Nonlinear electrical properties and DC accelerated aging characteristics of ZnO–Pr 6O 11–CoO–Cr 2O 3–Dy 2O 3-based varistors

Abstract

The nonlinear electrical properties and stability against DC accelerated aging stress of various varistors, which are composed of ZnO–Pr 6O 11–CoO–Cr 2O 3–Dy 2O 3 (ZPCCD)-based ceramics, was investigated as a function of Dy 2O 3 content. The varistors with Dy 2O 3 exhibited a high nonlinear exponent above 30, compared with that without Dy 2O 3. The varistor with 0.5 mol% Dy 2O 3 exhibited the highest nonlinearity, with a nonlinear exponent of 66.6 and a leakage current of 1.2 μA. Furthermore, this varistor showed the high stability, in which the variation rate of varistor voltage, of nonlinear exponent, and of leakage are −1.9, −10.5, and +275.0%, respectively, under DC accelerated aging stress, 0.95 V 1 mA /150 °C/24 h.