Ferrite sintered magnet and rotary electrical machine comprising the same
AssigneeTDK Corporation
InventorsYoshitaka Murakawa, Hiroyuki Morita, Masanori Ikeda, Shogo Muroya, Tomokazu Ishikura
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Abstract
A ferrite sintered magnet 100 comprises 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. The ferrite sintered magnet 100 contains at least Fe, Ca, B, and Si, and contains 0.005 to 0.9 mass % of B in terms of B2O3. The multiple-crystal grain boundaries 6b contain Si and Ca, and in a case where the molar ratio of Ca to Si in the multiple-crystal grain boundaries 6b is represented by (Ca/Si)G, the following formula is satisfied. 0.1<(Ca/Si)G<0.9
Claims16
A ferrite sintered magnet comprising:
- M-type ferrite crystal grains;
- and
- multiple-crystal grain boundaries surrounded by three or more of the M-type ferrite crystal grains,
- wherein the ferrite sintered magnet contains at least Fe, Ca, B, and Si,
- the ferrite sintered magnet contains 0.005 to 0.9 mass % of B in terms of B2O3,
- the multiple-crystal grain boundaries contain Si and Ca, and
- in a case where the molar ratio of Ca to Si in the multiple-crystal grain boundaries is represented by (Ca/Si)G, the following formula is satisfied.
- 0.1<(Ca/Si)G<0.9
Dependencies are inferred from the claim text.