Engineering Covalent Heterointerface Enables Superelastic Amorphous SiC Meta-Aerogels.

SiC is an exceptionally competitive material for porous ceramics owing to its excellent high-temperature mechanical stability. However, SiC porous ceramics suffer from serious structural damage and mechanical degradation under thermal shock due to the hard SiC microstructure and weak bonding networks. Here, we report a scalable interface-engineering protocol to reliably assemble flexible amorphous SiC nanofibers into lamellar cellular meta-aerogels by designing a covalent heterointerface. This approach allows the construction of a strong binding architecture within the resilient nanofiber skeleton network, thereby achieving structurally stable, mechanically robust, and durable SiC porous ceramics. The optimized amorphous SiC meta-aerogels (a-SiC MAs) exhibit the integrated properties of ultralight with a density of 4.84 mg cm -3 , temperature-invariant superelastic, fatigue-resistant at low 5% permanent deformation after 1000 cycles of compression, and ultralow thermal conductivity (19 mW m -1 K -1 ). These characteristics provide a-SiC MAs potential application value in the thermal protection field.