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.

Automated summary

This study obtained a unique three-dimensional carbon foam structure by carbonizing melamine foam, and further improved its microwave absorption properties by adding Fe3O4 magnetic nanoparticles. Adjusting the amount of Fe3O4 nanoparticles can achieve different microwave absorption performances, with the best absorption observed at a mass ratio of 6:4. The combination of carbon materials and magnetic particles enhanced the impedance matching performance and provided new ideas for designing high-performance absorbing materials.