Light-weight, wood-derived, biomorphic SiC ceramics by carbothermal reduction

Mimicking nature is an effective strategy for designing high performance materials. However, artificially constructing biomimetic materials with complex hierarchical structures remains a great challenge. Herein, a biomimetic, anisotropic, robust, thermoconductive, and high temperature-resistant porous SiC ceramic is reported to be used as a high temperature filter. The unidirectional pore channel structure of poplar wood is accurately inherited in biomorphic SiC ceramic by an in-situ carbothermal reduction reaction between wood-derived carbon precursors and SiO vapor generated from SiO particles. Due to the anisotropic architecture with vertically aligned and densely interconnected pore channels, the light-weight and high purity biomorphic SiC ceramic exhibits an excellent flexural strength of 41.63 MPa at ∼78.6% porosity, a high thermal conductivity of 10.50 W m−1 K−1 with ∼77.6% porosity, an anisotropic thermal conductivity factor of 5.79, and good thermal stability at ∼900 °C. Meanwhile, it demonstrates a high gas permeability (k1 = 11.83 × 10−12 m2, k2 = 1.86 × 10−6 m) with ∼81.9% porosity and a good filtration efficiency of 89.81% for PM > 2.5 μm under an extremely low pressure drop (0.69 kPa). These results indicate that this approach could open a new avenue for the design and preparation of high performance porous ceramics suitable as filters in high temperature environments.