Ferrite sintered magnet and rotating electric machine

Patent metadata

Field	Value
Publication number	US-11636964-B2
Application number	US-202117198517-A
Country	US
Kind code	B2
Filing date	Mar 11, 2021
Priority date	Mar 30, 2020
Publication date	Apr 25, 2023
Grant date	Apr 25, 2023

Abstract

To provide a ferrite sintered magnet having a high residual magnetic flux density (Br) and a high coercive force (HcJ), and also able to produce at a low cost. The ferrite sintered magnet includes a hexagonal M-type ferrite including A, R, Fe, and Co in an atomic ratio of A1-xRx(Fe12-yCoy)zO19. A is at least one selected from Sr, Ba, and Pb. R is La only or La and at least one selected from rare earth elements. 0.13≤x≤0.23, 10.80≤(12−y)z≤12.10, and 0.13≤yz≤0.20 are satisfied.

First claim

What is claimed is:

1. A ferrite sintered magnet comprising a hexagonal M-type ferrite including A, R, Fe, and Co in an atomic ratio of A 1-x R x (Fe 12-y Co y ) z O 19 , wherein
A is at least one selected from Sr, Ba, and Pb,
R is La only or La and at least one selected from rare earth elements, and
0.13≤ x≤ 0.23,

10.80≤(12− y ) z≤ 12.10, and

0.13< yz< 0.20 are satisfied,

0.05≤Ma≤0.70 is satisfied in which Ma is Al 2 O 3 content (mass %) converted from a content of Al included in the ferrite sintered magnet, and
0.30<Mc<0.85 is satisfied in which Mc is CaO content (mass %) converted from a content of Ca included in the ferrite sintered magnet.

2. The ferrite sintered magnet according to claim 1 , wherein 0.35≤Ms≤0.60 is satisfied in which Ms is SiO 2 content (mass %) converted from a content of Si included in the ferrite sintered magnet.

3. The ferrite sintered magnet according to claim 1 , wherein 0≤Mb≤0.15 is satisfied in which Mb is BaO content (mass %) converted from a content of Ba included in the ferrite sintered magnet.

4. The ferrite sintered magnet according to claim 1 , wherein 0.03≤Mb≤0.15 is satisfied in which Mb is BaO content (mass %) converted from a content of B a included in the ferrite sintered magnet.

5. The ferrite sintered magnet according to claim 1 , wherein 0≤Mr≤0.10 is satisfied in which Mr is Cr 2 O 3 content (mass %) converted from a content of Cr included in the ferrite sintered magnet.

6. The ferrite sintered magnet according to claim 1 , wherein 0.05≤Mr≤0.09 is satisfied in which Mr is Cr 2 O 3 content (mass %) converted from a content of Cr included in the ferrite sintered magnet.

7. A rotating electric machine including the ferrite sintered magnet according to claim 1 .

Assignees

• Tdk Corp

Inventors

• Muroya Shogo
• Murakawa Yoshitaka
• Morita Hiroyuki
• Ikeda Masanori

Classifications

• C01P2002/52

  containing elements as dopants · CPC title

• C04B2235/3208

  Calcium oxide or oxide-forming salts thereof, e.g. lime · CPC title

• H01F1/11 Primary

  in the form of particles {(for magnetic record carriers G11B5/70626)} · CPC title

• C04B2235/3418

  Silicon oxide, silicic acids or oxide forming salts thereof, e.g. silica sol, fused silica, silica fume, cristobalite, quartz or flint · CPC title

• H01F1/10

  non-metallic substances, e.g. ferrites {, e.g. [(Ba,Sr)O(Fe2O3)6] ferrites with hexagonal structure} · CPC title