Improvement of Corrosion Resistance of Rare Earth Element (REE)-Based Anodic Oxidation Coating on AZ91D Magnesium Alloy

2012 ◽  
Vol 187 ◽  
pp. 210-214 ◽  
Author(s):  
M.Z.M. Zain ◽  
S. Illias ◽  
M. Mat Salleh ◽  
K. Azwan Ismail ◽  
Z. Nooraizedfiza
Keyword(s):  
Corrosion Resistance ◽  
Rare Earth ◽  
Magnesium Alloy ◽  
Anodic Oxidation ◽  
Earth Metal ◽  
Immersion Test ◽  
Corrosion Property ◽  
Anodic Film ◽  
Anodic Films ◽  
Az91d Magnesium Alloy

Anodization is a useful technique for forming protective films on magnesium alloys and improves its corrosion resistance. Based on the rare earth metal (REE) salt solution, the optimum parameter was selected by comparing the anti-corrosion property of anodic film. The structure, component and surface morphology of anodic film and cross-section were analyzed using X-ray diffraction (XRD) and scanning electron microscopy (SEM) coupled with Energy Dispersive Spectroscopy (EDS). The corrosion behavior was evaluated by immersion test. In this paper, a dense anodic film approximately 20 µm thick was prepared on a AZ91D magnesium alloy through anodic oxidation coating. The results show that the anodic films were mainly composed of Mg17Al12, Mg17La2, MgO and amorphous compounds. The best corrosion resistance was obtained with specimen anodized in solution containing both lanthanum nitrate and magnesium, whose corrosion resistance is approximately 3 times higher than that of as-received AZ91D magnesium alloy.

Effects of Lanthanum and Cerium Mixed Rare Earth Metal on Abrasion and Corrosion Resistance of AM60 Magnesium Alloy

2015 ◽  
Vol 44 (3) ◽  
pp. 521-526 ◽  
Author(s):  
Liang Chenghao ◽  
Wang Shusen ◽  
Huang Naibao ◽  
Zhang Zhihong ◽  
Zhang Shuchun ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Rare Earth ◽  
Magnesium Alloy ◽  
Rare Earth Metal ◽  
Earth Metal

Laser Cladding of Zr55Al10Ni5Cu30/SiC Amorphous Composite Coatings on AZ91D Magnesium Alloy for Improvement of Corrosion Resistance

2011 ◽  
Vol 179-180 ◽  
pp. 757-761 ◽  
Author(s):  
Kai Jin Huang ◽  
Hou Guang Liu ◽  
Chang Rong Zhou
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Laser Cladding ◽  
Composite Coatings ◽  
Corrosion Property ◽  
Nacl Solution ◽  
X Ray Diffraction ◽  
X Ray ◽  
Good Corrosion Resistance ◽  
Az91d Magnesium Alloy

To improve the corrosion property of magnesium alloys, Zr-based amorphous composite coatings have been fabricated on AZ91D magnesium alloy by laser cladding using mixed powders Zr55Al10Ni5Cu30/SiC. The microstructure of the coating was characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The corrosion resistance of the coatings was tested in 3.5wt.% NaCl solution. The results show that the coatings mainly consist of amorphous and different crystalline phases. The coatings compared with AZ91D magnesium alloy exhibit good corrosion resistance because of the presence of the amorphous phase in the coatings.

Effect of α-Al2O3 Nano-Additives on Properties of Anodic Oxide Films on AZ91D Magnesium Alloy

2010 ◽  
Vol 148-149 ◽  
pp. 1003-1006
Author(s):  
Xiao Chun Ma ◽  
Tao Li ◽  
Yu Ping Ni
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Oxide Films ◽  
Anodic Oxide ◽  
Immersion Test ◽  
Anodic Films ◽  
Anodic Oxide Films ◽  
Corrosion Resistance Property ◽  
Nano Additives ◽  
Α Al2o3

The effect of α-Al2O3 nano-additives on anodic oxide film-forming and film performance was studied. The morphology and phase compositions of the anodic oxide films were analyzed by scanning electronic microscope (SEM) and X-ray diffraction (XRD). The corrosion resistance of the anodic films with nano-Al2O3 was investigated by immersion test and potentiodynamic polarization technique. The results show that anodic oxide films mainly consists of Mg, Al12Mg17, γ-Al2O3, a little of Si and α-Al2O3. The corrosion resistance property of magnesium alloy can be improved with the addition of α-Al2O3 nano-additives.

