Highly thermostable rare-earth permanent magnetic material, preparation method thereof and magnet containing the same

Patent metadata

Field	Value
Publication number	US-11101057-B2
Application number	US-201815868063-A
Country	US
Kind code	B2
Filing date	Jan 11, 2018
Priority date	Mar 17, 2017
Publication date	Aug 24, 2021
Grant date	Aug 24, 2021

Abstract

Provided are a highly thermostable rare-earth permanent magnetic material, a preparation method thereof and a magnet containing the same. A composition of the rare-earth permanent magnetic material by an atomic percentage is as follows: SmxRaFe100-x-y-z-aMyNz, wherein R is at least one of Zr and Hf, M is at least one of Co, Ti, Nb, Cr, V, Mo, Si, Ga, Ni, Mn and Al, x+a is 7-10%, a is 0-1.5%, y is 0-5% and z is 10-14%.

First claim

What is claimed is:

1. A rare-earth permanent magnetic material, a composition of the rare-earth permanent magnetic material by an atomic percentage being as follows:
Sm x R a Fe 100-x-y-z-a M y N z
wherein R is at least one of Zr and Hf, M is at least one of Cr, V, Mo, Ni, and Mn, 7%≤x+a≤10%, 0<a≤1.5%, 0<y≤5%, 10%≤z≤14%, wherein the rare-earth permanent magnetic material comprises a TbCu 7 phase, a Th 2 Zn 17 phase and a soft magnetic phase α-Fe, wherein a content of the TbCu7 phase in the rare-earth permanent magnetic material is 80% or more, and a content of the soft magnetic phase α-Fe in the rare-earth permanent magnetic material is 0-5%, excluding 0, wherein the magnetic property Hcj of the rare-earth permanent magnetic material is 10 kOe or more and the magnetic energy product Bh is 14 MGOe or more.

2. A preparation method of the rare-earth permanent magnetic material as claimed in claim 1 , comprising the following steps:
(1) performing master alloy melting on Sm, R, Fe, and M;
(2) quick-quenching a master alloy obtained in the step (1) to prepare a quick-quenched ribbon;
(3) performing a crystallization treatment on the quick-quenched ribbon obtained in the step (2); and
(4) nitriding a permanent magnetic material crystallized in the step (3) to obtain the rare-earth permanent magnetic material, wherein the performing the crystallization treatment on the quick-quenched ribbon obtained in the step (2) comprises: wrapping the quick-quenched ribbon, then performing a heat treatment and then a quenching treatment, wherein the quenching treatment employing a water-cooling manner in an argon atmosphere, and wherein the heat treatment is performed in a tubular resistance furnace and in an argon atmosphere.

3. The preparation method as claimed in claim 2 , wherein the melting in the step (1) is performed by means of an electric arc; and an ingot obtained by the melting is preliminarily crushed into millimeter-level ingot blocks.

4. The preparation method as claimed in claim 2 , wherein the quick-quenching in the step (2) is as follows:
putting the master alloy into a quartz tube having a nozzle; and
melting into an alloy liquid via induction melting, and spraying to a rotary water-cooling copper mould via the nozzle to obtain the quick-quenched ribbon; and a wheel speed in the quick-quenching is 20-80 m/s.

5. The preparation method as claimed in claim 2 , wherein the nitriding in the step (4) is performed in a nitriding furnace.

6. A magnet, comprising the rare-earth permanent magnetic material as claimed in claim 1 , wherein the irreversible flux loss of a magnet prepared from the rare-earth permanent magnetic material is less than 5% when exposing for 2 h in the air at 120° C.

7. The magnet as claimed in claim 6 , wherein the magnet is formed by bonding the rare-earth permanent magnetic material and an adhesive, the magnet prepared with the following method: mixing the rare-earth permanent magnetic material with an epoxy resin to obtain a mixture, adding a lubricant to the mixture, then performing a treatment to obtain a bonded magnet, and at last thermocuring the bonded magnet.

8. The magnet as claimed in claim 7 , wherein a proportion of the rare-earth permanent magnetic material to the epoxy resin by weight is 100:1-10.

9. The preparation method as claimed in claim 3 , wherein the quick-quenching in the step (2) is as follows: putting the master alloy into a quartz tube having a nozzle, melting into an alloy liquid via induction melting, and spraying to a rotary water-cooling copper mould via the nozzle to obtain the quick-quenched ribbon.

10. The rare-earth permanent magnetic material as claimed in claim 1 , wherein the rare-earth permanent magnetic material is composed of crystal grains having an average size of 10 nm to 1 μm.

11. The preparation method as claimed in claim 2 , wherein a temperature of the heat treatment is 700-900° C. and a time is 5 min or more.

12. The preparation method as claimed in claim 5 , wherein the nitriding is performed in a high-purity nitrogen atmosphere at 1-2 atm.

13. The preparation method as claimed in claim 5 , wherein a temperature of the nitriding is 350-600° C. and a time is for 12 h or more.

14. The magnet as claimed in claim 8 , wherein an added amount of the lubricant is 0.2-1 wt %.

Assignees

• Grirem Advanced Mat Co Ltd

Inventors

• Wu Guiyong
• Luo Yang
• Li Hongwei
• Yang Yuanfei
• Yu Dunbo
• Quan Ningtao
• Yuan Chao
• Yan Wenlong

Classifications

• B22F1/10

  Metallic powder containing lubricating or binding agents; Metallic powder containing organic material · CPC title

• B22F1/145

  Chemical treatment, e.g. passivation or decarburisation · CPC title

• B22F1/142

  Thermal or thermo-mechanical treatment · CPC title

• B22F2009/0812

  Pulverisation with a moving liquid coolant stream, by centrifugally rotating stream · CPC title

• H01F1/083

  in a bonding agent · CPC title