Formation of Mg<SUB>2</SUB>Ni from Mg and Ni Powder Mixtures by the Use of a Planetary Ball Mill

Abstract

Mg2Ni powder material can be synthesized from a mixture of Mg and Ni by its mechanical alloying using a planetary ball mill. The particle size of the mechanically alloyed Mg2Ni powder decreases with an increase in milling time, and the Mg2Ni phase in the milled mixture tends to change into poor crystalline structure in the prolonged milling operation. No significant exothermic reaction takes place during heating of the mechanically alloyed Mg2Ni powder except for the recrystallizing reaction at 430 K, while a considerable exothermic reaction due to the self-combustion is detected at around 860 K for the unmilled mixture followed by the ignition behavior of the starting powders at 780 K. There is no significant difference in the characteristic of hydrogen storage in the PCT diagram between the mechanically alloyed Mg2Ni powder and the thermally synthesized one.