Evaluation of the micro-arc oxidation treatment effect on the protective performance of a Mg-rich epoxy coating on AZ91D magnesium alloy

2015 ◽  
Vol 270 ◽  
pp. 227-235 ◽  
Author(s):  
Xiangyu Lu ◽  
Xingguo Feng ◽  
Yu Zuo ◽  
Chuanbo Zheng ◽  
Sheng Lu ◽  
...  
Keyword(s):  
Magnesium Alloy ◽  
Treatment Effect ◽  
Epoxy Coating ◽  
Oxidation Treatment ◽  
Az91d Magnesium Alloy ◽  
Micro Arc Oxidation ◽  
Protective Performance

Microstructure and Properties of MAO Coatings for AZ91D Magnesium Alloy in Varies Work Mode

2013 ◽  
Vol 747-748 ◽  
pp. 178-183 ◽  
Author(s):  
Xue Jun Cui ◽  
Xiu Zhou Lin ◽  
Chun Hai Liu ◽  
Rui Song Yang ◽  
Ming Tian Li
Keyword(s):  
Magnesium Alloy ◽  
Orthogonal Experiment ◽  
Constant Current ◽  
Optimum Process ◽  
Az91d Magnesium Alloy ◽  
Experiment Method ◽  
Micro Arc Oxidation ◽  
Orthogonal Experiment Method ◽  
Power Mode

Micro arc oxidation coatings were prepared on AZ91D magnesium alloy in order to evaluate the role of electrical parameters under different work mode. Taking HV hardness and pit corrosion time as investigation index, the optimum process parameters were obtained through orthogonal experiment method. The morphology of coating was observed by scanning electron microscopy (SEM). The results showed that the coatings with dense and few micro pores can be obtained under constant current and power mode, and this kind coatings are of good corrosion resistance and have HV micro-hardness compared with those under constant voltage mode.

Investigation of the Anti-Corrosion Ceramic Coating Formed on AZ91D Magnesium Alloy by Micro-Arc Oxidation

2007 ◽  
Vol 353-358 ◽  
pp. 1645-1648 ◽  
Author(s):  
Dong Chu Chen ◽  
Wen Fang Li ◽  
Jun Jie
Keyword(s):  
Magnesium Alloy ◽  
Ceramic Coating ◽  
Silicate Solution ◽  
Processing Parameters ◽  
Time Duration ◽  
Compact Structure ◽  
Az91d Magnesium Alloy ◽  
Micro Arc Oxidation ◽  
Coating Formation ◽  
And Performance

A new micro-arc oxidation method with a home-made asymmetric alternating-current (ac) power supply for forming an anti-corrosion ceramic coating on AZ91D magnesium alloy was presented, and two different silicate-based and aluminate-based preparing solutions were introduced to coating formation. The effect of many processing parameters on the growth and performance of the formed ceramic coating was investigated. It was found that the electrolyte concentration, current density, treating time duration and other parameters have significant influence on the coating morphology and anti-corrosion performance. Through the polarization curve test, it showed that the coating oxidized in silicate solution has better corrosion-resistance due to its continuous and compact structure than that formed in aluminate solution. The morphology and microstructure of the coating were analyzed through SEM, XRD technology. The coating consists of two layers, i.e., loose layer and compact layer. The compositions and phase structures varied with electrolytes, and it was found that the micro-arc oxidation coating prepared in silicate solution is composed of MgO and Mg2SiO4, while the coating prepared in aluminate is mainly composed of MgAl2O4.

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