Synthesis of amorphous and quasicrystal phases by mechanical alloying of Ti_45Zr_38Ni_17 powder mixtures, and their hydrogenation

摘要

Mechanical alloying of Ti_45Zr_38Ni_17 powder mixture forms an amorphous phase, but subsequent annealing causes the formation of an icosahedral (i) phase. The maximum hydrogen concentration that can he loaded at 573 K at a hydrogen pressure of 3.8 MPa is the same ([H]/[M] approx 1.5) for the amorphous and i-phase powders. With hydrogenation, the i-phase is almost stable, forming no hydrides, whereas the amorphous phase transforms to a fcc hydride. The activation energy for hydrogen desorption for the i-phase is about 127 kJ mol_(_1), which is lower than that for the amorphous phase, suggesting that the i-phase powder may have better properties for hydrogen-storage applications.