Ferrite sintered magnet, motor and generator

Patent metadata

Field	Value
Publication number	US-11205533-B2
Application number	US-201916282466-A
Country	US
Kind code	B2
Filing date	Feb 22, 2019
Priority date	Feb 26, 2018
Publication date	Dec 21, 2021
Grant date	Dec 21, 2021

Abstract

A ferrite sintered magnet contains a main phase formed of ferrite having a hexagonal magnetoplumbite type crystalline structure; a first subphase containing La, Ca, and Fe, in which an atomic ratio of La is higher than that of the main phase, and the atomic ratio of La is higher than an atomic ratio of Ca; and a second subphase containing La, Ca, Si, B, and Fe, in which an atomic ratio of Ca is higher than an atomic ratio of La, an atomic ratio of B is higher than an atomic ratio of Fe, and the atomic ratio of Fe is lower than that of the main phase. An area ratio of the second subphase on a cross-sectional surface of the ferrite sintered magnet is greater than or equal to 1%.

First claim

What is claimed is:

1. A ferrite sintered magnet, comprising:
a main phase formed of ferrite having a hexagonal magnetoplumbite crystalline structure;
a first subphase containing La, Ca, and Fe, in which an atomic ratio of La is higher than that of the main phase, and the atomic ratio of La is higher than an atomic ratio of Ca; and
a second subphase containing La, Ca, Si, B, and Fe, in which an atomic ratio of Ca is higher than an atomic ratio of La, an atomic ratio of B is higher than an atomic ratio of Fe, and the atomic ratio of Fe is lower than that of the main phase,
wherein an area ratio of the second subphase on a cross-sectional surface, is greater than or equal to 9.9%, and
wherein the area ratio of the second subphase is larger than an area ratio of the first subphase, on the cross-sectional surface.

2. The ferrite sintered magnet according to claim 1 ,
wherein in the second subphase, when a total of La, Ca, Si, B, and Fe is set to 100 atom %, a ratio of La is 1 atom % to 25 atom %, a ratio of Ca is 30 atom % to 70 atom %, a ratio of Si is less than or equal to 50 atom %, a ratio of B is 8 atom % to 60 atom %, and a ratio of Fe is less than or equal to 20 atom %.

3. The ferrite sintered magnet according to claim 1 , wherein the area ratio of the first subphase on the cross-sectional surface is less than or equal to 5%.

4. The ferrite sintered magnet according to claim 1 , wherein the ferrite sintered magnet contains CaB 2 O 4 .

5. The ferrite sintered magnet according to claim 2 , wherein the ferrite sintered magnet contains CaB 2 O 4 .

6. The ferrite sintered magnet according to claim 3 , wherein the ferrite sintered magnet contains CaB 2 O 4 .

7. The ferrite sintered magnet according to claim 4 , wherein the second subphase contains CaB 2 O 4 .

8. The ferrite sintered magnet according to claim 5 , wherein the second subphase contains CaB 2 O 4 .

9. The ferrite sintered magnet according to claim 6 , wherein the second subphase contains CaB 2 O 4 .

10. The ferrite sintered magnet according to claim 4 , wherein an area ratio of CaB 2 O 4 contained in the second subphase, is less than or equal to 2%, on the cross-sectional surface.

11. The ferrite sintered magnet according to claim 5 , wherein an area ratio of CaB 2 O 4 contained in the second subphase, is less than or equal to 2%, on the cross-sectional surface.

12. The ferrite sintered magnet according to claim 6 , wherein an area ratio of CaB 2 O 4 contained in the second subphase, is less than or equal to 2%, on the cross-sectional surface.

13. A motor comprising:
the ferrite sintered magnet according to claim 1 .

14. A generator comprising:
the ferrite sintered magnet according to claim 1 .

15. A ferrite sintered magnet, comprising:
a main phase formed of ferrite having a hexagonal magnetoplumbite crystalline structure;
a first subphase containing La, Ca, and Fe, in which an atomic ratio of La is higher than that of the main phase, and the atomic ratio of La is higher than an atomic ratio of Ca; and
a second subphase containing La, Ca, Si, B, and Fe, in which an atomic ratio of Ca is higher than an atomic ratio of La, an atomic ratio of B is higher than an atomic ratio of Fe, and the atomic ratio of Fe is lower than that of the main phase,
wherein an area ratio of the second subphase on a cross-sectional surface, is greater than or equal to 1%, and
wherein in the second subphase, when a total of La, Ca, Si, B, and Fe is set to 100 atom %, a ratio of La is1 atom % to 25 atom %, a ratio of Ca is 30 atom % to 70 atom %, a ratio of Si is less than or equal to 50 atom %, a ratio of B is 8 atom % to 60 atom %, and a ratio of Fe is less than or equal to 20 atom %.

16. The ferrite sintered magnet according to claim 15 , wherein the ferrite sintered magnet contains CaB 2 O 4 .

17. The ferrite sintered magnet according to claim 16 , wherein the second subphase contains CaB 2 O 4 .

18. The ferrite sintered magnet according to claim 16 , wherein an area ratio of CaB 2 O 4 contained in the second subphase, is less than or equal to 2%, on the cross-sectional surface.

19. The ferrite sintered magnet according to claim 15 , wherein the area ratio of the second subphase on the cross-sectional surface is greater than or equal to 9.9%.

20. A ferrite sintered magnet, comprising:
a main phase formed of ferrite having a hexagonal magnetoplumbite crystalline structure;
a first subphase containing La, Ca, and Fe, in which an atomic ratio of La is higher than that of the main phase, and the atomic ratio of La is higher than an atomic ratio of Ca; and
a second subphase containing La, Ca, Si, B, and Fe, in which an atomic ratio of Ca is higher than an atomic ratio of La, an atomic ratio of B is higher than an atomic ratio of Fe, and the atomic ratio of Fe is lower than that of the main phase,
wherein an area ratio of the second subphase on a cross-sectional surface, is greater than or equal to 1%,
wherein the area ratio of the second subphase is larger than an area ratio of the first subphase, on the cross-sectional surface,
wherein the ferrite sintered magnet contains CaB 2 O 4 , and
wherein an area ratio of CaB 2 O 4 contained in the second subphase, is less than or equal to 2%, on the cross-sectional surface.

Assignees

• Tdk Corp

Inventors

• Nagaoka Junnichi
• Ono Hiroyuki
• Sugawara Yuichi

Classifications

• H02K1/17

  Stator cores with permanent magnets · CPC title

• H01F3/08

  made from powder (powder coatings on sheets H01F3/02; on strips or ribbons H01F3/04; on wires H01F3/06) · CPC title

• H02K2213/03

  Machines characterised by numerical values, ranges, mathematical expressions or similar information · CPC title

• H02K1/02

  characterised by the magnetic material · 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