Processing and measurement of basic properties of SiC and cordierite coatings of carbon/carbon composite

SiC and four cordierite materials, which are compounds of MgOAl 2O 3SiO 2 mixed with B 2O 3 and GeO 2, were selected in this work as coatings on a three-dimensional carbon/carbon composite (3D C/C). A CVD carbon film, which was treated as a bond coat, was first applied to homogenize the surface of the C/C, then an SiC coating was deposited. The SiC was prepared by reaction-sintering an Si powder layer with the precoated CVD carbon film. The sintering of cordierite materials and the reactions between the cordierite and SiC coatings were investigated. The processing parameters of CVD carbon, SiC and cordierite coatings were optimized for the formation of SiC and the densification and crystallization of cordierites. The dual coating, SiC/225 cordierite, was selected to coat on the C/C and exhibited good protection against oxidation. The combination of coating layers successfully prevented oxygen from reaction with the C/C substrate.