Laser Cladding of Mg65Cu25Y10/SiC Amorphous Composite Coatings on AZ91D Magnesium Alloy for Improvement of Corrosion Resistance

2010 ◽  
Vol 143-144 ◽  
pp. 758-762
Author(s):  
Kai Jin Huang ◽  
Hou Guang Liu ◽  
Chang Rong Zhou
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Laser Cladding ◽  
Composite Coatings ◽  
Corrosion Property ◽  
Nacl Solution ◽  
X Ray Diffraction ◽  
X Ray ◽  
Good Corrosion Resistance ◽  
Az91d Magnesium Alloy

To improve the corrosion property of magnesium alloys, Mg-based amorphous composite coatings have been fabricated on AZ91D magnesium alloy by laser cladding using mixed powders Mg65Cu25Y10/SiC. The microstructure of the coating was characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The corrosion resistance of the coatings was tested in 3.5wt.% NaCl solution. The results show that the coatings mainly consist of amorphous and different crystalline phases. The coatings compared to AZ91D magnesium alloy exhibit good corrosion resistance because of the presence of the amorphous phase in the coatings.

Effect of NaVO3 Concentration on Corrosion Resistance of Conversion Coating on AZ91D Magnesium Alloy

2012 ◽  
Vol 576 ◽  
pp. 438-441 ◽  
Author(s):  
N.F.W.M. Sidik ◽  
M.Z.M. Zamzuri ◽  
M. Mat Salleh ◽  
Khairul Azwan Ismail
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Oxide Films ◽  
Chemical Conversion ◽  
Immersion Test ◽  
Optical Microscope ◽  
Conversion Coating ◽  
Energy Dispersive Analysis ◽  
Az91d Magnesium Alloy ◽  
Superior Corrosion Resistance

Anticorrosive oxide films were successfully prepared on AZ91D magnesium alloy by chemical conversion coating in La (NO3)3 electrolytes with and without NaVO3. The morphologies and chemical composition were characterized by optical microscope, scanning electron microscope (SEM) and energy dispersive analysis (EDX). The corrosion resistances of the oxide films were evaluated by salt immersion test. The result showed that the oxide film formed in electrolyte with NaVO3 is successful in providing superior corrosion resistance for AZ91D magnesium alloy.

Effect of heat treatment on anodization and electrochemical behavior of AZ91D magnesium alloy

2005 ◽  
Vol 20 (10) ◽  
pp. 2763-2771 ◽  
Author(s):  
Houng-Yu Hsiao ◽  
Wen-Ta Tsai
Keyword(s):  
Heat Treatment ◽  
Magnesium Alloy ◽  
Polarization Resistance ◽  
Solution Heat Treatment ◽  
Electrochemical Impedance ◽  
Cast Alloy ◽  
Anodic Film ◽  
Air Cooling ◽  
Anodic Films ◽  
Az91d Magnesium Alloy

The anodic films formed on AZ91D magnesium alloy after heat treatment were analyzed and their electrochemical properties were investigated. The results showed that the cooling rate had a significant influence on the microstructure evolution of the AZ91D magnesium alloy after solution heat treatment at 440 °C for 20 h in N2 atmosphere. A single-phase microstructure was observed when the alloy was quenched in water after solution heat treatment. However, a duplex structure consisting of both α and β phases was found if the solution-annealed alloy was cooled in air. The differences in microstructure of the heat treated AZ91D magnesium alloy gave rise to a significant change in the property of the anodic film formed in 3 M KOH + 0.21 M Na3PO4 + 0.6 M KF + 0.15 M Al(NO3)3 electrolyte. During the early stage of anodization, for the as-cast alloy, inhomogeneous anodic films were formed exhibiting relative rough surface appearances. A rather smooth anodic film was formed for the solution-annealed AZ91D magnesium alloy either followed by air cooling or water-quenched. The surface and cross section appearance was almost the same regardless of the prior heat treatment after anodizing for 20 min. The corrosion resistances of the various anodized AZ91D magnesium alloy were evaluated and compared by employing electrochemical impedance spectroscopy (EIS). The results demonstrate that the anodic film formed on the water-quenched AZ91D magnesium alloy had a slightly higher polarization resistance than that formed on the as-cast alloy. The highest polarization resistance of anodic film was found for that formed on annealed and air-cooled alloy. The presence of Al-rich β phase on the surface gave rise to the formation of a more protective anodic film which consisted of a great amount of Al2O3.

