Cooperative and synergistic corrosion inhibition of AA 7075-T6 by praseodymium and CaSO4

Pitichon Klomjit, Rudolph G. Buchheit

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

In a primer coating system used in aerospace applications to protect aluminum alloy substrate, praseodymium is added as corrosion inhibitors while CaSO4 is primarily added as filler materials. The interaction of Pr and CaSO4 is unknown. The goal of this study is to characterize any cooperative or synergistic inhibition between these two. Cooperative inhibition can be defined when one inhibitor enhances inhibiting effect of the other that already has inhibiting ability. Synergistic inhibition can be defined when one inhibitor activates the inhibiting effect of the other that originally does not inhibit. Optical profilometry, electrochemical techniques and X-ray photoelectron spectroscopy were used to characterize corrosion results. The results showed that several pit parameters will affirm the inhibition effect. Electrochemical results cannot always detect modest corrosion inhibitors. Cooperative inhibition was detected in pH 5 while synergistic inhibition was observed in pH 8. Synergistic inhibition occurs because SO42- helps with gelation of Pr to passivate the surface.

Original languageEnglish
Pages (from-to)365-380
Number of pages16
JournalCorrosion Reviews
Volume38
Issue number4
DOIs
StatePublished - Aug 1 2020

Bibliographical note

Publisher Copyright:
© 2020 Walter de Gruyter GmbH, Berlin/Boston 2020.

Funding

Research funding: This material is based on research sponsored by the U.S. Air Force Academy under agreement number FA7000-10-2-0012 and financial support is gratefully acknowledged. The contents of this presentation do not necessarily reflect the position or policy of the U.S. Government and no official endorsement should be inferred.

FundersFunder number
U.S. Air Force AcademyFA7000-10-2-0012

    Keywords

    • Aluminum alloys
    • Calcium sulfate
    • Inhibitors
    • Localized corrosion
    • Praseodymium
    • Synergy

    ASJC Scopus subject areas

    • General Chemistry
    • General Chemical Engineering
    • General Materials Science

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