Influence of a Succinimide Dispersant on the Tribological Performance of MoS2 Nanoparticles.

In this study, the effect of a polyisobutenyl succinimide (PIB) dispersant on the tribological performances of MoS2 nanoparticles used as lubricant additives in a PAO base oil was investigated. Friction tests were conducted in boundary lubrication regime, in a steel/steel sliding contact configuration, at room temperature and at 100 °C. The tribofilms formed on the rubbed surfaces were analyzed using X-ray Photoelectron Spectroscopy (XPS) and Transmission Electron Microscopy (TEM). The results show that the dispersant used in this work prevented the agglomeration/sedimentation of the nanoparticles and strongly improved their dispersion in the base oil. Its effect on the tribological performance of the nanoparticles was found to be temperature dependent. The best friction-reducing properties were obtained at elevated temperature. It was also found that the dispersant strongly affected the tribofilm's properties (chemical composition, thickness, MoS2 flake length) and that the best reducing friction properties were obtained when the tribofilm was composed of long and well-dispersed MoS2 flakes aligned in the sliding directions. [ABSTRACT FROM AUTHOR]