Characterization of oxidation products on a ZrFe2-type laves intermetallic exposed to 200degreeC steam

The release of radioactive elements from the stainless steel-15 wt% zirconium (SS-15Zr) metal waste form will be governed by the corrosion behavior of ZrFe2-type intermetallics phases present in the alloy. In this article, oxidation products that formed on a ZrFe2-type intermetallic sample exposed to 200 C steam were characterized by Auger Electron Spectroscopy (AES) and Transmission Electron Microscopy (TEM). The data revealed two oxide layers on the sample surface: an outer crystalline iron-oxide layer and an inner amorphous zirconium-rich layer believed to be zirconium oxide. Thermodynamic considerations indicate that the zirconium-rich layer formed first. The iron-oxide layer appears to have resulted from the diffusion of iron through the zirconium-rich layer to the oxide-vapor interface