Effect of SiC layer on microwave absorption properties of novel three-dimensional interconnected SiC foam with double-layer hollow skeleton

Abstract

To design a lightweight and high-performance absorber, this work introduced a novel threedimensional interconnected SiC foam with double-layer hollow skeleton (3D-ISF), which was prepared by depositing SiC, pyrolytic carbon, and SiC layer on interconnected carbon foam, followed by oxidation of carbon. SEM results showed the interconnected hollow structure had been successfully synthesized, which was beneficial for microwave absorbing efficiency, and numerous columnar SiC defects were observed and played a critical role in the microwave absorption properties. The electromagnetic performances of 3D-ISF-I and 3D-ISF-II were investigated in depth. With the increase of thickness of SiC layer, 3D-ISF-II exhibited a better microwave absorption property, which could be ascribed to the higher impedance matching ratio (Z r ) and attenuation constant (α). The optimum reflection loss value of 3D-ISF-II could reach −45.649 dB while that of 3D-ISF-I was just −32.070 dB. There is no doubt that the prepared materials have tunable microwave absorbing properties, which can promote the development of SiC-based absorbing materials to a certain extent. Finally, it was confirmed that the Z r played a dominant role in 3D-ISF, which provided practical guidance for the design of porous materials.

A microstructure-driven magnetic composite for excellent microwave absorption in extended Ku-band

“…49–51 Therefore, a higher value of ε ′′ leads to an increment in the σ AC , which in return will increase the skin depth effect, resulting in undesired reflection of EMW. 52 For this reason, PHPBR1-1 shows a better SE A capacity than the other two composites.…”

Enhanced mechanical and wave‐absorption properties of SiC–Si3N4–FeSi porous ceramics by introducing Al

“…The sharp fluctuations of the eddy current loss $${C}_0$$ curves (defined by Equation S4 32 ) in Figure 5H prove this conclusion. However, the excessively high complex permittivity of FeSi makes its impedance match with free space poor (Figure 5I), and the lower value of impedance matching ratio $${Z}_{\mathrm{r}}$$ (defined by Equation S5 33 ) limits the efficient absorption of electromagnetic waves in SiC–Si 3 N 4 –FeSi porous ceramics (S2). The introduction of Al improves this problem, and the complex permittivity of S3 is reduced compared to S2.…”

Polysilazane hybrid phenolic resin ceramic aerogels with excellent electromagnetic wave absorption performance

“…One of the possible ways toward this goal is to utilize special microstructures (i.e., porous, layered, and three‐dimensional [3D] network structures) by providing rich heterogeneous interfaces to achieve excellent EMW absorption performance 20–22 . For example, multifunctional aerogels with unique porous structures and adjustable microstructure have been widely documented, which could be used for boosting EMW absorption 23–27 .…”

“…[15][16][17][18][19] One of the possible ways toward this goal is to utilize special microstructures (i.e., porous, layered, and three-dimensional [3D] network structures) by providing rich heterogeneous interfaces to achieve excellent EMW absorption performance. [20][21][22] For example, multifunctional aerogels with unique porous structures and adjustable microstructure have been widely documented, which could be used for boosting EMW absorption. [23][24][25][26][27] Moreover, ceramic aerogel is an ideal EMW absorbing material relying on the 3D nanonetwork structure and excellent high-temperature resistance performances, which could achieve effective dissipation and absorption of electromagnetic waves.…”