Compositional changes in lubricated sliding metal surfaces related to seizure

This paper presents an investigation into the mechanisms of failure in lubricated sliding metal contacts. Reciprocated sliding with cylinder-on-disc geometry was performed with three types of lubricants based on polyalphaolefin (PAO) oils and three sets of additives. The normal force and sliding speed were chosen to give partial scuffing or seizure within a few hours. The chemical surface films which form through reactions between additives in the lubricants and the metal surfaces were analysed by scanning electron microscopy and Auger electron spectroscopy, before and after the onset of seizure. It is concluded that all three oils formed a rigid surface film as a result of a combination of chemical and mechanical actions in the contact surface. Seizure was initiated by mechanical fatigue and disruption of the film which exposed the metal surfaces to severe scuffing. It Was Also Noticed that different additives gave different friction and wear properties to the contact system.