Identifying lifetime determining processes in third-body controlled, abrasive contacts

Abrasive wear of hard coatings in oscillatory tribological contacts is investigated. Under dry conditions the removal of material is frequently governed by third body abrasion. A crucial role plays the distribution of these particles inside the contact. A detailed analysis of the topography of wear tracks after short testing routines is used to extract the underlying mechanisms of particle abrasion with the goal to predict the lifetime determining process of the coating. A numerical model is presented that considers the evolution of the abrasion particle distribution inside the contact. The developed model is used to describe tungsten carbide coatings under oscillatory load using spherical counterbody. Considering particle motion towards the edges of the wear track it is possible to model the observed wear profiles with high accuracy. As proof of concept a comparison to hard coatings with increased surface roughness is performed where particle motion is suppressed. As a consequence, significantly modified wear tracks are found. Having identified the role of the redistribution process for the abrasion it is possible to extrapolate the found description of abrasion towards larger durations of mechanical exposure. It is found that the end-of-life-process changes for different tribological contacts under varying testing conditions. Even a change of the lifetime determining process can be observed in case of long and extensive load.