Characterization of a magnesium-based alloy after hydriding-dehydriding cycling (n=1–150)

Abstract

The cycling performance of Mg-15 wt% Ni-5 wt% Fe2O3 alloy (named Mg-15Ni-5Fe2O3) was investigated by measuring the absorbed hydrogen quantity as a function of the number of cycles and by examining the variations in the phases and microstructures with cycling. The sample was hydriding-dehydriding cycled 150 times. The absorbed hydrogen quantity decreased as the number of cycles increased from the second to the 150th cycle. The Ha value varied almost linearly with the number of cycles. The maintainability of the absorbed hydrogen quantity was 73.8%, and the degradation rate was 0.007 wt%/cycle for the hydriding reaction time of 60 min. After the 9th hydriding-dehydriding cycle, Mg, Mg2Ni, MgO, and Fe were observed. After 150 cycles, the quantity of the MgO increased. The phases were analyzed using MDI JADE 6.5, a software system designed for XRD powder pattern processing, from the XRD pattern of the Mg-15Ni-5Fe2O3 alloy after the 9th hydriding-dehydriding cycle. The crystallite size and strain of the Mg were then estimated using the Williamson-Hall technique.