Pulsed-Potential Electrodeposition of Zirconium in a Molten LiCl-KCl Salt: Improvements in the Selectivity and Adhesion Strength

Abstract

This study demonstrates the pulsed-potential electrodeposition of reduced Zr species (ZrCl and Zr) in a molten LiCl-KCl salt. We report, for the first time, a new reduction reaction of Zr species (-1.90 V vs Ag/AgCl 10 wt%) in molten LiCl-KCl salt, characterized by cyclic-voltammetry experiments using W and Zr electrodes. The pulsed-potential electrodeposition experiments were performed using an inert W-foil electrode in a molten ZrCl4-LiCl-KCl salt. Three cathodic-pulse potentials (-1.30, -1.60, and -1.90 V) were applied, and the chemical and structural characteristics of respective deposits were compared. The deposits were characterized by scanning electron microscopy with energy-dispersive x-ray spectroscopy, x-ray diffraction analysis, and Raman spectroscopy. Additionally, we accomplished the pulsed-potential electrodeposition (>10(3) A m(-2)) of alpha-Zr metal with a practical ZrCl4 concentration (2.6 wt%). The results confirm that pulsed-potential electrodeposition can be employed for the selective deposition of the alpha-Zr metal by minimizing the co-production of ZrCl in molten LiCl-KCl salt while achieving excellent adhesion to the inert W electrode.