[Back]

I. Bespalov, M. Datler, S. Buhr, J. Zeininger, P. Blaha, G. Rupprechter, Y. Suchorski:
"Initial surface oxidation of Zr: XPS, PEEM, FIM, FEM and DFT studies";
Poster: ECOSS-31 31st European Conference on Surface Science, Barcelona; 08-31-2015 - 09-04-2015; in: "Book of Abstracts", (2015), 412.

Zr and Zr-alloys are widely used in nuclear technology, as e.g. cladding of fuel rods in nuclear reactors [1, 2]. The properties of the thin oxide films usually formed on the Zr surface under operating conditions are thus important for the technological applications. Therefore, the initial stage of zirconium oxidation is extensively studied over decades using various surface analysis techniques. Mostly the composition, the structure and the oxidation state are studied and much less the kinetics and the mechanism of the oxide formation [2, 3]. However, the Zr hcp-to-bcc phase transformation occurring at temperatures usual in nuclear reactors remains mainly disregarded in the Zr oxidation studies. In addition, the knowledge about the role of Zr-suboxides remains still scarce and controversial. In the present contribution we present µm- to nm-scale studies of initial stages of the zirconium oxide formation using XPS, PEEM, FIM, and FEM. Corresponding DFT calculations are in accord with the experimental findings which include the formation of Zr-suboxides. The hcp-to-bcc" phase transformation in Zr is visualized by PEEM for the first time and the role of the resulting structure and surface morphology changes in the ZrOx formation as well as the role of Zr suboxides in the Zr-based oxidic supports of catalytically active noble metals are discussed.

[1] Corrosion of Zirconium Alloys in Nuclear Power Plants, International Atomic Energy Agency, TECDOC-684, 1993 [2] N. Stojilovic, E.T. Bender, R.D. Ramsier, Prog. Surf. Sci. 78 (2005) 101, and references therein. [3] G. Bakradze, L.P.H. Jeurgens, E.J. Mittemeijer, J. Appl. Phys. 110 (2011) 24904