The Fretting Wear Property of Grease Containing Antiwear Nanoparticles Additives

Abstract

First the fretting wear behavior of CuS nanoparticles additives in grease were studied. The results show that the fretting wear volume reduce significantly when CuS nanoparticles additives add to grease. At the same time the existence of sulfid nanoparticles can reduce friction coefficient at the latter fretting time. The results of XPS tests show that Cu, Zn, Ni, S and B elements were founded in the film of wear scar. Secondly the effect of antiwear and oiliness additives on fretting wear behavior of nanoparticles additives in Grease were studied. It was found that when some antiwear, oiliness additives (such as T203, T322, stearyl alcohol or stearic acid) and sulfide nanoparticles were added to urea grease, a synergy effect between the two types of additives made fretting wear volume more small than that of either additive. Based on the results of contrast experiment and some analysis of fretting wear scars, we present the idea that two additives react with friction surface step by step. That is to say, the high chemical activity of CuS nanoparticles decompose first and form protective layer, the heat converted from chemical reaction of CuS decomposition and mechanical motion promote composition of common oil additives, thus protective layer is formed once again and wear volume further decrease.