The Influence of Sintering Technology on the Energy Absorption Capability of ZnO Varistors

Research has shown that during the sintering process, zinc oxide varistors often develop pores, particularly in the edge regions. These edge pores can cause electric field distortion and inconsistent energy partition, which in turn diminishes the storage ability of the varistors. In this paper, we introduce a highly permeable repair medium designed to address this issue. By utilizing a secondary densification process, new grains are encouraged to grow within the open pores located at the edges of the varistors. The capability of ZnO varistors to outlast a 2 -millisecond square pulse current is a critical measure of their energy absorption capacity. This research examines the influences of secondary sintering temperature and duration on the repair medium’s effectiveness through energy tolerance tests, which are conducted using a digital source meter. Scanning electron microscopy (SEM) observations of the samples further validate the feasibility and efficacy of the proposed repair medium.