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Leaching behavior and corrosion Inhibition of a rare earth carboxylate incorporated epoxy coating system

journal contribution
posted on 01.01.2019, 00:00 authored by Y Peng, A E Hughes, J I Mardel, G B Deacon, P C Junk, Maria ForsythMaria Forsyth, Bruce HintonBruce Hinton, Anthony SomersAnthony Somers
© 2019 American Chemical Society. While paint coatings act as important barriers to corrosion, defects can lead to localized, rapid metal loss. The addition of corrosion inhibitors that are capable of leaching from a coating to protect the metal surface at a defect can prevent this type of corrosion. This work investigates the release and corrosion protection capabilities of two rare earth (RE) carboxylate inhibitors from an epoxy coating as an initial step to understanding their leaching behavior and interaction with the coating system. Leaching experiments were performed via inductively coupled plasma mass spectroscopy (ICP-MS) analyses of the solutions in which free-standing coatings loaded with varying concentrations of inhibitor compounds had been immersed. Inhibitor release from the epoxy coating was observed to be dependent on initial inhibitor concentration, inhibitor chemistry, and solution pH conditions. The coating systems with greater initial inhibitor loadings showed higher leaching rates, particularly in acidic environments. Following immersion, the absence of characteristic inhibitor peaks in the FTIR spectra of the coatings also confirmed leaching had taken place. Cross-sectional views of the coatings after exposure to the pH 1 environment presented a chloride infusion zone at the coating/solution interface where the inhibitor had leached out. The RE active inhibition provided by the leached RE carboxylate inhibitors was verified by exposure of a coating defect to a chloride contaminated environment.

History

Journal

ACS Applied Materials and Interfaces

Volume

11

Issue

39

Pagination

36154 - 36168

Publisher

ACS Publications

Location

Washington, D.C.

ISSN

1944-8244

eISSN

1944-8252

Language

eng

Publication classification

C1 Refereed article in a scholarly journal