ZnO varistor ceramics prepared by the reduction-reoxidation method

摘要

Multilayer ceramic components with base metal inner electrodes should be sintered in a reducing or protective atmosphere to avoid oxidation of the base metal, and then re-oxidized in air or oxygen to control their electrical properties. It is called reduction remddation method. In this article, ZnO varistors were firstly prepared by the reduction reoxidation method. Electrical performances of ZnO varistors sintered in air and nitrogen (N-2 99.8%) were compared with those prepared by the reduction reoxidation method. ZnO varistor ceramics sintered in N-2 at 1000 degrees C and then re-oxidized in air at 750 degrees C for 2 h exhibited excellent electrical properties such as a high nonlinear coefficient of 47.9 and a low leakage current of 0.06 mu A/cm(2), which is promising for producing multilayer ZnO varistors with base metal electrodes. (C) 2015 Elsevier Ltd. All rights reserved.