JP7470804B2 - Neodymium iron boron magnet material, raw material composition, and manufacturing method - Google Patents

Description

The present invention specifically relates to neodymium iron boron magnet materials, raw material compositions, manufacturing methods, and applications.

Nd-Fe-B permanent magnet material is based on Nd ₂ Fe ₁₄ B compound and has advantages such as high magnetic properties, small thermal expansion coefficient, easy processing, and low cost, and since its introduction, it has been increasing at an average rate of 20-30% per year, becoming the most widely used permanent magnet material. According to the manufacturing method, Nd-Fe-B permanent magnets can be divided into three types: sintered, bonded, and hot pressed, of which sintered magnets account for more than 80% of the total production and are the most widely used.

With the continuous optimization of manufacturing processes and magnet components, the maximum energy product of sintered Nd-Fe-B magnets is already approaching the theoretical value. In recent years, with the rapid development of emerging industries such as wind power generation, hybrid vehicles, and inverter air conditioners, the demand for high-performance Nd-Fe-B magnets has increased, and at the same time, higher requirements are being placed on the performance of sintered Nd-Fe-B magnets, especially their coercive force, in these high-temperature applications.

In US Patent Application US5645651A, as is clear from Figure 1, the Curie temperature of Nd-Fe-B magnets increases with increasing Co content, and as is clear from a comparison of Sample 9 and Sample 2 in Table 1, when 20 at% Co is added to an Nd-Fe-B magnet, the coercive force can be improved without changing the residual magnetic flux density, compared to a device that does not add 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, and batteries, but Co is an important strategic resource and is expensive.

Chinese patent document CN110571007A discloses a rare earth permanent magnet material to which 1.5% or more of heavy rare earth elements and 0.8% or more of cobalt elements are simultaneously added, resulting in a Nd-Fe-B magnet with both excellent coercivity and magnetic properties.

For these reasons, in the conventional technology, neodymium iron boron magnet materials with excellent magnetic properties (residual magnetic flux density, retentivity, and thermal stability) require the addition of large amounts of heavy rare earth elements and cobalt elements, which increases the cost. There is a need to develop a technical solution that can still achieve the same or higher level, provided that small amounts of heavy rare earth elements or cobalt elements are added.

The present invention aims to provide a neodymium iron boron magnet material, a raw material composition, a manufacturing method, and applications to resolve the drawback of the high cost of the neodymium iron boron magnet material, which requires the addition of large amounts of heavy rare earth elements and cobalt elements to improve the magnetic properties (residual magnetic flux density, coercive force, and thermal stability) of the neodymium iron boron magnet material of the prior art. The neodymium iron boron magnet material of the present invention has high residual magnetic flux density and coercive force, and is excellent in thermal stability.

The present invention uses the following technical ideas to solve the above technical problems.

The present invention provides a raw material composition of neodymium iron boron magnet material, which comprises the following components in the following mass contents:
R: 28 to 33%, R is a rare earth element, R includes R1 and R2, R1 is a rare earth element added during melting and refining, 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% to 1%;
Co: <0.5%, but not 0;
M: ≦0.4%, but not 0, and 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 to 1.1%,
Fe: 60 to 70%,
The percentages refer to the mass percentage of each component based on 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%, for example, 29.58%, 29.75%, 29.8%, 30.65%, 30.7%, 30.9%, 30.95%, 31.35% or 32.6%, more preferably 29 to 31%, and the percentage is the mass percentage based on the total mass of the raw material composition.

In the present invention, the content of Nd in R1 of the raw material composition may be that which is conventional in the field, and is preferably 28 to 32.5%, for example, 28.6%, 29.9%, 30.4% or 32.1%, where the percentage is the mass percentage relative to the total mass of the raw material composition.

In the present invention, the content of Dy in R1 is preferably 0.3% or less, but not 0, and is, for example, 0.05%, 0.08%, 0.1%, 0.15% or 0.2%, more preferably 0.1 to 0.2%, and the percentage is the mass percentage relative to the total mass of the raw material composition.

In the present invention, R1 may further include other common rare earth elements in this field, for example, one or more of Pr, Ho, Tb, Gd, and Y.

