Corrosion behaviors of materials in aluminum chloride–1-ethyl-3-methylimidazolium chloride ionic liquid

Abstract The corrosion properties of carbon steel (CS), 304 stainless steel (304 SS), and pure titanium (Ti) are first studied in aluminum chloride–1-ethyl-3-methylimidazolium chloride ionic liquid (IL). An active-to-passive transition behavior was clearly observed for CS. The 304 SS exhibited the best stability among the materials; no considerable corrosion was recognized even in this high-chloride environment. In contrast, although Ti resists corrosion in ambient environments, it was not passivated in the IL and became severely corroded under an anodic applied potential. The material corrosion behaviors and mechanisms in the non-aqueous, low-oxygen, and high-halogen-containing IL are completely different from those in traditional aqueous solutions.