石墨烯装载不同含量钴锌铁氧体及其电磁行为对比

Comparison of Electromagnetism Behavior of Different Content Cobalt-zinc Ferrite Loaded with Graphene

以天然鳞片石墨为原料制备氧化石墨(GO),应用水热法制备钴锌铁氧体(Co_(0.5)Zn_(0.5)Fe_2O_4),并将两者制备成石墨烯(rGO)/Co_(0.5)Zn_(0.5)Fe_2O_4复合材料。采用X射线衍射(XRD)、拉曼光谱(Raman)、红外光谱(FT-IR)研究rGO/Co_(0.5)Zn_(0.5)Fe_2O_4的结构;应用透射电子显微镜(TEM)和矢量网络分析仪(VNA)研究不同复合比例对rGO/Co_(0.5)Zn_(0.5)Fe_2O_4复合材料形貌、电磁损耗特性、德拜弛豫模型及电磁响应行为的影响。结果表明:复合反应后的GO在XRD图谱中主衍射峰由2θ=9.74°变化为2θ=24.15°,且红外光谱图中显示含氧官能团消失,均说明GO成功还原为rGO。透射电子显微镜图中可以看到Co_(0.5)Zn_(0.5)Fe_2O_4嵌布在rGO上。复合反应过程中,当钴锌铁氧体的含量增大,分散性逐渐减弱。Co_(0.5)Zn_(0.5)Fe_2O_4与GO质量比为2:1时制备的rGO/Co_(0.5)Zn_(0.5)Fe_2O_4复合材料的吸波性能最佳,在15.11 GHz处反射率达到最小值-36.89 dB,有效吸波频带宽为3.74。

A kind of graphene composite(rGO/Co0.5Zn0.5Fe2O4) was synthesized with the graphene oxide(GO)prepared from natural flake graphite and cobalt-zinc ferrite(Co0.5Zn0.5Fe2O4) manufactured by the hydrothermal method. The structure of composites was characterized by X-ray diffraction(XRD), Raman spectrometer(Raman)and the Fourier-transform infrared spectroscopy(FT-IR). Morphology, electromagnetic loss properties, Debye relaxation, and microwave absorbing properties of rGO/Co0.5Zn0.5Fe2O4 were investigated by transmission electron microscope(TEM) and vector network analyser(VNA). Sharp peak of graphene oxide was changed from 2θ=9.74°to 24.15° in the XRD patterns and the oxygen functional group disappeared after the composite reaction, which demonstrated that GO was successfully reduced to rGO. The graphene was embedded with cobalt-zinc ferrite, observed by transmission electron microscope, with its dispersion worse with the loaded Co0.5Zn0.5Fe2O4 increasing.Absorbing property of rGO/Co0.5Zn0.5Fe2O4 composite prepared with w(Co0.5Zn0.5Fe2O4) : w(GO)= 2 : 1 is the best with the minimum reflectivity of -36.89 dB at 15.11 GHz and the effective absorption frequency bandwidth of 3.74.