Composite coatings prepared by combined plasma electrolytic oxidation and chemical conversion routes on magnesium-lithium alloy

JOURNAL OF ALLOYS AND COMPOUNDS

卷:706

Article

Li, Zhijun³  Yuan, Yi¹  Jing, Xiaoyan² 

[1] Zhejiang Univ, Dept Chem, Hangzhou 310028, Zhejiang, Peoples R China

[2] Harbin Engn Univ, Coll Mat Sci & Chem Engn, Key Lab Superlight Mat & Surface Technol, Harbin 150001, Peoples R China

[3] Queens Univ, Dept Chem, Kingston, ON K7L 3N6, Canada

关键词: Magnesium-lithium alloy;    Composite coating;    Plasma electrolytic oxidation;    Chemical conversion;    Corrosion resistance;    Electrochemical impedance spectroscopy;   

DOI  :  10.1016/j.jallcom.2017.02.248

来源: Elsevier

【 摘 要 】

Various strategies for the elimination of inherent defects from plasma electrolytic oxidation (PEO) coatings are being developed for practical applications. In this regard, two types of composite coatings were introduced via PEO treatment followed by chemical conversion approach on a magnesium-lithium alloy (Mg-Li alloy). Detailed morphologies and compositions of the composite coatings were studied by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), and thin-film X-ray diffraction (TF-XRD). Barrier properties of the composite coatings were evaluated by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The results demonstrate that this two-step approach improves the anti-corrosion performance of the composite coatings for protection of the Mg-Li alloy. Specifically, the stannate composite coating exhibits enhanced corrosion resistance and impressive long-term stability relative to the composite coating prepared in cerium and lanthanum conversion solution. Our method allows the simple, efficient, and cost-effective fabrication of high-quality composite coatings based on a combined PEO and chemical conversion process on Mg-Li alloys, and therefore it holds great promise for a wide range of applications where corrosion resistance is vital. (C) 2017 Elsevier B.V. All rights reserved.

【 授权许可】

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