Materials with high-strength, lightweight, excellent thermal stability and high-efficiency electromagnetic interference (EMI) shielding performance are highly desired for practical shielding applications, especially in areas of aerospace and aircraft. Herein, a light but strong SiC foam with hierarchical porous architecture are fabricated by using dough or bread as raw material via carbonization and followed carbothermal reduction with silicon source. The fabricated SiC foam contains nano-, meso- and micro-sized porosities. Strikingly, meso and nano pores are embedded in micro-sized porous skeleton. This three-level hierarchical porous skeletons constitute the load-bearing structural units at gradually smaller length scales, which provides a means for dissipating strain. A significant synergistic among these hierarchical porous architecture endows the SiC foam with high-performance EMI shielding and thermal insulation. EMI shielding can be higher than 20 dB and specific EMI effectiveness exceeding 24.8 dB cm3 g−1 in the frequency of 11 GHz at 25−600 °C, which is 3 times higher than dense SiC ceramic. The thermal conductivity reaches as low as 0.02 W m−1 K−1, which is comparable to aerogel. But the compressive strength is as high as 9.8 MPa. Considering the chemical and high-temperature stability of SiC, the fabricated SiC foam is a promising candidate for modern aircraft and automobile applications.

Light but strong SiC foam for thermal insulation and electromagnetic interference shielding at elevated temperatures

255th National Meeting (2018)

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