Surface reactivity of Zr–V–Fe getter alloys exposed to H2O, CO, and O2 at 300 and 700 K

Abstract

The surface analysis of Zr–V–Fe getter alloys by means of x-ray photoelectron spectroscopy shows that the H2O and CO dissociation to form metal oxides and carbides is less important than the O2 dissociation at 300 K. These results are well correlated with theoretical and experimental dissociation energies for the molecules on metal surfaces. A thin passivated layer formed on the metal surface after 1 L CO exposure prevents further CO molecules from dissociating, but O2 dissociation continues. Heating the Zr–V–Fe getter up to 700 K yields an increase of H2O and CO dissociation. The metal surface is less oxidized after O2 exposure at 700 K than at 300 K because oxygen atoms diffuse from the surface into the bulk.