Microstructure, hardness and electrical properties of silver-based refractory contact materials

The electrical conductivity, hardness and microstructure of Ag–W and Ag–WC refractory contact materials have been investigated. Ag–W composites containing 30, 35, 45 and 85 wt.% of silver and Ag-40 wt.% WC composite produced by powder metallurgy were used for this investigation. The effect of graphite addition on hardness and electrical conductivity of Ag–WC composite was also evaluated. The present results show that the electrical conductivity of Ag–W composite increased with increasing Ag content, but decreased its hardness. The addition of WC to Ag increased its hardness, but decreased its electrical conductivity as compared with the addition of W to Ag. The addition of 3 wt.% C to Ag-37 wt.% WC composite decreased both its hardness and electrical conductivity.