Two-dimensional distribution of carbon nanotubes in copper flake powders

Abstract

We report an approach of flake powder metallurgy to the uniform, two-dimensional (2D) distribution of carbon nanotubes (CNTs) in Cu flake powders. It consists of the preparation of Cu flakes by ball milling in an imidazoline derivative (IMD) aqueous solution, surface modification of Cu flakes with polyvinyl alcohol (PVA) hydrosol and adsorption of CNTs from a CNT aqueous suspension. During ball milling, a hydrophobic monolayer of IMD is adsorbed on the surface of the Cu flakes, on top of which a hydrophilic PVA film is adsorbed subsequently. This PVA film could further interact with the carboxyl-group functionalized CNTs and act to lock the CNTs onto the surfaces of the Cu flakes. The CNT volume fraction is controlled easily by adjusting the concentration/volume of CNT aqueous suspension and Cu flake thickness. The as-prepared CNT/Cu composite flakes will serve as suitable building blocks for the self-assembly of CNT/Cu laminated composites that enable the full potential of 2D distributed CNTs to achieve high thermal conductivity.

Processing of copper–carbon nanotube composites by vacuum hot pressing technique

“…It was shown that the presence of oxygen at the Cu-CNT interface resulted in good load transfer affecting high degree of strengthening [25] in compacts obtained by spark plasma sintering. Another technique used for improving dispersion is by attaching CNTs to Cu flakes produced by ball milling by means of a binder [26]. Roll bonding has also been used for dispersing CNTs between thin Cu foils [27].…”

Microstructure and Properties of a Graphene Reinforced Cu–Cr–Mg Composite

“…Compared with a spherical powder, the two-dimensional structures of the flake powder and of graphene are very similar, which can effectively increase the contact area between the powder and graphene. This will not only enable improved support for the GNPs but also improve the bond strength between the alloy matrix and the GNPs [ 4 , 12 , 14 , 15 ]. As can be seen in Figure 2 , due to the high rotation rate and high ball-to-powder ratio, the repeated compression impact force exerted by the ball on the powder during the ball-milling process is large, and the initially spherical Cu–Cr–Mg alloy powder particles have been flattened.…”

Progress of Flake Powder Metallurgy Research

“…Nevertheless, these solutions require energy and time consumption which is incompatible with industrial production. Therefore, pre-dispersion optimized methods are fundamental in this direction [34,52,69,82]. It seems that FPM results in the best route, with optimal control of the process and high mechanical properties, even if there is still space for further improvement.…”