Highly Compressible, Wave-Transparent, and Heat-Insulating SiO2 Microfiber/Boron Nitride Nanosheet Composite Aerogels: Implications for Aircraft Radome Materials

As a radome, an essential component for maintaining aircraft communication and navigation systems, the interlayer thermal insulation materials of radome require to possess specific mechanical strength, exceptional thermal insulation, and electromagnetic wave transmission capabilities to ensure stable signal transmission. In this study, we fabricated elastic silica aerogels by direct electrospinning, and the composite aerogels were prepared by combining silica aerogels with BN nanosheets by the freeze-drying method. Composite aerogels with an innovative structure exhibit superior thermal insulation and wave permeability. The layer-by-layer and the locally closed-pore structure significantly enhances the mechanical properties and thermal insulation efficiency in high-temperature environments. Specifically, the composite aerogels are lightweight (40 mg cm–3) and exhibit favorable mechanical properties, low thermal conductivity (0.0238 W m–1 K–1), and excellent dielectric properties (ε′ = 2.75–2.83, tan δ < 6.25 × 10–3). The results indicate that electromagnetic waves can be stably transmitted through the composite aerogels. This research offers valuable perspectives and guidance for advancing and refining thermal insulation and wave-transparent aircraft radome materials.