The study of protective film formation on Mg alloys by exposure to sodium selenite solutions was conducted. Anodic polarization studies, electrochemical impedance spectroscopy studies, morphological analysis, and Energy-dispersive X-ray spectroscopy were performed on AZ31 Mg alloy after coating treatment in different concentrations of sodium selenite. The corrosion resistance was improved by around 5 times compared with control. Improved resistance to localized corrosion was observed in the coatings treated by 5 mM or 10 mM sodium selenite. The protection mechanism was ascribed to the transformation of selenite to insoluble selenium, the formation of insoluble MgSeO3 hydrate, and polymerization of amorphous selenium.

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Published in Materials, v. 14, issue 2, 286.

© 2021 by the authors. Licensee MDPI, Basel, Switzerland.

This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).

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This research was funded by The Army Research Laboratory grant number W911NF-14-2- 0004.

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The following are available online at https://www.mdpi.com/1996-194 4/14/2/286/s1, Figure S1: Bode plot for control, Figure S2: Bode Plot for 1 mM Selenite, Figure S3: Bode Plot for 5 mM Selenite, Figure S4: Bode Plot for 10 mM Selenite.

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