1. Effect of the Nb content on the amorphization process of the mechanically alloyed Fe–Co–Nb–B powders
- Author
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Jean-Marc Greneche, Achour Younes, Joan Josep Suñol, R. Bensalem, S. Souilah, and Safia Alleg
- Subjects
Materials science ,Mechanical Engineering ,Metallurgy ,Metals and Alloys ,Analytical chemistry ,Coercivity ,Nanocrystalline material ,law.invention ,Amorphous solid ,Tetragonal crystal system ,Differential scanning calorimetry ,Mechanics of Materials ,law ,Materials Chemistry ,Orthorhombic crystal system ,Crystallization ,Ball mill - Abstract
Mechanical alloying was used to prepare Fe 57 Co 21 Nb 7 B 15 (7Nb) and Fe 61 Co 21 Nb 3 B 15 (3Nb) powder mixtures in a high-energy planetary ball mill under argon atmosphere. Thermal stability, structural and magnetic properties were followed by differential scanning calorimetry, X-ray diffraction, vibrating sample magnetometry and Mossbauer spectrometry. For the Fe 57 Co 21 Nb 7 B 15 powders, an amorphous matrix (∼69%) where nanocrystalline bcc FeCo, bcc Nb(B), tetragonal Fe 2 B and orthorhombic Fe 3 B type phases were embedded is reached after 96 h of milling. However, for the Fe 61 Co 21 Nb 3 B 15 mixture, the partially amorphous structure (∼75%) is achieved within 48 h of milling. Further milling time (up to 96 h) gives rise to the primary crystallization of α-Fe in addition to bcc FeCo, orthorhombic FeB, tetragonal Fe 2 B and tetragonal Fe 3 B type borides. Lower Nb content powders (3Nb) exhibit higher saturation magnetization, Ms, higher coercive field, Hc, and lower glass transition temperature values than those of the 7Nb powders.
- Published
- 2012
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