Graphene - MoS2 ensembles to reduce friction and wear in DLC-Steel contacts

Abstract

Recent demonstration of two dimensional (2D) solid lubricant materials to minimize friction to unmeasurable levels (superlubricity) and reduce wear at macroscale propelled further research investigations in the direction of exploring their potential in industrially relevant material combinations such as steel and diamond-like-carbon (DLC) in sliding contact. In this study, we have used a combination of 2D materials i.e. Graphene and MoS2 as a solid lubricant to reduce friction and wear in steel-hydrogenated DLC contacts even at high contact pressures and sliding speed. Sliding friction tests conducted under dry nitrogen conditions shows a reduction of friction and wear by 16 and 29 times, respectively as compared to Steel vs H-DLC (baseline) experiments and friction and wear by a factor of 43 and 434, respectively, compared to self-mated steel vs steel experiments. Optical and Raman investigations of the material pairs and the wear debris analysis in TEM indicated the formation of amorphous carbon mixed graphene layers at the sliding interface leading to such dramatic reductions in friction and wear.