Effect of oxygen impurity in sodium–potassium melt on the corrosion processes at the interface between vanadium alloy and eutectic melt

Abstract

An analysis of available experimental data on thermodynamic activity coefficient of oxygen in binary liquid metal Na–K alloys is carried out. Thermodynamic correlations based on the coordination cluster model are used for theoretical evaluation of the effect of oxygen impurity on the solubility of vanadium in sodium–potassium eutectic alloy in the temperature range of 400–800°C. Isothermal capsule experiments qualitatively confirm the results of calculations of vanadium solubility in Na–K melt. On the basis of derived thermodynamic relationships the threshold concentration for the formation of ternary oxide NaVO₂ on the surface of the solid vanadium in the Na_0.32K_0.68 melt has been calculated. The calculation results are compared with the corresponding values for the sodium coolant.