WO2021169886A1

WO2021169886A1 - Neodymium-iron-boron magnet material, raw material composition, preparation method therefor and use thereof

Info

Publication number: WO2021169886A1
Application number: PCT/CN2021/077171
Authority: WO
Inventors: 骆溁; 黄佳莹; 廖宗博; 蓝琴; 林玉麟; 师大伟; 谢菊华; 龙严清
Original assignee: 厦门钨业股份有限公司; 福建省长汀金龙稀土有限公司
Priority date: 2020-02-26
Filing date: 2021-02-22
Publication date: 2021-09-02
Also published as: CN111223624A; JP2023511776A; CN111223624B; JP7470804B2

Abstract

Disclosed in the present invention are a neodymium-iron-boron magnet material, a raw material composition, a preparation method therefor and a use thereof. The raw material composition comprises: R: 28-33%, R being rare earth elements and comprising R1 and R2, R1 being a rare earth element added during smelting, R1 comprising Nd and Dy, R2 being a rare earth element added during grain boundary diffusion, R2 comprising Tb, and the content of R2 being 0.2-1%; Co: < 0.5% but not 0; M: ≤ 0.4% but not 0, M comprising one or more elements from among Ti, Ni, V, Nb, Ta, Cr, Mo, W, Mn, Zr, Hf, and Ag; Cu: ≤ 0.15% but not 0; B: 0.9-1.1%; Fe: 60-70%; the percentages being the weight percentages occupied by each component in the raw material composition. The magnet material of the present invention features the advantages of high remanence, high coercivity, and excellent high-temperature performance.

Description

Neodymium iron boron magnet material, raw material composition, preparation method and application

Technical field

The invention specifically relates to a neodymium iron boron magnet material, a raw material composition, and a preparation method and application.

Background technique

Nd-Fe-B permanent magnetic material is based on Nd ₂ Fe _l4 B compound, which has the advantages of high magnetic properties, low thermal expansion coefficient, easy processing and low price. Since its introduction, it has grown at an average annual rate of 20-30%. Become the most widely used permanent magnet material. According to the preparation method, Nd-Fe-B permanent magnets can be divided into three types: sintering, bonding and hot pressing. Among them, sintered magnets account for more than 80% of the total output and are the most widely used.

With the continuous optimization of the preparation process and magnet composition, the maximum energy product of sintered Nd-Fe-B magnets has approached the theoretical value. With the vigorous development of emerging industries such as wind power generation, hybrid electric vehicles and inverter air conditioners in recent years, the demand for high-performance Nd-Fe-B magnets has increased. The performance of the magnet, especially the coercivity, puts forward higher requirements.

The United States patent application US5645651A shows through Figure 1 that the Curie temperature of the Nd-Fe-B magnet will increase with the increase of the Co content. In addition, the comparison between sample 9 and sample 2 in Table 1 shows that the Curie temperature of the Nd-Fe-B magnet Adding 20at% of Co can increase the coercivity while maintaining the remanence basically unchanged compared to the solution without adding Co. Therefore, Co is widely used in high-tech fields such as neodymium iron boron rare earth permanent magnets, samarium cobalt rare earth permanent magnets, batteries, etc. However, Co is an important strategic resource and the price is relatively expensive.

Chinese patent document CN110571007A discloses a rare earth permanent magnet material, which adds more than 1.5% of heavy rare earth elements and more than 0.8% of cobalt at the same time, and finally obtains Nd-Fe-B with better coercivity and magnetic properties. magnet.

To sum up, in the prior art, NdFeB magnet materials with better magnetic properties (remanence, coercivity and thermal stability) need to add a large amount of heavy rare earth elements and cobalt elements, which is costly. Under the premise of a small amount of heavy rare earth elements or cobalt elements, technical solutions that can still reach a considerable level or even better have yet to be developed.

Summary of the invention

The invention aims to overcome the need to add a large amount of cobalt element or heavy rare earth element to the NdFeB magnet material in the prior art to improve the magnetic properties (remanence, coercivity and thermal stability) of the NdFeB magnet material, but Due to the high cost defect, a neodymium iron boron magnet material, raw material composition, preparation method and application are provided. The neodymium iron boron magnet material of the present invention has higher remanence, coercivity, and good thermal stability.

The present invention adopts the following technical solutions to solve the above technical problems.

The present invention provides a raw material composition of neodymium iron boron magnet material, which includes the following components by mass content: R: 28-33%;

The R is a rare earth element, R includes R1 and R2, the R1 is a rare earth element added during smelting, and the R1 includes Nd and Dy;

The R2 is a rare earth element added during grain boundary diffusion, the R2 includes Tb, and the content of the R2 is 0.2-1%;

Co: <0.5%, but not 0;

M: ≤0.4%, but not 0, the type of M includes one or more of Ti, Ni, V, Nb, Ta, Cr, Mo, W, Mn, Zr, Hf, and Ag;

Cu: ≤0.15%, but not 0;

B: 0.9～1.1%;

Fe: 60-70%; the percentage is the mass percentage of the content of each component in the total mass of the raw material composition.

In the present invention, the content of R in the raw material composition is preferably 29 to 32.6%, such as 29.58%, 29.75%, 29.8%, 30.65%, 30.7%, 30.9%, 30.95%, 31.35% or 32.6% %, more preferably 29-31%, and the percentage is the mass percentage of the total mass of the raw material composition.

In the present invention, the content of Nd in R1 of the raw material composition can be conventional in the art, preferably 28 to 32.5%, such as 28.6%, 29.9%, 30.4% or 32.1%, and the percentage is The mass percentage of the total mass of the raw material composition.

In the present invention, the content of Dy in said R1 is preferably less than 0.3%, but not 0, such as 0.05%, 0.08%, 0.1%, 0.15% or 0.2%, preferably 0.1 to 0.2 %, the percentage is the mass percentage of the total mass of the raw material composition.

In the present invention, the R1 may also include other conventional rare earth elements in the art, for example, including one or more of Pr, Ho, Tb, Gd, and Y.

Wherein, when the R1 contains Pr, the addition form of Pr can be conventional in the art, for example, in the form of PrNd, or in the form of a mixture of pure Pr and pure Nd, or, in the form of "PrNd, pure Pr and pure Nd "Mixture" is added jointly. When added in the form of PrNd, Pr:Nd is preferably 25:75 or 20:80; when added in the form of a mixture of pure Pr and pure Nd, or when added as a mixture of "PrNd, pure Pr and pure Nd When added together, the content of Pr is preferably 0.1-2%, for example 0.2%, and the percentage is the mass percentage of the content of each component in the total mass of the raw material composition. The pure Pr or pure Nd in the present invention generally means that the purity is above 99.5%.

Wherein, when the R1 includes Ho, the content of Ho is preferably 0.1-0.2%, and the percentage is the mass percentage of the total mass of the neodymium iron boron magnet material.

Wherein, when the R1 includes Gd, the content of Gd is preferably 0.1-0.2%, and the percentage is a mass percentage of the total mass of the neodymium iron boron magnet material.

Wherein, when the R1 includes Y, the content of Y is preferably 0.1-0.2%, and the percentage is the mass percentage of the total mass of the raw material composition.

In the present invention, the content of R2 is preferably 0.2% to 0.9%, such as 0.2%, 0.3%, 0.5%, 0.6%, 0.8% or 0.9%, more preferably 0.2% to 0.8%, and the percentage is The mass percentage of the total mass of the raw material composition.

In the present invention, the content of Tb in the R2 is preferably 0.2-0.9%, such as 0.2%, 0.3%, 0.5%, 0.6%, 0.8% or 0.9%, more preferably 0.2-0.8%, percentage It is the mass percentage of the total mass of the raw material composition.

In the present invention, the R2 preferably further includes one or more of Pr, Dy, Ho and Gd.

Wherein, when the R2 contains Pr, the content of Pr is preferably less than 0.2%, but not 0, such as 0.1%, and the percentage is the mass percentage of the total mass of the raw material composition.

Wherein, when the R2 includes Dy, the content of Dy is preferably 0.3% or less, but not 0, such as 0.1%, and the percentage is the mass percentage of the total mass of the raw material composition.

Wherein, when the R2 includes Ho, the content of Ho is preferably 0.2% or less, but not 0, such as 0.1%, and the percentage is the mass percentage of the total mass of the raw material composition.

Wherein, when the R2 contains Gd, the content of Gd is preferably 0.2% or less, but not 0, such as 0.1%, and the percentage is the mass percentage of the total mass of the raw material composition.

In the present invention, the content of Co is preferably 0.45% or less, but not 0, such as 0.05%, 0.1%, 0.2%, 0.3%, 0.4% or 0.45%, more preferably 0.05-0.4%, The percentage is the mass percentage of the total mass of the raw material composition.

In the present invention, the content of M is preferably 0.08-0.35%, more preferably 0.1-0.15%, such as 0.08%, 0.1%, 0.16%, 0.2%, 0.25%, 0.3% or 0.35%, percentage It is the mass percentage of the total mass of the raw material composition.

In the present invention, the type of M is preferably one or more of Ti, Zr, Nb, Ni, V, Ta, Cr, Mo, W, Mn, Hf and Ag.

Wherein, when the M contains Ti, the content of Ti is preferably 0.05-0.3%, such as 0.05%, 0.1% or 0.3%, and the percentage is the mass percentage of the total mass of the raw material composition.

Wherein, when the M contains Zr, the content of Zr is preferably 0.08-0.35%, such as 0.08%, 0.2% or 0.35%, and the percentage is the mass percentage of the total mass of the raw material composition.

Wherein, when the M contains Nb, the Nb content is preferably 0.05-0.3%, such as 0.05%, 0.2% or 0.3%, and the percentage is the mass percentage of the total mass of the raw material composition.

In the present invention, in the raw material composition, the M preferably may further include one or more of Bi, Sn, Zn, Ga, In, Au and Pb.

Wherein, when the M contains Ga, the content of Ga is preferably greater than 0.2%, or less than 0.01%, but not 0, and the percentage is the mass percentage of the total mass of the raw material composition.

When the M element contains Ga, and Ga≥0.2%, preferably, Ti+Nb≤0.07% in the composition of the M element.

In the present invention, the raw material composition preferably further includes Al.

Wherein, the content of Al is preferably below 0.2%, but not 0, such as 0.03 to 0.2%, such as 0.1%, and the percentage is the mass percentage of the total mass of the raw material composition.

When the M contains Ga and Ga≤0.01%, preferably, Al+Ga+Cu≤0.11% in the composition of the M element.

In the present invention, the content of Cu is preferably 0.05 to 0.15%, for example, 0.05%, 0.06%, 0.07%, 0.08%, 0.1% or 0.15%; or the content of Cu is preferably below 0.08% , But not 0, such as 0.05%, 0.06% or 0.07%; the percentage is the mass percentage of the total mass of the raw material composition.

