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DY: Dynamik und Statistische Physik
DY 44: Growth and Fracture
DY 44.8: Vortrag
Dienstag, 8. März 2005, 17:30–17:45, TU H3010
Explosive Metastable Pitting Corrosion on Stainless Steel (Experiment) — •Monika Bölscher1, Christian Punckt1, John L. Hudson2, Alexander Mikhailov1, and Harm H. Rotermund1 — 1Fritz-Haber Institut der Max-Plank-Gesellschaft, Abteilung für physikalische Chemie, Faradayweg 4-6, 14195 Berlin — 2University of Virginia, Department of Chemical Engineering, 102 Engineers’ Way, Charlottesville, VA, USA
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.
Our experimental results show an exponential growth of surface activity and a rapid increase of the number of pits. These findings are consistent with a model, which explains the onset of corrosion as an explosive autocatalytic process.