The Antiwear and Friction-Reducing Performance of Magnesium Silicate Hydroxide/Graphite Nanocomposite as a Lubricant Additive

Abstract In this article, magnesium silicate hydroxide-graphite (MSH-C) and magnesium silicate hydroxide-graphene oxide (MSH-GO) composites were prepared by doping magnesium silicate hydroxide (MSH) with micron-sized few-layer graphene oxide (∼10 µm) and nanoscale graphite (∼300 nm), respectively, during the hydrothermal synthesis process. Octadecyltrimethoxysilane (ODTMS) was used as a surfactant to disperse these two types of additives into the fully formulated oil. Tribological tests demonstrated that MSH-C exhibited superior tribological properties compared to MSH-GO. The findings reveal that the oil sample containing 0.5 wt% MSH-C can effectively reduce wear volume by approximately 26.4% compared to fully formulated oil, with the friction coefficient decreased to ∼0.02. scanning electron microscopy (SEM), Raman, focused ion beam-transmission eletron microscope (FIB-TEM), and time of flight secondary ion mass spectrometry (TOF-SIMS) characterizations, along with molecular dynamics simulation, were used to investigate the tribological mechanism. A tribofilm composed of two layers of different compositions was formed on the worn surface of MSH-C, indicating the synergistic effect of MSH and graphite.