In the present invention, the method of adding Cu preferably includes adding during smelting and/or adding during grain boundary diffusion. When Cu is added during grain boundary diffusion, the content of Cu added during grain boundary diffusion is preferably 0.05 to 0.15%, and the percentage is a mass percentage of the total mass of the raw material composition. When the Cu is added when it diffuses at the grain boundary, the Cu is preferably added in the form of a PrCu alloy; wherein the mass percentage of the Cu to the PrCu is preferably 0.1-17%.

In the present invention, the content of B is preferably 0.97-1.1%, such as 0.99% or 1%, and the percentage is the mass percentage of the total mass of the raw material composition.

In the present invention, the content of Fe is preferably 65 to 79.5%, for example, 65.4%, 67.28%, 67.31%, 67.53%, 67.67%, 67.7%, 67.74%, 68.76%, 68.91% or 69%. It is the mass percentage of the total mass of the raw material composition.

In the present invention, the raw material composition preferably includes the following components: R: 29 to 32.6%; R includes R1 and R2, the R1 includes Nd and Dy, and the amount of Dy is 0.3% or less, but not 0, the R1 is a rare earth element added during smelting, the content of R2 is 0.2-1%, the R2 includes Tb, and the R2 is a rare earth element added during grain boundary diffusion; Co: 0.05-0.45% ; M: 0.08～0.35%, the M includes one or more of Ti, Nb and Zr; Cu: 0.05～0.15%; B: 0.97～1.1%; Fe: 65～79.5%; the percentages are for each group The component content accounts for the mass percentage of the total mass of the raw material composition.

In the present invention, the raw material composition preferably includes the following components: R: 29-31%; R includes R1 and R2, said R1 includes Nd and Dy, and the amount of Dy is 0.1-0.2%, so The R1 is a rare earth element added during smelting, the content of R2 is 0.2-0.8%, the R2 includes Tb, and the R2 is a rare earth element added during grain boundary diffusion; Co: 0.05-0.4%; M: 0.1 ~0.15%, the M includes one or more of Ti, Nb and Zr; Cu: less than 0.08% but not 0; B: 0.97-1.1%; Fe: 65-79.5%; the percentage is each component The content accounts for the mass percentage of the total mass of the raw material composition.

In a preferred embodiment of the present invention, the raw material composition of the neodymium iron boron magnet material includes the following components by mass content: R1 is Nd 28.6%, Dy 0.05%, Pr 0.1%, and R1 is added during smelting R2 is Tb 1%, the R2 is the rare earth element added during grain boundary diffusion; Co 0.05%; Ti 0.05%; Nb 0.2%; Cu 0.05%; B 0.99% and Fe 68.91%, the percentages are each The component content accounts for the mass percentage of the total mass of the raw material composition.

In a preferred embodiment of the present invention, the raw material composition of the neodymium iron boron magnet material includes the following components by mass content: R1 is Nd 28.6%, Dy 0.1%, Pr 0.2%, and R1 is added during smelting R2 is Tb 0.9%, the R2 is the rare earth element added during grain boundary diffusion; Co 0.05%; Ti 0.1%; Cu 0.05%; B 1% and Fe 69%, the percentages are the content of each component The mass percentage of the total mass of the raw material composition.

In a preferred embodiment of the present invention, the raw material composition of the neodymium iron boron magnet material includes the following components by mass content: R1 is Nd 28.6%, Dy 0.08%, and R1 is a rare earth element added during smelting; R2 is Tb 0.9%, the R2 is the rare earth element added during grain boundary diffusion; Co 0.1%; Ti 0.3%; Nb 0.05%; Ga 0.05%; Cu 0.06%; B 1.1% and Fe 68.76%, the percentages are each The component content accounts for the mass percentage of the total mass of the raw material composition.

In a preferred embodiment of the present invention, the raw material composition of the neodymium iron boron magnet material includes the following components by mass content: R1 is Nd 29.9%, Dy 0.1%, and the R1 is a rare earth element added during smelting; R2 is Tb 0.8%, Pr 0.1%, the R2 is rare earth element added during grain boundary diffusion; Co 0.1%; Zr 0.2%; Al 0.2%; Cu added during smelting is 0.03%, added during grain boundary diffusion Cu is 0.05%; B is 0.99% and Fe is 67.53%, and the percentages are the mass percentages of the content of each component in the total mass of the raw material composition.

In a preferred embodiment of the present invention, the raw material composition of the neodymium iron boron magnet material includes the following components by mass content: R1 is Nd 30.4%, Dy 0.05%, and R1 is a rare earth element added during smelting; R2 is Tb 0.8%, Dy 0.1%, the R2 is the rare earth element added during grain boundary diffusion; Co 0.2%; Zr 0.08%; Cu 0.1%; B 0.99% and Fe 67.28%, the percentages are the content of each component The mass percentage of the total mass of the raw material composition.

In a preferred embodiment of the present invention, the raw material composition of the neodymium iron boron magnet material includes the following components by mass content: R1 is Nd 29.9%, Dy 0.15%, and R1 is a rare earth element added during smelting; R2 is Tb 0.6%, the R2 is the rare earth element added during grain boundary diffusion; Co 0.2%; Zr 0.35%; Cu 0.1%; B 1% and Fe 67.7%, the percentages are the content of each component in the raw material combination The mass percentage of the total mass of the material.

In a preferred embodiment of the present invention, the raw material composition of the neodymium iron boron magnet material includes the following components by mass content: R1 is Nd 29.9%, Dy 0.2%, and R1 is a rare earth element added during smelting; R2 is Tb 0.6%, said R2 is the rare earth element added during grain boundary diffusion; Co 0.3%; Nb 0.05%; Ga 0.01%; Al 0.1%, Cu 0.07%; B 1.1% and Fe 67.67%, the percentages are each The component content accounts for the mass percentage of the total mass of the raw material composition.

In a preferred embodiment of the present invention, the raw material composition of the neodymium iron boron magnet material includes the following components by mass content: R1 is Nd 30.4%, Dy 0.05%, and R1 is a rare earth element added during smelting; R2 is Tb 0.3%, Pr 0.2%, the R2 is rare earth element added during grain boundary diffusion; Co 0.4%; Nb 0.2%; Cu added during melting is 0.12%, and Cu added during grain boundary diffusion is 0.03% B 0.99% and Fe 67.31%, the percentages are the mass percentages of the content of each component in the total mass of the raw material composition.

In a preferred embodiment of the present invention, the raw material composition of the neodymium iron boron magnet material includes the following components by mass content: R1 is Nd 32.1%, Dy 0.3%, and the R1 is a rare earth element added during smelting; R2 is Tb 0.2%, the R2 is the rare earth element added during grain boundary diffusion; Co 0.45%; Nb 0.3%; Cu 0.15%; B 1.1% and Fe 65.4%, the percentages are the content of each component in the raw material combination The mass percentage of the total mass of the material.

In a preferred embodiment of the present invention, the raw material composition of the neodymium iron boron magnet material includes the following components by mass content: R1 is Nd 29.9%, Dy 0.2%, and R1 is a rare earth element added during smelting; R2 is Tb 0.6%, the R2 is the rare earth element added during grain boundary diffusion; Co 0.3%; Nb 0.05%; Ga 0.01%; Al 0.03%; Cu 0.07%; B 1.1% and Fe 67.74%, the percentages are each The component content accounts for the mass percentage of the total mass of the raw material composition.

The present invention also provides a preparation method of neodymium iron boron magnet material, which adopts the raw material composition as described above. The preparation method is a conventional diffusion method in the art, wherein the R1 element is added in the smelting step, The R2 element is added in the grain boundary diffusion step.

In the present invention, the preparation method preferably includes the following steps: the elements other than R2 in the raw material composition of the neodymium iron boron magnet material are smelted, powdered, molded, and sintered to obtain a sintered body, and then the The mixture of the sintered body and the R2 may diffuse through the grain boundary.

Wherein, the smelting operation and conditions can be a conventional smelting process in the field. Generally, the elements other than R2 in the raw material composition of the neodymium iron boron magnet material are smelted and casted by ingot casting process and quick-setting sheet process. Obtain alloy flakes.

Those skilled in the art know that because rare earth elements are usually lost in the smelting and sintering process, in order to ensure the quality of the final product, an additional 0-0.3wt% rare earth element (generally Is Nd element), the percentage is the mass percentage of the content of the additional rare earth element to the total content of the raw material composition; in addition, the content of this part of the additional rare earth element is not included in the scope of the raw material composition.

The smelting temperature may be 1300 to 1700°C, preferably 1450 to 1550°C.

The melting environment may be a vacuum of 0.05 Pa.

The smelting equipment is generally an intermediate frequency vacuum smelting furnace, such as an intermediate frequency vacuum induction rapid solidification belt spinning furnace.

Wherein, the operation and conditions of the pulverizing can be conventional pulverizing processes in the field, and generally include hydrogen crushing pulverizing and/or jet milling pulverizing.

The hydrogen crushing and pulverizing generally includes hydrogen absorption, dehydrogenation and cooling treatment. The temperature of the hydrogen absorption is generally 20 to 200°C. The temperature of the dehydrogenation is generally 400-650°C, preferably 500-550°C. The pressure of the hydrogen absorption is generally 50-600 kPa, preferably 300-500 kPa.

The air-jet milling powder is generally carried out under the conditions of 0.1-2 MPa, preferably 0.5-0.7 MPa. The gas stream in the gas stream milling powder can be, for example, nitrogen gas. The time for the air jet milling can be 2 to 4 hours.

Wherein, the molding operation and conditions can be conventional molding processes in the field. For example, the magnetic field forming method. The magnetic field strength of the magnetic field forming method is generally above 1.5T.

Wherein, the sintering operation and conditions can be conventional sintering processes in the field.

The sintering can be carried out under the condition that the degree of vacuum is lower than 0.5Pa.

The sintering temperature may be 1000-1200°C.

The sintering time may be 0.5-10h, preferably 2-5h.

In the present invention, those skilled in the art know that the R2 coating operation is generally included before the grain boundary diffusion.

Wherein, the R2 is generally coated in the form of fluoride or a low melting point alloy, such as fluoride of Tb. When Dy is further contained, it is preferable that Dy is coated in the form of fluoride of Dy.

Wherein, when the R2 contains Pr, preferably, the Pr is added in the form of a PrCu alloy.

When the R2 contains Pr and Pr participates in the grain boundary diffusion in the form of a PrCu alloy, in the PrCu alloy, the mass of the Cu and the PrCu alloy is preferably 0.1-17%. The timing of adding the Cu in the preparation method is preferably the grain boundary diffusion step, or it is added at the same time as the smelting step and the grain boundary diffusion step.

