公开(公告)号：US20220162089A1

公开(公告)日：2022-05-26

申请号：US17433684

申请日：2020-03-13

Applicant: DOWA ELECTRONICS MATERIALS CO., LTD.

Inventor： Tatsuro HORI ,  Daisuke KODAMA ,  Shiho OBATA ,  Masahiro GOTOH

IPC: C01G49/06 ,  C08K3/22 ,  H05K9/00

Abstract: A substituted ε-iron oxide magnetic particle powder having a reduced content of an α-type iron-based oxide and Fe sites of ε-Fe2O3 partially substituted by another metal element is obtained by neutralizing an acidic aqueous solution containing a trivalent iron ion and an ion of a metal that partially substitutes Fe sites to a pH of between 2.0 and 7.0. Thereafter, a silicon compound having a hydrolyzable group is added to a dispersion liquid containing an iron oxyhydroxide having a substituent metal element or a mixture of an iron oxyhydroxide and a hydroxide of a substituent metal element. The dispersion liquid is neutralized to a pH of 8.0 or higher and the iron oxyhydroxide having a substituent metal element or the mixture of the iron oxyhydroxide and the hydroxide of a substituent metal element is coated with a chemical reaction product of the silicon compound. The dispersion is then heated.

公开(公告)号：US20220081319A1

公开(公告)日：2022-03-17

申请号：US17419346

申请日：2020-02-04

Applicant: DOWA ELECTRONICS MATERIALS CO., LTD. ,  THE UNIVERSITY OF TOKYO

Inventor： Shin-ichi OHKOSHI ,  Asuka NAMAI ,  Marie YOSHIKIYO ,  Daisuke KODAMA ,  Shiho OBATA ,  Masahiro GOTOH

IPC: C01G49/06 ,  H01F1/34 ,  H01F41/00

Abstract: An iron-based oxide magnetic powder has good thermal stability and a small change in coercive force even in a high-temperature environment and is one composed of particles of ε-iron oxide in which Fe sites are partially substituted by another metal element. A production method for such an iron-based oxide magnetic powder includes allowing a phosphorus-containing ion to coexist when a precipitate of an iron hydroxide containing a substituent metal element produced by neutralizing an acidic aqueous solution containing a trivalent iron ion and an ion of a metal that partially substitutes Fe sites is coated with silicon oxide using a silane compound.

公开(公告)号：US20220089456A1

公开(公告)日：2022-03-24

申请号：US17433672

申请日：2020-02-28

Applicant: DOWA ELECTRONICS MATERIALS CO., LTD.

Inventor： Tatsuro HORI ,  Daisuke KODAMA ,  Shiho OBATA ,  Masahiro GOTOH

IPC: C01G51/00 ,  C08K3/22 ,  H01F1/34 ,  H05K9/00

Abstract: A substitution-type ε-iron oxide magnetic particle powder having a reduced content of a non-magnetic α-type iron-based oxide and Fe sites of ε-Fe2O3 partially substituted by another metal element is obtained by neutralizing an acidic aqueous solution containing a trivalent iron ion and an ion of a metal that partially substitutes Fe sites to a pH of 2.0 or higher and 7.0 or lower. A silicon compound having a hydrolyzable group is added to a dispersion liquid containing an iron oxyhydroxide having a substituent metal element or a mixture of an iron oxyhydroxide and a hydroxide of a substituent metal element. The dispersion liquid is neutralized to a pH of 8.0 or higher and the iron oxyhydroxide having a substituent metal element or the mixture of the iron oxyhydroxide and the hydroxide of a substituent metal element is coated with a chemical reaction product of the silicon compound and then heated.