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An electrochemical impedance study of ionic liquid film formation and aqueous corrosion of magnesium alloy ZE41
journal contributionposted on 01.12.2008, 00:00 authored by Patrick HowlettPatrick Howlett, W Neil, Timothy KhooTimothy Khoo, J Sun, Maria ForsythMaria Forsyth, D MacFarlane
Ionic liquid surface treatments are proposed as a method of controlling corrosion processes on magnesium alloys. An important magnesium alloy, ZE41 (nominally 4% Zn and 1% rare earth), was treated with the ionic liquid trihexyl(tetradecyl)phosphonium diphenylphosphate (P66614DPP). Impedance spectra were acquired at intervals during the treatment, indicating the development of a film and allowing a measure of the film formation process to be obtained over time. Mechanically polished and electro-polished surfaces were prepared; these surfaces, treated and untreated, were subsequently exposed to 0.1 M NaCl aqueous solutions. The corrosion behavior of the prepared surfaces were assessed using impedance spectroscopy and optical microscopy. The results indicated a significant role for the method of surface preparation used and, in both cases, the ionic liquid treatment produced a more corrosion-resistant surface.