Investigation on Corrosion Resistance and Formation Mechanism of a P–F–Zr Contained Micro-Arc Oxidation Coating on AZ31B Magnesium Alloy Using an Orthogonal Method

Zhu, Yuanyuan; Chang, Wenhui; Zhang, Shufang; Song, Yingwei; Huang, Huade; Zhao, Rongfang; Li, Guoqiang; Zhang, Rongfa; Zhang, Yijia

doi:10.3390/coatings9030197

Cited by 13 publications

(3 citation statements)

References 47 publications

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“…Recently, a number of works have applied orthogonal experiment designs in order to evaluate the interaction of several electrolyte components, such as K 2 ZrF 6 and EDTA-Na, with the electrical parameters. Both of these additives are being increasingly used in new PEO coating developments [ 205 , 206 , 207 , 208 ]; K 2 ZrF 6 as a source of Zr, with the aim of forming ZrO 2 in the coating from particle-free electrolytes, and EDTA-Na as a complexing agent to stabilize cations of interest in the electrolyte [ 193 ]. K 2 ZrF 6 is problematic on its own in terms of the surface passivation and coating growth that occur due to its acidity; however, it can successfully form self-sealing coatings when combined with other additives, such as phytic acid and ammonium fluoride [ 206 ].…”

Section: Effect Of Energy Input and Electrolyte Composition On Coatin...mentioning

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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Section: Effect Of Energy Input and Electrolyte Composition On Coatin...mentioning

confidence: 99%

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

et al. 2022

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“…As a result, many methods for improving the corrosion resistance of Mg-Li alloys have been used and developed. Among them, surface treatment is the most common method of optimizing the properties of the alloys, including chemical conversion coatings, [7][8][9] micro-arc oxidation (MAO), [10][11][12] organic coating, 13 cold spraying, 14 and composite coatings. [15][16][17] As for various coatings or films, layered double hydroxide (LDH) has attracted the attention of many researchers owing to its combination of self-healing, self-cleaning, and corrosion-inhibiting properties.…”

Section: Introductionmentioning

confidence: 99%

Investigating the microstructures and properties of Mg‐Al LDH film‐coated Mg‐Li alloy: Effect of hydrothermal temperature

Zhang

Hou

et al. 2022

Int J Applied Ceramic Tech

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Magnesia-alumina layered double hydroxide (Mg-Al LDH) films grown in situ on LA43M magnesium-lithium (Mg-Li) alloy were synthesized utilizing the hydrothermal method. Scanning electron microscopy (SEM), energy-dispersive spectrometry (EDS), and X-ray diffraction (XRD) were used to characterize the surface morphologies, composition, and phase of the Mg-Al films. The corrosion resistance of the Mg-Al films was estimated via immersion experiment and hydrogen evolution test, and the tribological properties were investigated using tribological wear tests. The results showed that the thickness of the Mg-Al LDH film enhanced, and the size of the LDH sheets increased as the hydrothermal temperature raised, resulting in the improvement of the corrosion and wear resistance. When the hydrothermal temperature reached 110 • C, interlayer anions were loaded the most, and the film achieved the optimal thickness. The Mg-Al LDH film had the optimum corrosion resistance and tribological properties. At this point, the weight loss of the film was 1.3560 mg⋅cm -2 , and the average friction coefficient was .149. It demonstrated that synthesizing Mg-Al LDH at a hydrothermal temperature of 110 • C was an effective approach to improve the corrosion resistance of LA43M.

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“…When applying a high voltage between two electrodes, the intense spark discharge would take place on the surface of the specimens (Patcas and Krysmann, 2007;Wang et al, 2011). Due to the local high temperature caused by discharge and the involvement of thermal-, plasma-, and electro-chemical reactions in the electrolyte, ceramic-like coatings can be fabricated on the surfaces of the specimens with good compactness, corrosion resistance and wear resistance (Lee et al, 2019;Li et al, 2019;Zhu et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

Properties of Micro-Arc Oxidation Coating Fabricated on Magnesium Under Two Steps Current-Decreasing Mode

Wang

Zhang

et al. 2020

Front. Mater.

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A concept of two-steps current-decreasing mode derived from constant current mode was developed to fabricate micro-arc oxidation (MAO) coatings on ZK60 magnesium alloy in a dual electrolyte system. The growth characteristics of coatings were analyzed by voltage-time curves, and the coating microstructures were characterized by means of scanning electron microscopy. Meanwhile, the roughness, corrosion behavior, and microhardness of MAO coatings were investigated. The results show that the MAO coatings exhibit a smooth and compact surface, and have improved hardness, higher thickness, smaller roughness, and uneven distribution of holes. Such positive characteristics result in improved corrosion resistance of MAO coatings. The coating produced under the two-steps current mode of "1.2-0.6A" shows a smaller corrosion rate of 0.1559 g/m 2 •h compared with the one produced under the other mode. The results of nanoscratch tests show that the coating fabricated by "1.2-0.6 A" mode has strong bond strength with the substrate. Under this optimized mode, the MAO process also has the lowest energy consumption of 49.8 W/(dm 2 •µm).

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Investigation on Corrosion Resistance and Formation Mechanism of a P–F–Zr Contained Micro-Arc Oxidation Coating on AZ31B Magnesium Alloy Using an Orthogonal Method

Cited by 13 publications

References 47 publications

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

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

Investigating the microstructures and properties of Mg‐Al LDH film‐coated Mg‐Li alloy: Effect of hydrothermal temperature

Properties of Micro-Arc Oxidation Coating Fabricated on Magnesium Under Two Steps Current-Decreasing Mode

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