Major effect on electrical properties and aging behavior of ZnO–Pr6O11-based varistor ceramics with small In2O3 doping changes

Abstract

The effect of In2O3 doping on microstructure, electrical properties, and DC-accelerated aging behavior of the ZnO–Pr6O11-based varistor ceramics was systematically investigated. The addition of In2O3 did not significantly alter the sintered density increasing in the small range of 5.60–5.63 g/cm3 and the average grain size decreasing in the small range of 3.4–2.9 μm. However, the incorporation of In2O3 pronouncedly increased the breakdown field from 6,023 to 14,822 V/cm. Furthermore, the incorporation of In2O3 markedly improved the nonlinear coefficient (45 at 0.005 mol% In2O3) and it saliently suppressed the leakage current density (7.3 µA/cm2 at 0.005 mol% In2O3). In2O3 acted like the role of acceptor due to the donor concentration, which decreases in the range of 1.02 × 1017–0.24 × 1017 cm−3 with an increase in the content of In2O3. The ceramics added with 0.005 mol% In2O3 exhibited an excellent stability, with %ΔE1mA = 0% and %Δα = −2.2% under DC-accelerated aging stress state of 0.85 E1mA/115°C/24 h.