Surface Modification of Mg0.8Ca Alloy via Wollastonite Micro-Arc Coatings: Significant Improvement in Corrosion Resistance

Biodegradable materials are currently attracting the attention of scientists as materials for implants in reconstructive medicine. At the same time, ceramics based on calcium silicates are promising materials for bone recovery, because Ca2+ and Si2+ ions are necessary for the mineralization process, and they take an active part in the formation of apatite. In the presented research, the protective silicate biocoatings on a Mg0.8Ca alloy were formed by means of the micro-arc oxidation method, and the study of their morphology, structure, phase composition, corrosion, and biological properties was carried out. Elongated crystals and pores were uniformly distributed over the surface of the coatings. The coated samples exhibited remarkable anti-corrosion properties in comparison with bare magnesium alloy because their corrosion current decreased 10 times, and their corrosion resistance increased almost 100 times. The coatings did not significantly affect the viability of the cells, even without the additional dilution of the extract, and were non-toxic according to ISO 10993-5: 2009. In this case, there was a significant difference in toxicity of the pure Mg0.8Ca alloy and the coated samples. Thus, the results demonstrated that the applied coatings significantly reduced the toxicity of the alloy.

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Surface Modification of Biomedical MgCa4.5 and MgCa4.5Gd0.5 Alloys by Micro-Arc Oxidation

Materials ◽

10.3390/ma14061360 ◽

2021 ◽

Vol 14 (6) ◽

pp. 1360 ◽

Cited By ~ 1

Author(s):

Piotr Sakiewicz ◽

Krzysztof Piotrowski ◽

Anna Bajorek ◽

Katarzyna Młynarek ◽

Rafał Babilas ◽

...

Keyword(s):

Corrosion Resistance ◽

Corrosion Current ◽

Coating Structure ◽

Corrosion Properties ◽

Ringer’S Solution ◽

Micro Arc Oxidation ◽

Current Densities ◽

The Subject ◽

Polarization Resistances ◽

Anticorrosion Properties

The aim of this work was to characterize the structure and corrosion properties of the MgCa4.5(Gd0.5) alloys surface treated by the micro-arc oxidation (MAO) process. The MgCa4.5 and MgCa4.5Gd0.5 alloy samples were processed by MAO in an electrolyte composed of NaOH (10 g/dm3), NaF (10 g/dm3), NaH2PO4 (5 g/dm3), Na2SiO2·5H2O (10 g/dm3) and water. Two different voltages (120 V and 140 V) were used in the MAO process. The alloys protected by an oxide layer formed in the MAO were then the subject of corrosion resistance tests in an environment simulating the human body (Ringer’s solution). After the experiments, the resulting samples were investigated using SEM, XPS and EDS techniques. The addition of Gd affected the fragmentation of the coating structure, thereby increasing the specific surface; higher voltages during the MAO process increased the number and size of surface pores. Corrosion tests showed that the MgCa4.5Gd0.5 alloys were characterized by low polarization resistances and high corrosion current densities. The studies indicated the disadvantageous influence of gadolinium on the corrosion resistance of MgCa4.5 alloys. The immersion tests confirmed lower corrosion resistance of MgCa4.5Gd0.5 alloys compared to the referenced MgCa4.5 ones. The MgCa4.5 alloy with the MAO coating established at voltage 140 V demonstrated the best anticorrosion properties.

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The Potential of Calcium/Phosphate Containing MAO Implanted in Bone Tissue Regeneration and Biological Characteristics

International Journal of Molecular Sciences ◽

10.3390/ijms22094706 ◽

2021 ◽

Vol 22 (9) ◽

pp. 4706

Author(s):

Shun-Yi Jian ◽

Salim Levent Aktug ◽

Hsuan-Ti Huang ◽

Cheng-Jung Ho ◽

Sung-Yen Lin ◽

...

Keyword(s):

Corrosion Resistance ◽

Calcium Phosphate ◽

Soft Tissues ◽

Salt Spray ◽

Surface Characteristics ◽

Corrosion Current ◽

Biological Properties ◽

Bone Tissue Regeneration ◽

Additional Surgery

Micro arc oxidation (MAO) is a prominent surface treatment to form bioceramic coating layers with beneficial physical, chemical, and biological properties on the metal substrates for biomaterial applications. In this study, MAO treatment has been performed to modify the surface characteristics of AZ31 Mg alloy to enhance the biocompatibility and corrosion resistance for implant applications by using an electrolytic mixture of Ca3(PO4)2 and C10H16N2O8 (EDTA) in the solutions. For this purpose, the calcium phosphate (Ca-P) containing thin film was successfully fabricated on the surface of the implant material. After in-vivo implantation into the rabbit bone for four weeks, the apparent growth of soft tissues and bone healing effects have been documented. The morphology, microstructure, chemical composition, and phase structures of the coating were identified by SEM, XPS, and XRD. The corrosion resistance of the coating was analyzed by polarization and salt spray test. The coatings consist of Ca-P compounds continuously have proliferation activity and show better corrosion resistance and lower roughness in comparison to mere MAO coated AZ31. The corrosion current density decreased to approximately 2.81 × 10−7 A/cm2 and roughness was reduced to 0.622 μm. Thus, based on the results, it was anticipated that the development of degradable materials and implants would be feasible using this method. This study aims to fabricate MAO coatings for orthopedic magnesium implants that can enhance bioactivity, biocompatibility, and prevent additional surgery and implant-related infections to be used in clinical applications.

