Comparison Of Morphology And Microstructure Of Ablation Centre Of C/sic Composites By Oxy-acetylene Torch At 2900 And 3550 ℃

摘要

High-temperature application above 1600℃ of C/SiC composites requires evaluation of the ablation properties. The C/SiC composites were prepared by low pressure chemical vapor infiltration using CH_3SiCl_3 as precursor. As-prepared C/SiC composites were ablated by oxy-acetylene flame with the temperature of 2900 and 3550 ℃. Above 3550 ℃, subliming of carbon fiber and silicon carbide matrix was the main ablation behaviour. At 2900 ℃, thermal decomposition and oxidation of SiC matrix were the main ablation behaviour. A carbon coating resulted from the pyrolysis of the acetylene prevented the C/SiC from oxidizing dramatically.