The unlubricated sliding wear of an alumina-silicon carbide whisker composite (20 volume percent whiskers) has been investigated in air at 20, 400, and 800°C. Mild wear was observed in room-temperature pin-on-disc tests at sliding velocities of 0.1 and 0.5 m/s for contact stresses up to 75 MPa. At a velocity of 0.5 m/s and a contact stress of 50 MPa. a transition to severe wear occurs after 6 to 8 km of sliding. Severe wear begins within the first kilometer of sliding at 400°C, while at 800°C mild wear results at stresses as great as 150 MPa. The severe wear debris produced at 400°C was examined by analytical electron microscopy (AEM) techniques and found to consist primarily of particles of Al2O3and SiC in the 10- to 50-nm-size range. The mild wear process at 800°C did not produce any significant debris, but did show evidence of surface chemical reaction. Auger analysis of the surface showed the wear track to be covered by a mixture of aluminum and silicon oxides and the exposed silicon carbide whisker surfaces to be oxidized.Presented as a Society of Tribologists and Lubrication Engineers paper at the ASME/STLE Tribology Conference in Baltimore, Maryland, October 16–19, 1988