中国有色金属学报(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 24 No. 12 December 2014 |
（1. College of Materials Engineering, Nanjing Institute of Technology, Nanjing 211167, China;
2. Jiangsu Key Laboratory of Advanced Structural Materials and Application Technology, Nanjing 211167, China;
3. Jiangsu Konsung Equipment Co., Ltd., Danyang 212300, China）
Abstract:A new method for synthesizing Mg-Al hydrotalcite conversion coating on AZ91D Mg alloy was developed by the application of electric field (EF). By using EF technique, the formation time of the coating can be significantly reduced. The SEM results indicate that a continuous and compact Mg-Al hydrotalcite coating is formed on the surface of Mg alloy after short time EF treatment. However, a long time treatment would make the coating partially exfoliate. The corrosion current density (Jcorr) of the coated sample (EF1+1 h) is approximately two orders of magnitude lower than that of Mg alloy substrate. The test of electrochemical impedance spectroscopy (EIS) and immersion corrosion also suggest that the coating can effectively protect Mg alloy against corrosion.
Key words: magnesium alloy; Mg-Al hydrotalcite; conversion coating; corrosion resistance; electric field
