft Academic Search

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

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

2005-01-01

250

Drop impact life prediction model for lead-free BGA packages and modules  

Microsoft Academic Search

System-in-package (SiP) such as multi-chip or stacked die BGA modules with wirebond, flip-chip or hybrid interconnect are getting popular for advanced packaging applications. The design of SiP is more dependent on modeling as the package structure and failure mechanism are too complicated to be studied. It is known that drop impact reliability of lead-free BGA solder joints is a critical

Jing-en Luan; Tong Yan Tee; Kim Yong Goh; Hun Shen Ng; Xavier Baraton; Robert Bronner; Marika Sorrieul; Esa Hussa; Tommi Reinikainen; Arni Kujala

2005-01-01

251

Predictive modeling and experimental validation of lead-free solder joint reliability under temperature cycling  

Microsoft Academic Search

This study serves to validate the predictive finite element modeling approach for the solder joint thermal fatigue life analysis, with emphasis on the applicability to various lead-free solder joints. The three packages involved in the study are 8??8 mm PBGA, l0??l0 mm QFN, and 51??51 mm CBGA. They are designed to consist of SAC387, SAC305, SAC305 ball + SAC387 paste

Y. S. Chan; F. Song; C. C. J. Lo; E. Lee; S. Lee

2010-01-01

252

Mechanical bend fatigue reliability of lead-free and halogen-free PBGA assemblies  

Microsoft Academic Search

In order to comply with impending legislative regulations in Europe (WEEE) and Japan and meet market demand for environmentally friendly products, electronics manufacturers are beginning to introduce lead-free solder and halogen-free PCBs into their products. The change of materials impacts the entire manufacturing supply chain, from component and solder-material suppliers to assembly equipment vendors. The manufacturability and reliability of several

Krishna Jonnalagadda; Fangjuan Qi; Jim Liu

2005-01-01

253

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

254

Experimental investigation on the failure of lead-free solder joints under drop impact  

Microsoft Academic Search

Purpose The purpose of this paper is to investigate the mechanism of ball grid array (BGA) lead-free solder joint failure under board-level drop impact. Design\\/methodology\\/approach A round shaped test board was used. First, drop tests at three different heights were carried out. Then, dye stain testing and metallurgical analysis were performed in order to study the failure mechanism

Fang Liu; Guang Meng; Mei Zhao

2010-01-01

255

Performance Evaluation for Electrical Plate Lead-free Solder Bumping on Sapphire Wafers  

Microsoft Academic Search

Electrical plating lead-free solder bumping process is quite common for silicon wafers in semiconductor industry, while for sapphire wafers there are still some technical issues to be encountered. Bumped wafer of unreasonable bumping structure has always been found bumps knocked-off after wafer singulation process which is a three-point breaking. Triple higher residual stress may be accumulated on sapphire wafer surface

Y. J. Zhiyuan

2007-01-01

256

Impression creep testing and microstructurally adaptive creep modeling of lead free solder interconnects  

Microsoft Academic Search

Creep plays an important role in the reliability of solder joints under thermo-mechanical fatigue conditions encountered by a microelectronic package during service. In addition, the fine intermetallic precipitates (Ag3Sn and\\/or Cu6Sn5) in the microstructures of the new lead-free solders (Sn-Ag and Sn-Ag-Cu) can undergo significant in situ strain-enhanced coarsening during TMC, resulting in in-service evolution of the creep behavior of

I. Dutta; D. Pan; S. Jadhav

2005-01-01

257

Investigations of all lead free IGBT module structure with low thermal resistance and high reliability  

Microsoft Academic Search

This paper presents all lead free IGBT module structure with low thermal resistance and high reliability. Using thick copper foil alumina DCB, Sn\\/Ag\\/In solder, and copper base, we have achieved low thermal resistance as same as the current aluminum nitride (AlN) IGBT module structure. In addition to low thermal resistance, this new structure shows excellent temperature cycling capability of 3000

Y. Nishimura; A. Morozumi; E. Mochizuki; Y. Takahashi

2006-01-01

258

Logistics for the implementation of lead-free solders on electronic assemblies  

SciTech Connect

The prospects of legislative and regulatory action aimed at taxing, restricting or banning lead-bearing materials from manufactured products has prompted the electronics community to examine the implementation of lead-free solders to replace currently used lead-containing alloys in the manufacture of electronic devices and assemblies. The logistics for changing the well established ``tin-lead solder technology`` require not only the selection of new compositions but also the qualification of different surface finishes and manufacturing processes. The meniscometer/wetting balance technique was used to evaluate the wettability of several candidate lead-free solders as well as to establish windows on processing parameters so as to facilitate prototype manufacturing. Electroplated and electroless 100Sn coatings, as well as organic preservatives, were also examined as potential alternative finishes for device leads and terminations as well as circuit board conductor surfaces to replace traditional tin-lead layers. Sandia National Laboratories and AT&T have implemented a program to qualify the manufacturing feasibility of surface mount prototype circuit boards using several commercial lead-free solders by infrared reflow technology.

Vianco, P.T. [Sandia National Labs., Albuquerque, NM (United States); Artaki, I. [AT and T Bell Labs., Princeton, NJ (United States). Engineering Research Center

1993-12-31

259

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

E-print Network

Proceedings of the 2007 Aging Aircraft Conference Cost Model for Assessing the Transition to Lead the cost ramifications of the transition from tin- lead to lead-free electronic parts. All tin-lead, all lead-free and mixed assembly approaches are considered. The model makes basic assumptions of a fixed

Sandborn, Peter

260

Piezoelectric Effect  

NSDL National Science Digital Library

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

2008-10-23

261

Diffuse phase transition in Li{sub 0.12}Na{sub 0.88}NbO{sub 3} piezoelectric ceramics  

SciTech Connect

The morphotropic phase boundary composition viz. lithium sodium niobate, Li{sub 0.12}Na{sub 0.88}NbO{sub 3}, (LNN-12) was prepared by conventional solid state reaction and sintering route. The temperature dependent permittivity response near transition temperature showed a diffused phase transition (DPT). The degree of diffuseness, {gamma}, using the modified Curie-Weiss law, was found to be 1.92, indicative of almost-complete diffuse phase transition. The planar coupling constant k{sub p}, and mechanical quality factor Q{sub m}, measured by resonance-antiresonance method, were 0.17 and 413 respectively. These parameter values make LNN-12 ceramic an attractive candidate for transducers applications.

Mitra, Supratim; Kulkarni, Ajit R.; Prakash, Om [Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology Bombay, Mumbai 400076 (India)

2013-02-05

262

Creep and rupture behavior of Cu wire\\/lead-free solder-alloy joint specimen  

Microsoft Academic Search

Creep and rupture behavior of Cu wire\\/lead-free solder-alloy joint specimens have been investigated using Sn-3.5% Ag and Sn-0.5%\\u000a Cu alloys. A Sn-37% Pb solder alloy is also used as a reference material. The present authors have fabricated a creep-rupture\\u000a testing machine for Cu wire\\/solder-alloy joint specimens, performed creep and rupture tests at 303 K and 403 K, analyzed the\\u000a characteristics

Kepeng Wu; Makoto Aoyama; Noboru Wade; Jie Cui; Shinji Yamada; Kazuya Miyahara

2003-01-01

263

Design and characterization of piezoelectric ultrasonic motors  

NASA Astrophysics Data System (ADS)

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

Yener, Serra

264

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

265

Cosmic ray modulation studies with Lead-free Gulmarg neutron monitor  

E-print Network

A lead-free neutron monitor operating at High Altitude Research Laboratory (HARL), Gulmarg optimized for detecting 2.45 MeV neutron bursts produced during the atmospheric lightning discharges is also concurrently used for studying background neutron component present in the atmosphere. These background neutrons are produced due to the interaction of primary cosmic rays with the atmospheric constituents. In order to study and extract the information about the yield of the neutron production during transient atmospheric lightning discharges, the system is continuously operated to monitor and record the cosmic ray produced background secondary neutrons in the atmosphere. The data analysis of the background neutrons recorded by Lead-Free Gulmarg Neutron Monitor (LFGNM) has convincingly established that the modulation effects due to solar activity phenomena compare very well with those monitored by the worldwide IGY or NM64 type neutron monitors which have optimum energy response relatively towards the higher energy regime of the cosmic rays. The data has revealed various types of modulation phenomena like diurnal variation, Forbush decrease etc. during its entire operational period. However, a new kind of a periodic/seasonal variation pattern is also revealed in the data from September 2007 to September 2012, which is seen to be significantly consistent with the data recorded by Emilio Segre observatory, Israel (ESOI) Neutron Monitor. Interestingly, both these neutron monitors have comparable latitude and altitude. However, the same type of consistency is not observed in the data recorded by the other conventional neutron monitors operating across the globe.

M. A. Darzi; P. M. Ishtiaq; T. A. Mir; S. Mufti; G. N. Shah

2013-12-21

266

Trapped thickness-twist modes in an inhomogeneous piezoelectric plate  

NASA Astrophysics Data System (ADS)

We show the existence of certain thickness-twist modes in an unbounded, inhomogeneous piezoelectric plate of crystals with 6-mm symmetry or in polarized ceramics. The modes found are trapped, with the vibration confined to a portion of the plate. These modes are exact and satisfy the three-dimensional equations of piezoelectricity. Potentially, they can be used as the operating modes of plate resonators and acoustic wave sensors, in particular, thin film resonators of ZnO and AlN.

Yang, J.; Chen, Z.; Hu, Y.

2006-11-01

267

Health hazards of ceramic artists.  

PubMed

Ceramic artists can be exposed to many hazards including metals (such as lead), fibrogenic dusts (such as silica), heat, repetitive motion, radiation, and toxic emissions from kilns. The health risks of these exposures have not been well characterized among artists, although limited information is available from commercial potteries. Adverse health effects may be prevented by using less hazardous materials (such as lead-free glazes), improved ventilation, and proper work practices. Special precautions must be in place if children have access to the ceramics studio. The use of glazed ceramic dishes can be a risk for lead toxicity. Food should not be stored in glazed ceramics, and pregnant women should avoid daily use of ceramic mugs for drinking hot beverages. PMID:11567917

Dorevitch, S; Babin, A

2001-01-01

268

Calibration of piezoelectric positioning actuators using a reference voltage-to-displacement transducer based on quartz tuning forks  

E-print Network

We use a piezoelectric quartz tuning fork to calibrate the displacement of ceramic piezoelectric scanners which are widely employed in scanning probe microscopy. We measure the static piezoelectric response of a quartz tuning fork and find it to be highly linear, non-hysteretic and with negligible creep. These performance characteristics, close to those of an ideal transducer, make quartz transducers superior to ceramic piezoelectric actuators. Furthermore, quartz actuators in the form of a tuning fork have the advantage of yielding static displacements comparable to those of local probe microscope scanners. We use the static displacement of a quartz tuning fork as a reference to calibrate the three axis displacement of a ceramic piezoelectric scanner. Although this calibration technique is a non-traceable method, it can be more versatile than using calibration grids because it enables to characterize the linear and non-linear response of a piezoelectric scanner in a broad range of displacements, spanning fro...

Castellanos-Gomez, Andres; Agrat, Nicols; Rubio-Bollinger, Gabino; 10.1017/S1431927611012839

2012-01-01

269

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

270

Electrical and thermal conductivities and thermopower of some lead free solders (LFS) in the liquid and solid state  

Microsoft Academic Search

We have measured the electrical resistivity and thermopower of industrial liquid and solid leadtin alloys and of several lead free solders (SnAg; SnCu; SnSb; SnAgCu), and have deduced the thermal conductivity as a function of the temperature by using the relations between the electronic transport coefficients. The resistivity of lead free solders are smaller than those of leadtin alloys, which

S. Mhiaoui; F. Sar; J. G. Gasser

2007-01-01

271

Performance testing of lead free primers: blast waves, velocity variations, and environmental testing  

E-print Network

Results are presented for lead free primers based on diazodinitrophenol (DDNP)compared with tests on lead styphnate based primers. First, barrel friction measurements in 5.56 mm NATO are presented. Second, shot to shot variations in blast waves are presented as determined by detonating primers in a 7.62x51mm rifle chamber with a firing pin, but without any powder or bullet loaded and measuring the blast wave at the muzzle with a high speed pressure transducer. Third, variations in primer blast waves, muzzle velocities, and ignition delay are presented after environmental conditioning (150 days) for two lead based and two DDNP based primers under cold and dry (-25 deg C,0% relative humidity), ambient (20 deg C, 50% relative humidity), and hot & humid (50 deg C, 100% relative humidity) conditions in 5.56 mm NATO. Taken together, these results indicate that DDNP based primers are not sufficiently reliable for service use.

Courtney, Elya; Summer, Peter David; Courtney, Michael

2014-01-01

272

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.

273

Optical properties of lead-free oxyfluoride germanate glasses doped with Pr3+  

NASA Astrophysics Data System (ADS)

Optical properties of Pr3+ ions in lead-free germanate glasses modified by BaF2 were investigated. Luminescence bands related to 3P0 ? 3H4, 3P0 ? 3H5, 1D2 ? 3H4, 3P0 ? 3H6, 3P0 ? 3F2 transitions of Pr3+ were registered under 450 nm excitation. The relative integrated luminescence intensities of 3P0 ? 3H4 transition (blue) to the 3P0 ? 3F2 transition (red) of Pr3+ ions strongly depend on fluoride modifier BaF2 in glass composition. The blue-to-red luminescence intensity ratios of Pr3+ are drastically reduced, when BaO is partially substituted by BaF2. The luminescence lines due to 3P0 ? 3F2 hypersensitive transition of Pr3+ are blue shifted with increasing BaF2 concentration.

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

2014-05-01

274

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

NASA Astrophysics Data System (ADS)

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

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

2012-07-01

275

"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

276

Piezoelectric Crystals: Future Source  

E-print Network

With the increase in energy consumption due to evergrowing number of electronic devices, the concept of harvesting renewable energy in human surrounding arouses a renewed interest. In this context, we have highlighted use of piezoelectricity and its generation. The other alternative thought is shared at the end. Key words Mechanical pressure, piezoelectric effect, piezoelectric, material, ferroelectrics, crystals thermocouple. I.

unknown authors

277

Evaluation technique for the failure life scatter of lead-free solder joints in electronic device  

Microsoft Academic Search

Recently, the electronic device equipments using a lot of semiconductors are widespread to all industrial fields. Solder joints are used to mount the electronic chips, such as ceramic resistors and capacitors, on the printed-circuit boards in almost all electronic devices. However, since in many cases the thermal expansion coefficients of electronic parts and PCBs have mismatch, cyclic thermal stress and

H. Miyauchi; Qiang Yu; T. Shibutani; M. Shiratori

2007-01-01

278

Design and implementation of a versatile and variable-frequency piezoelectric coefficient measurement system.  

