Corrosion characterization of microarc oxidation coatings formed on Mg-7Li alloy

被引：11

作者：

Li, J. G. ^{[1
,2
]}

Lv, Y. ^{[2
]}

Wang, H. W. ^{[1
]}

Zhu, Z. J. ^{[1
]}

Wei, Z. J. ^{[1
]}

Meng, X. C. ^{[2
]}

机构：

[1] Harbin Inst Technol, Sch Mat Sci & Engn, Harbin 150001, Peoples R China

[2] Jiamusi Univ, Sch Mat Sci & Engn, Jiamusi 154007, Peoples R China

来源：

MATERIALS AND CORROSION-WERKSTOFFE UND KORROSION | 2013年 / 64卷 / 05期

基金：

中国国家自然科学基金;

关键词：

ceramic coatings; corrosion resistance; MgLi alloy; microarc oxidation; MG-LI ALLOY; RESISTANCE;

D O I：

10.1002/maco.201106492

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

Ceramic coatings with thickness of 27 mu m were fabricated on Mg7Li alloy in Na2SiO3C6H18O24P6 solution by microarc oxidation (MAO). The morphology and phase composition of MAO coatings were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The corrosion behavior of the bare and MAO coated Mg7Li alloy was investigated by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). Results showed that the MAO coatings were composed of MgO, Li2O, and Mg2SiO4, and there existed some micropores on the coating surface with a diameter of 320 mu m. The corrosion potential (Ecorr) and corrosion current density (Icorr) of the MAO coated alloy were about 1.4761V and 7.204x107A/cm2, respectively. The Ecorr of the MAO coated alloy increased by 109.6mV and its Icorr decreased by three orders compared with that of the bare Mg7Li alloy. The EIS plots indicated that the impedance of the MAO coated alloy was 15 times higher than that of the bare alloy. The fitting parameters showed that the resistance of the MAO coatings was far greater than that of the bare alloy. The dense intermediate layer and the transition layer of the MAO coatings acted as a barrier to hinder the proceeding of solution permeation, remarkably improving the corrosion resistance of the Mg7Li alloy.

引用

页码：426 / 432

页数：7

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