108 / 2018-08-24 18:56:30

Effect of Sintering Temperature on Microstructure and Electrical Properties of ZnO-Based Varistor Ceramics Prepared from Nano-sized ZnO Powders

ZnO-based varistor,sintering temperature,high breakdown field,ceramics,nano-sized ZnO powders

The effect of sintering temperature on microstructural and electrical characteristics of ZnO-based varistors ceramics prepared from nano-size ZnO powders was investigated with XRD, SEM and I-V measurements, respectively. From the microstructure analysis, the grains gradually increased and the pores were eliminated with the increase of the sintering temperatures. Whereas the grain size distributions became more non-uniform. For a comprehensive evaluation of microstructure, samples sintered at 1050C have the best microstructure. As to the electrical properties, the samples sintered at 1050C showed superior performance, exhibiting a higher breakdown field E1mA of 805±10 V/mm, the largest nonlinear coefficient of 30±2.2 and the lowest leakage current IL of 1.38±0.29 μA. The improved electrical properties can be ascribed to the decreased ZnO grain size and enhanced microstructure homogeneity.