PubMed

We present a simple but versatile piezoelectric coefficient measurement system, which can measure the longitudinal and transverse piezoelectric coefficients in the pressing and bending modes, respectively, at different applied forces and a wide range of frequencies. The functionality of this measurement system has been demonstrated on three samples, including a PbZr(0.52)Ti(0.48)O(3) (PZT) piezoelectric ceramic bulk, a ZnO thin film, and a laminated piezoelectric film sensor. The static longitudinal piezoelectric coefficients of the PZT bulk and the ZnO film are estimated to be around 210 and 8.1 pC/N, respectively. The static transverse piezoelectric coefficients of the ZnO film and the piezoelectric film sensor are determined to be, respectively, -0.284 and -0.031 C/m(2). PMID:22938335

Wu, J S; Huang, Y K; Wu, F L; Lin, D Y

2012-08-01

279

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

NASA Astrophysics Data System (ADS)

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

Zhou, Bite

280

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

281

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

2014-11-01

282

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

283

Thermomigration: An experimental damage mechanics study on nanoelectronic lead free solder alloys  

NASA Astrophysics Data System (ADS)

This dissertation focuses on experimental study of thermomigration in lead-free solder alloys. Thermomigration in microelectronic solder joints was not a concern until significant miniaturization of electronics devices required to run high current densities with smaller solder joint sizes. High current density induces electromigration and Joule heating at the same time. The imbalance of Joule heating generated at top and bottom of solder joint causes a temperature gradient which is large enough to induce thermomigration damage. In the literature, most studies report electromigration induced damage without considering the influence of thermomigration, thus the effect of electromigration and thermomigration can not be individually identified. This dissertation studies the experimental damage mechanics of thermomigration without electromigration by studying formation and destruction of intermetallic compound, and vacancy migration due to diffusion driving forces. Microstructural degradation and hardness testing were used to quantify thermomigration induced damage. After studying material science and physics behind the thermomigration process, using test vehicles, the combined effects of electromigration and thermomigration were studied experimentally. The studies were repeated at a subzero temperatures to see the effect of low temperature on thermomigration and electromigration, and reliability of nanoelectronic solder joints. A new time to failure equation is proposed to show a threshold temperature below which diffusion slows down significantly. By ensuring the solder operating temperature is well kept below the threshold value by proper thermal management, the solder joint life can be extended.

Abdul Hamid, Mohd Foad

284

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

285

The Measurement of Thermal Conductivity Variation with Temperature for Sn-Based Lead-Free Binary Solders  

NASA Astrophysics Data System (ADS)

The variations of thermal conductivity with temperature in the Sn-based lead-free binary solders, Sn-10 wt pct X (X = Ag, In, Bi, Cu, Sb, Zn), were measured by using the linear heat flow apparatus. The thermal conductivities of Sn-based lead-free solders at their melting temperature were obtained from graphs of thermal conductivity variation with temperature. The variations of electrical conductivity with temperature for same solders were also determined from the Wiedemann-Franz (W-F) equation by using the measured values of thermal conductivity.

Demir, Mustafa; Aksz, Sezen; ztrk, Esra; Mara?l?, Necmettin

2014-10-01

286

Mechanical properties study of lead free solder joint material used in semiconductor packaging subjected to thermal condition  

Microsoft Academic Search

The effect of high temperature storage (HTS) on lead free solder joint material for ball grid array application using pull test method were studied in this paper. Some statistical analysis base on the pull test data also discussed. Three samples of different lead free solder joint material were selected in this experiment namely Sn3.8Ag0.7Cu (SAC387), Sn2.3Ag0.08Ni0.01Co (SANC), and Sn3.5Ag. After

M. Najib Harif; Ibrahim Ahmad

2010-01-01

287

Development of novel piezoelectric composites by solid freeform fabrication techniques  

Microsoft Academic Search

Piezoelectric ceramic\\/polymer composites have been widely used for ultrasonic transducers because of their superior properties as compared to bulk piezoceramics or polymers. The electromechanical Properties of the composites can be tailored for various applications by changing the design and connectivity of the piezoceramic skeleton. The goal of this project was to utilize the design flexibility provided by solid freeform fabrication

Rajesh Kumar Panda

1998-01-01

288

Consideration of impedance matching techniques for efficient piezoelectric energy harvesting.  

PubMed

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

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

2007-09-01

289

Switchable static friction of piezoelectric compositesilicon wafer contacts  

NASA Astrophysics Data System (ADS)

The meso-scale surface roughness of piezoelectric fiber composites can be manipulated by applying an electric field to a piezocomposite with a polished surface. In the absence of an applied voltage, the tips of the embedded piezoelectric ceramic fibers are below the surface of the piezocomposite and a silicon wafer counter surface rests solely on the matrix region of the piezocomposite surface. When actuated, the piezoelectric ceramic fibers protrude from the surface and the wafer rests solely on these protrusions. A threefold decrease in engineering static friction coefficient upon actuation of the piezocomposite was observed: from ?* = 1.65 to ?* = 0.50. These experimental results could be linked to the change in contact surface area and roughness using capillary adhesion theory, which relates the adhesive force to the number and size of the contacting asperities for the different surface states.

van den Ende, D. A.; Fischer, H. R.; Groen, W. A.; van der Zwaag, S.

2013-04-01

290

Piezoelectric properties of polyamide 11/NaNbO3 nanowire composites  

NASA Astrophysics Data System (ADS)

Polyamide 11(PA 11)/sodium niobate nanowire (NW) 0-3 composites with different volume fractions of NWs were synthesized. The electric polarization (P) was measured as a function of the applied electric field (E). The P-E hysteresis loop was used to work out the remanent polarization Pr of these materials. The dielectric permittivity and the piezoelectric strain constant were determined. Good impedance matching between inorganic and organic phases leads to higher electroactivity than conventional lead-free 0-3 composites. The piezoelectric voltage of the PA 11/NaNbO3 NW composites is of the same order as those obtained for fluorinated piezoelectric polymers. These composites could have some applications in flexible, low-cost, environmentally friendly piezoelectric sensors and actuators.

David, Charlotte; Capsal, Jean-Fabien; Laffont, Lydia; Dantras, Eric; Lacabanne, Colette

2012-10-01

291

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

SciTech Connect

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

Rohatgi, P.K.

1996-02-01

292

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

SciTech Connect

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

Rohatgi, P.K.

1995-07-01

293

Effects of thickness on the piezoelectric and dielectric properties of lead zirconate titanate thin films  

E-print Network

gauges, pressure transducers, and accelerometers. Bulk ferroelectric ceramic sensors have certain substrates by a sol-gel method and crystallized with preferred 111 or 100 orientation. Both the piezoelectric Ferroelectric ceramics have been employed extensively in a variety of sensors and actuators including strain

Sottos, Nancy R.

294

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

NASA Astrophysics Data System (ADS)

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

Yang, Cheng; Fritzen, Claus-Peter

2011-11-01

295

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

NASA Astrophysics Data System (ADS)

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

Yang, Cheng; Fritzen, Claus-Peter

2012-04-01

296

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

NASA Astrophysics Data System (ADS)

This contribution focuses on the use of modified Rayleigh law as a technique for determining the intrinsic and extrinsic (reversible/irreversible) contributions to the piezoelectric effect up to 150 C across a broad compositional space, augmenting previous understanding of the BiFeO3-(K0.5Bi0.5)TiO3-PbTiO3 system. At room temperature, a mechanistic explanation of the correlation between crystal symmetry, i.e., tetragonal spontaneous strain, xs, and the Rayleigh relations using Landau theory is provided. The intrinsic response was found to be heavily dependent upon the tetragonal xs, whereby an optimisation between polarization and permittivity was elucidated, leading to enhanced piezoelectric charge coefficients. A c/a ratio of 1.041 was identified at which the room temperature intrinsic and extrinsic effects were at a maximum; a dinit of 183 10-12 m/V and Rayleigh coefficient of 59 10-18 m2/V2 were measured, resulting in the largest piezoelectric charge coefficients. The piezoelectric charge coefficient d33, intrinsic and extrinsic contributions of these materials were all found to increase up to 150 C while adhering to the Rayleigh model. The reversible extrinsic component of the total reversible response, dinit, was calculated to be relatively minor, 4.9% at room temperature, increasing to 12.1% at 150 C, signifying its increasing influence to the piezoelectric effect, as domain wall motion is thermally activated. Hence, the phenomenological interpretation provided here may be used as a roadmap to elucidate the origins of the temperature dependence of the piezoelectric effect.

Bennett, J.; Shrout, T. R.; Zhang, S. J.; Mandal, P.; Bell, A. J.; Stevenson, T. J.; Comyn, T. P.

2014-09-01

297

Fabrication of piezoelectric fibers with metal core  

NASA Astrophysics Data System (ADS)

A study on the fabrication of Pb(Nb,Ni)O3-Pb(Zr,Ti)O3 (PNN-PZT) piezoelectric ceramic fibers with a metal core is introduced. The green fibers were fabricated by extruding a mixture of PNN-PZT powder and organic solvent together with a 50 mm Pt core. The fibers of 250 mm in diameter and a few centimeters long are obtained without any cracks after sintered at 1200C. The core is precisely located at the center of the fibers. The boundary of the PNN-PZT ceramics and the Pt core was investigated by cutting the fiber along the cross-section and the longitudinal direction, and observing them with a scanning electron microscope. The ferroelectricity and piezoelectricity of a single fiber was confirmed. The polarization versus electric field relationship was measured by a Radiant RT-6000 and the result exhibits the typical ferroelectricity of the PNN-PZT material. The strain versus electric field relationship also shows the typical hysteresis of piezoelectric materials due to the d31 effect.

Qiu, Jinhao; Tani, Junji; Yamada, Naoki; Takahashi, Hirofumi

2003-08-01

298

Wireless drive of piezoelectric components.  

E-print Network

??To widen the application range of piezoelectric devices, various new techniques including wireless drive of piezoelectric components by parallel plate capacitor structure, focused electric field, (more)

Satyanarayan Bhuyan.

2011-01-01

299

Newly developed real time monitoring system for ionic migration of lead-free solder by means of quartz crystal microbalance  

Microsoft Academic Search

To investigate the ionic migration, quite a new measurement method has been developed by the authors, which enables real timemonitoring of the growth process of ionic migration using a QCM (Quartz Crystal Microbalance). This research has focused on the QCM method to study the process of ion migration in various types of lead-free solder plating and the effects of the

S. Yoshihara; H. Tanaka; F. Ueta; K. Kumekawa; H. Hiramatsu

2001-01-01

300

Effect of the Molecular Weight of Dispersant to the Slurry for Lead-Free Transparent Dielectric Films  

Microsoft Academic Search

To manufacture a green sheet for the lead-free PDP transparent dielectric by tape casting method, the dispersion characteristics of the slurry prepared by different molecular weight of polymeric dispersant have been studied. The dispersion stability was enhanced as the molecular weight of a dispersant was lower. Rapid particle agglomeration occurred by bonding among of long polymer chains and it effected

Byung-Yong Wang; Dae-Soon Lim; Young-Jei Oh

2009-01-01

301

Thermal performance and microstructure of lead versus lead-free solder die attach interface in power device packages  

Microsoft Academic Search

Lead-free solders are being investigated as replacements for lead solders currently used in the power electronics industry. Currently, the eutectic lead-tin alloy is widely used for attaching power devices. Thermal performance of packaged power devices and multichip modules depends largely on the quality of the solder interface between the power semiconductor devices, such as MOSFETs, IGBTs and diodes, and the

Kelly Stinson-Bagby; Dan Huff; Dimos Katsis; Daan Van Wyk; G. Q. Lu

2004-01-01

302

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

303

Nonlinear dielectric response in piezoelectric materials for underwater transducers  

NASA Astrophysics Data System (ADS)

SONAR transducers based on single crystal lead magnesium niobate-lead titanate (PMNT) have demonstrated improvements over conventional lead zirconate titanate ceramics. Compositional modifications to PMNT have combined the high piezoelectric coefficient (d33 > 2000 pC/N) and electromechanical coupling factor (k33 > 0.90) with the low mechanical losses (QM > 1000) of "hard" piezoelectric ceramics. The dielectric losses of single crystal PMNT have not been investigated as extensively as the mechanical losses but may significantly affect the performance of a device when water loaded. In this work, nonlinearities in the dielectric permittivity and losses have been investigated as a function of applied electric field, measurement frequency, and temperature. It is shown that electromechanically "hard" single crystals offer greater stability of the dielectric properties while maintaining a high permittivity with respect to conventional lead zirconate titanate ceramics.

Sherlock, N. P.; Garten, L. M.; Zhang, S. J.; Shrout, T. R.; Meyer, R. J.

2012-12-01

304

Plates made of piezoelectric materials: when are they really piezoelectric?  

E-print Network

Plates made of piezoelectric materials: when are they really piezoelectric? Giuseppe Geymonat with the simplified but accurate modeling of linearly piezoelectric thin plates. It is shown how mathematical tools the fact that for some piezoelectric crystal classes, the coupling between the electrical

Boyer, Edmond

305

Piezoelectric angular acceleration sensor  

Microsoft Academic Search

This paper deals with a piezoelectric angular acceleration sensor, which might be proposed by us, first, as a new concept of the sensor to detect a rotational motion only. In the first part of this paper are dealt with some concrete constructions of this new concept of angular acceleration sensor, composed of piezoelectric transducers. The second part contains their basic

Y. Tomikawa; S. Okada

2003-01-01

306

Piezoelectric micromotors for microrobots  

Microsoft Academic Search

The authors have begun research into piezoelectric ultrasonic motors using ferroelectric thin films. The authors have fabricated the stator components of these millimeter diameter motors on silicon wafers. Ultrasonic motors consist of two pieces: a stator and a rotor. The stator includes a piezoelectric film in which bending is induced in the form of a traveling wave. A small glass

Anita M. Flynn; Lee S. Tavrow; Stephen F. Bart; Rodney A. Brooks; Daniel J. Ehrlich; K. R. Udayakumar; L. Eric Cross

1992-01-01

307

Microfabrication of Piezoelectric MEMS  

Microsoft Academic Search

In this chapter an overview of processes for fabrication of MEMS using piezoelectric thin films as active layer in planar structures is presented. These structures are used in cantilever-like and membrane configurations for sensing and actuation. Key issues consist in findings of a compatible dry etching sequence for piezoelectric layer, electrodes and silicon. The method of compensation of the gradient

J. Baborowski

308

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

309

Photostriction of SolGel Processed PLZT Ceramics  

Microsoft Academic Search

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

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

1997-01-01

310

Fabrication of lead zirconate titanate ceramic fibers by gelation of sodium alginate  

Microsoft Academic Search

A novel ceramic fiber processing method by gelation of Na-alginate, a natural innoxious polymer, is reported. The ion exchange reaction between Na and Ca, and associated gelation process is utilized to fabricate lead zirconate titanate piezoelectric ceramic fibers using a Na-alginate based ceramic suspension. Effects of solid loading, viscosity of the starting sodium alginate and its amount in the slurry,

Sedat Alkoy; Hakan Yanik; Bengu Yapar

2007-01-01

311

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

312

Investigation on electrical and microstructural properties of Thick Film Lead-Free resistor series under various firing conditions  

Microsoft Academic Search

The paper presents investigation of four lead free thick film resistor pastes, developed at ITME, denoted R-100, R-1k, R-10k\\u000a and R-100k with sheet resistivities of 0.1, 1, 10 and 100k?\\/?, respectively. The resistors were based on RuO2 as the conductive phase. The aim of the work was to evaluate the influence of firing conditions of the resistive pastes on\\u000a a

Konrad Kie?basi?ski; Ma?gorzata Jakubowska; Anna M?o?niak; Marko Hrovat; Janez Holc; Darko Belavi?

