抄録
The oxidation processes on a TiAl surface induced by a hyperthermal O2 molecular beam (HOMB) with a translational energy of 2.2 eV was studied by X-ray photoemission spectroscopy in conjunction with synchrotron radiation. At a surface temperature of 300 K, the simultaneous growth of Al and Ti oxides accompanied with the segregation of Al2O3 near the surface was observed. The efficiency of oxidation for the HOMB incidence was smaller than that for O2 backfilling (25 meV). Furthermore, the chemical compositions of oxide species (Al2O3, Ti2O3, TiO2) on the TiAl surface were independent of the translational energy of incident O2 molecule. The present results suggest that the oxidation on TiAl surface proceed via precursor molecular states.
