Effect of rotation speed on hydrogen storage properties of Ti₄₅Zr₃₈Ni₁₇ alloy ribbons produced by melt spinning

Abstract Ti/Zr-based icosahedral (i) quasicrystals are believed to have a Bergman-type cluster with a large number of tetrahedral interstitials, making them attractive as potential hydrogen storage materials. In this study, Ti 45 Zr 38 Ni 17 alloy ribbons were prepared by melt spinning at different rotation speeds, and the effect of the rotation speed on the microstructures and hydrogen storage capacities was investigated. The i-phase with a small amount of Ti 2 Ni phase and/or some minor crystal phase was identified after melt spinning, but the amount of amorphous phase increased and the Ti 2 Ni and the other crystal phases decreased with increasing rotation speed. After gaseous hydrogen loading at 573 K and a pressure of 3 MPa, a hydride phase was observed in the samples with more amorphous phase, suggesting that the amorphous phase turned into the hydride phase. The maximum gaseous hydrogen capacity (H/M), 1.31, was obtained for the sample with more i-phase. After electrochemical hydrogen loading, a slightly higher maximum discharge capacity was observed in a less-quality quasicrystal sample at the first loading, that decreased drastically after the second cycle, but gradually increased with increasing cycling up to 20 cycles. The maximum hydrogen discharge capacity obtained in sample with more i-phase, reached about 10 mAh/g, while the less-amount one 4 mAh/g, suggesting the i-phase has higher hydrogen capacity than the crystal and the amorphous phases.