Article ID Journal Published Year Pages File Type
1470351 Corrosion Science 2011 13 Pages PDF
Abstract

The corrosion mechanisms of Al–Cr–Fe and Al–Cu–Fe–Cr complex metallic alloys have been investigated by potentiodynamic and potentiostatic polarization. Very good passivation of the Al–Cr–Fe surface is exhibited from 1 M H2SO4 to 1 M NaOH solutions, which was confirmed by ICP-OES analysis over a period of 273 days. Potentiostatically formed passive films analysed by XPS revealed chromium enrichment in the outermost layer of the aluminium oxy-hydroxide film. Although Al–Cu–Fe–Cr showed passivation during potentiodynamic polarization, heavy active corrosion at OCP was revealed by ICP-OES. For the Al–Cu–Fe–Cr alloy, the 10% content of Cr is insufficient to maintain a protective “chemically stable” Cr oxide/hydroxide.

Research highlights► Al–Cr–Fe and Al–Cu–Fe–Cr complex metallic alloys are passive in pH 0 and 14 upon polarization. ► High “chemical” stability of passive over long exposure to 1 M H2SO4 and 1 M NaOH only found for Al–Cr–Fe alloy. ► Chromium cations enrichment is found in the outermost part of passive film on Al–Cr–Fe. ► Very thin mixed Al–Cr oxy-hydroxide is sufficient to efficiently stabilize the passive film/solution interface.

Related Topics
Physical Sciences and Engineering Materials Science Ceramics and Composites
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