Dioxygen reduction affects surface oxide growth and dissolution on AA2024-T3

Eric J. Dufek, Jesse C. Seegmiller, Reinaldo C. Bazito, Daniel A. Buttry

Research output: Contribution to journalArticle

7 Scopus citations

Abstract

The influence of dioxygen reduction on oxide growth and dissolution at the surface of AA2024-T3 has been investigated in near-neutral, unbuffered conditions. Dioxygen reduction at Fe and Cu also was examined to compare with the behavior of intermetallic particles in AA2024-T3. Electrodes were exposed alternately to N2 -saturated or O2 -saturated 0.1 M Na2 S O4 solution in a characterized wall-jet flow cell. Limiting current densities associated with O2 reduction on Fe and Cu range between 1.5 and 2.0 mA cm-2, whereas AA2024-T3 displays significantly lower values. AA2024-T3 samples also display potential-dependent current density transients when the solution is alternated between N2 -saturated and O2 -saturated supporting electrolyte. The data show that the current density transient behavior is due to competition between interfacial etching of oxide due to high local pH, which is a result of the cathodic oxygen reduction reaction (ORR) at intermetallic particles, and anodic oxide growth on the alloy, which is driven by the electric field produced at a given potential. Scanning electron microscopy shows significant differences in oxide thickness with radial distance from the center of the jet impingement region. Energy-dispersive spectroscopic imaging reveals an increase in near-surface Cu and Fe in areas that experience high current densities.

Original languageEnglish (US)
Pages (from-to)C458-C464
JournalJournal of the Electrochemical Society
Volume154
Issue number9
DOIs
StatePublished - Aug 7 2007
Externally publishedYes

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Renewable Energy, Sustainability and the Environment
  • Surfaces, Coatings and Films
  • Electrochemistry
  • Materials Chemistry

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