The Electrochemical Behavior Of La(?) On Different Electrodes And The Preparation Of La Alloys By Electrolysis In Molten Salts

Mg-Li alloys have widely application in many fields, and the study on formation of Mg-Li alloy's with high performance has been focused on for many years. In order to prepared the Mg-Li-Mn/Sn-La alloys, the mechanism of electrochemical reaction, alloy microstructure and electrolytic conditions were studied in the molten salt. And the electrochemical behavior of La??? and the formation mechanism of its alloy were studied on the active nickel electrode, aluminum electrode and magnesium pre-deposited electrode.And the alloy's obtained in potentiostatic electrolysis was characterized by XRD?SEM and EDS.The main work is as follow:1. The electrochemical reduction of La??? ions on Mo electrode in LiCl-KCl-LaCl₃ molten salt system were studied at 500? , and the diffusion coefficients of La?III? ions were calculated. The electrochemical behavior of La??? ions on a nickel electrode in LiCl-KCl-LaCl₃ molten salt system was studied by the transient and steady state electrochemical method at 500 ? The La₂Ni₃,La₇Ni₁6 and LaNi₅ obtained by potentiostatic electrolysis on nickel electrode were characterized by X-ray diffraction ?XRD?, scanning electron microscopy ?SEM? with energy dispersive spectrometry ?EDS?. Thermodynamic properties of La-Ni intermetallic compounds were researched. The electrochemical behavior of La??? ions on Al electrode in LiCl-KCl-LaCl₃ molten salt system was studied. Al₁1La₃ which was indicated by X-ray diffraction ?XRD?, were prepared by potentiostatic electrolysis on nickel electrode. And the cathodic processes of Mg?II? ions on Mo electrode in LiCl-KCl-LaCl₃ molten salt system was studied, and the electrochemical behavior of La?III? ions on pre-deposited magnesium electrode in LiCl-KCl-MgCl₂ molten salt system was also studied.2.The electrochemical processes of Sn??? ions on molybdenum electrode in LiCl-KCl-LaCl₃ molten salt system was studied at 600?, and the diffusion coefficients of Sn?II? ions were calculated. The co-deposition mechanism of the magnesium, lithium, tin and lanthanum in LiCl-KCl-MgCl₂-SnCl₂-LaCl₃ molts was studied by electrochemical transient method. The co-deposition of magnesium, lithium, tin and lanthanum metal ions occurs when the current density less than -0.248 A cm^-2 or cathodic potential below -2.30V.Alloy samples were analyzed by XRD and SEM-EDS,which indicate that phase composition and metal element contents in alloys can be controlled by electrolytic parameter.3 .The electrochemical reduction of Mn?II? ions on molybdenum electrode in LiCl-KCl-LaCl₃ molten salt system was studied at 600 ?. The formation mechanism for Mg-Li-La-Mn alloys has been studied by electrochemical transient methods in LiCl-KCl-MgCl₂-MnCl₂-LaCl₃. The results show that co-deposition of magnesium, lithium,manganese and lanthanum occur when current density less than -0.434 A cm^-2 or cathodic potential below -2.35V. Alloy samples were analyzed by XRD and SEM-EDS. The results show that the Mg-Li-La-Mn alloys were produced, and the phase composition and metal element contents in alloys can be controlled by electrolytic parameters.