Electrochemical codeposition of Mg-Li-Gd alloys from LiCl-KCl-MgCl2-Gd2O3 melts
(1. Key Laboratory of Superlight Materials and Surface Technology of Ministry of Education,
Harbin Engineering University, Harbin 150001, China;
2. College of Chemistry and Chemical Engineering, Harbin Normal University, Harbin 150025, China;
3. Institute of Petrochemistry, Heilongjiang Academy of Sciences, Harbin 150040, China)
Harbin Engineering University, Harbin 150001, China;
2. College of Chemistry and Chemical Engineering, Harbin Normal University, Harbin 150025, China;
3. Institute of Petrochemistry, Heilongjiang Academy of Sciences, Harbin 150040, China)
Abstract: Mg-Li-Gd alloys were prepared by electrochemical codeposition from LiCl-KCl-MgCl2-Gd2O3 melts on molybd, enum electrode with constant current density at 823 and 973 K. The microstructure of the Mg-Li-Gd alloys was analyzed by X-ray diffraction (XRD), optical microscopy (OM) and scanning electron microscopy (SEM). The results show that magnesium and gadolinium deposit mainly in the first 30 min, and the alloy obtained contains 96.53% Mg, 0.27% Li and 3.20% Gd (mass fraction). Then, the reduction of lithium ions occurs quickly. The composition of alloy can be adjusted by controlling electrolysis time or Gd2O3 concentration in LiCl-KCl melts. With the addition of Gd into Mg-Li alloys, the corrosion resistance of the alloys is enhanced. XRD results suggest that Mg3Gd and Mg2Gd can be formed in Mg-Li-Gd alloys. The distribution of Gd element in Mg-Li-Gd alloys indicates that Gd element mainly distributes at the grain boundaries of Mg-Li-Gd alloys.
Key words: electrochemical codeposition; Mg-Li-Gd alloy; chloride melt; galvanostatic electrolysis; Gd2O3