Oleylamine-modified carbon nanoparticles as a kind of efficient lubricating additive of polyalphaolefin.

The oleylamine (OA)-modified carbon nanoparticles (CPs) with particle sizes of 25-35 nm were synthesized by a facile one-pot pyrolysis method. As the OA molecules were covalently attached on the surfaces of CPs, the CPs exhibited good dispersibility in polyalphaolefin (PAO). Then the tribological behaviors of CPs as the lubricating additives of PAO were investigated in detail. Under the four-ball mode and the load of 392 N, the CPs showed the best friction-reducing and antiwear properties at the optimal concentration of 1.0 wt%. Specifically, in comparison with that of pure PAO, the mean friction coefficient and mean wear scar diameter of the 1.0 wt% CPs/PAO suspension reduced by 47 and 30%, respectively. The friction-reducing and antiwear capabilities of CPs strengthened with increasing load from 200 to 392 N and increasing test time from 240 to 480 min. In addition, the CPs-based additives could work for a long time without weakening the lubrication capability. The synergistic effect of tribofilm, including PAO molecules and the CPs layer, might account for the outstanding friction-reducing and antiwear capabilities of CPs-based additives under boundary lubrication. [ABSTRACT FROM AUTHOR]