The invention provides a high-performance direct-current
zinc oxide varistor and a preparation process thereof. The
varistor is prepared from the following components in parts by mol: 90 to 98 parts of ZnO, 0.5 to 7 parts of Bi2O3, 0.1 to 10 parts of Sb2O3, 0.1 to 2 parts of Co2O3, 0.1 to 5 parts of SiO2, 0.1 to 5 parts of MnO2, 0.1 to 5 parts of Cr2O3, 0.1 to 4 parts of NiO, 0.1 to 1 part of B2O3, 0.01 to 0.6 part of Al(NO3) 3.9HO, 0.01 to 0.5 part of V2O5, 0.01 to 0.5 part of CeO2 and 0.05 to 0.5 part of silver glass
powder. According to the
varistor and the preparation method thereof, by adding B2O3, V2O5, CeO2 and silver glass
powder in a traditional varistor, and by
coating a varistor blank surface with
bismuth-containing
oxide during high-temperature firing and by carrying out direct-current
coating and
diffusion treatment on the varistor obtained by high-temperature firing according to the preparation process, various performances, such as
aging resistance, rectangular wave current
impact tolerance stability and large current
impact tolerance stability of the varistor can be greatly improved, and the preparation process has the advantages of low cost, high efficiency and the like.