In the present invention, the operation and conditions of the grain boundary diffusion treatment can be a conventional grain boundary diffusion process in the art.

The temperature of the grain boundary diffusion may be 800-1000°C, for example 850°C.

The time for the grain boundary diffusion may be 5-20h, preferably 5-15h.

After the grain boundary diffuses, a low-temperature tempering treatment is also performed according to the conventional practice in the art. The temperature of the low-temperature tempering treatment may generally be 460-560°C. The low-temperature tempering time can generally be 1 to 3 hours.

The invention also provides a neodymium iron boron magnet material prepared by the above preparation method.

The present invention also provides a neodymium iron boron magnet material, which includes the following components by mass content: R: 28-33%; said R includes R1 and R2, said R1 includes Nd and Dy, and said R2 includes Tb. ; The content of R2 is 0.2-1wt%;

Co: <0.5%, but not 0;

Cu: ≤0.15%, but not 0;

B: 0.9～1.5%;

Fe: 60-70%; the percentage is the mass percentage of the mass of each component to the total mass of the neodymium iron boron magnet material;

The neodymium iron boron magnet material comprises Nd ₂ Fe _l4 B crystal grains and its shell layer, _{two grain boundaries adjacent to the Nd 2} Fe _l4 B crystal grains and a grain boundary triangle region; wherein the heavy rare earth elements in R1 are mainly distributed In the Nd ₂ Fe ₁₄ B crystal grains, R2 is mainly distributed in the shell layer, the two-grain boundary and the grain boundary triangle area, and the area of the grain boundary triangle area accounts for 1.8 to 2.99%; the two-grain grain boundary The continuity of the grain boundary is more than 96%; the mass ratio of C and O in the triangular region of the grain boundary is 0.4-0.5%; the mass ratio of C and O in the two-grain grain boundary is 0.3-0.5%.

In the present invention, "the heavy rare earth elements in R1 are mainly distributed in Nd ₂ Fe _l4 B crystal grains" can be understood as the main distribution of heavy rare earth elements in R1 caused by the conventional smelting and sintering process in this field (generally refers to more than 95wt% ) In the Nd ₂ Fe _l4 B crystal grains, a small amount is distributed in the grain boundaries. "R2 is mainly distributed in the shell layer" can be understood as the R2 caused by the conventional grain boundary diffusion process in this field is mainly distributed (generally means more than 95wt%) in the shell layer and the second particle of the _{Nd 2} Fe _{l4 B crystal grains.} A small part of the grain boundary and the grain boundary triangle area will also diffuse into the Nd ₂ Fe _l4 B crystal grains, for example, at the outer edge of the _{Nd 2} Fe _{l4 B crystal grain.}

In the present invention, the calculation method of the grain boundary continuity refers to the length occupied by phases other than voids in the grain boundary (phases such as B-rich phase, rare earth-rich phase, rare earth oxide, rare earth carbide, etc.) and The ratio of the total grain boundary length. Grain boundary continuity of more than 96% can be called continuous channel.

In the present invention, the grain boundary triangle area generally refers to a place where three or more grain boundary phases intersect, and there are B-rich phases, rare earth-rich phases, rare earth oxides, rare earth carbides, and cavities distributed. The calculation method of the area ratio of the grain boundary triangle area refers to the ratio of the area of the grain boundary triangle area to the total area of the "grains and grain boundaries".

Among them, rare earth oxides and rare earth carbides are mainly produced by the C and O elements introduced during the preparation process. Due to the high content of rare earths in the grain boundaries, C and O are usually more distributed in the grain boundaries in the magnet material, so they exist in the form of rare earth carbides and rare earth oxides, respectively. It should be noted that: C and O elements are introduced in conventional ways in the field, generally impurity introduction or atmosphere introduction. Specifically, for example, in the process of jet milling and pressing, additives are introduced. During sintering, these elements will be heated by heating. Additives are removed, but a small amount of C and O elements will inevitably remain; for another example, a small amount of O elements will inevitably be introduced due to the atmosphere in the preparation process. In the present invention, the content of C and O in the final NdFeB magnet material product obtained after testing is only below 1000 ppm and 1200 ppm respectively, which belong to the category of conventional acceptable impurities in the field, so they are not included in the product element statistical table.

In the present invention, the area of the grain boundary triangle area is preferably 1.96 to 2.99%, such as 1.96%, 1.98%, 2.05%, 2.36%, 2.41%, 2.54%, 2.73%, 2.78%, 2.83% or 2.99%.

In the present invention, the grain boundary continuity is preferably 97% or more, for example, 97.85%, 97.92%, 98.01%, 98.03%, 98.03%, 98.07%, 98.12%, 98.13%, 98.18% or 98.54%, more Preferably, it is above 98%.

In the present invention, the mass ratio of C and O in the grain boundary triangle region is preferably 0.41 to 0.49%, for example, 0.41%, 0.44%, 0.45%, 0.46%, 0.47%, 0.48%, or 0.49%. , More preferably 0.41 to 0.48%, the percentage is the ratio of the mass of C and O in the triangular region of the grain boundary to the total mass of all elements in the grain boundary.

In the present invention, the mass ratio of C and O in the two-grain boundary is preferably 0.3-0.4%, such as 0.3%, 0.34%, 0.35%, 0.36%, 0.37%, 0.38% or 0.4%, More preferably, it is 0.34-0.4%, and the percentage is the ratio of the mass of C and O in the grain boundary of the two particles to the total mass of all elements in the grain boundary.

In the present invention, those skilled in the art know that C and O elements usually exist in the form of rare earth carbides and rare earth oxides in the grain boundary phase, so "the mass ratio of C and O in the grain boundary triangle area" and " The mass ratios of C and O in the grain boundaries of the two grains correspond to heterogeneous rare earth carbides and rare earth oxides, respectively. In addition, according to the "mass ratio of C and O in the triangular area of the grain boundary" minus the "mass ratio of C and O in the two grain boundaries (%)" in the embodiment, the difference is smaller than the comparison ratio, and it can be obtained The conclusion that the impurity phase migrates from the triangular area of the grain boundary to the two-grain grain boundary explains the reason for the improvement of the continuity of the grain boundary from the mechanism.

In the present invention, in the two-particle grain boundary of the neodymium iron boron magnet material, in addition to the two impurity phases of rare earth oxide and rare earth carbide, preferably, a new phase is also detected in the two-particle grain boundary, The chemical composition of the new phase is: R _x (Fe+Co) _100-xyz Cu _y M _z , wherein R in R _x (Fe+Co) _100-xyz Cu _y M _z includes Nd, Dy and Tb M includes one or more of Ti, Ni, V, Nb, Ta, Cr, Mo, W, Mn, Zr, Hf, Zn and Ag; x is 78-81; y It is 0.4 to 0.8; z is 0.1 or less, but not 0.

In R _x (Fe+Co) _100-xyz Cu _y M _z , x is preferably 78.89 to 80.8, y is preferably 0.55 to 0.66, and z is preferably 0.02 to 0.06.

In a preferred embodiment of the present invention, the structure of the new phase is, for example, R _79.43 (Fe+Co) _19.92 Cu _0.63 M _0.02 , R _78.89 (Fe+Co) _20.49 Cu _0.58 M _0.04 , R _80.72 (Fe+Co) Co) _18.68 Cu _0.55 M _0.05 , R _79.21 (Fe+Co) _20.11 Cu _0.66 M _0.02 , R _80.09 (Fe+Co) _19.22 Cu _0.65 M _0.04 , R _79.04 (Fe+Co) _20.31 Cu _0.61 M _0.04 , R _79.76 ( Fe+Co) _19.64 Cu _0.58 M _0.02 , R _79.71 (Fe+Co) _19.65 Cu _0.62 M _0.02 , R _80.18 (Fe+Co) _19.16 Cu _0.62 M _0.04 , R _79.4 (Fe+Co) _19.94 Cu _0.64 M _0.02 .

In the present invention, the chemical composition is R _x (Fe+Co) _100-xyz Cu _y M _z . The area of the new phase in the two-grain boundaries is better than the total area of the two-grain boundaries. 0.2-2.6%, such as 0.21%, 0.34%, 0.85%, 1.08%, 1.15%, 1.21%, 1.33%, 1.87%, 2.34% or 2.55%, more preferably 0.34-2.55%.

The inventor speculates that the new phase is formed at the grain boundary of the two particles, so the continuity of the grain boundary is further improved, thereby improving the performance of the magnet.

In the present invention, the content of R in the neodymium iron boron magnet material is preferably 29 to 32.6%, such as 29.58%, 29.75%, 29.8%, 30.65%, 30.7%, 30.9%, 30.95%, 31.35 % Or 32.6%, more preferably 29-31%, and the percentage is the mass percentage of the total mass of the neodymium iron boron magnet material.

In the present invention, in the R1 of the neodymium iron boron magnet material, the Nd content can be conventional in the art, preferably 28 to 32.5%, such as 28.6%, 29.9%, 30.4% or 32.1%, and the percentage is It accounts for the mass percentage of the total mass of the neodymium iron boron magnet material.

In the present invention, in the R1 of the neodymium iron boron magnet material, the content of Dy is preferably less than 0.3%, but not 0, such as 0.05%, 0.08%, 0.1%, 0.15%, 0.2% or 0.3 %, preferably 0.1-0.2%, and the percentage is the mass percentage of the total mass of the neodymium iron boron magnet material.

Wherein, when the R1 contains Pr, the addition form of Pr can be conventional in the art, for example, in the form of PrNd, or in the form of a mixture of pure Pr and pure Nd, or, in the form of "PrNd, pure Pr and pure Nd "Mixture" is added jointly. When added in the form of PrNd, Pr:Nd is preferably 25:75 or 20:80; when added in the form of a mixture of pure Pr and pure Nd, or when added as a mixture of "PrNd, pure Pr and pure Nd When added together, the content of the Pr is preferably 0.1-2%, for example 0.2%, and the percentage is the mass percentage of the total mass of the neodymium iron boron magnet material. The pure Pr or pure Nd in the present invention generally refers to a purity of 99.5% or more.

Wherein, when the R1 includes Y, the content of Y is preferably 0.1-0.2%, and the percentage is the mass percentage of the total mass of the neodymium iron boron magnet material.

In the present invention, the content of R2 is preferably 0.2 to 0.9%, such as 0.2%, 0.3%, 0.5%, 0.6% or 0.8%, more preferably 0.2 to 0.8%, and the percentage is based on the neodymium iron The mass percentage of the total mass of the boron magnet material.

In the present invention, the content of Tb in the R2 is preferably 0.2-0.9%, such as 0.2%, 0.3%, 0.5%, 0.6%, 0.8% or 0.9%, more preferably 0.2-0.8%, percentage It is the mass percentage of the total mass of the neodymium iron boron magnet material.

