Effect of Al Content in the Mg-Based Alloys on the Composition and Corrosion Resistance of Composite Hydroxide Films Formed by Steam Coating

Ishizaki, Takahiro; Miyashita, Tomohiro; Inamura, Momo; Nagashima, Yoshiki; Serizawa, Akimi

doi:10.3390/ma12071188

Cited by 14 publications

(4 citation statements)

References 38 publications

(40 reference statements)

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“…In the case of PEO-DS sample, second LDH peak (006 reflection) at 23.3° is clearly visible and the relative intensity of both LDH peaks ((003) and (006) reflections) against spinel PEO peak increases as compared to PEO-D sample. These peaks are related to hydroxide-loaded LDH, which is quite typical for LDH grown on various magnesium alloys 45,63,64 . The broad peak around 14° at PEO and PEO-S patterns corresponds to thin nanocrystalline surface film on PEO layer and is not related to LDH phase.…”

Section: Resultsmentioning

confidence: 83%

Use of synergistic mixture of chelating agents for in situ LDH growth on the surface of PEO-treated AZ91

Petrova

Serdechnova

Shulha

et al. 2020

Sci Rep

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through the open PEO pores 30-32. However, the LDH growth on PEO treated magnesium alloys is not so simple due to the complicity of the system, even if noticeable effect for corrosion protection is expected 33,6. Recently, Zeng et al. suggested a two-step synthesis of Zn,Al-LDH coating on anodized AZ31 alloy 34. In that work the preliminary synthesized LDH containers were deposited on the surface of PEO layer by immersion AZ31 sample in the LDH containing solution at autoclave conditions and further covered with poly(lactic acid) coating (PLA). An overall significant improvement of corrosion properties was observed for both LDH and LDH/PLA covered samples in comparison with bare AZ31. Wu et al. proposed direct hydrothermal synthesis of Mg,M-LDH films (M = Al, Cr, Fe) on anodized AZ31 with the oxide layer acting as the source of magnesium 35,36. The same approach was used by Zhang et al. for anodized and PEO-treated AZ31 samples 37-39. In brief, these existing single-step approaches for LDH sealing of oxidized magnesium alloys are performed in autoclaves since they require high pressure conditions and temperatures above 100 °C, which significantly limits the possibility of industrial applications of those methods, e.g. for transport applications. In the cases, when autoclave conditions are not required, LDH formation takes place in carbonated electrolytes 40,41 and CO 2 containing environment due to high sorption ability of LDH towards CO 2 42. These LDH are extremely hard to functionalize due to the high charge density of carbonate species 43,44. Thus, formation of "dead" LDH occurs and corrosion inhibitors cannot be intercalated for further "smart" active protection. Overall, LDH sealing of PEO layers is significantly more problematic in the case of magnesium in comparison with aluminum alloys. Recently, Shulha et al. have demonstrated the possibility of Mg,Al-LDH formation on bare AZ91 magnesium alloy via application of chelating agents 45. Introduction of chelating agents to the reaction system led to the formation of soluble metal complexes and therefore to the increase of concentration of soluble Al(III) and Mg(II) species in the pH range of 9.6-10.3, which is favourable for LDH growth. In this work, sodium salts of salicylic, ethylenediaminetetraacetic and nitrilotriacetic acids were chosen with different complex stability constants with magnesium (log K Mg-L) of 4.7, 8.64 and 10.2, respectively. It was shown, that in the solutions containing chelating agents the concentration of soluble forms of magnesium (as Mg 2+ ions and Mg 2+-ligand complexes) was maintained relatively high in the pH range necessary for LDH formation (ca. 50% of free Mg 2+ in the case of nitrilotriacetic acid (NTA) chelating agent addition). No external source of magnesium ions was added to the electrolyte. Instead, chelating agents assisted the dissolution of the substrate, providing enough soluble magnesium species for LDH formation. This approach allowed the formation of LDH flakes on the surface under relatively mild conditions (95...

