Enhanced magnetic properties of FeSiAl soft magnetic composites prepared by utilizing phosphate: PSA as insulating layer

The phosphating treatment method has been extensively applied in the field of insulating soft magnetic powders because of its simplicity and ease of operation; however, the specific nanoscale morphology of phosphate coating layers and the interface/connection/interaction with the outer resin are still unclear. In this study, soft magnetic powder cores (SMPCs) with a nanoporous-structured phosphate coating were fabricated, in which the coating has a beneficial adsorption effect on the outer resin and can enhance the bonding force between the organic/inorganic coating. Optimized soft magnetic properties were obtained for the SMPCs with a phosphoric acid content of 0.6 wt%, including a high effective permeability of 61, low core loss of 134.6 mW/cm 3 (measured at 100 mT, 50 kHz), and high DC bias performance of 56% under a superimposed field of 100 Oe due to the favorable interactions between the insulating coating layers. These properties can be used to manufacture micro-magnetic components.