Effect of Al2O3 Content on Electrical Breakdown Properties of Al2O3/Cu Composite

Al2O3/Cu composites were prepared by external addition of Al2O3, and the effect of Al2O3 content on microstructure, density, hardness, electrical conductivity and vacuum electrical breakdown properties was studied. The results show that with increasing Al2O3 addition, the density of Al2O3/Cu composite significantly decreases, the hardness sharply increases and then slowly decreases, but the electrical conductivity invariably decreases. The vacuum breakdown test shows that with increasing Al2O3 addition, the breakdown strength first sharply increases and then decreases when the Al2O3 content exceeds 1.2 wt.%; the chopping current always exhibits a decreasing trend and the arc life first increases and then decreases. According to the morphology of arc erosion and analysis, the arc erosion resistance increases and then decreases sharply. In the range of experiments, the optimal arc erosion resistance of Al2O3/Cu composite can be obtained with the addition of 1.2 wt.% Al2O3.