Material Selection and Corrosion Studies of Candidate Bearing Materials for Use in Molten Chloride Salt

Molten chloride salts are being given strong consideration for use in heat transfer and storage in concentrating solar power (CSP) systems as well as in some nuclear reactor applications. Containment of the molten salt, particularly at the highest temperatures, is a major material concern and has received considerable study. Another material issue is the pumps that will be required to move the molten salt along with the bearing materials that will be required to have sufficient corrosion resistance as well as wear resistance in the high temperature salt. A pair of coordinated studies in our laboratory has addressed the corrosion, and the wear issues of candidate bearing materials including the selection of candidate materials as well as their performance in a molten sodium chloride-potassium chloride-magnesium chloride salt environment. This article addresses the selection of candidate materials and their chemical compatibility with the molten salt. The studies have identified material pairs that have suitable properties for use as bearings that would be immersed in molten chloride salt.