The core-shell structured Fe-based amorphous magnetic powder cores with excellent magnetic properties

The Fe-based soft magnetic amorphous powder cores (AMPCs) with excellent comprehensive magnetic properties were successfully designed and fabricated using the core-shell structured FeSiBCCr/TiO2 composite powders. The influence of the concentration of water (H2O) for the magnetic performance of the AMPCs has been systematically studied based on careful analysis of the process of nucleation and growth of TiO2 under different H2O concentration in the reaction system. The growth process for the TiO2 coating layer with the H2O concentration in the range of 0.01-0.02 ml/g corresponds to the heterogeneous nucleation phase, while the mixing phase of heterogeneous and homogeneous nucleation occurs when the concentration of H2O increases to 0.03 ml/g. Optimized soft magnetic properties have been achieved for the AMPCs with H2O concentration of 0.02 ml/g, including high permeability of 81.5 with a high frequency stability up to 10 MHz, high quality factor of 102 at 530 kHz, low core loss of 42 mW/cm(3) at 500 kHz for B-m = 0.01 T, and better DC-bias property of 52% at a bias field of 100 Oe due to the uniform and proper thickness insulation coating layer, which can be used to produce miniature magnetic components for applications in medium and high-frequency fields. (C) 2019 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.