Effect of ZnO Nano Powder on Electrical Properties of Varistors

Nano phase ceramics are interesting due to their extraordinary electrical, optical, mechanical, and chemical properties. These properties are more toughness, higher chemical reaction, and better sinterability. ZnO varistors are semi conductor ceramics, which their excellent nonlinear and electrical characteristic are induced from grain boundaries and are depended on microstructure. This is related to the size and morphology of ZnO grains. Based on a theoretical aspect, the finer primary particles with narrow size distributions, the better electrical properties. In this research, the effect of ZnO nano powder on electrical properties of ZnO varistors was investigated. The results showed that in the case of using ZnO nano powder, sintering time and temperature were decrease, Also, electrical properties such as nonlinear coefficient and were improved to 43 and 4200 v/cm versus 34.8 and 1420 v/cm respectively.