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Synthèse et caractérisation de poudres magnétiques pour aimants nanocomposites

Abstract : The synthesis of nanocomposite permanent magnets composed of a mixture of a hard magnetic phase, with high coercivity, and of a soft magnetic phase, with high magnetization, is one of the possible paths to obtain new rare earth free permanent magnets materials. In this work, the Fe65Co35 phase has been chosen as the soft phase and the SrFe12O19 phase has been chosen as the hard phase. Nanometric powders have been chemically synthesized, adapting existing processes. Fe65Co35 nanoparticles about 10 nm in size were synthesized by the polyol method, in the presence of RuCl3 as nucleating agent. The synthesis of SrFe12O19 nanoparticles was carried out by a so-called “modified sol-gel” method developed in this work. This method, which consists of calcination in a NaCl matrix, allows obtaining monodomain nanoparticles that are well dispersed and have magnetic properties superior to those obtained by the conventional sol-gel route. The assembly of hard and soft phases was carried out by a so-called "in-situ" method, for which SrFe12O19 nanoparticles are introduced into the reaction medium during the synthesis of the Fe65Co35 nanoparticles. Magnetic exchange coupling was obtained for nanocomposites with 5% and 10% Fe65Co35 phase contents.
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Submitted on : Wednesday, April 14, 2021 - 2:12:13 PM
Last modification on : Thursday, April 15, 2021 - 3:53:57 AM

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  • HAL Id : tel-03198009, version 1

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Kalthoum Nakouri. Synthèse et caractérisation de poudres magnétiques pour aimants nanocomposites. Autre [cond-mat.other]. Normandie Université, 2020. Français. ⟨NNT : 2020NORMR098⟩. ⟨tel-03198009⟩

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