Amorphous Al-Mn coating on NdFeB magnets: Electrodeposition from AlCl₃-EMIC-MnCl₂ ionic liquid and its corrosion behavior

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• 作者：Jing Chen ; Bajin Xu ; Guoping Ling ; ^{linggp@zju.edu.cn}
• 关键词：NdFeB ; Al&ndash ; Mn amorphous coating ; Electrolytic etching ; Anodic coating
• 刊名：Materials Chemistry and Physics
• 出版年：2012
• 期刊代码：58_02540584
• 类别：ms
• 出版时间：15 June, 2012
• 卷：134
• 期：2-3
• 页码：1067-1071
• 文件大小：1082 K

摘要

Amorphous Al-Mn coating was electrodeposited on NdFeB magnets from AlCl₃-EMIC-MnCl₂ ionic liquid with the pretreatment of anodic electrolytic etching in AlCl₃-EMIC ionic liquid at room temperature. The microstructure, composition and phase constituents of the coatings were investigated by scanning electron microscopy (SEM), energy-dispersive X-ray spectrometry (EDS), X-ray diffraction (XRD) and transmission electron microscopy (TEM). The corrosion resistance of the coatings was tested by means of potentiodynamic polarization and immersion test in 3.5聽wt.%NaCl solution. The results show that anodic electrolytic etching in AlCl₃-EMIC ionic liquid is a satisfactory pretreatment to remove the surface oxide film and favor the adhesion of the Al-Mn alloy coating to the NdFeB substrate. The amorphous Al-Mn alloy coating provides sacrificial anodic protection for NdFeB. It exhibited good corrosion resistance and signi铿乧antly reduced the corrosion current density of NdFeB by three orders of magnitude at potentiodynamic polarization.