Deposition of High-Density Carbon Nanotube-Containing Nickel-Based Composite Films by Low-Pressure Cold Spray

Abstract

Carbon nanotubes (CNTs) have a large specific surface area and, thus, are expected to have applications as electrodes, e.g., in fuel cells. A CNT-containing composite metal film with high electrode performance could be realized by implementing a large number of CNTs on the film. However, a composite film with a high density of CNTs has not yet been obtained. In the thermal spray field, including cold spray, metal–CNT composite films with more than 20 wt% of carbon nanotubes has not yet been deposited. In this study, high-density CNT-containing metal-based composite films were deposited onto an aluminum substrate by low-pressure cold spray from electroless nickel-plated CNT particles. The electroless nickel plating process caused slight structural damage to the CNTs, whereas the cold spray process did not cause any significant structural damage to the CNTs. Two phases were observed in the films: a CNT-rich layer and a nickel-rich layer. However, the CNTs maintained sufficient adhesive strength to remain attached to the bottom nickel phase. Composite films with at least 65 wt% CNT were produced with our method.