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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

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

4

KNN-NTK composite lead-free piezoelectric ceramic  

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

5

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

6

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

7

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

8

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.

9

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

10

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

11

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

12

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

13

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

14

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

15

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

16

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

17

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

18

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

19

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

20

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

21

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

22

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 0.04piezoelectric 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

23

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

PubMed

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

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

2014-02-01

24

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

25

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

26

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

27

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

28

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

29

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

30

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

31

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

32

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

33

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

34

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

35

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

36

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

37

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

38

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

39

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

40

ELECTROMECHANICAL, THERMAL PROPERTIES AND RADIATION HARDNESS TESTS OF PIEZOELECTRIC ACTUATORS AT LOW  

E-print Network

ELECTROMECHANICAL, THERMAL PROPERTIES AND RADIATION HARDNESS TESTS OF PIEZOELECTRIC ACTUATORS a dedicated facility located at CERI institute (Orléans, France) for radiation hardness tests of actuators a decrease of the maximum displacement X of the actuators tested from X ~40µm @ 300K down to 1.8µm-3.5 µm @ 1

Paris-Sud XI, Université de

41

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

42

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

43

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

44

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

45

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

46

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

47

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

48

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

49

EU contract number RII3-CT-2003-506395 CARE-Note-07-004-SRF Radiation hardness tests of piezoelectric actuators with fast neutrons at liquid helium  

E-print Network

EU contract number RII3-CT-2003-506395 CARE-Note-07-004-SRF SRF Radiation hardness tests was developed at IPN Orsay and used previously for radiation hardness test of calibrated cryogenic thermometers operated for radiation hardness tests of several piezoelectric actuators at T~4.2 K. This new apparatus

Paris-Sud XI, Université de

50

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

51

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

52

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

53

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

54

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

55

Transverse surface waves in a layered structure with a functionally graded piezoelectric substrate and a hard dielectric layer.  

PubMed

As to an ideally layered structure with a functionally graded piezoelectric substrate (material parameters change continuously along the thickness direction) and a hard dielectric layer, the existence and propagation behavior of transverse surface waves is studied by analytical technique. The dispersion equations for the existence of the transverse surface waves with respect to phase velocity are obtained for electrically open and short circuit conditions, respectively. A detailed investigation of the effect of gradient coefficient on dispersion relation, electromechanical coupling factor and penetration depth is carried out. It is found by numerical examples that adjusting gradient coefficient makes the electromechanical coupling factor of the transverse surface waves achieve quite high values at some appropriate ratio values of the layer thickness to the wavelength, and at the same time, the penetration depth can be reduced to the same order as the wavelength. PMID:19036395

Qian, Zheng-Hua; Jin, Feng; Lu, Tianjian; Kishimoto, Kikuo

2009-03-01

56

Development of piezoelectric adaptive mirror for hard x-ray nanofocusing  

NASA Astrophysics Data System (ADS)

To construct an adaptive X-ray focusing optical system, we developed an ultraprecise deformable mirror that consists of a substrate, piezoelectric actuators, and 18 electrodes. A one-dimensional focusing test was performed at SPring-8 at 15 keV. The mirror deformation was roughly adjusted by applying voltages determined by a deformation test with a Fizeau interferometer. The shape was then finely corrected based on the shape determined by the pencil-beam method and the phase retrieval method. A focused beam with a full width at half maximum of 120 nm was obtained.

Matsuyama, S.; Kimura, T.; Nakamori, H.; Imai, S.; Sano, Y.; Kohmura, Y.; Tamasaku, K.; Yabashi, M.; Ishikawa, T.; Yamauchi, K.

2012-10-01

57

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

58

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

59

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

60

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

61

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

62

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

63

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

64

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

65

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

66

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

67

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

68

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

69

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

70

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

71

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

72

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

73

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

74

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

75

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

76

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

77

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

78

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

79

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

80

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

81

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

82

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

83

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

84

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

85

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

86

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

87

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

88

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

89

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

90

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

91

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

92

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

93

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

94

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

95

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

96

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

97

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

98

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

99

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

100

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

101

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

102

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

103

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...

104

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

105

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

106

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

107

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...

108

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

109

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

110

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

111

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 0.04piezoelectric 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

112

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

113

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

114

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

115

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

116

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

117

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

118

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

119

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

120

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

121

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

122

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

123

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

124

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

125

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

126

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

127

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

128

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

129

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

130

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

131

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

132

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

133

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.

134

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

135

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

136

"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

137

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

138

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

139

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

140

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

141

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

142

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

143

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

144

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

145

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

146

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

147

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

148

The Dependence on Temperature and Hydration of Piezoelectric, Dielectric and Elastic Constants of Bone  

Microsoft Academic Search

The piezoelectric, dielectric and elastic constants of bone are determined at 10 Hz from -150 to 150C. The piezoelectric constant of dry bone hardly depends on temperature. The piezoelectric constant of 7.4% hydrated bone is larger than that of dry bone at temperatures below 0C, but smaller at temperatures above 0C. The former is attributed to the increase of crystallinity

Hideatsu Maeda; Keishiro Tsuda; Eiichi Fukada

1976-01-01

149

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

150

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

151

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

152

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

153

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

154

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

155

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

156

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

157

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

158

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

159

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

160

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

161

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

162

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

163

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

164

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

165

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

166

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

167

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

168

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

169

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

170

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

171

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

172

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

173

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.

174

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

175

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

176

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

177

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

178

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

179

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

180

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

181

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

182

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

183

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

184

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

185

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

186

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

187

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

188

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

189

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

190

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

191

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

192

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

193

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

194

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

PubMed

For potassium-sodium niobate, the piezoelectric constant (d33) was usually improved by sacrificing the Curie temperature (TC). In this work, a material system of 0.992(K0.46Na0.54)0.965Li0.035Nb(1-x)Sb(x)O3-0.008BiScO3 has been designed and prepared with the aim of achieving both a large d33 and a high TC at the same time. The chemical compositions are found to be homogeneously distributed in the ceramics. The introduction of Sc is found to be responsible for different grain sizes. The rhombohedral-tetragonal phase coexistence zone lies in the composition range of 0.02piezoelectric applications. PMID:24219128

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

2013-11-13

195

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

196

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

197

Identification of elastic, dielectric, and piezoelectric constants in piezoceramic disks.  

PubMed

Three-dimensional modeling of piezoelectric devices requires a precise knowledge of piezoelectric material parameters. The commonly used piezoelectric materials belong to the 6mm symmetry class, which have ten independent constants. In this work, a methodology to obtain precise material constants over a wide frequency band through finite element analysis of a piezoceramic disk is presented. Given an experimental electrical impedance curve and a first estimate for the piezoelectric material properties, the objective is to find the material properties that minimize the difference between the electrical impedance calculated by the finite element method and that obtained experimentally by an electrical impedance analyzer. The methodology consists of four basic steps: experimental measurement, identification of vibration modes and their sensitivity to material constants, a preliminary identification algorithm, and final refinement of the material constants using an optimization algorithm. The application of the methodology is exemplified using a hard lead zirconate titanate piezoceramic. The same methodology is applied to a soft piezoceramic. The errors in the identification of each parameter are statistically estimated in both cases, and are less than 0.6% for elastic constants, and less than 6.3% for dielectric and piezoelectric constants. PMID:21156373

Perez, Nicolas; Andrade, Marco A B; Buiochi, Flavio; Adamowski, Julio C

2010-12-01

198

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

199

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

200

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

201

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

202

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

203

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

204

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

205

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

206

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

207

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

208

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

209

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

210

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

211

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

212

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

213

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

214

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

215

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

216

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.

217

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

218

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

219

Aeroservoelastic DAP missile fin development. [directionally attached piezoelectric actuator  

NASA Technical Reports Server (NTRS)

The development of an active aeroservoelastic missile fin using directionally attached piezoelectric (DAP) actuator elements is detailed. Several different types of actuator elements are examined, including piezoelectric polymers, piezoelectric fiber composites, and conventionally attached piezoelectric (CAP) and DAP elements. These actuator elements are bonded to the substrate of a torque plate. The root of the torque plate is attached to a fuselage hard point or folding pivot. The tip of the plate is bonded to an aerodynamic shell which undergoes a pitch change as the plate twists. The design procedures used on the plate are discussed. A comparison of the various actuator element shows that DAP elements provide the highest deflections with the highest torsional stiffness. A torque plate was constructed from 0.2032 mm thick DAP elements bonded to a 0.127 mm thick AISI 1010 steel substrate. The torque plate produced static twist deflections in excess of +/- 3 deg. An aerodynamic shell with a modified NACA 0012 profile was added to the torque plate. This fin was tested in a wind tunnel at speeds up to 50 ms/sec. The static deflection of the fin was predicted to within 6 percent of the experimental data.

Barrett, Ron

1993-01-01

220

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

221

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.

222

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.

223

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

224

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.

225

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

226

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

227

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

228

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

229

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

230

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

231

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

232

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

233

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

234

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

235

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

236

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

237

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

238

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.

239

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

240

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

241

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

242

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

243

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

244

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

245

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

246

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

247

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

248

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

249

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.

250

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

251

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

252

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

253

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

254

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

255

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

256

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

257

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

258

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

259

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

260

Optical piezoelectric transducer for nano-ultrasonics  

Microsoft Academic Search

Piezoelectric semiconductor strained layers can be treated as piezoelectric transducers to generate nanometer-wavelength and THz-frequency acoustic waves. The mechanism of nano-acoustic wave (NAW) generation in strained piezoelectric layers, induced by femtosecond optical pulses, can be modeled by a macroscopic elastic continuum theory. The optical absorption change of the strained layers modulated by NAW through quantum-confined Franz-Keldysh (QCFK) effects allows optical

Kung-Hsuan Lin; Gia-Wei Chern; Cheng-Ta Yu; Tzu-Ming Liu; Chang-Chi Pan; Guan-Ting Chen; Jen-Inn Chyi; Sheng-Wen Huang; Pai-Chi Li; Chi-Kuang Sun

2005-01-01

261

Additional Drive Circuitry for Piezoelectric Screw Motors  

NASA Technical Reports Server (NTRS)

Modules of additional drive circuitry have been developed to enhance the functionality of a family of commercially available positioning motors (Picomotor . or equivalent) that provide linear motion controllable, in principle, to within increments .30 nm. A motor of this type includes a piezoelectric actuator that turns a screw. Unlike traditional piezoelectrically actuated mechanisms, a motor of this type does not rely on the piezoelectric transducer to hold position: the screw does not turn except when the drive signal is applied to the actuator.

Smythe, Robert; Palmer, Dean; Gursel, Yekta; Reder, Leonard; Savedra, Raymond

2004-01-01

262

Piezoelectric field in strained GaAs.  

SciTech Connect

This report describes an investigation of the piezoelectric field in strained bulk GaAs. The bound charge distribution is calculated and suitable electrode configurations are proposed for (1) uniaxial and (2) biaxial strain. The screening of the piezoelectric field is studied for different impurity concentrations and sample lengths. Electric current due to the piezoelectric field is calculated for the cases of (1) fixed strain and (2) strain varying in time at a constant rate.

Chow, Weng Wah; Wieczorek, Sebastian Maciej

2005-11-01

263

Piezoelectrically actuated dome-shaped diaphragm micropump  

Microsoft Academic Search

This paper describes a piezoelectric micropump built on a dome-shaped diaphragm with one-way parylene valves. The micropump uses piezoelectric ZnO film (less than 10 ?m thick) to actuate a parylene dome diaphragm, which is fabricated with an innovative, IC-compatible process on a silicon substrate. Piezoelectric ZnO film is sputter-deposited on a parylene dome diaphragm with its C-axis oriented perpendicular to

Guo-Hua Feng; Eun Sok Kim

2005-01-01

264

Polarization and Characterization of Piezoelectric Polymers  

NASA Technical Reports Server (NTRS)

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

Bodiford, Hollie N.

1995-01-01

265

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

266

Biocompatible Nanogenerators through High Piezoelectric Coefficient 0.5Ba(Zr0.2 Ti0.8 )O3 -0.5(Ba0.7 Ca0.3 )TiO3 Nanowires for In-Vivo Applications.  

PubMed

Lead-free BZT-BCT (0.5Ba(Zr0.2 Ti0.8 )O3 -0.5(Ba0.7 Ca0.3 )TiO3 ) nanowires with a high piezoelectric coefficient are synthesized and nanogenerators (NGs) composed of them are successfully developed. The studied in vitro and in vivo biocompatibility of the NGs shows great potential for their application as in vivo power sources. PMID:25257019

Yuan, Miaomiao; Cheng, Li; Xu, Qi; Wu, Weiwei; Bai, Suo; Gu, Long; Wang, Zhe; Lu, Jun; Li, Huanping; Qin, Yong; Jing, Tao; Wang, Zhong Lin

2014-11-01

267

Piezoelectric Generator for Powering Remote Sensing Networks  

E-print Network

This paper deals with the design, modeling and experimental validation of a piezoelectric harvest ambient energy generator based on ambient vibrations to be used in remote and long-term sensing networks. Simulations and experimental studies validate the functionality of individual components in an integrated piezoelectric generator unit.

unknown authors

268

On the Piezoelectric Effect of Bone  

Microsoft Academic Search

The piezoelectric effect of bone has been observed similarly to the case of wood or ramie. The specimens were cut out from the femur of man and ox, and dried completely by heating. The piezoelectric constants were measured by three different experiments, that is, measurements of the static direct effect, the dynamic direct effect and the dynamic converse effect. The

Eiichi Fukada; Iwao Yasuda

1957-01-01

269

Piezoelectric resonators for RF and microwave filters  

NASA Astrophysics Data System (ADS)

The interest of piezoelectric materials for Radio Frequency and Microwave applications is presented. Simulation and characterization results of RF band pass filter formed by five piezoelectric Film Bulk Acoustic Resonators for UMTS wireless communication applications are carried out and showed in this work.

Mabrouk, M.; Boujema, M. A.; Ndagijimana, F.; Benech, P.; Ghazel, A.

2010-11-01

270

Design and testing of piezoelectric sensors  

E-print Network

to the polyvinylidene fluoride (PVDF) ...................................2 I.3 Piezoelectric behavior overview..................................................................7 I.4 Piezoelectric mechanism research............................. ...................................................................................................... 97 viii LIST OF FIGURES Page Figure 1 Polyvinylidene fluoride molecule....................................................................... 3 Figure 2 Diagrams of (a) ?-phase and (b) ?-phase chain conformations in PVDF...

