scholarly journals Microstructure and Corrosion Behavior of Composite Coating on Pure Mg Acquired by Sliding Friction Treatment and Micro-Arc Oxidation

Materials ◽  
2018 ◽  
Vol 11 (7) ◽  
pp. 1232 ◽  
Author(s):  
Huihui Cao ◽  
Wangtu Huo ◽  
Shufang Ma ◽  
Yusheng Zhang ◽  
Lian Zhou
Keyword(s):  
Corrosion Resistance ◽  
Sliding Friction ◽  
Corrosion Current ◽  
Grain Structure ◽  
Coarse Grained ◽  
Fine Grained ◽  
Friction Treatment ◽  
Bonding Property ◽  
Micro Arc Oxidation ◽  
Superior Corrosion Resistance

For the purpose of detecting the influence of grain structure of a Mg matrix on the microstructure and corrosion resistance of micro-arc oxidation (MAO) coating, prior to MAO processing, sliding friction treatment (SFT) was adopted to generate a fine-grained (FG) layer on coarse-grained (CG) pure Mg surface. It showed that the FG layer had superior corrosion resistance, as compared to the CG matrix, owing to the grain refinement; furthermore, it successfully survived after MAO treatment. Thus, an excellent FG-MAO coating was gained by combining SFT and MAO. The surface morphology and element composition of FG-MAO and CG-MAO samples did not show significant changes. However, the FG layer favorably facilitated the formation of an excellent MAO coating, which possessed a superior bonding property and greater thickness. Consequently, the modified FG-MAO sample possessed enhanced corrosion resistance, since a lower hydrogen evolution rate, a larger impedance modulus and a lower corrosion current were observed on the FG-MAO sample.

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

Metals ◽  
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.

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

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.

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

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.

Microstructure and Corrosion Resistance of TiN Coating on HSS by Pulsed Bias Cathodic Arc Ion Plating

2011 ◽  
Vol 675-677 ◽  
pp. 1307-1310 ◽  
Author(s):  
Xiao Hong Yao ◽  
Bin Tang ◽  
Lin Hai Tian ◽  
Xiao Fang Li ◽  
Yong Ma
Keyword(s):  
Corrosion Resistance ◽  
High Speed ◽  
High Speed Steel ◽  
Corrosion Current ◽  
Scratch Test ◽  
Grain Structure ◽  
Tin Coating ◽  
Arc Ion Plating ◽  
Ion Plating ◽  
Cathodic Arc

TiN coating with thickness of 2.5μm was deposited on high-speed steel (HSS) substrate by pulsed bias cathodic arc ion plating. The surface and cross-section morphologies, composition depth profile and phase structure were characterized by FESEM, GDOES and XRD, respectively. Scratch test for adhesion evaluation, microhardness test for hardness measurement, and potentiodynamic polarization for corrosion resistance test were used. The results show that the TiN coating exhibits smooth surface, dense columnar grain structure and an obviously preferred orientation of TiN(111). The adhesion of the coating to substrate is exceeded more than 100N. The hardness of the coating is about 26 GPa. The low corrosion current density (Icorr) and rather high corrosion potential (Ecorr) value imply that the TiN coating displays a good corrosion resistance in 0.5mol/l NaCl solution. However, pitting is still existed due to the defects in the coating.

The Research of Micro Arc Oxidation Behavior of the Magnesium Alloy

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 .

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

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.

scholarly journals Microstructure and Properties of Cold Sprayed NiCrAl Coating on AZ91D Magnesium Alloy

Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 193
Author(s):  
Xiangwei Zhao ◽  
Tianshun Dong ◽  
Binguo Fu ◽  
Guolu Li ◽  
Qi Liu ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Cold Spraying ◽  
Corrosion Current ◽  
Wear Volume ◽  
Fatigue Wear ◽  
Az91d Magnesium Alloy ◽  
Superior Corrosion Resistance ◽  
Plasma Sprayed

Herein, a NiCrAl coating was prepared on the AZ91D magnesium alloy by cold spraying technology. The microstructure, wear resistance, and corrosion resistance of the cold sprayed NiCrAl coating were studied and compared with two NiCrAl coatings prepared by plasma spraying. The results showed that the porosity of the two-plasma sprayed NiCrAl coatings was 3.21% and 2.66%, respectively, while that of the cold sprayed NiCrAl coating was only 0.68%. The hardness of the cold sprayed NiCrAl coating (650 HV0.1) was higher than those of the two-plasma sprayed NiCrAl coatings (300 HV0.1, 400 HV0.1). In the abrasion resistance test, the cold sprayed NiCrAl coating showed a lower friction coefficient (0.346), less wear volume (3.026 mm3), and superior wear resistance accordingly compared with the two-plasma sprayed NiCrAl coatings. Moreover, the scanning electron microscopy (SEM) morphology at the bottom of the wear trace of the cold sprayed NiCrAl coating showed a compact mechanically mixed layers (MML) structure, and its wear mechanism was mainly abrasive wear, with some fatigue wear. In the electrochemical test, the corrosion current density of the cold sprayed NiCrAl coating (4.404 × 10−2 A·cm−2) was much lower than those of two plasma sprayed coatings (25.96 A·cm−2, 26.98 A·cm−2), indicating that the cold sprayed NiCrAl coating had superior corrosion resistance. Therefore, preparing a cold sprayed NiCrAl coating is a feasible method to comprehensively improve the wear resistance and corrosion resistance of the AZ91D magnesium alloy.

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

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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