Effect of Interface Ni and Ti Films on Antifriction Properties of Nanolayer Thin-Film WS2/g-C Coatings

Model thin-film coatings containing laminar WS2 films and nanometer-thick carbon films are created by the reactive pulsed laser deposition technique. To activate the growth of the graphite-like state, the carbon films (g-C) were deposited on the surface of nickel or titanium films formed between WS2 and g-C layers. It is found that the WS2/Ni/g-C/WS2 coating is apt to manifest a very low coefficient of friction (less than 0.013) in tests in dry air without lubrication. The coating with a titanium interface film does not possess such properties. The structural state of the coating before and after the tribotest was monitored by micro-Raman spectroscopy (MRS). Possible causes of the different behavior of coatings with the chosen metal film catalysts are revealed.