Microstructure Design and Optimization of ZnO-Bi<sub>2</sub>O<sub>3</sub>-Sb<sub>2</sub>O<sub>3</sub> Based Ceramic Varistors

Abstract

ZnO-based varistor; Microstructure; design and optimization; Electrical properties Abstract. ZnO-based ceramic varistors of a commercially available ZnO-based varistor composition were prepared under sintering system of different temperatures and dwelling times. The microstructure and electrical properties were investigated systematically and optimized. With increasing sintering temperature from 1035 to 1175 °C and dwelling time from 1 to 4 h, the composition and microstructure phases of the samples almost had no change, but the samples prepared at 1035 and 1175 °C presented the highest porosity; the nonlinear coefficient generally increased, but the samples prepared at 1145 and 1175 °C almost presented the same value of nonlinear coefficient; the varistor voltage decreased; and the samples sintered at 1035 and 1175 °C presented the highest leakage current. From the microstructure and electrical performance, it was proposed that, for the given varistors, the optimum sintering system was 1145 °C for 2 h.