Microstructure and hydrogenation behavior of ball-milled and melt-spun Mg-10Ni-2Mm alloys

Microstructure and hydrogen storage properties of a melt-spun Mg-10Ni-2Mm (at.%) alloy were studied in comparison with those of a conventionally prepared ball-milled one. The kinetics of H-absorption/desorption was improved through melt-spinning by obtaining nanograins in an amorphous matrix. The melt-spun ribbon alloy and the 2 h ball-milled alloy reached a maximum hydrogen storage capacity of ∼4.2 wt.% in 141 min and ∼3.2 wt.% in 210 min, respectively. Vacuum temperature desorption spectroscopy (TDS) (heating rate 5 °C/min) of the melt-spun alloy showed narrower desorption temperature range (220-330 °C), displaying a sharp joint peak at ∼286 °C than the 2 h ball-milled one (250-425 °C) with a broad peak around ∼310 °C. The species of hydrides were closely related to the microstructure. TEM micrographs and a sharp TDS peak demonstrated that the grains remained nano-sized in the melt-spun ribbons even after heating up to 350 °C during cycles. © 2007 Elsevier B.V. All rights reserved.