Temporal patterning of the potential induced by localized corrosion of iron passivity in acid media. Growth and breakdown of the oxide film described in terms of a point defect model

2009 ◽  
Vol 11 (39) ◽  
pp. 8841 ◽  
Author(s):  
Dimitra Sazou ◽  
Maria Pavlidou ◽  
Michael Pagitsas
Keyword(s):  
Oxide Film ◽  
Point Defect ◽  
Localized Corrosion ◽  
Temporal Patterning ◽  
Defect Model ◽  
Acid Media ◽  
Point Defect Model ◽  
Corrosion Of Iron

STUDY OF THE PASSIVITY LIMITS OF AUSTENITIC STAINLESS-STEEL IN H2S-CONTAINING BRINES USING MOTT-SCHOTTKY AND POINT DEFECT MODEL ANALYSIS

CORROSION ◽  
10.5006/3744 ◽  
2021 ◽  
Author(s):  
Raymundo Case
Keyword(s):  
Stainless Steel ◽  
Point Defect ◽  
Electron Donor ◽  
Alternate Current ◽  
Passive Layer ◽  
Localized Corrosion ◽  
Defect Model ◽  
Point Defect Model ◽  
Metastable Pitting ◽  
Donor Species

The objective of the study is to correlate the effects of H<sub>2</sub>S, and Cl<sup>-</sup> concentration on the passivity limits and the onset of localized corrosion, in UNS S31603 stainless steel by evaluating the changes in the semiconducting behavior exhibited by the passive layer. The study is accomplished experimentally by using a combination of direct and alternate current electrochemical methods, to study the passive layer formed by the stainless steel, in equilibrium with a gas phase at 2.8 MPa (400 psi) containing up to 60% mol of H<sub>2</sub>S (bal. CO<sub>2</sub>) at 25○</sup>C. The results obtained using the Mott-Schottky analysis indicate that the decrease of the passive layer stability formed on the UNS S31603 stainless steel is consistent with the increase in the electron donor carrier density. This is observed as the consequence of the effect of Cl<sup>-</sup> and H<sub>2</sub>S. In this context, the Cl<sup>-</sup> content in the brine was found to exert a larger effect than the H<sub>2</sub>S activity. The correlation with the evaluation of the passive layer using the Point Defect model suggest that both the polarizability and the rate of annihilation of the cation vacancies at the metal / film interface increase with the H<sub>2</sub>S content in the environment. This behavior can explain the increased content of Cl<sup>-</sup> and sulfides as main electron donor species, also the observable increase in the passive layer susceptibility to both stable and metastable pitting.

Non-equilibrium point defect model for time-dependent passivation of metal surfaces

2001 ◽  
Vol 46 (22) ◽  
pp. 3387-3396 ◽  
Author(s):  
Balaji Krishnamurthy ◽  
Ralph E. White ◽  
Harry J. Ploehn
Keyword(s):  
Equilibrium Point ◽  
Point Defect ◽  
Metal Surfaces ◽  
Time Dependent ◽  
Defect Model ◽  
Point Defect Model ◽  
Non Equilibrium

New evidence for the point defect model of ion transport in glasses

2002 ◽  
Vol 4 (14) ◽  
pp. 3232-3236 ◽  
Author(s):  
H. Jain ◽  
A. Sharma
Keyword(s):  
Ion Transport ◽  
Point Defect ◽  
Defect Model ◽  
Point Defect Model ◽  
New Evidence

Electrochemical Behavior of Lithium in Alkaline Aqueous Electrolytes. II. Point Defect Model

1999 ◽  
Vol 146 (4) ◽  
pp. 1326-1335 ◽  
Author(s):  
Osvaldo Pensado‐Rodriguez ◽  
José R. Flores ◽  
Mirna Urquidi‐Macdonald ◽  
Digby D. Macdonald
Keyword(s):  
Point Defect ◽  
Electrochemical Behavior ◽  
Aqueous Electrolytes ◽  
Defect Model ◽  
Point Defect Model

Point defect model and corrosion of anodic oxide coatings on Ti–6Al–4V

2008 ◽  
Vol 50 (6) ◽  
pp. 1521-1529 ◽  
Author(s):  
R. Narayanan ◽  
S.K. Seshadri
Keyword(s):  
Point Defect ◽  
Anodic Oxide ◽  
Oxide Coatings ◽  
Defect Model ◽  
Point Defect Model

In situ X-ray Reflectivity Study of Oxidation Kinetics in Iron and Stainless steel

2004 ◽  
Vol 840 ◽  
Author(s):  
D. H. Kim ◽  
S. S. Kim ◽  
H. H. Lee ◽  
H. W. Jang ◽  
J. W. Kim ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Electric Field ◽  
Point Defect ◽  
Oxide Films ◽  
Borate Buffer Solution ◽  
Applied Potential ◽  
Defect Model ◽  
Point Defect Model ◽  
X Ray

ABSTRACTIn situ specular x-ray reflectivity was applied to study the growth kinetics of passive oxide films on iron and stainless steel substrates in pH 8.4 borate buffer solution. Under electrical potential from 0 to 800 mV, the growth rate of oxide films decreases exponentially in thickness following the direct logarithmic growth law predicted in the point defect model. The electric field in the oxide on iron is independent of the applied potentials consistent with the point defect model. In stainless steel, however, the electric field depends strongly on the applied potential indicating that the oxide properties change as the applied potential varies.

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