Beneficial Effects of Synchronous Laser Irradiation on the Characteristics of Cold-Sprayed Copper Coatings

Abstract

Cold spray (CS) is an emerging materials deposition technique in which metallic particles are accelerated to a high velocity in a supersonic gas flow and then impinged onto a substrate to form a coating at a temperature well below the melting point of sprayed materials. The coating microstructure and properties are greatly influenced by particle preheating and substrate softening. This article presents a study of CS process of copper powder, with assistance of synchronous laser irradiation. The influence of synchronous laser irradiation on the Cu coating characteristics was investigated. The results show that the coating surface with laser irradiation is smoother than that without laser irradiation. The peak coating thickness is increased by about 70% as synchronous laser irradiation is employed, indicating an improvement in deposition efficiency. It is also found that with synchronous laser irradiation the coating is denser and the coating-substrate interfacial bonding is better as compared with that without laser irradiation. Moreover, the EDS and XRD analyses find Cu oxidation occurrence in the SLD coating, but the oxide is trivial. The aforementioned improvements on the coating largely arise from particle preheating and substrate softening by synchronous laser irradiation in the CS process.