Electrical characteristics of SnO2 voltage-sensitive ceramics doped with Ni2O3

SnO2 voltage-sensitive ceramics is a kind of ceramic with nonlinear characteristics, which is the most promising new material for high voltage and large current varistors. At present, the SnO2 varistors still have the problems of large leakage current and relatively low nonlinear coefficient. For the low leakage current and high nonlinear coefficient of the varistors, in this paper, the influence of different amounts of Ni2O3 on the electrical properties and microstructure of SnO2·MnO2·ZnO·Ta2O5 system was studied. The formation mechanism of the electrical characteristics of SnO2 varistors was studied by measuring current-voltage, SEM, capacitor-voltage, X-ray diffraction and ac impedance spectra of the samples. It was found that the electrical characteristics of the samples were the best (the voltage gradient was 563V/mm, the leakage current was 8.87 μA/cm2, the nonlinear coefficient was 38.5), when 0.2 mol % Ni2O3 was added. This study has reference significance for exploring SnO2 varistor with high nonlinear and low leakage current.