Water dissociation and selective absorption in the Zr[V 0.5 Fe 0.5 ] 2 gettering alloy: An x-ray photoemission spectroscopy investigation

We report a study, based on x-ray photoemission spectroscopy, on the effects of element-specific selective absorption of the nonevaporable [ Zr(V 0.5 Fe 0.5 ) 2 ] gettering alloy after massive exposure to water vapor (3×10 3 Pa for ≈2000 h at 400 °C). The specimens have been analyzed both after scraping and along a prolonged Ar + sputtering in order to comparatively discriminate intergranular versus intragranular properties. Oxygen is found to diffuse into the bulk of the alloy grains giving a distribution of Zr oxides where ZrO 2 is the major component. After removal of the outermost atomic layers, Fe and V show a major metallic character in the alloy volume. Traces of Zr hydroxides are also seen. The virgin (nonwater treated) [ Zr(V 0.5 Fe 0.5 ) 2 ] alloy has also been comparatively measured.