Improving strength and high electrical conductivity of multi-walled carbon nanotubes/copper composites fabricated by electrodeposition and powder metallurgy

Abstract Electrodeposition was used to successfully fabricate MWCNTs/Cu composite powders which were further consolidated by hot pressing followed by cold rolling. A stable MWCNTs suspension was prepared prior to electrodeposition through centrifuging a functional MWCNTs solution to improve dispersion of MWCNTs in acid copper sulfate electrolyte and strong bonding of Cu ions with MWCNTs. The effects of MWCNTs concentration in electrolyte on MWCNTs content and microstructure of powders were investigated. Moreover, scraping powders treatment during electrodeposition significantly improved uniform distribution of MWCNTs and produced network architecture of MWCNTs in Cu matrix. The MWCNTs/Cu composites were further treated by cold rolling leading to directional alignment of MWCNTs in the matrix. Due to uniform distribution of MWCNTs as well as strong interfacial bonding strength between the reinforcements and Cu matrix, the resulting composites exhibit the increased tensile strength (451.57 MPa) and high electrical conductivity, only slightly lower than that of electrolytic pure Cu (99.92% IACS). Both bridge linking efficiency of network architecture and directional alignment of MWCNTs in the matrix not only increase effective load-transfer but also provide new pathways for electron transport, thus are further contributed to high mechanical and electrical properties of MWCNTs/Cu composites.