Here, when R1 contains Pr, the Pr may be added in a form common in this field, 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 a combination of "a mixture of PrNd, pure Pr, and pure Nd". When added in the form of PrNd, the Pr:Nd ratio is preferably 25:75 or 20:80. When added in the form of a mixture of pure Pr and pure Nd, or in the form of a combination of "a mixture of PrNd, pure Pr, and pure Nd", the Pr content is preferably 0.1 to 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. In the present invention, the pure Pr or pure Nd generally refers to a purity of 99.5% or more.

When R1 contains Ho, the content of Ho is preferably 0.1 to 0.2%, and the percentage is the mass percentage of the total mass of the neodymium iron boron magnet material.

When R1 contains Gd, the Gd content is preferably 0.1 to 0.2%, and the percentage is the mass percentage of the total mass of the neodymium iron boron magnet material.

When R1 contains Y, the content of Y is preferably 0.1 to 0.2%, and the percentage is the mass percentage based on the total mass of the raw material composition.

In the present invention, the content of R2 is preferably 0.2 to 0.9%, for example, 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 relative to the total mass of the raw material composition.

In the present invention, the content of Tb in R2 is preferably 0.2% to 0.9%, for example, 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 relative to the total mass of the raw material composition.

In the present invention, it is preferable that R2 further contains one or more of Pr, Dy, Ho, and Gd.

When R2 contains Pr, the Pr content is preferably 0.2% or less, but not 0, e.g., 0.1%, and the percentage is the mass percentage relative to the total mass of the raw material composition.

When R2 contains Dy, the content of Dy is preferably 0.3% or less, but not 0, e.g., 0.1%, and the percentage is the mass percentage relative to the total mass of the raw material composition.

When R2 contains Ho, the content of Ho is preferably 0.2% or less, but not 0, e.g., 0.1%, and the percentage is the mass percentage relative to the total mass of the raw material composition.

When R2 contains Gd, the content of Gd is 0.2% or less, but not 0, e.g., 0.1%, and the percentage is the mass percentage of the total mass of the raw material composition,

In the present invention, the Co content is preferably 0.45% or less, but not 0, and is, for example, 0.05%, 0.1%, 0.2%, 0.3%, 0.4% or 0.45%, more preferably 0.05 to 0.4%, and the percentage is the mass percentage relative to the total mass of the raw material composition.

In the present invention, the content of M is preferably 0.08 to 0.35%, more preferably 0.1 to 0.15%, for example, 0.08%, 0.1%, 0.16%, 0.2%, 0.25%, 0.3% or 0.35%, and the percentage is the mass percentage based on 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.

When the M contains Ti, the Ti content is preferably 0.05 to 0.3%, for example, 0.05%, 0.1%, or 0.3%, and the percentage is the mass percentage relative to the total mass of the raw material composition,

When M contains Zr, the content of Zr is preferably 0.08 to 0.35%, for example, 0.08%, 0.2%, or 0.35%, and the percentage is the mass percentage based on the total mass of the raw material composition,

When the M contains Nb, the content of Nb is preferably 0.05 to 0.3%, for example, 0.05%, 0.2%, or 0.3%, and the percentage is the mass percentage based on the total mass of the raw material composition,

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

When M contains Ga, the Ga content is preferably 0.2% or more, or 0.01% or less, but not 0, and the percentage is the mass percentage based on 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, it is preferable that the raw material composition further contains Al.

Here, the Al content is preferably 0.2% or less, but not 0, and is more preferably 0.03 to 0.2%, for example 0.1%, and the percentage is the mass percentage relative to the total mass of the raw material composition.

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

In the present invention, the Cu content is preferably 0.05 to 0.15%, for example, 0.05%, 0.06%, 0.07%, 0.08%, 0.1% or 0.15%, or the Cu content is preferably 0.08% or less, but not 0, for example, 0.05%, 0.06% or 0.07%, and the percentage is the mass percentage based on the total mass of the raw material composition.

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

In the present invention, the content of B is preferably 0.97 to 1.1%, for example, 0.99% or 1%, and the percentage is the mass percentage based on the total mass of the raw material composition.

In the present invention, the Fe content 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%, where the percentage is the mass percentage relative to the total mass of the raw material composition.

In the present invention, the raw material composition preferably contains the following components:
R: 29-32.6%, R includes R1 and R2, R1 includes Nd and Dy, the amount of Dy used is 0.3% or less but not 0, R1 is a rare earth element added during melting and refining, and 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 to 0.45%,
M: 0.08 to 0.35%, wherein M contains one or more of Ti, Nb and Zr;
Cu: 0.05 to 0.15%,
B: 0.97 to 1.1%,
Fe: 65 to 79.5%,
The percentages refer to the mass percentage of each component based on the total mass of the raw material composition.

