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|Title:||Improved activation and hydrogen storage properties of an amorphous Mg85Ni15 melt-spun alloy via surface treatment with NH4+ solution|
|Published:||October 13, 2011|
|Abstract:||An amorphous Mg85Ni15 melt-spun hydrogen storage alloy, processed by submersion in an aqueous solution of NH4+, is able to absorb >5 wt. % hydrogen at 473 K during the first hydrogenation cycle. The nanocrystalline microstructure formed during devitrification of the metallic glass is preserved by the lower required activation temperature of the NH4+-treated material; and the kinetics of subsequent absorption/desorption cycles at 573 K are dramatically improved, compared to the as-spun material. DSC experiments and thermodynamic calculations demonstrate that the decreased crystallite size of the 473 K activated material lowers the hydride decomposition temperature by 20 K to 50 K, in contrast to a sample activated at 573 K. The NH4+-treatment of a glassy alloy presented here provides a more practical approach to both forming a nanocrystalline material, and facilitating activation, compared to ball milling; requiring much less time and a more commercially scalable option.|
|Citation:||Journal of Alloys and Compounds|
|Keywords:||Mg-based alloy, metallic glass, hydrogen storage, metal hydride, nanocrystalline|
|Research Areas:||Nanomaterials, Thermodynamics and kinetics, Energy Conversion, Storage, and Transport|
|PDF version:||Click here to retrieve PDF version of paper (4MB)|