Structure vs chemistry: Tribological behavior of TiN films in the nitrogen atmosphere

Abstract

Traditional view holds that transition metal nitride films have high friction coefficient and difficult to regulate. It is very challenging to obtain low friction consumption, which limits their wide application. Here, the tribological behavior of TiN films prepared by multi-arc ion plating and GCr15 steel balls under nitrogen atmosphere have been systematically investigated. It is interesting that TiN film in an alternating atmosphere shows a good adaptability similar to that of H-DLC films in the atmosphere of nitrogen. Specifically, the friction coefficient is higher in vacuum, but lower in nitrogen atmosphere. The multi-cycle variation in the frictional environment confirms the adsorption of nitrogen molecules at the sliding interface. The X-ray photoelectron spectroscopy results from the wear tracks show the formation of oxide and the adsorption of nitrogen at the sliding interface. In addition, the synergistic mechanism of N2 molecule as electron donor and electrostatic repulsion and nitrogen atoms and tribo-transfer film was established. It provides a general strategy for the regulation of hard films in nitrogen atmosphere.