Mika, Bartosz

2009-05-15

271

LC Circuits for Diagnosing Embedded Piezoelectric Devices  

NASA Technical Reports Server (NTRS)

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

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

2005-01-01

272

Piezoelectric circular microdiaphragm based pressure sensors  

Microsoft Academic Search

Pressure influences on the vibration characteristics of piezoelectric circular microdiaphragm based pressure sensors are investigated theoretically and experimentally. It was demonstrated that only Bessel function of zero order, m=0, participates in the vibration modes of the microdiaphragm symmetrically loaded by pressure. The piezoelectric circular microdiaphragm was fabricated by combining solgel PZT thin film and MEMS technology. A high value of

M. Olfatnia; T. Xu; J. M. Miao; L. S. Ong; X. M. Jing; L. Norford

2010-01-01

273

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

274

Multimodal Passive Vibration Suppression with Piezoelectric Materials and Resonant Shunts  

Microsoft Academic Search

Passive piezoelectric damping devices are studied. These devices, consisting of a piezoelectric element and a resonant shunt, are analogous to mechanical damped vibration ab sorbers. In the past, a single piezoelectric device has been used to suppress a single structural mode. In this paper, the theory is expanded so that a single piezoelectric element can be used to suppress multiple

Joseph J. Hollkamp

1994-01-01

275

Analysis of thin piezoelectric solids by the boundary element method  

E-print Network

Analysis of thin piezoelectric solids by the boundary element method Yijun Liu*, Hui Fan Department February 2001; received in revised form 1 October 2001 Abstract The piezoelectric boundary integral equation (BIE) formulation is applied to analyze thin piezoelectric solids, such as thin piezoelectric

Liu, Yijun

276

BLOOD FLOW RATE MEASUREMENT BY USING NANO-PIEZOELECTRIC SENSOR  

E-print Network

This study was to Design a setup used to measure the flow using piezoelectric sensor for medical purposes using the property of piezoelectricity. The piezoelectric disc used is shown below. Two/ four piezoelectric discs were placed in line, inclined or parallel on a flexi tube (ACLYRIC)and the outputs observed for various waveforms and levels of water to measure the direction of Fluid.

unknown authors

277

Piezoelectric and Semiconducting Coupled Power Generating Process of a  

E-print Network

Piezoelectric and Semiconducting Coupled Power Generating Process of a Single ZnO Belt observation of piezoelectric generation from a single ZnO wire/belt for illustrating a fundamental process and stored by piezoelectric potential, and later converts into piezoelectric energy. The mechanism

Wang, Zhong L.

278

Piezoelectric Windmill: A Novel Solution to Remote Sensing  

Microsoft Academic Search

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

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

2005-01-01

279

A piezoelectric cryogenic heat switch  

NASA Astrophysics Data System (ADS)

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

Jahromi, Amir E.; Sullivan, Dan F.

2014-06-01

280

A piezoelectric cryogenic heat switch.  

PubMed

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

Jahromi, Amir E; Sullivan, Dan F

2014-06-01

281

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

NASA Astrophysics Data System (ADS)

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

Ramirez, Mauricio; Henneken, Lothar; Virtanen, Sannakaisa

2011-05-01

282

Using Diffusion Bonding in Making Piezoelectric Actuators  

NASA Technical Reports Server (NTRS)

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

Sager, Frank E.

2003-01-01

283

Steerable Adaptive Bullet (StAB) piezoelectric flight control system  

NASA Astrophysics Data System (ADS)

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

Barrett, Ron; Barnhart, Ryan; Bramlette, Richard

2012-04-01

284

Wear of hard materials by hard particles  

SciTech Connect

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

Hawk, Jeffrey A.

2003-10-01

285

Hardness testing. 2nd edition  

SciTech Connect

This basic book provides a comprehensive overview of hardness testing, including the various methods and equipment used, testing applications, and the selection of testing methods. The revised and updated second edition features expanded information on microhardness testing, specialized hardness tests; and hardness testing standards. Contents include: introduction to hardness testing; brinell testing; rockwell hardness testing; vickers hardness testing; microhardness testing; scleroscope and leeb hardness testing; hardness testing applications; and selection of hardness testing methods.

Chandler, H. [ed.

1999-07-01

286

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

287

Miniature Piezoelectric Macro-Mass Balance  

NASA Technical Reports Server (NTRS)

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

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

2010-01-01

288

Piezoelectric voltage coupled reentrant cavity resonator  

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

289

A traveling wave piezoelectric beam robot  

NASA Astrophysics Data System (ADS)

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

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

2014-02-01

290

Piezoelectric voltage coupled reentrant cavity resonator.  

PubMed

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

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

2014-10-01

291

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

292

A nanoscale piezoelectric transformer for low-voltage transistors.  

PubMed

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

Agarwal, Sapan; Yablonovitch, Eli

2014-11-12

293

Variational Asymptotic Micromechanics Modeling of Heterogeneous Piezoelectric  

E-print Network

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

Yu, Wenbin

294

Piezoelectric nanoparticle-polymer composite foams.  

PubMed

Piezoelectric polymer composite foams are synthesized using different sugar-templating strategies. By incorporating sugar grains directly into polydimethylsiloxane mixtures containing barium titanate nanoparticles and carbon nanotubes, followed by removal of the sugar after polymer curing, highly compliant materials with excellent piezoelectric properties can be fabricated. Porosities and elasticity are tuned by simply adjusting the sugar/polymer mass ratio which gave an upper bound on the porosity of 73% and a lower bound on the elastic coefficient of 32 kPa. The electrical performance of the foams showed a direct relationship between porosity and the piezoelectric outputs, giving piezoelectric coefficient values of ?112 pC/N and a power output of ?18 mW/cm(3) under a load of 10 N for the highest porosity samples. These novel materials should find exciting use in a variety of applications including energy scavenging platforms, biosensors, and acoustic actuators. PMID:25353687

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

2014-11-26

295

Piezoelectric Energy Harvesting From Flutter  

NASA Astrophysics Data System (ADS)

With the increasing need for alternative sources of energy, a great deal of attention is drawn to harvesting energy from ambient vibration. These vibrations may be caused by fluid forces acting upon a structure. When a flexible structure is subject to a fluid flow, it loses stability at a certain flow velocity and starts to vibrate. This self-induced motion is called flutter where energy is continuously transferred from the fluid to the structure. In this study a piezoelectric film sensor is used as a fluttering object, to convert the motion to electrical energy, and the energy harvesting capacity of the proposed concept is investigated. An experimental setup, composed of data acquisition methods, is designed and the findings are validated by original test data. The results are also compared to similar literature and it is concluded that the proposed energy harvesting technique meets the requirements of the intended application.

Norouzi, Soroush

296

Get the LEAD Out!Most lead-containing autoclave tape has stripes running across at an angle ( / / / / / / ); if it has very faint text (the word "autoclaved"), it most likely is a lead-free alternative.  

E-print Network

Get the LEAD Out!Most lead-containing autoclave tape has stripes running across at an angle ( / / / / / / ); if it has very faint text (the word "autoclaved"), it most likely is a lead-free alternative. ADDITIONAL Programs Office (650.723.0110) REPLACE lead-containing rolls of auto- clave tape with a non-lead containing

Ford, James

297

Passive modal damping with piezoelectric shunts  

SciTech Connect

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

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

2001-01-01

298

Measuring droplet impact with piezoelectric film  

E-print Network

Droplet Impact With Piezoelectric Film. (December 1993) Jalal M. Al-Badry Basahi, B. S. , King Saudi University, Saudi Arabia Chair of Advisory Committee: Dr. Guy Fipps The objective of this research was to develop a measurement system... Droplet Impact With Piezoelectric Film. (December 1993) Jalal M. Al-Badry Basahi, B. S. , King Saudi University, Saudi Arabia Chair of Advisory Committee: Dr. Guy Fipps The objective of this research was to develop a measurement system...

Basahi, Jalal M. Al-Badry M.

2012-06-07

299

Piezoelectric cantilever voltage-to-frequency converter  

Microsoft Academic Search

A micromachined piezoelectric cantilever acoustic device that functions as a microspeaker and a voltage-to-frequency converter has been designed, fabricated and tested. The 2 2 0.0047 mm3 cantilever has a 1.3-?m-thick zinc oxide (ZnO) piezoelectric thin film on a supporting layer of LPCVD low-stress silicon nitride. When measured with 8 VP-P (peak-peak) input drive, the sound pressure level (SPL)

Seung S. Lee; Richard M. White

1998-01-01

300

Piezoelectric properties of PZT films for microcantilever  

Microsoft Academic Search

The investigation of piezoelectric properties of materials in the thin layer form has become an important task because of the increased range of their applications as actuators and sensors. The sensor magnitude, is a direct function of the e31 piezoelectric constant. Pb(Zr,Ti)O3 thin films and the modified compositions have attracted great attention in recent years as promising for use in

E. Cattan; T. Haccart; G. Vlu; D. Rmiens; C. Bergaud; L. Nicu

1999-01-01

301

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

302

How Hard is Chocolate?  

NSDL National Science Digital Library

Hardness is probably a concept you are well familiar with. You already know that certain materials are harder than others; in fact, you prove it everyday when you chew your food and your teeth don’t break (because your teeth are harder than the foods you chew). Hardness can be defined as a material's ability to resist a change in shape. Modern hardness testers take a well-defined shape and press it into a material with a certain force, observing the indent it leaves in the material when it is removed. In this lesson, you will be performing hardness testing on different bars of chocolate.

2007-12-20

303

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

304

5118 IEEE TRANSACTIONS ON MAGNETICS, VOL. 45, NO. 11, NOVEMBER 2009 Enhanced Vibration Suppression in Hard Disk Drives  

E-print Network

for cancellation of common non-off-track modes in the measurement. Thin-film ZnO strain sensors have been to evaluate the use of high-resolution thin-film strain sensors for vibration sup- pression in hard disk disk drive servos, multisensor systems, piezoelectric thin films. I. INTRODUCTION I NDUSTRY goals

Horowitz, Roberto

305

1708 IEEE SENSORS JOURNAL, VOL. 13, NO. 5, MAY 2013 Integration of Thin Film Strain Sensors Into Hard  

E-print Network

of piezoelectric thin-film sensing technology by incorporating ZnO strain sensors into a hard disk drive (HDD) and deploying the sensors in a high-sample-rate feedback controller to suppress vibrations. First, thin-film ZnO1708 IEEE SENSORS JOURNAL, VOL. 13, NO. 5, MAY 2013 Integration of Thin Film Strain Sensors

Horowitz, Roberto

306

Session: Hard Rock Penetration  

SciTech Connect

This session at the Geothermal Energy Program Review X: Geothermal Energy and the Utility Market consisted of five presentations: ''Hard Rock Penetration - Summary'' by George P. Tennyson, Jr.; ''Overview - Hard Rock Penetration'' by James C. Dunn; ''An Overview of Acoustic Telemetry'' by Douglas S. Drumheller; ''Lost Circulation Technology Development Status'' by David A. Glowka; ''Downhole Memory-Logging Tools'' by Peter Lysne.

Tennyson, George P. Jr.; Dunn, James C.; Drumheller, Douglas S.; Glowka, David A.; Lysne, Peter

1992-01-01

307

Hardness Tester for Polyur  

NASA Technical Reports Server (NTRS)

Rubber-hardness tester modified for use on rigid polyurethane foam. Provides objective basis for evaluation of improvements in foam manufacturing and inspection. Typical acceptance criterion requires minimum hardness reading of 80 on modified tester. With adequate correlation tests, modified tester used to measure indirectly tensile and compressive strengths of foam.

Hauser, D. L.; Buras, D. F.; Corbin, J. M.

1987-01-01

308

Memory Hard Drive Peripherals  

E-print Network

1! CSI3131 Topics CPU Memory Hard Drive Peripherals Computing Systems OS Overview StructureDeadlocks M em ory M anagem ent Basic Memory Managermtn Virtual Memory Storage and I/O File Systems Hard Drive Management Swap I/O Management 2 Module 7: Memory Management Reading: Chapter 8 § To provide a detailed

Stojmenovic, Ivan

309

Model of a Piezoelectric Transducer  

NASA Technical Reports Server (NTRS)

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

Goodenow, Debra

2004-01-01

310

Thermal Analysis of Piezoelectric Benders with Laminated Power Electronics  

E-print Network

Thermal Analysis of Piezoelectric Benders with Laminated Power Electronics Andrew J. Fleming1 with integrated high voltage power electronics. Such devices dramatically simplify the application of piezoelectric actuators since the power electronics are already optimized for the voltage range, capacitance

Fleming, Andrew J.

311

Piezoelectric biosensor with a ladder polymer substrate coating  

DOEpatents

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

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

1998-01-01

312

Multilayer Piezoelectric Stack Actuator Characterization  

NASA Technical Reports Server (NTRS)

Future NASA missions are increasingly seeking to use actuators for precision positioning to accuracies of the order of fractions of a nanometer. For this purpose, multilayer piezoelectric stacks are being considered as actuators for driving these precision mechanisms. In this study, sets of commercial PZT stacks were tested in various AC and DC conditions at both nominal and extreme temperatures and voltages. AC signal testing included impedance, capacitance and dielectric loss factor of each actuator as a function of the small-signal driving sinusoidal frequency, and the ambient temperature. DC signal testing includes leakage current and displacement as a function of the applied DC voltage. The applied DC voltage was increased to over eight times the manufacturers' specifications to investigate the correlation between leakage current and breakdown voltage. Resonance characterization as a function of temperature was done over a temperature range of -180C to +200C which generally exceeded the manufacturers' specifications. In order to study the lifetime performance of these stacks, five actuators from one manufacturer were driven by a 60volt, 2 kHz sine-wave for ten billion cycles. The tests were performed using a Lab-View controlled automated data acquisition system that monitored the waveform of the stack electrical current and voltage. The measurements included the displacement, impedance, capacitance and leakage current and the analysis of the experimental results will be presented.

Sherrit, Stewart; Jones, Christopher M.; Aldrich, Jack B.; Blodget, Chad; Bao, Xioaqi; Badescu, Mircea; Bar-Cohen, Yoseph

2008-01-01

313

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

314

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

315

Active Piezoelectric Energy Harvesting: General Principle and Experimental Demonstration  

Microsoft Academic Search

In piezoelectric energy harvesting systems, the energy harvesting circuit is the interface between a piezoelectric device and an electrical load. A conventional view of this interface is based on impedance matching concepts. In fact, an energy harvesting circuit can also apply electrical boundary conditions, such as voltage and charge, to the piezoelectric device for each energy conversion cycle. An optimized

Yiming Liu; Geng Tian; Yong Wang; Junhong Lin; Qiming Zhang; Heath F. Hofmann

2009-01-01

316

Piezoelectric Properties of Non-Polar Block Copolymers  

SciTech Connect

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

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

2011-01-01

317

Piezoelectric Characterization of Individual Zinc Oxide Nanobelt Probed  

E-print Network

Piezoelectric Characterization of Individual Zinc Oxide Nanobelt Probed by Piezoresponse Force piezoelectric coefficient (d33) of an individual (0001) surface dominated zinc oxide nanobelt lying on a conductive surface. Based on references of bulk (0001) ZnO and x-cut quartz, the effective piezoelectric

Wang, Zhong L.

318

ON THE DIFFERENCE BETWEEN DIELECTRIC AND PIEZOELECTRIC RELAXATION  

E-print Network

771 ON THE DIFFERENCE BETWEEN DIELECTRIC AND PIEZOELECTRIC RELAXATION K. NISHINARI National Food and piezoelectric relaxations are treated in the same way by the two-site model in order to clarify the difference is essentially important in the piezoelectric case. The frequency and temperature dependence is discussed

Paris-Sud XI, Université de

319

Piezoelectric-Potential-Controlled Polarity-Reversible Schottky Diodes and  

E-print Network

Piezoelectric-Potential-Controlled Polarity-Reversible Schottky Diodes and Switches of ZnO WiresVersity, 100084 Beijing, China Received August 14, 2008 ABSTRACT Using a two-end bonded ZnO piezoelectric-induced piezoelectric potential-drop along the PFW, which have been quantified using the thermionic emission

Wang, Zhong L.

