Water dissociation and selective absorption in the Zr[V0.5Fe0.5]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(V0.5Fe0.5)(2)] gettering alloy after massive exposure to water vapor (3 x 10(3) Pa for approximate to 2000 h at 400 degrees 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 ZrO2 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(V0.5Fe0.5)(2)] alloy has also been comparatively measured. (C) 1999 American Vacuum Society. [S0734-2101(99)05402-0].