High Strength, Oxidation Resistant Carbon/Carbon Composites

"Higher strength carbon/carbon (C/C) composites are required if such components are to replace currently used titanium products in the aircraft industry. This Phase I STTR addresses this need with the development of C/C composites with a 3-D fiberarchitecture and a reinforced carbon matrix. The 3-D preform composites have demonstrated superior compressive and tensile strength in relationship to comparable 2-D and 3-D composites. The strength of the carbon matrix will be enhanced by reinforcingwith carbon nanotubes, which are theoretically the strongest known materials. Significant increases in strength have already been demonstrated for a commonly used carbon precursor with only 1 wt% nanotube addition.MER Corporation will perform the development effort to produce high strength C/C composites. ORNL will develop coatings for these composites using their new high-density-infrared, transient-liquid coating process which produces coatings with densities upto 98-100% of theoretical with coating thickness of 10¿m to 2mm. The versatility of this technique will be utilized to produce coatings of varying thickness, followed by oxidation studies to demonstrate the ability of the coating to protect compositesfor thousands of hours. The program will culminate in the generation of composites with specific mechanical properties which will be selected for identified applications. Higher strength, oxidation resistant C/C composites will be enabling for many applications including airframes, engine components, aircraft brakes, turbine engine flaps, rocket nozzles, re-entry vehicle nose tips, etc."