碳包覆金属纳米粒子核壳结构原位组装构筑泡沫炭材料及其电磁特性研究

How to design and fabricate cost-efficient, light-weight and effective electromagnetic absorption materials remains a big challenge, though these fuctional materials are of great application potential for electromagnetic pollution control and for wave adsorbing i.e. stealth materials. In this project, we propose to develop a novel technique to make functional carbon foams in which the metal nanoparticles are highly dispersed inside the ligaments by coupling the template method with in situ catalytic graphitization involved in the co-carbonization. The metal nanoparticles dispersed inside the ligaments of carbon foam are in situ formed and coated by graphitic carbon shells at elevated heat treatment temperatures. The macrostructure of the as-made carbon foams, nanotexture and microstructure of the amorphous or graphitic carbon shells, the shape and phase of the metal nanoparticles as well as the interface properties between each component will be studied in detail. Their effects on the microwave absorption properties of the as-made monolithic carbon foam composites will be addressed. The fabrication process will be optimized in terms of the template macrostructure, the property of precursors and the technological parameters. This work will yield more information about the formation and distribution of metal nanoparticles inside the carbon matrix of the monolithic carbon foam composites as well as the interaction between the metal nanoparticles and the amorphous carbon during the co-carbonization. These efforts will shed a new light on the catalytic graphitization process and on the novel approach to the fabrication of stealth materials with tuned structure and properties. It is also help understand the intrinsic property and syntrgistic effect of each component. The project will finally result in a proven technique for the design and fabrication of high performance electromagnetic absorption materials.

廉价轻质的高性能吸波材料在军事隐身及电磁污染控制等领域均有重要应用，其设计与可控制备是国内外关注的前沿课题。本项目提出基于模板复制耦合共炭化技术，将金属纳米粒子均匀分散于泡沫炭韧带内部，经热处理引发催化石墨化反应原位生成石墨化碳包覆金属纳米粒子，进而原位组装构筑泡沫炭材料的基体韧带，形成三维空间连续导电网络，创造性实现纳米尺度碳包金属粒子材料和宏观尺度泡沫炭材料的有机融合。将研究揭示模板宏观结构、原料组成及合成工艺参数对功能泡沫炭之结构和性能的影响规律，研究建立调控泡沫炭宏观结构、非石墨化炭基体和石墨化碳壳的微观结构及碳包覆金属纳米粒子性质的技术策略，诠释共炭化过程中金属纳米粒子在炭基体内的形成机制和分布规律特征及金属与炭基体间耦合作用机制，研究建立构筑具有优异电磁特性的新型整体式吸波材料的新技术方法。课题的实施将丰富吸波材料和催化石墨化的内涵，为整体式高性能吸波材料的创制提供新思路。

随着电磁污染的加剧及现代军事的发展，亟需开发高性能结构型吸波材料以满足民用及军事的需求。如何设计并合成价格低廉、轻质并具有优异吸波性能的新材料是本领域的核心问题之一。本项目开发了基于模板复制耦合共炭化技术，将金属纳米粒子均匀分散于泡沫炭韧带内部，经热处理引发催化石墨化反应原位生成石墨化碳包覆金属纳米粒子组装构筑泡沫炭材料的新技术。碳包金属纳米粒子在泡沫炭基体内形成三维空间连续导电网络，创造性实现纳米尺度碳包金属粒子材料和宏观尺度泡沫炭材料的有机融合。研究揭示了模板宏观结构、原料组成及合成工艺参数对功能泡沫炭之结构和性能的影响规律，建立了调控泡沫炭宏观结构、非石墨化炭基体和石墨化碳壳的微观结构及碳包覆金属纳米粒子性质的技术策略，诠释了共炭化过程中金属纳米粒子在炭基体内的形成机制和分布规律特征及金属与炭基体间耦合作用机制，研究建立了构筑具有优异电磁特性的新型整体式吸波材料的新技术方法。主要研究成果包括：.（1）以沥青烯为碳源、聚氨酯泡沫为模板、硝酸镍为金属盐制备由碳包镍纳米核壳材料组装的泡沫炭复合材料。碳包金属纳米粒子分散均匀，粒径约为50 nm。通过调节炭化温度和镍含量等调控泡沫炭的电磁参数及吸波能力。最优材料在14.3 GHz时，最大吸收达到-16 dB，有效吸收频宽超过5 GHz，经进一步复合环氧树脂层后，样品的最大吸波损耗提升至 -18.8 dB，有效吸收频宽超过8 GHz。.（2）以煤液化残渣（CLR）为碳源采用模板法制备泡沫炭吸波材料。泡沫炭保持模板的三维孔泡结构，孔泡直径约为400-600μm。CLR中富集的催化剂磁黄铁矿等组分结合添加的镍物种转变为高分散磁损耗粒子。由低石墨化碳基体、高石墨化壳层以及高分散磁损耗纳米粒子组装合成的三维多孔整体吸波材料在适宜的阻抗匹配、高介电损耗、高磁损耗以及多重界面引发的界面极化和弛豫损耗的共同作用下展现出优异的吸波性能。材料有效吸收频宽达到9.5 GHz，最大吸波损耗达到-23.3dB。.课题的实施丰富了吸波材料和催化石墨化的内涵，为整体式高性能吸波材料的创制提供了新思路。项目执行期间，发表论文5篇，其中SCI收录论文2篇；申请专利5项；参加国际国内学术会议3 次；培养硕士研究生2名。