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Sample records for lead-free piezoelectric materials

  1. 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.

  2. 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

  3. 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.

  4. Evaluation of the performance of a lead-free piezoelectric material for energy harvesting

    NASA Astrophysics Data System (ADS)

    Machado, S. P.; Febbo, M.; Rubio-Marcos, F.; Ramajo, L. A.; Castro, M. S.

    2015-11-01

    Vibration-based energy harvesting has been explored as an auxiliary power source, which can provide small amounts of energy to power remote sensors installed in inaccessible locations. This paper presents an experimental and analytical study of an energy harvesting device using a lead-free piezoelectric material based on {{MoO}}3-doped ({{{K}}}0.44{{Na}}0.52{{Li}}0.04)({{Nb}}0.86{{Ta}}0.10{{Sb}}0.04){{{O}}}3 KNL-(NTS)Mo. The harvesting model corresponds to a cantilever beam with a KNL-(NTS)Mo piezoelectric disc attached to it. We analyze the effect of electromechanical coupling and load resistance on the generated electrical power. Electromechanical frequency response functions that relate the voltage output to the translational base acceleration are shown for experimental and analytical results.

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

    NASA Astrophysics Data System (ADS)

    Jeon, Yu Hong

    Piezoelectric materials have been widely used in electromechanical actuators, sensors, and ultrasonic transducers. Among these materials, lead zirconate titanate Pb(Zr1-xTix)O3 (PZT) has been primarily investigated due to its excellent piezoelectric properties. However, environmental concerns due to the toxicity of PbO have led to investigations into alternative materials systems. Bismuth-based perovskite piezoelectric materials such as (Bi0.5,Na0.5)TiO3 - (Bi0.5K 0.5)TiO3 (BNT - BKT), (Bi0.5,Na0.5 )TiO3 - (Bi0.5K0.5)TiO3 - BaTiO3(BNT - BKT - BT), (Bi0.5K 0.5)TiO3 - Bi(Zn0.5,Ti0.5)O 3 (BKT - BZT), and (Bi0.5,Na0.5)TiO 3 - (Bi0.5K0.5)TiO3 - Bi(Mg 0.5,Ti0.5)O3 (BNT - BKT - BMgT) have been explored as potential alternatives to PZT. These materials systems have been extensively studied in bulk ceramic form, however many of the ultimate applications will be in thin film embodiments (i.e., microelectromechanical systems). For this reason, in this thesis these lead-free piezoelectrics are synthesized in thin film form to understand the structure-property-processing relationships and their impact on the ultimate device response. Fabrication of high quality of 0.95BKT - 0.05BZT thin films on platinized silicon substrates was attempted by pulsed laser deposition. Due to cation volatility, deposition parameters such as substrate temperature, deposition pressure, and target-substrate distance, as well as target overdoping were explored to achieve phase pure materials. This route led to high dielectric loss, indicative of poor ferroelectric behavior. This was likely a result of the poor thin film morphology observed in films deposited via this method. Subsequently, 0.8BNT - 0.2BKT, 85BNT - 10BKT - 5BT, and 72.5BNT - 22.5BKT - 5BMgT (near morphotropic phase boundary composition) were synthesized via chemical solution deposition. To compensate the loss of A-site cations, overdoped precursor solutions were prepared. Crystallization after each spin cast layer were required to

  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. PMID:27010869

  7. Lead-free KNLNT Piezoelectric Ceramics for High-frequency Ultrasonic Transducer Application

    PubMed Central

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

    2010-01-01

    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 (K0.5Na0.5)0.97Li0.03(Nb0.9 Ta0.1)O3 (abbreviated as KNLNT-0.03/0.10) was fabricated and characterized. The material was found to have a clamped dielectric constant ε33S = ε0 = 890, piezoelectric coefficient d33 = 245 pC/N, electromechanical coupling factor kt = 0.42 and Curie temperature Tc > 300 °C. High-frequency (40 MHz) ultrasound transducers were successfully fabricated with the lead-free material. A representative lead-free transducer had a bandwidth of 45%, two-way insertion loss of −18 dB. This performance is comparable to reported performances of popular lead-based transducers. The comparison results suggest that the lead-free piezoelectric material may serve as an alternative to lead-based piezoelectric materials for high-frequency ultrasonic transducer applications. PMID:19121835

  8. 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. PMID:19121835

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

    NASA Astrophysics Data System (ADS)

    Patterson, Eric Andrew

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

  10. Domain evolution in lead-free thin film piezoelectric ceramics

    NASA Astrophysics Data System (ADS)

    Dubelman, Meredith Elissa

    Due to environmental and health concerns lead-free piezoelectric systems are currently being evaluated for use as replacements for lead-based ceramics. Sodium Bismuth Titanate, Na0.5Bi0.5TiO 3 (NBT) - based materials offer possible alternatives. NBT is a perovskite-type, ABO3, compound and is ferroelectric at room temperature. It has a relatively high Curie temperature, a large remnant polarization, and a high coercive field at room temperature. NBT can be modified by additives, such as BaTiO3 (BT), to improve its properties further. NBT-xBT was originally reported to have a morphotropic phase boundary which lies at x = 0.06. The structure transforms from rhombohedral for x < 0.06 to tetragonal for x > 0.06. However, recent studies have shown that for some compositions NBT-xBT develop a relaxor phase at room temperature. NBT xBT materials in the compositional range between 0.05 ≤ x ≤ 0.11have been shown to contain nanodomains embedded in a non-polar cubic matrix. The fluctuations of these nanodomains give rise to the relaxor behavior which in some cases is referred to as "relaxor antiferroelectric". In contrast to ferroelectric materials, in relaxor ferroelectrics thermal fluctuations can cause the poled nanodomains to relax to an unpoled state. It is necessary to understand local structure effects on the piezoelectric response at the grain level in order to develop materials with improved performance. Using Piezoresponse Force Microscopy (PFM), this study examines the domain motion within individual grains and domain evolution over time under locally applied electric fields as well as single-point hysteresis loop measurements in thin film NBT and NBT-xBT. These experiments provide an understanding of the domain behavior that cannot be acquired through bulk, macroscopic measurements. Thin films are fabricated using hydrothermal deposition and pulsed laser deposition. The films are highly oriented and exhibit relaxor behavior at room temperature.

  11. Sodium potassium niobate-based lead-free piezoelectric ceramics: Bulk and freestanding thick films

    NASA Astrophysics Data System (ADS)

    Li, Huidong

    2008-10-01

    Due to the toxicity of lead, there is an urgent need to develop lead-free alternatives to replace the currently dominant lead-based piezoelectrics such as lead zirconate titanate (PZT). (Na0.5K0.5)NbO 3 (NKN)-based piezoelectrics are promising because of their relatively high Curie temperatures and piezoelectric coefficients among the non-lead piezoelectrics. However, it is difficult to sinter. In this thesis study, a colloidal coating method was developed to improve the sintering of NKN. With this coating method, NKN with good piezoelectric properties can be produced without cold isostatic pressing. To improve the piezoelectric performance of NKN, we performed antimony (Sb) doping studies for a NKN-LN solid solution using the coating approach. It was found that Sb doping greatly improved the density and the piezoelectric properties of the NKN-LiNbO3 solid solution and optimized performance was found at 4%Sb. The reasons for the improved piezoelectric properties and density were discussed. Recently, a large enhancement in the piezoelectric performance under electric fields was discovered in polycrystalline lead magnesium niobate-lead titanate (PMN-PT) when the material was made into freestanding film geometry. Here, for the first time, we show a similar effect was also observed in a lead-free system, (Na0.5K0.5)0.945Li0.055Nb 0.96Sb0.04O3. At 6-8 kV/cm, a giant --d 31 value of 1700 pm/V was achieved, 20 times higher than the value of bulk counterpart. The enhancement was found to result from the ease of domain motion imparted by the freestanding film geometry, and the magnitude of the enhancement can be affected by the electrode layer (a non-piezoelectric) thickness. The freestanding geometry provides a new approach to greatly improve the piezoelectric performance of the current lead-free systems.

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

    DOE PAGESBeta

    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 piezoelectricmore » materials.« less

  13. Lead-free piezoelectric ceramics and thin films.

    PubMed

    Safari, Ahmad; Abazari, Maryam

    2010-10-01

    Recent progress in lead-free piezoelectric ceramics and thin films with special emphasis on alkaline niobatebased and bismuth sodium titanate-based systems is reviewed concisely. Modifications of potassium sodium niobate (KNN) ceramics are presented and subsequent improvements in the electrical properties are summarized. Special attention is devoted to the phase diagram of the KNN system when a solid solution is formed with other perovskite niobates and titanates. Impact of A-site and B-site dopants on the electromechanical properties of KNN ceramics are distinguished in view of transition temperatures. It is shown that the addition of most A-site and B-site dopants reduces the transition temperatures and improves the piezoactivity at room temperature. This is attributed to the shift of polymorphic transition from tetragonal to orthorhombic phase in the vicinity of room temperature. In contrast, formation of a solid solution of KNN with 18 mol% AgNbO₃ revealed a significant enhancement of properties without a notable change in the transition temperatures. Also, a bismuth sodium titanate (BNT) composition is introduced with particular emphasis on its binary and ternary derivatives. Moderate piezoelectric properties reported at the morphotropic phase boundaries, formed in BNT-based solid solutions are also represented. Advances on thin films based on these two compositions are evaluated and challenges involved with development of stoichiometric thin films with low leakage current are discussed. PMID:20889401

  14. 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.

  15. Development of lead-free piezoelectric thin films by pulsed laser deposition

    NASA Astrophysics Data System (ADS)

    Abazari Torghabeh, Maryam

    As a high performance piezoelectric material widely used in sensors, actuators and other electronic devices, lead zirconate titanate (PZT) ceramics have been the center of attention for many years. However, the toxicity of these materials and their exposure to the environment during processing steps, such as calcination, sintering, machining as well as problems in recycling and disposal have been major concerns regarding their usage all around the globe for the past couple of decades. Consequently, utilizing lead-based materials for many commercial applications have been recently restricted in Europe and Asia and measures are being taken in United States as well. Therefore, there is an urgent need for lead-free piezoelectrics whose properties are comparable to those of well-known PZT materials. Recently, the discovery of ultra-high piezoelectric activity in the ternary lead-free KNaNbO3-LiTaO 3-LiSbO3 (KNN-LT-LS) and (Bi,Na)TiO3-(Bi,K)TiO 3-BaTiO3 (BNT-BKT-BT) systems have given hope for alternatives to PZT. Furthermore, the demand for new generation of environment-friendly functional devices, utilizing piezoelectric materials, inspired a new surge in lead-free piezoelectric thin film research. In this study, an attempt has been made to explore the development of lead-free piezoelectric thin films by Pulsed Laser Deposition (PLD) on SrTiO 3 substrate. While the growth and development process of KNN-LT-LS thin films was the primary goal of this thesis, a preliminary effort was also made to fabricate and characterize BNT-BKT-BT thin films. In a comprehensive and systematic process optimization study in conjunction with X-ray diffractometry, the phase evolution, stoichiometry, and growth orientation of the films are monitored as a function of deposition conditions including temperature and ambient oxygen partial pressure. Processing parameters such as substrate temperature and pressure are shown to be highly dominant in determining the phase and composition of the

  16. 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

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

    PubMed

    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

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

    NASA Astrophysics Data System (ADS)

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

    2015-03-01

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

  19. Structural, Dielectric, Piezoelectric and Ferroelectric Characterization of NBT-BT Lead-Free Piezoelectric Ceramics

    NASA Astrophysics Data System (ADS)

    Shanmuga Sundari, S.; Kumar, Binay; Dhanasekaran, R.

    2013-05-01

    Lead free piezoelectric 0.94(Na0.5Bi0.5)TiO3-0.06BaTiO3 (NBT-BT) ceramics were synthesized in MPB composition by conventional solid state reaction method. The crystalline nature of NBT-BT ceramic was studied by XRD and the size of the grains are determined by SEM. The X- ray diffraction results reveal that Ba2+ diffuse into the Na0.5 Bi0.5TiO3 lattices to form a solid solution with a pure perovskite structure. Because of the strong ferroelectricity and MPB, the ceramics exhibit high piezoelectric properties: d33 = 206 pC/N. Td (depolarization temperature) and Tm (temperature at with the dielectric constant epsilonr reaches a maximum) were observed through the phase transition in dielectric studies. In addition, the prepared ceramic exhibits relaxor characteristic, which probably results from the cation disordering in the 12fold coordination sites. Pr and Ec of the prepared ceramics were determined from the P-E hysteresis loop.

  20. Effect of poling process on piezoelectric properties of BCZT - 0.08 wt.% CeO2 lead-free ceramics

    NASA Astrophysics Data System (ADS)

    Chandrakala, E.; Praveen, J. Paul; Das, Dibakar

    2016-05-01

    The properties of lead free piezoelectric materials can be tuned by suitable doping in the A and B sites of the perovskite structure. In the present study, cerium has been identified as a dopant to investigate the piezoelectric properties of lead-free BCZT system. BCZT - 0.08 wt.%CeO2 lead-free ceramics have been synthesized using sol-gel technique and the effects of CeO2 dopant on their phase structure and piezoelectric properties were investigated systematically. Poling conditions, such as temperature, electric field, and poling time have been optimized to get enhanced piezoelectric response. The optimized poling conditions (50°C, 3Ec and 30min) resulted in high piezoelectric charge coefficient d33 ~ 670pC/N, high electromechanical coupling coefficient kp ~ 60% and piezoelectric voltage coefficient g33 ~ 14 mV.m/N for BCZT - 0.08wt.% CeO2 ceramics.

  1. Large strain under a low electric field in lead-free bismuth-based piezoelectrics

    NASA Astrophysics Data System (ADS)

    Ullah, Aman; Won Ahn, Chang; Ullah, Amir; Won Kim, Ill

    2013-07-01

    In this letter, the composition and electric field dependent strain behavior of (1 - x)Bi0.5(Na0.78K0.22)0.5TiO3-xBi(Mg0.5Ti0.5)O3 (BNKT-BMT) were investigated to develop lead-free piezoelectric materials with a large strain response at a low driving field for actuator applications. A large strain of 0.35% (Smax/Emax = 636 pm/V) at an applied field of 55 kV/cm was obtained with a composition of 4 mol. % BMT. In particular, the electric field required to deliver large strains was reduced to a level that revealed not only a large Smax/Emax of 542 pm/V at a driving field as low as 35 kV/cm, but also remarkably suppressed the large hysteresis.

  2. 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.

  3. 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

  4. 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. PMID:26436199

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

    PubMed

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

    2016-01-01

    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

  6. 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

  7. 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

  8. 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. PMID:24474129

  9. Morphotropic NaNbO3-BaTiO3-CaZrO3 lead-free ceramics with temperature-insensitive piezoelectric properties

    NASA Astrophysics Data System (ADS)

    Zuo, Ruzhong; Qi, He; Fu, Jian

    2016-07-01

    A morphotropic NaNbO3-based lead-free ceramic was reported to have temperature-insensitive piezoelectric and electromechanical properties (d33 = 231 pC/N, kp = 35%, Tc = 148 °C, and low-hysteresis strain ˜0.15%) in a relatively wide temperature range. This was fundamentally ascribed to the finding of a composition-axis vertical morphotropic phase boundary in which coexisting ferroelectric phases are only compositionally driven and thermally insensitive. Both phase coexistence and nano-scaled domain morphology deserved well enhanced electrical properties, as evidenced by means of synchrotron x-ray diffraction and transmission electron microscopy. Our study suggests that the current lead-free ceramic would be a very promising piezoelectric material for actuator and sensor applications.

  10. Study of BNT-BKT-BT lead-free piezoelectric ceramics and their application in piezoelectric devices

    NASA Astrophysics Data System (ADS)

    Choy, Siu Hong

    Lead-free piezoelectric ceramics, 0.90Bi0.5Na 0.5TiO3-0.05Bi0.5K0.5TiO3-0.05BaTiO 3 (BNKBT-5), have been fabricated by a solid-state reaction method. The dielectric, piezoelectric and ferroelectric properties of the ceramics have been measured and the microstructures studied by X-ray diffraction and SEM. In the ferroelectric hysteresis loop measurements, Pr ˜ 28.5 muC/cm2 and Ec ˜3.5 MV/m have been observed. The electromechanical coupling coefficients kp and kt are 0.31 and 0.46, respectively. Those properties are comparable to that of lead-based ceramics such as PZT. Three different compounds, including CeO2, Ca2Fe 2O5 and (Bi0.5Li0.5)TiO3, have been used as additives/dopants to improve the properties of BNKBT-5. All the samples with different compositions have been characterized. The measured properties are compared with that of BNKBT-5. It has been found that the BNKBT-5 doped with 1.5 mol% of (Bi0.5Li0.5)TiO3, namely BNKLBT-1.5, has the best performance. It can enhance kp, kt, Qm, Pr, and can reduce tandelta but do not lower the depolarization temperature. Two different types of devices have been fabricated using BNKBT-5 and BNKLBT-1.5 ceramic rings. The first device is compressive-type accelerometers. A PZT accelerometer with similar structure has also been fabricated for comparison. The accelerometers are calibrated using a back-to-back calibration method against a standard reference accelerometer. Within the +/-2.5% tolerance, the mean sensitivity of PZT, BNKBT and BNKLBT accelerometer is 4.34 pC/ms -2 (50 Hz to 8.24 kHz), 2.24 pC/ms-2 (50 Hz to 10.1 kHz) and 2.97 pC/ms-2 (50 Hz to 12.45 kHz), respectively. The BNKLBT-1.5 accelerometer has a reasonably high sensitivity and the broadest sensing frequency range which would be the most preferable choice for structural health monitoring applications. The second device is ultrasonic wirebonding transducers for microelectronic packaging. It has been found that if titanium is used as the metal parts in the

  11. Synthesis and piezoelectric properties of BaTiO3-doped lead-free Li0.12Na0.88NbO3 ceramics

    NASA Astrophysics Data System (ADS)

    Mitra, Supratim; Rathore, Deepshikha

    2016-05-01

    New lead-free (1-x)Li0.12Na0.88NbO3-xBaTiO3 [(1-x)LNN-xBT] (x = 0.0, 0.1, 0.2, 0.3, 0.4) piezoelectric ceramics have been synthesized using conventional ceramics processing route. The phase analysis revealed that material undergoes two phase transition: orthorhombic to tetragonal around x = 0.2 and tetragonal to cubic for x ≥ 0.3. The microstructural analysis confirms a homogeneous solid solution, well developed grains and a high sintered density. Ferroelectric and piezoelectric properties were investigated and the material is found suitable for memory, piezoelectric vibrators and low power transducers applications.

  12. 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.

  13. 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

    2016-07-01

    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. PMID:27334673

  14. Phase Structures and Piezoelectric Properties of (K,Na,Li)(Nb,Sb)O3-(Bi,Ag)ZrO3 Lead-Free Ceramics

    NASA Astrophysics Data System (ADS)

    Li, ZhiPeng; Zhang, Yang; Li, LingYu; Li, JianKang; Zhai, JiWei

    2016-06-01

    Samples in the pseudoternary lead-free piezoelectric ceramic system 0.94KNN-(0.06 - x)LiSbO3- x(Bi0.5Ag0.5)ZrO3 were prepared using a solid-state reaction technique and their phase transition behavior and electrical properties studied. Results showed that BAZ diffuses into KNN-LS to form a new solid solution, and induces a phase transition from tetragonal to rhombohedral phase with increase of x. At 0.02 ≤ x ≤ 0.03, coexistence of tetragonal and rhombohedral phases is observed, and enhanced piezoelectric properties are achieved in this composition range due to the polymorphic phase transition near room temperature. Doping with (Bi0.5Ag0.5)ZrO3 effectively promotes densification and further enhances the piezoelectric and dielectric properties of of the ceramics. Moreover, the ceramic with x = 0.025 possesses excellent electrical properties of k p = 42.3%, {d_{33}^{*}} = 320 pm/V and d 33 = 235 pC/N, tan δ = 0.039, and T c = 326°C. This result indicates that 0.94KNN-0.035LS-0.025BAZ ceramic is a promising lead-free material for practical applications.

  15. Lead-free piezoceramics

    NASA Astrophysics Data System (ADS)

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

    2004-11-01

    Lead has recently been expelled from many commercial applications and materials (for example, from solder, glass and pottery glaze) owing to concerns regarding its toxicity. Lead zirconium titanate (PZT) ceramics are high-performance piezoelectric materials, which are widely used in sensors, actuators and other electronic devices; they contain more than 60 weight per cent lead. Although there has been a concerted effort to develop lead-free piezoelectric ceramics, no effective alternative to PZT has yet been found. Here we report a lead-free piezoelectric ceramic with an electric-field-induced strain comparable to typical actuator-grade PZT. We achieved this through the combination of the discovery of a morphotropic phase boundary in an alkaline niobate-based perovskite solid solution, and the development of a processing route leading to highly <001> textured polycrystals. The ceramic exhibits a piezoelectric constant d33 (the induced charge per unit force applied in the same direction) of above 300picocoulombs per newton (pCN-1), and texturing the material leads to a peak d33 of 416pCN-1. The textured material also exhibits temperature-independent field-induced strain characteristics.

  16. Piezoelectric/photoluminescence effects in rare-earth doped lead-free ceramics

    NASA Astrophysics Data System (ADS)

    Yao, Qirong; Wang, Feifei; Jin, Chengchao; Tang, Yanxue; Wang, Tao; Shi, Wangzhou

    2013-10-01

    In the present work, we report the environmentally-friendly multifunctional effects—piezoelectric/photoluminescence effects, which originated from the combination of the electromechanical properties and the photoluminescence effect through introducing the rare-earth elements (Pr and Eu) into the (Bi0.5Na0.5)TiO3-BaTiO3 ceramics with the composition around the morphotropic phase boundary. Compared to the pure piezoelectric ceramic, the proposed system simultaneously exhibited enhanced ferroelectric, piezoelectric, dielectric properties along with strong photoluminescence effects, which exhibited potential applications in sensor, and electro-mechano-optical integration. In addition, the present work also provides a promising path for us to fabricate multifunctional composites.

