Affiliation:
1. School of Science, Hubei University of Technology, Wuhan 430068, China
2. Hubei Collaborative Innovation Center for Efficient Utilization of Solar Energy, Hubei University of Technology, Wuhan 430068, China
Abstract
Under the premise of using the solid-phase method to pre-sinter Bi2O3 and Sb2O3 into BiSbO4 as a substitute for equal amounts of Bi2O3 and Sb2O3 in the formula, the effects of co-doping with In(NO3)3, Al(NO3)3, and Y(NO3)3 on the microstructure and electrical properties of ZnO varistors were studied. The experimental results show that with an increase in In3+-doped molar concentration, the leakage current of the ZnO varistor shows a rapid decrease and then a slow increase trend. However, the nonlinear coefficient is the opposite of it. With the combined effect of the rare earth element Y3+, the average grain size is significantly reduced, which leads to an increase in the voltage gradient. At the same time, a certain amount of doped In3+ and Al3+ is dissolved into the grains, resulting in a decrease in grain resistance and thus a low level of residual voltage. The varistor with 0.6 mol% In3+, 0.1 mol% Al3+, and 0.9 mol% Y3+ doping ratios exhibits excellent overall performance. The nonlinear coefficient is 62.2, with the leakage current being 1.46 µA/cm2 and the voltage gradient being 558 V/mm, and the residual voltage ratio is 1.73. The prepared co-doped ZnO varistors will provide better protection for metal oxide surge arresters.
Funder
Hubei Key R&D Program Project