Electrodeposition of tantalum and its electrochemical behaviors in molten NaCl-KCl

Abstract

This paper systematically studied the electrochemical behaviors of tantalum ions in NaCl-KCl molten salt, and pure metallic tantalum was collected on the cathode. Through a series of electrochemical methods such as cyclic voltammetry, square wave voltammetry, and chronopotentiometry, the reduction and diffusion processes of tantalum ions in NaCl-KCl molten salt were determined. The diffusion coefficient and nucleation mode of tantalum ions were investigated, and the electrodeposition was carried out at a certain potential. The results showed that the electrode reduction process of tantalum ion in NaCl-KCl molten salt at 1023 K is a two-step reaction Ta(V)→Ta(II)→Ta, and the reaction Ta(V)→Ta(II) was reversible and controlled by diffusion. The nucleation mode of tantalum ion was determined to be instantaneous nucleation by chronoamperometry. The cathode deposition product was analyzed by SEM, EDS and XRD, and it was confirmed that the deposition product was granular and the main component was tantalum.