Micro- and macro-tribological properties of SiC ceramics in sliding contact

Surface properties of single-crystalline and polycrystalline silicon carbid e (SiC) specimens were measured using atomic force/friction force microscop y, Auger electron spectroscopy and nano-indentation techniques. Running-in behavior during sliding tests in vacuum was studied on self-mated SiC pairs as a function of surface quality produced by machining. Tribological mecha nisms were analyzed in short-time tests using a high-resolution micro-tribo meter and then were related to results obtained from macro-tribological tes ts in humid air and in the presence of distilled water. Information on the structure, chemical composition and properties of SiC surfaces resulting fr om measurements on the nanoscale can be very useful for explaining tribolog ical performance under far different operating conditions such as in vacuum or air, with contact areas ranging from diameters of a few nanometers to o ne millimeter and initial applied contact pressure from about 1 MPa to 3 GP a. Friction and wear mechanisms are discussed as functions of surface compo sition and roughness, vacuum and humidity of air. (C) 2001 Elsevier Science B.V. All rights reserved.