Protection of passivated iron from corrosion in 0.1 M KClO4 with and without Cl- by coverage with a two-dimensional polymer film of carboxylate ion self-assembled monolayer

Kunitsugu Aramaki, Tadashi Shimura

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

A film of two-dimensional polymer was prepared on an iron electrode passivated in a borate buffer solution at pH 8.49, derivatized with 16-hydroxyhexadecanoate ion HO (CH2)15 CO2- and then modified with 1,2-bis(triethoxysilyl)ethane (C2H5O)3Si(CH2)2Si(OC2H5)3 and octadecyltriethoxysilane C18H37Si(OC2H5)3. The protective ability of the polymer film adsorbed on passivated iron was examined by polarization measurement in oxygenated 0.1 M KClO4 solutions with and without 1 × 10-4 and 1 × 10-3 M of Cl-. The values of the open-circuit potential, Eoc were monitored with the immersion time, t in these solutions. The Eoc value of the passivated electrode in 0.1 M KClO4 was maintained high, more than -0.2 V/SCE in the initial region of t up to 10 h, indicating the presence of a passive film on the electrode. Thereafter, Eoc decreased to -0.4 V/SCE abruptly, exhibiting breakdown of the passive film. The value of the passivated electrode covered with the polymer film remained almost constant around -0.04 V/SCE during immersion for 45 h. The protective efficiency, P (%) of the polymer film on passivated iron was extremely high, more than 99.9% unless the passive film was broken down, indicating complete protection of iron against corrosion. The times for breakdown on the passivated electrode and polymer-coated one diminished with an increase in the concentration of Cl-. The polymer-coated surface was analyzed by electron-probe microanalysis after immersion in 0.1 M KClO4 for 24 h.

Original languageEnglish
Pages (from-to)3542-3548
Number of pages7
JournalCorrosion Science
Volume50
Issue number12
DOIs
Publication statusPublished - 2008 Dec 1

Keywords

  • A. Organic polymer coating
  • A. Passivated iron
  • B. EPMA
  • B. Polarization
  • C. Passive film breakdown

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Materials Science(all)

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