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

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 HF-SCG Immersion Treatment on Corrosion Resistance of the Ultrasonic Micro-Arc Oxidation Bio-Coating on Pure Magnesium

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.633.402 ◽

2014 ◽

Vol 633 ◽

pp. 402-405

Author(s):

Mu Qin Li ◽

Jiang Liu ◽

Jun Gang Li ◽

Ding Sen Cai ◽

Yong Hui Zhao

Keyword(s):

Corrosion Resistance ◽

Corrosion Potential ◽

Electrochemical Corrosion ◽

Corrosion Current ◽

Ceramic Coatings ◽

Pure Magnesium ◽

Electrolyte System ◽

Order Of Magnitude ◽

Micro Arc Oxidation ◽

Compound Coatings

Ceramic coatings were fabricated on pure magnesium in silicate electrolyte system by ultrasonic micro-arc oxidation (UMAO) process, and then silica sol (CSG) and HF-CSG treatment were carried out on micro-arc oxidation coatings. The corrosion potential (Ecorr) and corrosion current density (Icorr) of the compound coatings were analyzed by electrochemical corrosion workstation. The corrosive morphology of the coatings was observed by scanning electron microscopy (SEM). Results showed that the Ecorr of the coating with CSG and HF-CSG treatment increased by 55 mV and 69 mV respectively in comparison with that of single UMAO coating, and its Icorr reduced an order of magnitude, which had enhanced the corrosion resistance.

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

Metals ◽

10.3390/met11050754 ◽

2021 ◽

Vol 11 (5) ◽

pp. 754

Author(s):

Mariya B. Sedelnikova ◽

Anna V. Ugodchikova ◽

Tatiana V. Tolkacheva ◽

Valentina V. Chebodaeva ◽

Ivan A. Cluklhov ◽

...

Keyword(s):

Corrosion Resistance ◽

Corrosion Current ◽

Biological Properties ◽

Mineralization Process ◽

Corrosion Properties ◽

Oxidation Method ◽

Significant Difference ◽

Structure Phase ◽

Micro Arc Oxidation ◽

Calcium Silicates

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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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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Corrosion Resistance of Mg-4Zn Alloy with Amorphous Micro-Arc Oxidation Coating in Simulated Body Fluid

Materials Science Forum ◽

10.4028/www.scientific.net/msf.852.1325 ◽

2016 ◽

Vol 852 ◽

pp. 1325-1333

Author(s):

Li Chen Zhao ◽

Shuang Jin Liu ◽

Yu Min Qi ◽

Chun Xiang Cui

Keyword(s):

Corrosion Resistance ◽

Simulated Body Fluid ◽

Current Density ◽

Polarization Resistance ◽

Body Fluid ◽

Corrosion Current Density ◽

Corrosion Current ◽

Metal Substrate ◽

Electrochemical Measurements ◽

Micro Arc Oxidation

A binary Mg-4Zn alloy was fabricated as a potential degradable biomaterial. To improve the corrosion resistance of Mg-4Zn alloy, an amorphous micro-arc oxidation (MAO) coating was prepared on the Mg-4Zn substrate. Electrochemical measurements and immersion tests were employed to evaluate the corrosion resistance of the specimen in simulated body fluid (SBF). Electrochemical measurements show that the Mg-4Zn alloy covered with a MAO coating has a much lower corrosion current density and a much greater polarization resistance. Immersion tests suggest that the degradation of Mg-4Zn substrate is relatively serious during the initial 8 h of immersion although it has been protected by a MAO coating. When most micro-pores within the MAO coating have been filled with precipitates resulted from the corrosion of the metal substrate, the degradation of the Mg-4Zn substrate is significantly delayed.

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Correlation between Applied Voltage and Electrochemical Properties of Micro Arc Oxidation Coatings Formed on AZ31B Magnesium Alloy

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.849.32 ◽

2013 ◽

Vol 849 ◽

pp. 32-37

Author(s):

Xiang Hua Song ◽

Jian Hong Lu ◽

Xi Jiang Yin ◽

Jian Ping Jiang ◽

Annie Tanlai Kuan ◽

...

