Oxidation of TiAl surface with hyperthermal oxygen molecular beams

Hashinokuchi, Michihiro*; Tode, Mayumi*; Yoshigoe, Akitaka ; Teraoka, Yuden; Okada, Michio*

Detailed studies on the initial oxidation processes of TiAl with a 2 eV hyperthermal oxygen molecular beam and thermal O in the backfilling. The oxidation processes are monitored by X-ray photoemission spectroscopy measurements in conjunction with synchrotron radiation. Oxidation of both Al and Ti occurs during the oxidation. The incident-energy and surface-temperature dependences of oxidation reveal that the precursor-mediated dissociative adsorption is the dominant initial step in the thermal O backfilling. Thus, the efficiency of oxidation is higher for the thermal O backfilling than for the molecular beam dose. The result is quite different from that on TiNi where the molecular beam dose has the advantages in the oxide layer growth at high O coverage. We succeeded in fabricating blue-colored TiO and AlO containing layers, combining molecular beam and surface annealing.