TRANSIENT ELECTROCHEMICAL TECHNIQUES FOR STUDYING ELECTRODEPOSITION OF NIOBIUM IN FUSED NACL-KCL

被引：25

作者：

LANTELME, F

BERGHOUTE, Y

机构：

[1] Laboratoire d'Electrochimie, URA 430 CNRS, Université Pierre et Marie Curie

来源：

JOURNAL OF THE ELECTROCHEMICAL SOCIETY | 1994年 / 141卷 / 12期

关键词：

D O I：

10.1149/1.2059331

中图分类号：

O646 [电化学、电解、磁化学];

学科分类号：

081704 ;

摘要：

The mechanism of the electroreduction of niobium chlorides dissolved in fused NaCl-KCl was determined by transient electrochemical techniques at temperatures ranging from 670 to 870 degrees C. At temperatures <750 degrees C it is shown that the stable oxidation states of niobium ions are Nb(V), Nb(IV), and Nb(III); reduction of Nb(III) gives rise to metallic niobium. At higher temperatures, Nb(V) tends to decompose into Nb(IV) with chlorine evolution. Introducing fluoride ions stabilizes the higher oxidation states. For a molar ratio F/Nb, r(F) > 2, Nb(V) is stable over the whole temperature range and the direct reduction Nb(IV) --> Nb is obtained as the Nb(III) species is no longer stable. The standard potentials of the redox reactions are calculated for various concentrations of fluoride ions. Presence of fluoride ions has a beneficial effect on the quality of the niobium deposit, a ratio r(F) similar to 2 is enough for obtaining coherent deposits:

引用

页码：3306 / 3311

页数：6

共 42 条

[1]

ARURAULT L, 1991, 3RD INT S MOLT SALT, V73, P305

[2]

ARURAULT L, 1992, THESIS I NATIONAL PO

[3]

BARD AJ, 1980, ELECTROCHEMICAL METH, P430

[4] ELECTRODEPOSITION OF NIOBIUM FROM FLUORONIOBATE K2NBF7 SOLUTIONS IN FUSED NACL-KCL [J].

BARHOUN, A ;

BERGHOUTE, Y ;

LANTELME, F .

JOURNAL OF ALLOYS AND COMPOUNDS, 1992, 179 :241-252

[5] INTERNAL REFERENCE SYSTEMS FOR FUSED ELECTROLYTES [J].

BERGHOUTE, Y ;

SALMI, A ;

LANTELME, F .

JOURNAL OF ELECTROANALYTICAL CHEMISTRY, 1994, 365 (1-2) :171-177

[6]

BERGHOUTE Y, 1993, THESIS U P M CURIE P

[7]

Bockris J. O M., 1970, MODERN ELECTROCHEMIS, V2, P991, DOI [10.1007/978-1-4613-4560-2_3, DOI 10.1007/978-1-4613-4560-2_3]

[8]

BRITZ D, 1988, DIGITAL SIMULATION E

[9]

BROOKER MH, 1983, ADV MOLTEN SALT CHEM, V5, P94

[10] RAMAN SPECTROSCOPIC STUDIES ON FUSED NBCL5 [J].

BUES, W ;

DEMIRAY, F ;

OYE, HA .

ZEITSCHRIFT FUR PHYSIKALISCHE CHEMIE-FRANKFURT, 1973, 84 (1-4) :18-24

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