2010-01-01

313

Microstructure development and electrical properties of RuO 2 -based lead-free thick film resistors  

Microsoft Academic Search

Lead-free thick film resistive compositions suitable for hybrid microelectronics were prepared. The compositions were made\\u000a with RuO2 as the conducting phase and bismuthate glasses. This blend of bismuthate glasses constitutes a suitable choice for avoiding\\u000a negative effects such as devitrification, bleeding out of the glass on alumina substrates, anomalous distribution of conductive\\u000a grains in the glassy matrix and phase separation

M. G. Busana; M. Prudenziati; J. Hormadaly

2006-01-01

314

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

Microsoft Academic Search

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

Xiran Su; Haiping Luo; D. G. Yang

2006-01-01

315

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 Sn\\/Ag\\/Cu has resulted in higher temperature exposures during assembly compared with traditional eutectic Sn\\/Pb solders. Variations, if any, in laminate material properties before and after board assembly should be considered in the selection of appropriate laminates. This paper provides guidelines for laminate selection that are

Ravikumar Sanapala; Bhanu Sood; Diganta Das; Michael Pecht; C. Y. Huang; M. Y. Tsai

2008-01-01

316

Effect of cooling rate on Ag3Sn formation in SnAg based lead-free solder  

Microsoft Academic Search

Effect of solidification cooling rate on Ag3Sn formation and its morphological appearance in Sn-Ag based lead-free solder was investigated. Depends on cooling rate, three types of Ag3Sn compound with different morphologies may form by solidification. They are particle-like, needle-like, and platelike respectively. Small particle-like Ag3Sn in large amount was occurred by rapid cooling, where plate liked Ag3Sn was formed by

Hwa-Teng Lee; Yin-Fa Chen; Ting-Fu Hong; Ku-Ta Shih

2009-01-01

317

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

Microsoft Academic Search

To evaluate the current leakage and electrochemical migration behavior on printed circuit boards with eutectic tin-lead and lead-free solder, IPC B-24 comb structures were exposed to 65C and 88% relative humidity conditions under direct-current (DC) bias for over 1500 h. These boards were processed with either Sn-3.0Ag-0.5Cu solder or Sn-37Pb solder. In addition to solder alloy, board finish (organic solderability

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

2011-01-01

318

Designs of temperature loads on the fatigue life analysis of lead-free solder in IC packages  

Microsoft Academic Search

Firstly, finite element analysis software (ANSYS) is used to investigate the accumulated creep strain range and accumulated creep stain energy density properties of lead-free solder (95.5Sn-3.9Ag-0.6Cu) in IC packages under the temperature cyclic loading by the Garofalo-Arrhenius hyperbolic sine law. Then the Taguchi method is further used to analyze the effects of IC package models on the fatigue life subjected

W. R. Jong; H. C. Tsai; C. C. Lau

2009-01-01

319

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

320

Piezoelectricity of biopolymers.  

PubMed

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

Fukada, E

1995-01-01

321

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

322

Piezoelectric polymer multilayer on flexible substrate for energy harvesting.  

PubMed

A piezoelectric polymer multilayer structure formed on a flexible substrate is investigated for mechanical energy harvesting under bending mode. Analytical and numerical models are developed to clarify the effect of material parameters critical to the energy harvesting performance of the bending multilayer structure. It is shown that the maximum power is proportional to the square of the piezoelectric stress coefficient and the inverse of dielectric permittivity of the piezoelectric polymer. It is further found that a piezoelectric multilayer with thinner electrodes can generate more electric energy in bending mode. The effect of improved impedance matching in the multilayer polymer on energy output is remarkable. Comparisons between piezoelectric ceramic multilayers and polymer multilayers on flexible substrate are discussed. The fabrication of a P(VDF-TrFE) multilayer structure with a thin Al electrode layer is experimentally demonstrated by a scalable dip-coating process on a flexible aluminum substrate. The results indicate that it is feasible to produce a piezoelectric polymer multilayer structure on flexible substrate for harvesting mechanical energy applicable for many low-power electronics. PMID:24658732

Zhang, Lei; Oh, Sharon Roslyn; Wong, Ting Chong; Tan, Chin Yaw; Yao, Kui

2013-09-01

323

(K0.44,Na0.52,Li0.04)(Nb0.84,Ta0.10,Sb0.06)O3 ferroelectric ceramics.  

PubMed

Recent progress in (K0.44, Na0.52, Li0.04)O3-based ceramics (KNN) with special emphasis on(K0.44,Na0.52,Li0.04)(Nb0.84,Ta0.10,Sb0.06)O3 (KNN-LT-LS) is reviewed concisely. The base KNN and its compositional derivatives are analyzed in terms of dopant-property relationships, which are then extended to the ternary derivatives. The effects of processing conditions such as humidity, precursor purity, and oxygen partial pressure during sintering are elaborated on from a phenomenological perspective. It is also shown that the spontaneous polarization is sensitive to the processing route chosen for synthesis (mixed oxide versus perovskite routes). Special attention is devoted to the discussion of the morphotropic phase boundary (MPB) dilemma in the KNN-LT-LS system, where it is shown that the origin of high piezoelectric activity is actually due to a polymorphic transition at room temperature. It is shown that prototype transducers based on pure and 1 mol% Ba2+ doped KNN-LT-LS exhibit performance metrics comparable to those fabricated using PZT-5H. Overall, KNNLT- LS ceramics show great promise for lead-free applications, although issues such as temperature dependence of properties and strong sensitivity to processing conditions remain as the 2 major challenges. PMID:19686974

Safari, Ahmad; Abazari, Maryam; Kerman, Kian; Marandian-Hagh, Nader; Akdo?an, E Koray

2009-08-01

324

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

E-print Network

a critical magnitude EF.2­10 The associated volume change at the phase transition has been explored as a mechanism for toughening the ceramic.11 Recently, it has been reported that some chemically modi- fied Pb. Exposure to a strong electric field transforms the ceramic into a metastable ferroelectric phase. Following

Hong, Wei

325

University of California, Irvine Environmental Health and Safety www.ehs.uci.edu Questions Call: (949) 824-6200 Version 1.0 Lead Free UCI  

E-print Network

: (949) 824-6200 Version 1.0 Lead Free UCI Autoclave Tape - Get the Lead Out Environmental Health risks of lead pollution, and Replace lead containing autoclave tape with lead-free autoclave tape for FREE. Autoclave tape used in some laboratories may contain levels of lead that exceed the hazardous

George, Steven C.

326

Portfolio: Ceramics.  

ERIC Educational Resources Information Center

Describes eight art activities using ceramics. Elementary students created ceramic tiles to depict ancient Egyptian and medieval European art, made ceramic cookie stamps, traced bisque plates on sketch paper, constructed clay room-tableaus, and designed clay relief masks. Secondary students pit-fired ceramic pots and designed ceramic Victorian

Hardy, Jane; And Others

1982-01-01

327

Piezoelectric-mechanical-acoustic couplings from a PZT-actuated vibrating beam and its sound radiation  

Microsoft Academic Search

This paper presents a finite element modelling of flexural actuation of an aluminium cantilever beam by two thin plates made of piezoelectric PZT-ceramic material. An analytical study describes the actuators as flexural wave-source into the beam that once excited radiates sound waves into the surrounding air. FEM-calculations of piezoelectric-mechanical-acoustic aspects correlated together are then conducted with ANSYS that has been

C. H. Nguyen; S. J. Pietrzko

2004-01-01

328

Piezoelectricmechanicalacoustic couplings from a PZT-actuated vibrating beam and its sound radiation  

Microsoft Academic Search

This paper presents a finite element modelling of flexural actuation of an aluminium cantilever beam by two thin plates made of piezoelectric PZT-ceramic material. An analytical study describes the actuators as flexural wave-source into the beam that once excited radiates sound waves into the surrounding air. FEM-calculations of piezoelectricmechanicalacoustic aspects correlated together are then conducted with ANSYS that has been

C. H. Nguyen; S. J. Pietrzko

2004-01-01

329

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

330

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

331

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

332

A novel drum piezoelectric-actuator  

NASA Astrophysics Data System (ADS)

This paper presents a large displacement, piezoelectric-metal structure actuator, named the piezoelectric drum actuator. The drum actuator consists of a short, thick-walled steel cylinder sandwiched by two thin composite disks, which are fabricated from a brass disk bonded with a piezoceramic disk. The piezoceramic disk, which is polarized in its thickness direction, has a large diameter thickness ratio, producing a large radial displacement under an applied voltage in the thickness, leading to a large transverse deflection of the composite disks in the drum. The drum (outer diameter: 12.0 mm) has a displacement that is about eight times larger than that of a cymbal actuator made with the same ceramic material and comparable dimensions under the same dc driving voltage of 270 V. The drum actuator also showed a large resonance displacement of 56.7 ?m under an ac voltage of 90 V. The effective piezoelectric charge coefficient d33 of the drum is about twice as large as that reported for the cymbal.

Sun, C. L.; Lam, K. H.; Chan, H. L. W.; Zhao, X.-Z.; Choy, C. L.

2006-09-01

333

Ceramic Lasers  

NASA Astrophysics Data System (ADS)

1. Introduction; 2. Solid-state laser processes and active materials; 3. Fabrication techniques for laser materials; 4. Experimental techniques (powder characteristics and synthesis of optical grade ceramics, effects of sintering aids, etc.); 5. Synthesis of the doped polycrystalline cubic sesquioxide ceramics; 6. Synthesis of Re (Nd) heavily doped YAG ceramics; 7. Optical scattering center in polycrystalline ceramics; 8. Advanced technology in ceramic (composite, fiber, single crystal by sintering method, etc.); 9. Current R&D status of ceramic lasers world wide; 10. Conclusions and future in ceramic technology; 11. Mechanical and thermal properties of the laser ceramics; 12. High-resolution optical spectroscopy and emission decay of doped ceramics; 13. Emission processes in doped ceramics; 14. Ceramic photonic materials; 15. Laser emission of ceramic materials; Index.

Ikesue, Akio; Aung, Yan Lin; Lupei, Voicu

2013-05-01

334

JOINT RIGIDITY ASSESSMENT WITH PIEZOELECTRIC WAFERS AND ACOUSTIC WAVES  

SciTech Connect

There has been an interest in the development of rapid deployment satellites. In a modular satellite design, different panels of specific functions can be pre-manufactured. The satellite can then be assembled and tested just prior to deployment. Traditional vibration testing is time-consuming and expensive. An alternative test method to evaluate the connection between two plates will be proposed. The method investigated and described employs piezoelectric wafers to induce and sense lamb waves in two aluminum plates, which were joined by steel brackets to form an 'L-Style' joint. Lamb wave behavior and piezoelectric material properties will be discussed; the experimental setup and results will be presented. A set of 4 piezoelectric ceramic wafers were used alternately as source and sensor. The energy transmitted was shown to correlate with a mechanical assessment of the joint, demonstrating that this method of testing is a feasible and reliable way to inspect the rigidity of joints.

Montoya, Angela C.; Maji, Arup K. [University of New Mexico, Department of Civil Engineering, Albuquerque, New Mexico, 87131 (United States)

2010-02-22

335

Electrical Properties and Power Considerations of a Piezoelectric Actuator  

NASA Technical Reports Server (NTRS)

This paper assesses the electrical characteristics of piezoelectric wafers for use in aeronautical applications such as active noise control in aircraft. Determination of capacitive behavior and power consumption is necessary to optimize the system configuration and to design efficient driving electronics. Empirical relations are developed from experimental data to predict the capacitance and loss tangent of a PZT5A ceramic as nonlinear functions of both applied peak voltage and driving frequency. Power consumed by the PZT is the rate of energy required to excite the piezoelectric system along with power dissipated due to dielectric loss and mechanical and structural damping. Overall power consumption is thus quantified as a function of peak applied voltage and driving frequency. It was demonstrated that by incorporating the variation of capacitance and power loss with voltage and frequency, satisfactory estimates of power requirements can be obtained. These relations allow general guidelines in selection and application of piezoelectric actuators and driving electronics for active control applications.

Jordan, T.; Ounaies, Z.; Tripp, J.; Tcheng, P.

1999-01-01

336

Micromachined piezoelectric acoustic transducers  

NASA Astrophysics Data System (ADS)

The feasibilities and functionalities of three different types of diaphragm-based piezoelectric MEMS acoustic transducers (produced by combining micromachining procedures with piezoelectric ZnO thin-film processing) have been successfully demonstrated for audio and ultrasound applications. They are based on a dome-shaped diaphragm, parylene-supported diaphragm and parylene-held cantilever-like diaphragm, and have been fabricated compatibly with an IC fabrication processing that allows a cost-effective mass production of the transducer elements. Dome-shaped-diaphragm piezoelectric acoustic transducers have successfully been fabricated on a 1.5 ?m thick silicon nitride diaphragm (2,000 ?m in radius, with a circular clamped boundary on a silicon substrate) with electrodes and piezoelectric ZnO film. Due to the 3- dimensional nature of a dome diaphragm, the dome- diaphragm transducer has a stress-releasing capability and generates the high frequency sound effectively. The transducer's sound output (measured with B&K 4135 microphone 2 mm away from the transducer) is 70-113 dB SPL in 10-200 kHz ranges. We have successfully fabricated piezoelectric acoustic transducers built on 1.5 ?m thick parylene diaphragms (both flat 5,000*5,000 ?m 2 square diaphragm and dome-shaped 2,000 ?m-radius diaphragm with circular clamped boundary on a silicon substrate) with electrodes and piezoelectric ZnO film. Parylene-held cantilever-like diaphragm acoustic transducers have been fabricated and demonstrated to release the residual stress (and also to make the diaphragm mechanically flexible) much like a cantilever, and yet is itself a diaphragm with its four edges clamped. We have successfully fabricated and tested various piezoelectric acoustic transducers built on a silicon nitride layer (either in cantilever form and/or freely-suspended island form) with electrodes and piezoelectric ZnO film. Finite element modeling (FEM) is used to simulate the responses of the three different types of the micromachined acoustic transducers based on a piezoelectric active component. Full three-dimensional elements are used to model the piezoelectric acoustic transducers because such devices are not only anisotropic, but also couple electric and elastic fields, and satisfy the boundary conditions of the two fields independently. The finite element analysis accounts for the interaction (coupling) between electric and structural fields.

