Alloy Corrosion-Fundamental Studies of Dissolution and Passivity of Alloys and Compounds.

摘要

The effects of Si additions to Fe on the stability of the passive film have been investigated over the pH range from 0 to 10. Silicon, in concentrations below 14.5% decreased the stability of the film. In sulfate solutions the passive current density was up to an order of magnitude less for the Fe-14.5 Si alloy relative to the Fe-8 Si alloy; the active peak decreased three orders of magnitude. In 0.1 N HCl, Fe-14.5 Si had a passive region. There was no passive zone for Fe, Fe-3 Si, or Fe-8 Si alloys in this solution. Surface analysis techniques indicate that the abrupt change in stability with the addition of 14.5% Si is not the result of an SiO2 film on the surface. (Author)