Deposition Characteristics and Microstructure of a Ni60-Ni Composite Coating Produced by Supersonic Laser Deposition
J. H. Yao, L. J. Yang, B. Li, Q. L. Zhang and Z. H. Li
Supersonic laser deposition (SLD) is a novel coating method which combines the supersonic powder stream produced by cold spray with synchronous laser heating of the deposition zone. This article presents a study of using the SLD Ni60-Ni composite coatings on a #45 medium carbon steel substrate (AISI 1045). The microstructure of coatings and deposition characteristics were analyzed using scanning electron microscope (SEM) and energy dispersion spectrum (EDS), respectively. The results show that the SLD technique is able to achieve a dense crack-free coating, because deformed Ni particles are evenly distributed in the coatings, which benefit releasing residual stress developed in the composite coatings. The cross-section thickness of the Ni60-Ni composite coatings increased with enhanced laser power. It is also found that a Ni-rich layer is generated at the interface between the coating and substrate. This softer Ni-rich layer serves as a transition layer to accommodate the adhesion between the coating and substrate.
Keywords: Diode laser, AISI 1045 steel, Ni60-Ni composite, composite coating, supersonic laser deposition, laser irradiation, cold spray, thickness, microstructure