Research On Microwave Absorbing Performance Of Carbon Fiber/CoNi Alloy Composite

With the development of communication and electronic information technology,which has brought great convenience to human life,the electromagnetic pollution generated has also seriously affected human health and living environment.Therefore,the study of absorbing material is of great significance.In this paper,carbon fiber with electrical loss was composited with magnetic metal particles with magnetic loss,and carbon fiber/Ni composites and carbon fiber/CoNi alloy composites were prepared by solvothermal method and hydrothermal method.By changing the reaction time and the content of metal particles,the electromagnetic parameters and absorbing properties of the composite were regulated.XRD,SEM,EDS,Raman,VNA and other analysis and measurement methods were used to systematically study the microstructure morphology,electromagnetic parameters and loss mechanism of the composite materials,and obtained absorbing materials with excellent performance.The main results are as follows:Carbon fiber/Ni composites were prepared by solvothermal method.The addition of magnetic nickel particles can effectively improve the impedance matching,increase the peak reflection loss of the composite material,and significantly improve the wave absorbing performance.At 5.5 GHz,the minimum reflectivity peak can reach-32.8 d B,and the effective absorption bandwidth is 1.65 GHz.In the CFs/CoNi alloy composites prepared by solvothermal method,magnetic CoNi alloy particles of heterogeneous mass phase were generated on the surface of carbon fiber,and the metal particles showed an irregular loose flocculent structure,which was not tightly combined with the surface of carbon fiber.With the increase of CoNi alloy content,the reflection loss peak of the composite material gradually moves to the high frequency direction.When the sample thickness is 1.2 mm,the minimum reflection loss value of the composite material at 17.1GHz frequency is-55.4 d B,and the effective absorption bandwidth can reach 4.1 GHz.Carbon fiber/Ni composites were prepared by hydrothermal method,and the reaction rate of nickel ions in solution was faster and the reaction time was shorter.The carbon fiber/CoNi alloy composite was prepared by hydrothermal method.The shell layer of the composite material is well combined with the surface of carbon fiber,and the surface is uniform,complete and the phenomenon of large particle aggregation appears.With the increase of CoNi alloy content,the particles on the carbon fiber surface appear large scale adhesion phenomenon.When the sample thickness is 1.5 mm,the minimum reflection loss value of the composite material at 13.0 GHz frequency is-48.1 d B,and the effective absorption bandwidth can reach 3.1 GHz.The microstructure,electromagnetic parameters and loss mechanism of the composites prepared by solvothermal and hydrothermal methods were compared and analyzed.Because of the different surface morphology of composite materials,the propagation path of electromagnetic wave in the material will change,thus affecting the electromagnetic parameters and the wave absorbing performance of the composite material.By controlling the particle size and shell thickness is an effective way to optimize the electromagnetic parameters of the material,increase the loss of the material to electromagnetic waves and improve the wave absorbing performance of the composite material.