By measuring the absorbed hydrogen quantity as a function of number of cycles, cycling characteristics of the Mg-15 wt%Ni-5 wt%Fe2O3 alloy was investigated. 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 H-a value varied almost linearly with the number of cycles. The degradation rate from n = 1 to n = 100 is 0.01201 wt%/cycle for the hydriding reaction time of 10 min, and 0.00860 wt%/cycle for the hydriding reaction time of 60 min. After the 150th hydriding-dehydriding cycle, Mg, Mg2Ni, Mg(OH)(2), MgO, and Fe were observed. The phases were analyzed by Rietveld analysis from the XRD patterns of the Mg-15Ni-5Fe(2)O(3) alloy after 150th hydriding-dehydriding cycles. The crystallite size and strain of Mg were then estimated by Williamson-Hall technique. (C) 2012 Elsevier Ltd. All rights reserved.