High performance varistor discs obtained from chemically synthesized dopedzinc oxide powder

The ceramic microstructure, the chemical homogeneity of specific dopants an d the mechanical integrity of a varistor disc are critical parameters in de termining the transient voltage suppression features of these devices. The material properties and overall quality of the starting ceramic powders use d to produce such components are essential in achieving the desired propert ies. The present work describes a novel chemical method developed to produc e doped zinc oxide powders and an industrial scale manufacturing process fo r the production of final varistor blocks for surge arrester applications. The results are compared with those obtained when using standard varistor p owder made by the mixed oxide route is used. All the fundamental electrical properties of the discs have been determined and correlated with the relev ant manufacturing steps.