Corrosion Electrochemical Behavior of Molybdenum in the LiCl–KCl Melt Containing Additives of Cerium and Neodymium Trichlorides

The corrosion electrochemical behavior of molybdenum depending on the melt composition (imitators of spent nuclear fuel (SNF) components) in an oxidizing atmosphere is studied. Thermodynamic analysis of possible corrosion processes is performed using the HSC Chemistry 9.0 software in the Equilibrium calculations module. The rate of metal corrosion is estimated using gravimetry. The real products of the corrosion process and those expected from the thermodynamic calculations are compared using electron probe microanalysis (EPMA) and X-ray diffraction (XRD) analysis. The molybdenum concentration in frozen melt samples is studied by an atomic absorption method. The rate of molybdenum corrosion depends on the testing time. The decrease in the corrosion rate in time can be explained by the accumulation of Nd 3+ and Ce 3+ ions in the near-electrode layer, and corrosion occurs in the diffusion mode. The corrosive activity of the salt melt increases with the temperature and the ionic strength of the melt.