Han, Cheol-Hyun

337

Process for producing gasoline of high octane number and particularly lead free gasoline, from olefininc c3-c4 cuts  

SciTech Connect

Lead free gasoline of high octane number is obtained from C/sub 3/ and C/sub 4/ olefinic cuts as follows: propylene contained in the C/sub 3/ cut is oligomerized, at least 80% of the isobutene and less than 40% of the n-butenes of the C/sub 4/ cut are oligomerized to form an oligomerizate distilling in the gasoline range, which is separated from the unreacted C/sub 4/ hydrocarbons, the latter are subsequently alkylated to form a gasoline fraction which can be admixed with the oligomerizates of the Cnumber and the C/sub 4/ cuts to produce the desired high octane gasoline.

Hellin, M.; Juguin, B.; Torck, B.; Vu, Q. D.

1981-05-19

338

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

Microsoft Academic Search

To evaluate the current leakage and electrochemical migration behavior on printed circuit boards with eutectic tin-lead and\\u000a lead-free solder, IPC B-24 comb structures were exposed to 65C and 88% relative humidity conditions under direct-current\\u000a (DC) bias for over 1500h. These boards were processed with either Sn-3.0Ag-0.5Cu solder or Sn-37Pb solder. In addition to\\u000a solder alloy, board finish (organic solderability preservative

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

2011-01-01

339

3D Piezoelectric Structures Made by Ink-Jet Printing  

Microsoft Academic Search

The purpose of this paper is to report the potential interest to develop piezoelectric structures by taking advantage both of the adaptive electromechanical behavior of 0.9PbMg 1\\/3 Nb 2\\/3 O 3 (PMN)-0.1PbTiO 3 (PT) ceramics and of the characteristics of rapid prototyping methods. In fact, as the piezo-activity of 0.9PMN-0.1PT ceramics is adjustable via the amplitude of the electric field;

Gautier Senlis; Matthieu Dubarry; Martine Lejeune; Thierry Chartier

2002-01-01

340

Direct piezoelectric responses of soft composite fiber mats  

NASA Astrophysics Data System (ADS)

Recently soft fiber mats electrospun from solutions of Barium Titanate (BT) ferroelectric ceramics particles and polylactic acid (PLA) were found to have large (d33 1 nm/V) converse piezoelectric signals offering a myriad of applications ranging from active implants to smart textiles. Here, we report direct piezoelectric measurements (electric signals due to mechanical stress) of the BT/PLA composite fiber mats at several BT concentrations. A homemade testing apparatus provided AC stresses in the 50 Hz-1.5 kHz-frequency range. The piezoelectric constant d33 0.5 nC/N and the compression modulus Y 104-105 Pa found are in agreement with the prior converse piezoelectric and compressibility measurements. Importantly, the direct piezoelectric signal is large enough to power a small LCD by simple finger tapping of a 0.15 mm thick 2-cm2 area mat. We propose using these mats in active Braille cells and in liquid crystal writing tablets.

Varga, M.; Morvan, J.; Diorio, N.; Buyuktanir, E.; Harden, J.; West, J. L.; Jkli, A.

2013-04-01

341

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

342

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

343

High-throughput evaluation of domain switching in piezoelectric ceramics and application to PbZr{sub 0.6}Ti{sub 0.4}O{sub 3} doped with La and Fe  

SciTech Connect

A combinatorial material synthesis and characterization technique is introduced and demonstrated wherein the ferroelectric behavior of a compositionally graded bulk ceramic is investigated during electrical loading. Using combined high-energy x-ray microdiffraction and fluorescence spectroscopy, non-180 deg. domain wall motion of different compositions is measured and quantified as a function of composition across the gradation. The greatest amount of non-180 deg. domain wall motion is found in samples containing the highest measured fraction of La dopant (2 mol %)

Jones, Jacob L.; Pramanick, Abhijit [Materials Science and Engineering, University of Florida, Gainesville, Florida 32611-6400 (United States); Daniels, John E. [European Synchrotron Radiation Facility (ESRF), 38043 Grenoble (France)

2008-10-13

344

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

345

Diaphragm Pump With Resonant Piezoelectric Drive  

NASA Technical Reports Server (NTRS)

A diaphragm pump driven by a piezoelectric actuator is undergoing development. This pump is intended to be a prototype of lightweight, highly reliable pumps for circulating cooling liquids in protective garments and high-power electronic circuits, and perhaps for some medical applications. The pump would be highly reliable because it would contain no sliding seals or bearings that could wear, the only parts subject to wear would be two check valves, and the diaphragm and other flexing parts could be designed, by use of proven methods, for extremely long life. Because the pump would be capable of a large volumetric flow rate and would have only a small dead volume, its operation would not be disrupted by ingestion of gas, and it could be started reliably under all conditions. The prior art includes a number piezoelectrically actuated diaphragm pumps. Because of the smallness of the motions of piezoelectric actuators (typical maximum strains only about 0.001), the volumetric flow rates of those pumps are much too small for typical cooling applications. In the pump now undergoing development, mechanical resonance would be utilized to amplify the motion generated by the piezoelectric actuator and thereby multiply the volumetric flow rate. The prime mover in this pump would be a stack of piezoelectric ceramic actuators, one end of which would be connected to a spring that would be part of a spring-and-mass resonator structure. The mass part of the resonator structure would include the pump diaphragm (see Figure 1). Contraction of the spring would draw the diaphragm to the left, causing the volume of the fluid chamber to increase and thereby causing fluid to flow into the chamber. Subsequent expansion of the spring would push the diaphragm to the right, causing the volume of the fluid chamber to decrease, and thereby expelling fluid from the chamber. The fluid would enter and leave the chamber through check valves. The piezoelectric stack would be driven electrically to make it oscillate at the resonance frequency of the spring and- mass structure. This frequency could be made high enough (of the order of 400 Hz) that the masses of all components could be made conveniently small. The resonance would amplify the relatively small motion of the piezoelectric stack (a stroke of the order of 10 m) to a diaphragm stroke of the order of 0.5 mm. The exact amplification factor would depend on the rate of damping of oscillations; this, in turn, would depend on details of design and operation, including (but not limited to) the desired pressure rise and volumetric flow rate. In order to obtain resonance with large displacement, the damping rate must be low enough that the energy imparted to the pumped fluid on each stroke is much less than the kinetic and potential energy exchanged between the mass and spring during each cycle of oscillation. To minimize the power demand of the pump, a highly efficient drive circuit would be used to excite the piezoelectric stack. This circuit (see Figure 2) would amount to a special-purpose regenerative, switching power supply that would operate in a power-source mode during the part of an oscillation cycle when the excitation waveform was positive and in a power-recovery mode during the part of the cycle when the excitation waveform was negative. The circuit would include a voltage-boosting dc-to-dc converter that would convert between a supply potential of 24 Vdc and the high voltage needed to drive the piezoelectric stack. Because of the power-recovery feature, the circuit would consume little power. It should be possible to build the circuit as a compact unit, using readily available components.

Izenson, Michael G.; Kline-Schoder, Robert J.; Shimko, Martin A.

2007-01-01

346

Tuning and parameter optimization of a digital integral controller for uniform droplet spray applications using lead-free tin-copper solder  

E-print Network

The advent of legislation restricting the use of lead in electronics requires innovation and refinement in processes for creating lead-free solder spheres for wafer bumping and other surface mount technology. Operation ...

De Castro, Eloisa M

2009-01-01

347

Induced piezoelectricity in isotropic biomaterial.  

PubMed

Isotropic material can be made to exhibit piezoelectric effects by the application of a constant electric field. For insulators, the piezoelectric strain constant is proportional to the applied electric field and for semiconductors, an additional out-of-phase component of piezoelectricity is proportional to the electric current density in the sample. The two induced coefficients are proportional to the strain-dependent dielectric constant (depsilon/dS + epsilon) and resistivity (drho/dS - rho), respectively. The latter is more important at frequencies such that rhoepsilonomega less than 1, often the case in biopolymers. Signals from induced piezoelectricity in nature may be larger than those from true piezoelectricity. PMID:990389

Zimmerman, R L

1976-12-01

348

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

349

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

2014-05-01

350

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

NASA Astrophysics Data System (ADS)

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

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

2011-09-01

351

Enhanced active piezoelectric 0-3 nanocomposites fabricated through electrospun nanowires  

SciTech Connect

The use of monolithic piezoceramic materials in sensing and actuation applications has become quite common over the past decade. However, these materials have several properties that limit their application in practical systems. These materials are very brittle due to the ceramic nature of the monolithic material, making them vulnerable to accidental breakage during handling and bonding procedures. In addition, they have very poor ability to conform to curved surfaces and result in large add-on mass associated with using a typically lead-based ceramic. These limitations have motivated the development of alternative methods of applying the piezoceramic material, including piezoceramic fiber composites and piezoelectric 0-3 composites (also known as piezoelectric paint). Piezoelectric paint is desirable because it can be spayed or painted on and can be used with abnormal surfaces. However, the piezoelectric paint developed in prior studies has resulted in low coupling, limiting its application. In order to increase the coupling of the piezoelectric paint, this effort has investigated the use of piezoelectric nanowires rather than spherical piezoelectric particle, which are difficult to strain when embedded in a polymer matrix. The piezoceramic wires were electrospun from a barium titanate (BaTiO{sub 3}) sol gel to produce fibers with 500-1000 nm diameters and subsequently calcinated to acquire perovskite BaTiO{sub 3}. An active nanocomposite paint was formed using the resulting piezoelectric wires and was compared to the same paint with piezoelectric nanoparticles. The results show that the piezoceramic wires produce 0-3 nanocomposites with as high as 300% increase in electromechanical coupling.

Feenstra, Joel [Department of Mechanical Engineering-Engineering Mechanics, Michigan Technological University, Houghton, Michigan 49931 (United States); Sodano, Henry A. [Department of Mechanical and Aerospace Engineering, Arizona State University, Tempe, Arizona 85287-6106 (United States)

2008-06-15

352

Full Piezoelectric Multilayer-Stacked Hybrid Actuation/Transduction Systems  

NASA Technical Reports Server (NTRS)

The Stacked HYBATS (Hybrid Actuation/Transduction system) demonstrates significantly enhanced electromechanical performance by using the cooperative contributions of the electromechanical responses of multilayer, stacked negative strain components and positive strain components. Both experimental and theoretical studies indicate that, for Stacked HYBATS, the displacement is over three times that of a same-sized conventional flextensional actuator/transducer. The coupled resonance mode between positive strain and negative strain components of Stacked HYBATS is much stronger than the resonance of a single element actuation only when the effective lengths of the two kinds of elements match each other. Compared with the previously invented hybrid actuation system (HYBAS), the multilayer Stacked HYBATS can be designed to provide high mechanical load capability, low voltage driving, and a highly effective piezoelectric constant. The negative strain component will contract, and the positive strain component will expand in the length directions when an electric field is applied on the device. The interaction between the two elements makes an enhanced motion along the Z direction for Stacked-HYBATS. In order to dominate the dynamic length of Stacked-HYBATS by the negative strain component, the area of the cross-section for the negative strain component will be much larger than the total cross-section areas of the two positive strain components. The transverse strain is negative and longitudinal strain positive in inorganic materials, such as ceramics/single crystals. Different piezoelectric multilayer stack configurations can make a piezoelectric ceramic/single-crystal multilayer stack exhibit negative strain or positive strain at a certain direction without increasing the applied voltage. The difference of this innovation from the HYBAS is that all the elements can be made from one-of-a-kind materials. Stacked HYBATS can provide an extremely effective piezoelectric constant at both resonance and off resonance frequencies. The effective piezoelectric constant can be alternated by varying the size of each component, the degree of the pre-curvature of the positive strain components, the thickness of each layer in the multilayer stacks, and the piezoelectric constant of the material used. Because all of the elements are piezoelectric components, Stacked HYBATS can serve as projector and receiver for underwater detection. The performance of this innovation can be enhanced by improving the piezoelectric properties.

Su, Ji; Jiang, Xiaoning; Zu, Tian-Bing

2011-01-01

353

Lead-free solder  

DOEpatents

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

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

2001-05-15

354

Microgeometry, piezoelectric sensitivity and anisotropy of properties in porous materials based on Pb(Zr, Ti)O3  

NASA Astrophysics Data System (ADS)

Relations between the microgeometry, piezoelectric sensitivity and piezoelectric anisotropy are studied in porous composite materials based on Pb(Zr, Ti)O3 ceramics. Systems of micrographs of cuts being parallel and perpendicular to the polarization direction are first shown for the porosity range vp = 0.05 - 0.57, and examples of microcracking at vp = 0.57 are considered. Experimental data on longitudinal and hydrostatic piezoelectric coefficients and squared figures of merit are represented as functions of vp, and nonmonotonic behavior of the piezoelectric anisotropy factor with increasing vp is analyzed in the context of changes in the microgeometry. Experimental results are compared to those derived from approximation formulae for the related porous ceramic.

Filippov, Sergei E.; Vorontsov, Alexander A.; Brill, Olga E.; Topolov, Vitaly Yu.

2014-03-01

355

Origin of piezoelectricity in monolayer halogenated graphane piezoelectrics  

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

356

Absolute measurement of in-plane vibrational distribution in piezoelectric resonators based on laser speckle interferometry  

Microsoft Academic Search

A full-field imaging method has been developed for rapidly measuring absolute in-plane vibrational distribution of piezoelectric devices. This method is based on the synchronized laser speckle method. To confirm the measurement accuracy, a quartz plate with a small mirror attached to a lateral surface is used. The plate is excited by an external ceramic vibrator, and the absolute vibrational displacement

Yasuaki Watanabe; Teruyoshi Tsuda; Sunao Ishii; Shigeyoshi Goka; Hitoshi Sekimoto

2005-01-01

357

On Ceramics.  