In the present invention, the raw material composition preferably contains the following components:
R: 29-31%, R includes R1 and R2, R1 includes Nd and Dy, the amount of Dy used is 0.1-0.2%, R1 is a rare earth element added during melting and smelting, the content of R2 is 0.2-0.8%, R2 includes Tb, and R2 is a rare earth element added during grain boundary diffusion,
Co: 0.05 to 0.4%,
M: 0.1 to 0.15%, wherein M contains 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 percentages refer to the mass percentage of each component based on the total mass of the raw material composition.

In one preferred embodiment of the present invention, the raw material composition of the NdFeB magnet material comprises the following components in the following mass contents:
R1 contains 28.6% Nd, 0.05% Dy, and 0.1% Pr, and R1 is a rare earth element added during melting and smelting. R2 contains 1% Tb, and R2 is a rare earth element added during grain boundary diffusion. Co is 0.05%, Ti is 0.05%, Nb is 0.2%, Cu is 0.05%, B is 0.99%, and Fe is 68.91%.
The percentages refer to the mass percentage of each component based on the total mass of the raw material composition.

In one preferred embodiment of the present invention, the raw material composition of the NdFeB magnet material comprises the following components in the following mass contents:
R1 contains 28.6% Nd, 0.1% Dy, and 0.2% Pr, and R1 is a rare earth element added during melting and smelting. R2 contains 0.9% Tb, and R2 is a rare earth element added during grain boundary diffusion. Co is 0.05%, Ti is 0.1%, Cu is 0.05%, B is 1%, and Fe is 69%.
The percentages refer to the mass percentage of each component based on the total mass of the raw material composition.

In one preferred embodiment of the present invention, the raw material composition of the NdFeB magnet material comprises the following components in the following mass contents:
R1 contains 28.6% Nd and 0.08% Dy, and R1 is a rare earth element added during melting and smelting. R2 contains 0.9% Tb and R2 is a rare earth element added during grain boundary diffusion. Co is 0.1%, Ti is 0.3%, Nb is 0.05%, Ga is 0.05%, Cu is 0.06%, B is 1.1%, and Fe is 68.76%.
The percentages refer to the mass percentage of each component based on the total mass of the raw material composition.

In one preferred embodiment of the present invention, the raw material composition of the NdFeB magnet material comprises the following components in the following mass contents:
R1 contains 29.9% Nd and 0.1% Dy, and R1 is a rare earth element added during melting and smelting. R2 contains 0.8% Tb and 0.1% Pr, and R2 is a rare earth element added during grain boundary diffusion. Co is 0.1%, Zr is 0.2%, Al is 0.2%, Cu is 0.03%, Cu is 0.05%, B is 0.99%, and Fe is 67.53%.
The percentages refer to the mass percentage of each component based on the total mass of the raw material composition.

In one preferred embodiment of the present invention, the raw material composition of the NdFeB magnet material comprises the following components in the following mass contents:
R1 contains 30.4% Nd and 0.05% Dy, and R1 is a rare earth element added during melting and smelting. R2 contains 0.8% Tb and 0.1% Dy, and R2 is a rare earth element added during grain boundary diffusion. Co is 0.2%, Zr is 0.08%, Cu is 0.1%, B is 0.99%, and Fe is 67.28%.
The percentages refer to the mass percentage of each component based on the total mass of the raw material composition.

In one preferred embodiment of the present invention, the raw material composition of the NdFeB magnet material comprises the following components in the following mass contents:
R1 contains 29.9% Nd and 0.15% Dy, and R1 is a rare earth element added during melting and smelting. R2 contains 0.6% Tb, and R2 is a rare earth element added during grain boundary diffusion. Co is 0.2%, Zr is 0.35%, Cu is 0.1%, B is 1%, and Fe is 67.7%.
The percentages refer to the mass percentage of each component based on the total mass of the raw material composition.

In one preferred embodiment of the present invention, the raw material composition of the NdFeB magnet material comprises the following components in the following mass contents:
R1 contains 29.9% Nd and 0.2% Dy, and R1 is a rare earth element added during melting and smelting. R2 contains 0.6% Tb, and R2 is a rare earth element added during grain boundary diffusion. Co is 0.3%, Nb is 0.05%, Ga is 0.01%, Al is 0.1%, Cu is 0.07%, B is 1.1%, and Fe is 67.67%.
The percentages refer to the mass percentage of each component based on the total mass of the raw material composition.

