Berlin 2005 – wissenschaftliches Programm
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DY: Dynamik und Statistische Physik
DY 44: Growth and Fracture
DY 44.9: Vortrag
Dienstag, 8. März 2005, 17:45–18:00, TU H3010
Explosive Metastable Pitting Corrosion on Stainless Steel (Theory) — •Christian Punckt1, Monika Bölscher1, Alexander Mikhailov1, John L. Hudson2, and Harm H. Rotermund1 — 1Fritz-Haber-Institut der Max-Planck-Gesellschaft, Abteilung Physikalische Chemie, Faradayweg 4-6, 14195 Berlin — 2University of Virginia, Dept. of Chemical Engineering, 102 Engineer’s Way, Charlottesville, VA
Stainless steel is an alloy specially designed to be corrosion resistant. This resistance is due to a protective oxide layer, which forms naturally on the metal surface in the presence of oxygen. However, all stainless steels are susceptible to pitting corrosion, which can lead to severe damage of the material. It is observed, that pitting corrosion is preceded by the appearance of metastable pits. When metastable pits occur, the surface is eroded locally but the reaction stops after a few seconds and the oxide layer rebuilds. The onset of metastable pitting corrosion is investigated theoretically and experimentally.
Numerical simulations based on a new phenomenological model lead to a fresh understanding of the onset of corrosion. Metastable pits interact with each other and an explosive autocatalytic growth of the number of pits is found. This approach is supported by experimental results.