Abstract
In this work,the influence of the hot-extrusion method on the hydrogen storage kinetics of Mg-Ni-Y alloy was investigated.It was shown that the extruded Mg91.47Ni6.97Y1.56 alloy exhibits improved hydriding and dehydriding(H/D)kinetics,with a capacity of 3.5 wt.％H2 absorption within 60 s and 5.4 wt.％H2 des-orption within 5 min at 573 K.The dehydrogenation activation energy of extruded alloy is 71.4 kJ mol-1,smaller than that of as-cast alloy(140.5 kJ mol1).The enhancement of H/D kinetics is attributed to the microstructural refinement and increased grain/phase boundaries introduced by hot extrusion,as well as the catalytic effects from the in-situ generated and grain-refined Mg2Ni and YH2 particles during the H/D process.Furthermore,the dehydrogenated rate-determining step transforms from hydrogen diffusion in the hydride(as-cast alloy)to the surface penetration of hydrogen atoms(extruded alloy).These findings provide crucial insights for the design of Mg-based hydrogen storage alloys in the future.
NETL
NSTL
万方数据