PZT压电陶瓷高温变形与失效的实验研究

Experimental Study of Temperature Dependent Deformation and Degradation Behaviour of PZT Piezoelectric Ceramics

随着工业设备集成化进程的加快,PZT压电陶瓷获得越来越广泛的应用,其工作环境也越来越复杂。例如,新一代节能环保型发动机中起致动作用的压电陶瓷叠层驱动器,工作时要承受力-热-电载荷的共同作用。因此,研究PZT压电陶瓷在高温下的变形与失效行为,对工业设计具有重要的指导意义。为此,本文利用自行搭建的压电陶瓷高温下电滞回线、蝶形回线和应力退极化曲线的测试装置,研究了PZT压电陶瓷在不同温度下的电致变形和应力退极化行为,得到了材料在不同温度下的电滞回线、蝶形回线、应力电位移曲线和应力应变曲线。实验结果表明,随着温度的升高,由电滞回线测得的剩余极化逐渐减小,蝶形回线逐渐变扁;由应力退极化产生的剩余极化和剩余应变也逐渐减小。极化量的改变是由材料的热释电效应(自发极化随温度的升高而减小)造成的,而应变量的变化是由晶胞畸变随着温度升高而减小所致。

PZT piezoelectric ceramics gets access to more wide application along with the integration process acceleration of industrial equipment,so its working enviroment has become more and more compliciated.For instance,the piezoelectric multilayer actuator used in a new generation of energy saving and environmental protection type engine will be subjected to combined thermo-electro-mechanical action.Therefore,understanding the deformation and failure behavior of PZT ceramcis at high temperature is important to industrial design.Two sets of self-designed and homemade testing device were used to measure the deformtion and polarization/depolarization of ferroelectric materials at high temperature and the ferroelectric hysterisis loops,the butterfly loops,the stress electric displacement curves and stress-strain curves of PZT ceramics were measured respectively within a temperature range from 25℃ upto 180℃.Experimental results show that along with the temperature increasing,the remanent polarization measured from ferroelectric hysteresis loops gradually decreases;the butterfly loops gradually becomes flat;the remanent polarization and residual strain gradually decreases due to the stress depolarization.The change of polarization amount is caused by pyroelectric effect of the material（Spontaneous polarization decreases with temperature increasing.）;whereas the change of strain amount is caused by lattice distortion which decreases along with temperature increasing.