Enhancing soft magnetic properties of FeSiBNbCu nanocrystalline powder cores by coating ZrO2 insulation layer

The insulation coating plays a crucial role in minimizing core loss ( P cv ) in soft magnetic powder cores (SMPCs). In this work, we prepared ZrO 2 coating layer on FeSiBNbCu spherical powder by the hydrolysis-precipitation method and investigated the magnetic properties of the FeSiBNbCu@ZrO 2 nanocrystalline SMPCs. ZrO 2 coating layer were successfully fabricated on the powder by adding a proper amount of K 2 ZrF 6 in alkaline ethyl alcohol solution. The micromorphology and chemical structure of the ZrO 2 coating layer on the surface of FeSiBNbCu nanocrystalline powder, as well as the conversion mechanisms, has been investigated. The presence of the ZrO 2 coating reduces the P cv by significantly lowers eddy loss ( P e ) of the nanocrystalline SMPCs, meanwhile improves DC bias performance and slightly decreases their permeability. When the additive amount of K 2 ZrF 6 is 1.0 wt%, the nanocrystalline SMPCs has best comprehensive soft magnetic properties, including stable effective permeability ( μ e ) of 57.8 up to 1 MHz, excellent DC bias performance of 59.3 % at a bias field of 100 Oe, and the lowest P cv of 194.7 mW/cm 3 at a frequency ( f ) of 150 kHz and maximum magnetic induction ( B m ) of 50 mT.