Low loss, high flux density powder cores made of ferrite-plated Fe-Si powders

Low loss, high flux density powder cores were successfully developed by compacting Ni-Zn ferrite plated Fe-Si powder. The ferrite-plated powder cores annealed at 150 and 400 /spl deg/C exhibited higher magnetic permeability than those of resin-coated powder cores annealed at the same temperatures. This higher permeability is attributed to a larger magnetic component in the compact using ferrite layer as insulation layer instead of non-magnetic silicone resin. The ferrite-coated powder cores showed low total power loss attributed to their high magnetic flux density compared to the resin-coated powder cores. These results indicate that the ferrite-coated cores are very promising for magnetic cores used in powder choke coils.