Three composite coatings were prepared by nitriding-sulfurizing processing of Ti-6Al-4V alloy at different sulfurizing temperatures. The microstructure and phase structure of the coatings were examined by scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. Furthermore, the hardness of the coatings was measured. The effect of the sulfurizing temperature on microstructure of coatings was investigated. The results indicated that the composite coating was mainly comprised of titanium nitrides, titanium sulfides, and titanium. It was found that the phase composition of composite coating changed with the variation of the sulfurizing temperature.

The laser cladding technology was used to prepare the Ti / TiB2 composite coating on the surface of Ti600, and the microstructure and performance test results of the coating obtained under different laser specific energy conditions were analyzed. Studies have shown that the laser cladding coating and the substrate have achieved a good bond, and TiB2 has formed into cellular TiB2 after melting, and further solid solution becomes a whisker structure. The diffused TiC and TiN nuclei in the middle of the coating were fully grown and developed a dense dendrite structure with TiB2 particles. A dual-phase structure of granular TiB2 and many lamellar structures was formed under the coating. When the laser specific energy is 20 kJ / cm2, the coating reaches the highest microhardness of 990HV, nearly 2.5 times the hardness of the substrate. The amount of wear shows a monotonic decrease with the increase of the specific energy of the laser, and the average friction coefficient shows a monotonous decrease as the specific energy of the laser increases.