Patent ID: 9646756
Date: 2017-05-09
CPC Classifications: B22F,H01F

Claim:
1. A powder magnetic core comprising: a compact of a mixed powder comprising: an iron-based soft magnetic powder whose surface has an electrical insulating coating; and a powder of a low magnetic permeability material having a heat-resistant temperature of 700° C. or higher than 700° C. and a relative magnetic permeability lower than a relative magnetic permeability of air, wherein an amount of the powder of the low magnetic permeability material in the mixed powder is 0.05 to 1.5% by volume, the relative magnetic permeability of the low magnetic permeability material is lower than 1.0000004, the low magnetic permeability material exists to replace a part, or all, of the air in a gap among particles of the iron-based soft magnetic powder in the compact and reduce magnetic permeability of the gap from the air, an average particle size of the powder of the low magnetic permeability material is 1 to 20 μm, the compact has a cross section or a surface in which an area ratio of the low magnetic permeability material is 1.5 to 30% when the cross section or the surface is observed at a magnification ratio of 1000 times, and the density of the compact is 6.7 Mg/m