Sic-Yag Composite Reinforced Ni-Co Alloy Coatings Produced by Hvof Thermal Spray: Characterization and Wear Behaviour at Room and High Temperature

The addition of ceramic reinforced particles is a common strategy to improve the mechanical and wear characteristics of metallic coatings. SiC presents excellent tribological properties, but it tends to decompose during the thermal spray process. To avoid its decomposition, a SiC powder modified with yttrium aluminium garnet (YAG) was used in this study. The SiC-YAG composite powder was incorporated in a Ni-Co based alloy as particle reinforcement, and the survival of the ceramic reinforcement, the microstructure and tribological properties of the SiC-YAG reinforced Ni-Co alloy coatings were studied. The addition of the SiC-YAG composite powder increases the microhardness of the composite coating compared to the Ni-Co alloy due to dispersion strengthening of the ceramic phase. In addition, the wear behaviour at room temperature shows a slight reduction of the coefficient of friction. However, a more notable change occurs in the wear behaviour at high temperature (600 °C)