Friction properties of two surface-modified MoS2 in rapeseed oil

Purpose The purpose of this study is to evaluate the tribological properties of modified molybdenum disulfide (MoS2) nanoparticles as rapeseed oil (RO) additives under different temperature conditions, with a specific focus on high-temperature performance. Design/methodology/approach Silane coupling agent (KH550) and stearic acid (SA) were used to modify MoS2 to prepare KH550-MoS2 and SA-MoS2 additives. The friction performance (friction coefficient, wear) was evaluated at different temperatures using a four-ball friction and wear tester. Using various characterization techniques such as scanning electron microscopy, energy dispersive spectroscopy, X-ray photoelectron spectroscopy and a three-dimensional surface profilometer, the surface morphology, elemental distribution and chemical state evolution of the friction pair were systematically investigated. Findings At 25°C, SA-modified MoS2 (0.2 Wt.%) reduced coefficient of friction (COF) by 31% versus pure rapeseed oil, delivering optimal friction/wear performance. KH550-modified additive (0.03 Wt.%) decreased COF by 28.9% at this temperature. Critically at 75°C, KH550 maintained significant anti-friction effects with a 58.4% steel ball wear rate reduction and improved surface contact ratio (0.66→0.38). Both additives enhanced lubrication performance across temperatures. The exceptional thermal stability of KH550’s siloxane bonds effectively prevented MoS2 nanoparticle agglomeration under high-temperature conditions. Originality/value Modified MoS2 lubricants demonstrate excellent lubricating performance and effectively reduce COF, providing valuable insights for the practical application of lubricants. Peer review The peer review history for this article is available at: Link to the cited website