Oxidation behaviour of hydrothermal modified carbon/carbon composites

Carbon/carbon (C/C) composites were modified by a novel hydrothermal process using Al2O3 powers and phosphoric acid as raw materials. The oxidation behaviour of the hydrothermal modified C/C composite at the temperature range of 600–800°C was particularly investigated. The phase compositions and microstructures of the modified C/C composites were characterised by X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy analyses. Results show that after hydrothermal modification, the surface of the composites is covered by an Al(PO3)3 particle dotted P2O5 layer, and the layer effectively improves the oxidation resistance of C/C composites. After 10 h oxidation at 700°C, the mass loss of the composites is only 2·31%. In comparison with the non-modified composites, the oxidation activation energy of the hydrothermal modified C/C composites is obviously increased.