Exceptionally ablation-resistant lightweight ceramic fiber-reinforced Si-PR aerogel composites based on a ceramic biphasic system

The pronounced oxidative degradation and substantial ablation recession of traditional lightweight ablative materials in low-altitude, medium-to-high temperature service environments highlight a critical deficiency, underscoring the urgent need for novel, high-performance ablation-resistant thermal protection systems. Herein, we utilize in-situ chemical grafting principles combined with sol-gel processes to develop a ceramic fiber matrix material system. The bending strength of MFC reached 7.7 MPa; the compressive strengths in Z direction and XY direction were 4.0 MPa and 9.03 MPa, respectively, due to the confining effect of the SiPRA. The thermal conductivity of MFC was 0.031–0.051 W/(m·K). More importantly, the increased fiber content reduced the effective heat release of MFC, demonstrating outstanding ablation-resistant thermal insulation properties. After repeated testing (1300°C-1800 s/cycle), the backside temperature was 188.2–218.9 °C, with zero ablation retreat; under short-term aerodynamic conditions at 1750 °C, the backside surface temperature ranges from 122.6 to 134.3 °C, with a linear ablation rate as low as 0.021 mm/s. MFC is an ideal choice for thermal protection systems in hypersonic spacecraft, and near-space vehicles.