Preparation And Properties Of Magnetic Functionalized Graphene Three-dimensional Absorbing Materials

Because of the unique two-dimensional crystal structure graphene has excellent optical,electrical and mechanical properties,which means it has important application prospects in materials science,micro/nano processing and energy.Using two-dimensional graphene nanosheet as basic structural unit to construct a three-dimensional graphene macroscopic body material,which has a series of advantages such as rich pores,large specific surface area,small density,high electrical conductivity,good mechanical compressibility and structural stability.It brings new opportunities and challenges to the development and application of carbon materials in the field of stealth technology.By introducing magnetic nano-components into graphene to build magnetically functionalized three-dimensional graphene micro-nano composite wave absorbing materials can effectively improve the electromagnetic matching characteristics of graphene and its ability to absorb and attenuate electromagnetic waves.Therefore,it has become an ideal absorbing functional material with great application potential.In this paper,using two-dimensional graphene oxide as precursor,two kinds of three-dimensional graphene loaded with magnetic Fe₂O₃nanoparticles?3D-EA-rGO@Fe₂O₃and 3D-DEG-rGO@Fe₂O₃?are constructed by solvothermal method under the action of different auxiliary agents ethanol?EA?and diethylene glycol?DEG?.Without the aid of any reducing agent,the self-assembly of three-dimensional graphene and the in situ reduction of magnetic nanoparticles were achieved in one step.X-ray diffraction?XRD?,X-ray photoelectron spectroscopy?XPS?,scanning electron microscopy?SEM?,transmission electron microscopy?TEM?and vibration sample magnetometer?VSM?were used to study the phase structure,chemical composition,micro morphology,magnetic properties and mechanical rebound characteristics of three-dimensional magnetic graphene composites.The electromagnetic parameters of 3D magnetic graphene composites were tested by vector network analyzer.The effect of the magnetic components content on the absorption properties of 3D graphene composites in the frequency range of 1-18 GHz were systematically studied with Matlab software.Meanwhile,the mechanism of electromagnetic loss is discussed in depth.The research results show the two kinds of three-dimensional magnetic graphene composites have excellent absorbing properties and mechanical rebound properties.The3D-EA-rGO@Fe₂O₃composite material has a reflection loss of-71.05 dB at the thickness of2.45 mm and an effective absorption bandwidth of 5.87 GHz;The 3D-DEG-rGO@Fe₂O₃composite material has a reflection loss-63.86 dB at the thickness of 2.28 mm,the effective absorption frequency bandwidth is 5.53 GHz.Both can achieve more than 90%recoverable non-linear elastic compression deformation.The multiple interface structure of three-dimensional magnetic graphene composite materials provides more channels for electromagnetic wave propagation and attenuation.Multiple attenuation mechanisms such as Debye dipole relaxation,multiple interfacial polarization and eddy current loss,natural resonance,exchange resonance interactions of magnetic nanoparticles,which are conducive to improving the impedance matching characteristics and absorption attenuation properties of the three-dimensional magnetic graphene composite.