Effects of sub-grainboundaries on the characteristics of ZnO varistor ceramics

The effects of sintering temperature and soak time on the sub-grainboundaries in ZnO grains and the effects of the sub-grainboundaries on the electrical characteristics of ZnO varistor ceramics were investigated. It is found that the sub-grainboundaries tend to disappear with the increasing of the sintering temperature and soak time. The sub-grainboundaries can not only raise resistivity of ZnO grains, but also deteriorate the pulse energy absorption capability of ZnO varistor ceramics.