9th International Conference on Smart Materials and Structures
Argonne National Laboratory, USA
Title: Nanoscale tribochemical reaction drive superlubricity at macroscale with 2D materials-nanoparticles ensembles
Biography: Anirudha V Sumant
In our previous studies we have demonstrated that the new super lubricity mechanism at macroscale by combined uses of graphene mixed with nanodiamonds sliding against diamond-like carbon (DLC). In particular, we showed that super low friction regime (the coefficient of friction is 0.004) is observed when graphene patches wrap around the nano diamonds and form nanoscrolls with reduced contact area sliding against an incommensurate DLC surface. In the present study, we show that other two dimensional (2D) layered material such as molybdenum disulfi de (MoS) is also capable of demonstrating super lubricity through unique tribochemical reaction with carbon leading to formation of onion-like carbon (OLC) at the tribological interface. We have observed that beyond some initial run-in period, the friction comes down to some unmeasurable levels and maintains in that state for a very long period of time, despite the fact that introduced 2D film of MoS is only a few nanometer thick. Our detailed experimental and theoretical investigations suggest that formation of OLCs is possible through tribochemical reaction with these 2D materials that could occur at the tribological contact due to high contact pressure. Th ese OLCs behaves in a similar way described earlier in our previous studies, providing reduced contact area and incommensurability with respect to the sliding DLC surface leading to super lubricity. We will discuss the detailed mechanism and highlight the similarities and diff erences with the previously demonstrated super lubricity involving graphenenanodamond ensembles. Th is new discovery broadens the fundamental understanding of frictional behavior of 2D materials beyond graphene and opens a wide range of possibilities for implementing them in mechanical and tribological applications involving static, sliding, and rotating contacts.