The pits and cracks that form on the surface of hydroelectric power turbines due to cavitation result in high repair costs and lost revenue for dam operators, who must shut the power systems down to effect repairs. The arc welding processes typically applied melts and degrades metal, exacerbating cavitation damage. Cold spray, a coating and powder consolidation process developed by VRC Metal Systems, offers a different and more efficient route to turbine protection.

The process deposits tiny metal particles onto damaged areas of a turbine at supersonic speeds. No melting occurs and the particles impact the surface hard enough to form a bond, producing materials and coatings with superior hardness, wear resistance and corrosion resistance. The cold spray technique can render turbine blades significantly more resistant to damage over arc welding repair approaches.

Source: VRC Metal SystemsSource: VRC Metal Systems

U.S. Pacific Northwest National Laboratory and hydropower industry collaborators are planning field evaluations to validate the merits of cold spray technology. According to researchers, the process can also be applied for corrosion damage mitigation in nuclear waste storage canisters.

To contact the author of this article, email shimmelstein@globalspec.com