Lubrication for macroscopic friction pairs with single-layer graphene coating

Abstract

With its strong mechanical properties, graphene has shown potential in applications for reducing friction and wear, but the underlying mechanisms for its macroscopic lubrication remain relatively unexplored. Here, we systematically study the lubrication effect of chemical vapor deposition graphene coated on the surfaces of macroscopic friction pairs made of different materials. Our findings reveal an apparent lubrication by single-layer graphene coating, as well as correlation between the COF and the brittleness of the substrate. Through a comprehensive characterization using Raman spectroscopy, we propose a protective mechanism by which graphene can effectively dissipate the resulting shear stress generated during friction and delay the wear generation until the graphene layer fails and the bare material surface starts to rub directly, which is confirmed by finite element analysis simulation. We believe our results can provide important support for the practical application of graphene coatings in lubrication for macroscopic friction pairs in industrial equipment.