An Experimental Investigation on Tribological Behaviour of Polyalphaolefin (PAO4) Oil Modified with Cu/MnS Nanocomposites

The tribological behavior of Polyalphaolefin oil (PAO4) with the inclusion of Cu/MnS nanocomposites was investigated experimentally and compared with the behavior of the base oil operating with individual Cu and MnS nanoparticles. Cu/MnS nanocomposites with an average size of 98 nm were synthesized and used as additives in PAO4 base oil with concentrations of 0.2, 0.4, 0.6, 0.8, 1.0, and 1.2 Wt%. Using a standard four-ball testing machine, the tribological properties of oil containing Cu/MnS nanocomposites were examined between steel/steel contacts. Using the friction torque data, the Coefficient of Friction (COF) was determined. A Scanning Electron Microscope (SEM) was used to analyze the Wear Scar Diameters (WSD) of the balls, which were also equipped with an Energy-Dispersive X-ray spectroscope (EDX). PAO4 oil with Cu/MnS composites shown a better tribological performance than oil with mono nanoparticles. Also, among all samples, base oil with 0.6 wt. % concentration of Cu/MnS nanocomposites yielded excellent results. The COF decreased by 69.7%. The decrease in friction coefficient is due to the formation of a protective layer as a result of nanoparticles deposition on the rubbing surfaces. The wear behavior was modified due to the change during the frictional process from sliding friction to rolling friction.