Oxidation behavior of 3D C/SiC composites in two oxidizing environments

The oxidative durability of a SiC-sealed 3D C/SiC composites was investigated at 1250°C for exposure duration of up to 9 h in the high-velocity flame of a burner rig. The testing results showed that the mass loss of the composites was related to the pores and the microcracks in the material, and the occurrence of a high-porosity zone in SiC matrix played a key role in understanding the effect of environment on mass loss of the composites. Different oxidation behaviors of the SiC-sealed 3D C/SiC composites in combustion environment and in dry air were also compared. The mechanical properties of the C/SiC composites exposed in combustion gas were shown to decrease less apparently than in dry air, which mainly resulted from the low partial pressure of oxygen in combustion atmosphere.