Preparation Of Nano Fe₃O₄/Carbon Aerogel And Research On Its Absorption Properties

Absorbing materials can achieve good electromagnetic wave absorption and loss through two absorbing mechanisms of dielectric loss and magnetic loss.Traditional absorbing materials mainly use magnetic metal oxides such as ferrite and barium titanate.These materials tend to have high density,poor modifierability,and low chemical stability,which greatly limits the application breadth and depth of absorbing materials.The emergence of new wave-absorbing materials,such as its"thin,light,wide,and strong"functional characteristics,provides a turning point for this problem.Graphene aerogel is a new type of carbon material.The 3D porous structure makes the graphene aerogel have excellent flexible mechanical properties and good chemical modifiability,which makes the use of graphene aerogel to achieve composite absorbing materials may.The loss mechanism of graphene aerogel to electromagnetic waves is mainly dielectric loss,while metal oxides such as Fe₃O₄ are mainly magnetic loss.Therefore,this study intends to use the chemical modifiable properties of graphene aerogels to combine graphene aerogels with nano-Fe₃O₄,and to achieve the preparation of Fe₃O₄/graphene composite aerogels by adjusting the content of nano-Fe₃O₄.The study of its mechanics and absorbing properties provides a certain research basis for the research of lightweight and efficient absorbing materials.The main research contents are as follows:(1)On the basis of preparing a large-diameter graphene oxide solution,the nano-Fe₃O₄ particles are mixed with it,and the Fe₃O₄/graphene composite aerogel is prepared by the method of hydrothermal and freeze-drying reduction,which realizes that Fe₃O₄is in the graphene gas.Effective doping and uniform dispersion in the gel.Through the preparation and adjustment of different proportions of Fe₃O₄content(10 wt%,20 wt%,50 wt%),and through the test of various parameters of the wave absorption,it is found that when the content of Fe₃O₄ increases,the loss intensity of the composite aerogel to the incident electromagnetic wave increases,and When the Fe₃O₄content is 20 wt%,the composite aerogel has the best absorption effect for incident electromagnetic waves,and generally has a good absorption capacity in the frequency range of 2-18 GHz,and its reflection loss can reach the minimum value-28d B,indicating that the composite aerogel has an absorption rate of more than 99%for incident electromagnetic waves.(2)Carbon nanotube-based aerogel has excellent mechanical,electrical and magnetic properties.On the basis of the graphene oxide(ethanol)solution mixed with Fe₃O₄,the graphene oxide(ethanol)solution is immersed into the carbon nanotube aerogel by pressure to achieve uniform diffusion of the graphene oxide in the carbon nanotube aerogel And distribution,after hydrothermal reduction,prepared into carbon nanotubes to enhance Fe₃O₄/graphene aerogel,so as to further enhance the mechanical and wave absorbing properties of composite aerogel.By testing the mechanical and absorbing properties of the reinforced composite aerogel,the study found that the composite aerogel can achieve enhanced mechanical properties after doped with graphene containing Fe₃O₄,and at low frequencies,the material has the ability to resist incident electromagnetic waves.Larger loss capacity,and in a wider frequency range,has stronger absorption capacity for incident electromagnetic waves,and its maximum absorption rate can reach more than 99%,showing excellent wave absorption protection performance.