Enhanced microwave absorption properties of carbon nanofibers functionalized by FeCo coatings

Carbon nanofibers (CNFs) functionalized by ferromagnetic metals possess many potential applications in the microwave absorption. In this study, CNFs were functionalized by FeCo coatings with a DC-magnetron-sputtering method. The phase composition, microstructure, magnetic properties and electromagnetic wave absorbability of the new composites (FeCo/CNFs) have been studied. The obtained results demonstrate intensity magnetism in FeCo/CNFs, where the maximum saturation magnetization reaches up to 3.23 emu/g, and the minimum coercivity is 161.27 Oe. For the sample with a thickness of 4 mm, two absorption peaks located in the range of 3.81-4.36 GHz and 14.03-16.35 GHz can be observed. While the optimized reflection loss value of -24.05 dB was found at 14.88 GHz. Compared with the pristine CNFs, FeCo/CNFs exhibit stronger absorption and wider absorption band, because of the introduced FeCo coatings as well as the destructive interference between FeCo and CNFs. The method developed in this study will pave a new way for the development of CNF-based electromagnetic-wave absorbing materials.