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Corrosion and Wear Protection through Micro Arc Oxidation Coatings in Aluminum and Its Alloys

Encyclopedia of Aluminum and Its Alloys ◽

10.1201/9781351045636-140000207 ◽

2019 ◽

Author(s):

L. Rama Krishna ◽

G. Sundararajan

Keyword(s):

Corrosion Resistance ◽

Surface Properties ◽

High Hardness ◽

Basic Mechanism ◽

Industrial Applications ◽

Corrosion Properties ◽

Micro Arc Oxidation ◽

Coating Formation ◽

Wear And Corrosion Resistance ◽

Technological Limitations

This article presents the brief overview of fairly recent and eco-friendly micro arc oxidation (MAO) coating technology. The weight-cost-performance benefits in general raised the interest to utilize lightweight materials, especially the aluminum and its alloys. Despite numerous engineering advantages, the aluminum alloys themselves do not possess suitable tribology and corrosion resistance. Therefore, improvements in surface properties are essential to enable developing potential industrial applications. For improving wear and corrosion resistance of Al alloys, the most demanding surface properties are high hardness and chemical inertness. The technical and technological limitations associated with traditional anodizing and hard anodizing processes have been the strongest driving force behind the development of new MAO technology. While presenting the key technological elements associated with the MAO process, the basic mechanism of coating formation and its phase gradient nature is presented. Influence of various process parameters including the electrolyte composition has been discussed. The typical microstructural features and distribution of α- and γ-Al2O3 phases across the coating thickness as a key strategy to form dense coatings with required mechanical, tribological, and corrosion properties which are vital to meet potential application demands are briefly illustrated.

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INFLUENCE OF SURFACTANTS ON THE CORROSION PROPERTIES OF CHROMIUM-FREE ELECTROLESS NICKEL DEPOSIT ON MAGNESIUM ALLOY

Surface Review and Letters ◽

10.1142/s0218625x12500254 ◽

2012 ◽

Vol 19 (03) ◽

pp. 1250025 ◽

Cited By ~ 2

Author(s):

JOTHI SUDAGAR ◽

RUAN DEWEN ◽

YAQIN LIANG ◽

RASU ELANSEZHIAN ◽

JIANSHE LIAN

Keyword(s):

Corrosion Resistance ◽

Magnesium Alloy ◽

Electroless Nickel ◽

Corrosion Current ◽

Immersion Test ◽

Electrochemical Polarization ◽

Nickel Deposit ◽

Corrosion Properties ◽

Positive Direction ◽

Polarization Test

Influence of surfactants on the corrosion properties of chromium-free electroless nickel deposit were investigated on AZ91D magnesium alloy. The corrosion tests were carried out by immersion test (1 M HCl) and electrochemical polarization test (3.5 wt% NaCl ). The surfactants in the electroless nickel bath increases the corrosion resistance properties of the deposit on the magnesium alloy. In addition, smoothness and amorphous plus nano-crystalline phase were increased and accounted for the significant corrosion resistance. As a consequence, the corrosion potential moved towards the positive direction and the corrosion current density decreased. The immersion tests also provided the same trend as that of electrochemical polarization test. On the whole, the study concluded that corrosion resistance was enhanced by including a surfactant in the electroless deposits on magnesium alloy.

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Tribological and Corrosive Properties of Tin/AlN Multilayer Film

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.560-561.837 ◽

2012 ◽

Vol 560-561 ◽

pp. 837-841

Author(s):

Pu Hong Tang ◽

Jie Mao ◽

Chong You Feng

Keyword(s):

Corrosion Resistance ◽

Coefficient Of Friction ◽

Gas Flow ◽

Multilayer Film ◽

Corrosion Current ◽

Multilayer Films ◽

Nitrogen Gas ◽

Corrosion Properties ◽

Wear Rates ◽

The Coefficient Of Friction

TiN/AlN nanoscale multilayer films were deposited by pulsed laser ablation on silicon, with different argon and nitrogen gas flow rates. The total thickness of the TiN/AlN multilayer film was approximately 1μm. The friction and corrosion properties were studied by tribological and corrosive tests. In tribological tests, ball-on-disc was used to determine coefficients of friction and wear rates. The coefficient of friction against a Si3N4 ball varied considerably between films, as does the wear rate. The lowest coefficient of friction μ=0.97 was shown at sample 1, whereas the other three multilayer films were ranged from 1.0 to 1.5. In corrosion test, the anodic polarization characteristics were measured in a 3.5% NaCl solution at room temperature to examine the corrosion resistance. The potentiodynamic polarization measurements showed that for all the multilayer films the corrosion potential shift to higher values, and the corrosion current density decreased with increasing of nitrogen gas flow rate, which indicate a higher nitrogen partial pressures lead to a better corrosion resistance.

