Ferrite sintered magnet, ferrite particles, bonded magnet, and rotating electrical machine

Patent metadata

Field	Value
Publication number	US-12243668-B2
Application number	US-202017598508-A
Country	US
Kind code	B2
Filing date	Mar 27, 2020
Priority date	Mar 29, 2019
Publication date	Mar 4, 2025
Grant date	Mar 4, 2025

Abstract

A ferrite sinter magnet has a ferrite phase having a magnetoplumbite-type crystal structure, and contains at least a metal element A, a metal element R, Fe, Co, Zn, and B. The element A is at least one kind of element selected from the group consisting of Sr, Ba, Ca, and Pb, and essentially includes Ca. the element R is at least one kind selected from the group consisting of Bi and rare-earth elements including Y, and essentially includes La. Atomic ratios of the metal elements satisfy the following Expressions (1) to (5),

A 1-r R e Fe x Co y Zn z   (1)

0.40≤ r ≤0.70  (2)

8.20≤ x ≤9.34  (3)

0.05≤ y ≤0.50  (4)

0< z ≤0.20  (5)

The content of Si is 0 to 0.60% by mass in terms of SiO 2 , and the content of B is 0.1-0.70% by mass in terms of B 2 O 3 .

First claim

The invention claimed is:

1. A ferrite sintered magnet having a ferrite phase having a magnetoplumbite-type crystal structure, containing:
at least a metal element A, a metal element R, Fe, Co, Zn, and B,
wherein the metal element A is at least one kind of element selected from the group consisting of Sr, Ba, Ca, and Pb, and essentially includes Ca,
the metal R is at least one kind selected from the group consisting of Bi and rare earth elements including Y, and essentially includes La,
when an atomic ratio of the metal elements is expressed by Formula (1),
r, x, y, and z satisfy the following Expressions (2) to (5),
A 1-r R e Fe x Co y Zn z   (1)

0.40≤ r≤ 0.70  (2)

8.20≤ x≤ 9.34  (3)

0.05≤ y≤ 0.50  (4)

0.01≤ z≤ 0.10  (5)

a content of Si is 0-0.60% by mass in terms of SiO 2 ,
the content of B is 0.1-0.70% by mass in terms of B 2 O 3 , and
a coercive force HcJ of the ferrite sintered magnet is 4000 Oe or more.

2. The ferrite sintered magnet according to claim 1 ,
wherein the content of Si is 0.01 to 0.40% by mass in terms of SiO 2 , and the content of B is 0.20 to 0.70% by mass in terms of B 2 O 3 .

3. The ferrite sintered magnet according to claim 1 ,
wherein Ca occupies 95 atomic % or more of the metal element A.

4. A rotating electrical machine comprising:
the ferrite sintered magnet according to claim 1 .

5. Ferrite particles having a ferrite phase having a magnetoplumbite-type crystal structure, containing:
at least a metal element A, a metal element R, Fe, Co, Zn, and B,
wherein the metal element A is at least one kind of element selected from the group consisting of Sr, Ba, Ca, and Pb, and essentially includes Ca,
the metal R is at least one kind selected from the group consisting of Bi and rare-earth elements including Y, and essentially includes La,
when an atomic ratio of the metal elements is expressed by Formula (1),
r, x, y, and z satisfy the following Expressions (2) to (5),
A 1-r R e Fe x Co y Zn z   (1)

0.40≤ r≤ 0.70  (2)

8.20≤ x≤ 9.34  (3)

0.05≤ y≤ 0.50  (4)

0.01≤ z≤ 0.10  (5)

a content of Si is 0-0.60% by mass in terms of SiO 2 ,
the content of B is 0.1-0.70% by mass in terms of B 2 O 3 , and
a coercive force HcJ of the ferrite particles in the form of a ferrite sintered magnet is 4000 Oe or more.

6. The ferrite particles according to claim 5 ,
wherein the content of Si is 0.01 to 0.40% by mass in terms of SiO 2 , and the content of B is 0.20 to 0.70% by mass in terms of B 2 O 3 .

7. The ferrite particles according to claim 5 ,
wherein Ca occupies 95 atomic % or more of the metal element A.

8. A bonded magnet containing:
the ferrite particles according to claim 5 .

9. A rotating electrical machine comprising:
the bonded magnet according to claim 8 .

Assignees

• Tdk Corp

Inventors

• Ohmura Masashi
• Nagaoka Junichi
• Muroya Shogo
• Abe Takuma
• Sato Jo

Classifications

• H01F1/113

  in a bonding agent · CPC title

• H01F1/10

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

• C04B2235/3409

  Boron oxide, borates, boric acids, or oxide forming salts thereof, e.g. borax · 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

• C04B35/2641

  Compositions containing one or more ferrites of the group comprising rare earth metals and one or more ferrites of the group comprising alkali metals, alkaline earth metals or lead · CPC title