A dense ZrB 2 particles reinforced glass (ZrB 2 /SiO 2) coating was prepared on the SiC coated carbon/carbon composites by a facile sol-dipping approach. The prepared ZrB 2 /SiO 2 coating could protect the composites from being oxidized for 160 h at 1773 K with a weight loss of 6.9 mg/cm 2. The flexural strength retention ratio of the ZrB 2 /SiO 2 coated composites is 87% after oxidation for 160 h at 1773 K. The continuous SiO 2 glass layer embedded with the submicron ZrSiO 4 particles was formed during oxidation. This was helpful to lower the diffusion rate of oxygen and improve the stability of SiO 2 glass film, thus improving the oxidation resistance of the coated samples. After thermal cycles between 1773 K and room temperature for 15 times, penetrated cracks formed in the coating. The weight loss of the ZrB 2 /SiO 2 coated sample presented linear relationship, and the final weight loss per unit area was 6.35 mg/cm 2. The generation of the penetrative cracks and the debonded coating interface resulted in the failure of the ZrB 2 /SiO 2 coating.

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Carbon fiber reinforced carbon matrix containing ZrC (C/C-ZrC) composites were prepared by hydrothermal deposition combined with carbothermal reduction. The submicron ZrC particles (100~300 nm) were dispersed in the matrix. The stress-strain curves of the composites presented a typical pseudo-plastic fracture behavior. The mass and linear ablation rates of the composites were 3.7×10-3 g/s and 4.2×10-3 mm/s, respectively. The formation of ZrO 2 glass layer reduced erosion of the composites in the ablation center. The continuous C-ZrC-ZrO 2 skeleton layer generated from the oxidation of ZrC can protect the composites from erosion at the ablation brim region. The obtained C/C-ZrC composites present a promising potential as ablation resistance materials.

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