The equilibrium between hydrogen isotopes and TiVCr alloys

TiVCr alloys are treated as candidate materials for hydrogen isotope separation because of their prominent inverse isotope effects and hydrogen storage properties. In this work, the relationship between the separation factor (αH-D) that characterizes the isotope effects and the ratio of equilibrium pressures (RP) of the isotopes was investigated. It was found that αH-D in the plateau region was independent on RP of the α-phase if the phase transitions during hydrogenating are merely dependent on the hydrogen content and not on the type of hydrogen isotopes. In order to deal with the gradient plateau region that originates from the inhomogeneous compositions of TiVCr alloys, a model relating αH-D in the single γ-phase to RP in the gradient plateau region was formulated. Furthermore, the values of αH-D were also determined by experiments for Ti0.3V0.4Cr0.3-hydrogen systems, and compared with the prediction results, providing validations to the formulated model.