采用循环伏安、方波伏安、计时电位和开路计时电位等电化学方法研究了Pr (Ⅲ)离子在共晶LiCl-KCl熔盐中Ni电极上的电化学行为及Pr-Ni合金化机理.结果表明, Pr(Ⅲ)离子的电化学还原过程为三电子转移的一步反应.与惰性Mo电极上的循环伏安曲线相比, Pr(Ⅲ)离子在活性Ni电极的循环伏安曲线上还出现了4对氧化还原峰,表明Pr(Ⅲ)离子在Ni电极上发生欠电位沉积,是由于生成不同的Pr-Ni金属间化合物.采用X射线衍射仪和扫描电子显微镜-能谱仪等对恒电位电解的产物进行了表征.结果表明,在不同电位下进行恒电位电解时,每个电位上只得到一种 Pr-Ni 金属间化合物,分别为 PrNi2, PrNi3, Pr2 Ni7和PrNi5.%The electrochemical behavior of Pr (Ⅲ) on a Ni electrode in the LiCl-KCl melt and the alloying mechanism of Pr-Ni alloys were investigated by cyclic voltammetry, square wave voltammetry, chronopoten-tiometry and open-circuit chronopotentiometry. Cyclic voltammetry and square wave voltammetry experiments indicate that the reduction of Pr(Ⅲ) ions into Pr metal occur in a single step with three electrons exchanged. Compared with the cyclic voltammograms on an inert Mo electrode, four reduction peaks are observed, which indicates the under-potential deposition of Pr (Ⅲ) on the reactive Ni electrode due to the formation of Pr-Ni intermetallic compounds. The Pr-Ni alloys obtained by potentiostatic electrolysis were characterized by X-ray diffraction(XRD) and scanning electron micrograph-energy dispersive spectrometry(SEM-EDS). The results show that only one Pr-Ni intermetallic compound, i. e. PrNi2 , PrNi3 , Pr2 Ni7 or PrNi5 , is obtained at each po-tential, respectively. This process can also be used for other electrochemical formation of lanthanide-Ni alloys.
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