Science.gov

Sample records for hard piezoelectric lead-free

  1. Characterization of Hard Piezoelectric Lead-Free Ceramics

    PubMed Central

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

    2010-01-01

    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 188°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 lead-free materials are desirable. PMID:19686966

  2. Progress in engineering high strain lead-free piezoelectric ceramics

    PubMed Central

    Leontsev, Serhiy O; Eitel, Richard E

    2010-01-01

    Environmental concerns are strongly driving the need to replace the lead-based piezoelectric materials currently employed as multilayer actuators. The current review describes both compositional and structural engineering approaches to achieve enhanced piezoelectric properties in lead-free materials. The review of the compositional engineering approach focuses on compositional tuning of the properties and phase behavior in three promising families of lead-free perovskite ferroelectrics: the titanate, alkaline niobate and bismuth perovskites and their solid solutions. The ‘structural engineering’ approaches focus instead on optimization of microstructural features including grain size, grain orientation or texture, ferroelectric domain size and electrical bias field as potential paths to induce large piezoelectric properties in lead-free piezoceramics. It is suggested that a combination of both compositional and novel structural engineering approaches will be required in order to realize viable lead-free alternatives to current lead-based materials for piezoelectric actuator applications. PMID:27877343

  3. Tonpilz Underwater Acoustic Transducer Integrating Lead-free Piezoelectric Material

    NASA Astrophysics Data System (ADS)

    Rouffaud, Rémi; Granger, Christian; Hladky-Hennion, Anne-Christine; Thi, Mai Pham; Levassort, Franck

    A Tonpilz transducer based on lead-free piezoelectric material was fabricated, modeled and characterized. The stack is composed of two rings of doped BaTiO3. This composition was initially chosen due to good electromechanical performance (kt at 40%) and high mechanical quality factor (Qm over 500). Comparison of the displacement at the center of the head mass was performed with a PZT-based Tonpilz with the same design for a center frequency at 22 kHz.

  4. KNN–NTK composite lead-free piezoelectric ceramic

    SciTech Connect

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

    2014-10-21

    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.

  5. A lead-free piezoelectric transformer in radial vibration modes.

    PubMed

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

    2007-03-01

    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.

  6. Defect Engineering of Lead-Free Piezoelectrics with High Piezoelectric Properties and Temperature-Stability.

    PubMed

    Feng, Yu; Li, Wei-Li; Xu, Dan; Qiao, Yu-Long; Yu, Yang; Zhao, Yu; Fei, Wei-Dong

    2016-04-13

    The high piezoelectricity of ABO3-type lead-free piezoelectric materials can be achieved with the help of either morphotropic phase boundary (MPB) or polymorphic phase transition (PPT). Here, we propose a new defect engineering route to the excellent piezoelectric properties, in which doped smaller acceptor and donor ions substituting bivalent A-sites are utilized to bring local lattice distortion and lower symmetry. A concrete paradigm is presented, (Li-Al) codoped BaTiO3 perovskite, that exhibits a largely thermo-stable piezoelectric constant (>300 pC/N) and huge mechanical quality factor (>2000). A systematic analysis including theoretical analysis and simulation results indicates that the Li(+) and Al(3+) ions are inclined to occupy the neighboring A-sites in the lattice and constitute a defect dipole (ionic pairs). The defect dipoles possess a kind of dipole moment which tends to align directionally after thermo-electric treatment. A mechanism related to the defect symmetry principle, phase transition, and defect migration is proposed to explain the outstanding piezoelectric properties. The present study opens a new development window for excellent piezoelectricity and provides a promising route to the potential utilization of lead-free piezoelectrics in high power applications.

  7. Piezoelectric Active Humidity Sensors Based on Lead-Free NaNbO3 Piezoelectric Nanofibers

    PubMed Central

    Gu, Li; Zhou, Di; Cao, Jun Cheng

    2016-01-01

    The development of micro-/nano-scaled energy harvesters and the self-powered sensor system has attracted great attention due to the miniaturization and integration of the micro-device. In this work, lead-free NaNbO3 piezoelectric nanofibers with a monoclinic perovskite structure were synthesized by the far-field electrospinning method. The flexible active humidity sensors were fabricated by transferring the nanofibers from silicon to a soft polymer substrate. The sensors exhibited outstanding piezoelectric energy-harvesting performance with output voltage up to 2 V during the vibration process. The output voltage generated by the NaNbO3 sensors exhibited a negative correlation with the environmental humidity varying from 5% to 80%, where the peak-to-peak value of the output voltage generated by the sensors decreased from 0.40 to 0.07 V. The sensor also exhibited a short response time, good selectively against ethanol steam, and great temperature stability. The piezoelectric active humidity sensing property could be attributed to the increased leakage current in the NaNbO3 nanofibers, which was generated due to proton hopping among the H3O+ groups in the absorbed H2O layers under the driving force of the piezoelectric potential. PMID:27338376

  8. Piezoelectric Active Humidity Sensors Based on Lead-Free NaNbO₃ Piezoelectric Nanofibers.

    PubMed

    Gu, Li; Zhou, Di; Cao, Jun Cheng

    2016-06-07

    The development of micro-/nano-scaled energy harvesters and the self-powered sensor system has attracted great attention due to the miniaturization and integration of the micro-device. In this work, lead-free NaNbO₃ piezoelectric nanofibers with a monoclinic perovskite structure were synthesized by the far-field electrospinning method. The flexible active humidity sensors were fabricated by transferring the nanofibers from silicon to a soft polymer substrate. The sensors exhibited outstanding piezoelectric energy-harvesting performance with output voltage up to 2 V during the vibration process. The output voltage generated by the NaNbO₃ sensors exhibited a negative correlation with the environmental humidity varying from 5% to 80%, where the peak-to-peak value of the output voltage generated by the sensors decreased from 0.40 to 0.07 V. The sensor also exhibited a short response time, good selectively against ethanol steam, and great temperature stability. The piezoelectric active humidity sensing property could be attributed to the increased leakage current in the NaNbO₃ nanofibers, which was generated due to proton hopping among the H₃O⁺ groups in the absorbed H₂O layers under the driving force of the piezoelectric potential.

  9. First-principles study on novel lead-free piezoelectric materials

    NASA Astrophysics Data System (ADS)

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

    2011-12-01

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

  10. Lead-free KNLNT piezoelectric ceramics for high-frequency ultrasonic transducer application.

    PubMed

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

    2009-03-01

    This paper presents the latest development of a lead-free piezoelectric ceramic and its application to transducers suitable for high-frequency ultrasonic imaging. A lead-free piezoelectric ceramic with formula of (K(0.5)Na(0.5))(0.97)Li(0.03)(Nb(0.9) Ta(0.1))O(3) (abbreviated as KNLNT-0.03/0.10) was fabricated and characterized. The material was found to have a clamped dielectric constant epsilon(33)(S)/epsilon(0)=890, piezoelectric coefficient d(33)=245 pC/N, electromechanical coupling factor k(t)=0.42 and Curie temperature T(c)>300 degrees C. High-frequency (40 MHz) ultrasound transducers were successfully fabricated with the lead-free material. A representative lead-free transducer had a bandwidth of 45%, two-way insertion loss of -18 dB. This performance is comparable to reported performances of popular lead-based transducers. The comparison results suggest that the lead-free piezoelectric material may serve as an alternative to lead-based piezoelectric materials for high-frequency ultrasonic transducer applications.

  11. Advances in Lead-Free Piezoelectric Materials for Sensors and Actuators

    PubMed Central

    Aksel, Elena; Jones, Jacob L.

    2010-01-01

    Piezoelectrics have widespread use in today’s 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

  12. Lead-free piezoelectric materials and ultrasonic transducers for medical imaging

    NASA Astrophysics Data System (ADS)

    Taghaddos, Elaheh; Hejazi, Mehdi; Safari, Ahmad

    2015-06-01

    Piezoelectric materials have been vastly used in ultrasonic transducers for medical imaging. In this paper, firstly, the most promising lead-free compositions with perovskite structure for medical imaging applications have been reviewed. The electromechanical properties of various lead-free ceramics, composites, and single crystals based on barium titanate, bismuth sodium titanate, potassium sodium niobate, and lithium niobate are presented. Then, fundamental principles and design considerations of ultrasonic transducers are briefly described. Finally, recent developments in lead-free ultrasonic probes are discussed and their acoustic performance is compared to lead-based transducers. Focused transducers with different beam focusing methods such as lens focusing and mechanical shaping are explained. Additionally, acoustic characteristics of lead-free probes including the pulse-echo results as well as their imaging capabilities for various applications such as phantom imaging, in vitro intravascular ultrasound imaging of swine aorta, and in vivo or ex vivo imaging of human eyes and skin are reviewed.

  13. Lead-Free Piezoelectric Diaphragm Biosensors Based on Micro-Machining Technology and Chemical Solution Deposition

    PubMed Central

    Li, Xiaomeng; Wu, Xiaoqing; Shi, Peng; Ye, Zuo-Guang

    2016-01-01

    In this paper, we present a new approach to the fabrication of integrated silicon-based piezoelectric diaphragm-type biosensors by using sodium potassium niobate-silver niobate (0.82KNN-0.18AN) composite lead-free thin film as the piezoelectric layer. The piezoelectric diaphragms were designed and fabricated by micro-machining technology and chemical solution deposition. The fabricated device was very sensitive to the mass changes caused by various targets attached on the surface of diaphragm. The measured mass sensitivity value was about 931 Hz/μg. Its good performance shows that the piezoelectric diaphragm biosensor can be used as a cost-effective platform for nucleic acid testing. PMID:26771617

  14. Lead-Free Piezoelectric Diaphragm Biosensors Based on Micro-Machining Technology and Chemical Solution Deposition.

    PubMed

    Li, Xiaomeng; Wu, Xiaoqing; Shi, Peng; Ye, Zuo-Guang

    2016-01-12

    In this paper, we present a new approach to the fabrication of integrated silicon-based piezoelectric diaphragm-type biosensors by using sodium potassium niobate-silver niobate (0.82KNN-0.18AN) composite lead-free thin film as the piezoelectric layer. The piezoelectric diaphragms were designed and fabricated by micro-machining technology and chemical solution deposition. The fabricated device was very sensitive to the mass changes caused by various targets attached on the surface of diaphragm. The measured mass sensitivity value was about 931 Hz/μg. Its good performance shows that the piezoelectric diaphragm biosensor can be used as a cost-effective platform for nucleic acid testing.

  15. Miniature Ultrasonic Motor Using Shear Mode of Potassium Sodium Niobate-Based Lead-Free Piezoelectric Ceramics

    NASA Astrophysics Data System (ADS)

    Li, Enzhu; Sasaki, Ryo; Hoshina, Takuya; Takeda, Hiroaki; Tsurumi, Takaaki

    2009-09-01

    A miniature piezoelectric ultrasonic motor (USM) using the shear mode of (K,Na)NbO3 (KNN)-based lead-free piezoelectric ceramics was developed. The motor can be driven in the shearing and bending vibration modes. By using the finite-element method, the motor vibration modes and driving mechanism were modeled. Both the “soft-type” (high-d USM) and “hard-type” (high-Qm USM) KNN-based lead-free piezoelectric ceramics were employed to clarify the characteristics of USMs. The experimental results reveal that the high-d USM widens the band of operational frequency in both vibration modes. In the shearing vibration mode, the high-d USM showed a revolution speed of 416 rpm, a torque of 41.5 µN m, and an efficiency of 0.6%, whereas the high-Qm USM showed the same characteristics of 313 rpm, 19.6 µN m and 1.6%, respectively. In the bending vibration mode, the characteristics of the high-Qm USM were 376 rpm, 51.4 µN m and 0.4%; however, the characters of the high-d USM deteriorated owing to the shift in resonance frequency caused by heat generation.

  16. Giant piezoelectricity in potassium-sodium niobate lead-free ceramics.

    PubMed

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

    2014-02-19

    Environment protection and human health concern is the driving force to eliminate the lead from commercial piezoelectric materials. In 2004, Saito et al. [ Saito et al., Nature , 2004 , 432 , 84 . ] developed an alkali niobate-based perovskite solid solution with a peak piezoelectric constant d33 of 416 pC/N when prepared in the textured polycrystalline form, intriguing the enthusiasm of developing high-performance lead-free piezoceramics. Although much attention has been paid on the alkali niobate-based system in the past ten years, no significant breakthrough in its d33 has yet been attained. Here, we report an alkali niobate-based lead-free piezoceramic with the largest d33 of ∼490 pC/N ever reported so far using conventional solid-state method. In addition, this material system also exhibits excellent integrated performance with d33∼390-490 pC/N and TC∼217-304 °C by optimizing the compositions. This giant d33 of the alkali niobate-based lead-free piezoceramics is ascribed to not only the construction of a new rhombohedral-tetragonal phase boundary but also enhanced dielectric and ferroelectric properties. Our finding may pave the way for "lead-free at last".

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

    PubMed Central

    2014-01-01

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

  18. Piezoelectric Properties of CuO-Doped (K,Na)NbO3 Lead-Free Ceramics Synthesized with Hydrothermal Powders

    NASA Astrophysics Data System (ADS)

    Yokouchi, Yuriko; Maeda, Takafumi; Bornmann, Peter; Hemsel, Tobias; Morita, Takeshi

    2013-07-01

    We report the piezoelectric properties of CuO-doped hydrothermal (K,Na)NbO3 ceramics that can be applied as hard-type lead-free piezoelectric ceramics. To date, we have succeeded in synthesizing high-quality KNbO3 and NaNbO3 powders by the hydrothermal method, which is based on an ionic reaction at high temperature (around 210 °C) and pressure. Increasing both the piezoelectric constant d and the mechanical quality factor (Qm) is important for resonance-type piezoelectric devices, such as ultrasonic motors and transformers. CuO doping into hydrothermal (K,Na)NbO3 ceramics was examined to realize hard-type lead-free piezoelectric ceramics. By doping with 1.2 mol % CuO, Qm was increased and the dielectric loss (tan δ) was decreased to 0.5%. The grain size was also influenced by the amount of CuO doping, which indicates that Qm is related to the density. To achieve a higher Qm value, the grain size is required to be less than 5 µm however, excessive CuO doping leads to anomalous grain growth. Optimal piezoelectric properties were obtained for 1.2 mol % CuO-doped (K,Na)NbO3; k31 = 0.32, d31 = -44 pC/N, Qm (radial) = 959, and tan δ= 0.5%. These characteristics showed that CuO doping with hydrothermal powders is effective for obtaining hard-type ceramics, and the mechanical quality factor is more than ten times higher than that of nondoped hydrothermal (K,Na)NbO3 ceramics. Therefore, compared with the conventional solid-state method, we could succeed in obtaining hard-type ceramics by a simple and short process.

  19. Effect of gamma radiation on micromechanical hardness of lead-free solder joint

    SciTech Connect

    Paulus, Wilfred; Rahman, Irman Abdul; Jalar, Azman; Kamil, Insan; Bakar, Maria Abu; Yusoff, Wan Yusmawati Wan

    2015-09-25

    Lead-free solders are important material in nano and microelectronic surface mounting technology for various applications in bio medicine, environmental monitoring, spacecraft and satellite instrumentation. Nevertheless solder joint in radiation environment needs higher reliability and resistance to any damage caused by ionizing radiations. In this study a lead-free 99.0Sn0.3Ag0.7Cu wt.% (SAC) solder joint was developed and subjected to various doses of gamma radiation to investigate the effects of the ionizing radiation to micromechanical hardness of the solder. Averaged hardness of the SAC joint was obtained from nanoindentation test. The results show a relationship between hardness values of indentations and the increment of radiation dose. Highest mean hardness, 0.2290 ± 0.0270 GPa was calculated on solder joint which was exposed to 5 Gray dose of gamma radiation. This value indicates possible radiation hardening effect on irradiated solder. The hardness gradually decreased to 0.1933 ± 0.0210 GPa and 0.1631 ± 0.0173 GPa when exposed to doses 50 and 500 gray respectively. These values are also lower than the hardness of non irradiated sample which was calculated as 0.2084 ± 0.0.3633 GPa indicating possible radiation damage and needs further related atomic dislocation study.

  20. Lead-Free Piezoceramics: Revealing the Role of the Rhombohedral-Tetragonal Phase Coexistence in Enhancement of the Piezoelectric Properties.

    PubMed

    Rubio-Marcos, Fernando; López-Juárez, Rigoberto; Rojas-Hernandez, Rocio E; del Campo, Adolfo; Razo-Pérez, Neftalí; Fernandez, Jose F

    2015-10-21

    Until now, lead zirconate titanate (PZT) based ceramics are the most widely used in piezoelectric devices. However, the use of lead is being avoided due to its toxicity and environmental risks. Indeed, the attention in piezoelectric devices has been moved to lead-free ceramics, especially on (K,Na)NbO3-based materials, due to growing environmental concerns. Here we report a systematic evaluation of the effects of the compositional modifications induced by replacement of the B-sites with Sb(5+) ions in 0.96[(K0.48Na0.52)0.95Li0.05Nb1-xSbxO3]-0.04[BaZrO3] lead-free piezoceramics. We show that this compositional design is the driving force for the development of the high piezoelectric properties. So, we find that this phenomenon can be explained by the stabilization of a Rhombohedral-Tetragonal (R-T) phase boundary close to room temperature, that facilities the polarization process of the system and exhibits a significantly high piezoelectric response with a d33 value as high as ∼400 pC/N, which is comparable to part soft PZTs. As a result, we believe that the general strategy and design principles described in this study open the possibility of obtaining (K,Na)NbO3-based lead-free ceramics with enhanced properties, expanding their application range.

  1. High performance Aurivillius phase sodium-potassium bismuth titanate lead-free piezoelectric ceramics with lithium and cerium modification

    NASA Astrophysics Data System (ADS)

    Wang, Chun-Ming; Wang, Jin-Feng

    2006-11-01

    The piezoelectric properties of the lithium and cerium modified A-site vacancies sodium-potassium bismuth titanate (NKBT) lead-free piezoceramics are investigated. The piezoelectric activity of NKBT ceramics is significantly improved by the modification of lithium and cerium. The Curie temperature TC, piezoelectric coefficient d33, and mechanical quality factor Qm for the NKBT ceramics modified with 0.10mol% (LiCe) are found to be 660°C, 25pC/N, and 3135, respectively. The Curie temperature gradually decreases from 675to650°C with the increase of (LiCe) modification. The dielectric spectroscopy shows that all the samples possess stable piezoelectric properties, demonstrating that the (LiCe) modified NKBT-based ceramics are the promising candidates for high temperature applications.

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

    NASA Astrophysics Data System (ADS)

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

    2015-01-01

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

  3. Direct Writing of Patterned, Lead-Free Nanowire Aligned Flexible Piezoelectric Device.

    PubMed

    Gao, Meng; Li, Lihong; Li, Wenbo; Zhou, Haihua; Song, Yanlin

    2016-08-01

    A high-performance flexible piezoelectric nanogenerator (PNG) is fabricated by a direct writing method, which acquires both patterned piezoelectric structure and aligned piezoelectric nanowires simultaneously. The voltage output of the as-prepared PNG is nearly 400% compared with that of the traditional spin-coated device due to the effective utilization of stress. This facile printing approach provides an efficient strategy for significant improvement of the piezoresponse.

  4. Piezoelectric and ferroelectric properties of lead-free niobium-rich potassium lithium tantalate niobate single crystals

    SciTech Connect

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

    2014-01-01

    Graphical abstract: - Highlights: • Lead-free K{sub 0.95}Li{sub 0.05}Ta{sub 1−x}Nb{sub x}O{sub 3} single crystals were grown using the top-seeded melt growth method. • The piezoelectric and ferroelectric properties of as-grown crystals were systematically investigated. • The piezoelectric properties are very attractive, e.g. for x = 0.60 composition, k{sub t} ≈ 70%, k{sub 31} ≈ 70%, k{sub 33} ≈ 77%, d{sub 31} ≈ 230 pC/N, d{sub 33} ≈ 600 pC/N. • The coercive fields of P–E hysteresis loops are quite small, about or less than 1 kV/mm. - Abstract: Lead-free potassium lithium tantalate niobate single crystals with the composition of K{sub 0.95}Li{sub 0.05}Ta{sub 1−x}Nb{sub x}O{sub 3} (abbreviated as KLTN, x = 0.51, 0.60, 0.69, 0.78) were grown using the top-seeded melt growth method. Their piezoelectric and ferroelectric properties in as-grown crystals have been systematically investigated. The phase transitions and Curie temperatures were determined from dielectric and pyroelectric measurements. Piezoelectric coefficients and electromechanical coupling factors in thickness mode, length-extensional mode and longitudinal mode were obtained. The piezoelectric properties are very attractive, e.g. for x = 0.60 composition, k{sub t} ≈ 70%, k{sub 31} ≈ 70%, k{sub 33} ≈ 77%, d{sub 31} ≈ 230 pC/N, d{sub 33} ≈ 600 pC/N are comparable to the lead-based PZT composition. The polarization versus electric field hysteresis loops show saturated shapes. In short, lead-free niobium-rich KLTN system possesses comparable properties to those in important lead-based piezoelectric material nowadays.

  5. Piezoelectric d36 in-plane shear-mode of lead-free BZT-BCT single crystals for torsion actuation

    NASA Astrophysics Data System (ADS)

    Berik, P.; Chang, W.-Y.; Jiang, X.

    2017-01-01

    We report the study of piezoelectric direct torsion actuation mechanism using lead-free piezoelectric d36 in-plane shear-mode BZT-BCT single crystals. The generated angle of twist of the piezoelectric torsion actuator was obtained from the transverse deflection measurement using a laser vibrometer. The bi-morph torsional actuator, consisting of two lead-free piezoelectric BZT-BCT in-plane shear-mode single crystals with a giant piezoelectric d36 shear strain coefficient of 1590 pC/N, provided a rate of twist of 34.12 mm/m under a quasi-static 15 V drive. The experimental benchmark was further modelled and verified by the ANSYS software using three dimensional (3D) piezoelectric finite elements. The experimental results revealed that lead-free piezoelectric BZT-BCT d36-mode single crystal is a superior candidate for piezoelectric torsion actuation. This lead-free piezoelectric BZT-BCT d36-mode torsion actuator can be effectively applied in torsional deformation control by taking into account the environmental considerations.

  6. Phase transition and piezoelectric properties of Nd3+ doped nonstoichiometric (K,Na)NbO3-based lead free ceramics

    NASA Astrophysics Data System (ADS)

    Xing, Jie; Tan, Zhi; Jiang, Laiming; Wu, Yangjie; Yue, Yang; Chen, Qiang; Wu, Jiagang; Zhang, Wen; Xiao, Dingquan; Zhu, Jianguo

    2017-01-01

    0.968[(K0.48Na0.52)]1-3xNdxNb0.95+ySb0.05O3-0.032(Bi0.5Na0.5)ZrO3[KNNdxNb0.95+yS-BNZ] lead-free piezoelectric ceramics were prepared via conventional solid state technique for improving the piezoelectric properties. The influences of Nd3+ with excess Nb5+ on the phase structure, electrical properties, and temperature stability were investigated systematically. The rhombohedral-tetragonal phase boundary was observed in the ceramics with 0.001 ≤ x ≤ 0.004, y ≥ 0.01 at room temperature. Rietveld refinement is performed to explore the phase evolution in ceramics. There is a piezoelectric property enhancement in the ceramic with x = 0.001 y = 0.01: d33 = 414 pC/N, kp ˜ 48%, and TC ˜ 227 °C. All results suggest that KNNdxNb0.95+yS-BNZ ceramics developed in this study are expected to be suitable substitutes for lead-based ceramics.

  7. Effect of orthorhombic-tetragonal phase transition on structure and piezoelectric properties of KNN-based lead-free ceramics.

    PubMed

    Zhang, Yang; Li, Lingyu; Shen, Bo; Zhai, Jiwei

    2015-05-07

    (1 - x)(K0.5Na0.5)0.95Li0.05Nb0.93Sb0.07O3-xSrZrO3 ((1 - x)KNLNS-xSZ) lead free piezoelectric ceramics have been prepared by the conventional solid state reaction method, via adjusting the orthorhombic-tetragonal phase transition temperature to near room temperature with doping SrZrO3, and the effects of SrZrO3 content on polymorphic phase transition have been investigated. These results show that the phase structure of the ceramics was changed from orthorhombic to tetragonal at x ≥ 0.02 mol, and the orthorhombic-tetragonal phase transition temperature was modified to around room temperature with increasing SrZrO3. Remarkable piezoelectric and ferroelectric properties has been obtained in (1 - x)KNLNS-xSZ system with x = 0.02, which showed a piezoelectric parameter of d33 = 256 pC N(-1), Curie temperature Tc = 270 °C, strain levels of 0.16% at 50 kV cm(-1), remnant polarization Pr = 24.9 μC cm(-2) and coercive field Ec = 10.6 kV cm(-1).

  8. Giant Piezoelectricity and High Curie Temperature in Nanostructured Alkali Niobate Lead-Free Piezoceramics through Phase Coexistence.

    PubMed

    Wu, Bo; Wu, Haijun; Wu, Jiagang; Xiao, Dingquan; Zhu, Jianguo; Pennycook, Stephen J

    2016-11-30

    Because of growing environmental concerns, the development of lead-free piezoelectric materials with enhanced properties has become of great interest. Here, we report a giant piezoelectric coefficient (d33) of 550 pC/N and a high Curie temperature (TC) of 237 °C in (1-x-y)K1-wNawNb1-zSbzO3-xBiFeO3-yBi0.5Na0.5ZrO3 (KNwNSz-xBF-yBNZ) ceramics by optimizing x, y, z, and w. Atomic-resolution polarization mapping by Z-contrast imaging reveals the intimate coexistence of rhombohedral (R) and tetragonal (T) phases inside nanodomains, that is, a structural origin for the R-T phase boundary in the present KNN system. Hence, the physical origin of high piezoelectric performance can be attributed to a nearly vanishing polarization anisotropy and thus low domain wall energy, facilitating easy polarization rotation between different states under an external field.

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

    PubMed

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

    2014-01-01

    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.

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

    SciTech Connect

    Khansur, Neamul H.; Daniels, John E.; Groh, Claudia; Jo, Wook; Webber, Kyle G.; Reinhard, Christina; Kimpton, Justin A.

    2014-03-28

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

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

    NASA Astrophysics Data System (ADS)

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

    2013-09-01

    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 ɛr 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 µW under vibration at 393 Hz and 10 m/s2.

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

    PubMed

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

    2014-02-01

    (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.

  13. The ageing and de-ageing behaviour of (Ba0.85Ca0.15)(Ti0.9Zr0.1)O3 lead-free piezoelectric ceramics

    NASA Astrophysics Data System (ADS)

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

    2015-09-01

    Ageing behaviour usually occurs in acceptor-doped piezoelectric materials (e.g., hard lead zirconate titanate) and exhibits the development of a pinched or shifted hysteresis loop over time. Although no pinched hysteresis loop was observed for lead-free (Ba0.85Ca0.15)(Ti0.9Zr0.1)O3 material, this study showed that the piezoelectric properties change over time in the poled state. The shift of the hysteresis loop along the electric field axis and the development of asymmetry in strain and permittivity hysteresis loop were observed during the ageing process. The origin of this ageing behaviour is proposed to be local defect dipoles and the migration of the charged defects to the grain boundaries. The reorientation of the defect dipole contributes to a fast but unstable ageing mechanism in this material while the migration of the charged defects contributes to a slow but more stable mechanism.

  14. High Curie point CaBi2Nb2O9 thin films: A potential candidate for lead-free thin-film piezoelectrics

    NASA Astrophysics Data System (ADS)

    Simões, A. Z.; Ries, A.; Riccardi, C. S.; Gonzalez, A. H. M.; Longo, E.; Varela, J. A.

    2006-10-01

    CaBi2Nb2O9 (CBNO) thin films deposited on platinum coated silicon substrates by the polymeric precursor method exhibited good structural, dielectric, and piezoelectric characteristics. Capacitance-voltage measurements indicated good ferroelectric polarization switching characteristics. Remanent polarization and drive voltage values were 4.2μC /cm2 and 1.7V for a maximum applied voltage of 10V. The film has a piezoelectric coefficient d33 equal to 60pm/V, current density of 0.7μA/cm2, and Curie temperature of 940°C. The polar-axis-oriented CBNO is a promising candidate for use in lead-free high Curie point in ferroelectric and piezoelectric devices.

  15. Temperature dependent structures and properties of Bi0.5Na0.5TiO3-based lead free piezoelectric composite.

    PubMed

    Zhang, Ji; Sun, Lei; Geng, Xiao-Yu; Zhang, Bin-Bin; Yuan, Guo-Liang; Zhang, Shan-Tao

    2016-07-05

    The thermal depolarization around 100 °C of the Bi0.5Na0.5TiO3-based piezoelectric solid solutions leads to the disappearance of macroscopic ferroelectric/piezoelectric properties and remains a long-standing obstacle for their actual applications. In this communication, we report lead-free piezoelectric composites of 0.94Bi0.5Na0.5TiO3-0.06BaTiO3:0.5ZnO (BNT-6BT:0.5ZnO, where 0.5 is the mole ratio of ZnO to BNT-6BT) with deferred thermal depolarization, which is experimentally confirmed by systematic temperature dependent dielectric, ferroelectric, piezoelectric measurements. Especially, based on temperature dependent X-ray diffraction measurements on unpoled and poled samples, thermal depolarization is confirmed to have no relationship with the structural phase transition, the possible mechanism for the deferred thermal depolarization is correlated with the ZnO-induced local electric field which can suppress the depolarization field. We believe our results may be helpful for understanding the origin of thermal depolarization in BNT-based piezoelectric materials, and thus provide an effective way to overcoming this obstacle.

  16. Lead-free piezoelectrics: V3+ to V5+ ion conversion promoting the performances of V-doped Zinc Oxide

    NASA Astrophysics Data System (ADS)

    Laurenti, M.; Castellino, M.; Perrone, D.; Asvarov, A.; Canavese, G.; Chiolerio, A.

    2017-02-01

    Vanadium doped ZnO (VZO) thin films were grown by RF magnetron sputtering, starting from a ZnO:V ceramic target. The crystal structure, chemical composition, electric and piezoelectric properties of the films were investigated either on the as-grown thin films or after a post-deposition rapid thermal annealing (RTA) treatment performed at 600 °C for different lengths of time (1 and 5 min) in an oxygen atmosphere. Substitutional doping of Zn2+ with V3+ and V5+ ions strongly deteriorated the hexagonal wurtzite ZnO structure of the as-grown thin films due to lattice distortion. The resulting slight amorphization led to a poor piezoelectric response and higher resistivity. After the RTA treatment, strong c-axis oriented VZO thin films were obtained, together with a partial conversion of the starting V3+ ions into V5+. The improvement of the crystal structure and the stronger polarity of both V3+ – O and V5+ – O chemical bonds, together with the corresponding easier rotation under the application of an external electric field, positively affected the piezoelectric response and increased conductivity. This was confirmed by closed-loop butterfly piezoelectric curves, by a maximum d33 piezoelectric coefficient of 85 pm·V‑1, and also by ferroelectric switching domains with a well-defined polarization hysteresis curve, featuring a residual polarization of 12.5 μC•cm‑2.

  17. Lead-free piezoelectrics: V3+ to V5+ ion conversion promoting the performances of V-doped Zinc Oxide

    PubMed Central

    Laurenti, M.; Castellino, M.; Perrone, D.; Asvarov, A.; Canavese, G.; Chiolerio, A.

    2017-01-01

    Vanadium doped ZnO (VZO) thin films were grown by RF magnetron sputtering, starting from a ZnO:V ceramic target. The crystal structure, chemical composition, electric and piezoelectric properties of the films were investigated either on the as-grown thin films or after a post-deposition rapid thermal annealing (RTA) treatment performed at 600 °C for different lengths of time (1 and 5 min) in an oxygen atmosphere. Substitutional doping of Zn2+ with V3+ and V5+ ions strongly deteriorated the hexagonal wurtzite ZnO structure of the as-grown thin films due to lattice distortion. The resulting slight amorphization led to a poor piezoelectric response and higher resistivity. After the RTA treatment, strong c-axis oriented VZO thin films were obtained, together with a partial conversion of the starting V3+ ions into V5+. The improvement of the crystal structure and the stronger polarity of both V3+ – O and V5+ – O chemical bonds, together with the corresponding easier rotation under the application of an external electric field, positively affected the piezoelectric response and increased conductivity. This was confirmed by closed-loop butterfly piezoelectric curves, by a maximum d33 piezoelectric coefficient of 85 pm·V−1, and also by ferroelectric switching domains with a well-defined polarization hysteresis curve, featuring a residual polarization of 12.5 μC∙cm−2. PMID:28165040

  18. Lead-free piezoelectrics: V(3+) to V(5+) ion conversion promoting the performances of V-doped Zinc Oxide.

    PubMed

    Laurenti, M; Castellino, M; Perrone, D; Asvarov, A; Canavese, G; Chiolerio, A

    2017-02-06

    Vanadium doped ZnO (VZO) thin films were grown by RF magnetron sputtering, starting from a ZnO:V ceramic target. The crystal structure, chemical composition, electric and piezoelectric properties of the films were investigated either on the as-grown thin films or after a post-deposition rapid thermal annealing (RTA) treatment performed at 600 °C for different lengths of time (1 and 5 min) in an oxygen atmosphere. Substitutional doping of Zn(2+) with V(3+) and V(5+) ions strongly deteriorated the hexagonal wurtzite ZnO structure of the as-grown thin films due to lattice distortion. The resulting slight amorphization led to a poor piezoelectric response and higher resistivity. After the RTA treatment, strong c-axis oriented VZO thin films were obtained, together with a partial conversion of the starting V(3+) ions into V(5+). The improvement of the crystal structure and the stronger polarity of both V(3+) - O and V(5+) - O chemical bonds, together with the corresponding easier rotation under the application of an external electric field, positively affected the piezoelectric response and increased conductivity. This was confirmed by closed-loop butterfly piezoelectric curves, by a maximum d33 piezoelectric coefficient of 85 pm·V(-1), and also by ferroelectric switching domains with a well-defined polarization hysteresis curve, featuring a residual polarization of 12.5 μC∙cm(-2).

  19. Improvement of the piezoelectric properties in (K,Na)NbO{sub 3}-based lead-free piezoelectric ceramic with two-phase co-existing state

    SciTech Connect

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

    2015-06-07

    Two phases of (K,Na)NbO{sub 3} (KNN) co-exist in a KNN-based composite lead-free piezoelectric ceramic 0.910(K{sub 1−x}Na{sub x}){sub 0.86}Ca{sub 0.04}Li{sub 0.02}Nb{sub 0.85}O{sub 3−δ}–0.042K{sub 0.85}Ti{sub 0.85}Nb{sub 1.15}O{sub 5} –0.036BaZrO{sub 3}–0.0016Co{sub 3}O{sub 4}– 0.0025Fe{sub 2}O{sub 3}–0.0069ZnO system, over a wide range of Na fractions, where 0.56 ≤ x ≤ 0.75. The crystal systems of the two KNN phases are identified to tetragonal and orthorhombic by analyzing the synchrotron powder X-ray diffraction (XRD) data, high-resolution transmission electron microscopy (HR-TEM), and selected-area electron diffraction (SAD). In the range 0.33 ≤ x ≤ 0.50, the main component of the composite system is found to be single-phase KNN with a tetragonal structure. Granular nanodomains of the orthorhombic phase dispersed in the tetragonal matrix have been identified by HR-TEM and SAD for 0.56 ≤ x ≤ 0.75. Only a trace amount of the orthorhombic phase has been found in the SAD patterns at the composition x = 0.56. However, the number of orthorhombic nanodomains gradually increases with increasing Na content up to x < 0.75, as observed from the HR-TEM images. An abrupt increase and agglomeration of the nanodomains are observed at x = 0.75, where weak diffraction peaks of the orthorhombic phase have also become detectable from the XRD data. The maximum value of the electromechanical coupling coefficient, k{sub p} = 0.56, has been observed at the composition x = 0.56.

  20. Phase transition behavior and electrical properties of lead-free (Ba1-xCax)(Zr0.1Ti0.9)O3 piezoelectric ceramics

    NASA Astrophysics Data System (ADS)

    Tian, Ye; Chao, Xiaolian; Wei, Lingling; Liang, Pengfei; Yang, Zupei

    2013-05-01

    Lead-free (Ba1-xCax)(Zr0.1Ti0.9)O3(BCZT) ceramics were synthesized by conventional solid-state sintering process. The Ca ion substitutions on phase transition behavior, microstructure, ferroelectric and piezoelectric properties of BCZT ceramics were systemically investigated. The diffuse phase transition (DPT) behavior was suppressed, while the orthorhombic → tetragonal (O→T) and rhombohedral → orthorhombic (R→O) phase transitions were observed when the Ca content is at x = 0.05. Further increasing the Ca content, the DPT behavior gradually enhanced, and both the O→T and R→O phase transitions gradually evolved into R→T phase transition when the Ca content increases up to 0.15 at 25 °C. This behavior was related with phase structure and morphology, which significantly impacted the ferroelectric and piezoelectric properties near the R→T phase boundary. As a result, the sample with Ca contents of 0.15 shows the outstanding piezoelectric properties (with d33 = 572 pC/N, kp = 57%, Qm = 125, ɛr = 4821, and tan δ = 0.015) while negligible change for the ferroelectric properties. The abnormal ferroelectric behavior and potential factor contributing to large piezoelectric response also were discussed.

  1. Development of a Lead-free Piezoelectric (K,Na)NbO3 Thin Film Deposited on Nickel-based Electrodes

    NASA Astrophysics Data System (ADS)

    Bani Milhim, Alaeddin

    It is desirable to replace noble metals used as electrode materials for piezoelectric thin film with base metals. This will reduce the piezoelectric thin film fabrication cost. A nickel?based layer in conjunction with other protective layers is proposed as a bottom electrode for lead-free piezoelectric KNN thin film. The obtained results do not indicate the oxidation of the nickel?based bottom electrode after the deposition of KNN at 600 °C for 10 hours in the presence of oxygen and/or after annealing the sample at 400 °C for an hour in air. The fabricated KNN thin film was fully characterized in this work. The effective piezoelectric coefficients d33 and d31 were estimated to be 37 pm/V and 17.2 pm/V, respectively, at 100 kV/cm. The piezoelectric properties of the fabricated KNN/Ni/Ti/SiO2/Si are affected by the crystal orientation of the KNN layer, which was preferentially oriented in the (110) direction. Optimization of the deposition parameters of the fabricated KNN/Ni/Ti/SiO2/Si film is expected to further enhance the piezoelectric properties. Two novel systems utilizing the developed KNN piezoelectric thin film are proposed and their performance simulated based on the achieved KNN thin film parameters. The first is a precision automated nanomanipulation system using an AFM as a sensor and piezo-actuated manipulators. Real-time feedback of the particle being manipulated can be achieved using the proposed system. The length of the manipulators needs to be at least 2 mm to be incorporated with a commercial AFM system. To fabricate the required manipulators, a three-step electrochemical etching technique was developed. Tungsten tips combining well-defined conical shape, a length as large as 2 mm, and sharpness with a radius of curvature of around 20 nm were fabricated using the proposed technique. By depositing the KNN thin film on the fabricated manipulator, nanomanipulators with out-of-plane actuation can be produced. Ultrasonic piezoelectric fan array, the

  2. Pairing High Piezoelectric Coefficients, d33, with High Curie Temperature (TC) in Lead-Free (K,Na)NbO3.

    PubMed

    Rafiq, Muhammad Asif; Costa, Maria Elisabete; Vilarinho, Paula Maria

    2016-12-14

    The largest piezoelectric properties, d33 = 416 pC/N and 490 pC/N, in KxNa1-xNbO3 ceramics have been reported for compositions close to polymorphic phase transition (PPT); however, they also have Curie temperatures, TC, of around 217-304 °C, considerably lower than those of undoped KNN ceramics (420 °C). High d33 along with high TC remains the ideal choice for applications but, unfortunately, not attained up to now. Here, we show that using KNN single crystals as seeds for template grain growth (TGG) of KNN ceramics enables dramatic improvements in the electromechanical properties while maintaining a high TC. The (001)-oriented (K0.5Na0.5)0.98Li0.02NbO3 ceramics engineered by TGG using (K0.5Na0.5)NbO3 crystals as templates exhibit a high d33 of 280 pC/N while maintaining the high TC of 430 °C. Enhanced piezoelectricity is attributed to long-range ordered ferroelectric domain patterns consisting of 90° and 180° domains, similar to single crystals. It is the first time that pairing high d33 and high TC in KNN, keeping a high PPT temperature, is achieved. This study is an unequivocal proof that it is possible to maximize d33, keeping a high TC in KNN without resorting to heavily doped compositions. This work opens the door to high-performance, rare-earth free, compositionally simple lead-free and low-cost electromechanical compounds, which can largely expand lead-free piezoelectrics applications.

  3. Lead-Free Piezoelectric (Ba,Ca)(Zr,Ti)O3 Thin Films for Biocompatible and Flexible Devices.

    PubMed

    Scarisoreanu, N D; Craciun, F; Ion, V; Birjega, R; Bercea, A; Dinca, V; Dinescu, M; Sima, L E; Icriverzi, M; Roseanu, A; Gruionu, L; Gruionu, G

    2017-01-11

    In this work, we report the synthesis of functional biocompatible piezoelectric (1 - x)Ba(Ti0.8Zr0.2)TiO3-x(Ba0.7Ca0.3)TiO3, x = 0.45 (BCZT45), thin films with high piezoelectric properties. Pulsed-laser-based techniques, classical pulsed-laser deposition and matrix-assisted pulsed-laser evaporation, were used to synthesize the BCZT45 thin films. The second technique was employed in order to ensure growth on polymer flexible Kapton substrates. The BCZT45 thin films grown by both techniques show similar structural properties and high piezoelectric coefficient coupling between the mechanical loading and electrical potential. While it has long been shown that the electrical potential favors biological processes like osteogenesis, the assessment of cell adhesion and osteogenic differentiation onto BCZT materials has not yet been demonstrated. We prove here for the first time that BCZT 45 coatings on Kapton polymer substrates provide optimal support for osteogenic differentiation of mesenchymal stem cells in the bone marrow.

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

    NASA Astrophysics Data System (ADS)

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

    2005-04-01

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

  5. Properties of Miniature Cantilever-Type Ultrasonic Motor Using Lead-Free Array-Type Multilayer Piezoelectric Ceramics of (Sr,Ca)2NaNb5O15 under High Input Power

    NASA Astrophysics Data System (ADS)

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

    2012-07-01

    The properties of miniature cantilever-type ultrasonic motors using lead-free array-type multilayer piezoelectric ceramics of (Sr,Ca)2NaNb5O15 (SCNN) developed using the design rule were investigated under high input power by comparison with the high-power properties of SCNN ceramics. The frequency dependence of the revolution speed reflected the nonlinear behavior of SCNN ceramics with the hard-spring effect and showed a mirror-reversed image relative to that of the motor of Pb(Zr,Ti)O3 (PZT) ceramics. The output power increased linearly with increasing input power up to 110 mW without heat generation, and the driving properties were almost the same as the expectations under low input power. The output power density characteristics of the motors were high in comparison with those of the commercialized motors of PZT ceramics. It appeared that the motors have a high potential as an environmental friendly piezoelectric device with excellent properties, reflecting the high-power properties of SCNN ceramics.

  6. Relaxor ferroelectricity and electric-field-driven structural transformation in the giant lead-free piezoelectric (Ba ,Ca ) (Ti ,Zr ) O3

    NASA Astrophysics Data System (ADS)

    Brajesh, Kumar; Tanwar, Khagesh; Abebe, Mulualem; Ranjan, Rajeev

    2015-12-01

    There is great interest in lead-free (B a0.85C a0.15 ) (T i0.90Z r0.10 ) O3 (15/10BCTZ) because of its exceptionally large piezoelectric response [Liu and Ren, Phys. Rev. Lett. 103, 257602 (2009), 10.1103/PhysRevLett.103.257602]. In this paper, we have analyzed the nature of: (i) crystallographic phase coexistence at room temperature, (ii) temperature- and field-induced phase transformation to throw light on the atomistic mechanisms associated with the large piezoelectric response of this system. A detailed temperature-dependent dielectric and lattice thermal expansion study proved that the system exhibits a weak dielectric relaxation, characteristic of a relaxor ferroelectric material on the verge of exhibiting a normal ferroelectric-paraelectric transformation. Careful structural analysis revealed that a ferroelectric state at room temperature is composed of three phase coexistences, tetragonal (P 4 m m )+ orthorhombic(Amm 2 )+rhombohedral(R 3 m ) . We also demonstrate that the giant piezoresponse is associated with a significant fraction of the tetragonal phase transforming to rhombohedral. It is argued that the polar nanoregions associated with relaxor ferroelectricity amplify the piezoresponse by providing an additional degree of intrinsic structural inhomogeneity to the system.

  7. Origin of giant piezoelectric effect in lead-free K1−xNaxTa1−yNbyO3 single crystals

    PubMed Central

    Tian, Hao; Meng, Xiangda; Hu, Chengpeng; Tan, Peng; Cao, Xilong; Shi, Guang; Zhou, Zhongxiang; Zhang, Rui

    2016-01-01

    A series of high-quality, large-sized (maximum size of 16 × 16 × 32 mm3) K1−xNaxTa1−yNbyO3 (x = 0.61, 0.64, and 0.70 and corresponding y = 0.58, 0.60, and 0.63) single crystals were grown using the top-seed solution growth method. The segregation of the crystals, which allowed for precise control of the individual components of the crystals during growth, was investigated. The obtained crystals exhibited excellent properties without being annealed, including a low dielectric loss (0.006), a saturated hysteresis loop, a giant piezoelectric coefficient d33 (d33 = 416 pC/N, determined by the resonance method and d33* = 480 pC/N, measured using a piezo-d33 meter), and a large electromechanical coupling factor, k33 (k33 = 83.6%), which was comparable to that of lead zirconate titanate. The reason the piezoelectric coefficient d33 of K0.39Na0.61Ta0.42Nb0.58O3 was larger than those of the other two crystals grown was elucidated through first-principles calculations. The obtained results indicated that K1−xNaxTa1−yNbyO3 crystals can be used as a high-quality, lead-free piezoelectric material. PMID:27160075

  8. Origin of giant piezoelectric effect in lead-free K1-xNaxTa1-yNbyO3 single crystals.

    PubMed

    Tian, Hao; Meng, Xiangda; Hu, Chengpeng; Tan, Peng; Cao, Xilong; Shi, Guang; Zhou, Zhongxiang; Zhang, Rui

    2016-05-10

    A series of high-quality, large-sized (maximum size of 16 × 16 × 32 mm(3)) K1-xNaxTa1-yNbyO3 (x = 0.61, 0.64, and 0.70 and corresponding y = 0.58, 0.60, and 0.63) single crystals were grown using the top-seed solution growth method. The segregation of the crystals, which allowed for precise control of the individual components of the crystals during growth, was investigated. The obtained crystals exhibited excellent properties without being annealed, including a low dielectric loss (0.006), a saturated hysteresis loop, a giant piezoelectric coefficient d33 (d33 = 416 pC/N, determined by the resonance method and d33(*) = 480 pC/N, measured using a piezo-d33 meter), and a large electromechanical coupling factor, k33 (k33 = 83.6%), which was comparable to that of lead zirconate titanate. The reason the piezoelectric coefficient d33 of K0.39Na0.61Ta0.42Nb0.58O3 was larger than those of the other two crystals grown was elucidated through first-principles calculations. The obtained results indicated that K1-xNaxTa1-yNbyO3 crystals can be used as a high-quality, lead-free piezoelectric material.

  9. Origin of giant piezoelectric effect in lead-free K1‑xNaxTa1‑yNbyO3 single crystals

    NASA Astrophysics Data System (ADS)

    Tian, Hao; Meng, Xiangda; Hu, Chengpeng; Tan, Peng; Cao, Xilong; Shi, Guang; Zhou, Zhongxiang; Zhang, Rui

    2016-05-01

    A series of high-quality, large-sized (maximum size of 16 × 16 × 32 mm3) K1‑xNaxTa1‑yNbyO3 (x = 0.61, 0.64, and 0.70 and corresponding y = 0.58, 0.60, and 0.63) single crystals were grown using the top-seed solution growth method. The segregation of the crystals, which allowed for precise control of the individual components of the crystals during growth, was investigated. The obtained crystals exhibited excellent properties without being annealed, including a low dielectric loss (0.006), a saturated hysteresis loop, a giant piezoelectric coefficient d33 (d33 = 416 pC/N, determined by the resonance method and d33* = 480 pC/N, measured using a piezo-d33 meter), and a large electromechanical coupling factor, k33 (k33 = 83.6%), which was comparable to that of lead zirconate titanate. The reason the piezoelectric coefficient d33 of K0.39Na0.61Ta0.42Nb0.58O3 was larger than those of the other two crystals grown was elucidated through first-principles calculations. The obtained results indicated that K1‑xNaxTa1‑yNbyO3 crystals can be used as a high-quality, lead-free piezoelectric material.

