Amelioration of the hydriding and dehydriding kinetics of Mg by pulverization and the formation of Mg 2Ni hydride

Abstract

The addition of an oxide Fe 2O 3 is considered to increase the hydriding rate of Mg by pulverization, and the addition of Ni to increase the hydriding and dehydriding rates by the formation of Mg 2Ni hydride. The sample Mg–10 wt.% (Fe 2O 3, Ni) was prepared by grinding Mg mechanically under H 2 (reactive mechanical grinding) with nano-structured Fe 2O 3 particles and Ni. The as-milled sample absorbed 4.24 wt.% hydrogen at 593 K under 12 bar H 2 for 60 min. Its activation was accomplished after two hydriding–dehydriding cycles. The activated sample absorbed 4.05 wt.% hydrogen at 593 K, 12 bar H 2 for 60 min and desorbed 3.05 wt.% hydrogen at 593 K, 1.0 bar H 2 for 60 min. After hydriding–dehydriding cycling, Mg 2Ni is formed by the reaction of Mg with Ni, Fe 2O 3 is reduced, and a small fraction of Mg is oxidized.