Efficient high-temperature electromagnetic wave absorption enabled by structuring binary porous SiC with multiple interfaces

Introducing enhanced interface polarization would be an effective way to adjust the dielectric behavior with temperature and prepare high-temperature electromagnetic (EM) wave absorbers. Herein, carbon nanotube (CNT)-derived binary porous SiC with multiple interfaces was successfully fabricated by structuring SiC nanowire networks in porous SiC skeleton. The amount of secondary SiC nanowires and electronic structures of the as-received binary SiC were changed by different heat temperatures. The positively correlated relationship of the ID/IG value of Raman spectrum and unoccupied density of states in the C K-edge was manifested by structuring SiC nanowire networks. The synergism of CNT-derived SiC nanowires and SiC skeleton improved the formation of multiple interfaces and propagation path. These enhanced dielectric properties could induce high-temperature EM wave absorption performance of the fabricated binary porous SiC. For instance, the minimum reflection loss (RLmin) of -47.0 dB was achieved at 1.8 mm thickness in frequency range of 9.3-12.4 GHz. The optimum RL could reach -51.0 dB at 8.6 GHz, when the temperature increased to 600 degrees C. Meanwhile, structuring SiC nanowire networks substantially increased the compressive strength. This multi-function of the CNT-derived binary SiC indicated that they were outstanding materials with potential applications in EM wave absorption at high temperatures. (C) 2020 Elsevier Ltd. All rights reserved.