  17. Nanoscale Atomic Displacements Ordering for Enhanced Piezoelectric Properties in Lead-Free ABO3 Ferroelectrics.

    PubMed

    Pramanick, Abhijit; Jørgensen, Mads R V; Diallo, Souleymane O; Christianson, Andrew D; Fernandez-Baca, Jaime A; Hoffmann, Christina; Wang, Xiaoping; Lan, Si; Wang, Xun-Li

    2015-08-01

    In situ synchrotron X-ray diffuse scattering and inelastic neutron scattering measurements from a prototype ABO3 ferroelectric single-crystal are used to elucidate how electric fields along a nonpolar direction can enhance its piezoelectric properties. The central mechanism is found to be a nanoscale ordering of B atom displacements, which induces increased lattice instability and therefore a greater susceptibility to electric-field-induced mechanical deformation. PMID:26076654

  18. A new lead-free radiation shielding material for radiotherapy.

    PubMed

    Yue, Kun; Luo, Wenyun; Dong, Xiaoqing; Wang, Chuanshan; Wu, Guohua; Jiang, Mawei; Zha, Yuanzi

    2009-02-01

    Lead has recently been recognised as a source of environmental pollution, including the lead used for radiation shielding in radiotherapy. The bremsstrahlung radiation caused by the interaction between the electron beam and lead may reduce the accuracy of radiotherapy. To avoid the use of lead, a new material composed of tungsten and hydrogenated styrene-butadiene-styrene copolymer is studied with the Monte Carlo (MC) method and experiment in this paper. The component of the material is chosen after simulation with the MC method and the practical measurement is taken to validate the shielding ability of the material. The result shows that the shielding ability of the new material is good enough to fulfill the requirement for application in radiotherapy. Compared with lead alloy, the present new material is so flexible that can be easily customized into arbitrary shapes. Moreover, the material is environmentally friendly and can be recycled conveniently. Therefore, the material can be used as an effective lead substitute for shielding against electron beams in radiotherapy. PMID:19329510

  19. Phase Structure, Piezoelectric and Multiferroic Properties of SmCoO3-Modified BiFeO3-BaTiO3 Lead-Free Ceramics

    NASA Astrophysics Data System (ADS)

    Jiang, Na; Tian, Mijie; Luo, Lingling; Zheng, Qiaoji; Shi, Dongliang; Lam, Kwok Ho; Xu, Chenggang; Lin, Dunmin

    2016-01-01

    (0.75- x)BiFeO3-0.25BaTiO3- xSmCoO3 + 1 mol.% MnO2 lead-free multiferroic ceramics were synthesized by a conventional ceramic fabrication technique. The effects of SmCoO3 on phase structure, piezoelectricity and multiferroicity of the ceramics were studied. All the ceramics can be well sintered at a low sintering temperature of 960°C. The crystalline structure of the ceramics is transformed from rhombohedral to tetragonal symmetry with increasing the amount of SmCoO3. A morphotropic phase boundary of rhombohedral and tetragonal phases is formed at x = 0.01-0.04. A small amount of SmCoO3 is shown to improve the ferroelectric, piezoelectric and magnetoelectric properties of the ceramics. For the ceramics with x = 0.01-0.03, enhanced resistivity ( R ˜ 1.2 × 109 Ω cm to 2.1 × 109 Ω cm), piezoelectricity ( d 33 ˜ 65 pC/N to 106 pC/N) and ferroelectricity ( P r ˜ 6.38 μC/cm2 to 22.89 μC/cm2) are obtained. The ferromagnetism of the materials is greatly enhanced by the doping of SmCoO3 such that a very high magnetoelectric coefficient of ˜742 mV/(cm Oe) is obtained at x = 0.01, suggesting a promising potential in multiferroic devices.

  20. Ultrahigh strain response with fatigue-free behavior in (Bi0.5Na0.5)TiO3-based lead-free piezoelectric ceramics

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

    In this letter, we report a lead-free piezoelectric ceramic system (Bi0.5Na0.5)1-x Ba x Ti0.98 (Fe0.5Sb0.5)0.02O3 which shows a surprisingly high field-induced nonlinear strain of 0.57% comparable to those obtained in Pb-based antiferroelectrics. The ultrahigh strain response of the composition stems from the composition proximity to the ferroelectric-nonpolar phase boundary, which leads to reversible transformation between a nonpolar phase and a polar ferroelectric phase under cyclic fields. In particular, this material is very attractive for its exceptionally good fatigue resistance (up to 106 cycles) and high temperature stability (25-100 °C) due to its stable nonpolar phase and lower defect density. These findings render the current material a great opportunity for novel applications in ultra-large stroke and nonlinear actuators demanding improved cycling and thermal reliabilities.

  1. Large piezoelectric properties in KNN-based lead-free single crystals grown by a seed-free solid-state crystal growth method

    NASA Astrophysics Data System (ADS)

    Yang, Jie; Zhang, Faqiang; Yang, Qunbao; Liu, Zhifu; Li, Yongxiang; Liu, Yun; Zhang, Qiming

    2016-05-01

    We report lead-free single crystals with a nominal formula of (K0.45Na0.55)0.96Li0.04NbO3 grown using a simple low-cost seed-free solid-state crystal growth method (SFSSCG). The crystals thus prepared can reach maximum dimensions of 6 mm × 5 mm × 2 mm and exhibit a large piezoelectric coefficient d33 of 689 pC/N. Moreover, the effective piezoelectric coefficient d33 * , obtained under a unipolar electric field of 30 kV/cm, can reach 967 pm/V. The large piezoelectric response plus the high Curie temperature (TC) of 432 °C indicate that SFSSCG is an effective approach to synthesize high-performance lead-free piezoelectric single crystals.

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

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

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

  3. A comparison of different powder compaction processes adopted for synthesis of lead-free piezoelectric ceramics

    NASA Astrophysics Data System (ADS)

    Mahesh, M. L. V.; Bhanu Prasad, V. V.; James, A. R.

    2016-04-01

    Barium zirconium titanate, Ba(Zr0.15Ti0.85)O3 nano-crystalline powders were synthesized using high energy ball milling. The calcined powders were compacted adopting two different approaches viz. the conventional uniaxial pressing and cold-isostatic pressing (CIP) and the compacts were sintered at 1350 °C. A single phase perovskite structure was observed in both cases. BZT ceramics compacted using CIP technique exhibited enhanced dielectric and ferroelectric properties compared to ceramics compacted by uniaxial pressing. The polarization current peaks have been used in this paper as an experimental evidence to prove the existence of ferroelectricity in the BZT ceramics under study. The peak polarization current was found to be ~700% higher in case of cold iso-statically compacted ceramics. Similarly electric field induces strain showed a maximum strain ( S max) of 0.08% at an electric field of 28 kV/cm. The dielectric and ferroelectric properties observed are comparable to single crystals of the same material.

  4. 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

  5. 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.

  6. 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

    2016-01-01

    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. PMID:27160075

  7. Reactive sintering of (K0.5Bi0.5)TiO3-BiFeO3 lead-free piezoelectric ceramics

    NASA Astrophysics Data System (ADS)

    Fisher, John G.; Kim, Min-Gu; Kim, Daeung; Cha, Su-Jeong; Vu, Hung Van; Nguyen, Dieu; Kim, Young-Hun; Moon, Su-Hyun; Lee, Jong-Sook; Hussain, Ali; Kim, Myong-Ho

    2015-05-01

    Ceramics based on BiFeO3 are potential lead-free replacements for Pb(Zr,Ti)O3 in a variety of applications such as sensors, transducers and actuators. Recently, ceramics in the (K0.5Bi0.5)TiO3-BiFeO3 system were developed which have excellent piezoelectric properties. However, these ceramics are difficult to sinter to high density. The present work studies the use of reactive sintering to prepare 0.4(K0.5Bi0.5)TiO3-0.6BiFeO3 ceramics. Undoped and MnO-doped powders were prepared by ball milling K2CO3, (BiO)2CO3, TiO2, α-FeO(OH) and MnCO3 in ethanol with zirconia milling media. The decomposition and calcination reactions of the starting materials were studied using differential scanning calorimetry/thermogravimetric analysis, X-ray diffraction and Fourier transform infra-red analysis. Samples were sintered in the temperature range from 1000 to 1075°C and their structures and microstructures examined using X-ray diffraction, micro-Raman scattering and scanning electron microscopy. MnO doping reduced the rhombohedral distortion of the unit cell. The dielectric, ferroelectric and piezoelectric properties of selected undoped and MnO-doped samples were measured. Both undoped and MnO-doped samples displayed relaxor-type behavior. MnO doping reduced the conductivity of the samples, which exhibit a well-defined activation energy of 1.21 eV. Undoped samples have strain vs. electric field properties comparable to those reported in the literature.

  8. Interface cracks in piezoelectric materials

    NASA Astrophysics Data System (ADS)

    Govorukha, V.; Kamlah, M.; Loboda, V.; Lapusta, Y.

    2016-02-01

    Due to their intrinsic electromechanical coupling behavior, piezoelectric materials are widely used in sensors, actuators and other modern technologies. It is well known that piezoelectric ceramics are very brittle and susceptible to fracture. In many cases, fracture occurs at interfaces as debonding and cracks. This leads to an undesired degradation of electrical and mechanical performance. Because of the practical and fundamental importance of the problem, interface cracks in piezoelectric materials have been actively studied in the last few decades. This review provides a comprehensive survey of recent works on cracks situated at the interface of two materials, at least one of which has piezoelectric or piezoelectromagnetic properties. Different electric boundary conditions along the crack faces are discussed. The oscillating and contact zone models for in-plane straight interface cracks between two dissimilar piezoelectric materials or between piezoelectric and non-piezoelectric ones are reviewed. Different peculiarities related to the investigation of interface cracks in piezoelectric materials for the anti-plane case, for functionally graded and thermopiezoelectric materials are presented. Papers related to magnetoelectroelastic bimaterials, to steady state motion of interface cracks in piezoelectric bimaterials and to circular arc-cracks at the interface of piezoelectric materials are reviewed, and various methods used to address these problems are discussed. The review concludes with an outlook on future research directions.

  9. Improvement of the piezoelectric properties in (K,Na)NbO3-based lead-free piezoelectric ceramic with two-phase co-existing state

    NASA Astrophysics Data System (ADS)

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

    2015-06-01

    Two phases of (K,Na)NbO3 (KNN) co-exist in a KNN-based composite lead-free piezoelectric ceramic 0.910(K1-xNax)0.86Ca0.04Li0.02Nb0.85O3-δ-0.042K0.85Ti0.85Nb1.15O5-0.036BaZrO3-0.0016Co3O4- 0.0025Fe2O3-0.0069ZnO 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, kp = 0.56, has been observed at the composition x = 0.56.

  10. First-principles calculation of the effects of Li-doping on the structure and piezoelectricity of (K0.5Na0.5)NbO3 lead-free ceramics.

    PubMed

    Yang, D; Wei, L L; Chao, X L; Yang, Z P; Zhou, X Y

    2016-03-01

    The crystal structures of the lead-free piezoelectric ceramics (K0.5Na0.5)NbO3 and (K0.5Na0.5)0.94Li0.06NbO3 prepared by a solid-state method were investigated using first-principles calculations. The calculated values of piezoelectricity were in good agreement with the experimental data. We found that the primary contribution to piezoelectricity in this material comes from the hybridization of the O 2p and Nb 4d orbitals, which causes a change in the Nb-O bond length and the distortion of the Nb-O octahedral structure. Analysis of the band structure and the total density of states revealed that Li-doped (K0.5Na0.5)NbO3 enhances hybridization of the O 2p and Nb 4d orbitals. This hybridization enhancement further reduces the Nb-O1 bond length and enhances the distortion of the Nb-O octahedron along the [001] direction, which may be the main reason for the improvement of the piezoelectric properties. In addition, the piezoelectric coefficients are calculated here, which show the same trend as the experimental results. PMID:26906892

  11. Determination of crystallographic orientation of lead-free piezoelectric (K,Na)NbO3 epitaxial thin films grown on SrTiO3 (100) surfaces

    NASA Astrophysics Data System (ADS)

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

    2014-03-01

    Crystallographic structure of sol-gel-processed lead-free (K,Na)NbO3 (KNN) epitaxial films on [100]-cut SrTiO3 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 SrTiO3 (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.

  12. Evaluation of Diffusion Barrier Between Lead-Free Solder Systems and Thermoelectric Materials

    NASA Astrophysics Data System (ADS)

    Lin, T. Y.; Liao, C. N.; Wu, Albert T.

    2012-01-01

    The intermetallic compound SnTe rapidly formed at interfaces between p-type bismuth telluride (Bi0.5Sb1.5Te3) thermoelectric materials and lead-free solders. The intermetallic compound influences the mechanical properties of the joints and the reliability of the thermoelectric modules. Various lead-free solder alloys, Sn-3.5Ag, Sn-3Ag-0.5Cu, Sn-0.7Cu, and Sn-2.5Ag-2Ni, were used to investigate the interfacial reactions. The results thus obtained show that Ag and Cu preferentially diffused into the Te-rich phase in Bi0.5Sb1.5Te3, so layers of Ag-Te and Cu-Te compounds could not form an effective diffusion barrier. Electroless nickel-phosphorus was plated at the interfaces to serve as a diffusion barrier, and the (Cu,Ni)6Sn5 compound formed instead of SnTe. Furthermore, the intermetallic compound NiTe formed between nickel- phosphorus and Bi0.5Sb1.5Te3 and also served as a diffusion barrier. A plot of thickness as a function of annealing time yielded the growth kinetics of the intermetallic compounds in the thermoelectric material systems. The activation energy for the growth of the NiTe intermetallic compound is 111 kJ/mol.

  13. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2016-03-01

    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.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. Electronic supplementary information (ESI) available: Detailed descriptions on

  15. 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

    2016-03-17

    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. PMID:26349623

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

    PubMed

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

    2013-02-01

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

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

    SciTech Connect

    Tian, Ye; Chao, Xiaolian E-mail: yangzp@snnu.edu.cn; Wei, Lingling; Liang, Pengfei; Yang, Zupei E-mail: yangzp@snnu.edu.cn; Jin, Li

    2014-03-17

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

  18. 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.

  19. Response of intergrown microstructure to an electric field and its consequences in the lead-free piezoelectric bismuth sodium titanate

    SciTech Connect

    Liu Yun; Noren, Lasse; Studer, Andrew J.; Withers, Ray L.; Guo Yiping; Li Yongxiang; Yang Hui; Wang Jian

    2012-03-15

    We investigate the R3c average structure and micro-structure of the ceramic Bi{sub 0.5}Na{sub 0.5}TiO{sub 3} (BNT) in situ under applied electric fields using diffraction techniques. Electron diffraction implies the presence of significant octahedral tilt twin disorder, corresponding to the existence of a fine scale intergrown microstructural (IGMS) 'phase' within the R3c rhombohedral average structure matrix. A careful neutron refinement suggests not only that the off-centre displacements of the cations relative to the oxygens in the R3c regions increases systematically on application of an electric field but also that the phase fraction of the IGMS regions increases systematically. The latter change in phase fraction on application of the electric field enhances the polar displacement of the cations relative to the oxygen anions and affects the overall strain response. These IGMS regions form local polar nano regions that are not correlated with one another, resulting in polarisation relaxation and strain behaviour observed in BNT-containing materials. - Graphical abstract: The intergrown microstructure at very fine scales within the R3c rhombohedral phase matrix of BNT, originating from octahedral tilt twinning disorder, will increase with respect to an external field. Highlights: Black-Right-Pointing-Pointer The existence of an intergrown microstructural 'phase' within the average structure matrix. Black-Right-Pointing-Pointer This phase fraction of the intergrown microstructural regions changes. Black-Right-Pointing-Pointer Such regions form local polar nano regions that are not correlated with one another.

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

    NASA Astrophysics Data System (ADS)

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

    2013-10-01

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

  1. 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. PMID:26735739

  2. 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.

  3. 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).

  4. Long-period modulated structure and electric-field-induced structural transformation in N a0.5B i0.5Ti O3 -based lead-free piezoelectrics

    NASA Astrophysics Data System (ADS)

    Khatua, Dipak Kumar; Senyshyn, Anatoliy; Ranjan, Rajeev

    2016-04-01

    N a0.5B i0.5Ti O3 - based lead-free piezoelectrics exhibiting giant piezostrain are technologically interesting materials for actuator applications. The lack of clarity with regard to the structure of the nonpolar phase of this system has hindered the understanding of the structural mechanism associated with the giant piezostrain and other related phenomena. In this paper, we have investigated the structure and field-induced phase transformation behavior of a model system (0.94 -x )N a0.5B i0.5Ti O3-0.06 BaTi O3-x K0.5N a0.5Nb O3 (0.0 ≤x ≤0.025 ). A detailed structural analysis using neutron powder diffraction revealed that the nonpolar phase is neither cubic nor a mixture of rhombohedral (R 3 c ) and tetragonal (P 4 b m ) phases as commonly reported in literature but exhibits a long-period modulated structure, which is most probably of the type √{2 }×√{2 }×n with n =16 . Our results suggest that the giant piezoelectric strain is associated with a field-induced phase transformation of the long-period modulated structure to rhombohedral R 3 c structure above a critical field. We also demonstrate that the giant piezostrain is lost if the system retains a fraction of the field-induced R 3 c phase. A possible correlation among depolarization temperature, giant piezostrain, and its electrical fatigue behavior has also been indicated.

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

    PubMed

    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

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

    NASA Astrophysics Data System (ADS)

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

    2016-05-01

    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.

  7. 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

  8. Enhanced piezoelectricity in (1 -x)Bi1.05Fe1-yAyO3-xBaTiO3 lead-free ceramics: site engineering and wide phase boundary region.

    PubMed

    Zheng, Ting; Jiang, Zhenggen; Wu, Jiagang

    2016-07-28

    Site engineering has been employed to modulate the piezoelectric activity of high temperature (1 -x)Bi1.05Fe1-yScyO3-xBaTiO3 lead-free ceramics fabricated by a conventional solid-state method together with a quenching technique. The effects of x and y content on the phase structure, microstructure, and electrical properties have been investigated in detail. A wide rhombohedral (R) to pseudo-cubic (C) phase boundary was formed in the ceramics with x = 0.30 and 0 ≤y≤ 0.07, thus leading to enhanced piezoelectricity (d33 = 120-180 pC N(-1)), ferroelectricity (Pr = 19-22 μC cm(-2)) and a high Curie temperature (TC = 478-520 °C). In addition, the influence of different element substitutions for Fe(3+) on phase structure and electrical behavior was also investigated. Improved piezoelectricity (d33 = 160-180 pC N(-1)) and saturated P-E loops can be simultaneously achieved in the ceramics with A = Sc, Ga, and Al due to the R-C phase boundary. As a result, site engineering may be an efficient way to modulate the piezoelectricity of BiFeO3-BaTiO3 lead-free ceramics. PMID:27357104

  9. Enhanced piezoelectric properties of BaZrO3-substituted 0.67BiFeO3-0.33BaTiO3 lead-free ceramics

    NASA Astrophysics Data System (ADS)

    Park, J. S.; Lee, M. H.; Kim, D. J.; Kim, M.-H.; Song, T. K.; Kim, S. W.; Kim, W.-J.; Kumar, S.

    2015-04-01

    Lead-free ceramics with compositions of (1- x)[0.67Bi1.05FeO3-0.33BaTiO3]- xBaZrO3 ( x = 0.00, 0.01, 0.02, 0.03, 0.04, and 0.05) [BF-BT-BZ x] have been prepared through a conventional solid-state reaction method. The effects of BZ substitution on the crystal structural, microstructural, piezoelectric, and electrical properties of the ceramics were investigated. The X-ray diffraction patterns revealed that all ceramics were formed with a mixed structure of rhombohedral and tetragonal perovskite phases. For x = 0.03, good ferroelectric and piezoelectric properties were observed: 2 P r = 43 μC/cm2 and 2 E c = 61 kV/cm. The static- and dynamic-piezoelectric constants were observed to be 52 pC/N and 330 pm/V, respectively.

  10. 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.

  11. How to Identify Lead-Free Certification Marks for Drinking Water System & Plumbing Materials - Presentation

    EPA Science Inventory

    In 2011, Congress passed the “Reduction of Lead in Drinking Water Act,” which effectively reduces the lead content allowed in material used for potable water plumbing. The Act, which will go into effect on January 4, 2014, changes the definition of “lead-free” by reducing allowed...

  12. How to Identify Lead-Free Certification Marks for Drinking Water System & Plumbing Materials

    EPA Science Inventory

    In 2011, Congress passed the “Reduction of Lead in Drinking Water Act,” which effectively reduces the lead content allowed in material used for potable water plumbing. The Act, which will go into effect on January 4, 2014, changes the definition of “lead-free” by reducing allowed...

  13. Designing lead-free and stable perovskite materials for photovoltaic applications

    NASA Astrophysics Data System (ADS)

    Sun, Yiyang; Zhang, Shengbai

    A critical barrier for large-scale deployment of the current perovskite solar materials is the use of Pb to achieve high power conversion efficiency. While this appears to be a technical issue, there are more fundamental reasons behind. The current research has mainly focused on the replacement of Pb by other elements, in particular, Sn. However, in halide perovskites (i.e., I-II-VII3 composition), Sn is in its less stable 2 + state. The formation of more stable 4 + centers in the Sn(II)-based materials under ambient conditions makes the device efficiency very low. Worse, there might be no other elements across the Periodic Table that can replace Pb while maintaining the desirable properties, such as band gap. Out-of-the-box ideas are therefore called for to stimulate the research in this field. In this talk, two approaches are proposed based on state-of-the-art first-principles calculations. Through a screening of chalcogenide perovskite materials, CaTiS3, BaZrS3, CaZrSe3, and CaHfSe3 have been predicted to have suitable band gaps for making solar cells. Among these materials, BaZrS3 have been synthesized experimentally. Another proposed approach is to introduce dual anions (i.e., splitting the anion sites) that allow the composition to satisfy charge neutrality, while replacing Pb by more environmentally benign elements. One of the candidate materials is CH3NH3BiSI2, which is predicted to have band gap around 1.4 eV and high optical absorption.

  14. 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.

