Effect of hydrogen content on hydrogen desorption kinetics of titanium hydride

Thermal desorption behaviours of titanium hydride powders with different hydrogen contents were studied using simultaneous TG-TDS measurements at a heating rate of 10 °C/min. The as-received TiH2 powders were pre-heated to different temperatures and subsequently cooled to room temperature in argon. The XPS depth profile analysis demonstrated that after heat treatments, the relative oxygen concentrations decreased slightly compared with that of as-received TiH2 powder. The changes in the TDS spectra for the pre-heat treated TiH2 powders were primarily associated with the residual hydrogen contents. The origins of the observed TDS peaks and shoulders were attributed to the equilibrium hydrogen pressures of the phase regions that the decomposition reaction passed through. The hydrogen content was demonstrated to be essential for the phase transformation sequence during titanium hydride decomposition.