摘要
用循环伏安法、恒电位电解断电后的电极电位时间曲线、电位阶跃法和Ｘ射线衍射法研究了铁电极在ＮａＣｌＫＣｌＤｙＣｌ３熔体中的电化学行为，获知Ｄｙ３＋在Ｆｅ电极上的还原过程，首先是生成ＤｙＦｅ合金，然后才析出纯金属Ｄｙ；验证了ＤｙＦｅ合金体系中化学计量化合物的数目。计算了化学计量化合物在１０７３Ｋ的标准生成自由能，在１０２３～１１２３ＫＤｙ原子在ＤｙＦｅ合金相中的扩散系数与温度的关系式为ｌｎＤ＝－７２９×１０３／ＲＴ－１４７，其扩散活化能为７２９Ｋ·ｍｏｌ－１。用自耗阴极法制取了含Ｄｙ高达９０％的ＤｙＦｅ合金，其物相为ＤｙＦｅ３和Ｄｙ。
?The cyclic voltammetry and electrode potentialtime curve after potentiostatic electrolysis, potentialstep method and Xray diffraction were used to study the electrode process of Dy3+ reduced on Fe cathode in molten NaClKClDyCl3. At first, the DyFe alloys forms, then the intermetallic compounds of DyFe containing more Dy form in sequence. The metallic Dy deposits at last. The number of compounds in DyFe alloy has been tested at 1073 K. The standard free energy of formation for (1/2)Dy2Fe17, (1/6)Dy6Fe23, DyFe3 and DyFe2 determined are -9264, -8310, -7699 and -5905 kJ/mol at 1073 K. The relationship between diffusion coefficient and temperature of Dy atom in DyFe layer can be expressed as lnD=-729×103/RT-147, and the diffusion activation energy is 729 kJ·mol-1. The DyFe alloy was prepared by consumable cathode in molten chlorides. The DyFe alloy contained Dy near 90%(wt) was obtained. The phases of alloy were DyFe3 and Dy.
出处
《中国稀土学报》
CAS
CSCD
北大核心
1997年第4期300-303,共4页
Journal of the Chinese Society of Rare Earths
基金
广东省科学基金
关键词
镝铁合金
熔盐电解
电化学合金化
Rare earths, Dy, DyFe alloy, Molten salt electrolysis, Electrochemistry
