Electromagnetic response and microwave absorption properties of CF/Fe3O4 absorbing composites.

In this work, a unique three-dimensional framework structure of carbon foam (CF) was obtained by carbonizing melamine foam at a certain temperature, and its dielectric properties were studied. Then the microwave absorption properties were further improved by adding Fe₃O₄ magnetic nanoparticles. CF/Fe₃O₄ absorbing composites were obtained. The CF/Fe₃O₄ absorbing composites can obtained different electromagnetic parameters of CF/Fe₃O₄ by adjusting the addition amount of Fe₃O₄ nanoparticles. When the mass ratio of CF to Fe₃O₄ is 6:4, the microwave absorption performance is the best. With a thickness of 1.5 mm and a load of 20 wt% of the absorbing material, the reflection loss (RL) can reach − 19.0 dB at 15.7 GHz. When the thickness is 1.5 mm, the effective absorption bandwidth can reach 4.8 GHz (13–17.8 GHz). By adjusting the thickness, it can achieve effective absorption in the range of 3.5–18 GHz. The microwave absorption performance of the synthesized CF/Fe₃O₄ composites are attributed to the three-dimensional porous structure, which realizes multiple scattering and reflection. Various heterogeneous interfaces such as carbon-air and carbon-Fe₃O₄ nanoparticles lead to the abundant interface polarization. Not only that, the combination of carbon materials and magnetic particles also further improves its impedance matching performance. This work has not only obtained carbon-based/magnetic particle composite materials with relatively good performance, but also provided new ideas for the design of high-performance magnetic/dielectric composite absorbing materials. [ABSTRACT FROM AUTHOR]