Arc erosion behavior and mechanism of AgZrO₂ electrical contact materials

In this study, the novel AgZrO2 electrical contact materials reinforced with different ZrO2 contents were successfully fabricated by powder metallurgy. The effect of ZrO2 content on arc erosion resistance of the AgZrO2 electrical contact materials was investigated, and the electrical conductivity and hardness were measured, as well as the arc erosion mechanism was discussed as well. Furthermore, the properties of AgZrO2 electrical contact material were also evaluated as compared to AgSnO2 electrical contact material. The results show that with increase of ZrO2 content, the hardness of AgZrO2 electrical contact materials gradually increases, while the electrical conductivity gradually decrease. The good comprehensive properties can be achieved at 8 wt%ZrO2. The electrical conductivity and hardness of Ag-8 wt%ZrO2 electrical contact material are 72.8%IACS and 77.9 HV, respectively. The AgZrO2 electrical contact materials with less than 8 wt% exhibit lower arc energy and shorter arc duration, as well as outstanding arc erosion resistance. However, an excess ZrO2 content causes obvious fluctuations on arc energy and duration, thereby resulting in more severe arc erosion. As compared to the Ag-8 wt%SnO2 electrical contact material, the Ag-8 wt%ZrO2 electrical contact material presents lower stable contact resistance, less arc energy, shorter arc duration and better interfacial bonding, thus exhibiting excellent resistance to arc erosion.