Pretreatment and copper plating of carbon nanotubes by electroless deposition

The work aims to improve the wettability of CNTs and the interfacial bonding force between CNTs and metal matrix by plating a uniformly distributed copper coating on the surface of CNTs through electroless deposition, so as to realize uniform dispersion of CNTs in the metal matrix, and provide an approach to prepare excellent metal matrix composites. Firstly, CNTs were pretreated, including purification, oxidation, sensitization and activation. Then, electroless copper plating was carried out on the surface so as to obtain uniformly distributed copper plating on the surface of CNTs. The microstructures of CNTs in different states were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Raman spectroscopy (Raman). The copper plating on the CNTs could be realized after pretreatment. Meanwhile, the growth of the copper plating on surface of CNTs was not a continuous and stable process. First, it nucleated and grew at a higher activation level, then grew horizontally, and eventually covered the whole surface of CNTs. The optimum preparation conditions of electroless deposition were obtained through the experiment. The concentration of CuSO4·5H2O was 18 g/L and the reaction time was 15 min. Thus, a layer of uniform copper plating was successfully grown on the CNTs, and the plating thickness of different parts on single CNTs was basically the same, so the average thickness of copper plating was 25 nm. After pretreatment of CNTs, oxygen-containing functional groups are formed on the surface. The copper plating process removes most of the functional groups on the surface of CNTs, and a uniform nano-sized copper plating is obtained on the surface of CNTs, which improves the wettability of CNTs in metal matrix and provides an important way for CNTs to be applied to metal matrix composites. © 2019, Chongqing Wujiu Periodicals Press. All rights reserved.