Influence of Eu2O3 on microstructure and electrical properties of ZnO-Pr6O11 based varistors

ZnO-Pr6O11-based ZnO nonlinear ceramics are well studied for their stability. Improving the electrical properties and stability of varistors has been an important part of the research and development of ZnO ceramics. The doping of rare-earth oxides in previous studies did not result in better performance of ceramics. In this study, the doping of rare earth element europium oxide is carried out by the traditional solid phase sintering method using metal oxides ZnO-Pr6O11-CoO-La2O3 (ZPCL) as the substrate, and the microstructure and electrical properties of the samples are tested. It is found that the doping of Eu2O3 helps to increase the grain boundary barrier, effectively improves the nonlinear coefficient of varistors, which is a very important electrical parameter, and reduces the leakage current. The best performance of the varistors is obtained at 1.5 mol% Eu2O3 doping, with the nonlinear coefficient of 18.7, the leakage current of 0.04 mA/cm2, the highest barrier height phi b of 0.45 eV and the breakdown field of 1283 V/mm. This study provides a reasonable theoretical basis and experimental support for the improvement of the electrical properties of ZnO-Pr6O11-based ZnO ceramics, and lays a certain foundation for the doping of rare earth oxides in ceramics in the future.