Investigating the lubrication properties of PAO-4 oil with hybrid graphene oxide/Fe2O3 nanocomposite additives

Abstract

Nanoparticles (NPs) significantly enhance lubrication performance by reducing friction and wear through mechanisms such as the mending effect, rolling effect, and the formation of protective films. Furthermore, combining two or more NPs can lead to the development of new materials that exhibit enhanced performance and increased multifunctionality. This study employed a sonochemical method to synthesize hybrid NPs comprising graphene oxide (GO) and iron oxide (Fe2O3). Subsequently, these NPs were incorporated as additives in polyalphaolefin (PAO-4) oil. Characterization techniques, such as X-ray diffraction, field emission scanning electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, and energy dispersive X-ray spectroscopy, were used to analyze the morphological and chemical properties of prepared hybrid NPs. The nanolubricants (NLs) were prepared by dispersing GO and GO/Fe2O3 NPs in PAO-4 oil. The rheological properties of the developed NLs were assessed using a rheometer at 40 degrees C and 100 degrees C. The tribological tests were also performed on a universal tribometer under different load conditions (5, 15, 25 N). The experimental findings demonstrated that the presence of a hybrid GO/Fe2O3 nano additive enhanced the tribological performance of PAO-4 oil compared to other samples. Notably, the NLs having GO and GO/Fe2O3 NPs exhibited exceptional coefficient of friction (COF) and wear properties compared to base (PAO-4) oil. Raman spectroscopy revealed the presence of a protective GO/Fe2O3 tribofilm on the worn surfaces, contributing to a reduction in the COF and roughness of worn surfaces.