• Żurawicz, J. K.
• Vasilyeva, O. Ya.
• Kubalova, L.
• Pikula, T.
• Fedotov, S. A.
• Oleszak, Dariusz
• Jartych, E.

Abstract

<p>Mechanical alloying method was applied to prepare the Fe₇₅Ge₂₅, Fe₆₂Ge₃₈and Fe_33.3Ge_66.7alloys. X-ray diffraction, differential scanning calorimetry and Mössbauer spectroscopy were used as complementary methods to obtain structural data and hyperfine interaction parameters for the as-milled as well as the heated samples. After mechanical alloying process the disordered α-Fe(Ge) solid solution was formed in the case of Fe₇₅Ge₂₅composition and it was characterized by the broad hyperfine magnetic field distribution with the average field of about 25 T. Heat treatment up to 873 K resulted in the formation of the mixture of three ordered phases and α-Fe(Ge) solid solution. The ordered phases were: metastable D0₃phase with two hyperfine magnetic fields of 32.8 and 20.2 T and two equilibrium phases-hexagonal ε and cubic ε′ with fields of about 24.6 and 23.6 T, respectively. After heating up to 973 K this mixture transformed into the mixture of ε and ε′ phases. In the case of Fe₆₂Ge₃₈composition the hexagonal β-Fe₃Ge₂phase was obtained during mechanical alloying process. This phase was stable after heat treatment up to 973 K. The as-milled and heated samples were characterized by similar Mössbauer spectra, which were a superposition of the sextets with various hyperfine magnetic fields what reflected different configurations of germanium atoms around⁵⁷Fe atoms. In the case of Fe_33.3Ge_66.7composition the ordered tetragonal FeGe₂phase was obtained and it was stable during heat treatment up to 973 K. Mössbauer measurements revealed the single paramagnetic line with the isomer shift of 0.30(1) mm/s characteristic for the FeGe₂intermetallic phase. © 2006 Elsevier B.V. All rights reserved.</p>

Topics

• x-ray diffraction
• differential scanning calorimetry
• intermetallic
• Germanium
• Mössbauer spectroscopy
• ordered phase