Advances in Mg-Al-layered double hydroxide steam coatings on Mg alloys: A review

Layered double hydroxide (LDH) coatings on magnesium (Mg) alloys shine brightly in the field of corrosion protection because of their special ion-exchange function. State-of-the-art steam coating as a type of LDH film preparation technique has emerged in recent years because only pure water is required as the steam source and its environmentally friendly LDH coating fits the current need for green development. Moreover, this coating can effectively inhibit the corrosion of the Mg alloy substrate due to the chemical bonding between the coating and the Mg alloy substrate. This review systematically explains cutting-edge advancements in the growth mechanism and corrosion behavior of LDH steam coatings, and analyzes the advantages and limitations of the steam-coating method. The influencing factors including pressure, CO2 /CO3 2 -, aluminum content of the substrate alloy, solution type, and acid-pickling pretreatment, as well as the post-treatment of steam-coating defects, are comprehensively elucidated, providing new insights into the development of the in situ steam-coating technique. Finally, existing issues and future prospects are discussed to further accelerate the widespread application of Mg alloys.& COPY; 2023 Chongqing University. Publishing services provided by Elsevier B.V. on behalf of KeAi Communications Co. Ltd.This is an open access article under the CC BY-NC-ND license ( http://creativecommons.org/licenses/by-nc-nd/4.0/ )Peer review under responsibility of Chongqing University

Automated summary

The LDH steam coating technique can effectively inhibit the corrosion of magnesium alloys by providing a coating with ion-exchange function. It is environmentally friendly and cost-effective, and provides precise control over film thickness. This review provides comprehensive insights into the growth mechanism and corrosion behavior of LDH steam coatings, and explores the influencing factors, offering new perspectives for the development of this technique.