Oxidation behaviour of matrix modified carbon/carbon composites by novel solvothermal process

Abstract

In order to investigate the oxidation behaviour and oxidative mechanism of the as modified carbon/carbon (C/C) composites at the temperature range of 600–800°C, C/C composites were modified by a novel solvothermal process using tributyl borate, absolute alcohol, acetic acid and B2O3 powders as raw materials. The phase compositions and microstructures of the modified C/C composites were characterised by X-ray diffraction, laser Raman spectra, SEM and energy dispersive spectroscopy analyses. Results show that after modification, the surface and internal defects of C/C composites are covered and occupied by a glassy B2O3 layer and B2O3 crystallites; the oxidation resistance of C/C composites is effectively improved. After oxidation at 650°C for 22 h, the mass loss of the composites is only 3·34%. In comparison with the non-modified composites, the oxidative mechanism of modified composites is changed, and the corresponding oxidation activation energy of composites is obviously enhanced.