Ferrite sintered magnet and rotating electric machine

Patent metadata

Field	Value
Publication number	US-11664142-B2
Application number	US-202117201809-A
Country	US
Kind code	B2
Filing date	Mar 15, 2021
Priority date	Mar 30, 2020
Publication date	May 30, 2023
Grant date	May 30, 2023

Abstract

To provide a ferrite sintered magnet having a high residual magnetic flux density (Br), a high coercive force (HcJ), a good production stability, 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 A 1-x R x (Fe 12-y Co y ) z O 19 . 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. 0.14≤x≤0.22, 11.60≤(12-y)z≤11.99, and 0.13≤yz≤0.17 are satisfied. 0.30≤Mc≤0.63 is satisfied in which Mc is CaO content (mass %) converted from a content of Ca included in the ferrite sintered magnet.

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;
0.14≤x≤0.20,
11.60≤(12-y)z≤11.99, and
0.13≤yz≤0.17 are satisfied;
0.30≤Mc≤0.63 is satisfied in which Mc is CaO content (mass %) converted from a content of Ca included in the ferrite sintered magnet,
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,
0.03≤Mb≤0.12 is satisfied in which Mb is BaO content (mass %) converted from a content of Ba included in the ferrite sintered magnet,
0.05≤Ma≤0.90 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
0.05≤Mr≤0.08 is satisfied in which Mr is Cr 2 O 3 content (mass %) converted from a content of Cr included in the ferrite sintered magnet.

2. The ferrite sintered magnet according to claim 1 , wherein 0.14≤x≤0.19 is satisfied.

3. 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

• C04B2235/3241

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

• H01F1/10

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

• C01P2002/76

  by a space-group or by other symmetry indications · CPC title

• C04B35/2633

  containing barium, strontium or calcium · CPC title

• C04B2235/767

  Hexagonal symmetry, e.g. beta-Si3N4, beta-Sialon, alpha-SiC or hexa-ferrites · CPC title