Preparation And Microwave Absorption Properties Of Fe₃O₄@BaTiO₃/RGO Composites

Currently, graphene-based multiple structure composites are the hot research topic in the field of microwave absorption. They can satisfy the requirements of new microwave absorbing materials, which are thin thickness, light quality, wide frequency band and strong absorption. In this paper, Fe3O4@BaTiO3/RGO composites were synthesized by two different preparation methods. By comparison with electron microscopy observation, the two-step solvothermal method was determined to be the best preparation method. The structure,morphology and composition of the composites were characterized by XRD、SEM、TEM、Raman and EDS, and explored and analysis of the magnetic and absorbing properties of the composites.Fe3O4@BaTiO3/RGO composites composed of uniform morphology of Fe3O4@BaTiO3 core-shell structure particles distributed on the RGO layer. The magnetic hysteresis measurement reveals composites have superparamagnetic character. The Fe3O4@BaTiO3/RGO composites exhibit excellent microwave absorption performance, when the matching thickness is 4 mm, the maximum absorption reflection loss of composites is up to -38.2 dB at 5.0 GHz and the effective absorption frequency width of 4.4～5.6 GHz.The composites in the range of 1.5～5.5 mm thickness effective absorption bandwidth is up to 13.9 GHz and the maximum absorption loss value corresponding to all thickness of samples exceed -20 dB. The composites have excellent microwave absorption properties in all frequencies make it has a good application prospect and theory value in microwave absorption field.The influences of reaction time, reaction temperature, the pH and surfactant on the morphology, forming, particle size and dispersion of the Fe3O4@BaTiO3/RGO composites were explored and obtained the best experimental conditions. The function and structure caused a variety of absorption mechanism work together to make the composites have excellent microwave absorption performance. The Fe3O4/BaTiO3 mole ratio and RGO content will affect absorbing properties of the composites. The results demonstrate that when the Fe3O4/BaTiO3 mole ratio of 1:1-3 and the content of RGO is 40～60 mg, the composites have the best microwave absorption performance. Moreover, for Fe3O4@BaTiO3/RGO composites, the microwave absorption properties can be tuned by varying the component ratio and thickness of the samples.