|
Hokkaido University Collection of Scholarly and Academic Papers >
Graduate School of Engineering / Faculty of Engineering >
Peer-reviewed Journal Articles, etc >
The Role of Rusts in Corrosion and Corrosion Protection of Iron and Steel
| Title: | The Role of Rusts in Corrosion and Corrosion Protection of Iron and Steel |
| Authors: | Tamura, Hiroki Browse this author |
| Keywords: | Iron | | Low alloy steel | | Modeling studies | | Atmospheric corrosion | | Rust |
| Issue Date: | Jul-2008 |
| Publisher: | Pergamon |
| Journal Title: | Corrosion Science |
| Volume: | 50 |
| Issue: | 7 |
| Start Page: | 1872 |
| End Page: | 1883 |
| Publisher DOI: | 10.1016/j.corsci.2008.03.008 |
| Abstract: | The processes of atmospheric corrosion of iron and steel and the properties of corrosion products (rusts) are modeled based on a quantitative evaluation of the chemical reactions pertaining to corrosion to elucidate the conditions with which corrosion-protective rust films form. Based on the model, it is suggested that in the initial stage of corrosion, in the rusts, the pH of the aquatic system is maintained at 9.31 owing to an equilibrium with iron(II) hydroxide and the rate of air-oxidation at this pH is very fast, and that dense, self-repairing rust films form, protecting the underlying iron and steel. However, after corrosion stops, the rust film deteriorates due to the dissolution and shrinkage by aging, and the deteriorated rust film separates the anode and cathode reaction products (Fe2+ and OH- ions) to cause crevice corrosion. The air-oxidation of iron(II) in anode channels without the presence of OH- ions results in strongly acidic solutions (pH 1.41), causing acid corrosion. It is proposed that good catalysts (e.g. copper(II) and phosphate ions) accelerate the air-oxidation at low pH, delaying the crevice- and acid-corrosion stages. Further, it is argued that iron compounds with negative charges due to the non-stoichiometric proportions of the lattice oxide ions and metal ions (solid oxoanions of iron) exhibit stable cation-selective permeability even with a drop in pH. Rust films including such compounds would stop the passage of aggressive anions and act to protect iron and steel. |
| Relation: | http://www.sciencedirect.com/science/journal/0010938X |
| Type: | article (author version) |
| URI: | http://hdl.handle.net/2115/34142 |
| Appears in Collections: | 工学院・工学研究院 (Graduate School of Engineering / Faculty of Engineering) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
|
Submitter: 田村 紘基
|
