The Nonlinear Characteristics of Different Additives Added V2O5-ZnO Varistor

Most commercial ZnO varistors containing Bi2O3 exhibit excellent varistor properties, but they have a few drawbacks due to Bi2O3 having high volatility and reactivity and higher sintering temperature. In this study, V2O5 is added as the varistor forming oxide to lower down the sintering temperature of ZnO varistors for the further developing the chip Varistor array by using the Ag as the inner electrode. It is found that the sintering temperature of V2O5-added ZnO will be lower down to about 600oC. But the addition of V2O5 has no improvement in the electrical characteristics, and they need many additives to obtain the high performance. For that, the nonlinear properties in these Varistors can be improved by incorporation of some oxide additives. Different MnOx oxides (MnO, MnO2, and Mn3O4) and CoOx oxides (CoO and Co3O4)are used as the minor oxide additives. The influences of different MnOx and CoOx oxides on the nonlinear voltage–current density (V-I) characteristics and the nonlinear exponent (α) of V2O5-ZnO varistor will be well developed.