Er2O3 Doping Effect on Varistor Properties and Multiimpulse Stress Behavior of ZnO–PrO1.83–CoO–Cr2O3–Dy2O3 Ceramics

Abstract

The Er2O3 doping effects on varistor properties and impulse aging behavior of the ZnO–PrO1.83–CoO–Cr2O3–Dy2O3 ceramics were investigated in the range of 0–2.0 mol%. The nonlinear coefficient increased from 42 to 56 with an increase in the amount of Er2O3. The clamp voltage ratio (K) decreased with an increase in the amount of Er2O3. The varistors doped with 2.0 mol% in the amount of Er2O3 exhibited the best clamping characteristics, with K = 1.43–1.83 at an impulse current of 1–50 A. The varistors doped with 0.25 mol% in the amount of Er2O3 exhibited the strongest electrical stability, with the variation rate of the breakdown field of −0.5%, the variation rate of the nonlinear coefficient of −5.5%, and the variation rate of the leakage current of −1.5% after applying 400 times at an impulse current of 400 A