镀镍中间相沥青基碳纤维的吸波性能

为了改善中间相沥青基碳纤维的磁性能和吸波性能,通过化学镀工艺在中间相沥青基碳纤维表面均匀包覆了金属镍,研究了镀镍中间相沥青基碳纤维的磁性能和微波吸收性能。以镀镍中间相沥青基碳纤维作为吸收剂,环氧树脂为基体制备了单层吸波涂层,涂层的厚度为1.02 mm时,吸波涂层在15.4~18 GHz反射率R小于-10 dB,最大吸收峰在18 GHz,反射率R为-20.74 dB。探讨了镀镍中间相沥青基碳纤维的吸收机理,在含镀镍中间相沥青基碳纤维的吸波涂层中,镀镍中间相沥青基碳纤维作为偶极子在电磁场的作用下,会产生耗散电流,在周围基体作用下,耗散电流被衰减,从而电磁波能量转换为其它形式的能量,主要为热能,这是镀镍中间相沥青基碳纤维偶极子吸波涂层的主要吸波机理。

Microwave Absorbing Property of Nickel-coated Mesophase Pitch-based Carbon Fibers

In order to improve the magnetic and microwave absorbing properties,the nickel coatings on the mesophase pitch-based carbon fibers were deposited by electroless plating technique.The magnetic and microwave absorbing properties of the nickel-coated mesophase pitch-based carbon fibers were investigated.The single-layer microwave absorbing coatings employing absorbent of nickel-coated carbon fibers with epoxy resin as matrix have been prepared.The reflection loss of the single-layer microwave absorbing coating containing nickel-coated carbon fiber absorber with a thickness of 1.02 mm is below-10 dB(90% absorption) in the range of 15.4~18 GHz,and the minimum value is-20.74 dB at 18 GHz.The nickel-coated mesophase pitch-based carbon fibers were used as dipoles to absorb the microwave in the composites.In the microwave absorbing material with the electromagnetic lossy substance and dipoles,the dipoles as multiple electric doublets can generate inductive currents in the electromagnetic field.The induced currents then cause energy dissipation as dispersion currents.In the lossy medium,the electromagnetic energy is changed into thermal energy.This is the main mechanism of microwave attenuation by nickel-coated mesophase pitch-based carbon fibers.