  15. Lead-free Mn-doped (K0.5,Na0.5)NbO3 piezoelectric thin films for MEMS-based vibrational energy harvester applications

    NASA Astrophysics Data System (ADS)

    Won, Sung Sik; Lee, Joonhee; Venugopal, Vineeth; Kim, Dong-Joo; Lee, Jinkee; Kim, Ill Won; Kingon, Angus I.; Kim, Seung-Hyun

    2016-06-01

    Lead-free Mn-doped (K0.5, Na0.5)NbO3 (KNN) thin films were fabricated by the chemical solution deposition method. The addition of small concentration of Mn dopant effectively reduced the leakage current density and enhanced the piezoelectric properties of the films. The leakage current density of 0.5 mol. % Mn-doped KNN film showed the lowest value of ˜10-7 A/cm2 at 10 V compared to the films with other doping concentrations and the piezoelectric d33 and e31 coefficients of this film were ˜90 pm/V and -8.5 C/m2, respectively. The maximum power and power density of the lead-free thin film-based vibrational energy harvesting device were 3.62 μW and 1800 μW/cm3 at the resonance frequency of 132 Hz and the acceleration of 1.0 G. The results prove that the 0.5 mol. % Mn-doped KNN film is an attractive candidate transducer layer for the piezoelectric MEMS energy harvesting device applications with a small volume and a long-lasting power source.

  16. 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.

  17. Enhanced piezoelectricity and photoluminescence in Dy-doped Ba0.85Ca0.15Ti0.9Zr0.1O3 lead-free multifunctional ceramics

    NASA Astrophysics Data System (ADS)

    Lei, Fengying; Jiang, Na; Luo, Lingling; Guo, Yongquan; Zheng, Qiaoji; Lin, Dunmin

    2015-12-01

    Lead-free multifunctional ceramics of Ba0.85Ca0.15Ti0.9Zr0.1O3-x mol% Dy have been prepared by an ordinary sintering method and the effects of Dy2O3 doping on structure, piezoelectric, ferroelectric and photoluminescent properties of the ceramics have been studied. The ceramics possess a single phase perovskite structure. The grain growth of the ceramics is prohibited and the ferroelectric-paraelectric phase transition at TC becomes more diffusive after the addition of Dy2O3. Dy2O3 doping improves the piezoelectricity of the ceramics and the optimal piezoelectric properties d33 = 335 pC/N is obtained at x = 0.5. The addition of 2 mol% Dy enhances the photoluminescent properties of the ceramics and strong emissions at ˜ 478 nm and ˜ 575 nm are observed. Our study shows that the ceramics with low Dy2O3 levels exhibit simultaneously the strong piezoelectricity, ferroelectricity and photoluminescence and may have a potential application in mechano-electro-optic integration and coupling device.

  18. Lead-free intravascular ultrasound transducer using BZT-50BCT ceramics.

    PubMed

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

    2013-06-01

    This paper reports the fabrication and evaluation of a high-frequency ultrasonic transducer based on a new lead-free piezoelectric material for intravascular imaging application. Lead-free 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO4(BZT-50BCT) ceramic with a high dielectric constant (~2800) was employed to develop a high-frequency (~30 MHz) needle-type ultrasonic transducer. With superior piezoelectric performance (piezoelectric coefficient d33 ~ 600 pC/N), the lead-free transducer was found to exhibit a -6-dB bandwidth of 53% with an insertion loss of 18.7 dB. In vitro intravascular ultrasound (IVUS) imaging of a human cadaver coronary artery was performed to demonstrate the potential of the lead-free transducer for biomedical imaging applications. This is the first time that a lead-free transducer has been used for IVUS imaging application. The experimental results suggest that the BZT-50BCT ceramic is a promising lead-free piezoelectric material for high-frequency intravascular imaging applications. PMID:25004492

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

    PubMed Central

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

    2013-01-01

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

  20. Fabrication and characterization of Na0.5K0.5NbO3-CuNb2O6 lead-free step-down piezoelectric transformers

    NASA Astrophysics Data System (ADS)

    Yang, Ming-Ru; Chu, Sheng-Yuan; Chan, I.-Hao; Huang, Sheng-Kai

    2011-08-01

    Lead-free (Na0.5K0.5)NbO3 (NKN) ceramics doped with 1 mol% CuNb2O6 (01CN) ceramics were prepared using the conventional mixed oxide method at a sintering temperature of 1075 °C. NKN + 1 mol% CuTa2O6 (NKN-01CN) ceramics sintered at 1075 °C exhibit excellent "hard" piezoelectric properties of kp = 40%, kt = 45%, and k33 = 57%, with ferroelectric property Ec = 23 kV/cm. The mechanical quality factor (Qm) is extraordinarily high (1933) and the temperature stability is excellent (Temperature coefficient of frequency (TCF) = -154 ppm/°C). The piezoelectric transformer (PT) was fabricated on NKN-01CN lead-free substrates, and the electrical characteristics were investigated. The devices were simplified into an equivalent circuit and analyzed using the MATLAB software package. The simulation results matched the experimental results. By reversing the input and the output, the step-down PT can be easily fabricated using a simple disk-type structure. A maximum efficiency of 93% with a voltage gain of 0.12 was measured, which was in good agreement with the simulation results (a maximum efficiency of 98.7% with a voltage gain of 0.13) for the step-down mode.

  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. Innovations in piezoelectric materials for ultrasound transducers

    NASA Astrophysics Data System (ADS)

    Shrout, Thomas R.; Park, Seung Eek E.; Lopath, Patrick D.; Meyer, Richard J., Jr.; Ritter, Timothy A.; Shung, K. Kirk

    1998-05-01

    Piezoelectric material lie at the heart of ultrasonic transducers. Recent advances in materials development include submicron piezoelectric ceramics (PZT) which lead to improvements in feature size, i.e. aspect ratio, element width, etc., for linear arrays and high frequency transducers. In contrast to fine grain ceramics, single crystal materials based on Relaxor-PT ferroelectrics offer electromechanical coupling coefficients > 90 percent with a range of dielectric permittivity allowing flexibility in transducer engineering in regard to electrical impedance matching. Using KLM modeling, very high bandwidth performance > 120 percent is projected. Specific examples of high frequency 1-3 composites and 1D linear array transducers fabricated from new piezoelectric materials, including sol-gel derived PZT fibers, are presented.

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

    SciTech Connect

    Chen, Y.Q.; Zheng, X.J.; Feng, X.; Dai, S.H.; Zhang, D.Z.

    2010-06-15

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

  4. Dielectric, ferroelectric, and piezoelectric properties of the lead-free (1-x)(Na0.5Bi0.5)TiO3-xBiAlO3 solid solution

    NASA Astrophysics Data System (ADS)

    Yu, Huichun; Ye, Zuo-Guang

    2008-09-01

    Lead-free piezoelectric ceramics derived from the solid solution of (1-x)(Na0.5Bi0.5)TiO3-xBiAlO3 (NBT-BA) (x =0-0.10) have been synthesized by solid state reactions. A pure perovskite phase was formed for x ≤0.08. The temperature dependence of dielectric constant indicates an increased broadness of the dielectric peak as the amount of BA increases. The large dielectric loss of NBT ceramics at low frequency and high temperature has been significantly reduced by the substitution of BA. The high coercive field is decreased and ferroelectric hysteresis loops were displayed at room temperature. The NBT-BA ceramics exhibit improved ferroelectric and piezoelectric properties compared to pure NBT ceramics, with Pr=52 μC/cm2, Ec=44 kV/cm, d33=130 pC/N, and kp=0.23 for 0.92NBT-0.08BA.

  5. Lead-free piezoelectric system (Na0.5Bi0.5)TiO3-BaTiO3: Equilibrium structures and irreversible structural transformations driven by electric field and mechanical impact

    NASA Astrophysics Data System (ADS)

    Garg, Rohini; Rao, Badari Narayana; Senyshyn, Anatoliy; Krishna, P. S. R.; Ranjan, Rajeev

    2013-07-01

    The structure-property correlation in the lead-free piezoelectric (1-x)(Na0.5Bi0.5)TiO3-(x)BaTiO3 has been systematically investigated in detail as a function of composition (0piezoelectric measurement, x-ray, and neutron powder diffraction methods. Although x-ray diffraction study revealed three distinct composition ranges characterizing different structural features in the equilibrium state at room temperature: (i) monoclinic (Cc)+rhombohedral (R3c) for the precritical compositions, 0≤x≤0.05, (ii) cubiclike for 0.06≤x≤0.0675, and (iii) morphotropic phase boundary (MPB) like for 0.07≤x<0.10, Raman and neutron powder diffraction studies revealed identical symmetry for the cubiclike and the MPB compositions. The cubiclike structure undergoes irreversible phase separation by electric poling as well as by pure mechanical impact. This cubiclike phase exhibits relaxor ferroelectricity in its equilibrium state. The short coherence length (˜50 Å) of the out-of-phase octahedral tilts does not allow the normal ferroelectric state to develop below the dipolar freezing temperature, forcing the system to remain in a dipolar glass state at room temperature. Electric poling helps the dipolar glass state to transform to a normal ferroelectric state with a concomitant enhancement in the correlation length of the out-of-phase octahedral tilt.

  6. Elastomer degradation sensor using a piezoelectric material

    DOEpatents

    Olness, Dolores U.; Hirschfeld, deceased, Tomas B.

    1990-01-01

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

  7. 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.

  8. 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.

  9. Magnetoelectric coupling in lead-free piezoelectric Lix(K0.5Na0.5)1 - xNb1 - yTayO3 and magnetostrictive CoFe2O4 laminated composites

    NASA Astrophysics Data System (ADS)

    Fu, Jiyong; Santa Rosa, Washington; M'Peko, Jean Claude; Algueró, Miguel; Venet, Michel

    2016-04-01

    To replace lead zirconium titanate in magnetoelectric (ME) composites owing to concerns regarding its toxicity, we investigate the ME coupling in bilayer composites comprising lead-free Lix(K0.5Na0.5)1 - xNb1 - yTayO3 (LKNNT) (piezoelectric) and CoFe2O4 (magnetostrictive) phases. We prepare the LKNNT ceramics and measure its piezoelectric coefficient d31, a crucial ingredient determining ME couplings, for several Li (x = 0.03 , 0.035 , 0.04) and Ta (y = 0.15 , 0.2 , 0.25) concentrations, and find that the highest d31 occurs at y = 0.2 for all the values of x studied here. We then evaluate both the transverse (αE,31) and the longitudinal (αE,33) low-frequency ME coupling coefficients of our composites, for each the above composition of (x , y). At x = 0.03, we find the usual scenario of αE,31 and αE,33, i.e., the strongest ME coupling occurs when d31 is maximal, namely at y = 0.2. On the other hand, interestingly, we also obtain the strongest ME coupling when the LKNNT layer has a relatively weaker d31, e.g., at y = 0.25 for x = 0.035 and y = 0.15 for x = 0.04, following from the interplay of d31 and other ingredients (e.g., dielectric constant). Our calculated ME couplings, with αE,31 in magnitude around twice of αE,33, are comparable to those in lead-based composites. The effect of the volume fraction and interface parameter on the ME coupling is also discussed.

  10. Structure, ferroelectric and piezoelectric properties of (Bi0.98- x La0.02Na1- x )0.5Ba x TiO3 lead-free ceramics

    NASA Astrophysics Data System (ADS)

    Lin, Dunmin; Kwok, K. W.

    2009-10-01

    Lead-free (Bi0.98- x La0.02Na1- x )0.5Ba x TiO3 ceramics have been prepared by an ordinary sintering technique and their structure, ferroelectric and piezoelectric properties have been studied. The results of X-ray diffraction show that La2+ and Ba2+ diffuse into the Bi0.5Na0.5TiO3 lattices to form a new solid solution with a pure perovskite structure, and a morphotropic phase boundary (MPB) exists at 0.04< x<0.10. Compared with pure Bi0.5Na0.5TiO3 ceramics, the (Bi0.98- x La0.02Na1- x )0.5Ba x TiO3 ceramics possess much smaller coercive field E c and larger remanent polarization P r. Because of the low E c (3.38 kV/mm), large P r (46.2 μC/cm2) and the formation of the MPB of rhombohedral and tetragonal phases, the piezoelectric properties of the ceramics are significantly enhanced at x=0.06: d 33=181 pC/N and k p=36.3%. The depolarization temperature T d reaches a minimum value near the MPB. The ceramics exhibit relaxor characteristic, which is probably a result from the cation disordering in the 12-fold coordination sites. The temperature dependences of the ferroelectric and dielectric properties suggest that the ceramics may contain both polar and non-polar regions at the temperatures above T d.

  11. 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

  12. 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.

  13. Structural crossover from nonmodulated to long-period modulated tetragonal phase and anomalous change in ferroelectric properties in the lead-free piezoelectric N a1 /2B i1 /2Ti O3-BaTi O3

    NASA Astrophysics Data System (ADS)

    Rao, Badari Narayana; Khatua, Dipak Kumar; Garg, Rohini; Senyshyn, Anatoliy; Ranjan, Rajeev

    2015-06-01

    The highly complex structure-property interrelationship in the lead-free piezoelectric (x )N a1 /2B i1 /2Ti O3- (1 -x ) BaTi O3 is a subject of considerable contemporary debate. Using comprehensive x-ray, neutron diffraction, dielectric, and ferroelectric studies, we have shown the existence of a new criticality in this system at x =0.80 , i.e., well within the conventional tetragonal phase field. This criticality manifests as a nonmonotonic variation of the tetragonality and coercivity and is shown to be associated with a crossover from a nonmodulated tetragonal phase (for x <0.8 ) to a long-period modulated tetragonal phase (for x >0.80 ). It is shown that the stabilization of long-period modulation introduces a characteristic depolarization temperature in the system. While differing qualitatively from the two-phase model often suggested for the critical compositions of this system, our results support the view with regard to the tendency in perovskites to stabilize long-period modulated structures as a result of complex interplay of antiferrodistortive modes [Bellaiche and Iniguez, Phys. Rev. B 88, 014104 (2013), 10.1103/PhysRevB.88.014104; Prosandeev, Wang, Ren, Iniguez, ands Bellaiche, Adv. Funct. Mater. 23, 234 (2013), 10.1002/adfm.201201467].

  14. Microstructure, dielectric and piezoelectric properties of (K0.5Na0.5)NbO3-Ba(Ti0.95Zr0.05)O3 lead-free ceramics with CuO sintering aid

    NASA Astrophysics Data System (ADS)

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

    2007-08-01

    Using an ordinary ceramic fabrication technique, we fabricated lead-free (1-x)(K0.5Na0.5)NbO3-xBa(Ti0.95Zr0.05)O3 ceramics with CuO sintering aid . Ba(Ti0.95Zr0.05)O3 diffuses into (K0.5Na0.5)NbO3 to form a new solid solution. The ceramics with perovskite structure possess orthorhombic phase at x≤0.04 and become tetragonal phase at x≥0.06. Both the paraelectric cubic-ferroelectric tetragonal and the ferroelectric tetragonal-ferroelectric orthorhombic phase transition temperatures decrease with increasing the concentration of Ba(Ti0.95Zr0.05)O3. The doping of CuO effectively promotes the densification of the ceramics. The coexistence of the orthorhombic and tetragonal phases at 0.04piezoelectric and dielectric properties at room temperature. The ceramics with x=0.04-0.06 and y=0.75-1.50 possess excellent properties: d33=119-185 pC/N, kP=37-44%, kt=35-49%, ɛ=341-1129, cosδ=0.7-4.4% and Tc=312-346 °C.

  15. Phase structure and piezoelectric properties of (1-x)K0.48Na0.52Nb0.95Sb0.05O3-x(Bi0.5Na0.5)0.9(Li0.5Ce0.5)0.1ZrO3 lead-free piezoelectric ceramics

    NASA Astrophysics Data System (ADS)

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

    2016-01-01

    (1-x)K0.48Na0.52Nb0.95Sb0.05O3-x(Bi0.5Na0.5)0.9(Li0.5Ce0.5)0.1ZrO3 [(1-x)KNNS-xBNLCZ] lead-free piezoceramics were prepared by the conventional solid state sintering method. The effects of BNLCZ contents on their phase structure, microstructure, and piezoelectric properties were investigated. All the samples show a pure perovskite structure, and no secondary phases were formed in the detected range. The rhombohedral and tetragonal phases of (1-x)KNNS-xBNLCZ coexist in the composition range of 0.0325 ≤ x ≤ 0.0425 at room temperature. A remarkably strong piezoelectricity was obtained by the addition of appropriate BNLCZ contents. The excellent piezoelectric properties of the ceramics with x = 0.04 were obtained: d33 ˜ 485 pC/N, kp ˜ 48%, and TC ˜ 227 °C. All the results show that the introduction of (Bi0.5Na0.5)0.9(Li0.5Ce0.5)0.1ZrO3 is a very effective way to form the rhombohedral and tetragonal phase coexistence of potassium-sodium niobate-based ceramics, which can improve its piezoelectric properties.

  16. Integration of bulk piezoelectric materials into microsystems

    NASA Astrophysics Data System (ADS)

    Aktakka, Ethem Erkan

    Bulk piezoelectric ceramics, compared to deposited piezoelectric thin-films, provide greater electromechanical coupling and charge capacity, which are highly desirable in many MEMS applications. In this thesis, a technology platform is developed for wafer-level integration of bulk piezoelectric substrates on silicon, with a final film thickness of 5-100microm. The characterized processes include reliable low-temperature (200°C) AuIn diffusion bonding and parylene bonding of bulk-PZT on silicon, wafer-level lapping of bulk-PZT with high-uniformity (+/-0.5microm), and low-damage micro-machining of PZT films via dicing-saw patterning, laser ablation, and wet-etching. Preservation of ferroelectric and piezoelectric properties is confirmed with hysteresis and piezo-response measurements. The introduced technology offers higher material quality and unique advantages in fabrication flexibility over existing piezoelectric film deposition methods. In order to confirm the preserved bulk properties in the final film, diaphragm and cantilever beam actuators operating in the transverse-mode are designed, fabricated and tested. The diaphragm structure and electrode shapes/sizes are optimized for maximum deflection through finite-element simulations. During tests of fabricated devices, greater than 12microm PP displacement is obtained by actuation of a 1mm2 diaphragm at 111kHz with <7mW power consumption. The close match between test data and simulation results suggests that the piezoelectric properties of bulk-PZT5A are mostly preserved without any necessity of repolarization. Three generations of resonant vibration energy harvesters are designed, simulated and fabricated to demonstrate the competitive performance of the new fabrication process over traditional piezoelectric deposition systems. An unpackaged PZT/Si unimorph harvester with 27mm3 active device volume produces up to 205microW at 1.5g/154Hz. The prototypes have achieved the highest figure-of-merits (normalized

  17. Sintering, microstructure and electrical properties of 0.4(Bi0.5K0.5)TiO3-0.6BiFeO3 lead-free piezoelectric ceramics

    NASA Astrophysics Data System (ADS)

    Fisher, John G.; Park, Ha-Young; Song, Yeo-Ok; Baek, Sun-Joong; Vu, Hung; Kim, Jee-Hoon; Kim, Young-Hun; Lee, Jong Sook

    2016-01-01

    The effect of sintering temperature on the densification, microstructure and structure of 0.4(Bi0.5K0.5)TiO3-0.6BiFeO3 lead-free piezoelectric ceramics is assessed. The 0.4(Bi0.5K0.5)TiO3-0.6BiFeO3 powders were prepared by using the mixed-oxide method and were sintered at temperatures of 1000, 1050 and 1100 °C for 1 to 5 hrs. Unlike earlier work, the sintered samples showed high densities even when sintered at 1000 °C. X-ray diffraction revealed that the sintered samples shared the same rhombohedral structure as BiFeO3. With increasing sintering temperature, the rhombohedral distortion of the unit cell decreased. In addition to the relaxor-like broad peak around 400 °C, a low-temperature dielectric peak was found at temperatures below 190 °C by employing a low-frequency sweep down to 10 mHz. The DC conductivity of the 0.4(Bi0.5K0.5)TiO3-0.6BiFeO3 sample exhibited three temperature regions with activation energy values of 0.56 eV (T > 500°C), 0.72 eV (400°C < T <200°C) and 0.81 eV (T < 190°C). The characteristic transitions in the conductivity could be related to the Néel temperature (370°C) and the conductivity anomaly observed at ca. 190°C in BiFeO3.

  18. Effect of material uncertainties on dynamic analysis of piezoelectric fans

    NASA Astrophysics Data System (ADS)

    Srivastava, Swapnil; Yadav, Shubham Kumar; Mukherjee, Sujoy

    2015-04-01

    A piezofan is a resonant device that uses a piezoceramic material to induce oscillations in a cantilever beam. In this study, lumped-mass modelling is used to analyze a piezoelectric fan. Uncertainties are associated with the piezoelectric structures due to several reasons such as variation during manufacturing process, temperature, presence of adhesive layer between the piezoelectric actuator/sensor and the shim stock etc. Presence of uncertainty in the piezoelectric materials can influence the dynamic behavior of the piezoelectric fan such as natural frequency, tip deflection etc. Moreover, these quantities will also affect the performance parameters of the piezoelectric fan. Uncertainty analysis is performed using classical Monte Carlo Simulation (MCS). It is found that the propagation of uncertainty causes significant deviations from the baseline deterministic predictions, which also affect the achievable performance of the piezofan. The numerical results in this paper provide useful bounds on several performance parameters of the cooling fan and will enhance confidence in the design process.

  19. 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.

  20. Energy harvesting from low frequency applications using piezoelectric materials

    SciTech Connect

    Li, Huidong; Tian, Chuan; Deng, Z. Daniel

    2014-12-15

    In an effort to eliminate the replacement of the batteries of electronic devices that are difficult or impractical to service once deployed, harvesting energy from mechanical vibrations or impacts using piezoelectric materials has been researched over the last several decades. However, a majority of these applications have very low input frequencies. This presents a challenge for the researchers to optimize the energy output of piezoelectric energy harvesters, due to the relatively high elastic moduli of piezoelectric materials used to date. This paper reviews the current state of research on piezoelectric energy harvesting devices for low frequency (0–100 Hz) applications and the methods that have been developed to improve the power outputs of the piezoelectric energy harvesters. Various key aspects that contribute to the overall performance of a piezoelectric energy harvester are discussed, including geometries of the piezoelectric element, types of piezoelectric material used, techniques employed to match the resonance frequency of the piezoelectric element to input frequency of the host structure, and electronic circuits specifically designed for energy harvesters.

