Zno varistor of low-temperature sintering ability

摘要

Zinc oxide (ZnO) varistors containing vanadium oxide as the principal additive and one or more cobalt oxides and/or manganese oxides additives exhibit excellent nonlinear current-voltage characteristics. Preferably the varistor compositions are capable of being sintered at a temperature of from 900° C. to 950° C. The low-firing capability of the newly developed materials is attractive for the application in the multilayer chip varistor, because it can cofire with the silver (Ag) or palladium/silver (Pd/Ag) internal electrode instead of using the expensive palladium (Pd) or platinum (Pt) metal. With an appropriate combination of ZnO, vanadium oxide (V.sub.2 O.sub.5) and other oxide additives, a varistor sintered at 900° C. for 2 hours is obtained with a nonlinear coefficient 50 and a leakage current 20 &mgr; A/cm.sup.2.