Unbalanced magnetron sputtered Ti-Si-N:MoSx composite coatings for improvement of tribological properties

In this work, Ti-Si-N composite coatings incorporated with MoSx were deposited using unbalanced magnetron sputtering. The MoS2 was co-sputtered and served as lubricant element to reduce the wear friction coefficient. The results showed that with a small amount of MoS2 incorporation (less than 5 at.% of Mo), the tribological properties of the as-deposited composite coatings were significantly improved with little influence on their superhigh hardness. Both the friction coefficient and wear rate decreased monotonously with increase of the Mo content. It is interesting to note that for the coating with only about 1 at.% of Mo content, the friction coefficient and wear rate were abruptly reduced to about 1/2 and 1/3 of those without MoS2 incorporation, respectively. When the Mo content was increased up to about 5 at.%, the wear rate of the coating could be reduced to about one tenth in comparison with the coatings without MoS2 co-deposition.