Abstract:

The anodic behavior of Fe in 2:1 acidic AlCl₃-1-ethyl-3-methyl-imidazolium chloride (AlCl₃-EMIC) ionic liquid was investigated in this paper. Anodic polarization and chronoamperometry was measured using three-electrode system. The valence state of dissolved Fe was calculated by potentiostatic process. The surface morphologies of Fe were characterized using a scanning electron microscopy (SEM). The results showed that the oxide film would restrain the dissolution of Fe. After the oxide film was removed, Fe began to dissolve at the potential of -0.35 V versus Pt. The anodic current density increased rapidly to a maximum with the positive shift of potential and than decreased abruptly. The product existed in the form of Fe(Ⅱ). After galvanostatic process at 2 mA·cm^-2, the surface of Fe showed a pitting morphology, which became homogeneous as time prolonged. With a larger anodic current applied (15 mA·cm^-2), no obvious corrosion occurred on the surface of Fe electrode with precipitate formed.

Key words: Fe, AlCl₃-EMIC ionic liquid, anodic behavior

摘要：

重点研究了纯铁（Fe）在2∶1酸性AlCl₃-氯化1-甲基-3-乙基咪唑（AlCl₃-EMIC）中的阳极行为。通过三电极体系测定了Fe在AlCl₃-EMIC中的阳极极化和不同电位下的电流-时间曲线，利用恒电位溶解计算了Fe溶解的价态，最后通过扫描电子显微镜（SEM）观察了不同电流密度下Fe的溶解形貌。结果表明：Fe表面的氧化膜会阻碍Fe的溶解，在去除氧化膜后，当电位达到-0.35 V时，Fe开始发生活性溶解，产物为Fe（Ⅱ）。Fe的阳极电流密度随电位的增加而增加，达到峰值后显著下降。小电流密度下（如2 mA·cm^-2），Fe的溶解形貌随时间的延长，呈现先点状腐蚀再均匀腐蚀的特点；而大电流密度下（如15 mA·cm^-2），Fe电极表面会生成一层固态物质，同时可见清晰的划痕，即不发生明显的腐蚀。

关键词: Fe, AlCl₃-EMIC离子液体, 阳极行为