Scientists at the US Department of Energy’s Argonne National Laboratory have recently discovered that they could substitute one atom-thick graphene layers for either solid or oil-based lubricants on sliding steel surfaces, enabling a dramatic reduction in the amount of wear and friction. New studies led by Argonne materials scientists Dr Anirudha Sumant and Dr Ali Erdemir show that single sheets of graphite, called graphene, work equally well in humid and dry environments. Furthermore, the graphene is able to drastically reduce the wear rate and the coefficient of friction of steel. The marked reductions in friction and wear are attributed to the low shear and highly protective nature of graphene, which also prevents oxidation, tribo corrosion, of the steel surfaces when present at sliding contact interfaces.Current lubricants, such as molybdenum disulfide or boric acid, have disadvantages such as environmentally unfriendly additives, or are environmentally unfriendly themselves. The oil-based lubricants need to be consistently reapplied, producing additional waste. The cost of applying solid lubricant coatings is rather high and, due to finite thickness, they do not last very long and must be reapplied thus increasing cost.On the other hand, a graphene coating can be applied to the surface simply by dipping the surface into a solution containing a very small amount of graphene. The graphene was found to adhere strongly to the surface during the testing. It is interesting to see that even partial coatings are very effective at reducing friction because of the ability of the graphene to reorient itself during initial wear cycles, and can last a considerable length of time providing a low friction during sliding. Additionally, they do not produce any waste.Dr Sumant and Dr Erdemir estimated that the reduced loss of energy to friction offered by new materials would yield a potential energy savings of 2.46 billion kilowatt-hours per year, equivalent to 1.5 million barrels of oil.Dr Sumant said “It is interesting to see how a one-atom-thick material affects the properties at a larger scale. I believe that graphene has potential as a solid lubricant in the automotive industry and, once fully developed, it could have positive impacts on many mechanical applications that could lead to a tremendous savings of energy.”Dr Sumant is associated with Argonne’s CNM, while Dr Erdemir works for Argonne’s Energy Systems Division. Funding came from Argonne’s Laboratory-Directed Research and Development office. The team recently published their findings in two consecutive papers in the high-impact journal Carbon.