title: Low-temperature, shear-induced tribofilm formation from dimethyl disulfide on copper.
abstract: The frictional properties of a sliding copper-copper interface exposed to dimethyl disulfide (DMDS) are measured in UHV under conditions at which the interfacial temperature rise is <1 K. A significant reduction in friction is found from the clean-surface values and sulfur is found on the surface and below the surface in the wear scar region by Auger spectroscopy. Because the interfacial temperature rise under the experimental conditions used to measure friction is very small, tribofilm formation is not thermally induced. The novel, low-temperature tribofilm formation observed here is ascribed to a shear-induced intermixing of the surface layer(s) with the subsurface region as suggested using previous molecular dynamics simulations. Although the tribofilm contains predominantly sulfur, a small amount of carbon is also found in the film.
authors.affiliation: Department of Chemistry and Biochemistry, and Laboratory for Surface Studies, University of Wisconsin Milwaukee, Milwaukee, Wisconsin 53211, United States.
authors.forename: Octavio J
authors.initials: OJ
authors.lastname: Furlong
authors.forename: Brendan P
authors.initials: BP
authors.lastname: Miller
authors.forename: Peter
authors.initials: P
authors.lastname: Kotvis
authors.forename: Wilfred T
authors.initials: WT
authors.lastname: Tysoe
mesh_terms: D003300:Copper / Q000737:chemistry*; D017276:Friction; D008153:Lubrication; D008422:Materials Testing; D008567:Membranes, Artificial; D033081:Shear Strength; D013440:Sulfides / Q000737:chemistry*; D013499:Surface Properties; D013696:Temperature
chemical_list: D008567:Membranes, Artificial; D013440:Sulfides; D003300:Copper; C004784:dimethyl sulfide