Preparation And Electromagnetic Characteristics Of MXene/Co_0.5Ni_0.5Fe₂O₄ Composite Materials

Microwave absorption material is a kind of functional material which can absorb incident electromagnetic wave to the maximum extent,and interact with electromagnetic wave to convert electromagnetic wave into heat energy and other forms of energy.It is applied widely to national defense and civil industry.At present,microwave absorption material is developing in the direction of"thin,light,wide and strong".Ferrite has attracted more and more attention in the field of microwave absorption material because of its low price,high absorptivity and thin coating.However,its application in the field of microwave absorption material is limited because of its high density and narrow frequency band.At present,the research and development of graphene and two-dimensional graphene analogues have widened the field of microwave absorption material and received extensive attention and research.MXene is a novel two-dimensional carbon/nitride material with a layered structure similar to graphene,with excellent electrochemical performance and adjustable interlayer spacing due to its large specific surface area.It is a kind of electromagnetic microwave absorption material with great research value and potential.In this paper,Co_0.5Ni_0.5Fe₂O₄ was induced to grow between Ti₃C₂ layers by hydrothermal synthesis and multilayer lamellar structure of MXene.The composite of Ti₃C₂/Co_0.5Ni_0.5Fe₂O₄ microwave absorbing materials with different loss mechanism was realized.The effects of the preparation process of MXene,the conditions of hydrothermal compounding,and the ratio of different composition on the structure and absorbing properties of MXene were studied.The specific content and main conclusions are as follows:1.Ti₃C₂ layered materials were prepared by etching Ti₃AlC₂ with HF acid chemical liquid etching method and were treated by centrifugation and ultrasonic vibration respectively.The effect of etching time and concentration of HF acid etchant on microstructure and phase composition was studied.Optimum process conditions for preparation of MXene:The best etching conditions for obtaining Ti₃C₂ are 40%HF acid etching for 24 h;For expanding layer of Ti₃C₂ phase,the effect of ultrasonic vibration driving the interlaminar van der Waals force fracture Ti₃AlC₂.Al phase can be better removed from the layer to achieve the effect of expanding layer.2.The Ti₃C₂/Co_0.5Ni_0.5Fe₂O₄ composite materials were successfully prepared by hydrothermal method.The relationship between the thickness of absorbing layer,the content of Ti₃C₂,the frequency and the electromagnetic absorbing Characteristics of the composite materials were studied.It can be found that the complex dielectric constantεincreases with the increase of Ti₃C₂ content,which indicates that the addition of Ti₃C₂ has a large dielectric loss on the whole composite absorbing material.With the increase of Ti₃C₂ content,the complex permeabilityμwill become smaller.With the increase of frequency,the complex permeability will be fluctuated,showing a certain dispersion effect,which is conducive to broaden the absorption band of absorbing materials.In the 2-18 GHz frequency range,the overall absorption capacity of the composite materials are obviously higher than that of the pure ferrite phase.When the thickness of the absorbing layer is 4.5 mm and Ti₃C₂ is 30%and40%,the total absorption capacity of the composite is better than that of the pure ferrite phase.The peak absorptivity is-3.6 dB and-3.8 dB,respectively.The Ti₃C₂/Co_0.5Ni_0.5Fe₂O₄composite material show good microwave absorbing effect.