Preparation and Electrical Characteristics of Novel AgZrB2 Contact Materials

The novel AgZrB2 electrical contact materials with different ZrB2 contents were prepared by the combination method of ultrasonication, ball milling, and spark plasma sintering, and the arc erosion and material transfer behavior were investigated by the electrical contact tests. The results show that the ZrB2 content significantly affects the arc erosion resistance of AgZrB2 electrical contact materials. The Ag-3wt% ZrB2 contact material presents the stable make/break-arc energy and duration, indicating the excellent arc erosion resistance. However, the increased ZrB2 content results in higher make-arc energy and longer make-arc duration with large fluctuations of break arc energy and duration, leading to the severe arc erosion. This result suggests that the excessive ZrB2 is not beneficial to the enhancement of arc erosion resistance. Moreover, it is found that the Ag-3wt% ZrB2 and Ag-5wt% ZrB2 contact materials have the same material transfer mode from anode to cathode, whereas the Ag-7wt% ZrB2 contact material has the opposite transfer mode from cathode to anode.