Nanoscale analysis of surface oxides on ZnMgAl hot-dip-coated steel sheets.

Arndt, M.; Duchoslav, J.; Itani, H.; Hesser, G.; Riener, C.; Angeli, G.; Preis, K.; Stifter, D.; Hingerl, K.

In this work, the first few nanometres of the surface of ZnMgAl hot-dip-galvanised steel sheets were analysed by scanning Auger electron spectroscopy, angle-resolved X-ray photoelectron spectroscopy and atomic force microscopy. Although the ZnMgAl coating itself is exhibiting a complex micro-structure composed of several different phases, it is shown that the topmost surface is covered by a smooth, homogeneous oxide layer consisting of a mixture of magnesium oxide and aluminium oxide, exhibiting a higher amount of magnesium than aluminium and a total film thickness of 4.5 to 5 nm. Especially by the combined analytical approach of surface-sensitive methods, it is directly demonstrated for the first time that within surface imprints-created by industrial skin rolling of the steel sheet which ensures a smooth surface appearance as well as reduced yield-point phenomenon-the original, smooth oxide layer is partly removed and that a layer of native oxides, exactly corresponding to the chemical structure of the underlying metal phases, is formed. [Figure not available: see fulltext.]

GALVANIZED steel; ELECTRON spectroscopy; PHOTOELECTRON spectroscopy; ATOMIC force microscopy; MAGNESIUM oxide; ALUMINUM oxide

Analytical & Bioanalytical Chemistry, 2012, Vol 404, Issue 2, p651

1618-2642

Academic Journal

10.1007/s00216-011-5507-0