Anodization of Magnesium Alloys Using Phosphate Solution

Murakami, Koji; Hino, Makoto; Kanadani, Teruto

doi:10.5772/13463

Cited by 4 publications

(3 citation statements)

References 12 publications

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“…This has an application for photoelectrocatalysts due to the stable surface that is generated. There have been several reports by other researchers that focus on the use of phosphate in PEO coatings for Mg and Mg alloys [20][21][22][23][24][25][26][27][28]. The addition of TiO 2 into the electrolyte solution has been noteworthy due to its possible uses with solar energy [29,30], air purification [31,32], photo catalysis [33,34], and corrosion protection [35][36][37].…”

Section: Introductionmentioning

confidence: 99%

TiO₂ Deposition on AZ31 Magnesium Alloy Using Plasma Electrolytic Oxidation

White

Koo

Yun

et al. 2013

Journal of Nanomaterials

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Plasma electrolytic oxidation (PEO) has been used in the past as a useful surface treatment technique to improve the anticorrosion properties of Mg alloys by forming protective layer. Coatings were prepared on AZ31 magnesium alloy in phosphate electrolyte with the addition of TiO2nanoparticles using plasma electrolytic oxidation (PEO). This present work focuses on developing a TiO2functional coating to create a novel electrophotocatalyst while observing the surface morphology, structure, composition, and corrosion resistance of the PEO coating. Microstructural characterization of the coating was investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM) followed by image analysis and energy dispersive spectroscopy (EDX). The corrosion resistance of the PEO treated samples was evaluated with electrochemical impedance spectroscopy (EIS) and DC polarization tests in 3.5 wt.% NaCl. The XRD pattern shows that the components of the oxide film include Mg from the substrate as well as MgO and Mg2TiO4due to the TiO2nanoparticle addition. The results show that the PEO coating with TiO2nanoparticles did improve the corrosion resistance when compared to the AZ31 substrate alloy.

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Section: Introductionmentioning

confidence: 99%

TiO₂ Deposition on AZ31 Magnesium Alloy Using Plasma Electrolytic Oxidation

White

Koo

Yun

et al. 2013

Journal of Nanomaterials

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“… ( a ) X-ray diffraction pattern [ 71 ] and ( b ) backscattered electron cross-sectional micrograph of DOW17 coating on AZ91 alloy [ 72 ], the latter produced by applying constant current with the voltage rising to 200 V. …”

Section: Figurementioning

confidence: 99%

Chromate-Free Corrosion Protection Strategies for Magnesium Alloys—A Review: Part II—PEO and Anodizing

et al. 2022

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Although hexavalent chromium-based protection systems are effective and their long-term performance is well understood, they can no longer be used due to their proven Cr(VI) toxicity and carcinogenic effect. The search for alternative protection technologies for Mg alloys has been going on for at least a couple of decades. However, surface treatment systems with equivalent efficacies to that of Cr(VI)-based ones have only begun to emerge much more recently. It is still proving challenging to find sufficiently protective replacements for Cr(VI) that do not give rise to safety concerns related to corrosion, especially in terms of fulfilling the requirements of the transportation industry. Additionally, in overcoming these obstacles, the advantages of newly introduced technologies have to include not only health safety but also need to be balanced against their added cost, as well as being environmentally friendly and simple to implement and maintain. Anodizing, especially when carried out above the breakdown potential (technology known as Plasma Electrolytic Oxidation (PEO)) is an electrochemical oxidation process which has been recognized as one of the most effective methods to significantly improve the corrosion resistance of Mg and its alloys by forming a protective ceramic-like layer on their surface that isolates the base material from aggressive environmental agents. Part II of this review summarizes developments in and future outlooks for Mg anodizing, including traditional chromium-based processes and newly developed chromium-free alternatives, such as PEO technology and the use of organic electrolytes. This work provides an overview of processing parameters such as electrolyte composition and additives, voltage/current regimes, and post-treatment sealing strategies that influence the corrosion performance of the coatings. This large variability of the fabrication conditions makes it possible to obtain Cr-free products that meet the industrial requirements for performance, as expected from traditional Cr-based technologies.

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“…This electrolyte is notably free of toxic and hazardous compounds commonly used in anodization, e.g. chromates, fluorides [15,16]. The objective of this study was to investigate the surface morphology and composition of Mg substrates after potentiostatic anodization in a 10 M KOH electrolyte for 2 hr at applied potentials representative of the distinct processes (e.g.…”

Section: Introductionmentioning

confidence: 99%

Surface Characterization of Magnesium Anodized in a 10M KOH Electrolyte

Miller

Cipriano

Liu

2014

AMR

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Magnesium (Mg) is a promising implant material for orthopedic applications due to its biodegradability and desirable mechanical properties. However, in order for Mg to have widespread clinical applications, engineering solutions that address the rapid degradation in physiological environments and promote bone-forming activity are needed. The objective of this study was to develop an anodization process using a toxicant-free electrolyte to modulate nanoscale surface features and surface chemistry on Mg. Anodic polarization and potentiostatic anodization tests were used to evaluate the effect of applied potential on surface morphology of Mg in a 10 M KOH electrolyte. Nucleation of oxides as a function of anodization duration was also investigated in order to optimize the synthesis process. The alkaline electrolyte used for anodization of Mg offers an alternative to commercial processes that use hazardous elements. The anodized samples were annealed to investigate the effect of thermal treatments on surface morphology and chemical composition. The nanostructure and chemical composition of the anodized and annealed Mg substrates were characterized using scanning electron microscopy and energy dispersive X-ray spectroscopy. Our results showed that the nanostructures and chemical composition of anodically-generated oxide layers on Mg are specific to each oxidation process in a 10 M KOH electrolyte. Furthermore, results indicated that anodization durations of two hours generated surface oxide layers with homogeneous topography on the Mg substrates atapplied potentials of 0.5 V, 1.5 V and 2 V.. This study showed a promising approach for creating nanoscale surface features on Mg for improved bioactivity and degradation property.

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Anodization of Magnesium Alloys Using Phosphate Solution

Cited by 4 publications

References 12 publications

TiO₂ Deposition on AZ31 Magnesium Alloy Using Plasma Electrolytic Oxidation

TiO₂ Deposition on AZ31 Magnesium Alloy Using Plasma Electrolytic Oxidation

Chromate-Free Corrosion Protection Strategies for Magnesium Alloys—A Review: Part II—PEO and Anodizing

Surface Characterization of Magnesium Anodized in a 10M KOH Electrolyte

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Anodization of Magnesium Alloys Using Phosphate Solution

Cited by 4 publications

References 12 publications

TiO2 Deposition on AZ31 Magnesium Alloy Using Plasma Electrolytic Oxidation

TiO2 Deposition on AZ31 Magnesium Alloy Using Plasma Electrolytic Oxidation

Chromate-Free Corrosion Protection Strategies for Magnesium Alloys—A Review: Part II—PEO and Anodizing

Surface Characterization of Magnesium Anodized in a 10M KOH Electrolyte

Contact Info

Product

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TiO₂ Deposition on AZ31 Magnesium Alloy Using Plasma Electrolytic Oxidation

TiO₂ Deposition on AZ31 Magnesium Alloy Using Plasma Electrolytic Oxidation