High density Fe-based soft magnetic composites with nice magnetic properties prepared by warm compaction

The influences of compacting temperature (Tc), molding pressure (Pm), contents of lubricant (Cl) and binder (Cb) on the compacted density (ρc) and its comprehensive soft magnetic properties for the FeSiCr soft magnetic composites (SMCs) fabricated by warm compaction were systematically studied. Appropriate increase of Tc is beneficial to improve the surface lubrication effect of magnetic powders during the forming process of SMCs, thus giving rise to the increase of ρc and the decrease of porosity fraction for the SMCs. Under this situation, the resistance of domain rotation and domain wall displacement in the SMCs during magnetization process is reduced, which is finally in favor of the improvement of SMCs’s soft magnetic properties. The results of loss separation show that the Ph value plays a dominant role in the variation trend of Pcv value for the FeSiCr-SMCs in the test frequency range of 20–200 KHz, wherein the ratio of Ph/Pcv is large than 81 %. Under the optimized process parameters of Tc= 110 ℃, Pm= 600 MPa, Cl= 1.5 wt. % and Cb = 2.5 wt. %, the ρc of FeSiCr-SMCs increases by 8.14 % to 6.38 kg/m3, and the SMCs exhibit better comprehensive soft magnetic properties compared with those at Tc = 25 ℃. Hereinto, μe increases by 19.89 % to 45.8 @ 100 kHz, Pcv decreases by 26.11 % to 495.8 kW/m3@f= 100 kHz, Bm= 50mT, and μe % reached 85.5 % at H = 8000 A/m. These results indicated that the warm compaction process is one of the effective ways to further promote Fe-based SMCs to meet the development requirements of high-frequency, miniaturization and high-power of electronic equipment.