Tensile behaviour of SiC coated carbon/carbon composites after exposure to A CH₄, combustion gas

Tensile behaviour and microstructure of a SiC coated C/C composite were investigated after exposure to a CH₄ combustion gas with flame temperatures of 1300 °C and 1800 °C. The tensile strength of the composite was respectively reduced to 61.9% and 77.7% of their original values. Superficial oxidation of the C/C substrate was responsible for strength reduction. Multi-tube-walled structure of the C/C substrate was observed after oxidation, which was caused by the difference in reactivity between the carbon fibre and the matrix. Silica spheres were observed to adhere to the C/C substrate beneath the coating, which was caused by active oxidation of SiC.