Carbon-carbon composites are an emerging class of composite materials having a unique combination of high-temperature properties and low densities. These properties are attractive for hot structure and thermal protection system applications in future aerospace vehicles. Aerospace service environments of particular interest are cyclic temperature, oxidizing environments to 3000°F. For carbon-carbon composites to serve as practical engineering materials in such challenging environments, their long-term mechanical and chemical stability is essential.
Many aspects of proposed service environments for these composites pose significant challenges to their satisfactory performance. Among these aspects are the oxidizing nature of the environments (including both high and low oxygen partial pressures), high temperatures, moisture, cyclic temperature service, and foreign-object impact. This paper presents results from materials performance evaluations which cover each of these parameters. The focus is on oxidation-resistant carbon-carbon composites intended specifically for multi-use aerospace applications. Results are presented for the carbon-carbon material currently in use on Space Shuttle and for newer, more advanced structural forms of these composites.