Advised by Andrew J. Gellman
Vapor phase lubrication (VPL) has been proposed as a method for lubricating high temperature engine components. During VPL, lubricants are continuously delivered in the vapor phase to high temperature engine parts and react to deposit a thin, solid, lubricating film which protects the engine surfaces exposed to sliding wear. Previous research has studied tricresylphosphate (TCP) [(CH3-C6H4O)3P=O], one of the most common vapor phase lubricants. TCP decomposes on metal surfaces to form polyphosphate films containing carbon and phosphorous elements. This carbon/phosphorous film is known to provide effective lubrication. The surfaces of ceramics such as SiC are unreactive for the decomposition of TCP and thus not amenable to vapor phase lubrication. As a means of activating the SiC surface, we have used chemical vapor deposition of Fe from Fe(CO)5. The objective of this research is to understand the differences in the surface chemistry of TCP on SiC surfaces and Fe-coated SiC surfaces. The activation of SiC surfaces by chemical vapor deposition of Fe was studied using Auger electron spectroscopy (AES) to monitor the deposition of carbon and phosphorous on SiC surfaces during exposure to TCP. The results of this research show that TCP decomposes more readily on Fe-coated SiC surfaces than on SiC surfaces and that increasing the coverage of Fe increases the carbon and phosphorous deposition rate. Oxidation of the Fe further accelerates TCP decomposition. This work provides a proof-of-concept demonstration of the potential for vapor phase lubrication of ceramics.