阅读说明：本技术 一种高性能钕铁硼永磁材料及其制备方法 (High-performance neodymium iron boron permanent magnet material and preparation method thereof ) 是由 舒泽腾 郑波 郭帅 陈仁杰 丁广飞 闫阿儒 于 2020-05-08 设计创作，主要内容包括：一种高性能钕铁硼永磁材料及其制备方法。本发明提供了一种钕铁硼永磁材料,由如式(Nd,Pr)<Sub>x</Sub>Fe<Sub>(100-x-y-z)</Sub>B<Sub>y</Sub>M<Sub>z</Sub>所示的各向异性磁体和如式Tb<Sub>a</Sub>Fe<Sub>b</Sub>Al<Sub>100-a-b</Sub>所示的重稀土制备得到,所述重稀土占所述各向异性磁体和所述重稀土总量的质量比例为0.1～5wt％。本申请还提供了所述钕铁硼永磁材料的制备方法。本申请提供的钕铁硼永磁材料在降低重稀土元素使用量的基础上,可以保证钕铁硼磁体剩磁不降或者微降的情况下,钕铁硼磁体的矫顽力得到明显的提升,从而大幅降低生产成本。(A high-performance neodymium iron boron permanent magnet material and a preparation method thereof. The invention provides a neodymium iron boron permanent magnet material, which is prepared from the following components in formula (Nd, Pr) x Fe (100‑x‑y‑z) B y M z Shown anisotropic magnet and formula Tb a Fe b Al 100‑a‑b The heavy rare earth is prepared, and the mass ratio of the heavy rare earth to the total amount of the anisotropic magnet and the heavy rare earth is 0.1-5 wt%. The application also provides a preparation method of the neodymium iron boron permanent magnet material. On the basis of reducing the use amount of heavy rare earth elements, the neodymium iron boron permanent magnet material can ensure that the coercive force of the neodymium iron boron magnet is obviously improved under the condition that the residual magnetism of the neodymium iron boron magnet is not reduced or is slightly reduced, so that the production cost is greatly reduced.)

1. A neodymium iron boron permanent magnet material is prepared from an anisotropic magnet shown in a formula (I) and heavy rare earth shown in a formula (II), wherein the heavy rare earth accounts for 0.1-5 wt% of the total weight of the anisotropic magnet and the heavy rare earth;

(Nd,Pr)_xFe_(100-x-y-z)B_yM_z(Ⅰ)；

Tb_aFe_bAl_100-a-b(Ⅱ)；

wherein x is more than or equal to 28.6 wt% and less than or equal to 29.5 wt%, y is more than or equal to 0.85 wt% and less than or equal to 0.9 wt%, z is more than 0 and less than or equal to 2.5 wt%, and M is selected from one or more of Co, Al, Cu, Zr, Ti, Ni and Ga;

60wt％≤a≤92wt％，6wt％≤b≤38wt％，a+b＝100wt％。

2. the ndfeb permanent magnet material according to claim 1, wherein the weight proportion of the heavy rare earth to the total weight of the anisotropic magnet and the heavy rare earth is 1 wt% to 2 wt%.

3. The ndfeb permanent magnetic material of claim 1, wherein M is selected from Co, Al, Cu, Zr and Ga.

4. The NdFeB permanent magnet material as claimed in any of claims 1 to 3, wherein the NdFeB permanent magnet material comprises a main phase structure and a shell structure around the main phase structure, and the main phase structure is (Nd, Pr)₂Fe₁₄B, the shell layer structure is (Tb, Nd)₂Fe₁₄B。

5. The method for preparing a neodymium-iron-boron permanent magnet material of claim 1, comprising the following steps:

A) mixing anisotropic magnet powder shown as a formula (I) and heavy rare earth powder shown as a formula (II) to obtain mixed magnetic powder, wherein the mass ratio of the heavy rare earth powder in the mixed magnetic powder is 0.1-5 wt%;

B) sequentially carrying out orientation compression, sintering and tempering on the mixed magnetic powder to obtain a neodymium iron boron permanent magnet material;

(Nd,Pr)_xFe_(100-x-y-z)B_yM_z(Ⅰ)；

Tb_aFe_bAl_100-a-b(Ⅱ)；

wherein x is more than or equal to 28.6 wt% and less than or equal to 29.5 wt%, y is more than or equal to 0.85 wt% and less than or equal to 0.9 wt%, z is more than 0 and less than or equal to 2.5 wt%, and M is selected from one or more of Co, Al, Cu, Zr, Ti, Ni and Ga;

60wt％≤a≤92wt％，6wt％≤b≤38wt％，a+b＝100wt％。

6. the method according to claim 5, wherein the anisotropic magnet powder is prepared by a hydrogen-assisted air flow milling process, and the particle size of the anisotropic magnet powder is 1.5 to 3.0 μm.

