Surface Films and Soluble Degradation Products Formed in a PFPAE Fluid and Their Implications to the Wear of Steel |
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Authors: | B. Çavdar J. Liang P. J. John |
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Affiliation: | 1. Borg-Warner Automotive, Advanced Technology Center , Lombard, Illinois, 60148;2. University of Dayton Research Institute , Dayton, Ohio, 45469 |
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Abstract: | The soluble degradation products were generated in a linear perfluoropolyalkylether (PFPAE) fluid in boundary lubrication. Perfluoropolyalkylether carboxylic acid species were found in the residual fluids from the sliding tests by vibration spectroscopy. Surface-bound organic and inorganic reaction products were identified by vibration microspectroscopy with a grazing angle objective attachment and X-ray photoelectron spectroscopy (XPS), respectively. Inorganic surface films were found to be composed primarily of FeF3. A monodentate perfluorocarboxylate surface species was found on the sliding surfaces in 50° and 100°C tests but not found in 150°C tests. The higher friction and wear in 150°C tests as compared to 50° and 100°C tests were attributed to the absence of the perfluorocarboxylate species over the sliding surfaces at high temperatures. |
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Keywords: | Boundary Lubrication Lubricant Degradation Synthetic Lubricants Surface Films Surface Analytical Techniques Wear |
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