Transpassive dissolution mechanism of ferrous alloys in phosphoric acid/acetic acid mixtures

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

Research output: Contribution to journalArticleScientificpeer-review

4 Citations (Scopus)

Abstract

The transpassive dissolution of Fe-12%Cr and Fe-25%Cr alloys in near-anhydrous phosphoric acid/acetic acid mixtures has been studied by conventional voltammetry and electrochemical impedance spectroscopy. Both steady-state and transient techniques point to two parallel pathways for the process involving oxidative dissolution of Cr as Cr(VI) and isovalent dissolution of Fe most probably mediated by an electrolyte-originating species. A simplified kinetic model of the process including only surface kinetic steps has been found to reproduce successfully both the steady-state and the small-amplitude AC response of the studied materials. The kinetic parameters of the model are determined and their relevance regarding the influence of the alloy and electrolyte composition on the relative importance of the two parallel pathways is discussed. The experimental data and model calculations indicate that the effect of acetic acid on the reaction steps related to dissolution of Fe is more significant.
Original languageEnglish
Pages (from-to)154-167
JournalJournal of Solid State Electrochemistry
Volume9
Issue number3
DOIs
Publication statusPublished - 2005
MoE publication typeA1 Journal article-refereed

Fingerprint

Iron alloys
phosphoric acid
Phosphoric acid
acetic acid
Acetic acid
Acetic Acid
dissolving
Dissolution
Electrolytes
kinetics
electrolytes
Kinetics
Voltammetry
Electrochemical impedance spectroscopy
Kinetic parameters
alternating current
impedance
Chemical analysis
spectroscopy

Keywords

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

Cite this

Betova, Iva ; Bojinov, Martin ; Tzvetkoff, Tzvety. / Transpassive dissolution mechanism of ferrous alloys in phosphoric acid/acetic acid mixtures. In: Journal of Solid State Electrochemistry. 2005 ; Vol. 9, No. 3. pp. 154-167.
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abstract = "The transpassive dissolution of Fe-12{\%}Cr and Fe-25{\%}Cr alloys in near-anhydrous phosphoric acid/acetic acid mixtures has been studied by conventional voltammetry and electrochemical impedance spectroscopy. Both steady-state and transient techniques point to two parallel pathways for the process involving oxidative dissolution of Cr as Cr(VI) and isovalent dissolution of Fe most probably mediated by an electrolyte-originating species. A simplified kinetic model of the process including only surface kinetic steps has been found to reproduce successfully both the steady-state and the small-amplitude AC response of the studied materials. The kinetic parameters of the model are determined and their relevance regarding the influence of the alloy and electrolyte composition on the relative importance of the two parallel pathways is discussed. The experimental data and model calculations indicate that the effect of acetic acid on the reaction steps related to dissolution of Fe is more significant.",
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Transpassive dissolution mechanism of ferrous alloys in phosphoric acid/acetic acid mixtures. / Betova, Iva; Bojinov, Martin (Corresponding Author); Tzvetkoff, Tzvety.

In: Journal of Solid State Electrochemistry, Vol. 9, No. 3, 2005, p. 154-167.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Transpassive dissolution mechanism of ferrous alloys in phosphoric acid/acetic acid mixtures

AU - Betova, Iva

AU - Bojinov, Martin

AU - Tzvetkoff, Tzvety

PY - 2005

Y1 - 2005

N2 - The transpassive dissolution of Fe-12%Cr and Fe-25%Cr alloys in near-anhydrous phosphoric acid/acetic acid mixtures has been studied by conventional voltammetry and electrochemical impedance spectroscopy. Both steady-state and transient techniques point to two parallel pathways for the process involving oxidative dissolution of Cr as Cr(VI) and isovalent dissolution of Fe most probably mediated by an electrolyte-originating species. A simplified kinetic model of the process including only surface kinetic steps has been found to reproduce successfully both the steady-state and the small-amplitude AC response of the studied materials. The kinetic parameters of the model are determined and their relevance regarding the influence of the alloy and electrolyte composition on the relative importance of the two parallel pathways is discussed. The experimental data and model calculations indicate that the effect of acetic acid on the reaction steps related to dissolution of Fe is more significant.

AB - The transpassive dissolution of Fe-12%Cr and Fe-25%Cr alloys in near-anhydrous phosphoric acid/acetic acid mixtures has been studied by conventional voltammetry and electrochemical impedance spectroscopy. Both steady-state and transient techniques point to two parallel pathways for the process involving oxidative dissolution of Cr as Cr(VI) and isovalent dissolution of Fe most probably mediated by an electrolyte-originating species. A simplified kinetic model of the process including only surface kinetic steps has been found to reproduce successfully both the steady-state and the small-amplitude AC response of the studied materials. The kinetic parameters of the model are determined and their relevance regarding the influence of the alloy and electrolyte composition on the relative importance of the two parallel pathways is discussed. The experimental data and model calculations indicate that the effect of acetic acid on the reaction steps related to dissolution of Fe is more significant.

KW - iron-chromium alloys

KW - transpassive dissolution

KW - surface reactions

KW - electrochemical impedance spectroscopy

KW - kinetic model

U2 - 10.1007/s10008-004-0566-1

DO - 10.1007/s10008-004-0566-1

M3 - Article

VL - 9

SP - 154

EP - 167

JO - Journal of Solid State Electrochemistry

JF - Journal of Solid State Electrochemistry

SN - 1432-8488

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ER -