叶正伟,赵奇志,王克军,李孝琼,杨健健.轻质磁性炭气凝胶的制备及电磁吸波性能研究[J].表面技术,2023,52(8):397-405.
YE Zheng-wei,ZHAO Qi-zhi,WANG Ke-jun,LI Xiao-qiong,YANG Jian-jian.Preparation and Electromagnetic Wave Absorbing Properties of Light Magnetic Carbon Aerogel[J].Surface Technology,2023,52(8):397-405 |
| 轻质磁性炭气凝胶的制备及电磁吸波性能研究 |
| Preparation and Electromagnetic Wave Absorbing Properties of Light Magnetic Carbon Aerogel |
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| DOI：10.16490/j.cnki.issn.1001-3660.2023.08.035 |
| 中文关键词: 炭气凝胶 四氧化三铁 粒径 电磁吸波材料 阻抗匹配 |
| 英文关键词:carbon aerogel ferroferric oxide particle size electromagnetic wave absorbing material impedance matching |
| 基金项目:装备发展基金 |
| 作者 | 单位 |
| 叶正伟 | 军事科学院防化研究院，武汉 430000 |
| 赵奇志 | 军事科学院防化研究院，武汉 430000 |
| 王克军 | 军事科学院防化研究院，武汉 430000 |
| 李孝琼 | 军事科学院防化研究院，武汉 430000 |
| 杨健健 | 军事科学院防化研究院，武汉 430000 |
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| Author | Institution |
| YE Zheng-wei | Chemical Defense Research Institute, Academy of Military Sciences, Wuhan 430000, China |
| ZHAO Qi-zhi | Chemical Defense Research Institute, Academy of Military Sciences, Wuhan 430000, China |
| WANG Ke-jun | Chemical Defense Research Institute, Academy of Military Sciences, Wuhan 430000, China |
| LI Xiao-qiong | Chemical Defense Research Institute, Academy of Military Sciences, Wuhan 430000, China |
| YANG Jian-jian | Chemical Defense Research Institute, Academy of Military Sciences, Wuhan 430000, China |
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| 中文摘要: |
| 目的 提高炭气凝胶材料电磁吸波性能。方法 以氢氧化钠或氨水为共沉淀剂制备不同尺寸的Fe3O4颗粒，并加入间苯二酚-甲醛溶液的预聚物中，充分搅拌后快速凝胶，经老化、超临界干燥、碳化等工艺制备Fe3O4/炭气凝胶复合材料。利用SEM、TEM、激光粒度分析仪、比表面及微孔分析仪、振动样品磁强计对Fe3O4及复合材料的微观结构和静磁性能进行表征，并对复合材料的吸波性能进行分析。结果 Fe3O4/炭气凝胶复合材料具有丰富的三维网络结构，Fe3O4颗粒在炭气凝胶中呈离散性分布。Fe3O4颗粒粒径越小，Fe3O4/CA的饱和磁化强度越大，75 nm-Fe3O4/CA的饱和磁化强度最大，达到29.26 emu.g–1;当Fe3O4粒径为75 nm时，复合材料在厚度为2.1 mm时的最小反射损耗值可达–52.43 dB;当Fe3O4粒径为120 nm时，复合材料在厚度为2.5 mm时的有效吸收带宽高达6.98 GHz。结论 Fe3O4纳米颗粒粒径对复合材料介电损耗能力和阻抗匹配有显著影响，进而影响复合材料的吸波性能。大粒径的Fe3O4颗粒会破坏炭气凝胶的三维导电网络结构，从而降低复合材料的介电损耗能力。小粒径的Fe3O4颗粒可有效改善复合材料的阻抗匹配性能。 |
| 英文摘要: |
| With the rapid spread of wireless communication devices using electromagnetic waves in the range around GHz, several problems such as electromagnetic interference and information leakage have emerged and need to be solved. Microwave absorption materials can absorb electromagnetic waves effectively and convert electromagnetic energy into thermal energy, thus are highly demanded to eliminate adverse electromagnetic waves effectively in electronic safety, and national defense security. Porous carbon materials are always employed to absorb microwave energy due to the very large surface area and great potential for further functionalization. In this paper, ferrite/carbon aerogel composites were fabricated to endow the carbon aerogel magnetic property and also lower density of composites. First, Fe3O4 particles of different sizes were prepared by a simple co-precipitation (using sodium hydroxide or ammonia as co-precipitator) through controlling the Fe ions concentration of the reaction system. Then the aqueous solution of Fe3O4 modified by CTAB was prepared and added to the resorcinol- formaldehyde sol. After sufficient mixing, the solution was left to gel by elevating the temperature and supercritical drying subsequently. The final magnetic carbon aerogel composites were obtained by pyrolysis of the organic polymeric aerogel at 690 ℃. SEM (FEI Company Sirion200) and TEM (Japan Electronics Corporation JEM-1400Plus) were used to characterize the Fe3O4 particle size and microstructure of the composites. A laser particle size analyzer (Malvern Company Zetasizer Nano ZSP) was used to characterize the particle size and distribution of the Fe3O4 particles. The surface area and pore size of the magnetic carbon aerogels were characterized by a specific surface and micropore analyzer (BSD-PM). The static magnetic properties of the materials were characterized by a vibrating sample magnetometer (Lake Shore model 7 404G). The complex permeability and permittivity of materials were measured with a N5 230A vector network analyzer by coaxial wire method over the frequency range of 2~18 GHz. The results showed that, Fe3O4/carbon aerogel composites had rich three-dimensional network structure, and carbon aerogel provided a large contact surface for individual and uniform dispersion of well-adhered Fe3O4 particles on it. Fe3O4/CA had typical ferromagnetic properties, and the saturation magnetization of Fe3O4/CA increased as the Fe3O4 particle size decreased. The saturation magnetization of 75 nm-Fe3O4/CA was the largest, reaching 29.26 emu.g–1. When the size of incorporated Fe3O4 particle was 330 nm, the minimum reflection loss value of the composite was only –10.61 dB, and the microwave absorption performance was poor. When the particle size of Fe3O4 was 75 nm and the thickness of the composite was 2.1 mm, the minimum reflection loss value could reach –52.43 dB at 17.15 GHz. When the particle size of Fe3O4 was 120 nm, the effective absorption bandwidth of the composite at the thickness of 2.5 mm could reach 6.98 GHz (10.97~17.95 GHz). The mechanism of the microwave absorption of Fe3O4/carbon aerogel composites could be concluded by following:firstly, carbon aerogel acting as perfect 3D substrate provides a large specific surface area for the dispersion of Fe3O4 particles, which gives rise to dielectric loss and magnetic loss respectively and makes the hybrid perform better microwave absorption properties. Secondly, the microwave absorption capability can be attributed to a strong conductivity loss, and it can be optimized by phase component and microstructure with an interfacial polarization capability. When the particle size of Fe3O4 is small, the complex dielectric constant of the composites is relatively large. However, when the particle size of Fe3O4 is large, the three-dimensional conductive network structure of carbon aerogel would be destroyed by the large Fe3O4 particles, which will reduce the dielectric loss ability of the composite. In addition, the porous structure could prolong the propagation paths for electromagnetic wave reflection and scattering in the composites. |
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