scholarly journals Formation and Corrosion Resistance of Micro-Arc Oxidation Coating on Equal-Channel Angular Pressed AZ91D Mg Alloy

Metals ◽  
2016 ◽  
Vol 6 (12) ◽  
pp. 308 ◽  
Author(s):  
Aibin Ma ◽  
Fumin Lu ◽  
Qi Zhou ◽  
Jinghua Jiang ◽  
Dan Song ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Mg Alloy ◽  
Micro Arc Oxidation

Micro Arc Oxidation of AZ91 Mg Alloy for Improved Corrosion Resistance

2011 ◽  
Vol 312-315 ◽  
pp. 877-881 ◽  
Author(s):  
H.G. Yavuz ◽  
M. Gunyuz ◽  
Isa Metin Ozkara ◽  
Murat Baydogan ◽  
Huseyin Cimenoglu
Keyword(s):  
Corrosion Resistance ◽  
Surface Topography ◽  
Xrd Analysis ◽  
Processing Parameters ◽  
Mg Alloy ◽  
X Ray Diffraction ◽  
Corrosive Solution ◽  
Weight Losses ◽  
Before And After ◽  
Micro Arc Oxidation

AZ91 Mg alloy was subjected to the micro arc oxidation process by using different processing parameters. Following oxidation, surface topography and qualitative phase analysis were made by tabletop digital microscopy and X-ray diffraction (XRD) analysis. In order to evaluate the relative corrosion resistance of the samples that were oxidized in different parameters, the samples were immersed in a corrosive solution for 6 days and the weight losses before and after the corrosion tests were compared. Relative corrosion resistance of the samples was evaluated on the basis of surface topography.

scholarly journals Effect of the second-step voltages on the structural and corrosion properties of silicon–calcium–phosphate (Si–CaP) coatings on Mg–Zn–Ca alloy

2018 ◽  
Vol 5 (10) ◽  
pp. 172410 ◽  
Author(s):  
Jinhe Dou ◽  
Yupeng Zhao ◽  
Lu Lu ◽  
Guochao Gu ◽  
Huijun Yu ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Degradation Rate ◽  
Electrochemical Techniques ◽  
Orthopedic Implants ◽  
Mg Alloy ◽  
Second Step ◽  
Corrosion Properties ◽  
Slow Increase ◽  
Micro Arc Oxidation ◽  
Sbf Solution

The applications of magnesium (Mg) alloys as biodegradable orthopedic implants are mainly restricted due to their rapid degradation rate in the physiological environment. In this study, Si–CaP micro-arc oxidation (MAO) coatings were prepared on a Mg–Zn–Ca alloy by a second-step MAO process at different voltages in order to decrease the degradation rate and increase the bioactivity of the alloy. The microstructure and morphology of the samples were characterized using XRD, FT-IR SEM and EDS. The degradation behaviours of samples were evaluated using electrochemical techniques, and immersion tests in simulated body fluid (SBF). The results indicate that the morphology of the Si–CaP coatings changed significantly with the increase in Ca/P ratio as the second-step voltage increased. The Si–CaP containing coating produced at 450 V could significantly decrease the degradation rate of Mg and caused a slow increase in pH of the SBF solution. The haemolysis test concluded that the coating C3 did not cause a haemolytic reaction. The corrosion resistance of Mg alloy was greatly improved with the Si–CaP coatings, and the Mg alloy with Si–CaP coating prepared at 450 V had the best corrosion resistance, which indicates that the Si–CaP coatings are promising for improving the biodegradation properties of Mg-based orthopedic implants. Haemolysis tests indicated that the Si–CaP coating prepared at 450 V conforms to the given standard (YY/T0127.1-93).

Fabrication and corrosion resistance of a hydrophobic micro-arc oxidation coating on AZ31 Mg alloy

2015 ◽  
Vol 90 ◽  
pp. 402-412 ◽  
Author(s):  
Xue-jun Cui ◽  
Xiu-zhou Lin ◽  
Chun-hai Liu ◽  
Rui-song Yang ◽  
Xing-wen Zheng ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Mg Alloy ◽  
Az31 Mg Alloy ◽  
Micro Arc Oxidation

New Method for the Corrosion Resistance of AZ31 Mg Alloy with a Porous Micro-Arc Oxidation Membrane as an Ionic Corrosion Inhibitor Container

Langmuir ◽  
2018 ◽  
Vol 35 (5) ◽  
pp. 1134-1145 ◽  
Author(s):  
Zhaoxia Li ◽  
Wenbin Yang ◽  
Qiangliang Yu ◽  
Yang Wu ◽  
Daoai Wang ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Inhibitor ◽  
New Method ◽  
Mg Alloy ◽  
Az31 Mg Alloy ◽  
Micro Arc Oxidation

Effects of Interaction of (NaPO3)6 and NaH2PO4 on Ca/P of MAO Bio-Ceramic Coating of ZK60 Mg Alloy

2013 ◽  
Vol 745-746 ◽  
pp. 21-27
Author(s):  
Cui Ling Du ◽  
Jing Chen ◽  
Bin Bin Cao ◽  
Lei Xu ◽  
Sheng Lu
Keyword(s):  
Corrosion Resistance ◽  
Ceramic Coating ◽  
Energy Dispersive Spectrometer ◽  
Mg Alloy ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Orthogonal Experiments ◽  
Micro Arc Oxidation ◽  
Evolution Phase

Micro-arc oxidation (MAO) process was conducted on ZK60 Mg alloy in a basic biologic electrolyte composed of silicate by addition of (NaPO3)6 and NaH2PO4. The microstructural evolution, phase composition and in vitro corrosion resistance of the coating were investigated by means of scanning electron microscopy (SEM) coupled with an energy dispersive spectrometer (EDS) and X-ray diffraction (XRD). The results revealed that bioactive elements Mg, Ca, P and Si were remained in the bio-ceramic coating which can be prepared in suitable biologic electrolyte. For the interaction of (NaPO3)6 and NaH2PO4 , the Ca/P molar ratio of the coating in the optimized biologic electrolyte reached to 1.24 by L9 (34) orthogonal experiments. Compared with the bare ZK60 Mg alloy, the corrosion resistance of the optimized sample in 37 Ringers solution was improved by 4 orders.

