HIGH-TEMPERATURE LUBRICATION OF VARIOUS CERAMICS AND METAL-ALLOYS VIADIRECTED HYDROCARBON FEED GASES

High temperature lubrication via the in situ deposition of lubricous c arbon surface films from the pyrolytic decomposition of hydrocarbon fe ed gas has been confirmed on a variety of self-mated ceramic and metal alloy sliding contacts. Pin-on-disk tests were performed at 520 degre es C in an atmosphere purged with nitrogen at 3 l/min, with a directed acetylene admixture supplied at 0.2 l/min, and compared to tests in n itrogen alone or air. Friction coefficients of Less than mu approximat e to 0.08 were recorded for all metal alloys tested-AISI M50, 52100, 4 40C and 1018 steel, as well as K-Monel (500) and Hastalloy C276. Frict ion coefficients of less than mu approximate to 0.10 were found for al umina, silicon nitride, tungsten carbide, and zirconia. Only soda lime glass showed no friction coefficient reduction upon acetylene admixtu re. In general, acetylene admixture also significantly reduced wear vo lume, with wear reductions of multiple orders of magnitude in many ins tances. (C) 1998 Elsevier Science S.A.