Published April 15, 2009 | Version v1
Journal article

Study of passive films formed on mild steel in alkaline media by the application of anodic potentials

  • 1. Universidade de Vigo, E.T.S.E.I., Campus Universitario, 36310 Vigo (Spain)
  • 2. ICEMS - Instituto Superior Tecnico, Universidade Tecnica de Lisboa, Av. Rovisco Pais, 1049 - 001 Lisboa (Portugal)
  • 3. EST Setubal, DEM, Instituto Politecnico de Setubal, Campus IPS, 2910 Setubal (Portugal)

Description

In this paper, iron oxide thin layers formed on mild steel substrates in alkaline media by the application of different anodic potentials were studied in order to characterize their morphology, composition and electrochemical behaviour, in particular under conditions of cathodic protection. The surface composition was evaluated by X-Ray Photoelectron Spectroscopy (XPS) and Auger Electron Spectroscopy (AES). The morphology of the surface oxides was studied via Atomic Force Microscopy (AFM). The electrochemical behaviour of the surface oxides was studied using Electrochemical Impedance Spectroscopy (EIS). The results showed that the surface film is composed by Fe2+oxides and Fe3+ oxides and/or hydroxides. The contribution of Fe2+ species vanishes when the potential of film formation increases in the passive domain. Two distinct phases were differentiated in the outer layers of the surface film, which proves that film growing is topotactic in nature

Availability note (English)

Available from http://dx.doi.org/10.1016/j.matchemphys.2008.11.012

Additional details

Identifiers

DOI
10.1016/j.matchemphys.2008.11.012;
PII
S0254-0584(08)00898-5;

Publishing Information

Journal Title
Materials Chemistry and Physics
Journal Volume
114
Journal Issue
2-3
Journal Page Range
p. 962-972
ISSN
0254-0584
CODEN
MCHPDR

Optional Information

Copyright
Copyright (c) 2008 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.