Synthesis and microwave absorption properties of sulfur-free expanded graphite/Fe3O4composites

Abstract

In this study, sulfur-free expanded graphite (EG) was obtained by using flake graphite as the raw material, andEG/Fe3O4 composites with excellent microwave absorption properties were prepared by a facile one-pot co-precipitation method. The structure and properties of as-prepared EG/Fe3O4 were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR), X-ray diffraction (XRD), Raman, X-ray photoelectron spectrometry (XPS), thermogravimetric (TG), and vibrating sample magnetometry (VSM) characterizations. The Fe3O4 intercalated between the layers of expanded graphite forms a sandwich-like structure which is superparamagnetic and porous. When applied as a microwave absorber, the reflection loss (RL) of EG/Fe3O4 reaches -40.39 dB with a thickness of 3.0 mm (10 wt% loading), and the effective absorption bandwidth (EAB