7. The production method according to claim 5 or 6, characterized in that the production method of the anisotropic magnet powder is specifically:

preparing the materials according to the proportion of each element in the anisotropic magnet powder in the formula (I);

mixing the prepared raw materials and smelting in an inert atmosphere to obtain a master alloy;

rapidly solidifying the master alloy to prepare an alloy sheet;

and crushing the alloy sheet by hydrogen crushing and jet milling to obtain anisotropic magnet powder.

8. The method according to claim 5, wherein the method for preparing the heavy rare earth powder comprises:

proportioning according to the proportion of each element in the formula (II);

mixing the prepared raw materials and smelting in an inert atmosphere to obtain a heavy rare earth master alloy;

crushing the master alloy through a hydrogen crushing-air flow milling process or a ball milling process to obtain heavy rare earth powder; the particle size of the heavy rare earth powder is 0.1-2 mu m.

9. The production method according to claim 5, wherein the orientation profiling is specifically:

and pressing and molding the mixed magnetic powder at 2.3-2.5T, and then carrying out static pressure at 150-200 MPa to obtain a blank magnet.

10. The preparation method according to claim 5, wherein the sintering temperature is 1060-1075 ℃, the sintering time is 2-4 h, the tempering treatment comprises primary tempering and secondary tempering which are sequentially performed in a vacuum environment or a protective atmosphere, the primary tempering temperature is 850-900 ℃, the primary tempering time is 1-3 h, the secondary tempering temperature is 480-550 ℃, and the secondary tempering time is 1-3 h.

Technical Field

The invention relates to the technical field of magnetic materials, in particular to a neodymium iron boron permanent magnet material and a preparation method thereof.

Background

The sintered Nd-Fe-B permanent magnet material is a magnetic material with the highest comprehensive magnetic performance in the existing permanent magnet materials. Because the Nd-Fe-B magnet has high remanence Br and maximum magnetic energy product (BH)_maxThe volume of the magnetic device can be reduced, and the cost of the device can be reduced, so that the material is widely applied to the field of the magnetic devices such as electronic information, medical equipment and new energy vehicles, and has wide application prospect.

With the rapid development of industrialization, the miniaturization requirement of magnetic devices puts higher requirements on the neodymium iron boron magnet, and not only the residual magnetism Br but also the coercive force Hcj are greatly improved. At present, elements such as heavy rare earth Tb and Dy are widely added in industry to improve the anisotropy field, so that the aim of improving the coercive force Hcj of the magnet is fulfilled, but the heavy rare earth Tb and Dy have higher cost, and meanwhile, the heavy rare earth elements can generate an antiferromagnetic effect with iron to greatly reduce the remanence of the magnet; and part of researchers adopt a grain boundary diffusion method to ensure that the remanence of the magnet is not reduced or slightly reduced, namely, a large amount of metal elements Tb and Dy are coated on the surface of the magnet through coating or magnetron sputtering, and finally the neodymium iron boron magnet is prepared through heat treatment. Thus, extensive attention has been paid to studies on reduction of the amount of heavy rare earth while maintaining high coercivity and high remanence.

Disclosure of Invention

The technical problem to be solved by the invention is to provide the neodymium iron boron permanent magnet material, the neodymium iron boron permanent magnet material provided by the application can reduce the use of heavy rare earth elements, and the coercive force is obviously improved under the condition of ensuring that the remanence of a neodymium iron boron magnet is not reduced or slightly reduced.

In view of the above, the application provides a neodymium iron boron permanent magnet material, which is prepared from an anisotropic magnet shown in formula (I) and heavy rare earth shown in formula (II), wherein the mass ratio of the heavy rare earth to the total amount of the anisotropic magnet and the heavy rare earth is 0.1-5 wt%;

(Nd,Pr)_xFe_(100-x-y-z)B_yM_z(Ⅰ)；

Tb_aFe_bAl_100-a-b(Ⅱ)；

wherein x is more than or equal to 28.6 wt% and less than or equal to 29.5 wt%, y is more than or equal to 0.85 wt% and less than or equal to 0.9 wt%, z is more than 0 and less than or equal to 2.5 wt%, and M is selected from one or more of Co, Al, Cu, Zr, Ti, Ni and Ga;

60wt％≤a≤92wt％，6wt％≤b≤38wt％，a+b＝100wt％。

preferably, the weight proportion of the heavy rare earth to the total weight of the anisotropic magnet and the heavy rare earth is 1 wt% to 2 wt%.