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

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

  2. System and Method for Monitoring Piezoelectric Material Performance

    NASA Technical Reports Server (NTRS)

    Moses, Robert W. (Inventor); Fox, Christopher L. (Inventor); Fox, Melanie L. (Inventor); Chattin, Richard L. (Inventor); Shams, Qamar A. (Inventor); Fox, Robert L. (Inventor)

    2007-01-01

    A system and method are provided for monitoring performance capacity of a piezoelectric material that may form part of an actuator or sensor device. A switch is used to selectively electrically couple an inductor to the piezoelectric material to form an inductor-capacitor circuit. Resonance is induced in the inductor-capacitor circuit when the switch is operated to create the circuit. The resonance of the inductor-capacitor circuit is monitored with the frequency of the resonance being indicative of performance capacity of the device's piezoelectric material.

  3. High-frequency ultrasonic transducer based on lead-free BSZT piezoceramics.

    PubMed

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

    2011-10-01

    This paper describes the fabrication and evaluation of a high-frequency (40MHz) transducer based on lead-free piezoceramics for ultrasonic imaging. The transducer with an aperture size of 0.9mm has been fabricated using barium strontium zirconate titanate ((Ba(0.95)Sr(0.05))(Zr(0.05)Ti(0.95))O(3), abbreviated as BSZT) ceramics. The lead-free BSZT has a piezoelectric d(33) coefficient of 300 pC/N and an electromechanical coupling factor k(t) of 0.45. High-frequency ultrasound transducers were fabricated and a bandwidth of 76.4% has been achieved with an insertion loss of -26dB. Applications in high resolution biological and medical imaging could be possible with this lead-free material. PMID:21477833

  4. Piezoelectric Ignition of Nanocomposite Energetic Materials

    SciTech Connect

    Eric Collins; Michelle Pantoya; Andreas A. Neuber; Michael Daniels; Daniel Prentice

    2014-01-01

    Piezoelectric initiators are a unique form of ignition for energetic material because the current and voltage are tied together by impact loading on the crystal. This study examines the ignition response of an energetic composite composed of aluminum and molybdenum trioxide nanopowders to the arc generated from a lead zirconate and lead titanate piezocrystal. The mechanical stimuli used to activate the piezocrystal varied to assess ignition voltage, power, and delay time of aluminum–molybdenum trioxide for a range of bulk powder densities. Results show a high dielectric strength leads to faster ignition times because of the higher voltage delivered to the energetic. Ignition delay is under 0.4 ms, which is faster than observed with thermal or shock ignition. Electric ignition of composite energetic materials is a strong function of interparticle connectivity, and thus the role of bulk density on electrostatic discharge ignition sensitivity is a focus of this study. Results show that the ignition delay times are dependent on the powder bulk density with an optimum bulk density of 50%. Packing fractions and electrical conductivity were analyzed and aid in explaining the resulting ignition behavior as a function of bulk density.

  5. Lead-free electric matches.

    SciTech Connect

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

    2002-01-01

    Electric matches are used in pyrotechnics to initiate devices electrically rather than by burning fuses. Fuses have the disadvantage of burning with a long delay before igniting a pyrotechnic device, while electric matches can instantaneously fire a device at a user's command. In addition, electric matches can be fired remotely at a safe distance. Unfortunately, most current commercial electric match compositions contain lead as thiocyanate, nitroresorcinate or tetroxide, which when burned, produces lead-containing smoke. This lead pollutant presents environmental exposure problems to cast, crew, and audience. The reason that these lead containing compounds are used as electric match compositions is that these mixtures have the required thermal stability, yet are simultaneously able to be initiated reliably by a very small thermal stimulus. A possible alternative to lead-containing compounds is nanoscale thermite materials (metastable intermolecular composites or MIC). These superthermite materials can be formulated to be extremely spark sensitive with tunable reaction rate and yield high temperature products. We have formulated and manufactured lead-free electric matches based on nanoscale Al/MoO{sub 3} mixtures. We have determined that these matches fire reliably and to consistently ignite a sample of black powder. Initial safety, ageing and performance results are presented in this paper.

  6. 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.

  7. Properties of (Bi0.5Na0.5)TiO3-BaTiO3-(Bi0.5Na0.5)(Mn1/3Nb2/3)O3 Lead-Free Piezoelectric Ceramics and Its Application to Ultrasonic Cleaner

    NASA Astrophysics Data System (ADS)

    Tou, Tonshaku; Hamaguti, Yuki; Maida, Yuichi; Yamamori, Haruo; Takahashi, Kazutoshi; Terashima, Yoshimitsu

    2009-07-01

    The lead-free piezoelectric ceramics 0.82(Bi0.5Na0.5)TiO3-0.15BaTiO3-0.03(Bi0.5Na0.5)(Mn1/3Nb2/3)O3 (abbreviated as BNT-BT-BNMN) was prepared by a conventional process of ceramic engineering. The X-ray diffractometer (XRD) analysis showed that all compositions could form a single perovskite phase. The ceramics showed excellent piezoelectric properties with a coupling factor kt=41%, a mechanical quality factor Qm=500, a piezoelectric constant d33=110 pC/N, a relative permittivity ɛ33T/ɛ0=520, a dissipation factor tan δ=0.66%, a Curie point Tc=260 °C, and a density ρ=5.5 g/cm3. The physical properties of the ceramics were superior to those of hard Pb(Zr,Ti)O3 (PZT). The high-power characteristics of the ceramics were superior to those of hard PZT. A cylinder sample of lead-free ceramics was used to fabricate a bolt-clamped Langevin transducer (BLT) for application in the ultrasonic cleaner. The vibration velocity of BLT using the ceramics was higher than that of hard PZT under the same input power. The cleaning effect of an ultrasonic cleaner using the BLTs was very high and sufficiently good for commercial application.

  8. Lead-free ternary perovskite compounds with large electromechanical strains

    NASA Astrophysics Data System (ADS)

    Jarupoom, Parkpoom; Patterson, Eric; Gibbons, Brady; Rujijanagul, Gobwute; Yimnirun, Rattikorn; Cann, David

    2011-10-01

    Lead-free compounds based on perovskite solid solutions in the ternary system (Bi1/2Na1/2)TiO3-(Bi1/2K1/2)TiO3-Bi(X1/2Ti1/2)O3, where X = Ni and Mg have been shown to exhibit large electromechanical strains. While the perovskite end members Bi(Mg1/2Ti1/2)O3 and Bi(Ni1/2Ti1/2)O3 display limited stability in their pure state, both compounds were found to have solid solubilities of at least 50 mol. % with (Bi1/2Na1/2)TiO3 and (Bi1/2K1/2)TiO3. Most importantly, under relatively large applied fields, these materials exhibited large hysteretic electromechanical strains characterized by a parabolic shape. With effective piezoelectric coefficients (d33*) greater than 500 pm/V, these systems have excellent potential as a Pb-free piezoelectric materials.

  9. Parylene-C as a New Piezoelectric Material

    NASA Astrophysics Data System (ADS)

    Kim, Justin Young-Hyun

    The goal of this thesis is to develop a proper microelectromechanical systems (MEMS) process to manufacture piezoelectric Parylene-C (PA-C), which is famous for its chemical inertness, mechanical and thermal properties and electrical insulation. Furthermore, piezoelectric PA-C is used to build miniature, inexpensive, non-biased piezoelectric microphones. These piezoelectric PA-C MEMS microphones are to be used in any application where a conventional piezoelectric and electret microphone can be used, such as in cell phones and hearing aids. However, they have the advantage of a simplified fabrication process compared with existing technology. In addition, as a piezoelectric polymer, PA-C has varieties of applications due to its low dielectric constant, low elastic stiffness, low density, high voltage sensitivity, high temperature stability and low acoustic and mechanical impedance. Furthermore, PA-C is an FDA approved biocompatible material and is able to maintain operate at a high temperature. To accomplish piezoelectric PA-C, a MEMS-compatible poling technology has been developed. The PA-C film is poled by applying electrical field during heating. The piezoelectric coefficient, -3.75pC/N, is obtained without film stretching. The millimeter-scale piezoelectric PA-C microphone is fabricated with an in-plane spiral arrangement of two electrodes. The dynamic range is from less than 30 dB to above 110 dB SPL (referenced 20 microPa) and the open-circuit sensitivities are from 0.001 - 0.11 mV/Pa over a frequency range of 1 - 10 kHz. The total harmonic distortion of the device is less than 20% at 110 dB SPL and 1 kHz.

  10. 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.

  11. High Pressure Hydrogen Materials Compatibility of Piezoelectric Films

    SciTech Connect

    Alvine, Kyle J.; Shutthanandan, V.; Bennett, Wendy D.; Bonham, Charles C.; Skorski, Daniel C.; Pitman, Stan G.; Dahl, Michael E.; Henager, Charles H.

    2010-12-02

    Abstract: Hydrogen is being considered as a next-generation clean burning fuel. However, hydrogen has well known materials issues, including blistering and embrittlement in metals. Piezoelectric materials are used as actuators in hydrogen fuel technology. We present studies of materials compatibility of piezoelectric films in a high pressure hydrogen environment. Absorption of high pressure hydrogen was studied with Elastic Recoil Detection Analysis (ERDA) and Rutherford Back Scattering (RBS) in lead zirconate titanate (PZT) and barium titanate (BTO) thin films. Hydrogen surface degradation in the form of blistering and Pb mixing was also observed.

  12. 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.

  13. 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.

  14. Breakthrough: Lead-free Solder

    ScienceCinema

    Anderson, Iver

    2013-03-01

    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.

  15. A database to enable discovery and design of piezoelectric materials

    PubMed Central

    de Jong, Maarten; Chen, Wei; Geerlings, Henry; Asta, Mark; Persson, Kristin Aslaug

    2015-01-01

    Piezoelectric materials are used in numerous applications requiring a coupling between electrical fields and mechanical strain. Despite the technological importance of this class of materials, for only a small fraction of all inorganic compounds which display compatible crystallographic symmetry, has piezoelectricity been characterized experimentally or computationally. In this work we employ first-principles calculations based on density functional perturbation theory to compute the piezoelectric tensors for nearly a thousand compounds, thereby increasing the available data for this property by more than an order of magnitude. The results are compared to select experimental data to establish the accuracy of the calculated properties. The details of the calculations are also presented, along with a description of the format of the database developed to make these computational results publicly available. In addition, the ways in which the database can be accessed and applied in materials development efforts are described. PMID:26451252

  16. A Resonant Damping Study Using Piezoelectric Materials

    NASA Technical Reports Server (NTRS)

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

    2008-01-01

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

  17. Hierarchical domain structure of lead-free piezoelectric (Na1/2 Bi1/2)TiO3-(K1/2 Bi1/2)TiO3 single crystals

    NASA Astrophysics Data System (ADS)

    Luo, Chengtao; Wang, Yaojin; Ge, Wenwei; Li, Jiefang; Viehland, Dwight; Delaire, Olivier; Li, Xiaobin; Luo, Haosu

    2016-05-01

    We report a unique hierarchical domain structure in single crystals of (Na1/2Bi1/2)TiO3-xat. %(K1/2Bi1/2)TiO3 for x = 5 and 8 by transmission electron microscopy (TEM). A high density of polar nano-domains with a lamellar morphology was found, which were self-assembled into a quadrant-like configuration, which then assembled into conventional ferroelectric macro-domains. Studies by high resolution TEM revealed that the polar lamellar regions contained a coexistence of in-phase and anti-phase oxygen octahedral tilt regions of a few nanometers in size. Domain frustration over multiple length scales may play an important role in the stabilization of the hierarchy, and in reducing the piezoelectric response of this Pb-free piezoelectric solid solution.

  18. Cellulose Nanofibril Film as a Piezoelectric Sensor Material.

    PubMed

    Rajala, Satu; Siponkoski, Tuomo; Sarlin, Essi; Mettänen, Marja; Vuoriluoto, Maija; Pammo, Arno; Juuti, Jari; Rojas, Orlando J; Franssila, Sami; Tuukkanen, Sampo

    2016-06-22

    Self-standing films (45 μm thick) of native cellulose nanofibrils (CNFs) were synthesized and characterized for their piezoelectric response. The surface and the microstructure of the films were evaluated with image-based analysis and scanning electron microscopy (SEM). The measured dielectric properties of the films at 1 kHz and 9.97 GHz indicated a relative permittivity of 3.47 and 3.38 and loss tangent tan δ of 0.011 and 0.071, respectively. The films were used as functional sensing layers in piezoelectric sensors with corresponding sensitivities of 4.7-6.4 pC/N in ambient conditions. This piezoelectric response is expected to increase remarkably upon film polarization resulting from the alignment of the cellulose crystalline regions in the film. The CNF sensor characteristics were compared with those of polyvinylidene fluoride (PVDF) as reference piezoelectric polymer. Overall, the results suggest that CNF is a suitable precursor material for disposable piezoelectric sensors, actuators, or energy generators with potential applications in the fields of electronics, sensors, and biomedical diagnostics. PMID:27232271

  19. 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.

  20. Piezoelectric properties of rhombohedral ferroelectric materials with phase transition

    NASA Astrophysics Data System (ADS)

    Zhao, Xiaofang; Soh, A. K.

    2015-12-01

    The temporal evolution of domain structure and its piezoelectric behavior of ferroelectric material BaTiO3 during the transition process from rhombohedral to tetragonal phase under an applied electric field have been studied by employing Landau-Ginzburg theory and the phase-field method. The results obtained show that, during the transformation process, the intermediate phase was monoclinic MA phase, and several peak values of piezoelectric coefficient appeared at the stage where obvious change of domain pattern occurred. In addition, by comparing the cases of applied electric field with different frequencies, it was found that the maximum piezoelectric coefficient obtained decreased with increasing frequency value. These results are of great significance in tuning the properties of engineering domains in ferroelectrics, and could provide more fundamentals to the design of ferroelectric devices.

  1. Novel composite piezoelectric material for energy harvesting applications

    NASA Astrophysics Data System (ADS)

    Janusas, Giedrius; Guobiene, Asta; Palevicius, Arvydas; Prosycevas, Igoris; Ponelyte, Sigita; Baltrusaitis, Valentinas; Sakalys, Rokas

    2015-04-01

    Past few decades were concentrated on researches related to effective energy harvesting applied in modern technologies, MEMS or MOEMS systems. There are many methods for harvesting energy as, for example, usage of electromagnetic devices, but most dramatic changes were noticed in the usage of piezoelectric materials in small scale devices. Major limitation faced was too small generated power by piezoelectric materials or high resonant frequencies of such smallscale harvesters. In this research, novel composite piezoelectric material was created by mixing PZT powder with 20% solution of polyvinyl butyral in benzyl alcohol. Obtained paste was screen printed on copper foil using 325 mesh stainless steel screen and dried for 30 min at 100 °C. Polyvinyl butyral ensures good adhesion and flexibility of a new material at the conditions that requires strong binding. Five types of a composite piezoelectric material with different concentrations of PZT (40%, 50%, 60%, 70% and 80 %) were produced. As the results showed, these harvesters were able to transform mechanical strain energy into electric potential and, v.v. In experimental setup, electromagnetic shaker was used to excite energy harvester that is fixed in the custom-built clamp, while generated electric potential were registered with USB oscilloscope PICO 3424. The designed devices generate up to 80 μV at 50 Hz excitation. This property can be applied to power microsystem devices or to use them in portable electronics and wireless sensors. However, the main advantage of the created composite piezoelectric material is possibility to apply it on any uniform or nonuniform vibrating surface and to transform low frequency vibrations into electricity.

  2. 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.

  3. Piezoelectric properties of (K0.5Na0.5)NbO3-BaTiO3 lead-free ceramics prepared by spark plasma sintering

    NASA Astrophysics Data System (ADS)

    Men, Tian-Lu; Yao, Fang-Zhou; Zhu, Zhi-Xiang; Wang, Ke; Li, Jing-Feng

    2016-07-01

    (K,Na)NbO3 (KNN)-based lead-free piezoceramics have been the spotlight in search for practically viable candidates to replace the hazardous but dominating lead-containing counterparts. In this work, BaTiO3 (BT) modified KNN ceramics were fabricated by spark plasma sintering (SPS) and the influence of BT content as well as sintering temperature on the phase structure, microstructure, and electrical properties were investigated. It was found that the 0.96(Na0.5K0.5)NbO3-0.04BaTiO3 (BT4) ceramics sintered at 1000∘C have the optimal performance. Additionally, in-depth analysis of the electrical hysteresis revealed that the internal bias field originating from accumulation of space charges at grain boundaries is responsible for the asymmetry in the hysteresis loops.

  4. Dielectric and piezoelectric properties of lead-free Ba0.85Ca0.15Ti0.9-xZr0.1CuxO3 ceramics synthesized by a hydrothermal method

    NASA Astrophysics Data System (ADS)

    Hunpratub, Sitchai; Phokha, Sumalin; Maensiri, Santi; Chindaprasirt, Prinya

    2016-04-01

    Ba0.85Ca0.15Ti0.9Zr0.1-xCuxO3 (BCTZC) nanopowders were synthesized using a hydrothermal method after which they were pressed into discs and sintered in air at 1300 °C for 3 h to form ceramic samples. The phase and microstructure of the powder and ceramic samples were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The XRD results indicated that the ceramic samples exhibited a tetragonal structure and that CuO, BaZrO3 or CaTiO3 impurity phases, which had been present in the powder samples, were not observed. The average grain sizes in the ceramic samples were found to be 17.0, 16.1, 20.0, 18.1 and 19.6 μm for Cu mole fractions x of 0.002, 0.004, 0.006, 0.008 and 0.01, respectively. The dielectric constants, ferroelectric hysteresis loops and piezoelectric charge coefficients of the BCZTC ceramic samples were also investigated. Optimum values for the relative dielectric constant (ɛ‧), tan δ and piezoelectric charge coefficient (d33) of the samples were 3830, 0.03 and 306 pC/N, respectively, in the Cu mole fraction samples with x = 0.002.

  5. Enhanced ferroelectric and piezoelectric response in Mn-doped Bi0.5Na0.5TiO3-BaTiO3 lead-free film by pulsed laser deposition

    NASA Astrophysics Data System (ADS)

    Jin, Chengchao; Wang, Feifei; Leung, Chung Ming; Yao, Qirong; Tang, Yanxue; Wang, Tao; Shi, Wangzhou

    2013-10-01

    Mn-doped Bi0.5Na0.5TiO3-BaTiO3 thin film with the composition around the morphotropic phase boundary was grown on Pt-electrodized Si substrate by pulsed laser deposition. Highly (1 0 0)-oriented film with pure perovskite structure was obtained through carefully controlling the growth conditions. Well-defined ferroelectric P-E loop was obtained with the average remnant polarization Pr and coercive field Ec of ∼11.3 μC/cm2 and ∼6.5 kV/mm, respectively. Polycrystalline structures and multidomain states were revealed by piezoresponse force microscopy and large local strain response was obtained with the normalized strain Smax/Emax up to 92 pm/V. The excellent global electrical properties make it quite promising in environmental-friendly ferroelectric and piezoelectric devices.

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

    PubMed

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

    2011-09-01

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

  7. A study of the temperature dependence of the local ferroelectric properties of c-axis oriented Bi6Ti3Fe2O18 Aurivillius phase thin films: Illustrating the potential of a novel lead-free perovskite material for high density memory applications

    NASA Astrophysics Data System (ADS)

    Faraz, Ahmad; Deepak, Nitin; Schmidt, Michael; Pemble, Martyn E.; Keeney, Lynette

    2015-08-01

    The ability to control the growth, texture and orientation of self-nanostructured lead-free Aurivillius phase thin films can in principle, greatly improve their ferroelectric properties, since in these materials the polarization direction is dependent on crystallite orientation. Here, we report the growth of c-plane oriented Bi6Ti3Fe2O18 (B6TFO) functional oxide Aurivillius phase thin films on c-plane sapphire substrates by liquid injection chemical vapour deposition (LI-CVD). Microstructural analysis reveals that B6TFO thin films annealed at 850°C are highly crystalline, well textured (Lotgering factor of 0.962) and single phase. Typical Aurivillius plate-like morphology with an average film thickness of 110nm and roughness 24nm was observed. The potential of B6TFO for use as a material in lead-free piezoelectric and ferroelectric data storage applications was explored by investigating local electromechanical (piezoelectric) and ferroelectric properties at the nano-scale. Vertical and lateral piezoresponse force microscopy (PFM) reveals stronger in-plane polarization due to the controlled growth of the a-axis oriented grains lying in the plane of the B6TFO films. Switching spectroscopy PFM (SS-PFM) hysteresis loops obtained at higher temperatures (up to 200°C) and at room temperature reveal a clear ferroelectric signature with only minor changes in piezoresponse observed with increasing temperature. Ferroelectric domain patterns were written at 200°C using PFM lithography. Hysteresis loops generated inside the poled regions at room and higher temperatures show a significant increase in piezoresponse due to alignment of the c-axis polarization components under the external electric field. No observable change in written domain patterns was observed after 20hrs of PFM scanning at 200°C, confirming that B6TFO retains polarization over this finite period of time. These studies demonstrate the potential of B6TFO thin films for use in piezoelectric applications at

  8. Extrinsic contribution and non-linear response in lead-free KNN-modified piezoceramics

    NASA Astrophysics Data System (ADS)

    Ochoa, D. A.; García, J. E.; Pérez, R.; Gomis, V.; Albareda, A.; Rubio-Marcos, F.; Fernández, J. F.

    2009-01-01

    Finding lead-free ceramics with good piezoelectric properties is nowadays one of the most important challenges in materials science. The (K, Na, Li)(Nb, Ta, Sb)O3 system is one of the most promising candidates as a lead-free ceramic for transducer applications and is currently the object of important research work. In this paper, (K0.44Na0.52Li0.04)(Nb0.86Ta0.10Sb0.04)O3 was prepared by a conventional ceramic processing route. For this composition, orthorhombic-to-tetragonal phase transition was observed at temperatures very close to room temperature. As a consequence, good room temperature electromechanical properties were observed, displaying good thermal stability. We show that the most important contribution to dielectric, piezoelectric and elastic response comes from extrinsic effects, as was observed in other perovskite based materials. Nonlinearities in electromechanical properties induced by high electric field or mechanical stress were studied. Non-linear dielectric response was found to be less important than for soft PZT ceramics and was analysed within the Rayleigh framework. The results reveal that the non-linear response at room temperature in this material is mainly due to the irreversible wall domain movement.

