Deciphering when Metal Corrosion is Spontaneous in Molten Fluorides Using Potential-Activity Diagrams

Abstract

ABSTRACT The work identifies the conditions for thermodynamically favored spontaneous metal corrosion using potential-activity diagrams tailored for high-temperature molten fluorides. These diagrams provide insights on the thermodynamic phase stability of both solid and dissolved metal species, such as Cr, Cr(II), Ni, Ni(II), Fe, and Fe(II), along with their potential primary oxidizers, including Eu(III), O2, and HF, over a broad range of theoretical F- anion activities. The work further examines the practical implications, prospects, and challenges associated with construction of these diagrams. The key objective of this research is to pinpoint crucial thermodynamic variables that substantially affect metal corrosion in the context of molten salt nuclear reactor applications.