320

Technical Communication Piezoelectric Vibrating Needle and Catheter for  

E-print Network

Technical Communication Piezoelectric Vibrating Needle and Catheter for Enhancing Ultrasound) were customized by adhering in place two piezoelectric actuators. These created 1­8 kHz vibrations when of the needle or catheter tip would be helpful. We describe a piezoelectric needle and catheter design

Smith, Stephen

321

Estimation of parameters of thin plates excited by piezoelectric patches  

E-print Network

Estimation of parameters of thin plates excited by piezoelectric patches N.D. Botkin Institute by patches made of piezoelectric materials. The first, linear, model is well known and is in details in is illustrated by computer simulations. Keywords: Linear thin plates, Nonlinear thin plates, Piezoelectric

Botkin, Nikolai

322

Analysis of microstructural elds in heterogeneous piezoelectric solids  

E-print Network

Analysis of microstructural ®elds in heterogeneous piezoelectric solids J.Y. Li, M.L. Dunn * Center is developed to analyze the internal ®elds in heterogeneous piezoelectric solids. It is used to derive the general development, the theory is applied to multiphase matrix-based piezoelectric composites

Li, Jiangyu

323

A Domain Wall Model for Hysteresis in Piezoelectric Materials  

E-print Network

A Domain Wall Model for Hysteresis in Piezoelectric Materials Ralph C. Smith Center for Research design. i #12; 1 Introduction Piezoelectric materials provide the capability for designing actuators piezoelectric effects. As a result of the ferroelectric nature of the materials, they also exhibit varying

324

Subnanosecond piezoelectric x-ray switch Alexei Grigoriev,a  

E-print Network

Subnanosecond piezoelectric x-ray switch Alexei Grigoriev,a Dal-Hyun Do, Dong Min Kim, Chang online 12 July 2006 We report an ultrafast piezoelectric switch for synchrotron x rays. A thin epitaxial film of piezoelectric Pb Zr,Ti O3 works as a diffractive optical switch at frequencies from dc to 1 GHz

Eom, Chang Beom

325

Force control in piezoelectric microactuators using self scheduled H technique  

E-print Network

Force control in piezoelectric microactuators using self scheduled H technique Micky Rakotondrabe the manipulation force applied by piezoelectric microactuators by using a parameter dependent approach of the piezoelectric microactuator was compensated and the derived model is therefore linear. Afterwards, we design

Boyer, Edmond

326

Analog Sliding Mode Controller for Position Tracking of Piezoelectric Actuators  

E-print Network

Analog Sliding Mode Controller for Position Tracking of Piezoelectric Actuators S. Yannier and A) of piezoelectric actuators is presented. DSP application of the algorithm suffers from ADC and DAC conversions and faces speed limitations. Moreover, piezoelectric actuators are known to have very large bandwidth close

Yanikoglu, Berrin

327

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

328

Piezoelectric Wafer Active Sensor Embedded Ultrasonics in Beams and Plates  

E-print Network

Piezoelectric Wafer Active Sensor Embedded Ultrasonics in Beams and Plates by V. Giurgiutiu, J. Bao and experimental investigation of the fun- damental aspects of using piezoelectric wafer active sensors (PWASs of these results to in situ structural health monitoring using embedded ultrasonics. KEY WORDS--Piezoelectric

Giurgiutiu, Victor

329

CHECK OF PIEZOELECTRIC TRANSDUCERS USING THE ELECTRO-MECHANICAL IMPEDANCE  

E-print Network

CHECK OF PIEZOELECTRIC TRANSDUCERS USING THE ELECTRO- MECHANICAL IMPEDANCE Inka Buethe1 , Maria Braunschweig, Germany inka.buethe@uni-siegen.de ABSTRACT The use of piezoelectric wafer active sensors of a piezoelectric patch transducer, directly embedded in the structure, was tested. It has been shown

Paris-Sud XI, Université de

330

EFFECT OF TEMPERATURE ON VIBRATIONS OF PHYSICALLY NONLINEAR PIEZOELECTRIC RODS  

E-print Network

EFFECT OF TEMPERATURE ON VIBRATIONS OF PHYSICALLY NONLINEAR PIEZOELECTRIC RODS Victor Birman is concerned with a physically nonlinear behavior of piezoelectric rods. Such rods are often employed as transducers. We evaluate the effect of a uniformly distributed temperature on vibrations of a piezoelectric

Paris-Sud XI, Université de

331

NONLINEAR DYNAMICS OF A CANTILEVER BEAM ACTUATED BY PIEZOELECTRIC LAYERS  

E-print Network

NONLINEAR DYNAMICS OF A CANTILEVER BEAM ACTUATED BY PIEZOELECTRIC LAYERS IN SYMMETRIC Dynamics of a Cantilever Beam Actuated by Piezoelectric Layers in Symmetric and Asymmetric Configuration K Abstract The nonlinear equations of motion for a cantilever beam, covered by piezoelectric PZT layers

Rimon, Elon

332

The principle of correspondence between elastic and piezoelectric problems  

E-print Network

The principle of correspondence between elastic and piezoelectric problems E. Karapetian, M and piezoelectric prob- lems for transversely isotropic materials, in such a way that the knowledge of an elastic solution yields fully coupled electro­elastic fields for the corresponding piezoelectric problem, provided

Sevostianov, Igor

333

Hybrid Piezoelectric Harvester Tian-Bing Xu1  

E-print Network

Hybrid Piezoelectric Harvester Tian-Bing Xu1 , Emilie J. Siochi2 , Xiaoning Jiang3 , Ji Su2 , Lei Zuo4 , Wanlu Zhou4 , Paul Rehrig5 and Welsey Hackenberge5 An innovative hybrid piezoelectric energy-amplification of two types of piezoelectric multilayer elements to couple more mechanical energy, produce more

Zuo, Lei

334

Driving Forces for Interfacial Fatigue Crack Growth by Piezoelectric Actuator  

E-print Network

Driving Forces for Interfacial Fatigue Crack Growth by Piezoelectric Actuator MING LIU 1,3 , K. and Shang, J.K. 2001. ``Piezoelectric Actuation of Crack Growth along Polymer�Metal Interfaces in Adhesive Bonds,'' Journal of Material Research, 16(10):2885�2892). Using a piezoelectric actuator, cyclic loading

Hsia, K Jimmy

335

Low-power piezoelectric micro-machined valve  

NASA Technical Reports Server (NTRS)

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

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

2010-01-01

336

Switching Delay Effects on Nonlinear Piezoelectric Energy Harvesting Techniques  

Microsoft Academic Search

Energy harvesting using piezoelectric elements re- ceived much attention as vibrations are widely available and as piezoelectric transducers feature high-power densities and promising integration potentials. It has also been shown that applying a nonlinear treatment on the output voltage of the piezo- electric material can significantly enhance the performance of the device. This process consists of inverting the piezoelectric voltage

Mickal Lallart; Yi-Chieh Wu; Daniel Guyomar

2012-01-01

337

Characterization of a Piezoelectric Buzzer Using a Michelson Interferometer  

ERIC Educational Resources Information Center

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

Lloyd, S.; Paetkau, M.

2010-01-01

338

Semiactive and Active Piezoelectric Vibration Controls for Switched Reluctance Machine  

Microsoft Academic Search

This paper presents two vibration control approaches using piezoelectric inserts applied to a switched reluctance machine (SRM) in order to reduce acoustic emission. The semiactive approach, called synchronized switch damping, consists of a particular voltage processing that increases the electromechanical energy conversion of the piezoelectric insert and leads to effective vibration energy dissipation. Piezoelectric inserts can also be considered as

Xavier Mininger; Elie Lefeuvre; Mohamed Gabsi; Claude Richard; Daniel Guyomar

2008-01-01

339

Piezoresistive and Piezoelectric MEMS Strain Sensors for Vibration Detection  

E-print Network

Piezoresistive and Piezoelectric MEMS Strain Sensors for Vibration Detection Stanley Kona, Kenn are compared to those of piezoelectric sensors. Experimental results reveal that the MEMS piezoelectric sensors smaller areas. Both types of the MEMS strain sensors are capable of high sensitivity measurements, subject

Horowitz, Roberto

340

A novel method for the identification of inorganic and organic gunshot residue particles of lead-free ammunitions from the hands of shooters using scanning laser ablation-ICPMS and Raman micro-spectroscopy.  

PubMed

A method based on scanning laser ablation and inductively coupled plasma-mass spectrometry (SLA-ICPMS) and Raman micro-spectroscopy for the detection and identification of compounds consistent with gunshot residue particles (GSR) has been developed. The method has been applied to the characterization of particles resulting from the discharge of firearms using lead-free ammunition. Modified tape lifts were used to collect the inorganic and organic residues from skin surfaces in a single sample. Using SLA-ICPMS, aggregates related to the composition of the ammunition, such as Cu-Zn-Sn, Zr-Sr, Cu-Zn, Al-Ti, or Al-Sr-Zr were detected, but this composition is only consistent with GSR from lead-free ammunitions. Additional evidence was provided by micro-Raman spectroscopy, which identified the characteristic organic groups of the particles as centralite, diphenylamine or their nitrated derivatives, which are indicative of GSR. PMID:25303642

Abrego, Zurie; Grijalba, Nagore; Unceta, Nora; Maguregui, Maite; Sanchez, Alicia; Fernndez-Isla, Alberto; Goicolea, M Aranzazu; Barrio, Ramn J

2014-12-01

341

Multiferroism and Magnetoelectric Coupling in Nano-Microscale Lead-Free Composite by 0.3Co-FERRITE and 0.7(K0.5Na0.5)NbO3-BASED Ferroelectric Matrix  

NASA Astrophysics Data System (ADS)

Nontoxic lead-free multiferroic composites are synthesized by incorporating the dispersed 0.3CoFe2O4 (CFO) ferromagnetic nanoparticles into 0.7(K0.5Na0.5) NbO3-LiSbO3 (KNN-LS5.2) ferroelectric micromatrix. The multiferroicity of the composite can be verified by polarization-electric field hysteresis loop and magnetic hysteresis loop. The composite exhibits excellent magnetic properties. A dilution effect is observed in magnetic hysteresis loops. The field dependence of ME voltage coefficient is given as a function of magnetic field from -4 kOe to 4 kOe with a maximum magnetoelectric voltage coefficient of 10.7 mV?cm-1?Oe-1 at the frequency of 1 kHz. It is a very high value in the lead-free magnetoelectric composites system for the potential use on multifunctional devices.

Zhou, Yun; Wang, Xinyan; Li, Li; Su, Yuling; Zhang, Jincang; Cao, Shixun

342

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

E-print Network

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

Kleinfeld, David

343

LAUDE et al.: SURFACE GREEN'S FUNCTION OF A PIEZOELECTRIC HALF-SPACE 1 Surface Green's function of a piezoelectric  

E-print Network

LAUDE et al.: SURFACE GREEN'S FUNCTION OF A PIEZOELECTRIC HALF-SPACE 1 Surface Green's function of a piezoelectric half-space Vincent Laude, Carlos F. Jerez-Hanckes, and Sylvain Ballandras Abstract-- The computation of the two-dimensional harmonic spatial-domain Green's function at the surface of a piezoelectric

Boyer, Edmond

344

Radial-Electric-Field Piezoelectric Diaphragm Pumps  

NASA Technical Reports Server (NTRS)

In a recently invented class of piezoelectric diaphragm pumps, the electrode patterns on the piezoelectric diaphragms are configured so that the electric fields in the diaphragms have symmetrical radial (along-the-surface) components in addition to through-the-thickness components. Previously, it was accepted in the piezoelectric-transducer art that in order to produce the out-of-plane bending displacement of a diaphragm needed for pumping, one must make the electric field asymmetrical through the thickness, typically by means of electrodes placed on only one side of the piezoelectric material. In the present invention, electrodes are placed on both sides and patterned so as to produce substantial radial as well as through-the-thickness components. Moreover, unlike in the prior art, the electric field can be symmetrical through the thickness. Tests have shown in a given diaphragm that an electrode configuration according to this invention produces more displacement than does a conventional one-sided electrode pattern. The invention admits of numerous variations characterized by various degrees of complexity. Figure 1 is a simplified depiction of a basic version. As in other piezoelectric diaphragm pumps of similar basic design, the prime mover is a piezoelectric diaphragm. Application of a suitable voltage to the electrodes on the diaphragm causes it to undergo out-of-plane bending. The bending displacement pushes a fluid out of, or pulls the fluid into, a chamber bounded partly by the diaphragm. Also as in other diaphragm pumps in general, check valves ensure that the fluid flows only in through one port and only out through another port.

Bryant, Robert G.; Working, Dennis C.; Mossi, Karla; Castro, Nicholas D.; Mane, Pooma

2009-01-01

345

Broadband pulsed flow using piezoelectric microjets  

NASA Astrophysics Data System (ADS)

A piezohydraulic microjet design and experimental results are presented to demonstrate broadband active flow control for applications on various aircraft structures including impinging jets, rotor blades, cavity bays, etc. The microjet actuator includes a piezoelectric stack actuator and hydraulic circuit that is used to throttle a 400 ?m diameter microjet using hydraulic amplification of the piezoelectric stack actuator. This system is shown to provide broadband pulsed flow actuation up to 800 Hz. Unsteady pressure measurements of the microjet's exit flow are coupled with high-speed phase imagery using micro-Schlieren techniques to quantify the flow field. These results are compared with in situ stack actuator displacements using strain gauge measurements.

Hogue, Joshua; Solomon, John; Hays, Michael; Alvi, Farrukh; Oates, William

2010-04-01

346

Telescoping cylindrical piezoelectric fiber composite actuator assemblies  

NASA Technical Reports Server (NTRS)

A telescoping actuator assembly includes a plurality of cylindrical actuators in a concentric arrangement. Each cylindrical actuator is at least one piezoelectric fiber composite actuator having a plurality of piezoelectric fibers extending parallel to one another and to the concentric arrangement's longitudinal axis. Each cylindrical actuator is coupled to concentrically-adjacent ones of the cylindrical actuators such that the plurality of cylindrical actuators can experience telescopic movement. An electrical energy source coupled to the cylindrical actuators applies actuation energy thereto to generate the telescopic movement.

Allison, Sidney G. (Inventor); Shams, Qamar A. (Inventor); Fox, Robert L. (Inventor); Fox, legal representative, Christopher L. (Inventor); Fox Chattin, legal representative, Melanie L. (Inventor)

2010-01-01

347

Surface-Acoustic-Wave Piezoelectric Microbalance  

NASA Technical Reports Server (NTRS)

Improved piezoelectric microbalances developed for use in measuring masses of volcanic, aerosol, and other small particles suspended in air. Sensitive microbalance used to analyze airborne particles in real time in environments as diverse as clean rooms or upper atmosphere. Surface-acoustic-wave resonator includes input and output sets of interdigitated electrodes and two passive conductive patterns acting as reflectors. Mechanical energy travels both ways out from middle and reflected back toward middle. Microbalance and associated circuitry fit in small package. Circuit draws only 80 mA at 5 V. Sensitivity more than 400 times that of bulk piezoelectric microbalance.

Chuan, Raymond L.; Bowers, William D.

