The production of alloys by molten salt electrolysis is an important scientific and technical challenge. Developing criteria for the rational selection of metal co-deposition conditions in an electrochemical cell with consumable anodes helps solve the problem of controlled alloy electrodeposition. In this work, an approach based on comparison of equilibrium potentials for two metal ion/metal pairs (A/A and B/B) is proposed to find the initial electrolysis parameters (concentration ratio and operating temperature). Theoretical analysis indicates the existence of regions of thermodynamic equilibrium for A/A and B/B pairs in the melt-solvent with a certain ratio of the A and B ion concentrations. Experimental and calculated values of equilibrium potentials for a wide range of metals in a melt based on an equimolar NaCl-KCl mixture containing 1 mol.% of depositing ions at 1000 K are compared. Venn-Euler diagrams are constructed for the pairs Ni/Ni, Mo/Mo, Cr/Cr, Pd/Pd, Rh/Rh, Ru/Ru and Ir/Ir in the temperature range from 948 to 1123 K and ion concentrations in the melt from 0.1 to 2 mol.%. The equilibrium regions in the Ni/Ni and Mo/Mo, Pd/Pd and Rh/Rh, Ru/Ru and Ir/Ir systems are calculated. It is shown that as the temperature decreases, the equilibrium regions expand for the studied pairs of noble metals, but narrow for nickel and molybdenum. The practical application of this method for a specific system requires taking into account additional data on the liquidus temperature and the vapor pressure of the melt to limit the equilibrium region on the left and right, respectively.
Isakov et al. (2025) studied this question.