Semiconducting properties of passive films formed on stainless steels: Influence of the alloying elements

Journal Article · Sun Nov 01 04:00:00 EST 1998 · Journal of the Electrochemical Society

DOI:https://doi.org/10.1149/1.1838880· OSTI ID:289411

Hakiki, N E; Belo, M D.C. ^[1]; Simoes, A M.P.; Ferreira, M G.S. ^[2]

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1. CNRS, Vitry-sur-Seine (France). Centre d`Etudes de Chimie Metallurgique
2. Inst. Superior Tecnico, Lisboa (Portugal). Dept. de Engenharia Quimica

Passive films formed on stainless steels in a borate buffer solution (pH 9.2) have been investigated by capacitance measurements and photoelectrochemistry. The study was carried out on films formed on AISI type 304 and 316 stainless steels and high purity alloys with differing chromium, nickel, and molybdenum contents. Complementary research by Auger analysis shows that the passive films are composed essentially of an inner chromium region in contact with the metallic substrate and an outer iron oxide region developed at the film/electrolyte interface. The semiconducting properties of the passive films are determined by those of the constituent chromium and iron oxides which are of p-type and n-type, respectively. Thus the influence of the alloying elements on the semiconducting properties of the passive films is explained by changes in the electronic structure of each of these two oxide regions.

• Sponsoring Organization: USDOE
• OSTI ID: 289411
• Journal Information: Journal of the Electrochemical Society, Journal Name: Journal of the Electrochemical Society Journal Issue: 11 Vol. 145; ISSN 0013-4651; ISSN JESOAN
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CHROMIUM OXIDES
ELECTRICAL PROPERTIES
ELECTRONIC STRUCTURE
IRON OXIDES
PASSIVATION
PROTECTIVE COATINGS
STAINLESS STEEL-304
STAINLESS STEEL-316