1992-01-01

348

Nanoindentation response of piezoelectric nano-islands  

NASA Astrophysics Data System (ADS)

Through three-dimensional finite element modeling, it is demonstrated that the nanoindentation response of piezoelectric nano-islands is strongly dependent on the shape of the nano-island and the depth of indentation. For indentations that are relatively deep (i.e., greater than 5% of the height of the islands), the substrate's elastic and plastic properties have a strong influence on the indentation response of piezoelectric nano-islands with substrate plasticity resulting in a significant reduction in the mechanical and electrical indentation stiffness. The predictions of the finite element models compare well with experiments on nano-islands of strontium-doped lead zirconate titanate.

Cheng, Guang; Sriram, Sharath; Bhaskaran, Madhu; Venkatesh, T. A.

2014-09-01

349

Nanogenerator comprising piezoelectric semiconducting nanostructures and Schottky conductive contacts  

NASA Technical Reports Server (NTRS)

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

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

2011-01-01

350

An ultrahigh sensitive self-powered current sensor utilizing a piezoelectric connected-in-series approach  

NASA Astrophysics Data System (ADS)

In this paper, we demonstrate a self-powered AC-current sensor using a piezoelectric connected-in-series approach to increase the sensitivity. The sensor consists of a CuBe-beam, piezoelectric-PZT-sheet, NdFeB hard-magnet, and mechanical-frame. When the sensor is placed in an alternative magnetic-field induced by an alternative current-carrying wire, the magnet fixed on the beam is subjected to an alternative magnetic-force produced by the magnetic-field. Therefore, the beam is oscillated. Consequently, the piezoelectric-sheet fixed on the beam is periodically deformed and continuously produces voltage-response. When beams are connected in-series, the total voltage-response is significantly enlarged while the background-noise remains the same. The experimental result shows the sensitivity of the sensor consisting 8 beams connected in-series under the magnetic-field generated by a wire of 8-Ampere from a breaker is enlarged from 130 mV/A to 640 mV/A.

Yeh, Po-Chen; Chung, Tien-Kan; Lai, Cheng-Huang

2014-03-01

351

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

352

An Examination of Applying Shunted Piezoelectrics to Reduce Aeroelastic Response  

NASA Technical Reports Server (NTRS)

Several analytical and experimental studies clearly demonstrate that piezoelectric materials (piezoelectrics) can be used as actuators to actively control vibratory response, including aeroelastic response. However, two important issues in using piezoelectrics as actuators for active control are: 1) the potentially large amount of power required to operate the actuators, and 2) the complexities involved with active control (added hardware, control law design, and implementation). Active or passive damping augmentation using shunted piezoelectrics may provide a viable alternative. This approach requires only simple electrical circuitry and very little or no electrical power. The current study examines the feasibility of using shunted piezoelectrics to reduce aeroelastic response using a typical-section representation of a wing and piezoelectrics shunted with a parallel resistor and inductor. The aeroelastic analysis shows that shunted piezoelectrics can effectively reduce aeroelastic response below flutter and may provide a simple, low-power method of subcritical aeroelastic control.

McGowan, Anna-Maria Rivas

1999-01-01

353

Characterization of piezoelectric materials with large piezoelectric and electromechanical coupling coefficients  

E-print Network

potential of these new single crystal piezoelectric materials in making ultra- sonic transducers and (1 ? x)Pb(Mg1=3Nb2=3)O3­xPbTiO3 single crystals pro- vided new challenges in property.84.-s; 77.84.Dy; 66.20.Dc Keywords: Material characterization; PZN­PT, PMN­PT piezoelectric crystals

Cao, Wenwu

354

Fabrication and characteristics of thin disc piezoelectric transformers based on piezoelectric buzzers with gap circles.  

PubMed

This paper investigates design, fabrication and test of thin disc piezoelectric transformers (PTs) based on piezoelectric buzzers with gap circles at different diameters of the gap circles. The performance test is focused on characteristics of voltage gains, including maximum voltage gains and maximum-gain frequencies, for each piezoelectric transformer under different load conditions. Both a piezoelectric buzzer and a gap circle on a silver electrode of the buzzer are needed to build any type of the PTs. Here, the gap circle is used to form a ring-shaped input electrode and a circle-shaped output electrode for each piezoelectric transformer. To do so, both structure and connection of a PT are first expressed. Then, operating principle of a PT and its related vibration mode observed by a carbon-power imaging technique are described. Moreover, an experimental setup for characterizing each piezoelectric transformer is constructed. Finally, effects of diameters of the gap circles on characteristics of voltage gains at different load resistances are discussed. PMID:18221977

Chang, Kuo-Tsai; Lee, Chun-Wei

2008-04-01

355

Pyroelectricity and piezoelectricity in nylon 11  

Microsoft Academic Search

This paper describes preliminary pyroelectric and piezoelectric results obtained with commercial films of nylon 11. The results of dielectric-constant measurements in the temperature range 20-130 C are also presented. Nylon 11 films show quite high pyroelectricity and the evidence indicates that there is probably dipole orientation in crystalline regions. Charge injection or volume polarization, as well as dipole orientation, was

Morton H. Litt; Che-Hsiung Hsu; P. Basu

1977-01-01

356

Designing piezoelectric films for micro electromechanical systems.  

PubMed

Piezoelectric thin films are of increasing interest in low-voltage micro electromechanical systems for sensing, actuation, and energy harvesting. They also serve as model systems to study fundamental behavior in piezoelectrics. Next-generation technologies such as ultrasound pill cameras, flexible ultrasound arrays, and energy harvesting systems for unattended wireless sensors will all benefit from improvements in the piezoelectric properties of the films. This paper describes tailoring the composition, microstructure, orientation of thin films, and substrate choice to optimize the response. It is shown that increases in the grain size of lead-based perovskite films from 75 to 300 nm results in 40 and 20% increases in the permittivity and piezoelectric coefficients, respectively. This is accompanied by an increase in the nonlinearity in the response. Band excitation piezoresponse force microscopy was used to interrogate the nonlinearity locally. It was found that chemical solution-derived PbZr(0.52)Ti(0.48)O(3) thin films show clusters of larger nonlinear response embedded in a more weakly nonlinear matrix. The scale of the clusters significantly exceeds that of the grain size, suggesting that collective motion of many domain walls contributes to the observed Rayleigh behavior in these films. Finally, it is shown that it is possible to increase the energy-harvesting figure of merit through appropriate materials choice, strong imprint, and composite connectivity patterns. PMID:21937309

Trolier-McKinstry, Susan; Griggio, Flavio; Yaeger, Charles; Jousse, Pierre; Zhao, Dalong; Bharadwaja, Srowthi S N; Jackson, Thomas N; Jesse, Stephen; Kalinin, Sergei V; Wasa, Kiyotaka

2011-09-01

357

Boundary conditions for axisymmetric piezoelectric cylinder  

NASA Astrophysics Data System (ADS)

For axisymmetric piezoelectric cylinder, the reciprocal theorem and the axisymmetric general solution of piezoelasticity are applied in a novel way to obtain the appropriate stress and mixed boundary conditions accurate to all orders for the cylinder of general edge geometry and loadings. A decay analysis technique developed by Gregory and Wan is converted into necessary conditions on the end-data of axisymmetric piezoelectric circular cylinder, and the rapidly decaying solution is established. The prescribed end-data of the circle cylinder must satisfy these conditions in order that they could generate a decaying state within the cylinder. When stress and mixed conditions are imposed on the end of cylinder, these decaying state conditions for the case of axisymmetric deformation of piezoelectric cylinder are derived explicitly. They are then used for the correct formulation of boundary conditions for the theory solution (or the interior solution) of axisymmetric piezoelectric cylinder. The results of the present paper enable us to establish a set of correct boundary conditions, most of which are obtained for the first time.

Zhao, Baosheng; Wu, Di; Chen, Xi

2013-12-01

358

Flow energy piezoelectric bimorph nozzle harvester  

NASA Astrophysics Data System (ADS)

There is a need for a long-life power generation scheme that could be used downhole in an oil well to produce 1 Watt average power. There are a variety of existing or proposed energy harvesting schemes that could be used in this environment but each of these has its own limitations. The vibrating piezoelectric structure is in principle capable of operating for very long lifetimes (decades) thereby possibly overcoming a principle limitation of existing technology based on rotating turbo-machinery. In order to determine the feasibility of using piezoelectrics to produce suitable flow energy harvesting, we surveyed experimentally a variety of nozzle configurations that could be used to excite a vibrating piezoelectric structure in such a way as to enable conversion of flow energy into useful amounts of electrical power. These included reed structures, spring mass-structures, drag and lift bluff bodies and a variety of nozzles with varying flow profiles. Although not an exhaustive survey we identified a spline nozzle/piezoelectric bimorph system that experimentally produced up to 3.4 mW per bimorph. This paper will discuss these results and present our initial analyses of the device using dimensional analysis and constitutive electromechanical modeling. The analysis suggests that an order-of-magnitude improvement in power generation from the current design is possible.

Sherrit, Stewart; Lee, Hyeong Jae; Walkemeyer, Phillip; Hasenoehrl, Jennifer; Hall, Jeffrey L.; Colonius, Tim; Tosi, Luis Phillipe; Arrazola, Alvaro; Kim, Namhyo; Sun, Kai; Corbett, Gary

2014-04-01

359

Development of MEMS piezoelectric energy harvesters  

Microsoft Academic Search

The research of powering devices in a microwatt range has been activated and developed by the emergence of low-power Very Large Scale Integration (VLSI) technology in the past few years. The powering devices require a size that is compatible with the application, sufficient power, and extended lifetime using permanent and ubiquitous energy sources. The piezoelectric energy harvester using vibration sources

Jung-Hyun Park

2010-01-01

360

Head waves in a piezoelectric half space  

Microsoft Academic Search

Head waves are an interesting phenomenon that is often ignored in harmonic piezoelectric wave study. They present a noise source in SAW devices, but carry useful information in seismology and ultrasonic NDE. In this work, a model based on exact Newtonian and Maxwell's equations of motion is used instead of the commonly used quasi-static approximation, because the former behaves better

Yuan Liu; Cheng-Hao Wang; C. F. Ying

1995-01-01

361

Designing Piezoelectric Films for Micro Electromechanical Systems  

SciTech Connect

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

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

2011-01-01

362

The constituent equations of piezoelectric heterogeneous bimorphs  

Microsoft Academic Search

The electromechanical characteristics of a heterogeneous piezoelectric bender subjected to various electrical and mechanical boundary conditions are discussed based on the results of the free bender analysis. The mechanical boundary conditions considered are: a mechanical moment at the end of the bender, a force applied perpendicularly to the tip of the bender, and a uniform load applied over the entire

Jan G. Smits; Wai-shing Choi

1991-01-01

363

Piezoelectric microactuator for dual stage control  

Microsoft Academic Search

This paper presents a piezoelectric-based microactuator concept that could provide an economical and easily integrated option for dual stage actuation used in rigid disk drives (RDDs). The design and operation of a prototype version is described. Manufacturability of the actuator and its integration in the RDD assembly is assessed. Approaches to providing the voltages required to drive the microactuator to

R. B. Evans; J. S. Griesbach; W. C. Messner

1999-01-01

364

Piezoelectric nanoribbons for monitoring cellular deformations  

E-print Network

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

Purohit, Prashant

365

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

366

The theory of a piezoelectric disc gyroscope  

Microsoft Academic Search

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

J. S. Burdess; T. Wren

1986-01-01

367

Dimensional Reduction of a Piezoelectric Composite Rod  

E-print Network

a piezoelectric material is its remarkable property to create a conversion interface between two forms of energy an equivalent one-dimensional electromechanical enthalpy is developed. Energy terms, which are asymptotically in numerous scientific fields. Ultrasonic technol- ogy, MEMS/NEMS industry, micro acoustic generator

Yu, Wenbin

368

Piezoelectric multilayer actuator life test.  

PubMed

Potential NASA optical missions such as the Space Interferometer Mission require actuators for precision positioning to accuracies of the order of nanometers. Commercially available multilayer piezoelectric stack actuators are being considered for driving these precision mirror positioning mechanisms. These mechanisms have potential mission operational requirements that exceed 5 years for one mission life. To test the feasibility of using these commercial actuators for these applications and to determine their reliability and the redundancy requirements, a life test study was undertaken. The nominal actuator requirements for the most critical actuators on the Space Interferometry Mission (SIM) in terms of number of cycles was estimated from the Modulation Optics Mechanism (MOM) and Pathlength control Optics Mechanism (POM) and these requirements were used to define the study. At a nominal drive frequency of 250 Hz, one mission life is calculated to be 40 billion cycles. In this study, a set of commercial PZT stacks configured in a potential flight actuator configuration (pre-stressed to 18 MPa and bonded in flexures) were tested for up to 100 billion cycles. Each test flexure allowed for two sets of primary and redundant stacks to be mechanically connected in series. The tests were controlled using an automated software control and data acquisition system that set up the test parameters and monitored the waveform of the stack electrical current and voltage. The samples were driven between 0 and 20 V at 2000 Hz to accelerate the life test and mimic the voltage amplitude that is expected to be applied to the stacks during operation. During the life test, 10 primary stacks were driven and 10 redundant stacks, mechanically in series with the driven stacks, were open-circuited. The stroke determined from a strain gauge, the temperature and humidity in the chamber, and the temperature of each individual stack were recorded. Other properties of the stacks, including the displacement from a capacitance gap sensor and impedance spectra were measured at specific intervals. The average degradation in the stroke over the life test was found to be small (<3%) for the primary stacks and <4% for the redundant stacks. It was noted that about half of the stroke reduction occurred within the first 10 billion cycles. At the end of the life test, it was found that the actuator could recover about half of the lost stroke by applying a dc voltage of 100 V at room temperature. The data up to 100 billion cycles for these tests and the analysis of the experimental results are presented in this paper. PMID:21507759

Sherrit, Stewart; Bao, Xiaoqi; Jones, Christopher M; Aldrich, Jack B; Blodget, Chad J; Moore, James D; Carson, John W; Goullioud, Renaud

2011-04-01

369

Modeling of a three-layer piezoelectric bimorph beam with hysteresis  

Microsoft Academic Search

Piezoelectric actuators are usually stacked or bimorph in configuration. In this paper the mechanics of a three-layer piezoelectric bimorph is discussed and its dynamic model with hysteresis is presented. The results can be used to analyze piezoelectric actuators constructed with three-layer piezoelectric bimorphs. A piezoelectric bimorph actuator has been fabricated and experiments have been carried out to verify the model.

T. S. Low; W. Guo

1995-01-01

370

Hard superconducting nitrides  

PubMed Central

Detailed study of the equation of state, elasticity, and hardness of selected superconducting transition-metal nitrides reveals interesting correlations among their physical properties. Both the bulk modulus and Vickers hardness are found to decrease with increasing zero-pressure volume in NbN, HfN, and ZrN. The computed elastic constants from first principles satisfy c11 > c12 > c44 for NbN, but c11 > c44 > c12 for HfN and ZrN, which are in good agreement with the neutron scattering data. The cubic ?-NbN superconducting phase possesses a bulk modulus of 348 GPa, comparable to that of cubic boron nitride, and a Vickers hardness of 20 GPa, which is close to sapphire. Theoretical calculations for NbN show that all elastic moduli increase monotonically with increasing pressure. These results suggest technological applications of such materials in extreme environments. PMID:15728352

Chen, Xiao-Jia; Struzhkin, Viktor V.; Wu, Zhigang; Somayazulu, Maddury; Qian, Jiang; Kung, Simon; Christensen, Axel N?rlund; Zhao, Yusheng; Cohen, Ronald E.; Mao, Ho-kwang; Hemley, Russell J.

