KCl熔体中钬离子在钴电极上的还原

Electroreduction of Holmium Ion on the Cathode Cobalt in Molten KCI-HoCl_3 System

用循环伏安法、恒电位电解断电后的电位─时间曲线、电位阶跃下的电流─时间曲线以及Ｘ─射线衍射法研究了在ＫＣｌ─ＨｏＣｌ３熔体中Ｈｏ３＋在钴电极上还原的电极过程。Ｈｏ３＋在钴电极还原时，在形成金属间化合物Ｈｏ２Ｃｏ１７等后才析出纯金属钬，确定了形成Ｈｏ２Ｃｏ１７这一步是可逆的。测定了Ｈｏ２Ｃｏ１７等五种金属间化合物的生成自由能和Ｈｏ原子在Ｈｏ２Ｃｏ１７中的扩散系数及扩散活化能。

Cyclic voltammetry, open current potential-time curve after potentiostatic electrolysis,current-time curve at potential step and x-ray diffraction were used to study the electrode process of Ho3+ reduction on cobalt electrode in molten KCl-HoCl3. The intermetallic compounds of Ho2Co17 et al. are formed at first,and then metallic cobalt electrode is deposited when Ho3+ is reduced on the cobalt electrode. The reaction 2Ho3+ + 17Co+ 6e =Ho2Co17 is reversible.The formation free energies of the intermetallic compounds between Ho and Co,the diffussion coefficients and the diffusion activation energy of Ho atom in the alloy phase are determined.