Granted Patent B2

US 12,488,918 · App. 17/785,044 · Granted Dec 2, 2025

Inventors: Ying Luo (Fujian, CN); Jiaying Huang (Fujian, CN); Zongbo Liao (Fujian, CN); Qin Lan (Fujian, CN); Yulin Lin (Fujian, CN); Dawei Shi (Fujian, CN); Juhua Xie (Fujian, CN); Yanqing Long (Fujian, CN)

Assignee: FUJIAN GOLDEN DRAGON RARE-EARTH Co., Ltd.

H01F1/0577B22F3/1017B22F9/04B22F2009/044B22F2203/11B22F2302/05B22F2303/01

Abstract

Claims (102)

1 . A neodymium-iron-boron magnet material, which comprises the following components by mass percentage:

R: 28-33%; R comprises R1 and R2, R1 comprises Nd and Dy, R2 comprises Tb, the content of R2 is 0.2%-1%; the content of Dy in R1 is 0.05-0.3%;

Co: 0.05-0.45%;

M: ≤0.4%, but not 0, M is at least one element selected from group consisting of Bi, Sn, Zn, Ga, In, Au, and Pb;

Cu: ≤0.15%, but not 0;

B: 0.9-1.1%;

Fe: 60-70%;

C; and

O;

the percentage is the mass percentage of the mass of each component to the total mass of neodymium-iron-boron magnet material;

the neodymium-iron-boron magnet material comprises Nd 2 Fe 14 B grains and their shells, and two-grain intergranular boundary and grain boundary triangle region adjoining to the Nd 2 Fe 14 B grains; wherein, heavy rare earth elements in R1 are distributed in Nd 2 Fe 14 B grains, R2 is mainly distributed in the shell, two-grain intergranular boundary and grain boundary triangle region, the area proportion of the grain boundary triangle region is 1.9-3.15%; the continuity of the two-grain intergranular boundary is 96% or more; the proportion of the mass of C and O in the grain boundary triangle region is 0.4-0.5%, the proportion of the mass of C and O in the two-grain intergranular boundary is 0.3-0.45%; wherein, the continuity of two-grain intergranular boundary refers to the ratio of the length of a B rich phase, a rare earth rich phase, rare earth oxides and rare earth carbides in the grain boundary to the total length of the grain boundary;

the two-grain intergranular boundary further comprises a new phase with the chemical composition of R x (Fe+Co) 100-x-y-z Cu y M z ; wherein, R in the R x (Fe+Co) 100-x-y-z Cu y M z comprises at least one element selected from Nd, Dy, and Tb; M is at least one element selected from Bi, Sn, Zn, Ga, In, Au, and Pb; x is 42-44; y is 0.2-0.4; z is 0.2-0.45.

2 . The neodymium-iron-boron magnet material according to claim 1 , wherein, the neodymium-iron-boron magnet material satisfies any one of the following schemes:

scheme 1 :

the content of R is 29.5-32.6%; R1 is rare earth element added during smelting;

R2 is rare earth element added during grain boundary diffusion, the content of R2 is 0.2%-0.9%;

the content of M is 0.35% or less, but not 0, M is at least one element selected from group consisting of Ga, Bi, and Zn;

the content of Cu is 0.05-0.15%;

the content of B is 0.97-1.05%;

the content of Fe is 65-69.5%;

the area proportion of the grain boundary triangle region is 1.98-2.78%;

the continuity of the two-grain intergranular boundary is 97% or more;

the mass proportion of C and O in the grain boundary triangle region is 0.41-0.49%, the mass proportion of C and O in the two-grain intergranular boundary is 0.32-0.41%;

in the new phase with the chemical composition of R x (Fe+Co) 100-x-y-z Cu y M z ; wherein, R in the R x (Fe+Co) 100-x-y-z Cu y M z comprises at least one element selected from Nd, Dy and Tb; M is at least one element selected from group consisting of Ga, Bi, and Zn; x is 42-44; y is 0.2-0.4; z is 0.2-0.45; the ratio of the area of the new phase in the two-grain intergranular boundary to total area of the two-grain intergranular boundary is 0.24-2.2%;

scheme 2 :

the content of R is 29.5-30.5; R1 is rare earth element added during smelting;

R2 is rare earth element added during grain boundary diffusion, the content of R2 is 0.2%-0.8%;

the content of Co is 0.1%-0.4%;

the content of M is 0.05%-0.35%, M is at least one element selected from group consisting of Ga, Bi, and Zn;

the content of Cu is 0.05-0.08%;

the content of B is 0.99-1.1%;

the content of Fe is 65.5-69%;

the area proportion of the grain boundary triangle region is 1.98-2.62%;

the continuity of grain boundary of the neodymium-iron-boron magnet material is 98% or more;

the mass proportion of C and O in the grain boundary triangle region is 0.41-0.45%, the mass proportion of C and O in the two-grain intergranular boundary is 0.34-0.41%;

in the new phase with the chemical composition of R x (Fe+Co) 100-x-y-z Cu y M z ; wherein, R in the R x (Fe+Co) 100-x-y-z Cu y M z comprises at least one element selected from group consisting of Nd, Dy, and Tb; M is at least one element selected from group consisting of Ga, Bi, and Zn; x is 42.33-43.57; y is 0.23-0.35; z is 0.27-0.41; the ratio of the area of the new phase in the two-grain intergranular boundary to total area of the two-grain intergranular boundary is 0.5-2.14%.

