The Surface Chemistry and Tibology of Dimethyl Disulfide on Copper

BRENDAN PAUL MILLER; OCTAVIO JAVIER FURLONG; WILFRED T. TYSOE

Milwaukee

Congreso; 70th Physical Electronics Conference; 2010

University of Wisconin

The sliding copper-copper interfaces for the use in electrical motors provides a particular challenge, due to the need for strong electrical contact but also to keep friction and wear low for better efficiency and to limit failure. This work explores the surface chemistry and frictional properties of dimethyl disulfide on copper surfaces to establish whether it is sufficiently reactive to potentially form a tribofilm at near-room temperatures as required for lubrication of the sliding copper-copper contact in an electric motor. Friction measurements of dimethyl disulfide on copper were performed in a UHV tribometer. Temperature-programmed desorption (TPD), reflection-absorption infrared spectroscopy (RAIRS) and X-ray photoelectron  spectroscopy (XPS) were carried out on both a Cu(111) single crystal substrate and a copper foil, since the latter type of sample was examined in the UHV tribometer rather than single crystal samples. Elemental analysis of the tribological wear track in the UHV tribometer was performed to determine chemical differences between inside and outside of the wear scar using an in situ Scanning Electron Microscope (SEM) gun and a single-pass Auger electron detector.