SiC coatings on the surface of the three dimensional needled carbon/ carbon and silicon carbide (C/ C
-SiC) composites were prepared by chemical vapor deposition (CVD) at 1 050益. The coatings are prepared by two
kinds of experimental conditions which the flow ratio of diluting gas to carrier gas are 4 颐1 and 2 颐1. The crystalline
structure and the surface and cross section micromorphologies of the coatings are analyzed by X-ray diffraction and
scanning electronic microscopy. The oxidation and ablation performance are compared between uncoated and coated
C/ C-SiC composites. The results show that the deposited coatings mainly consist of 茁-SiC. The surface of coating
prepared with reducing the flow of diluting gas is smooth and dense,and also strongly bonded with the substrate. As to
the coated C/ C-SiC composites, the linear ablation rate is reduced by 34% and 50%, and the mass ablation rate re鄄
duced by 70% and 75%, compared to that of the uncoated C/ C-SiC composites prepared with two kinds of flow rati鄄
os, respectively, and the coatings show excellent antioxidation and anti鄄ablative performances.