Efficient lubrication of alkylated reduced graphene oxide based on tribochemistry

Graphene has been applied to the research of new lubricant additives in the field of tribology because of its excellent properties. However, during the mixing process of graphene and base oil, agglomerated structures are formed due to their incompatibility, and this phenomenon limits the full play of its advantages. In the face of this challenge, this paper designs a simple and efficient octadecyltriethoxysilane modified reduced graphene oxide (rGOOES) nanolubricant through a three-step process, including the synthesis, functionalization, and chemical reduction of GO, to meet the future needs of oil-based interface lubrication. The morphological and structural characteristics of rGOOES nanosheets were studied by scanning electron microscopy, X-ray photoelectron spectroscopy, Fourier infrared spectroscopy and thermal weight loss analyzer, and the dispersion stability and tribological properties of rGOOES nanofluids were investigated by particle size distribution method and four-sphere method, respectively. According to the findings, the outcomes demonstrated that the procedure had the ability to augment the stability of rGOOES nanosheets’ dispersion and ensured their uninterrupted delivery to the contact interfaces of the steel ball friction pairs. Macro tribological experiments confirmed that the blend with rGOOES (0.01 wt%) exhibited significant friction and wear reduction compared to the base oil, reducing the coefficient of friction by 22.1% and the wear scar diameter by 24.8% of the steel ball friction pairs. The mechanism analysis indicated that this improvement in lubrication properties was attributed to the high dispersion of rGOOES nanosheets and the reorganization of the sliding interfaces, as well as the protective film formed on the friction interfaces of the steel balls. Thus, this work provides a practical application of two-dimensional nanomaterials in the field of lubrication.