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

    NASA Astrophysics Data System (ADS)

    Hosono, Yasuharu; Harada, Kouichi; Yamashita, Yohachi

    2001-09-01

    Single crystals of lead-free piezoelectric material x(Na1/2Bi1/2)TiO3-yBaTiO3 (NBBT 100x/100y) have been successfully grown by the flux method and the Bridgman method. Using the flux method, crystals having an edge length of 2-8 mm were obtained using Bi2O3 flux with cooling from 1350°C to 800°C at a rate of 3.5°C/h. Using the Bridgman method, comparatively good crystal of 15 mm diameter and 50 mm length was obtained using Bi2O3 flux with the Pt crucible driven down through the heat zone at a speed of 1.0 mm/h. The resulting crystals showed single-phase perovskite structure. Inductively charged plasma (ICP) chemical analysis revealed that the composition of the pulverized powder of these crystals is NBBT 97/3, which is slightly different from the charged composition of NBBT 94/6. One of the single crystals grown by the Bridgman method showed a dielectric constant of 1230 at room temperature and a dielectric constant peak at 313°C.

  11. Phase transition and electrical properties of (K0.5Na0.5)(Nb1-xTax)O3 lead-free piezoelectric ceramics

    NASA Astrophysics Data System (ADS)

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

    2008-04-01

    (K0.5Na0.5)(Nb1-xTax)O3 lead-free piezoelectric ceramics have been prepared by an ordinary sintering technique. The results of X-ray diffraction reveal that Ta5+ diffuses into the K0.5Na0.5NbO3 lattices to form a solid solution with an orthorhombic perovskite structure. Because of the high melting temperature of KTaO3, the (K0.5Na0.5)(Nb1-xTax)O3 ceramics can be sintered at higher temperatures. The partial substitution of Ta5+ for the B-site ion Nb5+ decreases both paraelectric/cubic ferroelectric/tetragonal and ferroelectric/tetragonal ferroelectric/orthorhombic phase transition temperatures, TC and TO-T. It also induces a relaxor phase transition and weakens the ferroelectricity of the ceramics. The ceramics become ‘softened’, leading to improvements in d33, kp, kt and ɛr and a decease in Ec, Qm and Np. The ceramics with x=0.075 0.15 become optimum, having d33=127 151 pC/N, kp=0.43 0.44, kt=0.43 0.44, ɛr=541 712, tanδ=1.75 2.48% and TC=378 329 °C.

  12. Flexible High-Performance Lead-Free Na0.47K0.47Li0.06NbO3 Microcube-Structure-Based Piezoelectric Energy Harvester.

    PubMed

    Gupta, Manoj Kumar; Kim, Sang-Woo; Kumar, Binay

    2016-01-27

    Lead-free piezoelectric nano- and microstructure-based generators have recently attracted much attention due to the continuous demand of self-powered body implantable devices. We report the fabrication of a high-performance flexible piezoelectric microgenerator based on lead-free inorganic piezoelectric Na0.47K0.47Li0.06NbO3 (NKLN) microcubes for the first time. The composite generator is fabricated using NKLN microcubes and polydimethylsiloxane (PDMS) polymer on a flexible substrate. The flexible device exhibits excellent performance with a large recordable piezoelectric output voltage of 48 V and output current density of 0.43 μA/cm(2) under vertical compressive force of 2 kgf, for which an energy conversion efficiency of about 11% has been achieved. Piezoresponse and ferroelectric studies reveal that NKLN microcubes exhibited high piezoelectric charge coefficient (d33) as high as 460 pC/N and a well-defined hysteresis loops with remnant polarization and coercive field of 13.66 μC/cm(2) and 19.45 kV/cm, respectively. The piezoelectric charge generation mechanism from NKLN microgenerator are discussed in the light of the high d33 and alignment of electric dipoles in polymer matrix and dielectric constant of NKLN microcubes. It has been demonstrated that the developed power generator has the potential to generate high electric output power under mechanical vibration for powering biomedical devices in the near future.

  13. Crystal structure and phase transition behavior in (K1-xNax)NbO3-based lead-free piezoelectric ceramic over a wide range of temperatures

    NASA Astrophysics Data System (ADS)

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

    2016-12-01

    The phase transition temperature in a (K, Na)NbO3 (KNN) phase of a KNN-based composite lead-free piezoelectric ceramic with a KTiNbO5 system ((K1-xNax)0.86Ca0.04Li0.02Nb0.85O3-δ-K0.85Ti0.85Nb1.15O5-BaZrO3-Co3O4-Fe2O3-ZnO) is lower than that in an undoped KNN ceramic by approximately 200 °C. We have studied the structural changes around the phase transition by using synchrotron powder X-ray diffraction and transmission electron microscopy. The crystal system of the main KNN phase is assigned to tetragonal as a stable structure at room temperature and does not change to orthorhombic on lowering the temperature all at once. The crystal structure changes from tetragonal to orthorhombic through the successive transition state. The curve of the phase transition temperature from x = 0.33 to 0.75 has a V shape and reaches its lowest value of approximately 0 °C in the vicinity of x = 0.56. From selected-area electron diffraction patterns of the KNN phase, weak superlattice spots owing to the tilt-ordered NbO6 octahedra are observed for x ≥ 0.56. This tilt-ordered NbO6 octahedral phase is formed at the nanometer-scale (nanodomains) in the tetragonal and orthorhombic KNN matrices, regardless of the phase transition. The minimum x to generate the nanodomains is substantially equal to the Na fraction at which the starting temperature of the successive phase transition shifts to the lowest.

  14. Flexible energy harvesting from hard piezoelectric beams

    NASA Astrophysics Data System (ADS)

    Delnavaz, Aidin; Voix, Jérémie

    2016-11-01

    This paper presents design, multiphysics finite element modeling and experimental validation of a new miniaturized PZT generator that integrates a bulk piezoelectric ceramic onto a flexible platform for energy harvesting from the human body pressing force. In spite of its flexibility, the mechanical structure of the proposed device is simple to fabricate and efficient for the energy conversion. The finite element model involves both mechanical and piezoelectric parts of the device coupled with the electrical circuit model. The energy harvester prototype was fabricated and tested under the low frequency periodic pressing force during 10 seconds. The experimental results show that several nano joules of electrical energy is stored in a capacitor that is quite significant given the size of the device. The finite element model is validated by observing a good agreement between experimental and simulation results. the validated model could be used for optimizing the device for energy harvesting from earcanal deformations.

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

    NASA Astrophysics Data System (ADS)

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

    2012-09-01

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

  16. Giant strain with ultra-low hysteresis and high temperature stability in grain oriented lead-free K₀̣₅Bi₀̣₅TiO₃-BaTiO₃-Na₀̣₅Bi₀̣₅TiO₃ piezoelectric materials

    DOE PAGES

    Maurya, Deepam; Zhou, Yuan; Wang, Yaojin; ...

    2015-02-26

    We synthesized grain-oriented lead-free piezoelectric materials in (K₀̣₅Bi₀̣₅TiO₃-BaTiO₃-xNa₀̣₅Bi₀̣₅TiO₃ (KBT-BT-NBT) system with high degree of texturing along the [001]c (c-cubic) crystallographic orientation. We demonstrate giant field induced strain (~0.48%) with an ultra-low hysteresis along with enhanced piezoelectric response (d₃₃ ~ 190pC/N) and high temperature stability (~160°C). Transmission electron microscopy (TEM) and piezoresponse force microscopy (PFM) results demonstrate smaller size highly ordered domain structure in grain-oriented specimen relative to the conventional polycrystalline ceramics. The grain oriented specimens exhibited a high degree of non-180° domain switching, in comparison to the randomly axed ones. These results indicate the effective solution to the lead-free piezoelectricmore » materials.« less

  17. Correlation between microstructure and hardness of a Bi-1.5wt%Ag lead-free solder alloy

    NASA Astrophysics Data System (ADS)

    Spinelli, J. E.; Macedo, R. A.; Silva, B. L.; Garcia, A.

    2016-03-01

    In the present study a hypoeutectic Bi-1.5wt%Ag alloy was directionally solidified under transient heat flow conditions and the microstructure was analysed. Bi-Ag alloys are considered as potential alternatives to replace Pb-based alloys as solder materials for metallic connections under high temperatures. However, a lack of understanding regarding the effects of solidification thermal parameters (growth rate - VL, the cooling rate - Ṫ) on microstructural aspects is reported in literature. Another challenge is to improve properties and reliability. The results of the present study include the determination of the tip growth rate and the cooling rate by cooling curves recorded by thermocouples positioned along the casting length, metallography, X-ray fluorescence (XRF) and Vickers hardness. The entire directionally solidified Bi-1.5Ag microstructure was arranged by faceted Bi-rich dendrites surrounded by a eutectic mixture (Bi+Ag). The primary and secondary dendrite arm spacing (λ1 and λ2), the interphase spacing (λ) and the diameter of Ag-rich particles were also measured along the casting length; and experimental growth laws. Relating these microstructural features to the experimental thermal parameters are proposed.

  18. Effects of K content on the dielectric, piezoelectric, and ferroelectric properties of 0.95(KxNa1-x)NbO3-0.05LiSbO3 lead-free ceramics

    NASA Astrophysics Data System (ADS)

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

    2008-01-01

    The effects of K content on the dielectric, piezoelectric, and ferroelectric properties of 0.95(KxNa1-x)NbO3-0.05LiSbO3 (0.95KxNN-0.05LS) (x =0.25-0.75) lead-free piezoelectric ceramics prepared by conventional solid-state sintering were studied. The experimental results show that the dielectric, piezoelectric, and ferroelectric properties strongly depend on K content in the 0.95KxNN-0.05LS ceramics. The 0.95KxNN-0.05LS (x =0.40) ceramics exhibit enhanced electrical properties (d33≈280 pC/N; kp≈49.4%; Tc˜364 °C; To-t=25 °C; ɛr≈1463; tan δ ≈2.3%; Pr˜30.8 μC/cm2; Ec˜14.0 kV/cm). The enhanced electrical properties of 0.95KxNN-0.05LS (x =0.40) ceramics are attributed to the polymorphic phase transition near room temperature. These results show that 0.95KxNN-0.05LS (x =0.40) ceramic is a promising lead-free piezoelectric material.

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

    SciTech Connect

    Wei, Yongbin; Jia, Yanmin E-mail: ymjia@zjnu.edu.cn; Wu, Jiang; Shen, Yichao; Wu, Zheng E-mail: ymjia@zjnu.edu.cn; Luo, Haosu

    2014-07-28

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

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

    SciTech Connect

    Yu, Qi; Zhu, Fang-Yuan; Cheng, Li-Qian; Wang, Ke; Li, Jing-Feng

    2014-03-10

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

  1. FAST TRACK COMMUNICATION: Phase structure and electrical properties of K0.5Na0.5(Nb0.94Sb0.06)O3-LiTaO3 lead-free piezoelectric ceramics

    NASA Astrophysics Data System (ADS)

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

    2008-03-01

    Lead-free piezoelectric ceramics (1-x)K0.5Na0.5(Nb0.94Sb0.06)O3-xLiTaO3 have been fabricated by a conventional solid-state sintering technique. The ceramics can be well sintered at 1080-1110 °C and exhibit a dense, single-phase perovskite structure at x <= 0.06. Coexistence of the tetragonal and orthorhombic phases is formed in the ceramics with 0.02 < x < 0.05, leading to a significant enhancement in piezoelectric properties. For the ceramic with x = 0.04, the piezoelectric properties become optimum: piezoelectric constant d33 = 271 pC N-1, electromechanical coupling coefficients kP = 0.53 and kt = 0.43. Moreover, the ceramics are non-deliquescent and exhibit excellent performance in transducer applications, indicating that the ceramics are ready for replacing lead-containing ceramics in practical applications.

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

    NASA Astrophysics Data System (ADS)

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

    2012-09-01

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

  3. 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)

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

    2013-08-01

    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 μC/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 (ɛ'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.

  4. Thermally stable electrostrains of morphotropic 0.875NaNbO3-0.1BaTiO3-0.025CaZrO3 lead-free piezoelectric ceramics

    NASA Astrophysics Data System (ADS)

    Qi, He; Zuo, Ruzhong; Fu, Jian; Dou, Mengxian

    2017-03-01

    The 0.875NaNbO3-0.1BaTiO3-0.025CaZrO3 relaxor ferroelectric ceramics were reported to exhibit thermally stable electrostrains (˜0.15% @ 6 kV/mm) from room temperature (RT) to ˜175 °C and comparable strain hysteresis (<13%) to that of typical lead-based piezoelectric ceramics. Dominant strain contribution mechanisms with increasing temperature were analyzed by means of temperature-dependent permittivity, polarization, and strain measurements and synchrotron x-ray diffraction. The rhombohedral (R) and tetragonal (T) morphotropic phase boundary provided a solid structural base for temperature-stable piezoelectric strains from RT to ˜140 °C. The growth of polar nanoregions (pseudocubic) into microdomains (R) and subsequent field-induced R-T phase transition, as well as large electrostrictive effects, sequentially contributed to high electrostrain levels in the proximity of the Curie temperature (from 140 to 175 °C). In addition, the observed low strain hysteresis was attributed to the small strain fraction from domain switching. These experimental results demonstrated that NaNbO3-based relaxor ferroelectrics might be potential lead-free materials for actuator applications.

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

    PubMed Central

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

    2015-01-01

    We synthesized grain-oriented lead-free piezoelectric materials in (K0.5Bi0.5TiO3-BaTiO3-xNa0.5Bi0.5TiO3 (KBT-BT-NBT) system with high degree of texturing along the [001]c (c-cubic) crystallographic orientation. We demonstrate giant field induced strain (~0.48%) with an ultra-low hysteresis along with enhanced piezoelectric response (d33 ~ 190pC/N) and high temperature stability (~160°C). Transmission electron microscopy (TEM) and piezoresponse force microscopy (PFM) results demonstrate smaller size highly ordered domain structure in grain-oriented specimen relative to the conventional polycrystalline ceramics. The grain oriented specimens exhibited a high degree of non-180° domain switching, in comparison to the randomly axed ones. These results indicate the effective solution to the lead-free piezoelectric materials. PMID:25716551

  6. Giant strain with ultra-low hysteresis and high temperature stability in grain oriented lead-free K₀̣₅Bi₀̣₅TiO₃-BaTiO₃-Na₀̣₅Bi₀̣₅TiO₃ piezoelectric materials

    SciTech Connect

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

    2015-02-26

    We synthesized grain-oriented lead-free piezoelectric materials in (K₀̣₅Bi₀̣₅TiO₃-BaTiO₃-xNa₀̣₅Bi₀̣₅TiO₃ (KBT-BT-NBT) system with high degree of texturing along the [001]c (c-cubic) crystallographic orientation. We demonstrate giant field induced strain (~0.48%) with an ultra-low hysteresis along with enhanced piezoelectric response (d₃₃ ~ 190pC/N) and high temperature stability (~160°C). Transmission electron microscopy (TEM) and piezoresponse force microscopy (PFM) results demonstrate smaller size highly ordered domain structure in grain-oriented specimen relative to the conventional polycrystalline ceramics. The grain oriented specimens exhibited a high degree of non-180° domain switching, in comparison to the randomly axed ones. These results indicate the effective solution to the lead-free piezoelectric materials.

  7. Dielectric and piezoelectric properties of lead-free 0.5Ba(Zr0.2 Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 piezoelectric ceramics with glass additive.

    PubMed

    Im, In-Ho; Chung, Kwang-Hyun

    2014-12-01

    We have investigated the dielectric and piezoelectric properties of lead-free 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 ceramics with BaO-CaO-SiO2 glass additive as a function of sintering temperatures. With adding BaO-CaO-SiO2 glass additive, diffusivity of lead-free 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 ceramics was increased. The dispersion constant γ of BZT-BCT ceramics with BaO-CaO-SiO2 glass was changed from 1.9683 to 1.7673 by decreasing sintering temperature ranging from 1450 degrees C to 1350 degrees C, while 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 ceramics at sintered 1450 degrees C showed γ = 1.5055. The piezoelectric properties such as electromechanical coupling factor (k(p)) and piezoelectric constant (d33) of lead-free 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 ceramics with BaO-CaO-SiO2 glass additive sintered at 1400 degrees C showed similar values compared with 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 ceramics without BaO-CaO-SiO2 glass additive sintered at 1450 degrees C. The addition of BaO-CaO-SiO2 glass additive can be of help to decrease sintering temperature of lead-free 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 ceramics.

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

    NASA Astrophysics Data System (ADS)

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

    2013-09-01

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

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

    PubMed

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

    2004-11-01

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

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

    SciTech Connect

    Liu, Feng; Wahyudi, Olivia; Li, Yongxiang

    2014-03-21

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

  11. Improved Piezoelectricity in (K0.44Na0.52Li0.04) (Nb0.91Ta0.05Sb0.04)O3- xBi0.25Na0.25NbO3 Lead-Free Piezoelectric Ceramics

    NASA Astrophysics Data System (ADS)

    Zhao, Yan; Xu, Zhijun; Li, Huaiyong; Hao, Jigong; Du, Juan; Chu, Ruiqing; Wei, Dongdong; Li, Guorong

    2017-01-01

    (1 - x)[(K0.44Na0.52Li0.04)(Nb0.91Ta0.05Sb0.04)O3]- xBi0.25Na0.25NbO3 (KNLNTS- xBNN) lead-free piezoelectric ceramics have been prepared using a conventional solid-state reaction method and the effects of BNN on their phase structure, microstructure, and electrical properties systematically studied. X-ray diffraction analysis suggested that BNN substitution into KNLNTS induced coexistence of orthorhombic-tetragonal mixed phase and thus improved the ferroelectric and piezoelectric properties. The surface morphologies indicated that different amounts of BNN had two different effects on grain growth. Good electrical properties ( d 33 = 256 pC N-1, T c = 354.27°C, k p = 43.43%, P r = 26.85 μC cm-2, E c = 24.47 kV cm-1) were simultaneously obtained at x = 0.0025, suggesting that our research could benefit development of (K,Na)NbO3-based ceramics and widen their application range.

  12. Active-passive hybrid piezoelectric actuators for high-precision hard disk drive servo systems

    NASA Astrophysics Data System (ADS)

    Chan, Kwong Wah; Liao, Wei-Hsin

    2006-03-01

    Positioning precision is crucial to today's increasingly high-speed, high-capacity, high data density, and miniaturized hard disk drives (HDDs). The demand for higher bandwidth servo systems that can quickly and precisely position the read/write head on a high track density becomes more pressing. Recently, the idea of applying dual-stage actuators to track servo systems has been studied. The push-pull piezoelectric actuated devices have been developed as micro actuators for fine and fast positioning, while the voice coil motor functions as a large but coarse seeking. However, the current dual-stage actuator design uses piezoelectric patches only without passive damping. In this paper, we propose a dual-stage servo system using enhanced active-passive hybrid piezoelectric actuators. The proposed actuators will improve the existing dual-stage actuators for higher precision and shock resistance, due to the incorporation of passive damping in the design. We aim to develop this hybrid servo system not only to increase speed of track seeking but also to improve precision of track following servos in HDDs. New piezoelectrically actuated suspensions with passive damping have been designed and fabricated. In order to evaluate positioning and track following performances for the dual-stage track servo systems, experimental efforts are carried out to implement the synthesized active-passive suspension structure with enhanced piezoelectric actuators using a composite nonlinear feedback controller.

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

    SciTech Connect

    Jaita, Pharatree; Watcharapasorn, Anucha; Jiansirisomboon, Sukanda

    2013-07-14

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

  14. Enhanced temperature stability and quality factor with Hf substitution for Sn and MnO2 doping of (Ba0.97Ca0.03)(Ti0.96Sn0.04)O3 lead-free piezoelectric ceramics with high Curie temperature

    NASA Astrophysics Data System (ADS)

    Tsai, Cheng-Che; Chao, Wei-Hsiang; Chu, Sheng-Yuan; Hong, Cheng-Shong; Weng, Chung-Ming; Su, Hsiu-Hsien

    2016-12-01

    In this work, the process of two-stage modifications for (Ba0.97Ca0.03)(Ti0.96Sn0.04-xHfx)O3 (BCTS4-100xH100x) ceramics was studied. The trade-off composition was obtained by Hf substitution for Sn and MnO2 doping (two-stage modification) which improves the temperature stability and piezoelectric properties. The phase structure ratio, microstructure, and dielectric, piezoelectric, ferroelectric, and temperature stability properties were systematically investigated. Results showed that BCTS4-100xH100x piezoelectric ceramics with x=0.035 had a relatively high Curie temperature (TC) of about 112 °C, a piezoelectric charge constant (d33) of 313 pC/N, an electromechanical coupling factor (kp) of 0.49, a mechanical quality factor (Qm) of 122, and a remnant polarization (Pr) of 19 μ C /cm2 . In addition, the temperature stability of the resonant frequency (fr), kp, and aging d33 could be tuned via Hf content. Good piezoelectric temperature stability (up to 110 °C) was found with x =0.035. BCTS0.5H3.5 + a mol% Mn (BCTSH + a Mn) piezoelectric ceramics with a = 2 had a high TC of about 123 °C, kp ˜ 0.39, d33 ˜ 230 pC/N, Qm ˜ 341, and high temperature stability due to the produced oxygen vacancies. This mechanism can be depicted using the complex impedance analysis associated with a valence compensation model on electric properties. Two-stage modification for lead-free (Ba0.97Ca0.03)(Ti0.96Sn0.04)O3 ceramics suitably adjusts the compositions for applications in piezoelectric motors and actuators.

  15. Bright reddish-orange emission and good piezoelectric properties of Sm{sub 2}O{sub 3}-modified (K{sub 0.5}Na{sub 0.5})NbO{sub 3}-based lead-free piezoelectric ceramics

    SciTech Connect

    Hao, Jigong; Xu, Zhijun Chu, Ruiqing; Li, Wei; Du, Juan

    2015-05-21

    Reddish orange-emitting 0.948(K{sub 0.5}Na{sub 0.5})NbO{sub 3}-0.052LiSbO{sub 3}-xmol%Sm{sub 2}O{sub 3} (KNN-5.2LS-xSm{sub 2}O{sub 3}) lead-free piezoelectric ceramics with good piezoelectric properties were fabricated in this study, and the photoluminescence and electrical properties of the ceramics were systematically studied. Results showed that Sm{sub 2}O{sub 3} substitution into KNN-5.2LS induces a phase transition from the coexistence of orthorhombic and tetragonal phases to a pseudocubic phase and shifts the polymorphic phase transition (PPT) to below room temperature. The temperature stability and fatigue resistance of the modified ceramics were significantly improved by Sm{sub 2}O{sub 3} substitution. The KNN-5.2LS ceramic with 0.4 mol. % Sm{sub 2}O{sub 3} exhibited temperature-independent properties (25–150 °C), fatigue-free behavior (up to 10{sup 6} cycles), and good piezoelectric properties (d{sub 33}{sup * }= 230 pm/V, d{sub 33} = 176 pC/N, k{sub p} = 35%). Studies on the photoluminescence properties of the samples showed strong reddish-orange emission upon blue light excitation; these emission intensities were strongly dependent on the doping concentration and sintering temperature. The 0.4 mol. % Sm{sub 2}O{sub 3}-modified sample exhibited temperature responses over a wide temperature range of 10–443 K. The maximum sensing sensitivity of the sample was 7.5 × 10{sup −4} K at 293 K, at which point PPT occurred. A relatively long decay lifetime τ of 1.27–1.40 ms and a large quantum yield η of 0.17–0.19 were obtained from the Sm-modified samples. These results suggest that the KNN-5.2LS-xSm{sub 2}O{sub 3} system presents multifunctional properties and significant technological potential in novel multifunctional devices.

  16. Nondestructive testing and hardness measurement based on contact resonance of piezoelectric cantilevers (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Li, Faxin; Fu, Ji

    2016-04-01

    A suitable defect identification parameter is very important in the field of nondestructive testing (NDT). In this work, we proposed a NDT method which detects the sample's local contact stiffness (LCS) based on the contact resonance of a piezoelectric cantilever. Firstly, through finite element analysis we showed that LCS is quite sensitive to typical defects including debonding, voids, cracks and inclusions, making it a good identification parameter. Secondly, a homemade NDT system containing a piezoelectric unimorph cantilever was assembled to detect the sample's LCS by tracking the contact resonance frequency (CRF) of the cantilever-sample system based on strain signals. Testing results indicated that this NDT system could detect the above mentioned defects efficiently. The cantilever-stiffness dependent detection sensitivity was specially investigated and the stiffer cantilevers were found to be more sensitive to small defects. Then, a piezoelectric bimorph cantilever was fabricated and the electromechanical impedance, other than the strain signals, was measured to track the CRF of the cantilever-system. The LCS is then derived by using the equivalent-circuit model. The electromechanical impedance based NDT system is more compact and can be further developed to be a portable device. Finally, a Vicker indenter is fabricated onto the bimorph tip and the contact area is derived from the measured LCS. Thus the NDT system turns to be a hardness tester without any optical devices. It is very useful for in-situ testing or testing on inner surfaces where conventional hardness tester is not applicable.

  17. Breakthrough: Lead-free Solder

    SciTech Connect

    Anderson, Iver

    2012-01-01

    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.

  18. Lead-free primary explosives

    DOEpatents

    Huynh, My Hang V.

    2010-06-22

    Lead-free primary explosives of the formula (cat).sub.Y[M.sup.II(T).sub.X(H.sub.2O).sub.6-X].sub.Z, where T is 5-nitrotetrazolate, and syntheses thereof are described. Substantially stoichiometric equivalents of the reactants lead to high yields of pure compositions thereby avoiding dangerous purification steps.

  19. Breakthrough: Lead-free Solder

    ScienceCinema

    Anderson, Iver

    2016-07-12

    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.

  20. Strong piezoelectricity in (1 - x)(K0.4Na0.6)(Nb0.96Sb0.04)O3-xBi0.5K0.5Zr1-ySnyO3 lead-free binary system: identification and role of multiphase coexistence.

    PubMed

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

    2015-03-18

    Here we report a strong piezoelectric activity in (1 - x)(K0.4Na0.6)(Nb0.96Sb0.04)O3-xBi0.5K0.5Zr1-ySnyO3 lead-free ceramics by designing different phase boundaries. The phase boundaries concerning rhombohedral-orthorhombic-tetragonal (R-O-T) and rhombohedral-tetragonal (R-T) multiphase coexistence were attained by changing BKZS and Sn contents and then were identified by the X-ray diffraction patterns as well as temperature-dependent permittivity and ν1 Raman modes associated with BO6 perovskite octahedron. A high strain (strain = 0.21-0.28% and d33* = 707-880 pm/V) and a strong piezoelectric coefficient (d33 = 415-460 pC/N) were shown in the ceramics located at the multiphase coexistence region. The reported results of this work are superior to that (d33* ∼ 570 pm/V and d33 ∼ 416 pC/N) of the textured (K,Na,Li)(Nb,Ta,Sb)O3 ceramics [Nature 2004, 432, 84]. We believe that the material system of this work will become one of the most promising candidates for piezoelectric actuators.

  1. Orientation-dependent piezoelectric properties in lead-free epitaxial 0.5BaZr0.2Ti0.8O3-0.5Ba0.7Ca0.3TiO3 thin films

    NASA Astrophysics Data System (ADS)

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

    2013-09-01

    Orientation-engineered 0.5BaZr0.2Ti0.8O3-0.5Ba0.7Ca0.3TiO3 (BZT-BCT) thin films were deposited on La0.7Sr0.3MnO3-coated SrTiO3 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 d33,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.

  2. 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

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

    2013-09-16

    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.

  3. Design and fabrication of a piezoelectric instrumented suspension for hard disk drives

    NASA Astrophysics Data System (ADS)

    Kon, Stanley; Oldham, Kenn; Ruzicka, Ryan; Horowitz, Roberto

    2006-03-01

    As data densities in computer hard disk drives increase, airflow-induced vibration of the disk drive suspension becomes a major barrier to positioning the read-write head with sufficient precision. One component in reducing these vibrations is a dedicated sensor system for detecting vibration on the sensor arm directly, which enables high-frequency sampling and modal selectivity. In this paper, an efficient method for identifying optimal position and shape of piezoelectric strain gages on a flexible structure is presented, and applied to the steel suspension of a hard disk drive. Zinc oxide deposition processes are adapted to steel substrates, and used to fabricate miniature zinc oxide strain gages at the optimal strain gage location. Substrates with sensors installed were assembled into full disk drive suspensions and tested in a commercial disk drive.

  4. A finger-like hardness tester based on the contact electromechanical impedance of a piezoelectric bimorph cantilever.

    PubMed

    Fu, Ji; Li, Faxin

    2015-10-01

    We proposed a finger-like hardness tester based on the electromechanical impedance of a piezoelectric bimorph cantilever. A Vickers indenter was fabricated to the free end of the bimorph to contact the sample. The contact force was monitored by a strain gauge and the contact area was obtained by tracking the bimorph's resonance frequency. The bimorph-sample contact system was modeled by the electromechanical equivalent circuit method. Verification experiments on standard hardness samples were conducted and the measured hardness values agreed well with those given by a conventional Vickers hardness tester. Further hardness measurement on a gear wheel showed that the proposed hardness tester is very adaptive and can be used for inner surface testing or in situ testing, where other hardness testers may not be applicable. The proposed hardness tester can be regarded as an improved ultrasonic hardness tester.

  5. Strong anisotropy of ferroelectricity in lead-free bismuth silicate

    NASA Astrophysics Data System (ADS)

    Seol, Daehee; Taniguchi, Hiroki; Hwang, Jae-Yeol; Itoh, Mitsuru; Shin, Hyunjung; Kim, Sung Wng; Kim, Yunseok

    2015-07-01

    Bismuth silicate (Bi2SiO5) was recently suggested as a potential silicate based lead-free ferroelectric material. Here, we show the existence of ferroelectricity and explore the strong anisotropy of local ferroelectricity using piezoresponse force microscopy (PFM). Domain structures are reconstructed using angle-resolved PFM. Furthermore, piezoresponse hysteresis loops and piezoelectric coefficients are spatially investigated at the nanoscale. The obtained results confirm the existence of ferroelectricity with strong c-axis polarization. These results could provide basic information on the anisotropic ferroelectricity in Bi2SiO5 and furthermore suggest its considerable potential for lead-free ferroelectric applications with silicon technologies.Bismuth silicate (Bi2SiO5) was recently suggested as a potential silicate based lead-free ferroelectric material. Here, we show the existence of ferroelectricity and explore the strong anisotropy of local ferroelectricity using piezoresponse force microscopy (PFM). Domain structures are reconstructed using angle-resolved PFM. Furthermore, piezoresponse hysteresis loops and piezoelectric coefficients are spatially investigated at the nanoscale. The obtained results confirm the existence of ferroelectricity with strong c-axis polarization. These results could provide basic information on the anisotropic ferroelectricity in Bi2SiO5 and furthermore suggest its considerable potential for lead-free ferroelectric applications with silicon technologies. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr03161c

  6. Piezoelectric Sensor to Measure Soft and Hard Stiffness with High Sensitivity for Ultrasonic Transducers.

    PubMed

    Li, Yan-Rui; Su, Chih-Chung; Lin, Wen-Jin; Chang, Shuo-Hung

    2015-06-11

    During dental sinus lift surgery, it is important to monitor the thickness of the remaining maxilla to avoid perforating the sinus membrane. Therefore, a sensor should be integrated into ultrasonic dental tools to prevent undesirable damage. This paper presents a piezoelectric (PZT) sensor installed in an ultrasonic transducer to measure the stiffness of high and low materials. Four design types using three PZT ring materials and a split PZT for actuator and sensor ring materials were studied. Three sensor locations were also examined. The voltage signals of the sensor and the displacement of the actuator were analyzed to distinguish the low and high stiffness. Using sensor type T1 made of the PZT-1 material and the front location A1 provided a high sensitivity of 2.47 Vm/kN. The experimental results demonstrated that our design can measure soft and hard stiffness.

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

    SciTech Connect

    Chen, Cheng-Sao; Chen, Pin-Yi; Tu, Chi-Shun

    2014-01-07

    A structural coexistence of rhombohedral (R) and tetragonal (T) phases has been revealed in the (001){sub c}-cut lead-free 0.93(Bi{sub 1/2}Na{sub 1/2})TiO{sub 3}–0.07BaTiO{sub 3} (BNB7T) piezoelectric crystals, which grown by the self-flux method, in the lower temperatures by high-resolution synchrotron X-ray diffraction, reciprocal space mapping, and transmission electron microscopy. The dielectric permittivity exhibits a thermal hysteresis in the region of 120–260 °C, implying a first-order-like phase transition from R+T to T. The real part (ε′) of dielectric permittivity begins to deviates from the Curie-Weiss equation, ε′ = C/(T − T{sub o}), from the Burns temperature T{sub B} = 460 °C, below which the polar nanoregions (or nanoclusters) develop and attenuate dielectric responses. The polar nanoregions of 5–10 nm were revealed by high-resolution transmission electron microscope. The normal piezoelectric coefficient d{sub 33} exhibits a rapid increase at E = 15–20 kV/cm and reaches a maximum of d{sub 33} ∼450 pC/N. The high piezoelectric response and E-field induced strain in BNB7T single crystals can be attributed to structural phase transitions under an E-field application.

  8. Domain wall motion and electromechanical strain in lead-free piezoelectrics: Insight from the model system (1 − x)Ba(Zr{sub 0.2}Ti{sub 0.8})O{sub 3}–x(Ba{sub 0.7}Ca{sub 0.3})TiO{sub 3} using in situ high-energy X-ray diffraction during application of electric fields

    SciTech Connect

    Tutuncu, Goknur; Li, Binzhi; Bowman, Keith; Jones, Jacob L.

    2014-04-14

    The piezoelectric compositions (1 − x)Ba(Zr{sub 0.2}Ti{sub 0.8})O{sub 3}–x(Ba{sub 0.7}Ca{sub 0.3})TiO{sub 3} (BZT-xBCT) span a model lead-free morphotropic phase boundary (MPB) between room temperature rhombohedral and tetragonal phases at approximately x = 0.5. In the present work, in situ X-ray diffraction measurements during electric field application are used to elucidate the origin of electromechanical strain in several compositions spanning the tetragonal compositional range 0.6 ≤ x ≤ 0.9. As BCT concentration decreases towards the MPB, the tetragonal distortion (given by c/a-1) decreases concomitantly with an increase in 90° domain wall motion. The increase in observed macroscopic strain is predominantly attributed to the increased contribution from 90° domain wall motion. The results demonstrate that domain wall motion is a significant factor in achieving high strain and piezoelectric coefficients in lead-free polycrystalline piezoelectrics.

  9. Domain wall motion and electromechanical strain in lead-free piezoelectrics: Insight from the model system (1 - x)Ba(Zr0.2Ti0.8)O3-x(Ba0.7Ca0.3)TiO3 using in situ high-energy X-ray diffraction during application of electric fields

    SciTech Connect

    Tutuncu, Goknur; Li, Binzhi; Bowman, Keith; Jones, Jacob L.

    2014-07-17

    The piezoelectric compositions (1 - x)Ba(Zr0.2Ti0.8)O3–x(Ba0.7Ca0.3)TiO3 (BZT-xBCT) span a model lead-free morphotropic phase boundary (MPB) between room temperature rhombohedral and tetragonal phases at approximately x = 0.5. In the present work, in situ X-ray diffraction measurements during electric field application are used to elucidate the origin of electromechanical strain in several compositions spanning the tetragonal compositional range 0.6 ≤ x ≤ 0.9. As BCT concentration decreases towards the MPB, the tetragonal distortion (given by c/a-1) decreases concomitantly with an increase in 90° domain wall motion. The increase in observed macroscopic strain is predominantly attributed to the increased contribution from 90° domain wall motion. The results demonstrate that domain wall motion is a significant factor in achieving high strain and piezoelectric coefficients in lead-free polycrystalline piezoelectrics.

  10. Large Field-Induced Strain Properties of Sr(K0.25Nb0.75) O3-Modified Bi1/2(Na0.82K0.18)1/2TiO3 Lead-Free Piezoelectric Ceramics

    NASA Astrophysics Data System (ADS)

    Tran, Vu Diem Ngoc; Ullah, Aman; Dinh, Thi Hinh; Lee, Jae-Shin

    2016-05-01

    Lead-free piezoelectric ceramics with compositions of (1 - x)Bi1/2(Na0.82 K0.18)1/2TiO3 + xSr(K0.25Nb0.75)O3, which are abbreviated as (1 - x)BNKT- xSKN with x = 0, 0.01, 0.02, 0.03, 0.04, and 0.05, were synthesized using a conventional solid-state reaction method. The effects of SKN addition on the BNKT system were examined in terms of the phase transition, strain behavior, and ferroelectric and dielectric properties. X-ray diffraction revealed a single perovskite phase for all compositions. The results showed that with increasing SKN content, BNKT-SKN underwent a phase transition from the coexistence of rhombohedral and tetragonal phases to a tetragonal phase. The addition of SKN shifted the depolarization temperature, T d, to a lower temperature and enhanced the diffuseness of the dielectric peaks. The polarization and bipolar strain hysteresis loops of BNKT-SKN showed that the addition of SKN induced a ferroelectric to ergodic relaxor phase transition with a disruption of the ferroelectric order of pure BNKT. As a result, the strain of BNKT-SKN improved significantly with increasing SKN content and reached the highest value of a normalized strain, S max/ E max, of 557 pm/V, when modified with 3 mol.% SKN.

  11. NASA DOD Lead Free Electronics Project

    NASA Technical Reports Server (NTRS)

    Kessel, Kurt R.

    2008-01-01

    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.

  12. Optimizing electrical poling for tetragonal, lead-free BZT-BCT piezoceramic alloys

    SciTech Connect

    Li, Binzhi; Ehmke, Matthias C.; Blendell, John E.; Bowman, Keith J.

    2014-02-13

    The piezoelectric properties of tetragonal BZT–BCT materials have been shown to be improved by using the field cooling poling method. It is shown that the piezoelectric coefficient of tetragonal BZT–BCT materials increases with higher poling temperature, and the optimum poling temperature lies near the Curie temperatures for a broad range of compositions. It is also observed from in situ X-ray diffraction measurements with an applied electric field that the magnitude of domain alignment is enhanced with electrical poling at higher electric fields, whereas the remnant ferroelastic domain texture is not affected. Furthermore, these results show a direct correlation between the development of internal bias field, which is induced by the accumulation of defect charge carriers, and the enhanced piezoelectric coefficient. These observations suggest an important role played by the alignment of defect charge carriers in achieving optimum piezoelectric coefficient in lead-free piezoelectric ceramics.

  13. Ferroelastic domains in lead-free barium zirconate titanate - barium calcium titanate piezoceramics

    NASA Astrophysics Data System (ADS)

    Ehmke, Matthias Claudius

    Piezoelectricity was first discovered by Pierre and Jaque Curie in the year 1880. Nowadays, piezoelectric materials are used in many application such as high voltage generation in gas igniters, actuation in micro-positioning devices, generation and detection of acoustic waves, emitters and receivers for sonar technology, ultrasonic cleaning, ultrasound medical therapy, and micropumps for ink-jet printers. The most commonly used piezoelectric material since the 1950's is the solid solution system lead zirconate titanate (PZT) that offers high piezoelectric performance under a large range of operating conditions. However, the toxicity of lead requires the replacement of PZT. The studied lead-free alternatives are commonly based on potassium sodium niobate (KNN) and bismuth sodium titanate (BNT), and more recently zirconium and calcium substituted barium titanate (BZT-BCT). The BZT-BCT system exhibits large piezoelectric coefficients that can exceed even those of most PZT compositions under certain conditions. Piezoelectricity was first discovered by Pierre and Jaque Curie in the year 1880. Nowadays, piezoelectric materials are used in many application such as high voltage generation in gas igniters, actuation in micro-positioning devices, generation and detection of acoustic waves, emitters and receivers for sonar technology, ultrasonic cleaning, ultrasound medical therapy, and micropumps for ink-jet printers. The most commonly used piezoelectric material since the 1950's is the solid solution system lead zirconate titanate (PZT) that offers high piezoelectric performance under a large range of operating conditions. However, the toxicity of lead requires the replacement of PZT. The studied lead-free alternatives are commonly based on potassium sodium niobate (KNN) and bismuth sodium titanate (BNT), and more recently zirconium and calcium substituted barium titanate (BZT-BCT). The BZT-BCT system exhibits large piezoelectric coefficients that can exceed even those of

  14. Accelerated Aging of Lead-Free Propellant

    NASA Technical Reports Server (NTRS)

    Furrow, Keith W.; Jervey, David D.

    2000-01-01

    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.

  15. Growth and orientation dependence of electrical properties of 0.92Na0.5Bi0.5TiO3-0.08 K0.5Bi0.5TiO3 lead-free piezoelectric single crystal

    NASA Astrophysics Data System (ADS)

    Sun, Renbing; Zhao, Xiangyong; Zhang, Qinhui; Fang, Bijun; Zhang, Haiwu; Li, Xiaobing; Lin, Di; Wang, Sheng; Luo, Haosu

    2011-06-01

    A 0.92Na0.5Bi0.5TiO3-0.08 K0.5Bi0.5TiO3 (0.92NBT-0.08KBT) lead-free piezoelectric single crystal with dimensions of Φ 35 × 10 mm was successfully grown by the top-seeded solution growth method. The effective segregation coefficient for K was calculated to be 0.27. An x-ray powder diffraction measurement showed that the as-grown crystal possesses a rhombohedral perovskite structure at room temperature. The room-temperature dielectric constants for poled <001>, <110>, and <111> oriented crystal samples are found to be 683, 567, and 435 at 1 kHz, respectively. The (Tm, ɛm) values for <001>, <110>, and <111> oriented crystals are (316 °C, 4318), (317 °C, 4160), and (318 °C, 4348) at 1 kHz, which indicate that the dielectric parameters of the as-grown crystals show weaker anisotropy. The curves, ɛ(T), for the three crystallographic orientations show two anomalies at about 170 and 320 °C, respectively, relating to the ferroelectric-antiferroelectric phase and the antiferroelectric-paraelectric phase. There is a thermal hysteresis, ΔT ≈ 35 °C for the ferroelectric-antiferroelectric phase transformation between heating and cooling. The antiferroelectric phase, the thermal hysteresis, and the dielectric relaxor behavior around 170 °C can be attributed to the formation of an intermediate orthorhombic modulated phase at 170-320 °C. For the <001>, <110>, and <111> crystal samples, the room-temperature piezoelectric constants, d33, reach 175, 130, and 70 pC/N, respectively. The remanent polarization for the <001>, <110>, and <111> crystal samples are 8.1, 10.8, and 13.5 μC/cm2, respectively, and the ratio is 1:1.33:1.67, close to 1:√2 :√3 . The diffusive factors, α, are found to be 1.94, 1.91, and 1.50 for the <001>, <110>, and <111> oriented crystal samples, which indicate that the antiferroelectric-paraelectric phase transition of the as-grown 0.92NBT-0.08KBT crystal is a strong diffuse one. The electromechanical coupling coefficients for the <001>, <110

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

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

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

  17. Hard X-ray nanofocusing using adaptive focusing optics based on piezoelectric deformable mirrors

    SciTech Connect

    Goto, Takumi; Nakamori, Hiroki; Sano, Yasuhisa; Matsuyama, Satoshi; Kimura, Takashi; Kohmura, Yoshiki; Tamasaku, Kenji; Yabashi, Makina; Ishikawa, Tetsuya

    2015-04-15

    An adaptive Kirkpatrick–Baez mirror focusing optics based on piezoelectric deformable mirrors was constructed at SPring-8 and its focusing performance characteristics were demonstrated. By adjusting the voltages applied to the deformable mirrors, the shape errors (compared to a target elliptical shape) were finely corrected on the basis of the mirror shape determined using the pencil-beam method, which is a type of at-wavelength figure metrology in the X-ray region. The mirror shapes were controlled with a peak-to-valley height accuracy of 2.5 nm. A focused beam with an intensity profile having a full width at half maximum of 110 × 65 nm (V × H) was achieved at an X-ray energy of 10 keV.

  18. Hard X-ray nanofocusing using adaptive focusing optics based on piezoelectric deformable mirrors.

    PubMed

    Goto, Takumi; Nakamori, Hiroki; Kimura, Takashi; Sano, Yasuhisa; Kohmura, Yoshiki; Tamasaku, Kenji; Yabashi, Makina; Ishikawa, Tetsuya; Yamauchi, Kazuto; Matsuyama, Satoshi

    2015-04-01

    An adaptive Kirkpatrick-Baez mirror focusing optics based on piezoelectric deformable mirrors was constructed at SPring-8 and its focusing performance characteristics were demonstrated. By adjusting the voltages applied to the deformable mirrors, the shape errors (compared to a target elliptical shape) were finely corrected on the basis of the mirror shape determined using the pencil-beam method, which is a type of at-wavelength figure metrology in the X-ray region. The mirror shapes were controlled with a peak-to-valley height accuracy of 2.5 nm. A focused beam with an intensity profile having a full width at half maximum of 110 × 65 nm (V × H) was achieved at an X-ray energy of 10 keV.

  19. Lead-free bearing alloys for engine applications

    NASA Astrophysics Data System (ADS)

    Ratke, Lorenz; Ågren, John; Ludwig, Andreas; Tonn, Babette; Gránásy, László; Mathiesen, Ragnvald; Arnberg, Lars; Anger, Gerd; Reifenhäuser, Bernd; Lauer, Michael; Garen, Rune; Gust, Edgar

    2005-10-01

    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.

  20. NASA-DoD Lead-Free Electronics Project

    NASA Technical Reports Server (NTRS)

    Kessel, Kurt

    2010-01-01

    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.

  1. Magnetoelectric effect in lead free piezoelectric Bi1/2Na1/2TiO3-modified CFO based magnetostrictive (Co0.6Zn0.4Fe1.7 Mn0.3O4) particulate nanocomposite prepared by sol-gel method

    NASA Astrophysics Data System (ADS)

    Thakur, Megha; Sharma, Puneet; Kumari, Mukesh; Singh, Anoop Pratap; Tyagi, Mintu

    2017-03-01

    Lead free magnetoelectric composites that comprise Co0.6Zn0.4Fe1.7Mn0.3O4 (CZFMO) and Bi1/2Na1/2TiO3 (BNT) were synthesized using sol-gel method and it's structural, dielectric, magnetic, ferroelectric and magnetoelectric (ME) properties were studied. The X-ray diffraction displayed the single phase formation of parent phases and the presence of two phases in the composites. The temperature dependent dielectric spectra of samples indicates two anomalies at 220 °C and 320 °C were ascribed to ferroelectric to antiferroelectric, and anti-ferroelectric to paraelectric phase transitions respectively. Room temperature (RT) magnetic measurements show that composites are soft magnetic. The composite with x=0.2, showed the large value of ME voltage coefficient (αE) 58 mV/cmOe. Moreover, these ME composites provide a great opportunity as potential lead free systems for multifunctional devices.

  2. Local and Global Properties of a Lead-Free Solder

    NASA Astrophysics Data System (ADS)

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

    2013-07-01

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

  3. Fabrication by Annealing at Approximately 1030°C and Electrical Characterization of Lead-Free (1 - x)Bi0.5K0.5TiO3-xBa(Fe0.5Nb0.5)0.05Ti0.95O3 Piezoelectric Ceramics

    NASA Astrophysics Data System (ADS)

    Truong-Tho, N.; Nghi-Nhan, N. T.

    2017-03-01

    Sintered (1 - x)Bi0.5K0.5TiO3-xBa(Fe0.5Nb0.5)0.05Ti0.95O3 [(1 - x)BKT-xBFNT] piezoelectric ceramics have been fabricated by conventional annealing at 1000°C to 1050°C. X-ray diffraction (XRD) analysis revealed that the 0.9BKT-0.1BFNT ceramic sintered at 1030°C showed high transition temperature of T C = 514°C due to presence of Bi4Ti3O12 in solid solution. Although the P-E ferroelectric loop was not yet saturated, the remanent polarization and coercive electric field of the 0.9BKT-0.1BFNT showed good values of P r = 18.5 μC/cm2 and E c = 4.3 kV/cm, respectively. The piezoelectric parameters of the ceramic included planar-mode electromechanical coupling factor of k p = 0.17 and mechanical quality factor of Q m = 145, larger than the values of 0.17 and 57, respectively, obtained for BKT ceramic.

  4. Phase transitions and the piezoelectricity around morphotropic phase boundary in Ba(Zr{sub 0.2}Ti{sub 0.8})O{sub 3}-x(Ba{sub 0.7}Ca{sub 0.3})TiO{sub 3} lead-free solid solution

    SciTech Connect

    Zhang, Le; Zhang, Ming; Wang, Liang; Zhou, Chao; Zhang, Zhen; Yao, Yonggang; Zhang, Lixue; Xue, Dezhen E-mail: xlou03@mail.xjtu.edu.cn Lou, Xiaojie E-mail: xlou03@mail.xjtu.edu.cn; Ren, Xiaobing E-mail: xlou03@mail.xjtu.edu.cn

    2014-10-20

    In this paper, two displacive phase transitions around the morphotropic phase boundary (MPB) in Ba(Zr{sub 0.2}Ti{sub 0.8})O{sub 3}-x(Ba{sub 0.7}Ca{sub 0.3})TiO{sub 3} (BZT-xBCT) ceramics were detected by inspecting two anomalies of the Raman Ti{sup 4+}-O{sup 2−} longitudinal optical mode (∼725 cm{sup −1}). Further, permittivity and X-ray diffraction results demonstrated these two phase transitions originate from tetragonal (T) to rhombohedral (R) through an intermediate orthorhombic (O) phase. Importantly, we found that the maximum piezoelectric response (d{sub 33} = 545pC/N) was achieved at the boundary between the T and O phase, indicating that the giant piezoelectricity of BZT-xBCT may mainly stem from the T-O phase boundary due to easier polarization rotation and larger lattice softening.

  5. NASA-DoD Lead-Free Electronics Project

    NASA Technical Reports Server (NTRS)

    Kessel, Kurt

    2007-01-01

    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.

