CHEMICAL-COMPOSITION AND SEMICONDUCTING BEHAVIOR OF STAINLESS-STEEL PASSIVE FILMS IN CONTACT WITH ARTIFICIAL SEAWATER

Passive films formed on AISI 316L stainless steer in nitric acid solut ion and placed in contact with artificial seawater were investigated b y Auger and XPS analyses, capacitance measurements and photoelectroche mical measurements. The evolution of the corrosion potential is explai ned based on the electronic behaviour of the inner and outer layers of the film above and below the flatband potential. The correlation betw een the electronic structure of the film and the tendency to localised corrosion is also discussed, suggesting that the film breakdown invol ves the ionization of localized states and/or surface states situated deep in the bandgap. (C) 1998 Elsevier Science Ltd. All rights reserve d.