ERIC Educational Resources Information Center

Presents four ceramics activities for secondary-level art classes. Included are directions for primitive kiln construction and glaze making. Two ceramics design activities are described in which students make bizarrely-shaped lidded jars, feet, and footwear. (AM)

School Arts, 1982

1982-01-01

358

Fatigue failure kinetics and structural changes in lead-free interconnects due to mechanical and thermal cycling  

NASA Astrophysics Data System (ADS)

Environmental and human health concerns drove European parliament to mandate the Reduction of Hazardous Substances (RoHS) for electronics. This was enacted in July 2006 and has practically eliminated lead in solder interconnects. There is concern in the electronics packaging community because modern lead-free solder is rich in tin. Presently, near-eutectic tin-silver-copper solders are favored by industry. These solders are stiffer than the lead-tin near-eutectic alloys, have a higher melting temperature, fewer slip systems, and form intermetallic compounds (IMC) with Cu, Ni and Ag, each of which tend to have a negative effect on lifetime. In order to design more reliable interconnects, the experimental observation of cracking mechanisms is necessary for the correct application of existing theories. The goal of this research is to observe the failure modes resulting from mode II strain and to determine the damage mechanisms which describe fatigue failures in 95.5 Sn- 4.0 Ag - 0.5 Cu wt% (SAC405) lead-free solder interconnects. In this work the initiation sites and crack paths were characterized for SAC405 ball-grid array (BGA) interconnects with electroless-nickel immersion-gold (ENIG) pad-finish. The interconnects were arranged in a perimeter array and tested in fully assembled packages. Evaluation methods included monotonic and displacement controlled mechanical shear fatigue tests, and temperature cycling. The specimens were characterized using metallogaphy, including optical and electron microscopy as well as energy dispersive spectroscopy (EDS) and precise real-time electrical resistance structural health monitoring (SHM). In mechanical shear fatigue tests, strain was applied by the substrates, simulating dissimilar coefficients of thermal expansion (CTE) between the board and chip-carrier. This type of strain caused cracks to initiate in the soft Sn-rich solder and grow near the interface between the solder and intermetallic compounds (IMC). The growth near the interface was found to be caused by dislocation pile-ups at the IMC when the plastic zone ahead of the crack tip reached this interface. In temperature cycling testing, strains arose within the interconnect due to CTE mismatch between the solder and IMC. The substrates had matched CTE for all specimens in this research. Because of this, all the temperature cycling cracks were observed at interfaces, generally between the solder and IMC. Additionally, real-time electrical resistance may be a useful non-destructive evaluation (NDE) tool for the empirical observation of fatigue cracking in ball-grid arrays (BGA) during both mechanical and temperature cycling tests.

Fiedler, Brent Alan

359

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

NASA Astrophysics Data System (ADS)

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 1.5wt%, was investigated 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 such as tensile strength, 0.2% yield strength and the ultimate tensile strength and creep behavior of selected alloy compositions (Sn-4Ag-1.5Cu, Sn-4Ag-0.5Cu, Sn-2Ag-1.5Cu, Sn-2Ag-0.5Cu, Sn-3.5Ag-0.8Cu) were performed for three conditions: as-cast; aged for 100 hours at 125C; and aged for 250 hours at 125C. 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 will also be presented for the oil quenched samples. A hyperbolic-sine creep model was adopted and used to fit the creep experiment data. The effect of adding the quaternary element bismuth to the Sn-3.5Ag-0.8Cu alloy on the mechanical properties 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

360

1-4244-0665-X/06/$20.00 2006 IEEE 781 2006 Electronics Packaging Technology Conference Development of Life Prediction Model for Lead-free Solder at Chip Resistor  

E-print Network

of Life Prediction Model for Lead-free Solder at Chip Resistor Changwoon Han and Byeongsuk Song-mail : cw_han@keti.re.kr Abstract An accelerated thermal cycling test to assess the reliability of lead-free solders at chip resistor has been conducted. Test results indicate that the life of lead-free solder

Berlin,Technische Universität

361

Piezoelectric Actuator/Sensor Technology at Rockwell  

NASA Technical Reports Server (NTRS)

We describe the state-of-the art of piezoelectric materials based on perovskite and tungsten bronze families for sensor, actuator and smart structure applications. The microstructural defects in these materials have been eliminated to a large extent and the resulting materials exhibit exceedingly high performance for various applications. The performance of Rockwell actuators/sensors is at least 3 times better than commercially available products. These high performance actuators are being incorporated into various applications including, DOD, NASA and commercial. The multilayer actuator stacks fabricated from our piezoceramics are advantageous for sensing and high capacitance applications. In this presentation, we will describe the use of our high performance piezo-ceramics for actuators and sensors, including multilayer stacks and composite structures.

Neurgaonkar, Ratnakar R.

1996-01-01

362

Structural Ceramics  

NASA Technical Reports Server (NTRS)

This publication is a compilation of abstracts and slides of papers presented at the NASA Lewis Structural Ceramics Workshop. Collectively, these papers depict the scope of NASA Lewis' structural ceramics program. The technical areas include monolithic SiC and Si3N4 development, ceramic matrix composites, tribology, design methodology, nondestructive evaluation (NDE), fracture mechanics, and corrosion.

1986-01-01

363

A very promising piezoelectric property of Ta{sub 2}O{sub 5} thin films. II: Birefringence and piezoelectricity  

SciTech Connect

Birefringent and piezoelectric properties of Ta{sub 2}O{sub 5} ceramic thin films of monoclinic and trigonal structures were analyzed. The birefringence, observed by reflected polarized light microscopy, yields information on thin film microstructures, crystal shapes and sizes and on crystallographic orientations of grains of trigonal structure. Such an information was considered for investigating piezoelectric properties by laser Doppler vibrometry and by piezoresponse force microscopy. The vibration velocity was measured by applying an oscillating electric field between electrodes on both sides of a Ta{sub 2}O{sub 5} film deposited on a Si substrate which was pasted on an isolating mica sheet. In this case, it is shown that the vibration velocity results were not only from a converse piezoelectric effect, proportional to the voltage, but also from the Coulomb force, proportional to the square of the voltage. A huge piezoelectric strain effect, up to 7.6%, is found in the case of Ta{sub 2}O{sub 5} of trigonal structure. From an estimation of the electrical field through the Ta{sub 2}O{sub 5} thin film, this strain likely corresponds to a very high longitudinal coefficient d{sub 33} of several thousand picometers. Results obtained by piezoresponse force microscopy show that trigonal grains exhibit a polarization at zero field, which is probably due to stress caused expansion in the transition monoclinic-trigonal, presented in a previous article (part I). - Graphical abstract: Image of cross-polarized optical microscopy showing grains of trigonal structure embedded in the monoclinic phase (on the left); (a) mounting of the sample for Laser Doppler Vibrometry, sample constituted of several layers and its equivalent electrical circuit; (b) longitudinal displacements due to converse piezoelectric and Coulomb effects and corresponding piezoelectric strain-U{sub app.}. hystereses. Highlights: > A new Ta{sub 2}O{sub 5} trigonal phase is shown to be birefringent and piezoelectric. > This phase is related to a reversible transition with a monoclinic phase. > The piezoelectricity of this trigonal phase is of several thousands of pm/V. > It is compared to piezoelectricity of the monoclinic phase of several tens of pm/V.

Audier, M., E-mail: Marc.Audier@grenoble-inp.fr [Laboratoire des Materiaux et du Genie Physique, UMR CNRS 5628, Minatec - INP Grenoble, 3 parvis Louis Neel, BP 257, 38016 Grenoble Cedex 1 (France); Chenevier, B.; Roussel, H. [Laboratoire des Materiaux et du Genie Physique, UMR CNRS 5628, Minatec - INP Grenoble, 3 parvis Louis Neel, BP 257, 38016 Grenoble Cedex 1 (France); Vincent, L. [CIME Nanotech Minatec, Microsystemes et capteurs, F-38016 Grenoble Cedex 1 (France); Pena, A. [Institut Neel - CNRS/UJF, Dpt. Matiere Condensee, Materiaux et Fonctions, F-38042 Grenoble (France); Lintanf Salauen, A. [L2MA, CEA LETI D2NT, F-38054 Grenoble (France)

2011-08-15

364

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

365

Development of low-firing lead-free thick-film materials on steel alloys for piezoresistive sensor applications  

Microsoft Academic Search

Piezoresistive sensors based on steel and other metallic substrates provide higher strain response than on standard ceramic substrates and are more easily packaged. But exposing high-strength steels to the standard high-temperature 850degC thick-film firing cycle affects their mechanical properties. In previous studies, we have developed a range of low-firing thick-film materials based on lead borosilicate glass, which allows processing at

Caroline Jacq; Thomas Maeder; Peter Ryser

2009-01-01

366

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

367

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

368

Black Branes as Piezoelectrics  

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

369

Black branes as piezoelectrics.  

PubMed

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

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

2012-12-14

370

Effects of Cu, Zn on the Wettability and Shear Mechanical Properties of Sn-Bi-Based Lead-Free Solders  

NASA Astrophysics Data System (ADS)

Effects of minor Cu, Zn additions on the wettability, microstructures, and shear properties of Sn-Bi-based lead-free solder joints were investigated. The results show that a Cu addition promotes the wetting ratio of solder alloy, while Zn creates the opposite effect. The Cu5Zn8 intermetallic compound layer at the interface of Sn-40Bi-2Zn-0.1Cu and the Cu substrate alters the surface tension, which increases the contact angle. Also, this type of intermetallic compound contributes to the change of three wetting indicators. A proper amount of Cu, Zn increased the wetting force and decreased the wetting time, while the variation in the trend of withdrawing force is consistent with that of contact angle. From joint shear test results, the shear force decreased in the following order: Sn-40Bi-0.1Cu, Sn-58Bi, and Sn-40Bi-2Zn-0.1Cu solder joints. Cu additions refined the grain size of the Bi-rich phase and decreased the interface brittleness, which is the reason for the improvement of the shear strength of Sn-40Bi-0.1Cu solder joints. In contrast, Zn weakened the shear strength due to the brittle nature of the Zn-rich phase and the chemical activity of Zn.

Shen, Jun; Pu, Yayun; Yin, Henggang; Tang, Qin

2014-11-01

371

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

SciTech Connect

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

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

1996-03-01

372

Multimaterial piezoelectric fibres  

NASA Astrophysics Data System (ADS)

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?m 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.

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

373

Present Status of Polymer: Ceramic Composites for Pyroelectric Infrared Detectors  

Microsoft Academic Search

Ferroelectrics:Polymer composites can be considered an established substitute to conventional electro-ceramics and to ferroelectric polymers. The composites have unique blend of polymeric properties such as mechanical flexibility, high strength, formability, and low cost with high electro-active properties of ceramic materials. It has attracted considerable interest because of their potential use in pyroelectric infrared detecting devices and piezoelectric transducers. These flexible

A. K. Batra; M. D. Aggarwal; Matthew E. Edwards; Amar Bhalla

2008-01-01

374

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

NASA Technical Reports Server (NTRS)

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

Plante, Jeannete

2010-01-01

375

The piezoelectric response of nanotwinned BaTiO3.  

PubMed

The piezoelectric properties of tetragonal BaTiO(3) crystals with a very high density of 90 degrees twin domain boundaries are analyzed in the framework of the Ginzburg-Landau-Devonshire theory. Computer simulations predict a considerable enhancement of piezoelectric coefficients for domain thicknesses below 50 nm. This enhancement is much larger than the effect of the domain wall broadening mechanism of Rao and Wang (2007 Appl. Phys. Lett. 90 041915), but it is still a too weak effect to explain the domain density enhancement observed in the experiments of Wada and Tsurumi (2004 Br. Ceram. Trans. 103 93). The phenomenon observed here should nevertheless manifest in materials with nanoscopic domains, such as relaxor ferroelectrics and artificial ferroelectric nanostructures. PMID:19417537

Hlinka, J; Ondrejkovic, P; Marton, P

2009-03-11

376

Characterization of Recrystallization and Microstructure Evolution in Lead-Free Solder Joints Using EBSD and 3D-XRD  

NASA Astrophysics Data System (ADS)

Development of vulnerable high-angle grain boundaries (and cracks) from low-angle boundaries during thermal cycling by means of continuous recrystallization was examined in fine-pitch ball grid array (BGA) packages with Sn-3.0Ag-0.5Cu (wt.%) (SAC305) lead-free solder joints. Electron backscatter diffraction (EBSD) and differential-aperture x-ray microscopy (DAXM or 3D-XRD) were used for surface and subsurface characterization. A large number of subgrain boundaries were observed in the parent orientation using both techniques. However, unlike studies of anisotropic deformation in noncubic metals at much lower homologous temperatures, no streaked diffraction peaks were observed in DAXM Laue patterns within each 1 ?m3 voxel after thermal cycling, suggesting that geometrically necessary dislocations (GNDs) are effectively absorbed by the preexisting subgrain boundaries. Storage at room temperature (0.6 T m) prior to DAXM measurement may also facilitate recovery processes to reduce local GND contents. Heterogeneous residual elastic strains were found near the interface between a precipitated Cu6Sn5 particle and the Sn grain, as well as near particular subgrain boundaries in the parent orientation. Grain boundary migration associated with recrystallization resulted in regions without internal strains, subgrain boundaries, or orientation gradients. Development of new grain orientations by continuous recrystallization and subsequent primary recrystallization and grain growth occurred in the regions where the cracks developed. Orientation gradients and subgrain structure were observed within newly formed recrystallized grains that could be correlated with slip systems having high Schmid factors.

Zhou, Bite; Bieler, Thomas R.; Lee, Tae-Kyu; Liu, Wenjun

2013-02-01

377

Polarity effect of electromigration on intermetallic compound (IMC) formation in lead-free solder V-groove samples  

NASA Astrophysics Data System (ADS)

With the trend of further miniaturization of very-large-scale-integration (VLSI) of circuits, electromigration becomes a reliability concern in solder alloys. The polarity effect of electromigration on intermetallic compound (IMC) formation at the anode and the cathode in solder V-groove samples has been investigated. The V-groove solder line samples, with width of about 100 mum and length of 500--700 mum, were used to study the change in thickness and morphology of interfacial IMC at anode and cathode in the SnAg 3.8Cu0.7/Cu system under different current density and temperature settings. The current densities were in the range of 103 to 104A/ cm2 and the temperature settings were 120 C, 150C and 180C. The samples were formed by flowing molten lead-free solder SnAg 3.8Cu0.7 into V-grooves etched on (001) silicon wafers, and two copper wires were used as electrodes. We observed that IMC transformed from initial scallop-type into layer-type morphology with or without applying current. Due to the polarity of electric current and the local current crowding, IMC transformed from scallop-type into layer-type morphology differently from cathode to anode. We also found that the same IMCs of Cu6Sn 5 and Cu3Sn formed at solder/Cu interfaces with or without the passage of electric current. The growth of IMC has been enhanced by electric current at the anode and inhibited at the cathode, comparing with samples without applying current. A kinetic theory is derived, based on the Cu mass flux transport in the sample, to model the growth rate of IMC at anode and cathode.

