Analysis of ZnO varistors prepared by the sol-gel method

A new sol-gel processing method to prepare ZnO-based varistor powders, using inexpensive zinc acetate dihydrate, ethylene glycol, n-propyl alcohol and glycerol as starting materials, is presented. Compared to conventional oxide-mixing techniques, this method yields powders with a more homogeneous distribution of dopants; the sintering temperature could be lowered by about 200 K to 1000 degrees C and the grain size is much smaller which proves very helpful for achieving high breakdown strength. Microstructure and electrical characteristics of the sintered powders were investigated. (C) 2000 Elsevier Science Ltd and Techna S.r.l. All rights reserved.