Analysis of ZnO varistors prepared by the sol-gel method

A new sol-gel processing method to prepare ZnO-based varistor powders, usin g inexpensive zinc acetate dihydrate, ethylene glycol, n-propyl alcohol and glycerol as starting materials, is presented. Compared to conventional oxi de-mixing techniques, this method yields powders with a more homogeneous di stribution 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 ver y helpful for achieving high breakdown strength. Microstructure and electri cal characteristics of the sintered powders were investigated. (C) 2000 Els evier Science Ltd and Techna S.r.l. All rights reserved.