交直流老化后ZnO压敏电阻宏观电容量随时间变化的特性分析

Analysis on the Time-Dependent Characteristics of ZnO Varistor's Capacitance after DC and AC Degradation

针对ZnO压敏电阻在交、直流老化作用后,其宏观电容量随时间变化特性的问题,基于砖块模型(block model)对影响ZnO压敏电阻宏观电容量的相关参数进行了理论分析,通过对ZnO压敏电阻样品分别施加不同时长的交流以及直流老化试验时,发现ZnO压敏电阻的宏观电容量在接受交、直流老化后随着时间的延长呈现先降低后增长的趋势;当交、直流老化时间较短时,宏观电容量相较初始值存在小幅降低,而当交、直流老化时间较长时,宏观电容量相较初始值存在大幅的增长,得出宏观电容量随时间的变化是由界面态俘获电子的释放过程以及晶界层热破坏过程共同作用所导致的结论,这对研究ZnO压敏电阻的老化特性具有一定的参考价值。

In order to study the time-dependent characteristics of ZnO varistor＇ s microscopic capacitance after AC and DC degradation, a theoretical analysis is made on the parameters which influence the microscopic capacitance of ZnO varistor based on the block model. By applying the AC and DC degradation test on the samples of ZnO varistors with different experimental time, it is found that the macroscopic capacitance tends to decrease firstly and then increase after AC and DC degradation. When the AC and DC degradation time is relatively short, the microscopic capacitance reduces a little compared to the initial value. When the AC and DC degradation time is long enough, the microscopic capacitance substantially increases eompared to the initial value. Based on the investigating results, it can be concluded that the time-dependent characteristics of microscopic capacitance are resulted from the releasing process of electron captured by interface state and the thermal failure process of grain boundary layer, which has a certain reference value for studying the degradation properties of ZnO varistor.