Superior tribological performance of electrophoretically deposited multi-layer Ti3C2Tx coatings induced by a dynamically stable lubricating system

Abstract

Due to the superior tribological performance induced by their ability to form lubricious tribo-layer, multi-layer MXenes are considered promising next-generation solid lubricants. However, the formation mechanism of the tribo-layer and its connection with the frictional evolution have not yet been fully explored and understood. In this study, the tribological performance of electrophoretically deposited Ti3C2Tx coatings was assessed by reciprocating ball-on-disk tribometry. Under a contact pressure of 0.84 GPa, the MXene coating exhibited notable reductions in friction and wear rate by factors of 4.8 and 38, respectively. The detailed investigation of the wear tracks confirmed the formation of two different types of tribo-layers, namely a thin nano-porous and a thick densified tribo-layer, which helped to form a dynamically stable lubricating system thus inducing a superior solid lubrication performance. Their formation mechanisms were investigated through nanoscale microstructural and chemical analysis thus shedding light onto the correlation between the observed frictional behavior and the underlying tribo-layer formation process.