Near-surface chemistry in Zr2Fe and ZrVFe studied by means of x-ray photoemission spectroscopy: A temperature-dependent study

The near-surface atomic composition and the character of chemical bond in t wo nonevaporable gettering alloys have been investigated via core level (Zr 3d, Fe 2p, V 2p, O Is, C Is) photoemission. The samples have been measured in UHV after in-air fracturing and various annealing steps (up to 850 degr eesC). For T > 400 degreesC a progressive and sizeable decrease of the near surface C content along with an increase in the Zr concentration is observ ed in both alloys. An annealing induced Zr enrichment at the surface is fou nd, the metallic atomic concentrations being significantly far from the nom inal bulk stoichiometry. The annealing induces a strong evolution in the ch emical bonds, the metallic species being completely oxidized in in-air frac tured samples while a metallic character progressively emerges at increasin g temperatures. Surface metallization proceeds faster in Zr2Fe than in the V-containing getter. (C) 2000 American Vacuum Society. [S0734-2101(00)01406 -8].