In one preferred embodiment of the present invention, the raw material composition of the NdFeB magnet material comprises the following components in the following mass contents:
R1 contains 30.4% Nd and 0.05% Dy, and R1 is a rare earth element added during melting and smelting. R2 contains 0.3% Tb and 0.2% Pr, and R2 is a rare earth element added during grain boundary diffusion. Co is 0.34%, Nb is 0.2%, Cu is 0.12%, Cu is 0.03%, B is 0.99%, and Fe is 67.31%.
The percentages refer to the mass percentage of each component based on the total mass of the raw material composition.

In one preferred embodiment of the present invention, the raw material composition of the NdFeB magnet material comprises the following components in the following mass contents:
R1 contains 32.1% Nd and 0.3% Dy, and R1 is a rare earth element added during melting and smelting. R2 contains 0.2% Tb, and R2 is a rare earth element added during grain boundary diffusion. Co is 0.45%, Nb is 0.3%, Cu is 0.15%, B is 1.1%, and Fe is 65.4%.
The percentages refer to the mass percentage of each component based on the total mass of the raw material composition.

In one preferred embodiment of the present invention, the raw material composition of the NdFeB magnet material comprises the following components in the following mass contents:
R1 contains 29.9% Nd and 0.2% Dy, and R1 is a rare earth element added during melting and smelting. R2 contains 0.6% Tb and R2 is a rare earth element added during grain boundary diffusion. Co is 0.3%, Nb is 0.05%, Ga is 0.01%, Al is 0.03%, Cu is 0.07%, B is 1.1%, and Fe is 67.74%.
The percentages refer to the mass percentage of each component based on the total mass of the raw material composition.

The present invention further provides a method for producing a neodymium iron boron magnet material using the above-mentioned raw material composition, which is a typical diffusion production method in this field, in which the R1 element is added in the melting and smelting process and the R2 element is added in the grain boundary diffusion process.

In the present invention, the manufacturing method preferably includes the following steps:

The elements other than R2 in the raw material composition of the neodymium iron boron magnet material described above are melted and refined, milled, molded, and sintered to obtain a sintered body, and then a mixture of the sintered body and R2 is diffused into the grain boundaries.

The melting and smelting operations and conditions may be those of the conventional melting and smelting processes in this field, and generally, the elements other than R2 in the raw material composition of the neodymium-iron-boron magnet material are melted, smelted and cast through an ingot process and a strip casting process to obtain alloy pieces.

As those skilled in the art will appreciate, since rare earth elements are usually lost during the melting, smelting and sintering processes, in order to ensure the quality of the final product, an extra rare earth element (usually Nd element) is generally added to the raw material composition components during the melting and smelting process in an amount of 0-0.3 wt%, and the percentage refers to the mass percentage of the content of the extra rare earth element relative to the total content of the raw material composition. Also, the content of the extra rare earth element is not included in the range of the raw material composition.

The temperature of the melting and smelting process can be 1300 to 1700°C, and is preferably 1450 to 1550°C.

The melting and smelting environment can be a vacuum of 0.05 Pa.

The melting and smelting equipment is typically a medium frequency vacuum melting furnace, such as a medium frequency vacuum induction rapid solidification melt spinning furnace.

Here, the milling operation and conditions can be conventional milling processes in this field, and generally include hydrogrinding milling and/or jet milling.

The hydrogen crushing milling 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 to 650°C, preferably 500 to 550°C. The pressure of the hydrogen absorption is generally 50 to 600 kPa, preferably 300 to 500 kPa.

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

Here, the molding operation and conditions can be those of a typical molding process in this field. For example, a molding method in a magnetic field. The magnetic field strength of the molding method in a magnetic field is generally 1.5 T or more.

Here, the sintering operation and conditions can be those of a typical sintering process in this field.

The sintering can be carried out under vacuum conditions of less than 0.5 Pa.

The sintering temperature can be 1000 to 1200°C.

The sintering time can be 0.5 to 10 hours, preferably 2 to 5 hours.

As will be appreciated by those skilled in the art, the present invention generally further includes a coating operation of R2 prior to the grain boundary diffusion.

Here, R2 is generally coated in the form of a fluoride or a low melting point alloy, for example, a fluoride of Tb. When Dy is further included, it is preferable that Dy is coated in the form of a fluoride of Dy.