Gan, Hua

378

Superplastic ceramics  

SciTech Connect

Despite the extensive studies of superplastic behavior in metallic systems, only very limited work has been performed on ceramics or ceramic composites. The demonstration of true superplastic behavior in ceramics is of very recent origin. The ceramic-base materials made superplastic to date are based on the principles developed for metallic alloys and claims of observations of both types of superplasticity have been made for ceramic materials. The purpose of this paper is to summarize recent work on superplastic behavior in ceramics and ceramic composites and comment on related work in intermetallics, geological materials, and nanophase materials. So far, only limited work has demonstrated superplastic behavior in tension in fine-grained, fully polycrystalline ceramics. It is noted that the grain sizes required for fine grain superplasticity are about 10 {mu}m or less for metals, but about 1 {mu}m or less for ceramics. Three fine-grained polycrystalline ceramics in which superplasticity has been demonstrated in tension are 3 mol% yttria-stabilized tetragonal zirconia polycrystal (Y-TZP), Y-TZP containing 20 wt% Al{sub 2}O{sub 3} particles (Al{sub 2}O{sub 3}/YTZ), and Al{sub 2}O{sub 3}.

Nieh, T.G.; Wadsworth, J. (Lockheed Missles and Space Co., Inc., Palo Alto, CA (US))

1990-01-01

379

PIEZOELECTRIC POWER SCAVENGING OF MECHANICAL VIBRATION ENERGY  

E-print Network

PIEZOELECTRIC POWER SCAVENGING OF MECHANICAL VIBRATION ENERGY PIEZOELECTRIC POWER SCAVENGING and magneticand magnetic field.field. Piezoelectric Materials as Smart Material- Among the all smart materials, piezoelectric materials are of great interest, as they are commonly used as sensors, actuators and memory

Ervin, Elizabeth K.

380

Using Piezoelectric Materials for Wearable Electronic Textiles  

E-print Network

Using Piezoelectric Materials for Wearable Electronic Textiles Joshua Edmison, Mark Jones, Zahi Oct. 8, 2002 Tom Martin, ISWC 2 Overview · Introduction · Piezoelectric materials · Glove prototype Piezoelectric materials · Piezoelectric film (PVDF) · Produce voltage based upon applied force (10mV ­ 100V

381

Effect of the Cu thickness on the stability of a Ni\\/Cu bilayer UBM of lead free microbumps during liquid and solid state aging  

Microsoft Academic Search

The present study focuses on liquid and solid phase reactions between an electrodeposited bilayer UBM and Sn, which is chosen as worst case solder material for lead free bumping. Small sized bumps were realized by electrodeposition using one lithographic mask for electrodepositing the UBM and the solder. The bilayer UBM consists of an electrodeposited Ni and Cu layer (Nied, Cued)

C. Jurenka; Jon Yeon Kim; M. J. Wolf; G. Engelmann; O. Ehrmann; Jin Yu; H. Reichl

2005-01-01

382

Ceramic Processing  

SciTech Connect

Ceramics represent a unique class of materials that are distinguished from common metals and plastics by their: (1) high hardness, stiffness, and good wear properties (i.e., abrasion resistance); (2) ability to withstand high temperatures (i.e., refractoriness); (3) chemical durability; and (4) electrical properties that allow them to be electrical insulators, semiconductors, or ionic conductors. Ceramics can be broken down into two general categories, traditional and advanced ceramics. Traditional ceramics include common household products such as clay pots, tiles, pipe, and bricks, porcelain china, sinks, and electrical insulators, and thermally insulating refractory bricks for ovens and fireplaces. Advanced ceramics, also referred to as ''high-tech'' ceramics, include products such as spark plug bodies, piston rings, catalyst supports, and water pump seals for automobiles, thermally insulating tiles for the space shuttle, sodium vapor lamp tubes in streetlights, and the capacitors, resistors, transducers, and varistors in the solid-state electronics we use daily. The major differences between traditional and advanced ceramics are in the processing tolerances and cost. Traditional ceramics are manufactured with inexpensive raw materials, are relatively tolerant of minor process deviations, and are relatively inexpensive. Advanced ceramics are typically made with more refined raw materials and processing to optimize a given property or combination of properties (e.g., mechanical, electrical, dielectric, optical, thermal, physical, and/or magnetic) for a given application. Advanced ceramics generally have improved performance and reliability over traditional ceramics, but are typically more expensive. Additionally, advanced ceramics are typically more sensitive to the chemical and physical defects present in the starting raw materials, or those that are introduced during manufacturing.

EWSUK,KEVIN G.

1999-11-24

383

Ceramics Monthly  

NSDL National Science Digital Library

If you've ever thrown some clay around or experimented with different glazes (and even if you haven't), you'll want to turn the electronic pages of Ceramics Monthly. Published ten times a year, the magazine focuses on all things ceramics, and visitors to their site can read selected articles about exhibitions, installations, ceramics techniques, and those ceramicists who are making their mark in the field. Those already in the ceramics field will also want to make note of the "Call for Entries" area of the site.

384

Design and fabrication of lanthanum-doped tin-silver-copper lead-free solder for the next generation of microelectronics applications in severe environment  

NASA Astrophysics Data System (ADS)

Tin-Lead solder (Sn-Pb) has long been used in the Electronics industry. But, due to its toxic nature and environmental effects, certain restrictions are made on its use by the European Rehabilitation of Hazardous Substances (RoHS) directive, and therefore, many researchers are looking to replace it. The urgent need for removing lead from solder alloys led to the very fast introduction of lead-free solder alloys without a deep knowledge of their behavior. Therefore, an extensive knowledge and understanding of the mechanical behavior of the emerging generation of lead-free solders is required to satisfy the demands of structural reliability. Sn-Ag-Cu (SAC) solders are widely used as lead-free replacements but their coarse microstructure and formation of hard and brittle Inter-Metallic Compounds (IMCs) have limited their use in high temperature applications. Many additives are studied to refine the microstructure and improve the mechanical properties of SAC solders including iron (Fe), bismuth (Bi), antimony (Sb) and indium (In) etc. Whereas many researchers studied the impact of novel rare earth (RE) elements like lanthanum (La), cerium (Ce) and lutetium (Lu) on SAC solders. These RE elements are known as vitamins of metals because of their special surface active properties. They reduce the surface free energy, refine the grain size and improve the mechanical properties of many lead free solder alloys like Sn-Ag, Sn-Cu and SAC but still a systematic study is required to explore the special effects of La on the eutectic SAC alloys. The objective of this PhD thesis is to extend the current knowledge about lead free solders of SAC alloys towards lanthanum doping with varying environmental conditions implemented during service. This thesis is divided into six main parts.

Sadiq, Muhammad

385

Electrical admittance of piezoelectric parallelepipeds: application to tensorial characterization of piezoceramics  

NASA Astrophysics Data System (ADS)

This work deals with the characterization of functional properties, including determination of mechanical and electrical losses, of piezoelectric materials using only one sample and one measurement. First, the natural resonant frequencies of a piezoelectric parallelepiped are calculated and the electrical admittance is determined from calculations of the charge quantity on both electrodes of the parallelepiped. A first validation of the model is performed using a comparison with Mason's model. Results are reported for a PMN-34.5PT ceramic cube and a good agreement is found between experimental admittance measurements and their modeling. The functional properties of the PMN-34.5PT are then extracted.

Diallo, O.; Clezio, E. Le; Delaunay, T.; Bavencoffe, M.; Feuillard, G.

2014-01-01

386

Determination of the reduced matrix of the piezoelectric, dielectric, and elastic material constants for a piezoelectric material with C? symmetry.  

PubMed

We present a procedure for determining the reduced piezoelectric, dielectric, and elastic coefficients for a C(?) material, including losses, from a single disk sample. Measurements have been made on a Navy III lead zirconate titanate (PZT) ceramic sample and the reduced matrix of coefficients for this material is presented. In addition, we present the transform equations, in reduced matrix form, to other consistent material constant sets. We discuss the propagation of errors in going from one material data set to another and look at the limitations inherent in direct calculations of other useful coefficients from the data. PMID:21937302

Sherrit, Stewart; Masys, Tony J; Wiederick, Harvey D; Mukherjee, Binu K

2011-09-01

387

Piezoelectric motor development at AlliedSignal Inc., Kansas City Division  

SciTech Connect

The Kansas City Division of AlliedSignal Inc. has been investigating the fabrication and use of piezoelectric motors in mechanisms for United States Department of Energy (DOE) weapons applications for about four years. These motors exhibit advantages over solenoids and other electromagnetic actuators. Prototype processes have been developed for complete fabrication of motors from stock materials, including abrasive machining of piezoelectric ceramics and more traditional machining of other motor components, electrode plating and sputtering, electric poling, cleaning, bonding and assembly. Drive circuits have been fabricated and motor controls are being developed. Laboratory facilities have been established for electrical/mechanical testing and evaluation of piezo materials and completed motors. Recent project efforts have focused on the potential of piezoelectric devices for commercial and industrial use. A broad range of various motor types and application areas has been identified, primarily in Japan. The Japanese have been developing piezo motors for many years and have more recently begun commercialization. Piezoelectric motor and actuator technology is emerging in the United States and quickly gaining in commercial interest. The Kansas City Division is continuing development of piezoelectric motors and actuators for defense applications while supporting and participating in the commercialization of piezoelectric devices with private industry through various technology transfer and cooperative development initiatives.

Pressly, R.B.; Mentesana, C.P.

1994-11-01

388

Micromechanics of piezoelectric composites with improved effective piezoelectric constant  

Microsoft Academic Search

This paper is concerned with the derivation of a micromechanics model of a new type of piezoelectric fiber reinforced composite\\u000a (PFRC) materials. A continuum mechanics approach is employed to determine the effective properties of these composites. The\\u000a piezoelectric fibers of these composites are considered to be electroded at the fibermatrix interface such that the electric\\u000a fields in the fiber and

Manas Chandra Ray

2006-01-01

389

Improved current and charge amplifiers for driving piezoelectric loads  

E-print Network

Improved current and charge amplifiers for driving piezoelectric loads Andrew J. Fleming and S. O, Callaghan 2308, Australia. ABSTRACT Piezoelectric transducers are known to exhibit less hysterisis when, Piezoelectric, Capacitive, Load, Amplifier, Zero Offset, Compliance, Feedback 1. INTRODUCTION Piezoelectric

Fleming, Andrew J.

390

Piezoactuator Design Considering the Optimum Placement of FGM Piezoelectric Material  

E-print Network

Piezoactuator Design Considering the Optimum Placement of FGM Piezoelectric Material Ronny C has been explored in piezoelectric materials to improve properties and to increase the lifetime of piezoelectric actuators. Elastic, piezoelectric, and dielectric properties are graded along the thickness

Paulino, Glaucio H.

391

Stabilization of a piezoelectric system  

E-print Network

We consider a stabilization problem for a piezoelectric system. We prove an exponential stability result under some Lions geometric condition. Our method is based on an identity with multipliers that allows to show an appropriate observability estimate.

Ammari, K

2010-01-01

392

Modeling of Piezoelectric Tube Actuators  

E-print Network

A new dynamic model is presented for piezoelectric tube actuators commonly used in high-precision instruments. The model captures coupling between motions in all three axes such as bending motion due to a supposedly pure ...

El Rifai, Osamah M.

393

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

394

Piezoelectric Rotary Tube Motor  

NASA Technical Reports Server (NTRS)

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

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

2011-01-01

395

Densification, crystallization, and electrical properties of lead zirconate titanate glass-ceramics  

Microsoft Academic Search

Piezoelectric glass-ceramics in the lead zirconate titanato-lead silicate system were developed. SiO2 was required for glass formability, and excess PbO allowed low temperature processing. The amounts of those constituents were limited by the optimization of the piezoelectric properties. Only a small region of compositions in this system yielded the desired combination of glass formability, crystallization and densification behavior, and resulting

Boen Houng; Chan Young Kim; Michael J. Haun

2000-01-01

396

On the relative contribution of temperature, moisture and vapor pressure to delamination in a plastic IC package during lead-free solder reflow  

Microsoft Academic Search

The elimination of lead in electronics assembly has presented challenges on the process. During the conventional eutectic tin-lead solder reflow process, the delamination of the interface between the leadframe pad and the encapsulant has been found to be a precursor to the popcorning of plastic IC packages. The melting point of lead-free solder is more than 30-40C higher than that

Hu Guojun; Andrew A. O. Tay

2005-01-01

397

The liquid structure of Sn-based lead-free solders and the correlative effect in liquid-solid interfacial reaction  

Microsoft Academic Search

Two lead-free solder alloys, Sn-0.7Cu and Sn-2Cu (wt.%), have been examined using X-ray diffraction method. The liquid structure of Sn-0.7Cu is similar to that of pure Sn. A pre-peak has been found in the low Q part on the structure factor S(Q) for Sn-2Cu tested under 260C, but it disappeared finally when the testing temperature reached 400C. The interfacial reactions

Ning Zhao; Xuemin Pan; Haitao Ma; Chuang Dong; Shuhong Guo; Wen Lu; Lai Wang

2008-01-01

398

Superior piezoelectric composite films: taking advantage of carbon nanomaterials.  

