Electrochemical study of the passive behaviour of Ni-Cr alloys in a borate solution

A mixed-conduction model approach

Martin Bojinov, Gunilla Fabricius, Petri Kinnunen (Corresponding Author), Timo Laitinen, Kari Mäkelä, Timo Saario

Research output: Contribution to journalArticleScientificpeer-review

72 Citations (Scopus)

Abstract

This paper discusses the application of the recently introduced mixed-conduction model (MCM) to describe the electrochemical behaviour of anodic films formed on Ni–Cr alloys. The MCM emphasises the coupling between the spatial distribution of ionic point defects in the film and the electronic conductivity of the film. The basic concepts of the MCM are introduced, and equations for the concentration profiles of ionic defects, for the conductivity and for the ac response of the film are derived. The experimental part of this work consist of characterising the anodic behaviour of Ni–Cr alloys, pure Ni and pure Cr in 0.1 M Na2B4O7 solution (pH 9.3) at ambient temperature using rotating disc and cyclic voltammetry, contact electric resistance (CER) and electrochemical impedance spectroscopic (EIS) techniques. The experiments indicate that the film on a Ni–20%Cr alloy resembles that on pure Cr, whereas similarities can be found between the film on Ni–10%Cr alloy and pure Ni. The conductivity of the passive film formed on Ni–Cr alloys can be concluded to be based on the spatial and potential distribution of the valence states of Ni and Cr in the film. In spite of several simplifying assumptions used in the simulations, a qualitative agreement between the theory and experimental data was achieved.

Original languageEnglish
Pages (from-to)29-44
Number of pages16
JournalJournal of Electroanalytical Chemistry
Volume504
Issue number1
DOIs
Publication statusPublished - 2001
MoE publication typeA1 Journal article-refereed

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Borates
Electric contacts
Rotating disks
Point defects
Spatial distribution
Cyclic voltammetry
Defects

Cite this

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title = "Electrochemical study of the passive behaviour of Ni-Cr alloys in a borate solution: A mixed-conduction model approach",
abstract = "This paper discusses the application of the recently introduced mixed-conduction model (MCM) to describe the electrochemical behaviour of anodic films formed on Ni–Cr alloys. The MCM emphasises the coupling between the spatial distribution of ionic point defects in the film and the electronic conductivity of the film. The basic concepts of the MCM are introduced, and equations for the concentration profiles of ionic defects, for the conductivity and for the ac response of the film are derived. The experimental part of this work consist of characterising the anodic behaviour of Ni–Cr alloys, pure Ni and pure Cr in 0.1 M Na2B4O7 solution (pH 9.3) at ambient temperature using rotating disc and cyclic voltammetry, contact electric resistance (CER) and electrochemical impedance spectroscopic (EIS) techniques. The experiments indicate that the film on a Ni–20{\%}Cr alloy resembles that on pure Cr, whereas similarities can be found between the film on Ni–10{\%}Cr alloy and pure Ni. The conductivity of the passive film formed on Ni–Cr alloys can be concluded to be based on the spatial and potential distribution of the valence states of Ni and Cr in the film. In spite of several simplifying assumptions used in the simulations, a qualitative agreement between the theory and experimental data was achieved.",
author = "Martin Bojinov and Gunilla Fabricius and Petri Kinnunen and Timo Laitinen and Kari M{\"a}kel{\"a} and Timo Saario",
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language = "English",
volume = "504",
pages = "29--44",
journal = "Journal of Electroanalytical Chemistry",
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Electrochemical study of the passive behaviour of Ni-Cr alloys in a borate solution : A mixed-conduction model approach. / Bojinov, Martin; Fabricius, Gunilla; Kinnunen, Petri (Corresponding Author); Laitinen, Timo; Mäkelä, Kari; Saario, Timo.

In: Journal of Electroanalytical Chemistry, Vol. 504, No. 1, 2001, p. 29-44.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Electrochemical study of the passive behaviour of Ni-Cr alloys in a borate solution

T2 - A mixed-conduction model approach

AU - Bojinov, Martin

AU - Fabricius, Gunilla

AU - Kinnunen, Petri

AU - Laitinen, Timo

AU - Mäkelä, Kari

AU - Saario, Timo

N1 - Project code: V1SU00115

PY - 2001

Y1 - 2001

N2 - This paper discusses the application of the recently introduced mixed-conduction model (MCM) to describe the electrochemical behaviour of anodic films formed on Ni–Cr alloys. The MCM emphasises the coupling between the spatial distribution of ionic point defects in the film and the electronic conductivity of the film. The basic concepts of the MCM are introduced, and equations for the concentration profiles of ionic defects, for the conductivity and for the ac response of the film are derived. The experimental part of this work consist of characterising the anodic behaviour of Ni–Cr alloys, pure Ni and pure Cr in 0.1 M Na2B4O7 solution (pH 9.3) at ambient temperature using rotating disc and cyclic voltammetry, contact electric resistance (CER) and electrochemical impedance spectroscopic (EIS) techniques. The experiments indicate that the film on a Ni–20%Cr alloy resembles that on pure Cr, whereas similarities can be found between the film on Ni–10%Cr alloy and pure Ni. The conductivity of the passive film formed on Ni–Cr alloys can be concluded to be based on the spatial and potential distribution of the valence states of Ni and Cr in the film. In spite of several simplifying assumptions used in the simulations, a qualitative agreement between the theory and experimental data was achieved.

AB - This paper discusses the application of the recently introduced mixed-conduction model (MCM) to describe the electrochemical behaviour of anodic films formed on Ni–Cr alloys. The MCM emphasises the coupling between the spatial distribution of ionic point defects in the film and the electronic conductivity of the film. The basic concepts of the MCM are introduced, and equations for the concentration profiles of ionic defects, for the conductivity and for the ac response of the film are derived. The experimental part of this work consist of characterising the anodic behaviour of Ni–Cr alloys, pure Ni and pure Cr in 0.1 M Na2B4O7 solution (pH 9.3) at ambient temperature using rotating disc and cyclic voltammetry, contact electric resistance (CER) and electrochemical impedance spectroscopic (EIS) techniques. The experiments indicate that the film on a Ni–20%Cr alloy resembles that on pure Cr, whereas similarities can be found between the film on Ni–10%Cr alloy and pure Ni. The conductivity of the passive film formed on Ni–Cr alloys can be concluded to be based on the spatial and potential distribution of the valence states of Ni and Cr in the film. In spite of several simplifying assumptions used in the simulations, a qualitative agreement between the theory and experimental data was achieved.

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DO - 10.1016/S0022-0728(01)00423-5

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JO - Journal of Electroanalytical Chemistry

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SN - 1572-6657

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