Ceramic aerogels are promising lightweight and high-efficient thermal insulators for applications in buildings, industry, and aerospace vehicles but are usually limited by their brittleness and structural collapse at high temperatures. In recent years, fabricating nanostructure-based ultralight materials has been proved to be an effective way to realize the resilience of ceramic aerogels. However, the randomly distributed macroscale pores in these architectures usually lead to low stiffness and reduced thermal insulation performance. Here, to overcome these obstacles, a SiC@SiO₂ nanowire aerogel with a nanowire-assembled anisotropic and hierarchical microstructure was prepared by using directional freeze casting and subsequent heat treatment. The aerogel exhibits an ultralow thermal conductivity of ~14 mW/m·K, an exceptional high stiffness (a specific modulus of ~24.7 kN·m/kg), and excellent thermal and chemical stabilities even under heating at 1200°C by a butane blow torch, which makes it an ideal thermally superinsulating material for applications under extreme conditions.

陶瓷气凝胶是有望用于建筑，工业和航空航天器的轻质，高效的绝热材料，但通常受到其在高温下的脆性和结构破坏的限制。近年来，已证明制造基于纳米结构的超轻材料是实现陶瓷气凝胶弹性的有效方法。然而，在这些结构中随机分布的宏观孔隙通常导致低刚度和降低的隔热性能。在这里，为了克服这些障碍，采用了SiC @ SiO ₂通过使用定向冷冻浇铸和随后的热处理来制备具有纳米线组装的各向异性和分级微观结构的纳米线气凝胶。气凝胶的超低导热系数约为14 mW / m·K，具有很高的刚度（比模量约为24.7 kN·m / kg），即使在1200°C的丁烷加热下也具有出色的热稳定性和化学稳定性。吹焊枪，使其成为极端条件下的理想绝热材料。