Effect of potassium fluoride in electrolytic solution on the structure and properties of microarc oxidation coatings on magnesium alloy

Stress corrosion cracking (SCC) of a forged Mg-Al-Zn magnesium alloy with different surface conditions was studied by the four-point bending test and alternate immersion test in NaCl solution. The results showed that the bare Mg-Al-Zn magnesium alloy has low susceptivity to SCC, and no abrupt rupture happened after the immersion test for 5 days under an initial stress load of 0.15–0.75σ0.2. With microarc oxidation (MAO) coating, corrosion resistance was enhanced, but more surface cracks were induced, and microcracks could be detected inside corrosive pits when the load was 0.75σ0.2, which is similar to the bare alloy. The composite coating totally avoided both SCC and corrosion. The low susceptivity of the forged AQ80M alloy to SCC should be attributed to the fine grain size and even distribution of secondary phases around the grain boundary.

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Effect of cw-CO2 laser surface treatment on structure and properties of AZ91 magnesium alloy

Optics and Lasers in Engineering ◽

10.1016/j.optlaseng.2016.01.009 ◽

2016 ◽

Vol 81 ◽

pp. 63-69 ◽

Cited By ~ 9

Author(s):

Józef Iwaszko ◽

Monika Strzelecka

Keyword(s):

Magnesium Alloy ◽

Surface Treatment ◽

Co2 Laser ◽

Laser Surface ◽

Structure And Properties ◽

Laser Surface Treatment ◽

Az91 Magnesium Alloy ◽

Az91 Magnesium ◽

Cw Co2 Laser

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Structure and Properties of Anodized Films Formed on AZ91D Magnesium Alloy

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.66-68.1586 ◽

2011 ◽

Vol 66-68 ◽

pp. 1586-1591

Author(s):

Jian San Li ◽

Jun Quan Liu

Keyword(s):

Magnesium Alloy ◽

Current Density ◽

Potentiodynamic Polarization ◽

Solution Structure ◽

Solution Temperature ◽

Anodic Current Density ◽

Polarization Analysis ◽

Structure And Properties ◽

Anodic Current ◽

Az91d Magnesium Alloy

Anodized films on AZ91D magnesium alloy were prepared in sodium hydroxide based solution. Structure and properties of the anodized films were investigated by X-ray diffraction (XRD), scanning electron microscope (SEM) and electrochemical potentiodynamic polarization analysis. The results of XRD showed that the films were mainly composed of Mg(OH)2and Al(OH)3. As the solution temperature increasing, the anodized films became thicker and denser, which could cover up the substrate. The films also became thicker and denser with the increase of anodizing time. The grain in the films grew fast when anodic current density increasing and a larger grain size would be found at a higher anodic current density. The results of microscopic analysis exhibited the porous-type anodic oxide, which was similar to the films on aluminum alloy. The results of electrochemical potentiodynamic polarization analysis showed that thermodynamic stability of the alloy had a certain improvement after anodization. The anodized films also exhibited an obvious increase of polarization resistanceRPand an obvious decrease of corrosion current densityic. Discoloration time of drop test on the films lasted for 30 min, which indicated that corrosion resistance of the magnesium alloy was greatly improved by anodization.

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