Hydrogen-induced degradation in SrTiO3-based ceramic varistors

For ZnO-based ceramic varistors, it was found that the current leakage is largely increased by the reduction of hydrogen generated in nickel electroplating and electroless nickel plating. Nickel acts as a barrier to protect the silver electrode of ZnO chip varistors from dissolution while soldering surface mounting. Hydrogen-induced degradation also occurs in in-service ZnO-based varistors when hydrogen is generated by the electrolysis of water condensed from environmental moisture. In this study, we investigated hydrogen-induced degradation in SrTiO3-based ceramic varistors, which shows that the ambient-temperature reduction of hydrogen is also an important cause for the degradation of SrTiO3-based ceramic varistors