Ferrite sintered magnet, ferrite particle, bonded magnet and rotating electric machine

Patent metadata

Field	Value
Publication number	US-11688535-B2
Application number	US-202016825290-A
Country	US
Kind code	B2
Filing date	Mar 20, 2020
Priority date	Mar 27, 2019
Publication date	Jun 27, 2023
Grant date	Jun 27, 2023

Abstract

This ferrite sintered magnet comprises ferrite phases having a magnetoplumbite type crystal structure. This magnet comprises an element R, an element M, Fe, Co, B, Mn and Cr, the element R is at least one element selected from rare earth elements including Y, the element M is at least one element selected from the group consisting of Ca, Sr and Ba, with Ca being an essential element, and when an atomic composition of metallic elements is represented by R1-xMxFem-yCoy, x, y and m satisfy formulae:0.2≤x≤0.8  (1)0.1≤y≤0.65  (2)3≤m<14  (3).Additionally, a content of B is 0.1 to 0.4% by mass in terms of B2O3, a content of Mn is 0.15 to 1.02% by mass in terms of MnO, and a content of Cr is 0.02 to 2.01% by mass in terms of Cr2O3.

First claim

What is claimed is:

1. A ferrite sintered magnet comprising ferrite phases having a magnetoplumbite type crystal structure,
wherein the ferrite sintered magnet comprises an element R, an element M, Fe, Co, B, Mn and Cr,
the element R is at least one element selected from rare earth elements including Y,
the element M is at least one element selected from the group consisting of Ca, Sr and Ba, with Ca being an essential element,
when an atomic composition of metallic elements is represented by R 1-x M x Fe m-y Co y , x, y and m satisfy formulae (1), (2) and (3):
0.2≤ x≤ 0.8  (1)

0.1≤ y≤ 0.65  (2)

3≤ m< 14  (3),

a content of B is 0.1 to 0.4% by mass in terms of B 2 O 3 ,
a content of Mn is 0.15 to 1.02% by mass in terms of MnO, and
a content of Cr is 0.02 to 2.01% by mass in terms of Cr 2 O 3 .

2. The ferrite sintered magnet according to claim 1 , wherein the ferrite sintered magnet satisfies formulae (4) and (5):
0.2≤ x< 0.55  (4)

7.5< m< 14  (5).

3. A rotating electric machine comprising the ferrite sintered magnet according to claim 1 .

4. Ferrite particles comprising ferrite phases having a magnetoplumbite type crystal structure,
wherein the ferrite particles comprise an element R, an element M, Fe, Co, B, Mn and Cr,
the element R is at least one element selected from rare earth elements including Y,
the element M is at least one element selected from the group consisting of Ca, Sr and Ba, with Ca being an essential element,
when an atomic composition of metallic elements is represented by R 1-x M x Fe m-y Co y ,
x, y and m satisfy formulae (1), (2) and (3):
0.2≤ x≤ 0.8  (1)

0.1≤ y≤ 0.65  (2)

3≤ m< 14  (3),

a content of B is 0.1 to 0.4% by mass in terms of B 2 O 3 ,
a content of Mn is 0.15 to 1.02% by mass in terms of MnO, and
a content of Cr is 0.02 to 2.01% by mass in terms of Cr 2 O 3 .

5. The ferrite particles according to claim 4 , wherein the ferrite particles satisfy formulae (4) and (5):
0.2≤ x< 0.55  (4)

7.5< m< 14  (5).

6. A bonded magnet comprising ferrite particles, the ferrite particles comprising ferrite phases having a magnetoplumbite type crystal structure,
wherein the ferrite particles comprise an element R, an element M, Fe, Co, B, Mn and Cr,
the element R is at least one element selected from rare earth elements including Y,
the element M is at least one element selected from the group consisting of Ca, Sr and Ba, with Ca being an essential element,
when an atomic composition of metallic elements is represented by R 1-x M x Fe m-y Co y ,
x, y and m satisfy formulae (1), (2) and (3):
0.2≤ x≤ 0.8  (1)

0.1≤ y≤ 0.65  (2)

3≤ m< 14  (3),

a content of B is 0.1 to 0.4% by mass in terms of B 2 O 3 ,
a content of Mn is 0.15 to 1.02% by mass in terms of MnO, and
a content of Cr is 0.02 to 2.01% by mass in terms of Cr 2 O 3 .

7. A rotating electric machine comprising the bonded magnet according to claim 6 .

Assignees

• Tdk Corp

Inventors

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

Classifications

• C04B2235/3241

  Chromium oxides, chromates, or oxide-forming salts thereof · CPC title

• C04B35/2608

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

• H01F1/113 Primary

  in a bonding agent · CPC title

• C04B2235/3262

  Manganese oxides, manganates, rhenium oxides or oxide-forming salts thereof, e.g. MnO · CPC title

• C04B2235/3409

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