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.