Solid-Liquid Composite Lubricating Coating from Thermally Sprayed Ceramic Template: Tribological Properties, Lubrication and Failure Mechanism

Abstract

A novel solid-liquid composite lubrication coating was prepared using the inherent pores and micro-cracks of thermally sprayed Al2O3/polyfluoroalkoxy coating. Results suggest that nano-scaled Al2O3 and polyfluoroalkoxy abrasive debris were encapsulated by perfluoropolyether and generated as micro-convex at friction interfaces. The micro-convex exhibits a high adhesion force (119 nN), thereby preventing crack propagation on the worn surface. By creating a micro-convex surface, a minimal friction coefficient of 0.07 is achieved, leading to a reduction in wear rate of approximately 79% when compared to pre-oil immersion conditions and approximately 99% when compared to Al2O3 coatings. Continuous consumption of perfluoropolyether and accumulation of wear debris during sliding leads to gradual destruction of the lubricating micro-convex, ultimately leading to its failure.

Keywords: Thermally sprayed technology, Al2O3/PFA/PFPE coating, Solid-liquid composite lubrication, Lubrication mechanism