2005-01-01

371

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

NASA Astrophysics Data System (ADS)

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

Toprak, Alperen; Tigli, Onur

2014-09-01

372

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

373

CSI: Hard Drive  

ERIC Educational Resources Information Center

Acting on information from students who reported seeing a classmate looking at inappropriate material on a school computer, school officials used forensics software to plunge the depths of the PC's hard drive, searching for evidence of improper activity. Images were found in a deleted Internet Explorer cache as well as deleted file space.

Sturgeon, Julie

2008-01-01

374

Generating Hard Satisfiability Problems  

Microsoft Academic Search

We report results from large-scale experiments in satisfiability testing. As has been observed by others, testing the satisfiability of random formulas often appears surprisingly easy. Here we show that by using the right distribution of instances, and appropriate parameter valu es, it is possible to generate random formulas that are hard, that is, for which satisfiability testing is quite difficult.

Bart Selman; David G. Mitchell; Hector J. Levesque

1996-01-01

375

Hard Sphere Gas Model  

NSDL National Science Digital Library

The Ejs Hard Sphere Gas model displays a three-dimensional (ideal) gas made out of hard disks. Particles are initialized with a random speed and in a random direction and move with constant velocity until a collision occurs. You can modify this simulation if you have Ejs installed by right-clicking within the plot and selecting Open Ejs Model from the pop-up menu item. Ejs Hard Sphere Gas model was created using the Easy Java Simulations (Ejs) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_newton_HardShpereGas.jar file will run the program if Java is installed. Ejs is a part of the Open Source Physics Project and is designed to make it easier to access, modify, and generate computer models. Additional Ejs models for statistical mechanics are available. They can be found by searching ComPADRE for Open Source Physics, OSP, or Ejs.

Christian, Wolfgang

2008-07-06

376

Hardness vs Randomness  

Microsoft Academic Search

We present a simple ne wc onstruction of a pseudorandom bit generator ,b ased on the constant depth generators of (N). It stretches a short string of truly random bits into a long string that looks random to an ya lgorithm from a comple xity class C (eg P, NC, PSPACE, ... )u sing an arbitrary function that is hard

Noam Nisan; Avi Wigderson

1994-01-01

377

Work Hard. Be Nice  

ERIC Educational Resources Information Center

In 1994, fresh from a two-year stint with Teach for America, Mike Feinberg and Dave Levin inaugurated the Knowledge Is Power Program (KIPP) in Houston with an enrollment of 49 5th graders. By this Fall, 75 KIPP schools will be up and running, setting children from poor and minority families on a path to college through a combination of hard work,

Mathews, Jay

2009-01-01

378

Hard Times Hit Schools  

ERIC Educational Resources Information Center

Hard-to-grasp dollar amounts are forcing real cuts in K-12 education at a time when the cost of fueling buses and providing school lunches is increasing and the demands of the federal No Child Left Behind Act still loom larger over states and districts. "One of the real challenges is to continue progress in light of the economy," said Gale Gaines,

McNeil, Michele

2008-01-01

379

Piezoelectric coefficients by molecular dynamics simulations in the constant stress ensemble: A case study of quartz  

E-print Network

Piezoelectric coefficients by molecular dynamics simulations in the constant stress ensemble Abstract Piezoelectric (strain) coefficients dij of quartz are calculated in terms of molecular dynamics is employed suppressing significantly stochastic fluctuations of the estimators for piezoelectric coefficients

Mueser, Martin

380

Fundamental formulations and recent achievements in piezoelectric nano-structures: a review.  

PubMed

Piezoelectric nano-structures have been regarded as the next-generation piezoelectric material due to their inherent nano-sized piezoelectricity. This review summarizes the recent theoretical and experimental findings in piezoelectric nano-structures, including piezoelectric nanowires, nanoplates, nanobeams, nanofilms, nanoparticles, and piezoelectric heterogeneous materials containing piezoelectric nano-inhomogeneities. To begin, the types of piezoelectric nano-structured materials and the wide application of piezoelectric nano-structures in recent years are delineated. Next, the theoretical foundations including the definition of surface stress and electric displacement, the surface constitutive relations, the surface equilibrium equations, and nonlocal piezoelectricity, and their applications, are illustrated. Then, the effective mechanical and piezoelectric properties are depicted. Furthermore, the experimental investigations are classified, and some important observations are discussed. Finally, the perspectives and challenges for the future development of piezoelectric nano-structures are pointed out. PMID:23348525

Fang, Xue-Qian; Liu, Jin-Xi; Gupta, Vijay

2013-03-01

381

Piezoelectric effects and electromechanical theories at the nanoscale.  

PubMed

Considerable effort has been made to study the piezoelectric effect on the nanoscale, which serves as a physical basis for a wide range of smart nanodevices and nanoelectronics. This paper reviews recent progress in the research on the piezoelectric properties and electromechanical effects of piezoelectric nanomaterials (PNs). The review begins with an introduction to existing PNs which exhibit a diverse range of atomic structures and configurations. The nanoscale measurement of their effective piezoelectric coefficients (EPCs) is summarised with an emphasis on the major factors determining the piezoelectric properties of PNs. The paper concludes with a review of the electromechanical theories that are able to capture the small-scale effects on PNs, which include the surface piezoelectricity, flexoelectricity and Eringen's nonlocal theory. In contrast to the classical theories, two types of EPCs are defined, which were found to be size-dependent and loading condition-selective. PMID:25315991

Zhang, Jin; Wang, Chengyuan; Bowen, Chris

2014-10-24

382

Nonlinear kinematics for piezoelectricity in ALEGRA-EMMA.  

SciTech Connect

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

Mitchell, John Anthony; Fuller, Timothy Jesse

2013-09-01

383

Flutter control of a composite plate with piezoelectric multilayered actuators  

Microsoft Academic Search

Active flutter velocity enhancement scheme is presented for lifting surfaces, employing Linear Quadratic Gaussian based multi-input multi-output controller with multilayered piezoelectric actuators. To numerically test the developed concept, a composite plate wing, surface bonded with eight piezoelectric bender actuators and sensors has been considered. A modal flutter control model is formulated in state-space domain using coupled piezoelectric finite element procedures

S. Raja; A. A. Pashilkar; R. Sreedeep; J. V. Kamesh

2006-01-01

384

Simulation Study on Material Property of Cantilever Piezoelectric Vibration Generator  

E-print Network

Abstract: For increasing generating capacity of cantilever piezoelectric vibration generator with limited volume, relation between output voltage, inherent frequency and material parameter of unimorph, bimorph in series type and bimorph in parallel type piezoelectric vibration generator is analyzed respectively by mechanical model and finite element modeling. The results indicate PZT-4, PZT-5A and PZT-5H piezoelectric materials and stainless steel, nickel alloy substrate material should be firstly chosen. Copyright 2014 IFSA Publishing, S. L.

unknown authors

2014-01-01

385

Finite element modeling of piezoelectric energy harvesters  

NASA Astrophysics Data System (ADS)

This article reports a novel finite element model of piezoelectric energy harvesters accounting for the effect of nonlinear interface circuits. The idea is to replace the energy harvesting circuit in parallel with the parasitic piezoelectric capacitance by an equivalent load impedance. This approach offers many advantages. First, the model itself can be implemented conveniently in commercial finite element softwares. Second, it directly provides system-level designs on the whole without resorting to circuit solvers. Third, the extensions to complicated structures such as array configurations are straightforward. The proposed finite element model is validated by considering the case of an array system endowed with the standard, parallel-/series-SSHI (synchronized switch harvesting on inductor) interfaces. Good agreement is found between simulation results and analytic estimates.

Wu, P. H.; Shu, Y. C.

2014-03-01

386

Piezoelectric accelerometers for ultrahigh temperature application  

SciTech Connect

High temperature sensors are of major importance to aerospace and energy related industries. In this letter, a high temperature monolithic compression-mode piezoelectric accelerometer was fabricated using YCa{sub 4}O(BO{sub 3}){sub 3} (YCOB) single crystals. The performance of the sensor was tested as function of temperature up to 1000 deg. C and over a frequency range of 100-600 Hz. The accelerometer prototype was found to possess sensitivity of 2.4+-0.4 pC/g, across the measured temperature and frequency range, indicating a low temperature coefficient. Furthermore, the sensor exhibited good stability over an extended dwell time at 900 deg. C, demonstrating that YCOB piezoelectric accelerometers are promising candidates for high temperature sensing applications.

Zhang Shujun; Moses, Paul; Shrout, Thomas R. [Materials Research Institute, Pennsylvania State University, University Park, Pennsylvania 16802 (United States); Jiang Xiaoning [TRS Technologies Inc., 2820 East College Ave., State College, Pennsylvania 16801 (United States); Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States); Lapsley, Michael [TRS Technologies Inc., 2820 East College Ave., State College, Pennsylvania 16801 (United States); Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, Pennsylvania 16802 (United States)

2010-01-04

387

Piezoelectric film load cell robot collision detector  

DOEpatents

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

Lembke, J.R.

1988-03-15

388

Piezoelectric film load cell robot collision detector  

DOEpatents

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

Lembke, J.R.

1989-04-18

389

Piezoelectric film load cell robot collision detector  

DOEpatents

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

Lembke, John R. (Overland Park, KS)

1989-04-18

390

Torque for an Inertial Piezoelectric Rotary Motor  

PubMed Central

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

Xing, Jichun

2013-01-01

391

Cantilevered probe detector with piezoelectric element  

DOEpatents

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

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

2013-04-30

392

Cantilevered probe detector with piezoelectric element  

DOEpatents

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

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

2012-07-10

393

Hard Copy Market Overview  

NASA Astrophysics Data System (ADS)

A number of Color Hard Copy (CHC) market drivers are currently indicating strong growth in the use of CHC technologies for the business graphics marketplace. These market drivers relate to product, software, color monitors and color copiers. The use of color in business graphics allows more information to be relayed than is normally the case in a monochrome format. The communicative powers of full-color computer generated output in the business graphics application area will continue to induce end users to desire and require color in their future applications. A number of color hard copy technologies will be utilized in the presentation graphics arena. Thermal transfer, ink jet, photographic and electrophotographic technologies are all expected to be utilized in the business graphics presentation application area in the future. Since the end of 1984, the availability of color application software packages has grown significantly. Sales revenue generated by business graphics software is expected to grow at a compound annual growth rate of just over 40 percent to 1990. Increased availability of packages to allow the integration of text and graphics is expected. Currently, the latest versions of page description languages such as Postscript, Interpress and DDL all support color output. The use of color monitors will also drive the demand for color hard copy in the business graphics market place. The availability of higher resolution screens is allowing color monitors to be easily used for both text and graphics applications in the office environment. During 1987, the sales of color monitors are expected to surpass the sales of monochrome monitors. Another major color hard copy market driver will be the color copier. In order to take advantage of the communications power of computer generated color output, multiple copies are required for distribution. Product introductions of a new generation of color copiers is now underway with additional introductions expected during 1987. The color hard copy market continues to be in a state of constant change, typical of any immature market. However, much of the change is positive. During 1985, the color hard copy market generated 1.2 billion. By 1990, total market revenue is expected to exceed 5.5 billion. The business graphics CHC application area is expected to grow at a compound annual growth rate greater than 40 percent to 1990.

Testan, Peter R.

1987-04-01

394

Observation of magnetoelectric coupling and local piezoresponse in modified (Na0.5Bi0.5)TiO3-BaTiO3-CoFe2O4 lead-free composites.  

PubMed

Lead-free particulate multiferroic composites of [0.94(Na0.5Bi0.5)TiO3-0.06 BaTiO3]:(Co0.6Zn0.4)(Fe1.7Mn0.3)O4 were synthesized and magnetoelectric (ME) properties were studied. X-ray diffraction and microstructural studies indicated the formation of a two-phase composite system without any impurities. The shift of Raman modes corresponding to ferroelectric and ferrite phases was assigned to the induced strain amid the formation of a two-phase system, in relation to the fraction of each phase in the samples. A strong local piezoresponse and hysteresis loops observed for composites established the ferroelectric properties at a nanoscale. Magnetostriction measurements revealed values of ?11 = -10.4 and ?12 = 5.3 ppm and piezomagnetic coefficient d?11/dH = -0.0087 ppm Oe(-1) at 0.45 kOe for a composite with a ferrite concentration of 35 mol%. A maximum change of 18.5% in magnetization after electrical poling indicates a strong magnetoelectric response of the present composites followed by a direct ME coefficient of 8.2 mV cm(-1) Oe(-1). Our studies point to the fact that the present multiferroic composites having strong ME coupling are useful for lead-free electronic applications. PMID:24849499

Ramana, E Venkata; Figueiras, F; Graa, M P F; Valente, M A

2014-07-14

395

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

396

Multi-scale Modeling for Piezoelectric Composite Materials  

E-print Network

In this paper, we focus on multi-scale modeling and simulation of piezoelectric composite materials. A multi-scale model for piezoelectric composite materials under the framework of Heterogeneous Multi-scale Method(HMM) is proposed. For materials with periodic microstructure, macroscopic model is derived from microscopic model of piezoelectric composite material by asymptotic expansion. Convergence analysis under the framework of homogenization theory is carried out. Moreover, error estimate between HMM solutions and homogenization solutions is derived. A 3-D numerical example of 1-3 type piezoelectric composite materials is employed to verify the error estimate.

Qian Zhang; Xingye Yue

2014-02-02

397

Piezoelectric biosensor with a ladder polymer substrate coating  

DOEpatents

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

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

1998-09-29

398

Frequency modulation drive for a piezoelectric motor  

SciTech Connect

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

Mittas, Anthony (Albuquerque, NM)

2001-01-01

399

New developments concerning piezoelectric materials with defects  

Microsoft Academic Search

The problem of a piezoelectric body with an elliptic cavity is revisited within the frame-work of two-dimensional electro-elasticity. In contrast to our previous formulation, the present analysis is based on the use of exact electric boundary conditions at the rim of the hole, thus avoiding the common assumption of electric impermeability. Expressions for the elastic and electric variables induced inside

Horacio Sosa; Naum Khutoryansky

1996-01-01

400

Piezoelectric cantilevers energy harvesting in MEMS technique  

NASA Astrophysics Data System (ADS)

Piezoelectric cantilevers energy harvesting made by micro-electromechanical system (MEMS) technology can scavenge power from low-level ambient vibration sources. The developed cantilevers energy harvesting are featured with resonate frequency and power output in microwatt level, which is sufficient to the self-supportive sensors for in-service integrity monitoring of large social and environmental infrastructures at remote locations. In this paper, piezoelectric energy harvesting based on thick-film piezoelectric cantilevers is investigated to resonate at specific frequencies of an external vibration energy source, which creating electrical energy via the piezoelectric effect. Our cantilever device has a multiple structure with a proof mass added to the end. The thick film lead zirconate titanate Pb(Zr,Ti)O3 (PZT) coated on the top of Au/Cr/SiO2/Si substrates by sol-gel-spin method. The thickness of the PZT membrane was up to 2?m and the cantilevers substrates thickness 50?m, wideness 1.5mm, length 4mm. The Au/Ti top electrode is patterned on top of the sol-gel-spin coated PZT thick film in order to employ the d31 mode. The prototype energy generator has a measured performance of 0.74?W effective electrical power, and 4.93 DC output voltages to resistance load. The effect of proof mass, beam shape and damping on the power generating performance are modeled to provide a design guideline for maximum power harvesting from environmentally available low frequency vibrations. A multiple structure cantilever is designed to achieve compactness, low resonant frequency and minimum damping coefficient, simultaneously. This device is promising to support networks of ultra-low-power sensor.