  9. Piezoelectric PVDF materials performance and operation limits in space environments.

    SciTech Connect

    Dargaville, Tim Richard; Assink, Roger Alan; Clough, Roger Lee; Celina, Mathias Christopher

    2004-11-01

    Piezoelectric polymers based on polyvinylidene fluoride (PVDF) are of interest for large aperture space-based telescopes. Dimensional adjustments of adaptive polymer films are achieved via charge deposition and require a detailed understanding of the piezoelectric material responses which are expected to suffer due to strong vacuum UV, gamma, X-ray, energetic particles and atomic oxygen under low earth orbit exposure conditions. The degradation of PVDF and its copolymers under various stress environments has been investigated. Initial radiation aging studies using gamma- and e-beam irradiation have shown complex material changes with significant crosslinking, lowered melting and Curie points (where observable), effects on crystallinity, but little influence on overall piezoelectric properties. Surprisingly, complex aging processes have also been observed in elevated temperature environments with annealing phenomena and cyclic stresses resulting in thermal depoling of domains. Overall materials performance appears to be governed by a combination of chemical and physical degradation processes. Molecular changes are primarily induced via radiative damage, and physical damage from temperature and AO exposure is evident as depoling and surface erosion. Major differences between individual copolymers have been observed providing feedback on material selection strategies.

  10. Degradation of Piezoelectric Materials for Energy Harvesting Applications

    NASA Astrophysics Data System (ADS)

    Pillatsch, P.; Shashoua, N.; Holmes, A. S.; Yeatman, E. M.; Wright, P. K.

    2014-11-01

    The purpose of energy harvesting is to provide long term alternatives to replaceable batteries across a number of applications. Piezoelectric vibration harvesting provides advantages over other transduction methods due to the ability to generate large voltages even on a small scale. However, the operation in energy harvesting is different from typical sensors or actuators. The applied stress is often at the material limit in order to generate the maximum power output. Under these conditions, the degradation of the materials becomes an important factor for long term deployment. In this work bimorph piezoelectric beams were sub jected to lifetime testing through electromagnetic tip actuation for a large number of cycles. The results of two measurement series at different amplitudes are discussed. The dominant effect observed was a shift in mechanical resonance frequencies of the beams which could be very detrimental to resonant harvesters.

  11. Piezoelectric material for use in a nuclear reactor core

    NASA Astrophysics Data System (ADS)

    Parks, D. A.; Reinhardt, Brian; Tittmann, B. R.

    2012-05-01

    In radiation environments ultrasonic nondestructive evaluation has great potential for improving reactor safety and furthering the understanding of radiation effects and materials. In both nuclear power plants and materials test reactors, elevated temperatures and high levels of radiation present challenges to ultrasonic NDE methodologies. The challenges are primarily due to the degradation of the ultrasonic sensors utilized. We present results from the operation of a ultrasonic piezoelectric transducer, composed of bulk single crystal AlN, in a nuclear reactor core for over 120 MWHrs. The transducer was coupled to an aluminum cylinder and operated in pulse echo mode throughout the irradiation. In addition to the pulse echo testing impedance data were obtained. Further, the piezoelectric coefficient d33 was measured prior to irradiation and found to be 5.5 pC/N which is unchanged from as-grown samples, and in fact higher than the measured d33 for many as-grown samples.

  12. Piezoelectric material for use in a nuclear reactor core

    SciTech Connect

    Parks, D. A.; Reinhardt, Brian; Tittmann, B. R.

    2012-05-17

    In radiation environments ultrasonic nondestructive evaluation has great potential for improving reactor safety and furthering the understanding of radiation effects and materials. In both nuclear power plants and materials test reactors, elevated temperatures and high levels of radiation present challenges to ultrasonic NDE methodologies. The challenges are primarily due to the degradation of the ultrasonic sensors utilized. We present results from the operation of a ultrasonic piezoelectric transducer, composed of bulk single crystal AlN, in a nuclear reactor core for over 120 MWHrs. The transducer was coupled to an aluminum cylinder and operated in pulse echo mode throughout the irradiation. In addition to the pulse echo testing impedance data were obtained. Further, the piezoelectric coefficient d{sub 33} was measured prior to irradiation and found to be 5.5 pC/N which is unchanged from as-grown samples, and in fact higher than the measured d{sub 33} for many as-grown samples.

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

    PubMed

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

    2011-09-01

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

  14. Phase boundary at x =0.03 and its anomalous influence on the structure and properties in the lead-free piezoelectric (1 -x ) N a1 /2B i1 /2Ti O3-(x ) BaTi O3

    NASA Astrophysics Data System (ADS)

    Rao, Badari Narayana; Avdeev, Maxim; Kennedy, Brendan; Ranjan, Rajeev

    2015-12-01

    The complexity associated with local structures continues to pose challenges with regard to the understanding of the structure-property relationship in N a1 /2B i1 /2Ti O3 -based lead-free piezoceramics. (1 -x ) N a1 /2B i1 /2Ti O3-(x ) BaTi O3 is an extensively studied system because of its interesting piezoelectric properties. Recently, a room temperature phase boundary was reported at x =0.03 in this system [Ma et al., Adv. Funct. Mater. 23, 5261 (2013), 10.1002/adfm.201300640]. In the present work we have examined this subtle phase boundary using x-ray diffraction, neutron diffraction, dielectric measurements as a function of composition (x <0.06 ) , temperature, and electric field. Our results show that this boundary separates an R 3 c +C c -like structural state for x <0.03 from an R 3 c + cubiclike structural state for 0.03 ≤x ≤0.05 in the unpoled specimens. This phase boundary is characterized by an anomalous reduction in the depolarization temperature, and a suppression of the tetragonal distortion of the high temperature P 4 b m phase. Our results also provide the clue to understand the pathway leading to the cubiclike structure of the critical composition x =0.06 , known for its highest piezoelectric response.

  15. Characterization of piezoelectric materials for simultaneous strain and temperature sensing for ultra-low frequency applications

    NASA Astrophysics Data System (ADS)

    Nouroz Islam, Mohammad; Seethaler, Rudolf; Shahria Alam, M.

    2015-08-01

    Piezoelectric materials are used extensively in a number of sensing applications ranging from aerospace industries to medical diagnostics. Piezoelectric materials generate charge when they are subjected to strain. However, since measuring charge is difficult at low frequencies, traditional piezoelectric sensors are limited to dynamic applications. In this research an alternative technique is proposed to determine static strain that relies upon the measurement of piezoelectric capacitance and resistance using piezoelectric sensors. To demonstrate the validity of this approach, the capacitance and resistance of a piezoelectric patch sensor was characterized for a wide range of strain and temperature. The study shows that the piezoelectric capacitance is sensitive to both strain and temperature while the resistance is mostly dependent on the temperature variation. The findings can be implemented to obtain thermally compensated static strain from piezoelectric sensors, which does not require an additional temperature sensor.

  16. Wavefront conjugation using electron-gun-controlled piezoelectric materials

    NASA Astrophysics Data System (ADS)

    Nelson, George C.; Main, John A.; Martin, Jeffrey W.

    2000-07-01

    Current adaptive optics designs often rely upon multiple actuators to mechanically deform mirrored surfaces. The spatial resolution of control is dependent upon the physical size of these actuators and the number of actuators present. Piezoelectric materials may be used for actuation however the classical control methods of these materials also rely on discrete areas of actuation and require lead wiring for each electrode, patch, or stack utilized. Electron gun control of piezoelectric materials eliminates the need for discrete, segmented electrodes and their associated lead wiring. This method also holds the potential for much finer control resolution since the restraining parameter is beam size. Lightweight piezoelectric ceramics may possibly be used as wavefront conjugating mirrors. Piezo-ceramic plates can be actuated with an electron gun and a single distributed electrode of optical quality. The electron gun functions as a pointing device while varying the potential, referred to as backpressure, of the single electrode controls the magnitude of actuation. By using this method, future corrective optics may significantly surpass current design performance without significantly increasing system complexity.

  17. 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.

  18. 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.

  19. 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

  20. 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.

  1. Mechanical and vibration testing of carbon fiber composite material with embedded piezoelectric sensors

    NASA Astrophysics Data System (ADS)

    Duffy, Kirsten P.; Lerch, Bradley A.; Wilmoth, Nathan G.; Kray, Nicholas; Gemeinhardt, Gregory

    2012-04-01

    Piezoelectric materials have been proposed as a means of decreasing turbomachinery blade vibration either through a passive damping scheme, or as part of an active vibration control system. For polymer matrix fiber composite (PMFC) blades, the piezoelectric elements could be embedded within the blade material, protecting the brittle piezoceramic material from the airflow and from debris. Before implementation of a piezoelectric element within a PMFC blade, the effect on PMFC mechanical properties needs to be understood. This study attempts to determine how the inclusion of a packaged piezoelectric patch affects the material properties of the PMFC. Composite specimens with embedded piezoelectric patches were tested in four-point bending, short beam shear, and flatwise tension configurations. Results show that the embedded piezoelectric material does decrease the strength of the composite material, especially in flatwise tension, attributable to failure at the interface or within the piezoelectric element itself. In addition, the sensing properties of the post-cured embedded piezoelectric materials were tested, and performed as expected. The piezoelectric materials include a non-flexible patch incorporating solid piezoceramic material, and two flexible patch types incorporating piezoelectric fibers. The piezoceramic material used in these patches was Navy Type-II PZT.

  2. Mechanical and Vibration Testing of Carbon Fiber Composite Material with Embedded Piezoelectric Sensors

    NASA Technical Reports Server (NTRS)

    Duffy, Kirsten P.; Lerch, Bradley A.; Wilmoth, Nathan G.; Kray, Nicholas; Gemeinhardt, Gregory

    2012-01-01

    Piezoelectric materials have been proposed as a means of decreasing turbomachinery blade vibration either through a passive damping scheme, or as part of an active vibration control system. For polymer matrix fiber composite (PMFC) blades, the piezoelectric elements could be embedded within the blade material, protecting the brittle piezoceramic material from the airflow and from debris. Before implementation of a piezoelectric element within a PMFC blade, the effect on PMFC mechanical properties needs to be understood. This study attempts to determine how the inclusion of a packaged piezoelectric patch affects the material properties of the PMFC. Composite specimens with embedded piezoelectric patches were tested in four-point bending, short beam shear, and flatwise tension configurations. Results show that the embedded piezoelectric material does decrease the strength of the composite material, especially in flatwise tension, attributable to failure at the interface or within the piezoelectric element itself. In addition, the sensing properties of the post-cured embedded piezoelectric materials were tested, and performed as expected. The piezoelectric materials include a non-flexible patch incorporating solid piezoceramic material, and two flexible patch types incorporating piezoelectric fibers. The piezoceramic material used in these patches was Navy Type-II PZT.

  3. 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. PMID:26584490

  4. Periodical Microstructures Based on Novel Piezoelectric Material for Biomedical Applications

    PubMed Central

    Janusas, Giedrius; Ponelyte, Sigita; Brunius, Alfredas; Guobiene, Asta; Prosycevas, Igoris; Vilkauskas, Andrius; Palevicius, Arvydas

    2015-01-01

    A novel cantilever type piezoelectric sensing element was developed. Cost-effective and simple fabrication design allows the use of this element for various applications in the areas of biomedicine, pharmacy, environmental analysis and biosensing. This paper proposes a novel piezoelectric composite material whose basic element is PZT and a sensing platform where this material was integrated. Results showed that a designed novel cantilever-type element is able to generate a voltage of up to 80 µV at 50 Hz frequency. To use this element for sensing purposes, a four micron periodical microstructure was imprinted. Silver nanoparticles were precipitated on the grating to increase the sensitivity of the designed element, i.e., Surface Plasmon Resonance (SPR) effect appears in the element. To tackle some issues (a lack of sensitivity, signal delays) the element must have certain electronic and optical properties. One possible solution, proposed in this paper, is a combination of piezoelectricity and SPR in a single element. PMID:26694398

  5. Periodical Microstructures Based on Novel Piezoelectric Material for Biomedical Applications.

    PubMed

    Janusas, Giedrius; Ponelyte, Sigita; Brunius, Alfredas; Guobiene, Asta; Prosycevas, Igoris; Vilkauskas, Andrius; Palevicius, Arvydas

    2015-01-01

    A novel cantilever type piezoelectric sensing element was developed. Cost-effective and simple fabrication design allows the use of this element for various applications in the areas of biomedicine, pharmacy, environmental analysis and biosensing. This paper proposes a novel piezoelectric composite material whose basic element is PZT and a sensing platform where this material was integrated. Results showed that a designed novel cantilever-type element is able to generate a voltage of up to 80 µV at 50 Hz frequency. To use this element for sensing purposes, a four micron periodical microstructure was imprinted. Silver nanoparticles were precipitated on the grating to increase the sensitivity of the designed element, i.e., Surface Plasmon Resonance (SPR) effect appears in the element. To tackle some issues (a lack of sensitivity, signal delays) the element must have certain electronic and optical properties. One possible solution, proposed in this paper, is a combination of piezoelectricity and SPR in a single element. PMID:26694398

  6. Lead-free BNT composite film for high-frequency broadband ultrasonic transducer applications.

    PubMed

    Yan, Xingwei; Ji, Hongfen; Lam, Kwok Ho; Chen, Ruimin; Zheng, Fan; Ren, Wei; Zhou, Qifa; Shung, K Kirk

    2013-07-01

    A lead-free Bi0.5Na0.5TiO3 (BNT) piezoelectric composite thick film with a thickness of ~11 μm has been fabricated using a modified sol-gel method. Dielectric constant, remnant polarization, and coercive field of the BNT composite film were found to be 1018, 22.6 μC/cm2, and 76.1 kV/cm, respectively. The film was used to fabricate a high-frequency needle transducer and the performance of the transducer was measured. The transducer without a matching layer exhibits a center frequency of 98 MHz and a -6-dB bandwidth of 86%. A wire phantom image acquired using the transducer shows an axial resolution of 15 ¿m and lateral resolution of 68 μm, respectively. Results from this study suggest that the BNT composite film is a promising lead-free piezoelectric material for high-frequency broadband ultrasonic transducer applications. PMID:25004521

  7. New potassium-sodium niobate lead-free piezoceramic: Giant-d33 vs. sintering temperature

    NASA Astrophysics Data System (ADS)

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

    2014-03-01

    The objective of this work is to achieve a giant piezoelectric constant in (K,Na)NbO3-based lead-free ceramics, and then 0.96K0.46Na0.54Nb0.95Sb0.05O3-0.04Bi0.5(Na0.82K0.18)0.5ZrO3 lead-free piezoceramics were designed and prepared by optimizing the sintering temperature (TS). The rhombohedral-tetragonal phase boundary is found in the ceramics sintered at 1070 ˜ 1105 °C and is suppressed when sintered at low TS of 1060 ˜ 1065 °C. The threshold for TS is 1070 °C in terms of their ferroelectric and piezoelectric properties owing to the difference in the phase boundary and the microstructure, and a large d33 of 388 ˜ 465 pC/N could be attained in a wide TS range of 1070 ˜ 1105 °C, benefiting their practical applications because of broad TS. More interestingly, the ceramic sintered at 1075 °C has a giant d33 of ˜465 pC/N. We think that such a giant d33 of this material system can benefit the development of (K,Na)NbO3-based piezoceramics.

  8. Structure, electrical properties and temperature characteristics of Bi0.5Na0.5TiO3-Bi0.5K0.5TiO3-Bi0.5Li0.5TiO3 lead-free piezoelectric ceramics

    NASA Astrophysics Data System (ADS)

    Lin, Dunmin; Zheng, Qiaoji; Xu, Chenggang; Kwok, K. W.

    2008-11-01

    (1- x- y)Bi0.5Na0.5TiO3- xBi0.5K0.5TiO3- yBi0.5Li0.5TiO3 lead-free piezoelectric ceramics have been prepared by an ordinary sintering technique, and their structure, electrical properties, and temperature characteristics have been studied systematically. The ceramics can be well-sintered at 1050-1150 °C. The increase in K+ concentration decreases the grain-growth rate and promotes the formation of grains with a cubic shape, while the addition of Li+ decreases greatly the sintering temperature and assists in the densification of BNT-based ceramics. The results of XRD diffraction show that K+ and Li+ diffuse into the Bi0.5Na0.5TiO3 lattices to form a solid solution with a pure perovskite structure. As x increases from 0.05 to 0.50, the ceramics transform gradually from rhombohedral phase to tetragonal phase and consequently a morphotropic phase boundary (MPB) is formed at 0.15≤ x≤0.25. The concentration y of Li+ has no obvious influence on the crystal structure of the ceramics. Compared with pure Bi0.5Na0.5TiO3, the partial substitution of K+ and Li+ for Na+ lowers greatly the coercive field E c and increases the remanent polarization P r of the ceramics. Because of the MPB, lower E c and large P r, the piezoelectricity of the ceramics is improved significantly. For the ceramics with the compositions near the MPB ( x=0.15-0.25 and y=0.05-0.10), the piezoelectric properties become optimum: piezoelectric coefficient d 33=147-231 pC/N and planar electromechanical coupling factor k P=20.2-41.0%. In addition, the ceramics exhibit relaxor characteristic, which probably results from the cation disordering in the 12-fold coordination sites. The depolarization temperature T d shows a strong dependence on the concentration x of K+ and reaches the lowest values at the MPB. The temperature dependences of the ferroelectric and dielectric properties at high temperatures may imply that the ceramics may contain both the polar and non-polar regions at temperatures above T d.

  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. Enhancement of the electrical-field-induced strain in lead-free Bi0.5(Na,K)0.5TiO3-based piezoelectric ceramics: Role of the phase transition

    NASA Astrophysics Data System (ADS)

    Quyet, Nguyen Van; Bac, Luong Huu; Dung, Dang Duc

    2015-04-01

    In this work, a strong enhancement of the electric-field-induced strain in Bi0.5(Na,K)0.5TiO3-based ceramics was observed via lithium(Li) addition. The Li-added Bi0.5(Na,K)0.5TiO3-based ceramics exhibited a strain of 0.40% under an electric field of 6 kV/mm, which was almost twice the value without the Li dopant (0.21%). We obtained the highest S max/ E max value of 668 pm/V for 4-mol% Li addition, which was due to the phase transition from pseudocubic to rhombohedral symmetry and/or to the distorted tetragonal structure. We suggest that controlling the phase transition in ferroelectric materials is a way to enhance the electric-field-induced giant strain and that the phase transition from the non-polar phase to the polar phase results in a giant electric-fieldinduced strain, which overcomes the result due to the phase transition from the polar phase to the non-polar phase and/or the distorted structure. We expect our work to open new ways to enhance the electric-filed-induced giant strain to a value that is comparable to the value for Pb(Zr,Ti)O3 (PZT)-based ceramics.

  11. 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.

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

    SciTech Connect

    Garg, Rohini; Narayana Rao, Badari; Ranjan, Rajeev; Senyshyn, Anatoliy

    2013-12-21

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

  13. 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.

  14. Palpationlike soft-material elastic modulus measurement using piezoelectric cantilevers

    NASA Astrophysics Data System (ADS)

    Szewczyk, Steven T.; Shih, Wan Y.; Shih, Wei-Heng

    2006-04-01

    We have developed an all-electrical piezoelectric cantilever sensor that can self-excite and self-detect for tissue elastic modulus measurement. An all-electrical piezoelectric cantilever is consisted of a sandwich of piezoelectric layer, e.g., lead zirconate titanate (PZT), a nonpiezoelectric layer, e.g., stainless steel, and a second piezoelectric layer. The top piezoelectric layer serves as the driving layer (self-exciting) and the second piezoelectric layer as the sensing layer (self-sensing). The driving and sensing piezoelectric layers may be of different lengths. Applying a dc voltage across the driving PZT layer causes the piezoelectric cantilever to bend. The resultant bending stress in the sensing PZT layer generates a piezoelectric voltage across the sensing PZT layer that rises rapidly to a maximum before it decays with time. The maximum induced voltage was used to measure the axial displacement of the piezoelectric cantilever. With its force generation and displacement sensing capability, we show that an all-electrical piezoelectric cantilever can measure the elastic modulus of tissues both under the regular compression geometry and the flat-punch indentation geometry. In addition, the sensor can map the local elastic modulus variations of tissues much like palpation.

  15. A miniature airflow energy harvester from piezoelectric materials

    NASA Astrophysics Data System (ADS)

    Sun, H.; Zhu, D.; White, N. M.; Beeby, S. P.

    2013-12-01

    This paper describes design, simulation, fabrication, and testing of a miniature wind energy harvester based on a flapping cantilevered piezoelectric beam. The wind generator is based on oscillations of a cantilever that faces the direction of the airflow. The oscillation is amplified by interactions between an aerofoil attached on the cantilever and a bluff body placed in front of the aerofoil. A piezoelectric transducer with screen printed PZT materials is used to extract electrical energy. To achieve the optimum design of the harvester, both computational simulations and experiments have been carried out to investigate the structure. A prototype of the wind harvester, with the volume of 37.5 cm3 in total, was fabricated by thick-film screen printing technique. Wind tunnel test results are presented to determine the optimum structure and to characterize the performance of the harvester. The optimized device finally achieved a working wind speed range from 1.5 m/s to 8 m/s. The power output was ranging from 0.1 to 0.86 μW and the open-circuit output voltage was from 0.5 V to 1.32 V.

  16. 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.

  17. Hot-stage transmission electron microscopy study of (Na, K)NbO3 based lead-free piezoceramics

    NASA Astrophysics Data System (ADS)

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

    2014-07-01

    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, (Na0.52K0.48-x)(Nb0.95-xTa0.05)-xLiSbO3, 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.

  18. 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.

