Fabrication And Electromagnetic Properties Of Spherical Fe₃O₄ Core-Shell Nanocomposite Material

Since the 21st century, electronic products have been used more and more widely, which leads to the serious electromagnetic wave pollution problem.In order to solve this problem, scientists made further efforts on electromagnetic wave absorbing materials,and tried to make these materials thinner,lighter,stronger and have wider absorb band.In this paper,core-shell structure material based on Fe3O4(core) and ZnO(shell) wasfabricated and its absorption property was studied.Fe3O4 we fabricated is a nanomaterialwith diameter of 300nm,saturation magnetization(Ms) of 85.5emu/g and coercive force(Hc) of 45Oe.When the simulated thickness was 5.5mm,its highest absorption peak is around 5.58GHz.The core-shell structure of Fe3O4@ZnO was fabricated by sol-gel method,and this structure was confirmed by SEM,EDS,XRD and IR spectra analysis.Its absorption wave analysis,indicated that after adding ZnO.when the simulated thickness was5.5mm,3mm and2.5mm,its highest absorption peak is in the frequency 9.1GHz,14.8GHz and 17.7GHz.Polyaniline (PANI) was grown on Fe3O4@ZnO by in situ composition.The mass ratio of Fe3O4@ZnO was 5%,10% and 15% as the amount of aniline changed, and the absorption performance was studied repectively. SEM images showed that the polyaniline was tubulous with diameter of 50nm and Fe3O4@ZnO was wrapped inside.XRD images showed that the polyaniline was grown on the Fe304@ZnO.Absorption analysis showed that after adding PANI, when Fe3O4@ZnO quality ratio is 10%, the nanocomposite had the highest reflection loss as-16.6 dB,mainly in the frequency band of 12-18GHz.In order to study the effect of graphene on the wave absorption properties, the physical mixing of Fe3O4@ZnO/PANI and graphene was carried out by physical mixing method,and the mass ratio of grapheme is interspersed with the structure of Fe3O4@ZnO/PANI.Through the analysis of the absorbing properties, it can be found that after adding grapheme,the complex dielectric constant real part and the i part has increased indicating that the preparation of graphene can improve the conductivity of the complexes.