Preparation and properties of composite MAO/ECD coatings on magnesium alloy

Zhao, Qing; Guo, X. B.; Dang, Xiaoqian; Hao, Jianmin; Lai, Jianghua; Wang, Kunzheng

doi:10.1016/j.colsurfb.2012.07.040

Cited by 78 publications

(32 citation statements)

References 33 publications

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“…Moreover, some nondegradable oxides, such as Mg(OH) 2 and MgO, may be produced during the procedure. 32,33 In order to avoid these drawbacks, we fabricate a Mg-based biomedical coating by conducting electrodeposition in organic solution. It is another advantage of our investigation, since the magnesium alloy can maintain its original surface composition without a chemical reaction with an electrolyte during the electrodeposition procedure.…”

Section: Introductionmentioning

confidence: 99%

One-Step Electrodeposition of Self-Assembled Colloidal Particles: A Novel Strategy for Biomedical Coating

et al. 2014

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A novel biomedical coating was prepared from selfassembled colloidal particles through direct electrodeposition. The particles, which are photo-cross-linkable and nanoscaled with a high specific surface area, were obtained via self-assembly of amphiphilic poly(γ-glutamic acid)-g-7-amino-4-methylcoumarin (γ-PGA-g-AMC). The size, morphology, and surface charge of the resulting colloidal particles and their dependence on pH, initial concentrations, and UV irradiation were successfully studied. A nanostructured coating was formed in situ on the surface of magnesium alloys by electrodeposition of colloidal particles. The composition, morphology, and phase of the coating were monitored using Fourier transform infrared spectroscopy, energy-dispersive X-ray spectroscopy, scanning electron microscopy, and X-ray diffraction. The corrosion test showed that the formation of the nanostructured coating on magnesium alloys effectively improved their initial anticorrosion properties. More importantly, the corrosion resistance was further enhanced by chemical photo-cross-linking. In addition, the low cytotoxicity of the coated samples was confirmed by MTT assay against NIH-3T3 normal cells. The contribution of our work lies in the creation of a novel strategy to fabricate a biomedical coating in view of the versatility of self-assembled colloidal particles and the controllability of the electrodeposition process. It is believed that our work provides new ideas and reliable data to design novel functional biomedical coatings.

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Section: Introductionmentioning

confidence: 99%

One-Step Electrodeposition of Self-Assembled Colloidal Particles: A Novel Strategy for Biomedical Coating

et al. 2014

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“…With the addition of 5 wt.% Ca, the current density (corrosion rate) displayed a decreasing trend, and the Mg-5Ca alloy showed increasing corrosion potential and decreasing current density. These changes improve corrosion resistance [36]. Consequently, because of decreasing particle size, the added Ca stacks as a precipitate on the grain boundary, acting as a barrier to corrosion and thus increasing corrosion resistance [37].…”

Section: Potentiodynamic Testmentioning

confidence: 99%

“…Formation of a chemically passive layer weakens the exchange current and hydrogen generation, which can inhibit the formation of Mg 2 Ca and stabilize the protective layer on the surface. The decreased Ca crystal grain size in the Mg-5Ca alloy and the formation of Mg 2 Ca, are important factors that affect the size and distribution of the secondary phase and reduce the rate of hydrogen generation [36]. Figure 6 shows representative SEM images of the corrosion products formed on the surface of the pure Mg and Mg-Ca alloys after 14 days of immersion.…”

Section: Amount and Rate Of Hydrogen Emissionmentioning

confidence: 99%

“…The corrosion products consisted mostly of a thin layer of MgO and Mg(OH) 2 , which correlated with a high exchange current in and on the surface of the Tas-SBF solution. Also, the Mg-5Ca alloy, which possessed the Mg 2 Ca secondary phase, easily destroyed the Mg(OH) 2 passive state layer, accelerating the emission of Mg 2+ and continuously reacting with Cl − to create MgCl 2 [36]. …”

