In situ structural analysis of corrosion products formed on the surfaces of iron‐based alloys

In situ X‐ray diffraction measurements were performed for analyzing the constituent species of corrosion products freshly formed on the surfaces of pure iron and iron‐based alloys, namely, iron − 0.58 mass% phosphorus and iron − 3.2 mass% molybdenum. As these elements are often added into corrosion‐resistant steels, their influence on the constituent species of the corrosion products was studied. The sample surfaces were corroded by dropping an NaCl aqueous solution and cyclically exposing them to wet and dry atmospheres. The results revealed that γ‐FeOOH was formed as the main corrosion product on the surface of the iron‐based alloys, and small amounts of species such as green rust (GR), and magnetite were formed depending on the addition of the alloying elements. It is considered that the formation of different constituent species of the corrosion products is influenced by the alloying elements in the corrosion products. It was shown that in situ X‐ray diffraction measurements enable us to obtain information on different species in the corrosion products formed under various conditions. Copyright © 2008 John Wiley & Sons, Ltd.

[1]  Y. Waseda,et al.  Analysis of Iron Oxyhydroxides and Oxides Converted from Green Rust in Aqueous Solution , 2007 .

[2]  Y. Waseda,et al.  Ex-situ and in-situ X-ray diffractions of corrosion products freshly formed on the surface of an iron–silicon alloy , 2007 .

[3]  Y. Waseda,et al.  Atomic-scale structure of ferric oxyhydroxide formed from Fe-Si alloy in aqueous solutions containing different salts , 2006 .

[4]  Shigeru Suzuki,et al.  In-situ X-ray Diffraction of Corrosion Products Formed on Iron Surfaces , 2005 .

[5]  K. Asami,et al.  In-depth distribution of rusts on a plain carbon steel and weathering steels exposed to coastal-industrial atmosphere for 17 years , 2003 .

[6]  S. Nasu,et al.  Corrosion behavior of steel under wet and dry cycles containing Cr3+ ion , 2003 .

[7]  Yoshio Kobayashi,et al.  Mössbauer Studies on Particle Volume Distribution of α-FeOOH in Rust Formed on Weathering Steel , 2000 .

[8]  M. Abdelmoula,et al.  Mechanisms of formation and structure of green rust one in aqueous corrosion of iron in the presence of chloride ions , 1998 .

[9]  P. Refait,et al.  On the stoichiometry and pourbaix diagram of Fe(II)-Fe(III) hydroxy-sulphate or sulphate-containing green rust 2: An electrochemical and Mössbauer spectroscopy study , 1996 .

[10]  Martin Stratmann,et al.  The mechanism of the oxygen reduction on rust-covered metal substrates , 1994 .

[11]  Martin Stratmann,et al.  In situ Möβbauer spectroscopic study of reactions within rust layers , 1989 .

[12]  U. R. Evans,et al.  MECHANISM OF ATMOSPHERIC RUSTING , 1972 .