The Effects of B_2O_3 Addition and Sintering Temperature on the Electrical Properties of SnO_2 based Varistors

摘要

SnO_2 based varistor ceramics, as new type of varistor materials, have attracted increasing interest around the world. However, the effect of B_2O_3 addition on novel SnO_2 based varistors is still unclear. In this paper the effects of B_2O_3 addition on the electrical properties and sintering temperature of the SnO_2-Co_2O_3-Ta_2O_5 system were investigated. The experiments revealed that addition of trivalent boron can improve the densification of SnO_2 based ceramics. The samples doped with 0.025 mol% B_2O_3 had the highest sintering density. However between 0 mol% to 0.1 mol% B_2O_3 addition region there was little effect on non-linearity and breakdown field of SnO_2-Co_2O_3-Ta_2O_5 system. Obviously, the sintering temperature had a predominant influence on the SnO_2-Co_2O_3-Ta_2O_5 system; the samples sintered at 1400°C were superior to those sintered at 1350°C.