Influence of Sintering Temperature on the Microstructure and Properties of ZnO Varistor Ceramics Prepared by Chemical Precipitation Method

Abstract

With the development of ZnO arresters towards high voltage gradient and miniaturization, more stringent requirements are put forward for ZnO varistor ceramics, and higher requirements are also placed on the uniformity of the distribution of added components in ZnO varistor ceramic powders. this paper, ZnO varistor powders were prepared by the chemical precipitation method, and ZnO varistor ceramics were prepared at different sintering The properties of the samples were analyzed by various characterization methods, and their microstructure and electrical properties were studied. The experimental findings indicate that the mean grain size of ZnO varistor ceramics become larger as the sintering temperature increases, and the grain boundary nonlinearity coefficient and potential barrier height first increase and then decrease. When the sintering temperature is 1050°C, the grain size of the ZnO varistor ceramic sample is better, the grain boundary barrier height is the highest, and the comprehensive electrical properties are better. Compared with the common 1100°C$\sim$1200°C in the literature, it not only reduces the energy consumption but also improves the performance of ZnO varistor ceramics. It is speculated that the uniform distribution of doping ions before sintering reduces the sintering temperature. The lower temperature reduces the volatilization of oxide additives such as bismuth oxide and avoids abnormal grain growth.