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The nature of the surface film on steel treated with cerium and lanthanum cinnamate based corrosion inhibitors

journal contribution
posted on 01.02.2006, 00:00 authored by F Blin, S Leary, G Deacon, P Junk, Maria ForsythMaria Forsyth
The corrosion inhibition mechanisms of new cerium and lanthanum cinnamate based compounds have been investigated through the surface characterisation of the steel exposed to NaCl solution of neutral pH. Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) spectroscopy was used to identify the nature of the deposits on the metal surface and demonstrated that after accelerated tests the corrosion product commonly observed on steel (i.e. lepidocrocite, γ-FeOOH) is absent. The cinnamate species were clearly present on the steel surface upon exposure to NaCl solution for short periods and appeared to coordinate through the iron. At longer times the Rare Earth Metal (REM) oxyhydroxide species are proposed to form as identified through the bands in the 1400–1500 cm−1 region. These latter bands have been previously assigned to carbonate species adsorbed onto REM oxyhydroxide surfaces. The protection mechanism appears to involve the adsorption of the REM–cinnamate complex followed by the hydrolysis of the REM to form a barrier oxide on the steel surface.

History

Journal

Corrosion science

Volume

48

Issue

2

Pagination

404 - 419

Publisher

Elsevier

Location

Amsterdam, The Netherlands

ISSN

0010-938X

eISSN

1879-0496

Language

eng

Publication classification

C1.1 Refereed article in a scholarly journal

Copyright notice

2005, Elsevier Ltd.