Absorption and Desorption Kinetics of Deuterium for ZrNi System

Because of the limited nature of elemental metals, most of the hydrogen storage materials are used as alloys. To apply hydrogen storage materials to tritium processing systems, it is indispensable to understand alloying effects on their properties such as storage, supply, recovery, separation and others to develop/design new materials. From this viewpoint, alloying effects on the ab/desorption, kinetics of deuterium for the Zr-Ni system was studied. It was revealed that the absorption of deuterium obeys first order kinetics with respect to the deuterium pressure, whereas, the desorption obeys second order kinetics with respect to the amount of deuterium absorption. In addition, alloying Zr with Ni caused an increase in the activation energy for absorption; on the contrary, the activation energies for desorption decreased. The heat of the deuterium solution and/or deuteride formation, evaluated through the proposed potential energy diagram, was found to decrease with increasing Ni content