Document Type

Report

Publication Date

5-2006

Publication Title

NASA/TM—2006-214060

Abstract

One of the major problems preventing the operation of advanced gas turbine engines at higher temperatures is the inability of currently used liquid lubricants to survive at these higher temperatures under friction and wear conditions. Current state-of-the-art organic liquid lubricants rapidly degrade at temperatures above 300 °C; hence some other form of lubrication is necessary. Vapor-phase lubrication is a promising new technology for high-temperature lubrication. This lubrication method employs a liquid phosphate ester that is vaporized and delivered to bearings or gears; the vapor reacts with the metal surfaces, generating a solid lubricious film that has proven very stable at high temperatures. In this study, solid lubricious films were grown on cast-iron foils in order to obtain reaction and diffusion rate data to help characterize the growth mechanism. A phenomenological mathematical model of the film deposition process was derived incorporating transport and kinetic parameters that were coupled to the experimental data. This phenomenological model can now be reliably used as a predictive and scale-up tool for future vapor-phase lubrication studies.

Comments

Financial and technical support from the National Aeronautics and Space Administration under grants NCC3–971(0220–0620–10–GATIC18) and NCC3–1095 (0220–0620–10–GATIC20) is gratefully acknowledged. Financial support and technical facilities from the Department of Chemical and Biomedical Engineering and support from the Established Full-Time Faculty Research Development (EFFRD) program at Cleveland State University were also essential in completing this research and are acknowledged.

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