Surface characterizations of TiH2 powders before and after dehydrogenation

Abstract

The oxide film of TiH2 and HDH-Ti powder are investigated using X-ray photoelectron spectroscopy (XPS). The XPS depth profiles indicate that there exists mainly Ti2+, Ti3+, Ti4+ and Ti0 on TiH2 and HDH-Ti surface. The intensities of Ti 2p decrease for Ti4+, first increase and then decrease for Ti3+ and Ti2+, and increase all the time for Ti0 in the surface layer of TiH2 and HDH-Ti with the sputtering depth increasing. The relative fractions of TiO2, Ti2O3 and TiO for the Ti 2p of TiH2 and HDH-Ti first decrease and then slow down with the sputtering depth increasing. Meanwhile, the relative fractions of TiO2 and TiO of HDH-Ti are lower than that of TiH2 after the sputtering depth of about 5nm, and the fraction of Ti2O3 of HDH-Ti is always lower that of TiH2. In addition, the decrease of Ti2O3 is much pronounced, followed by TiO2 and TiO before and after dehydrogenation when the sputtering depth is more than 5nm. The XPS depth profiles and calculation results suggest that the release of H atoms removes the part of oxygen on TiH2 surface, which results in the thinner oxide layer and low oxygen content of HDH-Ti powder.