Oxidation fabrication and enhanced soft magnetic properties for core-shell FeCo/CoFe_2O_4 micron-nano composites

摘要

FeCo/CoFe2O4 micron-nano composites have been fabricated by controllably oxidizing micron-sized FeCo particles. High-purity 60-nm-thick CoFe2O4 layers can be formed in situ on the surface of the unoxidized FeCo particles to form a dense FeCo/CoFe2O4 core-shell structure. The good intrinsic magnetic properties, including a high saturation magnetization of 210 A. m(2). kg(-1) and a low coercivity of 11.7 Oe, are obtained in these FeCo/CoFe2O4 composites due to the nanoscale thickness of the ferrimagnetic CoFe2O4 layers. For traditional soft magnetic composites, low core loss can only be obtained by seriously sacrificing their magnetic induction. In this work, balanced soft magnetic properties with low core loss and high magnetic induction are obtained in the fully compacted FeCo/CoFe2O4 composites, which promise great potential applications in high-power and high frequency magnetic devices. This controlled surface oxidation may also provide an effective surface treatment for metal-based soft magnets to improve their overall performance. (C) 2017 Elsevier Ltd. All rights reserved.