An excellent soft magnetic Fe/Fe3O4-FeSiAl composite with high permeability and low core loss

It is well know that the high temperature annealing can improve the permeability and reduce the hysteresis loss of soft magnetic composites ( SMCs), but the eddy current loss would be accordingly increased. Thus, developing SMCs with high permeability and low core loss remains a challenge. Herein, we prepared a kind of Fe/Fe3O4-FeSiAl soft magnetic composites by replacing some Fe powders with FeSiAl, possessing high permeability and low core loss. In the fabricating process, reduced iron powders were coated with a FexOy insulating layer by surface oxidation method and the Fe/FexOy and FeSiAl alloy powders were used as raw materials to fabricate Fe/FexOy and Fe/FexOy-FeSiAl SMCs. Moreover, the optimum content of FeSiAl powders and the effects of high temperature annealing on the structure and performance of Fe/FexOy and Fe/FexOy-FeSiAl SMCs was investigated. These results of XRD, XPS and FTIR showed the Fe2O3 and Fe-OH existing in the FexOy insulating coating is gradually transformed to Fe3O4 under annealed at 550 degrees C, and the permeability and eddy current loss were greatly increased for Fe/FexOy SMCs. However, the permeability was highly increased but the eddy current loss stay unchangeable for Fe/FexOy-FeSiAl SMCs. These results strongly demonstrated the Fe/Fe3O4-FeSiAl SMCs have high permeability and low core loss.