The Interactions Between Sulfur-Nitrided Layer on Steel Surface and MoDTC Lubricating Additive and Their Effects on Tribological Performance

Low temperature ion sulfuration and ion nitriding technologies were used to treat AISI 52100 steel. The tribological behaviors of the treated surface were investigated under lubrication with different MoDTC additive concentration. The morphologies and composition of worn surfaces were observed, and the valence states of tribofilm were identified. The results showed that the sulfur-nitrided surface was obviously improved in the friction-reducing property and exhibited the best synergistic effect when the concentration of MoDTC reached 1.0 %. The main reason is that MoS 2 and FeS were formed on the worn sulfur-nitrided surface.