Carbon steel passivity examined in alkaline solutions: The effect of chloride and nitrite ions
By M. Valcarce, M. Vazquez. 2008
182 citations recorded by the source corpus.
Abstract The effect of chloride and nitrite ions on the passivity of steel in alkaline solutions was investigated. Four nitrite dosages were tested, resulting in various nitrite/chloride ratios. The behavior of steel was evaluated on electrodes aged during 1 and 90 days, measuring electrochemical parameters such as the corrosion, pitting and repassivation potentials, the corrosion current density, the weight loss and performing electrochemical impedance spectra. The presence of 0.8 mol l −1 of chloride induced pitting only under polarization and when the chloride/hydroxyl ratio was not less than one. Nitrite ions behave as effective inhibitors of pit propagation for all the concentrations tested (0.2–0.8 mol l −1 ). A nitrite/chloride ratio of 0.25 induces complete surface repassivation. Nevertheless, at open circuit potential, the high alkalinity guarantees passivation even in the presence of chlorides. In the event that the passive layer is damaged and pitting can be initiated, nitrite ions are effective in inhibiting pit propagation.
Subfields: Civil and Structural Engineering, Materials Chemistry, Metals and Alloys
View Paper: https://www.semanticscholar.org/paper/f7f6e1820419723ba94681846d09cfd6c244babf
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In Civil and Structural Engineering
In Materials Chemistry
Citations in the corpus
- Phosphate ions as corrosion inhibitors for reinforcement steel in chloride-rich environments (2013, background): “In the absence of inhibitor, a depressed loop with two time constants in the Bode plot indicates the development of a surface layer, which in this case is the passive layer [9, 12, 40].”