TiC particulate composite coating produced in situ by laser cladding

A composite coating with TiC particles of various shapes and sizes embedded in nickel based alloy has been in situ synthesized by laser melting a precursor mixture of nickel based alloy powder, graphite and titanium powders. The experiment result showed that the coating epitaxially grew from the substrate with excellent bonding between the coating and the carbon steel substrate. The coating is uniform, continuous and free of pores and cracks, and about 0.6 mm thick. The microstructure of the coating is mainly composed of γ-Ni dendrite, a small amount of interdendritic (γ-Ni+M23C6) eutectic, and dispersed TiC particles. The volume fraction of TiC particles and the microhardness gradually increased from the bottom to the top of the coating layer.