Wherein, when the R2 contains Pr, the content of Pr is preferably less than 0.2%, for example 0.1%, and the percentage is the mass percentage of the total mass of the neodymium iron boron magnet material.

Wherein, when the R2 includes Dy, the content of Dy is preferably 0.3% or less, for example 0.1%, and the percentage is a mass percentage of the total mass of the neodymium iron boron magnet material.

Wherein, when the R2 includes Ho, the content of Ho is preferably 0.2% or less, for example 0.1%, and the percentage is the mass percentage of the total mass of the neodymium iron boron magnet material.

Wherein, when the R2 includes Gd, the content of Gd is preferably less than 0.2%, such as 0.1%, and the percentage is the mass percentage of the total mass of the neodymium iron boron magnet material.

In the present invention, the content of Co is preferably 0.45% or less, but not 0, such as 0.05%, 0.1%, 0.2%, 0.3% or 0.4%, more preferably 0.05 to 0.4%, and the percentage is The mass percentage of the total mass of the neodymium iron boron magnet material.

In the present invention, the content of M is preferably 0.08-0.35%, such as 0.08%, 0.1%, 0.16%, 0.2%, 0.25%, 0.3% or 0.35%, more preferably 0.1-0.15%, percentage It is the mass percentage of the total mass of the neodymium iron boron magnet material.

Wherein, when the M contains Ti, the content of Ti is preferably 0.05-0.3%, such as 0.1%, and the percentage is a mass percentage of the total mass of the neodymium iron boron magnet material.

Wherein, when the M includes Zr, the content of Zr is preferably 0.08-0.35%, such as 0.2%, and the percentage is the mass percentage of the total mass of the neodymium iron boron magnet material.

Wherein, when the M contains Nb, the Nb content is preferably 0.05-0.3%, for example 0.2%, and the percentage is the mass percentage of the total mass of the neodymium iron boron magnet material.

In the present invention, in the neodymium iron boron magnet material, the M preferably further includes one or more of Bi, Sn, Zn, Ga, In, Au and Pb.

Wherein, when the M contains Ga, the content of Ga is preferably more than 0.2%, but not 0, or less than 0.01%, but not 0, and the percentage is based on the total neodymium iron boron magnet material. The mass percentage of mass.

When the M element contains Ga and Ga≥0.2%, preferably Ti+Nb≤0.07% in the composition of the M element, the percentage is the mass percentage of the total mass of the neodymium iron boron magnet material.

In the present invention, the neodymium iron boron magnet material preferably further includes Al.

Wherein, the content of Al is preferably less than 0.2%, but not 0, such as 0.03 to 0.2%, such as 0.1%, and the percentage is a mass percentage of the total mass of the neodymium iron boron magnet material.

When the M contains Ga and Ga≤0.01%, preferably, Al+Ga+Cu≤0.11% in the composition of the M element, and the percentage is the mass percentage of the total mass of the neodymium iron boron magnet material.

In the present invention, the content of Cu is preferably 0.05 to 0.15%, for example, 0.05%, 0.07%, 0.08%, 0.1% or 0.15%; or, the content of Cu is preferably less than 0.08%, but It is not 0, such as 0.05%, 0.07% or 0.08%; the percentage is the mass percentage of the total mass of the neodymium iron boron magnet material.

In the present invention, the method of adding Cu preferably includes adding during smelting and/or adding during grain boundary diffusion. When the Cu is added during the grain boundary diffusion, the content of Cu added during the grain boundary diffusion is preferably 0.03 to 0.15%, such as 0.05%, and the percentage is the mass percentage of the total mass of the neodymium iron boron magnet material When the Cu is added when the grain boundary is diffused, the Cu is preferably added in the form of a PrCu alloy, wherein the mass percentage of the Cu in the PrCu is preferably 0.1-17%.

In the present invention, the content of B is preferably 0.97-1.1%, such as 0.99% or 1%, and the percentage is the mass percentage of the total mass of the neodymium iron boron magnet material.

In the present invention, the content of Fe is preferably 65 to 79.5%, for example, 65.4%, 67.28%, 67.31%, 67.53%, 67.67%, 67.7%, 67.74%, 68.76%, 68.91% or 69%. It is the mass percentage of the total mass of the neodymium iron boron magnet material.

In the present invention, the neodymium iron boron magnet material preferably includes the following components by mass: R: 29 to 32.6%; R includes R1 and R2, said R1 includes Nd and Dy, and the amount of Dy is 0.3 % Or less but not 0, the R1 is a rare earth element added during smelting, the content of R2 is 0.2-1%, the R2 includes Tb, and the R2 is a rare earth element added during grain boundary diffusion; Co: 0.05～0.45%; M: 0.08～0.35%, the type of M includes one or more of Ti, Nb and Zr; Cu: 0.05～0.15%; B: 0.97～1.1%; Fe: 65～79. %; The percentage is the mass percentage of the content of each component in the total mass of the neodymium iron boron magnet material; the neodymium iron boron magnet material includes Nd ₂ Fe _l4 B crystal grains and its shell layer, adjacent to the Nd ₂ Fe _l4 B The two-grain grain boundary and the grain boundary triangle area of the crystal grains; wherein the heavy rare earth elements in R1 are mainly distributed in the Nd ₂ Fe ₁₄ B crystal grains, and R2 is mainly distributed in the shell layer, the two-grain grain boundary and the grain boundary triangle area, The area ratio of the triangular area of the grain boundary is 1.96 to 2.99%; the continuity of the grain boundary of the two-grain grain boundary is more than 97%; the mass ratio of C and O in the triangular area of the grain boundary is 0.41 to 0.49 %; The mass ratio of C and O in the two-grain boundary is 0.3-0.4%; the two-grain boundary contains a new phase, and the chemical composition of the new phase is: R _x (Fe+Co ) _100-xyz Cu _y M _z , x is 78.89-80.8, y is 0.55-0.66, z is 0.02-0.06; the area of the new phase in the two-grain boundary is equal to the total area of the two-grain boundary The area ratio is 0.21 to 2.6%.

In the present invention, the neodymium iron boron magnet material preferably includes the following components by mass: R: 29-31%; R includes R1 and R2, said R1 includes Nd and Dy, and the amount of Dy is 0.1 ~0.2%, the R1 is a rare earth element added during smelting, the content of R2 is 0.2-0.8%, the R2 includes Tb, and the R2 is a rare earth element added during grain boundary diffusion; Co: 0.05~0.4 %; M: 0.1 to 0.15%, the type of M includes one or more of Ti, Nb and Zr; Cu: 0.08% or less but not 0; B: 0.97 to 1.1%; Fe: 65 to 79.5 %; The percentage is the mass percentage of the content of each component in the total mass of the neodymium iron boron magnet material; the neodymium iron boron magnet material includes Nd ₂ Fe _l4 B crystal grains and its shell layer, adjacent to the Nd ₂ Fe _l4 B The two-grain grain boundary and the grain boundary triangle area of the crystal grains; wherein the heavy rare earth elements in R1 are mainly distributed in the Nd ₂ Fe ₁₄ B crystal grains, and R2 is mainly distributed in the shell layer, the two-grain grain boundary and the grain boundary triangle area, The area ratio of the triangular area of the grain boundary is 1.96-2.8%; the continuity of the grain boundary of the two-grain boundary is more than 98%; the mass ratio of C and O in the triangular area of the grain boundary is 0.41 to 0.48 %; The mass ratio of C and O in the two-grain boundaries is 0.34 to 0.4%; the two-grain boundaries contain a new phase, and the chemical composition of the new phase is: R _x (Fe+Co ) _100-xyz Cu _y M _z , x is 78.89-80.8, y is 0.55-0.66, z is 0.02-0.06; the area of the new phase in the two-grain boundary is equal to the total area of the two-grain boundary The area ratio is 0.34 to 2.55%.

In a preferred embodiment of the present invention, the neodymium iron boron magnet material includes the following components by mass content: R1 is Nd 28.6%, Dy 0.05%, Pr 0.1%, and R1 is a rare earth element added during smelting; R2 is Tb 1%, the R2 is the rare earth element added during grain boundary diffusion; Co 0.05%; Ti 0.05%; Nb 0.2%; Cu 0.05%; B 0.99% and Fe 68.91%, the percentage is the content of each component The mass percentage of the total mass of the neodymium iron boron magnet material; the neodymium iron boron magnet material includes Nd ₂ Fe _l4 B crystal grains and its shell layer, _{two grain boundaries adjacent to the Nd 2} Fe _l4 B crystal grains and crystal grains Boundary triangle area; wherein the heavy rare earth elements in R1 are mainly distributed in Nd ₂ Fe ₁₄ B crystal grains, and R2 is mainly distributed in the shell layer, the two-grain boundary and the grain boundary triangle area, and the area of the crystal boundary triangle area occupies The ratio is 1.98%; the grain boundary continuity of the two-grain boundary is 98.13%; the mass ratio of C and O in the triangular region of the grain boundary is 0.47%; the mass of C and O in the two-grain boundary The proportion is 0.35%; the two-grain boundary contains a new phase, and its chemical composition is R _79.43 (Fe+Co) _19.92 Cu _0.63 M _0.02 , and R is one or more of Nd, Dy, Pr and Tb, M is Ti and Nb; the ratio of the area of the new phase in the two-grain boundary to the total area of the two-grain boundary is 1.87%.

In a preferred embodiment of the present invention, the neodymium iron boron magnet material includes the following components by mass content: R1 is Nd 28.6%, Dy 0.1%, Pr 0.2%, and R1 is a rare earth element added during smelting; R2 is Tb 0.9%, the R2 is the rare earth element added during grain boundary diffusion; Co 0.05%; Ti 0.1%; Cu 0.05%; B 1% and Fe 69%, the percentages are the content of each component in the neodymium iron The mass percentage of the total mass of the boron magnet material; the neodymium iron boron magnet material comprises Nd ₂ Fe _l4 B crystal grains and its shell layer, _{two grain boundaries adjacent to the Nd 2} Fe _l4 B crystal grains and a grain boundary triangle region; The heavy rare earth elements in R1 are mainly distributed in Nd ₂ Fe ₁₄ B crystal grains, and R2 is mainly distributed in the shell layer, the two-grain boundary and the grain boundary triangle area, and the area of the grain boundary triangle area accounts for 2.05% The continuity of the grain boundary of the two-grain grain boundary is 97.92%; the mass ratio of C and O in the triangular region of the grain boundary is 0.48%; the mass ratio of C and O in the two-grain grain boundary is 0.3 %; the two-grain boundary contains a new phase, its chemical composition is R _78.89 (Fe+Co) _20.49 Cu _0.58 M _0.04 , R is one or more of Nd, Dy, Pr and Tb, and M is Ti; The ratio of the area of the new phase in the two-particle grain boundary to the total area of the two-particle grain boundary is 2.34%.

