COLL 323 |
| Wilfred T. Tysoe, Feng Gao, and Peter V. Kotvis. Department of Chemistry and Laboratory for Surface Studies, UW-Milwaukee, 3210 N Cramer St, Milwaukee, WI 53211 |
| Chlorinated and sulfurized hydrocarbons react under “extreme-pressure” conditions forming lubricating films of ferrous chlorides and sulfides respectively. The tribological properties of thin films were investigated in ultrahigh vacuum. This strategy eliminates contamination and allows films of known composition and structure to be grown on well-characterized substrates. It is found that a single layer of the film causes a substantial reduction in friction so that a monolayer of KCl on iron reduces the friction coefficient from its clean-surface value of ~2, to 0.27, while a layer of FeCl2 reduces it to ~0.08. The friction coefficient increases once again as the film becomes thicker and this effect can be modeled using Greenwood-Williamson theory. Systematically varying the nature of the film and the substrate allows the limiting friction coefficient of the monolayer to be related to the mechanical properties of both the films and the substrate. |
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Friction, Lubrication, and Adhesion in Micro- and Nano-Scale Devices
8:30 AM-12:00 PM, Tuesday, March 30, 2004 Marriott -- Orange County 5, Oral
Division of Colloid and Surface Chemistry |