Passivation Behaviors of Mo, W Electrodes in MgCl₂-KCl-NaCl-CaCl₂ Molten Salt for Electrolysis of Magnesium

Authors

• Ye CHEN, Key Laboratory of Superlight Materials and Surface Technology, Ministry of Education, Harbin Engineering University, Harbin 150001, China;Follow
• Ke YE, Key Laboratory of Superlight Materials and Surface Technology, Ministry of Education, Harbin Engineering University, Harbin 150001, China;

Corresponding Author

Ye CHEN(chenye@hrbeu.edu.cn)

Abstract

The discharge process and passivation behaviors of Mg(Ⅱ) on cathode(Mo, W) in MgCl₂-KCl-NaCl-CaCl₂ molten salt system had been investigated by means of cyclic voltammetry and chronoamperometry. The composition of molten salt was MgCl(10%) + CaCl(20%) + NaCl(60%) + KCl(10%)(by mass) and the temperature of electrolysis was 725 ℃. The deposition potential of Mo was 37 mV more negative than that of W, while the peak current was sharper than Mo according to the voltammograms at 0.05 V/s, indicating that the passivation on Mo cathode is easier than W. The formation of MgO impurities during the electrolysis could cause the cathode passiration. However, the reversibility on the discharge reaction of W cathode was better than Mo electrode, and the reduction peak potential of W electrode almost unchanged with the scan rate. The I～t^-1/2 curves demonstrated a positive linear relationship on W electrode, but deviated from the linear characteristics on Mo electrode due to the passivation.

Keywords

molten salt, magnesium, cathode discharge, passivation

DOI Link

https://doi.org/10.61558/2993-074X.1890

Publication Date

2008-05-28

Online Available Date

2008-05-28

Revised Date

2007-12-06

Received Date

2007-10-17

Recommended Citation

Ye CHEN, Ke YE. Passivation Behaviors of Mo, W Electrodes in MgCl₂-KCl-NaCl-CaCl₂ Molten Salt for Electrolysis of Magnesium[J]. Journal of Electrochemistry, 2008, 14(2): 197-199.
DOI: 10.61558/2993-074X.1890
Available at: https://jelectrochem.xmu.edu.cn/journal/vol14/iss2/17