LDH conversion films for active protection of AZ31 Mg alloy

Journal article (2023)

Authors

B. Pillado Universidad Complutense de Madrid
B. Mingo The University of Manchester
R. del Olmo Military University of Technology, Universidad Complutense de Madrid
E. Matykina Universidad Complutense de Madrid
A.M. Kooijman Team Arjan Mol - Mechanical, Maritime and Materials Engineering
Y. Gonzalez Garcia Team Yaiza Gonzalez Garcia - Mechanical, Maritime and Materials Engineering
R. Arrabal Universidad Complutense de Madrid
M. Mohedano Universidad Complutense de Madrid
Research Group
Team Arjan Mol (Mechanical, Maritime and Materials Engineering) (TU Delft)
Copyright: © 2023 B. Pillado, B. Mingo, R. del Olmo, E. Matykina, A.M. Kooijman, Y. Gonzalez Garcia, R. Arrabal, M. Mohedano
DOI: https://doi.org/10.1016/j.jma.2022.09.014
More Info
expand_more

Published Date

2023

Language

English

Faculty

Mechanical, Maritime and Materials Engineering

Department

Materials Science and Engineering

Research Group

Team Arjan Mol

Abstract

Zinc aluminium (Zn-Al) and lithium aluminium (Li-Al) – layered double hydroxides (LDH) coatings with incorporated inhibitors (Li−, Mo− and W−based) were successfully synthesized on AZ31 Mg alloy. Zn−Al LDH W and Li−Al LDH Li showed the highest corrosion resistance and were selected for further evaluation. SEM cross−section examination revealed a bi−layer structure composed of an outer part with loose flakes and a denser inner layer. XRD, FTIR, and XPS analysis confirmed the incorporation of the inhibitors. Post−treatments with corrosion inhibitors containing solutions resulted in the selective dissolution of the most external layer of the LDH coating, reducing the surface roughness, hydrophilicity and paint adhesion of the layers. Active corrosion properties were confirmed by SVET evaluation for the Zn−Al LDH W coating. The proposed active corrosion mechanism involves the ion−exchange of aggressive Cl− ions, deposition of hydroxides and competitive adsorption of W−rich corrosion inhibitors.