A zinc-doped coating prepared on the magnesium alloy by plasma electrolytic oxidation for corrosion protection

Yang, Chao ¹Cai, Hu ¹Cui, Suihan ¹Huang, Jian ¹Zhu, Jiayu ¹Wu, Zhongcan ¹Ma, Zhengyong ¹Fu, Ricky K. Y. ²Sheng, Liyuan ¹Tian, Xiubo ²Chu, Paul K. ¹Wu, Zhongzhen

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作者信息

1. Peking Univ
2. City Univ Hong Kong
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Abstract

Corrosion protection of magnesium alloys is a challenge in industrial applications because of the high chemical reactivity of Mg. In this work, a coating is prepared by plasma electrolytic oxidation (PEO) on the AZ31B Mg alloy and then modified by insoluble zinc phosphate to improve the corrosion resistance. To avoid the influence of the weak acidic Zn-containing electrolyte on the formation of the passivation layer on the magnesium alloy, a two-step process is designed to first produce a passivation layer before introduction of zinc phosphate. Zinc phosphate is mainly distributed on the surface and the sidewalls of the holes in the porous coating and blocks the interactions between the corrosive solution and Mg substrate. The corrosion potential of the optimal coating (Zn-15) increase while the passive current density at the terminal potential decreases, suggesting the significantly improved corrosion resistance compared to the pristine AZ31B. The life time demonstrated by neutral salt spraying is 4200 h that is about 3 times longer than that observed from the Mg alloy with the undoped coating.

Key words

Magnesium alloy/Plasma electrolytic oxidation (PEO)/Zinc phosphate/Corrosion resistance/MICRO-ARC OXIDATION/MG ALLOY/ELECTROCHEMICAL-BEHAVIOR/KOH CONCENTRATION/PEO COATINGS/RESISTANCE/LAYER/SURFACE/FILM

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出版年

2022

Surface & Coatings Technology

ISTP

ISSN：0257-8972

被引量11

参考文献量48

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