Fiber-reinforced aerogel composites (FACs) can be applied to the thermal protection system of aerospace vehicles, but the ablative recession is unsatisfactory. We report a novel quartz felt-reinforced phenolic aerogel composite with surface densification (QFPS). The composite with gradients provides enhanced thermal protection under high-temperature and repeated ablation. QFPS was fabricated through surface ceramicizable-resin impregnating and internal phenolic resin aerogel impregnating. QFPS showed desirable thermal and mechanical properties. The internal thermal conductivity was below 0.03 W/(m⋅K), and the tensile, bending, and full-volume rebound compressive strengths were 11.22, 16.25, and 0.48 MPa. Oxy-acetylene ablation test showed a linear setback of 0.003 mm/s, a weight loss of 0.016 g/s for the composite, with a backside temperature below 70 °C. The 10-times repeated butane ablation test showed a slight recession with linear setback and weight loss of 0.30 μm/s and 5.70 mg/s. This composite presents huge application prospects in aerodynamic heating environments.

纤维增强气凝胶复合材料（FACs）可应用于航空航天器的热防护系统，但烧蚀衰退不能令人满意。我们报告了一种具有表面致密化 (QFPS) 的新型石英毡增强酚醛气凝胶复合材料。具有梯度的复合材料在高温和重复烧蚀下提供了增强的热保护。QFPS 是通过表面可陶瓷化树脂浸渍和内部酚醛树脂气凝胶浸渍制成的。QFPS 显示出理想的热和机械性能。内部热导率低于0.03 W/(m·K)，拉伸、弯曲和全体积回弹抗压强度分别为11.22、16.25和0.48 MPa。氧乙炔烧蚀试验表明复合材料的线性回退为 0.003 mm/s，重量损失为 0.016 g/s，背面温度低于 70 °C。10 次重复丁烷消融试验显示轻微衰退，线性挫折和重量损失分别为 0.30 μm/s 和 5.70 mg/s。这种复合材料在气动加热环境中具有巨大的应用前景。