SrTiO3压敏电阻的化学蜕变

借电化学注氢的方法研究了 SrTiO_3 压敏电阻器在潮湿环境中的蜕变机理,即以 SrTiO_3 压敏电阻器的电极作为阴极在 0.01 mol/L NaOH 的溶液中进行水的电解。结果表明:该处理使其漏电流和介质损耗增加,非线性变差,丧失压敏特性。但通过一定的热处理之后,其压敏性能又可恢复。水电解产生的 H 原子向陶瓷颗粒边界扩散、化学吸附,破坏其绝缘阻挡层,造成失效。并对蜕变机理进行了探索。

Chemical Degradation of SrTiO3-based Varistor

Water-induced degradation in SrTiO3-based varistor was investigated through an electrochemical hydrogen charging method, in which the silver electrodes of the varistor were made as cathode in 0.01 mol/L NaOH solution to deposit hydrogen by electrolysis of water. Of the varistor, the dielectric loss and the leakage current were dramatically increased, and the nonlinearity obviously decreased after the treatment. It is proposed that adsorbed hydrogen atoms generated by electrolysis of water diffuse along grain boundaries and have reduction reactions with insulating potential barriers, resulting in observed degradation. The degraded properties can be recovered through an annealing in an oxidizing atmosphere. These results are meaningful for understanding and improving the reliability of SrTiO3-based varistor.