Study On Preparation Of Carbon-based Magnetic Composite By Deflagration Method And Its Electromagnetic Wave Absorption Properties

With the continuous development of science and technology,the 5G era has come,and the application of electromagnetic waves has been involved in various fields,especially in industrial production,medical diagnosis,and national defense construction.However,electromagnetic pollution has become increasingly prominent and has brought a huge threat to our living environment and national defense security.Therefore,the development and design of high-performance electromagnetic wave absorbing materials has been the research focus in recent years.Carbon materials have excellent dielectric properties,while magnetic particles have good magnetic properties.The dielectric constant and permeability of the materials can be effectively controlled by means such as compounding to achieve impedance matching and attenuation characteristics at the same time.Therefore,the magnetic metal/carbon-based nanocomposite is still the most ideal absorbing material.However,traditional preparation methods still have many shortcomings,such as a large amount of time consumption,high power dissipation,and low production efficiency.Therefore,the synthesis of such nanocomposite materials is still a huge challenge.Based on this,this paper proposes an ultra-fast energetic metal-organic framework(EMOF)deflagration method,which releases huge heat through one-step thermal decomposition,converts EMOF into magnetic nanoparticles,and simultaneously converts graphene oxide(GO)into reduced graphene oxide(rGO).The main contents are as follows:(1)The EMOF was prepared by the co-precipitation method;and the EMOF/GO deflagration precursor was synthesized by introducing GO.Study the influence of GO on the morphology and structure of EMOF,and use high-speed camera to explore the deflagration characteristics of EMOF/GO.The results show that the introduction of GO can reduce the accumulation of E-MOF and make it uniformly dispersed on GO;and the introduction of GO can promote the decomposition of E-MOF during the deflagration process,and at the same time provide a large number of nucleation sites for the deflagration product,which is conducive to uniform dispersion of nanoparticles and reduces agglomeration.(2)Using Fe-BTO/GO as the precursor,Fe₃O₄ ultrafine nanoparticles were quickly prepared by the deflagration method and dispersed evenly on the reduced GO,and finally Fe₃O₄/rGO composite materials were obtained.To study the influence of the relative content of Fe-BTO:GO on the composition,morphology and microwave absorbing properties of deflagration products.The results show that when the molar ratio of Fe-BTO:GO is 6:1,the minimum reflection loss RL of the material can reach-67.1 d B,and the thickness matching is only 2.2 mm.The reason for the best absorption performance:the introduction of Fe₃O₄ makes the composite material achieve good impedance matching,so electromagnetic waves can enter the material to the maximum;at the same time,the magnetic loss caused by the natural resonance of Fe₃O₄ nanoparticles,and the interface polarization between Fe₃O₄ and rGO can consume electromagnetic wave energy as much as possible.(3)Using FeCo-BTO/GO as the precursor,FeCo alloy nanoparticles were quickly prepared by the deflagration method and dispersed uniformly on the reduced GO,and finally FeCo/rGO composite materials were obtained.To study the influence of the relative content of FeCo-BTO:GO on the composition,morphology and microwave absorbing properties of deflagration products.The results show that when the molar ratio of FeCo-BTO:GO is 4:1,the minimum reflection loss RL of the material can reach-62.03 d B,and the matching thickness is3.15 mm.The reason for the best absorption performance:the introduction of FeCo nanoparticles greatly improves the impedance matching of composite materials;at the same time,FeCo nanoparticles can generate magnetic loss through eddy current loss and natural resonance,and the interface polarization between FeCo and rGO can consume electromagnetic wave energy as much as possible.