公开(公告)号：US20220059263A1

公开(公告)日：2022-02-24

申请号：US17421201

申请日：2020-03-11

Applicant: NGK SPARK PLUG CO., LTD.

Inventor： Hiroshi WATANABE ,  Satoshi MORI ,  Manami FUJII ,  Katsuya TAKAOKA ,  Hiroki TAKEUCHI ,  Hisashi KOZUKA

IPC: H01F1/20 ,  B22F1/00

Abstract: The iron loss of a dust core is reduced. A dust core (1) includes soft magnetic metal particles (3) having an average particle size of 5 μm or more and 30 μm or less, and a particle boundary phase (6). The particle boundary phase (6) includes a polycrystalline compound containing Al (aluminum). When a sectional structure of the dust core (1) is observed, an area percentage of α-Al2O3 in the particle boundary phase (6) is 75% or less. An average thickness Ta of the particle boundary phase (6) is 10 nm or more and 300 nm or less. According to the present invention, the iron loss is reduced.