One-dimensional carbon/SiC nanocomposites with tunable dielectric and broadband electromagnetic wave absorption properties

In this work, 1D carbon/SiC nanocomposites were fabricated by the electrospinning of polycarbosilane (PCS) and polyvinylpyrrolidone (PVP) with subsequent polymer pyrolysis and annealing treatment. The dielectric properties and electromagnetic (EM) wave absorption performance of the nanocomposites were studied over the frequency range of 2-18 GHz. By controlling the weight ratio of precursor PVP, both the dielectric loss ability and microwave absorption performance of the nanocomposites were improved. The nanocomposites obtained from 4.3 wt% PVP exhibited excellent EM performance, their optimal reflection loss (RL, in dB unit) value reached as high as −57.8 dB at a coating thickness of 1.9 mm. In addition, the nanocomposites displayed an ultrawide effective absorption bandwidth (EAB, RL below −10 dB, 90% EM attenuation) of 7.3 GHz at an absorber coating thickness of 2.7 mm. It was found that the carbon defects, SiC nanocrystals, and heterojunction interfaces among carbon, SiC, and amorphous SiOxCy contribute to the nanocomposite's outstanding EM performance. The low RL values and wide absorption bandwidth of the carbon/SiC nanocomposites make it a good candidate as highly efficient radar wave absorbers under harsh conditions.

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