Bi0.5(Na0.82-xK0.18Lix)0.5TiO3无铅压电陶瓷的微结构与电性能

采用传统陶瓷制备工艺制备了[Bi0.5(Na0.82-xK0.18Lix)0.5]TiO3(x=0.01~0.07)无铅压电陶瓷.研究了该体系陶瓷的微结构以及应力对平面机电耦合系数kp和压电常数d33的影响.结果表明,[Bi0.5(Na0.82-xK0.18Lix)0.5]TiO3无铅压电陶瓷具有单一钙钛矿结构,Li+有抑制晶粒长大的作用.当x=0.03时,压电陶瓷样品表现出优良的压电性能:压电常数d33和平面机电耦合系数kp分别为154 pC/N和0.296.同时发现,退火可消除内应力,有利于提高d33,但会使kp减小;极化会引起介电常数εr减小,电畴转向过程中产生的应力对d33影响较为明显     

压电陶瓷极化优化算法与装置

根据压电陶瓷参数优化算法,设计了一种新型压电陶瓷极化优化装置。通过单片机检测极化过程电流变化,自动调节极化过程,实现了压电陶瓷参数一致性的控制。该装置具有性能参数控制好、操作方便、安全等特点,压电陶瓷参数一致性的成品率高。     

一种由压电双晶片测量压电材料参数的动态方法

本文根据悬臂梁式压电双晶片的动态导纳矩阵 ,提出一种压电材料参数动态测试模型 ,用于测量压电双晶片的几个主要材料参数 :压电应变常数d31、机电耦合系数k31、介电常数εT33、弹性柔顺系数SE11及材料参数的温度特性。本文的这种测量方法不同于通常的由标准试样测量压电材料参数的方法 ,是直接由一种实用元件—压电双晶片 (非标准试样 )测量压电材料的参数。文中详细描述了测试原理、测试步骤及一种实际试样的测试结果。理论与实验结果表明 :这种新的测试方法是可行的。     

压电陶瓷风力发电机的创新设计

通过对压电发电模型的分析,总结出了各参数对压电陶瓷开路电能及破坏力的影响。在此基础上运用Solidworks软件设计出了创新型的悬臂梁式压电陶瓷风力发电机,该装置能实现能量的自供给,可以解决那些不能提供电源、不易更换电池地区微型器件的供电问题。     

面向电力设备检测与诊断的压电材料及器件

随着中国智能电网建设不断推进及电网规模的扩大,以压电材料为核心的传感器和能量采集器在电力系统在线监测、故障检修、无线传感器网络等方面扮演着越来越重要的角色。从电力检测和传感器自取能出发,回顾近年来基于压电效应的电压电场传感器、声检测和环境能量采集装置的研究进展并介绍了压电陶瓷、压电驻极体、压电复合材料等传统和新兴的压电材料。在现有研究基础上,指出在智能电力系统建设中各类压电器件所面临的挑战,包括频率匹配、环境适应性和集成化等,需要新的微纳加工技术、探索压电效应与其他物理效应耦合、设计新型压电材料和能量收集电路来助力新型压电器件的实际应用。     

基于频率特性的Rosen压电变压器参数的仿真测量和分析

Rosen型压电变压器在便携式高压应用方面有其独特的优点.压电变压器的模型参数是仿真分析压电变压器电气特性的重要参数.通常,这些模型参数的获得需要借助价格昂贵的阻抗分析仪.论文基于实测压电变压器电压增益-频率响应特性,提出了一种实用的压电变压器模型参数的求解方法.首先通过实验测量压电变压器的电压增益-频率响应特性,并将...     

压电叠堆联接方式及低频发电特点的研究

压电发电是一种新型的振动能量收集技术。论文推导并给出了压电叠堆在33模式低频振动时输出电压和功率的数学表达式,并分析指出了输出电压和功率与压电系数、压电片个数、压电片厚度、激振力、激振频率正相关,与电极面积和介电常数负相关;电学串联的压电叠堆可以输出较高的开路电压;电学并联的压电叠堆可以输出较高的输出电流和功率。文中设计了压电叠堆夹持装置和振动发电实验装置,在振动频率5Hz、激振力26N的情况下得到两片电学串联叠堆和并联叠堆的最大功率分别为0.14μW和0.4μW;实测输出电压随振动频率、电阻、压电片个数、振子厚度和电极面积的变化趋势与理论预测相符。     

压电陶瓷式电子电压互感器的信号处理方法

为了提高压电陶瓷式电子电压互感器的静态和暂态稳定性,针对其非接触测量方式的特点,提出一种基于恒光强控制电路的光/电转换方案并开发了与之对应的动态误差补偿系统,编写了数字化程序,解析了信号处理过程中的相关问题,最终提供数字量和模拟量两类输出信号.利用该方法对10 kV压电陶瓷式电压互感器样机进行数据采集,数据表明,该信号处理装置性能稳定,能有效提高压电陶瓷式电压互感器的动态稳定性,从而提高电压互感器的精确度.     

