Preparation and properties of Mg-Fe and Mg-Ni-Fe nanocomposites

0177622 - UFM-A 20013270 RIV SIGLE SK eng C - Konferenční příspěvek (zahraniční konf.)
Schneeweiss, Oldřich - Jirásková, Yvonna - Šebek, Josef - Lin, S. - Yao, X.
Preparation and properties of Mg-Fe and Mg-Ni-Fe nanocomposites.
11th Czech and Slovak Conference on Magnetism CSMAG'01 - Programme & Abstracts. Košice: Šafarik University Košice, 2001, s. 55.
[Czech and Slovak Conference on Magnetism /11./. Košice (SK), 20.08.2001-23.08.2001]
Grant CEP: GA ČR GA106/99/0183; GA ČR GA202/01/0668; GA MŠMT ME 209
Výzkumný záměr: CEZ:AV0Z2041904
Klíčová slova: nanocrystals * magnetism * Mössbauer spectroscopy
Kód oboru RIV: BM - Fyzika pevných látek a magnetismus

We prepared Mg-Fe and Mg-Fe-Ni nanocomposites using spark synthesis of pure Mg, and Fe or permalloy (Ni3Fe) electrodes. The magnetic separation and sedimentation treatments were used for separation of nanocrystaline parts from the as-prepared powders. In the Mg-Fe sample, a-Fe, Fe in Mg, and FeO phases were determined using the Mössbauer phase analysis, and Mg, MgO, and a-Fe by the x-ray diffraction measurements. The Fe in Mg phase with approx. 8at.% Fe is a new metastable phase not described in equilibrium phase diagram handbooks until now. Its temperature dependence of magnetization showed spin-glass like behaviour of the sample. An annealing in vacuum (10-3 Pa) or in the protective atmosphere (H2) caused transformation of the Fe in Mg phase into a-Fe. With increasing a-Fe content an increase of the FeO was observed. The Mg-Fe-Ni nanocomposite exhibits similar behaviour and phase composition but the Ni3Fe phase was replaced the a-Fe and different features of the Fe(Ni) in Mg phase were observed. Both Mg-Fe and Mg-Ni-Fe exhibited a high adsorption capacity to hydrogen and air moisture.
Trvalý link: http://hdl.handle.net/11104/0074541