湿度对PZT铁电陶瓷压痕裂纹滞后扩展的影响

Effect of Relative Humidity on Indentation Crack for PZT Ferroelectric Ceramics

在不同湿度(2%、30%、98%)的空气中,研究了极化的锆钛酸铅(PZT-5)铁电陶瓷压痕裂纹在残余应力、电场作用下的滞后扩展。结果表明,当RH≤30%时残余应力不能引起PZT铁电陶瓷卸载压痕裂纹的滞后扩展,当RH=98%时,残余应力和介质的耦合作用能使压痕裂纹在经过1个孕育期后发生滞后扩展。在不同湿度(2%、30%、98%)的空气中沿试样极化方向加相同的外电场(E=1.5 kV/cm),压痕裂纹均发生滞后扩展,并且裂纹扩展量随空气湿度的增加而增大。

The propagation process of indentation crack in air of different relative humidity （2%, 30%, 98% ） for a poled PZT- 5 ferroelectric ceramic was investigated. Results showed that the residual stress itself was not enough to induce delayed propagation of the crack when the relative humidity was small （RH≤30%）. However, it could cause delayed propagation of the crack when the relative humidity was higher, such as 98%. When an applied electric field that parallel to the direction of polarization was 1.5 kV/cm, the indentation crack in air of different relative humidity propagated. The propagation length of cracks increased with increasing relative humidity.