Keyword(s):

Corrosion Resistance ◽

Electrochemical Properties ◽

Applied Voltage ◽

Coating Layer ◽

Electrical Parameter ◽

Corrosion Current ◽

Coating Properties ◽

Voltage Range ◽

Atomic Force ◽

Micro Arc Oxidation

The correlation between the electrical parameter of applied voltage and the coating properties, especially the electrochemical properties of micro arc oxidation coating layer was studied in environmental friendly electrolyte under single-polar pulse power supply. The coating surface morphology and corrosion resistance was characterized by atomic force microscope (AFM) and electrochemical method. The coating thickness and the pores in the coating layer grow with increasing the applied voltage; also the surface becomes rougher at higher voltages. In the voltage range of 240 V to 320 V, the relative optimal voltage parameter is 260 V, which presents the smallest corrosion current density, three orders of magnitude lower than that of bare Mg substrate and the highest coating impedance value among all coatings. With increasing applied voltage from 240 V to 260 V, the corrosion resistance was improved significantly; then decreased slightly at higher voltages of 280 V to 320 V. The impedance spectroscopy fitting results show that the voltage parameter has more effect on the inner layer than on the outer layer of micro arc oxidation coatings and the coating property is more dependent on the compact inner layer.

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Corrosion and Wear Properties of h-BN Modified TC4 Titanium Alloy Micro-Arc Oxide Coatings

Surface Innovations ◽

10.1680/jsuin.21.00070 ◽

2022 ◽

pp. 1-10

Author(s):

X W Chen ◽

P Ren ◽

D F Zhang ◽

J Hu ◽

C Wu ◽

...

Keyword(s):

Wear Resistance ◽

Corrosion Resistance ◽

Titanium Alloy ◽

Hexagonal Boron Nitride ◽

Corrosion Current ◽

Ceramic Coatings ◽

Element Distribution ◽

Wear Properties ◽

Tc4 Titanium Alloy ◽

Micro Arc Oxidation

In this study, ceramic coatings were prepared on the surface of TC4 titanium alloy by micro-arc oxidation (MAO). The morphology, element distribution and phase composition of MAO coatings were analyzed by SEM, EDS, XRD and other analytical methods. The effect of hexagonal boron nitride(h-BN) doping on wear resistance and corrosion resistance of micro-arc oxidation layer was studied. The results show that the coating is mainly composed of rutile TiO2, anatase TiO2 and a small amount of h-BN. Furthermore, the composite coating containing h-BN was less porous than particle-free coating. The test results show that h-BN doping slightly affects the hardness of the MAO coating, and it is helpful in improving the thickness, corrosion resistance and wear resistance of the coatings. When the amount of h-BN is 3 g/L, the corrosion current density of the coating is the smallest; When the addition of h-BN is 1.5 g/L, the friction coefficient of the coating is the smallest. The wear mechanism was adhesive wear, accompanied by slight abrasive wear.

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The Preparation and Properties of the Brown Film by Micro-arc Oxidized on In-Situ TiB2/7050Al Matrix Composites

Coatings ◽

10.3390/coatings10070615 ◽

2020 ◽

Vol 10 (7) ◽

pp. 615

Author(s):

Cunjuan Xia ◽

Jie Huang ◽

Jiongming Tao ◽

Shuyang Wang ◽

Ling Cai ◽

...

Keyword(s):

Corrosion Resistance ◽

Corrosion Potential ◽

Corrosion Current ◽

Alkaline Electrolyte ◽

Matrix Composites ◽

Al Composite ◽

White Film ◽

Alkaline Electrolytes ◽

Micro Arc Oxidation

The brown or grayish-white color films were prepared by the micro-arc oxidation (MAO) method on in-situ TiB2/7050Al composites using these alkaline electrolytes with/without KMnO4 as an additive. The microstructure, elemental composition, chemical state and corrosion behavior have been investigated by the microstructure characterizations and electrochemistry measurements on the MAO films comparatively. The results indicated that a brown film was obtained via adding KMnO4 into the alkaline electrolyte. The coloration mechanism of the brown color can be ascribed to the existence of MnO inside the film. Furthermore, the initiation of corrosion to the Al composite was intensively hindered by the brown MAO film. Compared with the Al substrate and grayish-white film, the brown MAO film exhibited the elevated corrosion potential and reduced corrosion current. Therefore, the brown film has presented an optimized corrosion resistance for the composite.

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