ZnO压敏电阻直流老化特性的研究

DC Aging Characteristics of ZnO Varistors

ZnO压敏电阻是电子和信息化领域重要的过电压防护器件,对电子与通信系统的运行安全有着至关重要的作用。本研究基于压敏电阻直流老化特性实验平台,开展了热电应力下ZnO压敏电阻温度特性、荷电率特性以及长期直流电压下老化特性的变化规律研究。实验与分析结果证明:1)在电应力与热应力作用下,ZnO压敏电阻的泄漏电流和功率损耗随着荷电率增大而增大;2)同一型号压敏电阻在同温度(115℃),不同荷电率下两组直流老化实验,泄漏电流曲线经历了快速上升、缓慢下降至平稳、激增3个变化阶段,两组老化时间存在较大差异;3)压敏电阻长时间直流老化实验中,10 K 250压敏电阻片在97%荷电率和145℃温度条件下,历经264 h的老化过程,其压敏电阻泄漏电流、功率损耗的急剧增长,压敏电压、非线性系数、漏电流发生显著的变化。因此,传统意义上将压敏电压值降为初始值的10%作为老化实验寿命终结判据对于直流老化来说需要进一步研究。

ZnO varistor is an important overvoltage protection device in the field of electronics and information technology,which plays a vital role in the safe operation of electronic and communication systems.Based on the experimental platform for DC aging characteristics of varistor,the temperature characteristics,charge rate characteristics and aging characteristics of ZnO varistor under thermoelectric stress are studied.The experimental and analytical results show that:1)Under the action of electrical stress and thermal stress,the leakage current and power loss of ZnO varistor increase with the increase of the charge rate.2)The same type of varistor is at the same temperature(115℃).The two groups of DC aging experiments under different charge rates have experienced rapid rise and slow decline to three stages of steady and rapid increase.There are large differences in aging time between the two groups.3)Long-term DC aging test of varistor:in the case of the aging process of 264 hours under the condition of 97%charge rate and 145℃,the varistor leakage current and power loss increase sharply,Significant changes have taken place on varistor voltage,nonlinear coefficient and leakage current.Therefore,reducing the varistor voltage to 10%of the initial value is traditionally regarded as the criterion of the end of aging test,which need further research for DC aging.