PubMed

Piezoelectric composites comprising an active phase of ferroelectric ceramic and a polymer matrix have recently found numerous sensory applications. However, it remains a major challenge to further improve their electromechanical response for advanced applications such as precision control and monitoring systems. We here investigated the incorporation of graphene platelets (GnPs) and multi-walled carbon nanotubes (MWNTs), each with various weight fractions, into PZT (lead zirconate titanate)/epoxy composites to produce three-phase nanocomposites. The nanocomposite films show markedly improved piezoelectric coefficients and electromechanical responses (50%) besides an enhancement of ~200% in stiffness. The carbon nanomaterials strengthened the impact of electric field on the PZT particles by appropriately raising the electrical conductivity of the epoxy. GnPs have been proved to be far more promising in improving the poling behavior and dynamic response than MWNTs. The superior dynamic sensitivity of GnP-reinforced composite may be caused by the GnPs' high load transfer efficiency arising from their two-dimensional geometry and good compatibility with the matrix. The reduced acoustic impedance mismatch resulting from the improved thermal conductance may also contribute to the higher sensitivity of GnP-reinforced composite. This research pointed out the potential of employing GnPs to develop highly sensitive piezoelectric composites for sensing applications. PMID:24398819

Saber, Nasser; Araby, Sherif; Meng, Qingshi; Hsu, Hung-Yao; Yan, Cheng; Azari, Sara; Lee, Sang-Heon; Xu, Yanan; Ma, Jun; Yu, Sirong

2014-01-31

399

Superior piezoelectric composite films: taking advantage of carbon nanomaterials  

NASA Astrophysics Data System (ADS)

Piezoelectric composites comprising an active phase of ferroelectric ceramic and a polymer matrix have recently found numerous sensory applications. However, it remains a major challenge to further improve their electromechanical response for advanced applications such as precision control and monitoring systems. We here investigated the incorporation of graphene platelets (GnPs) and multi-walled carbon nanotubes (MWNTs), each with various weight fractions, into PZT (lead zirconate titanate)/epoxy composites to produce three-phase nanocomposites. The nanocomposite films show markedly improved piezoelectric coefficients and electromechanical responses (50%) besides an enhancement of ?200% in stiffness. The carbon nanomaterials strengthened the impact of electric field on the PZT particles by appropriately raising the electrical conductivity of the epoxy. GnPs have been proved to be far more promising in improving the poling behavior and dynamic response than MWNTs. The superior dynamic sensitivity of GnP-reinforced composite may be caused by the GnPs high load transfer efficiency arising from their two-dimensional geometry and good compatibility with the matrix. The reduced acoustic impedance mismatch resulting from the improved thermal conductance may also contribute to the higher sensitivity of GnP-reinforced composite. This research pointed out the potential of employing GnPs to develop highly sensitive piezoelectric composites for sensing applications.

Saber, Nasser; Araby, Sherif; Meng, Qingshi; Hsu, Hung-Yao; Yan, Cheng; Azari, Sara; Lee, Sang-Heon; Xu, Yanan; Ma, Jun; Yu, Sirong

2014-01-01

400

Equivalent circuit and optimum design of a multilayer laminated piezoelectric transformer.  

PubMed

A multilayer laminated piezoelectric Pb(Zr(1-x)Ti(x))O(3) (PZT) ceramic transformer, operating in a half- wavelength longitudinal resonant mode (?/2 mode), has been analyzed. This piezoelectric transformer is composed of one thickness-polarized section (T-section) for exciting the longitudinal mechanical vibrations, two longitudinally polarized sections (L-section) for generating high-voltage output, and two insulating layers laminated between the T-section and L-section layers to provide insulation between the input and output sections. Based on the piezoelectric constitutive and motion equations, an electro-elasto-electric (EEE) equivalent circuit has been developed, and correspondingly, an effective EEE coupling coefficient was proposed for optimum design of this multilayer transformer. Commercial finite element analysis software is used to determine the validity of the developed equivalent circuit. Finally, a prototype sample was manufactured and experimental data was collected to verify the model's validity. PMID:23443686

Dong, Shuxiang; Carazo, Alfredo Vazquez; Park, Seung Ho

2011-12-01

401

Physics of failure modes in accelerometers utilizing single crystal piezoelectric materials  

NASA Astrophysics Data System (ADS)

For over forty years, the lead zirconate -- lead titanate system (PZT) has been the industrial standard of sensing materials for piezoelectric accelerometers. This ceramic has established a reliability benchmark given the uniformity of its electromechanical properties, the negligible dependence of these properties on temperature and pre-stress, and the ability to manufacture the sensing element cost-effectively into a myriad of geometries. Today, revolutionary advances in the growth of single crystal piezoelectric materials have spawned the evolution of novel sensor designs. With piezoelectric coefficients exceeding 2000 pC/N, and electromechanical coupling factors above 90%, single crystals of Pb(Mg1/3Nb2/3)O3-PbTiO3 [PMNT] and Pb(Zn1/3Nb2/3)O3-PbTiO3 [PZNT] have the potential of superseding PZT ceramics in certain critical applications. This dissertation reports the first results of the design, development and performance characterization for an accelerometer utilizing bulk, single crystal piezoelectric materials. Numerous prototypes, developed in the compression and flexural-mode design configurations, exhibit charge sensitivities that exceed that of their PZT-counterparts by a factor of greater than three times. The introduction of accelerometer prototypes employing single crystal piezoelectric material is an important advancement for the sensor industry. Root-cause failure processes were identified and subsequently used as a reliability enhancement tool to prevent device failures through robust design and manufacturing practices. Crystal machining techniques were analyzed in which a scanning electron microscope was used to inspect the crystal surface for defects. Inhomogeneity in the piezoelectric properties over the surface of the crystal was quantified and recognized as a major obstacle to commercialization. Measurements were made on the material's fracture toughness and electromechanical properties over a wide temperature range. Effects of aging and mechanical cycling were also studied. The identification of these failure modes was the basis from which to develop optimal design guidelines specific to the single crystal piezoelectric material. Integral to this analysis was assessing the reliability of single crystal piezoelectric materials vis-a-vis ceramic PZT. The knowledge garnered from this research now serves as the cornerstone from which to develop a new-generation vibration sensor.

Wlodkowski, Paul Alexander

1999-11-01

402

Effect of dielectrophoretic structuring on piezoelectric and pyroelectric properties of lead titanate-epoxy composites  

NASA Astrophysics Data System (ADS)

Functional granular composites of lead titanate particles in an epoxy matrix prepared by dielectrophoresis show enhanced dielectric, piezoelectric and pyroelectric properties compared to 0–3 composites for different ceramic volume content from 10% to 50%. Two structuring parameters, the interparticle distance and the percentage of 1–3 connectivity are used based on the Bowen model and the mixed connectivity model respectively. The degree of structuring calculated according to both models correlate well with the increase in piezoelectric and pyroelectric sensitivities of the composites. Higher sensitivity of the electroactive properties are observed at higher ceramic volume fractions. The effect of electrical conductivity of the matrix on the pyroelectric responsivity of the composites has been demonstrated to be a key parameter in governing the pyroelectric properties of the composites.

Khanbareh, H.; van der Zwaag, S.; Groen, W. A.

2014-10-01

403

Processing ceramics  

NASA Technical Reports Server (NTRS)

A method of hot hydrostatic pressing of ceramics is described. A detailed description of the invention is given. The invention is explained through an example, and a figure illustrates the temperature and pressure during the hot hydrostatic pressing treatment.

Moritoki, M.; Fujikawa, T.; Miyanaga, J.

1984-01-01

404

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

405

Relation of the external mechanical stress to the properties of piezoelectric materials for energy harvesting  

NASA Astrophysics Data System (ADS)

We investigated the piezoelectric properties and the generation of voltage and power under the mechanical compressive loads for three types of piezoelectric ceramics 0.2Pb(Mg1/3Nb2/3)O3-0.8Pb(Zr0.475Ti0.525)O3 (soft-PZT), 0.1Pb(Mg1/3Sb2/3)O3- 0.9Pb(Zr0.475Ti0.525)O3 (hard-PZT) and [0.675Pb(Mg1/3Nb2/3)O3-0.35PbTiO3]+5 wt% BaTiO3 (textured-PMNT). The piezoelectric d 33 coefficients of all specimens increased with increasing compressive load. The generated voltage and power showed a linear relation and square relation to the applied stress, respectively. These results were larger than those calculated using the simple piezoelectric equation due to the non-linear characteristics of the ceramics, so they were evaluated with a simple model based on a non-linear relation.

Jeong, Soon-Jong; Kim, Min-Soo; Lee, Dae-Su; Song, Jae-Sung; Cho, Kyung-Ho

2013-12-01

406

PMN-PT piezoelectric-electrostrictive bi-layer composite actuators  

NASA Astrophysics Data System (ADS)

In the past few decades, significant advances have been achieved to replace the conventional actuators, including hydraulic, shape memory alloy, electromagnetic and linear induction, with piezoelectric actuators since they are light weight and small in size, have precision positioning capabilities, offer a wide range of generative force, consume less power, and provide higher durability and reliability. The strain produced by bulk polycrystalline piezoelectric ceramics and single crystals are typically in the range of 0.1 to 1%, respectively, which is still low for many applications. Therefore, various strain amplification designs including multilayer, bimorph, unimorph, flextensional actuators (Moonie and cymbal), co-fired and functionally graded ceramics have been proposed to enhance the displacement. In this investigation, Piezoelectric/Electrostrictive Bi-Layer Monolithic Composites (PE-MBLC) were fabricated by co-pressing and co-sintering of the piezoelectric (PMN-PT 65/35: P) and electrostrictive (PMN/PT 90/10: E) powders. Flat and dome shaped of PE-MBLCs were obtained by optimizing processing conditions such as pressing pressure and sintering temperature. In addition, poling conditions of bilayer composite actuators were thoroughly studied to maximize their electromechanical properties. It was found that composites had lower d33eff and Keff values than the calculated values. This was attributed to a significant difference between relative permittivities of P and E materials as well as the presence of induced stresses in both P and E layers after sintering that hindered domain switching within piezoelectric layer during poling. The shape change (planar to dome), electromechanical properties, and actuation performance of PE-MBLC actuators were examined as a function of volume percent of piezoelectric phase. The highest displacement 15 mum was obtained from PE-MBLC actuator with 50 volume % piezoelectric phase due to the transverse strain response of piezoelectric and electrostrictive layers, the geometry of the composites, and the domain reorientation. Two designs of the flextensional actuators were also fabricated. In the first design, two truncated thin metal caps were attached to a flat PE-MBLC. In the second design, dome-shaped PE-MBLC actuators with various volume fraction of piezoelectric phase were attached to a flat metallic plate. The actuation evaluation showed that 21 to 70 mum displacement could be achieved by such designs.

Ngernchuklin, Piyalak

407

Coupled Simulation of Circuit and Piezoelectric Laminates  

E-print Network

In this paper, an algorithm for the coupled simulation of circuit and piezoelectric laminate devices is presented. A finite element solver for piezoelectric laminates is included in the SPICE framework as a capacitor. The charge of this capacitor is a function of both the terminal voltage and the mechanical strain in the piezoelectric material. The coupled simulator allows simulation of novel micropower generation circuits based on piezoelectric laminates. 1.

unknown authors

408

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

409

Wideband piezoelectric pressure transducer  

NASA Astrophysics Data System (ADS)

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

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

1986-02-01

410

Piezoelectric Water Drop Energy Harvesting  

NASA Astrophysics Data System (ADS)

Piezoelectric materials convert mechanical deformation directly into electrical charges, which can be harvested and used to drive micropower electronic devices. The low power consumption of such systems on the scale of microwatts leads to the possibility of using harvested vibrational energy due to its almost universal nature. Vibrational energy harvested using piezoelectric cantilevers provides sufficient output for small-scale power applications. This work reports on vibrational energy harvesting from free-falling droplets at the tip of lead zirconate titanate piezoelectric-based cantilevers. The harvester incorporates a multimorph clamped-free cantilever made of lead zirconate titanate piezoelectric thick films. During the impact, the droplet's kinetic energy is transferred to the form of mechanical stress, forcing the piezoelectric structure to vibrate and thereby producing charges. Experimental results show an instantaneous drop-power of 2.15 mW cm-3 g-1. The scenario of a medium intensity of falling water drops, i.e., 200 drops per second, yielded a power of 0.48 W cm-3 g-1 per second.

Al Ahmad, Mahmoud

2014-02-01

411

Piezoelectric Bimorph Optical-Fiber Sensor  

Microsoft Academic Search

We propose and demonstrate a novel high-voltage optical-fiber sensor. This sensor consists of an emitting fiber, a receiving fiber, and a piezoelectric bimorph transducer. The emitting fiber is fixed in a base, whereas the receiving fiber is mounted on the free end of the piezoelectric bimorph transducer. When a voltage is applied to the piezoelectric bimorph transducer, its free end

Fengguo Sun; Gaozhi Xiao; Zhiyi Zhang; Chander P. Grover

2004-01-01

412

Recent developments of polar piezoelectric polymers  

Microsoft Academic Search

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

Eiichi Fukada

2006-01-01

413

POWER HARVESTING PIEZOELECTRIC SHUNT DAMPING 1  

E-print Network

POWER HARVESTING PIEZOELECTRIC SHUNT DAMPING 1 A. J. Fleming ¤ S. O. R. Moheimani ¤ ¤ School piezoelectric transducer. Typical shunt networks require inductance values of up to thousands of Henries introduces an e±cient, light weight, and small-in-size technique for implementing piezoelectric shunt damping

Fleming, Andrew J.

414

Piezoelectric and mechanical properties of fatigue resistant, self-healing PZT-ionomer composites  

NASA Astrophysics Data System (ADS)

Piezoelectric ceramic-polymer composites with 0-3 connectivity were fabricated using lead zirconium titanate (PZT) powder dispersed in an ionomer (Zn ionomer) and its reference ethylene methacrylic acid copolymer (EMAA) polymer matrix. The PZT-Zn ionomer and PZT-EMAA composites were prepared by melt extrusion followed by hot pressing. The effects of poling conditions such as temperature, time and electric field on the piezoelectric properties of the composites were investigated. The experimentally observed piezoelectric charge coefficient and dielectric constant of the composites were compared with theoretical models. The results show that PZT-Zn ionomer composites have better piezoelectric properties compared to PZT-EMAA composites. The static and fatigue properties of the composites were investigated. The PZT-Zn ionomer composites were found to have excellent fatigue resistance even at strain levels of 4%. Due to the self-healing capabilities of the ionomer matrix, the loss of piezoelectric properties after high strain tensile cyclic loading could be partially recovered by thermal healing.

James, N. K.; Lafont, U.; van der Zwaag, S.; Groen, W. A.

2014-05-01

415

Ceramic keratoprostheses.  

PubMed

This paper describes a new type of corneal prosthesis made of aluminum oxide ceramic. The implant consists of a retaining plate with a 3-mm central performation to which an optical cylinder is threaded. The cylinder also made of ceramic material, has a high refractive index and 60 diopters of power. Experimental study has shown that soft tissue adheres to the surface of the material, thus preventing its extrusion and surface epithelial ingrowth. The techniques of implantation and the early results in seven patients are described. PMID:7402597

Polack, F M; Heimke, G

1980-07-01

416

Ceramics Analysis  

NASA Technical Reports Server (NTRS)

Lewis Research Center developed the CARES/LIFE software, which predicts the performance of brittle structures over time, such as ceramic compounds. Over 300 companies have used a version of the code, including Philips Display Components Company, AlliedSignal, Solar Turbines Incorporated, and TRW, Inc. for everything from engines to television tubes. The software enables a designer to test a variety of configurations for probability of failure and to adjust the structure's geometry to minimize the predicted failure or maximize durability for the lifetime of the ceramic component.

