Cailiao Baohu (Oct 2022)

Effect of Rare Earth Y2O3 on the Microstructure and Properties of AZ31B Magnesium Alloy Coatings Prepared by Micro - Arc Oxidation

  • LI Xin, ZHANG Shenghao, WANG Ziheng, GUO Yupeng, LU Xiaofeng

DOI
https://doi.org/10.16577/j.issn.1001-1560.2022.0273
Journal volume & issue
Vol. 55, no. 10
pp. 37 – 42

Abstract

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Aiming at improving the corrosion resistance of magnesium alloy surface,rare earth Y2O3/MgO ceramic coatings were prepared on AZ31B magnesium alloy via micro-arc oxidation.The hardness and corrosion resistance of the substrate increased.The addition of nano Y2O3 raised the conductivity of the electrolyte,and the voltage at the same treatment time increased.The scanning electron microscopy (SEM) results showed that,the number of “crater”holes,the diameter of micro pores and the porosity decreased with the increase of Y2O3 concentration.X-ray diffraction results indicated that the coatings were mainly consisted of MgO and Y2O3,and the Y2O3 content in the coatings increased with the increase of Y2O3 concentration in electrolyte.Moreover,as the Y2O3 concentration increased from 0 g/L to 4 g/L,the surface roughness of the coating declined from 1.85 μm to 1.48 μm,and the thickness was improved from 52.33 μm to 58.37 μm.When the Y2O3 concentration was 3 g/L,the surface hardness of the as-obtained coating increased to 365.6 HV4.9 N,and the corrosion current decreased to 2.872×10-3 A.

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