Feasibility of Nitrogen as a Carrier Gas for Inconel Cold Spray in Hydropower Application

Cold spray deposition of Inconel alloys has emerged as a promising strategy for mitigating cavitation erosion in hydropower facilities. Most prior developments employ helium (He) as the carrier gas because it enables high particle velocities and dense coatings. However, He is nearly two orders of magnitude more expensive than nitrogen (N 2 ), which limits its widespread adoption in the hydropower sector. Although He‐based cold spray can be justified for high value repairs, the lower cost and broad availability of N 2 make it an attractive alternative. This study assesses the feasibility of N 2 ‐based cold spray of Inconel powders for hydropower applications. Cavitation erosion testing shows that a He‐based coating exhibits cavitation resistance of 398% relative to the SS304L substrate. In contrast, the N 2 ‐based coating shows substantially lower cavitation resistance, reaching only ∼69% of the substrate, even under higher carrier gas temperature and pressure. Reducing the Inconel powder size from 44 to 22 µm significantly improves performance to ∼148% of the substrate, and further enhancement to ∼172% of the substrate is achieved by incorporating fine chromium carbide particles. Overall, with optimized feedstock design, N 2 ‐based cold spray offers a practical and cost‐effective approach for producing cavitation resistant coatings on hydropower components.