合金化Cu改善石墨烯润湿性及其复合材料性能研究

Graphene reinforced copper matrix composites show attractive prospects in electrical contact materials, electronic packaging materials and other fields for its excellent mechanical, high thermal conductivity and high wear resistance. However the poor dispersion of graphene in copper matrix composite hinder enhancement of its properties, which limit the synthesis and application of graphene/Cu composites. For the higher solubility of C in Ni particle and the hybridization between π bond of C and dz2 orbit of Ni have a strong chemical absorption. This proposal is based on the synthesis of CuNi alloy to increase the surface binding energy of Cu and graphene, which can improve the dispersion of graphene in copper matrix. The influence of reactant, reaction temperature and time will be investigated for the controllable synthesis of CuNi alloy. During the thermal reduction process of graphene oxide, the reduction and particle growth occur synchronously. A novel complex structure of CuNi alloy grown in situ on the surface of graphene will be designed and fabricated, so as to avoid graphene agglomeration in Cu matrix. The graphene/Cu composites were sintered by SPS using these powders. Finally, the relationship of composition-structure-properties will be proposed and this work will supply a new research approach on design graphene reinforced composites.

石墨烯增强铜基复合材料具有高强、高导、高耐磨等优点，在电接触材料、电子封装材料等领域，具有诱人的发展前景。但由于石墨烯在铜基体中的分散性较差，增强效果不明显，限制了石墨烯/铜基复合材料的制备和应用。本项目拟通过CuNi合金，利用Ni本身碳溶解度高，碳的π键和Ni的dz2轨道之间的杂化具有强烈的化学吸附作用，提升Cu与石墨烯的表面结合能，增强石墨烯在Cu中的分散性。系统研究反应物、反应条件对CuNi合金合成的影响规律，实现对CuNi合金组成、结构、形貌的精确调控；结合氧化石墨烯热还原过程，实现还原与颗粒生长同步发生，构筑石墨烯表面原位生长CuNi合金复杂结构，避免石墨烯团聚。采用SPS烧结获得复合材料，揭示“组成-结构-性能”之间的关系，为研究石墨烯复合材料提供新的研究思路。

本项目围绕高强度高导电铜基纳米材料的可控制备问题，通过控制材料成核和生长过程，获得了系列组成、尺寸、形貌可控的纳米铜基复合材料。采用一步法全液相前驱体合成技术，设计了连续化合成反应装置，使纳米材料能够实现连续化生产，减少了传统间隙釜反应传热、传质不均匀对纳米材料成核和生长过程的影响，避免了纳米材料易团聚、难分散的问题，获得了组成、形貌、粒径可控的单分散纳米铜粉；以纳米铜粉为主要原材料，利用表面改性，获得了分散性好、抗沉降性良好的导电墨水，通过合理粒径搭配，利用纳米化后小颗粒熔点低的优点，采用低温烧结，获得的纳米铜膜电阻率为38μΩ·cm；采用简单的热注射方法，通过控制注射顺序的不同，研究了材料成核-生长过程对于材料组成、形貌、性质的影响，获得了一系列复杂组成和结构的纳米铜基复合材料，为后续改善石墨烯与铜的结合力的问题提供了方法；同时将纳米材料的可控合成扩展到锂离子电池正极材料的制备中，获得了碳材料限域包覆的FeF3电池材料，解决了FeF3材料导电性差、充放电过程中因转化反应造成FeF3材料衰减严重的问题，获得了倍率性能较好的正极材料。