The Kinetics of Nucleation of Metastable Pits on Metal Surfaces: The Point Defect Model and Its Optimization on Data Obtained on Stainless Steel, Carbon Steel, Iron, Aluminum and Alloy-22

2016 ◽  
Vol 163 (5) ◽  
pp. C156-C163 ◽  
Author(s):  
Pin Lu ◽  
George R. Engelhardt ◽  
Bruno Kursten ◽  
Digby D. Macdonald
Keyword(s):  
Stainless Steel ◽  
Carbon Steel ◽  
Point Defect ◽  
Metal Surfaces ◽  
Defect Model ◽  
Point Defect Model ◽  
Iron Aluminum ◽  
Alloy 22 ◽  
Kinetics Of

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

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.

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.

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