Paper VIII (ii) Wear Debris Agglomeration in Dry and Boundary Lubricated Sliding

Abstract

A combined experimental and analytical study showed that one of the primary roles of an effective lubricant is to prevent wear particle agglomeration, thus reducing the plowing of the interfaces by wear particles. The experimental work consisted mainly of pin-on-disk sliding tests on several material pairs and lubricants, where the friction coefficient and separation of the sliding interface were simultaneously measured. Wear debris size was typically small at the onset of sliding, but later increased due to agglomeration as sliding progressed. When the agglomerate reached a certain size, it became unstable and was removed from the interface. When an effective lubricant was used, however, wear particle agglomeration was either absent or was greatly reduced. An analytical model based on the slip-line field analysis of the agglomerate was used to predict the critical height of the agglomerate at which the wear debris collapsed and was removed.