Improvement of high-frequency magnetic properties and loss characteristics of flaky FeSiAl coated with Ni0.4Zn0.6Fe2O4

Abstract

As a hotspot of soft magnetic composites (SMCs), the magnetic properties and loss characteristics of FeSiAl SMCs at high frequency need to be further optimized. In this study, the FeSiAl with flaky morphology was obtained by mechanical ball milling to improve its permeability, the reduction of power loss and the optimization of magnetic properties were achieved by the Ni0.4Zn0.6Fe2O4 cladding layer. For comparison, phosphoric acid-passivated flaky FeSiAl was prepared. The results indicated that due to the good coating effect and high resistivity of NiZn ferrite, the Ni0.4Zn0.6Fe2O4 coated flaky FeSiAl has a high permeability (μe ≈ 100) with extraordinary frequency stability in the range of 100 kHz–10 MHz, a higher quality factor with the peak occurs in higher frequency bands (Q = 72 at around 1 MHz), and a low relative loss factor of the order of 10−3–10−4 in the range of 20 kHz–8 MHz. In addition, the ferrite-coated flaky FeSiAl also has outstanding high-frequency power loss performance, which can be explained by the coercivity in the VSM results and the reduced eddy current loss obtained by loss separation. This work broadens ideas for improving high-frequency applications of FeSiAl SMCs.