悬臂梁式压电振动能量俘获装置输出功率分析与建模

文章通过理论分析,从悬臂梁式压电振动能量俘获装置常见结构的等效电路出发,结合俘能装置的结构参数以及电气参数等特性,总结推导出了该装置输出电压的近似公式,以及低阻值负载情况下恒流源的等效输出模型,也由此推出了多装置并联拓扑结构的输出电压公式。并基于该理论分析,利用Matlab对悬臂梁式压电振动能量俘获装置进行仿真,仿真结果验证了这些近似公式的正确性。     

AF9M1对KNN基陶瓷的结构与压电性能的影响

采用传统固相烧结法制备了K0.5Na0.5Nb O3-x Al(Fe0.9Mn0.1)O3(KNN-AF9M1)无铅压电陶瓷,着重研究了AF9M1的不同掺杂量(x分别为0,0.02,0.04,0.06,0.08)对陶瓷显微结构和压电性能的影响。结果表明,室温下,少量AF9M1的掺杂并未改变KNN基陶瓷正交相钙钛矿结构,但有助于陶瓷晶粒的生长及致密化。随着AF9M1含量的增加,陶瓷的压电常数(d33)、机电耦合系数(kp)、机械品质因数(Qm)和居里点(Tc)均先增大后减小,当x=0.04时,均达到最大值,分别为121 p C/N、0.35、179和392℃。     

Fabrication and characterization of flexible piezoelectric composites with natural rubber matrix

Abstract

This work aims to fabricate and characterize flexible piezoelectric composites with natural rubber (NR) matrix. Different amounts of Pb(Mg_1/3Nb_2/3)_0.65Ti_0.35O₃ (PMNT) powders were added in NR matrices. Porosity, tensile strength and percent elongation at break of composites tended to decrease with increasing PMNT content. The dielectric constant of the NR materials was found to be 3.5. It was raised up to 4.2, 5.0, 4.5, 4.8 and 5.1 when 60, 80, 100, 120 and 150 phr PMNT powders were added. However, dielectric loss of NR materials did not change with PMNT additions. Among this composite system, the NR/100PMNT composite showed the best piezoelectric properties, which its output voltage, piezoelectric coefficient (d₃₃) and piezoelectric voltage coefficient (g₃₃) values were equal to 1.61 V, 2.1?×?10^?4 pC/N and 5.4?×?10^?6 V?m/N, respectively. This composition composite is a promising material suitable for further improvement to be used as piezoelectric generators in energy harvesting applications.     

Improved Electromechanical Response in Rhombohedral BaTiO3

Zr-, Hf-, and KNb-doped BaTiO₃ materials were prepared in a composition range that stabilizes the rhombohedral phase above room temperature. These materials were prepared as bulk polycrystalline material using standard solid-state reaction methods. X-ray diffraction was used to confirm the existence of a stable rhombohedral phase while dielectric constant measurements confirmed the expected phase transition temperatures. A piezoelectric coefficient of d₃₃ = 290–470 pC/N was obtained for Zr- and Hf-doped BaTiO₃, compared with d₃₃ = 75 pC/N for pure BaTiO₃. An electrostrictive coefficient of Q₃₃ = 0.37 m⁴/C² was obtained for the KNb-doped material, compared with Q₃₃ = 0.11 m⁴/C² for pure BaTiO₃. The maximum strain measured for the doped samples was 5–10 times higher than that of pure BaTiO₃.     

Piezoelectric Energy Harvesting under High Pre-Stressed Cyclic Vibrations

Cymbal transducers have been found as a promising structure for piezoelectric energy harvesting under high force (∼ 100 N) at cyclic conditions (∼ 100–200 Hz). The thicker steel cap enhances the endurance of the ceramic to sustain higher ac loads along with stress amplification. This study reports the performance of the cymbal transducer under ac force of 70 N with a pre-stress load of 67 N at 100 Hz frequency. At this frequency and force level, 52 mW power was generated from a cymbal measured across a 400 kΩ resistor. The ceramic diameter was fixed at 29 mm and various thicknesses were experimented to optimize the performance. The results showed that the PZT ceramic of 1 mm thickness provided the highest power output with 0.4 mm endcap. In order to accommodate such high dynamic pressure the transducer and cap materials were modified and it was found that the higher piezoelectric voltage constant ceramic provided the higher output power. Electrical output power as a function of applied ac stress magnitude was also computed using FEM analysis and the results were found to be functionally coherent with experiment. This study clearly demonstrated the feasibility of using piezoelectric transducers for harvesting energy from high magnitude vibration sources such as automobile.     

