Friction Stir Processing (FSP) of Thermal-sprayed Tungsten Carbide-Nickel (WC-Ni) MMC Coating

Tungsten carbide-Nickel (WC-Ni) metal matrix coating with fixed powder composition was deposited using low pressure cold gas dynamic spraying (LPCGDS) and High velocity oxy-fuel (HVOF) spraying. These coatings were subsequently treated with friction stir processing (FSP) as post-deposition heat treatment. The non-FSP and FSP-treated cold-sprayed and HVOF-sprayed WC-Ni MMC coatings were wear test using the standard ASTM G65 dry abrasion test. The aim of this thesis was to investigate the effect of FSP treatment on improvement in wear performance of WC-Ni MMC coating. The results displayed that FSP treatment showed homogeneity and uniformity in microstructure which ensued to improved wear resistance, hardness and toughness of the coating. Scanning electron microscope (SEM) analysis was conducted on the wear-tested samples showed change in wear mechanism from delaminated sheet wear to indentation and scratching due to improved coating toughness.