Molybdenum disulphide in lubrication. A review

Microtribology and Friction-Induced Material Transfer in Layered MoS2 Nanoparticles Sprayed on a Steel Surface

“…The change represents its thermal decomposition and the *20% weight loss in this temperature range is consistent with a conversion of MoS 2 to MoO 3 and gaseous SO 2 as reported previously [2,45,46]. This oxidation of MoS 2 by heating in air is believed to be dependent not only on temperature, but also on the particle size and availability of air [40]. For the 50 nm MoS 2 particle used in this study, the thermal decomposition starts at temperature 250°C and we observe *30% weight loss in the 250-500°C temperature range.…”

“…A reduction in size on the one hand may facilitate a better distribution and transport of the particle in the medium. On the other hand, a size reduction may give rise to agglomeration [38,39] and easy oxidation [40], phenomena, which are known to be detrimental to tribology [38,39] as they enhance both friction and wear. Figure 1 reports microtribometric experiments done in a ball-on-flat configuration, the contact lubricated by MoS 2 suspended in hexadecane oil.…”

A review of recent developments of friction modifiers for liquid lubricants (2007–present)

“…Due to the (9), ester (10)(11)(12)(13)(14)(15)(16)(17)(18), ketone (19,20), mercaptocarboxylate (21,22), thioester (23) and carboxylate (24,25).…”

“…Due to its special lamellar-type structure and low shear strength, MoS 2 is a very useful lubricant additive that provides excellent friction reduction especially in high-pressure contacts, and a number of papers have been published [15][16][17][18][19]. Zhou et al reported that the MoS 2 microspheres exhibited much better extreme pressure, anti-wear and friction reduction properties in base oil than commercial colloidal MoS 2 [20].…”

Friction

“…The low friction of MoS 2 does not depend on adsorbed vapor and is, therefore, an intrinsic solid lubricant (Peterson and Johnson, 1953;Braithwaite, 1964, Winer, 1965Clauss, 1972;Holinski and Gansheimer, 1972;Farr, 1975;Sliney, 1982;Bhushan and Gupta, 1997). Like graphite, MoS 2 forms an oriented film on a sliding surface, with the basal planes tending to be aligned parallel to the surface; bonding of the crystallites to the surface is probably aided by the internal polarization of the lamellar which results from their sandwich structure.…”