| 摘 要： | C/C–HfC–SiC composites prepared by precursor infiltration and pyrolysis process were ablated by oxyacetylene torch under two different flame conditions.The ablation performance of the composites was investigated in the heat flux of 2.38 MW/m~2(HF-L) and 4.18 MW/m~2(HF-H) for 60 s.The mechanical denudation in 4.18 MW/m~2(HF-H) was higher than that in 2.38 MW/m~2(HF-L),while the results indicated that the composites had a similar and good ablation property under two different flame conditions.C/C–HfC–SiC composites can adapt the heat flux from 2.38 MW/m~2 to 4.18 MW/m~2.The HfO_2 was not melted completely in the heat flux of 2.38 MW/m~2(HF-L).So,both HfO_2 and SiO_2 layers acted as an effective barrier to the transfer of heat and oxidative gases into the underlying carbon substrate.SiO_2 was severely consumed in 4.18 MW/m~2(HF-H),where the HfO_2 molten layer played a more important role in protecting the inner composite.
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