Abstract: Low temperature ion sulfuration was used to treat 52100 steel in order to improve its wear-resistance and anti-scuffing property. Two different sulfur-containing extreme pressure and anti wear additives were used to examine their synergistic effects with FeS layer. The tribological properties were investigated on a ball- on- disk sliding friction and wear tester. SEM was employed to analyze the morphologies of worn surface, and XPS was adopted to identify the valence state of typical elements of boundary lubricating film and detect the depth Profile of elements. The results showed that sulfide layer on the surface prevented the additive and the substrate from direct contact and inhibited the effect of additive. The solid-liquid composite lubrication possessed an obvious synergistic effect when the duration of FeS layer was long. The sulfllr-containing additives reacted with substrate to form FeS to supplement the loss of sulfide layer in wearing process. This incarnated the beneficial synergistic effect of composite lubrication. Sulfuration olefin (SO) with high activity had better replenishinge effect than that of zinc dialkyl dithiophosphate (ZDDP) whose activity depended on catalysis of temperature.

Key words: low temperature ion sulphuration, friction and wear, additives in lubricating oil

Author: Liu Jiajun, Department of Mechanical Engineering, Tsinghua China University, Beijing100084, China

E-mail: liuyuandong1020@163.com

Tribology, Vol. 29, Issue 6, 2009, 537~545