High-temperature oxidation behavior of C/C composites in wet oxygen: Experiment and first-principle calculations

The oxidation behaviors of carbon/carbon composites prepared by chemical vapor infiltration method in wet oxygen were investigated by experiments and first-principle calculations. The results showed that the graphite components in mixed structure were easily destroyed and transformed into amorphous carbon in wet oxygen, accelerating the weight loss of C/C composites. The reason was ascribed to that hydroxyl radicals promoted the surface and inward diffusion of O atoms by uneven distribution of charges and formation of an exothermic reaction. Besides, the H transfer as a feasible way could result in the gather of epoxy radicals, increasing the risk of cracking.