Here, when R2 contains Pr, it is preferable that the Pr is added in the form of a PrCu alloy.

When the R2 contains Pr and the Pr is involved in grain boundary diffusion in the form of a PrCu alloy, the mass ratio of the Cu to the PrCu alloy in the PrCu alloy is preferably 0.1 to 17%. The timing of adding the Cu in the manufacturing method is preferably the grain boundary diffusion process, or it is added simultaneously to the melting and smelting process and the grain boundary diffusion process.

In the present invention, the operation and conditions of the grain boundary diffusion treatment can be those of a typical grain boundary diffusion process in this field.

The temperature of the grain boundary diffusion treatment can be 800 to 1000°C, for example 850°C.

The duration of the grain boundary diffusion treatment can be 5 to 20 hours, and is preferably 5 to 15 hours.

After the grain boundary diffusion, a low-temperature tempering treatment is further performed according to the conventional method in this field. The temperature of the low-temperature tempering treatment can be generally 460 to 560°C. The time of the low-temperature tempering can be generally 1 to 3 hours.

The present invention further provides a neodymium iron boron magnet material produced by the above-mentioned production method.

The present invention further provides a neodymium iron boron magnet material, comprising the following components in the following mass content:
R: 28-33%, R includes R1 and R2, R1 includes Nd and Dy, R2 includes Tb, and the content of R2 is 0.2-1 wt%;
Co: <0.5%, but not 0;
M: ≦0.4%, but not 0, and 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 to 1.5%,
Fe: 60 to 70%,
The percentages are the mass percentages of each component relative to the total mass of the neodymium iron boron magnet material;
The neodymium iron boron magnet material includes Nd ₂ Fe ₁₄ B crystal grains and their shell layers, two-particle grain boundaries and grain boundary triangular regions adjacent to the Nd ₂ Fe ₁₄ B crystal grains, in which the heavy rare earth elements in R1 are mainly distributed in the Nd ₂ Fe ₁₄ B crystal grains, and R2 are mainly distributed in the shell layers, two-particle grain boundaries and grain boundary triangular regions, the area ratio of the grain boundary triangular regions is 1.8-2.99%, the grain boundary continuity of the two-particle grain boundaries is 96% or more, the mass ratio of C and O in the grain boundary triangular regions is 0.4-0.5%, and the mass ratio of C and O in the two-particle grain boundaries is 0.3-0.5%.

In the present invention, "heavy rare earth elements in R1 are mainly distributed in _{Nd2Fe14B crystal} grains" can be understood to mean that the heavy rare earth elements in R1 by the conventional melting, smelting and sintering process in this field are mainly distributed in _Nd2Fe14B crystal grains (generally _95wt % or more), with a small amount distributed in grain boundaries. "R2 is mainly distributed in the shell layer" can be understood to mean that R2 by the conventional grain boundary diffusion process in this field is mainly distributed in the shell layer, two grain boundaries and grain boundary triangular regions of _{Nd2Fe14B crystal} grains (generally _95wt % or more), with a small amount also diffusing to the outer edges of _Nd2Fe14B crystal grains, for example, _{Nd2Fe14B crystal} grains.

In the present invention, the method for calculating the grain boundary continuity is the ratio of the length occupied by phases other than voids at the grain boundary (phases are, for example, B-rich phase, rare earth rich phase, rare earth oxide, rare earth carbide, etc.) to the total length of the grain boundary. When the grain boundary continuity exceeds 96%, it is called a continuous channel.

In the present invention, the grain boundary triangular region generally refers to a location where three or more grain boundaries intersect, and contains a B-rich phase, a rare earth rich phase, rare earth oxides, rare earth carbides, and cavities. The area ratio of the grain boundary triangular region is calculated as the ratio of the area of the grain boundary triangular region to the total area of the "crystal grains and grain boundaries."

Among them, rare earth oxides and rare earth carbides are mainly produced by introducing C and O elements during the preparation process. Because the rare earth content of the grain boundaries is high, C and O are usually distributed more at the grain boundaries in the magnet material, and therefore exist in the form of rare earth carbides and rare earth oxides, respectively. The C and O elements are introduced by the usual method in this field, and are generally introduced as impurities or atmosphere. Specifically, for example, additives are introduced in the jet mill and press process, and these additives are removed by heating during sintering, but a small amount of C and O elements inevitably remain, and for example, a small amount of O element is inevitably introduced by the atmosphere in the preparation process. In the present invention, the C and O contents in the final neodymium iron boron magnet material product obtained by inspection and measurement are 1000 and 1200 ppm or less, respectively, which are within the range of impurities normally accepted in this field, and are not included in the product element statistics table.

