Chemical conversion coating on AZ31B magnesium alloy and its corrosion tendency
来源期刊：Acta Metallurgica Sinica2009年第1期
论文作者：Hualan JIN Ming WANG Xiangjie YANG
Key words：Magnesium alloy; Phosphate; Chemical conversion coating; Corrosion resistance;
Abstract: The morphology change of the magnesium matrix after pre-treatment and the mor-phology as well as the phase composition of chemical conversion coating formed by phosphate were studied using scanning electron microscope and X-ray diffraction. The corrosion resistance of the coating was studied by salt spray and damp test, and the corrosion tendency during salt immersion test was analyzed. The results show that the phase composition before and after pre-treatment is almost change- less, and the deep microflaw appears between α and β phases during acidic pickling. The phosphate conversion coating is mainly composed of Mg, MgO, and some amor-phous phase, and it can provide a good protection for the AZ31B alloy. Results from corrosive morphology indicate that the growth and the corrosion resistance of the phosphate conversion coating are related to the forming process of the AZ31B matrix.
Hualan JIN1，Ming WANG2，Xiangjie YANG2
(1.School of Materials Science and Engineering,Nanchang University,Nanchang 330031,China;
2.School of Mechanical and Electronic Engineering,Nanchang University,Nanchang 330031,China)
Abstract:The morphology change of the magnesium matrix after pre-treatment and the mor-phology as well as the phase composition of chemical conversion coating formed by phosphate were studied using scanning electron microscope and X-ray diffraction. The corrosion resistance of the coating was studied by salt spray and damp test, and the corrosion tendency during salt immersion test was analyzed. The results show that the phase composition before and after pre-treatment is almost change- less, and the deep microflaw appears between α and β phases during acidic pickling. The phosphate conversion coating is mainly composed of Mg, MgO, and some amor-phous phase, and it can provide a good protection for the AZ31B alloy. Results from corrosive morphology indicate that the growth and the corrosion resistance of the phosphate conversion coating are related to the forming process of the AZ31B matrix.
Key words:Magnesium alloy; Phosphate; Chemical conversion coating; Corrosion resistance;
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