Study on Fine Microstructures of ZnO Microvaristors under Over Current Stress

Abstract

ZnO is a fine non-linear material and used in several electrical devices as surge arrestors. ZnO micro particles showed varistor properties. These ZnO micro particles were stressed with over current and their grains and grain boundaries were observed by SEM observations. Over current stress showed changes in the ZnO grain boundaries. We found melted metal oxide on grain boundaries which were not present before the over current stress experiment.