Hitachi Metals, Ltd.

Tetsuroh Katoh

Shin Noguchi

Kazunori Nishimura

Toshio Mihara

Yoshimasa Nishio

A powder magnetic core manufacturing method includes: a first step of mixing a binder with a soft magnetic material powder containing Fe-M (M: Al or Cr)-based alloy particles on which an insulating layer is formed; a second step of filling a pressing die with a mixture obtained through the first step, subjecting the mixture to pressing to obtain a green compact, and slidingly demolding the green compact from the pressing die; a third step of processing the green compact after the second step and removing expansion deformed matter of the alloy particles present in a region of pressing flaws formed on a surface of the green compact during the slidingly demolding; and a fourth step of subjecting the green compact after the third step to heat treatment to oxidize surfaces of the Fe-M (M: Al or Cr)-based alloy particles at high temperature, so that the oxide phase is formed.

Method for manufacturing powder magnetic core

A method for manufacturing a powder magnetic core using a soft magnetic material powder, wherein the method has: a first step of mixing the soft magnetic material powder with a binder, a second step of subjecting a mixture obtained through the first step to pressure forming, and a third step of subjecting a formed body obtained through the second step to heat treatment. The soft magnetic material powder is an Fe&#x2014;Cr&#x2014;Al based alloy powder comprising Fe, Cr and Al. An oxide layer is formed on a surface of the soft magnetic material powder by the heat treatment. The oxide layer has a higher ratio by mass of Al to the sum of Fe, Cr and Al than an alloy phase inside the powder.

Powder magnetic core, and coil component

A magnetic core has a high initial permeability and a small core loss, reducing a core loss at high frequencies; and a coil component including the same. This magnetic core is formed by binding a plurality of Fe-based alloy particles containing Al via an oxide layer containing an Fe oxide. In an X-ray diffraction spectrum of the magnetic core measured using Cu-K&#x3b1; characteristic X-rays, a peak intensity ratio (P1/P2) of peak intensity P1 of a diffraction peak derived from the Fe oxide having a corundum structure appearing in the vicinity of 2&#x3b8;=33.2&#xb0; to peak intensity P2 of a diffraction peak derived from the Fe-based alloy having a bcc structure appearing in the vicinity of 2&#x3b8;=44.7&#xb0; is 0.010 or less (excluding 0). A superlattice peak intensity of an FeAl ordered structure is at most a noise level within a range of 2&#x3b8;=20&#xb0; to 40&#xb0;.

Magnetic core and coil component

Provided are a magnetic core having a high initial permeability and a coil component including the same. The magnetic core has an X-ray diffraction spectrum of the magnetic core measured using Cu-K&#x3b1; characteristic X-rays, wherein a peak intensity ratio (P1/P2) of a peak intensity P1 of a diffraction peak of an Fe oxide having a corundum structure appearing in a vicinity of 2&#x3b8;=33.2&#xb0; to a peak intensity P2 of a diffraction peak of the Fe-based alloy having a bcc structure appearing in a vicinity of 2&#x3b8;=44.7&#xb0; is 0.015 or less; and in the X-ray diffraction spectrum, a peak intensity ratio (P3/P2) of a peak intensity P3 of a superlattice peak of an FeAl ordered structure appearing in a vicinity of 2&#x3b8;=26.6&#xb0; to the peak intensity P2 is 0.015 or more and 0.050 or less.

Growing community of inventors

Minato-ku, Japan

Tetsuroh Katoh