This study examines the wear resistance of Si3N4-TiC composites subjected to pin-on-diamond disk abrasion and gas-jet Al2O3-particle erosion. The contact damage and wear resistance have been related to the mechanical properties and microstructure of the composites, which differ by their volume fraction and grain size of TiC particulates. Findings suggest that predictions of ceramic composite wear resistance based solely upon hardness and fracture toughness, in the absence of additional information regarding microstructure, may be inaccurate. Wear resistance of Si3N4-TiC composites was found to be more reliably defined by including dispersoid separation, a function of its size and volume fraction, into predictive equations.Presented at the 45th Annual Meeting in Denver, Colorado May 7–10, 1990