Effect of Nonuniformities of Microstructure and Electrical Property of Grain Boundary to the Global Electrical Characteristics

The influence of the geometry and topology of the granular microstructure, as well as the properties and the distribution of the different types of microjunctions on the features of bulk varistor devices is an important and interesting problem. Simulating analysis on the actual microstructure and electrical characteristics of ZnO varistors is used to effectively analyze the influences of different factors, such as grain size, barrier voltage and nonlinearity coefficient of single grain boundary, on the global electrical characteristics, and the effect of their distribution related to the nonuniformities of ZnO varistors was considered. The current concentration and dumb grains lead to the nonuniform of current distribution, and the energy handling capability of ZnO varistor is reduced