R-T-B based sintered magnet

Patent metadata

Field	Value
Publication number	US-10847290-B2
Application number	US-201414911597-A
Country	US
Kind code	B2
Filing date	Aug 11, 2014
Priority date	Aug 12, 2013
Publication date	Nov 24, 2020
Grant date	Nov 24, 2020

Abstract

To provide an R-T-B based sintered magnet having high Br and high HcJ while suppressing the content of Dy. Disclosed is an R-T-B based sintered magnet represented by the formula: uRwBxGayCuzAlqM(balance)T, where R is composed of light rare-earth element(s) RL and heavy rare-earth element(s) RH, RL is Nd and/or Pr, RH is Dy and/or Tb, T is Fe, and 10% by mass or less of Fe is capable of being replaced with Co, M is Nb and/or Zr, inevitable impurities being included, and u, w, x, y, z and q are expressed in terms of % by mass; RH accounts for 5% by mass or less of the R-T-B based sintered magnet, 0.4≤x≤1.0, 0.07≤y≤1.0, 0.05≤z≤0.5, 0≤q≤0.1, and 0.100≤y/(x+y)≤0.340; v=u−(6α+10β+8γ), where the amount of oxygen (% by mass) is α, the amount of nitrogen (% by mass) is β, and the amount of carbon (% by mass) is γ; and v and w satisfy the following inequality expressions: v≤32.0, 0.84≤w≤0.93, and −12.5w+38.75≤v≤−62.5w+86.125.

First claim

The invention claimed is:

1. An R-T-B based sintered magnet represented by the following formula (1):
u R w B x Ga y Cu z Al q M(100- u - w - x - y - z - q )T  (1)

wherein R is composed of light rare-earth element(s) RL and optionally heavy rare-earth element(s) RH, RL is Nd and/or Pr, RH is Dy and/or Tb, T as balance is Fe, and 10% by mass or less of Fe being replaced with Co, M is Nb and/or Zr, and u, w, x, y, z, q and 100-u-w-x-y-z-q are expressed in terms of % by mass;
said RH accounts for 5% by mass or less of the R-T-B based sintered magnet, the following inequality expressions (2) to (6) being satisfied:
0.4≤ x≤ 1.0  (2)

0.07≤ y≤ 1.0  (3)

0.05≤ z≤ 0.5  (4)

0≤ q≤ 0.1  (5)

0.100≤ y /( x+y )≤0.340  (6)

v=u−(6α+10β+8γ), wherein the amount of oxygen (% by mass) of the R-T-B based sintered magnet is α, the amount of nitrogen (% by mass) is β, and the amount of carbon (% by mass) is γ; and
v and w satisfy the following inequality expressions (7) to (9):
v≤ 29.5  (7)

0.89≤ w≤ 0.93  (8)

−12.5 w+ 38.75≤ v≤− 62.5 w+ 86.125  (9).

2. The R-T-B based sintered magnet according to claim 1 , satisfying the following inequality expressions (10) and (11):
0.4≤ x≤ 0.7  (10)

0.1≤ y≤ 0.7  (11).

3. The R-T-B based sintered magnet according to claim 1 , satisfying the following inequality expression (12):
0.4≤ x≤ 0.6  (12).

4. The R-T-B based sintered magnet according to claim 1 , satisfying the following inequality expression (13):
v≤ 28.5  (13).

5. The R-T-B based sintered magnet according to claim 1 , satisfying the following inequality expression (14):
0.90≤ w≤ 0.93  (14).

6. The R-T-B based sintered magnet according to claim 1 , satisfying the following inequality expression (15):
0.1≤ y≤ 0.361  (15).

7. The R-T-B based sintered magnet according to claim 2 , satisfying the following inequality expression (16):
0.1≤ y≤ 0.30  (16).

Assignees

• Hitachi Metals Ltd

Inventors

• Nishiuchi Takeshi
• Kanda Takayuki
• Ishii Rintaro
• Kuniyoshi Futoshi
• Satoh Teppei

Classifications

• C22C33/02

  by powder metallurgy · CPC title

• C22C38/00

  Ferrous alloys, e.g. steel alloys (cast-iron alloys C22C37/00) · CPC title

• C22C2202/02

  Magnetic · CPC title

• C22C30/02

  containing copper · CPC title

• H01F1/0577 Primary

  sintered · CPC title