  6. NASA-DoD Lead-Free Electronics Project

    NASA Technical Reports Server (NTRS)

    Kessel, Kurt R.

    2009-01-01

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

  7. NASA-DoD Lead-Free Electronics Project

    NASA Technical Reports Server (NTRS)

    Kessel, Kurt R.

    2009-01-01

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

  8. NASA-DoD Lead-Free Electronics Project

    NASA Technical Reports Server (NTRS)

    Kessel, Kurt

    2009-01-01

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

  9. Analysis of Lead-Free Piezoceramic-Based Power Ultrasonic Transducers for Wire Bonding.

    PubMed

    Mathieson, Andrew; DeAngelis, Dominick A

    2016-01-01

    Since the 1950s, lead zirconate-titanate (PZT) has been the dominant transduction material utilized in power ultrasonics, while lead-free piezoceramics have been largely neglected due to their relatively poor piezoelectric and electromechanical properties. However, the implementation of environmental directives that regulate and control the use of hazardous materials, such as lead, triggered a search for new high-performance lead-free piezoceramics. Recent advances have led to lead-free piezoceramics exhibiting properties similar to PZT, but despite this, reports utilizing these novel piezoceramics in practice are limited. This research employs a modified variant of bismuth sodium titanate (BNT) in a power ultrasonic transducer used for metal welding during the manufacture of semiconductors. The important factors for transducer reliability and performance are investigated, such as piezoceramic aging and stack preload level. It is reported that BNT-based transducers exhibit good stability, and can withstand a stack preload level of 90 MPa without depoling. Although the BNT-based transducers exhibited larger dissipative losses compared to identical PZT8-based transducers, the tool displacement gain was larger under constant current conditions. Semiconductor wire bonds which satisfied the commercial quality control requirements were also formed by this BNT-based transducer.

  10. Structural dependence of piezoelectric, dielectric and ferroelectric properties of K{sub 0.5}Na{sub 0.5}(Nb{sub 1−2x/5}Cu{sub x})O{sub 3} lead-free ceramics with high Q{sub m}

    SciTech Connect

    Tan, Xiaohui; Fan, Huiqing; Ke, Shanming; Zhou, Limin; Mai, Yiu-Wing; Huang, Haitao

    2012-12-15

    Graphical abstract: Display Omitted Highlights: ► Double hysteresis loops were observed in K{sub 0.5}Na{sub 0.5}(Nb{sub 1−2x/5}Cu{sub x})O{sub 3}. ► Cu substitution caused structural discontinuity in KNNC. ► Dimeric defect complex (Cu{sup ‴}{sub Nb}–V{sub O}··){sup ′} with a dipole moment was formed in KNNC. -- Abstract: (K{sub 0.5}Na{sub 0.5})(Nb{sub 1−2x/5}Cu{sub x})O{sub 3} (abbreviated as KNNC, x = 0–2%) lead-free ceramics were synthetized by the solid state solution method. Pure perovskite phase with orthorhombic symmetry was observed. The evolution of the structure of KNNC was examined by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Raman scattering spectra techniques. Our results revealed that, defect dipoles (Cu{sup ‴}{sub Nb}–V{sub O}··){sup ′} were formed and provided a restoring force to reverse the switched polarization, which resulted in double P–E hysteresis loops in KNNC with Cu doping at x = 0.75% and 1%. However, non-polar defect complex (V{sub O}··–Cu{sup ‴}{sub Nb}–V{sub O}··)· caused a lattice shrinkage and the observed square shaped P–E loops in KNNC ceramics under high doping levels (x > 1%).

  11. NASA-DoD Lead-Free Electronics Project

    NASA Technical Reports Server (NTRS)

    Kessel, Kurt R.

    2009-01-01

    The primary technical objective of this project is to undertake comprehensive testing to generate information on failure modes/criteria to better understand the reliability of: (1) Packages (e.g., Thin Small Outline Package [TSOP], Ball Grid Array [BGA], Plastic Dual In-line Package [PDIP]) assembled and reworked with lead-free alloys, (2) Packages (e.g., TSOP, BGA, PDIP) assembled and reworked with mixed (lead/lead-free) alloys.

  12. NASA-DoD Lead-Free Electronics Project

    NASA Technical Reports Server (NTRS)

    Kessel, Kurt

    2010-01-01

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

  13. Lead-free Organic-Inorganic Hybrid Perovskites for Photovoltaic Applications: Recent Advances and Perspectives.

    PubMed

    Shi, Zejiao; Guo, Jia; Chen, Yonghua; Li, Qi; Pan, Yufeng; Zhang, Haijuan; Xia, Yingdong; Huang, Wei

    2017-02-03

    Organic-inorganic hybrid halide perovskites (e.g., MAPbI3 ) have recently emerged as novel active materials for photovoltaic applications with power conversion efficiency over 22%. Conventional perovskite solar cells (PSCs); however, suffer the issue that lead is toxic to the environment and organisms for a long time and is hard to excrete from the body. Therefore, it is imperative to find environmentally-friendly metal ions to replace lead for the further development of PSCs. Previous work has demonstrated that Sn, Ge, Cu, Bi, and Sb ions could be used as alternative ions in perovskite configurations to form a new environmentally-friendly lead-free perovskite structure. Here, we review recent progress on lead-free PSCs in terms of the theoretical insight and experimental explorations of the crystal structure of lead-free perovskite, thin film deposition, and device performance. We also discuss the importance of obtaining further understanding of the fundamental properties of lead-free hybrid perovskites, especially those related to photophysics.

  14. Piezoelectric properties of Li- and Ta-modified (K0.5Na0.5)NbO3 ceramics

    NASA Astrophysics Data System (ADS)

    Hollenstein, Evelyn; Davis, Matthew; Damjanovic, Dragan; Setter, Nava

    2005-10-01

    Lead-free, potassium sodium niobate piezoelectric ceramics substituted with lithium (K0.5-x/2,Na0.5-x/2,Lix)NbO3 or lithium and tantalum (K0.5-x/2,Na0.5-x/2,Lix)(Nb1-y,Tay)O3 have been synthesized by traditional solid state sintering. The compositions chosen are among those recently reported to show high piezoelectric properties [Y. Saito, H. Takao, T. Tani, T. Nonoyama, K. Takatori, T. Homma, T. Nagaya, and M. Nakamura, Nature (London) 42, 84 (2004); Y. Guo, K. Kakimoto, and H. Ohsato, Appl. Phys. Lett. 85, 4121 (2004); Mater. Lett. 59, 241 (2005)]. We show that high densities and piezoelectric properties can be obtained for all compositions by pressureless sintering in air, without cold isostatic pressing, and without any sintering aid or special powder treatment. Resonance and converse piezoelectric (strain-field) measurements show a thickness coupling coefficient kt of 53% and converse piezoelectric coefficient d33 around 200pm/V for the Li-substituted ceramics, and a kt of 52% and d33 over 300pm/V for the Li- and Ta-modified samples. The unipolar strain-field hysteresis is small and comparable to that measured under similar conditions in hard Pb(Zr ,Ti)O3. A peak of piezoelectric properties can be noted close to the morphotropic phase boundary. These ceramics look very promising as possible, practicable, lead-free replacements for lead zirconate titanate.

  15. High voltage generation from lead-free magnetoelectric coaxial nanotube arrays and their applications in nano energy harvesters

    NASA Astrophysics Data System (ADS)

    Lekha, C. S. Chitra; Kumar, Ajith S.; Vivek, S.; Rasi, U. P. Mohammed; Venkata Saravanan, K.; Nandakumar, K.; Nair, Swapna S.

    2017-02-01

    Harvesting energy from surrounding vibrations and developing self-powered portable devices for wireless and mobile electronics have recently become popular. Here the authors demonstrate the synthesis of piezoelectric energy harvesters based on nanotube arrays by a wet chemical route, which requires no sophisticated instruments. The energy harvester gives an output voltage of 400 mV. Harvesting energy from a sinusoidal magnetic field is another interesting phenomenon for which the authors fabricated a magnetoelectric energy harvester based on piezoelectric-magnetostrictive coaxial nanotube arrays. Piezoelectric K0.5Na0.5NbO3 (KNN) is fabricated as the shell and magnetostrictive CoFe2O4 (CFO) as the core of the composite coaxial nanotubes. The delivered voltages are as high as 300 mV at 500 Hz and at a weak ac magnetic field of 100 Oe. Further tailoring of the thickness of the piezoelectric and magnetic layers can enhance the output voltage by several orders. Easy, single-step wet chemical synthesis enhances the industrial upscaling potential of these nanotubes as energy harvesters. In view of the excellent properties reported here, the lead-free piezoelectric component (KNN) in this nanocomposite should be explored for eco-friendly piezoelectric as well as magnetoelectric power generators in nanoelectromechanical systems (NEMS).

  16. High voltage generation from lead-free magnetoelectric coaxial nanotube arrays and their applications in nano energy harvesters.

    PubMed

    Lekha, C S Chitra; Kumar, Ajith S; Vivek, S; Rasi, U P Mohammed; Saravanan, K Venkata; Nandakumar, K; Nair, Swapna S

    2017-02-03

    Harvesting energy from surrounding vibrations and developing self-powered portable devices for wireless and mobile electronics have recently become popular. Here the authors demonstrate the synthesis of piezoelectric energy harvesters based on nanotube arrays by a wet chemical route, which requires no sophisticated instruments. The energy harvester gives an output voltage of 400 mV. Harvesting energy from a sinusoidal magnetic field is another interesting phenomenon for which the authors fabricated a magnetoelectric energy harvester based on piezoelectric-magnetostrictive coaxial nanotube arrays. Piezoelectric K0.5Na0.5NbO3 (KNN) is fabricated as the shell and magnetostrictive CoFe2O4 (CFO) as the core of the composite coaxial nanotubes. The delivered voltages are as high as 300 mV at 500 Hz and at a weak ac magnetic field of 100 Oe. Further tailoring of the thickness of the piezoelectric and magnetic layers can enhance the output voltage by several orders. Easy, single-step wet chemical synthesis enhances the industrial upscaling potential of these nanotubes as energy harvesters. In view of the excellent properties reported here, the lead-free piezoelectric component (KNN) in this nanocomposite should be explored for eco-friendly piezoelectric as well as magnetoelectric power generators in nanoelectromechanical systems (NEMS).

  17. Rate dependent direct inverse hysteresis compensation of piezoelectric micro-actuator used in dual-stage hard disk drive head positioning system.

    PubMed

    Rahman, Md Arifur; Al Mamun, Abdullah; Yao, Kui

    2015-08-01

    The head positioning servo system in hard disk drive is implemented nowadays using a dual-stage actuator—the primary stage consisting of a voice coil motor actuator providing long range motion and the secondary stage controlling the position of the read/write head with fine resolution. Piezoelectric micro-actuator made of lead zirconate titanate (PZT) has been a popular choice for the secondary stage. However, PZT micro-actuator exhibits hysteresis—an inherent nonlinear characteristic of piezoelectric material. The advantage expected from using the secondary micro-actuator is somewhat lost by the hysteresis of the micro-actuator that contributes to tracking error. Hysteresis nonlinearity adversely affects the performance and, if not compensated, may cause inaccuracy and oscillation in the response. Compensation of hysteresis is therefore an important aspect for designing head-positioning servo system. This paper presents a new rate dependent model of hysteresis along with rigorous analysis and identification of the model. Parameters of the model are found using particle swarm optimization. Direct inverse of the proposed rate-dependent generalized Prandtl-Ishlinskii model is used as the hysteresis compensator. Effectiveness of the overall solution is underscored through experimental results.

  18. Rate dependent direct inverse hysteresis compensation of piezoelectric micro-actuator used in dual-stage hard disk drive head positioning system

    NASA Astrophysics Data System (ADS)

    Rahman, Md. Arifur; Al Mamun, Abdullah; Yao, Kui

    2015-08-01

    The head positioning servo system in hard disk drive is implemented nowadays using a dual-stage actuator—the primary stage consisting of a voice coil motor actuator providing long range motion and the secondary stage controlling the position of the read/write head with fine resolution. Piezoelectric micro-actuator made of lead zirconate titanate (PZT) has been a popular choice for the secondary stage. However, PZT micro-actuator exhibits hysteresis—an inherent nonlinear characteristic of piezoelectric material. The advantage expected from using the secondary micro-actuator is somewhat lost by the hysteresis of the micro-actuator that contributes to tracking error. Hysteresis nonlinearity adversely affects the performance and, if not compensated, may cause inaccuracy and oscillation in the response. Compensation of hysteresis is therefore an important aspect for designing head-positioning servo system. This paper presents a new rate dependent model of hysteresis along with rigorous analysis and identification of the model. Parameters of the model are found using particle swarm optimization. Direct inverse of the proposed rate-dependent generalized Prandtl-Ishlinskii model is used as the hysteresis compensator. Effectiveness of the overall solution is underscored through experimental results.

  19. NASA-DoD Lead-Free Electronics Project

    NASA Technical Reports Server (NTRS)

    Kessel, Kurt

    2011-01-01

    Original Equipment Manufacturers (OEMs). depots. and support contractors have to be prepared to deal with an electronics supply chain thaI increasingly provides parts with lead-free finishes. some labeled no differently and intenningled with their SnPb counterparts. Allowance oflead-free components presents one of the greatest risks to the reliability of military and aerospace electronics. The introduction of components with lead-free lenninations, tennination finishes, or circuit boards presents a host of concerns to customers. suppliers, and maintainers of aerospace and military electronic systems such as: 1. Electrical shorting due to tin whiskers; 2. Incompatibility oflead-free processes and parameters (including higher melting points of lead-free alloys) with other materials in the system; and 3. Unknown material properties and incompatibilities that could reduce solder joint re liability.

  20. Structural And Electrical Analysis Of Lead Free BZT-xBCT Ceramics

    NASA Astrophysics Data System (ADS)

    Bhardwaj, Chandan; Kumar, Ashvani; Kaur, Davinder

    2010-12-01

    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.

  1. Structural And Electrical Analysis Of Lead Free BZT-xBCT Ceramics

    SciTech Connect

    Bhardwaj, Chandan; Kumar, Ashvani; Kaur, Davinder

    2010-12-01

    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.

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

    PubMed

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

    2013-07-01

    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 320MHz. The center frequency of >300MHz 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 -6dB 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 -60dB. In addition to the pulse-echo measurement, a 6μm tungsten wire phantom was also imaged with a 205MHz transducer to demonstrate the imaging capability. The measured -6dB axial and lateral resolutions were found to be 12μm and 50μm, 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.

  3. [Shielding evaluation of lead-free board for diagnostic X-rays].

    PubMed

    Katoh, Yoh; Tsukada, Masaru; Mita, Sogo; Fukushi, Masahiro; Nyui, Yoshiyuki; Abe, Shinji; Kimura, Junichi

    2010-12-20

    For physical foundation data used in the shielding calculation of structural facilities such as a radiation room, there are air kerma transmissions concerning the thickness of shielding objects, and half value layers and tenth value layers concerning a greatly attenuated wide X-ray beam. Accordingly, we evaluated the above-mentioned items with a lead-free board, which is mixed sulfuric acid calcium and barium sulfate with equiponderance for the amount of sulfuric acid calcium included in the usual plasterboard. Permeability in NCRP Report 147 is expressed by 3 parameters, α, β and γ, and shielding objects x. It showed that it corresponds to the measurement point and permeability curve with parameters, α, β and γ obtained by nonlinear regression analysis. Furthermore, we calculated the half value layer and tenth value layer concerning the greatly attenuated wide X-ray beam. The evaluated lead-free board, used in this examination, is useful as the shielding material for the diagnosis X-ray and, moreover, the partition wall materials are hard enough, with a board that is even heavier than the usual plaster board. Besides, the use of lead-free materials is friendly to the general environment.

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

    SciTech Connect

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

    2007-12-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2007-12-01

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

  6. Lead-Free Experiment in a Space Environment

    NASA Technical Reports Server (NTRS)

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

    2012-01-01

    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.

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

    SciTech Connect

    Lu, Shengbo; Xu, Zhengkui; Kwok, K. W.; Chan, Helen L. W.

    2014-07-28

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

  8. Giant electric-field-induced strain in lead-free piezoelectric materials

    PubMed Central

    Chen, Lan; Yang, Yurong; Meng, X. K.

    2016-01-01

    First-principles calculations are performed to investigate the structures, electrical, and magnetic properties of compressive BiFeO3 films under electric-field and pressure perpendicular to the films. A reversible electric-field-induced strain up 10% is achieved in the compressive BiFeO3 films. The giant strain originates from rhombohedral-tetragonal (R-T) phase transition under electric-filed, and is recoverable from tetragonal-rhombohedral (T-R) phase transition by compressive stress. Additionally, the weak ferromagnetism in BiFeO3 films is largely changed in R-T phase transition under electric-filed and T-R phase transition under pressure – reminiscent of magnetoelectric effect and magnetoelastic effect. These results suggest exciting device opportunities arising from the giant filed-induced strain, large magnetoelectric effect and magnetoelastic effect. PMID:27139526

  9. Underfill process development for lead free flip chip assembly

    NASA Astrophysics Data System (ADS)

    Chaware, Raghunandan

    Underfills are used to enhance the long-term reliability of the flip-chip solder joints. More specifically, the function of the underfill is to couple the chip to the substrate, wherein the shear stresses experienced by the solder joints are converted to bending stresses. The underfill flows under the die due to the influence of strong capillary forces. The flow of the underfill under the chip depends on various factors such as the viscosity of the underfill, contact angle, surface tension, temperature, underfill gap, substrate design, bump pattern, bump density, and size of the chip. The flow of underfill is also influenced by the cleanliness of the substrate, the cleanliness of the underside of the chip, and the flux residues. The interaction between the underfill and the substrate affects not only gap filling, but also the filleting of the underfill. Similarly, the underfill-flux interaction directly affects the quality of underfilling and the reliability of the flip chip assembly. In the case of lead free flip chip assembly, the major concerns vis-a-vis process development for a large chip with a small bump pitch (less than 190 mum) include lower throughput, voiding under the chip, and critical reliability performance. The principal objective of this research endeavor was to investigate the fundamental issues that relate to the process and reliability aspects of underfilling of lead free flip chip assemblies. In order to develop a robust underfilling process, the effect of different process parameters and their interaction with the material properties were studied. In order to improve the compatibility between the underfill and the flux, a new epoxy flux that was compatible with the lead free assembly process was developed. The performance of the epoxy was also compared with the performance of various rosin based fluxes. This study also helped in identifying the critical parameters that can affect the assembly yields. This research endeavor successfully

  10. Piezoelectric enhancement under negative pressure

    PubMed Central

    Kvasov, Alexander; McGilly, Leo J.; Wang, Jin; Shi, Zhiyong; Sandu, Cosmin S.; Sluka, Tomas; Tagantsev, Alexander K.; Setter, Nava

    2016-01-01

    Enhancement of ferroelectric properties, both spontaneous polarization and Curie temperature under negative pressure had been predicted in the past from first principles and recently confirmed experimentally. In contrast, piezoelectric properties are expected to increase by positive pressure, through polarization rotation. Here we investigate the piezoelectric response of the classical PbTiO3, Pb(Zr,Ti)O3 and BaTiO3 perovskite ferroelectrics under negative pressure from first principles and find significant enhancement. Piezoelectric response is then tested experimentally on free-standing PbTiO3 and Pb(Zr,Ti)O3 nanowires under self-sustained negative pressure, confirming the theoretical prediction. Numerical simulations verify that negative pressure in nanowires is the origin of the enhanced electromechanical properties. The results may be useful in the development of highly performing piezoelectrics, including lead-free ones. PMID:27396411

  11. Piezoelectric enhancement under negative pressure

    NASA Astrophysics Data System (ADS)

    Kvasov, Alexander; McGilly, Leo J.; Wang, Jin; Shi, Zhiyong; Sandu, Cosmin S.; Sluka, Tomas; Tagantsev, Alexander K.; Setter, Nava

    2016-07-01

    Enhancement of ferroelectric properties, both spontaneous polarization and Curie temperature under negative pressure had been predicted in the past from first principles and recently confirmed experimentally. In contrast, piezoelectric properties are expected to increase by positive pressure, through polarization rotation. Here we investigate the piezoelectric response of the classical PbTiO3, Pb(Zr,Ti)O3 and BaTiO3 perovskite ferroelectrics under negative pressure from first principles and find significant enhancement. Piezoelectric response is then tested experimentally on free-standing PbTiO3 and Pb(Zr,Ti)O3 nanowires under self-sustained negative pressure, confirming the theoretical prediction. Numerical simulations verify that negative pressure in nanowires is the origin of the enhanced electromechanical properties. The results may be useful in the development of highly performing piezoelectrics, including lead-free ones.

  12. Lead-free 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 nanowires for energy harvesting.

    PubMed

    Zhou, Zhi; Bowland, Christopher C; Malakooti, Mohammad H; Tang, Haixiong; Sodano, Henry A

    2016-03-07

    Lead-free piezoelectric nanowires (NWs) show strong potential in sensing and energy harvesting applications due to their flexibility and ability to convert mechanical energy to electric energy. Currently, most lead-free piezoelectric NWs are produced through low yield synthesis methods and result in low electromechanical coupling, which limit their efficiency as energy harvesters. In order to alleviate these issues, a scalable method is developed to synthesize perovskite type 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 (BZT-BCT) NWs with high piezoelectric coupling coefficient. The piezoelectric coupling coefficient of the BZT-BCT NWs is measured by a refined piezoresponse force microscopy (PFM) testing method and shows the highest reported coupling coefficient for lead-free piezoelectric nanowires of 90 ± 5 pm V(-1). Flexible nanocomposites utilizing dispersed BZT-BCT NWs are fabricated to demonstrate an energy harvesting application with an open circuit voltage of up to 6.25 V and a power density of up to 2.25 μW cm(-3). The high electromechanical coupling coefficient and high power density demonstrated with these lead-free NWs produced via a scalable synthesis method shows the potential for high performance NW-based devices.

  13. Lead-free 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 nanowires for energy harvesting

    NASA Astrophysics Data System (ADS)

    Zhou, Zhi; Bowland, Christopher C.; Malakooti, Mohammad H.; Tang, Haixiong; Sodano, Henry A.

    2016-02-01

    Lead-free piezoelectric nanowires (NWs) show strong potential in sensing and energy harvesting applications due to their flexibility and ability to convert mechanical energy to electric energy. Currently, most lead-free piezoelectric NWs are produced through low yield synthesis methods and result in low electromechanical coupling, which limit their efficiency as energy harvesters. In order to alleviate these issues, a scalable method is developed to synthesize perovskite type 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 (BZT-BCT) NWs with high piezoelectric coupling coefficient. The piezoelectric coupling coefficient of the BZT-BCT NWs is measured by a refined piezoresponse force microscopy (PFM) testing method and shows the highest reported coupling coefficient for lead-free piezoelectric nanowires of 90 +/- 5 pm V-1. Flexible nanocomposites utilizing dispersed BZT-BCT NWs are fabricated to demonstrate an energy harvesting application with an open circuit voltage of up to 6.25 V and a power density of up to 2.25 μW cm-3. The high electromechanical coupling coefficient and high power density demonstrated with these lead-free NWs produced via a scalable synthesis method shows the potential for high performance NW-based devices.

  14. Properties of lead-free BZT-BCT ceramics synthesized using nanostructured ZnO as a sintering aid

    NASA Astrophysics Data System (ADS)

    Tuan, Dang Anh; Tung, Vo Thanh; Chuong, Truong Van; Hong, Le Van

    2015-11-01

    This article studies the microstructure and piezoelectric properties of low sintering temperature lead-free ceramics 0.52(Ba0.7Ca0.3)TiO3 - 0.48Ba(Zr0.2Ti0.8)O3-doped with ZnO nanoparticles (noted as 0.48BZT-y, y is content of ZnO in wt%, y =0.00, 0.05, 0.10, 0.15, 0.20 and 0.25). The obtained results of Raman scattering and dielectric measurements have confirmed that Zn2+ has occupied B site, to cause a deformation in the ABO3-type lattice of the 0.48BZT-y compounds. The 0.15 wt% ZnO-doped ceramic sintered at 1350∘C exhibited excellent piezoelectric parameters: d33 = 420pC/N, d31 = -174pC/N, kp = 0.483, kt = 0.423 and k33 = 0.571. The obtained results indicate that the high-quality lead-free BZT-BCT ceramic could be successfully synthesized at a low sintering temperature of 1350∘C by doping an appropriated amount of ZnO.

  15. High temperature lead-free solder for microelectronics

    NASA Astrophysics Data System (ADS)

    Gayle, Frank W.; Becka, Gary; Syed, Ahmer; Badgett, Jerry; Whitten, Gordon; Pan, Tsung-Yu; Grusd, Angela; Bauer, Brian; Lathrop, Rick; Slattery, Jim; Anderson, Iver; Foley, Jim; Gickler, Alan; Napp, Duane; Mather, John; Olson, Chris

    2001-06-01

    This paper reports results of a four-year industrial consortium effort to develop lead-free solders for high-temperature applications (up to 160°C). Work included preliminary evaluations of 32 tin-based alloys, a screening of the thermomechanical fatigue performance of 13 promising alloys, and a full manufacturability and fatigue testing of the seven most promising of those alloys, namely Sn-3.5Ag, Sn-4Ag-1Cu, Sn-4Ag-0.5Cu, Sn-2.5Ag-0.8Cu-0.5Sb, Sn-4.6Ag-1.6Cu-1Sb-1Bi, Sn-3.3Ag-1Cu-3.3Bi, and Sn-3.5Ag-1.5In (compositions in weight percent). Eight different components were used on the reliability test vehicle, and the alloys were compared through Weibull analysis. In addition, the same seven experimental alloys were tested with ball grid array packages cycled up to 100°C or 125°C. All the lead-free alloys performed well, but those containing bismuth showed especially outstanding performance. In general, the ternary and higher alloys performed as well or better than the industry standard tin-silver eutectic, suggesting that solders other than the tin-silver eutectic should be considered for high-reliability, high-temperature applications.

  16. Feasibility study of thermal energy harvesting using lead free pyroelectrics

    NASA Astrophysics Data System (ADS)

    Karim, Hasanul; Sarker, Md Rashedul H.; Shahriar, Shaimum; Arif Ishtiaque Shuvo, Mohammad; Delfin, Diego; Hodges, Deidra; (Bill Tseng, Tzu-Liang; Roberson, David; Love, Norman; Lin, Yirong

    2016-05-01

    Energy harvesting has significant potential for applications in energizing wireless sensors and charging energy storage devices. To date, one of the most widely investigated materials for mechanical and thermal energy harvesting is lead zirconate titanate (PZT). However, lead has detrimental effects on the environment and on health. Hence, alternative materials are required for this purpose. In this paper, a lead free material, lithium niobate (LNB) is investigated as a potential material for pyroelectric energy harvesting. Although its theoretical pyroelectric properties are lower compared to PZT, it has better properties than other lead free alternatives such as ZnO. In addition, LNB has a high Curie temperature of about 1142 °C, which makes it applicable for high temperature energy harvesting, where other pyroelectric ceramics are not suitable. Herein, an energy harvesting and storage system composed of a single crystal LNB and a porous carbon-based super-capacitor was investigated. It is found that with controlled heating and cooling, a single wafer of LNB (75 mm diameter and 0.5 mm thickness) could generate 437.72 nW cm-3 of power and it could be used to charge a super-capacitor with a charging rate of 2.63 mV (h cm3)-1.

  17. Nanoindentation on SnAgCu lead-free solder joints and analysis

    NASA Astrophysics Data System (ADS)

    Xu, Luhua; Pang, John H. L.

    2006-12-01

    The lead-free SnAgCu (SAC) solder joint on copper pad with organic solderability preservative (Cu-OSP) and electroless nickel and immersion gold (ENIG) subjected to thermal testing leads to intermetallic growth. It causes corresponding reliability concerns at the interface. Nanoindentation characterization on SnAgCu solder alloy, intermetallic compounds (IMCs), and the substrates subjected to thermal aging is reported. The modulus and hardness of thin IMC layers were measured by nanoindentation continuous stiffness measurement (CSM) from planar IMC surface. When SAC/Ni(Au) solder joints were subject to thermal aging, the Young’s modulus of the NiCuSn IMC at the SAC/ENIG specimen changed from 207 GPa to 146 GPa with different aging times up to 500 h. The hardness decreased from 10.0 GPa to 7.3 GPa. For the SAC/Cu-OSP reaction couple, the Young’s modulus of Cu6Sn5 stayed constant at 97.0 GPa and hardness about 5.7 GPa. Electron-probe microanalysis (EPMA) was used to thermal aging. The creep effect on the measured result was analyzed when measuring SnAgCu solder; it was found that the indentation penetration, and thus the hardness, is loading rate dependent. With the proposed constant P/P experiment, a constant indentation strain rate h/h and hardness could be achieved. The log-log plot of indentation strain rate versus hardness for the data from the constant P/P experiments yields a slope of 7.52. With the optimized test method and CSM Technique, the Modulus of SAC387 solder alloy and all the layers in a solder joint were investigated.

  18. Lead-free piezoelectric ceramics based on (0.97 - x)K0.48Na0.52NbO3-0.03Bi0.5(Na0.7K0.2Li0.1)0.5ZrO3-xB0.5Na0.5TiO3 ternary system

    NASA Astrophysics Data System (ADS)

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

    2013-09-01

    In this work, the ternary system of potassium-sodium niobate has been designed to enhance the piezoelectric properties without sacrificing the Curie temperature greatly, and (0.97 - x)K0.48Na0.52NbO3-0.03Bi0.5(Na0.7K0.2Li0.1)0.5ZrO3-xB0.5Na0.5TiO3 ceramics have been prepared by the conventional solid-state method. The effect of B0.5Na0.5TiO3 content on the microstructure and electrical properties of the ceramics is studied. The phase diagram shows a phase boundary of the rhombohedral-tetragonal (R-T) phase coexistence in the composition range of 0.5% < x < 1.5%, and then an enhanced dielectric, ferroelectric, and piezoelectric behavior is obtained at such a phase boundary zone. The ceramic with x = 0.01 has an optimum electrical behavior of d33 ˜ 285 pC/N, kp ˜ 0.40, ɛr ˜ 1235, tan δ ˜ 0.031, Pr ˜ 14.9 μC/cm2, and Ec ˜ 15.2 kV/cm, together with a high Curie temperature of ˜347 °C. The large d33 in such a ternary system is due to a composition-induced R-T phase transition and a higher ɛrPr, and the thermal stability performance is strongly dependent on the phase structure. As a result, the design of the ternary system is an effective way to enhance the piezoelectric properties of potassium-sodium niobate materials.

  19. Electric fatigue process in lead-free alkali niobate ceramics at various pressures and temperatures

    NASA Astrophysics Data System (ADS)

    Martin, Alexander; Kakimoto, Ken-ichi

    2015-10-01

    Electric fatigue tests are important for evaluating the reliability of piezoceramics. However, these tests have not been the focus of studies of lead-free alkali niobate (NKN) ceramics so far. For this purpose, two different materials, Li0.06Na0.47K0.47NbO3 (LNKN6) and Na0.55K0.45NbO3 + 0.25% MnO (Mn-NKN), have been examined at various uniaxial pressures ranging from 0.1 to 100 MPa and various temperatures ranging from room temperature to 150 °C. It was shown that the harder ferroelectric Mn-NKN could maintain its piezoelectric properties at pressures up to 25 MPa. When bipolar fatigue occurred under pressures over the coercive stress of ∼30 MPa, the sample depolarized and formed microcracks. In contrast, the softer LNKN6 did not show fatigue at higher pressures between 25 and 50 MPa. However, in both materials, higher temperatures enhanced domain wall and charge carrier movements and conclusively domain wall pinning.

  20. Piezoelectric Polymers

    NASA Technical Reports Server (NTRS)

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

    2001-01-01

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

  1. Mechanical Properties and Microstructure Investigation of Lead Free Solder

    NASA Technical Reports Server (NTRS)

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

    2005-01-01

    While the electronics industry appears to be focusing on Sn-Ag-Cu as the alloy of choice for lead free electronics assembly, ,the exact composition varies by geographic region, supplier and user. Add to that dissolved copper and silver from the printed circuit board traces and surface finish, and there can be significant variation in the final solder joint composition. A systematic study of the mechanical and microstructural properties of Sn-Ag-Cu alloys with Ag varying from 2wt% to 4wt% and Cu varying from 0.5wt% to lSwt%, was undertaken in this research study. Different sample preparation techniques (water quenched, oil quenched and water quenched followed by reflow) were explored and the resulting microstructure compared to that of a typical reflowed lead free chip scale package (CSP) solder joint. Tensile properties (modulus, 0.2% yield strength and the ultimate tensile strength) and creep behavior of selected alloy compositions (Sn-4Ag-1 X u , Sn-4Ag-OSCu, Sn- 2Ag-1 X u , Sn-2Ag-OSCu, Sn-3.5Ag-O.SCu) were determined for three conditions: as- cast; aged for 100 hours at 125OC; and aged for 250 hours at 125OC. There was no significant difference in Young's Modulus as a function of alloy composition. After an initial decrease in modulus after 100 hours at 125"C, there was an insignificant change with further aging. The distribution of 0.2% strain yield stress and ultimate tensile strength as a function of alloy composition was more significant and decreased with aging time and temperature. The microstructures of these alloys were examined using light and scanning electron microscopy (LM and SEM) respectively and SEM based energy dispersive x-ray spectroscopy (EDS). Fracture surface and cross-section analysis were performed on the specimens after creep testing. The creep testing results and the effect of high temperature aging on mechanical properties is presented for the oil quenched samples. In general the microstructure of oil quenched specimen exhibited a

  2. An Approach for Impression Creep of Lead Free Microelectronic Solders

    NASA Astrophysics Data System (ADS)

    Anastasio, Onofrio A.

    2002-06-01

    Currently, the microelectronics industry is transitioning from lead-containing to lead-free solders in response to legislation in the EU and Japan. Before an alternative alloy can be designated as a replacement for current Pb-Sn extensive testing must be accomplished. One major characteristic of the alloy that must be considered is creep. Traditionally, creep testing requires numerous samples and a long tin, which thwarts the generation of comprehensive creep databases for difficult to prepare samples such as microelectronic solder joints. However, a relatively new technique, impression creep enables us to rapidly generate creep data. This test uses a cylindrical punch with a flat end to make an impression on the surface of a specimen under constant load. The steady state velocity of the indenter is found to have the same stress and temperature dependence as the conventional unidirectional creep test using bulk specimens. This thesis examines impression creep tests of eutectic Sn-Ag. A testing program and apparatus was developed constructed based on a servo hydraulic test frame. The apparatus is capable of a load resolution of 0.01N with a stability of plus/minus 0.1N, and a displacement resolution of 0.05 microns with a stability of plus/minus 0.1 microns. Samples of eutectic Sn-Ag solder were reflowed to develop the microstructure used in microelectronic packaging. Creep tests were conducted at various stresses and temperatures and showed that coarse microstructures creep more rapidly than the microstructures in the tested regime.

  3. Visualization of polar nanoregions in lead-free relaxors via piezoresponse force microscopy in torsional dual AC resonance tracking mode

    NASA Astrophysics Data System (ADS)

    Liu, Na; Dittmer, Robert; Stark, Robert W.; Dietz, Christian

    2015-07-01

    Polar nanoregions (PNRs) play a key role in the functionality of relaxor ferroelectrics; however, visualizing them in lead-free relaxor ferroelectrics with high lateral resolution is still challenging. Thus, we studied herein the local ferroelectric domain distribution of the lead-free bismuth-based (1 - x)(Bi1/2Na1/2TiO3-Bi1/2K1/2TiO3) - x(Bi1/2Mg1/2TiO3) piezoceramics which show a relaxor behavior using dual AC resonance tracking (DART) piezoresponse force microscopy (PFM). By using excitation frequencies at either side of the contact resonance peak of the torsional cantilever vibration, an enhanced contrast in the amplitude and phase images of the piezoresponse can be achieved. Additionally, this tracking technique reduces the topographical crosstalk while mapping the local electromechanical properties. The true drive amplitude, drive phase, contact resonant frequency and quality factor can be estimated from DART-PFM data obtained with vertically or torsionally vibrating cantilevers. This procedure yields a three-dimensional quantitative map of the local piezoelectric properties of the relaxor ferroelectric samples. With this approach, torsional DART allowed for the visualization of fine substructures within the monodomains, suggesting the existence of PNRs in relaxor ferroelectrics. The domain structures of the PNRs were visualized with high precision, and the local electromechanical characteristics of the lead-free relaxor ferroelectrics were quantitatively mapped.Polar nanoregions (PNRs) play a key role in the functionality of relaxor ferroelectrics; however, visualizing them in lead-free relaxor ferroelectrics with high lateral resolution is still challenging. Thus, we studied herein the local ferroelectric domain distribution of the lead-free bismuth-based (1 - x)(Bi1/2Na1/2TiO3-Bi1/2K1/2TiO3) - x(Bi1/2Mg1/2TiO3) piezoceramics which show a relaxor behavior using dual AC resonance tracking (DART) piezoresponse force microscopy (PFM). By using excitation

  4. Piezoelectric valve

    SciTech Connect

    Petrenko, Serhiy Fedorovich

    2013-01-15

    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.

  5. Lead-Free Propellant for Propellant Actuated Devices

    NASA Technical Reports Server (NTRS)

    Goodwin, John L.

    2000-01-01

    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

  6. Unleashing the Full Sustainable Potential of Thick Films of Lead-Free Potassium Sodium Niobate (K0.5Na0.5NbO3) by Aqueous Electrophoretic Deposition.

    PubMed

    Mahajan, Amit; Pinho, Rui; Dolhen, Morgane; Costa, M Elisabete; Vilarinho, Paula M

    2016-05-31

    A current challenge for the fabrication of functional oxide-based devices is related with the need of environmental and sustainable materials and processes. By considering both lead-free ferroelectrics of potassium sodium niobate (K0.5Na0.5NbO3, KNN) and aqueous-based electrophoretic deposition here we demonstrate that an eco-friendly aqueous solution-based process can be used to produce KNN thick coatings with improved electromechanical performance. KNN thick films on platinum substrates with thickness varying between 10 and 15 μm have a dielectric permittivity of 495, dielectric losses of 0.08 at 1 MHz, and a piezoelectric coefficient d33 of ∼70 pC/N. At TC these films display a relative permittivity of 2166 and loss tangent of 0.11 at 1 MHz. A comparison of the physical properties between these films and their bulk ceramics counterparts demonstrates the impact of the aqueous-based electrophoretic deposition (EPD) technique for the preparation of lead-free ferroelectric thick films. This opens the door to the possible development of high-performance, lead-free piezoelectric thick films by a sustainable low-cost process, expanding the applicability of lead-free piezoelectrics.

  7. Origin of discrepancy between electrical and mechanical anomalies in lead-free (K ,Na ) NbO3 -based ceramics

    NASA Astrophysics Data System (ADS)

    Mazuera, A. M.; Silva, P. S.; Rodrigues, A. D.; Pizani, P. S.; Romaguera-Barcelay, Y.; Venet, M.; Algueró, M.

    2016-11-01

    Ferroelectric polymorphic phase coexistence, associated with either the presence of a morphotropic phase boundary or a temperature-driven polymorphic phase transition, is currently acknowledged as the key to high piezoelectric activity and is searched when new perovskite materials are developed, like lead-free alternatives to state-of-the-art Pb (Zr ,Ti ) O3 . This requires characterization tools that allow phase coexistence and transitions to be readily identified, among which measurements of the temperature dependences of Young's modulus and mechanical losses by dynamical mechanical analysis stand out as a powerful technique to complement standard electrical characterizations. We report here the application of this technique to (K1 -xNax )NbO3-based materials, which are under extensive investigation as environmentally friendly high sensitivity piezoelectrics. The elastic anomalies associated with the different phase transitions are identified and are shown to be distinctively shifted in relation to the dielectric ones. The origin of this discrepancy is discussed with the help of temperature-dependent Raman spectroscopy and is proposed to be a characteristic of diffuse phase transitions.

  8. Good Quality Factor in GdMnO3-Doped (K0.5Na0.5)NbO3 Piezoelectric Ceramics

    NASA Astrophysics Data System (ADS)

    Bucur, Raul Alin; Badea, Iuliana; Bucur, Alexandra Ioana; Novaconi, Stefan

    2016-06-01

    (1 - x)(K0.5Na0.5)NbO3 - xGdMnO3 (KNN- xGM) ferroelectric ceramics (0 ≤ x ≤ 5 mol.%) were obtained through a solid state technique. For all the studied compositions, orthorhombic perovskite crystalline structures were obtained at room temperature. GdMnO3 suppresses the grain growth and gives rather homogenous microstructures as the concentration increases. The doped ceramics exhibita good dielectric response, a "hard" ferroelectric behavior and good piezoelectric properties. An improved mechanical quality factor of 1180 and a high Curie temperature T C = 400°C, coupled with k p = 0.426, makes the composition x = 1 mol.% GdMnO3 suitable for lead-free piezoelectric materials for high-power and high-temperature applications.

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

    NASA Technical Reports Server (NTRS)

    Ghaffarian, Reza

    2005-01-01

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

  10. Effects of Ge4+ acceptor dopant on sintering and electrical properties of (K0.5Na0.5)NbO3 lead-free piezoceramics

    NASA Astrophysics Data System (ADS)

    Chen, Kepi; Jiao, Yanlin

    2017-03-01

    Lead-free (K0.5Na0.5)(Nb1- x Ge x )O3 (KNN- xGe, where x = 0-0.01) piezoelectric ceramics were prepared by conventional ceramic processing. The effects of Ge4+ cation doping on the phase compositions, microstructure and electrical properties of KNN ceramics were studied. SEM images show that Ge4+ cation doping improved the sintering and promoted the grain growth of the KNN ceramics. Dielectric and ferroelectric measurements proved that Ge4+ cations substituted Nb5+ ions as acceptors, and the Curie temperature ( T C) shows an almost linear decrease with increasing the Ge4+ content. Combining this result with microstructure observations and electrical measurements, it is concluded that the optimal sintering temperature for KNN- xGe ceramics was 1020°C. Ge4+ doping less than 0.4 mol.%can improve the compositional homogeneity and piezoelectric properties of KNN ceramics. The KNN- xGe ceramics with x = 0.2% exhibited the best piezoelectric properties: piezoelectric constant d 33 = 120 pC/N, planar electromechanical coupling coefficient k p = 34.7%, mechanical quality factor Q m = 130, and tan δ = 3.6%.

  11. Effects of Ge4+ acceptor dopant on sintering and electrical properties of (K0.5Na0.5)NbO3 lead-free piezoceramics

    NASA Astrophysics Data System (ADS)

    Chen, Kepi; Jiao, Yanlin

    2017-01-01

    Lead-free (K0.5Na0.5)(Nb1-x Ge x )O3 (KNN-xGe, where x = 0-0.01) piezoelectric ceramics were prepared by conventional ceramic processing. The effects of Ge4+ cation doping on the phase compositions, microstructure and electrical properties of KNN ceramics were studied. SEM images show that Ge4+ cation doping improved the sintering and promoted the grain growth of the KNN ceramics. Dielectric and ferroelectric measurements proved that Ge4+ cations substituted Nb5+ ions as acceptors, and the Curie temperature (T C) shows an almost linear decrease with increasing the Ge4+ content. Combining this result with microstructure observations and electrical measurements, it is concluded that the optimal sintering temperature for KNN-xGe ceramics was 1020°C. Ge4+ doping less than 0.4 mol.%can improve the compositional homogeneity and piezoelectric properties of KNN ceramics. The KNN-xGe ceramics with x = 0.2% exhibited the best piezoelectric properties: piezoelectric constant d 33 = 120 pC/N, planar electromechanical coupling coefficient k p = 34.7%, mechanical quality factor Q m = 130, and tanδ = 3.6%.

  12. Enhanced torsional actuation and stress coupling in Mn-modified 0.93(Na0.5Bi0.5TiO3)-0.07BaTiO3 lead-free piezoceramic system

    PubMed Central

    Berik, Pelin; Maurya, Deepam; Kumar, Prashant; Kang, Min Gyu; Priya, Shashank

    2017-01-01

    Abstract This paper is concerned with the development of a piezoelectric d 15 shear-induced torsion actuator made of a lead-free piezoceramic material exhibiting giant piezoelectric shear stress coefficient (e 15) and piezoelectric transverse shear actuation force comparable to that of lead-based shear-mode piezoceramics. The Mn-modified 0.93(Na0.5Bi0.5TiO3)-0.07BaTiO3 (NBT-BT-Mn) composition exhibited excellent properties as a torsional transducer with piezoelectric shear stress coefficient on the order of 11.6 C m–2. The torsional transducer, consisting of two oppositely polarized NBT-BT-Mn d 15 mode piezoceramic shear patches, provided a rate of twist of 0.08 mm m–1 V–1 under quasi-static 150 V drive. The high value of piezoelectric shear d 15 coefficient in NBT-BT-Mn sample further demonstrated its potential in practical applications. These results confirm that the lead-free piezoceramics can be as effective as their lead-based counterparts. PMID:28179958

  13. Enhanced torsional actuation and stress coupling in Mn-modified 0.93(Na0.5Bi0.5TiO3)-0.07BaTiO3 lead-free piezoceramic system

    DOE PAGES

    Berik, Pelin; Maurya, Deepam; Kumar, Prashant; ...

    2017-01-09

    This paper is concerned with the development of a piezoelectric d15 shear-induced torsion actuator made of a lead-free piezoceramic material exhibiting giant piezoelectric shear stress coefficient (e15) and piezoelectric transverse shear actuation force comparable to that of leadbased shear-mode piezoceramics. The Mn-modified 0.93(Na0.5Bi0.5TiO3)-0.07BaTiO3 (NBT-BTMn) composition exhibited excellent properties as a torsional transducer with piezoelectric shear stress coefficient on the order of 11.6 C m–2. The torsional transducer, consisting of two oppositely polarized NBT-BT-Mn d15 mode piezoceramic shear patches, provided a rate of twist of 0.08 mm m–1 V–1 under quasi-static 150 V drive. The high value of piezoelectric shear d15more » coefficient in NBT-BT-Mn sample further demonstrated its potential in practical applications. Lastly, these results confirm that the lead-free piezoceramics can be as effective as their lead-based counterparts.« less

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

    NASA Astrophysics Data System (ADS)

    Zhou, Bite

    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

  15. Magnetoelectric coupling effect in lead-free Bi4Ti3O12/CoFe2O4 composite films derived from chemistry solution deposition

    NASA Astrophysics Data System (ADS)

    Tang, Zhehong; Chen, Jieyu; Bai, Yulong; Zhao, Shifeng

    2016-08-01

    Lead-free magnetoelectric composite films combining Bi4Ti3O12 and CoFe2O4 were synthesized by chemical solution deposition on Pt (100)/Ti/SiO2/Si substrate. Morphological and electrical domain structure, ferroelectric, leakage, dielectric, piezoelectric, magnetic and magnetoelectric properties were investigated for Bi4Ti3O12/CoFe2O4 composite films. Well-defined interfaces between Bi4Ti3O12 and CoFe2O4 film layers and electrical domain structure were observed. The composite films show the coexistence of ferroelectric and ferromagnetic orders at room temperature. Larger piezoelectric coefficient and magnetization are obtained for the composite films, which is contributed to the magnetoelectric effect since it originates from the interface coupling through mechanical strain transfer. This work presents a feasible way to modulate the magnetoelectric coupling in ferromagnetic/ferroelectric composite films for developing lead-free micro-electro-mechanical system and information storage devices.

  16. Piezoelectric Film.

    ERIC Educational Resources Information Center

    Garrison, Steve

    1992-01-01

    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)

  17. NASA-DoD Lower Process Temperature Lead-Free Solder Project Overview

    NASA Technical Reports Server (NTRS)

    Kessel, Kurt R.

    2014-01-01

    This project is a follow-on effort to the Joint Council on Aging AircraftJoint Group on Pollution Prevention (JCAAJG-PP) Pb-free Solder Project and NASA-DoD Lead-Free Electronics Project which were the first projects to test the reliability of Pb-free solder joints against the requirements of the aerospace and military community. This effort would continue to build on the results from the JCAAJG-PP Lead-Free Solder Project and NASA-DoD Lead-Free Electronics Project while focusing on a particular failure mechanism currently plaguing Pb-free assemblies, pad cratering.The NASA-DoD Lead-Free Electronics Project confirmed that pad cratering is one of the dominant failure modes that occur in various board level reliability tests, especially under dynamic loading. Pad Cratering is a latent defect that may occur during assembly, rework, and post assembly handling and testing.

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

    PubMed

    Thomas, Vernon George

    2013-10-01

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

  19. Mechanical properties of metal-core piezoelectric fiber

    NASA Astrophysics Data System (ADS)

    Sato, Hiroshi; Nagamine, Masaru

    2005-05-01

    In the previous conference, we produced a new metal core-containing piezoelectric ceramics fiber by the hydrothermal method and extrusion method. The insertion of metal core is significant in view of its greater strength than ceramics materials, and electrodes are not required in the fiber's sensor and actuator applications. A new smart board was designed by mounting these piezoelectric fibers onto the surface of a CFRP composite. After that, this board is able to use this board to a sensor, actuator and vibration suppression. In this paper, we measured s mechanical properties of metal core piezoelectric fiber. We examined the tension test of a piezo-electric fiber, and measured the Young's modulus and breaking strength. Moreover, the expansion in the fiber unit was measured, and the displacement of the direction of d31 was measured. In addition, a piezo-electric fiber that used lead free material (BNT-BT-BKT) to correspond to environmental problems in recent years was made.