In the present invention, the area ratio of the grain boundary triangular region is preferably 1.96 to 2.99%, for example, 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%, and more preferably 98% or more.

In the present invention, the mass ratio of C and O in the grain boundary triangular 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%, where the percentage is the ratio of the mass of C and O in the grain boundary triangular region to the total mass of all elements in the grain boundary.

In the present invention, the mass ratio of C and O at the two-particle grain boundary is preferably 0.3 to 0.4%, for example, 0.3%, 0.34%, 0.35%, 0.36%, 0.37%, 0.38% or 0.4%, more preferably 0.34 to 0.4%, where the percentage is the ratio of the mass of C and O at the two-particle grain boundary to the total mass of all elements at the grain boundary.

In the present invention, as will be understood by those skilled in the art, C and O elements are usually present in the grain boundary phase in the form of rare earth carbides and rare earth oxides, so the "mass ratio of C and O in the grain boundary triangular region" and the "mass ratio of C and O in the two-particle grain boundary" correspond to the rare earth carbides and rare earth oxides of the impurity phase, respectively. In addition, based on the fact that the comparative example is smaller than the value obtained by subtracting the "mass ratio of C and O (%) in the two-particle grain boundary" from the "mass ratio of C and O in the grain boundary triangular region" in the example, it can be concluded that the impurity phase migrates from the grain boundary triangular region to the two-particle grain boundary, which explains the reason for the improvement of grain boundary continuity from a mechanism perspective.

In the present invention, in addition to the two impurity phases of rare earth oxide and rare earth carbide, preferably, a new phase is further detected at the two grain boundary of the neodymium iron boron magnet material, and the chemical composition of the new phase is R _x (Fe + Co) _100-x-y-z Cu _y M _z , where R in R _x (Fe + Co) _100-x-y-z Cu _y M _z includes one or more of Nd, Dy and Tb, M is 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, and z is 0.1 but not 0.

In the formula 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 composition 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) _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) _{19.64Cu0.58M0.02} , _{R79.71 ( Fe} + _{Co ) 19.65Cu0.62M0.02 , R80.18} (Fe+ _{Co ) 19.16Cu0.62M0.04} , _R79.4 (Fe+Co) _{19.94Cu0.64M0.02 .}

In the present invention, the ratio of the area of the two-particle boundary of the new phase having the chemical composition R _x (Fe+Co) _100-x-y-z Cu _y M _z to the total area of the two-particle boundary is preferably 0.2 to 2.6%, for example, 0.21%, 0.34%, 0.85%, 1.08%, 1.15%, 1.21%, 1.33%, 1.87%, 2.34% or 2.55%, and more preferably 0.34 to 2.55%.

The inventors speculate that the new phase is generated at the grain boundary between two particles, thereby further improving grain boundary continuity and 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%, for example, 29.58%, 29.75%, 29.8%, 30.65%, 30.7%, 30.9%, 30.95%, 31.35% or 32.6%, more preferably 29 to 31%, where the percentage is the mass percentage of the total mass of the neodymium iron boron magnet material.

In the present invention, the Nd content in R1 of the neodymium iron boron magnet material can be the usual content in this field, preferably 28-32.5%, for example, 28.6%, 29.9%, 30.4% or 32.1%, where the percentage is the mass percentage of the total mass of the neodymium iron boron magnet material.

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

In the present invention, R1 may further include other common rare earth elements in this field, such as one or more of Pr, Ho, Tb, Gd, and Y.

Here, when R1 contains Pr, the Pr may be added in a form that is common in this field, for example, in the form of PrNd, or in the form of a mixture of pure Pr and pure Nd, or in a combination of "a mixture of PrNd, pure Pr, and pure Nd". When added in the form of PrNd, the Pr:Nd ratio is preferably 25:75 or 20:80. When added in the form of a mixture of pure Pr and pure Nd, or in the form of a combination of "a mixture of PrNd, pure Pr, and pure Nd", the Pr content is preferably 0.1 to 2%, 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, the pure Pr or pure Nd generally refers to a purity of 99.5% or more.