In a preferred embodiment of the present invention, the neodymium iron boron magnet material includes the following components by mass: R1 is Nd 28.6%, Dy 0.08%, R1 is rare earth element added during smelting; R2 is Tb 0.9 %, the R2 is the rare earth element added during grain boundary diffusion; Co 0.1%; Ti 0.3%; Nb 0.05%; Ga 0.05%; Cu 0.06%; B 1.1% and Fe 68.76%, the percentage is the content of each component It accounts for the mass percentage of the total mass of the neodymium iron boron magnet material; the neodymium iron boron magnet material comprises Nd ₂ Fe _l4 B crystal grains and its shell, _{two grain boundaries adjacent to the Nd 2} Fe _l4 B crystal grains and The grain boundary triangle region; wherein the heavy rare earth elements in R1 are mainly distributed in the Nd ₂ Fe ₁₄ B crystal grains, and R2 is mainly distributed in the shell layer, the two-grain grain boundary and the grain boundary triangle region, and the area of the grain boundary triangle region The proportion is 1.96%; the grain boundary continuity of the two-grain boundary is 97.85%; the mass proportion of C and O in the triangular region of the grain boundary is 0.41%; the proportion of C and O in the two-grain grain boundary The mass ratio is 0.36%; the two-grain boundary contains a new phase, its chemical composition is R _80.72 (Fe+Co) _18.68 Cu _0.55 M _0.05 , R is one or more of Nd, Dy and Tb, M It is one or more of Ti, Nb and Ga; the ratio of the area of the new phase in the two-grain boundary to the total area of the two-grain boundary is 1.15%.

In a preferred embodiment of the present invention, the neodymium iron boron magnet material includes the following components by mass: R1 is Nd 29.9%, Dy 0.1%, the R1 is the rare earth element added during smelting; R2 is Tb 0.8 %, Pr 0.1%, the R2 is a rare earth element added during grain boundary diffusion; Co 0.1%; Zr 0.2%; Al 0.2%; Cu added during smelting is 0.03%, and Cu added during grain boundary diffusion is 0.05% B 0.99% and Fe 67.53%, the percentages are the mass percentages of the content of each component in the total mass of the neodymium iron boron magnet material; the neodymium iron boron magnet material includes Nd ₂ Fe _l4 B crystal grains and its shell layer, adjacent The two-grain boundary and the triangular area of the grain boundary of the Nd ₂ Fe _l4 B crystal grains; wherein the heavy rare earth elements in R1 are mainly distributed in the Nd ₂ Fe ₁₄ B crystal grains, and R2 is mainly distributed in the shell layer and the two-grain crystal grains. The area of the grain boundary and the grain boundary triangle area accounts for 1.96%; the grain boundary continuity of the two-grain grain boundary is 97.85%; the mass ratio of C and O in the grain boundary triangle area The mass ratio of C and O in the two-grain boundary is 0.36%; the two-grain boundary contains a new phase, and its chemical composition is R _79.21 (Fe+Co) _20.11 Cu _0.66 M _0.02 , R It is one or more of Nd, Dy, Pr and Tb, and M is Zr; the ratio of the area of the new phase in the two-grain boundary to the total area of the two-grain boundary is 2.55%.

In a preferred embodiment of the present invention, the neodymium iron boron magnet material includes the following components by mass: R1 is Nd 30.4%, Dy 0.05%, R1 is rare earth element added during smelting; R2 is Tb 0.8 %, Dy 0.1%, the R2 is the rare earth element added during the grain boundary diffusion; Co 0.2%; Zr 0.08%; Cu 0.1%; B 0.99% and Fe 67.28%, the percentage is that the content of each component accounts for the neodymium iron The mass percentage of the total mass of the boron magnet material; the neodymium iron boron magnet material comprises Nd ₂ Fe _l4 B crystal grains and its shell layer, _{two grain boundaries adjacent to the Nd 2} Fe _l4 B crystal grains and a grain boundary triangle region; The heavy rare earth elements in R1 are mainly distributed in the Nd ₂ Fe ₁₄ B crystal grains, and R2 is mainly distributed in the shell layer, the two-grain grain boundary and the grain boundary triangle area, and the area of the grain boundary triangle area accounts for 2.78% The grain boundary continuity of the two-grain grain boundary is 98.54%; the mass ratio of C and O in the triangular region of the grain boundary is 0.48%; the mass ratio of C and O in the two-grain grain boundary is 0.34 %; the two-grain boundary contains a new phase, its chemical composition is R _80.09 (Fe+Co) _19.22 Cu _0.65 M _0.04 , R is one or more of Nd, Dy and Tb, and M is Zr; The ratio of the area of the new phase in the two-grain boundaries to the total area of the two-grain boundaries is 0.85%.

In a preferred embodiment of the present invention, the neodymium iron boron magnet material includes the following components by mass: R1 is Nd 29.9%, Dy 0.15%, R1 is rare earth element added during smelting; R2 is Tb 0.6 %, the R2 is the rare earth element added during grain boundary diffusion; Co 0.2%; Zr 0.35%; Cu 0.1%; B 1% and Fe 67.7%, the percentage is that the content of each component accounts for the total neodymium iron boron magnet material The mass percentage of the mass; the neodymium iron boron magnet material includes Nd ₂ Fe _l4 B crystal grains and its shell layer, _{two grain boundaries adjacent to the Nd 2} Fe _l4 B crystal grains and the grain boundary triangle region; wherein the R1 in The heavy rare earth elements are mainly distributed in Nd ₂ Fe ₁₄ B crystal grains, and R2 is mainly distributed in the shell layer, the two-grain boundary and the grain boundary triangle area, and the area of the grain boundary triangle area accounts for 2.73%; The grain boundary continuity of the grain boundary is 98.01%; the mass ratio of C and O in the triangular region of the grain boundary is 0.41%; the mass ratio of C and O in the two-grain grain boundary is 0.37%; The grain boundary contains a new phase, its chemical composition is R _79.04 (Fe+Co) _20.31 Cu _0.61 M _0.04 , R is one or more of Nd, Dy and Tb, and M is Zr; the new phase is The ratio of the area in the two-grain boundary to the total area of the two-grain boundary is 1.33%.

In a preferred embodiment of the present invention, the neodymium iron boron magnet material includes the following components by mass: R1 is Nd 29.9%, Dy 0.2%, R1 is rare earth element added during smelting; R2 is Tb 0.6 %, the R2 is the rare earth element added during grain boundary diffusion; Co 0.3%; Nb 0.05%; Ga 0.01%; Al 0.1%; Cu 0.07%; B 1.1% and Fe 67.67%, the percentage is the content of each component The mass percentage of the total mass of the neodymium iron boron magnet material; the neodymium iron boron magnet material includes Nd ₂ Fe _l4 B crystal grains and its shell layer, _{two grain boundaries adjacent to the Nd 2} Fe _l4 B crystal grains and crystal grains Boundary triangle area; wherein the heavy rare earth elements in R1 are mainly distributed in the Nd ₂ Fe ₁₄ B crystal grains, and R2 is mainly distributed in the shell layer, the two-grain boundary and the crystal boundary triangle area, and the area of the crystal boundary triangle area occupies The ratio is 2.73%; the grain boundary continuity of the two-grain boundary is 98.07%; the mass ratio of C and O in the triangular region of the grain boundary is 0.49%; the mass of C and O in the two-grain grain boundary The proportion is 0.35%; the two-grain boundary contains a new phase, its chemical composition is R _79.76 (Fe+Co) _19.64 Cu _0.58 M _0.02 , R is one or more of Nd, Dy and Tb, and M is Nb and Ga; the ratio of the area of the new phase in the two-grain boundaries to the total area of the two-grain boundaries is 1.21%.

In a preferred embodiment of the present invention, the neodymium iron boron magnet material includes the following components by mass: R1 is Nd 30.4%, Dy 0.05%, R1 is rare earth element added during smelting; R2 is Tb 0.3 %, the R2 is the rare earth element added during grain boundary diffusion; Co 0.4%; Nb 0.2%; Cu added during smelting is 0.12%, Cu added during grain boundary diffusion is 0.03; B is 0.99% and Fe 67.31%, The percentage is the mass percentage of the content of each component in the total mass of the neodymium iron boron magnet material; the neodymium iron boron magnet material comprises Nd ₂ Fe ₁₄ B crystal grains and its shell layer, adjacent to the Nd ₂ Fe ₁₄ B crystal grains The two-grain boundary and the triangular area of the grain boundary; wherein the heavy rare earth elements in R1 are mainly distributed in the Nd ₂ Fe _l4 B crystal grains, and R2 is mainly distributed in the shell layer, the two-grain boundary and the triangular area of the grain boundary. The area ratio of the grain boundary triangle region is 2.36%; the grain boundary continuity of the two-grain grain boundary is 98.12%; the mass ratio of C and O in the grain boundary triangle region is 0.48%; the two-grain crystal The mass ratio of C and O in the boundary is 0.38%; the two-grain boundary contains a new phase with a chemical composition of R _79.71 (Fe+Co) _19.65 Cu _0.62 M _0.02 , and R is one of Nd, Dy, and Tb. One or more kinds, M is Nb; the ratio of the area of the new phase in the two-particle grain boundary to the total area of the two-particle grain boundary is 1.08%.

In a preferred embodiment of the present invention, the neodymium iron boron magnet material includes the following components by mass: R1 is Nd 32.1%, Dy 0.3%, R1 is rare earth element added during smelting; R2 is Tb 0.2 %, the R2 is the rare earth element added during grain boundary diffusion; Co 0.45%; Nb 0.3%; Cu 0.15%; B 1.1% and Fe 65.4%, the percentage is that the content of each component accounts for the total neodymium iron boron magnet material The mass percentage of the mass; the neodymium iron boron magnet material includes Nd ₂ Fe _l4 B crystal grains and its shell layer, _{two grain boundaries adjacent to the Nd 2} Fe _l4 B crystal grains and the grain boundary triangle region; wherein the R1 in The heavy rare earth elements are mainly distributed in the Nd ₂ Fe ₁₄ B crystal grains, and R2 is mainly distributed in the shell layer, the grain boundary of the two grains and the grain boundary triangle area, and the area of the grain boundary triangle area accounts for 2.99%; The grain boundary continuity of the grain boundary is 98.03%; the mass proportion of C and O in the triangular region of the grain boundary is 0.45%; the mass proportion of C and O in the two grain boundary is 0.4%; The grain boundary contains a new phase, its chemical composition is R _80.18 (Fe+Co) _19.16 Cu _0.62 M _0.04 , R is one or more of Nd, Dy and Tb, and M is Nb; the new phase is The ratio of the area in the two-grain boundary to the total area of the two-grain boundary is 0.21%.

