The friction and wear of a 20 via silicon carbide whisker-silicon nitride matrix composite was measured at room temperature in both lubricated and unlubricated sliding. A pin-on-disk test configuration was used in which the pin member was a 9.53 mm diameter sphere. Silicon carbide and silicon nitride spheres were tested against the composite in both unidirectional and reciprocating sliding. The range of experimental parameters included normal forces from 1 to 45 N, velocities of 0.1 and 0.3 m/s and test durations of five minutes to three hours. The lubricant used in the room temperature tests was a commercial synthetic, fully formulated engine oil (5W30). In unlubricated sliding, silicon nitride produced more severe wear of the composite than did silicon carbide. In lubricated sliding, very little wear occurs in either sliding pair at even the longest test exposure. The data are presented in “wear space” co-ordinates and this form of presentation is compared to other wear mechanism map concepts presently in use.Presented as a Society of Tribologists and Lubrication Engineers paper at the ASME/STLE Tribology Conference in Toronto, Ontario, Canada, October 8–10, 1990