Corrosion Science and Technology

The Corrosion Science Society of Korea (한국부식방식학회)
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Mechanical Properties and Corrosion Resistance of Plasma Electrolytic Oxidation Coatings on AZ31 Magnesium Alloy

  • Park, Jae Seon (School of Materials Science and Engineering, Seoul National University) ;
  • Jung, Hwa Chul (School of Materials Science and Engineering, Seoul National University) ;
  • Shin, Kwang Seon (School of Materials Science and Engineering, Seoul National University)
  • Published : 2006.04.01
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Abstract

The plasma electrolytic oxidation (PEO) process is a relatively new surface treatment technique that produces a chemically stable and environment-friendly electrolytic coating that can be applied to all types of magnesium alloys. In this study, the characteristics of oxide film were examined after coating the extruded AZ31 alloy through the PEO process. Hard ceramic coatings were obtained on the AZ31 alloy by changing the coating time from 10min to 60min. The morphologies of the surface and the cross-section of the PEO coatings were examined by scanning electron microscopy and optical microscopy, and the thickness of the coating was measured. The X-ray diffraction pattern of the coating shows that the coated layer consists mainly of the MgO and $Mg_2SiO_4$ phases after the oxidation reaction. The hardness of the coated AZ31 alloy increased with increasing coating time. In addition, the corrosion rates of the coated and uncoated AZ31 alloys were examined by salt spray tests according to ASTM B 117 and the results show that the corrosion resistance of the coated AZ31 alloy was superior to that of the un-coated AZ31 alloy.

Keywords

References

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