“…The spectra of Ti 0 or TiH 2 disappears at 453.5 eV, while Ti 2þ , Ti 3þ and Ti 4þ exist in the pre-oxidized TiH 2 powders heated at 300 C for 1 h. Compared with the spectra of Ti 2p from the untreated powders, the peak intensity and area of Ti 3þ decrease obviously, and the peak of Ti 2þ appears clearly at about 454 eV. However, there only exhibits the spectra of Ti 4þ in the pre-oxidized TiH 2 powders heated at 500 C for 1 h [22,26]. The oxidizing model may be reasonably presented in Fig.…”