Protective chromate-free conversion coatings on AMg6 aluminum alloy with different types of surface treatment

• Ya.A. Kuzenkov, D.O. Chugunov, S.V. Oleynik and V.L. Voititsky

A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Leninsky pr. 31, 119071 Moscow, Russian Federation

Abstract: Al-Mg alloys with a high Mg content (above 4.5%) are more sensitive to corrosion than alloys with a low Mg content. Pretreatment of the alloy also affects its sensitivity to corrosion. Previously, it was shown that the alkaline chromate-free converting composition IFKhANAL-3 makes it possible to obtain conversion coatings with high protective properties, regardless of the heat treatment. In the current work, the protective properties of IFKhANAL-3 conversion coatings on AMg6 aluminum alloy were studied for annealed samples and for samples after rolling. It was shown that an increase in the temperature of the converting composition and addition of corrosion inhibitors to the composition reduces the amount of Si-containing oxides in the conversion coating and removes the difference in the protective properties of coatings obtained on annealed samples and on samples after rolling.

Keywords: aluminum alloys, conversion coatings, pitting corrosion, corrosion inhibitors

Int. J. Corros. Scale Inhib., 2022, 11, no. 2, 541-552
doi: 10.17675/2305-6894-2022-11-2-5

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