Zino Oxide Varistors Made from Powders Prepared by Amine Processing

A powder preparation process suitable for varistor production was developed. The mixed acidic solution containing varistor components was added to the diethylamine solution to coprecipitate all components. The resulting mixtures were washed, dried, and calcined to produce active and uniform composition powders. Large nonlinearity coefficient (α∼ 50) were achieved in varistors fabricated from these powders by sintering in the entire range 1100° to 1250°C. Large breakdown fields were also achieved with decreasing sintering temperature. The breakdown voltage per grain boundary of these varistors was approximately 5.2 V.