SiC Nanowire–Granule Aerogels with Zero- and One-Dimensional Configuration via Precursor Infiltration–Gelation and Pyrolysis

The inherent brittleness of conventional nanoparticle-based silicon carbide (SiC) aerogels severely limits their practical application in extreme environments requiring thermal insulation. Herein, we report a hierarchically configured zero- and one-dimensional (0D-1D) SiC nanowire–granule (SiC-NG) aerogel synthesized via a precursor infiltration–gelation and pyrolysis strategy. By infiltrating bridged polysilsesquioxane (BPSi) precursor solutions into pre-synthesized BPSi aerogel scaffolds, in situ growth of 1D SiC nanowires is achieved within the 0D granular skeleton, constructing an interpenetrating “point–line” network architecture. The resulting SiC-NG aerogel exhibits a low density of 0.121 g cm−3 and a high porosity of 87.02%. This hierarchical configuration substantially enhances mechanical robustness, delivering a compressive strength of 0.251 MPa and elastic modulus of 1.619 MPa, outperforming conventional granular SiC aerogels. Moreover, the aerogel demonstrates good thermal insulation performance, maintaining a cold-side temperature of only 300 °C after 5 min of direct exposure to a 1300 °C butane flame. This work establishes a versatile strategy for designing mechanically reinforced, hierarchically structured ceramic aerogels for advanced thermal protection under extreme environments.