基于压电晶体的微质量检测系统研究进展

压电晶体传感器利用压电石英晶体振荡频率对晶体表面质量负载和表面性状的高度敏感性,来实现对物质微质量的检测。介绍了压电晶体传感器的原理,给出了检测系统的硬件组成及数据处理与分析软件设计,分析了其应用现状,并对该检测系统的发展趋势进行了展望。     

Thickness Dependence of Piezoelectric Properties for PZT Thin Films with Regard to MEMS Applications

In this work we report on the investigation of the piezoelectric and ferroelectric properties of Pb(Zr,Ti)O₃ (PZT) thin films with a composition of 45% zirconium and 55% titanium prepared by chemical solution deposition (CSD) regarding the major properties required in MEMS applications. Therefore we have measured the polarization and the piezoelectric coefficient d ₃₃ and strain using a high-resolution double beam laser interferometer. We found that d ₃₃ alike the strain is nearly independent of the sample thickness. To estimate the lifetime of MEMS we stressed the samples by applying switching and non-switching voltage pulses. In the non-switching case, no change of the material properties was observed whereas the use of switching voltage pulses resulted in a strong decrease of the piezoelectric properties and the polarization. Here we found a linear behavior between the material properties in the fatigued state and the sample thickness.     

Design and Performance of Miniaturized Piezoelectric Step-Down Transformer

Piezoelectric transformers are expected to be small, thin and highly efficient, and which are attractive as a transformer with high power density for step down voltage. For these reasons, we have attempted to develop a step-down piezoelectric transformer for the miniaturized adaptor. we propose a piezoelectric transformer, operating in thickness extensional vibration mode for step-down voltage. This transformer consists of a multi-layered construction in the thickness direction. In order to develop the step-down piezoelectric transformers of 10 W class and turn ratio of 0.1 with high efficiency and miniaturization, the piezoelectric ceramics and piezoelectric transformer designs are estimated with a variety of characteristics. The basic composition of piezoelectric ceramics consists of ternary yPb(Zr_xTi_{1 – x})O₃–(1–y)Pb(Mn_1/3Nb_1/3Sb_1/3)O₃. In the piezoelectric characteristics evaluations, at y = 0.95 and x = 0.505, the electromechanical coupling factor(k_p) is 58%, piezoelectric strain constant (d₃₃) is 270 pC/N, mechanical quality factor(Q_m) is 1520, permittivity ( ₃₃^T/₀) is 1500, and Curie temperature is 350C. At y = 0.90 and x = 0.500, k_p is 56%, d₃₃ is 250 pC/N, Q_m is 1820, ₃₃^T/₀ is 1120, and Curie temperature is 290C. It shows the excellent properties at morphotropic phase boundary regions. PZT-PMNS ceramic may be available for high power piezoelectric devices such as piezoelectric transformers. The design of step-down piezoelectric transformers for adaptor proposes a multi-layer structure to overcome some structural defects of conventional piezoelectric transformers. In order to design piezoelectric transformers and analyze their performances, the finite element analysis and equivalent circuit analysis method are applied. The maximum peak of gain G as a first mode for thickness extensional vibration occurs near 0.85 MHz at load resistance of 10 . The peak of second mode at 1.7 MHz is 0.12 and the efficiency is 92%.     

Piezoelectric materials for bistable energy harvester: A comparative study

This paper deals with the potential of various lead-free piezoelectric materials for energy harvesting. The performance of these materials is simulated for unimorph bistable piezoelectric energy harvester. The finite element method considering first-order shear deformation theory is used to model the system. The energy harvesting potential of bistable system (Non-linear) is compared with its linear counterpart. The results depict that the mean power density is almost 100% higher in case of bistable system. K_0.5Na_0.5NbO₃-LiSbO₃ (KNN-LS) family exhibited better performance than the conventional lead-based piezoelectric material lead zirconate titanate (PZT). The mean power density of K_0.5Na_0.5NbO₃-LiSbO₃-CaTiO₃ (2 wt.%) is reported to be 65% higher than PZT.