Alloying effects in high temperature molten salt corrosion

This study investigates dealloying of Fe-(Cr)-Ni model alloys in molten chloride salts that simulate the heat -transfer circuits of molten salt nuclear reactors. Classical dealloying with porosity formation is observed as the dominant form of corrosion at low homologous temperature, and the usual, fundamental, geometric parting limit for dealloying, 55-60 at% of the reactive element(s) (Fe and Cr), is decreased by several percent. This deviation is due to increased surface diffusivity of the more-noble element, Ni, in molten Cl salts. To better highlight deviations from conventional dealloying theory, results are compared with dealloying of similar Fe-(Cr)-Ni alloys in concentrated caustic solutions.

Automated summary

This study investigates the dealloying phenomenon of Fe-(Cr)-Ni model alloys in molten chloride salts that simulate the heat-transfer circuits of molten salt nuclear reactors. Classical dealloying with porosity formation is observed as the dominant form of corrosion at low temperatures. Additionally, the increased surface diffusivity of the more-noble element, Ni, in molten chloride salts decreases the critical parting limit for dealloying.