| 摘要 |
PROBLEM TO BE SOLVED: To provide a dust core made of soft magnetic powder of Fe-9.5 Si-5.5 Al-based alloy (Sendust alloy) with good DC superimposing characteristics, in which magnetic flux is not saturated under condition of large current in a coil and the permeability is not reduced. SOLUTION: Powder of soft magnetic alloy is made flat and an anisotropy characteristic in shape is shown, and an axis hard magnetization is generated vertically to a face of flat grains. The magnetic powder obtained in this way is subjected to pressed powder molding in a state of being oriented in a magnetic field vertically to a provisional magnetic path. Then, a dust core with a high counter magnetic field coefficient in a magnetic path of the magnetic core is obtained. In a choke coil manufactured with the dust core, an increase in magnetic flux against excitation by a DC is reduced and the saturation is prevented, so a rate of decrease in permeability can be improved greatly. As a result, a choke coil with a good DC superimposing characteristic can be obtained.
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