Growth Characteristics, Microstructure and Corrosion Resistance of Micro-Arc Oxidation Coatings Fabricated on ZK60 Mg Alloy under Two Steps Voltage-Increasing Mode

2011 ◽  
Vol 337 ◽  
pp. 101-105 ◽  
Author(s):  
Sheng Lu ◽  
Li Tang ◽  
Xi Zhi Jiang ◽  
Ze Xin Wang ◽  
Jing Chen
Keyword(s):  
Corrosion Resistance ◽  
Arc Discharge ◽  
Growth Characteristic ◽  
Growth Characteristics ◽  
Mg Alloy ◽  
Constant Voltage ◽  
Corrosion Resistant ◽  
Voltage Mode ◽  
Micro Arc Oxidation ◽  
Characteristic Microstructure

A concept of two steps voltage increasing mode derived from constant voltage mode was developed to fabricate micro-arc oxidation (MAO) coatings on ZK60 Mg alloy. Growth characteristic, microstructure and corrosion resistance of coatings were investigated and compared with the constant voltage mode. An additional and distinguishing stage is found and regarded as a coating regrowth stage playing an important role on coating thickness. Effects of increase value of voltage were also investigated. It shows that rougher and thicker coating is formed for higher value of voltage. And it is more likely to induce destructive arc discharge for excessive increase value, thus leads to a looser and less corrosion resistant coating. The coating formed under two steps voltage-increasing mode of 280-360V exhibits the best corrosion resistance.

Research and Application of Micro-Arc Oxidation Technology on Magnesium Alloy Motorcycle Key Parts

2014 ◽  
Vol 496-500 ◽  
pp. 63-70
Author(s):  
Xi Di Chen ◽  
Qi Zhou Cai ◽  
Zhi Wei Deng ◽  
Li Song Yin
Keyword(s):  
Corrosion Resistance ◽  
Layer Structure ◽  
Orthogonal Experiment ◽  
Amorphous Material ◽  
Mg Alloy ◽  
Additive Concentration ◽  
Corrosion Medium ◽  
Immersion Corrosion ◽  
Micro Arc Oxidation ◽  
Oxidation Technology

The micro-arc oxidation process parameters of AZ91D Mg alloy and Na2WO4 concentration were optimized by orthogonal experiment. SEM, EDX, XRD, potentiodynmic polarization and immersion corrosion test were carried out to investigate the morphologies, phase composition and corrosion resistance of the MAO coatings. The results shown that the MAO coating are mainly composed of MgOMg2SiO4MgAl2O4,MgWO4 and a small amount of amorphous material as well as with a double layer structure, outer loose and inner denser, the proper parameters and additive concentration were: 300Hz,5.0A/dm2,50%/50% and 2.0g/l Na2WO4. The MAO coatings coated under the proper condition on AZ91D Mg alloy motorcycle parts provided the far batter corrosion resistance than the substrate, suggesting that MAO coatings can effectively protect the motorcycle parts against the erosion from corrosion medium. Meanwhile, it also found that the irregular part shape has some influence on the coatings formation as well as corrosion resistance.

Deposition time effects on structure and corrosion resistance of duplex MAO/Al coatings on AZ31B Mg alloy

2017 ◽  
Vol 64 (4) ◽  
pp. 357-364 ◽  
Author(s):  
Xue-Jun Cui ◽  
Ying-Jun Zhang ◽  
Bao-Jie Dou ◽  
Xian-Guang Zeng ◽  
Xiu-Zhou Lin
Keyword(s):  
Corrosion Resistance ◽  
Deposition Time ◽  
Mg Alloy ◽  
Structural Defects ◽  
Corrosion Properties ◽  
Corrosive Media ◽  
Combined Process ◽  
Content Type ◽  
Interfacial Compatibility ◽  
Micro Arc Oxidation

Purpose This paper aims to investigate the effects of deposition time on the structure and anti-corrosion properties of a micro-arc oxidation (MAO)/Al coating on AZ31B Mg alloy. Design/methodology/approach The study describes the fabrication of the coating via a combined process of MAO with multi-arc ion plating. The structure, composition and corrosion resistance of the coatings were evaluated using scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction and electrochemical methods. Findings The Al-layer is tightly deposited with a good mechanical interlock along the rough interface due to the Al diffusion. However, the Al layer reduces the anti-corrosion of MAO-coated Mg alloy because of structural defects such as droplets and cavities, which act as channels for corrosive media infiltration towards the substrate. Fortunately, the Al layer improves the substrate corrosion resistance owing to its passive behaviour, and the corrosion resistance can be enhanced with increasing deposition time. All results indicate that a buffer layer fabricated through the duplex process improves the interfacial compatibility between the hard coating and soft Mg alloys. Originality/value An MAO/Al duplex coating was fabricated via a combined process of MAO and physical vapour deposition. MAO/Al duplex coatings exhibit obviously passive behaviours on AZ31 Mg alloy. The structure and corrosion resistance of MAO/Al coatings were investigated.

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