Abstract:To clarify the effect of SnO₂ particle size on the arc erosion behavior of AgSnO₂ contact material, Ag-4%SnO₂ (mass fraction) contact materials with different sizes of SnO₂ particles were fabricated by powder metallurgy. The microstructure of Ag-4%SnO₂ contact materials was characterized, and the relative density, hardness and electrical conductivity were measured. The arc erosion of Ag-4%SnO₂ contact materials was tested, the arc duration and mass loss before and after arc erosion were determined, the surface morphologies and compositions of Ag-4%SnO₂ contact materials after arc erosion were characterized, and the arc erosion mechanism of AgSnO₂ contact materials was discussed. The results show that fine SnO₂ particle is beneficial for the improvement of the relative density and hardness, but decreases the electrical conductivity. With the decrease of SnO₂ particle size, Ag-4%SnO₂ contact material presents shorter arc duration, less mass loss, larger erosion area and shallower arc erosion pits.

Key words: AgSnO₂ contact materials; SnO₂ particle size; arc erosion; electrical conductivity; hardness