Fabrication of Copper Matrix Composites Reinforced with Carbon Nanotubes Using an Innovational Self-Reduction Molecular-Level-Mixing Method

Abstract

An innovational self-reduction molecular-level-mixing method was proposed as a simplified manufacturing technique for the production of carbon nanotube copper matrix composites (CNT/Cu). Copper matrix composites reinforced with varying amounts of (0.1, 0.3, 0.5 and 0.7 wt%) carbon nanotubes were fabricated by using this method combined with hot-pressing sintering technology. The surface structure and elemental distribution during the preparation of CNT/Cu mixing powder were investigated. The microstructure and comprehensive properties of the CNT/Cu composites were examined by metallography, mechanical and electrical conductivity tests. The results revealed that the CNT/Cu could be produced by a high temperature reaction at 900 degrees under vacuum, during which the carbon atoms in the carbon nanotubes reduced the divalent copper on the surface to zero-valent copper monomers. The decrease in the ratio of D and G peaks on the Raman spectra indicated that the defective spots on the carbon nanotubes were wrapped and covered by the copper atoms after a self-reduction reaction. The prepared CNT/Cu powders were uniformly embedded in the grain boundaries of the copper matrix materials and effectively hindered the tensile fracture. The overall characteristics of the CNT/Cu composites steadily increased with increasing CNT until the maximum at 0.7 wt%. The performance was achieved with a hardness of 86.1 HV, an electrical conductivity of 81.8% IACS, and tensile strength of 227.5 MPa.

Production and Characterization of Cu/CNT Nanocomposites

“…The increase observed for this ratio for ball milling may be due to the growth of defects in the structure of CNTs. Similar results were also obtained by Ya et al [4], who observed few defects promoted in the structure of the CNTs using sonication. However, defects increase with the cold rolling Furthermore, the ultrasonication process does not cause significant damage to the structure of the CNTs that would impair their strengthening effect.…”

“…The copper's outstanding electrical and thermal properties make this material extremely valuable for microelectronic devices. Nonetheless, its applicability is limited due to poor mechanical characteristics, such as hardness and wear resistance [4]. The use of CNTs as a reinforcement material for copper matrices can be a practical approach to improve their properties, such as compression and tensile strength [5], hardness [6,7], and also electrical and thermal conductivities [8].…”

“…The powder metallurgy process can be subdivided into four key steps, starting with the powder mixing and dispersion with the metal powder and reinforcement, followed by the pressing and the sintering of the samples [13]. In recent years, there has been an increase in published papers on Cu/CNT nanocomposites [4][5][6][7][8][14][15][16][17][18]. However, producing these nanocomposites by this process is still less reported than the Al/CNT and Ni/CNT nanocomposites, even though identifying strengthening mechanisms has been a topic of these works.…”

Recent Advances in Electrocatalytic Hydrogenation Reactions on Copper‐Based Catalysts

“…f) Adapted under the terms of the CC‐BY Creative Commons Attribution 4.0 International license (https://creativecommons.org/licenses/by/4.0). [ 39 ] Copyright 2022, The Authors, published by MDPI. g,h) Creating single‐atom sites.…”

“…Copyright 2019, The Authors, published by Springer Nature. f) Adapted under the terms of the CC-BY Creative Commons Attribution 4.0 International license (https://creativecommons.org/licenses/by/4.0) [39]. Copyright 2022, The Authors, published by MDPI.…”