Low-cost Oxidation Resistant C-c Composites

Carbon-carbon (C-C) composites exhibit excellent mechanical, thermal and chemical properties. Their commercial applications are limited by high cost and poor oxidation protection. A low cost process was developed to fabricate C-C composites in one manufacturing step, which leads to substantial cost savings over conventional processing methods. This low cost manufacturing process has been combined with novel oxidation inhibition. Low cost boron, and/or silicon and other additives based liquid precursors are used during the prepregg step. A high temperature heat treatment yields C-C composites exhibiting 1.75-1.85 g/cm density. The molecular level inhibition employed in this processing results in excellent oxidation protection, that has demonstrated up to 2000 hours of isothermal oxidation at 600°C with zero mass loss. The inhibition formula applied on the molecular level results in a moisture insensitive oxidation protection scheme. The mechanical properties of inhibited C-C composites are on par with the uninhibited composites. Tensile strengths of 210 MPa and compressive strengths of 150 MPa are typical. Process-structure-property relationships for this low cost inhibited class of C-C composites will be presented.