Improving dispersion and tribological performance of MoS2 lubricant additive with the synergistic effects of MSH and amorphous carbon

Abstract

The poor dispersion stability and susceptibility to oxidation significantly restrict the practical application of MoS2 as a lubricant additive. Here, MoS2 nanocomposite powders with magnesium silicate hydroxide (MSH) reinforcement and amorphous carbon protection were prepared via a straightforward two-step procedure. Detailed studies of the structure, phase composition, tribological properties, and lubrication mechanism of the composite powder have been conducted. The results demonstrated that the morphology of the composite powders was rod-shaped MSH coated with amorphous carbon and layered MoS2. The introduction of amorphous carbon into the MSH/MoS2 composite powders results in enhanced dispersion and a reduction in corrosion to copper sheets. Furthermore, the addition of 1.0 wt% MSH/MoS2/C nanoparticles to PAO-6 led to a decrease in the COF of the lubricating oil from 0.104 to 0.063. Meanwhile, the wear rate of the friction pair decreased from 5.91 × 10−7 mm3 N−1 m−1 to 2.22 × 10−7 mm3 N−1 m−1. The excellent performance could be attributed to the introduction of amorphous carbon effectively prevents the oxidation of MoS2 within the additive, leading to improved friction and wear resistance. The tribo-film, composed of MSH, Fe2O3, FeS, MoS2, graphite, and amorphous carbon, demonstrates remarkable capabilities in reducing friction and wear.

Keywords

• Magnesium silicate hydroxide
• MoS2
• Amorphous carbon
• Friction and wear
• Lubrication mechanism