  19. Fundamental Analysis of Piezocatalysis Process on the Surfaces of Strained Piezoelectric Materials

    PubMed Central

    Starr, Matthew B.; Wang, Xudong

    2013-01-01

    Recently, the strain state of a piezoelectric electrode has been found to impact the electrochemical activity taking place between the piezoelectric material and its solution environment. This effect, dubbed piezocatalysis, is prominent in piezoelectric materials because the strain state and electronic state of these materials are strongly coupled. Herein we develop a general theoretical analysis of the piezocatalysis process utilizing well-established piezoelectric, semiconductor, molecular orbital and electrochemistry frameworks. The analysis shows good agreement with experimental results, reproducing the time-dependent voltage drop and H2 production behaviors of an oscillating piezoelectric Pb(Mg1/3Nb2/3)O3-32PbTiO3 (PMN-PT) cantilever in deionized water environment. This study provides general guidance for future experiments utilizing different piezoelectric materials, such as ZnO, BaTiO3, PbTiO3, and PMN-PT. Our analysis indicates a high piezoelectric coupling coefficient and a low electrical conductivity are desired for enabling high electrochemical activity; whereas electrical permittivity must be optimized to balance piezoelectric and capacitive effects. PMID:23831736

  20. Fundamental analysis of piezocatalysis process on the surfaces of strained piezoelectric materials.

    PubMed

    Starr, Matthew B; Wang, Xudong

    2013-01-01

    Recently, the strain state of a piezoelectric electrode has been found to impact the electrochemical activity taking place between the piezoelectric material and its solution environment. This effect, dubbed piezocatalysis, is prominent in piezoelectric materials because the strain state and electronic state of these materials are strongly coupled. Herein we develop a general theoretical analysis of the piezocatalysis process utilizing well-established piezoelectric, semiconductor, molecular orbital and electrochemistry frameworks. The analysis shows good agreement with experimental results, reproducing the time-dependent voltage drop and H₂ production behaviors of an oscillating piezoelectric Pb(Mg₁/₃Nb₂/₃)O₃-32PbTiO₃ (PMN-PT) cantilever in deionized water environment. This study provides general guidance for future experiments utilizing different piezoelectric materials, such as ZnO, BaTiO₃, PbTiO₃, and PMN-PT. Our analysis indicates a high piezoelectric coupling coefficient and a low electrical conductivity are desired for enabling high electrochemical activity; whereas electrical permittivity must be optimized to balance piezoelectric and capacitive effects. PMID:23831736

  1. 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.

  2. 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.

  3. 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.

  4. 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. PMID:23485349

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

    PubMed Central

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

    2013-01-01

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

  6. Understanding the quasi-static thermo-electro-mechanical response of piezoelectric materials

    NASA Astrophysics Data System (ADS)

    Ganley, Jeffrey Mark

    2007-12-01

    Piezoelectricity describes the behavior of a class of materials which exhibit a relationship between mechanical strain and electrical field. Piezoelectric materials can be crystals (e.g. quartz), ceramic (e.g. lead-zirconate-titanate---PZT---the primary focus of the present research), or polymers (e.g. polyvinylidine-fluoride - PVDF). Piezopolymers and piezoceramics offer a significant improvement in piezoelectric properties over naturally occurring piezoelectrics like quartz. In the last five years, research in piezoelectrics has begun to change focus from the more traditional sensor/actuator applications to utilizing piezoelectric materials in energy harvesting applications. The present research will explore the very low frequency response of piezoelectrics, including several energy harvesting applications, as well as the interactions between thermal, mechanical and electrical energy in a thermally driven piezoelectric energy generation system. In Chapter 1, the history of piezoelectric research and development is given, along with an overview of piezoelectricity for those readers who are not familiar with the topic. In Chapter 2, current investigations in piezoelectric energy harvesting research are summarized. The present research, namely understanding the quasi-static thermo-electro-mechanical response of piezoelectric materials is also summarized. In addition, two applications: thermal management in a satellite and energy harvesting from a vibrating highway bridge are detailed as motivators for the present research. Chapter 3 gives a summary of the relevant piezoelectric theory. In addition, electrical circuit theory and thermodynamic heat capacity/heat energy considerations required to complete the present research are given. Chapter 4 provides a summary of the experimental testing completed during the course of the present research. Significant testing, including determination of the PZT/Aluminum substrate sample time constants, thermal calibration testing

  7. A review of piezoelectric polymers as functional materials for electromechanical transducers

    NASA Astrophysics Data System (ADS)

    Ramadan, Khaled S.; Sameoto, D.; Evoy, S.

    2014-03-01

    Polymer based MEMS and microfluidic devices have the advantages of mechanical flexibility, lower fabrication cost and faster processing over silicon based ones. Also, many polymer materials are considered biocompatible and can be used in biological applications. A valuable class of polymers for microfabricated devices is piezoelectric functional polymers. In addition to the normal advantages of polymers, piezoelectric polymers can be directly used as an active material in different transduction applications. This paper gives an overview of piezoelectric polymers based on their operating principle. This includes three main categories: bulk piezoelectric polymers, piezocomposites and voided charged polymers. State-of-the-art piezopolymers of each category are presented with a focus on fabrication techniques and material properties. A comparison between the different piezoelectric polymers and common inorganic piezoelectric materials (PZT, ZnO, AlN and PMN-PT) is also provided in terms of piezoelectric properties. The use of piezopolymers in different electromechanical devices is also presented. This includes tactile sensors, energy harvesters, acoustic transducers and inertial sensors.

  8. Soft-materials elastic and shear moduli measurement using piezoelectric cantilevers

    NASA Astrophysics Data System (ADS)

    Markidou, Anna; Shih, Wan Y.; Shih, Wei-Heng

    2005-06-01

    We have developed a soft-material elastic modulus and shear modulus sensor using piezoelectric cantilevers. A piezoelectric cantilever is consisted of a highly piezoelectric layer, e.g., lead-zirconate-titanate bonded to a nonpiezoelectric layer, e.g., stainless steel. Applying an electric field in the thickness direction causes a piezoelectric cantilever to bend, generating an axial displacement or force. When a piezoelectric cantilever is in contact with an object, this electric field-generated axial displacement is reduced due to the resistance by the object. With a proper design of the piezoelectric cantilever's geometry, its axial displacements with and without contacting the object could be accurately measured. From these measurements the elastic modulus of the object can be deduced. In this study, we tailored the piezoelectric cantilevers for measuring the elastic and shear moduli of tissue-like soft materials with forces in the submilli Newton to milliNewton range. Elastic moduli and shear moduli of soft materials were measured using piezoelectric cantilevers with a straight tip and an L-shaped tip, respectively. Using gelatin and commercial rubber material as model soft tissues, we showed that a piezoelectric cantilever 1.5-2cm long could measure the elastic modulus and the shear modulus of a small soft material sample (1-3mm wide) in the small strain range (<1%). For samples 5mm high, the resultant compressive (shear) strains were less than 0.5% (1%). The measurements were validated by (1) comparing the measured Young's modulus of the commercial rubber sample with its known value and (2) by measuring both the Young's modulus and shear modulus on the samples and confirming the thus deduced Poisson's ratios with the separately measured Poisson's ratios.

  9. 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. PMID:27136116

  10. 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.

  11. Compliant Electrode and Composite Material for Piezoelectric Wind and Mechanical Energy Conversions

    NASA Technical Reports Server (NTRS)

    Chen, Bin (Inventor)

    2015-01-01

    A thin film device for harvesting energy from wind. The thin film device includes one or more layers of a compliant piezoelectric material formed from a composite of a polymer and an inorganic material, such as a ceramic. Electrodes are disposed on a first side and a second side of the piezoelectric material. The electrodes are formed from a compliant material, such as carbon nanotubes or graphene. The thin film device exhibits improved resistance to structural fatigue upon application of large strains and repeated cyclic loadings.

  12. Flexible-CMOS and biocompatible piezoelectric AlN material for MEMS applications

    NASA Astrophysics Data System (ADS)

    Jackson, Nathan; Keeney, Lynette; Mathewson, Alan

    2013-11-01

    The development of a CMOS compatible flexible piezoelectric material is desired for numerous applications and in particular for biomedical MEMS devices. Aluminum nitride (AlN) is the most commonly used CMOS compatible piezoelectric material, which is typically deposited on Si in order to enhance the c-axis (002) crystal orientation which gives AlN its high piezoelectric properties. This paper reports on the successful deposition of AlN on polyimide (PI-2611) material. The AlN deposited has a FWHM (002) value of 5.1° and a piezoelectric d33 value of 1.12 pm V-1, and SEM images show high quality columnar grains. The highly crystalline AlN material is due to the semi-crystalline properties of the polyimide film used. Cytotoxicity testing showed the AlN/polyimide material to be non-toxic to 3T3 cells and primary neurons. Surface properties of the AlN/polyimide film were evaluated as they have a significant effect on the adhesion of cells to the film. The results show neurons adhering to the AlN surface. The results of this paper show the characterization of a new flexible-CMOS and biocompatible AlN/polyimide material for MEMS devices with improved crystallinity and piezoelectric properties.

  13. Piezoelectric materials selection for sensor applications using finite element and multiple attribute decision-making approaches

    NASA Astrophysics Data System (ADS)

    Kumar, Anuruddh; Sharma, Anshul; Kumar, Rajeev; Vaish, Rahul; Chauhan, Vishal S.; Bowen, C. R.

    2015-03-01

    This paper examines the selection and performance evaluation of a variety of piezoelectric materials for cantilever-based sensor applications. The finite element analysis method is implemented to evaluate the relative importance of materials properties such as Young's Modulus (E), piezoelectric stress constants (e31), dielectric constant (ɛ) and Poisson's ratio (υ) for cantilever-based sensor applications. An analytic hierarchy process (AHP) is used to assign weights to the properties that are studied for the sensor structure under study. A technique for order preference by similarity to ideal solution (TOPSIS) is used to rank the performance of the piezoelectric materials in the context of sensor voltage outputs. The ranking achieved by the TOPSIS analysis is in good agreement with the results obtained from finite element method simulation. The numerical simulations show that K0.5Na0.5NbO3-LiSbO3 (KNN-LS) materials family is important for sensor application. Young's modulus (E) is most influencing material's property followed by piezoelectric constant (e31), dielectric constant (ɛ) and Poisson's ratio (υ) for cantilever-based piezoelectric sensor applications.

  14. The Effect of Temperature Dependent Material Nonlinearities on the Response of Piezoelectric Composite Plates

    NASA Technical Reports Server (NTRS)

    Lee, Ho-Jun; Saravanos, Dimitris A.

    1997-01-01

    Previously developed analytical formulations for piezoelectric composite plates are extended to account for the nonlinear effects of temperature on material properties. The temperature dependence of the composite and piezoelectric properties are represented at the material level through the thermopiezoelectric constitutive equations. In addition to capturing thermal effects from temperature dependent material properties, this formulation also accounts for thermal effects arising from: (1) coefficient of thermal expansion mismatch between the various composite and piezoelectric plies and (2) pyroelectric effects on the piezoelectric material. The constitutive equations are incorporated into a layerwise laminate theory to provide a unified representation of the coupled mechanical, electrical, and thermal behavior of smart structures. Corresponding finite element equations are derived and implemented for a bilinear plate element with the inherent capability to model both the active and sensory response of piezoelectric composite laminates. Numerical studies are conducted on a simply supported composite plate with attached piezoceramic patches under thermal gradients to investigate the nonlinear effects of material property temperature dependence on the displacements, sensory voltages, active voltages required to minimize thermal deflections, and the resultant stress states.

  15. Piezoelectric and electrostrictive materials for transducer applications, volume 1

    NASA Astrophysics Data System (ADS)

    Cross, L. E.; Newnham, R. E.; Barsch, G. R.; Biggers, J. V.

    1988-03-01

    The topics covered under the program are reported under three major topic areas: Piezoelectric and Related Composites, Electrostriction, Phenomenology and Properties of Conventional Ceramic, and Piezoelectrics. A brief report is also given of related studies required to support and supplement work on the three major areas, under the title Associated Programs. The year has seen major personnel changes at the Post-Doctoral and Graduate Assistant levels as befits a university based program and new personnel are now in place. The summer apprentice program under ONR sponsorship on this program has again given research opportunity to four upward bound high school students who joined Universities in Science and Engineering programs in the fall of 1987.

  16. Nonlinear dielectric response in piezoelectric materials for underwater transducers

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

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

  17. Using piezo-electric material to simulate a vibration environment

    DOEpatents

    Jepsen, Richard A.; Davie, Neil T.; Vangoethem, Douglas J.; Romero, Edward F.

    2010-12-14

    A target object can be vibrated using actuation that exploits the piezo-electric ("PE") property. Under combined conditions of vibration and centrifugal acceleration, a centrifugal load of the target object on PE vibration actuators can be reduced by using a counterweight that offsets the centrifugal loading. Target objects are also subjected to combinations of: spin, vibration, and acceleration; spin and vibration; and spin and acceleration.

  18. 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.

  19. Piezoelectrically-induced trap-depth reduction model of elastico-mechanoluminescent materials

    NASA Astrophysics Data System (ADS)

    Chandra, B. P.; Chandra, V. K.; Jha, Piyush

    2015-03-01

    Considering the detrapping of charge carriers due to reduction in trap-depth caused by piezoelectric field produced by applied pressure, an expression is derived for the detrapping rate of electrons. Then, an expression is obtained for the rate of generation of excited ions produced during capture of detrapped electrons by Eu3+ ions in persistent luminescent materials or by the energy released during electron-hole recombination in ZnS:Mn crystals. Finally, an expression is explored for the elastico-mechanoluminescence (EML) intensity, which is able to explain satisfactorily the characteristics of EML for the application of static pressure as well as for impact pressure. The total number of detrapped electrons and the total EML intensity are found to increase linearly with the electrostatic energy of the crystals in piezoelectric field. It is shown that the EML intensity should increase with the EML efficiency, number of crystallites (volume of sample), concentration of local piezoelectric regions in crystallites, piezoelectric constant of local piezoelectric regions, average length of the local piezoelectric regions, total number of electron traps, pressing rate, and applied pressure, and it should be higher for the materials having low value of threshold pressure and low value of trap-depth in unstressed condition. On the basis of the piezoelectrically-induced trap-depth reduction model of EML reported in the present investigation novel intense elastico mechanoluminescent materials having repetitive EML with undiminished intensity for successive loadings can be tailored which may find applications in sensing, imaging, lighting, colored displays, and other mechano-optical devices.

  20. 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.

  1. The use of real or complex coupling coefficients for lossy piezoelectric materials.

    PubMed

    Piquette, Jean C; McLaughlin, Elizabeth A

    2009-04-01

    Two competing approaches for calculating coupling coefficients for lossy piezoelectric materials, one producing a real result and the other a complex result, are compared and analyzed. It is found that the complex coupling coefficient suffers from mathematical difficulties, which the real coupling coefficient does not exhibit. Moreover, it is pointed out that a prediction made by the complex coupling coefficient theory conflicts with experiment while the corresponding real coupling coefficient theory prediction does not. When a coupling coefficient of interest has been computed from the real coupling coefficient theory using piezoelectric equations having intensive independent variables, the resulting expression has the same algebraic form as the corresponding static coupling coefficient formula. Moreover, only the real parts of the piezoelectric, elastic, and dielectric material properties appear. PMID:19406711

  2. 3D optical printing of piezoelectric nanoparticle-polymer composite materials.

    PubMed

    Kim, Kanguk; Zhu, Wei; Qu, Xin; Aaronson, Chase; McCall, William R; Chen, Shaochen; Sirbuly, Donald J

    2014-10-28

    Here we demonstrate that efficient piezoelectric nanoparticle-polymer composite materials can be optically printed into three-dimensional (3D) microstructures using digital projection printing. Piezoelectric polymers were fabricated by incorporating barium titanate (BaTiO3, BTO) nanoparticles into photoliable polymer solutions such as polyethylene glycol diacrylate and exposing to digital optical masks that could be dynamically altered to generate user-defined 3D microstructures. To enhance the mechanical-to-electrical conversion efficiency of the composites, the BTO nanoparticles were chemically modified with acrylate surface groups, which formed direct covalent linkages with the polymer matrix under light exposure. The composites with a 10% mass loading of the chemically modified BTO nanoparticles showed piezoelectric coefficients (d(33)) of ∼ 40 pC/N, which were over 10 times larger than composites synthesized with unmodified BTO nanoparticles and over 2 times larger than composites containing unmodified BTO nanoparticles and carbon nanotubes to boost mechanical stress transfer efficiencies. These results not only provide a tool for fabricating 3D piezoelectric polymers but lay the groundwork for creating highly efficient piezoelectric polymer materials via nanointerfacial tuning. PMID:25046646

  3. Lead-free BaTiO3 nanowires-based flexible nanocomposite generator

    NASA Astrophysics Data System (ADS)

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

    2014-07-01

    We have synthesized BaTiO3 nanowires (NWs) via a simple hydrothermal method at low temperature and developed a lead-free, flexible nanocomposite generator (NCG) device by a simple, low-cost, and scalable spin-coating method. The hydrothermally grown BaTiO3 NWs are mixed in a polymer matrix without a toxic dispersion enhancer to produce a piezoelectric nanocomposite (p-NC). During periodical and regular bending and unbending motions, the NCG device fabricated by utilizing a BaTiO3 NWs-polydimethylsiloxane (PDMS) composite successfully harvests the output voltage of ~7.0 V and current signals of ~360 nA, which are utilized to drive a liquid crystal display (LCD). We also characterized the instantaneous power (~1.2 μW) of the NCG device by calculating the load voltage and current through the connected external resistance.We have synthesized BaTiO3 nanowires (NWs) via a simple hydrothermal method at low temperature and developed a lead-free, flexible nanocomposite generator (NCG) device by a simple, low-cost, and scalable spin-coating method. The hydrothermally grown BaTiO3 NWs are mixed in a polymer matrix without a toxic dispersion enhancer to produce a piezoelectric nanocomposite (p-NC). During periodical and regular bending and unbending motions, the NCG device fabricated by utilizing a BaTiO3 NWs-polydimethylsiloxane (PDMS) composite successfully harvests the output voltage of ~7.0 V and current signals of ~360 nA, which are utilized to drive a liquid crystal display (LCD). We also characterized the instantaneous power (~1.2 μW) of the NCG device by calculating the load voltage and current through the connected external resistance. Electronic supplementary information (ESI) available: PDF materials involve the linear superposition test results (Fig. S1) and the durability test results (Fig. S2) of BaTiO3 NWs-based NCG device. A video file (Video S1) shows the power up of an LCD screen by the NCG device without any external energy source. See DOI: 10.1039/c4nr

  4. Effect of various shapes and materials on the generated power for piezoelectric energy harvesting system

    NASA Astrophysics Data System (ADS)

    Kaur, Sarabjeet; Graak, Pinki; Gupta, Ankita; Chhabra, Priya; Kumar, Dinesh; Shetty, Arjun

    2016-04-01

    Piezoelectric energy harvesting systems are used to convert vicinity vibrations into useful electrical energy. Effect of various shapes and materials open the gateway towards the choice of maximum power generation for the micro and nano world. Comsol Multiphysics was used to simulate the four designed shapes named as Pi, E, Rectangular and T in the size range of less than 1mm but greater than 1 micron. Designed shapes worked under the impact of ambient vibrations using few piezoelectric materials for the maximum power generation so that traditional power sources can be replaced with such piezoelectric energy harvester. A layer of piezoelectric material (PZT-5H, AlN, BaTiO3) of thickness 0.5 µm is added to the cantilever and the base material is silicon of thickness 1.5 µm. Simulations were performed using the piezoelectric device module of Comsol Multiphysics. All three materials were studied for the all four cantilever geometries. The generated power was observed maximum as 382.5 µW in case of the barium titanate material with rectangular shape geometry but the displacement is 0.132 µm which is very less whereas E shape cantilever shows the maximum displacement of 0.6078 µm in case of PZT-5H, Hence rectangular shape with barium titanate material is concluded to be good for maximum power generation but the displacement factor cannot be neglected, hence the cantilever with E shape geometry is considered as the best with a generated power of 49.005 µW and a displacement of 0.6078 µm.

  5. Active Vibration Reduction of Titanium Alloy Fan Blades (FAN1) Using Piezoelectric Materials

    NASA Technical Reports Server (NTRS)

    Choi, Benjamin; Kauffman, Jeffrey; Duffy, Kirsten; Provenza, Andrew; Morrison, Carlos

    2010-01-01

    The NASA Glenn Research Center is developing smart adaptive structures to improve fan blade damping at resonances using piezoelectric (PE) transducers. In this paper, a digital resonant control technique emulating passive shunt circuits is used to demonstrate vibration reduction of FAN1 Ti real fan blade at the several target modes. Single-mode control and multi-mode control using one piezoelectric material are demonstrated. Also a conceptual study of how to implement this digital control system into the rotating fan blade is discussed.

  6. SAW filter manufacture and piezoelectric materials evaluation based on printed electronics technology

    NASA Astrophysics Data System (ADS)

    Liu, Xiao-chen; Li, Kun; Xuan, Xiu-wei; Cao, Yang; Teng, Jian-fu

    2014-09-01

    In this paper, the silver nanoparticle ink and ink-jet printing technology are used to manufacture the surface acoustic wave (SAW) filters. The characteristics of three common substrate piezoelectric materials of ST-quartz, Y36°-LiTaO3 and Y128°-LiNbO3 are evaluated. The experimental results show that Y128°-LiNbO3 matches the ink much better than others. The printed SAW filter with Y128°-LiNbO3 as piezoelectric substrate is realized, and its center frequency and bandwidth are 18.4 MHz and 500 kHz, respectively.

  7. Piezoelectric MEMS for energy harvesting

    NASA Astrophysics Data System (ADS)

    Kanno, Isaku

    2015-12-01

    Recently, piezoelectric MEMS have been intensively investigated to create new functional microdevices, and some of them have already been commercialized such as MEMS gyrosensors or miropumps of inkjet printer head. Piezoelectric energy harvesting is considered to be one of the promising future applications of piezoelectric MEMS. In this report, we introduce the deposition of the piezoelectric PZT thin films as well as lead-free KNN thin films. We fabricated piezoelectric energy harvesters of PZT and KNN thin films deposited on stainless steel cantilevers and compared their power generation performance.

  8. 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.

  9. 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.

  10. Method for generation of THz frequency radiation and sensing of large amplitude material strain waves in piezoelectric materials

    DOEpatents

    Reed, Evan J.; Armstrong, Michael R.

    2010-09-07

    Strain waves of THz frequencies can coherently generate radiation when they propagate past an interface between materials with different piezoelectric coefficients. Such radiation is of detectable amplitude and contains sufficient information to determine the time-dependence of the strain wave with unprecedented subpicosecond, nearly atomic time and space resolution.

