Influence of Bi3Zn2Sb3O14 pre-synthesis phase on electrical properties of the ZnO-Bi2O3 based varistor ceramics

The effects of the pre-synthesis phase Bi3Zn2Sb3O14 on microstructure and non-linear characteristic of ZnO varistor ceramics are investigated. The results are discussed and compared with previous studies of ZnO varistors with Sb2O3 additions. It is shown that adding Bi3Zn2Sb3O14 to ZnO varistor ceramics can effectively inhibit the growth of ZnO grains, which results in a smaller grain size and a significantly higher breakdown voltage comparing with Sb2O3 samples. On the other hand, Bi3Zn2Sb3O14 has a significant influence on the defect structure and component distribution of grain-boundary regions. When Bi3Zn2Sb3O14 content increases from 0 to 3 wt%, the value of the interface state density (N-s) increases sharply. At the same time, the electrical properties are improved gradually and reached an optimized value with the nonlinear coefficient (alpha) up to 43 corresponding to the high barrier height (phi(b)) of 2.04 eV. (c) 2020 Elsevier B.V. All rights reserved.