Microstructure and Microwave Absorption Performance Variation of SiC/C Foam at Different Elevated-Temperature Heat Treatment

Abstract

The porous structure has been proved to be beneficial to improve the microwave absorption performance. In this article, the SiC coating reinforced carbon foam (SiC/C) was synthesized via the direct pyrolysis of melamine foam and chemical vapor deposition process of SiC coating. Then the wrapping architecture consisting of three-dimensional carbon foam and ultrathin SiC coating was annealed at elevated temperature. The result shows that the anneal temperature does have a big impact on the dielectric property as the real and imaginary permittivities remain at a certain level with the increasing heat treatment temperature and finally drop to a low level until 900 °C. After being heated at 900 °C, the SiC/C foam attains a minimum reflection loss value of −51.58 dB with a matching thickness of 3.60 mm at 8.96 GHz, which is enhanced by 30.88% compared with the raw SiC/C foam. It also possesses an effective bandwidth frequency of 10.84 GHz ranging from 7.16 to 18.00 GHz, which is ascribed to the three-dimensional hollow structure to improve the polarization relaxation and interfacial polarization. The superior microwave absorption performance guarantees the potential application of a promising efficient microwave absorber in the harsh realities.

Dual-Interfacial Polarization Enhancement to Design Tunable Microwave Absorption Nanofibers of SiC@C@PPy

“…As a typical ceramic material, due to the high-temperature resistance, oxidation resistance, corrosion resistance, and adjustable dielectric properties, silicon carbide (SiC) has been widely used as MA absorption material. − However, SiC is greatly limited in the MA field on account of the low dielectric properties. Generally, there are various methods to overcome this problem, such as morphology design (nanowires, − whiskers, and particles), surface modification (SiC/Co, SiC@NiO, rGO/SiC, HfC/SiC, and CNTs/SiC), and doping (Fe-SiC, N-SiC, and Al-SiC).…”

Dielectric Properties and Electromagnetic Wave Absorbing Performance of Single-Source-Precursor Synthesized Mo4.8Si3C0.6/SiC/Cfree Nanocomposites with an In Situ Formed Nowotny Phase

“…In addition, sample SC-D2-1500 °C without Mo also shows EMW absorbing capability (Figure S4c), but its RL min value is still much lower than that of the Mo 4.8 Si 3 C 0.6 /SiC/C free nanocomposites discussed above. Compared to other reported SiC-based materials (Figure ), ,,,,− the Mo 4.8 Si 3 C 0.6 /SiC/C free ceramic nanocomposites exhibit superior EM absorbing performance (RL = −59 dB) at a rather thin thickness (2.46 mm). Moreover, the EAB of Mo 4.8 Si 3 C 0.6 /SiC/C free nanocomposites is not broad enough, although it is still in the range of other reported materials (Figure ).…”

Fe/Fe3O4@mSiO2 Core–Shell Nanostructures for Broad-Band Microwave Absorption

“…This morphology variation of the core indicates that Fe particles generated from hydrogen-thermal annealing begin to agglomerate, as shown in Figure e. It is noteworthy that after thermal annealing, discontinuity appears in the interior of mSiO 2 , which might be due to reduction. − …”