钛酸铋钠基无铅压电陶瓷的极化性能热稳定性研究进展

Research Progress on Thermal Stability of Polarization Performance in Bismuth Sodium Titanate-Based Lead-Free Ceramics

钛酸铋钠(Bi_(0.5)Na_(0.5)TiO_(3),简称BNT)陶瓷是一种A位复合钙钛矿无铅压电材料,其具有高居里温度、大电致应变、良好的弛豫特性和机电耦合性能等特点,特别是其机械品质因数随温度升高和振动速率的增加保持稳定,相对于商用的铅基压电陶瓷Pb(Zr,Ti)O_(3)(PZT)具有一定的优势,有望应用于致动器、滤波器、超声换能器等领域。但是,较低的退极化温度(T d)限制了BNT基材料的实际应用,因此,研究出具有高T d的无铅压电陶瓷具有重要意义。综述了BNT基陶瓷的退极化行为与改善极化性能热稳定性的3种方法:元素掺杂、第二相复合及淬火处理,介绍了这3种方法的最新研究进展,并对每一种方法的改性机理相关研究进行了阐述,提出了亟待解决的问题,为后续进一步提高BNT及其他无铅压电陶瓷的T d提供参考。

Bi_(0.5)Na_(0.5)TiO_(3)(BNT)is a lead-free piezoelectric material with A-site complex perovskite structure.It exhibits high Curie temperature,large electric field induced strain,special relaxor properties and large thickness mode electromechanical coupling factors.Specifically,it shows stable mechanical quality factor with the variance of temperature and vibration velocity in comparison with Pb(Zr,Ti)O_(3)(PZT).Thus,BNT based ceramics are expected to be applied in actuators,filters,ultrasonic transducers and other fields.However,they still have some problems,for example,low depolarization temperature(T d)making the operational temperature range of devices narrow,which limits the practical application of BNT-based materials.Therefore,the research of lead-free piezoelectric ceramics with high T d has great prospects in future.This article has reviewed depolarization behavior of BNT-based ceramic materials and three methods of increasing T d:elemental doping,composites with the second phase and quenching heat treatment,introduced the latest research progress of these methods and their mechanisms,and finally put forward several problems to be solved urgently.This review may provide a reference for further improvement of T d of BNT and other lead-free piezoelectric ceramics.