Electric characteristics of ZnO-varistors sintered at low temperature

Disc-type ZnO varistors were sintered at temperatures ranging from 800°C to 1100°C. A mixture of (1-x)Bi2O3+x&middotSb2O3 was pre-fired at 555°C and added to ZnO powder together with other additive oxides. The electric response of the material thermal treated at 700°C for 1 hour was analyzed. Such heat treatment did not change the varistor voltage significantly, but the nonlinear parameter value (1mA α 0.01mA). The extent of its variation was function of the composition ratio and sintering temperature, excepting the composition range 0.1 &le × &le 0.4. Arrestor-type varistors were prepared in bulk and their electeic characteristics are reported.