超蓬松掺杂石墨烯气凝胶复合材料的制备及其吸波性能

Preparation and microwave absorption properties of ultra-fluffy doped graphene aerogel composites

伴随着智能通信的迅猛发展,信息传输带来的电磁辐射问题愈发严峻,传统吸波材料存在衰减能力差、阻抗匹配难以调节等缺点,已不能满足实际应用。本文基于电磁损耗理论、多组分协同损耗和三维多孔气凝胶构筑的设计策略,应用水热合成法制备石墨烯气凝胶(GA),在溶剂热反应中添加由MnO_(2)包覆的镍锌铁氧体(NiZnFe_(2)O_(4)@MnO_(2))微球,与石墨烯介电材料复合,制备超蓬松磁掺杂石墨烯基复合气凝胶(NiZnFe_(2)O_(4)@MnO_(2)/GA)粉体。实验测试了复合气凝胶的吸波特性,分析了热处理温度和磁掺杂量对复合气凝胶吸波性能的影响机制及规律。结果可知,热处理温度为300℃、镍锌铁氧体掺杂量为15wt%时,复合气凝胶吸波效果最优。其匹配厚度为2.9 mm时,在频率为8.72 GHz处,最小反射损耗(RL_(min))达到了−47.27 dB,有效吸收带宽(EAB)为3.2 GHz,覆盖了X波段的大部分,且填料负载率仅为10wt%。本研究解决了材料阻抗匹配性差的问题,优化了吸波材料的介电损耗和磁损耗能力,满足了对吸波材料“薄、轻、宽、强”的应用要求。

With the rapid advancement of intelligent communication,the issue of electromagnetic radiation caused by information transmission is becoming increasingly severe.However,traditional microwave absorption materials have limitations such as poor attenuation ability and difficulties in impedance matching,which no longer meet practical applications.In this paper,graphene aerogel(GA)was prepared by hydrothermal synthesis based on the theory of electromagnetic loss,the design strategy of multi-component synergistic loss and the construction of threedimensional porous aerogel.To enhance its properties,we incorporated MnO_(2)-coated Ni-Zn ferrite(NiZnFe_(2)O_(4)@MnO_(2))microspheres with graphene dielectric material to prepare ultra-fluffy magnetically doped graphene-based composite aerogel(NiZnFe_(2)O_(4)@MnO_(2)/GA)powders.The impact of heat treatment temperature and magnetic doping on the wave absorption capability of the composite aerogel was analyzed.Our results demonstrate that at a heat treatment temperature of 300℃and a nickel-zinc ferrite doping amount of 15wt%,the composite aerogel exhibits optimal absorption performance.At a matching thickness of 2.9 mm,it achieves a minimum reflection loss(RL_(min))value of−47.27 dB at a frequency of 8.72 GHz,providing an effective absorption bandwidth(EAB)spanning 3.2 GHz covering most X-band frequencies while maintaining only a packing load rate of 10wt%.The problem of poor material impedance matching is solved,the dielectric loss and magnetic loss capacity of the absorbing materials are optimized.The application requirements of the wave absorbing material for"thin,light,wide and strong"are met.