In a preferred embodiment of the present invention, the neodymium iron boron magnet material includes the following components by mass: R1 is Nd 29.9%, Dy 0.2%, R1 is rare earth element added during smelting; R2 is Tb 0.6 %, the R2 is the rare earth element added during grain boundary diffusion; Co 0.3%; Nb 0.05%; Ga 0.01%; Al 0.03%; Cu 0.07%; B 1.1% and Fe 67.74%, the percentage is the content of each component The mass percentage of the total mass of the neodymium iron boron magnet material; the neodymium iron boron magnet material includes Nd ₂ Fe _l4 B crystal grains and its shell layer, _{two grain boundaries adjacent to the Nd 2} Fe _l4 B crystal grains and crystal grains Boundary triangle area; wherein the heavy rare earth elements in R1 are mainly distributed in Nd ₂ Fe ₁₄ B crystal grains, and R2 is mainly distributed in the shell layer, the two-grain boundary and the grain boundary triangle area, and the area of the crystal boundary triangle area occupies The ratio is 2.54%; the grain boundary continuity of the two-grain boundary is 98.18%; the mass ratio of C and O in the triangular region of the grain boundary is 0.44%; the mass of C and O in the two-grain boundary The proportion is 0.35%; the two-grain boundary contains a new phase, its chemical composition is R _79.4 (Fe+Co) _19.94 Cu _0.64 M _0.02 , R is one or more of Nd, Dy and Tb, and M is Nb and Ga; the ratio of the area of the new phase in the two-grain boundary to the total area of the two-grain boundary is 0.34%.

The neodymium iron boron magnet material provided by the present invention reasonably controls the total rare earth content TRE, Co, Cu and the content range of M (Ti, Nb, Zr, etc.) elements, and combines the specific feeding timing of heavy rare earth elements to make more miscellaneous phases. Distributed in the grain boundary of the two grains, rather than agglomerated in the triangular area of the grain boundary, so that the continuity of the grain boundary is improved, and the area of the triangular area of the grain boundary is reduced, which is beneficial to obtain a higher density, thereby increasing the magnet remanence Br; It also promotes the Tb element to be mainly uniformly distributed in the grain boundary and the main phase shell, which improves the coercivity Hcj of the magnet.

The invention also provides an application of the neodymium iron boron magnet material described above in the preparation of magnetic steel.

Among them, the magnetic steel is preferably 54SH, 54UH, 56SH magnetic steel.

On the basis of conforming to common knowledge in the field, the above-mentioned preferred conditions can be combined arbitrarily to obtain preferred examples of the present invention.

The reagents and raw materials used in the present invention are all commercially available.

The positive progress effect of the present invention is that the neodymium iron boron magnet material of the present invention can be used in comparison with the existing neodymium iron boron through the combination of the specific content of multiple elements, under the premise of only adding a small amount of Co and a small amount of heavy rare earth elements. On the basis of magnet materials, the proportion of impurity phases (rare earth oxides, rare earth carbides) in the two-grain boundary phase is increased, and new phases are formed in the two-grain boundary; correspondingly, the two-grain boundary Continuity, reducing the proportion of phases in the grain boundary triangle area, and correspondingly reducing the area of the grain boundary triangle area. This improves the compactness of the NdFeB magnet material, and also promotes the uniform distribution of the Tb element in the grain boundary and the main phase shell layer, and improves the remanence Br, the coercive force Hcj, and the corresponding temperature of the NdFeB magnet material. stability.

Description of the drawings

FIG. 1 is an EPMA microstructure diagram of the neodymium iron boron magnet material of Example 4. FIG. The point indicated by arrow 1 in the figure is the _{new phase of R x} (Fe+Co) _100-xyz Cu _y M _z contained in the grain boundary of the two grains, the position indicated by arrow 2 is the triangular area of the grain boundary, and the arrow 3 indicates The position is the main phase _{of Nd 2} Fe _{l4 B.}

Detailed ways

The present invention will be further described by way of examples below, but the present invention is not limited to the scope of the described examples. In the following examples, the experimental methods without specific conditions are selected according to conventional methods and conditions, or according to the product specification.

1. The raw material compositions of the neodymium-iron-boron magnet materials of Examples 1 to 10 and Comparative Examples 1 to 4 of the present invention are shown in Table 1 below.

Table 1 The formula and content of the raw material composition of the neodymium iron boron magnet material (wt%)

Note: "/" means that the element is not contained. The wt% is the mass percentage.

2. Preparation method of neodymium iron boron magnet material in embodiment 1

(1) Melting and casting process: According to the formula in Table 1, add the prepared R2 (R2 in Examples 4 and 8 is added in the form of PrCu, and the content of Cu added in the grain boundary diffusion step in Examples 4 and 8 Respectively 0.05wt% and 0.03wt%, Cu in the smelting step, the content of addition is 0.03wt% and 0.12wt%) other raw materials are put into the alumina crucible, in the high-frequency vacuum melting furnace with 0.05Pa Vacuum melting is performed under vacuum and 1500°C. Then, argon gas is introduced into the intermediate frequency vacuum induction rapid-solidifying belt spinning furnace to perform casting, and then the alloy is quenched to obtain alloy flakes.

(2) Hydrogen breaking and powder making process: vacuum the hydrogen breaking furnace where the quench alloy is placed at room temperature, and then pass hydrogen with a purity of 99.9% into the hydrogen breaking furnace, maintain the hydrogen pressure at 90kPa, and fully absorb hydrogen. , The temperature is raised while vacuuming to fully dehydrogenate, and then cooling is performed to take out the powder after hydrogen breakage and pulverization. Among them, the temperature for hydrogen absorption is room temperature, and the temperature for dehydrogenation is 550°C.

(3) Airflow milling process: Under nitrogen atmosphere, the powder after hydrogen pulverization is pulverized by airflow milling for 3 hours under the condition of 0.6 MPa in the pulverizing chamber to obtain fine powder.

(4) Molding process: the powder after passing through the air-flow film is molded in a magnetic field strength of 1.5T or more.

(5) Sintering process: each molded body is moved to a sintering furnace for sintering, sintered under a vacuum of less than 0.5 Pa, and sintered at 1030-1090°C for 2 to 5 hours to obtain a sintered body.

(6) Grain boundary diffusion process: after the surface of the sintered body is purified, R2 (such as Tb alloy or fluoride, Dy alloy or fluoride and PrCu alloy, The diffusion step is added at the same time) coating on the surface of the sintered body and diffusing at a temperature of 850°C for 5-15 hours, then cooling to room temperature, and then performing low-temperature tempering treatment at a temperature of 460-560°C for 1-3 hours.

The parameters in the preparation methods of the neodymium iron boron magnet materials in Examples 2-10 and Comparative Examples 1-4 are the same as those in Example 1.

3. Component determination: The neodymium iron boron magnet materials in Examples 1-10 and Comparative Examples 1-4 were measured using a high-frequency inductively coupled plasma emission spectrometer (ICP-OES). The test results are shown in Table 2 below.

Table 2 Composition and content of neodymium iron boron material (wt%)

Effect Example 1

The microstructure and magnetic properties of the neodymium-iron-boron magnet materials in Examples 1-10 and Comparative Examples 1-4 are tested as follows.

1. Magnetic performance test: The sintered magnet is tested on the magnetic performance of the PFM-14 magnetic performance measuring instrument from British Hirs company. The tested magnetic properties include the remanence at 20℃ and 120℃, and the coercivity at 20℃ and 120℃. , And the corresponding temperature coefficient of remanence. Among them, the formula for calculating the temperature coefficient of remanence is: (Br _{high temperature-} Br _{normal temperature} )/(Br _{normal temperature} (high temperature-normal temperature))×100%, and the test results are shown in Table 3 below.

2. FE-EPMA detection: polishing the vertical orientation surface of the neodymium iron boron magnet material, using the field emission electron probe microanalyzer (FE-EPMA) (JEOL, 8530F) to detect. Test the area ratio of the grain boundary triangle area, the continuity of the two grain boundaries, the mass ratio of C and O, and the new phase. The test results are shown in Table 3 below.

The continuity of the two-grain boundary is calculated based on EPMA's backscattering picture; the mass proportion of C and O in the two-grain boundary and the triangular area of the grain boundary and the new phase are measured by the elemental analysis of EPMA.

The area ratio of the grain boundary triangle area (%) refers to the ratio of the area of the grain boundary triangle area to the total area of "grains and grain boundaries".

The continuity of the two grain boundaries (%) refers to the length occupied by the phases other than voids in the grain boundaries (phases such as B-rich phase, rare-earth-rich phase, rare-earth oxide, rare-earth carbide, etc.) and total The ratio of the grain boundary length.

The mass ratio of C and O in the grain boundary triangle area (%) refers to the ratio of the mass of C and O in the grain boundary triangle area to the total mass of all elements in the grain boundary.

The mass ratio of C and O in the two-grain boundary (%) refers to the ratio of the mass of C and O in the two-grain boundary to the total mass of all elements in the grain boundary.

The area ratio (%) of the new phase in the two-grain boundary refers to the ratio of the area of the new phase in the two-grain boundary to the total area of the two-grain boundary.

table 3

Note: "×" means that the two-grain boundary phase does not contain a new phase with a chemical composition of R _x (Fe+Co) _100-xyz Cu _y M _z .

It can be seen from the above Table 3 that the present invention can achieve a level equivalent to the current addition of a large amount of Co and heavy rare earth elements by adding a small amount of Co and heavy rare earth elements. In addition, due to the high content of rare earths in the grain boundaries, C and O are more distributed in the grain boundaries and exist in the form of rare earth carbides and rare earth oxides, respectively. According to the difference of the "mass proportion of C and O in the triangular region of the grain boundary (%)" minus the "mass proportion of C and O (%) in the grain boundary of the two grains" in Examples 1-10 compared to the comparative example 1～4 are all reduced, it can be concluded that the miscellaneous phases (rare earth carbides and rare earth oxides) migrate from the triangular area of the grain boundary to the two-grain boundary, and the formation of new phases, which explains the mechanism of the two-grain boundary Reasons for continuity improvement.

Effect Example 2

As shown in FIG. 1, it is the EPMA microstructure diagram of the neodymium iron boron magnet material prepared in Example 4. _{The point indicated by arrow 1 in the figure is the new phase of R x} (Fe+Co) _100-xyz Cu _y M _z contained in the two-grain grain boundary (light gray area), and the position indicated by arrow 2 is the triangular area of the grain boundary (Silver white area), the position indicated by arrow 3 is the _{main phase of Nd 2} Fe _l4 B (dark gray area). Combining the data in Table 3, it can be further seen that the area of the grain boundary triangle region is smaller than that of conventional magnet materials.

