Effect of content of boron oxide on structure and anti-oxidation property of SiC coating on C/C composites

Taking boron oxides as additives, SiC anti-oxidation coatings were prepared on the surface of carbon/carbon composites in order to improve the compatibility between the coating and the carbon/carbon composite. The morphologies, phases and oxidation property of the four kinds of SiC coatings with the molar content of boron oxides of 0%, 2%, 5% and 10% were studied. The analysis results of SEM, XRD and the oxidation experiment reveal that the boron oxides facilitate effectively the infiltration of coating material into the carbon/carbon composites. With the increase of the quantity of boron oxides, the thickness of coating grow thicker. The C/C composite with 2% boron oxides behaves a 0.32% weight-gain after oxidation at 1500°C for 5 h.