Improvement of healing treatment with NaNO3 for a passivated iron electrode covered with an ultrathin polymer coating to prevent iron corrosion in some solutions containing aggressive anions

Kunitsugu Aramaki, Tadashi Shimura

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

An ultrathin and ordered polymer coating was prepared on a passivated iron electrode by modification of a 16-hydroxyhexadecanoate ion HO(CH2)15CO2- self-assembled monolayer with 1,2-bis(triethoxysilyl)ethane (C2H5O)3Si(CH2)2Si(OC2H5)3 and octyltriethoxysilane C8H17Si(OC2H5)3. Further, the passivated and polymer-coated electrode was healed by treatment in 1.0M NaNO3 for 4h. Prevention of passive film breakdown and iron corrosion for the passivated, polymer-coated and healed electrode was examined by monitoring of the open-circuit potential and repeated polarization measurements in oxygenated 0.1M KClO4, 0.1M Na2SO4 and 0.1M NaCl for many hours. The values of the time for passive film breakdown, tbd were >240, 22.2 and 9.5h in these solutions, respectively. The protective efficiencies for the electrode were extremely high, more than 99.9% before tbd, indicating complete protection of substrate iron against corrosion in these solutions, unless passive film breakdown occurred. The presence of NO3- on the passive surface by treatment in 1.0M NaNO3 was detected by X-ray photoelectron and FTIR reflection spectroscopies. The self-healing activity of adsorbed NO3- to suppress passive film breakdown was discussed.

Original languageEnglish
Pages (from-to)4152-4158
Number of pages7
JournalCorrosion Science
Volume53
Issue number12
DOIs
Publication statusPublished - 2011 Dec 1

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Keywords

  • A. Iron
  • B. Polarization
  • C. Neutral inhibition
  • C. Passive films
  • C. Polymer coatings

ASJC Scopus subject areas

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

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