Superlubricity on steel at macroscale using Graphene-nanodiamond

Kalyan C. Mutyala^a; Diana Berman^{a, Ϯ}, Ali Erdemir^b; and Anirudha V. Sumant^a;

^aCenter for Nanoscale Materials, 9700 S. Cass Ave, Argonne National Laboratory, Argonne, IL, 60439

^bEnergy Systems Division, 9700 S. Cass Ave, Argonne National Laboratory, Argonne, IL, 60439

^ϮNow at Materials Science and Engineering Department, University of North Texas, Denton, TX, 76207

Abstract
Ability of graphene-nanodiamond (GND) to withstand high contact pressures at the tribological interface providing superlubricity at macroscale on silicon and SiO₂ surfaces through formation of nano-scrolls has been shown previously. In this study, ability of GND as a solid lubricant in achieving superlubricity on a steel surface sliding against /Diamond-like carbon (DLC) counterface  in dry nitrogen atmosphere at high load and high speed conditions is demonstrated.  We have carried out tribological studies in dry nitrogen environments using pin-on-disc tribometer by varying load and speed. We observed an interesting trend in friction and wear with respect to the size of the nanodiamond utilized in graphene-nanodiamond mixture in achieving superlubricity on relatively rough steel surfaces. We have used various characterization techniques including Raman/SEM/EDS to study the evolution of lubrication mechanism and tribolayer formed within a wear track. We show that it is now possible to achieve stable superlubricity on relatively rough steel surfaces, which is very important for various industrial applications.