Abstract: rGO/CoFe₂O₄ nanocomposites were prepared at a lower temperature in a short period of time based on the combination of double-membrane dispersion technology and hydrothermal method in this paper, and its wave absorbing properties were also studied. Characterization was carried out by XRD, SEM, EDS, TEM, TG/DSC, and IR testing methods. Vector network analyzer was used to measure the changes of complex permittivity and complex permeability of the composites in the frequency range from 2GHz to 18GHz, and the microwave attenuation performance were simulated by computer under different thicknesses of materials. The results showed that uniform size of CoFe₂O₄ nanoparticles were loaded on the surface and the edge of transparent and silk-like graphene sheet; the reflectance loss of single CoFe₂O₄ was only -3.59dB, while the microwave absorption of the sample, with quality ratio of CoFe₂O₄/GO being 10:7, was significantly enhanced when absorber thicknesses between 2mm and 3mm. The maximum microwave frequencies attenuation value of this sample can be obtained at -9.2dB at absorber thickness of 3mm, and the microwave absorption peak moved to the lower frequency region along with the increasing of thickness of absorbing layer. Comparing to single nanometer CoFe₂O₄ power, the absorption of electromagnetic waves for rGO/CoFe₂O₄ nanocomposites has been increased significantly.

Key words: graphene, CoFe₂O₄, nanoparticles, composites, membranes, electromagnetic wave absorption

摘要： 基于双膜分散技术与水热法相结合的思想,在较低温度条件下,短时间内合成了还原的氧化石墨烯(rGO)/CoFe₂O₄纳米复合材料,并研究了rGO/CoFe₂O₄的吸波性能。通过 XRD、SEM、EDS、TEM、TG/DSC、IR测试手段对rGO/CoFe₂O₄进行表征,采用矢量网络分析仪测定了复合材料在2~18GHz范围内复介电常数和复磁导率的变化,并利用计算机模拟材料在不同厚度下电磁波的衰减性能。结果表明:在透明绢丝状石墨烯的表面及边缘负载了粒度均匀的纳米CoFe₂O₄粒子;单一纳米CoFe₂O₄的反射率损耗为-3.59dB。而mCoFe₂O₄:mGO为10:7的样品的吸波层厚度在2~3mm之间变化时,微波吸收效果显著增强,厚度为3mm时,出现最大微波衰减值-9.2dB,并且微波吸收峰随着吸波层厚度的增加而向低频移动。相比于单一纳米CoFe₂O₄粉体,rGO/CoFe₂O₄纳米复合材料对电磁波的吸收效果有了大幅度的提高。

关键词: 石墨烯, CoFe₂O₄, 纳米粒子, 复合材料, 膜, 电磁波吸收