熔盐电解LiCl-KCl-AlCl_3-La_2O_3共析出制备Al-Li-La合金

Preparation of Al-Li-La Alloys by Electrochemical Codeposition in LiCl-KCl-AlCl_3-La_2O_3 Melts

研究了LiCl-KCl-AlCl3-La2O3熔盐体系中共析出制备Al-Li-La合金的可行性。研究表明,在LiCl-KCl熔盐中,AlCl3将La2O3氯化为LaCl3,使电解制备Al-Li-La合金顺利进行。借助循环伏安法对熔盐体系的电化学行为进行分析发现,对质量比为45∶45∶5∶2的LiCl-KCl-AlCl3-La2O3熔盐,当阴极电流密度大于0.25 A/cm2,可以实现Al、Li和La的共析出。通过研究电解温度、阴极电流密度和电解时间对合金组成的影响,得到了较佳的电解参数:电解温度650℃,在LiCl-KCl混合熔盐中加入质量分数为5%的AlCl3和2%的La2O3,阴极电流密度12.5 A/cm2,电解时间1 h。X射线衍射对合金分析测试表明,合金主要由Al2La和βLi组成。

Electrochemical codeposition of Al-Li-La alloys were investigated in molten LiCl-KCl-AlCl3-La2O system. The results showed that chlorination of La2O3 by AlCl3 led to the formation of LaCl3 in the molten salts and promote the electrolytic preparation of Al-Li-La alloys. Transient electrochemical techniques, such as cyclic voltammetry and chronopotentiometry, were used to study the reaction mechanism. The electrochemical codeposition of Al, Li and La occurred when cathodic current densities were higher than 0.25 A/cm2 in the LiCl-KCl-AlCl3-La2O3 melts. The influencing factors such as electrolytic temperature, cathodic current density and electrolysis times on alloys were studied and the optimum electrolysis conditions were：a molten salt mixture of LiCl∶KCl∶AlCl3∶La2O3=45∶45∶5∶2（mass raito）, an electrolytic temperature of 650 ℃, a cathode current density of 12.5 A/cm2, and electrolysis time of 1 h. X-ray diffraction（XRD） indicated that the Al-Li-La alloys obtained by electrocodeposition mainly consisted of Al2La, and βLi phases.