Preparation and Corrosion Resistance of Rare Earth Conversion Coatings on AZ91 Magnesium Alloy
来源期刊：JOURNAL OF RARE EARTHS2005年第5期
论文作者：Chen Xiang Li Yingjie Lü Zushun Xu Yue
Key words：metal materials; magnesium alloy; rare earth conversion coatings; corrosion resistance; rare earths;
Abstract: The feasibility of forming pollution-free and environmentally benign Ce-based rare earth conversion coatings (short for RECCs) on AZ91 magnesium alloy to enhance corrosion resistance was studied. The effect of optimum processing parameters on corrosion resistance of RECCs, such as density of treating solution, temperature and time of coating formation were discussed. Protective performance of conversion coatings on magnesium alloy was evaluated by moisture/heating test, anodic polarization, etc. The results show that Ce-based RECCs under moisture/heating condition can remain intact, with high coverage and no obvious corrosion phenomenon. Corrosion potential increases and passive phenomenon occurs while current density decreases, therefore Ce-based RECCs can improve corrosion resistance of AZ91 magnesium alloy. The morphology of Ce-based RECCs prepared under optimum process through SEM observation is found to be a few particles coherent to the base coating, and the coating has no cracks and exhibits apparent corrosion resistance during corrosion courses of AZ91 magnesium alloy.
Chen Xiang1，Li Yingjie2，Lü Zushun3，Xu Yue2
(1.Greater China Regional Technology Center, Colgate-Palmolive Co. Ltd., Guangzhou 510730, China;
2.School of Materials Science and Engineering, Beijing University of Aeronautics and Astronautics, Beijing 100083, China;
3.Department of Applied Chemistry, Harbin Institute of Technology, Harbin 150001, China)
Abstract:The feasibility of forming pollution-free and environmentally benign Ce-based rare earth conversion coatings (short for RECCs) on AZ91 magnesium alloy to enhance corrosion resistance was studied. The effect of optimum processing parameters on corrosion resistance of RECCs, such as density of treating solution, temperature and time of coating formation were discussed. Protective performance of conversion coatings on magnesium alloy was evaluated by moisture/heating test, anodic polarization, etc. The results show that Ce-based RECCs under moisture/heating condition can remain intact, with high coverage and no obvious corrosion phenomenon. Corrosion potential increases and passive phenomenon occurs while current density decreases, therefore Ce-based RECCs can improve corrosion resistance of AZ91 magnesium alloy. The morphology of Ce-based RECCs prepared under optimum process through SEM observation is found to be a few particles coherent to the base coating, and the coating has no cracks and exhibits apparent corrosion resistance during corrosion courses of AZ91 magnesium alloy.
Key words:metal materials; magnesium alloy; rare earth conversion coatings; corrosion resistance; rare earths;
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