The transpassive dissolution mechanism of highly alloyed stainless steels: II. Effect of pH and solution anion on the kinetics

Iva Betova, Martin Bojinov (Corresponding Author), Timo Laitinen, Kari Mäkelä, Pekka Pohjanne, Timo Saario

Research output: Contribution to journalArticleScientificpeer-review

40 Citations (Scopus)

Abstract

The effect of pH and solution anion on the kinetics of transpassive dissolution of highly alloyed austenitic stainless steels (AISI 904L, 254SMO and 654SMO) was studied by a combination of electrochemical techniques. The experiments were performed in 0.5 M sulphate and 0.5 M chloride solutions, and in an equimolar mixture of the two. The transpassive dissolution was found to start at higher potentials in solutions with higher pH. The rate of transpassive dissolution was shown to decrease with increasing pH and to be the lowest in chloride solutions and the highest in sulphate electrolytes. The steady-state current vs. potential curves and the impedance spectra of the studied materials in the transpassive potential region were found to be consistent with a proposed kinetic model. The model describes the process as dissolution of Cr as Cr(VI) and Fe as Fe(III) through the anodic oxide film via parallel reaction paths. The kinetic parameters of the model in solutions with different pH values and different anions were determined. The role of pH and solution anion in the transpassive dissolution process is discussed in relation to changes induced by these parameters in the composition of the anodic passive film. The factors determining the efficiency of Fe as a secondary passivating agent are also considered.
Original languageEnglish
Pages (from-to)2699-2723
JournalCorrosion Science
Volume44
Issue number12
DOIs
Publication statusPublished - 2002
MoE publication typeA1 Journal article-refereed

Fingerprint

Stainless Steel
Anions
Dissolution
Negative ions
Stainless steel
Kinetics
Sulfates
Chlorides
Austenitic stainless steel
Kinetic parameters
Electrolytes
Oxide films
Chemical analysis
Experiments

Keywords

  • Stainless steel
  • EIS
  • RRDE
  • Modelling studies
  • Transpassivity
  • Kinetic parameters

Cite this

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title = "The transpassive dissolution mechanism of highly alloyed stainless steels: II. Effect of pH and solution anion on the kinetics",
abstract = "The effect of pH and solution anion on the kinetics of transpassive dissolution of highly alloyed austenitic stainless steels (AISI 904L, 254SMO and 654SMO) was studied by a combination of electrochemical techniques. The experiments were performed in 0.5 M sulphate and 0.5 M chloride solutions, and in an equimolar mixture of the two. The transpassive dissolution was found to start at higher potentials in solutions with higher pH. The rate of transpassive dissolution was shown to decrease with increasing pH and to be the lowest in chloride solutions and the highest in sulphate electrolytes. The steady-state current vs. potential curves and the impedance spectra of the studied materials in the transpassive potential region were found to be consistent with a proposed kinetic model. The model describes the process as dissolution of Cr as Cr(VI) and Fe as Fe(III) through the anodic oxide film via parallel reaction paths. The kinetic parameters of the model in solutions with different pH values and different anions were determined. The role of pH and solution anion in the transpassive dissolution process is discussed in relation to changes induced by these parameters in the composition of the anodic passive film. The factors determining the efficiency of Fe as a secondary passivating agent are also considered.",
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The transpassive dissolution mechanism of highly alloyed stainless steels : II. Effect of pH and solution anion on the kinetics. / Betova, Iva; Bojinov, Martin (Corresponding Author); Laitinen, Timo; Mäkelä, Kari; Pohjanne, Pekka; Saario, Timo.

In: Corrosion Science, Vol. 44, No. 12, 2002, p. 2699-2723.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - The transpassive dissolution mechanism of highly alloyed stainless steels

T2 - II. Effect of pH and solution anion on the kinetics

AU - Betova, Iva

AU - Bojinov, Martin

AU - Laitinen, Timo

AU - Mäkelä, Kari

AU - Pohjanne, Pekka

AU - Saario, Timo

PY - 2002

Y1 - 2002

N2 - The effect of pH and solution anion on the kinetics of transpassive dissolution of highly alloyed austenitic stainless steels (AISI 904L, 254SMO and 654SMO) was studied by a combination of electrochemical techniques. The experiments were performed in 0.5 M sulphate and 0.5 M chloride solutions, and in an equimolar mixture of the two. The transpassive dissolution was found to start at higher potentials in solutions with higher pH. The rate of transpassive dissolution was shown to decrease with increasing pH and to be the lowest in chloride solutions and the highest in sulphate electrolytes. The steady-state current vs. potential curves and the impedance spectra of the studied materials in the transpassive potential region were found to be consistent with a proposed kinetic model. The model describes the process as dissolution of Cr as Cr(VI) and Fe as Fe(III) through the anodic oxide film via parallel reaction paths. The kinetic parameters of the model in solutions with different pH values and different anions were determined. The role of pH and solution anion in the transpassive dissolution process is discussed in relation to changes induced by these parameters in the composition of the anodic passive film. The factors determining the efficiency of Fe as a secondary passivating agent are also considered.

AB - The effect of pH and solution anion on the kinetics of transpassive dissolution of highly alloyed austenitic stainless steels (AISI 904L, 254SMO and 654SMO) was studied by a combination of electrochemical techniques. The experiments were performed in 0.5 M sulphate and 0.5 M chloride solutions, and in an equimolar mixture of the two. The transpassive dissolution was found to start at higher potentials in solutions with higher pH. The rate of transpassive dissolution was shown to decrease with increasing pH and to be the lowest in chloride solutions and the highest in sulphate electrolytes. The steady-state current vs. potential curves and the impedance spectra of the studied materials in the transpassive potential region were found to be consistent with a proposed kinetic model. The model describes the process as dissolution of Cr as Cr(VI) and Fe as Fe(III) through the anodic oxide film via parallel reaction paths. The kinetic parameters of the model in solutions with different pH values and different anions were determined. The role of pH and solution anion in the transpassive dissolution process is discussed in relation to changes induced by these parameters in the composition of the anodic passive film. The factors determining the efficiency of Fe as a secondary passivating agent are also considered.

KW - Stainless steel

KW - EIS

KW - RRDE

KW - Modelling studies

KW - Transpassivity

KW - Kinetic parameters

U2 - 10.1016/S0010-938X(02)00074-4

DO - 10.1016/S0010-938X(02)00074-4

M3 - Article

VL - 44

SP - 2699

EP - 2723

JO - Corrosion Science

JF - Corrosion Science

SN - 0010-938X

IS - 12

ER -