Synthesis And Electromagnetic Wave Absorbing Performance Of Flexible Composite Materials Based On Magnetic Alloys

With the development of electronic information technology and wearable electronic devices,the research and application of flexible wave-absorbing materials are increasingly important.At present,the preparation and testing of flexible absorbing materials still have the following problems:1)The preparation efficiency of flexible absorbing materials is low,and the sample output is low,which is not conducive to industrial application;2)There are relatively few studies on the reliability of the electromagnetic parameter testing methods for flexible absorbing materials.In this paper,the method of electroless plating and suction filtration was used to prepare flexible absorbing materials with high dielectric loss and magnetic loss.The absorbing performance of flexible materials including coaxial method,waveguide method and arch method were compared.Finally,the test environment of the arch method is simulated,and the simulation results are compared with the experimental results.The main research contents are as follows:(1)A mixed cellulose flexible film(MCE,a mixture of nitrocellulose and cellulose acetate)with a three-dimensional network structure is used as a substrate,and Fe3Co7 nanoparticles are generated inside the substrate by electroless plating.The MCE film with a three-dimensional network structure provides sufficient nucleation space for the growth of Fe3Co7 nanoparticles,so that Fe3Co7 metal particles are evenly dispersed on the fiber surface to avoid agglomeration.Fe3Co7 alloy not only enhances the dielectric loss of the composite material including the conduction loss and interface loss,but also introduces magnetic loss.The effect of different reaction time(1 min,2 min,3 min)on the microwave absorption performance of the sample was studied experimentally.It was found that the sample obtained the best wave absorption performance after two minutes of reaction.At a matching thickness of 2 mm,the reflection loss reaches-35.8 dB,and the effective absorption bandwidth(EAB,RL<-10.0 dB corresponding frequency width)is 9.9 GHz(8.1 GHz-18.0 GHz).(2)Using organic/inorganic hybrid nanowires as precursors,nanorod Mo2C was prepared by annealing,and then FexNi(OH)y was grown on the surface of Mo2C by co-precipitation,and FeNi3 with magnetic loss was obtained by annealing at different temperatures.By suction filtration,FeNi3/Mo2C was combined with cellulose to prepare flexible,foldable and twistable flexible FeNi3/Mo2C absorbing paper.The wave absorbing properties of different ratios of FeNi3 and Mo2C and different annealed FeNi3/Mo2C and cellulose were studied.It was found that FeNi3:Mo2C is 1:3,and under the annealing condition of 500?,FeNi3/Mo2C absorbing paper can get the best Absorbing performance.At a thickness of 2.0 mm,the peak reflection loss is-51.50 dB,and the effective absorption bandwidth(EAB)reaches 5.1 GHz(11.7 GHz-16.8 GHz).In addition to using the coaxial method to test the absorbing properties of the samples,the performance of FeNi3/Mo2C absorbing paper is also compared using the waveguide method and the arch method,which proves the reliability of these three methods for testing flexible absorbing materials.COMSOL Multiphysics was used to simulate the arching test environment in the microwave darkroom environment,and further verify the experimental test results.