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Electrochemical behaviour of dysprosium in the eutectic LiCl-KCl at W and Al electrodes

Abstract

The electrochem. behavior of DyCl3 was studied in the eutectic LiCl-KCl at different temps. The cathodic reaction can be written: Dy(III) + 3e- .tautm. Dy(0), which can be divided in 2 very close cathodic steps: Dy(III) + 1e- .tautm. Dy(II) and Dy(II) + 2e- .tautm. Dy(0). Transient electrochem. techniques, such as cyclic voltammetry, chronopotentiometry, and chronoamperometry were used to study the reaction mechanism and the transport parameters of electroactive species at a W electrode. In the eutectic LiCl-KCl, electrocrystn. of Dy seems to be the controlling electrochem. step. Chronoamperometric studies indicated instantaneous nucleation of Dy with 3 dimensional growth of the nuclei whatever the applied overpotential. Mass transport towards the electrode is a simple diffusion process, and the diffusion coeff. of the electroactive species, i.e. Dy(III), was calcd. The validity of the Arrhenius law was also verified by plotting the variation of the logarithm of the diffusion coeff. vs. 1/T. The electrode reactions of the LiCl-KCl-DyCl3 solns. at an Al wire were also studied by cyclic voltammetry and open circuit chronopotentiometry. The redox potential of the Dy(III)/Dy couple at the Al electrode was obsd. at more pos. potentials values than those at the inert electrode. This potential shift was thermodynamically analyzed by a lowering of activity of Dy in the metal phase due to the formation of intermetallic compds.

Category

Academic article

Language

English

Author(s)

  • Yolanda Castrillejo
  • Maria Reyes Bermejo
  • A.I. Barrado
  • Rafael Pardo
  • Enrique Barrado
  • Ana Maria Martinez

Affiliation

  • Unknown
  • Norwegian University of Science and Technology

Year

2005

Published in

Electrochimica Acta

ISSN

0013-4686

Publisher

Elsevier

Volume

50

Page(s)

2047 - 2057

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