Carbon fiber needling preform reinforced C/ C-SiC composites and C/ C-SiC-ZrB2 composites were
prepared by liquor dipping process. The mechanical, thermal and ablation properties of the composites were investigated
and compared. The results show that the flexural strength,compress strength and shear strength of the C/ C-SiCZrB2
composite are 199 MPa, 274 MPa and 19. 3 MPa respectively. These mechanical properties of the C/ C-SiCZrB2
composite are all lower than the counterpart properties of C/ C-SiC composite. Compared with C/ C-SiC composite,
thermal conductivity of the C/ C-SiC-ZrB2 is greatly higher and the linear expansion coefficient of the C/ C-SiCZrB2
composite is slightly lower. The ablation behavior of them is studied by arc wind tunnel test at a temperature of 2
500 K for 600 s. The C/ C-SiC-ZrB2 composite has an average mass ablation rate of 0. 4×10-4 g/ s and has excellent
properties of oxidation resistance and ablation resistance.