Sufficiently high concentrations of nitrate additions to chloride (Cl−) solution resulted in the elimination of slow rise metastable pitting transients and, correspondingly, localized corrosion inhibition in Type 304L (UNS S30403) stainless steel (SS). In comparison, the nucleation frequency of sharp rise metastable pitting transients was independent of concentration. Sharp rise transients in solutions containing only were associated with the highest peak current and calculated pit current densities, 50 A/cm2 to 200 A/cm2. Thus, does not appear to inhibit pitting corrosion by reducing the current density at the incipient pit surface. To evaluate the influence of on repassivation, we developed a mathematical expression for fitting transients. In the case of sharp rise transients, the resulting parameters were used to generate plots of the anodic dissolution and the film growth components of the current as well as the fraction of passive film coverage with time. In comparison, the decay portion of slow rise transients could not be fit by our expression. It was concluded that, while the repassivation of sharp rise transients can be modeled as exposure of bare metal and subsequent oxide film formation, it appears that the repassivation of slow transients is governed by a different process.
Skip Nav Destination
Article navigation
1 July 2010
Research Article|
July 01 2010
Influence of Nitrate on Pit Stability in Austenitic Stainless Steel
R.S. Lillard;
R.S. Lillard
‡
*Materials Corrosion and Environmental Effects Lab, Materials Science and Technology Division, MST-6, Los Alamos National Laboratory, Los Alamos, NM 87545.
‡Corresponding author. E-mail: [email protected].
Search for other works by this author on:
G. Vasquez, Jr.;
G. Vasquez, Jr.
fn1-1_3462911
**Materials Corrosion and Environmental Effects Lab, Materials Science and Technology Division, MST-6, Los Alamos National Laboratory, Los Alamos, NM 87545.
Search for other works by this author on:
D.F. Bahr
D.F. Bahr
***School of Mechanical and Materials Engineering, Washington State University, PO Box 642920, Pullman, WA 99164.
Search for other works by this author on:
‡Corresponding author. E-mail: [email protected].
Present address: Mechanical and Materials Engineering Division, Southwest Research Institute, San Antonio, TX 78238.
Online ISSN: 1938-159X
Print ISSN: 0010-9312
NACE International
2010
CORROSION (2010) 66 (7): 075004-1–075004-12.
Citation
R.S. Lillard, G. Vasquez, D.F. Bahr; Influence of Nitrate on Pit Stability in Austenitic Stainless Steel. CORROSION 1 July 2010; 66 (7): 075004–1–075004–12. https://doi.org/10.5006/1.3462911
Download citation file:
Citing articles via
Suggested Reading
Influence and Mechanism of SO42− Ions on the Pitting Corrosion of Boiler Water-Wall Tubes
CORROSION (January,2012)
Inhibition of Aluminum 7075 Alloy Corrosion by the Concerted Action of Nitrate and Oxalate Salts
CORROSION (November,1991)
Role of Thiosulfate in the Corrosion of Steels: A Review
CORROSION (June,2015)