Acta Phys. -Chim. Sin. ›› 2016, Vol. 32 ›› Issue (10): 2538-2544.doi: 10.3866/PKU.WHXB201607202

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Electrochemical Formation of Al-Tb Alloys from Tb4O7 Fluorinated by AlF3 in NaCl-KCl Melts

Wei HAN*(),Nan JI,Mei LI*(),Shan-Shan WANG,Xiao-Guang YANG,Mi-Lin ZHANG,Yong-De YAN   

  • Received:2016-05-19 Published:2016-09-30
  • Contact: Wei HAN,Mei LI E-mail:weihan@hrbeu.edu.cn;meili@hrbeu.edu.cn
  • Supported by:
    The project was supported by the National Natural Science Foundation of China(21271054,11575047,21173060);Major Research Plan of the National Natural Science Foundation of China(91326113,91226201);and Fundamental Research Funds for the Central Universities, China(HEUCF2016012)

Abstract:

To prepare Al-Tb alloys from Tb4O7 assisted by AlF3 in NaCl-KCl melts, we initially studied the effect of AlF3 on the dissolution of Tb4O7 by analyzing the supernatant and bottom salts. X-ray diffraction (XRD) results revealed that Tb4O7 was fluorinated by AlF3 to form TbF3. The electrochemical behavior of the NaCl-KCl-AlF3-Tb4O7 system was investigated using a Mo electrode at 1073 K. Cyclic voltammetry (CV), square wave voltammetry (SWV), chronopotentiometry (CP) and open circuit chronopotentiometry (OCP) analyses indicated that the under-potential deposition of Tb(III) occurred on pre-deposited Al. The co-deposition of Al-Tb alloys was investigated by galvanostatic electrolysis under different conditions. These samples were characterized by XRD and scanning electron microscopy and energy dispersive spectrometry (SEM-EDS). The Al-Tb alloy obtained by galvanostatic electrolysis at -2.5 A consisted of Al and Al3Tb phases. The effects of the electrolysis conditions on the composition of the alloy and current efficiency were studied by analyzing the compositions of the Al-Tb alloys by inductively coupled plasma-atomic emission spectrometer (ICP-AES). The current efficiency could reach 76.5% under the conditions of galvanostatic electrolysis at -1.5 A for 2 h.

Key words: Electrochemical behavior, Tb4O7, Co-reduction, NaCl-KCl melt, Al-Tb alloy, Current efficiency

MSC2000: 

  • O646