Preparation And Microwave Absorption Properties Of Two-dimensional Porous Fe Based Nanosheet Materials

With the wide application of electromagnetic technology,electromagnetic radiation and electromagnetic interference have become an inevitable problem.Microwave absorbing materials can effectively absorb electromagnetic waves and dissipate them into heat energy,which can effectively reduce the impact of electromagnetic waves on the environment and human body.So it has attracted extensive attention.?-Fe₂O₃ as a special crystal form of iron oxide,not only has good dielectric loss ability of iron oxide,but also has its special magnetic loss ability,which is not possessed by most microwave absorbing materials.But simple?-Fe₂O₃ limits its development potential in microwave absorption due to its large relative absorption thickness and relatively low absorption intensity.In this paper,two-dimensional porous magnetic oxide nanosheets were successfully prepared through a simple and reasonable experimental scheme,The relationship between the composition,morphology,composition and construction defects of?-Fe₂O₃ and the microwave absorption properties of the material was studied.The main research contents are as follows:1.In order to improve the microwave absorption capacity of?-Fe₂O₃,two-dimensional?-Fe₂O₃ magnetic oxide nanosheets were synthesized by two-step calcination.On the basis of the original feeding,trace aluminum was added into the?-Fe₂O₃ lattice,and then two-dimensional aluminum doped?-Fe₂O₃ magnetic oxide nanosheets were etched by alkali solution,two dimensional porous structure is obtained.The two-dimensional porous magnetic oxide material shows excellent microwave absorption performance.When etched with NaOH solution for one hour,the best emission loss is-52.4d B,the best matching thickness is only 2.2mm,and the best bandwidth is 5.12GHz.The main reasons for the improvement of microwave absorption performance of the material are that the interface polarization and dipole polarization of the material are improved by morphological adjustment,and the defects formed by etching improve the conductivity polarization ability of the material,and various polarization mechanisms interact with each other.2.According to the synthesis method of two-dimensional porous Al-Fe₂O₃magnetic oxide nanosheets,porous FeCoAl nanosheets were successfully prepared by adding magnetic element cobalt on the basis of original feeding.The addition of magnetic elements effectively improves the magnetic loss capacity of the material.The microwave absorption performance has been greatly improved.The test results show that the addition of a small amount of magnetic elements has a direct impact on the effective absorption bandwidth.When 5%cobalt element by weight is added to the original feeding,the reflection loss is-26.3d B and the effective absorption bandwidth is 5.68GHz when the matching thickness is 2.5mm.When the matching thickness is 3mm,The effective absorption bandwidth is 7.92GHz.It covers part of the X band and almost all of the Ku band.In summary,this paper synthesized two-dimensional porous magnetic oxide nanosheets through simple and effective experimental scheme,and proved through a series of experiments that the doping of trace magnetic elements can effectively improve the magnetic loss effect of the material and improve the effective absorption bandwidth of the material,and the performance of pure?-Fe₂O₃ has been significantly improved.