Effect of the Li Reduction to Electrodeposition of Nd-Sn Compounds in Liquid Sn Electrode in LiCl-KCl-NdCl3 Melt

Abstract

The electrochemical behaviors of Li+ and Nd3+ were investigated on W, liquid Sn pool and Sn film electrodes in LiCl-KCl-NdCl3 melt at 673 K. Various electrochemical techniques, such as cyclic voltammogram, square wave voltammogram, and open circuit chronopotentiometry, were conducted to evaluate the electrochemical behaviors of Li+ and Nd3+. The reduction of Nd3+ was found to be a two-step process in the W electrode and a one-step process in the liquid Sn electrode. During the formation of the Nd-Sn intermetallic compounds, only the NdSn3 would be formed without the reduction of the Li+ in the liquid Sn electrode. When the reduction potential moves over −2.77 V vs Cl2/Cl−, the Li+ in the electrolyte would inevitable be reduced into the liquid Sn electrode. The Nd-Sn intermetallic compounds were deposited on the liquid Sn pool electrode at −2.74 V vs Cl2/Cl− in the LiCl-KCl-NdCl3 melts for 5 h. The products were characterized by SEM-EDS and XRD. The loose product on the surface of the deposition displayed the existence of NdSn3 in Nd-Sn intermetallic compounds. The high content of Nd inclusion formed by segregation was detected in the solidified Sn electrode.