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Evolution of the impedance diagrams of 8090 Alloy in saline solution with low aggressiveness
Author(s) -
Conde A.,
de Damborenea J. J.
Publication year - 1999
Publication title -
materials and corrosion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.487
H-Index - 55
eISSN - 1521-4176
pISSN - 0947-5117
DOI - 10.1002/(sici)1521-4176(199908)50:8<447::aid-maco447>3.0.co;2-h
Subject(s) - corrosion , aluminium , dielectric spectroscopy , alloy , intergranular corrosion , metallurgy , materials science , aluminium alloy , electrolyte , electrochemistry , chemistry , electrode
Aircraft industry has focused in the search for new materials with high performance properties such as composite materials and aluminium alloys. During the last decade a new generation of aluminium‐lithium alloys have been developed due to their low density and high elastic modulus. From corrosion viewpoint most of the work published on these alloys are based on atmospheric exposure tests and accelerated laboratory tests. Recently, an increasing interest has been paid in the use of electrochemical techniques on aluminium alloys due to their main advantages: determining of corrosion kinetics in real time and knowledge of the corrosion mechanism. This paper attempts to establish a correlation between the evolution of the impedance diagrams and the process of the attack undergone by a commercial 8090 T8171 alloy in sodium chloride solutions. During the first 100 h of immersion the electrochemical impedance spectroscopy reveals that the corrosion process is under charge transfer resistance control. After this time, the technique showed clearly the role of the adsorbed ions from the electrolyte, which promotes an intergranular attack on the alloy.