用化学还原液相悬浮氧化石墨法制备了石墨烯, 经亲水处理后, 利用化学镀镍法在其表面镀上均匀镍颗粒层. 采用SEM、EDX、振动样品磁强计等对样品的形貌、元素成分与磁性质进行了表征, 并用矢量网络分析仪测试了样品在2~18GHz频带内的复磁导率和复介电常数, 利用计算机模拟出不同厚度材料的微波衰减性能. 结果表明, 材料的微波吸收峰随着样品厚度的增加向低频移动, 材料的电磁损耗机制主要为电损耗, 未镀镍石墨烯的吸波层厚度为1mm时, 在7GHz左右最大衰减值?为?6.5dB, 镀镍石墨烯的吸波层厚度为1.5mm时, 在约12GHz时最大值为-16.5dB, 并且在频带9.5~14.6 GHz的范围内达到-10dB的吸收.
Graphene sheets were prepared by using chemical reduction of a colloidal suspension of graphene oxide sheets in water. After hydrophilic treatment and chemical plating, a layer of nickel particles was uniformly coated on the surfaces of the graphene sheets. The morphologies of the pure graphene (GF) and Ni-coated graphene (NGF), nickel element content on the graphene surface and magnetic properties of the NGF were examined by SEM, EDX and VSM, respectively. The complex relative permittivity and permeability of the NGF absorber were measured by using a microwave network analyzer in the frequency range of 2-18 GHz. The reflection loss curves of the GF and NGF were calculated using computer simulation technique. It is found that in the frequency range of 2-18 GHz, with the increase of the matching thickness, the maximum absorbing peaks of the GF and NGF shift to lower frequency region, so GF and NGF are dielectric loss microwave absorption materials. When the matching thickness is 1 mm, the maximum absorption peak of the GF is -6.5dB at about 7GHz. When the matching thickness is 1.5 mm, the maximum absorption peak of the NGF is -16.5dB at 9.25 GHz and the frequency region in which the maximum reflection loss is more than -10.0 dB is 9.5-14.6 GHz.
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