3 . A magnet steel, which is prepared using the neodymium-iron-boron magnet material according to claim 1 .

4 . The neodymium-iron-boron magnet material according to claim 1 , wherein, x is 42.33-43.57, y is 0.23-0.35, z is 0.27-0.41;

or, the ratio of the area of the new phase in the two-grain intergranular boundary to the total area of the two-grain intergranular boundary is 0.24-2.2%.

5 . The neodymium-iron-boron magnet material according to claim 1 , wherein, the content of Nd in R1 is 28.5-32.5%;

or, R1 further comprises at least one element selected from the group consisting of Pr, Ho, Tb, Gd, and Y;

or, R2 further comprises at least one element selected from the group consisting of Pr and Dy;

or, Cu has been added to the material during smelting or during grain boundary diffusion.

6 . The neodymium-iron-boron magnet material according to claim 5 , wherein, when R2 comprises Pr, the content of Pr is 0.2% or less, but not 0;

or, when R2 comprises Dy, the content of Dy is 0.3% or less, but not 0.

7 . The neodymium-iron-boron magnet material according to claim 1 , wherein, M is at least one element selected from the group consisting of Zn, Ga, and Bi;

or, the neodymium-iron-boron magnet material further comprises Al.

8 . The neodymium-iron-boron magnet material according to claim 7 , wherein, the content of Al is 0.3% or less, but not 0.

9 . A preparation method for the neodymium-iron-boron magnet material according to claim 1 , which employs a raw material composition; the preparation method comprises the following steps: elements other than R2 in the raw material composition of neodymium-iron-boron magnet material are subjected to

smelting,

powdering,

forming,

sintering to obtain a sinter,

and then the mixture of the sinter and R2 is subjected to grain boundary diffusion;

operations of the smelting are that elements other than R2 of the raw material composition of neodymium-iron-boron magnet material are smelted and casted by ingot casting process and strip-casting flake process to obtain alloy sheets;

the raw material composition comprises the following components by mass percentage: R: 28-33%;

R is rare earth element, which comprises R1 and R2;

R1 is rare earth element added during smelting, which comprises Nd and Dy;

R2 is rare earth element added during grain boundary diffusion, which comprises Tb, the content of R2 is 0.2%-1%;

Co: 0.05-0.45%;

M≤0.4%, but not 0, M is at least one element selected from the group consisting of Bi, Sn, Zn, Ga, In, Au, and Pb;

Cu≤0.15%, but not 0;

B: 0.9-1.1%;

Fe: 60-70%;

the percentage is the mass percentage of the mass of each component to the total mass of the raw material composition.

10 . The preparation method according to claim 9 , wherein, the raw material composition satisfies any one of the following schemes:

scheme 1 :

the content of R is 29.5-32.6%;

the content of R2 is 0.2%-0.9%;

the content of Co is 0.05-0.45%;

the content of M is 0.35% or less, but not 0, M is at least one element selected from the group consisting of Ga, Bi, and Zn;

the content of Cu is 0.05-0.15%;

the content of B is 0.97-1.1%;

the content of Fe is 65-69.5%;

scheme 2 :

the content of R is 29.5-30.5%;

the content of R2 is 0.2%-0.8%;

the content of Co is 0.1-0.4%;

the content of M is 0.05-0.35%, M is at least one element selected from the group consisting of Ga, Bi, and Zn;

the content of Cu is 0.05-0.08%;

the content of B is 0.99-1.1%;

the content of Fe is 65.5-69%.

11 . The preparation method according to claim 9 , wherein, in the raw material composition,

the content of Nd in R1 of the raw material composition is 28.5-32.5%;

or, the content of Dy in R1 is 0.3% or less, but not 0;

or, R1 further comprises one or more of Pr, Ho, Tb, Gd, and Y;

or, R2 further comprises at least one element selected from the group consisting of Pr and Dy;

or, the way of adding Cu comprises adding Cu during smelting or adding Cu during grain boundary diffusion.

12 . The preparation method according to claim 9 , wherein, in the raw material composition,

M is at least one element selected from the group consisting of Zn, Ga, and Bi;

or, the raw material composition further comprises Al.

13 . The preparation method according to claim 12 , wherein, in the raw material composition,

the content of Al is 0.3% or less, but not 0.

14 . The preparation method according to claim 9 , wherein, after the grain boundary diffusion, the low temperature tempering treatment is further performed.

15 . The preparation method according to claim 14 , wherein, the temperature of the smelting is 1300-1700° C.;

the powdering process comprises hydrogen decrepitation powdering and jet milling powdering; the hydrogen decrepitation powdering comprises hydrogen absorption, dehydrogenation and cooling treatment; the temperature of the hydrogen absorption is 20-200° C., the temperature of the dehydrogenation is 400-650° C., the pressure of the hydrogen absorption is 50-600 kPa; the jet milling powdering is performed under the condition of 0.1-2 MPa, the time of the jet milling powdering is 2-4 h;

the temperature of the sintering is 1000-1200° C.;

the time of the sintering is 0.5-10 h;

the temperature of the grain boundary diffusion is 800-1000° C.;

the time of the grain boundary diffusion is 5-20 h;

the temperature of the low temperature tempering treatment is 460-560° C.; and,

the time of the low temperature tempering treatment is 1-3 h.

Assignments (2)

Priority Claims (1)

Continuity (1)

References Cited (20)