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Section: Resultsmentioning

confidence: 83%

Use of synergistic mixture of chelating agents for in situ LDH growth on the surface of PEO-treated AZ91

Petrova

Serdechnova

Shulha

et al. 2020

Sci Rep

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show abstract

“…In the high temperature environment, the reaction between Mg–Li alloy and steam will occur as follows (Equation ), and the main products are Mg(OH) 2 and MgO. [ 31 ] In this process, the insufficient or uneven contact between Mg–Li alloy and steam may cause SC to generate defects such as micropores and cracks. The hydrothermal solution will penetrate from the crack to partially dissolve the substrate and produce a large amount of Mg 2+ .…”

Section: Analysis and Discussionmentioning

confidence: 99%

Comparative Study on Microstructure, Corrosion Morphology, and Friction Wear Properties of Layered Double Hydroxide/Steam Coating Composite Coatings on Mg–Li Alloy

Zhang,

Lian,

Hou

et al. 2024

Adv Eng Mater

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Mg alloy is the preferred material for the lightweight development of manufacturing industry. However, its application is limited due to the poor wear resistance and corrosion resistance. In this experiment, Mg‐Al LDH/SC (Layered double hydroxide/Steam coating) composite coatings were prepared on the surface of LA43M Mg‐Li alloy by steam treatment and in‐situ hydrothermal method for different times (12 h, 18 h, 24 h, 30 h and 36 h). The morphology and structure of the coatings were characterized by SEM, EDS, and XRD, and the friction wear test of the coatings was carried out. The corrosion resistance of the coatings was evaluated by immersion tests and hydrogen evolution experiments. The effect of hydrothermal time on the growth characteristics, wear resistance, and corrosion behavior of LDH/SC coatings in 3.5 wt.% NaCl solution was systematically investigated. In addition, the growth mechanism and corrosion resistance mechanism of the LDH/SC coating were discussed. The results show that the composite coatings is mainly composed of LDH and Mg(OH)2 phases. Appropriately prolonging the hydrothermal reaction time is beneficial to the nucleation and growth of LDH. When the hydrothermal time is 30 h, the prepared coating has the best density, and the prepared coating can significantly improve the corrosion resistance and friction wear properties of the substrate.This article is protected by copyright. All rights reserved.

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“…Therefore, appropriate coating material and methods must be selected to bind the material on alloy matrix. Currently, surface modification of Mg alloys is dominated by physical barrier coatings, such as metal‐based coatings, 92 metal hydroxides and hydrotalcite coatings, 93 metal oxide coatings, 94 silane sol‐gel coatings, 95 polymer coatings, 96 Ca‐P coatings, 97 and others including graphene‐based coatings 98 . In addition, smart self‐healing coatings that are inspired by living organisms, such as chemical conversion coatings, encapsulation coatings, and layer‐by‐layer assembled coatings, attract tremendous attention.…”

Section: Modification Of Magnesium Anodementioning

confidence: 99%

Critical review on development of magnesium alloy as anode inMg‐Airfuel cell and additives in electrolyte

et al. 2021

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Summary This study aimed to provide a critical review of the magnesium‐air fuel cell (MAFC) system to provide readers with an overall comprehension of MAFC, which focuses on the modification of the magnesium anode and properties of saltwater as an electrolyte. Although MAFC is benign to the environment, it is well‐known for its challenging corrosion issue and by‐product deposition that affect its durability for commercialization and long‐term application. Since that MAFC is able to use seawater as electrolyte, it has great potential to be used as an alternative energy option for the marine sector. This journal will dissect the ability of MAFC to be used as a competitive alternative energy. Over the years, researchers have adopted several approaches, such as experimenting with different types of magnesium alloy and anode fabrication techniques, to tackle corrosion problems to alter the microstructure and mechanical properties of the anode in addition to applying a coating protection and using Mg‐based composite material. Furthermore, studies intriguingly and gradually focused on electrolyte formulation with different types of additives to address the debilitating precipitation issue and improve the discharge performance. Given the problems that arise in the system, currently, MAFC commercial products are only suitable as emergency back‐up power. In future work, an improved storage system for MAFC should be built to accommodate the precipitation products while maintaining the desired cell performance.

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Effect of Al Content in the Mg-Based Alloys on the Composition and Corrosion Resistance of Composite Hydroxide Films Formed by Steam Coating

Cited by 14 publications

References 38 publications

Use of synergistic mixture of chelating agents for in situ LDH growth on the surface of PEO-treated AZ91

Use of synergistic mixture of chelating agents for in situ LDH growth on the surface of PEO-treated AZ91

Comparative Study on Microstructure, Corrosion Morphology, and Friction Wear Properties of Layered Double Hydroxide/Steam Coating Composite Coatings on Mg–Li Alloy

Critical review on development of magnesium alloy as anode inMg‐Airfuel cell and additives in electrolyte

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