Constrained sintering and wear properties of Cu-WC composite coatings

Coatings of metal matrix composites (Cu-WC) were fabricated by solid-state sintering. WC reinforcing particles in different quantities from 5% up to 30% (volume fraction) were mixed with Cu particles. After mixing, the powders were poured onto the surface of copper substrates. Sintering was carried out at 1000 °C under a reducing atmosphere in a vertical dilatometer. Sintering kinetics was affected by both rigid substrates and WC particles which retarded the radial and axial densification of powders. However, the coatings were strongly attached to the substrate, and WC particles were randomly distributed within the matrix. The addition of the reinforcing particles enhanced the microhardness and reduced the volume loss in wear tests to 1/17 compared to the unreinforced sample. The predominant wear mechanism was identified as abrasion at a load of 5 N. 20% WC (volume fraction) reinforcing particles led to the maximum values of properties for the composite coating.