Kobe Steel, Ltd.

Hitachi Powdered Metals Co., Ltd.

Sohei Yamada

Chio Ishihara

Hiroyuki Mitani

Nobuaki Akagi

Hirofumi Houjou

Makoto Iwakiri

Yasukumi Mochimizo

Yasukuni Mochimizo

An iron-based magnetic powder for dust cores has layers of phosphoric acid-based film and silicone resin film sequentially formed on the surface thereof. The phosphoric acid-based film contains at least one element selected from the group consisting of Co, Na, S, Si, and W. The iron-based powder effectively keeps insulation among iron powder particles, excels in mechanical strength even though the amount of insulating material is reduced due to achieve high-density forming, and exhibits good thermal stability necessary for electrical insulating properties even after high-temperature heat treatment.

Iron-based soft magnetic powder for dust core, method for production thereof, and dust core

The present invention relates to an iron-base powder for a powder core, wherein when cross-sections of at least 50 iron-base powders are observed and a crystal grain size distribution containing at least a maximum crystal grain size is determined by measuring a crystal grain size of each iron-base powder, 70% or more of the measured crystal grains are a crystal grain having a crystal grain size of 50 &#x3bc;m or more. According to the iron-base powder of the invention, a coercivity of the powder core can be made small and a hysteresis loss can be reduced.

Powder core and iron-base powder for powder core

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Kosai, Japan

Sohei Yamada