Corrosion protection of magnesium AZ31 alloy using poly(ether imide) [PEI] coatings prepared by the dip coating method: Influence of solvent and substrate pre-treatment

• DOI: 10.1016/j.corsci.2010.09.040
• Publication Date: 2010-09-19T04:14:03Z
• Authors: Thiago F. da Conc...; N. Scharnagl; W. Dietzel; K.U. Kainer
• Keywords: Hydrofluoric acid; Imide; Acetamide

Abstract In this study, investigations on the protectiveness of poly(ether imide) coatings against corrosion of magnesium AZ31 alloy sheets are performed. The coatings were prepared in different pre-treated substrates by the dip coating method using N′N′-dimethyl acetamide (DMAc) and N′-methyl pyrrolidone solutions. The optimal performance was obtained for hydrofluoric acid treated substrates coated using DMAc solution (coating thickness 13 μm) which showed impedances in the order of 107 Ω cm2 even after more than 3300 h of exposure to a 3.5 wt.% NaCl solution. This high performance is associated to an acid–base interaction at the interface as observed by X-ray photoelectron spectroscopy.