The Effects of B2O3 Addition and Sintering Temperature on the Electrical Properties of SnO2 Based Varistors

SnO2 based varistor ceramics, as new type of varistor materials, have attracted increasing interest around the world. However, the effect of B2O3 addition on novel SnO2 based varistors is still unclear. In this paper the effects of B2O3 addition on the electrical properties and sintering temperature of the SnO2-Co2O3-Ta2O5 system were investigated. The experiments revealed that addition of trivalent boron can improve the densification of SnO2 based ceramics. The samples doped with 0.025mol% B2O3 had the highest sintering density. However between 0mol% to 0.1mol% B2O3 addition region there was little effect on non-linearity and breakdown field of SnO2-Co2O3-Ta2O5 system. Obviously, the sintering temperature had a predominant influence on the SnO2-Co2O3-Ta2O5 system; the samples sintered at 1400℃ were superior to those sintered at 1350℃.