Shang, Yingqi; Qiu, Chengjun; Liu, Hongmei; Chen, Xiaojie; Qu, Wei; Dou, Yanwei

2012-04-01

401

Piezoelectric cantilevers energy harvesting in MEMS technique  

NASA Astrophysics Data System (ADS)

Piezoelectric cantilevers energy harvesting made by micro-electromechanical system (MEMS) technology can scavenge power from low-level ambient vibration sources. The developed cantilevers energy harvesting are featured with resonate frequency and power output in microwatt level, which is sufficient to the self-supportive sensors for in-service integrity monitoring of large social and environmental infrastructures at remote locations. In this paper, piezoelectric energy harvesting based on thick-film piezoelectric cantilevers is investigated to resonate at specific frequencies of an external vibration energy source, which creating electrical energy via the piezoelectric effect. Our cantilever device has a multiple structure with a proof mass added to the end. The thick film lead zirconate titanate Pb(Zr,Ti)O3 (PZT) coated on the top of Au/Cr/SiO2/Si substrates by sol-gel-spin method. The thickness of the PZT membrane was up to 2?m and the cantilevers substrates thickness 50?m, wideness 1.5mm, length 4mm. The Au/Ti top electrode is patterned on top of the sol-gel-spin coated PZT thick film in order to employ the d31 mode. The prototype energy generator has a measured performance of 0.74?W effective electrical power, and 4.93 DC output voltages to resistance load. The effect of proof mass, beam shape and damping on the power generating performance are modeled to provide a design guideline for maximum power harvesting from environmentally available low frequency vibrations. A multiple structure cantilever is designed to achieve compactness, low resonant frequency and minimum damping coefficient, simultaneously. This device is promising to support networks of ultra-low-power sensor.

Shang, Yingqi; Qiu, Chengjun; Liu, Hongmei; Chen, Xiaojie; Qu, Wei; Dou, Yanwei

2011-11-01

402

Piezoelectric cantilever microphone for photoacoustic gas detector  

Microsoft Academic Search

New micromachined pressure sensors based on PZT coated silicon cantilevers have been fabricated and integrated in a photoacoustic gas detector. PZT Sol-gel thin films texture and composition were optimized with respect to the transverse piezoelectric coefficient e31,f. A best value of -12 C\\/m was obtained with (100)\\/(001) textured thin films at the MPB composition. Optimum stress compensation between the different

Nicolas Ledermann; Jacek Baborowski; Andreas Seifert; Bert Willing; Stephane Hiboux; Paul Muralt; Nava Setter; Martin Forster

2001-01-01

403

Piezoelectric films using hybrid technology for ultrasonic array and electronic device applications.  

E-print Network

??Lead zirconate titanate (PZT) films are promising for MEMS type micro-devices applications because of their high electromechanical coupling coefficients and excellent piezoelectric properties. PZT piezoelectric (more)

Chao, Chen.

2008-01-01

404

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

405

Actuation characteristics and applications of piezoelectric materials and ionic polymer-metal composites.  

E-print Network

??This thesis focuses on the actuation characteristics of piezoelectric materials and ionic polymer-metal composites (IPMCs) for biomedical applications. The piezoelectric actuated plates and shells on (more)

Zhang, Lei.

2008-01-01

406

Report on the piezoelectric frequency effect in quartz and its possibility in other piezoelectric materials  

E-print Network

We report the eigen-frequency shift induced by an applied voltage on quartz material. The samples are in the form of commercial 32 KHz quartz tuning forks used in watches. Three vibration modes are studied: one prong oscillates, two prongs oscillate in the same and opposite directions. They all show a parabolic dependence of the eigen-frequency shift on the bias voltage applied across the fork, which is explained owing to the voltage-induced internal stress that varies as the fork oscillates. Thus, this piezoelectric frequency effect is possible to exist in all piezoelectric materials. The average coefficient of the piezoelectric frequency effect is as low as several hundred nano-Hz per millivolt, implying that the most precise (nano-Hz) yet fast-response voltage-controlled oscillators and phase-locked loops can be built.

Hou, Yubin

2012-01-01

407

Energy harvesting with piezoelectric applied on shoes  

NASA Astrophysics Data System (ADS)

In the last few years the continuous demand of energy saving has brought continuous research on low-power devices, energy storage and new sources of energy. Energy harvesting is an interesting solution that captures the energy from the environment that would otherwise be wasted. This work presents an electric-mechanical model of a piezoelectric transducer in a cantilever configuration. The model has been characterized measuring the acceleration and the open circuit voltage of a piezoelectric cantilever subjected to a sinusoidal force with different values frequency and subject to an impulsive force. The model has been used to identify the optimal position in which the piezoelectric cantilever has to be placed on a shoe in order to obtain the maximum energy while walking or running. As a second step we designed the DC-DC converter with an hysteresis comparator. The circuit is able to give energy to switch on a microprocessor for the amount of time long enough to capture and store the information required. The complete system has been implemented, installed on a shoe and used in a 10 Km running competition.

Camilloni, Enrico; Carloni, Mirko; Giammarini, Marco; Conti, Massimo

2013-05-01

408

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

409

Optimization of a piezoelectric acoustical compressor  

NASA Astrophysics Data System (ADS)

A one-dimensional, axisymmetric, linear finite element model describing a fluid interacting with a piezoelectric actuator is developed. This system is used to generate finite amplitude standing waves in an acoustic cavity with rigid walls. The model includes the effects of viscous and thermal damping of the fluid at the boundary of the cavity, and material damping in the piezoelectric actuator. Two types of piezoelectric actuators are considered, a stacked layer actuator, and a bending bimorph actuator. The resulting finite element equations are used to determine the optimum shape for the acoustic cavity that results in the highest pressure for the least input power. Optimal chambers were found that could generate 19 psi at 1700 Hz for 50 watts of power using air as a working fluid and 70 psi at 950 Hz for 42 watts of power using R-134A as a working fluid. The optimization results were verified against the commercial finite element code ANSYS and published experimental data. The potential of the transition of the developed technology to other fields is viable and is only limited by our imagination as it includes numerous applications such as the inflation of inflatable structures, inflation of tires and refrigeration and air-conditioning.

Dickens, R. A.; Baz, A.

2005-05-01

410

Modeling of functionally graded piezoelectric ultrasonic transducers.  

PubMed

The application of functionally graded material (FGM) concept to piezoelectric transducers allows the design of composite transducers without interfaces, due to the continuous change of property values. Thus, large improvements can be achieved, as reduction of stress concentration, increasing of bonding strength, and bandwidth. This work proposes to design and to model FGM piezoelectric transducers and to compare their performance with non-FGM ones. Analytical and finite element (FE) modeling of FGM piezoelectric transducers radiating a plane pressure wave in fluid medium are developed and their results are compared. The ANSYS software is used for the FE modeling. The analytical model is based on FGM-equivalent acoustic transmission-line model, which is implemented using MATLAB software. Two cases are considered: (i) the transducer emits a pressure wave in water and it is composed of a graded piezoceramic disk, and backing and matching layers made of homogeneous materials; (ii) the transducer has no backing and matching layer; in this case, no external load is simulated. Time and frequency pressure responses are obtained through a transient analysis. The material properties are graded along thickness direction. Linear and exponential gradation functions are implemented to illustrate the influence of gradation on the transducer pressure response, electrical impedance, and resonance frequencies. PMID:19230947

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

2009-05-01

411

Plucked piezoelectric bimorphs for energy harvesting applications  

NASA Astrophysics Data System (ADS)

The modern drive towards mobility and wireless devices is motivating intense research in energy harvesting (EH) technologies. In an effort to reduce the battery burden of people, we are investigating a novel piezoelectric wearable energy harvester. As piezoelectric EH is significantly more effective at high frequencies, in opposition to the characteristically low-frequency human activities, we propose the use of an up-conversion strategy analogous to the pizzicato musical technique. In order to guide the design of such harvester, we have modelled with Finite Elements (FE) the response and power generation of a piezoelectric bimorph while it is "plucked", i.e. deflected, then released and permitted to vibrate freely. An experimental rig has been devised and set up to reproduce the action of the bimorph in the harvester. Measurements of the voltage output and the energy dissipated across a series resistor are reported and compared with the FE predictions. As the novel harvester will feature a number of bimorphs, each plucked tens of times per step, we predict a total power output of several mW, with imperceptible effect on the wearer's gait.

Pozzi, Michele; Zhu, Meiling

2011-06-01

412

Hybrid Piezoelectric/Fiber-Optic Sensor Sheets  

NASA Technical Reports Server (NTRS)

Hybrid piezoelectric/fiber-optic (HyPFO) sensor sheets are undergoing development. They are intended for use in nondestructive evaluation and long-term monitoring of the integrity of diverse structures, including aerospace, aeronautical, automotive, and large stationary ones. It is anticipated that the further development and subsequent commercialization of the HyPFO sensor systems will lead to economic benefits in the form of increased safety, reduction of life-cycle costs through real-time structural monitoring, increased structural reliability, reduction of maintenance costs, and increased readiness for service. The concept of a HyPFO sensor sheet is a generalization of the concept of a SMART Layer(TradeMark), which is a patented device that comprises a thin dielectric film containing an embedded network of distributed piezoelectric actuator/sensors. Such a device can be mounted on the surface of a metallic structure or embedded inside a composite-material structure during fabrication of the structure. There is has been substantial interest in incorporating sensors other than piezoelectric ones into SMART Layer(TradeMark) networks: in particular, because of the popularity of the use of fiber-optic sensors for monitoring the "health" of structures in recent years, it was decided to incorporate fiber-optic sensors, giving rise to the concept of HyPFO devices.

Lin, Mark; Qing, Xinlin

2004-01-01

413

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

414

A piezoelectric actuator-driven loading device for mechanical condition during bone tissue engineering  

NASA Astrophysics Data System (ADS)

Bone cells live in an environment heavily influenced by mechanical forces. The researches of bone cell responses in hard scaffolds under differently mechanical conditions will be greatly beneficial to elucidating the mechanisms of bone mechanotransduction as well as applications of mechanical condition in bone tissue engineering. However, the appropriate device for the experiments is prerequisite. A loading device suitable to hard scaffold for study on mechanical responses of bone cells was made by usage of a kind of long-travel, high-load piezoelectric actuator. The device, which is so small enough to work in a standard incubator, can cause hard scaffolds with directly uniaxial compressive strains with more magnitudes, frequency components, and waveforms, including bone physiologically mechanical state, precisely controlled by a computer. The device achieves precise mechanical conditions by testing verification. The device may produce a model that will be suitable for investigating the influences of mechanical responses on bone cells in 3D hard scaffolds in vitro matching that in cancellous bone in vivo and may be applied during bone tissue engineering culture.

Zhang, C. Q.; Wu, H.; Dong, X.

2008-10-01

415

Hardness of Materials- Introduction  

NSDL National Science Digital Library

This lesson plan from Edmonds Community College will serve as an excellent introduction to the hardness of materials. The module illustrates the differences in properties between different materials. Students will determine property differences between different types of materials, observe property differences between materials of the same class, measure, record and report their results and observe differences in results due to operator error. Student, instructor and course evaluation questions are included. This document will serve as a framework for instructors and may be downloaded in PDF format.

2012-10-12

416

Hard metal composition  

DOEpatents

A composition of matter having a Rockwell A hardness of at least 85 is formed from a precursor mixture comprising between 3 and 10 wt % boron carbide and the remainder a metal mixture comprising from 70 to 90% tungsten or molybdenum, with the remainder of the metal mixture comprising nickel and iron or a mixture thereof. The composition has a relatively low density of between 7 and 14 g/cc. The precursor is preferably hot pressed to yield a composition having greater than 100% of theoretical density.

Sheinberg, H.

1983-07-26

417

Hard physics in PHENIX  

E-print Network

We review recent results on hard observables in p+p, d+A and A+A collisions obtained by the PHENIX experiment. Emphasis is put on those measurements that provide insight into the properties of hot QCD media expected to be created in nucleus-nucleus collisions at RHIC energies. Direct photon spectra, jet properties and heavy quarks production measured in p+p and d+Au collisions are compared to the same observables extracted in heavy ion collisions to find modifications due to the presence of hot QCD matter.

D. Peressounko; for the PHENIX collaboration

2005-12-08

418

Power enhancement of piezoelectric transformers by adding heat transfer equipment.  

PubMed

It is known that piezoelectric transformers have several inherent advantages compared with conventional electromagnetic transformers. However, the maximum power capacity of piezoelectric transformers is not as large as electromagnetic transformers in practice, especially in the case of high output current. The theoretical power density of piezoelectric transformers calculated by stress boundary can reach 330 W/cm(3), but no piezoelectric transformer has ever reached such a high power density in practice. The power density of piezoelectric transformers is limited to 33 W/cm(3) in practical applications. The underlying reason is that the maximum passing current of the piezoelectric material (mechanical current) is limited by the temperature rise caused by heat generation. To increase this current and the power capacity, we proposed to add a thermal pad to the piezoelectric transformer to dissipate heat. The experimental results showed that the proposed techniques can increase by 3 times the output current of the piezoelectric transformer. A theoretical-phenomenological model which explains the relationship between vibration velocity and generated heat is also established to verify the experimental results. PMID:23143563

Su, Yu-Hao; Liu, Yuan-Ping; Vasic, Dejan; Wu, Wen-Jong; Costa, Franois; Lee, Chih-Kung

2012-10-01

419

Analysis of piezoelectric bimorphs and plates with segmented actuators  

Microsoft Academic Search

Elastic plates with distributed or segmented piezoelectric layers have been analyzed using the classical laminated plate theory, the first-order shear deformation theory, and the results are compared with an analytical solution. The plate theories and the analytical solution take into account both the direct and the converse piezoelectric effects, and assume generalized plane strain deformations. The transverse displacements from both

Senthil S. Vel; R. C. Batra

2001-01-01

420

Linear electro-elastic fracture mechanics of piezoelectric materials  

Microsoft Academic Search

The concepts of linear elastic fracture mechanics, generalized to treat piezoelectric effects, are employed to study the influence of the electrical fields on the fracture behavior of piezoelectric materials. The method of distributed dislocations and electric dipoles, already existing in the literature, is used to calculate the electro-elastic fields and the energy-release rate for a finite crack embedded in an

Y. E. Pak

1992-01-01

421

Multifunctional devices combining shape-memory alloy and piezoelectric materials  

NASA Astrophysics Data System (ADS)

We succeeded in the deposition of piezoelectric thin film on a titanium substrate and on nickel-titanium alloy (shapememory alloy) by employing the hydrothermal synthesis method for the direct deposition of PZT thin film, which is a piezoelectric material, on a titanium substrate. The formed film is quite thin (tens of micrometers), and the density is low (theoretical density of ~70%). As the thin piezoelectric film is formed by the layering of many crystals, it is capable of responding to large deformations (up to 5%), which would have been inconceivable with the existing piezoelectric materials without any structural damages. The hydrothermal synthesis method was used in this research study to form films of PZT piezoelectric films on the surfaces of nickel-titanium shape-memory alloy wires to fabricate and evaluate a new multifunctional device that features a combination of four effects, namely, the shape-memory effect, super-elasticity effect, piezoelectric effect, and pyroelectric effect. The fabricated fiber was subjected to a tensile test in the super-elastic state, and the amount of deformation thereof was read from the piezoelectric effect to show the functioning of both the super-elastic effect and the piezoelectric effect.

