Self-repairing functionality and corrosion resistance of in-situ Mg-Al LDH film on Al-alloyed AZ31 surface

A novel Mg-Al LDH film was in-situ prepared hydrothermally in an alkaline aqueous solution on an Al-alloyed AZ31 substrate. The structural, chemical and functional characteristics of the film were explored by means of scanning electron microscope (SEM), X-ray diffraction (XRD), energy dispersive spe...

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Bibliographic Details
Published inJournal of magnesium and alloys Vol. 11; no. 5; pp. 1567 - 1579
Main Authors Zhu, Yi-Xing, Song, Guang-Ling, Wu, Peng-Peng
Format Journal Article
LanguageEnglish
Published Elsevier B.V 01.05.2023
KeAi Communications Co., Ltd
Subjects
Corrosion resistance
LDH film
Self-repairing
Surface alloying
Corrosion resistance
LDH film
Surface alloying
Self-repairing
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Summary:A novel Mg-Al LDH film was in-situ prepared hydrothermally in an alkaline aqueous solution on an Al-alloyed AZ31 substrate. The structural, chemical and functional characteristics of the film were explored by means of scanning electron microscope (SEM), X-ray diffraction (XRD), energy dispersive spectrometer (EDS), polarization curve, AC impedance and salt immersion tests, respectively. The anti-corrosion results indicated that the Mg-Al LDH film on the Al-alloyed AZ31 surface could effectively protect the AZ31 from corrosion attack even after 90 days of immersion in 3.5 wt.% NaCl solution. The protection performance is surprisingly better than most of the reported coatings on Mg alloys. More interestingly, when the Mg-Al LDH film was scratched, the exposed Al-alloyed surface might gradually release metal ions and re-generate dense LDH nano-sheets in the corrosive environment to inhibit the further corrosion there, exhibiting a self-repairing behavior. The combination of the benign long-term protection and desirable self-repairing performance in this new process of surface-alloying and LDH-formation may significantly extend the practical application of magnesium alloys.
ISSN:2213-9567
2213-9567
DOI:10.1016/j.jma.2021.11.019