Enhanced mechanical and electrical performance of Ag-4wt%ZrB2 contact materials prepared with different-sized Ag powder

Ag-ZrB2 composite is a promising candidate used as electrical contact materials. So far, the effect of Ag particle size on the microstructure, properties and arc erosion behavior of Ag-based contact materials is unclear. In this work, the Ag-4 wt%ZrB2 contact materials were prepared with coarse and fine Ag powder utilizing wet mixing and spark plasma sintering. The microstructures and eroded morphologies of the Ag-4 wt%ZrB2 contact materials were characterized, the arc duration/energy, welding force and mass loss were investigated, and the effect of Ag particle size on arc erosion behavior was discussed as well. The results show that the fine Ag powder is beneficial for the uniform dispersion of the ZrB2 in the Ag matrix, and enhancement on the hardness and electrical conductivity. As compared to the Ag-4 wt%ZrB2 contact material prepared with the coarse Ag powder, the hardness and electrical conductivity of the Ag-4 wt%ZrB2 contact material prepared with the fine Ag powder are increased by 66.26% and 32.92%, respectively. Furthermore, the contact material prepared with fine Ag powder has a shorter break-arc duration and lower break-arc energy, as well as a smaller welding force and less mass loss, thereby exhibiting superior arc erosion and welding resistance.