Oxidation Behavior and Microstructure Evolution of Nuclear-Grade C/C Composites Oxidized in Air and He

Carbon-carbon (C/C) composites have been widely used for high-temperature structural applications because they possess excellent mechanical properties such as high specific strength and thermal shock resistance. In the nuclear industry, the composites have been also considered for plasma facing materials in fusion reactors and high-temperature structural parts in gas cooled reactors. In the high-temperature gas cooled reactor, the composites are being considered for the application of various high-temperature structural parts such as control rod components, core restraint belts, tie rods, upper plenum shroud, hot duct insulation cover sheets, and floor blocks. However, the carbon based materials are susceptible to oxidation at temperatures above 400 .deg. C. Therefore, the oxidation behavior and property degradation at high temperature under impure He or in air in case of accidental air ingress should be evaluated before the deployment of composites. In this study, the oxidation behavior and microstructure change of nuclear-grade C/C composites, Toyo Tanso CX-270G and SGL Sigrabond 1501YR, were evaluated after oxidation at various temperatures. The oxidation experiments were performed in range of 500 to 1200 .deg. C under air and He atmosphere