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The Effects of Magnetic Field on Micro-Arc Oxidation Ceramic Coating on Magnesium Alloys

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.960-961.143 ◽

2014 ◽

Vol 960-961 ◽

pp. 143-147

Author(s):

Jun Zhao ◽

Jian Jun Xi ◽

Zhi Gang Wang ◽

Chun Ping Zhao

Keyword(s):

Magnetic Field ◽

Corrosion Resistance ◽

Electron Microscope ◽

Friction Coefficient ◽

Ceramic Coating ◽

Ceramic Coatings ◽

Oxidation Method ◽

Polarization Test ◽

Micro Arc Oxidation ◽

Scanning Electron

Ceramic coatings were prepared on ZM5 magnetism substrate by micro-arc oxidation method with and without magnetism filed in silicate electrolyte. The morphology of the MAO coatings was investigated by scanning electron microscope (SEM). The friction coefficient of the MAO coatings prepared with magnetism is about 0.2 and more stable than the coatings prepared without magnetism. The polarization test indicated that the coating prepared with magnetism has better corrosion resistance.

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Double Sealing of Ultrasonic Micro-Arc Oxidation Coating on Pure Magnesium by Nano-SiO2 Particles and SiO2 Sol Sealing Agent

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1030-1032.48 ◽

2014 ◽

Vol 1030-1032 ◽

pp. 48-51

Author(s):

Wei Wei Sun ◽

Mu Qin Li ◽

Yan Gao ◽

Jiang Liu

Keyword(s):

Corrosion Resistance ◽

Bone Growth ◽

Corrosion Current ◽

Pure Magnesium ◽

Infrared Spectrometry ◽

Nano Sio2 ◽

Micro Arc Oxidation ◽

Sio2 Particles ◽

Si Content ◽

Sealing Coating

A double sealing coating was prepared on ultrasonic micro-arc oxidized pure magnesium substrate by adding nano-SiO2 particles as additive in the plating solution and coating SiO2 sol as sealing agent. The bonding characters of SiO2 sol was analyzed by Fourier transformed infrared spectrometry (FTIR). The compositions and morphology of seal coating were characterized by energy-dispersive X-ray spectroscopy (EDS) and scanning electron microscopy (SEM), respectively. The corrosion resistance of the micro-arc oxidized and the sealed pure magnesium substrate were studied. The results showed that the Si content increased gradually with the addition of nano-SiO2 particles and the SiO2 sol sealing. It was benefit to create bioactive MgSiO3, which promoted the bone growth. The double sealed pure magnesium had a self-corrosion potential shifted positively by 60mV as well as a self-corrosion current density decreased by a half in a 3.5wt% NaCl solution, showing good corrosion resistance.

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Influence of EDTA-2Na Concertration on the Microstructure and Corrosion Behaviors of Mg-Al-Y Alloy

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.727-728.201 ◽

2015 ◽

Vol 727-728 ◽

pp. 201-204

Author(s):

Yun Long Zhang ◽

Mu Qin Li ◽

Ping Liao ◽

Yu Min Zhang

Keyword(s):

Corrosion Resistance ◽

Electrolyte Solution ◽

Oxidation Process ◽

Corrosion Current ◽

Positive Potential ◽

Micro Arc Oxidation ◽

Corrosion Behaviors ◽

Oxidation Technology ◽

Structural Surface ◽

Polarisation Measurements

In this paper,the micro-arc oxidation technology were utilized to fabricated the oxidation coating in order to resolve the corrosion resistance of the Mg-Al-Y alloy. The EDTA-2Na solution was introduced into the electrolyte solution for improving the coating corrosion properties.After the micro-arc oxidation process, phase structural, surface morphology and corrosion resistance of the MAO coating of Mg-Al-Y alloy were performed by XRD, SEM and Potentiodynamic polarisation measurements. The introduce of EDTA-2Na in the electrolyte solution improve the positive potential and reduced the corrosion current, which would improve the corrosion resistance properties of the Mg-Al-Y alloy.

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The Research of Micro Arc Oxidation Behavior of the Magnesium Alloy

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.803.191 ◽

2013 ◽

Vol 803 ◽

pp. 191-195

Author(s):

Yun Long Zhang ◽

Mu Qin Li ◽

Yu Min Zhang ◽

Ming Hu

Keyword(s):

Corrosion Resistance ◽

Phase Composition ◽

Magnesium Alloy ◽

Surface Morphology ◽

Electrolyte Solution ◽

Oxidation Behavior ◽

Corrosion Current ◽

Positive Potential ◽

Micro Arc Oxidation ◽

Oxidation Technology

The ceramics coating hadobtained by the micro arc oxidation technology in order to resolve thecorrosion resistance of the Mg alloy.The phase composition, surface morphology,gained weight and polarization behavior of the micro arc oxidation coating wasinvestigated in details. After the introduce of the sodiumcitrate in the electrolyte solution, thespecimen had high relatively positive potential and low corrosion current, sodoped sodium citratewould improve the corrosion resistance properties of the Mg alloy .

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