Title

LOCALIZED CORROSION OF 7XXX-T7 ALUMINUM ALLOYS IN CHLORIDE MEDIA

LOCALIZED CORROSION OF 7XXX-T7 ALUMINUM ALLOYS IN CHLORIDE MEDIA

Authorship

SILVA, JOSÉ WILSON DE JESUS; PEREIRA, MARINALDA CLAUDETE; DUTRA, CONCEIÇÃO APARECIDA MATSUMOTO; NAKAZATO, ROBERTO ZENHEI; CODARO, EDUARDO NORBERTO

SILVA, JOSÉ WILSON DE JESUS

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PEREIRA, MARINALDA CLAUDETE

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DUTRA, CONCEIÇÃO APARECIDA MATSUMOTO

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NAKAZATO, ROBERTO ZENHEI

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CODARO, EDUARDO NORBERTO

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DOI

10.5151/2594-5327-3973

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Abstract

Corrosion behavior of 7010-T7, 7050-T7 and 7475-T7 aluminum-zinc alloys in weakly acidic 5% NaCl solution has been investigated using d.c. and a.c. electrochemical techniques. Dissolved oxygen influence upon corrosion mechanism has been discussed. Corrosion rate of these alloys in aerated solution is controlled by oxygen diffusion from solution towards cathodic sites through pores in corrosion films. Whereas in de-aerated solution, corrosion rate is mainly controlled by the dissolution process of a thin passive film. Pitting corrosion susceptibility increases in this order: 7475-T7 < 7010-T7 < 7050-T7 in both aerated and de-aerated environments.

Corrosion behavior of 7010-T7, 7050-T7 and 7475-T7 aluminum-zinc alloys in weakly acidic 5% NaCl solution has been investigated using d.c. and a.c. electrochemical techniques. Dissolved oxygen influence upon corrosion mechanism has been discussed. Corrosion rate of these alloys in aerated solution is controlled by oxygen diffusion from solution towards cathodic sites through pores in corrosion films. Whereas in de-aerated solution, corrosion rate is mainly controlled by the dissolution process of a thin passive film. Pitting corrosion susceptibility increases in this order: 7475-T7 < 7010-T7 < 7050-T7 in both aerated and de-aerated environments.

Keywords

aluminum alloys, eis, pitting corrosion.

aluminum alloys, eis, pitting corrosion.