Inhibition of aluminium corrosion in chloride media: an impedance study

Inhibition of the corrosion of pure Al by nitrite and chromate anions in near neutral aqueous chloride solution has been studied by electrochemical impedance spectroscopy, keeping the ionic strength constant by addition of potassium sulphate electrolyte. At negative of the chloride pitting potential...

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Bibliographic Details
Published in:Journal of applied electrochemistry 1994-11, Vol.24 (11), p.1158-1163
Main Authors: Brett, C.M.A., Gomes, I.A.R., Martins, J.P.S.
Format: Article
Language:English
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Summary:Inhibition of the corrosion of pure Al by nitrite and chromate anions in near neutral aqueous chloride solution has been studied by electrochemical impedance spectroscopy, keeping the ionic strength constant by addition of potassium sulphate electrolyte. At negative of the chloride pitting potential impedance spectra show that both anions are successful in reducing corrosion through adsorption, nitride more than chromate. At more positive potentials, nitrate becomes ineffective, whereas chromate remains adsorbed and continues to prevent pitting corrosion, probably through its ability to repair defects in the oxide film. Impedance techniques successfully show the qualitative and quantitative differences between the two inhibitors.
ISSN:0021-891X
1572-8838
DOI:10.1007/BF00241315