Non-isothermal kinetics and in situ SR XRD studies of hydrogen desorption from dihydrides of binary Ti-V alloys

Phase transformations during dynamic dehydrogenation of Ti1−xVxH2 (x = 0.1; 0.2; 0.3) were studied using in situ Synchrotron X-Ray Diffraction (SR XRD) and non-isothermal kinetics experiments. The main dehydrogenation path for γ-Ti1−xVxH2 was found to be γ → δ → β → βalloy. Body-centred tetragonal δ-hydride was found to be an intermediate phase of the γ → β transformation in Ti0.8-0.9V0.1-0.2H2. TDS, in situ SR XRD and isoconversional kinetics studies showed that hydrogen desorption from Ti1−xVxH2 is composed of simultaneous reactions taking place between 300 and 600 °C. The effective activation energy of hydrogen desorption depends on the vanadium contents and the reaction pathway, increasing from 21 kJ/mol H2 (γ → δ) to 60-110 kJ/mol H2 (δ → β).