Gradient fiber-reinforced aerogel composites using surface ceramicizable-resin densification with outstanding ablation resistance for high-temperature thermal protection

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.