Influence of Matrix Modification on the Oxidation Resistance of SiC/SiC Composites

SiC/SiC composites were prepared by precursor infiltration and pyrolysis process combined with three matrix modification methods. The effect of matrix modification on the high temperature oxidation resistance of SiC/SiC composites was analyzed by morphology analysis and mechanical property test. The results showed that the flexural strength of the matrix-modified composites hardly decreases after 100h static oxidation at 1200℃. After 200h oxidation, the retention rates of flexural strength reached 80%. After 300h oxidation, the internal structure of the composites was not oxidized and the oxidation degree of the interface layer in the surface area decreases. The B element in the modified matrix was oxidized to form liquid phase to seal the surface of SiC coating, which delayed the oxidation process of SiC coating, preventing the oxidation medium from entering the interior of the compo-site and protects the fiber and interface layer, so that the long-term static oxidation resistance of SiC/SiC composites was improved significantly.