Improvement of hydriding properties of a Zr1Ni1 alloy by adding third transition metals for tritium recovery

For tritium handling, application of a Zr1Ni1 alloy was attempted. In order to decrease the equilibrium hydrogen pressure in hydriding the Zr1Ni1 alloy, substitutions of Ni in Zr1Ni1 alloy by either Fe, Co or Cr were conducted. The equilibrium hydriding pressure of the Zr1Ni1 alloy was decreased by the substitution and the contribution of the Fe substitution on the decrease of the equilibrium hydrogen pressure of the Zr1Ni1 was greatest. Moreover, the equilibrium hydrogen pressures of these alloys showed a close relationship with lattice parameters of the alloys. Therefore, design of the alloy with a desired equilibrium pressure became possible by controlling the lattice parameters of the alloys. Furthermore, it was confirmed that the Zr1Ni0.8Fe0.2 alloy showed faster reaction kinetics than the Zr1Ni1 alloy, where the reaction rate of the alloy was twice that in Zr1Ni1. Though pulverizing during hydriding was observed in both the Zr1Ni1 and the Zr1Ni0.8Fe0.2 alloys, the powdering of these alloys was smaller compared with a generally used hydrogen-absorbing alloy. (C) 1998 Elsevier Science B.V. All rights reserved.