Ti-Si-B-N coatings were deposited on AISI 304 substrates by plasma enhanced chemical vapor deposition using a gas mixture of TiCl4, BCl3, SiH4, N2, H2, and Ar. Coatings with different Si and B contents were obtained by varying the gas ratio of BCl3/ SiH4. The Si-free Ti0.75B0.25N coating exhibited nanocomposite microstructure of Ti (B, N) crystallites and amorphous BN phase. With increase of Si in the coatings, the nanocomposite microstructure consisting of nano-sized (Ti, Si)(B, N) crystallites and amorphous BN/Si3N4 tissue phase was obtained in the coatings. The microhardness of the Ti-Si-B-N coatings increased from ~38 GPa for the Ti0.75B0.25N, and then decreased with further increase of Si content in the film. All the Ti-Si-B-N coatings exhibited friction coefficient less than 0.5. The Ti0.74Si0.04B0.21N coatings showed the lowest average friction coefficient of 0.4. The relationship between chemical composition, microstructure and properties of the Ti-Si-B-N coatings were discussed.
Keywords: Ti-Si-B-N, Nanocomposite, PECVD, Multi functional, Friction coefficient