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

    PubMed

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

    2014-07-14

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

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

    PubMed

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

    2008-05-01

    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.

  2. Glory of piezoelectric perovskites

    PubMed Central

    Uchino, Kenji

    2015-01-01

    This article reviews the history of piezoelectric perovskites and forecasts future development trends, including Uchino’s discoveries such as the Pb(Mg1/3Nb2/3)O3–PbTiO3 electrostrictor, Pb(Zn1/3Nb2/3)O3–PbTiO3 single crystal, (Pb, La)(Zr, Ti)O3 photostriction, and Pb(Zr, Ti)O3–Terfenol magnetoelectric composites. We discuss five key trends in the development of piezomaterials: performance to reliability, hard to soft, macro to nano, homo to hetero, and single to multi-functional. PMID:27877827

  3. 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)

    Sadiq, Muhammad

    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.

  4. Piezoelectric transducer

    NASA Technical Reports Server (NTRS)

    Conragan, J.; Muller, R. S.

    1970-01-01

    Transducer consists of a hybrid thin film and a piezoelectric transistor that acts as a stress-sensitive device with built-in gain. It provides a stress/strain transducer that incorporates a signal amplification stage and sensor in a single package.

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

    PubMed Central

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

    2014-01-01

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

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

    DOEpatents

    Dixon, George P.; Martin, Joe A.; Thompson, Don

    1998-01-01

    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.

  7. High-Performance Lead-Free Piezoceramics with High Curie Temperatures.

    PubMed

    Lee, Myang Hwan; Kim, Da Jeong; Park, Jin Su; Kim, Sang Wook; Song, Tae Kwon; Kim, Myong-Ho; Kim, Won-Jeong; Do, Dalhyun; Jeong, Il-Kyoung

    2015-11-18

    A bismuth ferrite and barium titanate solid solution compound can achieve good piezoelectric properties with a high Curie temperature when fabricated with low-temperature sintering followed by a water-quenching process, with no complicated grain alignment processes performed. By adding the super-tetragonal bismuth gallium oxide to the compound, the piezoelectric properties are as good as those of lead zirconate titanate ceramics.

  8. Plausible domain configurations and phase contents in two- and three-phase BaTiO3-based lead-free ferroelectrics

    NASA Astrophysics Data System (ADS)

    Topolov, Vitaly Yu; Brajesh, Kumar; Ranjan, Rajeev; Panich, Anatoly E.

    2017-02-01

    We have carried out a comparative study of plausible non-180° domain configurations in the two- and three-phase states of lead-free ferroelectrics Ba(Ti1-x Zr x )O3 (0.02  ⩽  x  ⩽  0.08) and (Ba0.85Ca0.15)(Ti0.90Zr0.10)O3, respectively, using the elastic matching approach. The phase contents and stress-relief conditions in Ba(Ti0.93Zr0.07)O3 and (Ba0.85Ca0.15)(Ti0.90Zr0.10)O3 strongly depend on domain types in the rhombohedral R3m phase, whereas domains of the orthorhombic Amm2 phase influence two-phase states in Ba(Ti0.98Zr0.02)O3. Changes in unit-cell parameters of (Ba0.85Ca0.15)(Ti0.90Zr0.10)O3 at poling lead to the complete stress relief in three-phase (P4mm  +  Amm2  +  R3m) structures by increasing the volume fraction of the R3m phase. A link between the heterophase/domain structures and high piezoelectric activity in (Ba0.85Ca0.15)(Ti0.90Zr0.10)O3 is discussed. Based on our results, we state that equal or almost equal volume fractions of the domain types at the three-phase coexistence in (Ba0.85Ca0.15). .(Ti0.90Zr0.10)O3 can lead to an enhanced contribution from domain-wall displacements and therefore, to the large piezoelectric response in this important lead-free ferroelectric compound.

  9. 25 MHz ultrasonic transducers with lead-free piezoceramic, 1-3 PZT fiber-epoxy composite, and PVDF polymer active elements.

    PubMed

    Jadidian, Bahram; Hagh, Nader Marandian; Winder, Alan A; Safari, Ahmad

    2009-02-01

    This paper presents the fabrication and characterization of single-element ultrasonic transducers whose active elements are made of lead-free piezoceramic, 1-3 PZT/polymer composite and PVDF film. The lead free piezoelectric KNNLT- LS(K(0.44)Na(0.52)Li(0.04))(Nb(0.84)Ta(0.10)S(0.06)b)O(3) powders and ceramics were prepared under controlled humidity and oxygen flow rate during sintering. Due to its moderate longitudinal piezoelectric charge coefficient (175 pC/N) and k(t) of 0.50, the KNN-LT-LS composition may be a good candidate for high frequency transducer applications. PZT fibers with 25 microm diameter formed by the viscose suspension spinning process were incorporated into epoxy to fabricate 1-3 composites with the averaged k(t) = 0.64 and d(33) = 400 pC/N. Using KNN-LS-LT ceramic, 1-3 PZT fiber composite, and PVDF film, 3 different unfocused single element transducers with center frequencies of 25 MHz were fabricated. The acoustic characterization of the transducers demonstrated that wideband and low insertion loss could be obtained employing KNN-LS-LT ceramic. The -6 dB bandwidth and insertion loss were 70% and -21 dB, respectively. In comparison, the insertion loss of the ceramic transducer was much smaller than those made with 1-3 composite and PVDF film. This was attributed to closer electrical impedance match to 50 ohm and higher thickness coupling coefficient of the ceramic transducer.

  10. Ultrahigh Energy Storage Performance of Lead-Free Oxide Multilayer Film Capacitors via Interface Engineering.

    PubMed

    Sun, Zixiong; Ma, Chunrui; Liu, Ming; Cui, Jin; Lu, Lu; Lu, Jiangbo; Lou, Xiaojie; Jin, Lei; Wang, Hong; Jia, Chun-Lin

    2017-02-01

    Ultrahigh energy storage density of 52.4 J cm(-3) with optimistic efficiency of 72.3% is achieved by interface engineering of epitaxial lead-free oxide multilayers at room temperature. Moreover, the excellent thermal stability of the performances provides solid basis for widespread applications of the thin film systems in modern electronic and power modules in harsh working environments.

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

    EPA Science Inventory

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

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

    NASA Technical Reports Server (NTRS)

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

    2003-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2009-12-01

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

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

    NASA Technical Reports Server (NTRS)

    Brown, Christina

    2004-01-01

    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.

  15. Microcantilever Fracture Testing of Intermetallic Cu3Sn in Lead-Free Solder Interconnects

    NASA Astrophysics Data System (ADS)

    Philippi, Bastian; Matoy, Kurt; Zechner, Johannes; Kirchlechner, Christoph; Dehm, Gerhard

    2017-01-01

    Driven by legislation and the abolishment of harmful and hazardous lead-containing solders, lead-free replacement materials are in continuous development. Assessment of the mechanical properties of intermetallic phases such as Cu3Sn that evolve at the interface between solder and copper metalization is crucial to predict performance and meet the high reliability demands in typical application fields of microelectronics. While representative material parameters and fracture properties are required to assess mechanical behavior, indentation-based testing produces different results depending on the sample type. In this work, focused ion beam machined cantilevers were used to unravel the impact of microstructure on the fracture behavior of Sn-Ag-Cu lead-free solder joints. Fracture testing on notched cantilevers showed brittle fracture for Cu3Sn. Unnotched samples allowed measurement of the fracture stress, to estimate the critical defect size in unnotched Cu3Sn microcantilevers.

  16. Wetting Kinetics of Eutectic Lead and Lead-Free Solders: Spreading over the Cu Surface

    NASA Astrophysics Data System (ADS)

    Zhao, Hui; Nalagatla, Dinesh Reddy; Sekulic, Dusan P.

    2009-02-01

    Wetting kinetics of Sn, eutectic Sn-Ag, eutectic Sn-Cu, and eutectic Pb-Sn was studied using real-time in situ monitoring of the triple-line movement, facilitated by a hot-stage microscopy system under a controlled atmosphere. Significantly different kinetics of lead versus lead-free solders is documented. In case of the eutectic lead solder, four characteristic spreading stages were identified. Spreading of lead-free solders features two stages with a sharp change of the spreading rate at the early stages of rather insignificant spreading. Scanning electron microscopy and energy-dispersive x-ray spectroscopy analysis of the resolidified solder surface within a halo region is discussed.

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

    PubMed

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

    2011-02-01

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

  18. Microcantilever Fracture Testing of Intermetallic Cu3Sn in Lead-Free Solder Interconnects

    NASA Astrophysics Data System (ADS)

    Philippi, Bastian; Matoy, Kurt; Zechner, Johannes; Kirchlechner, Christoph; Dehm, Gerhard

    2017-03-01

    Driven by legislation and the abolishment of harmful and hazardous lead-containing solders, lead-free replacement materials are in continuous development. Assessment of the mechanical properties of intermetallic phases such as Cu3Sn that evolve at the interface between solder and copper metalization is crucial to predict performance and meet the high reliability demands in typical application fields of microelectronics. While representative material parameters and fracture properties are required to assess mechanical behavior, indentation-based testing produces different results depending on the sample type. In this work, focused ion beam machined cantilevers were used to unravel the impact of microstructure on the fracture behavior of Sn-Ag-Cu lead-free solder joints. Fracture testing on notched cantilevers showed brittle fracture for Cu3Sn. Unnotched samples allowed measurement of the fracture stress, to estimate the critical defect size in unnotched Cu3Sn microcantilevers.

  19. NASA-DoD Lead-Free Electronics Project: Vibration Test

    NASA Technical Reports Server (NTRS)

    Woodrow, Thomas A.

    2010-01-01

    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.

  20. Conceptual design for 12 V "lead-free" accumulators for automobile and stationary applications

    NASA Astrophysics Data System (ADS)

    Ariyoshi, Kingo; Ohzuku, Tsutomu

    Conceptual design for 12 V lead-free accumulators is presented using basic research results on lithium insertion materials. Among possible materials, Li[Li 1/3Ti 5/3]O 4 is selected for a negative-electrode material, and Li[Ni 1/2Mn 3/2]O 4, LiMn 2O 4, LiCo 1/3Ni 1/3Mn 1/3O 2, and LiFePO 4 are specifically considered as positive-electrode materials. Combination of these materials with Li[Li 1/3Ti 5/3]O 4 gives a 2, 2.5 or 3 V lithium-ion battery. Series connection of such a lithium-ion battery makes 12 V lead-free accumulators possible. Characteristic features of the lead-free accumulators are discussed in terms of energy density for deep charge and discharge cycles, power density for short period of time, material economy, environmental friendliness, and safety compared with those of lead-acid batteries currently hold a position in automobile, large uninterruptible power supply, and off-grid solar home systems.

  1. Lead-Free Double-Base Propellant for the 2.75 Inch Rocket Motor

    NASA Technical Reports Server (NTRS)

    Magill, B. T.; Nauflett, G. W.; Furrow, K. W.

    2000-01-01

    The current MK 66 2.75 inch Rocket Motor double-base propellant contains the lead-based ballistic modifier LC-12-15 to achieve the desired plateau and mesa burning rate characteristics. The use of lead compounds poses a concern for the environment and for personal safety due to the metal's toxic nature when introduced into the atmosphere by propellant manufacture, rocket motor firing, and disposal. Copper beta-resorcylate (copper 2,4-di-hydroxy-benzoate) was successfully used in propellant as a simple modifier in the mid 1970's. This and other compounds have also been mixed with lead salts to obtain more beneficial ballistic results. Synthesized complexes of lead and copper compounds soon replaced the mixtures. The complexes incorporate the lead, copper lack of organic liquids, which allows for easier propellant processing. About ten years ago, the Indian Head Division, Naval Surface Warfare Center (NSWC), initiated an effort to develop a lead-free propellant for use in missile systems. Several lead-free propellant candidate formulations were developed. About five years ago, NSWC, in conjunction with Alliant Techsystems, Radford Army Ammunition Plant, continued ballistic modifier investigations. A four component ballistic modifier system without lead for double-base propellants that provide adequate plateau and mesa burn rate characteristics was developed and patented. The ballistic modifier's system contains bismuth subsalicylate, 1.5 percent; copper salicylate, 1.0 percent, copper stannate, 0.77 percent; and carbon black, 0.1 percent. Action time and impulse data obtained through multiple static firings indicate that the new lead-free double-base propellant, while not a match for NOSIH-AA-2, will be a very suitable replacement in the 2.75 inch Rocket Motor. Accelerated aging of the double-base propellant containing the lead-free ballistic modifier showed that it had a much higher rate of stabilizer depletion than the AA-2. A comprehensive study showed that an

  2. Unprecedented Electro-Optic Performance in Lead-Free Transparent Ceramics.

    PubMed

    Dupuy, Alexander D; Kodera, Yasuhiro; Garay, Javier E

    2016-09-01

    A high-performance lead-free electro-optic (EO) transparent material is introduced and used in an EO device operating up to 10 kHz. The BZT-BCT ceramic, named as BXT, has an effective DC EO coefficient, rc = 530 pm V(-1) , which is higher than state-of-the-art materials such as LiNbO3 . The high EO response can be leveraged for miniaturization and/or reduction of the operating voltage of EO devices.

  3. Voiding in lead-free soldering of components with large solder pads

    NASA Astrophysics Data System (ADS)

    Dziurdzia, Barbara; Mikołajek, Janusz

    2016-12-01

    The paper presents the quantification of void formation in lead-free solder joints underneath bottom terminated components (BTCs) through X-ray inspection. Experiments were designed to investigate how void formation is affected by using vacuum in reflow soldering on the example of light emitted diode (LED) packages on metal core printed circuit boards (PCBs). Convection and vapour phase reflow soldering were used for LED assembly. X-ray inspection system analyzed the statistical distribution, mean value, standard deviation and process capability value Cpk of thermal pads coverage for various technological versions of LEDs.

  4. Correlation of Bulk Dielectric and Piezoelectric Properties to the Local Scale Phase Transformations, Domain Morphology, and Crystal Structure Modified

    SciTech Connect

    Priya, Shashank; Viehland, Dwight

    2014-12-14

    Three year program entitled “Correlation of bulk dielectric and piezoelectric properties to the local scale phase transformations, domain morphology, and crystal structure in modified lead-free grain-textured ceramics and single crystals” was supported by the Department of Energy. This was a joint research program between D. Viehland and S. Priya at Virginia Tech. Single crystal and textured ceramics have been synthesized and characterized. Our goals have been (i) to conduct investigations of lead-free piezoelectric systems to establish the local structural and domain morphologies that result in enhanced properties, and (ii) to synthesize polycrystalline and grain oriented ceramics for understanding the role of composition, microstructure, and anisotropy

  5. Evaluation of Bulk Mechanical Properties of Selected Lead-Free Solders in Tension and in Shear

    NASA Astrophysics Data System (ADS)

    Devaki Rani, S.; Murthy, G. S.

    2013-08-01

    Lead-free solders are fast emerging as better alternatives to Sn-Pb solders. The reliability of a soldered joint to withstand imposed stresses in an assembly is decided by its mechanical properties. The present work is about the investigation of tensile and shear properties of four binary eutectic alloys Sn-3.5Ag, Sn-58Bi, Sn-0.7Cu, Sn-9Zn and a ternary alloy Sn-57Bi-1.3Zn in comparison with conventional Sn-38Pb alloy. It is observed that the lead-free solders have better mechanical properties than the latter. SEM studies of tensile and shear fracture show ductile dimples circular in tension and parabolic in shear modes supporting the mechanical behavior of the alloys investigated. Eutectic alloys Sn-Ag, Sn-Zn, and Sn-Cu form potential substitutes for Sn-Pb for electronic interconnects exposed to high temperatures, while Sn-Bi and Sn-Bi-Zn are attractive alternatives in addressing the need of lower processing temperatures in printed circuit boards and other applications.

  6. Wettability of electroless Ni in the under bump metallurgy with lead free solder

    NASA Astrophysics Data System (ADS)

    Young, Bi-Lian; Duh, Jenq-Gong; Chiou, Bi-Shiou

    2001-05-01

    This study investigates the wettability of several lead-free solders, including Sn, Sn-Ag, and Sn-Bi, on electroless Ni (EN) with various phosphorus content. The role of phosphorus on solder wettability is studied. Microstructure evolution in the lead-free solder/EN joint is investigated with the aid of electron probe microanalyzer (EPMA) to relate metallurgical reactions between the solder and the EN. The SN solder exhibits better wettability on EN, while the Si-Bi solder has a larger contact angle. Wettability degrades as the phosphorus content in EN decreases. The dependence of wetting angle on the phosphorous content can be attributed to the surface roughness and density of EN, along with the interfacial reaction between the solders and EN. An EPMA analysis reveals the presence of a Sn-Bi-Ni-P solid solution at the interface of solder/EN joints due to the interdiffusion of major constituent Ni and Sn. The interaction zone of the solid solution increases with increasing temperature. Wettability of Pb-free solders on EN degrades with the presence of NiO due to oxidation or the existence of Ni3P due to precipitation after annealing. For an adequate wetting behavior in the Sn (Sn-Bi, Sn-Ag)/EN joint, EN deposited with phosphorus contents in the range of 9 to 12 wt% is suggested.

  7. Intermetallic phase detection in lead-free solders using synchrotron x-ray diffraction

    NASA Astrophysics Data System (ADS)

    Jackson, Gavin J.; Lu, Hua; Durairaj, Raj; Hoo, Nick; Bailey, Chris; Ekere, Ndy N.; Wright, Jon

    2004-12-01

    The high-intensity, high-resolution x-ray source at the European Synchrotron Radiation Facility (ESRF) has been used in x-ray diffraction (XRD) experiments to detect intermetallic compounds (IMCs) in lead-free solder bumps. The IMCs found in 95.5Sn3.8Ag0.7Cu solder bumps on Cu pads with electroplated-nickel immersion-gold (ENIG) surface finish are consistent with results based on traditional destructive methods. Moreover, after positive identification of the IMCs from the diffraction data, spatial distribution plots over the entire bump were obtained. These spatial distributions for selected intermetallic phases display the layer thickness and confirm the locations of the IMCs. For isothermally aged solder samples, results have shown that much thicker layers of IMCs have grown from the pad interface into the bulk of the solder. Additionally, the XRD technique has also been used in a temperature-resolved mode to observe the formation of IMCs, in situ, during the solidification of the solder joint. The results demonstrate that the XRD technique is very attractive as it allows for nondestructive investigations to be performed on expensive state-of-the-art electronic components, thereby allowing new, lead-free materials to be fully characterized.

  8. Study on Dynamic Failure Model of Lead-Free Solders Using Shpb Techniques

    NASA Astrophysics Data System (ADS)

    Niu, Xiaoyan; Yuan, Guozheng; Li, Zhigang; Shu, Xuefeng

    The dynamic compressive properties of 96.3Sn3Ag0.7Cu and 99.3Sn0.7Cu solders were studied by means of a split Hopkinson pressure bar at strain rates ranging from 500 to 2000 s-1. Tests were conducted at room temperature and under uniaxial compressive conditions. Eutectic SnPb solders were used as the reference. From the data of tests, it was found that yield strength and flow stress increased remarkably with the increase of strain rate. On logarithmic scales, the yield strength increased linearly with strain rate. These lead-free solders revealed certain visco-plastic behavior and strain rate sensitivity, which predicted using Johnson-Cook material model. Related parameters in the model were determined from the experiment. Compared with the typical Pb-containing solder Sn63Pb37, these lead-free solders showed some fine properties and could substitute some Pb-containing solder alloys in microelectronic components packaging and interconnects.

  9. Assessment of circuit board surface finishes for electronic assembly with lead-free solders

    SciTech Connect

    Ray, U.; Artaki, I.; Finley, D.W.; Wenger, G.M.; Pan, T.; Blair, H.D.; Nicholson, J.M.; Vianco, P.T.

    1996-10-01

    The suitability of various metallic printed wiring board surface finishes was assessed for new technology applications that incorporate assembly with Lead-free solders. The manufacture of a lead-free product necessitates elimination of lead (Pb) from the solder, the circuit board as well as the component lead termination. It is critical however for the selected interconnect Pb-free solder and the corresponding printed wiring board (PWB) and component lead finishes to be mutually compatible. Baseline compatibility of select Pb-free solders with Pb containing PWB surface finish and components was assessed. This was followed by examining the compatibility of the commercially available CASTIN{trademark} (SnAgCuSb) Pb-free solder with a series of PWB metallic finishes: Ni/Au, Ni/Pd, and Pd/Cu. The compatibility was assessed with respect to assembly performance, solder joint integrity and long term attachment reliability. Solder joint integrity and mechanical behavior of representative 50 mil pitch 20I/O SOICs was determined before and after thermal stress. Mechanical pull test studies demonstrated that the strength of SnAgCuSb solder interconnections is notably greater than that of SnPb interconnections.

  10. Enhancing electromechanical properties of lead-free ferroelectrics with bilayer ceramic/ceramic composites.

    PubMed

    Ayrikyan, Azatuhi; Rojas, Virginia; Molina-Luna, Leopoldo; Acosta, Matias; Koruza, Jurij; Webber, Kyle G

    2015-06-01

    The macroscopic electromechanical behavior of lead-free bilayer composites was characterized at room temperature. One layer consisted of a nonergodic relaxor, (Bi1/2Na1/2)TiO3-7BaTiO3, with an electric-field-induced longrange ferroelectric order, whereas the other is understood to be an ergodic relaxor [(Bi1/2Na1/2)TiO3-25SrTiO3] that undergoes a reversible electric-field-induced macroscopic nonpolar-to-polar transition. Microstructural evidence of a bilayer with low diffusion between the two components is also demonstrated. By taking advantage of the different macroscopic strain- and polarization-electric-field responses of the two constituents, internal mechanical and electrical fields can be developed that enhance the unipolar strain over that expected by a rule of mixtures approximation, thereby improving the properties needed for application of such materials to actuator systems. It is possible through further tailoring of the volume fractions and macroscopic properties of the constituents to optimize the electromechanical properties of multilayer lead-free ferroelectrics.

  11. Sn-Pb and lead free solders containing active carbon particles

    NASA Astrophysics Data System (ADS)

    Talas, S.; Gökçe, B.; Çakmakkaya, M.

    2016-08-01

    Upon the legislations issued by the governmental agencies, many companies are in effort of using lead free solders for their electronic products. Many researchers have also focused on lead free solders and determined their physical properties to the merit of their desired strength and conductivity which turns out to be a potentially advantageous after all. The addition of nano particles into the solder alloys has been attempted to investigate the property change caused by such addition from which a main outcome was a limited improved mechanical and physical properties such as lowering the melting temperature. In this study, the addition of nano active carbon particles to Pb-Sn and Pb-free solder alloys were made and characterization studies were conducted to determine their basic properties such as electrical conductivity, microstructural study and also phase transformations. The results indicate that the addition of active carbon particles brings about a change in thermal properties more markedly than other properties with respect to the amount of addition.

  12. Cosmic ray modulation studies with Lead-Free Gulmarg Neutron Monitor

    NASA Astrophysics Data System (ADS)

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

    2014-02-01

    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.

  13. Piezoelectric thin films: an integrated review of transducers and energy harvesting

    NASA Astrophysics Data System (ADS)

    Khan, Asif; Abas, Zafar; Kim, Heung Soo; Oh, Il-Kwon

    2016-05-01

    Piezoelectric thin films offer a number of advantages in various applications, such as high energy density harvesters, a wide dynamic range, and high sensitivity sensors, as well as large displacement and low power consumption actuators. This review covers the available material forms and applications of piezoelectric thin films: lead zirconate titanate (PZT)-based thin films, lead-free piezoelectric thin films, piezopolymer films, cellulose-based electroactive paper (EAPap), and many other thin films used for electromechanical transduction. The electromechanical properties and performances of piezoelectric films are compared and their suitability for particular applications are reported. The key ideas of piezoelectric thin films are reviewed and discussed for sensory and actuation systems, energy harvesting, and medical and acoustic transducers. In the last section, an insight into the future outlook and possibilities for thin film-based devices and their integration into real-world applications is presented.

  14. Temperature Evolution of Physical Properties of BaTi0.9(Nb0.5Yb0.5)0.1O3 Lead-Free Ceramic

    NASA Astrophysics Data System (ADS)

    Abdelkafi, Z.; Abdelmoula, N.; Khemakhem, H.

    2016-11-01

    BaTi0.9(Nb0.5Yb0.5)0.1O3 lead-free ceramic was prepared by a solid-state reaction method. The structure of BaTi0.9(Nb0.5Yb0.5)0.1O3 has been characterized by means of x-ray diffraction, showing the coexistence of cubic (31.1%) and tetragonal (68.9%) phases at room temperature. Dielectric spectroscopy shows that BaTi0.9(Nb0.5Yb0.5)0.1O3 composition sintered at 1380°C exhibits a relaxor behavior with a weak diffuse phase transition obeying a Lorentz-type quadratic relationship. The ferroelectric-paraelectric phase transition T C decreased from 420 K for BaTiO3 to 284 K for BaTi0.9(Nb0.5Yb0.5)0.1O3. The dielectric loss of this ceramic was <0.09 over a wide temperature range (<400 K). The temperature behavior of the main piezoelectric parameters, such as the piezoelectric coefficient d 31 and the electromechanical coupling factor k p, was investigated. d 31 sets a maximum about 32.5 pC/N at temperature of 220 K. Nevertheless, k p undergoes more or less important changes between 120 K and 200 K. Over 200 K, k p degrades very rapidly due to the depoling effect deduced from the hysterisis measurements. Dielectric and structural properties of BaTi0.9(Nb0.5Yb0.5)0.1O3 were confirmed by Raman spectroscopy.

  15. Piezoelectric ultrasonic motors

    SciTech Connect

    Wallaschek, J.

    1994-12-31

    Piezoelectric ultrasonic motors are a new type of actuator. They are characterized by high torque at low rotational speed, simple mechanical design and good controllability. They also provide a high holding torque even if no power is applied. Compared to electromagnetic actuators the torque per volume ratio of piezoelectric ultrasonic motors can be higher by an order of magnitude. Recently various types of piezoelectric ultrasonic motors have been developed for industrial applications. This paper describes several types of piezoelectric ultrasonic motors.

  16. "Mighty Worm" Piezoelectric Actuator

    NASA Technical Reports Server (NTRS)

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

    1994-01-01

    "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.

  17. Piezoelectric drive circuit

    DOEpatents

    Treu, C.A. Jr.

    1999-08-31

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

  18. Piezoelectric drive circuit

    DOEpatents

    Treu, Jr., Charles A.

    1999-08-31

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

  19. Electrical properties of (1−x)(Bi{sub 0.5}Na{sub 0.5})TiO{sub 3}–xKNbO{sub 3} lead-free ceramics

    SciTech Connect

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

    2014-05-01

    In this investigation, a simple compound (1−x)(Bi{sub 0.5}Na{sub 0.5})TiO{sub 3}–xKNbO{sub 3} (BNT–xKN, x=0–0.08) lead-free ceramics were synthesized successfully by conventional solid state reaction method. The piezoelectric, dielectric and ferroelectric characteristics of the ceramics were investigated and discussed. The results shows that moderate KN addition can enhance the piezoelectric response without an obvious decline of ferroelectric properties. The largest piezoelectric response is obtained in BNT–0.05KN, whereas largest electric-field-induced strain is obtained in BNT–0.06KN. An effective d{sub 33}{sup eff} of ∼400 pC/N calculated from electric-field-induced strain is obtained in BNT–0.06KN. The present investigation demonstrates that addition KN effectively reduces the depolarization temperature of the BNT–xKN ceramics. The electrical properties of the ceramics are tightly related to their depolarization temperature. - Graphical abstract: Unipolar electric-field-induced strain for the BNT–xKN ceramics. A maximum strain of 0.28% is achieved with a low field in BNT–0.06KN. - Highlights: • Moderate KNbO{sub 3} addition enhances the piezoelectric properties of the ceramics. • A maximum strain of 0.28% is achieved with a low field. • A large piezoelectric response is achieved in 0.95(Bi{sub 0.5}Na{sub 0.5})TiO{sub 3}–0.05KNbO{sub 3}. • The electrical properties are tightly related to the depolarization temperature T{sub d}.

  20. Development and application of a new lead-free steel for making distributor parts of Otto engines

    NASA Astrophysics Data System (ADS)

    Aliev, A. A.

    2012-07-01

    Results of the development and introduction into commercial production of lead-free fine-machining steel to replace the lead-bearing steel AS45G2 for making distributor spindles and cams of automotive Otto engines are presented.

  1. Bonding nature of rare-earth-containing lead-free solders

    NASA Astrophysics Data System (ADS)

    Ramirez, Ainissa G.; Mavoori, Hareesh; Jin, Sungho

    2002-01-01

    The ability of rare-earth-containing lead-free solders to wet and bond to silica was investigated. Small additions of Lu (0.5-2 wt. %) added to eutectic Sn-Ag or Au-Sn solder render it directly solderable to a silicon oxide surface. The bonding is attributed to the migration of the rare-earth element to the solder-silica interface for chemical reaction and the creation of an interfacial layer that contains a rare-earth oxide. It was found that additions of rare-earth materials did not significantly modify the solidification microstructure or the melting point. Such oxide-bondable solders can be useful for assembly of various optical communication devices.

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

    NASA Astrophysics Data System (ADS)

    Anson, Scott J.

    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

  3. Anomalous change in leakage and displacement currents after electrical poling on lead-free ferroelectric ceramics

    NASA Astrophysics Data System (ADS)

    Borkar, Hitesh; Tomar, M.; Gupta, Vinay; Scott, J. F.; Kumar, Ashok

    2015-09-01

    We report the polarization, displacement current, and leakage current behavior of a trivalent nonpolar cation (Al3+) substituted lead free ferroelectric (Na0.46Bi0.46-xAlxBa0.08)TiO3 (NBAT-BT) (x = 0, 0.05, 0.07 and 0.10) electroceramics with tetragonal phase and P4 mm space group symmetry. Almost, three orders of magnitude decrease in leakage current were observed under electrical poling, which significantly improves microstructure, polarization, and displacement current. Effective poling neutralizes the domain pinning, traps charges at grain boundaries and fills oxygen vacancies with free charge carriers in matrix, thus saturated macroscopic polarization in contrast to that in unpoled samples. E-poling changes "bananas" type polarization loops to real ferroelectric loops.

  4. Tuning the electrocaloric enhancement near the morphotropic phase boundary in lead-free ceramics

    NASA Astrophysics Data System (ADS)

    Le Goupil, Florian; McKinnon, Ruth; Koval, Vladimir; Viola, Giuseppe; Dunn, Steve; Berenov, Andrey; Yan, Haixue; Alford, Neil Mcn.

    2016-06-01

    The need for more energy-efficient and environmentally-friendly alternatives in the refrigeration industry to meet global emission targets has driven efforts towards materials with a potential for solid state cooling. Adiabatic depolarisation cooling, based on the electrocaloric effect (ECE), is a significant contender for efficient new solid state refrigeration techniques. Some of the highest ECE performances reported are found in compounds close to the morphotropic phase boundary (MPB). This relationship between performance and the MPB makes the ability to tune the position of the MPB an important challenge in electrocaloric research. Here, we report direct ECE measurements performed on MPB tuned NBT-06BT bulk ceramics with a combination of A-site substitutions. We successfully shift the MPB of these lead-free ceramics closer to room temperature, as required for solid state refrigeration, without loss of the criticality of the system and the associated ECE enhancement.

  5. Tuning the electrocaloric enhancement near the morphotropic phase boundary in lead-free ceramics.

    PubMed

    Le Goupil, Florian; McKinnon, Ruth; Koval, Vladimir; Viola, Giuseppe; Dunn, Steve; Berenov, Andrey; Yan, Haixue; Alford, Neil McN

    2016-06-17

    The need for more energy-efficient and environmentally-friendly alternatives in the refrigeration industry to meet global emission targets has driven efforts towards materials with a potential for solid state cooling. Adiabatic depolarisation cooling, based on the electrocaloric effect (ECE), is a significant contender for efficient new solid state refrigeration techniques. Some of the highest ECE performances reported are found in compounds close to the morphotropic phase boundary (MPB). This relationship between performance and the MPB makes the ability to tune the position of the MPB an important challenge in electrocaloric research. Here, we report direct ECE measurements performed on MPB tuned NBT-06BT bulk ceramics with a combination of A-site substitutions. We successfully shift the MPB of these lead-free ceramics closer to room temperature, as required for solid state refrigeration, without loss of the criticality of the system and the associated ECE enhancement.

  6. Tuning the electrocaloric enhancement near the morphotropic phase boundary in lead-free ceramics

    PubMed Central

    Le Goupil, Florian; McKinnon, Ruth; Koval, Vladimir; Viola, Giuseppe; Dunn, Steve; Berenov, Andrey; Yan, Haixue; Alford, Neil McN.

    2016-01-01

    The need for more energy-efficient and environmentally-friendly alternatives in the refrigeration industry to meet global emission targets has driven efforts towards materials with a potential for solid state cooling. Adiabatic depolarisation cooling, based on the electrocaloric effect (ECE), is a significant contender for efficient new solid state refrigeration techniques. Some of the highest ECE performances reported are found in compounds close to the morphotropic phase boundary (MPB). This relationship between performance and the MPB makes the ability to tune the position of the MPB an important challenge in electrocaloric research. Here, we report direct ECE measurements performed on MPB tuned NBT-06BT bulk ceramics with a combination of A-site substitutions. We successfully shift the MPB of these lead-free ceramics closer to room temperature, as required for solid state refrigeration, without loss of the criticality of the system and the associated ECE enhancement. PMID:27312287

  7. Electrocaloric enhancement near the morphotropic phase boundary in lead-free NBT-KBT ceramics

    NASA Astrophysics Data System (ADS)

    Le Goupil, Florian; Bennett, James; Axelsson, Anna-Karin; Valant, Matjaz; Berenov, Andrey; Bell, Andrew J.; Comyn, Tim P.; Alford, Neil McN.

    2015-10-01

    The electrocaloric effects (ECEs) of the morphotropic phase boundary (MPB) composition 0.82(Na0.5Bi0.5)TiO3-0.18(K0.5Bi0.5)TiO3 (NBT-18KBT) are studied by direct measurements. The maximum ECE ΔTmax = 0.73 K is measured at 160 °C under 22 kV/cm. This corresponds to an ECE responsivity (ΔT/ΔE) of 0.33 × 10-6 K m/V, which is comparable with the best reported values for lead-free ceramics. A comparison between the direct and indirect ECE measurements shows significant discrepancies. The direct measurement of both positive and negative electrocaloric effect confirms the presence of numerous polar phases near the MPB of NBT-based materials and highlights their potential for solid-state cooling based on high field-induced entropy changes.

  8. Assessment of the Radiation Attenuation Properties of Several Lead Free Composites by Monte Carlo Simulation

    PubMed Central

    Kazempour, M.; Saeedimoghadam, M.; Shekoohi Shooli, F.; Shokrpour, N.

    2015-01-01

    Background: In diagnostic radiology lead apron, are usually used to protect patients and radiology staff against ionizing radiation. Lead apron is a desirable shield due to high absorption and effective attenuation of x-ray photons in the diagnostic radiology range. Objective: Although lead aprons have good radiation protection properties, in recent years, researchers have been looking for alternative materials to be used instead of lead apron because of some problems derived from lead-content of aprons. Because of its lead-content, these radiation protection garments are so heavy and uncomfortable for the staff to wear, particularly in long-time uses. In addition, lead is a toxic element and its disposal is associated with environmental and human-health hazards. Method: In this study, several new combinations of lead free materials ((W-Si), (W-Sn-Ba-EPVC ), (W-Sn-Cd-EPVC)) have been investigated in the energy range of diagnostic radiology in two geometries: narrow and broad beam. Geometries of the radiation attenuation characteristics of these materials was assessed in 40, 60, 90 and 120 kVp and the results compared with those of some lead-containing materials ((Pb-Si), (Pb-EPVC)). Results: Lead shields still provide better protection in low energies (below 40 kVp). Combination of W-Sn-Cd-EPVC has shown the best radiation attenuation features in 60 and 90 kVp and the composition of (W-Sn-Ba-EPVC) represents the best attenuation in 120 kVp, even better than previously mentioned lead- containing composites. Conclusion: Lead free shields are completely effective for protection against X-ray energies in the range of 60 to 120 kVp. PMID:26157732

  9. A novel method for direct solder bump pull testing using lead-free solders

    NASA Astrophysics Data System (ADS)

    Turner, Gregory Alan

    This thesis focuses on the design, fabrication, and evaluation of a new method for testing the adhesion strength of lead-free solders, named the Isotraction Bump Pull method (IBP). In order to develop a direct solder joint-strength testing method that did not require customization for different solder types, bump sizes, specific equipment, or trial-and-error, a combination of two widely used and accepted standards was created. First, solder bumps were made from three types of lead free solder were generated on untreated copper PCB substrates using an in-house fabricated solder bump-on-demand generator, Following this, the newly developed method made use of a polymer epoxy to encapsulate the solder bumps that could then be tested under tension using a high precision universal vertical load machine. The tests produced repeatable and predictable results for each of the three alloys tested that were in agreement with the relative behavior of the same alloys using other testing methods in the literature. The median peak stress at failure for the three solders tested were 2020.52 psi, 940.57 psi, and 2781.0 psi, and were within one standard deviation of the of all data collected for each solder. The assumptions in this work that brittle fracture occurred through the Intermetallic Compound layer (IMC) were validated with the use of Energy-Dispersive X-Ray Spectrometry and high magnification of the fractured surface of both newly exposed sides of the test specimens. Following this, an examination of the process to apply the results from the tensile tests into standard material science equations for the fracture of the systems was performed..

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

    PubMed Central

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

    2015-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-02-01

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

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

    PubMed

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

    2015-02-16

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

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

    NASA Astrophysics Data System (ADS)

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

    2006-09-01

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

  14. Preparation and characterization of Sr0.5Ba0.5Nb2O6 glass-ceramic on piezoelectric properties

    NASA Astrophysics Data System (ADS)

    Shan, Jiang; Xuan-Ming, Wang; Jia-Yu, Li; Yong, Zhang; Tao, Zheng; Jing-Wen, Lv

    2016-03-01

    We studied the influence of heat treatment time on the optical, thermal, electrical, and mechanical properties of strontium barium niobate (Sr1-xBaxNb2O6 hereafter SBN) piezoelectric glass-ceramics with tungsten bronze-type structure, which have good piezoelectric properties and are important lead-free piezoelectric materials. We found that the best heat treatment time is 4 h. The properties of the prepared materials are better than that of SBN ceramics and the glass-ceramic growth is faster than the SBN crystal when the heat treatment time of the SBN piezoelectric glass-ceramic is controlled, reducing the preparation costs greatly.

  15. Piezoelectrically assisted ultrafiltration

    SciTech Connect

    Ahner, N.; Gottschlich, D.; Narang, S.; Roberts, D.; Sharma, S.; Ventura, S.

    1993-01-01

    The authors have demonstrated the feasibility of using piezoelectrically assisted ultrafiltration to reduce membrane fouling and enhance the flux through ultrafiltration membranes. A preliminary economic evaluation, accounting for the power consumption of the piezoelectric driver and the extent of permeate flow rate enhancement, has also shown that piezoelectrically assisted ultrafiltration is cost effective and economically competitive in comparison with traditional separation processes. Piezoelectric transducers, such as a piezoelectric lead zirconate titanate (PZT) disc or a piezoelectric horn, driven by moderate power, significantly enhance the permeate flux on fouled membranes, presumably because they promote local turbulence. Several experiments were conducted on polysulfone and regenerated cellulose UF membranes fouled during filtration of model feed solutions. Solutions of poly(ethylene glycol) and of high-molecular weight dextran were used as models. The authors found that they could significantly increase the permeate flux by periodically driving the piezoelectric transducer, horn or PZT disc, by application of moderate power over short periods of time, from 20 to 90 seconds. Enhancements as high as a factor of 8 were recorded within a few seconds, and enhanced permeate fluxes were maintained over a prolonged period (up to 3 hours). The prolonged flux enhancement makes it feasible to drive the piezoelectric transducer intermittently, thereby reducing the power consumption of the piezoelectric driver. As piezoelectric drivers of sonically assisted ultrafiltration, PZT disc transducers are preferred over the piezoelectric horn because of their small size and ease of adaptability to ultrafiltration test cells. The horn transmits sonic energy to the UF membrane through a titanium element driven by a separate piezoelectric transducer, but a piezoelectric ceramic disc transmits energy directly to the UF membrane.

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

    SciTech Connect

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

    2013-04-08

    Melting and solidification of SAC 305 lead-free solder joints in a wafer-level chip-scale package were examined in situ with synchrotron x-ray diffraction. The chips with balls attached (but not assembled to a circuit board) were reflowed one to three times using a temperature and time history similar to an industrial reflow process. Diffraction patterns from the same joint were collected every 0.5 s during the melting and solidification process. The solidification of the Sn phase in the solder joint occurred between 0.5 s and 1 s. During melting, most of the Sn melted in about 0.5 s, but in some cases took 2-5 s for the Sn peak to completely disappear. In one instance, the Sn peak persisted for 30 s. The Ag{sub 3}Sn peaks dissolved in about 1-2 s, but the Cu{sub 6}Sn{sub 5} peaks from the interface were persistent and did not change throughout the melting and solidification process. Completely different Sn crystal orientations were always developed upon resolidification.

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

    NASA Technical Reports Server (NTRS)

    Sampson, Michael J.

    2008-01-01

    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.

  18. Thermodynamic Stability and Defect Chemistry of Bismuth-Based Lead-Free Double Perovskites.

    PubMed

    Xiao, Zewen; Meng, Weiwei; Wang, Jianbo; Yan, Yanfa

    2016-09-22

    Bismuth- or antimony-based lead-free double perovskites represented by Cs2 AgBiBr6 have recently been considered promising alternatives to the emerging lead-based perovskites for solar cell applications. These new perovskites belong to the Fm3‾ m space group and consist of two types of octahedra alternating in a rock-salt face-centered cubic structure. We show, by density functional theory calculations, that the stable chemical potential region for pure Cs2 AgBiBr6 is narrow. Ag vacancies are a shallow accepters and can easily form, leading to intrinsic p-type conductivity. Bi vacancies and AgBi antisites are deep acceptors and should be the dominant defects under the Br-rich growth conditions. Our results suggest that the growth of Cs2 AgBiBr6 under Br-poor/Bi-rich conditions is preferred for suppressing the formation of the deep defects, which is beneficial for maximizing the photovoltaic performance.

  19. Enhanced interfacial thermal transport in pnictogen tellurides metallized with a lead-free solder alloy

    SciTech Connect

    Devender,; Ramanath, Ganpati; Lofgreen, Kelly; Devasenathipathy, Shankar; Swan, Johanna; Mahajan, Ravi; Borca-Tasciuc, Theodorian

    2015-11-15

    Controlling thermal transport across metal–thermoelectric interfaces is essential for realizing high efficiency solid-state refrigeration and waste-heat harvesting power generation devices. Here, the authors report that pnictogen chalcogenides metallized with bilayers of Sn{sub 96.5}Ag{sub 3}Cu{sub 0.5} solder and Ni barrier exhibit tenfold higher interfacial thermal conductance Γ{sub c} than that obtained with In/Ni bilayer metallization. X-ray diffraction and x-ray spectroscopy indicate that reduced interdiffusion and diminution of interfacial SnTe formation due to Ni layer correlates with the higher Γ{sub c}. Finite element modeling of thermoelectric coolers metallized with Sn{sub 96.5}Ag{sub 3}Cu{sub 0.5}/Ni bilayers presages a temperature drop ΔT ∼ 22 K that is 40% higher than that obtained with In/Ni metallization. Our results underscore the importance of controlling chemical intermixing at solder–metal–thermoelectric interfaces to increase the effective figure of merit, and hence, the thermoelectric cooling efficiency. These findings should facilitate the design and development of lead-free metallization for pnictogen chalcogenide-based thermoelectrics.

  20. Comparative shear tests of some low temperature lead-free solder pastes

    NASA Astrophysics Data System (ADS)

    Branzei, Mihai; Plotog, Ioan; Varzaru, Gaudentiu; Cucu, Traian C.

    2016-12-01

    The range of electronic components and as a consequence, all parts of automotive electronic equipment operating temperatures in a vehicle is given by the location of that equipment, so the maximum temperature can vary between 358K and 478K1. The solder joints could be defined as passive parts of the interconnection structure of automotive electronic equipment, at a different level, from boards of electronic modules to systems. The manufacturing costs reduction necessity and the RoHS EU Directive3, 7 consequences generate the trend to create new Low-Temperature Lead-Free (LTLF) solder pastes family9. In the paper, the mechanical strength of solder joints and samples having the same transversal section as resistor 1206 case type made using the same LTLF alloys into Vapour Phase Soldering (VPS) process characterized by different cooling rates (slow and rapid) and two types of test PCBs pads finish, were benchmarked at room temperature. The presented work extends the theoretical studies and experiments upon heat transfer in VPSP in order to optimize the technology for soldering process (SP) of automotive electronic modules and could be extended for home and modern agriculture appliances industry. The shear forces (SF) values of the LTLF alloy samples having the same transversal section as resistor 1206 case type will be considered as references values of a database useful in the new solder alloy creation processes and their qualification for automotive electronics domain.

  1. Enhanced electrocaloric effect near polymorphic phase boundary in lead-free potassium sodium niobate ceramics

    NASA Astrophysics Data System (ADS)

    Wang, Xiangjian; Wu, Jiagang; Dkhil, Brahim; Xu, Baixiang; Wang, Xiaopeng; Dong, Guohua; Yang, Guang; Lou, Xiaojie

    2017-02-01

    The electrocaloric (EC) effect in lead-free (1-x)(K0.48Na0.52)(Nb0.95Sb0.05)O3-xBi0.5(Na0.82K0.18)0.5ZrO3 ceramics was investigated using an indirect thermodynamic method. Large EC temperature changes were obtained in the vicinity of a polymorphic phase boundary at 40 kV/cm, e.g., 0.32 K at 359 K for x = 0.03, 0.51 K at 350 K for x = 0.04, and 0.48 K at 300 K for x = 0.05, respectively. These values are larger than the previous results at inter-ferroelectric phase transition and, more interestingly, are found to be comparable to those usually explored at the Curie temperature. The operational temperature window is broad near the polymorphic phase boundary due to the diffuseness of the phase transition. The enhanced electrocaloric effect is attributed to the formation of nanodomains near the polymorphic phase boundary, which reduces domain wall energy and facilitates the polarization rotation. The construction of a polymorphic phase boundary and the arrangement of coexisting phases at the nanoscale may open a promising route to explore EC materials.

  2. Discovering lead-free perovskite solar materials with a split-anion approach.

    PubMed

    Sun, Yi-Yang; Shi, Jian; Lian, Jie; Gao, Weiwei; Agiorgousis, Michael L; Zhang, Peihong; Zhang, Shengbai

    2016-03-28

    Organic-inorganic hybrid perovskite solar materials, being low-cost and high-performance, are promising for large-scale deployment of the photovoltaic technology. A key challenge that remains to be addressed is the toxicity of these materials since the high-efficiency solar cells are made of lead-containing materials, in particular, CH3NH3PbI3. Here, based on first-principles calculation, we search for lead-free perovskite materials based on the split-anion approach, where we replace Pb with non-toxic elements while introducing dual anions (i.e., splitting the anion sites) that preserve the charge neutrality. We show that CH3NH3BiSeI2 and CH3NH3BiSI2 exhibit improved band gaps and optical absorption over CH3NH3PbI3. The split-anion approach could also be applied to pure inorganic perovskites, significantly enlarging the pool of candidate materials in the design of low-cost, high-performance and environmentally-friendly perovskite solar materials.

  3. Subterahertz dielectric relaxation in lead-free Ba(Zr,Ti)O3 relaxor ferroelectrics

    NASA Astrophysics Data System (ADS)

    Wang, D.; Bokov, A. A.; Ye, Z.-G.; Hlinka, J.; Bellaiche, L.

    2016-04-01

    Relaxors are complex materials with unusual properties that have been puzzling the scientific community since their discovery. The main characteristic of relaxors, that is, their dielectric relaxation, remains unclear and is still under debate. The difficulty to conduct measurements at frequencies ranging from ~=1 GHz to ~=1 THz and the challenge of developing models to capture their complex dynamical responses are among the reasons for such a situation. Here, we report first-principles-based molecular dynamic simulations of lead-free Ba(Zr0.5Ti0.5)O3, which allows us to obtain its subterahertz dynamics. This approach reproduces the striking characteristics of relaxors including the dielectric relaxation, the constant-loss behaviour, the diffuse maximum in the temperature dependence of susceptibility, the substantial widening of dielectric spectrum on cooling and the resulting Vogel-Fulcher law. The simulations further relate such features to the decomposed dielectric responses, each associated with its own polarization mechanism, therefore, enhancing the current understanding of relaxor behaviour.

  4. First-Principles Investigations of Lead-Free Formamidinium Based Hybrid Perovskites

    NASA Astrophysics Data System (ADS)

    Murat, Altynbek; Schwingenschlögl, Udo

    2015-03-01

    Hybrid organic-inorganic perovskite solar cells have recently emerged as the next-generation photovoltaic technology. Most of the research work has been focused on the prototype MAPbI3 perovskite (MA = Methylammonium = CH3NH3+) and its analogues that have lead to power conversion efficiencies in excess of 15%. Despite the huge success, these materials are still non-optimal in terms of optical absorption where the bandgaps are greater than 1.6 eV as well as the toxicology issue of lead. Thus, investigation and development of lead-free perovskites with bandgaps closer to optimal, allowing greater spectral absorption, is of great interest. In this work, we perform first principles calculations to study the structural, optical, and electronic properties of new derivatives of MAPbI3 in which the organic MA cation is replaced by other organic amines of similar size such as Formamidinium (FA) and/or the Pb cation replaced by similar elements such as Sn. In particular, we investigate the role and effect of FA and Pb cations on the electronic and optical properties and analyze to which extend the bandgaps can be tuned.

