Electrodeposition of Beta-Tantalum in Alkali Metal Halides and Oxohalide Melts

Abstract

Data on the electrolytic preparation of β-Ta in halide and oxohalide melts were reported. It was shown that during electrolysis in halide melts containing K2TaF7, the amount β-Ta in the cathodic products can be markedly increased by using a copper cathode with a definite texture. It was found that in chloride-oxofluoride melts the β-Ta content increases monotonically on passing from NaCl to KCl and RbCl melt. The dependencies of the β-Ta content in cathodic products on the ratio of oxygen to tantalum concentrations were studied in chloride-oxofluoride and fluoride-oxofluoride melts. The maxima of these dependences were identified and explained. It was shown that β-Ta could be obtained by electrolysis in molten salts only at temperatures below 850 °C.