  11. Properties of Cerium Containing Lead Free Solder

    NASA Astrophysics Data System (ADS)

    Xie, Huxiao

    With increasing concerns of the intrinsic toxicity of lead (Pb) in electronics, a series of tin (Sn) based alloys involving silver (Ag) and copper (Cu) have been proposed as replacements for Pb-Sn solder and widely accepted by industry. However, they have a higher melting point and often exhibit poorer damage tolerance than Pb-Sn alloys. Recently, a new class of alloys with trace amount of rare-earth (RE) elements has been discovered and investigated. In previous work from Prof. Chawla's group, it has been shown that cerium (Ce)-based Pb-free solder are less prone to oxidation and Sn whiskering, and exhibit desirable attributes of microstructural refinement and enhanced ductility relative to lanthanum (La)-based Sn-3.9Ag-0.7Cu (SAC) alloy. Although the formation of RESn3 was believed to be directly responsible for the enhanced ductility in RE-containing SAC solder by allowing microscopic voids to nucleate throughout the solder volume, this cavitation-based mechanism needs to be validated experimentally and numerically. Additionally, since the previous study has exhibited the realistic feasibility of Ce-based SAC lead-free solder alloy as a replacement to conventional SAC alloys, in this study, the proposed objective focuses on the in in-depth understanding of mechanism of enhanced ductility in Ce-based SAC alloy and possible issues associated with integration of this new class of solder into electronic industry, including: (a) study of long-term thermal and mechanical stability on industrial metallization, (b) examine the role of solder volume and wetting behavior of the new solder, relative to Sn-3.9Ag-0.7Cu alloys, (c) conduct experiments of new solder alloys in the form of mechanical shock and electromigration. The research of this new class alloys will be conducted in industrially relevant conditions, and the results would serve as the first step toward integration of these new, next generation solders into the industry.

  12. A FEM-based method to determine the complex material properties of piezoelectric disks.

    PubMed

    Pérez, N; Carbonari, R C; Andrade, M A B; Buiochi, F; Adamowski, J C

    2014-08-01

    Numerical simulations allow modeling piezoelectric devices and ultrasonic transducers. However, the accuracy in the results is limited by the precise knowledge of the elastic, dielectric and piezoelectric properties of the piezoelectric material. To introduce the energy losses, these properties can be represented by complex numbers, where the real part of the model essentially determines the resonance frequencies and the imaginary part determines the amplitude of each resonant mode. In this work, a method based on the Finite Element Method (FEM) is modified to obtain the imaginary material properties of piezoelectric disks. The material properties are determined from the electrical impedance curve of the disk, which is measured by an impedance analyzer. The method consists in obtaining the material properties that minimize the error between experimental and numerical impedance curves over a wide range of frequencies. The proposed methodology starts with a sensitivity analysis of each parameter, determining the influence of each parameter over a set of resonant modes. Sensitivity results are used to implement a preliminary algorithm approaching the solution in order to avoid the search to be trapped into a local minimum. The method is applied to determine the material properties of a Pz27 disk sample from Ferroperm. The obtained properties are used to calculate the electrical impedance curve of the disk with a Finite Element algorithm, which is compared with the experimental electrical impedance curve. Additionally, the results were validated by comparing the numerical displacement profile with the displacements measured by a laser Doppler vibrometer. The comparison between the numerical and experimental results shows excellent agreement for both electrical impedance curve and for the displacement profile over the disk surface. The agreement between numerical and experimental displacement profiles shows that, although only the electrical impedance curve is

  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. Performance of tonpilz transducers with segmented piezoelectric stacks using materials with high electromechanical coupling coefficient.

    PubMed

    Thompson, Stephen C; Meyer, Richard J; Markley, Douglas C

    2014-01-01

    Tonpilz acoustic transducers for use underwater often include a stack of piezoelectric material pieces polarized along the length of the stack and having alternating polarity. The pieces are interspersed with electrodes, bonded together, and electrically connected in parallel. The stack is normally much shorter than a quarter wavelength at the fundamental resonance frequency so that the mechanical behavior of the transducer is not affected by the segmentation. When the transducer bandwidth is less than a half octave, as has conventionally been the case, for example, with lead zirconate titanate (PZT) material, stack segmentation has no significant effect on the mechanical behavior of the device in its normal operating band near the fundamental resonance. However, when a high coupling coefficient material such as lead magnesium niobate-lead titanate (PMN-PT) is used to achieve a wider bandwidth with the tonpilz, the performance difference between a segmented stack and a similar piezoelectric section with electrodes only at the two ends can be significant. This paper investigates the effects of stack segmentation on the performance of wideband underwater tonpilz acoustic transducers. Included is a discussion of a particular tonpilz transducer design using single crystal piezoelectric material with high coupling coefficient compared with a similar design using more traditional PZT ceramics. PMID:24437755

  15. Achieving synchronization with active hybrid materials: Coupling self-oscillating gels and piezoelectric films

    NASA Astrophysics Data System (ADS)

    Yashin, Victor V.; Levitan, Steven P.; Balazs, Anna C.

    Our goal is to develop materials that compute by using non-linear oscillating chemical reactions to perform spatio-temporal recognition tasks. The material of choice is a polymer gel undergoing the oscillatory Belousov-Zhabotinsky reaction. The novelty of our approach is in employing hybrid gel-piezoelectric micro-electro-mechanical systems (MEMS) to couple local chemo-mechanical oscillations over long distances by electrical connection. Our modeling revealed that (1) interaction between the MEMS units is sufficiently strong for synchronization; (2) the mode of synchronization depends on the number of units, type of circuit connection (serial of parallel), and polarity of the units; (3) each mode has a distinctive pattern in phase of oscillations and generated voltage. The results indicate feasibility of using the hybrid gel-piezoelectric MEMS for oscillator based unconventional computing.

  16. 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.

  17. Design and analysis of a piezoelectric material based touch screen with additional pressure and its acceleration measurement functions

    NASA Astrophysics Data System (ADS)

    Chu, Xiang-Cheng; Liu, Jia-Yi; Gao, Ren-Long; Chang, Jie; Li, Long-Tu

    2013-12-01

    Touch screens are becoming more and more prevalent in everyday environments due to their convenience and humanized operation. In this paper, a piezoelectric material based touch screen is developed and investigated. Piezoelectric ceramics arrayed under the touch panel at the edges or corners are used as tactile sensors to measure the touch positioning point similarly to conventional touch screens. However, additional touch pressure and its acceleration performance can also be obtained to obtain a higher-level human-machine interface. The piezoelectric ceramics can also be added to a traditional touch screen structure, or they can be used independently to construct a novel touch screen with a high light transmittance approach to a transparent glass. The piezoelectric ceramics were processed from PZT piezoelectric ceramic powder into a round or rectangular shape. According to the varied touch position and physical press strength of a finger, or even a gloved hand or fingernail, the piezoelectric tactile sensors will have different output voltage responses. By calculating the ratio of different piezoelectric tactile sensors’ responses and summing up all piezoelectric tactile sensors’ output voltages, the touch point position, touch pressure and touch force acceleration can be detected. A prototype of such a touch screen is manufactured and its position accuracy, touch pressure and response speed are measured in detail. The experimental results show that the prototype has many advantages such as high light transmittance, low energy cost and high durability.

  18. Green's functions of one-dimensional quasicrystal bi-material with piezoelectric effect

    NASA Astrophysics Data System (ADS)

    Zhang, Liangliang; Wu, Di; Xu, Wenshuai; Yang, Lianzhi; Ricoeur, Andreas; Wang, Zhibin; Gao, Yang

    2016-09-01

    Based on the Stroh formalism of one-dimensional quasicrystals with piezoelectric effect, the problems of an infinite plane composed of two different quasicrystal half-planes are taken into account. The solutions of the internal and interfacial Green's functions of quasicrystal bi-material are obtained. Moreover, numerical examples are analyzed for a quasicrystal bi-material subjected to line forces or line dislocations, showing the contour maps of the coupled fields. The impacts of changing material constants on the coupled field components are investigated.

  19. Structure and electrical properties of 0.80 Na0.5 Bi0.5 TiO3-0.16 K0.5 Bi0.5 TiO3-0.04 BaTiO3 lead-free piezoelectric ceramics

    NASA Astrophysics Data System (ADS)

    Aravinth, K.; Muneeswaran, M.; Babu, G. Anandha; Giridharan, N. V.; Ramasamy, P.

    2016-05-01

    Lead free pervoskite 0.80 Na0.5 Bi0.5 TiO3-0.16 K0.5 Bi0.5 TiO3-0.04 BaTiO3 (NKBBT) ceramics were fabricated via conventional solid state processing technique sintered at 1200 °C and their crystal structures and electrical properties were systematically studied. Structure of the prepared NKBBT ceramics was confirmed by Powder X-ray diffraction analysis. The dependence of dielectric constant on temperature for various frequencies (100 Hz-100 KHz) has been determined. The diffuse transition is observed in the variation of dielectric constant and it provides evidence for the relaxor characteristics. The ferroelectric response of the NKBBT ceramics with different frequency was studied. Polarisation electric field hysteresis loops revealed that the remnant polarization is 6.88 µC/cm2 and coercive electric field is 66.42 kV/cm.

  20. Investigating the frequency spectrum of mechanical quality factor for piezoelectric materials based on phenomenological model

    NASA Astrophysics Data System (ADS)

    Shi, Weijia; Zhao, Hui; Ma, Jie; Yao, Yu; Uchino, Kenji

    2015-10-01

    Heat generation due to losses restricts piezoelectric materials from maintaining a high power density, which will further limit the miniaturization of piezoelectric devices. As an evaluation index of the loss level, the mechanical quality factor shows an opposite tendency with losses. The mechanical quality factor should therefore be evaluated. By new methods to determine the mechanical quality factor, the highest mechanical quality factor has been discovered within the working bandwidth other than the resonance and antiresonance frequencies, which is almost double the value at the resonance. In this study, the prime determinant of the maximum value has been experimentally investigated on the basis of the phenomenological model of the admittance phase. The investigation experimentally infers that the change in the tendency of the phase leads to the appearance of the maximum value. Thus, the new phenomenon is experimentally explained for the first time.

  1. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2015-03-01

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

  3. 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.

  4. Using iridium films to compensate for piezo-electric materials processing stresses in adjustable x-ray optics

    NASA Astrophysics Data System (ADS)

    Ames, A.; Bruni, R.; Cotroneo, V.; Johnson-Wilke, R.; Kester, T.; Reid, P.; Romaine, S.; Tolier-McKinstry, S.; Wilke, R. H. T.

    2015-09-01

    Adjustable X-ray optics represent a potential enabling technology for simultaneously achieving large effective area and high angular resolution for future X-ray Astronomy missions. The adjustable optics employ a bimorph mirror composed of a thin (1.5 μm) film of piezoelectric material deposited on the back of a 0.4 mm thick conical mirror segment. The application of localized electric fields in the piezoelectric material, normal to the mirror surface, result in localized deformations in mirror shape. Thus, mirror fabrication and mounting induced figure errors can be corrected, without the need for a massive reaction structure. With this approach, though, film stresses in the piezoelectric layer, resulting from deposition, crystallization, and differences in coefficient of thermal expansion, can distort the mirror. The large relative thickness of the piezoelectric material compared to the glass means that even 100MPa stresses can result in significant distortions. We have examined compensating for the piezoelectric processing related distortions by the deposition of controlled stress chromium/iridium films on the front surface of the mirror. We describe our experiments with tuning the product of the chromium/iridium film stress and film thickness to balance that resulting from the piezoelectric layer. We also evaluated the repeatability of this deposition process, and the robustness of the iridium coating.

  5. 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%).

  6. Fin-buffet alleviation via distributed piezoelectric actuators: materials qualification program

    NASA Astrophysics Data System (ADS)

    Zaglauer, Helmut W.; Duerr, Johannes K.; Floeth, Erik; Ihler, Elmar; Herold-Schmidt, Ursula; Dittrich, Kay W.; Simpson, John; Becker, Juergen

    1999-07-01

    One of the most innovative concepts for active fin-buffet alleviation in vertical tail aircraft is the use of piezoelectric patch actuators distributed across the tail surface to actively induce a counter-strain into the structure. This concept involves the development of a novel material compound structure consisting of a fiber-composite aircraft skin, a ceramic patch actuator and the bonding layer between both components. This actively controllable structure has to provide enough authority to dampen the fin- buffet vibrations. It also has to function reliably during long-term aircraft operation under severe mechanical and environmental load conditions.

  7. Targeted basic studies of ferroelectric and ferroelastic materials for piezoelectric transducer applications

    NASA Astrophysics Data System (ADS)

    Cross, L. E.; Newnham, R. E.; Barsch, G. R.; Biggers, J. V.

    1983-03-01

    The work reported covers the fifth and final year of the program of targeted basic studies of ferroelectric and ferroelastic materials for piezoelectric transducer applications. Major achievements include: the development of a physical approach to understanding active composites, leading to the development of several new families of PZT, polymer piezoelectric composites for hydrophone application. These are new advances in the phenomenology and microscopic theory of electrostriction, and the evolution of a new family of high strain ferroelectric relaxor materials for practical application. New basic understanding of the polarization mechanisms in ferroelectric relaxors has been aided by the study of order disorder of the cation arrangement in lead scandium tantalate, and the results correlate well with studies of relaxor behavior, and of shape memory effects in PLZT ceramics. Low temperature studies on pure and doped PZTs have given the first clear indication of the intrinsic (averaged) single domain in response and correlate exceedingly well with earlier phenomenological theory. Crystal growth and ceramic processing studies have developed hand in hand with program needs providing new forms of conventional materials, new grain oriented structures and single crystals.

  8. 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.

  9. Development of lead-free solders for hybrid microcircuits

    SciTech Connect

    Hosking, F.M.; Vianco, P.T.; Frear, D.R.; Robinson, D.G.

    1996-01-01

    Extensive work has been conducted by industry to develop lead-free solders for electronics applications. The driving force behind this effort is pressure to ban or tax the use of lead-bearing solders. There has been further interest to reduce the use of hazardous chemical cleaners. Lead-free soldering and low-residue, ``no clean`` assembly processing are being considered as solutions to these environmental issues. Most of the work has been directed toward commercial and military printed wiring board (PWB) technology, although similar problems confront the hybrid microcircuit (HMC) industry, where the development of lead-free HMC solders is generally lagging. Sandia National Laboratories is responsible for designing a variety of critical, high reliability hybrid components for radars. Sandia has consequently initiated a project, as part of its Environmentally Conscious Manufacturing program, to develop low-residue, lead-free soldering for HMCs. This paper discusses the progress of that work.

  10. Piezoelectric properties of polyamide 11/NaNbO3 nanowire composites

    NASA Astrophysics Data System (ADS)

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

    2012-10-01

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

  11. Piezoelectric Nanoindentation

    SciTech Connect

    Rar, Andrei; Pharr, George Mathews; Oliver, Warren C.; Karapetian, Edgar; Kalinin, Sergei V

    2006-01-01

    Piezoelectric nanoindentation (PNI) has been developed to quantitatively address electromechanical coupling and pressure-induced dynamic phenomena in ferroelectric materials on the nanoscale. In PNI, an oscillating voltage is applied between the back side of the sample and the indenter tip, and the first harmonic of bias-induced surface displacement at the area of indenter contact is detected. PNI is implemented using a standard nanoindentation system equipped with a continuous stiffness measurement system. The piezoresponse of polycrystalline lead zirconate titanate (PZT) and BaTiO{sub 3} piezoceramics was studied during a standard nanoindentation experiment. For PZT, the response was found to be load independent, in agreement with theoretical predictions. In polycrystalline barium titanate, a load dependence of the piezoresponse was observed. The potential of piezoelectric nanoindentation for studies of phase transitions and local structure-property relations in piezoelectric materials is discussed.

  12. 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.

  13. Identification of combustible material with piezoelectric crystal sensor array using pattern-recognition techniques.

    PubMed

    He, X W; Xing, W L; Fang, Y H

    1997-11-01

    A promising way of increasing the selectivity and sensitivity of gas sensors is to treat the signals from a number of different gas sensors with pattern recognition (PR) method. A gas sensor array with seven piezoelectric crystals each coated with a different partially selective coating material was constructed to identify four kinds of combustible materials which generate smoke containing different components. The signals from the sensors were analyzed with both conventional multivariate analysis, stepwise discriminant analysis (SDA), and artificial neural networks (ANN) models. The results show that the predictions were even better with ANN models. In our experiment, we have reported a new method for training data selection, 'training set stepwise expending method' to solve the problem that the network can not converge at the beginning of the training. We also discussed how the parameters of neural networks, learning rate eta, momentum term alpha and few bad training data affect the performance of neural networks. PMID:18966950

  14. Large-scale computational simulation for optimal design of curved piezoelectric actuator using composite material

    NASA Astrophysics Data System (ADS)

    Chung, Soon Wan; Hwang, In Seong; Kim, Seung Jo

    2004-07-01

    In this paper, the electromechanical displacements of curved piezoelectric actuators with laminated composite material are calculated using high performance computing technology, and the optimal configuration of composite curved actuator is proposed. To predict the pre-stress in the device due to the mismatch in coefficients of thermal expansion, carbon-epoxy and glass-epoxy as well as PZT ceramic are numerically modeled by using hexahedral solid elements. Because the modeling of these thin layers causes the numbers of degree of freedom to increase, large-scale structural analyses are performed through the PEGASUS supercomputer which is composed of 400 Intel Xeon CPUs. In the first stage, the curved shape of the actuator and the internal stress in each layer are obtained by the cured curvature analysis. Subsequently, the displacement due to the piezoelectric force by an applied voltage is also calculated and the performance of composite curved actuator is investigated by comparing the displacements according to the configuration of the actuator. To consider the finite deformation in the first stage and include the pre-stress in each layer in the second analysis stage, nonlinear finite element analyses will be carried out. The thickness and the elastic constants of laminated composite are chosen as design factors.

  15. Piezoelectrochemical effect: Mechanical energy induced redox reaction in aqueous solutions through vibrating piezoelectric materials

    NASA Astrophysics Data System (ADS)

    Hong, Kuang-Sheng

    We propose a phenomenon of piezoelectrochemical (PZEC) effect for the direct conversion of mechanical energy to chemical energy. This phenomenon is further applied for generating hydrogen and oxygen via direct water decomposition by means of as-synthesized piezoelectric quartz (SiO2) nano-rods, ZnO microfibers, and BaTiO3 microdendrites. The materials are vibrated with ultrasonic waves leading to a strain-induced electric charge development on their surface. With sufficient electric potential, the strained piezoelectric materials in water triggered the redox reaction of water to produce hydrogen and oxygen gases. All materials have indicated a well response to the external mechanical vibration to drive the desired chemical reactions. ZnO fibers under ultrasonic vibrations showed a stoichiometric ratio of H 2/O2 (2:1) initial gas production from pure water. The efficiency of the piezoelectrochemical effect was calculated by ratio of the chemical energy output over the mechanical energy input of the system. The study of piezoelectrochemical effect is further applied to the environmental cleaning technology. Accordingly, a dissolved orange dye (AO7) was decomposed via mechanical driving force by using BaTiO3 microdendrites. Kinetic details of the dye decomposition through piezoelectrochemical effect were investigated. In addition, the piezoelectrochemical effect was proposed to the implication of tectonic hydrogen in geological systems providing insights of hydrogen generation in active fault zones. The tectonic hydrogen produced through PZEC effect could be a sustainable energy source for subsurface microbial community. This study provides a simple and cost-effective technology for generating hydrogen fuels as well as environmental cleaning by scavenging energy wastes such as noise or stray vibrations from the environment. This new piezoelectrochemical effect may have potential implications in solving the challenging energy and environmental issues that we are facing

  16. A novel in situ device based on a bionic piezoelectric actuator to study tensile and fatigue properties of bulk materials

    NASA Astrophysics Data System (ADS)

    Wang, Shupeng; Zhang, Zhihui; Ren, Luquan; Zhao, Hongwei; Liang, Yunhong; Zhu, Bing

    2014-06-01

    In this work, a miniaturized device based on a bionic piezoelectric actuator was developed to investigate the static tensile and dynamic fatigue properties of bulk materials. The device mainly consists of a bionic stepping piezoelectric actuator based on wedge block clamping, a pair of grippers, and a set of precise signal test system. Tensile and fatigue examinations share a set of driving system and a set of signal test system. In situ tensile and fatigue examinations under scanning electron microscope or metallographic microscope could be carried out due to the miniaturized dimensions of the device. The structure and working principle of the device were discussed and the effects of output difference between two piezoelectric stacks on the device were theoretically analyzed. The tensile and fatigue examinations on ordinary copper were carried out using this device and its feasibility was verified through the comparison tests with a commercial tensile examination instrument.

  17. A novel in situ device based on a bionic piezoelectric actuator to study tensile and fatigue properties of bulk materials

    SciTech Connect

    Wang, Shupeng; Zhang, Zhihui Ren, Luquan; Liang, Yunhong; Zhao, Hongwei; Zhu, Bing

    2014-06-15

    In this work, a miniaturized device based on a bionic piezoelectric actuator was developed to investigate the static tensile and dynamic fatigue properties of bulk materials. The device mainly consists of a bionic stepping piezoelectric actuator based on wedge block clamping, a pair of grippers, and a set of precise signal test system. Tensile and fatigue examinations share a set of driving system and a set of signal test system. In situ tensile and fatigue examinations under scanning electron microscope or metallographic microscope could be carried out due to the miniaturized dimensions of the device. The structure and working principle of the device were discussed and the effects of output difference between two piezoelectric stacks on the device were theoretically analyzed. The tensile and fatigue examinations on ordinary copper were carried out using this device and its feasibility was verified through the comparison tests with a commercial tensile examination instrument.

  18. A novel in situ device based on a bionic piezoelectric actuator to study tensile and fatigue properties of bulk materials.

    PubMed

    Wang, Shupeng; Zhang, Zhihui; Ren, Luquan; Zhao, Hongwei; Liang, Yunhong; Zhu, Bing

    2014-06-01

    In this work, a miniaturized device based on a bionic piezoelectric actuator was developed to investigate the static tensile and dynamic fatigue properties of bulk materials. The device mainly consists of a bionic stepping piezoelectric actuator based on wedge block clamping, a pair of grippers, and a set of precise signal test system. Tensile and fatigue examinations share a set of driving system and a set of signal test system. In situ tensile and fatigue examinations under scanning electron microscope or metallographic microscope could be carried out due to the miniaturized dimensions of the device. The structure and working principle of the device were discussed and the effects of output difference between two piezoelectric stacks on the device were theoretically analyzed. The tensile and fatigue examinations on ordinary copper were carried out using this device and its feasibility was verified through the comparison tests with a commercial tensile examination instrument. PMID:24985848

  19. Exploring Coulomb interaction in piezoelectric materials for assisting the laser cooling of solids

    NASA Astrophysics Data System (ADS)

    Hassani Nia, Iman; Mohseni, Hooman

    2014-02-01

    Realization of anti-Stokes cooling requires high enough photon extraction efficiency as well as quantum efficiency, making the implementation of this technique extremely difficult for semiconductors. Here, for the first time, we demonstrate that the Coulomb interaction between photogenerated electron-hole pairs in strong piezoelectric materials such as GaN/InGaN quantum wells could assist laser cooling. By comparing to the cavity back-action mechanism, we also explain how this process depends upon laser detuning with respect to bandgap. To demonstrate the advantage of this method even further, we present simulations by using experimentally reported parameters of GaN and In0.15Ga0.85N, in order to conclude that the net cooling is indeed possible even with current III-nitride growth technology.

