原位生长三维连续石墨烯增强高强高导铜基复合材料及其强化机制

The key to improve the strength and electrical conductivity of the copper matrix composites is to control the uniform dispersion of nano reinforcements and obtain a good interface with the matrix. This study proposed using nanoporous copper as template, in-situ growth of three-dimensional interconnection graphene on copper matrix pore surface by CVD method, and obtained the bulk composite material which has Cu / Graphene / Cu sandwich structure by filling the three-dimensional hole with the reduced copper salt. In situ growth method can guarantee the dispersibility and uniformity of grapheme reinforcements, and refilling process by chemical method is beneficial to maintain the three-dimensional structure of grapheme which is induced by Cu template, and to ensure a good interface bonding. In the two phase "parallel" conductive path constructed by three-dimensional network of graphene and continuous copper matrix, three-dimensional graphene can play the most important role, and it is expected to obtain both the high strength and high electrical conductivity of the composite material. This project focuses on the growth mechanism of graphene in nanopores; analysis of influence factors of the reaction parameters on the morphology, crystal structure and interface of porous copper, three-dimensional graphene network and the composite structure; and clarifies the fundamental basis of improving the strength and electrical conductivity of three dimensional graphene and “sandwich” structure.

纳米增强体的分散均匀性及其与基体的良好界面是提高铜基复合材料的强度及导电性能的关键。本课题提出以去合金化法得到的纳米多孔铜为模板，采用CVD法在铜基体内部孔洞表面原位生长石墨烯得到三维网络增强体，随之通过铜盐浸渍还原填充三维孔洞，得到铜/石墨烯/铜三明治结构，最后压制成型得到致密的块体结构。原位生长保证石墨烯的分散性和均匀性，模板诱导得到纳米尺度的石墨烯三维网络结构，化学法再填充有利于保持石墨烯的结构，同时保证良好的界面结合。三维网络石墨烯及连续的铜基体构成了两相“并联”的导电通路，完整的石墨烯结构能够发挥其最大的增强作用，有望得到兼具强度与导电性的复合材料。本项目重点研究纳米孔洞内石墨烯的生长机制；分析反应参数对多孔铜、三维石墨烯网络及复合材料结构的形态、晶体结构及界面的影响因素；阐明三维石墨烯结构及铜/石墨烯/铜三明治结构对提高复合材料强度及导电性的根本依据。

本项目针对三维连续石墨烯网络增强铜基复合材料的制备研究完成了以下几部分工作。1)采用脱合金方法制备具有纳米孔洞的铜基体，探究制备稳定纳米多孔铜的铜/锰二元合金成分以及合适的腐蚀介质；对铜粉采用直接冷压方法成型获得微米级别孔洞的多孔铜基体；2)通过 CVD 法在铜基体内部的三维连续孔洞表面原位生长石墨烯，能够达到三维石墨烯的连续分布，研究碳源气体及载气气氛等生长参数（如裂解温度、气氛流量等）对石墨烯生长质量的影响，并初步了解生长环境对石墨烯可能产生缺陷的影响，探究了纳米孔洞内铜基体表面石墨烯的原位生长机制，分析反应参数对多孔铜、三维石墨烯网络及复合材料结构的形态、晶体结构及界面的影响；3)通过多种冷热加工手段获得致密的块体复合材料，并总结了烧结工艺、冷轧加工及退火、热压加工等工艺参数对石墨烯增强体在复合材料强化效果发挥的影响；4)初步分析了多孔铜内部原位生长石墨烯与铜基体之间的结合情况，分析和阐明三维石墨烯结构增强体对提高复合材料强度及导电性、耐磨性的依据。项目的研究成果对石墨烯增强铜基复合材料在民用机械材料领域可靠性应用的探索提供理论支撑和实践支持，并有望在导电耐磨铜基材料领域实现应用。基于本项目支撑，共发表论文5篇其中SCI检索3篇，申请专利4项，参加国内学术会议1次，培养硕士研究生4名。