The preparation and electromagnetic absorption performance of carbonyl iron-graphene composites
The composite of graphene and carbonyl iron powder not only breaks through the snooker limit of iron powder as an absorber,but also improves its electromagnetic impedance matching characteristics to some extent.In this paper,graphene and lamellar carbonyl iron powder were lamellarly composited using aminophosphoric acid as a linker,and carbonyl iron powder/graphene composite wave-absorbing powders with dielectric frequency dispersive properties were obtained by a one-step method.The effects of different synthesis conditions(content of modified graphene,reaction temperature,and content of aminophosphoric acid)on the electromagnetic parameters and reflective losses of carbonyl iron powder/graphene composite wave-absorbing materials were investigated.The results show that due to the introduction of graphene,the electromagnetic impedance matching performance of the composite powders is significantly enhanced,exhibiting good wave absorption performance.When the graphene oxide(GO)content is 1%(mass fraction),the minimum reflection loss value(RLmin)of the composite powders(thickness of 3.7 mm)at 4.23 GHz is-43.90 dB,and the effective absorption bandwidth(RL≤-10dB)is10.4 GHz(3.63-14.03 GHz).When the reaction temperature is 80℃,the composite powder shows good wave absorption efficiency.When the thickness is 4.5 mm,the minimum reflection loss value of the composite powder at 2.3 GHz reaches-42.92 dB,and the effective absorption bandwidth(RL≤-10 dB)is 6.7 GHz(2.0-8.7 GHz).The addition of APSA results in a significant increase in the conductivity of the composite powders,while the dielectric loss is enhanced.When 0.5%(mass fraction)APSA is added,the composite powder has the strongest conductivity,stable dielectric loss performance,and good absorption modification effect.The minimum reflection loss is-42.92 dB,and its corresponding effective absorption bandwidth(RL≤-10 dB)is 6.7 GHz(2.1-8.8 GHz)within 2-18 GHz.
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