Sol-Gel Materials for Varistor Devices

Abstract

The present chapter deals with a systematic report on `sol-gel ZnO varistors', an area which needs to be much explored in terms of the applications it holds. The book chapter starts with a brief introduction on varistors. Subsequently, a detailed description on the so far adopted conventional preparation methods and chemical synthesis strategies for varistors are presented. Among the many chemical methods, the advantages of employing a sol-gel method for varistor technology are discussed in detail in later sections. A detailed literature survey on the preparation, properties and advantages of sol-gel derived ZnO varistors is provided. The main focus of the study is to highlight the importance of nanoinclusions for high-performance varistors in terms of controlled grain size, improved grain boundary area and homogeneous dopant distribution at the grain boundaries. The chapter concludes with a discussion on the recent research interests on the sol-gel ceramic--polymer varistors and studies on varistor-epoxy, ZnO-PANI, ZnO-PANI-PVA, GaAs-PANI-PE, Si--Polymer varistor composites.