Effect of Sintering Temperature on the Microstructure and Electrical Properties of SnO2-Based Varistors

Abstract

SnO2-based varistors were successfully fabricated from the mixed powders, SnO2, Co2O3, Nb2O5 and Cr2O3. The effects of sintering temperature (1250, 1300, 1350 and 1400 °C) on the microstructure and electrical properties were investigated. The results reveal that the grain size increases with increasing the sintering temperature, and the breakdown electrical filed decreases gradually. When the sintering temperature was 1300 °C, the nonlinear coefficient of the as fabricated SnO2 based varistors presents the maximum of 27. Meanwhile, the leakage current possesses the minimum of 4.5 µA.