Two鄄dimensional(2D) C/ SiC composites were fabricated by chemical vapor infiltration(CVI) com鄄
bined with polymer impregnation and pyrolysis( PIP) using polyaluminocarbosilane( PACS) as precursor. Properties
including microstructure,mechanical properties and thermal expansion of the composites were investigated. The abla鄄
tion properties of C/ SiC composites were investigated by the oxyacetylene torch flame. The results show that adding a
small amount of Al has little effect on microstructure, coefficient of thermal expansion( CTE),flexural strength and
toughness of composites. However,the addition of a small amount of Al into C/ SiC composite effectively enhances its
ablation resistance. SiC reacts with oxygen to form a silica film,which causes Al melt into silica. Al doping can not on鄄
ly increase the viscosity of silica,but also reduce the activity of silica. Compare with the no addition of Al into C/ SiC
composites,the linear ablation rate decreased by 26%.