SiC/SiC复合材料在高温空气中的氧化行为

As one of important candidates for advanced aerocraft engine hot components, SiC/SiC composites would undergo oxidative and corrosive damage when subjected to high temperature combustion environment. Oxidation behavior of SiC/SiC composites at 1100-1300 ℃ in air was investigated in the present work, to clarify the oxidative and corrosive behavior of the composites. The oxidation kinetics curves were obtained. The morphology and composition evolution of the oxidized materials were analyzed by SEM, XPS and XRD. The results show that the oxidation kinetics of SiC/SiC composites at 1100-1300 ℃ follow the parabolic law and the oxides on the surface mainly consist of silica. Slight oxidation occurs at 1100 ℃. The oxidation rate increases with increasing temperature. The oxidation process is mainly concentrated in the BN interface phase and the pores of the matrix. The bending strength of the composite decreases with the oxidation extent.