Formation and characterization of cerium conversion coatings on magnesium alloy

被引：54

作者：

Li Lingjie ^{[1
,2
]}

Lei Jinglei ^{[1
]}

Yu Shenghai ^{[1
]}

Tian Yujing ^{[1
]}

Jiang Qiquan ^{[1
]}

Pan Fusheng ^{[2
]}

机构：

[1] Chongqing Univ, Coll Chem & Chem Engn, Chongqing 400044, Peoples R China

[2] Chongqing Univ, Coll Mat Sci & Engn, Chongqing 400044, Peoples R China

来源：

JOURNAL OF RARE EARTHS | 2008年 / 26卷 / 03期

基金：

中国国家自然科学基金;

关键词：

magnesium alloy; cerium conversion coating; composition; morphology; formation kinetics; rare earths;

D O I：

10.1016/S1002-0721(08)60101-5

中图分类号：

O69 [应用化学];

学科分类号：

081704 [应用化学];

摘要：

Chemical conversion treatment by rare earth metal salt solution was considered as an alternative to chromium chemical conversion treatment to improve the corrosion resistance of magnesium alloys. In this study, cerium conversion coatings formed on AZ31 magnesium alloy were characterized and the formation mechanism was discussed. X-ray photoelectron spectroscopy (XPS) analysis showed that cerium conversion coating consisted of cerium hydroxides/oxides, in which both tetravalent cerium Ce(IV) and trivalent cerium Ce(III) species co-existed. Cerium conversion coating was a two-layer structure. Atomic force microscopy (AFM) images revealed that the morphology of the inside layer was different from that of the outside one, which was responsible for the inherent adhesive weakness of the coating. Corrosion potential (E-corr) measurements indicated that poor adhesion limited the improvement of the corrosion resistance of the coating. During the treating process, the increased pH value of the cerium salt solution led to the precipitation of cerium hydroxides/oxides. The formation kinetics of the coating followed a parabolic curve.

引用

页码：383 / 387

页数：5

共 14 条

[1]

Ardelean H, 2001, MATER CORROS, V52, P889, DOI 10.1002/1521-4176(200112)52:12<889::AID-MACO889>3.0.CO

[2]

2-0

[3]

Kinetic and mechanistic studies of rare earth-rich protective film formation using in situ ellipsometry [J].