Effect of Impurities on Varistor Properties of High-Voltage ZnO Ceramics

The effect of cationic and anionic impurities on the varistor properties of high-voltage ZnO ceramics with a ZnO content of 75 wt % and a weight ratio of oxides of alloying elements Bi2O3:Sb2O3:Al2O3:Co3O4:NiO = 1.00 : 0.45 : 0.80 : 0.65 : 0.53 has been studied. It was found that anionic Cl–, F–, SO42–, PO43– and cationic Li+, Na+, K+, Cs+ and Mg2+ impurities worsen, while cationic impurities Ca2+, Sr2+, Ba2+ significantly improve the properties of ceramics. With the introduction of 0.3 wt % BaO, ZnO-75 ceramics, promising for the production of high-voltage varistors, were obtained.