ZnO varistor ceramics prepared by the reduction–reoxidation method

• Published in: Journal of the European Ceramic Society 2015-10, Vol.35 (11), p.3025-3031
• Main Authors: Fu, Qiuyun, Chen, Tao, Ye, Xiaojian, Chen, Pengyuan, Liu, Yang, Gao, Chao, Hu, Yunxiang, Zheng, Zhiping, Zhou, Dongxiang
• Format: Article
• Language: English
• Subjects: BASE metal inner electrodes; Multilayer chip ZnO varistor; Reduction–reoxidation method
• ISSN: 0955-2219; 1873-619X
• DOI: 10.1016/j.jeurceramsoc.2015.04.002

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–reoxidation method. In this article, ZnO varistors were firstly prepared by the reduction–reoxidation method. Electrical performances of ZnO varistors sintered in air and nitrogen (N2 99.8%) were compared with those prepared by the reduction–reoxidation method. ZnO varistor ceramics sintered in N2 at 1000°C and then re-oxidized in air at 750°C for 2h exhibited excellent electrical properties such as a high nonlinear coefficient of 47.9 and a low leakage current of 0.06μA/cm2, which is promising for producing multilayer ZnO varistors with base metal electrodes.