Effect of processing conditions on the mechanical performance of stainless steel cold sprayed coatings

Abstract

Different types of metallic infrastructures are exposed to atmospheric conditions and, consequently, suffer deterioration over the years. The metallic structures can be repaired by replacing the components by new ones. This increment the maintenance costs. However, the damaged components can be repaired by depositing a coating on their surface. Traditionally, the technique used to deposit steel coatings has been High Velocity Oxi-Fuel (HVOF). However, this high temperature thermal spray method presents some problems due to the possible oxidation of the powder during the spraying process. Additionally, the reparation of a metallic structure could require thickness unattainable by this technique. An alternative could be the Cold Spray (CS) deposition. CS constitutes a coating deposition technology that permits in-situ repair of structures, with little or no detrimental effects to the main component. For these reasons, this research compares the performance of 316L coatings processed by CS with those traditionally deposited by HVOF onto a S355-J2 structural steel. Adhesion tests were planned to quantify the adherence of the coatings. Additionally, the mechanical response of coatings and substrate was measured by nanoindentation tests. Finally, the microstructure of the coatings was correlated with their mechanical response.