▎ 摘　　要

We prepared magnetite nanoparticles by co-precipitation method and functionalized them by amine groups prior to hybridization with graphene oxide. The resulting nanocomposites Fe3O4-NH2/GO were prepared with three weight ratios: 1:1, 2:1, 3:1, [Fe3O4-NH2:GO], in order to compare their magnetic properties. We used different techniques to investigate the nanocomposites: Fourier-transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy and vibrating sample magnetometer (VSM). Our results show that the synthesized nanocomposites exhibit superparamagnetic behavior with magnetic saturation at room temperature of the order of similar to 51.52, similar to 55.85 and similar to 58.26 emu/g respectively, which is large in comparison with Fe3O4 nanoparticles with similar to 73.4 emu/g. Microwave absorption of nanocomposite absorber of 7.0 mm thickness showed a minimum reflection loss of -27.85 dB at 4.80 GHz. The band widths corresponding to reflection loss less than -10 dB (over 90% electromagnetic wave absorption) are 3.82 and 2.99 GHz (from 2.58 to 6.40 GHz and from 13.99 to 16.98 GHz). Therefore, our results demonstrate that the prepared Fe3O4-NH2/GO nanocomposites are promising for microwave absorption applications. (C) 2019 Elsevier B.V. All rights reserved.