铌酸钾钠基无铅压电陶瓷的高压电活性研究进展

以Pb(Zr_(1–x)Ti)x)O)3(PZT)为代表的铅基压电陶瓷因为具有良好的压电性能和机电耦合性能已被广泛应用于科技、工业、军事以及日常生活中.但是, PZT基陶瓷中Pb的含量超过了60%(质量比),在生产、使用及废弃处理过程中都会给人类生态环境造成严重损害.因此,发展无铅压电陶瓷已成为世界压电陶瓷研究的热点之一.铌酸钾钠(K_(0.5)Na_(0.5))NbO_3 (KNN)无铅压电陶瓷因为具有较为优异的压电性能以及较高的居里温度,被认为是最可能取代铅基压电陶瓷的材料体系之一.经过研究者们的努力工作,改性后的KNN基无铅压电陶瓷压电性能已经接近或超过了某些铅基压电陶瓷的性能.本文综合介绍了具有高压电活性的KNN基无铅压电陶瓷国内外的研究进展,重点阐述了高性能铌酸钾钠基无铅压电陶瓷制备工艺及相关理论基础的研究进展,并就今后铌酸钾钠基无铅压电陶瓷研究发展的方向及前景提出建议.     

反铁电相变陶瓷低频发射换能器

在具有高阶形式的广义压电方程基础上,讨论掺镧改性锆锡钛酸铅PbLa(Zr,Sn,Ti)O3(PLZST)反铁电相变陶瓷的非线性机电耦合问题,得到类似传统线性压电方程的近似线性电致伸缩方程,给出了一种解决非线性反铁电相变陶瓷换能器电声转换问题的分析方法,即在直流偏置状态下对PLZST反铁电相变陶瓷的材料参数进行近似线性等效化处理进而分析换能器的电声转换问题.在此基础上,研制了水中谐振频率1.1 kHz新型反铁电相变陶瓷低频弯张换能器.湖上试验结果表明,与同结构同尺寸压电陶瓷弯张换能器相比,目前反铁电换能器样品的发射电压响应约高3dB,声源级高出9dB,并验证了本文所提出的分析非线性反铁电相变陶瓷换能器方法的正确性.     

基于相变换能机理的反铁电陶瓷水声换能器初探

阐述了改性锆锡钛酸铅Pb(Zr,Sn,Ti)O3(PZST)反铁电陶瓷作为一种基于相变换能机理的大应变电致伸缩材料的性能特征以及作为水声换能器新型有源材料的优势。采用掺镧改性锆锡钛酸铅PbLa(Zr,Sn,Ti)O3(PLZST)反铁电陶瓷材料首次设计制作了纵振式反铁电陶瓷水声换能器。试验结果表明,PLZST反铁电陶瓷用于水声换能器研制在技术上是可行的,与压电陶瓷换能器比较,目前反铁电换能器样品的等效发射电压灵敏度提高3~5dB以上。根据实验情况,认为在发射电压灵敏度和声源级方面具有进一步提升的潜力。     

高频宽带嵌套式复合材料换能器*

研制了一种嵌套式高频宽带复合材料换能器,利用1-3型压电复合材料Q值较低、频带较宽的特点,采用组合式的结构拓展换能器的工作带宽。通过切割框型压电陶瓷、灌注环氧树脂得到压电复合材料框型敏感元件,再将不同厚度的框型敏感元件沿轴向嵌套从而制成多层嵌套的压电复合材料敏感元件。建立1-3型压电复合材料中压电小柱的等效电路,根据等效电路计算出压电小柱的谐振频率,并与1-3型压电复合材料的谐振频率理论计算结果进行对比。通过ANSYS软件对敏感元件结构进行仿真,并根据仿真结果确定了敏感元件的最佳设计方案。最终制作出的换能器进行水下测试,该换能器的谐振频率为310kHz,最大发送电压响应为188.5dB,-3dB带宽可达130kHz,接收灵敏度最大可达-186.8dB,-3dB带宽可达90kHz,谐振频率处-3dB的指向性开角约为2.4°。该嵌套式敏感元件可实现换能器宽带发射与接收声波的目标。     

长轴加长型宽带弯张换能器

Ⅳ型弯张换能器的机械品质因数较高,带宽不宽.为改善其带宽性能,在椭圆管形弯张壳体的基础上,利用多模态耦合的原理,提出了一种长轴加长型弯张换能器.以新型弛豫铁电单晶铌镁酸铅—钛酸铅(PMNT)为驱动材料,利用有限元软件ANSYS对弯张换能器进行了设计分析并制作了换能器样机.测量得到在1.6～16 kHz的频率范围内,换能器的最大发送电压响应136 dB,响应起伏7.8 dB.理论分析与实验结果表明,与Ⅳ型弯张换能器相比,长轴加长型弯张换能器在保持频率低,响应高等优点的同时,显著拓宽了弯张换能器的带宽.     

