石墨烯包覆泡沫铜复合中间层钎焊碳/碳复合材料与铌的工艺与性能

Graphene-coated Cu foam interlayer for brazing C/C composite and Nb

针对石墨烯增强相在焊缝中难以分散均匀、结构完整性差、易团聚等问题.采用等离子增强化学气相沉积(PECVD)方法在泡沫铜表面原位制备高质量石墨烯,得到石墨烯增强泡沫铜复合中间层.使用该复合中间层钎焊碳/碳(C/C)复合材料与铌(Nb).采用Raman, SEM, HRTEM方法表征石墨烯以及钎焊接头的微观组织结构.结果表明,泡沫铜独特的多孔网络结构使其表面原位生长的高质量石墨烯在焊缝中均匀分布.同时,石墨烯优异的化学惰性保证了泡沫铜骨架的完整性,并协同石墨烯自身的低线膨胀系数充分发挥了缓解残余应力的作用,有效提高了接头的抗剪强度.

In order to solve the problems such as poor structural integrity,inhomogeneous dispersion and agglomeration of graphene in the brazing seam,PECVD process was utilized for in-situ preparation of high-quality graphene-coated Cu foam composite interlayer prior to being applied to braze C/C composite and Nb.Raman,SEM,HRTEM tests were carried out to characterize the prepared graphene and the brazed joints.The results show that graphene acquired even distribution in the brazing seam with the help of Cu foam,which owned interconnected porosity.Simultaneously,the excellent chemical inertia of graphene inhibited the collapse of Cu foam.Furthermore,based on the synergistic reinforcement effect of Cu foam,with good plastic deformation capacity,and graphene,with extremely low coefficient of linear expansion,the thermal residual stress in the joint has been effectively mitigated.The average shear strength of the joint was evidently improved.