Influence of hydrothermal treatment temperature on oxidation modification of C/C composites with aluminum phosphates solution by a microwave hydrothermal process

Abstract Carbon/carbon (C/C) composites were modified with an aluminum phosphates solution by a novel microwave hydrothermal (MH) process in order to improve their low temperature oxidation resistance. Results show that a H3PO4 or HPO3 continuous molten layer with some regular, white cubic Al(PO3)3 crystallites are obtained on the surface of the modified composites. The anti-oxidation property of the composites after modification improves with the increase of the MH temperature from 393 to 473 K. The oxidation rate is almost constant after oxidation at 873 K for 6 h. The formation of annular structure of Al(PO3)3 is helpful to improve the oxidation resistance of the composites.