Amorphous phase formation, crystallization process and metastable phase of La5M35Ge60 (M = Mn, Fe, Co, Ni, Cu, Pd) ternary alloys

Formation of La5M35Ge60 (M = Mn, Fe, Co, Cu, Pd) amorphous alloys has been investigated using a single-roller spinning technique. It is found that an amorphous phase of La5M35Ge60 (M = Mn, Co, Pd) is prepared. Crystallization process of the amorphous alloys and formation of the metastable phase have been studied by DSC and X-ray diffraction measurement and compared to those of La5Ni35Ge60 which was reported to form a metastable non-stoichiometric BaAl4-type compound on crystallizing through a polymorphic transformation. It is found that new stable compound(s) is (are) formed with Ge by crystallizing from the La5Mn35Ge60 amorphous alloy. It is also found that any new metastable and stable phases are not formed in the crystallization process of the La5Pd35Ge60 amorphous alloy. In the case of La5Co35Ge60, a metastable CoGe2 non-stoichiometric compound is formed with LaCoGe3 and Co5Ge7 compounds on crystallizing. These results indicate that the crystallization processes of the La5M35Ge60 (M = Mn, Co, Ni, Pd) amorphous alloys are considerably different from one another. (c) 2005 Elsevier B.V. All rights reserved.