A MoSi2-SiC-Si/MoSi2 COATING TO PROTECT CARBON/CARBON COMPOSITES AGAINST OXIDATION AT 1700°C

In order to protect carbon/carbon (C/C) composites from oxidation at 1700 degrees C, a MoSi2-SiC-Si/MoSi2 coating was prepared on the surface of these composites by a simple and effective method. The MoSi2-SiC-Si inner layer was obtained by pack cementation, and the MoSi2 outer layer was prepared by slurry coating using silicon-sol as the caking agent. The microstructures of the as-prepared coating were examined by X-ray diffraction and scanning electron microscope. Oxidation test shows that, the as-received coating can protect C/C composites from oxidation for more than 107 h at 1700 degrees C in air. The excellent anti-oxidation ability of this coating is attributed to its dense structure and the formation of the SiO2 film on the coating surface during oxidation.