Antioxidation of carbon-carbon composites by SiC concentration gradient and zircon overcoating Original Research Article

After the formation of a concentration gradient of SiC within a carbon-carbon composite, a zircon (ZrSiO4) thin film was coated on the surface. Oxidation-resistance tests of the treated CC composites were then carried out. A concentration gradient of SiC was produced by heating the CC composite in silicon powder at 1450 °C for 3 hours. The concentration of SiC along the direction of the carbon fiber sheets decreased rapidly up to 0.25 mm and, in the perpendicular direction, decreased steeply in a range of 0.4–0.6 mm. By the overcoating of zircon with the thickness of 1.5 μm, a remarkable improvement in the oxidation resistance was observed; the weight loss was almost negligible at 1000 °C and one hundredth of the original composite at 1400 °C.