Corrosion Behavior of Metallic Materials in Acidic-Functionalized Ionic Liquids

This paper describes the influence of temperature, water content, and anionic type of acidic-functionalized ionic liquids (Ws), 1-(4-sulfobutyl)-3-methylimidazolium hydrogen sulfate ([BsMIM][HSO4]) and 1-(4-sulfobutyl)-3-methylimidazolium toluenesulfonate ([BsMIM][OTs]), on the corrosion behavior of Fe, Ni, and 304 stainless steel (304SS). Electrochemical methods including electrochemical impedance spectroscopy (EIS) and Tafel plots were used to investigate it. Also, scanning electron microscopy (SEM) was used to characterize the nature of the corrosion morphology. The obtained electro-chemical results indicated that increasing temperature accelerates the corrosion, while decreasing IL concentration retards the corrosion. The corrosion process is controlled by charge transfer. Moreover, the bisulfate anion (HSO4-) has an effect on the corrosion rate more significantly than the p-toluenesulfonate anion (OTs-) does. The SEM spectrum showed that the corrosion situation of Fe is more serious than Ni and 304SS performed in IL-based solutions, especially in [BsMINI] [HSO4]. Also, the protective layer formed on the 304SS surface is more uniform. On the basis of these consistent finds, the corrosion mechanism is assumed.