Abstract

The film thickness, the immersion potential, and the hydrogen evolution reaction on the passivated Fe-Ni alloys were investigated in a borate buffer solution at pH 8.39. The results are discussed in connection with a previous paper in which the composition and structure of passive films were studied by means of coulometry and colorimetric analysis. The following conclusions are obtained:(1) The exchange current density and the Tafel slope of the hydrogen evolution reaction on the passivated Fe-Ni alloys decrease with increasing Ni content and show abrupt changes at 30 wt%Ni. This is probably due to Ni3O4 which remains unreduced on the surface during the cathodic process. (2) The immersion potential of the passivated Fe-Ni alloys is likely to be related with the activity of γ-Fe2O3 in the outer layer of passive films. (3) There is a hyperbolic relation between film thickness and Ni content in the alloys. This can be explained by assuming that the passive films consist of a fine mixture of Ni and Fe oxides. (4) The corrosion resistivity of the alloys is related with the excess oxygen concentration in the outer layer of the passive films.

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.