Tribofilm Formation and Run-In Behavior in Ultra-Low-Wearing Polytetrafluoroethylene (PTFE) and Alumina Nanocomposites |
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Authors: | Brandon A Krick Jeffrey J Ewin Edward J McCumiskey |
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Affiliation: | 1. Department of Mechanical Engineering and Mechanics, Lehigh University, Bethlehem, Pennsylvania 18015;2. Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, Florida 32611 |
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Abstract: | Polytetrafluoroethylene (PTFE) and alumina nanocomposites have been of great interest to the tribological community due to the significant reduction in wear imparted by filling PTFE with low weight percentages of alumina nanofillers. The mechanisms of these three order, four order, and sometimes five order of magnitude reductions in wear have been commonly explored through evaluation of a transfer film. The present article evaluates the tribofilm formed on the wear surface of the polymer. PTFE composites with 2, 5, and 8 wt% alumina fillers were tested to evaluate wear of the polymer and how it is affected by the tribofilms formed on the wear surface of the polymer. Furthermore, the link between a transient “run-in” wear period and the formation of that tribofilm is observed and discussed. Nanomechanical measurements of the tribofilm reveal significant alterations in the mechanical properties of the surface films formed during sliding. |
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Keywords: | Polytetrafluoroethylene PTFE Alumina Nanocomposite Tribofilm Running Film Wear Tribochemistry |
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