An Auger and XPS survey of cerium active corrosion protection for AA2024-T3 aluminum alloy

The role of cerium inhibitor via the study of the conversion coating (CC) composition by a dual X-Ray pho-to electron (XPS)/Auger spectroscopies analysis. For a convenient protective process used in the industry, such a conversion was reviewed. The material studied was AA 2024-T3 aluminum alloy composed by (in wt%) 3.8-5.0 Cu, 0.2-1.2 Mg, 0.4-1.0 Mn, 0.5-1.2 Si, < than;0.7 Fe, < than;0.1 Cr. Each sample surface was cleaned and prepared using several steps. The samples were finally washed in ethanol and dried in air. Cerium based conversion coatings (CeCC) were deposited at roomtemperature by immersion of the alloy panel in a water solution containing Ce(NO 3 )3,6H 2 O at a different cerium concentrations. Once immersed during 300 s, samples were rinsed four times with deionized water and dried at room temperature in a desiccators. Corrosion attack was conducted on the samples in a 3.5 wt.% NaCl solution at 25°C. The Auger analyses were carried out with the previous JEOLJAMP 9500F Auger spectrometer working under UHV conditions. XPS analysis for the coated panels has shown well-identified chemical entities from the coating but also from the AA2024substrate. Different areas of analysis were pointed out and no difference was found for the chemical composition of the CeCC coating traducing a good homogeneity.