Molecular mechanisms for the functionality of lubricant additives.
Wear limits the life-span of many mechanical devices with moving parts. To reduce wear, lubricants are frequently enriched with additives, such as zinc phosphates, that form protective films on rubbing surfaces. Using first-principles molecular dynamics simulations of films derived from commercial additives, we unraveled the molecular origin of how antiwear films can form, function, and dissipate energy. These effects originate from pressure-induced changes in the coordination number of atoms acting as cross-linking agents to form chemically connected networks. The proposed mechanism explains a diverse body of experiments and promises to prove useful in the rational design of antiwear additives that operate on a wider range of surface materials, with reduced environmental side effects.
Mosey
Nicholas J
NJ
Department of Chemistry, University of Western Ontario, London, Ontario, Canada, N6A 5B7.
Müser
Martin H
MH
Woo
Tom K
TK