Synthesis and microwave absorption properties of multilayer SiC/C foam with alternating distribution of C and SiC

•We designed a multilayer SiC/C foam with alternating distribution of C and SiC.•The MSCF showed a minimum RL value of −49.15 dB at 15.6 GHz at 1.4 mm.•The microwave absorbing mechanism of the MSCF was proposed.•The multilayer SiC/C structure possesses greater potential in the microwave absorbing field.•It provided actual guidance for the microstructure design of excellent EM absorbers. [Display omitted] The multilayer SiC/C foam with alternating distribution of C and SiC (MSCF) was designed, which was planned to be a outstanding microwave absorber. The melamine-derived light carbon foam (CF) was determined to be the initial porous template. The multilayer SiC/C structure was synthesized by depositing chemical vapor deposition (CVD) of SiC, pyrolytic carbon (PyC) and SiC coatings sequentially on CF skeletons. SEM and XRD results showed that the multilayer SiC/C structure with alternating distribution of C and SiC was successfully prepared. A large number of heterogeneous interfaces formed between the carbon and SiC layers, which was the key to improving the microwave absorbing performance. As expected, the resulting MSCF showed satisfactory impedance matching ratio (Zr) and an optimal reflection loss value of −49.15 dB at 15.6 GHz with the thickness of 1.4 mm. Moreover, the corresponding effective absorption band covered the frequency range of 13.98–17.78 GHz. Furthermore, the microwave absorbing mechanism based on the multilayer SiC/C structure was proposed. Under the guarantee of the high value of Zr, the multiple reflections and scattering, dipole polarization, and interface polarization played a synergistic effect in the multilayer SiC/C structure.