Tribological interactions between TiN PVD coating and MoDTC under boundary lubrication conditions

In this study, the tribological performances of steel/steel and steel/TiN coating systems are investigated under the condition of boundary lubrication by a PAO base oil containing various concentrations of MoDTC. Additionally, the effects of the MoDTC concentration and the contact pressure on the tribochemical decomposition reaction of MoDTC are discussed. In an experiment, a significantly low friction coefficient and wear rate were observed for the TiN coating as compared with the reference steel in the presence of MoDTC in the PAO6 base oil. Moreover, the tribocatalytic effect of TiN coating on the complete decomposition of MoDTC to form a tribofilm containing MoS 2 is discussed. • The tribological performance of TiN coating is evaluated in PAO oil with MoDTC. • The effects of the MoDTC concentration and the contact pressure are discussed. • Low friction coefficient and wear rate were observed for the TiN coating than steel in MoDTC. • The tribocatalytic effect of TiN coating on the decomposition of MoDTC to form a tribofilm containing MoS 2 is discussed.