Interaction Between Selected MoS2 Nanoparticles and ZDDP Tribofilms

• Published in: Tribology letters 2015-07, Vol.59 (1), p.1-18, Article 26
• Main Authors: Tomala, A., Vengudusamy, B., Rodríguez Ripoll, M., Naveira Suarez, A., Remškar, M., Rosentsveig, R.
• Format: Article
• Language: English
• Subjects: Additives; Atomic force microscopy; Chemistry and Materials Science; Corrosion and Coatings; Corrosion prevention; Electron microscopy; Energy transmission; Friction; Friction reduction; Inorganic fullerenes; Lubricants; Lubricants & lubrication; Lubrication; Machine Elements; Maskinelement; Materials Science; Microscopy; Molybdenum disulfide; Morphology; Nanoparticles; Nanotechnology; Nanotubes; Original Paper; Oxidation; Physical Chemistry; Rhenium; Sludge; Surfaces and Interfaces; Theoretical and Applied Mechanics; Thin Films; Transition metal compounds; Tribology; Wear
• ISSN: 1023-8883; 1573-2711; 1573-2711
• DOI: 10.1007/s11249-015-0552-z

Nanoparticles based on transition metal dichalcogenides (TMD) are considered to hold great promise as boundary lubricating additive/material for improving friction and wear of engineering functional surfaces. However, TMD nanoparticles cannot provide a comprehensive surface protection against oxidation, corrosion or sludge control. Therefore, the current lubricant developments may still have to depend on conventional additives such as zinc dialkyl dithiophosphate (ZDDP), and it is essential to understand the interaction of nanoparticles with such additives in order to explore how these nanoparticles could be commercially employed in fully formulated lubricants. This paper examines the tribological properties of three different nanoparticles: inorganic fullerene-like MoS 2 , rhenium-doped MoS 2 and MoS 2 nanotubes in steel and steel with preformed ZDDP tribofilm surfaces using a pin-on-disc-type tribometer under reciprocating sliding conditions. The resulting tribofilms have been evaluated using scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy, transmission electron microscopy and atomic force microscopy. The results show that although the nanoparticles are able to reduce friction in all cases, the resulting tribofilm composition and morphology, and their lubricating mechanisms are significantly different. The MoS 2 nanoparticles and nanotubes show good synergism with ZDDP, and tribofilms formed from nanoparticles exhibit improved friction and wear properties compared to that typically formed from ZDDP.