Tantalum electrochemistry in chloride-fluoride and oxochloride-fluoride melts

摘要

Two papers dedicated to studying tantalum electrodeposition from NaCl-KCl-K_2TaF_7 melt are knwon in the literature [1,2]. These authors showed that tantalum reduction occurred through a single reduction step: Ta(V)+5c <->Ta(0). In the first of them Lantelme et al. established a spontancous formation of tantalum and oxygen compounds on a tantalum wire emmersed in a molten electrolyte. The Na_2O and BaO additionsto the NaCl-KCl-K_2TaF_7 melt [1] at a molar ratio O/Ta-=1 resulted in formation of an oxohalide TaOCl_xF_y~(z-) complex, where z=x+y-3, to which a single peak of tantalum reductioon corresponded on voltammograms. The nature of this complex has not been established yet. Increase of the 2