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Title:
IRON-BASED OXIDE MAGNETIC POWDER AND METHOD FOR MANUFACTURING SAME
Document Type and Number:
WIPO Patent Application WO/2021/065936
Kind Code:
A1
Abstract:
[Problem] To provide an iron-based oxide magnetic powder which has a sufficiently reduced amount of fine particles and coarse particles, has a powder shape that is close to a perfect sphere, and is suitable for magnetic recording medium applications. [Solution] A source solution containing ferric ions or ferric ions and metal element ions which substitute a portion of the Fe site and an alkali aqueous solution for neutralizing the source solution are added to a reaction system so that the reaction system has a pH of 1.0 to 3.0; a hydroxy carboxylic acid is added to the obtained reaction solution and thereafter the pH of the reaction system is neutralized to 7.0 to 10.0; a deposit of the obtained substituted metal element-containing iron oxyhydroxide is coated with a silicon oxide and heated to form particles of ε-iron oxide in which a portion of the Fe site is substituted with another metal element; and the slurry containing the particles is classified.

Inventors:
OHKOSHI Shin-ichi (3-1 Hongo 7-chome, Bunkyo-k, Tokyo 54, JP)
NAMAI Asuka (3-1 Hongo 7-chome, Bunkyo-k, Tokyo 54, JP)
TOKORO Hiroko (3-1 Hongo 7-chome, Bunkyo-k, Tokyo 54, JP)
YOSHIKIYO Marie (3-1 Hongo 7-chome, Bunkyo-k, Tokyo 54, JP)
YAMAGA Kazuhiro (4-14-1, Sotokanda, Chiyoda-k, Tokyo 21, JP)
MIYAMOTO Yasuto (4-14-1, Sotokanda, Chiyoda-k, Tokyo 21, JP)
MINEYAMA Yuki (4-14-1, Sotokanda, Chiyoda-k, Tokyo 21, JP)
SAKANE Kenji (4-14-1, Sotokanda, Chiyoda-k, Tokyo 21, JP)
KAWAHITO Tetsuya (4-14-1, Sotokanda, Chiyoda-k, Tokyo 21, JP)
Application Number:
JP2020/036984
Publication Date:
April 08, 2021
Filing Date:
September 29, 2020
Export Citation:
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Assignee:
THE UNIVERSITY OF TOKYO (Bunkyo-ku Tokyo, 54, JP)
DOWA HOLDINGS CO., LTD. (Sotokanda Chiyoda-k, Tokyo 21, JP)
International Classes:
C01G51/00; G11B5/706; G11B5/714; G11B5/84; C01G49/00; H01F1/11
Attorney, Agent or Firm:
KOMATSU Takashi (2-2-12 Nihonbashibakuro-cho, Chuo-k, Tokyo 02, JP)
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