Various MoS2-, WS2- and C-Based Micro- and Nanoparticles in Boundary Lubrication

• Published in: Tribology letters Vol. 53; no. 3; pp. 585 - 597
• Main Authors: Kogovšek, J., Kalin, M.
• Format: Journal Article
• Language: English
• Published: Boston Springer US 01-03-2014; Springer Nature B.V
• Subjects: Additives; Boundary lubrication; Chemistry and Materials Science; Contact pressure; Corrosion and Coatings; Friction; Fullerenes; Lubricants & lubrication; Lubrication; Materials Science; Molybdenum disulfide; Morphology; Multi wall carbon nanotubes; Nanoparticles; Nanotechnology; Nanotubes; Original Paper; Physical Chemistry; Platelets; Platelets (materials); Solid lubricants; Surfaces and Interfaces; Theoretical and Applied Mechanics; Thin Films; Tribology; Tungsten disulfide; Nanoparticles; MoS; CNT; Oil; WS; Solid lubricants
• ISSN: 1023-8883; 1573-2711
• DOI: 10.1007/s11249-014-0296-1

Various solid lubricant particles have been experimentally evaluated as possible additives to oils. However, information in terms of a direct comparison of their tribological properties is still missing. In this study, we have compared the tribological properties of seven different solid lubricant micro- and nanoparticles as additives in polyalphaolefin (PAO) oil: MoS
2
nanotubes, MoS
2
platelets (2 and 10 μm), WS
2
nanotubes, WS
2
fullerene-like nanoparticles, graphite platelets (20 μm) and multi-walled carbon nanotubes. The experiments were performed in the boundary lubrication regime under a contact pressure of 1 GPa (Hertz, max) using a ball-on-disc tribotester. In general, the particles significantly decreased the friction and wear compared to the base PAO oil. We found that it was the material of the particles that largely determined their tribological performance. The effect of the size of the particles was much less important, and the morphology (shape) of the particles had little or no influence. We have also investigated the effect of ultrasonication during suspension preparation on particle damage and found that the solid lubricant particles were not notably affected, except the MoS
2
and WS
2
nanotubes, which became somewhat shorter.