Al doping effect on microstructure, electrical properties, dielectric characteristics, and aging behaviors of ZPCCY-based varistors

Abstract

The Al doping effect on the microstructure, electrical properties, dielectric characteristics, and aging behaviors of ZPCCY-based varistors was investigated in the range of 0.0–0.1 mol%. The breakdown electric field in the E-J characteristics decreased in a wide range from 4,921 to 475 V/cm with increasing amounts of Al2O3. The nonlinear properties were improved by increasing amounts of Al2O3 up to 0.005 mol%, whereas the further additions caused it to decrease. The highest nonlinear coefficient (α = 45.2) was obtained when Al2O3 concentration is 0.005 mol%. The Al2O3 acted as a donor due to the increase of electron concentration in the small range of 0.0–0.1 mol%. On the other hand, an appropriate addition of Al2O3 in the range of 0.001–0.005 mol% was found to significantly improve the electrical stability against DC accelerated aging stress.