  5. Tin pest in Sn-0.5 wt.% Cu lead-free solder

    NASA Astrophysics Data System (ADS)

    Kariya, Yoshiharu; Williams, Naomi; Gagg, Colin; Plumbridge, William

    2001-06-01

    Tin pest (the product of the allotropic transformation of β-tin into α-tin at temperatures below 286 K) has been observed in a Sn-0.5 wt.% Cu solder alloy. Some 40 percent of the specimen surface was transformed into gray tin after aging at 255K for 1.5 years, and after 1.8 years, the proportion increased to about 70 percent. The degree of transformation in work-hardened areas is much higher than in other areas, suggesting residual stress might provide an additional driving force for the transformation into α-tin. The allotropic change results in a 26 percent increase in volume, and cracks are initiated to accommodate the changes in volume. Results indicate that tin pest could lead to total disintegration of micro-electronic solder joints. The tin-copper eutectic system may become a prominent lead-free solder, and tin pest could have major ramifications on service lifetime of electronic assemblies.

  6. Characterization of Low-Melting-Point Sn-Bi-In Lead-Free Solders

    NASA Astrophysics Data System (ADS)

    Li, Qin; Ma, Ninshu; Lei, YongPing; Lin, Jian; Fu, HanGuang; Gu, Jian

    2016-11-01

    Development of lead-free solders with low melting temperature is important for substitution of Pb-based solders to reduce direct risks to human health and the environment. In the present work, Sn-Bi-In solders were studied for different ratios of Bi and Sn to obtain solders with low melting temperature. The microstructure, thermal properties, wettability, mechanical properties, and reliability of joints with Cu have been investigated. The results show that the microstructures of the Sn-Bi-In solders were composed of β-Sn, Bi, and InBi phases. The intermetallic compound (IMC) layer was mainly composed of Cu6Sn5, and its thickness increased slightly as the Bi content was increased. The melting temperature of the solders was around 100°C to 104°C. However, when the Sn content exceeded 50 wt.%, the melting range became larger and the wettability became worse. The tensile strength of the solder alloys and solder joints declined with increasing Bi content. Two fracture modes (IMC layer fracture and solder/IMC mixed fracture) were found in solder joints. The fracture mechanism of solder joints was brittle fracture. In addition, cleavage steps on the fracture surface and coarse grains in the fracture structure were comparatively apparent for higher Bi content, resulting in decreased elongation for both solder alloys and solder joints.

  7. A piezoelectric transformer

    NASA Technical Reports Server (NTRS)

    Won, C. C.

    1993-01-01

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

  8. Piezoelectric Templates - New Views on Biomineralization and Biomimetics.

    PubMed

    Stitz, Nina; Eiben, Sabine; Atanasova, Petia; Domingo, Neus; Leineweber, Andreas; Burghard, Zaklina; Bill, Joachim

    2016-05-23

    Biomineralization in general is based on electrostatic interactions and molecular recognition of organic and inorganic phases. These principles of biomineralization have also been utilized and transferred to bio-inspired synthesis of functional materials during the past decades. Proteins involved in both, biomineralization and bio-inspired processes, are often piezoelectric due to their dipolar character hinting to the impact of a template's piezoelectricity on mineralization processes. However, the piezoelectric contribution on the mineralization process and especially the interaction of organic and inorganic phases is hardly considered so far. We herein report the successful use of the intrinsic piezoelectric properties of tobacco mosaic virus (TMV) to synthesize piezoelectric ZnO. Such films show a two-fold increase of the piezoelectric coefficient up to 7.2 pm V(-1) compared to films synthesized on non-piezoelectric templates. By utilizing the intrinsic piezoelectricity of a biotemplate, we thus established a novel synthesis pathway towards functional materials, which sheds light on the whole field of biomimetics. The obtained results are of even broader and general interest since they are providing a new, more comprehensive insight into the mechanisms involved into biomineralization in living nature.

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

    NASA Astrophysics Data System (ADS)

    Demir, Mustafa; Aksöz, Sezen; Öztürk, Esra; Maraşlı, Necmettin

    2014-10-01

    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.

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

    SciTech Connect

    Rohatgi, P.K.

    1996-02-01

    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.

  11. Lead-Free MA2CuCl(x)Br(4-x) Hybrid Perovskites.

    PubMed

    Cortecchia, Daniele; Dewi, Herlina Arianita; Yin, Jun; Bruno, Annalisa; Chen, Shi; Baikie, Tom; Boix, Pablo P; Grätzel, Michael; Mhaisalkar, Subodh; Soci, Cesare; Mathews, Nripan

    2016-02-01

    Despite their extremely good performance in solar cells with efficiencies approaching 20% and the emerging application for light-emitting devices, organic-inorganic lead halide perovskites suffer from high content of toxic, polluting, and bioaccumulative Pb, which may eventually hamper their commercialization. Here, we present the synthesis of two-dimensional (2D) Cu-based hybrid perovskites and study their optoelectronic properties to investigate their potential application in solar cells and light-emitting devices, providing a new environmental-friendly alternative to Pb. The series (CH3NH3)2CuCl(x)Br(4-x) was studied in detail, with the role of Cl found to be essential for stabilization. By exploiting the additional Cu d-d transitions and appropriately tuning the Br/Cl ratio, which affects ligand-to-metal charge transfer transitions, the optical absorption in this series of compounds can be extended to the near-infrared for optimal spectral overlap with the solar irradiance. In situ formation of Cu(+) ions was found to be responsible for the green photoluminescence of this material set. Processing conditions for integrating Cu-based perovskites into photovoltaic device architectures, as well as the factors currently limiting photovoltaic performance, are discussed: among them, we identified the combination of low absorption coefficient and heavy mass of the holes as main limitations for the solar cell efficiency. To the best of our knowledge, this is the first demonstration of the potential of 2D copper perovskite as light harvesters and lays the foundation for further development of perovskite based on transition metals as alternative lead-free materials. Appropriate molecular design will be necessary to improve the material's properties and solar cell performance filling the gap with the state-of-the-art Pb-based perovskite devices.

  12. Concentration dependent luminescence properties of Dy3+ doped lead free zinc phosphate glasses for visible applications

    NASA Astrophysics Data System (ADS)

    Reddy Prasad, V.; Babu, S.; Ratnakaram, Y. C.

    2016-10-01

    Dysprosium (Dy3+) doped lead free zinc phosphate glasses with chemical compositions (60 - x) NH4H2PO4 + 20ZnO + 10BaF2 + 10NaF + xDy2O3 (where x = 0.5, 1.0, 1.5, 2.0 mol%) have been prepared by melt quenching technique. The functional groups of vibrational bands have been assigned and clearly elucidated by FTIR and Raman spectral profiles for all these glass samples. Judd-Ofelt (J-O) intensity parameters (Ωλ: λ = 2, 4, 6) have been obtained from spectral intensities of different absorption bands of Dy3+ doped glasses. Radiative properties such as radiative transition probabilities ( A R ), radiative lifetimes ( τ R ), branching ratios ( β R ) and integrated absorption cross-sections ( Σ) for different excited states are calculated by using J-O parameters. Luminescence spectra exhibit three emission bands (from 4F9/2 level to 6H15/2, 6H13/2 and 6H11/2) for all the concentrations of Dy3+ ions before and after gamma irradiation. Various luminescence properties have been studied by varying the Dy3+ concentration for the three spectral profiles. Fluorescence decay curves of 4F9/2 level have been recorded. The energy transfer mechanism that leads to quenching of 4F9/2 state lifetime has been discussed by the variation of Dy3+ concentration. These glasses are expected to be useful for yellow luminescent materials.

  13. Giant strain in lead-free piezoceramics Bi0.5Na0.5TiO3-BaTiO3-K0.5Na0.5NbO3 system

    NASA Astrophysics Data System (ADS)

    Zhang, Shan-Tao; Kounga, Alain Brice; Aulbach, Emil; Ehrenberg, Helmut; Rödel, Jürgen

    2007-09-01

    Piezoelectric actuators convert electrical into mechanical energy and are implemented for many large-scale applications such as piezoinjectors and ink jet printers. The performance of these devices is governed by the electric-field-induced strain. Here, the authors describe the development of a class of lead-free (0.94-x)Bi0.5Na0.5TiO3-0.06BaTiO3-xK0.5Na0.5NbO3 ceramics. These can deliver a giant strain (0.45%) under both unipolar and bipolar field loadings, which is even higher than the strain obtained with established ferroelectric Pb(Zr ,Ti)O3 ceramics and is comparable to strains obtained in Pb-based antiferroelectrics.

  14. Shielding properties of lead-free protective clothing and their impact on radiation doses.

    PubMed

    Schlattl, Helmut; Zankl, Maria; Eder, Heinrich; Hoeschen, Christoph

    2007-11-01

    The shielding properties of two different lead-free materials-tin and a compound of 80% tin and 20% bismuth-for protective clothing are compared with those of lead for three typical x-ray spectra generated at tube voltages of 60, 75, and 120 kV. Three different quantities were used to compare the shielding capability of the different materials: (1) Air-kerma attenuation factors in narrow-beam geometry, (2) air-kerma attenuation factors in broad-beam geometry, and (3) ratios of organ and effective doses in the human body for a whole-body irradiation with a parallel beam directed frontally at the body. The thicknesses of tin (0.45 mm) and the tin/bismuth compound (0.41 mm) to be compared against lead correspond to a lead equivalence value of 0.35 mm for the 75 kV spectrum. The narrow-beam attenuation factors for 0.45 mm tin are 54% and 32% lower than those for 0.35 mm lead for 60 and 120 kV; those for 0.41 mm tin/bismuth are 12% and 32% lower, respectively. The decrease of the broad-beam air-kerma attenuation factors compared to lead is 74%, 46%, and 41% for tin and 42%, 26%, and 33% for tin/bismuth and the spectra at 60, 75, and 120 kV, respectively. Therefore, it is recommended that the characterization of the shielding potential of a material should be done by measurements in broad-beam geometry. Since the secondary radiation that is mainly responsible for the shielding reduction in broad-beam geometry is of low penetrability, only more superficially located organs receive significantly enhanced doses. The increase for the dose to the glandular breast tissue (female) compared to being shielded by lead is 143%, 37%, and 45% when shielded by tin, and 35%, 15%, and 39% when shielded by tin/bismuth for 60, 75, and 120 kV, respectively. The effective dose rises by 60%, 6%, and 38% for tin, and 14%, 3% and, 35% for tin/bismuth shielding, respectively.

  15. Intermetallics Characterization of Lead-Free Solder Joints under Isothermal Aging

    NASA Astrophysics Data System (ADS)

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

    2008-08-01

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

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

    SciTech Connect

    Syh, J

    2014-06-01

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

  17. New (1 - x)K0.45Na0.55Nb0.96Sb0.04O3-xBi0.5Na0.5HfO3 lead-free ceramics: Phase boundary and their electrical properties

    NASA Astrophysics Data System (ADS)

    Tao, Hong; Wu, Jiagang; Zheng, Ting; Wang, Xiangjian; Lou, Xiaojie

    2015-07-01

    Here, we reported a high unipolar strain and large piezoelectricity in new (1 - x)K0.45Na0.55Nb0.96Sb0.04O3-xBi0.5Na0.5HfO3 ceramics. The rhombohedral-tetragonal (R-T) phase boundary was constructed in the ceramics with 0.03 < x ≤ 0.05, which shows a large d33 value of ˜419 pC/N. More importantly, a high unipolar strain of ˜0.31% was observed due to the multiphase coexistence. In addition, the piezoelectricity of the ceramics could be effectively enhanced if their compositions are located at the phase boundaries region, where a very low electric field of ˜1.2 kV/mm can readily rotate the R/T domains. We also noticed that the deviation from phase boundary induced by applying an external electric field results in the deterioration of piezoelectricity after the "second-poling" method. We believe that as a potassium-sodium-niobate based material, the ceramics developed in this work may find practical applications in lead-free piezoelectric devices such as actuators and fuel injectors in the future owing to the significant enhancement in their piezoelectricity as well as strain.

  18. Roles of service parameters on the mechanical behavior of lead-free solder joints

    NASA Astrophysics Data System (ADS)

    Rhee, Hongjoo

    2005-07-01

    Lead-based solders have been extensively used as interconnects in various electronic applications due to their low cost and suitable material properties. However, in view of environmental and health concerns, the electronics industry is forced to develop lead-free alternative solders. Eutectic Sn-3.5Ag based solders are being considered as suitable substitutes due to their non-toxicity, tolerable melting temperatures, and comparable mechanical as well as electrical properties. Smaller electronic packaging and emerging new technologies impose several constraints on the solder interconnect that require better inherent properties in the solder to resist failure during operation. Hence, it is important to develop a clear understanding of the deformation behavior of eutectic Sn-Ag solder joints. Mechanical characterization was performed to investigate the behavior of eutectic Sn-Ag solder joints. Peak shear stress and flow stress decreased with increasing testing temperature and with decreasing simple shear-strain rate. The effect of simple shear-strain rate on the peak shear stress was found to be more significant at temperature regimes less than 125°C. The deformation structure of specimens deformed at higher temperatures was dominated by grain boundary deformation, while at lower temperatures it was dominated by shear banding. Stress relaxation studies on eutectic Sn-Ag solder joints were carried out to provide a better understanding of various parameters contributing to thermomechanical damage accumulation. Monotonic stress relaxation tests at various pre-strain conditions and testing temperatures can provide information relevant to the effects of ramp rates during heating and cooling excursions experienced during thermomechanical fatigue. Peak shear stress and residual shear stress, resulting from stress relaxation period, decreased with increasing testing temperature for a given pre-strain condition. A faster ramp rate was found to cause higher resultant residual

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

    NASA Technical Reports Server (NTRS)

    Kessel, Kurt

    2011-01-01

    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

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

    NASA Astrophysics Data System (ADS)

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

    2012-07-01

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

  1. Piezoelectric cantilever sensors

    NASA Technical Reports Server (NTRS)

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

    2008-01-01

    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.

  2. Enhancement on wettability and intermetallic compound formation with an addition of Al on Sn-0.7Cu lead-free solder fabricated via powder metallurgy method

    NASA Astrophysics Data System (ADS)

    Adli, Nisrin; Razak, Nurul Razliana Abdul; Saud, Norainiza

    2016-07-01

    Due to the toxicity of lead (Pb), the exploration of another possibility for lead-free solder is necessary. Nowadays, SnCu alloys are being established as one of the lead-free solder alternatives. In this study, Sn-0.7Cu lead-free solder with an addition of 1wt% and 5wt% Al were investigated by using powder metallurgy method. The effect of Al addition on the wettability and intermetallic compound thickness (IMC) of Sn-0.7Cu-Al lead-free solder were appraised. Results showed that Al having a high potential to enhance Sn-0.7Cu lead-free solder due to its good wetting and reduction of IMC thickness. The contact angle and IMC of the Sn-0.7Cu-Al lead-free solder were decreased by 14.32% and 40% as the Al content increased from 1 wt% to 5 wt%.

  3. Adaptive piezoelectric sensoriactuator

    NASA Technical Reports Server (NTRS)

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

    1996-01-01

    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.

  4. Notes on Piezoelectricity

    SciTech Connect

    Redondo, Antonio

    2016-02-03

    These notes provide a pedagogical discussion of the physics of piezoelectricity. The exposition starts with a brief analysis of the classical (continuum) theory of piezoelectric phenomena in solids. The main subject of the notes is, however, a quantum mechanical analysis. We first derive the Frohlich Hamiltonian as part of the description of the electron-phonon interaction. The results of this analysis are then employed to derive the equations of piezoelectricity. A couple of examples with the zinc blende and and wurtzite structures are presented at the end

  5. Terminal Performance of Lead Free Pistol Bullets in Ballistic Gelatin Using Retarding Force Analysis from High Speed Video

    DTIC Science & Technology

    2016-04-04

    Comparative Analysis of Airborne Chemical Exposure to Air Force Small Arms Range In- structors, Air Force Institute of Technology, AFIT/GES...Terminal Performance of Lead-Free Pistol Bullets in Ballistic Gelatin Using Retarding Force Analysis from High Speed Video ELIJAH COURTNEY, AMY...for comparison with earlier analysis of jacketed lead bullets. Peak retard- ing force and energy deposit in calibrated ballistic gelatin are

  6. Piezoelectric micromotors for microrobots

    NASA Astrophysics Data System (ADS)

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

    1992-03-01

    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 lens placed upon the stator becomes the spinning rotor. Piezoelectric micromotors overcome the problems currently associated with electrostatic micromotors such as low torque, friction, and the need for high voltage excitation. More importantly, they may offer a much simpler mechanism for coupling power out. Using thin films of lead zirconate titanate on silicon nitride membranes, various types of actuator structures can be fabricated. By combining new robot control systems with piezoelectric motors and micromechanics, the authors propose creating micromechanical systems that are small, cheap and completely autonomous.

  7. Energy collection via Piezoelectricity

    NASA Astrophysics Data System (ADS)

    Naveen Kumar, Ch

    2015-12-01

    In the present days, wireless data transmission techniques are commonly used in electronic devices. For powering them connection needs to be made to the power supply through wires else power may be supplied from batteries. Batteries require charging, replacement and other maintenance efforts. So, some alternative methods need to be developed to keep the batteries full time charged and to avoid the need of any consumable external energy source to charge the batteries. Mechanical energy harvesting utilizes piezoelectric components where deformations produced by different means are directly converted to electrical charge via piezoelectric effect. The proposed work in this research recommends Piezoelectricity as a alternate energy source. The motive is to obtain a pollution-free energy source and to utilize and optimize the energy being wasted. Current work also illustrates the working principle of piezoelectric crystal and various sources of vibration for the crystal.

  8. Laminated piezoelectric transformer

    NASA Technical Reports Server (NTRS)

    Vazquez Carazo, Alfredo (Inventor)

    2006-01-01

    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.

  9. Piezoelectric Energy Harvesting Solutions

    PubMed Central

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

    2014-01-01

    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

  10. Piezoelectrically Enhanced Photocathodes

    NASA Technical Reports Server (NTRS)

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

    2011-01-01

    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

  11. Stretchable piezoelectric nanocomposite generator.

    PubMed

    Park, Kwi-Il; Jeong, Chang Kyu; Kim, Na Kyung; Lee, Keon Jae

    2016-01-01

    Piezoelectric energy conversion that generate electric energy from ambient mechanical and vibrational movements is promising energy harvesting technology because it can use more accessible energy resources than other renewable natural energy. In particular, flexible and stretchable piezoelectric energy harvesters which can harvest the tiny biomechanical motions inside human body into electricity properly facilitate not only the self-powered energy system for flexible and wearable electronics but also sensitive piezoelectric sensors for motion detectors and in vivo diagnosis kits. Since the piezoelectric ZnO nanowires (NWs)-based energy harvesters (nanogenerators) were proposed in 2006, many researchers have attempted the nanogenerator by using the various fabrication process such as nanowire growth, electrospinning, and transfer techniques with piezoelectric materials including polyvinylidene fluoride (PVDF) polymer and perovskite ceramics. In 2012, the composite-based nanogenerators were developed using simple, low-cost, and scalable methods to overcome the significant issues with previously-reported energy harvester, such as insufficient output performance and size limitation. This review paper provides a brief overview of flexible and stretchable piezoelectric nanocomposite generator for realizing the self-powered energy system with development history, power performance, and applications.

  12. Stretchable piezoelectric nanocomposite generator

    NASA Astrophysics Data System (ADS)

    Park, Kwi-Il; Jeong, Chang Kyu; Kim, Na Kyung; Lee, Keon Jae

    2016-06-01

    Piezoelectric energy conversion that generate electric energy from ambient mechanical and vibrational movements is promising energy harvesting technology because it can use more accessible energy resources than other renewable natural energy. In particular, flexible and stretchable piezoelectric energy harvesters which can harvest the tiny biomechanical motions inside human body into electricity properly facilitate not only the self-powered energy system for flexible and wearable electronics but also sensitive piezoelectric sensors for motion detectors and in vivo diagnosis kits. Since the piezoelectric ZnO nanowires (NWs)-based energy harvesters (nanogenerators) were proposed in 2006, many researchers have attempted the nanogenerator by using the various fabrication process such as nanowire growth, electrospinning, and transfer techniques with piezoelectric materials including polyvinylidene fluoride (PVDF) polymer and perovskite ceramics. In 2012, the composite-based nanogenerators were developed using simple, low-cost, and scalable methods to overcome the significant issues with previously-reported energy harvester, such as insufficient output performance and size limitation. This review paper provides a brief overview of flexible and stretchable piezoelectric nanocomposite generator for realizing the self-powered energy system with development history, power performance, and applications.

  13. Effect of Ag-content on structure, corrosion behaviour and mechanical properties of Sn-9Zn lead-free solder alloy

    NASA Astrophysics Data System (ADS)

    Said Gouda, El; Abdel Aziz, H.; El Gendy, Y.; Saad Allah, F.; Hammam, M.

    2010-12-01

    The effect of (0.5-3.5) wt.% Ag additions on microstructure, melting, corrosion and mechanical properties of Sn-9Zn eutectic lead-free solder alloy has been studied and analyzed. The study included X-ray diffraction and scanning electron microscopy (SEM) to identify the microstructure of these alloys. The results showed that, continuous additions of Ag caused formation of Ag-Zn and Ag-Sn compounds which led to decrease the precipitations of Zn in Sn-matrix. These compounds led to increase the melting point of the alloys, which confirmed by the formation of small endothermic peaks in the higher temperature range followed the main peak of the DTA curves. Also, the DTA measurements confirmed that the alloy of composition Sn-9Zn-3.5Ag is the ternary eutectic alloy. Vicker's micro-hardness number of Sn-9Zn alloy increases with small additions of 0.5 and 1 wt.% Ag. Furthermore, it decreases to lower values with further increase of Ag content. Also, micro-creep behaviour, creep rate and corrosion behaviour of the Sn-9Zn-Ag alloys have been measured at room temperature.

  14. Piezoelectric Ceramics and Their Applications

    ERIC Educational Resources Information Center

    Flinn, I.

    1975-01-01

    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)

  15. High Temperature Piezoelectric Drill

    NASA Technical Reports Server (NTRS)

    Bao, Xiaoqi; Scott, James; Boudreau, Kate; Bar-Cohen, Yoseph; Sherrit, Stewart; Badescu, Mircea; Shrout, Tom; Zhang, Shujun

    2009-01-01

    The current NASA Decadal mission planning effort has identified Venus as a significant scientific target for a surface in-situ sampling/analyzing mission. The Venus environment represents several extremes including high temperature (460 deg C), high pressure (9 MPa), and potentially corrosive (condensed sulfuric acid droplets that adhere to surfaces during entry) environments. This technology challenge requires new rock sampling tools for these extreme conditions. Piezoelectric materials can potentially operate over a wide temperature range. Single crystals, like LiNbO3, have a Curie temperature that is higher than 1000 deg C and the piezoelectric ceramics Bismuth Titanate higher than 600 deg C. A study of the feasibility of producing piezoelectric drills that can operate in the temperature range up to 500 deg C was conducted. The study includes the high temperature properties investigations of engineering materials and piezoelectric ceramics with different formulas and doping. The drilling performances of a prototype Ultrasonic/Sonic Drill/Corer (USDC) using high temperate piezoelectric ceramics and single crystal were tested at temperature up to 500 deg C. The detailed results of our study and a discussion of the future work on performance improvements are presented in this paper.

  16. Active Piezoelectric Diaphragms

    NASA Technical Reports Server (NTRS)

    Bryant, Robert G.; Effinger, Robert T., IV; Aranda, Isaiah, Jr.; Copeland, Ben M.; Covington, Ed W., III

    2002-01-01

    Several active piezoelectric diaphragms were fabricated by placing unelectroded piezoelectric disks between copper clad films patterned with Inter-Circulating Electrodes "ICE". When a voltage potential is applied to the electrodes, the result is radially distributed electric field that mechanically strains the piezo-ceramic along the Z-axis (perpendicular to the applied electric field), rather than the expected in-plane (XY-axis) direction. Unlike other out of plane piezoelectric actuators, which are benders, these Radial Field Diaphragms (RFDs) strain concentrically yet afford high displacements while maintaining a constant circumference. This paper covers the fabrication and characterization of these diaphragms as a function of poling field strength, ceramic diameter and line spacing, as well as the surface topography, the resulting strain field and displacement as a function of applied voltage ranging from DC to 10 Hz.

  17. Piezoelectric Motors and Transformers

    NASA Astrophysics Data System (ADS)

    Uchino, K.

    Piezoelectric ceramics forms a new field between electronic and structural ceramics [1-4]. Application fields are classified into three categories: positioners, motors, and vibration suppressors. From the market research result for 80 Japanese component industries in 1992, tiny motors in the range of 5-8 mm are required in large numbers for office and portable equipment; the conventional electromagnetic (EM) motors are rather difficult to produce in this size with sufficient energy efficiency, while Silicon MEMS actuators are too small to be used in practice. Piezoelectric ultrasonic motors whose efficiency is insensitive to size are superior in the millimeter motor area. The manufacturing precision of optical instruments such as lasers and cameras, and the positioning accuracy for fabricating semiconductor chips are of the order of 0.1μm which is much smaller than the backlash of the EM motors. Vibration suppression in space structures and military vehicles also require compact but mighty piezoelectric actuators.

  18. Piezoelectric micromotors for microrobots

    NASA Astrophysics Data System (ADS)

    Flynn, Anita M.; Tavrow, Lee S.; Bart, Stephen F.; Brooks, Rodney A.

    1991-02-01

    Mobile robots are able to carry more and more intelligence (and in smaller packages) onboard everyday. Now we would like to match the brawn of our robots to the same scale as the brain. Towards this end, we have fabricated some small, a few millimeters in diameter, piezoelectric motors using ferroelectric thin films. These motors consist of two pieces: a stator and a rotor. The stationary stator includes a piezoelectric film in which we induce bending in the form of a traveling wave. Anything which sits atop the stator is propelled by the wave. A small glass lens placed upon the stator becomes the spinning rotor. Piezoelectric micromotors overcome the problems currently associated with electrostatic micromotors such as low torque, friction, and the need for high voltage excitation.

  19. Piezoelectric wave motor

    DOEpatents

    Yerganian, Simon Scott

    2003-02-11

    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.

  20. Piezoelectric wave motor

    DOEpatents

    Yerganian, Simon Scott

    2001-07-17

    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.

  1. Magnetoelectric studies on CoFe2O4/0.5(BaTi0.8Zr0.2O3)-0.5(Ba0.7Ca0.3TiO3) lead-free bilayer thin films derived by the chemical solution deposition

    NASA Astrophysics Data System (ADS)

    Venkata Ramana, E.; Zavašnik, Janez; Graça, M. P. F.; Valente, M. A.

    2016-08-01

    Lead-free multiferroic bilayer thin films were fabricated on (111)Pt/Si substrate via a simple sol-gel chemical solution deposition, by altering the position of piezoelectric (Ba0.85Ca0.15) (Ti0.9Zr0.1)O3 (BCTZO) and ferromagnetic CoFe2O4 (CFO). Single layer BCTZO experiences the out-of-plane compressive stress, while this layer is under tensile strain in both the bilayers. The microstructural study confirms the formation of bilayers with expected chemical composition composed of multiple well-developed crystallites having no crystallographic dependencies. Thin films of BCTZO and CFO/BCTZO exhibited saturated ferroelectric hysteresis loops at room temperature with a Pr of 7.2 and 5.6 μC/cm2. The magnetic field induced shift in phonon vibrations coupled with direct magnetoelectric (ME) measurements demonstrated a stress-mediated coupling mechanism in the bilayers. We found a superior ME coefficient (105 MV/cm Oe) and dielectric tunability (˜52%) for CFO/BCTZO bilayer compared to the BCTZO/CFO bilayer, which demonstrates that the modification of strain state in bilayers is useful for the desired ME coupling. The BCTZO having piezoelectricity on par with that of lead-based ones can be useful to tailor lead-free ME applications.

  2. Composition- and temperature-driven phase transition characteristics and associated electromechanical properties in Bi0.5Na0.5TiO3-based lead-free ceramics.

    PubMed

    Bai, Wangfeng; Chen, Daqin; Zheng, Peng; Shen, Bo; Zhai, Jiwei; Ji, Zhenguo

    2016-05-17

    In this study, a lead-free ceramic system comprising (0.94 - x)Bi0.5Na0.5TiO3-0.06BaTiO3-xBi(Zn0.5Ti0.5)O3 (BNT-BT-BZT) was designed and prepared by a conventional solid-state reaction method. The effect of the addition of BZT on the phase transition characteristics and associated electromechanical properties of BNT-BT was systematically discussed and a schematic phase diagram was established. The addition of BZT had a strong impact on the phase transition as well as the strain and piezoelectric activity. The phase coexistence, which involves ferroelectric rhombohedral-relaxor pseudocubic phases, can be driven by modification with BZT and increases in temperature and can be confirmed by XRD measurements, analysis of Raman spectra and temperature-dependent changes in polarization and strain hysteresis loops. Accompanied by a shift in the ferroelectric-to-relaxor temperature TF-R to below room temperature on the addition of BZT, a compositionally induced ferroelectric-to-relaxor phase transition occurred, which gave rise to a large strain of 0.33% with a normalized strain Smax/Emax of 550 pm V(-1) at the critical BZT content x of 0.0275. The results were closely correlated with the composition and dependence on temperature of the phase transition, which significantly influenced the electromechanical properties, and the origin of the large strain observed in the present system was also addressed in detail. As a result, the design principles provided in this study open the possibility of obtaining BNT-based lead-free ceramics with enhanced electromechanical properties for actuator applications.

  3. Evaluation of Lead Release in a Simulated Lead-Free Premise Plumbing System Using a Sequential Sampling Approach.

    PubMed

    Ng, Ding-Quan; Lin, Yi-Pin

    2016-02-27

    In this pilot study, a modified sampling protocol was evaluated for the detection of lead contamination and locating the source of lead release in a simulated premise plumbing system with one-, three- and seven-day stagnation for a total period of 475 days. Copper pipes, stainless steel taps and brass fittings were used to assemble the "lead-free" system. Sequential sampling using 100 mL was used to detect lead contamination while that using 50 mL was used to locate the lead source. Elevated lead levels, far exceeding the World Health Organization (WHO) guideline value of 10 µg · L(-1), persisted for as long as five months in the system. "Lead-free" brass fittings were identified as the source of lead contamination. Physical disturbances, such as renovation works, could cause short-term spikes in lead release. Orthophosphate was able to suppress total lead levels below 10 µg · L(-1), but caused "blue water" problems. When orthophosphate addition was ceased, total lead levels began to spike within one week, implying that a continuous supply of orthophosphate was required to control total lead levels. Occasional total lead spikes were observed in one-day stagnation samples throughout the course of the experiments.

  4. Direct and indirect characterization of electrocaloric effect in (Na,K)NbO3 based lead-free ceramics

    NASA Astrophysics Data System (ADS)

    Li, Jianting; Bai, Yang; Qin, Shiqiang; Fu, Jian; Zuo, Ruzhong; Qiao, Lijie

    2016-10-01

    This paper demonstrated the electrocaloric effect (ECE) of (Na0.52K0.48-x)(Nb0.92-xSb0.08)O3-xLiTaO3 lead-free ceramics by direct differential scanning calorimetry measurement and indirect thermodynamic method. Both results show good consistency, where the direct one more accurately depicts ECE value and its evolution according to phase diagram. Due to the diffuse orthorhombic-tetragonal phase transition, the samples show a broad ECE peak which shifts to lower temperature with increasing LiTaO3 amount. Compared to previous direct results in lead-free ceramics at corresponding temperatures, they show a competitive ECE performance with ΔTmax of 0.41 K (@80 °C), 0.30 K (@35 °C) and 0.16 K (@15 °C) under 20 kV/cm fields for x = 0.02, 0.0375 and 0.045.

  5. Piezoelectric allostery of protein

    NASA Astrophysics Data System (ADS)

    Ohnuki, Jun; Sato, Takato; Takano, Mitsunori

    2016-07-01

    Allostery is indispensable for a protein to work, where a locally applied stimulus is transmitted to a distant part of the molecule. While the allostery due to chemical stimuli such as ligand binding has long been studied, the growing interest in mechanobiology prompts the study of the mechanically stimulated allostery, the physical mechanism of which has not been established. By molecular dynamics simulation of a motor protein myosin, we found that a locally applied mechanical stimulus induces electrostatic potential change at distant regions, just like the piezoelectricity. This novel allosteric mechanism, "piezoelectric allostery", should be of particularly high value for mechanosensor/transducer proteins.

  6. Synthesis and characterization of lead-free tin silver nanosolders and their application to halogen free nanosolder pastes

    NASA Astrophysics Data System (ADS)

    Wernicki, Evan

    Solder paste is a key material used in attaching electronic components to printed circuit boards (PCBs). Commonly used lead-based solders, such as eutectic Sn/37Pb, are currently being replaced by lead-free alloy materials due to health and environmental concerns associated with lead. Many solder pastes, both lead-containing and lead-free, contain halogens which act as activators to remove surface oxide and enhance surface wetting, posing further environmental concern from the halogen species. Difficulties in obtaining reliable joints can occur since lead-free solder material candidates have higher melting temperatures (30-50 °C) than that of lead-based solders. Differences in material properties between the numerous materials used in assembly and packaging processes can lead to component damage during manufacturing. Furthermore, designs that include more electrical interconnects in smaller areas give rise for the need for new materials to allow this trend to continue. A surfactant-assisted chemical reduction method was used to synthesize Sn/Ag alloy nanoparticles with a target composition range of 3.5-5 wt% Ag that served as the lead-free solder material within a nanosolder paste. Structure and size characterization via SEM and TEM showed Sn-Ag nanosolders size average approximately 19 nm. Differential scanning calorimetry (DSC) measurements of the nanosolder samples containing 4.5 wt% Ag showed an endothermic peak at 222.5 °C and an onset of 219.2 °C, indicating up to 17.5 °C melting temperature depression when compared to the bulk liquidus value of 240 °C. Composition of the nanosolder material was confirmed using energy dispersive x-ray spectroscopy (EDS) and structures formed were analyzed via x-ray diffraction (XRD). Both halogen-free and halogen-containing flux materials were combined with the nanosolder material, respectively, with varying preparation parameters to form a design of experiments (DoE) for nanosolder paste preparation. Solder pastes

  7. Design of optimized piezoelectric HDD-sliders

    NASA Astrophysics Data System (ADS)

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

    2010-04-01

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

  8. Microstructural and Hardness Evaluations of a Centrifuged Sn-22Pb Casting Alloy Compared with a Lead-Free SnAg Alloy

    NASA Astrophysics Data System (ADS)

    Satizabal, Luz Myrian; Costa, Diego; Hainick, Guilherme Ottamr; Moura, Diego Rodrigo; Bortolozo, Ausdinir Danilo; Osório, Wislei Riuper

    2017-01-01

    A great preoccupation with replacing the traditional Sn-Pb alloy with a Pb-free alloy ("green alloy") is recognized. There are industrial sectors that demand metallurgical improvements to attain certain unsoundness and adequate properties as a function of imposed operational parameters. In this experimental investigation, two distinctive centrifuged casting alloys (i.e., Sn-2 wt pct Ag and Sn-22 wt pct Pb) are compared. It is found that centrifuged castings have similar microstructure constituents, although distinctive cooling rates and solute contents are considered. It is also found that Ag3Sn intermetallic particles are responsible for attaining similar tensile strength, since more dislocations between Ag3Sn particles and the Sn-rich phase are provided. In order to replace the Sn-Pb alloys with a successor alloy containing sustainability and environmental aspects associated with castability and to guarantee the desired properties, it seems that a green alloy (Pb free) with intermetallic particles finely and homogeneously distributed provides an interesting benefit to various industrial applications.

  9. Microstructural and Hardness Evaluations of a Centrifuged Sn-22Pb Casting Alloy Compared with a Lead-Free SnAg Alloy

    NASA Astrophysics Data System (ADS)

    Satizabal, Luz Myrian; Costa, Diego; Hainick, Guilherme Ottamr; Moura, Diego Rodrigo; Bortolozo, Ausdinir Danilo; Osório, Wislei Riuper

    2017-04-01

    A great preoccupation with replacing the traditional Sn-Pb alloy with a Pb-free alloy ("green alloy") is recognized. There are industrial sectors that demand metallurgical improvements to attain certain unsoundness and adequate properties as a function of imposed operational parameters. In this experimental investigation, two distinctive centrifuged casting alloys ( i.e., Sn-2 wt pct Ag and Sn-22 wt pct Pb) are compared. It is found that centrifuged castings have similar microstructure constituents, although distinctive cooling rates and solute contents are considered. It is also found that Ag3Sn intermetallic particles are responsible for attaining similar tensile strength, since more dislocations between Ag3Sn particles and the Sn-rich phase are provided. In order to replace the Sn-Pb alloys with a successor alloy containing sustainability and environmental aspects associated with castability and to guarantee the desired properties, it seems that a green alloy (Pb free) with intermetallic particles finely and homogeneously distributed provides an interesting benefit to various industrial applications.

  10. Conduction phenomenon of Al3+ modified lead free (Na0.5Bi0.5)0.92Ba0.08TiO3 electroceramics

    NASA Astrophysics Data System (ADS)

    Borkar, Hitesh; Kumar, Ashok

    2016-05-01

    Choice of proper dopants at A or B-site of ABO3 perovskite structure can modify the morphotropic phase boundary (MPB), and hence functional properties of polar systems. The chemical nature of donor or acceptor will significantly influence the fundamental properties. Lead-free ferroelectrics have vast potential to replace the lead-based ceramics. The (Na0.5Bi0.5)1-xBaxTiO3 (NBT-BT) (at x=0.08) near MPB with small substitution of trivalent cations (Al3+) has been synthesized by solid state reaction route. The aim to choose the trivalent cations (Al3+) was its relatively smaller radii than that of Bi3+ cations to develop the antipolar phases in the ferroelectric ceramic. Structural, morphological and elemental compositional analyses were studied by X-ray diffraction (XRD), Secondary electron microscope (SEM) and Energy-dispersive X-ray spectroscopy (EDAX), respectively. Ferroelectric studies were carried out on various compositions of (Na0.46Bi0.46-xAlxBa0.08)TiO3 (NBAT-BT) (x=0, 0.05, 0.07, 0.10) electroceramics. It was observed that with increase in concentration of Al the ferroelectricity state changes from soft to hard. Temperature dependent dielectric spectroscopy shows broad dielectric dispersion. The Al doping diminishes the relaxor behavior of NBT-BT ceramics. Impedance spectroscopy shows that electrical resistivity and relaxation frequency decreases with increase in Al-concentration. Modulus spectra indicate that Al significantly change the bulk capacitance of NBT-BT.

  11. UHV piezoelectric translator

    SciTech Connect

    Oversluizen, T.; Watson, G.

    1985-01-01

    A UHV compatible piezoelectric translator has been developed to correct for angular misalignments in the crysals of a UHV x-ray monochromator. The unit is small, bakeable to 150/sup 0/C, and uses only ceramic materials for insulation. We report on the construction details, vacuum compatibility, mechanical properties, and uses of the device.

  12. Piezoelectric actuator renaissance

    NASA Astrophysics Data System (ADS)

    Uchino, Kenji

    2015-03-01

    This paper resumes the content of the invited talk of the author, read at the occasion of the International Workshop on Relaxor Ferroelectrics, IWRF 14, held on October 12-16, 2014 in Stirin, Czech Republic. It reviews the recent advances in materials, designing concepts, and new applications of piezoelectric actuators, as well as the future perspectives of this area.

  13. Effects of metallic nanoparticle doped flux on the interfacial intermetallic compounds between lead-free solder ball and copper substrate

    SciTech Connect

    Sujan, G.K. Haseeb, A.S.M.A. Afifi, A.B.M.

    2014-11-15

    Lead free solders currently in use are prone to develop thick interfacial intermetallic compound layers with rough morphology which are detrimental to the long term solder joint reliability. A novel method has been developed to control the morphology and growth of intermetallic compound layers between lead-free Sn–3.0Ag–0.5Cu solder ball and copper substrate by doping a water soluble flux with metallic nanoparticles. Four types of metallic nanoparticles (nickel, cobalt, molybdenum and titanium) were used to investigate their effects on the wetting behavior and interfacial microstructural evaluations after reflow. Nanoparticles were dispersed manually with a water soluble flux and the resulting nanoparticle doped flux was placed on copper substrate. Lead-free Sn–3.0Ag–0.5Cu solder balls of diameter 0.45 mm were placed on top of the flux and were reflowed at a peak temperature of 240 °C for 45 s. Angle of contact, wetting area and interfacial microstructure were studied by optical microscopy, field emission scanning electron microscopy and energy-dispersive X-ray spectroscopy. It was observed that the angle of contact increased and wetting area decreased with the addition of cobalt, molybdenum and titanium nanoparticles to flux. On the other hand, wettability improved with the addition of nickel nanoparticles. Cross-sectional micrographs revealed that both nickel and cobalt nanoparticle doping transformed the morphology of Cu{sub 6}Sn{sub 5} from a typical scallop type to a planer one and reduced the intermetallic compound thickness under optimum condition. These effects were suggested to be related to in-situ interfacial alloying at the interface during reflow. The minimum amount of nanoparticles required to produce the planer morphology was found to be 0.1 wt.% for both nickel and cobalt. Molybdenum and titanium nanoparticles neither appear to undergo alloying during reflow nor have any influence at the solder/substrate interfacial reaction. Thus, doping

  14. Characterization of deformation in tin-silver lead-free solders during thermomechanical fatigue using orientation imaging microscopy

    NASA Astrophysics Data System (ADS)

    Telang, Adwait U.

    Eutectic Sn-Ag solder joints with copper substrate with different joint geometries were subjected to isothermal aging, creep at room and elevated temperature, and thermomechanical fatigue (TMF). Orientation Imaging Microscopy (OIM) studies reveal how the crystallographic orientations are correlated with microstructural features in the solder joints. Certain misorientations appear to be energetically favored during solidification, which have twin and Sigma boundary type relationships. Changes in the crystallographic orientations, grain size and misorientation angles between grains, occurring due to subsequent heating and/or deformation were documented and analyzed. This study shows that the lead-free solder joints are multi-crystals, so that deformation is very heterogeneous and sensitive to crystal orientation, strain and the temperature history. High temperature processes caused polygonization of dislocations into low angle grain boundaries that slid. Special boundaries also show sliding, which adds to the deformation. Mechanisms that cause grain boundary sliding and pop-up are presented and discussed.

  15. Reduced risk of acute poisoning in Australian cattle from used motor oils after introduction of lead-free petrol.

    PubMed

    Burren, B G; Reichmann, K G; McKenzie, R A

    2010-06-01

    Lead (Pb) poisoning of cattle has been relatively common in Australia and sump oil has been identified as an important cause of Pb toxicity for cattle because they seem to have a tendency to drink it. Lead-free petrol has been available in Australia since 1975, so the aim of this study was to assess the current risk to cattle from drinking used automotive oils. Sump or gear box oil was collected from 56 vehicles being serviced. The low levels of Pb found suggest that the removal of leaded petrol from the Australian market as a public health measure has benefited cattle by eliminating the risk of acute poisoning from used engine oil.

  16. Lead free KNN/P(VDF-TrFE) 0-3 pyroelectric composite films and its infrared sensor

    NASA Astrophysics Data System (ADS)

    Zhang, W. L.; Yu, Y. C.; Luo, W. B.; Shuai, Y.; Pan, X. Q.; Wu, Q. Q.; Wu, C. G.

    2017-01-01

    (K0.5Na0.5)NbO3 (KNN)/[P(VDF-TrFE)70:30] composite thick films with different KNN weight ratios have been fabricated and the effect of KNN mass content on the material structure and properties have been studied in this paper. Properties of the infrared sensor based KNN/[P(VDF-TrFE)70:30] composite thick film were also systematically studied. It was found that the sample containing 30 wt.% KNN show optimal properties for pyroelectric appliance and the highest pyroelectric coefficient was 63 μCm-2 K-1. Infrared sensors using 30 wt.% KNN-70 wt.%[P(VDF-TrFE)70:30] show highest detectivity (D∗ = 3.21 × 108 cm Hz1/2 W-1) at 137.3 Hz, indicating it is an promising candidate in lead-free quick response infrared detectors.

  17. Lead Free Electric Primer

    DTIC Science & Technology

    2011-10-06

    and 10-micron) and molybdenum trioxide (40 nm and 1.6 mm), using two different solvents (hexane and iso-propanol). The results are shown in Table 18...To date there has not been a single incident with the current aluminum/ molybdenum formulation. This demonstrates that the LFEP can be used with...15 Molybdenum Trioxide

  18. Lead-free solder

    DOEpatents

    Anderson, Iver E.; Terpstra, Robert L.

    2001-05-15

    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.

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

    SciTech Connect

    Chauhan, Aditya; Patel, Satyanarayan; Vaish, Rahul

    2014-08-15

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

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

    NASA Astrophysics Data System (ADS)

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

    2013-03-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2011-04-01

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

  2. Dielectric, thermal and Raman spectroscopy studies of lead-free (Na0.5Bi0.5)1-xSrxTiO3 (x = 0, 0.04 and 0.06) ceramics

    NASA Astrophysics Data System (ADS)

    Suchanicz, J.; Bovtun, V.; Dutkiewicz, E. M.; Konieczny, K.; Sitko, D.; Kluczewska, K.; Wajda, A.; Kalvane, A.; Sternberg, A.

    2016-08-01

    Lead-free (Na0.5Bi0.5)1-xSrxTiO3 (x = 0, 0.04 and 0.06) ceramics with relative densities above 97% were prepared by solid-state synthesis process. Their dielectric, thermal and Raman properties were studied. X-ray diffraction analysis shows perovskite structure with rhombohedral symmetry at room temperature. Sr doping of Na0.5Bi0.5TiO3 (NBT) results in an increase of the dielectric permittivity, diffusing of the permittivity maximum and its shift toward lower temperatures. The temperature of the rhombohedral-tetragonal phase transition indicated by the differential scanning calorimetry (DSC) peak and relaxational dielectric anomaly near the depolarization temperature are also shifted toward lower temperatures. The observed increase and broadening of the permittivity maximum, enhancement of the dielectric relaxation near the depolarization temperature, broadening of the DSC anomaly related to the rhombohedral-tetragonal phase transition and broadening of the Raman bands with increasing Sr content are attributed to the increase of the degree of cationic disorder and evident enhancement of the relaxor-like features in NBT-xST. This enhancement could play a positive role in the improvement of the piezoelectric performance of NBT-based ceramics.

  3. Lead-free epitaxial ferroelectric material integration on semiconducting (100) Nb-doped SrTiO3 for low-power non-volatile memory and efficient ultraviolet ray detection.

    PubMed

    Kundu, Souvik; Clavel, Michael; Biswas, Pranab; Chen, Bo; Song, Hyun-Cheol; Kumar, Prashant; Halder, Nripendra N; Hudait, Mantu K; Banerji, Pallab; Sanghadasa, Mohan; Priya, Shashank

    2015-07-23

    We report lead-free ferroelectric based resistive switching non-volatile memory (NVM) devices with epitaxial (1-x)BaTiO3-xBiFeO3 (x = 0.725) (BT-BFO) film integrated on semiconducting (100) Nb (0.7%) doped SrTiO3 (Nb:STO) substrates. The piezoelectric force microscopy (PFM) measurement at room temperature demonstrated ferroelectricity in the BT-BFO thin film. PFM results also reveal the repeatable polarization inversion by poling, manifesting its potential for read-write operation in NVM devices. The electroforming-free and ferroelectric polarization coupled electrical behaviour demonstrated excellent resistive switching with high retention time, cyclic endurance, and low set/reset voltages. X-ray photoelectron spectroscopy was utilized to determine the band alignment at the BT-BFO and Nb:STO heterojunction, and it exhibited staggered band alignment. This heterojunction is found to behave as an efficient ultraviolet photo-detector with low rise and fall time. The architecture also demonstrates half-wave rectification under low and high input signal frequencies, where the output distortion is minimal. The results provide avenue for an electrical switch that can regulate the pixels in low or high frequency images. Combined this work paves the pathway towards designing future generation low-power ferroelectric based microelectronic devices by merging both electrical and photovoltaic properties of BT-BFO materials.

  4. Lead-free epitaxial ferroelectric material integration on semiconducting (100) Nb-doped SrTiO3 for low-power non-volatile memory and efficient ultraviolet ray detection

    NASA Astrophysics Data System (ADS)

    Kundu, Souvik; Clavel, Michael; Biswas, Pranab; Chen, Bo; Song, Hyun-Cheol; Kumar, Prashant; Halder, Nripendra N.; Hudait, Mantu K.; Banerji, Pallab; Sanghadasa, Mohan; Priya, Shashank

    2015-07-01

    We report lead-free ferroelectric based resistive switching non-volatile memory (NVM) devices with epitaxial (1-x)BaTiO3-xBiFeO3 (x = 0.725) (BT-BFO) film integrated on semiconducting (100) Nb (0.7%) doped SrTiO3 (Nb:STO) substrates. The piezoelectric force microscopy (PFM) measurement at room temperature demonstrated ferroelectricity in the BT-BFO thin film. PFM results also reveal the repeatable polarization inversion by poling, manifesting its potential for read-write operation in NVM devices. The electroforming-free and ferroelectric polarization coupled electrical behaviour demonstrated excellent resistive switching with high retention time, cyclic endurance, and low set/reset voltages. X-ray photoelectron spectroscopy was utilized to determine the band alignment at the BT-BFO and Nb:STO heterojunction, and it exhibited staggered band alignment. This heterojunction is found to behave as an efficient ultraviolet photo-detector with low rise and fall time. The architecture also demonstrates half-wave rectification under low and high input signal frequencies, where the output distortion is minimal. The results provide avenue for an electrical switch that can regulate the pixels in low or high frequency images. Combined this work paves the pathway towards designing future generation low-power ferroelectric based microelectronic devices by merging both electrical and photovoltaic properties of BT-BFO materials.

