Diamond-derived carbon onions as lubricant additives

Among all the new carbon forms like fullerenes or nanotubes, carbon onions are of particular interest for tribological applications because of their spherical and tiny shape, and their chemical inertness. Used as additives blended to a synthetic base oil, they present excellent anti-wear and friction-reducing properties. In this paper, we compare tribological performances of two kinds of carbon onions with different structural features. Due to the synthesis method used, carbon onions present or not a residual diamond core inside the graphitic shells. Carbon onions without the diamond core present better anti-wear properties.