中文摘要：

在773K条件下,研究了La（III）在LiCl-KCl熔盐中W和Ni电极上的电化学行为。La（III）还原反应是一步三电子转移的准可逆反应;通过在Ni电极上直接电沉积La的方法可以获得La-Ni金属间化合物;恒电位电解可以获得含三种金属间化合物（LaNi5、La7Ni16和La2Ni3）的La-Ni合金层,并且通过X射线衍射仪（XRD）和扫描电镜-能谱分析仪（SEM-EDS）确定物相并表征结构。采用开路计时电位法估算了LaNi5金属间化合物的标准生成吉布斯自由能。揭示了恒电位电解方法是制备La-Ni镀层合金以及提取熔盐中La的有效方法。

英文摘要：

Electrochemical and thermodynamic studies on the formation of La-Ni intermetallic compounds in molten LiCl-KCl-（3.5%（w））LaCl3 at 773 K were performed. The electrochemical reduction of La（III） ions was investigated on inert W and reactive Ni electrodes by cyclic voltammetry. The reduction potential of La（III）/La on a Ni electrode was observed at more positive potential than that on a W electrode because of the formation of La-Ni intermetallic compounds when La ions reacted with the Ni substrate. Square-wave voltammetry, chronopotentiometry, and open-circuit chronopotentiometry provided further evidence for the formation of La-Ni intermetallic compounds. Potentiostatic electrolysis on a Ni electrode led to the formation of three La-Ni intermetallic compounds, LaNi5, La7Ni16 and La2Ni3, according to X-ray diffraction （XRD） and scanning electron microscopy-energy-dispersive X-ray spectroscopy （SEM-EDS） analyses. The standard Gibbs free energies of formation for LaNi5 were estimated from open-circuit chronopotentiometric measurements using the Gibbs-Helmholtz equation and Hess law. The formation of the La-Ni alloy layer could be controlled by the applied potential and time. Potentiostatic electrolysis was an effective method for electrochemical extraction of La.