SOFT-MAGNETIC IRON COMPOSITE POWDER FOR PRODUCING SOFT-MAGNETIC COMPOSITE MATERIAL WITH HIGH RESISTIVITY AND LOW IRON LOSS

摘要

A soft-magnetic iron composite powder for use in producing a soft-magnetic composite material having a high resistivity and a low iron loss, the powder comprising a soft-magnetic iron powder and an insulating coating film formed on the surface of the powder by the deposition of a magnesium-containing oxide. When the average particle diameter and the BET value of the soft-magnetic iron powder are expressed by D150 and BET1, respectively, then the soft-magnetic iron powder satisfies the requirements that D150 is 50-300 µm and BET1 D150 is 1.81-2.65. A powder collected by sieving the soft-magnetic iron powder with a sieve having a mesh value which is 1/2 the D150 satisfies the requirement BET2 D250 = 1.50-2.00, wherein D250 and BET2 are the average particle diameter and the BET value of the powder, respectively. Furthermore, the soft-magnetic iron powder has a roundness of 0.840-0.875 and a ruggedness of 0.940-0.948.