Title:
フェライト焼結磁石及びこれを備える回転電気機械
Document Type and Number:
Japanese Patent JP7275740
Kind Code:
B2
Abstract:
A ferrite sintered magnet 100 comprises M-type ferrite crystal grains 4 having a hexagonal crystal structure, two-crystal grain boundaries 6a formed between two of the M-type ferrite crystal grains 4, and multiple-crystal grain boundaries 6b surrounded by three or more of the M-type ferrite crystal grains 4. This ferrite sintered magnet 100 contains at least Fe, Ca, B, and Si, and contains B in an amount of 0.005 to 0.9 mass % in terms of B2O3, the two-crystal grain boundaries 6a and the multiple-crystal grain boundaries 6b contain Si and Ca, and in a cross-section parallel to a c-axis of the ferrite sintered magnet, when the number of multiple-crystal grain boundaries having a maximum length of 0.088 or more and less than 0.49 μm per cross-sectional area of 76 μm2 is P, P is 8 or more.
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Inventors:
Kidou Murakawa
Shogo Muroya
Hiroyuki Morita
Masaki Ikeda
Shogo Muroya
Hiroyuki Morita
Masaki Ikeda
Application Number:
JP2019059952A
Publication Date:
May 18, 2023
Filing Date:
March 27, 2019
Export Citation:
Assignee:
TDK Corporation
International Classes:
H01F1/10; C04B35/26; H01F41/02
Domestic Patent References:
| JP2017005004A | ||||
| JP2015181147A | ||||
| JP2017126719A |
Foreign References:
| WO2012090935A1 | ||||
| WO2014021149A1 | ||||
| WO2014050433A1 | ||||
| WO2011001831A1 | ||||
| WO2018216594A1 |
Attorney, Agent or Firm:
Yoshiki Hasegawa
Yoshiki Kuroki
Takashi Mikami
Yoshiki Kuroki
Takashi Mikami