Cluster structure and hydrogen in Ti-Zr-Ni quasicrystals and approximants

Elastic neutron diffraction data from icosahedral Ti₄₅Zr₃₈Ni₁₇ are presented and analyzed using information from the 1/1 approximant Ti₅₀Zr₃₅Ni₁₅. These data indicate that similar clusters exist in the approximant and the i-phase. This is shown to be consistent with simulated diffraction from an icosahedral glass model of the quasicrystal, placing a Bergman cluster on the glass sites. An electrochemical method was used to hydrogenate Ti-based quasicrystals and their crystal approximants. This technique gives a consistently high hydrogen to metal atom ratio of 1.9, without crystal hydride formation in the quasicrystal.