Mechanochemical synthesis of an icosahedral phase of composition Ti45Zr38Ni17 and its interaction with hydrogen

An icosahedral phase of composition Ti45Zr38Ni17 was synthesized, and its i nteraction with hydrogen was studied. It was shown that, unlike icosahedral phases of the same composition formed by the fast hardening of a melt or b y the annealing of alloys, the hydrogenation of the mechanochemically synth esized icosahedral phase at 230 degreesC has no induction period and begins at a maximum rate even at hydrogen pressures lower than 1 atm. Analysis of an experimental hydrogen pressure-icosahedral phase composition isotherm a nd XRD data suggests that the hydrogen absorption by the icosahedral phase is similar to that for hydrides. This phenomenon was explained based on the assumption that, in the structure of the hydrogenated icosahedral phase, t here are two types of hydrogen: chemically bonded hydrogen occupying distor ted tetrahedral positions in Bergman structure-forming icosahedral clusters and hydrogen located between these clusters in the form of a solid solutio n.