1996-01-01

417

Elastic properties of spherically anisotropic piezoelectric composites  

NASA Astrophysics Data System (ADS)

Effective elastic properties of spherically anisotropic piezoelectric composites, whose spherically anisotropic piezoelectric inclusions are embedded in an infinite non-piezoelectric matrix, are theoretically investigated. Analytical solutions for the elastic displacements and the electric potentials under a uniform external strain are derived exactly. Taking into account of the coupling effects of elasticity, permittivity and piezoelectricity, the formula is derived for estimating the effective elastic properties based on the average field theory in the dilute limit. An elastic response mechanism is revealed, in which the effective elastic properties increase as inclusion piezoelectric properties increase and inclusion dielectric properties decrease. Moreover, a piezoelectric response mechanism, of which the effective piezoelectric response vanishes due to the symmetry of spherically anisotropic composite, is also disclosed.

Wei, En-Bo; Gu, Guo-Qing; Poon, Ying-Ming

2010-09-01

418

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

419

Piezoelectric Scanners Piezoelectric materials are ceramics that change dimensions in response  

E-print Network

corresponds to the electronic density of states at the surface. STMs actually sense the number of filled irregular surfaces with high precision, but the measurement takes more time. � As a first approximation or unfilled electron states near the Fermi surface, within an energy range

Moeck, Peter

420

Assessment of the effects of the Japanese shift to lead-free solders and its impact on material substitution and environmental emissions by a dynamic material flow analysis.  

PubMed

Lead-free electronics has been extensively studied, whereas their adoption by society and their impact on material substitution and environmental emissions are not well understood. Through a material flow analysis (MFA), this paper explores the life cycle flows for solder-containing metals in Japan, which leads the world in the shift to lead-free solders in electronics. The results indicate that the shift has been progressing rapidly for a decade, and that substitutes for lead in solders, which include silver and copper, are still in the early life cycle stages. The results also show, however, that such substitution slows down during the late life cycle stages owing to long electronic product lifespans. This deceleration of material substitution in the solder life cycle may not only preclude a reduction in lead emissions to air but also accelerate an increase in silver emissions to air and water. As an effective measure against ongoing lead emissions, our scenario analysis suggests an aggressive recycling program for printed circuit boards that utilizes an existing recycling scheme. PMID:22964401

Fuse, Masaaki; Tsunemi, Kiyotaka

2012-11-01

421

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

422

V-stack piezoelectric actuator  

NASA Astrophysics Data System (ADS)

Aeroelastic control of wings by means of a distributed, trailing-edge control surface is of interest with regards to maneuvers, gust alleviation, and flutter suppression. The use of high energy density, piezoelectric materials as motors provides an appealing solution to this problem. A comparative analysis of the state of the art actuators is currently being conducted. A new piezoelectric actuator design is presented. This actuator meets the requirements for trailing edge flap actuation in both stroke and force. It is compact, simple, sturdy, and leverages stroke geometrically with minimum force penalties while displaying linearity over a wide range of stroke. The V-Stack Piezoelectric Actuator, consists of a base, a lever, two piezoelectric stacks, and a pre-tensioning element. The work is performed alternately by the two stacks, placed on both sides of the lever. Pre-tensioning can be readily applied using a torque wrench, obviating the need for elastic elements and this is for the benefit of the stiffness of the actuator. The characteristics of the actuator are easily modified by changing the base or the stacks. A prototype was constructed and tested experimentally to validate the theoretical model.

Ardelean, Emil V.; Clark, Robert L.

2001-07-01

423

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

424

Epitaxial piezoelectric MEMS on silicon  

NASA Astrophysics Data System (ADS)

This paper reports on the microfabrication and characterization of piezoelectric MEMS structures based on epitaxial Pb(Zr0.2Ti0.8)O3 (PZT) thin films grown on silicon wafers. Membranes and cantilevers are realized using a sequence of microfabrication processes optimized for epitaxial oxide layers. Different issues related to the choice of materials and to the influence of the fabrication processes on the properties of the piezoelectric films are addressed. These epitaxial PZT transducers can generate relatively large deflections at low bias voltages in the static mode. Estimations of the piezoelectric coefficient d31 of the epitaxial PZT thin film (100 nm) yield 130 pm V-1. In the dynamic mode, the performance of the epitaxial PZT transducers in terms of the resonant frequency, modal shape and quality factor are examined. An epitaxial PZT/Si cantilever (1000 2500 40 m3) resonating in air and in vacuum exhibits a deflection of several microns with quality factors of 169 and 284, respectively. For a 1500 m diameter membrane, the quality factor is 50 at atmospheric pressure, and this rises to 323 at a pressure of 0.1 mbar. These results indicate the high potential of epitaxial piezoelectric MEMS, which can impact a variety of technological applications.

Isarakorn, D.; Sambri, A.; Janphuang, P.; Briand, D.; Gariglio, S.; Triscone, J.-M.; Guy, F.; Reiner, J. W.; Ahn, C. H.; de Rooij, N. F.

2010-05-01

425

Design and Modelling a Mini-System with Piezoelectric Actuation  

E-print Network

1 Design and Modelling a Mini-System with Piezoelectric Actuation S. Noveanu1 , V.I. Csibi1 , A. I.ivan@femto-st.fr Abstract. In this paper a new mini-system with piezoelectric actuation is presented. The piezoelectric the input displacement, with facile connection with the piezoelectric actuator. The piezoelectric actuator

Paris-Sud XI, Université de

426

PPF Control of a Piezoelectric Tube Scanner (Invited Paper)  

E-print Network

PPF Control of a Piezoelectric Tube Scanner (Invited Paper) M. Ratnam, B. Bhikkaji, A. J. Fleming and S. O. R. Moheimani Abstract-- Piezoelectric tubes are commonly used in Scan- ning Tunnelling to a piezoelectric tube or placing the sample on the top of a piezoelectric tube, and actuating the piezoelectric

Fleming, Andrew J.

427

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

428

Development of fine scale PZT ceramic fiber\\/polymer shell composite transducers  

Microsoft Academic Search

The relic processing technique was used to fabricate fine-scale piezoelectric lead zirconate titanate (PZT) ceramic fiber\\/polymer shell composites. In this technique sacrificial activated carbon fabrics were soaked in a PZT precursor solution, dried, and heat treated to form piezoceramic relics. Relics were embedded with polymer, which was allowed to cure, and the resulting composites were polished, electroded, and poled. Different

Shai S. Livneh; Victor F. Janas; Ahmad Safari

1995-01-01

429

The Network Calculation of Elastic Constants of Piezoelectric Crystal of  

E-print Network

The Network Calculation of Elastic Constants of Piezoelectric Crystal of Different Orientations Applet Java Applet #12; III Abstract The elastic constants of piezoelectric crystal material are one of the most basic material properties. As most piezoelectric crystal materials are anisotropic

Wang, Ji

430

Piezoelectric Power Requirements for Active Vibration Control  

NASA Technical Reports Server (NTRS)

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

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

1997-01-01

431

Microstructure and Sn Crystal Orientation Evolution in Sn-3.5Ag Lead-Free Solders in High-Temperature Packaging Applications  

NASA Astrophysics Data System (ADS)

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 (2.5 mm 2.5 mm) Sn-3.5Ag solder joints between silicon dies and direct bonded copper substrates were thermally cycled between 5C and 200C. Sn crystal orientation and microstructure evolution during thermal cycling were characterized by electron backscatter diffraction in the scanning electron microscope. Comparisons were made between the observed initial texture and microstructure and its evolution during thermal cycling. Gradual lattice rotation and grain boundary misorientation evolution observed due to thermal cycling suggested a continuous recrystallization mechanism. Recrystallization behavior was correlated with dislocation slip activities.

Zhou, Bite; Muralidharan, Govindarajan; Kurumadalli, Kanth; Parish, Chad M.; Leslie, Scott; Bieler, Thomas R.

2014-01-01

432

The liquid structure of Sn-based lead-free solders and the correlative effect in liquid-solid interfacial reaction  

NASA Astrophysics Data System (ADS)

Two lead-free solder alloys, Sn-0.7Cu and Sn-2Cu (wt.%), have been examined using X-ray diffraction method. The liquid structure of Sn-0.7Cu is similar to that of pure Sn. A pre-peak has been found in the low Q part on the structure factor S(Q) for Sn-2Cu tested under 260C, but it disappeared finally when the testing temperature reached 400C. The interfacial reactions between liquid solders and Cu substrates at 260C were also studied. The results show that the IMC layer at Sn-2Cu/Cu joint is thicker than that at Sn-0.7Cu/Cu interface. The correlative effect of liquid structure on phase evolution in the solder joints are analyzed and discussed.

Zhao, Ning; Pan, Xuemin; Ma, Haitao; Dong, Chuang; Guo, Shuhong; Lu, Wen; Wang, Lai

2008-02-01

433

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

434

Design Envelopes and Optical Feature Extraction Techniques for Survivability of SnAg Lead-free Packaging Architectures Under Shock and Vibration  

Microsoft Academic Search

In this paper, a design-envelope approach based on optical feature extraction techniques has been investigated for drop and shock survivability of electronic packaging has been presented for 6-lead-free solder alloy systems. Solder alloy systems investigated include, Sn1Ag0.5Cu, Sn3Ag0.5Cu, Sn0.3Ag0.7Cu, Sn0.3Ag0.7Cu0.1Bi, Sn0.2Ag0.7Cu0.1Bi-0.1Ni, 96.5Sn 3.5Ag. Previously, digital image correlation (DIC) has been used for measurement of thermally induced deformation and material-characterization. In

Pradeep Lall; Deepti Iyengar; Sandeep Shantaram; Ranjit Pandher; Dhananjay Panchagade

2009-01-01

435

Interfacial Reactions of Sn, Sn-3.0Ag-0.5Cu, and Sn-9Zn Lead-Free Solders with Fe-42Ni Substrates  

NASA Astrophysics Data System (ADS)

Interfacial reactions between Sn, Sn-3.0 wt.%Ag-0.5 wt.%Cu (SAC), and Sn-9 wt.%Zn (SZ) lead-free solders and Fe-42 wt.%Ni (alloy 42) substrates at 240C, 255C, and 270C were investigated in this study. FeSn2, (Fe,Ni, Cu)Sn2, and (Ni,Fe)5Zn21 phases were formed, respectively, at the interface in the Sn/alloy 42, SAC/alloy 42, and SZ/alloy 42 couples. As the reaction time and temperature were increased, the layered intermetallic compound (IMC) assumed two distinct structures, i.e., a thicker layer and a pillar-shaped IMC, in all couples. The IMC thickness of these couples increased with the increase of reaction time and temperature. The IMC thickness was also proportional to the square root of the reaction time. The interfacial reaction mechanism of these couples was diffusion controlled.

Yen, Yee-Wen; Hsieh, Yu-Ping; Jao, Chien-Chung; Chiu, Chao-Wei; Li, Yi-Shan

2014-01-01

436

Microwave processing of ceramics  

SciTech Connect

This paper discusses the following topics on microwave processing of ceramics: Microwave-material interactions; anticipated advantage of microwave sintering; ceramic sintering; and ceramic joining. 24 refs., 4 figs. (LSP)

Katz, J.D.

1989-01-01

437

Characterization of micromachined piezoelectric PZT force sensors for dynamic scanning force microscopy  

NASA Astrophysics Data System (ADS)

The key component for the piezoelectric scanning force microscopy (SFM) is the piezoelectric force-sensing microcantilever. In this article, the resonance frequency and quality factor of Pb(Ti,Zr)O3 (PZT) microcantilevers; effective Young's modulus and piezoelectric Pb(Ti,Zr)O3 property of PZT layer of piezoelectric microcantilevers are discussed. The PZT microcantilevers after poling have quality factors such as 204 to 248 in air, and 608 to 1094 in vacuum. The calculated spring constants are in the range of 1.0-30.0 N/m for cantilevers with 0.64-1.7-?m-thick PZT layer and 125-300 ?m length. The force sensitivity and resolution of the PZT microcantilever are studied when it is oscillated by an external oscillator and applied to the cyclic contact SFM. Then the real transverse piezoelectric coefficient d31 of piezoelectric PZT thin films is derived from the measured sensitivity and effective Young's modulus. The derived effective Young's moduli of PZT layers slightly increases from 53.5 to 58 GPa as the thickness of the PZT layer increases. The d31 is around -35 pC/N which is about 8 times larger than the value of ZnO, and half the value of bulk PZT ceramics. The sensitivity of 0.98 fC/nm can be obtained by PZT force sensors. The longitudinal resolution obtained is 1.5 at a bandwidth of 125 Hz. Cantilevers with proper characteristics for different applications can be predicted, designed, and fabricated via the adjustment of the thickness ratio of each layer and the total thickness of the cantilever. Very clear images of an evaporated Au film on a smooth glass plate are obtained by an SFM with a PZT force sensor.

Lee, Chengkuo; Itoh, Toshihiro; Maeda, Ryutaro; Suga, Tadatomo

1997-05-01

438

High Performance Piezoelectric Thin Films for Shape Control in Large Inflatable Structures  

NASA Technical Reports Server (NTRS)

The objective of this research and development program was to develop PbZr(1-x)Ti(x)O3 (PZT) and Pb(1-x)Ba(x)Nb2O6 (PBN) materials with large piezoelectric response which are suitable for shape control in large inflatable structures. Two approaches were to be considered: (1) direct deposition of PZT and PBN films on flexible plastic or thin metal foil substrates, and (2) deposition on Si followed by fabrication of hybrid structures on mylar or kapton. Testing in shape control concepts was carried out at JPL and based on their results, the required modifications were made in the final film compositions and deposition techniques. The program objective was to identify and then optimize piezoelectric materials for NASA shape control applications. This involved the bulk piezoelectric and photovoltaic responses and the compatibility of the thin films with appropriate substrate structures. Within the PZT system, Rockwell has achieved the highest reported piezoelectric coefficient (d(sub 33) greater than 100 pC/N) of any ceramic composition. We used this experience in piezoelectric technology to establish compositions that can effectively address the issues of this program. The performance of piezoelectric thin films depends directly on d(sub ij) and Epsilon. The challenge was to find PZT compositions that maintained high d(sub ij) and Epsilon, while also exhibiting a large photovoltaic effect and integrate thin films of this composition into the system structure necessary to meet shape control applications. During the course of this program, several PZT and PLZT compositions were identified that meet these requirements. Two such compositions were successfully used in electrical and optical actuation studies of thin film structures.

Neurgaonkar, R. R.; Nelson, J. G.

1999-01-01

439