Effect of Impulse Voltage on Microstructure and Corrosion Resistance of Microarc Oxidation Coatings on AZ80 Magnesium Alloy

Abstract:

Microarc oxidation coating and microarc oxidation-fluorocarbon coating were prepared on the surface of AZ80 magnesium alloy profiles. The phase structure, surface morphology and corrosion resistance of the coatings were investigated using SEM, XRD, copper sulfate spot test and polarization curve test. The main phase compositions of the microarc oxidation coatings were MgO, Mg₂SiO₄, MgSiO₃, MgF₂ and MgAl₂O₄. With increasing pulse voltage, the oxidation coating became thicker and the microstructure of the coating surface became compact; therefore the coating corrosion resistance was improved. The oxidation coating with pulse voltage of microarc oxidation controlled between 300-438V obtained the best corrosion resistance. The corrosion current density of magnesium alloy reduced 1-3 orders of magnitude after microarc oxidation treatment with increasing pulse voltage, and the corrosion resistance of microarc oxidation-fluorocarbon coating is desirable.

• Periodical: Key Engineering Materials (Volumes 575-576)
• Pages: 418-422
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.575-576.418
• Online since: September 2013
• Authors: Jie Ma, Yuan Sheng Yang, Xiu Chun Wang, Jing Zhang, Shuo Liu, Xi Bin Yi
• Keywords: Corrosion Resistance, Impulse Voltage, Magnesium Alloy, Micro-Arc Oxidation, Microstructure

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