Si-Al-Ir Oxidation Resistant Coating for Carbon/Carbon Composites by Slurry Dipping

A Si-Al-Ir oxidation resistant coating was prepared for SiC coated carbon/carbon composites by slurry dipping.The phase composition, microstructure and oxidation resistance of the as-prepared Si-Al-Ir coating were studied by XRD (X-ray diffraction), SEM (scanning electron microscopy), and isothermal oxidation test at 1773 K in air, respectively.The surface of the as-prepared Si-Al-Ir coating was dense and the thickness was approximately 100/μm.Its anti-oxidation property was superior to that of the inner SiC coating.The weight loss of SiC/Si-Al-Ir coated carbon/carbon composites was less than 5 wt.pct after oxidation at 1773 K in air for 79 h.The local oxidation defects in the coating may result in the failure of the SiC/Si-Al-Ir coating.