STUDY OF ELECTRICAL CHARACTERISTICS AND MICROSTRUCTURE OF ZINC-OXIDE VARISTOR THROUGH RATE-CONTROLLED SINTERING

A computer program has been developed to control the firing process of ZnO varistors. The binder burnout and shrinkage stages are controlled through a closed feedback loop using a i286 based personal computer. The effect of rate-controlled sintering (RCS) on the formation of micr ostructure and simultaneously on electrical characteristics of varisto rs has been studied in arrester block with V-nom=5 kV and a diameter o f 42 mm. Leakage, watt loss and non-linear coefficient has been improv ed and microstructure with low porosity has been achieved by RCS.