Preferably, said M is selected from Co, Al, Cu, Zr and Ga.

Preferably, the neodymium iron boron permanent magnet material comprises a main phase structure and a shell structure positioned around the main phase structure, and the main phase structure is (Nd, Pr)₂Fe₁₄B, the shell layer structure is (Tb, Nd)₂Fe₁₄B。

The application also provides a preparation method of the neodymium iron boron permanent magnet material, which comprises the following steps:

A) mixing anisotropic magnet powder shown as a formula (I) and heavy rare earth powder shown as a formula (II) to obtain mixed magnetic powder, wherein the mass ratio of the heavy rare earth powder in the mixed magnetic powder is 0.1-5 wt%;

B) sequentially carrying out orientation compression, sintering and tempering on the mixed magnetic powder to obtain a neodymium iron boron permanent magnet material;

(Nd,Pr)_xFe_(100-x-y-z)B_yM_z(Ⅰ)；

Tb_aFe_bAl_100-a-b(Ⅱ)；

wherein x is more than or equal to 28.6 wt% and less than or equal to 29.5 wt%, y is more than or equal to 0.85 wt% and less than or equal to 0.9 wt%, z is more than 0 and less than or equal to 2.5 wt%, and M is selected from one or more of Co, Al, Cu, Zr, Ti, Ni and Ga;

60wt％≤a≤92wt％，6wt％≤b≤38wt％，a+b＝100wt％。

preferably, the anisotropic magnet powder is prepared by a hydrogen fracturing-air flow milling process, and the particle size of the anisotropic magnet powder is 1.5-3.0 μm.

Preferably, the method for preparing the anisotropic magnet powder specifically comprises:

preparing the materials according to the proportion of each element in the anisotropic magnet powder in the formula (I);

mixing the prepared raw materials and smelting in an inert atmosphere to obtain a master alloy;

rapidly solidifying the master alloy to prepare an alloy sheet;

and crushing the alloy sheet by hydrogen crushing and jet milling to obtain anisotropic magnet powder.

Preferably, the preparation method of the heavy rare earth powder specifically comprises the following steps:

proportioning according to the proportion of each element in the formula (II);

mixing the prepared raw materials and smelting in an inert atmosphere to obtain a heavy rare earth master alloy;

crushing the master alloy through a hydrogen crushing-air flow milling process or a ball milling process to obtain heavy rare earth powder; the particle size of the heavy rare earth powder is 0.1-2 mu m.

Preferably, the orientation profiling specifically comprises:

and pressing and molding the mixed magnetic powder at 2.3-2.5T, and then carrying out static pressure at 150-200 MPa to obtain a blank magnet.

Preferably, the sintering temperature is 1060-1075 ℃, the sintering time is 2-4 h, the tempering treatment comprises primary tempering and secondary tempering which are sequentially carried out in a vacuum environment or a protective atmosphere, the primary tempering temperature is 850-900 ℃, the primary tempering time is 1 h-3 h, the secondary tempering temperature is 480-550 ℃, and the secondary tempering time is 1 h-3 h.

The application provides a neodymium-iron-boron permanent magnet material which is composed of anisotropic magnets (Nd, Pr)_xFe_(100-x-y-z)B_yM_zAnd heavy rare earth Tb_aFe_bAl_100-a-bPreparing to obtain; in the Nd-Fe-B permanent magnet material, the coercive force can be improved by Tb and Al elements in heavy rare earth, and Tb2 with Tb element capable of forming high anisotropy fieldThe coercive force Hcj can be greatly improved by the Fe4B phase, Al can lubricate the boundary of the grain boundary under the condition of being rich in NdPr grain boundary, the coercive force Hcj is improved, the Fe element has high saturation magnetic polarization strength and high remanence Br is kept; therefore, the neodymium iron boron permanent magnet material provided by the application can obviously improve the coercive force of the neodymium iron boron permanent magnet material under the condition that the residual magnetism is not reduced or slightly reduced by adding the heavy rare earth component and controlling the addition amount of the heavy rare earth component.

