Surface characterisation of cerium layers on galvanised steel

The present paper investigates the inhibition mechanisms of CeCl3·7H2O in a range of concentrations, 100–1000 ppm, on hot dip galvanised steel in 3.5 wt.% NaCl solution. Following 4 h immersion in the studied solution, galvanised steel develops a yellow layer on the surface. X-ray photoelectron spectroscopy (XPS) revealed that the layer is composed of two regions: a surface region, which is a mixture of a hydrated oxide/hydroxide of cerium (III) and ZnO, and an internal region, which is a mixture of ZnO and cerium (III) oxide.