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

Abstract

In order to protect carbon/carbon (C/C) composites from oxidation at 1700 • C, a MoSi 2 -SiC-Si/MoSi 2 coating was prepared on the surface of these composites by a simple and effective method. The MoSi 2 -SiC-Si inner layer was obtained by pack cementation, and the MoSi 2 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 • C in air. The excellent anti-oxidation ability of this coating is attributed to its dense structure and the formation of the SiO 2 film on the coating surface during oxidation. Surf. Rev. Lett. 2009.16:437-440. Downloaded from www.worldscientific.com by MCGILL UNIVERSITY on 03/16/15. For personal use only.

Si–Mo–Cr coating for C/SiC coated carbon/carbon composites against oxidation

“…5 Oxidation resistant coatings, especially multilayer coatings, are considered as the best choice to protect C/C composites from oxidation at high temperatures. 6,7 Up to now, many multilayer coatings such as SiC/SiC-Si-ZrSiO 4 coating, 8 SiC/(Mo, W)Si 2 coating 9 and SiC/borosilicate glass coating 10 have been achieved by several researchers with the aim of improving the oxidation resistance of C/C composites above 1000uC. Among these multilayer coatings, SiC is considered as one of the best bonding layers between C/C composites and the outer layer because of its good physical and chemical adaptability of coating to matrix and bonding layer to outer layer.…”

“…These inhibitive additives decrease the oxidation rate by only a few orders of magnitude, so it is only useful for a short period of time and at temperature below 1000°C 5. Oxidation resistant coatings, especially multilayer coatings, are considered as the best choice to protect C/C composites from oxidation at high temperatures 6,7 Up to now, many multilayer coatings such as SiC/SiC–Si–ZrSiO 4 coating,8 SiC/(Mo, W)Si 2 coating9 and SiC/borosilicate glass coating10 have been achieved by several researchers with the aim of improving the oxidation resistance of C/C composites above 1000°C.…”