Abstract
A conventional ceramic processing method was applied to manufacture high‐density 20‐nm ZnO‐Bi2O3‐Mn2O3 varistor ceramics. Different cooling rates in the range of 135–540°C/h led to a relatively slight influence on the microstructure, varistor voltage, and leakage current. In contrast, these rates strongly affected the nonlinear exponent. The specific surface area of the 20‐nm ZnO nanoparticle may have led to an intense solid‐state reaction even at a low cooling rate. Superior nonlinearity, with 59.7 μA nonlinear current leakage and 273.5 μA leakage current, was achieved at the 135°C/h cooling rate. The differences in the cooling rates led to a remarkable change in the material's stability under direct current (DC)‐accelerated aging stress in the following order: 135°C/hr ˃ 270°C/hr˃405°C/hr ˃ 540°C/hr.
Varistors were fabricated using the traditional ceramic processing method with different cooling rates
Variations in the cooling rates strongly impacted the nonlinear property stability under the DC‐accelerated aging stress conditions.