Rare earth doped zinc oxide varistors

摘要

A varistor includes a Bi-free, essentially homogeneous sintered body of a ceramic composition including, expressed as nominal weight %, 0.2-4.0% oxide of at least one rare earth element, 0.5-4.0% Co3O4, 0.05-0.4% K2O, 0.05-0.2% Cr2O3, 0-0.2% CaO, 0.00005-0.01% Al2O3, 0-2% MnO, 0-0.05% MgO, 0-0.5% TiO3, 0-0.2% SnO2, 0-0.02% B2O3, balance ZnO.