Self-lubricating antiwear composite coatings were fabricated on Ti6Al4V alloy by laser cladding. The dry sliding wear tests under various temperatures (ambient temperature, 3508C and 7008C) and normal loads (3, 6, 9 and 12 N) were accomplished, and the corresponding wear mechanisms were investigated. Results show that the composite coating presented lower friction coefficient at ambient temperature and 7008C, and the wear rate increased monotonously from ambient temperature to 7008C. The reasons are that the hard phases of TiC and TiWC 2 carbides enhance the wear capabilities at ambient temperature to 3508C. The CrS and Ti 2 CS sulphides have friction reducing effect at 7008C. The friction coefficient decreased and the wear rate increased with the increasing of normal load. It is ascribed to the effects of the CrS and Ti 2 CS sulphides at moderate normal load. It is implied that the tribological property of the composite coating showed the best at ambient temperature and moderate normal load.

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The NiCr/Cr3C2-10CaF2 (wt-%) composite coatings were fabricated on Ti-6Al-4V alloy by laser surface alloying. Ageing treatments were performed at 600°C for 0, 24, 48 and 96 h, respectively. Microstructure and tribological properties of the as-laser-alloyed and aged composite coatings were investigated systematically. Results showed that microstructure became more homogeneous after ageing at 600°C for 48 h. Wear rates and friction coefficients of the aged composite coatings were slightly higher than that of the as-laser-alloyed coating. It indicates that microstructure and tribological properties of the composite coatings present good high-temperature stability.