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In Situ X-Ray-Diffraction Studies of Passive Oxide Films

Published online by Cambridge University Press:  29 November 2013

Mary P. Ryan ,
Michael F. Toney ,
Alison J. Davenport  and
Lucy J. Oblonsky
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Extract

Most metals are thermodynamically unstable in aqueous environments. They are kinetically stabilized by the formation of very thin “passive” oxide films that provide protection from corrosion. The technological importance of passive films has led to widespread investigation of their structure and chemistry. However, despite decades of work since Michael Faraday first described the existence of the passive film on iron, the atomic structure of these films is still poorly understood. This is because the films are so thin (typically only a few nanometers thick), making measurements difficult, and because the structure can only be investigated in the (wet) electrochemical environment in which these films form.

The electrochemical nature of the formation of these oxide films is shown in Figure 1, which presents the current response of an iron electrode in an aqueous solution to an applied voltage (potential). As the potential is slowly increased from negative (cathodic) to positive (anodic), the iron first begins to dissolve. This area of dissolution is known as the active region, indicating that the iron is corroding freely as ferrous ions (Fe2+). Then, at a sufficiently anodic (oxidizing) voltage, a thin (30 Å) oxide film forms at the iron surface, preventing further dissolution. This results in a marked decrease in the measured current, a phenomenon known as passivity. Over the passive region, the current is virtually independent of applied voltage and remains extremely low, indicating that the iron is protected from additional oxidation or corrosion.

Type
Corrosion Science
Information
MRS Bulletin , Volume 24 , Issue 7 , July 1999 , pp. 29 - 35
Copyright
Copyright © Materials Research Society 1999

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References

1.Uhlig, H.H., in Passivity of Metals, edited by Frankenthal, R.P. and Kruger, J. (The Electrochemical Society, Princeton, NJ, 1978) p. 1.Google Scholar
2.Nagayama, M. and Cohen, M., J. Electrochem. Soc. 109 (1962) p. 781.CrossRefGoogle Scholar
3.Foley, C.L., Kruger, J., and Bechtoldt, C.J., J. Electrochem. Soc. 114 (1967) p. 994.CrossRefGoogle Scholar
4.Kuroda, K., Cahan, B.D., Nazri, Gh., Yeager, E., and Mitchell, T.E., J. Electrochem. Soc. 129 (1982) p. 2163.CrossRefGoogle Scholar
5.O'Grady, W.E., J. Electrochem. Soc. 127 (1980) p. 555.CrossRefGoogle Scholar
6.Eldridge, J. and Hoffman, R.W., J. Electrochem. Soc. 135 (1989) p. 955.CrossRefGoogle Scholar
7.Kerkar, M., Robinson, J., and Forty, A.J., Faraday Discuss. Chem. Soc. 89 (1990) p. 31.CrossRefGoogle Scholar
8.Long, G.G., Kruger, J., Black, D.R., and Kuriyama, M., J. Electroanal. Chem. 150 (1983) p. 603.CrossRefGoogle Scholar
9.Hoffman, R.W., in Passivity of Metals and Semiconductors, edited by Froment, M. (Elsevier Science Publishers, Amsterdam, 1983) p. 147.CrossRefGoogle Scholar
10.Rubim, J.C. and Dünnwald, J., J. Electroanal. Chem. 258 (1989) p. 327.CrossRefGoogle Scholar
11.Gui, J. and Devine, T.M., Corros. Sci. 32 (1991) p. 1105.CrossRefGoogle Scholar
12.Davenport, A.J. and Sansone, M., J. Electrochem. Soc. 142 (1995) p. 7254.Google Scholar
13.Ryan, M.P., Newman, R.C., and Thompson, G.E., J. Electrochem. Soc. 142 (1995) p. L177.CrossRefGoogle Scholar
14.Toney, M.F., Davenport, A.J., Oblonsky, L.J., Ryan, M.P., and Vitus, C.M., Phys. Rev. Lett. 79 (1997) p. 4282.CrossRefGoogle Scholar
15.Wyckoff, R.W., Crystal Structures, vol. 3 (Interscience Publishers, New York, 1965).Google Scholar
16.Dieckmann, R., Solid State Ionics 12 (1984) p.1.CrossRefGoogle Scholar
17.Oblonsky, L.J., Davenport, A.J., Ryan, M.P., Isaacs, H.S., and Newman, R.C., J. Electrochem. Soc. 144 (1997) p. 2398.CrossRefGoogle Scholar
18.Büchler, M., Schmuki, P., Böhni, H., Stenberg, T., and Mantyla, T., Electrochem. Soc. Proc. 96-18 (The Electrochemical Society, Pennington, NJ, 1996) p. 172.Google Scholar
19.Sewell, P.B., Stockbridge, C.D., and Cohen, M., J. Electrochem. Soc. 108 (1961) p. 933.CrossRefGoogle Scholar
20.Warren, B.E., X-ray Diffraction (Addison-Wesley, New York, 1969) p. 275, p. 227.Google Scholar
21.Sebastian, M.T. and Krishna, P., Random, Non-Random and Periodic Faulting in Crystals (Gordon & Breach Science Publishers, Amsterdam, 1994).Google Scholar
22.Sato, N. and Kudo, K., Electrochim. Acta 16 (1971) p. 447.CrossRefGoogle Scholar
23.Huang, Z.Q. and Ord, J.L., J. Electrochem. Soc. 132 (1985) p. 24.CrossRefGoogle Scholar
24.Zakroczymski, T. and Szklarska-Smialowska, Z., J. Electrochem. Soc. 132 (1985) p. 2548.CrossRefGoogle Scholar
25.Schmuki, P., Virtanen, S., Davenport, A.J., and Vitus, C.M., J. Electrochem. Soc. 143 (1996) p. 574.CrossRefGoogle Scholar
26.Hoar, T.P., J. Electrochem. Soc. 117 (1970) p. 17.Google Scholar
27.McBee, C.L. and Kruger, J., Electrochim. Acta 17 (1972) p. 1337.CrossRefGoogle Scholar
28.Ryan, M.P., Newman, R.C., and Thompson, G.E., Philos. Mag. B 70 (1994) p. 241.CrossRefGoogle Scholar
29.Oblonsky, L.J., Ryan, M.P., and Isaacs, H.S., J. Electrochem. Soc. 145 (1998) p. 1922.CrossRefGoogle Scholar
30.Wagner, C., Ber. Bunsen-Ges. 77 (1973) p. 1090.CrossRefGoogle Scholar
31.Siegel, R.W., Nanostruc. Mater. 3 (1993) p. 1.CrossRefGoogle Scholar