Various MoS₂-, WS₂- and C-based micro- and nanoparticles in boundary lubrication

J. Kogovšek, M. Kalin

Tribology Letters 53 (2014) 585-597.

Abstract

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 nano-particles as additives in PAO oil: MoS₂ nanotubes, MoS₂ platelets (2 µm and 10 µm), WS₂ nanotubes, WS₂ fullerene-like nanoparticles, graphite platelets (20 µm) and multi-walled carbon nanotubes (CNTs). 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. The size and the morphology of the particles during the preparation of the suspensions using ultra-sonication were mainly preserved, except for some changes with the MoS₂ and WS₂ nanotubes.

Keywords: nanodelci, grafit, mejno mazanje, WS₂, trdna maziva, MoS₂, olje, ogljikove nanocevke

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