The reaction of metal carbides with polyol esters found in aerospace lubricants and phosphate esters commonly used as additives was investigated. Carbides were of particular interest since modern materials under consideration at high temperature bearings have surfaces that are primarily metal carbides. Vanadium and chromium carbide were found to react with the ester and phosphate ester by a transesterification reaction, producing an alkyl phosphate which is less stable than the aromatic phosphate esters. In the process, the metal carbide is converted to the metal phosphate and metal polyphosphate, evidenced by the infrared and Raman spectra of the solid residue and presence of a large amount of phosphorus found on the surface of the material. Arguments for the mechanism of this reaction are based on the examination of the reaction vanadium carbide and chromium carbide with an extensive series of model compounds, prepared for this study. The model compounds allow several intermediates to be identified and the reaction pathway to be determined.