Study of the properties of ZrCo0.8M0.2 (M = Co, Cu, Cr, Mn, Al) alloys for tritium storage

Abstract:

ZrCo_0.8M_0.2 (M = Co, Cu, Cr, Mn, and Al) alloys were prepared via the arc melting method in an argon atmosphere. The major phase of the alloys arranges itself in a ZrCo structure. The partial addition of Cr, Mn, and Al leads to the formation of a secondary phase. The Zr₂Co and ZrCr₂ phases, the Zr₂Co and ZrMn₂ phases, and the Zr₃Co and Zr₆CoAl₂ phases are formed upon Cr, Mn, and Al substitution, respectively. The cell volume of the alloys decreases upon Cr and Mn substitution, and increases upon Cu and Al replacement. Moreover, the hydrogen storage capacity of the alloys decreases when Cu, Cr, Mn, or Al are present in the alloy. However, the plateau of the desorption pressure remains nearly unchanged for all the alloys. The ZrCo alloy activation performance drastically improves upon Cr and Mn addition at room temperature, while the disproportionation reaction rate decreases, due to the decrease in its driving force. A modification of the 8f₂ and 8e sites results in a change in the disproportionation driving force in all the investigated alloys.