Influence of 8-hydroxyquinoline on properties of anodic coatings obtained by micro arc oxidation on AZ91 magnesium alloys

2012 ◽  
Vol 539 ◽  
pp. 249-255 ◽  
Author(s):  
R.F. Zhang ◽  
S.F. Zhang ◽  
N. Yang ◽  
L.J. Yao ◽  
F.X. He ◽  
...  
Keyword(s):  
Magnesium Alloys ◽  
Micro Arc Oxidation ◽  
Az91 Magnesium

Study on the Formation Mechanism of Micro-Arc Oxidation Coatings on Magnesium Alloys

2010 ◽  
Vol 650 ◽  
pp. 228-233 ◽  
Author(s):  
Xian Ming Chen ◽  
Cheng Ping Luo ◽  
Jiang Wen Liu
Keyword(s):  
Magnesium Alloys ◽  
Formation Mechanism ◽  
Cellular Structure ◽  
Az91 Magnesium Alloy ◽  
Transmission Electron ◽  
Micro Arc Oxidation ◽  
Az91 Magnesium ◽  
Ac Current ◽  
Means Of Transmission ◽  
Nano Grains

This article concerned with the formation mechanism of the micro-arc oxidization(MAO) coating on magnesium alloys. The micro-arc oxidation ceramic coating on AZ91 magnesium alloy was prepared in a silicate alkaline solution (Na2SiO3:5-30g/l, NaOH: 1-5g/l, KF: 5-8g/l, Na3C6H5O7: 0.5-2g/l, EDTA: 0.5-2g/l). The experiments were carried out in AC current galvanostatic mode with a current density of 20-50A/dm2. The microstructure of the MAO coating was characterized by means of transmission electron microscopy(TEM). Microcrystallite and/or nanocrystallite were found in the MAO coatings, the size of the former was about 50-200nm and the latter was about 20-50nm. Cellular structure was observed in the coatings, which was composed of a lot of micro/nano grains. The grains grew preferentially in some directions during the MAO process, and the cellular structure is formed by the grains growing in a laminar way. The cellular structures also grew and aggregated by laminar way to form the whole MAO coatings.

Influences of Tannic Acid Concentration on Properties of Micro-Arc Coatings Formed on AZ91 Magnesium Alloys

2012 ◽  
Vol 182-183 ◽  
pp. 297-301
Author(s):  
Shu Fang Zhang ◽  
Rong Fa Zhang ◽  
Tao Wang ◽  
Shun Shun Yao ◽  
Zhi Hua Chen
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloys ◽  
Acid Concentration ◽  
Tannic Acid ◽  
Coating Properties ◽  
Micro Arc Oxidation ◽  
Az91 Magnesium ◽  
Solution Conductivity ◽  
Coating Color

Anodic coatings were prepared by micro-arc oxidation on AZ91 magnesium alloys with the addition of 0-8 g/L tannic acid. The influences of tannic acid concentration on the conductivity and coating properties were studied. The result shows that with the increase of tannic acid concentration, the solution conductivity decreases and the coating color becomes dark. In the solution with 4 g/L tannic acid, the obtained coatings are the most uniform and achieve the best corrosion resistance.

Fatigue behavior of calcium containing AZ91 magnesium alloys

2015 ◽  
Vol 57 (2) ◽  
pp. 126-130
Author(s):  
Dorothea Amberger ◽  
Tina Blickle ◽  
Heinz Werner Höppel ◽  
Mathias Göken
Keyword(s):  
Magnesium Alloys ◽  
Fatigue Behavior ◽  
Az91 Magnesium
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