Molybdenum complexes as synthetic additives to lubricating oils

New insights on the decomposition mechanism of Molybdenum DialkyldiThioCarbamate (MoDTC): a Raman spectroscopic study

“…Of these additives, friction modifiers and antiwear additives are of particular importance especially for components operating in the boundary lubrication Molybdenum DialkyldiThioCarbamate (MoDTC) has been used as a friction modifier in engine lubricants since early 1970s. [1][2][3] The friction performance of MoDTC-containing lubricants in steel/steel sliding contacts has been shown to be dependent on contact parameters such as temperature, additive concentration, stroke length, sliding speed and surface roughness. [3][4][5][6][7] Low friction (µ=0.04-0.06) has been observed when tribofilms composed of MoS2, formed from MoDTC decomposition, are present at the tribocontact while high friction (µ=0.1) has been observed when only iron oxides are formed at the tribocontact.…”

Molecular evidence for sulfurization of molybdenum dithiocarbamates (MoDTC) by zinc dithiophosphates: a key process in their synergetic interactions and the enhanced preservation of MoDTC in formulated lubricants?

“…Molybdenum-based compounds have a wide range of applications in chemistry, and are used for instance as catalysts to speed-up chemical reactions [1][2][3] or occur as lubricant additives in automotive applications. 4,5 Among the different molybdenumbased additives, oil-soluble molybdenum dithiocarbamates (MoDTC) have been used as highly effective friction modiers since the early 1970s [6][7][8] in engine lubricants for energy saving. Indeed, MoDTC are able to generate molybdenum disulde (MoS 2 ) at the tribo-contact, thereby providing ultralow friction coefficients which improve fuel efficiency.…”

“…Indeed, MoDTC are able to generate molybdenum disulde (MoS 2 ) at the tribo-contact, thereby providing ultralow friction coefficients which improve fuel efficiency. [9][10][11][12][13][14][15] Different analytical techniques such as X-ray spectroscopy, 16,17 electron diffraction, 18 Raman spectroscopy 19,20 and high-resolution transmission electron microscopy 8 have been employed to detect and to study MoS 2 tribolms. Although numerous investigations have been conducted to explain the mechanisms of MoS 2 formation from Mo-based additives, 9,13,[21][22][23][24][25] the molecular transformations involved in the processes have not yet been completely claried.…”