Influence of TiO2/Sb2O3 ratio on ZnO varistor ceramics

The influence of TiO2/Sb2O3 (Ti/Sb) ratio on the microstructure development and electrical properties of varistor ceramics in ZnO-(Bi2O3-TiO2-Sb2O3)-CoO-MnO2 system was investigated. Characterization of varistors was performed by XRD, SEM, d.c. degradation behavior, and electrical measurements. It is found that the Ti/Sb ratio greatly influences the microstructure and electrical properties of the ZnO varistor. The specimen with Ti/Sb ratio of 5 has the lowest breakdown field (20V/mm) and improved d.c. degradation behavior. (C) 2001 Elsevier Science Ltd. All rights reserved.