  20. 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.

  1. Achieving synchronization with active hybrid materials: Coupling self-oscillating gels and piezoelectric films

    NASA Astrophysics Data System (ADS)

    Yashin, Victor V.; Levitan, Steven P.; Balazs, Anna C.

    2015-06-01

    Lightweight, deformable materials that can sense and respond to human touch and motion can be the basis of future wearable computers, where the material itself will be capable of performing computations. To facilitate the creation of “materials that compute”, we draw from two emerging modalities for computation: chemical computing, which relies on reaction-diffusion mechanisms to perform operations, and oscillatory computing, which performs pattern recognition through synchronization of coupled oscillators. Chemical computing systems, however, suffer from the fact that the reacting species are coupled only locally; the coupling is limited by diffusion as the chemical waves propagate throughout the system. Additionally, oscillatory computing systems have not utilized a potentially wearable material. To address both these limitations, we develop the first model for coupling self-oscillating polymer gels to a piezoelectric (PZ) micro-electro-mechanical system (MEMS). The resulting transduction between chemo-mechanical and electrical energy creates signals that can be propagated quickly over long distances and thus, permits remote, non-diffusively coupled oscillators to communicate and synchronize. Moreover, the oscillators can be organized into arbitrary topologies because the electrical connections lift the limitations of diffusive coupling. Using our model, we predict the synchronization behavior that can be used for computational tasks, ultimately enabling “materials that compute”.

  2. Achieving synchronization with active hybrid materials: Coupling self-oscillating gels and piezoelectric films

    PubMed Central

    Yashin, Victor V.; Levitan, Steven P.; Balazs, Anna C.

    2015-01-01

    Lightweight, deformable materials that can sense and respond to human touch and motion can be the basis of future wearable computers, where the material itself will be capable of performing computations. To facilitate the creation of “materials that compute”, we draw from two emerging modalities for computation: chemical computing, which relies on reaction-diffusion mechanisms to perform operations, and oscillatory computing, which performs pattern recognition through synchronization of coupled oscillators. Chemical computing systems, however, suffer from the fact that the reacting species are coupled only locally; the coupling is limited by diffusion as the chemical waves propagate throughout the system. Additionally, oscillatory computing systems have not utilized a potentially wearable material. To address both these limitations, we develop the first model for coupling self-oscillating polymer gels to a piezoelectric (PZ) micro-electro-mechanical system (MEMS). The resulting transduction between chemo-mechanical and electrical energy creates signals that can be propagated quickly over long distances and thus, permits remote, non-diffusively coupled oscillators to communicate and synchronize. Moreover, the oscillators can be organized into arbitrary topologies because the electrical connections lift the limitations of diffusive coupling. Using our model, we predict the synchronization behavior that can be used for computational tasks, ultimately enabling “materials that compute”. PMID:26105979

  3. A magnetic-piezoelectric smart material-structure utilizing magnetic force interaction to optimize the sensitivity of current sensing

    NASA Astrophysics Data System (ADS)

    Yeh, Po-Chen; Chung, Tien-Kan; Lai, Chen-Hung; Wang, Chieh-Min

    2016-01-01

    This paper presents a magnetic-piezoelectric smart material-structure using a novel magnetic-force-interaction approach to optimize the sensitivity of conventional piezoelectric current sensing technologies. The smart material-structure comprises a CuBe-alloy cantilever beam, a piezoelectric PZT sheet clamped to the fixed end of the beam, and an NdFeB permanent magnet mounted on the free end of the beam. When the smart material-structure is placed close to an AC conductor, the magnet on the beam of the smart structure experiences an alternating magnetic attractive and repulsive force produced by the conductor. Thus, the beam vibrates and subsequently generates a strain in the PZT sheet. The strain produces a voltage output because of the piezoelectric effect. The magnetic force interaction is specifically enhanced through the optimization approach (i.e., achieved by using SQUID and machining method to reorient the magnetization to different directions to maximize the magnetic force interaction). After optimizing, the beam's vibration amplitude is significantly enlarged and, consequently, the voltage output is substantially increased. The experimental results indicated that the smart material-structure optimized by the proposed approach produced a voltage output of 4.01 Vrms with a sensitivity of 501 m Vrms/A when it was placed close to a conductor with a current of 8 A at 60 Hz. The optimized voltage output and sensitivity of the proposed smart structure were approximately 316 % higher than those (1.27 Vrms with 159 m Vrms/A) of representative piezoelectric-based current sensing technologies presented in other studies. These improvements can significantly enable the development of more self-powered wireless current sensing applications in the future.

  4. 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.

  5. Preparation, crystal structure and enhanced bipolar response of 0.90BLNT-0.10BCT lead-free piezoceramics

    NASA Astrophysics Data System (ADS)

    Pal, Vijayeta; Kumar, A.; Thakur, O. P.; Dwivedi, R. K.

    2016-05-01

    In the present work, a solid solution of lead free 0.90[(Bi0.96La0.04)0.5Na0.5TiO3]-0.10(Ba0.90Ca0.10TiO3] (abbreviated as 0.90BLNT-0.10BCT) piezoceramics has been synthesized by semi-wet technique. X-ray diffraction pattern confirms the phase formation. Rietveld refinement of XRD data demonstrates the coexistence of rhombhohedral (R3c) + tetragonal (P4mm) phase at room temperature. Raman spectrum is also support the above analysis. A large enhancement in bipolar strain of 0.12 % and calculated normalized strain, d*33 (defined as Smax/Emax) ~ 265 pm/V at 40kV/cm has been observed for this composition as compared to pure BLNT specimen, which make possible it as a potential lead-free candidates for piezoelectric applications.

  6. 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.

  7. 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)

  8. 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

  9. Silver nanosintering: a lead-free alternative to soldering

    NASA Astrophysics Data System (ADS)

    Maruyama, Minoru; Matsubayashi, Ryo; Iwakuro, Hiroaki; Isoda, Seiji; Komatsu, Teruo

    2008-07-01

    We propose a lead-free silver paste as a replacement for a high-temperature lead-rich solder used for electronics. The pastes tested here contain a small amount of solvent, but primarily consist of silver powder and alkoxide-passivated silver nanoparticles that undergo nanosintering when heated. The pastes were used to connect silicon diode chips to copper bases at 350°C in nitrogen ambient without external pressure. The resulting diode packages had electrical and thermal properties about equal to those with lead-solder joints. The mechanical strengths also were comparable to the lead joint. These properties make this nanosilver paste the first viable lead-free alternative to a lead solder.

  10. Targeted basic studies of ferroelectric and ferroelastic materials for piezoelectric transducer applications

    NASA Astrophysics Data System (ADS)

    Cross, L. E.; Newnham, R. E.; Barsch, G. R.; Biggers, J. V.

    1983-03-01

    The report delineates the new progress made in the fifth and final year and discusses the major accomplishments of the full five year program both in the basic science and in the spin off to practical transducer applications. Possible new areas of study which are suggested by the present studies are briefly reported. Major achievements include the development of a physical approach to understanding active composites, leading to the development of several new families of PZT:polymer piezoelectric composites for hydrophone application. New advances in the phenomenology and microscopic theory of electrostriction, and the evolution of a new family of high strain ferroelectric relaxor materials for practical application. New basic understanding of the polarization mechanisms in ferroelectric relaxors has been aided by the study of order-disorder of the cation arrangement in lead scandium tantalate, and the results correlate well with studies of relaxor behavior, and of shape memory effects in PLZT ceramics. Low temperature studies on pure and doped PZTs have given the first clear indication of the intrinsic (averaged) single domain response and correlate exceedingly well with earlier phenomenological theory. Crystal growth and ceramic processing studies have developed hand-in-hand with program needs providing new forms of conventional materials, new grain oriented structures and single crystals.

  11. Characterization of Full Set Material Constants and Their Temperature Dependence for Piezoelectric Materials Using Resonant Ultrasound Spectroscopy

    PubMed Central

    Tang, Liguo; Cao, Wenwu

    2016-01-01

    During the operation of high power electromechanical devices, a temperature rise is unavoidable due to mechanical and electrical losses, causing the degradation of device performance. In order to evaluate such degradations using computer simulations, full matrix material properties at elevated temperatures are needed as inputs. It is extremely difficult to measure such data for ferroelectric materials due to their strong anisotropic nature and property variation among samples of different geometries. Because the degree of depolarization is boundary condition dependent, data obtained by the IEEE (Institute of Electrical and Electronics Engineers) impedance resonance technique, which requires several samples with drastically different geometries, usually lack self-consistency. The resonant ultrasound spectroscopy (RUS) technique allows the full set material constants to be measured using only one sample, which can eliminate errors caused by sample to sample variation. A detailed RUS procedure is demonstrated here using a lead zirconate titanate (PZT-4) piezoceramic sample. In the example, the complete set of material constants was measured from room temperature to 120 °C. Measured free dielectric constants ε11T and ε33T were compared with calculated ones based on the measured full set data, and piezoelectric constants d15 and d33 were also calculated using different formulas. Excellent agreement was found in the entire range of temperatures, which confirmed the self-consistency of the data set obtained by the RUS. PMID:27168336

  12. Characterization of Full Set Material Constants and Their Temperature Dependence for Piezoelectric Materials Using Resonant Ultrasound Spectroscopy.

    PubMed

    Tang, Liguo; Cao, Wenwu

    2016-01-01

    During the operation of high power electromechanical devices, a temperature rise is unavoidable due to mechanical and electrical losses, causing the degradation of device performance. In order to evaluate such degradations using computer simulations, full matrix material properties at elevated temperatures are needed as inputs. It is extremely difficult to measure such data for ferroelectric materials due to their strong anisotropic nature and property variation among samples of different geometries. Because the degree of depolarization is boundary condition dependent, data obtained by the IEEE (Institute of Electrical and Electronics Engineers) impedance resonance technique, which requires several samples with drastically different geometries, usually lack self-consistency. The resonant ultrasound spectroscopy (RUS) technique allows the full set material constants to be measured using only one sample, which can eliminate errors caused by sample to sample variation. A detailed RUS procedure is demonstrated here using a lead zirconate titanate (PZT-4) piezoceramic sample. In the example, the complete set of material constants was measured from room temperature to 120 °C. Measured free dielectric constants and  were compared with calculated ones based on the measured full set data, and piezoelectric constants d15 and d33 were also calculated using different formulas. Excellent agreement was found in the entire range of temperatures, which confirmed the self-consistency of the data set obtained by the RUS. PMID:27168336

  13. 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.

  14. Piezoelectric enhancement under negative pressure.

    PubMed

    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

  15. Hybrid thermoelectric piezoelectric generator

    NASA Astrophysics Data System (ADS)

    Montgomery, D. S.; Hewitt, C. A.; Carroll, D. L.

    2016-06-01

    This work presents an integration of flexible thermoelectric and piezoelectric materials into a single device structure. This device architecture overcomes several prohibitive issues facing the combination of traditional thermoelectric and piezoelectric generators, while optimizing performance of the combined power output. The structure design uses a carbon nanotube/polymer thin film as a flexible thermoelectric generator that doubles as an electrode on a piezoelectric generator made of poly(vinylidene fluoride). An example 2 × 2 array of devices is shown to generate 89% of the maximum thermoelectric power, and provide 5.3 times more piezoelectric voltage when compared with a traditional device.

  16. Experimental verification of new configurations in the piezoelectric photothermal spectroscopy of semiconductor materials

    NASA Astrophysics Data System (ADS)

    Bychto, L.; Maliński, M.; Zakrzewski, J.; Łegowski, S.; Męczyńska, H.

    2004-10-01

    This paper presents the analysis of two experimental configurations applied in the piezoelectric spectroscopy method. The first configuration called `rear' is normally used in the field of piezoelectric spectroscopy. The second configuration called `front' is a new configuration analyzed by authors. In this paper both advantages and disadvantages of both configurations are described. In this paper both theoretical and experimental spectra measured in these two configurations are presented and compared.

  17. Energy harvesting based on piezoelectric Ericsson cycles in a piezoceramic material

    NASA Astrophysics Data System (ADS)

    Zhang, B.; Ducharne, B.; Guyomar, D.; Sebald, G.

    2013-09-01

    The possibility of recycling ambient energies with electric generators instead of using batteries with limited life spans has stimulated important research efforts over the past years. The integration of such generators into mainly autonomous low-power systems, for various industrial or domestic applications is envisioned. In particular, the present work deals with energy harvesting from mechanical vibrations. It is shown here that direct piezoelectric energy harvesting (short circuiting on an adapted resistance, for example) leads to relatively weak energy levels that are insufficient for an industrial development. By coupling an electric field and mechanical excitation on Ericsson-based cycles, the amplitude of the harvested energy can be highly increased, and can reach a maximum close to 100 times its initial value. To obtain such a gain, one needs to employ high electrical field levels (high amplitude, high frequency), which induce a non-linearity through the piezoceramic. A special dynamic hysteresis model has been developed to correctly take into account the material properties, and to provide a real estimation of the harvested energy. A large number of theoretical predictions and experimental results have been compared and are discussed herein, in order to validate the proposed solution.

  18. Two-dimensional fracture analysis of piezoelectric material based on the scaled boundary node method

    NASA Astrophysics Data System (ADS)

    Shen-Shen, Chen; Juan, Wang; Qing-Hua, Li

    2016-04-01

    A scaled boundary node method (SBNM) is developed for two-dimensional fracture analysis of piezoelectric material, which allows the stress and electric displacement intensity factors to be calculated directly and accurately. As a boundary-type meshless method, the SBNM employs the moving Kriging (MK) interpolation technique to an approximate unknown field in the circumferential direction and therefore only a set of scattered nodes are required to discretize the boundary. As the shape functions satisfy Kronecker delta property, no special techniques are required to impose the essential boundary conditions. In the radial direction, the SBNM seeks analytical solutions by making use of analytical techniques available to solve ordinary differential equations. Numerical examples are investigated and satisfactory solutions are obtained, which validates the accuracy and simplicity of the proposed approach. Project supported by the National Natural Science Foundation of China (Grant Nos. 11462006 and 21466012), the Foundation of Jiangxi Provincial Educational Committee, China (Grant No. KJLD14041), and the Foundation of East China Jiaotong University, China (Grant No. 09130020).

  19. 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.

  20. 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

    2016-03-01

    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. PMID:26868967

  1. Ultrasonic transducers based on undoped lead-free (K0.5Na0.5)NbO3 ceramics.

    PubMed

    Bah, Micka; Giovannelli, Fabien; Schoenstein, Frederic; Brosseau, Christophe; Deschamps, Jean-Robert; Dorvaux, Frédéric; Haumesser, Lionel; Le Clezio, Emmanuel; Monot-Laffez, Isabelle

    2015-12-01

    Lead zirconate titanate (PZT) ceramics are the dominant piezoelectric elements for non-destructive evaluation (NDE) and ultrasonic transducers devices. However, the presence of lead content may impose the scientific community to develop lead-free ceramics, concerning human health and environmental safety. During the past ten years, many contributions have highlighted the potential properties of complex compositions like LiNbO3, LiTaO3 and LiSbO3 in the lead-free (K0.5Na0.5)NbO3 KNN system. In this context, for the first time, the practical applications and the effectiveness of simply undoped (K0.5Na0.5)NbO3 (KNN) ceramics are investigated. KNN powder is prepared by conventional solid state mixed oxide route. Ceramics of this material are prepared using conventional sintering (CS) and spark plasma sintering (SPS). Thickness coupling factor kt of 44-46%, planar coupling factor kp of 29-45%, relative permittivity at constant strain ε33,r(S) of 125-243 and acoustic impedance Z of 23-30 MRay are obtained for these two kinds of undoped KNN ceramics. Both ceramics are used to build single-element ultrasonic transducers. Relative bandwidth of 49-78% and insertion loss of -27 and -51dB are obtained for SPS and CS transducers, respectively. These results are suitable for use in non-destructive evaluation. The effectiveness of undoped KNN is evaluated using the KLM model, and compared to standard PZT based probe. Finally, chemical aging test of undoped KNN has demonstrated its stability in water. PMID:26117145

  2. Actuation Using Piezoelectric Materials: Application in Augmenters, Energy Harvesters, and Motors

    NASA Technical Reports Server (NTRS)

    Hasenoehrl, Jennifer

    2012-01-01

    Piezoelectric actuators are used in many manipulation, movement, and mobility applications as well as transducers and sensors. When used at the resonance frequencies of the piezoelectric stack, the actuator performs at its maximum actuation capability. In this Space Grant internship, three applications of piezoelectric actuators were investigated including hammering augmenters of rotary drills, energy harvesters, and piezo-motors. The augmenter shows improved drill performance over rotation only. The energy harvesters rely on moving fluid to convert mechanical energy into electrical power. Specific designs allow the harvesters more freedom to move, which creates more power. The motor uses the linear movement of the actuator with a horn applied to the side of a rotor to create rotational motion. Friction inhibits this motion and is to be minimized for best performance. Tests and measurements were made during this internship to determine the requirements for optimal performance of the studied mechanisms and devices.

  3. Characterizing the effects of friction liner materials on the performance of piezoelectric motors using finite element analysis

    SciTech Connect

    Gute, G.D.; Halter, S.L.

    1995-10-01

    A finite element model of a Panasonic USM-40D piezoelectric motor`s rotor was coupled with a finite element model of the motor`s friction liner/rotor so that the frictional interface could be further studied. Results from the model were used to study the affects of various friction liner material properties on motor stall torque. Statistical methods were used to determine the significant friction liner material properties and their interactions. An equation for predicting the stall torque as a function of the significant variables and their interactions was established.

  4. The importance of lead-free electronics processes

    SciTech Connect

    Meltzer, M

    1999-10-21

    The Environmental Protection Agency (EPA) is placing increased importance on reducing lead-bearing wastes. Toward this end, the EPA has proposed that reporting thresholds for the Toxic Release Inventory (TRI) be lowered to ten pounds of lead content per year. The US electronics industry is also placing a high priority on lead reduction or elimination. The Association of Connecting Electronics Industries, which is the major trade association for electronics packaging, including printed circuit (PC) board manufacturers, has launched a lead-free initiative that seeks to eliminate lead in solder, in PC board etch resists and finish coats, and as tinning for component leads. Europe and Japan are also considering various regulations that will phase out lead in the next few years. In response to EPA and electronics industry priorities, the DOE complex will soon need to address lead phase-out issues. LLNL is now developing approaches for eliminating lead from PC board etch-resist operations. LLNL is seeking funding to continue this work and to eliminate other major uses of lead in electronics operations, particularly in hot-air solder leveling as a PC board finish, and tin-lead solder for component assembly operations. LLNL seeks to take a proactive leadership role in the DOE complex with respect to the elimination of lead. The envisioned lead-elimination project will be approximately two years in length. During the first year, lead-free etch resists and finish coats will be analyzed, and the best ones identified for electronics assembly and PC board fabrication. During the second year, lead-free solders will be examined and tested for compatibility with alternative PC board finish coats. Cost avoidance opportunities resulting from lead elimination include avoided TRI reporting expenses and reduction in PC board fabrication-related wastes through implementation of more efficient fabrication processes. Integrated Safety Management considerations are also relevant. Handling

  5. Pulsed laser deposition of lead-free (Na0.5Bi0.5)1-xBaxTiO3 ferroelectric thin films with enhanced dielectric properties

    NASA Astrophysics Data System (ADS)

    Andrei, A.; Scarisoreanu, N. D.; Birjega, R.; Dinescu, M.; Stanciu, G.; Craciun, F.; Galassi, C.

    2013-08-01

    Ferroelectric lead-free (Na0.5Bi0.5)1-xBaxTiO3 thin films obtained by pulsed laser deposition have been structurally and electrically investigated for compositions, x = 0 and x = 0.06, in and out of the morphotropic phase boundary (MPB). Sodium bismuth titanate Na0.5Bi0.5TiO3 (NBT), pure or in solid solution with other materials (like BaTiO3), is considered to be the best candidate material for lead-free ferroelectric and piezoelectric applications such as actuators and nonvolatile memory devices. Bulk solid solutions with BaTiO3 (BT), (1-x)NBT-xBT (NBT-x%BT) have been investigated widely, also due to a morphotropic phase boundary (MPB) with enhanced dielectric and ferroelectric properties between a rhombohedral and a tetragonal ferroelectric phase, at x = 0.06. Nonetheless, to transpose bulk properties to NBT-BT thin films is a major achievement. XRD technique has been used for structural characterizations of NBT-BT films. Dielectric spectroscopy measurements were performed at room temperature in the frequency range 100 Hz-1 MHz. The best films show pure perovskite phase and good crystalline structure, as a function of specific deposition conditions. Unusual characteristics, especially dielectric constant values higher than those for bulk, have been found for films with specific crystallographic orientations.

  6. Induced piezoelectricity in isotropic biomaterial.

    PubMed

    Zimmerman, R L

    1976-12-01

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

  7. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2015-03-01

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

  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. Active vibration control of flexible cantilever plates using piezoelectric materials and artificial neural networks

    NASA Astrophysics Data System (ADS)

    Abdeljaber, Osama; Avci, Onur; Inman, Daniel J.

    2016-02-01

    The study presented in this paper introduces a new intelligent methodology to mitigate the vibration response of flexible cantilever plates. The use of the piezoelectric sensor/actuator pairs for active control of plates is discussed. An intelligent neural network based controller is designed to control the optimal voltage applied on the piezoelectric patches. The control technique utilizes a neurocontroller along with a Kalman Filter to compute the appropriate actuator command. The neurocontroller is trained based on an algorithm that incorporates a set of emulator neural networks which are also trained to predict the future response of the cantilever plate. Then, the neurocontroller is evaluated by comparing the uncontrolled and controlled responses under several types of dynamic excitations. It is observed that the neurocontroller reduced the vibration response of the flexible cantilever plate significantly; the results demonstrated the success and robustness of the neurocontroller independent of the type and distribution of the excitation force.