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.

Keywords:

• Carbon/carbon composites
• Oxidation
• Solvothermal

This work was supported by the National Natural Science Foundation of China (grant nos. 51072108 and 51172134), Scientific Research Program Funded by Shaanxi Provincial Education Department of China (grant no. 2010JK444) and The Postgraduate Innovation Foundation of SUST.