Comparison of graphene as an oil additive with conventional automotive additives for the lubrication of steel and DLC-coated surfaces
J. Kogovšek, Mitjan Kalin
Abstract
The present work is focused on comparing the tribological behaviour of graphene platelets and commercially available automotive additive package, combined with glyceryl isostearate (GIS) as a friction modifier. The investigation was performed with steel/steel and DLC/DLC contacts, at 25 °C and 100 °C, in all lubrication regimes and by considering the running-in effect. Under all the investigated conditions the graphene platelets provided the lowest friction in the ML and BL regimes. This is the result of forming graphene-based tribofilms which, unlike for the other tested lubricants, is relatively insensitive to temperature, tribochemical activation and the conditions before or after the running-in. By combined the use of graphene platelets and conventional additives some interactions in their tribological behaviour were also observed.