Enhancing Interfacial Bonding and Tensile Strength in CNT-Cu Composites by a Synergetic Method of Spraying Pyrolysis and Flake Powder Metallurgy

Carbon nanotube (CNT)-reinforced metal matrix composites (MMCs) face the problems of dispersion and interfacial wetting with regard to the matrix. A synergetic method of spray pyrolysis (SP) and flake powder metallurgy (FPM) is used in this paper to improve the dispersibility and interfacial bonding of CNTs in a Cu matrix. The results of the interface characterization show interface oxygen atoms (in the form of Cu2O) and a high density of dislocation areas, which is beneficial for interfacial bonding. The tensile results show that the tensile strength of the SP-CNT-Cu composites is much higher than that of the CNT-Cu composites when the mass fraction of the CNTs does not reach the critical value. This can be explained by the nanoparticles which are found on the surface of the CNTs during the SP process. These nanoparticles not only increase the tensile strength of the SP-CNT-Cu composites but also improve the dispersion of the CNTs in the Cu matrix. Thereby, uniform dispersion of CNTs, interfacial bonding between CNTs and the Cu matrix, and the enhancement of tensile strength are achieved simultaneously by the synergetic method.