Tribological properties of fluorinated carbon nano/micro particles

The tribological properties of fluorinated carbon nano/micro particles were studied using an alternative ball-on-plane tribometer. The investigation of the friction properties of fluorinated carbon nanofibers and nanodisc shows a beneficial influence of fluorination on the lubricating performances of the compounds. The obtained friction coefficients were as low as conventional graphite fluorides for carbon nanofibers (CNF) and graphitized CND2700. In the case of CNF, the fibrous nature of the tribofilms suggested that individual nanofibers play a predominant role in the friction reduction process. The good tribologic performances observed as soon as the F/C ratio reached 0.15 were attributed to the lowering of surface free energy resulting from the complete fluorination of the external graphene layers leading to a lowering of interfibers interactions. The increase of the F/C ratios, resulting from the progressive fluorination of the internal part of the fibers, did not affect the properties of the fibers fluorinated surfaces. This led to the stabilization of interfibers interactions and consequently of the friction coefficients. In the case of carbon nanodiscs, the evolution of friction properties, regarding their initial structure, pointed out that initial long range order (graphitic structure) is a parameter of first order. This is an abstract of a paper presented at the Society of Tribologists and Lubrication Engineers Annual Meeting and Exhibition (Las Vegas, NV 5/16-20/2010).