2019-Sustainable Industrial Processing Summit
SIPS2019 Volume 1: Angell Intl. Symp. / Molten Salt, Ionic & Glass-forming Liquids: Processing and Sustainability
| Editors: | F. Kongoli, M. Gaune-Escard, J. Dupont, R. Fehrmann, A. Loidl, D. MacFarlane, R. Richert, M. Watanabe, L. Wondraczek, M. Yoshizawa-Fujita, Y. Yue |
| Publisher: | Flogen Star OUTREACH |
| Publication Year: | 2019 |
| Pages: | 177 pages |
| ISBN: | 978-1-989820-00-1 |
| ISSN: | 2291-1227 (Metals and Materials Processing in a Clean Environment Series) |
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Electrochemical Behaviour of Tungsten Oxide and its Compounds in Carbamide Melts
Sergei Devyatkin1; Svetlana Kochetova2;1INSTITUTE OF GENERAL AND INORGANIC CHEMISTRT, Kiev, Ukraine; 2V.I. VERNADSKY INSTITUTE OF GENERAL AND INORGANIC CHEMISTRY OF THE NATIONAL ACADEMY OF SCIENCES OF UKRAINE, Kyiv, Ukraine;
Type of Paper: Regular
Id Paper: 14
Topic: 13
Abstract:
Carbamide melts have been discovered as applications as electrolytes for electrochemical treatment of metals [1]. As an example, the possibility of electrodeposition of refractory metals from carbamide melts at 135°С has been examined for tungsten. WO3 was insoluble in carbamide melts. The solubility of Li2WO4, Na2WO4, and K2WO4 in carbamide melts at 135°С reaches 5 wt.%, which makes it possible to carry out voltammetric studies and electrolysis experiments. Investigation of the electrochemical behaviour of tungsten oxides show the first step as an irreversible change transfer of W(VI) to W(0), followed by an irreversible chemical reation with formation insoluble in carbamide melts, the lower oxidation state of tungsten oxide. When studying the electrochemical behaviour of tungsten oxide and its compounds (Li2WO4, Na2WO4, and K2WO4) in molten carbamide, it can be concluded that maximum limiting currents are typical of the (NH2)2CO-Na2WO4 system. Micron W coatings on nickel cathodes have been obtained by the electrolysis of the molten system (NH2)2CO-Na2WO4 at current densities of 10-20 mA/cm2.
Keywords:
Electrochemical; Moltensalt; Tungsten;References:
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10. p. 2483-2490.
[2] Tumanova N.Kh., Devyatkin C.V. Boiko O.I. 2004. Refractory metals electrochemistry
in ion and ion–organic melts. In: Ukrainian Chemical Journal. Volume 7/8. p. 78-84.
[3] Nicholson R.S. and Shain I. 1964. Theory of stationary electrode polarography. In:
Analytical Chemistry. Volume 36. p. 706-722.