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Effect of aluminate ion loading on the corrosion behavior of layered double hydroxide (LDH) coating of Mg-3Al-1Zn (AZ31) alloy was investigated. The corrosion inhibition performance of NaAlO2 for AZ31 was examined by immersion and polarization tests. Then, aluminate ion-loaded LDH (LDHAlO2) was synthesized from hydrotalcite (LDHCO3) and co-deposited with magnesium and aluminum double hydroxide on AZ31 by electrophoretic co-deposition. Polarization, electrochemical impedance (EI) and wet-dry cyclic corrosion tests were conducted on the LDHAlO2- and LDHCO3-coated specimens. Adding 10-50 mmol/L NaAlO2 to 0.1 mol/L NaCl solution induced a clear passive region on the polarization curves of AZ31 and shifted the breakdown potential over -1.0 V (Ag/AgCl), indicating the corrosion inhibition property of NaAlO2. In the polarization and EI tests, the aluminate ion loading did not noticeably enhance the corrosion protection ability of the LDH coating as shown by higher quasi-passive current density and lower Rp than without loading. However, in the wet-dry corrosion tests, the LDHAlO2-coated AZ31 demonstrated less weight gain and fewer clusters of shallow micro-pits, while the LDHCO3-coated AZ31 showed numerous deeper pits on the entire surface. It was revealed that loading aluminate ions to the LDH coatings is promising for enhancing their corrosion protection ability in atmospheric environments.

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• Creative Commons BY-NC-ND Attribution-NonCommercial-NoDerivs 4.0 International
  

  This is an author-created, un-copyedited version of an article accepted for publication/published in Journal of The Electrochemical Society. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at https://doi.org/10.1149/1945-7111/ad13db.

Keyword: magnesium alloy, layered double hydroxide coating, corrosion inhibitor, electrophoretic co-deposition, atmospheric corrosion environment

Date published: 2023-12-01

Publisher: The Electrochemical Society

Journal:

• JOURNAL OF THE ELECTROCHEMICAL SOCIETY (ISSN: 00134651) vol. 170 p. 121502-121502

Funding:

Manuscript type: Author's version (Accepted manuscript)

MDR DOI: https://doi.org/10.48505/nims.4337

First published URL: https://doi.org/10.1149/1945-7111/ad13db

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Updated at: 2024-12-20 16:30:55 +0900

Published on MDR: 2024-12-20 16:30:55 +0900