Optimization And Experimental Study On Electromagnetic Wave Absorbing/shielding Properties Of Two Dimensional Transition Metal Carbides

With the integrated circuit system has been widely applied in many key fields,such as energy,transportation,industry,national defense and so on,the integrated density of the integrated circuit per unit area is increasing,and the volume is becoming smaller and smaller.This development trend will not only im prove the work efficiency of the integrated circuit,but also bring significant electromagnetic interference problems.Electromagnetic interference not only harms people's living environment and health,but also affects the operation of precision instrumen ts and circuits.Therefore,whether for civil or military consideration,it is urgent to develop high-performance electromagnetic wave absorbing and shielding materials.The main function of electromagnetic wave absorbing shielding material is to attenuate electromagnetic wave and realize electromagnetic protection.The mechanism is to reflect the electromagnetic wave of the incident material,or to transform the electromagnetic energy into other types of energy,for example,heat energy in the material.The main evaluation criteria for electromagnetic wave absorption and shielding include coating thickness,maximum protection depth,frequency band of materials and physical and chemical properties of materials.Metal based materials are the earliest electroma gnetic wave absorbing and shielding materials,but they have some disadvantages,such as high density,easy corrosion,narrow protection bandwidth and so on.Carbon material is an ideal candidate material for electromagnetic wave absorption and shielding.Carbon material generally has good conductivity,and its dielectric properties are easy to control,so it is an ideal dielectric loss absorbing and shielding material.However,However,the impedance matching performance of traditional carbon materials is poor,which hinders their further development in microwave absorption.Therefore,it is necessary to explore new electromagnetic wave absorbing and shielding materials with high efficiency and easy industrial production.As a new type of carbon material,two-dimensional transition metal carbides have attracted much attention in many application fields.In addition,the shape,geometry,microstructure and composition of the material are very important to its electromagnetic absorption performance.By optimizing the component and structure of the material absorber,the conductivity of the material can be remarkably changed and the dielectric constant of the composite can be adjusted to achieve broadband effective absorption.In this paper,two-dimensional transition metal carbides were synthesized successfully.The effects of the loss composition,morphology and geometry of two-dimensional transition metal carbides on the electromagnetic absorption and shielding properties were studied.The scope of this study contents are as follows:(1)Two-dimensional transition metal carbides were successfully prepared by hydrofluoric acid etching.This synthesis strategy is simple,controllable and stable.In this paper,the microstructure,material composition and electromagnetic properties of the two-dimensional transition metal carbides were tested by various characterization methods,and the relationship between the characterization and the loss mechanisms such as conduction loss and dielectric loss was analyzed.(2)The effects of etching time and mass fraction of two-dimensional transition metal carbides on their electromagnetic parameters and properties were investigated,and the electromagnetic simulation was carried o ut.It was found that this layered structure has very high impedance matching performance,which is conducive to the incidence of electromagnetic waves and multiple scattering and reflection,and there is a strong interface polarization between the layers,And the difference between different transition elements will also affect the microwave absorption performance.(3)The electromagnetic shielding performance of two-dimensional transition metal carbide materials is studied and simulated.It is found that the two-dimensional transition metal carbide materials show excellent conductivity and electromagnetic shielding efficiency.Besides the contribution of high electromagnetic wave reflection to electromagnetic shielding caused by high conductivity,the two-dimensional transition metal carbide also finds that this special layered structure can disperse electromagnetic waves among different layers,and increase the conduction path and scattering of electromagnetic wave is conducive to the loss of electromagnet ic wave,and make a large part of the contribution of electromagnetic shielding from the absorption of electromagnetic wave.