Münster 1999 – scientific programme
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M: Metallphysik
M 3: Quasikristalle I
M 3.1: Talk
Monday, March 22, 1999, 10:15–10:30, S 9
Influence of Hydrogen on Formation and Thermal Stability of Zr-Based Quasicrystals — •Noam Eliaz1, Daniela Zander2, Uwe Köster2, and Dan Eliezer1 — 1Dept. Materials Engineering, Ben Gurion University of Negev, Beer-Sheva 84105, Israel — 2Fachbereich Chemietechnik, Universität Dortmund, D-44221 Dortmund, Germany
The high number of potential interstitial sites for hydrogen and the favorable hydrogen-metal chemistry make quasicrystalline alloys candidates for hydrogen storage applications. Zr- as well as Ti-based quasicrystals have been observed recently to store hydrogen up to a content close to the best crystalline materials. The objective of this report is to present our results on the effect of hydrogen on the formation of Zr69.5Cu12Ni11Al7.5 quasicrystals from the glassy precursor material as well as on their thermal stability. Samples were charged electrochemically with hydrogen in a glycerine-phosphoric acid electrolyte. Hydrogen was observed to have a significant effect not only on the stability of the quasicrystals, but also on their formation from the glassy precursor material. Formation of quasicrystals could be observed only if the hydrogen content of the glassy precursor is less then 5 at. spectroscopy (TDS) to occur prior to the decomposition of the quasicrystalline phase. DSC reveals that with increasing hydrogen content the decompostion of the icosahedral quasicrystals is shifted to lower temperatures. The micromechanism of the decomposition was studied in detail by means of TEM and will be discussed in detail.