An Investigation of Wear Mechanisms for Transfer Films in an In Situ Self-Replenishing Tribosystem

While continuum-based approximations have had success modeling tribosystems with thick film powder flows, they do not predict the behavior of thin powder transfer films which can be worn away from the asperity region during mixed lubrication. This is especially the case for in situ self-replenishing transfer films in the form of compacted solids which are set up to undergo deposition and depletion simultaneously. Although control volume models have been developed to describe this type of tribosystem, very little is known about the wear mechanisms that govern the transfer film in sliding contact. The problem is highlighted through the sudden breakdown of the lubricant film which inevitably leads to interfacial starvation. This study examines evidence that will lead to a fundamental description of the deposition and depletion of powder transfer films by leveraging abrasive wear theory. Justification for this theory is provided by examining the relationship between the coefficient of friction (COF), wear rate, and atomic force microscope (AFM) images of wear interfaces; so that a more accurate model of an in situ self-replenishing solid lubrication process may be constructed.