Preparation Of Fe₃Si/PPy Composite Material And Research On Its Absorbing Properties

Electromagnetic waves pollute the environment,endanger people's health,disrupt signal transmission,and disrupt the normal operation of large equipment.Therefore,absorbing materials are widely used for the purpose of absorbing and attenuating electromagnetic waves,protecting the environment and people's health.The basic requirements for excellent performance of absorbing materials are strong absorption,broadband,light weight,thin thickness,high temperature resistance,etc.In this paper,first principles are used to predict the absorbing properties of Fe₃Si/PPy composites.Secondly,using a combination of theory and experiment to study the absorbing properties of Fe₃Si/PPy composites,and exploring the influence of different contents of polypyrrole,ammonium persulfate,and hydrochloric acid on the absorbing properties of Fe₃Si/PPy,the results are as follows.(1)The first-principles calculation results show that the imaginary part of the dielectric constant of Fe₃Si/PPy is greater than that of Fe₃Si.The maximum absorption coefficient of Fe₃Si is greater than that of Fe₃Si/PPy,and the absorption coefficients of both materials increase first and then decrease.However,the variation range of the absorption coefficient,the maximum reflection coefficient and the maximum extinction coefficient of Fe₃Si/PPy are larger than those of Fe₃Si.The maximum reflection coefficients of Fe₃Si/PPy and Fe₃Si are 0.81 and 0.91,respectively.In terms of loss function and refractive index,Fe₃Si/PPy is highly practical.(2)Fe₃Si,Fe₃O₄and polypyrrole form a composite material.The calculation results show that the real part and static dielectric constant of Fe₃Si/PPy are the largest.The Fe₃Si/PPy absorption coefficient has a wide variation range,a large absorption coefficient,a wide energy absorption range,and a wide coverage energy range.Fe₃Si/PPy has a low reflection coefficient and a wide refractive index range.The loss function value of Fe₃Si/PPy is greater than that of Fe₃O₄/PPy.However,the loss range of Fe₃Si/PPy is larger.Therefore,the absorbing performance of Fe₃Si/PPy is better than Fe₃O₄/PPy.(3)Fe₃Si magnetic powder was prepared by mechanical alloying-vacuum annealing,and then Fe₃Si/PPy composite was prepared by one-pot method.The content of polypyrrole,ammonium persulfate and hydrochloric acid was changed,and the influence of different parameters and contents on the absorbing performance of Fe₃Si/PPy was discussed.The results show that when the content of polypyrrole is1.0g,the reflection loss is-35.176 d B and the thickness is 4.5mm;when the content of APS is 1.4g,the maximum reflection loss is-34.59 d B when the thickness is 5mm.when the HCl content is 50ml,The reflection loss is-25.828d B,and the thickness is4mm.(4)Due to the introduction of polypyrrole,electron transfer and interface effects occur between Fe₃Si and PPy,so Fe₃Si/PPy has better microwave absorbing performance than Fe₃Si single component.There is a synergistic effect between magnetic Fe3Si and polypyrrole.There are a large number of dipoles between the influence of dielectric loss(strong interface)of Fe₃Si/PPy polarization and magnetic loss(eddy current loss,magnetic resonance and exchange resonance of natural iron).Polymer polypyrrole causes dielectric loss and conduction loss,and magnetic loss between Fe₃Si and PPy that causes Fe₃Si interface polarization.Fe₃Si/PPy has more irregular Debye semicircles than Fe₃Si,indicating that Fe₃Si/PPy has stronger dielectric polarization relaxation than Fe₃Si.In the first-principles calculations,Fe₃Si/PPy has magnetic and dielectric properties,and the experimental conclusions are in good agreement with the theoretical calculations.