弛豫铁电单晶/压电陶瓷混合激励换能器EI北大核心CSCD

为了降低纵向换能器尺寸并提高发射带宽和发送电压响应,研究了一种弛豫铁电单晶/压电陶瓷混合激励换能器,换能器由[011]方向极化PIN-PMN-PT单晶和PZT-4压电陶瓷混合激励,利用多模态振动耦合的原理,通过单晶的32模式振动,可以灵活调整两种振子之间的驱动能力和刚度分配。首先通过四端网络法得到了换能器等效电路并计算了其谐振频率,然后利用有限元方法对换能器进行了仿真优化,最后制作了试验样机并进行了测试分析。换能器样机外径86 mm、长度80 mm,工作频带13~38 kHz,最大发送电压响应为144.9 dB,带内发送电压响应起伏小于6 dB,具有良好的宽带、小尺寸工作性能。     

磁致伸缩-压电联合激励凹筒型发射换能器

设计制作了一种新型磁致伸缩-压电联合激励凹筒型发射换能器,采用稀土超磁致伸缩材料Terfenol-D与PZT压电陶瓷作为联合激励元件,模拟计算与实测结果均表明,与采用单一振子激励的凹筒型发射换能器相比,此种新型换能器在保持尺寸小、频率低等优点的同时,显著拓宽了工作频带并提高了辐射声功率.换能器外型尺寸为φ88 mm×316 mm,水中谐振频率1.30 kHz,-3 dB带通Q值1.43,谐振频率下发射电压响应级135.1 dB.     

混合激励纵振换能器的研究

纵振式换能器是水声领域中不可或缺的一类中频段换能器,本文以超磁致伸缩材料Terfenol-D和压电陶瓷材料PZT作为驱动元件设计混合激励纵振式换能器。利用ANSYS有限元软件建立了有限元模型,对换能器的电声参数进行了优化,并制作一宽带混合激励纵振式换能器,实验测得的换能器与仿真的结果较为吻合,实测换能器的最大发送电压响应为145dB,其工作频带为4kHz-16kHz,频带内发送电压响应起伏为±4.5dB。     

红外探测用无铅铁电陶瓷的热释电特性研究进展

铁电陶瓷具有优异的热释电性能,是红外探测器的核心敏感元材料,目前普遍采用铅基陶瓷材料,发展无铅铁电陶瓷用于热释电红外探测是近年来电介质物理与材料的一个热点.本文综述了无铅铁电陶瓷的热释电性能研究进展,主要包括钛酸钡基、钛酸铋钠基、铌酸锶钡基、铌酸钾钠基等系列铁电陶瓷的热释电效应研究现状,归纳了不同体系增强热释电效应的手段.通过比较分析主要无铅铁电陶瓷的热释电性能和退极化性能的制约关系,指出钛酸铋钠基陶瓷是目前最具应用潜力的无铅材料体系,并对无铅铁电陶瓷热释电探测应用未来的发展方向进行了展望.     

磁致伸缩-压电联合激励凹简型发射换能器

设计制作了一种新型磁致伸缩-压电联合激励凹简型发射换能器,采用稀土超磁致伸缩材料Terfenol-D与PZT压电陶瓷作为联合激励元件,模拟计算与实测结果均表明,与采用单一振子激励的凹筒型发射换能器相比,此种新型换能器在保持尺寸小、频率低等优点的同时,显著拓宽了工作频带并提高了辐射声功率。换能器外型尺寸为φ88 mm×316 mm,水中谐振频率1．30 kHz,-3 dB带通Q值1．43,谐振频率下发射电压响应级135．1 dB。     

A hybrid magnetostrictive-piezoelectric barrel-stave projector

A hybrid magnetostrictive-piezoelectric barrel-stave projector is designed and developed. The new type transducer is driven by the union of rare-earth giant magnetostrictive material Terfenol-D and PZT piezoelectric ceramic. Combining the advantages of low frequency performance within a compact size, it proves that the hybrid projector has a much broader band and higher sound power than that with single magnetostrictive or piezoelectric driver by the simulated and measured results. The prototype of the hybrid projector has a size of 88 mm in outside diameter and 316 mm in length, with an underwater resonant frequency of 1.30 kHz, Q factor of 1.43 for -3 dB bandwidth, and transmitting voltage response level of 135.1 dB at the resonant frequency.     

