The effect of heat treatment on the electrode characteristics of the ball-milled Zr-Cr-Ni

Electrodes of Zr-Cr-Ni alloys have been prepared by the ball milling process, starting from the arc-melted Zr(Cr0.5Ni0.5)2 alloy and from the mixtures of elemental Zr, Cr and Ni powders. The nanocrystalline C14 structure has been obtained by either ball milling the arc-melted alloy or heat-treating the ball-milled Zr-Cr-Ni powders. The plateau pressure for hydrogenation of nanocrystalline alloys was lower than that of conventionally produced alloys. The heat-treated Zr-Cr-Ni powders showed a similar discharge capacity as the arc-melted alloy, but the activation was much easier. The structure and phase transformation occurring during the ball milling and heat-treating were analyzed and discussed. (orig.)