Investigation of the electrochemical corrosion behavior and passive film for Fe-Mn, Fe-Mn-Al, and Fe-Mn-Al-Cr alloys in aqueous solutions

Journal Article · Thu Jan 01 04:00:00 EST 1998 · Corrosion

DOI:https://doi.org/10.5006/1.3284826· OSTI ID:644332

Zhu, X M; Zhang, Y S ^[1]

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1. Dalian Railway Inst. (China). Dept. of Materials Science and Engineering

The corrosion behavior of austenitic Fe-(17 wt% to 31 wt%) Mn-(1 wt% to 9 wt%) Al-(1 wt% to 7 wt%) Cr alloys in different aqueous solutions and the corrosion protection mechanism induced by adding Al or Al and Cr, were studied by anodic polarization and Auger electron spectroscopic/x-ray photoelectron spectroscopic (AES/XPS) analysis. Binary Fe-(17 wt% to 31 wt%) Mn-0.15 wt% C alloys passivated with difficulty in 1 mol/L sodium sulfate (Na{sub 2}So{sub 4}) solution. Mn was greatly detrimental to the corrosion resistance of mild steel. Corrosion current density (I{sub corr}) decreased, and the corrosion potential (E{sub corr}) increased with increasing Al or Cr content in the Fe-Mn-based alloys. Polarization curves exhibited a stable passive region for Al or Cr concentrations >{approximately}5 wt%. Appropriate combinations of Al and Cr added to Fe-Mn alloys obviously promoted electrochemical corrosion resistance of the alloys. The passive film formed on the Fe-24% Mn-4% Al-5% Cr alloy in Na{sub 2}So{sub 4} solution consisted of three parts: bound water and hydroxides probably were present at the surface; the outer portion of film was made up of a mixture of Fe, Mn, Cr, and Al oxides; and a transition region existed, consisting of low valence oxides and metallic Fe, Mn, Cr, and Al between the passive film and the matrix. The corrosion resistance probably was imparted by a barrier film of bound water, hydroxide, and oxides of Cr, Al, and Fe.

• Sponsoring Organization: USDOE
• OSTI ID: 644332
• Journal Information: Corrosion, Journal Name: Corrosion Journal Issue: 1 Vol. 54; ISSN 0010-9312; ISSN CORRAK
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM ALLOYS
AQUEOUS SOLUTIONS
CHROMIUM ALLOYS
ELECTROCHEMICAL CORROSION
FILMS
IRON ALLOYS
MANGANESE ALLOYS
PASSIVATION
SPECTROSCOPY