Focus on XPS Investigations of Zn and Zn-alloy Coated Steel Sheets: a Study on Radiation-and Sputter-induced Influences for a Reliable Analysis of Industrial Samples

摘要

X-ray photoelectron spectroscopy (XPS) is a highly qualified analysis technique, mostly claimed to be of non-destructive nature, to study the surface of Zn and Zn-based coatings regarding chemical composition and combined with Ar~+ ion sputtering also chemical gradients over depth. Due to the fact that some chemical compounds, which may form on these coatings initially after production or after corrosion load, reveal an unstable nature their chemical stability was investigated during regular surface measurements and ion bombardment used for acquiring depth profiles. A detailed study led to the information that different materials suffer damage/degradation by different parts of the XPS setup. In this context, especially the excitation source, the charge compensation system and the sputter device should be quoted as potential cause for degradation. On the base of the made findings it is now possible to rate the reliability of measurement results obtained from XPS surface investigations and depth profiles.