基体电导率对0-3型铁电复合材料高压极化行为及损耗的影响

The influence of the matrix electrical conductivity on the dc poling behaviors and the loss of 0-3 ferroelectric composites

提出了一个0-3型聚合物基铁电复合材料的直流高压极化模型.模型中考虑了聚合物/铁电陶瓷界面处自由电荷的积聚及极化初始时刻的真实情况,利用拉普拉斯静电场方程,并结合边界条件,得到了直流高压极化过程中复合材料的极化强度、界面电流密度等随时间的演化方程,同时得到介电常数、介质损耗等物理特性的表达式.此外,实验制备了分别以环氧树脂E-44和铁电共聚物P(VDF-TrFE)为基体的两种0-3型铁电复合材料.从理论和实验两方面研究了基体电导率对极化行为以及介质损耗的影响.两方面结果均表明:随基体电导率增加,极化时间缩短,陶瓷相的极化强度及复合材料的整体电性能提高,但是漏电流及介质损耗增加.而且实验结果与直流高压极化模型的预测结果符合.

A dc poling model is developed for the 0-3 ferroelectric composite by employing Laplace equation, combined with certain boundary conditions and taken account of the initial conditions of the polymer/ferroelectric ceramic interfacial charges . Two kinds of 0-3 composites with different matrixes, namely the PZT/epoxy and PZT/P（VDF-TrFE） composites, were prepared. The influences of matrix electrical conductivity on the poling behaviors were studied experimentally and theoretically. The results showed that the experimental dates are fitted well with the theoretical results：with increased electric conductivity of the matrix, the poling time is shortened, and the polarization of ferroelectric ceramic and the total electric properties of composites are improved.Howerer,the leakage current and dielectric loss are increased,too.