Drawings

FIG. 1 shows an anisotropic Nd-Fe-B permanent magnet material [ (NdPr)_29.5Cu_0.2Al_0.1Zr_0.2Co_0.5Ga_0.1Fe_bal.B_0.9]Scanning electron microscope photographs of (a);

FIG. 2 is a scanning electron micrograph of the Nd-Fe-B permanent magnet material obtained in example 1;

fig. 3 is a scanning electron micrograph of the neodymium iron boron permanent magnet material obtained in example 2;

FIG. 4 is a scanning electron micrograph of the Nd-Fe-B permanent magnet material obtained in example 3;

fig. 5 is a scanning electron micrograph of the ndfeb permanent magnet material obtained in comparative example 1.

Detailed Description

For a further understanding of the invention, reference will now be made to the preferred embodiments of the invention by way of example, and it is to be understood that the description is intended to further illustrate features and advantages of the invention, and not to limit the scope of the claims.

In view of the problem of unbalanced coercive force and residual magnetism of the neodymium iron boron magnet in the prior art, the application provides the neodymium iron boron permanent magnet material, which can obviously improve the coercive force of the neodymium iron boron permanent magnet material under the condition that the residual magnetism is not reduced or slightly reduced on the basis of reducing the use amount of heavy rare earth. Specifically, the embodiment of the invention discloses a neodymium iron boron permanent magnet material which is prepared from an anisotropic magnet shown in a formula (I) and heavy rare earth shown in a formula (II), wherein the mass ratio of the heavy rare earth to the total amount of the anisotropic magnet and the heavy rare earth is more than or equal to 0.1 wt% and less than or equal to 5.0 wt%;

(Nd,Pr)_xFe_(100-x-y-z)B_yM_z(Ⅰ)；

Tb_aFe_bAl_100-a-b(Ⅱ)；

wherein x is more than or equal to 28.6 wt% and less than or equal to 29.5 wt%, y is more than or equal to 0.85 wt% and less than or equal to 0.9 wt%, z is more than 0 and less than or equal to 2.5 wt%, and M is selected from one or more of Co, Al, Cu, Zr, Ti, Ni and Ga;

60wt％≤a≤92wt％，6wt％≤b≤38wt％，a+b＝100wt％。

in the Nd-Fe-B permanent magnet material described in the present application, an anisotropic magnet (Nd, Pr)_xFe_(100-x-y-z)B_yM_zThe content of the medium (Nd, Pr) is lower, and the content of the B is lower, so that high remanence Br can be kept, and meanwhile, an NdPr-rich grain boundary phase exists at the grain boundary of the magnet. The M is selected from one or more of Co, Al, Cu, Zr, Ti, Ni and Ga, in a specific embodiment, the M is selected from Co, Al, Cu, Zr and Ga, and in the case that the M is selected from a plurality of alloy elements, the content of each element can be adjusted as long as the sum is in the range of 0 to 2.5(≠ 0). (Nd, Pr) means one or both of Nd and Pr in the present application, and the content thereof may be 28.6 wt%, 28.7 wt%, 28.8 wt%, 28.9 wt%, 29.0 wt%, 29.1 wt%, 29.2 wt%, 29.3 wt%, 29.4 wt%, 29.5 wt%, 29.6 wt%, or 29.7 wt%. The content of B is 0.86 wt%, 0.87 wt%, 0.88 wt%, 0.89 wt% or 0.90 wt%. The content of M is 0.2-2.3 wt%, and in specific embodiments, the content of M is 1.0-1.8 wt%.

Heavy rare earth component Tb_aFe_bAl_100-a-bTb and Al are added to improve the coercive force, Tb can form a Tb2Fe4B phase with a high anisotropy field, the coercive force Hcj can be greatly improved, Al can lubricate the boundary of a grain boundary under the condition of being rich in NdPr grain boundary, the coercive force Hcj is improved, the Fe element has high saturation magnetic polarization strength, and high remanence Br is kept.

In the neodymium iron boron permanent magnet material, the heavy rare earth accounts for 0.1-5 wt% of the total amount of the anisotropic magnet and the heavy rare earth; in a specific embodiment, the heavy rare earth accounts for 1-2 wt% of the total amount of the anisotropic magnet and the heavy rare earth; below 0.1 wt%, the coercivity growth effect is not significant, and above 5 wt%, the remanence Br is reduced too much.

