The Impedance characteristics of passive films on iron have been investigated focused on the electrical potential profile in the film. Electrochemical redox reactions on the passive films were not affected by the film thickness even when increased to several ten times larger than the usual passive films. At several stages of the cathodic reduction of the films, a contact resistance of mercury through the film was measured and it was found that the resistivity of the film caused at the outermost part of the passive layer. It was concluded that the highest electrical fields in the passive films existed in this part, and that this part has different properties from the rest of the film.
ASJC Scopus subject areas
- 化学 (全般)