Preparation And Microwave Absorbing Properties Of FeSip/PP Composite Fibres

As an effective way to solve the problems of electromagnetic pollution and interference,absorbing materials have a broad application prospect.Fibre composite absorbing materials are high-performance composite structure materials with good mechanical properties and high temperature resistance,which have great application potential.The composite fibres made of ferrosilicon alloy powders and thermoplastic resin can improve the material's magnetic anisotropy and absorbing property.In this paper,80wt%FeSiAlp/PP and 80wt%FeSiBYp/PP composite fibres with a diameter of 0.5 mm circular section and a diagonal length of 0.5 mm rhombic section were successfully prepared by extrusion drawing.The fibre strength is about 6?8 MPa.The reflection loss of materials is calculated by finite integral method.When the composite fibres are arranged in parallel in the epoxy matrix and the layer thickness is 6 mm,there are two excellent absorption peaks in the rhombic FeSiAlp/PP fibre boards in the frequency range of 0.3?20 GHz.The effective absorption bandwidth(Reflection loss(RL)<-10 dB)is 3.9 GHz,and the minimum RL is-18.43 dB at 4.5 GHz.Compared with the circular fibres,the rhombic fibre bandwidth increases by 1.8 GHz.The absorption bandwidth of rhombic FeSiBYp/PP fibre board is 18.5 GHz when RL is lower than-5 dB,which is 5 times of the circular fibre bandwidth.The effects of the thickness,fibre arrangement and spacing of the composite boards on its absorbing properties and the oblique incidence stability of the electromagnetic wave in the composites were studied.With the increase of the thickness of the composite boards,the frequency of the absorption peak moves to the low frequency range.When the fibres are arranged orthogonally,the RL of the FeSiBYp/PP circular fibre composite boards with the thickness of 2 mm is-34.0 dB at 15.6 GHz,and the effective absorption bandwidth is 6.6 GHz.The RL of the FeSiBYp/PP rhombic fibre composite boards with the thickness of 2 mm is-31.9 dB at 15.4 GHz,and the effective absorption bandwidth is 6.2 GHz.In parallel arrangement,the two cross-sections of FeSiAlp/PP and FeSiBYp/PP composite fibres modified resin matrix composites have better electromagnetic wave oblique incidence stability.