Electrochemical study of aluminium deposition from molten NaF-AlF3-Al2O3 on a tungsten electrode

Article abstract of DOI:10.1016/0013-4686(89)85014-5

The deposition of aluminium from molten NaF-AlF₃-Al₂O₃ systems was studied at a tungsten electrode at temperatures of 824-902°C. The mechanism of the deposition was evaluated using cyclic voltammetry and chronopotentiometry. The deposition reaction is quasi-reversible involving a transfer of three electrons to form intermetallic compounds of Al and W, followed by bulk aluminium deposition. The charge transfer reaction is followed by a chemical reaction between Al and the electrolyte to produce dissolved metal. Using the total concentration of AlF₆^3- and AlF₄^- ions, diffusion coefficients of the order of 10^-6 cm² s^-1 were calculated.