Preparation And Study On Absorbing Properties Of Carbon Fiber Modified Absorbing Materials

With the development of science and technology,the harm caused by electromagnetic radiation to the environment and human body is becoming more and more serious,and the emergence of electromagnetic wave absorbing materials can effectively curb the development of this kind of harm.In modern warfare,radar stealth technology based on electromagnetic absorbing materials has greatly improved the survivability and penetration ability of weapons and equipment on the battlefield,and is one of the important means to control the current war initiative.With the innovation of materials and technology,the performance of electromagnetic absorbing materials not only stops at the traditional "thin,wide,light and strong" four aspects,but also improves the comprehensive performance in all aspects.Therefore,the combination of various complementary materials and the design of the absorbing structure have become the focus of research and development in the field of electromagnetic shieldIn this paper,it is proposed to prepare the Fe@CF composite absorbing material and carbon fiber cloth/CIP composite absorbing material to overcome their respective shortcomings with the complementary advantages of CF and ferromagnetic materials.On this basis,a new multi-dimensional structure is designed to realize multiple electromagnetic loss mechanisms to improve the CF absorption performance.This technology can not only reduce the density of composite materials,but also make it have both electrical and magnetic losses,and can effectively widen the absorption band,improve the absorption performance.The main research contents and conclusions of this paper are as follows:The chemical plating method was used to modify the CF surface,and a layer of Fe nanosheet coating was deposited uniformly.The Fe@CF composite absorbing material was successfully prepared.The influence of morphology on the electromagnetic parameters of the Fe@CF composite wave absorbing material is also studied.The experiment shows that the discontinuous network formed by the Fe nanosheet structure improves the impedance matching performance of CF and the magnetic permeability of CF,and strengthens the magnetic loss capability of CF,where the magnetic loss of Fe@CF mainly comes from natural resonance.Through the study of the reflection loss of Fe@CF,it is found that in the frequency range of 2-18 GHz,when the CF mass fraction is 30 wt% and the thickness of the absorption layer is 1.5mm,the matching performance and loss ability are the best.The reflection loss value reaches a minimum of-36.89 d B at 11.67 GHz.For continuous carbon fiber modification,a carbon fiber cloth/CIP composite material based on silicone rubber was prepared.The content of carbon fiber and CIP has a great influence on the absorbing effect of the composite material.For the A specification carbon fiber,as the CIP content increases,the better the absorbing effect of the carbon fiber cloth/CIP composite material.When the CIP mass fraction is 60 wt%,the reflection loss reached a minimum of-34.83 d B at 6.36 GHz.The B specification carbon fiber has a CIP mass fraction of 40 wt%,which has the best absorbing effect,and the reflection loss reaches a minimum of-20.34 d B at 9.21 GHz.In addition,the carbon fiber arrangement has a significant relationship with the composite material's absorbing effect.When the two layers of carbon fiber cloth are orthogonally arranged in the composite material,the absorption effect of electromagnetic waves is more excellent than the parallel arrangement.When the CIP mass fraction is 40 wt% and two layers of A specification carbon fiber are orthogonally arranged,the Return loss can reach-42.35 d B at 13.31 GHz.For the two layers of B specification carbon fiber cloth,the orthogonal arrangement time is small,forming a large continuous surface.And the carbon fiber content is high,which becomes a strong reflection of the electromagnetic waveform,making the wave absorbing effect poor.In view of the shortcomings of the large thickness of the absorbing coating,this paper designs the absorbing structure of the Fe@CF composite material,and uses Comsol simulation software to simulate and analyze the absorbing structure.The results show that for the multilayer planar absorbing structure,when the matching layer is 1mm and the absorbing layer is 2 mm,the absorbing effect is the best,and the minimum reflection loss value of-22 d B is reached around 12 GHz,showing excellent wave absorption and structural designability.The Fe@CF composite absorbing material and carbon fiber cloth/CIP composite absorbing material studied in this paper can be well used in the electromagnetic shielding application of X-band.The simulation analysis of the absorbing structure can provide a reference for the design and preparation of subsequent absorbing metamaterials.