Sato, Hiroshi

2014-03-01

422

Gap Wave Propagation in Functionally Graded Piezoelectric Material Structures  

E-print Network

Gap Wave Propagation in Functionally Graded Piezoelectric Material Structures Jianke Du, Kai Xian@nbu.edu.cn Abstract-Shear horizontal gap wave propagating between functionally graded piezoelectric material (FGPM-space and a piezoceramic plate were investigated in [3]. A new-style material called functionally graded material (FGM

Wang, Ji

423

Love wave propagation in functionally graded piezoelectric material layer  

E-print Network

Love wave propagation in functionally graded piezoelectric material layer Jianke Du *, Xiaoying Jin is used to investigate Love waves in functionally graded piezoelectric material (FGPM) layer bonded functionally graded material (FGM) was proposed to solve problems in the thermal- protection systems

Wang, Ji

424

Finite element modeling of piezoelectric sensors and actuators  

Microsoft Academic Search

A finite element formulation for vibration control of a laminated plate with piezoelectric sensors\\/actuators is presented. Classical laminate theory with the induced strain actuation and Hamilton's principle are used to formulate the equations of motion. The total charge developed on the sensor layer is calculated from the direct piezoelectric equation. The equations of motion and the total charge are discretized

Woo-Seok Hwang; Hyun C. Park

1993-01-01

425

The Design of Efficient Broad-Band Piezoelectric Transducers  

Microsoft Academic Search

Absrruct-A design method for acoustic thin disk transducers with high efficiency, broad bandwidth, and good impulse response is presented. This method is based on the use of quarter-wave matching layers between the piezoelectric material and the acoustic load. As is made evident using the transmission line model of Krimholtz, Leedom, and Matthaei, the finite thickness of the piezoelectric material must

C. S. Desilets; J. D. Fraser; G. S. Kino

1978-01-01

426

Modelling of Piezoelectric Actuator Dynamics for Active Structural Control  

Microsoft Academic Search

The paper models the effects of dynamic coupling between a structure and an electrical network through the piezoelectric effect. The coupled equations of motion of an arbitrary elastic structure with piezoelectric elements and passive electronics are derived. State space models are developed for three important cases: direct voltage driven electrodes, direct charge driven electrodes, and an indirect drive case where

Nesbitt W. Hagood; Walter H. Chung; Andreas Von Flotow

1990-01-01

427

Performance of an active control system with piezoelectric actuators  

Microsoft Academic Search

This study deals with the utilization of piezoelectric actuators in controlling the structural vibrations of flexible beams. A Modified Independent Modal Space Control (MIMSC) method is presented to select the optimal location, control gains and excitation voltage of the piezoelectric actuators. The method minimizes the vibration amplitudes of beams to which these actuators are bonded, as well as the input

A. Baz; S. Poh

1988-01-01

428

RF sputtered piezoelectric zinc oxide thin film for transducer applications  

E-print Network

on the piezoelectric and crystalline qualities of the ZnO thin films. Experimental results showed that the multilayer, and bulk acoustic wave (BAW) devices [1]. A strategic advantage of deposited ZnO thin film on the quality of the piezoelectric ZnO thin films. Substantial research efforts have been devoted to the studies

Tang, William C

429

Slipping Detection with Integrated Piezoelectric Vibration Tactile Sensors  

Microsoft Academic Search

This paper presents the detection of slipping with integrated piezoelectric vibration tactile sensors. A tactile sensor is important for robotics to find a mechanical pressure and contact condition between grippers and objects. We have proposed the integrated piezoelectric vibration-type tactile sensors to realize a high sensitivity and a wide measurement range. Previous sensors were only applied to measure the pressure

S. Kosaka; M. Nakajima; T. Fukuda; H. Matsuura

2008-01-01

430

Characterization of piezoelectric film sensors for tongue-computer interface  

Microsoft Academic Search

In this paper we examine the pressure detection quality and signal clarity for two types of piezoelectric film sen- sors. One sensor was coated with polydimethylsiloxane (PDMS) while the other remained uncoated. Our goal was to determine how coating the sensor with PDMS would affect sensor per- formance. Our long-term goal is to develop a tongue-computer interface using piezoelectric film

Lukash Monczak; Daniel Shapiro; Alexey Borisenko; Ovidiu Draghici; Miodrag Bolic

2011-01-01

431

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

432

Development of energy harvesting device using piezoelectric material  

Microsoft Academic Search

Using piezoelectric elements to harvest energy from ambient vibration and human motion has been of great interest recently. This study quantifies the amount of energy generated by piezoelectric device from vibration environment and human motion. Nickel metal hydride rechargeable battery has been used to store the energy generated. Throughout the experiment, the discharged 40mAh rechargeable battery can be charged to

Robiah Ahmad; Mohd Hanifah Hashim

2011-01-01

433

Bending Analysis in AlN-Based Multilayered Piezoelectric Cantilevers  

Microsoft Academic Search

This paper focuses on the design and fabrication of piezoelectric cantilevers and on the analysis of their bending, due to residual stress, as a function of growth parameters and geometrical features. The multilayered cantilevers consist of two top and bottom Molybdenum metals and an Aluminium nitride piezoelectric layer deposited onto a Polysilicon elastic layer using DC magnetron sputtering. After having

C. Giordano; I. Ingrosso; M. Grande; A. Qualtieri; M. Pugliese; M. T. Todaro; V. Tasco; M. De Vittorio; A. Passaseo

2009-01-01

434

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

435

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

436

Nonlinear piezoelectricity in epitaxial ferroelectrics at high electric fields  

SciTech Connect

Non-linear effects in the coupling of polarization with elastic strain have been predicted to occur in ferroelectric materials subjected to high electric fields. Such predictions are tested here for a Pb(Zr0.2,Ti0.8)O3 ferroelectric thin film at electric fields in the range of several MV/cm. Thermal runaway and subsequent low-frequency dielectric breakdown are overcome by using nanosecond electrical pulses to apply high electric fields, which made the probing of the film's structure possible at piezoelectric strains reaching up to 2.7%. The piezoelectric strain exceeds predictions based on constant piezoelectric coefficients at electric fields from 2 to 4 MV/cm, which is consistent with a non-linear effect predicted to occur at concomitant piezoelectric distortions. At higher fields, the piezoelectric response decreases, suggesting that elastic interactions between atoms enter a new regime.

Grigoriev, Alexei [University of Wisconsin, Madison; Sichel, Rebecca [University of Wisconsin, Madison; Lee, Ho Nyung [ORNL; Landahl, Eric C. [Argonne National Laboratory (ANL); Adams, Bernhard [Argonne National Laboratory (ANL); Dufresne, Eric M. [Argonne National Laboratory (ANL); Evans, Paul G. [University of Wisconsin, Madison

2008-01-01

437

A review of non linear piezoelectricity in semiconductors  

NASA Astrophysics Data System (ADS)

The piezoelectric effect in polar semiconductor has seen increased interest in recent years because of the prospect of exploiting semiconducting behavior and piezoelectric response, i.e. generating electric fields in response to pressure, in novel optoelectronic devices with applications as pressure sensors and energy harvesting. In this paper we review the basic concepts and recent findings related to the novel concept of non-linear piezoelectricity, which can be exploited in composite nanostructured materials to increase the piezoelectric response compared to bulk materials. Applications to light emitting diodes and nanowires will also be discussed. We will show how the non-linear theory of piezoelectricity can in some cases lead to opposite predictions compared to the classic linear theory.

Migliorato, M. A.; Pal, J.; Garg, R.; Tse, G.; Al-Zahrani, H. Y. S.; Monteverde, U.; Tomi?, S.; Li, C.-K.; Wu, Y.-R.; Crutchley, B. G.; Marko, I. P.; Sweeney, S. J.

2014-03-01

438

Low-Temperature Solution Processable Electrodes for Piezoelectric Sensors Applications  

NASA Astrophysics Data System (ADS)

Piezoelectric thin-film sensors are suitable for a wide range of applications from physiological measurements to industrial monitoring systems. The use of flexible materials in combination with high-throughput printing technologies enables cost-effective manufacturing of custom-designed, highly integratable piezoelectric sensors. This type of sensor can, for instance, improve industrial process control or enable the embedding of ubiquitous sensors in our living environment to improve quality of life. Here, we discuss the benefits, challenges and potential applications of piezoelectric thin-film sensors. The piezoelectric sensor elements are fabricated by printing electrodes on both sides of unmetallized poly(vinylidene fluoride) film. We show that materials which are solution processable in low temperatures, biocompatible and environmental friendly are suitable for use as electrode materials in piezoelectric sensors.

Tuukkanen, Sampo; Julin, Tuomas; Rantanen, Ville; Zakrzewski, Mari; Moilanen, Pasi; Lupo, Donald

2013-05-01

439

Outer hair cell piezoelectricity: frequency response enhancement and resonance behavior.  

PubMed

Stretching or compressing an outer hair cell alters its membrane potential and, conversely, changing the electrical potential alters its length. This bi-directional energy conversion takes place in the cell's lateral wall and resembles the direct and converse piezoelectric effects both qualitatively and quantitatively. A piezoelectric model of the lateral wall has been developed that is based on the electrical and material parameters of the lateral wall. An equivalent circuit for the outer hair cell that includes piezoelectricity shows a greater admittance at high frequencies than one containing only membrane resistance and capacitance. The model also predicts resonance at ultrasonic frequencies that is inversely proportional to cell length. These features suggest all mammals use outer hair cell piezoelectricity to support the high-frequency receptor potentials that drive electromotility. It is also possible that members of some mammalian orders use outer hair cell piezoelectric resonance in detecting species-specific vocalizations. PMID:14514199

Weitzel, Erik K; Tasker, Ron; Brownell, William E

2003-09-01

440

Reliability of Sn/Pb and lead-free (SnAgCu) solders of surface mounted miniaturized passive components for extreme temperature (-185C to +125C) space missions  

NASA Astrophysics Data System (ADS)

Surface mount electronic package test boards have been assembled using tin/lead (Sn/Pb) and lead-free (Pb-free or SnAgCu or SAC305) solders. The soldered surface mount packages include ball grid arrays (BGA), flat packs, various sizes of passive chip components, etc. They have been optically inspected after assembly and subsequently subjected to extreme temperature thermal cycling to assess their reliability for future deep space, long-term, extreme temperature environmental missions. In this study, the employed temperature range (-185C to +125C) covers military specifications (-55C to +100C), extreme cold Martian (-120C to +115C), asteroid Nereus (-180C to +25C) and JUNO (-150C to +120C) environments. The boards were inspected at room temperature and at various intervals as a function of extreme temperature thermal cycling and bake duration. Electrical resistance measurements made at room temperature are reported and the tests to date have shown some change in resistance as a function of extreme temperature thermal cycling and some showed increase in resistance. However, the change in interconnect resistance becomes more noticeable with increasing number of thermal cycles. Further research work will be carried out to understand the reliability of packages under extreme temperature applications (-185C to +125C) via continuously monitoring the daisy chain resistance for BGA, Flat-packs, lead less chip packages, etc. This paper will describe the experimental reliability results of miniaturized passive components (01005, 0201, 0402, 0603, 0805, and 1206) assembled using surface mounting processes with tin-lead and lead-free solder alloys under extreme temperature environments.

Ramesham, Rajeshuni

2011-02-01

441

Hard Metal Disease  

PubMed Central

In Great Britain there have been no published reports of respiratory disease occurring amongst workers in the hard metal (tungsten carbide) industry. In this paper the clinical and radiological findings in six cases and the pathological findings in one are described. In two cases physiological studies indicated mild alveolar diffusion defects. Histological examination in a fatal case revealed diffuse pulmonary interstitial fibrosis with marked peribronchial and perivascular fibrosis and bronchial epithelial hyperplasia and metaplasia. Radiological surveys revealed the sporadic occurrence and low incidence of the disease. The alterations in respiratory mechanics which occurred in two workers following a day's exposure to dust are described. Airborne dust concentrations are given. The industrial process is outlined and the literature is reviewed. The toxicity of the metals is discussed, and our findings are compared with those reported from Europe and the United States. We are of the opinion that the changes which we would describe as hard metal disease are caused by the inhalation of dust at work and that the component responsible may be cobalt. Images PMID:13970036

Bech, A. O.; Kipling, M. D.; Heather, J. C.

1962-01-01

442

PEEK ADR-2000 with Piezoelectric Sensor The PEEK ADR-2000 unit uses inputs from piezoelectric sensors to conduct vehicle,  

E-print Network

1 PEEK ADR-2000 with Piezoelectric Sensor The PEEK ADR-2000 unit uses inputs from piezoelectric sensors to conduct vehicle, speed, axle weight, classification, length, gross weight counts. The PEEK ADR to recharge unit) Power Requirements The PEEK ADR-2000 comes with an internal, rechargeable battery. It can

Prevedouros, Panos D.

443

PMN-PT PIEZOELECTRIC MATERIAL AND RELATED APPLICATIONS IN SILICON-INTEGRATED DEVICES LIKE MICROACTUATORS AND  

E-print Network

PMN-PT PIEZOELECTRIC MATERIAL AND RELATED APPLICATIONS IN SILICON-INTEGRATED DEVICES LIKE provides the means for approaching towards novel concepts combining silicon technology with piezoelectric PMN-PT piezoelectric material on a Silicon wafer rather than sputtering thin piezoelectric films (a

Boyer, Edmond

444

Topology Optimization Applied to the Design of Functionally Graded Piezoelectric Bimorph  

E-print Network

Topology Optimization Applied to the Design of Functionally Graded Piezoelectric Bimorph Ronny C and increased bonding strength. Recently, this concept has been explored in piezoelectric materials to improve properties and to increase the lifetime of bimorph piezoelectric actuators. Usually, elastic, piezoelectric

Paulino, Glaucio H.

445

A Resonant Damping Study Using Piezoelectric Materials  

NASA Technical Reports Server (NTRS)

Excessive vibration of turbomachinery blades causes high cycle fatigue (HCF) problems requiring damping treatments to mitigate vibration levels. Based on the technical challenges and requirements learned from previous turbomachinery blade research, a feasibility study of resonant damping control using shunted piezoelectric patches with passive and active control techniques has been conducted on cantilever beam specimens. Test results for the passive damping circuit show that the optimum resistive shunt circuit reduces the third bending resonant vibration by almost 50%, and the optimum inductive circuit reduces the vibration by 90%. In a separate test, active control reduced vibration by approximately 98%.

Min, J. B.; Duffy, K. P.; Choi, B. B.; Morrison, C. R.; Jansen, R. H.; Provenza, A. J.