Effect of combinative addition of strontium and rare earth elements on corrosion resistance of AZ91D magnesium alloy

2008 ◽  
Vol 18 (5) ◽  
pp. 1058-1064 ◽  
Author(s):  
Jie-xin NIU ◽  
Qiu-rong CHEN ◽  
Nai-xin XU ◽  
Zhong-ling WEI
Keyword(s):  
Corrosion Resistance ◽  
Rare Earth ◽  
Magnesium Alloy ◽  
Rare Earth Elements ◽  
Az91d Magnesium Alloy

Characteristic and Corrosion Studies of Rare Earth (REE) Based Anodizing on AZ91D Magnesium Alloy

2013 ◽  
Vol 594-595 ◽  
pp. 571-574
Author(s):  
Mat Akhir Khalid Azadi ◽  
M.Z.M. Zamzuri ◽  
S. Norbahiyah ◽  
Mohd Nazree Derman
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Immersion Test ◽  
Optical Microscope ◽  
Oxide Coatings ◽  
Az91d Magnesium Alloy ◽  
Β Phase ◽  
Corrosion Studies ◽  
Corrosion Behaviors ◽  
Scanning Electron

Oxide coatings on AZ91D magnesium alloy were prepared using anodizing technique with 10mA/cm2 current density for 5 minutes in electrolyte containing Mg (NO3)2 with NaVO3 as an additive. The corrosion behaviors of different coatings condition were evaluated by immersion test in 5.0% NaCl electrolyte for 72 hours. The microstructures were analyzed by Optical Microscope (OM) and Scanning Electron Microscope (SEM). It was found that coatings with the addition of NaVO3 produced homogeneous primary α-matrix and bigger β-phase (Mg17Al12) compared to untreated AZ91D magnesium alloy. The oxide film formed by anodizing in electrolyte with NaVO3 enhances the corrosion resistance of the AZ91D magnesium alloy significantly.

Characteristic and Corrosion Studies of Rare Earth (Ree) Based Anodizing on AZ91D Magnesium Alloy

2014 ◽  
Vol 879 ◽  
pp. 38-42
Author(s):  
Mat Akhir Khalid Azadi ◽  
M.Z.M. Zamzuri ◽  
S. Norbahiyah ◽  
M.R.N. Liyana ◽  
M. Marina ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Immersion Test ◽  
Optical Microscope ◽  
Oxide Coatings ◽  
Az91d Magnesium Alloy ◽  
Β Phase ◽  
Corrosion Studies ◽  
Corrosion Behaviors ◽  
Scanning Electron

Oxide coatings on AZ91D magnesium alloy were prepared using anodizing technique with 10mA/cm2 current density for 5 minutes in electrolyte containing La (NO3) and Mg (NO3),with NaVO3 as an additive. The corrosion behaviors of different coatings condition were evaluated by immersion test in 5.0% NaCl electrolyte for 72 hours. The microstructures were analyzed by Optical Microscope (OM) and Scanning Electron Microscope (SEM). It was found that coatings with the addition of NaVO3 produced homogeneous primary α-matrix and bigger β-phase (Mg17Al12) compared to untreated AZ91D magnesium alloy. The oxide film formed by anodizing in electrolyte with NaVO3 enhances the corrosion resistance of the AZ91D magnesium alloy significantly

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