AVS 47th International Symposium
    Surface Science Tuesday Sessions
       Session SS-TuP

Paper SS-TuP4
Lubrication Mechanisms of Tricresylphosphate, TCP, on Cr and Fe Surfaces at Elevated Temperatures: An Atomic-Scale View

Tuesday, October 3, 2000, 5:30 pm, Room Exhibit Hall C & D

Session: Poster Session
Presenter: M. Abdelmaksoud, North Carolina State University
Authors: M. Abdelmaksoud, North Carolina State University
B. Borovsky, North Carolina State University
J. Krim, North Carolina State University
Correspondent: Click to Email
TCP is a high-temperature vapor-phase lubricant which is known for its demonstrated anti-wear properties for macroscopic systems. Although this lubricant has been the subject of much research for over 40 years, the atomic-scale details of its lubrication mechanisms are far from being satisfactorily understood. In this study, we evaporated Fe and Cr substrates in UHV conditions onto Quartz Crystal Microbalances, (QCM), and then monitored the uptake rates of TCP on these substrates at different temperatures. Using an in-situ Auger spectrometer, the samples' surface chemistries were investigated in parallel with uptake rates at the various temperatures. Graphitic carbon was found to be the dominant surface constituent. To understand the role of oxygen in the lubrication process, some samples have been exposed to oxygen before TCP deposition. Comparing deposition rates of pure and oxide surfaces and the corresponding Auger scans allowed determination of whether or not oxygen has an effective part in the lubrication of these two metals with TCP. Our results suggest that oxygen is not a factor in controlling TCP interaction with Fe. Overall, we observed TCP to diffuse more readily into Fe than Cr, supporting recent conclusion by N. Forster.@footnote 1@ on the diffusion mechanisms underlying the lubricants effectiveness. In addition, we observed the TCP to greatly inhibit the uptake of oxygen from the gas phase. @FootnoteText@ @footnote 1@ N. H. Forster, Triboblogy Transactions, Volume 42, P. 10-20, (1999).