  5. Atomic Resolution Interfacial Structure of Lead-free Ferroelectric K0.5Na0.5NbO3 Thin films Deposited on SrTiO3

    PubMed Central

    Li, Chao; Wang, Lingyan; Wang, Zhao; Yang, Yaodong; Ren, Wei; Yang, Guang

    2016-01-01

    Oxide interface engineering has attracted considerable attention since the discovery of its exotic properties induced by lattice strain, dislocation and composition change at the interface. In this paper, the atomic resolution structure and composition of the interface between the lead-free piezoelectric (K0.5Na0.5)NbO3 (KNN) thin films and single-crystalline SrTiO3 substrate were investigated by means of scanning transmission electron microscopy (STEM) combining with electron energy loss spectroscopy (EELS). A sharp epitaxial interface was observed to be a monolayer composed of Nb and Ti cations with a ratio of 3/1. The First-Principles Calculations indicated the interface monolayer showed different electronic structure and played the vital role in the asymmetric charge distribution of KNN thin films near the interface. We also observed the gradual relaxation process for the relatively large lattice strains near the KNN/STO interface, which remarks a good structure modulation behavior of KNN thin films via strain engineering. PMID:27886259

  6. Atomic Resolution Interfacial Structure of Lead-free Ferroelectric K0.5Na0.5NbO3 Thin films Deposited on SrTiO3.

    PubMed

    Li, Chao; Wang, Lingyan; Wang, Zhao; Yang, Yaodong; Ren, Wei; Yang, Guang

    2016-11-25

    Oxide interface engineering has attracted considerable attention since the discovery of its exotic properties induced by lattice strain, dislocation and composition change at the interface. In this paper, the atomic resolution structure and composition of the interface between the lead-free piezoelectric (K0.5Na0.5)NbO3 (KNN) thin films and single-crystalline SrTiO3 substrate were investigated by means of scanning transmission electron microscopy (STEM) combining with electron energy loss spectroscopy (EELS). A sharp epitaxial interface was observed to be a monolayer composed of Nb and Ti cations with a ratio of 3/1. The First-Principles Calculations indicated the interface monolayer showed different electronic structure and played the vital role in the asymmetric charge distribution of KNN thin films near the interface. We also observed the gradual relaxation process for the relatively large lattice strains near the KNN/STO interface, which remarks a good structure modulation behavior of KNN thin films via strain engineering.

  7. Piezoelectric Resonator with Two Layers

    NASA Technical Reports Server (NTRS)

    Stephanou, Philip J. (Inventor); Black, Justin P. (Inventor)

    2013-01-01

    A piezoelectric resonator device includes: a top electrode layer with a patterned structure, a top piezoelectric layer adjacent to the top layer, a middle metal layer adjacent to the top piezoelectric layer opposite the top layer, a bottom piezoelectric layer adjacent to the middle layer opposite the top piezoelectric layer, and a bottom electrode layer with a patterned structure and adjacent to the bottom piezoelectric layer opposite the middle layer. The top layer includes a first plurality of electrodes inter-digitated with a second plurality of electrodes. A first one of the electrodes in the top layer and a first one of the electrodes in the bottom layer are coupled to a first contact, and a second one of the electrodes in the top layer and a second one of the electrodes in the bottom layer are coupled to a second contact.

  8. Piezoelectric step-motion actuator

    DOEpatents

    Mentesana; Charles P.

    2006-10-10

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

  9. Evaluation of piezoelectric material properties for a higher power output from energy harvesters with insight into material selection using a coupled piezoelectric-circuit-finite element method.

    PubMed

    Daniels, Alice; Zhu, Meiling; Tiwari, Ashutosh

    2013-12-01

    Piezoelectric material properties have substantial influence on electrical power output from piezoelectric energy harvesters (PEHs). Understanding their influences is the first step in designing effective PEHs to generate higher power outputs. This paper uses a coupled piezoelectric-circuit-finite element method to study the power outputs of different types of piezoelectric materials, including single crystal, polyvinylidene fluoride (PVDF), and soft and hard lead zirconate titanate (PZT) materials. The purpose of this study is to try to gain an understanding of which piezoelectric material property--the elastic compliance s11, the piezoelectric strain constant d31, the piezoelectric stress constant g31, and the relative dielectric constant ϵ(T)r33, and the associated material properties of the d31 × g31, called the figure of merit (FOM), and the coupling coefficient k31--dominates the power output. A rectangular piezoelectric plate under a low-frequency excitation is used to evaluate piezoelectric material properties for a higher power output. It was found that 1) d31 is a more dominant material property over other material properties for higher power output; 2) FOM was more linearly related to the power output than either the k31 or the d31; and 3) ϵ(T)r33 had some role; when the materials have an identical d31; a lower ϵ(T)r33 was preferred. Because of unexplained outliers, no single material parameter was able to be recommended as selection criteria, but combined FOM with d31 parameters is recommended for selection of piezoelectric material for a higher power output from PEHs.

  10. Improved Piezoelectric Loudspeakers And Transducers

    NASA Technical Reports Server (NTRS)

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

    1995-01-01

    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.

  11. High Temperature Piezoelectric Drill

    NASA Technical Reports Server (NTRS)

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

    2012-01-01

    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

  12. Piezoelectric Pulsed Microjets

    DTIC Science & Technology

    2011-04-29

    hydraulic fluid flow within the cylinder head, and hyperelastic stress-strain behavior of the top diaphragm that is coupled to the hydraulic pressure...displacement due to the form of the hyperelastic constitutive equation used to describe its deformation. The input operator, [B(u)](t), is written as a...piezoelectric response. Based on previous experiments, the nylon polymer deforms with the stack without any significant reduction in stack actuator

  13. Piezoelectrically enhanced photocathode

    NASA Technical Reports Server (NTRS)

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

    2009-01-01

    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.

  14. Piezoelectric wind turbine

    NASA Astrophysics Data System (ADS)

    Kishore, Ravi Anant; Priya, Shashank

    2013-03-01

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

  15. Piezoelectric Templates – New Views on Biomineralization and Biomimetics

    PubMed Central

    Stitz, Nina; Eiben, Sabine; Atanasova, Petia; Domingo, Neus; Leineweber, Andreas; Burghard, Zaklina; Bill, Joachim

    2016-01-01

    Biomineralization in general is based on electrostatic interactions and molecular recognition of organic and inorganic phases. These principles of biomineralization have also been utilized and transferred to bio-inspired synthesis of functional materials during the past decades. Proteins involved in both, biomineralization and bio-inspired processes, are often piezoelectric due to their dipolar character hinting to the impact of a template’s piezoelectricity on mineralization processes. However, the piezoelectric contribution on the mineralization process and especially the interaction of organic and inorganic phases is hardly considered so far. We herein report the successful use of the intrinsic piezoelectric properties of tobacco mosaic virus (TMV) to synthesize piezoelectric ZnO. Such films show a two-fold increase of the piezoelectric coefficient up to 7.2 pm V−1 compared to films synthesized on non-piezoelectric templates. By utilizing the intrinsic piezoelectricity of a biotemplate, we thus established a novel synthesis pathway towards functional materials, which sheds light on the whole field of biomimetics. The obtained results are of even broader and general interest since they are providing a new, more comprehensive insight into the mechanisms involved into biomineralization in living nature. PMID:27212583

  16. Piezoelectric Templates – New Views on Biomineralization and Biomimetics

    NASA Astrophysics Data System (ADS)

    Stitz, Nina; Eiben, Sabine; Atanasova, Petia; Domingo, Neus; Leineweber, Andreas; Burghard, Zaklina; Bill, Joachim

    2016-05-01

    Biomineralization in general is based on electrostatic interactions and molecular recognition of organic and inorganic phases. These principles of biomineralization have also been utilized and transferred to bio-inspired synthesis of functional materials during the past decades. Proteins involved in both, biomineralization and bio-inspired processes, are often piezoelectric due to their dipolar character hinting to the impact of a template’s piezoelectricity on mineralization processes. However, the piezoelectric contribution on the mineralization process and especially the interaction of organic and inorganic phases is hardly considered so far. We herein report the successful use of the intrinsic piezoelectric properties of tobacco mosaic virus (TMV) to synthesize piezoelectric ZnO. Such films show a two-fold increase of the piezoelectric coefficient up to 7.2 pm V‑1 compared to films synthesized on non-piezoelectric templates. By utilizing the intrinsic piezoelectricity of a biotemplate, we thus established a novel synthesis pathway towards functional materials, which sheds light on the whole field of biomimetics. The obtained results are of even broader and general interest since they are providing a new, more comprehensive insight into the mechanisms involved into biomineralization in living nature.

  17. Hybrid piezoelectric energy harvesting transducer system

    NASA Technical Reports Server (NTRS)

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

    2008-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Fiedler, Brent Alan

    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

  19. Device simulation of lead-free CH3NH3SnI3 perovskite solar cells with high efficiency

    NASA Astrophysics Data System (ADS)

    Du, Hui-Jing; Wang, Wei-Chao; Zhu, Jian-Zhuo

    2016-10-01

    The lead-free perovskite solar cells (PSCs) have drawn a great deal of research interest due to the Pb toxicity of the lead halide perovskite. CH3NH3SnI3 is a viable alternative to CH3NH3PbX3, because it has a narrower band gap of 1.3 eV and a wider visible absorption spectrum than the lead halide perovskite. The progress of fabricating tin iodide PSCs with good stability has stimulated the studies of these CH3NH3SnI3 based cells greatly. In the paper, we study the influences of various parameters on the solar cell performance through theoretical analysis and device simulation. It is found in the simulation that the solar cell performance can be improved to some extent by adjusting the doping concentration of the perovskite absorption layer and the electron affinity of the buffer and HTM, while the reduction of the defect density of the perovskite absorption layer significantly improves the cell performance. By further optimizing the parameters of the doping concentration (1.3× 1016 cm-3) and the defect density (1× 1015 cm-3) of perovskite absorption layer, and the electron affinity of buffer (4.0 eV) and HTM (2.6 eV), we finally obtain some encouraging results of the J sc of 31.59 mA/cm2, V oc of 0.92 V, FF of 79.99%, and PCE of 23.36%. The results show that the lead-free CH3NH3SnI3 PSC is a potential environmentally friendly solar cell with high efficiency. Improving the Sn2 + stability and reducing the defect density of CH3NH3SnI3 are key issues for the future research, which can be solved by improving the fabrication and encapsulation process of the cell. Project supported by the Graduate Student Education Teaching Reform Project, China (Grant No. JG201512) and the Young Teachers Research Project of Yanshan University, China (Grant No. 13LGB028).

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

    NASA Astrophysics Data System (ADS)

    Wang, Qing

    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 125°C; and aged for 250 hours at 125°C. 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

  1. Characterization of Exposure to Byproducts from Firing Lead Free Frangible Ammunition in an Enclosed, Ventilated Firing Range.

    PubMed

    Grabinski, Christin M; Methner, Mark M; Jackson, Jerimiah M; Moore, Alexander L; Flory, Laura E; Tilly, Trevor; Hussain, Saber M; Ott, Darrin K

    2017-02-26

    U.S. Air Force small arms firing ranges began using copper-based, lead-free frangible ammunition in the early 2000s due to environmental and health concerns related to the use of lead-based ammunition. Exposure assessments at these firing ranges have routinely detected chemicals and metals in amounts much lower than their mass-based occupational exposure limits, yet, instructors report work-related health concerns including respiratory distress, nausea, and headache. The objective of this study at one firing range was to characterize the aerosol emissions produced by weapons during firing events and evaluate the ventilation system's effectiveness in controlling instructor exposure to these emissions. The ventilation system was assessed by measuring the range static air pressure differential and the air velocity at the firing line. Air flow patterns were observed near the firing line. Instructor exposure was sampled using a filter-based air sampling method for metals and a wearable, real-time ultrafine particle counter. Area air sampling was simultaneously performed to characterize the particle size distribution, morphology and composition. In the instructor's breathing zone, the airborne mass concentration of copper was low (range = <1-µg/m(3) to 16-µg/m(3)), yet the ultrafine (nanoscale) particle number concentration increased substantially during each firing event. Ultrafine particles contained some copper and were complex in morphology and composition. The ventilation assessment found that the average velocity across all shooting lanes was acceptable compared to the recommended guideline (20% of the ideal 0.38-m/s (75-ft/min). However, uniform, downrange airflow pattern requirements were not met. These results suggest that the mass-based occupational exposure limits, as applied to this environment, may not be protective enough to eliminate health complaints reported by instructors whose full-time job involves training personnel on weapons that fire lead free

  2. BNT-BT0.08 wires derived from sol-gel precursor and their piezoelectric behavior

    NASA Astrophysics Data System (ADS)

    Cernea, M.; Pintilie, L.; Trupina, L.; Vasile, B. S.; Chirila, C.; Pasuk, I.

    2013-05-01

    Lead-free piezoelectric (Bi0.5Na0.5)0.92Ba0.08TiO3, (abbreviated as BNT-BT0.08) wires were prepared using its corresponding precursor sol and, a polycarbonate template membrane. The polycarbonate membrane used has a thickness of 30 μm and pore diameter of 300 nm. Uniform surface morphology of the wires with average diameter of 145 nm and a length of about 20 μm was obtained when the concentration of the sol was 0.3 M. The ferroelectric and piezoelectric properties of an individual BNT-BT0.08 wire were investigated using the PFM technique. The hysteresis loops between the PFM phase and DC bias and, the characteristic butterfly loops of the PFM amplitude versus DC bias, indicated a ferroelectric and piezoelectric behavior of as-obtained BNT-BT0.08 wires.

  3. Methodology for analyzing stress states during in-situ thermomechanical cycling in individual lead free solder joints using synchrotron radiation

    SciTech Connect

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

    2010-07-22

    To examine how a lead-free solder joint deforms in a thermal cycling environment, both the elastic and plastic stress and strain behavior must be understood. Methods to identify evolution of the internal strain (stress) state during thermal cycling are described. A slice of a package containing a single row of solder joints was thermally cycled from 0 C to 100 C with a period of about 1 h with concurrent acquisition of transmission Laue patterns using synchrotron radiation. These results indicated that most joints are single crystals, with some being multicrystals with no more than a few Sn grain orientations. Laue patterns were analyzed to estimate local strains in different crystal directions at different temperatures during a thermal cycle. While the strains perpendicular to various crystal planes all vary in a similar way, the magnitude of strain varies. The specimens were subsequently given several hundred additional thermal cycles and measured again to assess changes in the crystal orientations. These results show that modest changes in crystal orientations occur during thermal cycling.

  4. Contact angle measurements of Sn-Ag and Sn-Cu lead-free solders on copper substrates

    NASA Astrophysics Data System (ADS)

    Arenas, Mario F.; Acoff, Viola L.

    2004-12-01

    In this study, the contact angles of four lead-free solders, namely, Sn-3.5Ag, Sn-3.5Ag-4.8Bi, Sn-3.8Ag-0.7Cu, and Sn-0.7Cu (wt.%), were measured on copper substrates at different temperatures. Measurements were performed using the sessile-drop method. Contact angles ranging from 30° to 40° after wetting under vacuum with no fluxes and between 10° and 30° with rosin mildly activated (RMA) and rosin activated (RA) fluxes were obtained. The Sn-3.5Ag-4.8Bi exhibited the lowest contact angles, indicating improved wettability with the addition of bismuth. For all soldering alloys, lower contact angles were observed using RMA flux. Intermetallics formed at the solder/Cu interface were identified as Cu6Sn5 adjacent to the solder and Cu3Sn adjacent to the copper substrate. The Cu3Sn intermetallic phase was generally not observed when RMA flux was used. The effect of temperature on contact angle was dependent on the type of flux used.

  5. Effect of B-site isovalent doping on electrical and ferroelectric properties of lead free bismuth titanate ceramics

    NASA Astrophysics Data System (ADS)

    Subohi, Oroosa; Kumar, G. S.; Malik, M. M.; Kurchania, Rajnish

    2016-06-01

    In the present work, zirconium modified bismuth titanate ceramics have been studied as potential lead-free ferroelectric materials over a broad temperature range (RT - 800 °C). Polycrystalline samples of Bi4Ti3-xZrxO12 (x=0.2, 0.4, 0.6) (BZrT) with high electrical resistivity were prepared using the solution combustion technique. The effect of Zr doping on the crystalline structure, ferroelectric properties and electrical conduction characteristics of BZrT ceramics were explored. Addition of zirconium to bismuth titanate enhances its dielectric constant and reduces the loss factor as it introduces orthorhombic distortion in bismuth titanate lattice which is exhibited by the growth along (00_10) lattice plane. Activation energy due to relaxation is found to be greater than that due to conduction thus confirming that electrical conduction in these ceramics is not due to relaxation of dipoles. Remanent polarization of the doped samples increases as the Zirconium content increases.

  6. Liquid-phase diffusion bonding: Temperature effects and solute redistribution in high temperature lead-free composite solders

    SciTech Connect

    Anderson, Iver; Choquette, Stephanie

    2015-05-17

    Liquid-phase diffusion bonding (LPDB) is being studied as the primary phenomena occurring in the development of a high temperature lead-free composite solder paste composed of gas-atomized Cu-10Ni, wt.% (Cu-11Ni, at.%) powder blended with Sn-0.7Cu-0.05Ni-0.01Ge (Sn-1.3Cu-0.1Ni-0.02Ge, at.%) Nihon-Superior SN100C solder powder. Powder compacts were used as a model system. LPDB promotes enhanced interdiffusion of the low-melting alloy matrix with the solid Cu-10Ni reinforcement powder above the matrix liquidus temperature. The initial study involved the effective intermetallic compound (IMC) compositions and microstructures that occur at varying reflow temperatures and times between 250-300°C and 30-60s, respectively. Certain reflow temperatures encourage adequate interdiffusion to form a continuous highly-conductive network throughout the composite solder joints. The diffusion of nickel, in particular, has a disperse pattern that foreshadows the possibility of a highly-conductive low-melting solder that can be successfully utilized at high temperatures.

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

    NASA Astrophysics Data System (ADS)

    Shi, Hongbin; Tian, Cuihua; Ueda, Toshitsugu

    2012-05-01

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

  8. Relaxor nature in lead-free Sr5LaTi3Nb7O30 tetragonal tungsten bronze ceramics

    NASA Astrophysics Data System (ADS)

    Li Zhu, Xiao; Li, Kun; Asif Rafiq, Muhammad; Qiang Liu, Xiao; Ming Chen, Xiang

    2013-09-01

    Lead-free tetragonal tungsten bronze Sr5LaTi3Nb7O30 ceramics were prepared and the correlation of the relaxor nature and crystal structure was studied using dielectric spectroscopy and powder X-ray diffraction. Three dielectric relaxations were observed below the deviation temperature TD ˜ 330 K. Relaxation I and II followed the Vogel-Fulcher law with the freezing temperatures of 189 K and ˜90 K. Low temperature relaxation III, which was first observed in filled tungsten bronze, followed well the Arrhenius law. Dielectric response becomes static below 50 K. Polarization-field (P-E) hysteresis loops were evaluated from 183 K to 298 K. Pr value of 0.41μC/cm2 was observed at 183 K. Deviation of lattice parameter c from the linear contraction and increasing of tetragonality (c/a ratio) were observed below TD, reflecting the structure change during the formation of polar nanoregions and the following freezing process. Opposite tendency was observed below 100 K for all the lattice parameters, corresponding to relaxation III. Generally, the main dielectric relaxation I and II were attributed to flipping and breathing of polar nanoregions along c axis, while the concerted rotations of the oxygen octahedra in the ab plane were suggested as the origin of relaxation III.

  9. Microstructure and In Situ Observations of Undercooling for Nucleation of [beta]-Sn Relevant to Lead-Free Solder Alloys

    SciTech Connect

    Elmer, John W.; Specht, Eliot D.; Kumar, Mukul

    2010-03-16

    Difficult nucleation of {beta}-Sn during solidification of tin and tin-based lead-free solder alloys can result in high degrees of undercooling of the liquid prior to solidification. The undercooling can produce solder joints with large grains, anisotropic behavior, and undesirable mechanical properties. This paper describes our examination of the amount of undercooling of tin on both graphite (non-wetting) and copper (wetting) surfaces using in situ x-ray diffraction. The microstructure was further characterized by optical microscopy, scanning electron microscopy, and electron backscattering diffraction imaging microscopy. Undercoolings as high as 61 C were observed for Sn solidified on graphite, while lower undercoolings, up to 30 C, were observed for Sn solidified on copper. The microstructure of the high purity Sn sample solidified on graphite showed very few grains in the cross-section, while the commercially pure Sn sample solidified with only one grain and was twinned. Tin solidified on copper contained significant amounts of copper in the tin, intermetallic phase formation at the interface, and a eutectic microstructure.

  10. Microstructure and in situ observation of undercooling for nucleation of b-Sn relevant to lead-free solder alloys

    SciTech Connect

    Elmer, J. W.; Specht, Eliot D; Kumar, Mukul

    2010-01-01

    Difficult nucleation of b-Sn during solidification of tin and tin-based lead-free solder alloys can result in high degrees of undercooling of the liquid prior to solidification. The undercooling can produce solder joints with large grains, anisotropic behavior, and undesirable mechanical properties. This paper describes our examination of the amount of undercooling of tin on both graphite (non-wetting) and copper (wetting) surfaces using in situ x-ray diffraction. The microstructure was further characterized by optical microscopy, scanning electron microscopy, and electron backscattering diffraction imaging microscopy. Undercoolings as high as 61C were observed for Sn solidified on graphite, while lower undercoolings, up to 30C, were observed for Sn solidified on copper. The microstructure of the high purity Sn sample solidified on graphite showed very few grains in the cross-section, while the commercially pure Sn sample solidified with only one grain and was twinned. Tin solidified on copper contained significant amounts of copper in the tin, intermetallic phase formation at the interface, and a eutectic microstructure.

  11. Piezoelectric extraction of ECG signal.

    PubMed

    Ahmad, Mahmoud Al

    2016-11-17

    The monitoring and early detection of abnormalities or variations in the cardiac cycle functionality are very critical practices and have significant impact on the prevention of heart diseases and their associated complications. Currently, in the field of biomedical engineering, there is a growing need for devices capable of measuring and monitoring a wide range of cardiac cycle parameters continuously, effectively and on a real-time basis using easily accessible and reusable probes. In this paper, the revolutionary generation and extraction of the corresponding ECG signal using a piezoelectric transducer as alternative for the ECG will be discussed. The piezoelectric transducer pick up the vibrations from the heart beats and convert them into electrical output signals. To this end, piezoelectric and signal processing techniques were employed to extract the ECG corresponding signal from the piezoelectric output voltage signal. The measured electrode based and the extracted piezoelectric based ECG traces are well corroborated. Their peaks amplitudes and locations are well aligned with each other.

  12. High-temperature piezoelectric sensing.

    PubMed

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

    2013-12-20

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

  13. Piezoelectric extraction of ECG signal

    NASA Astrophysics Data System (ADS)

    Ahmad, Mahmoud Al

    2016-11-01

    The monitoring and early detection of abnormalities or variations in the cardiac cycle functionality are very critical practices and have significant impact on the prevention of heart diseases and their associated complications. Currently, in the field of biomedical engineering, there is a growing need for devices capable of measuring and monitoring a wide range of cardiac cycle parameters continuously, effectively and on a real-time basis using easily accessible and reusable probes. In this paper, the revolutionary generation and extraction of the corresponding ECG signal using a piezoelectric transducer as alternative for the ECG will be discussed. The piezoelectric transducer pick up the vibrations from the heart beats and convert them into electrical output signals. To this end, piezoelectric and signal processing techniques were employed to extract the ECG corresponding signal from the piezoelectric output voltage signal. The measured electrode based and the extracted piezoelectric based ECG traces are well corroborated. Their peaks amplitudes and locations are well aligned with each other.

  14. A Piezoelectric Shear Stress Sensor

    NASA Technical Reports Server (NTRS)

    Kim, Taeyang; Saini, Aditya; Kim, Jinwook; Gopalarathnam, Ashok; Zhu, Yong; Palmieri, Frank L.; Wohl, Christopher J.; Jiang, Xiaoning

    2016-01-01

    In this paper, a piezoelectric sensor with a floating element was developed for shear stress measurement. The piezoelectric sensor was designed to detect the pure shear stress suppressing effects of normal stress generated from the vortex lift-up by applying opposite poling vectors to the: piezoelectric elements. The sensor was first calibrated in the lab by applying shear forces and it showed high sensitivity to shear stress (=91.3 +/- 2.1 pC/Pa) due to the high piezoelectric coefficients of PMN-33%PT (d31=-1330 pC/N). The sensor also showed almost no sensitivity to normal stress (less than 1.2 pC/Pa) because of the electromechanical symmetry of the device. The usable frequency range of the sensor is 0-800 Hz. Keywords: Piezoelectric sensor, shear stress, floating element, electromechanical symmetry

  15. High-Temperature Piezoelectric Sensing

    PubMed Central

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

    2014-01-01

    Piezoelectric sensing is of increasing interest for high-temperature applications in aerospace, automotive, power plants and material processing due to its low cost, compact sensor size and simple signal conditioning, in comparison with other high-temperature sensing techniques. This paper presented an overview of high-temperature piezoelectric sensing techniques. Firstly, different types of high-temperature piezoelectric single crystals, electrode materials, and their pros and cons are discussed. Secondly, recent work on high-temperature piezoelectric sensors including accelerometer, surface acoustic wave sensor, ultrasound transducer, acoustic emission sensor, gas sensor, and pressure sensor for temperatures up to 1,250 °C were reviewed. Finally, discussions of existing challenges and future work for high-temperature piezoelectric sensing are presented. PMID:24361928

  16. Origin of Room Temperature Ferromagnetism in Cr-Doped Lead-Free Ferroelectric Bi0.5Na0.5TiO3 Materials

    NASA Astrophysics Data System (ADS)

    Thanh, L. T. H.; Doan, N. B.; Dung, N. Q.; Cuong, L. V.; Bac, L. H.; Duc, N. A.; Bao, P. Q.; Dung, D. D.

    2017-01-01

    The development of multiferroic materials based on lead-free ferroelectric material provides an opportunity to fabricate next-generation electronic devices. In this work, Cr-doped lead-free ferroelectric Bi0.5Na0.5TiO3 materials were synthesized by using the sol-gel method. The optical band gap was reduced from 3.12 eV to 2.12 eV for undoped and 9 mol.% Cr-doped Bi0.5Na0.5TiO3 with the substitution of Cr at the Ti-site. Cr-doped Bi0.5Na0.5TiO3 materials exhibited weak ferromagnetism at room temperature. Saturation magnetization was approximately 0.08 μ B/Cr at 5 K. Our work will facilitate the further understanding of the role of transition metal ferromagnetism in lead-free ferroelectric materials at room temperature.

  17. (100)-Textured KNN-based thick film with enhanced piezoelectric property for intravascular ultrasound imaging

    PubMed Central

    Zhu, Benpeng; Zhang, Zhiqiang; Ma, Teng; Yang, Xiaofei; Li, Yongxiang; Shung, K. Kirk; Zhou, Qifa

    2015-01-01

    Using tape-casting technology, 35 μm free-standing (100)-textured Li doped KNN (KNLN) thick film was prepared by employing NaNbO3 (NN) as template. It exhibited similar piezoelectric behavior to lead containing materials: a longitudinal piezoelectric coefficient (d33) of ∼150 pm/V and an electromechanical coupling coefficient (kt) of 0.44. Based on this thick film, a 52 MHz side-looking miniature transducer with a bandwidth of 61.5% at −6 dB was built for Intravascular ultrasound (IVUS) imaging. In comparison with 40 MHz PMN-PT single crystal transducer, the rabbit aorta image had better resolution and higher noise-to-signal ratio, indicating that lead-free (100)-textured KNLN thick film may be suitable for IVUS (>50 MHz) imaging. PMID:25991874

  18. (100)-Textured KNN-based thick film with enhanced piezoelectric property for intravascular ultrasound imaging

    NASA Astrophysics Data System (ADS)

    Zhu, Benpeng; Zhang, Zhiqiang; Ma, Teng; Yang, Xiaofei; Li, Yongxiang; Shung, K. Kirk; Zhou, Qifa

    2015-04-01

    Using tape-casting technology, 35 μm free-standing (100)-textured Li doped KNN (KNLN) thick film was prepared by employing NaNbO3 (NN) as template. It exhibited similar piezoelectric behavior to lead containing materials: a longitudinal piezoelectric coefficient (d33) of ˜150 pm/V and an electromechanical coupling coefficient (kt) of 0.44. Based on this thick film, a 52 MHz side-looking miniature transducer with a bandwidth of 61.5% at -6 dB was built for Intravascular ultrasound (IVUS) imaging. In comparison with 40 MHz PMN-PT single crystal transducer, the rabbit aorta image had better resolution and higher noise-to-signal ratio, indicating that lead-free (100)-textured KNLN thick film may be suitable for IVUS (>50 MHz) imaging.

  19. Nanoscale mapping of heterogeneity of the polarization reversal in lead-free relaxor-ferroelectric ceramic composites

    NASA Astrophysics Data System (ADS)

    Gobeljic, D.; Shvartsman, V. V.; Belianinov, A.; Okatan, B.; Jesse, S.; Kalinin, S. V.; Groh, C.; Rödel, J.; Lupascu, D. C.

    2016-01-01

    Relaxor/ferroelectric ceramic/ceramic composites have shown to be promising in generating large electromechanical strain at moderate electric fields. Nonetheless, the mechanisms of polarization and strain coupling between grains of different nature in the composites remain unclear. To rationalize the coupling mechanisms we performed advanced piezoresponse force microscopy (PFM) studies of 0.92BNT-0.06BT-0.02KNN/0.93BNT-0.07BT (ergodic/non-ergodic relaxor) composites. PFM is able to distinguish grains of different phases by characteristic domain patterns. Polarization switching has been probed locally, on a sub-grain scale. k-Means clustering analysis applied to arrays of local hysteresis loops reveals variations of polarization switching characteristics between the ergodic and non-ergodic relaxor grains. We report a different set of switching parameters for grains in the composites as opposed to the pure phase samples. Our results confirm ceramic/ceramic composites to be a viable approach to tailor the piezoelectric properties and optimize the macroscopic electromechanical characteristics.Relaxor/ferroelectric ceramic/ceramic composites have shown to be promising in generating large electromechanical strain at moderate electric fields. Nonetheless, the mechanisms of polarization and strain coupling between grains of different nature in the composites remain unclear. To rationalize the coupling mechanisms we performed advanced piezoresponse force microscopy (PFM) studies of 0.92BNT-0.06BT-0.02KNN/0.93BNT-0.07BT (ergodic/non-ergodic relaxor) composites. PFM is able to distinguish grains of different phases by characteristic domain patterns. Polarization switching has been probed locally, on a sub-grain scale. k-Means clustering analysis applied to arrays of local hysteresis loops reveals variations of polarization switching characteristics between the ergodic and non-ergodic relaxor grains. We report a different set of switching parameters for grains in the

  20. 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)

    Plante, Jeannete

    2010-01-01

    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.

  1. Controlling the Color of Lead-Free Red Overglaze Enamels and a Process for Preparing High-Quality Red Paints.

    PubMed

    Hashimoto, Hideki; Inada, Hirofumi; Okazaki, Yuki; Takaishi, Taigo; Fujii, Tatsuo; Takada, Jun

    2016-05-04

    Akae porcelain, an artistic Japanese traditional overglaze ceramic typically known for Kakiemon-style ware, has fascinated porcelain lovers around the world for over 400 years because of the graceful red color displayed by akae that matches so well with white porcelain bodies. In this work, we clarified the factors that control the color of akae and those that are conventionally controlled by artisans based on empirical experience. Inspired by a recent particle-design method, we also developed a practical facile process to prepare red paints that yields high-quality akae. Various akae samples were prepared from a combination of lead-free alkali borosilicate glass frits with different particle sizes and hematite powders with differing dispersibilities. Polarized light microscopy, scanning electron microscopy, and transmission electron microscopy analyses indicate that considering only the dispersibility of hematite powders is not sufficient, but the frit-particle size must be controlled to obtain high-quality akae with a high reflectance value for ≥580 nm visible light. In addition, we developed a process for preparing high-quality red paints that uses a large-particle frit powder and a strongly aggregated-hematite powder, both of which are easily obtainable. The red paint composed of frit, hematite, and the solvent is mixed until the paint is drying. By adding more solvent and repeating this process three times, we obtained high-quality akae with a higher reflectance value than for the akae prepared from a frit with submicron-sized particles and weakly aggregated-hematite powder. On the basis of transmission electron microscopic observations, we consider the red paint to consist of a core/shell-like composite structure of frit and hematite, forming a three-dimensional network in the akae glass layer. The good dispersibility of these particles leads to high-quality akae.

  2. Lead-free Sn-Ag and Sn-Ag-Bi solder powders prepared by mechanical alloying

    NASA Astrophysics Data System (ADS)

    Lai, H. L.; Duh, J. G.

    2003-04-01

    A mechanical alloying (MA) process was used to produce lead-free solder pastes of Sn-3.5Ag and the Sn-3.5Ag-4Bi system. Because of the high energy induced by repeated fracturing and welding, the grinding media played an important role during the MA process. A ceramic container was used to provide stronger impact force, which could induce phase transformation better than a Teflon container. In addition, it was found that 1-cm balls could fracture Bi particles and promote their dissolution into the Sn matrix. On the contrary, the milling process tended to achieve homogeneous mixing when using 3-mm balls. The MA powders, after milling with 3-mm balls, showed a small endothermic peak from the differential scanning calorimetry (DSC) profile at around 138°C, which was the eutectic temperature of Sn-Bi. The melting points of the MA powders in the ceramic container were measured to be 221°C and 203°C, respectively, for Sn-3.5Ag and Sn-3.5Ag-4Bi from the DSC curves. The reduced melting point ensured the complete melting during reflow with a peak temperature of 240°C. The formation of Ag3Sn was also observed from the x-ray diffraction peaks, indicating successful alloying by MA. The solder pastes could, thus, be produced by adding flux into the MA powders. The wetting property of the solder joint was also evaluated. The as-prepared solder pastes on electroless Ni-P/Cu/Si showed good metallurgical bonding with a contact angle less than 20°.

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

    NASA Astrophysics Data System (ADS)

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

    2011-01-01

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

  4. Cs2InAgCl6: A New Lead-Free Halide Double Perovskite with Direct Band Gap.

    PubMed

    Volonakis, George; Haghighirad, Amir Abbas; Milot, Rebecca L; Sio, Weng H; Filip, Marina R; Wenger, Bernard; Johnston, Michael B; Herz, Laura M; Snaith, Henry J; Giustino, Feliciano

    2017-02-16

    A2BB'X6 halide double perovskites based on bismuth and silver have recently been proposed as potential environmentally friendly alternatives to lead-based hybrid halide perovskites. In particular, Cs2BiAgX6 (X = Cl, Br) have been synthesized and found to exhibit band gaps in the visible range. However, the band gaps of these compounds are indirect, which is not ideal for applications in thin film photovoltaics. Here, we propose a new class of halide double perovskites, where the B(3+) and B(+) cations are In(3+) and Ag(+), respectively. Our first-principles calculations indicate that the hypothetical compounds Cs2InAgX6 (X = Cl, Br, I) should exhibit direct band gaps between the visible (I) and the ultraviolet (Cl). Based on these predictions, we attempt to synthesize Cs2InAgCl6 and Cs2InAgBr6, and we succeed to form the hitherto unknown double perovskite Cs2InAgCl6. X-ray diffraction yields a double perovskite structure with space group Fm3̅m. The measured band gap is 3.3 eV, and the compound is found to be photosensitive and turns reversibly from white to orange under ultraviolet illumination. We also perform an empirical analysis of the stability of Cs2InAgX6 and their mixed halides based on Goldschmidt's rules, and we find that it should also be possible to form Cs2InAg(Cl1-xBrx)6 for x < 1. The synthesis of mixed halides will open the way to the development of lead-free double perovskites with direct and tunable band gaps.

  5. Interconnection of thermal parameters, microstructure and mechanical properties in directionally solidified Sn–Sb lead-free solder alloys

    SciTech Connect

    Dias, Marcelino; Costa, Thiago; Rocha, Otávio; Spinelli, José E.; Cheung, Noé; Garcia, Amauri

    2015-08-15

    Considerable effort is being made to develop lead-free solders for assembling in environmental-conscious electronics, due to the inherent toxicity of Pb. The search for substitute alloys of Pb–Sn solders has increased in order to comply with different soldering purposes. The solder must not only meet the expected levels of electrical performance but may also have appropriate mechanical strength, with the absence of cracks in the solder joints. The Sn–Sb alloy system has a range of compositions that can be potentially included in the class of high temperature solders. This study aims to establish interrelations of solidification thermal parameters, microstructure and mechanical properties of Sn–Sb alloys (2 wt.%Sb and 5.5 wt.%Sb) samples, which were directionally solidified under cooling rates similar to those of reflow procedures in industrial practice. A complete high-cooling rate cellular growth is shown to be associated with the Sn–2.0 wt.%Sb alloy and a reverse dendrite-to-cell transition is observed for the Sn–5.5 wt.%Sb alloy. Strength and ductility of the Sn–2.0 wt.%Sb alloy are shown not to be affected by the cellular spacing. On the other hand, a considerable variation in these properties is associated with the cellular region of the Sn–5.5 wt.%Sb alloy casting. - Graphical abstract: Display Omitted - Highlights: • The microstructure of the Sn–2 wt.%Sb alloy is characterized by high-cooling rates cells. • Reverse dendrite > cell transition occurs for Sn–5.5 wt.%Sb alloy: cells prevail for cooling rates > 1.2 K/s. • Sn–5.5 wt.%Sb alloy: the dendritic region occurs for cooling rates < 0.9 K/s. • Sn–5.5 wt.%Sb alloy: tensile properties are improved with decreasing cellular spacing.

  6. Structural, microstructural and thermal properties of lead-free bismuth–sodium–barium–titanate piezoceramics synthesized by mechanical alloying

    SciTech Connect

    Amini, Rasool; Ghazanfari, Mohammad Reza; Alizadeh, Morteza; Ardakani, Hamed Ahmadi; Ghaffari, Mohammad

    2013-02-15

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

  7. Effects of Li content on the phase structure and electrical properties of lead-free (K0.46-x/2Na0.54-x/2Lix)(Nb0.76Ta0.20Sb0.04)O3 ceramics

    NASA Astrophysics Data System (ADS)

    Chang, Yunfei; Yang, Zupei; Hou, Yuting; Liu, Zonghuai; Wang, Zenglin

    2007-06-01

    Lead-free (K0.46-x/2Na0.54-x/2Lix)(Nb0.76Ta0.20Sb0.04)O3 piezoelectric ceramics were prepared by the conventional solid state sintering method without cold-isostatic pressing process. The x-ray diffraction and Raman scattering results show that the phase structure of the ceramics undergoes a transition from pseudocubic to tetragonal phase with increasing x from 0 to 0.10. Significantly enhanced electrical properties (d33=259pC/N, kp=0.42, ɛr=1653, and tan δ =0.027) were obtained in the ceramics with x =0.04 near the morphotropic phase boundary, and only the tetragonal-cubic phase transition was observed above the room temperature in the ɛr-T curve. The temperature stability of the ceramics with x =0.04 was also investigated.

  8. Nanoscale mapping of heterogeneity of the polarization reversal in lead-free relaxor–ferroelectric ceramic composites

    DOE PAGES

    Gobeljic, D.; Shvartsman, V. V.; Belianinov, A.; ...

    2016-01-05

    Relaxor/ferroelectric ceramic/ceramic composites have shown to be promising in generating large electromechanical strain at moderate electric fields. However, the mechanisms of polarization and strain coupling between grains of different nature in the composites remain unclear. To rationalize the coupling mechanisms we performed advanced piezoresponse force microscopy (PFM) studies of 0.92BNT-0.06BT-0.02KNN/0.93BNT-0.07BT (ergodic/non-ergodic relaxor) composites. PFM is able to distinguish grains of different phases by characteristic domain patterns. Polarization switching has been probed locally, on a sub-grain scale. k-Means clustering analysis applied to arrays of local hysteresis loops reveals variations of polarization switching characteristics between the ergodic and non-ergodic relaxor grains. Here,more » we report a different set of switching parameters for grains in the composites as opposed to the pure phase samples. These results confirm ceramic/ceramic composites to be a viable approach to tailor the piezoelectric properties and optimize the macroscopic electromechanical characteristics.« less

  9. Nanoscale mapping of heterogeneity of the polarization reversal in lead-free relaxor–ferroelectric ceramic composites

    SciTech Connect

    Gobeljic, D.; Shvartsman, V. V.; Belianinov, A.; Okatan, B.; Jesse, S.; Kalinin, S. V.; Groh, C.; Rödel, J.; Lupascu, D. C.

    2016-01-05

    Relaxor/ferroelectric ceramic/ceramic composites have shown to be promising in generating large electromechanical strain at moderate electric fields. However, the mechanisms of polarization and strain coupling between grains of different nature in the composites remain unclear. To rationalize the coupling mechanisms we performed advanced piezoresponse force microscopy (PFM) studies of 0.92BNT-0.06BT-0.02KNN/0.93BNT-0.07BT (ergodic/non-ergodic relaxor) composites. PFM is able to distinguish grains of different phases by characteristic domain patterns. Polarization switching has been probed locally, on a sub-grain scale. k-Means clustering analysis applied to arrays of local hysteresis loops reveals variations of polarization switching characteristics between the ergodic and non-ergodic relaxor grains. Here, we report a different set of switching parameters for grains in the composites as opposed to the pure phase samples. These results confirm ceramic/ceramic composites to be a viable approach to tailor the piezoelectric properties and optimize the macroscopic electromechanical characteristics.

  10. Radial Field Piezoelectric Diaphragms

    NASA Technical Reports Server (NTRS)

    Bryant, R. G.; Effinger, R. T., IV; Copeland, B. M., Jr.

    2002-01-01

    A series of active piezoelectric diaphragms were fabricated and patterned with several geometrically defined Inter-Circulating Electrodes "ICE" and Interdigitated Ring Electrodes "ICE". When a voltage potential is applied to the electrodes, the result is a radially distributed electric field that mechanically strains the piezoceramic along the Z-axis (perpendicular to the applied electric field). Unlike other piezoelectric bender actuators, these Radial Field Diaphragms (RFDs) strain concentrically yet afford high displacements (several times that of the equivalent Unimorph) while maintaining a constant circumference. One of the more intriguing aspects is that the radial strain field reverses itself along the radius of the RFD while the tangential strain remains relatively constant. The result is a Z-deflection that has a conical profile. This paper covers the fabrication and characterization of the 5 cm. (2 in.) diaphragms as a function of poling field strength, ceramic thickness, electrode type and line spacing, as well as the surface topography, the resulting strain field and displacement as a function of applied voltage at low frequencies. The unique features of these RFDs include the ability to be clamped about their perimeter with little or no change in displacement, the environmentally insulated packaging, and a highly repeatable fabrication process that uses commodity materials.

  11. Piezoelectric axial flow microvalve

    DOEpatents

    Gemmen, Randall; Thornton, Jimmy; Vipperman, Jeffrey S.; Clark, William W.

    2007-01-09

    This invention is directed to a fuel cell operable with a quantity of fuel and a quantity of an oxidizer to produce electrical power, the fuel cell including a fuel cell body including a labyrinth system structured to permit the fuel and the oxidizer to flow therethrough; at least a first catalyst in fluid communication with the labyrinth; and at least a first microvalve operably disposed within at least a portion of the labyrinth. The microvalve utilizes a deflectable member operable upon the application of a voltage from a voltage source. The microvalve includes an elongated flow channel formed therein and extending substantially longitudinally between the first and second ends to permit substantially longitudinal flow of the fluid therethrough and between the first and second ends; and the deflectable member disposed on the valve body, the deflectable member including at least a first piezoelectric portion that is piezoelectrically operable to deflect the deflectable member between an open position and a closed position upon the application of a voltage, the deflectable member in the closed position being operable to resist the flow of the fluid through the flow channel.

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

    SciTech Connect

    Rohatgi, P.K.

    1997-03-01

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

  13. Shear piezoelectricity in bone at the nanoscale

    NASA Astrophysics Data System (ADS)

    Minary-Jolandan, Majid; Yu, Min-Feng

    2010-10-01

    Recent demonstration of shear piezoelectricity in an isolated collagen fibril, which is the origin of piezoelectricity in bone, necessitates investigation of shear piezoelectric behavior in bone at the nanoscale. Using high resolution lateral piezoresponse force microcopy (PFM), shear piezoelectricity in a cortical bone sample was studied at the nanoscale. Subfibrillar structure of individual collagen fibrils with a periodicity of 60-70 nm were revealed in PFM map, indicating the direct contribution of collagen fibrils to the shear piezoelectricity of bone.

  14. Design Requirements for Amorphous Piezoelectric Polymers

    NASA Technical Reports Server (NTRS)

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

    1999-01-01

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

  15. Dielectric Properties of Piezoelectric Polyimides

    NASA Technical Reports Server (NTRS)

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

    1997-01-01

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

  16. Radiation tolerance of piezoelectric bulk single-crystal aluminum nitride

    SciTech Connect

    David A. Parks; Bernhard R. Tittmann

    2014-07-01

    For practical use in harsh radiation environments, we pose selection criteria for piezoelectric materials for nondestructive evaluation (NDE) and material characterization. Using these criteria, piezoelectric aluminum nitride is shown to be an excellent candidate. The results of tests on an aluminumnitride-based transducer operating in a nuclear reactor are also presented. We demonstrate the tolerance of single-crystal piezoelectric aluminum nitride after fast and thermal neutron fluences of 1.85 × 1018 neutron/cm2 and 5.8 × 1018 neutron/cm2, respectively, and a gamma dose of 26.8 MGy. The radiation hardness of AlN is most evident from the unaltered piezoelectric coefficient d33, which measured 5.5 pC/N after a fast and thermal neutron exposure in a nuclear reactor core for over 120 MWh, in agreement with the published literature value. The results offer potential for improving reactor safety and furthering the understanding of radiation effects on materials by enabling structural health monitoring and NDE in spite of the high levels of radiation and high temperatures, which are known to destroy typical commercial ultrasonic transducers.

  17. High piezoelectric properties of cement piezoelectric composites containing kaolin

    NASA Astrophysics Data System (ADS)

    Pan, Huang Hsing; Yang, Ruei-Hao; Cheng, Yu-Chieh

    2015-04-01

    To obtain high piezoelectric properties, PZT/cement composites with kaolin were fabricated and polarized by 1.5kV/mm electric field for 40 min, where lead zirconate titanate (PZT) inclusion with 50% by volume was used. After the polarization, piezoelectric properties of the composite were measured daily till 100 days. Results indicated that relative dielectric constant (ɛr) and piezoelectric strain constant (d33) increase with aging day, and approach to asymptotic values after 70 days. Temperature treatment to the composite is a dominate factor to enhance piezoelectric properties. The d33 and ɛr values of PZT/cement composites treated at the ambient temperature (23℃) were 57pC/N and 275 at the 70th aging day respectively, and then reached 106pC/N and 455 in turn with 150℃ treatment. The composite contains 4% kaolin having the highest value of d33=111pC/N and ɛr=500 at 90 days because the porosity is the less than the others. Cement piezoelectric composites containing kaolin own the higher d33 and ɛr value, compared with the other reported composites with 50% PZT. The porosity, the electromechanical coupling factor and impedance-frequency spectra of the cement piezoelectric composites were also discussed.

  18. Micromachined Piezoelectric Microspeaker

    NASA Astrophysics Data System (ADS)

    Yi, Seung Hwan; Kim, Eun Sok

    2005-06-01

    A diaphragm-based piezoelectric microspeaker is fabricated on a heavily compressive silicon-nitride film, and is compared to commercial speakers. The largest sound pressure level (SPL) produced by the fabricated microspeaker is 92 dB (when measured 2 mm away from the microspeaker in open field) at around 3 kHz for 6 Vpeak-to-peak input. The microspeaker produces a comparable sound output as a commercial piezo-ceramic and electro-dynamic speaker used in current cellular phones. The keys to this success are as follows: (1) the usage of a diaphragm that has a very high compressive residual stress, high enough to cause the diaphragm to be wrinkled and (2) the usage of high quality ZnO film deposited by two-step deposition technique.

  19. Piezoelectric Rotary Tube Motor

    NASA Technical Reports Server (NTRS)

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

    2011-01-01

    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.

