Fine-grained SnO_2 varistors prepared by microwave sintering for ultra-high voltage applications

摘要

In this research, fine-grained SnO2-based varistors with a simple microstructure and the mean grain size of 0.8 mu m were obtained by the microwave sintering method. The breakdown electric field measured for these varistors was 12 kV/cm that is 3 times higher than the conventional-sintered varistors. The high nonlinear coefficient (60) and low leakage current density (9 mu A/cm(2)) were achieved in fine-grained SnO2 varistors. The fine-grained SnO2 varistors appropriately clamped pulse current surges and the calculated value of the clamping voltage ratio of these varistors was 2. The excellent electrical properties and protective effect of fine-grained SnO2 varistors showed that these varistors are astonishingly suitable for ultra-high voltage applications. (C) 2018 Elsevier B.V. All rights reserved.