2008-01-01

446

Virus-based piezoelectric energy generator  

SciTech Connect

Lawrence Berkeley National Laboratory scientists have developed a way to generate power using harmless viruses that convert mechanical energy into electricity. The milestone could lead to tiny devices that harvest electrical energy from the vibrations of everyday tasks. The first part of the video shows how Berkeley Lab scientists harness the piezoelectric properties of the virus to convert the force of a finger tap into electricity. The second part reveals the "viral-electric" generators in action, first by pressing only one of the generators, then by pressing two at the same time, which produces more current.

None

2012-01-01

447

Temperature driven nano-domain evolution in lead-free Ba(Zr0.2Ti0.8)O3-50(Ba0.7Ca0.3)TiO3 piezoceramics  

NASA Astrophysics Data System (ADS)

Hierarchical micro- and nanoscale domain structures in Pb-free Ba(Zr0.2Ti0.8)O3-50(Ba0.7Ca0.3)TiO3 piezoceramics were investigated by transmission electron microscopy. In situ heating and cooling studies of domain structure evolution reveal an irreversible domain transformation from a wedge-shaped rhombohedral nanodomain structure to a lamellar tetragonal domain structure, which could be associated with strong piezoelectricity in Ba(Zr0.2Ti0.8)O3-50(Ba0.7Ca0.3)TiO3 piezoceramics.

Lu, Shengbo; Xu, Zhengkui; Su, Shi; Zuo, Ruzhong

2014-07-01

448

Lead-free Solders in Microelectronics  

Microsoft Academic Search

Practically all microelectronic assemblies in use today utilize PbSn solders for interconnection. With the advent of chip scale packaging technologies, the usage of solder connections has increased. The most widely used PbSn solder has the eutectic composition. Emerging environmental regulations worldwide, most notably in Europe and Japan, have targeted the elimination of Pb usage in electronic assemblies, due to the

Mulugeta Abtew; Guna Selvaduray

2000-01-01

449

Lead Free Packaging and Sn-Whiskers  

Microsoft Academic Search

Replacement of Pb\\/Sn terminations on electronic devices with pure Sn has proven to be much more difficult than expected. The main problem is Sn whisker formation. Sn whiskers are single crystal, mechanically strong, metallic filaments that can nucleate and grow over time in such a way as to lead to device failure in the field. In this study we present

J. W. Osenbach; P. Ruengsinsub

450

Exciting Hard Spheres  

E-print Network

We investigate the collision cascade that is generated by a single moving incident particle on a static hard-sphere gas. We argue that the number of moving particles at time t grows as t^{xi} and the number collisions up to time t grows as t^{eta}, with xi=2d/(d+2) and eta=2(d+1)/(d+2) and d the spatial dimension. These growth laws are the same as those from a hydrodynamic theory for the shock wave emanating from an explosion. Our predictions are verified by molecular dynamics simulations in d=1 and 2. For a particle incident on a static gas in a half-space, the resulting backsplatter ultimately contains almost all the initial energy.

T. Antal; P. L. Krapivsky; S. Redner

2008-05-25

451

Integrated piezoelectric actuators in deep drawing tools  

NASA Astrophysics Data System (ADS)

The production of car body panels are defective in succession of process fluctuations. Thus the produced car body panel can be precise or damaged. To reduce the error rate, an intelligent deep drawing tool was developed at the Fraunhofer Institute for Machine Tools and Forming Technology IWU in cooperation with Audi and Volkswagen. Mechatronic components in a closed-loop control is the main differentiating factor between an intelligent and a conventional deep drawing tool. In correlation with sensors for process monitoring, the intelligent tool consists of piezoelectric actuators to actuate the deep drawing process. By enabling the usage of sensors and actuators at the die, the forming tool transform to a smart structure. The interface between sensors and actuators will be realized with a closed-loop control. The content of this research will present the experimental results with the piezoelectric actuator. For the analysis a production-oriented forming tool with all automotive requirements were used. The disposed actuators are monolithic multilayer actuators of the piezo injector system. In order to achieve required force, the actuators are combined in a cluster. The cluster is redundant and economical. In addition to the detailed assembly structures, this research will highlight intensive analysis with the intelligent deep drawing tool.

Neugebauer, R.; Mainda, P.; Drossel, W.-G.; Kerschner, M.; Wolf, K.

2011-04-01

452

An Implanted, Stimulated Muscle Powered Piezoelectric Generator  

NASA Technical Reports Server (NTRS)

A totally implantable piezoelectric generator system able to harness power from electrically activated muscle could be used to augment the power systems of implanted medical devices, such as neural prostheses, by reducing the number of battery replacement surgeries or by allowing periods of untethered functionality. The features of our generator design are no moving parts and the use of a portion of the generated power for system operation and regulation. A software model of the system has been developed and simulations have been performed to predict the output power as the system parameters were varied within their constraints. Mechanical forces that mimic muscle forces have been experimentally applied to a piezoelectric generator to verify the accuracy of the simulations and to explore losses due to mechanical coupling. Depending on the selection of system parameters, software simulations predict that this generator concept can generate up to approximately 700 W of power, which is greater than the power necessary to drive the generator, conservatively estimated to be 50 W. These results suggest that this concept has the potential to be an implantable, self-replenishing power source and further investigation is underway.

Lewandowski, Beth; Gustafson, Kenneth; Kilgore, Kevin

2007-01-01

453

Flexible piezoelectric energy harvesting from jaw movements  

NASA Astrophysics Data System (ADS)

Piezoelectric fiber composites (PFC) represent an interesting subset of smart materials that can function as sensor, actuator and energy converter. Despite their excellent potential for energy harvesting, very few PFC mechanisms have been developed to capture the human body power and convert it into an electric current to power wearable electronic devices. This paper provides a proof of concept for a head-mounted device with a PFC chin strap capable of harvesting energy from jaw movements. An electromechanical model based on the bond graph method is developed to predict the power output of the energy harvesting system. The optimum resistance value of the load and the best stretch ratio in the strap are also determined. A prototype was developed and tested and its performances were compared to the analytical model predictions. The proposed piezoelectric strap mechanism can be added to all types of head-mounted devices to power small-scale electronic devices such as hearing aids, electronic hearing protectors and communication earpieces.

Delnavaz, Aidin; Voix, Jrmie

2014-10-01

454

Vibration of micromachined circular piezoelectric diaphragms.  

PubMed

Electrically and mechanically excited resonances in micromachined circular piezoelectric diaphragms have been investigated. The diaphragm structures were piezoelectric unimorphs consisting of Pb(Zr0.52,Ti0.48)O3 (PZT) films and thermally grown silicon oxide (SiO2) layers. For electrical excitation, ring-shaped interdigitated (IDT) electrodes formed on the top of the PZT layer were used to induce strain in the diaphragms. The diaphragm structures behaved much like circular membranes in which the membrane tension was approximately 206 N/m, at the fundamental modes. For higher modes, the resonance frequencies deviated from the theoretical values due to the finite stiffness of the diaphragms. Under mechanical drive, both symmetric and asymmetric modes were excited. However, for electrical excitation, the symmetric modes were dominant due to the symmetry of the driving IDT electrodes. At a pressure of 727 Torr, the quality factor was approximately 250, and this rose to 2000 at pressures below 1 Torr. When a forward bias was applied to the diaphragm, the membrane tension decreased, but under reverse biases the tension increased. However, because of repoling under reverse biases greater than the coercive field of the PZT film, the achievable increase in the membrane tension was limited. In the diaphragm structure, the nonlinear vibration was governed by geometric nonlinearity rather than material nonlinearity. In addition, evidence of non-180 degrees domain wall motion of the PZT layer in released diaphragms was observed. PMID:16615573

Hong, Eunki; Trolier-McKinstry, Susan; Smith, Robert; Krishnaswamy, Silai V; Freidhoff, Carl B

2006-04-01

455

Piezoelectric aluminum nitride resonator for oscillator.  

PubMed

This work investigates properties of the thin film elongation acoustic resonator (TFEAR) operating at megahertz frequencies in air. This resonator is composed of a piezoelectric layer of AlN sandwiched between 2 Al electrodes. TFEAR works in the extensional mode excited via AlN d31 piezoelectric coefficient. A 3D finite element method (3D-FEM) analysis using ANSYS software has been performed to model static modal and harmonic behavior of the TFEAR. To consider insertion losses into the substrate, equivalent electrical models based on a modified Butterworth-Van Dyke (MBVD) circuit have been improved by adding extra dissipative elements. Thus, a whole model for the on-wafer characterization setup is given, allowing for automatic de-embedding of the present TFEAR equivalent circuit. Quality factors Q as high as 2500 in air have been recorded with motional resistance lower than 400 ohms. A first oscillator based on a TFEAR resonator was also designed and tested. PMID:20211764

Mareschal, Olivier; Loiseau, Sbastien; Fougerat, Aurlien; Valbin, Laurie; Lissorgues, Galle; Saez, Sebastien; Dolabdjian, Christophe; Bouregba, Rachid; Poullain, Gilles

2010-03-01

456

PZT Thin Film Piezoelectric Traveling Wave Motor  

NASA Technical Reports Server (NTRS)

With the development of micro-electro-mechanical systems (MEMS), its various applications are attracting more and more attention. Among MEMS, micro motors, electrostatic and electromagnetic, are the typical and important ones. As an alternative approach, the piezoelectric traveling wave micro motor, based on thin film material and integrated circuit technologies, circumvents many of the drawbacks of the above mentioned two types of motors and displays distinct advantages. In this paper we report on a lead-zirconate-titanate (PZT) piezoelectric thin film traveling wave motor. The PZT film with a thickness of 150 micrometers and a diameter of 8 mm was first deposited onto a metal substrate as the stator material. Then, eight sections were patterned to form the stator electrodes. The rotor had an 8 kHz frequency power supply. The rotation speed of the motor is 100 rpm. The relationship of the friction between the stator and the rotor and the structure of the rotor on rotation were also studied.

Shen, Dexin; Zhang, Baoan; Yang, Genqing; Jiao, Jiwei; Lu, Jianguo; Wang, Weiyuan

1995-01-01

457

Piezoelectric capacitive power generator from vibration energy  

NASA Astrophysics Data System (ADS)

A vibration-powered micro-power-generator has been presented in this paper, which has integrated two different energy harvesting mechanisms, e.g., Capacitive and Piezoelectric Mechanisms. The periodic vibration of the mass on movable electrode causes the variation of the capacitance, and the strain in the piezoelectric film. These two mechanisms can harvest the vibration energy and generate current in the output circuit. By using two different metals with large difference in working function as the two electrodes of the capacitor, our design, the combination of these two different scavenge mechanisms, can overcome the dependence of the traditional capacitive converter on the separate voltage source and improve the efficiency of power conversion. The volume of the designed device is less than 0.8 cm 3. The simulated results reveal that this energy converter can provide an average output power of 82.21?W at an external vibration with a frequency of 111.4 Hz and amplitude of 0.2g.

Zhang, Yangjian; Li, Lin; San, Haisheng; Chen, Xuyuan

2008-03-01

458

Characterization of Piezoelectric Stack Actuators for Vibrothermography  

NASA Astrophysics Data System (ADS)

Vibrothermography, also known as Sonic IR and thermosonics, is an NDE technique for finding cracks and flaws based on vibration-induced frictional rubbing of unbonded surfaces. The vibration is usually generated by a piezoelectric stack actuator which transduces electrical energy into large amplitude mechanical vibrations. The amplitude and impedance transfer characteristics of the transducer system control the vibration of the sample. Within a linear contact (no tip chatter) model, the interaction between the transducer system and the specimen can be characterized using the theory of linear time-invariant (LTI) systems and electro-mechanical Norton equivalence. We present quantitative measurements of the performance of piezoelectric stack actuators in a vibrothermography excitation system and investigate the effect of actuator performance and specimen characteristics on the induced vibration in the specimen. We show that the system resonances generated because of metal-metal contact of specimen and actuator are broken by adding a couplant between specimen and actuator. Finally, we give criteria for actuator and couplant selection for vibrothermography.

Vaddi, Jyani; Reusser, Ricky; Holland, Stephen D.

2011-06-01

459

Piezoelectric valve actuator for flexible diesel operation  

NASA Astrophysics Data System (ADS)

Mide Technology Corporation, under the supervision of the U.S. Army, is developing fast hydraulic valve technologies for fuel injection systems. Mide aims to address the Army's 21st Century Vehicle programs by providing the flexibility to achieve economic, environmentally friendly, and power dense diesel operation from a single platform. The technology couples a highly efficient gained piezoelectric actuator to a diesel unit injector's control valve spool. Piezoelectric actuation enables proportional authority over the injector's control valve, as opposed to traditional digital (on/off) operation. This authority allows the integrated device to provide electronically controlled fuel injection rate shaping capability. Each injection event profile may be independently shaped to govern diesel engine operation in one of three selectable modes: Lean, for fuel efficiency; Clean, for reduced emissions; Mean, for improved battlefield performance. To date, Mide has shown injection rate shaping capability in the laboratory using the industry standard "rate tube test" to measure injection profiles. Future development will focus on an engine demonstration of Lean, Clean, and Mean operating mode flexibility using rate shaping technology.

MacLachlan, Brian J.; Elvin, Niell; Blaurock, Carl; Keegan, N. J.

2004-07-01

460

Nonlinear free vibration of piezoelectric nanobeams incorporating surface effects  

NASA Astrophysics Data System (ADS)

In this study, the nonlinear free vibration of piezoelectric nanobeams incorporating surface effects (surface elasticity, surface tension, and surface density) is studied. The governing equation of the piezoelectric nanobeam is derived within the framework of Euler-Bernoulli beam theory with the von Krmn geometric nonlinearity. In order to satisfy the balance conditions between the nanobeam bulk and its surfaces, the component of the bulk stress, ?zz, is assumed to vary linearly through the nanobeam thickness. An exact solution is obtained for the natural frequencies of a simply supported piezoelectric nanobeam in terms of the Jacobi elliptic functions using the free vibration mode shape of the corresponding linear problem. Then, the influences of the surface effects and the piezoelectric field on the nonlinear free vibration of nanobeams made of aluminum and silicon with positive and negative surface elasticity, respectively, have been studied for various properties of the piezoelectric field, various nanobeam sizes and amplitude ratios. It is observed that if the Youngs modulus of a nanobeam is lower, the effect of the piezoelectric field on the frequency ratios (FRs) of the nanobeam will be greater. In addition, it is seen that by increasing the nanobeam length so that the nanobeam cross section is set to be constant, the surface effects and the piezoelectric field with negative voltage values increases the FRs, whereas it is the other way around when the nanobeam cross section is assumed to be dependent on the length of the nanobeam.

Hosseini-Hashemi, Shahrokh; Nahas, Iman; Fakher, Mahmood; Nazemnezhad, Reza

2014-03-01

461

Piezoelectric PU/PVDF electrospun scaffolds for wound healing applications.  

PubMed

Previous studies have shown that piezoelectric materials may be used to prepare bioactive electrically charged surfaces. In the current study, polyurethane/polyvinylidene fluoride (PU/PVDF) scaffolds were prepared by electrospinning. The mechanical property and piezoelectric property of the scaffolds were evaluated. The crystalline phase of PVDF in the scaffolds was characterised by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). In vitro cell culture was performed to investigate cytocompatibility of the scaffolds. Wound-healing assay, cell-adhesion assay, quantitative RT-PCR and Western blot analyses were performed to investigate piezoelectric effect of the scaffolds on fibroblast activities. Fur