The application also provides a preparation method of the neodymium iron boron permanent magnet material, which comprises the following steps:

A) mixing anisotropic magnet powder shown as a formula (I) and heavy rare earth powder shown as a formula (II) to obtain mixed magnetic powder, wherein the mass ratio of the heavy rare earth powder in the mixed magnetic powder is more than or equal to 0.1 wt% and less than or equal to 5.0 wt%;

B) sequentially carrying out orientation compression, sintering and tempering on the mixed magnetic powder to obtain a neodymium iron boron permanent magnet material;

(Nd,Pr)_xFe_(100-x-y-z)B_yM_z(Ⅰ)；

Tb_aFe_bAl_100-a-b(Ⅱ)

wherein x is more than or equal to 28.6 wt% and less than or equal to 29.5 wt%, y is more than or equal to 0.85 wt% and less than or equal to 0.9 wt%, z is more than 0 and less than or equal to 2.5 wt%, and M is selected from one or more of Co, Al, Cu, Zr, Ti, Ni and Ga;

60wt％≤a≤92wt％，6wt％≤b≤38wt％，a+b＝100wt％。

in the preparation process, firstly, anisotropic magnet powder and heavy rare earth powder are mixed to obtain mixed powder; the mixing time is 1-3 h. Before mixing the two, firstly preparing anisotropic magnet powder and heavy rare earth powder respectively; the preparation method of the anisotropic magnet powder comprises the following steps:

preparing the materials according to the proportion of each element in the anisotropic magnet powder in the formula (I);

mixing the prepared raw materials and smelting in an inert atmosphere to obtain a master alloy;

rapidly solidifying the master alloy to prepare an alloy sheet;

and crushing the alloy sheet by hydrogen crushing and jet milling to obtain anisotropic magnet powder.

The above-mentioned melting, rapid solidification, hydrogen decrepitation and jet milling are technical means well known to those skilled in the art, and the present application is not particularly limited thereto.

The preparation method of the heavy rare earth powder comprises the following steps:

proportioning according to the proportion of each element in the formula (II);

mixing the prepared raw materials and smelting in an inert atmosphere to obtain a heavy rare earth master alloy;

and (3) crushing the master alloy through a hydrogen crushing-air flow milling process or a ball milling process to obtain heavy rare earth powder.

Also, the above-mentioned processes of melting, hydrogen breaking and jet milling are technical means well known to those skilled in the art, and there is no particular limitation in this application.

The particle size of the anisotropic magnet powder is 1.5-3.0 mu m, and the particle size of the heavy rare earth powder is 0.1-2.0 mu m.

After the raw materials are mixed, sequentially carrying out orientation compression, sintering and tempering on the obtained mixed magnetic powder to obtain a neodymium iron boron permanent magnet material; in the above process, the orientation profiling, sintering and tempering are technical process means well known to those skilled in the art, and the process operation thereof is not particularly limited in this application. And the orientation compression molding is to compress the mixed magnetic powder into a mold under 2.3-2.5T, and then carry out static pressure under 150-200 MPa to obtain a blank magnet. The sintering temperature is 1060-1075 ℃, and the time is 2-4 h. And performing primary tempering and secondary tempering in sequence in a tempering vacuum environment or a protective atmosphere, wherein the temperature of the primary tempering is 850-900 ℃, the time of the primary tempering is 1-3 h, the temperature of the secondary tempering is 480-550 ℃, and the time of the secondary tempering is 1-3 h.

The neodymium iron boron permanent magnet material comprises a main phase structure and a shell structure uniformly distributed around the main phase structure, wherein the shell structure comprises the components of (Tb, Nd)₂Fe₁₄B, the main phase structure is (Nd, Pr)₂Fe₁₄B。

According to the preparation method of the high-performance neodymium iron boron permanent magnet material, the coercive force of the neodymium iron boron permanent magnet material can be obviously improved without reducing or slightly reducing the residual magnetism, and the magnetic performance of the neodymium iron boron permanent magnet material is not influenced, so that the preparation method is suitable for large-size blank mass production; the preparation method of the high-performance neodymium iron boron permanent magnet material provided by the invention can effectively reduce the use amount of heavy rare earth. The preparation method of the high-performance neodymium iron boron permanent magnet material provided by the invention is simple and feasible, and can be used for industrial production.

For further understanding of the present invention, the following examples are provided to illustrate the preparation method of the ndfeb magnetic material provided by the present invention, and the scope of the present invention is not limited by the following examples.