Hydrogenation of Zr-based metallic glasses and quasicrystals

Zr-based metallic glasses and quasicrystals were electrochemically charged with hydrogen. Hydrogen absorption/desorption as well as the influence of h ydrogen on the formation and stability of quasicrystals were studied by mea ns of X-ray diffraction, electron microscopy, differential scanning calorim etry (DSC) and thermal desorption analysis (TDA). In Zr69.5Cu12Ni11Al7.5 ab sorption kinetics and storage capacity were found to be better for the quas icrystalline than for the associated amorphous phase. Dissolved hydrogen wa s observed to play an important role not only in the stability of the quasi crystals, but also in their formation from glassy precursor material. Even hydrogen contents as low as 5 at.% changed the formation as well as the dec omposition of the icosahedral quasicrystals: the formation was shifted to h igher temperatures whereas decomposition temperatures were lowered. At larg er hydrogen contents, changes in both transformations were observed, yet no t fully understood. (C) 1999 Elsevier Science B.V. All rights reserved.