Characterization and Corrosion Studies of Amorphous/Nanocrystalline Conversion Coatings Formed by Applying Static Magnetic Field on AZ91 D Magnesium Alloy

2011 ◽  
Vol 189-193 ◽  
pp. 805-809 ◽  
Author(s):  
Ming Zhao ◽  
Liang Zhu ◽  
Guang Ping He
Keyword(s):  
Magnetic Field ◽  
Magnesium Alloy ◽  
Static Magnetic Field ◽  
Nanocrystalline Structure ◽  
Amorphous Structure ◽  
Conversion Coating ◽  
Conversion Coatings ◽  
Artificial Defect ◽  
Az91d Magnesium Alloy ◽  
Electrode Technique

The present work explores an environmental friendly method for forming conversion coatings on AZ91D magnesium alloy by applying a static magnetic field. An amorphous / nanocrystalline conversion coating was developed on magnesium alloys in a phosphate-permanganate aqueous solution under a 0.5 Tesla magnetic field. The examinations of the microstructure and phase compositions reveal that the conversion coating is composed of an amorphous structure and nanocrystalline structure with mean size less than 10 nm. In a corrosive chloride solution, the amorphous/nanocrystalline conversion coating with an artificial defect were investigated by scanning vibrating electrode technique (SVET)/ scanning ion-selective electrode technique (SIET) system. The micro-electrochemical results reveal that the amorphous / nanocrystalline conversion coating as a good barrier layer can provide effective corrosion protection for AZ91D magnesium alloy.

EIS Study of Molybdate Conversion Coatings Formed on AZ91D Magnesium Alloy

2011 ◽  
Vol 189-193 ◽  
pp. 279-285
Author(s):  
Li Ping Wu ◽  
Zhong Dong Yang
Keyword(s):  
Corrosion Resistance ◽  
Charge Transfer ◽  
Magnesium Alloy ◽  
Charge Transfer Resistance ◽  
Conversion Coating ◽  
Conversion Coatings ◽  
Bath Composition ◽  
Optimum Conditions ◽  
Transfer Resistance ◽  
Az91d Magnesium Alloy

An environmentally friendly molybdate conversion coating based surface treatment was developed for AZ91D magnesium alloy. The EIS technique was employed to study the effects of the conversion bath composition and temperature on the corrosion protection performance of molybdate conversion coatings on AZ91D magnesium alloys. The optimum conditions under which obtained conversion coatings showed the best corrosion resistance were determined. The Nyquist results showed that the value of charge transfer resistance increased by 22.5 times for the sample treated in the optimized molybdate conversion bath.

Study of the formation and growth of tannic acid based conversion coating on AZ91D magnesium alloy

2009 ◽  
Vol 204 (5) ◽  
pp. 736-747 ◽  
Author(s):  
Xiaoming Chen ◽  
Guangyu Li ◽  
Jianshe Lian ◽  
Qing Jiang
Keyword(s):  
Magnesium Alloy ◽  
Tannic Acid ◽  
Conversion Coating ◽  
Az91d Magnesium Alloy

An organic chromium-free conversion coating on AZ91D magnesium alloy

2008 ◽  
Vol 255 (5) ◽  
pp. 2322-2328 ◽  
Author(s):  
Xiaoming Chen ◽  
Guangyu Li ◽  
Jianshe Lian ◽  
Qing Jiang
Keyword(s):  
Magnesium Alloy ◽  
Conversion Coating ◽  
Az91d Magnesium Alloy

Preparation and characterization of colored Ti/Zr conversion coating on AZ91D magnesium alloy

2015 ◽  
Vol 276 ◽  
pp. 239-247 ◽  
Author(s):  
Aihua Yi ◽  
Jun Du ◽  
Jian Wang ◽  
Songling Mu ◽  
Guoge Zhang ◽  
...  
Keyword(s):  
Magnesium Alloy ◽  
Conversion Coating ◽  
Az91d Magnesium Alloy
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