The mechanism of the transpassive dissolution of chromium in acidic sulfate solutions

Martin Bojinov; Gunilla Fabricius; Timo Laitinen; Timo Saario

doi:10.1149/1.1838595

The mechanism of the transpassive dissolution of chromium in acidic sulfate solutions

Martin Bojinov, Gunilla Fabricius, Timo Laitinen, Timo Saario

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Abstract

The transpassivity of chromium in 1 M sulfate solutions (pH 0 and 5) was studied by steady‐state polarization, rotating ring‐disk electrode voltammetry, and impedance spectroscopy in combination with the contact electric resistance technique.
Ring‐disk electrode measurements in the transpassive region indicated the dissolution of Cr mainly as Cr(VI) and partly as Cr(III). The conductivity of the anodic film strongly increased in the transpassive potential range, probably due to the formation of Cr(VI) species.
A kinetic model for the transpassive process was advanced to explain the observed experimental features. It comprises two dissolution paths of Cr as Cr(VI) and one as Cr(III). The formation of a Cr(IV) intermediate and a continuous change in the valence state of Cr at the film/solution interface are considered. Kinetic equations for both steady state and impedance response were derived and compared to experimental results to determine the reaction rate constants.

Original language	English
Pages (from-to)	2043-2050
Journal	Journal of the Electrochemical Society
Volume	145
Issue number	6
DOIs	https://doi.org/10.1149/1.1838595
Publication status	Published - 1998
MoE publication type	A1 Journal article-refereed

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Bojinov, M., Fabricius, G., Laitinen, T., & Saario, T. (1998). The mechanism of the transpassive dissolution of chromium in acidic sulfate solutions. Journal of the Electrochemical Society, 145(6), 2043-2050. https://doi.org/10.1149/1.1838595

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abstract = "The transpassivity of chromium in 1 M sulfate solutions (pH 0 and 5) was studied by steady‐state polarization, rotating ring‐disk electrode voltammetry, and impedance spectroscopy in combination with the contact electric resistance technique. Ring‐disk electrode measurements in the transpassive region indicated the dissolution of Cr mainly as Cr(VI) and partly as Cr(III). The conductivity of the anodic film strongly increased in the transpassive potential range, probably due to the formation of Cr(VI) species. A kinetic model for the transpassive process was advanced to explain the observed experimental features. It comprises two dissolution paths of Cr as Cr(VI) and one as Cr(III). The formation of a Cr(IV) intermediate and a continuous change in the valence state of Cr at the film/solution interface are considered. Kinetic equations for both steady state and impedance response were derived and compared to experimental results to determine the reaction rate constants.",

author = "Martin Bojinov and Gunilla Fabricius and Timo Laitinen and Timo Saario",

year = "1998",

doi = "10.1149/1.1838595",

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T1 - The mechanism of the transpassive dissolution of chromium in acidic sulfate solutions

AU - Bojinov, Martin

AU - Fabricius, Gunilla

AU - Laitinen, Timo

AU - Saario, Timo

PY - 1998

Y1 - 1998

N2 - The transpassivity of chromium in 1 M sulfate solutions (pH 0 and 5) was studied by steady‐state polarization, rotating ring‐disk electrode voltammetry, and impedance spectroscopy in combination with the contact electric resistance technique. Ring‐disk electrode measurements in the transpassive region indicated the dissolution of Cr mainly as Cr(VI) and partly as Cr(III). The conductivity of the anodic film strongly increased in the transpassive potential range, probably due to the formation of Cr(VI) species. A kinetic model for the transpassive process was advanced to explain the observed experimental features. It comprises two dissolution paths of Cr as Cr(VI) and one as Cr(III). The formation of a Cr(IV) intermediate and a continuous change in the valence state of Cr at the film/solution interface are considered. Kinetic equations for both steady state and impedance response were derived and compared to experimental results to determine the reaction rate constants.

AB - The transpassivity of chromium in 1 M sulfate solutions (pH 0 and 5) was studied by steady‐state polarization, rotating ring‐disk electrode voltammetry, and impedance spectroscopy in combination with the contact electric resistance technique. Ring‐disk electrode measurements in the transpassive region indicated the dissolution of Cr mainly as Cr(VI) and partly as Cr(III). The conductivity of the anodic film strongly increased in the transpassive potential range, probably due to the formation of Cr(VI) species. A kinetic model for the transpassive process was advanced to explain the observed experimental features. It comprises two dissolution paths of Cr as Cr(VI) and one as Cr(III). The formation of a Cr(IV) intermediate and a continuous change in the valence state of Cr at the film/solution interface are considered. Kinetic equations for both steady state and impedance response were derived and compared to experimental results to determine the reaction rate constants.

U2 - 10.1149/1.1838595

DO - 10.1149/1.1838595

M3 - Article

VL - 145

SP - 2043

EP - 2050

JO - Journal of the Electrochemical Society

JF - Journal of the Electrochemical Society

SN - 0013-4651

IS - 6

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