Biomorphic C/SiC composites were prepared by infiltrating liquid Si into a carbon preform made from medium-density fiberboard. The effects of residual Si on the ablation properties of the composites were investigated using an oxy-kerosene hypersonic torch. The results revealed that reducing the amount of residual Si plays an important role in increasing the ablation and thermal shock resistances. High residual Si resulted in thermal-shock cracking due to the high thermal expansion coefficient and volume change during melting. The composite infiltrated with 30 wt.% Si showed 0.9 × 10–4 g/cm2∙s of the ablation rate and no thermal-shock cracking after three successive ablation tests due to the formation of a thin SiO2 layer. Our findings suggest that biomorphic C/SiC composites with minimal residual Si may be suitable as reusable thermal protectors for reentry vehicles.

中文翻译：

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残余Si对可重复使用热保护系统生物形态C/SiC复合材料烧蚀性能的影响

通过将液态硅渗透到由中密度纤维板制成的碳预制件中制备生物形态 C/SiC 复合材料。使用氧煤油高超声速炬研究了残余硅对复合材料烧蚀性能的影响。结果表明，减少残余硅的量在增加抗烧蚀和抗热震性方面起着重要作用。由于高热膨胀系数和熔化过程中的体积变化，高残余硅导致热冲击开裂。渗入 30 wt.% Si 的复合材料显示出 0.9 × 10–4 g/cm2∙s 的烧蚀速率，并且在三个连续烧蚀测试后由于形成薄的 SiO2 层而没有热冲击开裂。