Carbon materials obtained from organometallic modification of pitch and its oxidation resistance properties Original Research Article

Although carbon fiber reinforced carbon matrix (C/C) composites are used in the aerospace and utility industries, carbon materials oxidize readily at temperatures above 425 °C. A variety of coatings have been used to protect C/C composites from oxidation. The thermal expansion mismatch creates microcracks that could result in catastrophic failure. To alleviate these difficulties, we have used the approach of modifying the carbon precursor molecule with organometallic functions, which results in uniform and nanosize mixing of antioxidants in the carbon matrix. Mesophase pitch, which is a carbon precursor, was grafted with silicon and aluminum preceramic functions by using organometallic chemistry to produce Compounds 1, 2, 3 and 4. These organometallic pitches produce Chars A, B, C and D upon carbonization. Char C exhibits oxidation resistance superior to that of commercial carbon fiber.