2003 年 52 巻 9Appendix 号 p. 235-241
2D-C/C composite is one of the promising materials as a next-generation core material in gas-cooled reactors. Effect of air-oxidation on the thermal diffusivity of the 2D-C/C composite was investigated in this study. Tested composite consists of 6K plain-woven fabrics with PAN-based carbon fiber and graphite matrix. Final heat-treatment of around 3073K was applied to the composite. The C/C composite specimens for measurement of thermal diffusivity were oxidized from 1 to 11% weight loss in air at 823K. Oxidation loss of the composite preferentially occurred at matrix part near the fiber bundles, and then occurred at fiber bundles. This composite exhibited large anisotropy in thermal diffusivity, higher value for parallel to lamina direction and lower value for perpendicular, e. g. thermal diffusivity of 1.1cm2/s for parallel to lamina and 0.2cm2/s for perpendicular at room temperature. Thermal diffusivity at room temperature declined 10-20% for parallel to lamina direction and 5-9% for that of perpendicular within 11% weight loss by oxidation. Thermal diffusivity tended to decrease gradually as the increase of oxidation loss in parallel to lamina, however, it decreased in the beginning of oxidation pretty much and not so changed by further oxidation loss in perpendicular to lamina. The different behavior due to air-oxidation on the thermal diffusivity in two directions was discussed from the fiber and/or matrix texture changes due to air-oxidation. Change in thermal conductivity under oxidation condition was also estimated from the obtained thermal diffusivity.