折回型纵向振子低频拼合圆柱换能器

提出一种具有小尺寸、低频、水平无指向性的新结构换能器——折回型纵向振子拼合圆柱换能器,换能器由4组共享尾质量块的折回型压电纵向振子正交布置驱动环形辐射面拼合构成。采用有限元方法对换能器进行优化设计,并制作了换能器样品。实验结果表明:换能器直径为Φ180 mm,谐振频率为1.5 kHz,最大发射电压响应为131 dB,最大声源级不低于188 dB,水平全向。该换能器具有低频、小尺寸、水平无指向性的特点,具有良好的应用前景。      

多谐振宽带Janus-Ring换能器

提出了一种多谐振宽带Janus-Ring换能器,两个一定距离的压电圆环换能器(Ring换能器)嵌套在双面纵振Janus换能器的两端,Ring换能器的径向振动、Janus换能器的纵振动与它们中间形成的Helmholtz液腔振动相耦合,可大大拓展换能器的工作带宽。使用有限元方法设计并研制了Janus-Ring换能器样机,经测试在1.8~8.0 kHz范围内,样机最大发射电压响应144 dB,起伏小于6 dB。相比传统的Janus-Helmholtz换能器,Janus-Ring换能器有效拓展了工作频带,增大了发射电压响应,减小了频带内的发射电压响应起伏。      

Broadband flextensional transducer with major axis lengthened

The bandwidth of the Class IV flextensional transducer is narrow for its high mechanical quality factor.For improving its bandwidth performance,a flextensional transducer with major axis lengthened was proposed by the theory of multiple-mode-coupling based on the oval shell.The transducer driven by novel relaxor ferroelectric single crystal lead magnesium niobate-lead titanate(PMNT)was designed and analysed using finite element software ANSYS and a prototype of the transducer was developed.The transmitting voltage response of the transducer reaches to 136 dB with fluctuation 7.8 dB from 1.6 kHz to 16 kHz.Based on the theoretical analysis and experimental results,it proves that the flextensional transducer with major axis lengthened has a much broader bandwidth than the ClassⅣflextensional transducer combing with the advantages of low frequency and high response.     

Performance of a low-frequency,multi-resonant broadband Tonpilz transducer

The underwater performance of a high-power multi-resonant Tonpilz transducer with a nearly flat frequency response and a power handling capability of 2 kW (peak) is reported here. A maximum transmitting voltage response (TVR) value of 156 dB re: 1 microPa/V at 1 m has been achieved at 3 kHz with a specially designed matching coil. A maximum receiving sensitivity (RS) of -164 dB re: 1 V/microPa at 3 kHz has been measured without using a matching coil. The horizontal half-power beam width of the transducer at 4 kHz is 101 degrees with a directivity index of 4 dB. This transmitter can be used for oceanographic applications such as subbottom profiling as well as long-range underwater communication.     

Study of 1-3-2 type piezoelectric composite transducer array

Based on a new structure of precise location and decoupling between the transducer elements, high frequency underwater transmission transducer arrays with 4 elements and 8 elements serried uniform linear array were studied, using novel 1-3-2 type piezoelectric composite as the sensing material. There are ceramic framework supports in the transverse and longitudinal directions in 1-3-2 type piezoelectric composite structure; the transducer is free from the influence of outside mechanical impact and the environment temperature change. Transducer and array samples have been designed, fabricated and measured. The resonant frequency is 150 kHz, resonant transmission response greater than 160 dB, and bandwidth is from 140 kHz to 160 kHz. The results indicate that, the transducer array has wide bandwidth, high sensitivity, stabile performance, and good coherence.     

具有大指向性开角及高发射电压响应的发射换能器

应用复合变幅杆及夹心式换能器结构,研制了一种指向性开角较大且发射电压响应较高的发射换能器。应用有限元方法对换能器的工作频率,发射电压响应及指向性进行了理论计算。并与实验结果进行了比较,结果较吻合。本文研制的换能器工作频率为75.6kHz,发射电压响应级达到1 56dB(基准值1V/μPa),-3dB发射指向性开角100°     

Antiferroelectric phase transitions ceramics low frequency projector

In order to discuss the nonlinear electromechanical properties of the La-modified lead zirconate titanate stannate antiferroelectric ceramics PbLa（Zr,Sn,Ti）O₃（PLZST）,the approximate linearized electrostrictive equations exactly the same form as the classical linear piezoelectric equations were derived from the second-order terms of the generalized piezoelectric equations.An analytic approach of solving the electroacoustic transduction problems of the nonlinear antiferroelectric phase transitions ceramics transducers was presented.The nonlinear properties of the PLZST can be linearly equivalent with a maintained bias based on the approximate linearized electrostrictive equations for analyzing the electroacoustic transduction problems of the transducers.An innovative antiferroelectric ceramics low frequency classⅣflextensional transducer with resonance frequency 1.1 kHz based on the approach was developed which utilizes the PLZST as active elements.The lake authentications indicated that the use of PLZST for transducers yielded presently a 3 dB increase in TVR and a 9 dB increase in SL over its PZT-4 counterpart,and the approach was valid.