Cold spray repair of cavitation damages: a holistic process optimization approach

With the ambitious goal of doubling its electricity generation capacity by 2050, Hydro-Québec—one of the world’s largest hydropower producers—faces the critical challenge of maintaining reliable operations while minimizing equipment downtime. In this context, developing efficient and innovative solutions to repair cavitation damages on key assets such as turbines has become essential. In recent years, the cold spray (CS) process has gained significant attention for such applications due to its ability to produce thick, dense coatings without adversely affecting the substrate material. Building on a first collaboration between 2021 and 2023 that confirmed the feasibility of using cold spray for turbine repair, Hydro-Québec, Polycontrols, and the National Research Council of Canada have pursued further research to enhance the cavitation resistance of CS coatings. This presentation will highlight the results of a comprehensive process optimization study conducted on two different steels, encompassing powder selection, cold spray parameters, and post-processing treatments. Cavitation testing, detailed analyses, and comparisons with reference materials (cast components and welded repairs) reveal clear opportunities for implementing cold spray technology in hydropower equipment repair.