Claims

A raw material composition of neodymium iron boron magnet material, characterized in that it comprises the following components by mass content: R: 28-33%;

The R is a rare earth element, R includes R1 and R2, the R1 is a rare earth element added during smelting, and the R1 includes Nd and Dy;

The R2 is a rare earth element added during grain boundary diffusion, the R2 includes Tb, and the content of the R2 is 0.2-1%;

Co: <0.5%, but not 0;

M: ≤0.4%, but not 0, the type of M includes one or more of Ti, Ni, V, Nb, Ta, Cr, Mo, W, Mn, Zr, Hf, and Ag;

Cu: ≤0.15%, but not 0;

B: 0.9～1.1%;

Fe: 60-70%; the percentage is the mass percentage of the content of each component in the total mass of the raw material composition.
The raw material composition of claim 1, wherein the content of R in the raw material composition is 29 to 32.6%, preferably 29 to 31%, and the percentage is based on the total of the raw material composition Mass percentage of mass;

And/or, in R1 of the raw material composition, the Nd content is 28 to 32.5%, and the percentage is a mass percentage of the total mass of the raw material composition;

And/or, in the R1, the content of the Dy is less than 0.3%, but not 0, preferably 0.1 to 0.2%, and the percentage is the mass percentage of the total mass of the raw material composition;

And/or, said R1 also includes one or more of Pr, Ho, Tb, Gd and Y;

And/or, when the R1 contains Pr, the addition form of Pr is in the form of PrNd, or in the form of a mixture of pure Pr and pure Nd, or, as a joint addition of "PrNd, a mixture of pure Pr and pure Nd" ; When added in the form of PrNd, Pr:Nd is preferably 25:75 or 20:80; when added in the form of a mixture of pure Pr and Nd or a combination of PrNd, pure Pr and Nd, The content of the Pr is preferably 0.1 to 2 wt%, wherein the percentage is the mass percentage of the total mass of the raw material composition;

Wherein, when the R1 includes Ho, the content of Ho is preferably 0.1-0.2%, and the percentage is the mass percentage of the total mass of the raw material composition;

Wherein, when the R1 includes Gd, the content of Gd is preferably 0.1-0.2%, and the percentage is the mass percentage of the total mass of the raw material composition;

Wherein, when the R1 includes Y, the content of Y is preferably 0.1-0.2%, and the percentage is the mass percentage of the total mass of the raw material composition;

And/or, the content of R2 is 0.2-0.9%, preferably 0.2-0.8%, and the percentage is the mass percentage of the total mass of the raw material composition;

And/or, in the R2, the content of Tb is 0.2-0.9%, preferably 0.2-0.8%, and the percentage is the mass percentage of the total mass of the raw material composition

And/or, said R2 also includes one or more of Pr, Dy, Ho and Gd;

Wherein, when the R2 includes Pr, the content of the Pr is preferably 0.2% or less, but not 0, and the percentage is the mass percentage of the total mass of the raw material composition;

Wherein, when the R2 includes Dy, the content of Dy is preferably less than 0.3%, but not 0, and the percentage is the mass percentage of the total mass of the raw material composition;

Wherein, when the R2 includes Ho, the content of Ho is preferably 0.2% or less, but not 0, and the percentage is the mass percentage of the total mass of the raw material composition;

Wherein, when the R2 includes Gd, the content of Gd is preferably less than 0.2%, but not 0, and the percentage is the mass percentage of the total mass of the raw material composition;

And/or, the content of Co is 0.45% or less, but not 0, preferably 0.05 to 0.4%, and the percentage is the mass percentage of the total mass of the raw material composition;

And/or, the content of M is 0.08-0.35%, preferably 0.1-0.15%, and the percentage is the mass percentage of the total mass of the raw material composition;

And/or, the type of M is one or more of Ti, Zr, Nb, Ni, V, Ta, Cr, Mo, W, Mn, Hf and Ag;

Wherein, when the M contains Ti, the content of Ti is preferably 0.05 to 0.3%, and the percentage is the mass percentage of the total mass of the raw material composition;

Wherein, when the M contains Zr, the content of Zr is preferably 0.08-0.35%, and the percentage is the mass percentage of the total mass of the raw material composition;

Wherein, when the M contains Nb, the content of Nb is preferably 0.05 to 0.3%, and the percentage is the mass percentage of the total mass of the raw material composition;

And/or, in the raw material composition, the M further includes one or more of Bi, Sn, Zn, Ga, In, Au and Pb;

Wherein, when the M element contains Ga, the content of Ga is preferably more than 0.2%, or less than 0.01%, but not 0, and the percentage is the mass percentage of the total mass of the raw material composition;

Wherein, when the M element contains Ga, and Ga≥0.2%, preferably, Ti+Nb≤0.07% in the composition of the M element, and the percentage is the mass percentage of the total mass of the raw material composition;

And/or, the raw material composition further includes Al; the content of Al is preferably less than 0.2%, but not 0, more preferably 0.03 to 0.2%, and the percentage is based on the total of the raw material composition Mass percentage of mass;

Wherein, when the M contains Ga and Ga≤0.01%, preferably, in the composition of the M element, Al+Ga+Cu≤0.11%, and the percentage is the mass percentage of the total mass of the raw material composition;

And/or, the Cu content is 0.05-0.15%, or less than 0.08%, but not 0, and the percentage is the mass percentage of the total mass of the raw material composition;

And/or, the way of adding Cu includes adding during smelting and/or adding during grain boundary diffusion;

Wherein, when the Cu is added during the grain boundary diffusion, the content of Cu added during the grain boundary diffusion is preferably 0.05 to 0.15%, and the percentage is the mass percentage of the total mass of the raw material composition;

Wherein, when the Cu is added when it diffuses at the grain boundary, the Cu is preferably added in the form of a PrCu alloy; wherein the mass percentage of the Cu and the PrCu is preferably 0.1-17%;

And/or, the content of B is 0.97-1.1%, and the percentage is the mass percentage of the total mass of the raw material composition;

And/or, the content of Fe is 65 to 79.5%, and the percentage is the mass percentage of the total mass of the raw material composition.
The raw material composition of claim 1 or 2, wherein the raw material composition of the neodymium iron boron magnet material includes the following components by mass: R: 29 to 32.6%; R includes R1 and R2, so The R1 includes Nd and Dy, the amount of Dy is 0.3% or less, but not 0, the R1 is a rare earth element added during smelting, the content of R2 is 0.2 to 1%, and the R2 includes Tb, The R2 is a rare earth element added during grain boundary diffusion; Co: 0.05-0.45%; M: 0.08-0.35%, the type of M includes one or more of Ti, Nb and Zr; Cu: 0.05- 0.15%; B: 0.97 to 1.1%; Fe: 65 to 79.5%; the percentage is the mass percentage of the content of each component in the total mass of the raw material composition;

Alternatively, the raw material composition of the neodymium iron boron magnet material includes the following components by mass content: R: 29-31%; R includes R1 and R2, said R1 includes Nd and Dy, and the amount of Dy is 0.1- 0.2%, the R1 is a rare earth element added during smelting, the content of R2 is 0.2-0.8%, the R2 includes Tb, and the R2 is a rare earth element added during grain boundary diffusion; Co: 0.05-0.4% ; M: 0.1 to 0.15%, the type of M includes one or more of Ti, Nb and Zr; Cu: less than 0.08% but not 0; B: 0.97 to 1.1%; Fe: 65 to 79.5% ; Percentage is the mass percentage of the content of each component in the total mass of the raw material composition.
A preparation method of neodymium iron boron magnet material, which adopts the raw material composition according to any one of claims 1 to 3. The preparation method is a diffusion method, wherein the R1 element is added in the smelting step, The R2 element is added in the grain boundary diffusion step.
The preparation method according to claim 4, wherein the preparation method comprises the following steps: the elements other than R2 in the raw material composition of the neodymium iron boron magnet material are obtained by smelting, powdering, molding, and sintering Sintered body, and then diffuse the mixture of the sintered body and the R2 through the grain boundary;

Wherein, the smelting operation is preferably to smelt and cast the elements other than R2 in the neodymium iron boron magnet material using an ingot process and a quick-setting sheet process to obtain an alloy sheet;

The melting temperature is preferably 1300 to 1700°C, more preferably 1450 to 1550°C;

Wherein, the pulverizing preferably includes hydrogen crushing pulverizing and/or jet milling pulverizing;

The hydrogen pulverization preferably includes hydrogen absorption, dehydrogenation and cooling treatment; the temperature of hydrogen absorption is preferably 20 to 200°C; the temperature of dehydrogenation is preferably 400 to 650°C, and more It is preferably 500-550°C; the pressure of the hydrogen absorption is preferably 50-600kPa;

The airflow milling powder preferably performs airflow milling under the conditions of 0.1-2MPa, more preferably 0.5-0.7MPa; the airflow in the airflow milling powder is preferably nitrogen; the airflow mill The milling time is preferably 2 to 4 hours;

Wherein, the molding is preferably a magnetic field molding method, and the magnetic field strength of the magnetic field molding method is 1.5T or more;

Wherein, the sintering is preferably performed under the condition that the vacuum degree is lower than 0.5 Pa;

The sintering temperature is preferably 1000 to 1200°C, more preferably 1030 to 1090°C;

The sintering time is preferably 0.5-10h, more preferably 2-5h;

Wherein, before the grain boundary diffusion, it preferably further includes the coating operation of the R2;

Said R2 is preferably coated in the form of fluoride or low melting point alloy, such as Tb fluoride; when Dy is also contained, preferably, Dy is coated in the form of Dy fluoride;

When Pr is also included, preferably, Pr is added in the form of a PrCu alloy;

When the R2 contains Pr and Pr participates in the grain boundary diffusion in the form of a PrCu alloy, preferably, in the PrCu alloy, the mass ratio of the Cu and the PrCu alloy is preferably 0.1-17%; preferably Preferably, the timing of adding the Cu in the preparation method is a grain boundary diffusion step, or it is added at the same time as the smelting step and the grain boundary diffusion step;

Wherein, the temperature of the grain boundary diffusion is preferably 800-1000°C;

The time for the grain boundary diffusion is preferably 5-20h, more preferably 5-15h;

Wherein, after the grain boundary diffuses, it is preferable to perform low-temperature tempering treatment; the temperature of the low-temperature tempering treatment is preferably 460-560°C; and the time of the low-temperature tempering treatment is preferably 1 to 3 hours.
A neodymium iron boron magnet material prepared by the preparation method according to claim 4 or 5.
A neodymium iron boron magnet material, characterized in that it includes the following components by mass content: R: 28-33%; said R includes R1 and R2, said R1 includes Nd and Dy, and said R2 includes Tb; The content of R2 is 0.2～1%;

