The influence of oxide on the electrochemical processes in K{sub 2}NbF{sub 7}-NaCl-KCl melts

Journal Article · Fri Dec 01 04:00:00 EST 1995 · Journal of the Electrochemical Society

DOI:https://doi.org/10.1149/1.2048470· OSTI ID:197686

Lantelme, F; Berghoute, Y ^[1]; Barner, J.H. von ^[2]; Picard, G S ^[3]

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1. Univ. Pierre et Marie Curie, Paris (France). Lab. d`Electrochimie
2. Technical Univ. of Denmark, Lyngby (Denmark). Inst. of Mineral Industry
3. ENSCP, Paris (France). Lab. d`Electrochimie et Chimie Analytique

Transient electrochemical techniques showed that in NaCl-KCl melts the reduction of K{sub 2}NbF{sub 7} occurs through a two-step reaction Nb(V) {yields} Nb(IV) {yields} Nb. When oxide ions were introduced, cyclic voltammetry indicated that the waves corresponding to reduction of the complex NbF{sub 7}{sup 2{minus}} progressively disappeared. Oxo complexes, such as NbOF{sub n}{sup (n{minus}3){minus}}, are reduced at a potential close to that of the Nb(IV) fluoro complexes. Niobium metal deposition was perturbed by the formation of niobium suboxides like NbO or Nb{sub 4}O{sub 5}. For molar ratios of oxide to Nb greater than one, a black layer of niobium oxide, NbO{sub 2}, appeared at the electrode surface. The present study confirms the high oxygen affinity of niobium and shows that a careful purification of the electrolyte and feeding materials is required for producing niobium with a low oxygen content.

• Sponsoring Organization: USDOE
• OSTI ID: 197686
• Journal Information: Journal of the Electrochemical Society, Journal Name: Journal of the Electrochemical Society Journal Issue: 12 Vol. 142; ISSN 0013-4651; ISSN JESOAN
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
40 CHEMISTRY
ELECTRODEPOSITION
ELECTROLYSIS
MOLTEN SALTS
NIOBIUM
NIOBIUM FLUORIDES
NIOBIUM OXIDES
OXYFLUORIDES
POTASSIUM CHLORIDES
POTASSIUM FLUORIDES
REDUCTION
SODIUM CHLORIDES
VOLTAMETRY