Section: Amount and Rate Of Hydrogen Emissionmentioning

confidence: 99%

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Biological Evaluation of Anodized Biodegradable Magnesium-Calcium Alloys

Kim

Lee

et al. 2016

Acta Phys. Pol. A

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The objective of this study was to evaluate the biocompatibility of studied binary magnesium-calcium (Mg-Ca) alloys for biodegradable intraosseous implants. Mg is necessary for health and is a non-toxic biodegradable material that decomposes naturally in the body. Nevertheless, Mg has been implicated in problems including diminished physical properties and corrosion resistance when degradation is too rapid prior to bone healing. This study has explored the effect of Ca on the corrosion resistance and biological evaluation after anodizing treatment with different contents of Ca alloy. Binary Mg-0.5Ca, Mg-1Ca and Mg-5Ca alloys were prepared by the casting method under an argon atmosphere and cut into disc-shaped pieces. Pure Mg alloy was used as the control. Anodic oxidation was performed for 15 minutes at a voltage of 120 V using an electrolyte solution containing Ca gluconate, sodium hexametaphosphate, and sodium hydroxide at room temperature. Corrosion resistance was analyzed using a corrosion tester. After a hydrogen evolution test, the surface pattern and phase changes were observed on a scanning electron microscop (SEM) and energy dispersive spectroscop (EDS). Microscopic evaluation of the adhesion and cell biological functions of Mg was conducted by observing the response of human fetal osteoblastic 1.19 cells with regard to changes in surface film properties, depending on the amount of Ca. Our results support the view that in Mg-xCa alloys (x = 0.5, 1, 5 wt.%) treated using anodic oxidation, the increasing Ca content controls the rate of decomposition and improves corrosion resistance.

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“…Moreover, since the solubility limit of Ca in Mg is relatively low (0.98 wt.%), Ca is released during solidification, which leads to supersaturation of Ca at the surface. The remaining solute suppresses the growth of the grains [36]. Figure 3 graphically depicts the results of surface roughness measurements conducted to examine the effect of Ca in each alloy.…”

Section: Analysis Of Surface Coating By Anodizingmentioning

confidence: 99%

Evaluation of Surface Characteristics and Physical Properties on Biodegradable Magnesium-Calcium Alloys by Anodic Oxidation

et al. 2016

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The purpose of this study was to determine the effect of calcium (Ca) on the surface characteristics and physical properties of magnesium-calcium alloys after anodization. A novel binary alloy Mg-xCa (in which x = 0.5, 1, or 5 wt.%) was cast by combining magnesium (99.9%) and calcium (99.9%) in an argon gas (99.99%) atmosphere. A magnesium alloy rod having a diameter of 15 mm was cut into discs, each 2 mm thick. The specimens were subjected to anodic oxidation at 120 V for 15 minutes at room temperature in an electrolyte solution consisting of calcium gluconate, sodium hexametaphosphate, and sodium hydroxide. Surface and cross-sectional morphological changes were observed using scanning electron microscopy, and the microstructures and phases were detected by means of X-ray diffraction. Hardness and surface roughness were assessed by means of a Vickers hardness tester and a surface roughness meter, respectively. The results show that the physical properties of these magnesiumcalcium alloys have been improved, because it was possible to control the dissolution rate according to the amount of calcium added.

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Preparation and properties of composite MAO/ECD coatings on magnesium alloy

Cited by 78 publications

References 33 publications

One-Step Electrodeposition of Self-Assembled Colloidal Particles: A Novel Strategy for Biomedical Coating

One-Step Electrodeposition of Self-Assembled Colloidal Particles: A Novel Strategy for Biomedical Coating

Biological Evaluation of Anodized Biodegradable Magnesium-Calcium Alloys

Evaluation of Surface Characteristics and Physical Properties on Biodegradable Magnesium-Calcium Alloys by Anodic Oxidation

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