In this study, carbon aerogel based lightweight composite ablators (CALCAs) with different densities and microstructures were prepared using the vacuum impregnation method. The mechanical strength and morphology of CALCAs were investigated. Ablation‐insulation performance of the samples was also evaluated by an oxyacetylene flame test with a constant heating rate of 2.5 MW/m². Moreover, the structural evolution during the ablation was studied and the ablation mechanism of CALCAs was proposed. The porous insulators showed good compressive strength (3.2–9 MPa) and low thermal conductivity (lower than 0.35 W/mK). Besides the tunable density, the low recession rate (as low as 0.117 mm/s), and good ablation‐insulation performance (175°C at 25 mm and 125 at 35 mm in‐depth), these lightweight porous heat shielding composites are promising candidates to use as the thermal protection systems for aerospace applications.

中文翻译：

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碳气凝胶基轻质隔热复合材料的隔热性能，微结构和力学性能

在这项研究中，使用真空浸渍方法制备了具有不同密度和微观结构的碳气凝胶基轻质复合消融器（CALCA）。研究了CALCA的机械强度和形态。还通过氧乙炔火焰测试（恒定加​​热速率为2.5 MW / m ^2）评估了样品的消融绝缘性能。此外，研究了烧蚀过程中的结构演变，并提出了CALCAs的烧蚀机理。多孔绝缘子表现出良好的抗压强度（3.2-9 MPa）和低导热率（低于0.35 W / mK）。除了可调节的密度，低的回缩率（低至0.117 mm / s）和良好的消融绝缘性能（25 mm时175°C，35 mm时深度125），这些轻质多孔隔热复合材料还是有希望的用作航空航天应用的热保护系统的候选人。