Long-term oxidation behavior of carbon/carbon composites with a SiC/B4C-B2O3-SiO2-Al2O3 coating at low and medium temperatures

摘要

To achieve the long-term oxidation protection of carbon/carbon composites at low and medium temperatures, a SiC/B4C-B2O3-SiO2-Al2O3 coating was applied on the composites. The coating exhibits a dual-layer structure with a dense SiC inner layer and B4C-B2O3-SiO2-Al2O3 multi-phase outer layer. The effects of Al2O3 contents and oxidation temperatures on the oxidation behavior of the coated C/C were investigated. The results shows that the coating with 7.7 wt.% Al2O3 performs excellent self-healing ability and can protect the C/C composites with weight losses of less than 1% for 250 h at 800 degrees C and for 90h at 900 degrees C and 1000 degrees C. (C) 2015 Elsevier Ltd. All rights reserved.