Oxidative dissolution and anion-assisted solubilisation in the transpassive state of nickel-chromium alloys

Iva Betova, Martin Bojinov (Corresponding Author), Tzvety Tzvetkoff

Research output: Contribution to journalArticleScientificpeer-review

16 Citations (Scopus)

Abstract

The transpassive state of pure Ni, Cr and two Ni–Cr alloys (10 and 20 wt.% Cr) in 14.8 M H3PO4 is studied by voltammetric, rotating ring-disc electrode and impedance spectroscopic measurements. The results indicate that the rate of transpassive dissolution of the alloys in a major part of the transpassive range is higher than the rate of this process for both pure metals. A kinetic model retaining the essential features of the corresponding models for the pure metals proposed in the literature has been found to reproduce both the steady-state current versus potential curves and the ac impedance spectra in the transpassive range. The parameters of the model are determined by a fitting procedure and the relevance of their values for the relative importance of two possible pathways in the transpassive state—oxidative dissolution and anion-assisted solubilisation—are discussed.

Original languageEnglish
Pages (from-to)2295-2306
Number of pages12
JournalElectrochimica Acta
Volume49
Issue number14
DOIs
Publication statusPublished - 2004
MoE publication typeA1 Journal article-refereed

Fingerprint

Chromium Alloys
Chromium alloys
Nickel alloys
Anions
Dissolution
Negative ions
Metals
Electrodes
Kinetics

Keywords

  • nickel-chromium alloys
  • transpassive dissolution
  • surface reactions
  • impedance spectroscopy
  • kinetic model

Cite this

Betova, Iva ; Bojinov, Martin ; Tzvetkoff, Tzvety. / Oxidative dissolution and anion-assisted solubilisation in the transpassive state of nickel-chromium alloys. In: Electrochimica Acta. 2004 ; Vol. 49, No. 14. pp. 2295-2306.
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abstract = "The transpassive state of pure Ni, Cr and two Ni–Cr alloys (10 and 20 wt.{\%} Cr) in 14.8 M H3PO4 is studied by voltammetric, rotating ring-disc electrode and impedance spectroscopic measurements. The results indicate that the rate of transpassive dissolution of the alloys in a major part of the transpassive range is higher than the rate of this process for both pure metals. A kinetic model retaining the essential features of the corresponding models for the pure metals proposed in the literature has been found to reproduce both the steady-state current versus potential curves and the ac impedance spectra in the transpassive range. The parameters of the model are determined by a fitting procedure and the relevance of their values for the relative importance of two possible pathways in the transpassive state—oxidative dissolution and anion-assisted solubilisation—are discussed.",
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Oxidative dissolution and anion-assisted solubilisation in the transpassive state of nickel-chromium alloys. / Betova, Iva; Bojinov, Martin (Corresponding Author); Tzvetkoff, Tzvety.

In: Electrochimica Acta, Vol. 49, No. 14, 2004, p. 2295-2306.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Oxidative dissolution and anion-assisted solubilisation in the transpassive state of nickel-chromium alloys

AU - Betova, Iva

AU - Bojinov, Martin

AU - Tzvetkoff, Tzvety

N1 - Project code: G4SU00051

PY - 2004

Y1 - 2004

N2 - The transpassive state of pure Ni, Cr and two Ni–Cr alloys (10 and 20 wt.% Cr) in 14.8 M H3PO4 is studied by voltammetric, rotating ring-disc electrode and impedance spectroscopic measurements. The results indicate that the rate of transpassive dissolution of the alloys in a major part of the transpassive range is higher than the rate of this process for both pure metals. A kinetic model retaining the essential features of the corresponding models for the pure metals proposed in the literature has been found to reproduce both the steady-state current versus potential curves and the ac impedance spectra in the transpassive range. The parameters of the model are determined by a fitting procedure and the relevance of their values for the relative importance of two possible pathways in the transpassive state—oxidative dissolution and anion-assisted solubilisation—are discussed.

AB - The transpassive state of pure Ni, Cr and two Ni–Cr alloys (10 and 20 wt.% Cr) in 14.8 M H3PO4 is studied by voltammetric, rotating ring-disc electrode and impedance spectroscopic measurements. The results indicate that the rate of transpassive dissolution of the alloys in a major part of the transpassive range is higher than the rate of this process for both pure metals. A kinetic model retaining the essential features of the corresponding models for the pure metals proposed in the literature has been found to reproduce both the steady-state current versus potential curves and the ac impedance spectra in the transpassive range. The parameters of the model are determined by a fitting procedure and the relevance of their values for the relative importance of two possible pathways in the transpassive state—oxidative dissolution and anion-assisted solubilisation—are discussed.

KW - nickel-chromium alloys

KW - transpassive dissolution

KW - surface reactions

KW - impedance spectroscopy

KW - kinetic model

U2 - 10.1016/j.electacta.2004.01.010

DO - 10.1016/j.electacta.2004.01.010

M3 - Article

VL - 49

SP - 2295

EP - 2306

JO - Electrochimica Acta

JF - Electrochimica Acta

SN - 0013-4686

IS - 14

ER -