  20. Structural Origins of Silk Piezoelectricity

    PubMed Central

    Yucel, Tuna; Cebe, Peggy

    2012-01-01

    Uniaxially oriented, piezoelectric silk films were prepared by a two-step method that involved: (1) air drying aqueous, regenerated silk fibroin solutions into films, and (2) drawing the silk films to a desired draw ratio. The utility of two different drawing techniques, zone drawing and water immersion drawing were investigated for processing the silk for piezoelectric studies. Silk films zone drawn to a ratio of λ= 2.7 displayed relatively high dynamic shear piezoelectric coefficients of d14 = −1.5 pC/N, corresponding to over two orders of magnitude increase in d14 due to film drawing. A strong correlation was observed between the increase in the silk II, β-sheet content with increasing draw ratio measured by FTIR spectroscopy (Cβ∝ e2.5 λ), the concomitant increasing degree of orientation of β-sheet crystals detected via WAXD (FWHM = 0.22° for λ= 2.7), and the improvement in silk piezoelectricity (d14∝ e2.4 λ). Water immersion drawing led to a predominantly silk I structure with a low degree of orientation (FWHM = 75°) and a much weaker piezoelectric response compared to zone drawing. Similarly, increasing the β-sheet crystallinity without inducing crystal alignment, e.g. by methanol treatment, did not result in a significant enhancement of silk piezoelectricity. Overall, a combination of a high degree of silk II, β-sheet crystallinity and crystalline orientation are prerequisites for a strong piezoelectric effect in silk. Further understanding of the structural origins of silk piezoelectricity will provide important options for future biotechnological and biomedical applications of this protein. PMID:23335872

  1. Piezoelectrically Initiated Pyrotechnic Igniter

    NASA Technical Reports Server (NTRS)

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

    2013-01-01

    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

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

    SciTech Connect

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

    2003-04-30

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

  3. Synthesis and Optical Properties of Lead-Free Cesium Tin Halide Perovskite Quantum Rods with High-Performance Solar Cell Application.

    PubMed

    Chen, Lin-Jer; Lee, Chia-Rong; Chuang, Yu-Ju; Wu, Zhao-Han; Chen, Chienyi

    2016-12-15

    Herein, the fabrication of a lead-free cesium tin halide perovskite produced via a simple solvothermal process is reported for the first time. The resulting CsSnX3 (X = Cl, Br, and I) quantum rods show composition-tunable photoluminescence (PL) emissions over the entire visible spectral window (from 625 to 709 nm), as well as significant tunability of the optical properties. In this study, we demonstrate that through hybrid materials (CsSnX3) with different halides, the system can be tunable in terms of PL. By replacing the halide of the CsSnX3 quantum rods, a power conversion efficiency of 12.96% under AM 1.5 G has been achieved. This lead-free quantum rod replacement has demonstrated to be an effective method to create an absorber layer that increases light harvesting and charge collection for photovoltaic applications in its perovskite phase.

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

    PubMed

    Benito, Sandra; Abrego, Zuriñe; Sánchez, Alicia; Unceta, Nora; Goicolea, M Aranzazu; Barrio, Ramón J

    2015-01-01

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

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

    PubMed

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

    2001-12-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2013-01-01

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

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

    PubMed Central

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

    2001-01-01

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

  8. Cryogenic Piezoelectric Actuator

    NASA Technical Reports Server (NTRS)

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

    2009-01-01

    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.

  9. Synthesis and Properties of Pulse Electrodeposited Lead-Free Tin-Based Sn/ZrSiO4 Nanocomposite Coatings

    NASA Astrophysics Data System (ADS)

    Bhattacharya, Sumit; Sharma, Ashutosh; Das, Siddhartha; Das, Karabi

    2016-03-01

    The Sn-based ZrSiO4 nanocomposite coatings have been synthesized by pulse co-electrodeposition technique from an aqueous electrolyte containing SnCl2·2H2O, C6H17N3O7, Triton X, and varying amounts of nano-sized ZrSiO4 particles (0, 5, 10, 15, 20, 25, 30, and 35 g/L). As-deposited films have been analyzed using X-ray diffraction, scanning electron microscope equipped with an energy dispersive X-ray spectrometer, and transmission electron microscope. The microhardness, wear as well as corrosion property of the coatings have been also evaluated. It is observed that the surface morphology of Sn-ZrSiO4 nanocomposite coatings is strongly dependent on the reinforcement concentration in the electrolyte, and the Sn-ZrSiO4 nanocomposite solder deposited from the electrolyte containing 25 g/L ZrSiO4 yields the highest hardness and the best wear and corrosion property among all the synthesized samples. The whisker growth propensity of the developed Sn-ZrSiO4 nanocomposites has also been examined after 90 days of aging at room temperature and reported here.

  10. Piezoelectric extraction of ECG signal

    PubMed Central

    Ahmad, Mahmoud Al

    2016-01-01

    The monitoring and early detection of abnormalities or variations in the cardiac cycle functionality are very critical practices and have significant impact on the prevention of heart diseases and their associated complications. Currently, in the field of biomedical engineering, there is a growing need for devices capable of measuring and monitoring a wide range of cardiac cycle parameters continuously, effectively and on a real-time basis using easily accessible and reusable probes. In this paper, the revolutionary generation and extraction of the corresponding ECG signal using a piezoelectric transducer as alternative for the ECG will be discussed. The piezoelectric transducer pick up the vibrations from the heart beats and convert them into electrical output signals. To this end, piezoelectric and signal processing techniques were employed to extract the ECG corresponding signal from the piezoelectric output voltage signal. The measured electrode based and the extracted piezoelectric based ECG traces are well corroborated. Their peaks amplitudes and locations are well aligned with each other. PMID:27853180

  11. Radially sandwiched cylindrical piezoelectric transducer

    NASA Astrophysics Data System (ADS)

    Lin, Shuyu; Fu, Zhiqiang; Zhang, Xiaoli; Wang, Yong; Hu, Jing

    2013-01-01

    A new type of radially sandwiched piezoelectric short cylindrical transducer is developed and its radial vibration is studied. The transducer is composed of a solid metal disk, a radially polarized piezoelectric ceramic short tube and a metal tube. The radial vibrations of the solid metal disk, the radially polarized piezoelectric tube and the metal tube are analyzed and their electromechanical equivalent circuits are introduced. Based on the mechanical boundary conditions among the metal disk, the piezoelectric tube and the metal tube, a three-port electromechanical equivalent circuit for the radially sandwiched transducer is obtained and the frequency equation is given. The theoretical relationship of the resonance and anti-resonance frequencies and the effective electromechanical coupling coefficient with the geometrical dimensions is analyzed. The radial vibration of the sandwiched transducer is simulated by using two different numerical methods. It is shown that the analytical resonance and anti-resonance frequencies are in good agreement with the numerically simulated results. The transducer is expected to be used in piezoelectric resonators, actuators and ultrasonic radiators in ultrasonic and underwater sound applications.

  12. Polymer Piezoelectric Transducers for Ultrasonic NDE

    NASA Technical Reports Server (NTRS)

    Bar-Cohen, Yoseph; Xue, Tianji; Lih, Shyh-Shiuh

    1996-01-01

    Piezoelectric polymers are associated with a low noise and inherent damping that makes them very effective receivers as well as broadband transmitters for high frequencies tasks. This paper reviews polymer piezoelectric materials, the origin of their piezoelectric behavior and their applications to ultrasonic NDE.

  13. High Voltage Piezoelectric System for Generating Neutrons

    DTIC Science & Technology

    2013-06-01

    Piezoelectric transformer structural modeling - a review,” Ultrasonics , Ferroelectrics and Frequency Control, IEEE Transactions on, vol. 54, pp...1 High Voltage Piezoelectric System for Generating Neutrons Brady Gall, Student Member, IEEE, Scott D. Kovaleski, Senior Member, IEEE, James A...Compact electrical neutron generators are a desir- able alternative to radioisotope neutron sources. A piezoelectric transformer system is presented

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

    PubMed

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

    2012-06-01

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

  15. Enhanced piezoelectric response of the two-tetragonal-phase-coexisted BiFeO3 epitaxial film

    NASA Astrophysics Data System (ADS)

    Zhao, Yajuan; Yin, Zhigang; Fu, Zhen; Zhang, Xingwang; Zhu, Jingbin; Wu, Jinliang; You, Jingbi

    2017-02-01

    A BiFeO3 epitaxial film composed of two tetragonal phases was deposited on SrTiO3 substrates by using oxygen-deficient La0.3Sr0.7MnO3-δ as the buffer. One of these phases is a high-temperature form of the highly elongated monoclinic type-C BiFeO3, and the other belongs to the strain-distorted version of the rhombohedral phase. The piezoelectric constant d33 of the mixed-phase structure was determined to be 210 pm/V, much larger than that of the pure rhombohedral BiFeO3. Electric-field-induced strain up to 4% was observed, suggesting a strong electromechanical coupling of the film. These results enrich the knowledge on the strain-driven morphotropic phase boundary of BiFeO3, and thereby provide a possible way for future lead-free piezoelectric applications.

  16. Piezoelectric properties and stabilities of CuO-modified Ba(Ti,Zr)O3 ceramics

    NASA Astrophysics Data System (ADS)

    Zheng, P.; Zhang, J. L.; Shao, S. F.; Tan, Y. Q.; Wang, C. L.

    2009-01-01

    Due to the orthorhombic-tetragonal polymorphic phase transition near room temperature, undesirable large temperature dependence of piezoelectric properties is observed over common usage temperature range in BaTiO3 ceramics with high d33 values. Whereas shifting the phase transition temperature upward by partially substituting Ti with Zr is effective in reducing the piezoelectric temperature dependence, serious long-term degradation occurs. However, it is found that this could be overcome by incorporating a small amount of CuO additive. CuO-modified Ba(Ti0.9625Zr0.0375)O3 ceramics possess excellent piezoelectric properties of d33=300 pC/N, kp=0.493, and k33=0.651 with tan δ=0.011, and its kp remains larger than 0.40 in the broad temperature range from -43 to 73 °C and is almost constant between -25 and 55 °C. The results indicate that CuO-modified Ba(Ti,Zr)O3 ceramics are a promising low-cost lead-free material for practical applications.

  17. Method of Fabricating a Piezoelectric Composite Apparatus

    NASA Technical Reports Server (NTRS)

    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

    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.

  18. Piezoelectric materials used in underwater acoustic transducers

    SciTech Connect

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

    2012-07-07

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

  19. Piezoelectric measurement of laser power

    DOEpatents

    Deason, Vance A.; Johnson, John A.; Telschow, Kenneth L.

    1991-01-01

    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.

  20. Cylindrical Piezoelectric Fiber Composite Actuators

    NASA Technical Reports Server (NTRS)

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

    2008-01-01

    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.

  1. Electrocaloric effect and luminescence properties of lanthanide doped (Na{sub 1/2}Bi{sub 1/2})TiO{sub 3} lead free materials

    SciTech Connect

    Zannen, M.; Lahmar, A. E-mail: zdravko.kutnjak@ijs.si; Asbani, B.; El Marssi, M.; Khemakhem, H.; Kutnjak, Z. E-mail: zdravko.kutnjak@ijs.si; Es Souni, M.

    2015-07-20

    Polycrystalline lead-free Sodium Bismuth Titanate (NBT) ferroelectric ceramics doped with rare earth (RE) element are prepared using solid state reaction method. Optical, ferroelectric, and electrocaloric properties were investigated. The introduction of RE{sup 3+} ions in the NBT host lattice shows different light emissions over the wavelength range from visible to near infrared region. The ferroelectric P-E hysteresis loops exhibit an antiferroelectric-like character near room temperature indicating possible existence of a morphotropic phase boundary. The enhanced electrocaloric response was observed in a broad temperature range due to nearly merged phase transitions. Coexistence of optical and electrocaloric properties is very promising for photonics or optoelectronic device applications.

  2. Electrocaloric effect and luminescence properties of lanthanide doped (Na1/2Bi1/2)TiO3 lead free materials

    NASA Astrophysics Data System (ADS)

    Zannen, M.; Lahmar, A.; Asbani, B.; Khemakhem, H.; El Marssi, M.; Kutnjak, Z.; Es Souni, M.

    2015-07-01

    Polycrystalline lead-free Sodium Bismuth Titanate (NBT) ferroelectric ceramics doped with rare earth (RE) element are prepared using solid state reaction method. Optical, ferroelectric, and electrocaloric properties were investigated. The introduction of RE3+ ions in the NBT host lattice shows different light emissions over the wavelength range from visible to near infrared region. The ferroelectric P-E hysteresis loops exhibit an antiferroelectric-like character near room temperature indicating possible existence of a morphotropic phase boundary. The enhanced electrocaloric response was observed in a broad temperature range due to nearly merged phase transitions. Coexistence of optical and electrocaloric properties is very promising for photonics or optoelectronic device applications.

  3. Circuit for Driving Piezoelectric Transducers

    NASA Technical Reports Server (NTRS)

    Randall, David P.; Chapsky, Jacob

    2009-01-01

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

  4. Virus-based piezoelectric energy generation.

    PubMed

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

    2012-05-13

    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.

  5. Virus-based piezoelectric energy generation

    NASA Astrophysics Data System (ADS)

    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

    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.

  6. High Power Piezoelectric Characterization for Piezoelectric Transformer Development

    NASA Astrophysics Data System (ADS)

    Ural, Seyit O.

    The major goal was to develop characterization techniques to identify and define guidelines to manufacture high power density actuators. We particularly aim at improving the strengths of piezoelectric transformers, namely the high efficiency, ease of manufacturing, low electromagnetic noise, and high power to weight ratio resulting in an adaptor application by identifying material limitations, geometrical limitations and offer guidelines to counter drawbacks limiting the power density. There are 3 losses present in piezoelectrics. Namely dielectric, elastic and piezoelectric losses. These losses can be calculated using mechanical quality factors of the resonating piezoelectric actuator. But in order to calculate all three losses, the mechanical quality factor for resonance and anti resonance need to be measured. Although the mechanical quality factor for resonance is conventionally measured, measurements in antiresonance have been ignored. Since there was no unique measurement technique to address antiresonance and resonance Q in one single sweep, in this study constant vibration velocity method was developed. During the constant vibration velocity measurement, the input electrical energy is monitored and significant differences between resonance and antiresonance drives are observed. For the same output work (identical vibration velocity) significant differences in the losses were observed. Thermographic images have shown increasing temperature differences for resonance and antiresonance nodal point temperatures, with higher vibration velocities. The theoretical evaluation identified the difference observed in the mechanical quality factors at resonance and antiresonance to stem from the piezoelectric loss. In order to investigate losses in the absence of thermal effects a transient characterization technique was adopted. The burst technique, originally developed for characterization of the mechanical quality factor at resonance, has been modified with a switch

  7. Design and Development for Capacitive Humidity Sensor Applications of Lead-Free Ca,Mg,Fe,Ti-Oxides-Based Electro-Ceramics with Improved Sensing Properties via Physisorption

    PubMed Central

    Tripathy, Ashis; Pramanik, Sumit; Manna, Ayan; Bhuyan, Satyanarayan; Azrin Shah, Nabila Farhana; Radzi, Zamri; Abu Osman, Noor Azuan

    2016-01-01

    Despite the many attractive potential uses of ceramic materials as humidity sensors, some unavoidable drawbacks, including toxicity, poor biocompatibility, long response and recovery times, low sensitivity and high hysteresis have stymied the use of these materials in advanced applications. Therefore, in present investigation, we developed a capacitive humidity sensor using lead-free Ca,Mg,Fe,Ti-Oxide (CMFTO)-based electro-ceramics with perovskite structures synthesized by solid-state step-sintering. This technique helps maintain the submicron size porous morphology of the developed lead-free CMFTO electro-ceramics while providing enhanced water physisorption behaviour. In comparison with conventional capacitive humidity sensors, the presented CMFTO-based humidity sensor shows a high sensitivity of up to 3000% compared to other materials, even at lower signal frequency. The best also shows a rapid response (14.5 s) and recovery (34.27 s), and very low hysteresis (3.2%) in a 33%–95% relative humidity range which are much lower values than those of existing conventional sensors. Therefore, CMFTO nano-electro-ceramics appear to be very promising materials for fabricating high-performance capacitive humidity sensors. PMID:27455263

  8. Low electric-field driven ultrahigh electrostrains in Sb-substituted (Na,K)NbO{sub 3} lead-free ferroelectric ceramics

    SciTech Connect

    Fu, Jian; Zuo, Ruzhong E-mail: rzzuo@hotmail.com; Qi, He; Zhang, Chen; Li, Jingfeng; Li, Longtu

    2014-12-15

    Lead-free (Na{sub 0.52}K{sub 0.48})(Nb{sub 1−y}Sb{sub y})O{sub 3} (NKNS{sub y}) ferroelectric ceramics were reported to exhibit an ultrahigh electrostrain (dynamic d{sub 33}* (=S/E) of 800–1100 pm/V) in a relatively low driving electric field range (1–4 kV/mm). As evidenced by in-situ synchrotron x-ray diffraction and dielectric measurements, the mechanism of generating large strains was ascribed to both the low-field induced reversible rhombohedral-monoclinic phase transition (1–2 kV/mm) and the enhanced domain switching (2–4 kV/mm) owing to the normal to relaxor phase transformation, which contribute to ∼62% and ∼38% of the total strain, respectively. The results indicate that the NKNS{sub y} compositions would have excellent potentials for applications of lead-free actuator ceramics.

  9. 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

    Fuse, Masaaki; Tsunemi, Kiyotaka

    2012-11-01

    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.

  10. Electrocaloric effect and energy storage in lead free Gd0.02Na0.48Bi0.5TiO3 ceramic

    NASA Astrophysics Data System (ADS)

    Zannen, M.; Lahmar, A.; Kutnjak, Z.; Belhadi, J.; Khemakhem, H.; El Marssi, M.

    2017-04-01

    The electrocaloric effect (EC) was investigated in the ferroelectric lead-free Na1/2(Bi0.98 Gd0.02)1/2TiO3 (GdNBT) ceramics. A pure perovskite structure was observed by the X-ray diffraction in GdNBT ceramics synthesized by a solid-state reaction method. Dielectric measurements revealed the existence of different ferroelectric and antiferroelectric transformations in this material. Based on the temperature dependence of P-E loops, reversible electrocaloric temperature changes of about ΔT = 0.75 K at the electric field of 90 kV/cm and the EC responsivity ΔT/ΔE ≈ 0.08 × 10-6 K m V-1 were obtained in the GdNBT ceramics. The energy-storage density W = 0.85 J cm-3 and the associated efficiency (η = 65%) at 413 K were determined from the P-E loops data. The simultaneous existence of EC responsivity and energy-storage density makes GdNBT very promising lead-free material and opens a great potential for its application in electronic devices.

  11. Lead free CH3NH3SnI3 perovskite thin-film with p-type semiconducting nature and metal-like conductivity

    NASA Astrophysics Data System (ADS)

    Iefanova, Anastasiia; Adhikari, Nirmal; Dubey, Ashish; Khatiwada, Devendra; Qiao, Qiquan

    2016-08-01

    Lead free CH3NH3SnI3 perovskite thin film was prepared by low temperature solution processing and characterized using current sensing atomic force microscopy (CS-AFM). Analysis of electrical, optical, and optoelectrical properties reveals unique p-type semiconducting nature and metal like conductivity of this material. CH3NH3SnI3 film also showed a strong absorption in visible and near infrared spectrum with absorption onset of 1.3 eV. X-ray Diffraction analysis and scanning electron microscopy (SEM) confirmed a structure of this compound and uniform film formation. The morphology, film uniformity, light harvesting and electrical properties strongly depend on preparation method and precursor solution. CH3NH3SnI3 films prepared based on dimethylformamide (DMF) showed higher crystallinity and light harvesting capability compared to the film based on combination of dimethyl sulfoxide (DMSO) with gamma-butyrolactone (GBL). Local photocurrent mapping analysis showed that CH3NH3SnI3 can be used as an active layer and have a potential to fabricate lead free photovoltaic devices.

  12. Piezoelectric Power Requirements for Active Vibration Control

    NASA Technical Reports Server (NTRS)

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

    1997-01-01

    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.

  13. Coupled improvement between thermoelectric and piezoelectric materials

    NASA Astrophysics Data System (ADS)

    Montgomery, David; Hewitt, Corey; Dun, Chaochao; Carroll, David

    A novel coupling effect in a thermoelectric and piezoelectric meta-structure is discussed. Thermo-piezoelectric generators (TPEGs) exhibit a synergistic effect that amplifies output voltage, and has been observed to increase piezoelectric voltages over 500% of initial values a time dependent thermoelectric/pyroelectric effect. The resulting improvement in voltage has been observed in carbon nanotubes as well as inorganics such as two-dimensional Bismuth Selenide platelets and Telluride nanorods thin-film thermoelectrics. TPEGs are built by integrating insulating layers of polyvinylidene fluoride (PVDF) piezoelectric films between flexible thin film p-type and n-type thermoelectrics. The physical phenomena arising in the interaction between thermoelectric and piezoelectrics is discussed and a model is presented to quantify the expected coupling voltage as a function of stress, thermal gradient, and different thermoelectric materials. TPEG are ideal to capture waste heat and vibrational energy while creating larger voltages and minimizing space when compared with similar thermoelectric or piezoelectric generators.

  14. Heartbeat detection system using piezoelectric transducer

    NASA Astrophysics Data System (ADS)

    Hamonangan, Yosua; Purnamaningsih, Wigajatri

    2017-02-01

    This paper presents a simple piezoelectric based heartbeat detection system. The signal produced by the piezoelectric will undergo signal conditioning and then converted into digital data by Arduino Nano. Using serial communication, the data will be sent to a computer for display and further analysis. The detection of heartbeat is carried out on three locations; wrist, chest, and diaphragm. From the measurement results, it is shown that the system work best when the piezoelectric is placed on wrist.

  15. Additional Drive Circuitry for Piezoelectric Screw Motors

    NASA Technical Reports Server (NTRS)

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

    2004-01-01

    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.

  16. Circular piezoelectric bender laser tuners

    NASA Technical Reports Server (NTRS)

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

    1972-01-01

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

  17. Piezoelectric Measurement Of Bulk Modulus

    NASA Technical Reports Server (NTRS)

    Butler, Barry L.

    1992-01-01

    In method of measuring bulk modulus of elasticity of elastomeric material, piezoelectric crystals of various sizes and energized by alternating voltage embedded in material. Concept demonstrated in test cell in which piezoelectric crystal mounted either unconstrained or between two rubber pads and connected as actuator in loud-speaker. The 1-in. diameter crystal excited with 24 Vac at 60 Hz. When crystal was unconstrained, it drew current of 0.8 mA. When crystal was constrained between rubber pads, current fell to 0.65 mA. Low current, minimal heating, and absence of arcing makes technique suitable for measurement of bulk moduli of elasticity of flammable or explosive rubbery materials.

  18. A Piezoelectric Cryogenic Heat Switch

    NASA Technical Reports Server (NTRS)

    Jahromi, Amir E.; Sullivan, Dan F.

    2014-01-01

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

  19. Elastodynamic Impact into Piezoelectric Media

    DTIC Science & Technology

    2014-09-01

    code, COMSOL Multiphysics. Numerical inverse Laplace transform; modified Dubner-Abate-Crump algorithm; impact boundary condition; FDTD; COMSOL ...code, COMSOL Multiphysics.13 The FDTD code was developed by Raymond A 1 Wildman and the COMSOL simulations were performed by David A Hopkins to compare...jump given by the expression sjump. Figs. 2, 3, and 4 also illustrate solutions to the piezoelectric impact problem using a FDTD method and COMSOL

  20. Polarization and Characterization of Piezoelectric Polymers

    NASA Technical Reports Server (NTRS)

    Bodiford, Hollie N.

    1995-01-01

    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.

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

    SciTech Connect

    Zhou, Bite; Muralidharan, Govindarajan; Kurumaddali, Nalini Kanth; Parish, Chad M; Leslie, Dr Scott; Bieler, T. R.

    2014-01-01

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

  2. Energy storage property in lead free gd doped Na1/2Bi1/2TiO3 ceramics

    NASA Astrophysics Data System (ADS)

    Zannen, Moneim; Lahmar, Abdelilah; Khemakhem, Hamadi; El Marssi, Mimoun

    2016-11-01

    The Effect of Gadolinium ion incorporation on structure, dielectric and ferroelectric properties of lead-free Na1/2Bi1/2TiO3 (NBT) ceramic was investigated. X-ray diffraction allowed the identification of a pure phase isostructural to NBT. Dielectric measurements showed more pronounced anomalies in the range of depolarization temperature when Gd was added. Antiferroelectric-like behavior with a double pinched hysteresis loop was observed versus temperature in the doped phase. The energy-storage density (W) was calculated using the P-E loops data and was found to vary from 0.45 J cm-3 at room temperature to 0.85 J cm-3 at 413 K, which is promising for energy storage application.

  3. Giant electrocaloric effect in lead-free Ba0.94Ca0.06Ti1-xSnxO3 ceramics with tunable Curie temperature

    NASA Astrophysics Data System (ADS)

    Wang, Xiangjian; Tian, Fang; Zhao, Chunlin; Wu, Jiagang; Liu, Yang; Dkhil, Brahim; Zhang, Ming; Gao, Zhipeng; Lou, Xiaojie

    2015-12-01

    Electrocaloric effect in lead-free Ba0.94Ca0.06Ti1-xSnxO3 ceramics is studied using an indirect method. The Ba0.94Ca0.06Ti0.875Sn0.125O3 ceramic located near a multi-phase point shows best electrocaloric performance, which provides further experimental evidence for optimizing electrocaloric properties through constructing multiphase coexistence. Giant electrocaloric efficiency (˜0.4 K mm/kV) is achieved in this ceramic at about room temperature at a low electric field of 6 kV/cm. While large electrocaloric temperature (˜0.63 K) is obtained by further enhancing electric field (20 kV/cm), a decrease in electrocaloric efficiency (0.32 K mm/kV) is simultaneously observed, which is attributed to phase transition from first-order to more diffusive second-order under higher electric field.

  4. Large electrocaloric effect in lead-free K0.5Na0.5NbO3-SrTiO3 ceramics

    NASA Astrophysics Data System (ADS)

    Koruza, J.; Rožič, B.; Cordoyiannis, G.; Malič, B.; Kutnjak, Z.

    2015-05-01

    The electrocaloric effect (ECE), i.e., the adiabatic temperature change ΔTEC, of the lead-free relaxor ferroelectric 0.85K0.5Na0.5NbO3-0.15SrTiO3 (KNN-STO) ceramics is investigated. The ECE data obtained by a direct method show the existence of a large ECE near the temperature of the dielectric permittivity maximum. Due to the high break-down electric field, a large ΔTEC exceeding 1.2 K at 300 K and 1.9 K at 340 K was observed at 159 kV/cm in a broad temperature range of 80 K. Such a high ECE response near the room temperature is comparable to that found in lead-based ceramic materials, thus making KNN-STO a strong candidate to replace lead-based materials in future electrocaloric applications.

  5. Phase transitions and electrical behavior of lead-free (K0.50Na0.50)NbO3 thin film

    NASA Astrophysics Data System (ADS)

    Wu, Jiagang; Wang, John

    2009-09-01

    Lead-free (K0.50Na0.50)NbO3 (KNN) thin films with a high degree of (100) preferred orientation were deposited on the SrRuO3-buffered SrTiO3(100) substrate by off-axis radio frequency magnetron sputtering. They possess lower phase transition temperatures (To-t˜120 °C and Tc˜310 °C), as compared to those of KNN bulk ceramic (To-t˜190 °C and Tc˜400 °C). They also demonstrate enhanced ferroelectric behavior (e.g., 2Pr=24.1 μc/cm2) and fatigue endurance, together with a lower dielectric loss (tan δ ˜0.017) and a lower leakage current, as compared to the bulk ceramic counterpart. Oxygen vacancies are shown to be involved in the conduction of the KNN thin film.

  6. 3D modeling of void nucleation and initial void growth due to Tin diffusion as a result of electromigration in polycrystalline lead-free solders

    NASA Astrophysics Data System (ADS)

    Karunakaran, Deepak

    Electromigration (EM) has been a serious reliability concern in microelectronics packaging for close to half a century now. Whenever the challenges of EM are overcome newer complications arise such as the demand for better performance due to increased miniaturization of semiconductor devices or the problems faced due to undesirable properties of lead-free solders. The motivation for the work is that there exists no fully computational modeling study on EM damage in lead-free solders (and also in lead-based solders). Modeling techniques such as one developed here can give new insights on effects of different grain features and offer high flexibility in varying parameters and study the corresponding effects. In this work, a new computational approach has been developed to study void nucleation and initial void growth in solders due to metal atom diffusion. It involves the creation of a 3D stochastic mesoscale model of the microstructure of a polycrystalline Tin structure. The next step was to identify regions of current crowding or 'hot-spots'. This was done through solving a finite difference scheme on top of the 3D structure. The nucleation of voids due to atomic diffusion from the regions of current crowding was modeled by diffusion from the identified hot-spot through a rejection free kinetic Monte-Carlo scheme. This resulted in the net movement of atoms from the cathode to the anode. The above steps of identifying the hotspot and diffusing the atoms at the hotspot were repeated and this lead to the initial growth of the void. This procedure was studied varying different grain parameters. In the future, the goal is to explore the effect of more grain parameters and consider other mechanisms of failure such as the formation of intermetallic compounds due to interstitial diffusion and dissolution of underbump metallurgy.

  7. Novel optically active lead-free relaxor ferroelectric (Ba0.6Bi0.2Li0.2)TiO3

    NASA Astrophysics Data System (ADS)

    Borkar, Hitesh; Rao, Vaibhav; Dutta, Soma; Barvat, Arun; Pal, Prabir; Tomar, M.; Gupta, Vinay; Scott, J. F.; Kumar, Ashok

    2016-07-01

    We discovered a near-room-temperature lead-free relaxor-ferroelectric (Ba0.6Bi0.2Li0.2)TiO3 (BBLT) having A-site compositionally disordered ABO3 perovskite structure. Microstructure-property relations revealed that the chemical inhomogeneities and development of local polar nano-regions (PNRs) are responsible for dielectric dispersion as a function of probe frequencies and temperatures. Rietveld analysis indicates mixed crystal structure with 80% tetragonal structure (space group P4mm) and 20% orthorhombic structure (space group Amm2), which is confirmed by the high resolution transmission electron diffraction (HRTEM). Dielectric constant and tangent loss dispersion with and without illumination of light obey nonlinear Vogel-Fulcher (VF) relations. The material shows slim polarization-hysteresis (P-E) loops and excellent displacement coefficients (d 33 ~ 233 pm V-1) near room temperature, which gradually diminish near the maximum dielectric dispersion temperature (T m ). The underlying physics for light-sensitive dielectric dispersion was probed by x-ray photon spectroscopy (XPS), which strongly suggests that mixed valence of bismuth ions, especially Bi5+ ions, comprise most of the optically active centers. Ultraviolet photoemission measurements showed most of the Ti ions are in 4 +  states and sit at the centers of the TiO6 octahedra; along with asymmetric hybridization between O 2p and Bi 6s orbitals, this appears to be the main driving force for net polarization. This BBLT material may open a new path for environmental friendly lead-free relaxor-ferroelectric research.

  8. High Performance Flexible Piezoelectric Nanogenerators based on BaTiO3 Nanofibers in Different Alignment Modes.

    PubMed

    Yan, Jing; Jeong, Young Gyu

    2016-06-22

    Piezoelectric nanogenerators, harvesting energy from mechanical stimuli in our living environments, hold great promise to power sustainable self-sufficient micro/nanosystems and mobile/portable electronics. BaTiO3 as a lead-free material with high piezoelectric coefficient and dielectric constant has been widely examined to realize nanogenerators, capacitors, sensors, etc. In this study, polydimethylsiloxane (PDMS)-based flexible composites including BaTiO3 nanofibers with different alignment modes were manufactured and their piezoelectric performance was examined. For the study, BaTiO3 nanofibers were prepared by an electrospinning technique utilizing a sol-gel precursor and following calcination process, and they were then aligned vertically or horizontally or randomly in PDMS matrix-based nanogenerators. The morphological structures of BaTiO3 nanofibers and their nanogenerators were analyzed by using SEM images. The crystal structures of the nanogenerators before and after poling were characterized by X-ray diffraction. The dielectric and piezoelectric properties of the nanogenerators were investigated as a function of the nanofiber alignment mode. The nanogenerator with BaTiO3 nanofibers aligned vertically in the PDMS matrix sheet achieved high piezoelectric performance of an output power of 0.1841 μW with maximum voltage of 2.67 V and current of 261.40 nA under a low mechanical stress of 0.002 MPa, in addition to a high dielectric constant of 40.23 at 100 Hz. The harvested energy could thus power a commercial LED directly or be stored into capacitors after rectification.

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

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

    Compared with the traditional actuator of machinery and electricity, the piezoelectric actuator has the advantages of a compact structure, small volume, no mechanical friction, athermancy and no electromagnetic interference. Therefore, it has high application value in the fields of MEMS, bioengineering, medical science and so on. This article draws conclusions from the influence of multiple piezoelectric effects on the physical parameters (dielectric coefficient, equivalent capacity, energy conversion and piezoelectric coefficient) of piezoelectric actuators. These data from theoretical and experimental research show the following: (1) The rate between the dielectric coefficient of piezoelectric in mechanical freedom and clamping is obtained from the secondary direct piezoelectric effect, which enhances the dielectric property, increases the dielectric coefficient and decreases the coefficient of dielectric isolation; (2) Under external field, En ( ex ) = E 1 , exterior stress T = 0, that is to say, under the boundary condition of mechanical freedom, piezoelectric can store electric energy and elasticity, which obtains power density, elastic density and an electromechanical coupling factor; (3) According to the piezoelectric strain Si ( 1 ) , piezoelectric displacement Dm ( 2 ) and piezoelectric strain Si ( 3 ) of multiple piezoelectric effects, when the dielectric coefficient of the first converse piezoelectric effect ɛ33 is 1326 and the dielectric coefficient of the secondary direct piezoelectric effect increases to 3336, the dielectric coefficient of the ceramic chip increases. When the piezoelectric coefficient of the first converse piezoelectric effect d33 is 595 and the piezoelectric coefficient of the secondary direct piezoelectric effect decreases to 240, the piezoelectric coefficient of the ceramic chip will decrease. It is of major significance both in the applications and in basic theory to research the influence of multiple piezoelectric effects on the

  10. Effects of BaO on the structure and electrical properties of 0.95K0.5Na0.5(Nb0.94Sb0.06)O3 0.05LiTaO3 lead-free ceramics

    NASA Astrophysics Data System (ADS)

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

    2007-11-01

    Lead-free ceramics 0.95K0.5Na0.5(Nb0.94Sb0.06)O3-0.05 LiTaO3 + xmol%BaO (0 <= x <= 3.00) have been fabricated by an ordinary sintering technique. The results of x-ray diffraction show that the ceramic with a perovskite structure changes from tetragonal phase to pseudocubic phase by increasing the doping level of Ba, and the ceramics with 1.00 < x < 1.50 contain both the tetragonal and the pseudocubic phases at room temperature. After the doping with Ba, the grain growth is inhibited, the ferroelectric-paraelectric phase transition temperature (Tc) is decreased, and a diffuse phase transition is induced. The ferroelectric properties (Pr and Ec) show a slight decrease with increasing x up to 1.25, and then become weakened significantly. Because of the coexistence of the tetragonal and pseudocubic phases, the piezoelectric and dielectric properties of the ceramics with 1.00 < x < 1.50 are enhanced significantly. The ceramic with x = 1.25 exhibits the optimum properties: d33 = 261 pC N-1, kP = 0.52, kt = 0.46, ɛr = 1503, tan δ = 2.5% and Tc = 314 °C. Our results have also demonstrated that the ceramics are non-deliquescent.

  11. A Dynamic Analysis of Piezoelectric Strained Elements.

    DTIC Science & Technology

    1992-12-01

    of Piezoelectricity , Oxford Univ.Press, Oxford (1990). E38] T.C.Ting, "Dynamic response of composites", Appl. Mechs.Rev., vol. 33, no.12, Dp.1629-16...Plenum Press, New York (1969). 276 [36] J.Zelenka, Piezoelectric Resonators and their Applications, Elsevier, Amsterdam (1986). [37] T.Ikeda, Fundamentals

  12. Piezoelectric and electrostrictive materials for transducer applications

    NASA Astrophysics Data System (ADS)

    Cross, L. E.; Newnham, R. E.; Barsch, G. R.; Biggers, J. V.

    1985-05-01

    This report covers work accomplished on the second year of contract No. N00014-82-K0339 for the study of Piezoelectric and Electrostrictive Materials for Transducer Applications. The work accomplished covers a rather wide range of topics and for convenience, it is divided into four major sub-topics: (1) composite materials, (2) electrostriction, (3) conventional piezoelectrics, and (4) preparative studies.

  13. High temperature, high power piezoelectric composite transducers.

    PubMed

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

    2014-08-08

    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.

  14. Experiments to Demonstrate Piezoelectric and Pyroelectric Effects

    ERIC Educational Resources Information Center

    Erhart, Jirí

    2013-01-01

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

  15. LC Circuits for Diagnosing Embedded Piezoelectric Devices

    NASA Technical Reports Server (NTRS)

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

    2005-01-01

    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.

  16. High Temperature, High Power Piezoelectric Composite Transducers

    PubMed Central

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

    2014-01-01

    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

  17. Orthotropic Piezoelectricity in 2D Nanocellulose

    NASA Astrophysics Data System (ADS)

    García, Y.; Ruiz-Blanco, Yasser B.; Marrero-Ponce, Yovani; Sotomayor-Torres, C. M.

    2016-10-01

    The control of electromechanical responses within bonding regions is essential to face frontier challenges in nanotechnologies, such as molecular electronics and biotechnology. Here, we present Iβ-nanocellulose as a potentially new orthotropic 2D piezoelectric crystal. The predicted in-layer piezoelectricity is originated on a sui-generis hydrogen bonds pattern. Upon this fact and by using a combination of ab-initio and ad-hoc models, we introduce a description of electrical profiles along chemical bonds. Such developments lead to obtain a rationale for modelling the extended piezoelectric effect originated within bond scales. The order of magnitude estimated for the 2D Iβ-nanocellulose piezoelectric response, ~pm V‑1, ranks this material at the level of currently used piezoelectric energy generators and new artificial 2D designs. Such finding would be crucial for developing alternative materials to drive emerging nanotechnologies.

  18. Orthotropic Piezoelectricity in 2D Nanocellulose

    PubMed Central

    García, Y.; Ruiz-Blanco, Yasser B.; Marrero-Ponce, Yovani; Sotomayor-Torres, C. M.

    2016-01-01

    The control of electromechanical responses within bonding regions is essential to face frontier challenges in nanotechnologies, such as molecular electronics and biotechnology. Here, we present Iβ-nanocellulose as a potentially new orthotropic 2D piezoelectric crystal. The predicted in-layer piezoelectricity is originated on a sui-generis hydrogen bonds pattern. Upon this fact and by using a combination of ab-initio and ad-hoc models, we introduce a description of electrical profiles along chemical bonds. Such developments lead to obtain a rationale for modelling the extended piezoelectric effect originated within bond scales. The order of magnitude estimated for the 2D Iβ-nanocellulose piezoelectric response, ~pm V−1, ranks this material at the level of currently used piezoelectric energy generators and new artificial 2D designs. Such finding would be crucial for developing alternative materials to drive emerging nanotechnologies. PMID:27708364

  19. Orthotropic Piezoelectricity in 2D Nanocellulose.

    PubMed

    García, Y; Ruiz-Blanco, Yasser B; Marrero-Ponce, Yovani; Sotomayor-Torres, C M

    2016-10-06

    The control of electromechanical responses within bonding regions is essential to face frontier challenges in nanotechnologies, such as molecular electronics and biotechnology. Here, we present Iβ-nanocellulose as a potentially new orthotropic 2D piezoelectric crystal. The predicted in-layer piezoelectricity is originated on a sui-generis hydrogen bonds pattern. Upon this fact and by using a combination of ab-initio and ad-hoc models, we introduce a description of electrical profiles along chemical bonds. Such developments lead to obtain a rationale for modelling the extended piezoelectric effect originated within bond scales. The order of magnitude estimated for the 2D Iβ-nanocellulose piezoelectric response, ~pm V(-1), ranks this material at the level of currently used piezoelectric energy generators and new artificial 2D designs. Such finding would be crucial for developing alternative materials to drive emerging nanotechnologies.

  20. Giant piezoelectricity on Si for hyperactive MEMS.

    PubMed

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

    2011-11-18

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

  1. Multistage Force Amplification of Piezoelectric Stacks

    NASA Technical Reports Server (NTRS)

    Xu, Tian-Bing (Inventor); Siochi, Emilie J. (Inventor); Zuo, Lei (Inventor); Jiang, Xiaoning (Inventor); Kang, Jin Ho (Inventor)

    2015-01-01

    Embodiments of the disclosure include an apparatus and methods for using a piezoelectric device, that includes an outer flextensional casing, a first cell and a last cell serially coupled to each other and coupled to the outer flextensional casing such that each cell having a flextensional cell structure and each cell receives an input force and provides an output force that is amplified based on the input force. The apparatus further includes a piezoelectric stack coupled to each cell such that the piezoelectric stack of each cell provides piezoelectric energy based on the output force for each cell. Further, the last cell receives an input force that is the output force from the first cell and the last cell provides an output apparatus force In addition, the piezoelectric energy harvested is based on the output apparatus force. Moreover, the apparatus provides displacement based on the output apparatus force.

  2. Flutter suppression via piezoelectric actuation

    NASA Technical Reports Server (NTRS)

    Heeg, Jennifer

    1991-01-01

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

  3. A piezoelectric cryogenic heat switch.

    PubMed

    Jahromi, Amir E; Sullivan, Dan F

    2014-06-01

    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.

  4. Using Diffusion Bonding in Making Piezoelectric Actuators

    NASA Technical Reports Server (NTRS)

    Sager, Frank E.

    2003-01-01

    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

  5. Biocompatible nanogenerators through high piezoelectric coefficient 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 nanowires for in-vivo applications.

    PubMed

    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

    2014-11-26

    Lead-free BZT-BCT (0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)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.

  6. Structural manipulation and tailoring of dielectric properties in SrTi1−xFexTaxO3 perovskites: Design of new lead free relaxors

    PubMed Central

    Shukla, R.; Patwe, S. J.; Deshpande, S. K.; Achary, S. N.; Krishna, P. S. R.; Shinde, A. B.; Gopalakrishnan, J.; Tyagi, A. K.

    2016-01-01

    We report composition dependent structure evolution from SrTiO3 to SrFe0.5Ta0.5O3 by powder X-ray and neutron diffraction studies of SrTi1−2xFexTaxO3 (0.00 ≤ × ≤ 0.50) compositions. Structural studies reveal cubic (Pm3m) perovskite-type structure of the parent SrTiO3 for x up to 0.075 and cation disordered orthorhombic (Pbnm) perovskite-type structure for x ≥ 0.33. A biphasic region consisting of a mixture of cubic and orthorhombic structures is found in the range for 0.10 ≤ × ≤ 0.25. Dielectric studies reveal transformation from a normal dielectric to relaxor like properties with increasing Fe3+ and Ta5+ concentration. Dielectric response is maximum at x = 0.33 in the series. The results establish a protocol for designing new lead-free relaxor materials based on the co-substitution of Fe3+ and Ta5+ for Ti4+ in SrTiO3. A complex interplay of strain effects arising from distribution of cations at the octahedral sites of the perovskite structure controls the dielectric properties. PMID:27514668

  7. Lead free Ba0.8Ca0.2TexTi1-xO3 ferroelectric ceramics exhibiting high electrocaloric properties

    NASA Astrophysics Data System (ADS)

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

    2017-02-01

    Direct and indirect electrocaloric measurements were performed on the new Tellurium (Te) doped Ba0.8Ca0.2TiO3 (BCT) ceramics. The effects of Te addition on structural, electrical, and electrocaloric properties of BCT ceramics were investigated. The incorporation of the Te element in the BCT induced the decrease of the Curie temperature and the enhancement of the electrocaloric effect. The significant electrocaloric temperature change ΔT = 1.237 K determined by the direct method was obtained at the relatively moderate field of ˜25 kV/cm in Ba0.8Ca0.2Ti(1-x)TexO3 with x = 0.02. The corresponding electrocaloric responsivity ΔT/ΔE = 0.495 × 10-6 K m V-1 is higher than that observed in pure BCT ceramics and is one of the highest reported so far in lead-free ferroelectric materials. The material's coefficient of performance was determined at the phase transition with a maximal value of 14.7.

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

    NASA Astrophysics Data System (ADS)

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

    2009-10-01

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

  9. Structural, dielectric and electrocaloric properties in lead-free Zr-doped Ba0.8Ca0.2TiO3 solid solution

    NASA Astrophysics Data System (ADS)

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

    2016-07-01

    We investigate in the present work the additional data points (x=0.02, 0.06 and 0.08) to the previous reported paper (Asbani et al., 2015) [21] that sufficiently enrich to understand the EC properties and underlying phase diagram of the lead-free Ba0.8Ca0.2Ti(1-x)ZrxO3 (xBCTZ) system. X-ray diffraction analysis performed at room temperature, confirms a continuous tetragonal solid solution with P4mm (No. 99) space group that evolved to pseudo-cubic symmetry for the high Zr-content compounds. Ferroelectric and paraelectric behaviors were highlighted using P-E hysteresis data versus temperature. Phase transition was confirmed by dielectric permittivity measurements versus temperature showing a decrease of the Curie temperature when Zr-content increases. From P-E hysteresis recording the electrocaloric temperature change (ΔT) was calculated that ranged in between 0.12 and 0.27 K and the electrocaloric responsivity (ξ) in 0.15 to 0.34×10-6 K·m/V under 7.95 kV/cm applied electric field. The zero-field entropy is compared to electrocaloric isothermal entropy to estimate the extent the EC is being under-driven.

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

    NASA Astrophysics Data System (ADS)

    Shi, Hongbin; Tian, Cuihua; Ueda, Toshitsugu

    2012-04-01

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

  11. Preparation and dielectric properties of the lead-free BaFe1/2Nb1/2O3 ceramics obtained from mechanically triggered powder

    NASA Astrophysics Data System (ADS)

    Bochenek, Dariusz; Niemiec, Przemysław; Szafraniak-Wiza, Izabela; Adamczyk, Małgorzata; Skulski, Ryszard

    2015-10-01

    In the paper the influence of mechanical activation of the powder on the final dielectric properties lead-free Ba(Fe1/2Nb1/2)O3 (BFN) ceramic was examined. The BFN ceramics were obtained by 3-steps route. Firstly, the substrates were pre-homogenized in a planetary ball mill. Than, the powder was activated in vibratory mill (the shaker type SPEX 8000 Mixer Mill) for different duration between 25 h and 100 h. The influence of the milling time on the BFN powder was monitored by X-ray diffraction. The diffraction data confirmed that the milling process of the starting components is accompanied by partial synthesis of the BFN materials. The longer of the high-energy milling duration the powders results in increasing the amount of amorphous/nanocrystalline content. The mechanically activated materials were sintered in order to obtain the ceramic samples. During this temperature treatment the final crystallisation of the powder appeared what was confirmed by XRD studies. The performed dielectric measurements have revealed the reduction of the dielectric loss of the BFN ceramics compared to materials obtained by classic methods.

  12. Relaxor nature in lead-free Sr{sub 5}LaTi{sub 3}Nb{sub 7}O{sub 30} tetragonal tungsten bronze ceramics

    SciTech Connect

    Li Zhu, Xiao; Li, Kun; Qiang Liu, Xiao; Ming Chen, Xiang; Asif Rafiq, Muhammad

    2013-09-28

    Lead-free tetragonal tungsten bronze Sr{sub 5}LaTi{sub 3}Nb{sub 7}O{sub 30} ceramics were prepared and the correlation of the relaxor nature and crystal structure was studied using dielectric spectroscopy and powder X-ray diffraction. Three dielectric relaxations were observed below the deviation temperature T{sub D}∼ 330 K. Relaxation I and II followed the Vogel-Fulcher law with the freezing temperatures of 189 K and ∼90 K. Low temperature relaxation III, which was first observed in filled tungsten bronze, followed well the Arrhenius law. Dielectric response becomes static below 50 K. Polarization-field (P-E) hysteresis loops were evaluated from 183 K to 298 K. P{sub r} value of 0.41μC/cm{sup 2} was observed at 183 K. Deviation of lattice parameter c from the linear contraction and increasing of tetragonality (c/a ratio) were observed below T{sub D}, reflecting the structure change during the formation of polar nanoregions and the following freezing process. Opposite tendency was observed below 100 K for all the lattice parameters, corresponding to relaxation III. Generally, the main dielectric relaxation I and II were attributed to flipping and breathing of polar nanoregions along c axis, while the concerted rotations of the oxygen octahedra in the ab plane were suggested as the origin of relaxation III.

  13. Derivation of Piezoelectric Losses from Admittance Spectra

    NASA Astrophysics Data System (ADS)

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

    2009-04-01

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

  14. Piezoelectric paint sensor for ultrasonic NDE

    NASA Astrophysics Data System (ADS)

    Li, X.; Zhang, Y.

    2007-04-01

    This paper deals with a distributed acoustic emission sensing method, which is especially suitable for piezoelectric paint. Piezoelectric paint is a composite piezoelectric material that is comprised of tiny piezoelectric particles randomly dispersed within a polymer matrix phase. An overview of the distributed acoustic emission sensing method for defect monitoring is given in this paper. The use of piezoelectric materials for ultrasonic signal measurements is next discussed along with a series of ultrasonic tests performed to verify the ultrasonic sensing capability of piezoelectric paint. To examine the mechanism of the distributed acoustic emission sensing method for crack initiation detection, the results of a finite element simulation based study is presented in this paper. The finite element model used in the parametric study is calibrated with experimental data. The effect of sensor numbers included in the array has been studied using both simulation and experimental data. Based on the preliminary results of this study, piezoelectric paint sensor appears to hold a potential for use in on-line monitoring of cracks such as those caused by fatigue in metal structures although more work is still needed before successful practical application can be made.

