Influence of cooling rate on stability of nonlinear properties of ZnO-Pr_6O_(11)-based varistor ceramics

摘要

The microstructure, nonlinear properties, and stability of ZnO-Pr_6O_(11) -based varistor ceramics were investigated with cooling rate in the range of 120-480℃/h. The cooling rate relatively slightly affected the microstructure, the varistor voltage, and the leakage current, whereas strongly nonlinear exponent. The varistor ceramics cooled at 120℃/h exhibited the highest nonlinearity, with nonlinear exponent of 56.8 and leakage current of 1.6 μA. Further, the cooling rate most greatly affected the stability against DC accelerated aging stress. The stability against DC accelerated aging stress with cooling rate was found to be high in order of 480 → 120 → 360 →240℃/h in cooling rate.