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 degreesC 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. (C) 2001 Elsevier Science Ltd. All rights reserved.