Cold spray deposition of Inconel 718 in comparison with atmospheric plasma spray deposition

Inconel 718 is a Ni-based superalloy which has been widely used in aerospace industry. Repairing of Inconel 718 components has been usually carried out using atmospheric plasma spray (APS) and high velocity oxy fuel (HVOF) spray techniques. Cold spray (CS) is a relatively new thermal spray technique, which relies more on powders' kinetic energy and less on their thermal energy to impact powders onto the substrate, where the powders undergo severe plastic deformation and subsequently adhere to the substrate surface as coatings. In this work, high pressure CS using dry N-2 as propellant gas has been deployed to deposit Inconel 718 powders as thick coatings for structural restoration application. The coating's surface morphology, cross-section microstructure, crystallinity, residual stress and mechanical properties were subsequently characterized and compared with the Inconel 718 coating deposited by APS in order to elaborate the unique features of the Inconel 718 coatings deposited by both spray techniques.