Thermal Stability and Hydrogen Desorption Behavior of Hydrogen-Induced Amorphous Alloys

概要

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Amorphous alloys prepared by hydrogenation of intermetallic compounds were thermally analyzed in an argon atmosphere by differential scanning calorimetry (DSC) to make clear the thermal stability and hydrogen desorption behavior of them. Much hydrogen gas desorb from the amorphous a-RM_2H_x alloys ( R is a rare earth metal and M is Fe, Co and Ni) prepared by hydrogenation of the C15 Laves compounds. On the contrary, little hydrogen gas desorb from the other amorphous alloys. These experimental results suggest that a large amount of hydrogen atoms are weakly trapped in a-RM_2H_x in which hydride non-forming metals are the main component of the alloys, while they are strongly trapped in the other amorphous alloys in which hydride forming metals are the main component of the alloys. The values of activation energies, determined by the Kissinger's technique, of crystallization for a-RM_2H_x and a-R_3AlH_x are about 150 kJ/mol, which are lower than those of the corresponding rapidly quenched hydrogen free amorphous alloys. On the other hand, the values for a-R_3GaH_x are about 85 kJ/mol. The crystallization temperatures of the amorphous alloys increase with increasing the melting point of the original compounds. The lower thermal stabilities of the gallium and indium based amorphous alloys are characterized by the low activation energies, the low enthalpy changes and the low crystallization temperatures.
東北大学の論文
1992-03-25