Microstructure and tribological properties of plasma sprayed TiCN-Mo based composite coatings

In the present work, TiCN-Mo composite coatings were fabricated by using reactive plasma spraying with the mixture of Ti-graphite aggregates and metal Mo powders under N-2 condition. Results showed that metal Mo strips homogeneously dispersed in lamellar TiCN matrix to generate nearly alternate ceramic-metal composite coatings. Good interface bond were achieved between metal Mo strips and ceramic matrix due to the formation of rim structure. The Mo addition slightly decreased hardness of composite coatings. The hardness distribution uniformity of composite coatings also decreased as Mo content increased (> 10 wt.%). TiCN-Mo composite coatings showed higher friction coefficient than coatings without Mo. TiCN-Mo composite coatings showed improved wear resistance with lower wear rate. Under present sliding wear condition, worn surfaces of TiCN based coatings were covered by thick iron and titanium oxide layer and wear debris contained large amount of oxides, indicating severe adhesive wear accompanied with oxidative wear.