Passivation mechanism of iron in concentrated phosphoric acid

Martin Bojinov (Corresponding Author), Iva Betova, Gunilla Fabricius, Timo Laitinen, R. Raicheff

Research output: Contribution to journalArticleScientificpeer-review

23 Citations (Scopus)

Abstract

The passivation process of pure iron in 85% H3PO4 was studied by conventional and rotating ring-disk voltammetry, impedance spectroscopy, and dc contact electric resistance (CER) techniques. The evolution of the film resistance as a function of potential in the passivation domain, demonstrated that the passivation of iron is most probably due to an adsorbed layer or a fairly conductive precursor film. Rotating ring-disk studies indicated the release of both soluble Fe(II) and Fe(III) in the passivation domain, a peak in the release of Fe(III) coinciding with the active-to-passive transition. Impedance spectra of Fe passivation, with a peculiar shape circling the origin of the complex plane, were found to be qualitatively analogous to those for a range of metals in concentrated acidic solutions. A kinetic model is proposed which reproduces quantitatively the steady-state and ac impedance results in the passivation region.

Original languageEnglish
Pages (from-to)58-65
Number of pages8
JournalJournal of Electroanalytical Chemistry
Volume475
Issue number1
DOIs
Publication statusPublished - 1999
MoE publication typeA1 Journal article-refereed

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Phosphoric acid
Passivation
Iron
Electric contacts
Voltammetry
phosphoric acid
Metals
Spectroscopy
Kinetics

Cite this

Bojinov, M., Betova, I., Fabricius, G., Laitinen, T., & Raicheff, R. (1999). Passivation mechanism of iron in concentrated phosphoric acid. Journal of Electroanalytical Chemistry, 475(1), 58-65. https://doi.org/10.1016/S0022-0728(99)00343-5
Bojinov, Martin ; Betova, Iva ; Fabricius, Gunilla ; Laitinen, Timo ; Raicheff, R. / Passivation mechanism of iron in concentrated phosphoric acid. In: Journal of Electroanalytical Chemistry. 1999 ; Vol. 475, No. 1. pp. 58-65.
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abstract = "The passivation process of pure iron in 85{\%} H3PO4 was studied by conventional and rotating ring-disk voltammetry, impedance spectroscopy, and dc contact electric resistance (CER) techniques. The evolution of the film resistance as a function of potential in the passivation domain, demonstrated that the passivation of iron is most probably due to an adsorbed layer or a fairly conductive precursor film. Rotating ring-disk studies indicated the release of both soluble Fe(II) and Fe(III) in the passivation domain, a peak in the release of Fe(III) coinciding with the active-to-passive transition. Impedance spectra of Fe passivation, with a peculiar shape circling the origin of the complex plane, were found to be qualitatively analogous to those for a range of metals in concentrated acidic solutions. A kinetic model is proposed which reproduces quantitatively the steady-state and ac impedance results in the passivation region.",
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Bojinov, M, Betova, I, Fabricius, G, Laitinen, T & Raicheff, R 1999, 'Passivation mechanism of iron in concentrated phosphoric acid', Journal of Electroanalytical Chemistry, vol. 475, no. 1, pp. 58-65. https://doi.org/10.1016/S0022-0728(99)00343-5

Passivation mechanism of iron in concentrated phosphoric acid. / Bojinov, Martin (Corresponding Author); Betova, Iva; Fabricius, Gunilla; Laitinen, Timo; Raicheff, R.

In: Journal of Electroanalytical Chemistry, Vol. 475, No. 1, 1999, p. 58-65.

Research output: Contribution to journalArticleScientificpeer-review

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T1 - Passivation mechanism of iron in concentrated phosphoric acid

AU - Bojinov, Martin

AU - Betova, Iva

AU - Fabricius, Gunilla

AU - Laitinen, Timo

AU - Raicheff, R.

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AB - The passivation process of pure iron in 85% H3PO4 was studied by conventional and rotating ring-disk voltammetry, impedance spectroscopy, and dc contact electric resistance (CER) techniques. The evolution of the film resistance as a function of potential in the passivation domain, demonstrated that the passivation of iron is most probably due to an adsorbed layer or a fairly conductive precursor film. Rotating ring-disk studies indicated the release of both soluble Fe(II) and Fe(III) in the passivation domain, a peak in the release of Fe(III) coinciding with the active-to-passive transition. Impedance spectra of Fe passivation, with a peculiar shape circling the origin of the complex plane, were found to be qualitatively analogous to those for a range of metals in concentrated acidic solutions. A kinetic model is proposed which reproduces quantitatively the steady-state and ac impedance results in the passivation region.

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