Co: <0.5%, but not 0;

M: ≤0.4%, but not 0, the type of M includes one or more of Ti, Ni, V, Nb, Ta, Cr, Mo, W, Mn, Zr, Hf, and Ag;

Cu: ≤0.15%, but not 0;

B: 0.9～1.5%;

Fe: 60-70%; the percentage is the mass percentage of the mass of each component to the total mass of the neodymium iron boron magnet material;

The neodymium iron boron magnet material comprises Nd 2 Fe 14 B crystal grains and its shell layer, two grain boundaries adjacent to the Nd 2 Fe 14 B crystal grains and a grain boundary triangle region;

The heavy rare earth elements in R1 are mainly distributed in Nd 2 Fe 14 B crystal grains, and R2 is mainly distributed in the shell layer, the two-grain grain boundary and the grain boundary triangle area, and the area of the grain boundary triangle area is 1.8~ 2.99%;

The grain boundary continuity of the two-grain grain boundary is more than 96%;

The mass ratio of C and O in the triangular region of the grain boundary is 0.4-0.5%; the mass ratio of C and O in the two-grain grain boundary is 0.3-0.5%.
8. The neodymium iron boron magnet material of claim 7, wherein the area ratio of the triangular region of the grain boundary is 1.96 to 2.99%;

And/or, the grain boundary continuity is 97% or more, preferably 98% or more;

And/or, the mass ratio of C and O in the triangular region of the grain boundary is 0.41 to 0.49%, preferably 0.41 to 0.48%;

And/or, the mass ratio of C and O in the two-particle grain boundary is 0.3-0.4%; preferably 0.34-0.4%;

And/or, the two-particle grain boundary also contains a new phase with a chemical composition of R x (Fe+Co) 100-xyz Cu y M z ; wherein R includes one or more of Nd, Dy and Tb , M includes one or more of Ti, Ni, V, Nb, Ta, Cr, Mo, W, Mn, Zr, Hf, Zn and Ag, x is 78-81; y is 0.4-0.8; z is 0.1 or less, but not 0; wherein, x is preferably 78.89-80.8, y is preferably 0.55-0.66, and z is preferably 0.02-0.06;

Wherein, the ratio of the area of the new phase in the two-particle grain boundary to the total area of the two-particle grain boundary is preferably 0.2-2.6%, more preferably 0.34-2.55%;

And/or, in the neodymium iron boron magnet material, the content of R is 29 to 32.6%, preferably 29 to 31%, and the percentage is a mass percentage of the total mass of the neodymium iron boron magnet material;

And/or, in the R1 of the neodymium iron boron magnet material, the Nd content is 28 to 32.5%, and the percentage is a mass percentage of the total mass of the neodymium iron boron magnet material;

And/or, in R1 of the neodymium iron boron magnet material, the content of Dy is less than 0.3%, but not 0;

And/or, said R1 also includes one or more of Pr, Ho, Tb, Gd and Y;

Wherein, when the R1 contains Pr, the addition form of Pr is preferably in the form of PrNd, or, in the form of a mixture of pure Pr and pure Nd, or, in combination with "PrNd, a mixture of pure Pr and pure Nd" Add; when added in the form of PrNd, Pr:Nd is preferably 25:75 or 20:80; when added in the form of a mixture of pure Pr and Nd or a combination of PrNd, pure Pr and Nd, the The content of Pr is preferably 0.1-2%, and the percentage is the mass percentage of the total mass of the neodymium iron boron magnet material;

And/or, the content of R2 is 0.2-0.9%, preferably 0.2-0.8%, and the percentage is the mass percentage of the total mass of the neodymium iron boron magnet material;

And/or, the content of Tb in the R2 is 0.2% to 0.9%, and the percentage is a mass percentage of the total mass of the neodymium iron boron magnet material;

And/or, said R2 also includes one or more of Pr, Dy, Ho and Gd;

Wherein, when the R2 includes Pr, the content of Pr is preferably 0.2% or less, and the percentage is a mass percentage of the total mass of the neodymium iron boron magnet material;

Wherein, when the R2 includes Dy, the content of Dy is preferably 0.3% or less, and the percentage is a mass percentage of the total mass of the neodymium iron boron magnet material;

And/or, the Co content is 0.45% or less, but not 0, preferably 0.05 to 0.4%, and the percentage is the mass percentage of the total mass of the neodymium iron boron magnet material;

And/or, the content of M is 0.08-0.35%, preferably 0.1-0.15%, and the percentage is the mass percentage of the total mass of the neodymium iron boron magnet material;

And/or, the type of M is one or more of Ti, Zr, Nb, Ni, V, Ta, Cr, Mo, W, Mn, Hf and Ag;

Wherein, when the M contains Ti, the content of Ti is preferably 0.05 to 0.3%;

Wherein, when the M includes Zr, the content of Zr is preferably 0.08-0.35%;

Wherein, when the M contains Nb, the content of Nb is preferably 0.05 to 0.3%, and the percentage is a mass percentage of the total mass of the neodymium iron boron magnet material;

And/or, in the neodymium iron boron magnet material, the M further includes one or more of Bi, Sn, Zn, Ga, In, Au and Pb;

Wherein, when the M contains Ga, the content of Ga is preferably more than 0.2%, or less than 0.01%, but not 0, and the percentage is a mass percentage of the total mass of the neodymium iron boron magnet material;

Wherein, when the M element contains Ga and Ga≥0.2%, preferably, Ti+Nb≤0.07% in the composition of the M element, and the percentage is the mass percentage of the total mass of the neodymium iron boron magnet material;

And/or, the neodymium iron boron magnet material also includes Al; the content of Al is preferably less than 0.2%, but not 0, more preferably 0.03 to 0.2%, and the percentage is based on the neodymium iron The mass percentage of the total mass of boron magnet material;

Wherein, when the M contains Ga and Ga≤0.01%, preferably, in the composition of the M element, Al+Ga+Cu≤0.11%, and the percentage is the mass percentage of the total mass of the neodymium iron boron magnet material;

And/or, the Cu content is 0.05 to 0.15%, or less than 0.08%, but not 0, and the percentage is a mass percentage of the total mass of the neodymium iron boron magnet material;

And/or, the way of adding Cu includes adding during smelting and/or adding during grain boundary diffusion;

When the Cu is added during the grain boundary diffusion, the content of Cu added during the grain boundary diffusion is preferably 0.03 to 0.15%, and the percentage is the mass percentage of the total mass of the neodymium iron boron magnet material;

When the Cu is added when it diffuses at the grain boundary, the Cu is preferably added in the form of a PrCu alloy; wherein the mass percentage of the Cu to the PrCu is preferably 0.1-17%;

And/or, the content of B is 0.97-1.1%, and the percentage is the mass percentage of the total mass of the neodymium iron boron magnet material;

And/or, the Fe content is 65 to 79.5%, and the percentage is the mass percentage of the total mass of the neodymium iron boron magnet material.
The neodymium iron boron magnet material according to claim 7 or 8, characterized in that the neodymium iron boron magnet material comprises the following components by mass content: R: 29 to 32.6%; R includes R1 and R2, and R1 Including Nd and Dy, the content of Dy is less than 0.3% but not 0, the R1 is a rare earth element added during smelting, the content of R2 is 0.2-1%, the R2 includes Tb, and the R2 Rare earth element added during grain boundary diffusion; Co: 0.05-0.45%; M: 0.08-0.35%, the type of M includes one or more of Ti, Nb and Zr; Cu: 0.05-0.15%; B: 0.97～1.1%; Fe: 65～79.5%; the percentage is the mass percentage of the content of each component in the total mass of the raw material composition; the neodymium iron boron magnet material includes Nd 2 Fe l4 B crystal grains and its shell Layer, the two-grain boundary and the triangular area of the grain boundary adjacent to the Nd 2 Fe l4 B crystal grains; wherein the heavy rare earth elements in R1 are mainly distributed in the Nd 2 Fe l4 B crystal grains, and R2 is mainly distributed in the shell layer, The area of the two-grain boundary and the triangular area of the grain boundary, the area of the triangular area of the grain boundary is 1.96 to 2.99%; the continuity of the grain boundary of the neodymium iron boron magnet material is more than 97%; in the triangular area of the grain boundary The mass ratio of C and O is 0.41 to 0.49%; the mass ratio of C and O in the two-grain boundary is 0.3 to 0.4%; the two-grain boundary contains a new phase, and the new phase The chemical composition is: R x (Fe+Co) 100-xyz Cu y M z , x is 78.89～80.8, y is 0.55～0.66, z is 0.02～0.06; the new phase is in the two-grain boundary The ratio of the area in the middle to the total area of the two grain boundaries is 0.21 to 2.6%;

Alternatively, the neodymium iron boron magnet material includes the following components by mass content: R: 29-31%; R includes R1 and R2, said R1 includes Nd and Dy, and the amount of Dy is 0.1-0.2%, The R1 is a rare earth element added during smelting, the content of R2 is 0.2-0.8%, the R2 includes Tb, and the R2 is a rare earth element added during grain boundary diffusion; Co: 0.05-0.4%; M: 0.1% to 0.15%, the type of M includes one or more of Ti, Nb and Zr; Cu: 0.08% or less but not 0; B: 0.97 to 1.1%; Fe: 65 to 79.5%; the percentage is The content of each component accounts for the mass percentage of the total mass of the raw material composition; the neodymium iron boron magnet material includes Nd 2 Fe l4 B crystal grains and its shell layer, and two grains adjacent to the Nd 2 Fe l4 B crystal grains Boundary and grain boundary triangle area; wherein the heavy rare earth elements in R1 are mainly distributed in Nd 2 Fe 14 B crystal grains, and R2 is mainly distributed in the shell layer, the two-grain boundary and the grain boundary triangle area, the grain boundary triangle area The area ratio of the NdFeB magnet material is 1.96-2.8%; the grain boundary continuity of the neodymium iron boron magnet material is more than 98%; the mass ratio of C and O in the grain boundary triangle area is 0.41 to 0.48%; The mass ratio of C and O in the grain boundary is 0.34-0.4%; the two grain boundaries contain a new phase, and the chemical composition of the new phase is: R x (Fe+Co) 100-xyz Cu y M z , x is 78.89-80.8, y is 0.55-0.66, z is 0.02-0.06; the ratio of the area of the new phase in the two-grain boundary to the total area of the two-grain boundary is 0.34 ~2.55%.
An application of the neodymium iron boron magnet material according to any one of claims 6 to 9 in the preparation of magnetic steel; the magnetic steel is preferably 54SH, 54UH, 56SH high-performance magnetic steel.