SEDL / STP / STP596-EB / STP39059S

Composition of Protective Films Formed on Iron and Stainless Steels

Lumsden, JB
Adjunct assistant professor and professor, The Ohio State University, Columbus, Ohio

Staehle, RW
Adjunct assistant professor and professor, The Ohio State University, Columbus, Ohio

Pages: 13    Published: Jan 1976

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Abstract

The composition of passive films formed on austenitic stainless steels have been determined using Auger electron spectroscopy. The films were found to be enriched in chromium which is consistent with the understanding of the relative insolubility of chromium compared to that of iron and nickel. However, the films were depleted in both silicon and molybdenum which are thermodynamically more stable than chromium in the solutions used. Thus, it is not possible to rationalize the improved resistance to acid solutions and solutions containing chlorides obtained by the addition of silicon and molybdenum to stainless steels using a selective-dissolution-enrichment model.