Novel processing of Ag-WC electrical contact materials using spark plasma sintering

Ag-WC (60-40wt%) contact materials based on three WC particle size powders were doped with 0.1wt% Ni and processed by an appropriate powder pre-treatment followed by spark plasma sintering (SPS). The contacts produced were already bonded to a copper profile during SPS in order to eliminate additional processing steps. The SPS composites had a more homogeneous microstructure and were tougher and softer than the materials produced by conventional press-sinter-infiltration. The infiltrated contacts had a lower arc-erosion whereas the contacts produced by both processes had a similar contact resistance. The microstructure after switching confirmed that the SPS materials had a porous contact surface layer and were crack-free in contrast to their press-sinter-infiltrated equivalents.