Abstract: Thermal insulation materials with light weight, high mechanical strength, and efficient thermal insulation are essential for ensuring aerospace vehicle safety. However, the development of thermal insulation materials with low thermal conductivity and radiation suppression is highly in demand. In this study, the hexagonal SiOC precursors were prepared from the methyl-terminated side chain acryloxypropyl silicone oil via digital light processing and continuous liquid interface production, which can be pyrolyzed at 1000 °C to obtain SiOC ceramics with various porosities (80 %, 85 %, and 90 %). The hexagonal SiOC-85 % ceramics showed a compressive strength of 13.44 ± 1.52 MPa with a density of 0.63 g/cm³. The biomimetic honeycomb SiOC-85 % ceramics were constructed through assembly of the hexagonal SiOC-85 % precursor samples and SiOC precursor fiber membranes prepared by electrospinning, followed by pyrolysis. The honeycomb SiOC-85 %-1 ceramics (one layer) showed a specific strength of ∼2.02 × 10⁴ N m/kg and a low thermal conductivity of 0.11 ± 0.01 W/(m K) at room temperature. Moreover, the honeycomb SiOC-85 %-1 ceramics (one layer) and SiOC-85 %-2 ceramics (two layers) exposed to 800 °C for 20 min displayed very low back-side temperatures of ∼184 °C and 168 °C, respectively. The biomimetic multi-layer honeycomb architecture provides a novel strategy for advanced thermal insulation in aerospace applications.

Key words: Biomimetic, Light weight, Silicon oxycarbide, Thermal insulation