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The kinetics of the anodic process at platinum in KF-NaF-AlF 3 -Al 2 O 3 melts in the temperature range 725-800°C is studied using potentiostatic polarization. Platinum is considered as an indifferent oxy gen evolving electrode, and a two stage scheme is proposed for the anodic process on it. According to this scheme, primary charge transfer with the formation of adsorbed O ads particles is accompanied by their des orption according to a physical or an electrochemical mechanism. The polarization dependences of the anodic process on platinum are calculated under stationary conditions with allowance for the predominance of different stages of the process and a desorption mechanism. The calculated and experimental stationary anodic polarization dependences are compared.

The rate of oxygen evolution on metallic inert anodes was measured as a function of current density during electrolysis of a low-melting NaF(12)-KF-AlF 3 bath ([NaF ? KF]/[AlF 3 ] = 1.5 mol mol -1 ) at 800°C. The oxidation rate of the anode substrate (A cm -2 ) was calculated. The anode oxidation process was depressed at the potentials of oxygen evolution. The dynamics of the decrease in the oxidation rate, which were obtained in previous study by the change in geometrical size of the metallic part of the specimen, was reproduced both by the technique proposed and also in potentiostatic electrolysis at potentials below that of oxygen evolution, in some cases, depending on prepolarisation.

Abstract. Some features of behavior and kinetic of the anodic processes for the platinum and Cu–Fe–Ni alloy in the KF–NaF–AlF3–Al2O3 melts at 1025–1055 K have been studied by cyclic voltammetry and chronopotentiometry.The obtained results allowed us to conclude that mechanisms of the anodic processes at the platinum and Cu–Fe–Ni alloy are similar. Both mechanisms include the oxidation stage of electrode material. A rate of this stage is determined to depend significantly on the melt temperature.

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