  15. The nonlinear piezoelectric tuned vibration absorber

    NASA Astrophysics Data System (ADS)

    Soltani, P.; Kerschen, G.

    2015-07-01

    This paper proposes a piezoelectric vibration absorber, termed the nonlinear piezoelectric tuned vibration absorber (NPTVA), for the mitigation of nonlinear resonances of mechanical systems. The new feature of the NPTVA is that its nonlinear restoring force is designed according to a principle of similarity, i.e., the NPTVA should be an electrical analog of the nonlinear host system. Analytical formulas for the NPTVA parameters are derived using the homotopy perturbation method. Doing so, a nonlinear generalization of Den Hartog’s equal-peak tuning rule is developed for piezoelectric vibration absorbers.

  16. Miniature Piezoelectric Macro-Mass Balance

    NASA Technical Reports Server (NTRS)

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

    2010-01-01

    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

  17. A piezoelectric pseudo-bimorph actuator

    NASA Astrophysics Data System (ADS)

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

    2013-06-01

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

  18. Optimum power and efficiency of piezoelectric vibration energy harvesters with sinusoidal and random vibrations

    NASA Astrophysics Data System (ADS)

    Renaud, M.; Elfrink, R.; Jambunathan, M.; de Nooijer, C.; Wang, Z.; Rovers, M.; Vullers, R.; van Schaijk, R.

    2012-10-01

    Assuming a sinusoidal vibration as input, an inertial piezoelectric harvester designed for maximum efficiency of the electromechanical energy conversion does not always lead to maximum power generation. In this case, what can be gained by optimizing the efficiency of the device? Detailing an answer to this question is the backbone of this paper. It is shown that, while the maximum efficiency operating condition does not always lead to maximum power generation, it corresponds always to maximum power per square unit deflection of the piezoelectric harvester. This understanding allows better optimization of the generated power when the deflection of the device is limited by hard stops. This is illustrated by experimental measurements on vacuum-packaged MEMS harvesters based on AlN as piezoelectric material. The results obtained for a sinusoidal vibration are extended to random vibrations. In this case, we demonstrate that the optimum generated power is directly proportional to the efficiency of the harvester, thus answering the initial question. For both types of studied vibrations, simple closed-form formulas describing the generated power and efficiency in optimum operating conditions are elaborated. These formulas are based on parameters that are easily measured or modeled. Therefore, they are useful performance metrics for existing piezoelectric harvesters.

  19. Identification of piezoelectric complex parameters in rings for power ultrasound applications

    NASA Astrophysics Data System (ADS)

    Pérez, N.; Andrade, M. A.; Carbonari, R. C.; Buiochi, F.; Adamowski, J. C.

    2012-12-01

    Power ultrasonic devices frequently use Langevin type transducers. These types of transducers are essentially constructed using a sandwich of piezoelectric rings and two metal masses at the ends. The whole assembly is tuned to resonate in a desired main frequency and the total length corresponds to a half of the wavelength of that frequency. Finite element simulations (FEM) are used in the design of such complex structures; however the accuracy of the results is limited by the knowledge of the constitutive properties for the materials used in the transducer construction. Metals like aluminum or steel are well characterized, but the complete set of piezoelectric parameters for piezoceramics are difficult to find in the literature. In the few cases where the manufacturer gives the complete set of parameters, strong differences are observed between simulated and experimental data. In this work a novel methodology proposed by our research group is applied in the case of piezoelectric rings made with a hard piezoelectric material. The results are evaluated in rings with internal diameter 8 mm, external diameter 27 mm and thickness 5 mm. Finally the results are validated using an optical interferometer showing a good agreement.

  20. Piezoelectric and Semiconducting Coupled Nanogenerators

    NASA Technical Reports Server (NTRS)

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

    2012-01-01

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

  1. Computational homogenization of fibrous piezoelectric materials

    NASA Astrophysics Data System (ADS)

    Maruccio, Claudio; De Lorenzis, Laura; Persano, Luana; Pisignano, Dario

    2015-05-01

    Flexible piezoelectric devices made of polymeric materials are widely used for micro- and nano-electro-mechanical systems. In particular, numerous recent applications concern energy harvesting. Due to the importance of computational modeling to understand the influence that microscale geometry and constitutive variables exert on the macroscopic behavior, a numerical approach is developed here for multiscale and multiphysics modeling of thin piezoelectric sheets made of aligned arrays of polymeric nanofibers, manufactured by electrospinning. At the microscale, the representative volume element consists in piezoelectric polymeric nanofibers, assumed to feature a piezoelastic behavior and subjected to electromechanical contact constraints. The latter are incorporated into the virtual work equations by formulating suitable electric, mechanical and coupling potentials and the constraints are enforced by using the penalty method. From the solution of the micro-scale boundary value problem, a suitable scale transition procedure leads to identifying the performance of a macroscopic thin piezoelectric shell element.

  2. Polarization Stability of Amorphous Piezoelectric Polyimides

    NASA Technical Reports Server (NTRS)

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

    2000-01-01

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

  3. Piezoelectric nanoparticle-polymer composite foams.

    PubMed

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

    2014-11-26

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

  4. Thermally Stable Piezoelectric and Pyroelectric Polymers

    NASA Technical Reports Server (NTRS)

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

    2006-01-01

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

  5. Piezoelectric devices for generating low power

    NASA Astrophysics Data System (ADS)

    Chilibon, Irinela

    2016-12-01

    This paper reviews concepts and applications in low-power electronics and energy harvesting technologies. Various piezoelectric materials and devices for small power generators useful in renewable electricity are presented. The vibrating piezoelectric device differs from the typical electrical power source in that it has capacitive rather than inductive source impedance, and may be driven by mechanical vibrations of varying amplitude. In general, vibration energy could be converted into electrical energy using one of three techniques: electrostatic charge, magnetic fields and piezoelectric. A low power piezoelectric generator, having a PZT element was realised in order to supply small electronic elements, such as optoelectronic small devices, LEDs, electronic watches, small sensors, interferometry with lasers or Micro-electro-mechanical System (MEMS) array with multi-cantilevers.

  6. Simulation of Piezoelectric Jellyfish Power Generator

    NASA Astrophysics Data System (ADS)

    Wu, Yeong-Jen; Lai, Wei-Hsiang

    The energy problem is getting increasingly serious. As such, unused energy recovery technology is crucial for environmental protection, which has been investigated extensively. Several methods have been developed to utilize scavenged energy from the environment, such as waste heat, solar energy, wind energy, and tides energy to convert into useful power. There is a new idea of piezoelectric jellyfish generator which combines the utilization of sea wave and vibration energy. When sea wave passes through the jellyfish, the wave causes the tentacles to vibrate. The tentacles is made of piezoelectric polymer which can convert the strain energy into electrical energy. This paper discusses about the piezoelectric jellyfish's tentacles being disturbed by wave in the sea. We employed the commercial CFD software CFD-ACE+ 2006 to simulate this phenomenon. The parameters including its tentacle length (L) and wave propagating function (Y) are studied which affect the piezoelectric jellyfish capacity to generate power.

  7. Studying insect motion with piezoelectric sensors

    NASA Astrophysics Data System (ADS)

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

    2007-04-01

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

  8. Rapid Solidification of Sn-Cu-Al Alloys for High-Reliability, Lead-Free Solder: Part II. Intermetallic Coarsening Behavior of Rapidly Solidified Solders After Multiple Reflows

    NASA Astrophysics Data System (ADS)

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

    2016-12-01

    Controlling the size, dispersion, and stability of intermetallic compounds in lead-free solder alloys is vital to creating reliable solder joints regardless of how many times the solder joints are melted and resolidified (reflowed) during circuit board assembly. In this article, the coarsening behavior of Cu x Al y and Cu6Sn5 in two Sn-Cu-Al alloys, a Sn-2.59Cu-0.43Al at. pct alloy produced via drip atomization and a Sn-5.39Cu-1.69Al at. pct alloy produced via melt spinning at a 5-m/s wheel speed, was characterized after multiple (1-5) reflow cycles via differential scanning calorimetry between the temperatures of 293 K and 523 K (20 °C and 250 °C). Little-to-no coarsening of the Cu x Al y particles was observed for either composition; however, clustering of Cu x Al y particles was observed. For Cu6Sn5 particle growth, a bimodal size distribution was observed for the drip atomized alloy, with large, faceted growth of Cu6Sn5 observed, while in the melt spun alloy, Cu6Sn5 particles displayed no significant increase in the average particle size, with irregularly shaped, nonfaceted Cu6Sn5 particles observed after reflow, which is consistent with shapes observed in the as-solidified alloys. The link between original alloy composition, reflow undercooling, and subsequent intermetallic coarsening behavior was discussed by using calculated solidification paths. The reflowed microstructures suggested that the heteroepitaxial relationship previously observed between the Cu x Al y and the Cu6Sn5 was maintained for both alloys.

  9. Controlling Interfacial Reactions and Intermetallic Compound Growth at the Interface of a Lead-free Solder Joint with Layer-by-Layer Transferred Graphene.

    PubMed

    Ko, Yong-Ho; Lee, Jong-Dae; Yoon, Taeshik; Lee, Chang-Woo; Kim, Taek-Soo

    2016-03-02

    The immoderate growth of intermetallic compounds (IMCs) formed at the interface of a solder metal and the substrate during soldering can degrade the mechanical properties and reliability of a solder joint in electronic packaging. Therefore, it is critical to control IMC growth at the solder joints between the solder and the substrate. In this study, we investigated the control of interfacial reactions and IMC growth by the layer-by-layer transfer of graphene during the reflow process at the interface between Sn-3.0Ag-0.5Cu (in wt %) lead-free solder and Cu. As the number of graphene layers transferred onto the surface of the Cu substrate increased, the thickness of the total IMC (Cu6Sn5 and Cu3Sn) layer decreased. After 10 repetitions of the reflow process for 50 s above 217 °C, the melting temperature of Sn-3.0Ag-0.5Cu, with a peak temperature of 250 °C, the increase in thickness of the total IMC layer at the interface with multiple layers of graphene was decreased by more than 20% compared to that at the interface of bare Cu without graphene. Furthermore, the average diameter of the Cu6Sn5 scallops at the interface with multiple layers of graphene was smaller than that at the interface without graphene. Despite 10 repetitions of the reflow process, the growth of Cu3Sn at the interface with multiple layers of graphene was suppressed by more than 20% compared with that at the interface without graphene. The multiple layers of graphene at the interface between the solder metal and the Cu substrate hindered the diffusion of Cu atoms from the Cu substrate and suppressed the reactions between Cu and Sn in the solder. Thus, the multiple layers of graphene transferred at the interface between dissimilar metals can control the interfacial reaction and IMC growth occurring at the joining interface.

  10. A nanoscale piezoelectric transformer for low-voltage transistors.

    PubMed

    Agarwal, Sapan; Yablonovitch, Eli

    2014-11-12

    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.

  11. Improved Multiple-DOF SAW Piezoelectric Motors

    NASA Technical Reports Server (NTRS)

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

    2003-01-01

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

  12. Distributed structural control using multilayered piezoelectric actuators

    NASA Technical Reports Server (NTRS)

    Cudney, Harley H.; Inman, Daniel J.; Oshman, Yaakov

    1990-01-01

    A method of segmenting piezoelectric sensors and actuators is proposed which can preclude the currently experienced cancelation of sensor signals, or the reduction of actuator effectiveness, due to the integration of the property undergoing measurement or control. The segmentation method is demonstrated by a model developed for beam structures, to which multiple layers of piezoelectric materials are attached. A numerical study is undertaken of increasing active and passive damping of a beam using the segmented sensors and actuators over unsegmented sensors and actuators.

  13. Half-Heusler semiconductors as piezoelectrics.

    PubMed

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

    2012-07-20

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

  14. Piezoelectric Polymer Tactile Sensor Arrays for Robotics.

    DTIC Science & Technology

    1987-12-01

    machine and positioning the HRP master to be copied in the master position. The emulsion surface of the HRP master faced outward. The master vacuum ...machine. The HRP was centered before the copy vacuum button was pressed to secure the HRP. The emulsion surfaces of the HRP’s came into contact when the...Compared to Experiment for the Piezoelectric Constant e’. .................... 2.32 2.5 Calculated Fractional Contributions for the Piezoelectric Constant

  15. In situ health monitoring of piezoelectric sensors

    NASA Technical Reports Server (NTRS)

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

    2013-01-01

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

  16. Ordering of hard particles between hard walls

    NASA Astrophysics Data System (ADS)

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

    2001-05-01

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

  17. Dielectric loss against piezoelectric power harvesting

    NASA Astrophysics Data System (ADS)

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

    2014-09-01

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

  18. Hardness Tester for Polyur

    NASA Technical Reports Server (NTRS)

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

    1987-01-01

    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.

  19. Session: Hard Rock Penetration

    SciTech Connect

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

    1992-01-01

    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.

  20. Piezoelectric microcantilever serum protein detector

    NASA Astrophysics Data System (ADS)

    Capobianco, Joseph A.

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

  1. Model of a Piezoelectric Transducer

    NASA Technical Reports Server (NTRS)

    Goodenow, Debra

    2004-01-01

    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

  2. Electric field induced short range to long range structural ordering and its influence on the Eu{sup +3} photoluminescence in the lead-free ferroelectric Na{sub 1/2}Bi{sub 1/2}TiO{sub 3}

    SciTech Connect

    Kalaskar, Abhijeet; Rao, Badari Narayana; Ranjan, Rajeev; Thomas, Tiju

    2015-06-28

    Eu{sup +3} was incorporated into the lattice of a lead-free ferroelectric Na{sub 1/2}Bi{sub 1/2}TiO{sub 3} (NBT) as per the nominal formula Na{sub 0.5}Bi{sub 0.5−x}Eu{sub x}TiO{sub 3}. This system was investigated with regard to the Eu{sup +3} photoluminescence (PL) and structural behaviour as a function of composition and electric field. Electric field was found to irreversibly change the features in the PL spectra and also in the x-ray diffraction patterns below the critical composition x = 0.025. Detailed analysis revealed that below the critical composition, electric field irreversibly suppresses the structural heterogeneity inherent of the host matrix NBT and brings about a long range ferroelectric state with rhombohedral (R3c) distortion. It is shown that the structural disorder on the nano-scale opens a new channel for radiative transition which manifests as a new emission line branching off from the main {sup 5}D{sub 0}→{sup 7}F{sub 0} line along with a concomitant change in the relative intensity of the other crystal field induced Stark lines with different J values. The study suggests that Eu{sup +3} luminescence can be used to probe the relative degree of field induced structural ordering in relaxor ferroelectrics and also in high performance piezoelectric alloys where electric field couples very strongly with the lattice and structural degrees of freedom.

  3. Continuous cross-over from ferroelectric to relaxor state and piezoelectric properties of BaTiO{sub 3}-BaZrO{sub 3}-CaTiO{sub 3} single crystals

    SciTech Connect

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

    2014-04-14

    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 (Ba{sub 0.850}Ca{sub 0.150})(Ti{sub 0.900}Zr{sub 0.100})O{sub 3} ceramics exhibit outstanding piezoelectric coefficients. For the first time, we report the growth of piezoelectric lead-free single crystals in the BaTiO{sub 3}-BaZrO{sub 3}-CaTiO{sub 3} pseudo-ternary system. The stoichiometry control in the CaO-BaO-TiO{sub 2}-ZrO{sub 2} solid solution led to single crystals with various compositions ranging from (Ba{sub 0.857}Ca{sub 0.143})(Ti{sub 0.928}Zr{sub 0.072})O{sub 3} to (Ba{sub 0.953}Ca{sub 0.047})(Ti{sub 0.427}Zr{sub 0.573})O{sub 3}. 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 (Ba{sub 0.838}Ca{sub 0.162})(Ti{sub 0.854}Zr{sub 0.146})O{sub 3} composition, which has been grown and oriented along [001] crystallographic direction, displayed electromechanical coefficients d{sub 31} and k{sub 31} of 93 pC.N{sup −1} and 0.18, respectively, near the room temperature (T = 305 K)

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

    NASA Astrophysics Data System (ADS)

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

    2014-04-01

    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).

  5. Analysis of nonlinear transient responses of piezoelectric resonators.

    PubMed

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

    2011-09-01

    The electric transient response method is an effective technique to evaluate material constants of piezoelectric ceramics under high-power driving. In this study, we tried to incorporate nonlinear piezoelectric behaviors in the analysis of transient responses. As a base for handling the nonlinear piezoelectric responses, we proposed an assumption that the electric displacement is proportional to the strain without phase lag, which could be described by a real and constant piezoelectric e-coefficient. Piezoelectric constitutive equations including nonlinear responses were proposed to calculate transient responses of a piezoelectric resonator. The envelopes and waveforms of current and vibration velocity in transient responses observed in some piezoelectric ceramics could be fitted with the calculation including nonlinear responses. The procedure for calculation of mechanical quality factor Q(m) for piezoelectric resonators with nonlinear behaviors was also proposed.

  6. Narcotics detection using piezoelectric ringing

    NASA Astrophysics Data System (ADS)

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

    1997-02-01

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

  7. Multilayer Piezoelectric Stack Actuator Characterization

    NASA Technical Reports Server (NTRS)

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

    2008-01-01

    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.

  8. Piezoelectric tunable microwave superconducting cavity

    NASA Astrophysics Data System (ADS)

    Carvalho, N. C.; Fan, Y.; Tobar, M. E.

    2016-09-01

    In the context of engineered quantum systems, there is a demand for superconducting tunable devices, able to operate with high-quality factors at power levels equivalent to only a few photons. In this work, we developed a 3D microwave re-entrant cavity with such characteristics ready to provide a very fine-tuning of a high-Q resonant mode over a large dynamic range. This system has an electronic tuning mechanism based on a mechanically amplified piezoelectric actuator, which controls the resonator dominant mode frequency by changing the cavity narrow gap by very small displacements. Experiments were conducted at room and dilution refrigerator temperatures showing a large dynamic range up to 4 GHz and 1 GHz, respectively, and were compared to a finite element method model simulated data. At elevated microwave power input, nonlinear thermal effects were observed to destroy the superconductivity of the cavity due to the large electric fields generated in the small gap of the re-entrant cavity.

  9. Multilayer piezoelectric stack actuator characterization

    NASA Astrophysics Data System (ADS)

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

    2008-03-01

    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 -180°C to +200°C 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.

  10. Dynamic hardness of metals

    NASA Astrophysics Data System (ADS)

    Liang, Xuecheng

    Dynamic hardness (Pd) of 22 different pure metals and alloys having a wide range of elastic modulus, static hardness, and crystal structure were measured in a gas pulse system. The indentation contact diameter with an indenting sphere and the radius (r2) of curvature of the indentation were determined by the curve fitting of the indentation profile data. r 2 measured by the profilometer was compared with that calculated from Hertz equation in both dynamic and static conditions. The results indicated that the curvature change due to elastic recovery after unloading is approximately proportional to the parameters predicted by Hertz equation. However, r 2 is less than the radius of indenting sphere in many cases which is contradictory to Hertz analysis. This discrepancy is believed due to the difference between Hertzian and actual stress distributions underneath the indentation. Factors which influence indentation elastic recovery were also discussed. It was found that Tabor dynamic hardness formula always gives a lower value than that directly from dynamic hardness definition DeltaE/V because of errors mainly from Tabor's rebound equation and the assumption that dynamic hardness at the beginning of rebound process (Pr) is equal to kinetic energy change of an impact sphere over the formed crater volume (Pd) in the derivation process for Tabor's dynamic hardness formula. Experimental results also suggested that dynamic to static hardness ratio of a material is primarily determined by its crystal structure and static hardness. The effects of strain rate and temperature rise on this ratio were discussed. A vacuum rotating arm apparatus was built to measure Pd at 70, 127, and 381 mum sphere sizes, these results exhibited that Pd is highly depended on the sphere size due to the strain rate effects. P d was also used to substitute for static hardness to correlate with abrasion and erosion resistance of metals and alloys. The particle size effects observed in erosion were

  11. Energy Harvesting From Low Frequency Applications Using Piezoelectric Materials

    SciTech Connect

    Li, Huidong; Tian, Chuan; Deng, Zhiqun

    2014-11-06

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

  12. Piezoelectric biosensor with a ladder polymer substrate coating

    DOEpatents

    Renschler, Clifford L.; White, Christine A.; Carter, Robert M.

    1998-01-01

    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.

  13. Direct Piezoelectricity of Soft Composite Electrospun Fibers

    NASA Astrophysics Data System (ADS)

    Varga, Michael; Morvan, Jason; Diorio, Nick; Buyuktanir, Ebru; Harden, John; West, John; Jakli, Antal

    2013-03-01

    Recently soft fiber mats electrospun from solutions of Barium Titanate (BT) ferroelectric ceramics particles and poly lactic acid (PLA) were found to have large (d33 1nm/V) converse piezoelectric signals offering a myriad of applications ranging from active implants to smart textiles. Here we report direct piezoelectric measurements (electric signals due to mechanical stress) of the BT/PLA composite fiber mats at various BT concentrations. A testing apparatus was designed and constructed solely for these measurements involving AC stresses provided by a speaker in 10Hz-10kHz frequency range. The piezoelectric constant d33 ~1nC/N was found to be in agreement with the prior converse piezoelectric measurements. The largest signals were obtained with 6% BT/PLA composites, probably because the BT particles at higher concentrations could not be dispersed homogeneously. Importantly the direct piezoelectric signal is large enough to power a small LCD by simply pressing a 0.2mm thick 2 cm2 area mat by a finger. We expect to use these mats in active Braille cells and in liquid crystal writing tablets.

  14. Contact mechanics of piezoelectric ultrasonic motors

    NASA Astrophysics Data System (ADS)

    Wallaschek, Jörg

    1998-06-01

    Piezoelectric ultrasonic motors are driven by tangential stresses in the interface between stator and rotor. These stresses are generated by the elliptical motion of the material points of the stator or rotor surface and depend on frictional processes in the contact area. The contact mechanics of piezoelectric ultrasonic motors determines the operational characteristics, like rotational speed and torque or transmitted mechanical power and efficiency. Wear properties and lifetime of piezoelectric ultrasonic motors are also determined by contact mechanics. The goal of the present paper is to summarize the state of the art in the understanding of some fundamental processes governing the contact mechanics of piezoelectric ultrasonic motors. After a short introduction, a survey of publications devoted to the subject will be given. Then, an attempt will be made to classify the mechanical models, which were developed in order to explain the contact mechanics of piezoelectric ultrasonic motors, according to the physical effects which have been taken into account in their derivation. Some results concerning the choice of proper contact materials, wear and lifetime of ultrasonic motors will be addressed in a separate section. Finally a summary and outlook will be given and open questions for future research will be formulated.

  15. High-Fidelity Piezoelectric Audio Device

    NASA Technical Reports Server (NTRS)

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

    2003-01-01

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

  16. Optical piezoelectric transducer for nano-ultrasonics.

    PubMed

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

    2005-08-01

    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 detection of the propagating NAW. Based on these piezoelectric-based optical principles, we have designed an optical piezoelectric transducer (OPT) to generate NAW. The optically generated NAW is then applied to one-dimensional (1-D) ultrasonic scan for thickness measurement, which is the first step toward multidimensional nano-ultrasonic imaging. By launching a NAW pulse and resolving the returned acoustic echo signal with femtosecond optical pulses, the thickness of the studied layer can be measured with <1 nm resolution. This nano-structured OPT technique will provide the key toward the realization of nano-ultrasonics, which is analogous to the typical ultrasonic techniques but in a nanometer scale.

  17. Characterization of a Piezoelectric Buzzer Using a Michelson Interferometer

    ERIC Educational Resources Information Center

    Lloyd, S.; Paetkau, M.

    2010-01-01

    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…

  18. Piezoelectric Properties of Non-Polar Block Copolymers

    SciTech Connect

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

    2011-01-01

    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.

  19. Low-power piezoelectric micro-machined valve

    NASA Technical Reports Server (NTRS)

    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

    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.

  20. Organizing Your Hard Disk.

    ERIC Educational Resources Information Center

    Stocker, H. Robert; Hilton, Thomas S. E.

    1991-01-01

    Suggests strategies that make hard disk organization easy and efficient, such as making, changing, and removing directories; grouping files by subject; naming files effectively; backing up efficiently; and using PATH. (JOW)

  1. Radiation from hard objects

    SciTech Connect

    Canavan, G.H.

    1997-02-01

    The inference of the diameter of hard objects is insensitive to radiation efficiency. Deductions of radiation efficiency from observations are very sensitive - possibly overly so. Inferences of the initial velocity and trajectory vary similarly, and hence are comparably sensitive.

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

    SciTech Connect

    Stoeckel, C. Kaufmann, C.; Hahn, R.; Schulze, R.; Billep, D.; Gessner, T.

    2014-07-21

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

  3. Giant piezoelectricity of monolayer group IV monochalcogenides

    NASA Astrophysics Data System (ADS)

    Fei, Ruixiang; Li, Wenbin; Li, Ju; Yang, Li

    We predict enormous, anisotropic piezoelectric effects in intrinsic monolayer group IV monochalcogenides (MX, M =Sn or Ge, X =Se or S), including SnSe, SnS, GeSe, and GeS. Using first-principle simulations based on the modern theory of polarization, we find that their piezoelectric coefficients are about one to two orders of magnitude larger than those of other 2D materials, such as MoS2 and GaSe, and bulk quartz and AlN which are widely used in industry. This enhancement is a result of the unique ``puckered'' C2v symmetry and electronic structure of monolayer group IV monochalcogenides. Given the achieved experimental advances in the fabrication of monolayers, their flexible character, and ability to withstand enormous strain, these 2D structures with giant piezoelectric effects may be promising for a broad range of applications such as nano-sized sensors, piezotronics, and energy harvesting in portable electronic devices.

  4. Green piezoelectric for autonomous smart textile

    NASA Astrophysics Data System (ADS)

    Lemaire, E.; Borsa, C. J.; Briand, D.

    2015-12-01

    In this work, the fabrication of Rochelle salt based piezoelectric textiles are shown. Structures composed of fibers and Rochelle salt are easily produced using green processes. Both manufacturing and the material itself are really efficient in terms of environmental impact, considering the fabrication processes and the material resources involved. Additionally Rochelle salt is biocompatible. In this green paradigm, active sensing or actuating textiles are developed. Thus processing method and piezoelectric properties have been studied: (1) pure crystals are used as acoustic actuator, (2) fabrication of the textile-based composite is detailed, (3) converse effective d33 is evaluated and compared to lead zirconate titanate ceramic. The utility of textile-based piezoelectric merits its use in a wide array of applications.

  5. Piezoelectric energy harvesting computer controlled test bench

    NASA Astrophysics Data System (ADS)

    Vázquez-Rodriguez, M.; Jiménez, F. J.; de Frutos, J.; Alonso, D.

    2016-09-01

    In this paper a new computer controlled (C.C.) laboratory test bench is presented. The patented test bench is made up of a C.C. road traffic simulator, C.C. electronic hardware involved in automating measurements, and test bench control software interface programmed in LabVIEW™. Our research is focused on characterizing electronic energy harvesting piezoelectric-based elements in road traffic environments to extract (or "harvest") maximum power. In mechanical to electrical energy conversion, mechanical impacts or vibrational behavior are commonly used, and several major problems need to be solved to perform optimal harvesting systems including, but no limited to, primary energy source modeling, energy conversion, and energy storage. It is described a novel C.C. test bench that obtains, in an accurate and automatized process, a generalized linear equivalent electrical model of piezoelectric elements and piezoelectric based energy store harvesting circuits in order to scale energy generation with multiple devices integrated in different topologies.

  6. Ciliae-based actuator with piezoelectric excitation

    NASA Astrophysics Data System (ADS)

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

    2012-06-01

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

  7. Piezoelectric energy harvesting computer controlled test bench.

    PubMed

    Vázquez-Rodriguez, M; Jiménez, F J; de Frutos, J; Alonso, D

    2016-09-01

    In this paper a new computer controlled (C.C.) laboratory test bench is presented. The patented test bench is made up of a C.C. road traffic simulator, C.C. electronic hardware involved in automating measurements, and test bench control software interface programmed in LabVIEW™. Our research is focused on characterizing electronic energy harvesting piezoelectric-based elements in road traffic environments to extract (or "harvest") maximum power. In mechanical to electrical energy conversion, mechanical impacts or vibrational behavior are commonly used, and several major problems need to be solved to perform optimal harvesting systems including, but no limited to, primary energy source modeling, energy conversion, and energy storage. It is described a novel C.C. test bench that obtains, in an accurate and automatized process, a generalized linear equivalent electrical model of piezoelectric elements and piezoelectric based energy store harvesting circuits in order to scale energy generation with multiple devices integrated in different topologies.

  8. Flow Energy Piezoelectric Bimorph Nozzle Harvester

    NASA Technical Reports Server (NTRS)

    Sherrit, Stewart (Inventor); Walkemeyer, Phillip E. (Inventor); Hall, Jeffrey L. (Inventor); Lee, Hyeong Jae (Inventor); Colonius, Tim (Inventor); Tosi, Phillipe (Inventor); Kim, Namhyo (Inventor); Sun, Kai (Inventor); Corbett, Thomas Gary (Inventor); Arrazola, Alvaro Jose (Inventor)

    2016-01-01

    A flow energy harvesting device having a harvester pipe includes a flow inlet that receives flow from a primary pipe, a flow outlet that returns the flow into the primary pipe, and a flow diverter within the harvester pipe having an inlet section coupled to the flow inlet, a flow constriction section coupled to the inlet section and positioned at a midpoint of the harvester pipe and having a spline shape with a substantially reduced flow opening size at a constriction point along the spline shape, and an outlet section coupled to the constriction section. The harvester pipe may further include a piezoelectric structure extending from the inlet section through the constriction section and point such that the fluid flow past the constriction point results in oscillatory pressure amplitude inducing vibrations in the piezoelectric structure sufficient to cause a direct piezoelectric effect and to generate electrical power for harvesting.

  9. Charge Capacity of Piezoelectric Membrane Wings

    NASA Astrophysics Data System (ADS)

    Grybas, Matthew; Hubner, J. Paul

    2015-11-01

    Micro air vehicles (MAVs) have small wings often fabricated with flexible frames and membranes. These membranes flex and vibrate. Piezoelectric films have the ability to convert induced stress or strain into electrical energy. Thus, it is of interest to investigate if piezoelectric films can be used as a structural member of an MAV wing and generate both lift and energy through passive vibrations. Both a shaker test and a wind tunnel test have been conducted to characterize and assess energy production and aerodynamic characteristics including lift, drag and efficiency. The piezoelectric film has been successful as a lifting surface and produces a measurable charge. This work was supported by NSF REU Site Award 1358991.

  10. Design considerations for piezoelectric polymer ultrasound transducers.

    PubMed

    Brown, L F

    2000-01-01

    Much work has been published on the design of ultrasound transducers using piezoelectric ceramics, but a great deal of this work does not apply when using the piezoelectric polymers because of their unique electrical and mechanical properties. The purpose of this paper is to review and present new insight into seven important considerations for the design of active piezoelectric polymer ultrasound transducers: piezoelectric polymer materials selection, transducer construction and packaging requirements, materials characterization and modeling, film thickness and active area design, electroding selection, backing material design, and front protection/matching layer design. Besides reviewing these design considerations, this paper also presents new insight into the design of active piezoelectric polymer ultrasonic transducers. The design and fabrication of an immersible ultrasonic transducer, which has no adhesive layer between the active element and backing layer, is included. The transducer features direct deposition of poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] copolymer onto an insulated aluminum backing substrate. Pulse-echo tests indicated a minimum insertion loss of 37 dB and -6 dB bandwidth of 9.8 to 22 MHz (71%). The use of polymer wear-protection/quarter-wave matching layers is also discussed. Test results on a P(VDF-TrFE) transducer showed that a Mylar/sup TM/ front layer provided a slight increase in pulse-echo amplitude of 15% (or 1.2 dB) and an increase in -6 dB pulse-echo fractional bandwidth from 86 to 95%. Theoretical derivations are reported for optimizing the active area of the piezoelectric polymer element for maximum power transfer at resonance. These derivations are extended to the special case for a low profile (i.e., thin) shielded transducer. A method for modeling the non-linear loading effects of a commercial pulser-receiver is also included.

  11. Radial-Electric-Field Piezoelectric Diaphragm Pumps

    NASA Technical Reports Server (NTRS)

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

    2009-01-01

    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.

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

    SciTech Connect

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

    2014-12-28

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

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

    PubMed

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

    2014-12-28

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

  14. Reducing the capacitance of piezoelectric film sensors.

    PubMed

    González, Martín G; Sorichetti, Patricio A; Santiago, Guillermo D

    2016-04-01

    We present a novel design for large area, wideband, polymer piezoelectric sensor with low capacitance. The large area allows better spatial resolution in applications such as photoacoustic tomography and the reduced capacitance eases the design of fast transimpedance amplifiers. The metalized piezoelectric polymer thin film is segmented into N sections, electrically connected in series. In this way, the total capacitance is reduced by a factor 1/N(2), whereas the mechanical response and the active area of the sensor are not modified. We show the construction details for a two-section sensor, together with the impedance spectroscopy and impulse response experimental results that validate the design.

  15. Telescoping cylindrical piezoelectric fiber composite actuator assemblies

    NASA Technical Reports Server (NTRS)

    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

    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.

  16. Surface-Acoustic-Wave Piezoelectric Microbalance

    NASA Technical Reports Server (NTRS)

    Chuan, Raymond L.; Bowers, William D.

    1992-01-01

    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.

  17. Optimal piezoelectric switching technique for vibration damping

    NASA Astrophysics Data System (ADS)

    Neubauer, Marcus; Oleskiewicz, Robert

    2007-04-01

    This paper describes piezoelectric switching techniques for vibration damping. The dynamical behaviour of a piezoceramics connected to a switching LR shunt and the dissipated energy are obtained using a fundamental piezoelectric model. All calculations are performed in a normalized way and highlight the influence of the electromechanical coupling coefficient of the piezoceramics and the shunt parameters. For the first time, a precise result for the dynamics of a shunted piezoceramics is derived. The analytic results are used to determine the optimal switching sequence and external branch parameters in order to maximize the damping performance. The results are validated by measurements of a clamped beam.

  18. Constitutive Modeling of Piezoelectric Polymer Composites

    NASA Technical Reports Server (NTRS)

    Odegard, Gregory M.; Gates, Tom (Technical Monitor)

    2003-01-01

    A new modeling approach is proposed for predicting the bulk electromechanical properties of piezoelectric composites. The proposed model offers the same level of convenience as the well-known Mori-Tanaka method. In addition, it is shown to yield predicted properties that are, in most cases, more accurate or equally as accurate as the Mori-Tanaka scheme. In particular, the proposed method is used to determine the electromechanical properties of four piezoelectric polymer composite materials as a function of inclusion volume fraction. The predicted properties are compared to those calculated using the Mori-Tanaka and finite element methods.

  19. Piezoelectric and electrostrictive materials for transducer applications

    NASA Astrophysics Data System (ADS)

    Cross, L. E.; Newnham, R. E.; Barsch, G. R.; Biggers, J. V.

    1984-05-01

    A wide range of materials and devices were covered, including composite materials for transducer applications, electrostriction, and conventional piezoelectrics. In piezoelectric composites, progress was made in 3:1 and 3:2 perforated PZT polymer composites, and in transverse reinforced composites. Finite element calculations of stress distributions in 1:3 PZT polymer composites were carried out. Fresnoite glass ceramics have exhibited extreme stability to hydrostatic pressure, and high sensitivity. A new water quenching technique was used to develop PbTiO3, and a detailed analysis of resonant modes of 1:3 PZT epoxy composites was carried out.

  20. Thermal model for piezoelectric transducers (L).

    PubMed

    Butler, John L; Butler, Alexander L; Butler, Stephen C

    2012-10-01

    A lumped parameter equivalent circuit basis for calculating and allocating heat power sources in a transducer is presented along with experimental results. The simple model allows heat power calculations at resonance based on readily attainable parameters for transducers with uniform fields. Measured and finite element analysis of steady state thermal results are compared for the monopole mode of the single crystal driven modal transducer projector. The model serves as a physical and computational aid in the evaluation of piezoelectric transducer heating and may be used for evaluating highly coupled single crystal as well as ceramic piezoelectric transducers.

  1. Characterization of Piezoelectric PDMS-Nanoparticle Composites

    NASA Astrophysics Data System (ADS)

    Borsa, C. J.; Mionic Ebersold, M.; Bowen, P.; Farine, P.-A.; Briand, D.

    2015-12-01

    In this work, the novel fabrication and characterization of elastomeric piezoelectric nanocomposites are explored. Fabrication methods explored herein utilize ball milled barium titanate powder dispersions, along with double walled carbon nanotubes which are dispersed in toluene though the use of an ultrasonic probe. Test devices are then constructed with electrodes made from evaporated gold on polyimide foils and protective dielectrics of pristine PDMS. Two different device construction methods are explored utilizing both direct contact bonding and plasma bonding of the active composite layers to the dielectric/electrode. Test samples are evaluated through the use of a dedicated Berlincourt type piezoelectric d33 meter.

  2. Synthesis and Properties of [Bi0.5(Na1-xAgx)0.5]1-yBayTiO3 Piezoelectric Ceramics

    NASA Astrophysics Data System (ADS)

    Wu, Lang; Xiao, Ding-Quan; Lin, Dun-Min; Zhu, Jian-Guo; Yu, Ping

    2005-12-01

    A new group of ABO3-type lead-free piezoelectric ceramics, [Bi0.5(Na1-xAgx)0.5]1-yBayTiO3, was developed, and the corresponding invention patent was submitted. The ceramics were synthesized by the conventional ceramic sintering technique using electronic grade raw materials, and the preparation techniques are very stable and convenient. The crystalline phase, microstructure and electric properties of the ceramics were also investigated. All the ceramics have high densities of about 5.70-5.84 g/cm3, which are more than 95% of the theoretical values. This system provides high piezoelectric performances: d33=168 pC/N, kp=0.31 when x=0.06, y=0.06. Moreover, the samples doped with a moderate amount of Mn could increase the mechanical quality factor Qm and reduce the dielectric loss \\mathop{tg}δ simultaneously. The temperature dependence of piezoelectric properties measured show that at up to 180°C, d33 can still remain 126 pC/N for [Bi0.5(Na0.96Ag0.04)0.5]0.90Ba0.10TiO3 ceramics, which has a d33 of 137 pC/N at room temperature.

  3. The development of piezoelectric crystal gyroscopes in China

    NASA Astrophysics Data System (ADS)

    Chen, Feng-Yu; Qing, Rong-Kang

    The operation principles and basic characteristics of a newly-developed vibrating-beam piezoelectric crystal angular rate gyroscope are discussed along with the gyroscope applications. Several applications of piezoelectric gyroscopes are described, including its use as a telemetering sensor, attidude measuring device in automobiles, in geological exploraton drilling, and as a sensing element in ship and aircraft control systems. Specifications are presented for several gyroscopes, including those for two piezoelectric angular rate gyros with different applications (telemetering and control), a typical piezoelectric angular displacement gyro, and a piezoelectric inclinometer.

  4. Nanogenerator comprising piezoelectric semiconducting nanostructures and Schottky conductive contacts

    NASA Technical Reports Server (NTRS)

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

    2011-01-01

    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.

  5. 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

    Abrego, Zuriñe; Grijalba, Nagore; Unceta, Nora; Maguregui, Maite; Sanchez, Alicia; Fernández-Isla, Alberto; Goicolea, M Aranzazu; Barrio, Ramón J

    2014-12-07

    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.

  6. Numerical simulation of piezoelectric effect of bone under ultrasound irradiation

    NASA Astrophysics Data System (ADS)

    Hosokawa, Atsushi

    2015-07-01

    The piezoelectric effect of bone under ultrasound irradiation was numerically simulated using an elastic finite-difference time-domain method with piezoelectric constitutive equations (PE-FDTD method). First, to demonstrate the validity of the PE-FDTD method, the ultrasound propagation in piezoelectric ceramics was simulated and then compared with the experimental results. The simulated and experimental waveforms propagating through the ceramics were in good agreement. Next, the piezoelectric effect of human cortical bone on the ultrasound propagation was investigated by PE-FDTD simulation. The simulated result showed that the difference between the waveforms propagating through the bone without and with piezoelectricity was negligible. Finally, the spatial distributions of the electric fields in a human femur induced by ultrasound irradiation were simulated. The electric fields were changed by a bone fracture, which depended on piezoelectric anisotropy. In conclusion, the PE-FDTD method is considered to be useful for investigating the piezoelectric effect of bone.

  7. Power enhancement of piezoelectric transformers by adding thermal pad

    NASA Astrophysics Data System (ADS)

    Su, Y. H.; Liu, Y. P.; Vasic, D.; Costa, F.

    2012-04-01

    It is well known that power density of piezoelectric transformers is limited by mechanical stress. The power density of piezoelectric transformers calculated by the stress boundary can reach 330 W/cm3. However, no piezoelectric transformer has ever reached such a high power density in practice. The power density of the piezoelectric transformer is limited to 33 W/cm3 typically. This fact implies that there is another physical limitation in piezoelectric transformer. In fact, it is also known that piezoelectric material is constrained by vibration velocity. Once the vibration velocity is too large, the piezoelectric transformer generates heat until it cracks. To explain the instability of piezoelectric transformer, we will first model the relationship between vibration velocity and resulting heat by a physical feedback loop. It will be shown that the vibration velocity as well as the heat generation determines the loop gain. A large vibration velocity and heat may cause the feedback loop to enter into an unstable state. Therefore, to enhance the power capacity of piezoelectric transformer, the heat needs to be dissipated. In this paper, we used commercial thermal pads on the surface of the piezoelectric transformer to dissipate the heat. The mechanical current of piezoelectric transformers can move from 0.382A/2W to 0.972A/9W at a temperature of 55°C experimentally. It implies that the power capacity possibly increases 3 times in the piezoelectric material. Moreover, piezoelectric transformers that are well suited in applications of high voltage/low current becomes also well suited for low voltage/high current power supplies that are widely spread. This technique not only increases the power capacity of the piezoelectric transformer but also allows it to be used in enlarged practical applications. In this paper, the theoretical modeling will be detailed and verified by experiments.

  8. Piezoelectric multilayer actuator life test.

    PubMed

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

    2011-04-01

    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

  9. Development of a Piezoelectric Rotary Hammer Drill

    NASA Technical Reports Server (NTRS)

    Domm, Lukas N.

    2011-01-01

    The Piezoelectric Rotary Hammer Drill is designed to core through rock using a combination of rotation and high frequency hammering powered by a single piezoelectric actuator. It is designed as a low axial preload, low mass, and low power device for sample acquisition on future missions to extraterrestrial bodies. The purpose of this internship is to develop and test a prototype of the Piezoelectric Rotary Hammer Drill in order to verify the use of a horn with helical or angled cuts as a hammering and torque inducing mechanism. Through an iterative design process using models in ANSYS Finite Element software and a Mason's Equivalent Circuit model in MATLAB, a horn design was chosen for fabrication based on the predicted horn tip motion, electromechanical coupling, and neutral plane location. The design was then machined and a test bed assembled. The completed prototype has proven that a single piezoelectric actuator can be used to produce both rotation and hammering in a drill string through the use of a torque inducing horn. Final data results include bit rotation produced versus input power, and best drilling rate achieved with the prototype.

  10. Piezoelectric Ignition of Nanocomposite Energetic Materials

    DTIC Science & Technology

    2013-01-01

    incorporated a piezoelectric valveless micropump as the fuel delivery system and established the feasibility of DMFC in power electronics applications [2... micropump for fuel delivery in direct mathanol fuel cell (DMFC) devices," Journal of Power Sources, vol. 140, n 1, p. 72-80, 2005. [3] C. Rossi, K

  11. Non-bonded piezoelectric ultrasonic transducer

    DOEpatents

    Eoff, James M.

    1985-01-01

    A mechanically assembled non-bonded ultrasonic transducer includes a substrate, a piezoelectric film, a wetting agent, a thin metal electrode, and a lens held in intimate contact by a mechanical clamp. No epoxy or glue is used in the assembly of this device.

  12. Piezoelectric Nanoparticle-Polymer Composite Materials

    NASA Astrophysics Data System (ADS)

    McCall, William Ray

    Herein we demonstrate that efficient piezoelectric nanoparticle-polymer composite materials can be synthesized and fabricated into complex microstructures using sugar-templating methods or optical printing techniques. Stretchable foams with excellent tunable piezoelectric properties are created by incorporating sugar grains directly into polydimethylsiloxane (PDMS) mixtures containing barium titanate (BaTiO3 -- BTO) nanoparticles and carbon nanotubes (CNTs), followed by removal of the sugar after polymer curing. Porosities and elasticity are tuned by simply adjusting the sugar/polymer mass ratio and the electrical performance of the foams showed a direct relationship between porosity and the piezoelectric outputs. User defined 2D and 3D optically printed piezoelectric microstructures are also fabricated by incorporating BTO nanoparticles into photoliable polymer solutions such as polyethylene glycol diacrylate (PEGDA) and exposing to digital optical masks that can be dynamically altered. Mechanical-to-electrical conversion efficiency of the optically printed composite is enhanced by chemically altering the surface of the BTO nanoparticles with acrylate groups which form direct covalent linkages with the polymer matrix under light exposure. Both of these novel materials should find exciting uses in a variety of applications including energy scavenging platforms, nano- and microelectromechanical systems (NEMS/MEMS), sensors, and acoustic actuators.

  13. Piezoelectric Diffraction-Based Optical Switches

    NASA Technical Reports Server (NTRS)

    Spremo, Stevan; Fuhr, Peter; Schipper, John

    2003-01-01

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

  14. Flow Energy Piezoelectric Bimorph Nozzle Harvester

    NASA Technical Reports Server (NTRS)

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

    2014-01-01

    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.

  15. Zeroshift of piezoelectric accelerometers in pyroshock measurements

    NASA Astrophysics Data System (ADS)

    Chu, Anthony

    1987-01-01

    Zeroshift, a common measurement error in piezoelectric shock accelerometry, is any spurious output baseline shift which occurs after a pyroshock event. All components of the shock measurement system are analyzed for sources of zeroshift, and preventive practices are presented to aid in equipment selection, setup, and operation.

  16. Instrument For Simulation Of Piezoelectric Transducers

    NASA Technical Reports Server (NTRS)

    Mcnichol, Randal S.

    1996-01-01

    Electronic instrument designed to simulate dynamic output of integrated-circuit piezoelectric acceleration or pressure transducer. Operates in conjunction with external signal-conditioning circuit, generating square-wave signal of known amplitude for use in calibrating signal-conditioning circuit. Instrument also useful as special-purpose square-wave generator in other applications.

  17. Sensing Using Piezoelectric Chiral Polymer Fiber

    NASA Astrophysics Data System (ADS)

    Ito, Syuhei; Imoto, Kenji; Takai, Kyohei; Kuroda, Shintaro; Kamimura, Yuki; Kataoka, Takuya; Kawai, Naoki; Date, Munehiro; Fukada, Eiichi; Tajitsu, Yoshiro

    2012-09-01

    To realize a new polymer sensor fabricated from a piezoelectric chiral polymer fiber, we attempted to detect the response signal induced by the shear piezoelectricity of the chiral polymer poly(L-lactic acid) (PLLA) under the application of stress and strain, and we confirmed that the piezoelectric response signal was sufficiently large for use as a sensor signal. We then prepared a left-hand helical torsion coil (PLLA fiber left-hand coil), which was formed by drawing a PLLA fiber ten times. It was observed that, when twisted and released suddenly, the coil exhibited a torsion vibration, and we confirmed that the piezoelectric response signal followed the torsion vibration. Next, we prepared a system in which a PLLA fiber coil was linked to a personal computer used for simple image processing. The PLLA fiber left- and right-hand coils were placed on the arm of a subject, and the inward rotation and outward rotation of the forearm and upper arm were measured. Finally, using this system, we were able to visualize the rotation of the forearm and upper arm.

  18. Designing piezoelectric films for micro electromechanical systems.

    PubMed

    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

    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.

  19. Flow energy piezoelectric bimorph nozzle harvester

    NASA Astrophysics Data System (ADS)

    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

    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.

  20. Composite lateral electric field excited piezoelectric resonator.

    PubMed

    Zaitsev, B D; Shikhabudinov, A M; Borodina, I A; Teplykh, A A; Kuznetsova, I E

    2017-01-01

    The novel method of suppression of parasitic oscillations in lateral electric field excited piezoelectric resonator is suggested. Traditionally such resonator represents the piezoelectric plate with two electrodes on one side of the plate. The crystallographic orientation of the plate is selected so that the tangential components of electric field excite bulk acoustic wave with given polarization travelling along the normal to the plate sides. However at that the normal components of field excite the parasitic Lamb waves and bulk waves of other polarization which deteriorate the resonant properties of the resonator. In this work we suggest to separate the source of the HF electric field and resounded piezoelectric plate by air gap. In this case the tangential components of the field in piezoelectric plate do not practically weaken but normal components significantly decrease. This method is realized on the composite resonator having the structure "glass plate with rectangular electrodes - air gap - plate of 128 Y-X lithium niobate." It has been shown that there exist the optimal value of the width gap which ensure the good quality of series and parallel resonances in frequency range 3-4MHz with record values of Q-factor of ∼15,000 in both cases.