Here, when R1 contains Ho, the content of Ho is preferably 0.1 to 0.2%, and the percentage is the mass percentage of the total mass of the neodymium iron boron magnet material.

Here, when R1 contains Gd, the Gd content is preferably 0.1 to 0.2%, and the percentage is the mass percentage of the total mass of the neodymium iron boron magnet material.

Here, when R1 contains Y, the content of Y is preferably 0.1 to 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%, for example, 0.2%, 0.3%, 0.5%, 0.6% or 0.8%, more preferably 0.2 to 0.8%, where the percentage is the mass percentage of the total mass of the neodymium iron boron magnet material.

In the present invention, the content of Tb in R2 is preferably 0.2 to 0.9%, for example, 0.2%, 0.3%, 0.5%, 0.6%, 0.8% or 0.9%, more preferably 0.2 to 0.8%, where the percentage is the mass percentage of the total mass of the neodymium iron boron magnet material.

In the present invention, it is preferable that R2 further contains one or more of Pr, Dy, Ho, and Gd.

Here, when R2 contains Pr, the Pr content 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.

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

Here, when R2 contains 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.

Here, when R2 contains Gd, the content of Gd 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.

In the present invention, the Co content is preferably 0.45% or less, but not 0, and is, for example, 0.05%, 0.1%, 0.2%, 0.3% or 0.4%, more preferably 0.05 to 0.4%, where 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 to 0.35%, for example, 0.08%, 0.1%, 0.16%, 0.2%, 0.25%, 0.3% or 0.35%, and more preferably 0.1 to 0.15%, where the percentage is the mass percentage of the total mass of the neodymium iron boron magnet material.

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.

Here, when M contains Ti, the Ti content is preferably 0.05 to 0.3%, for example 0.1%, and the percentage is the mass percentage of the total mass of the neodymium iron boron magnet material.

Here, when M contains Zr, the content of Zr is preferably 0.08 to 0.35%, for example 0.2%, and the percentage is the mass percentage of the total mass of the neodymium iron boron magnet material.

Here, when M contains Nb, the Nb content is preferably 0.05 to 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, it is preferable that the M in the neodymium iron boron magnet material further includes one or more of Bi, Sn, Zn, Ga, In, Au, and Pb.

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

Here, when the M contains Ga and Ga≧0.2%, preferably, in the composition of the M element, Ti+Nb≦0.07%, and the percentage is the mass percentage of the total mass of the neodymium iron boron magnet material,

In the present invention, it is preferable that the neodymium iron boron magnet material further contains Al.

Here, the content of Al is preferably 0.2% or less, but not 0, for example, 0.03 to 0.2%, for example, 0.1%, and the percentage is the mass percentage of the total mass of the neodymium iron boron magnet material.

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

In the present invention, the Cu content is preferably 0.05-0.15%, for example, 0.05%, 0.07%, 0.08%, 0.1% or 0.15%, or the Cu content is preferably 0.08% or less, but not 0, for example, 0.05%, 0.07% or 0.08%, where 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 melting and smelting and/or adding during grain boundary diffusion. When the Cu is added during grain boundary diffusion, the content of Cu added during grain boundary diffusion is preferably 0.03 to 0.15%, for example 0.05%, where the percentage is the mass percentage of the total mass of the neodymium iron boron magnet material. When the Cu is added during grain boundary diffusion, the Cu is preferably added in the form of a PrCu alloy, where the mass percentage of the Cu in the PrCu is preferably 0.1 to 17%.

In the present invention, the B content is preferably 0.97 to 1.1%, for example, 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 Fe content 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%, where 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 contains the following components in the following mass contents:
R: 29-32.6%, R includes R1 and R2, R1 includes Nd and Dy, the amount of Dy used is 0.3% or less but not 0, R1 is a rare earth element added during melting and smelting, the content of R2 is 0.2-1%, R2 includes Tb, and R2 is a rare earth element added during grain boundary diffusion,
Co: 0.05 to 0.45%,
M: 0.08 to 0.35%, the type of M including one or more of Ti, Nb and Zr;
Cu: 0.05 to 0.15%,
B: 0.97 to 1.1%,
Fe: 65 to 79.5%,
The percentages are the mass percentages of the content of each component relative to the total mass of the neodymium iron boron magnet material,
The neodymium iron boron magnet material includes Nd ₂ Fe ₁₄ B crystal grains and their shell layers, two-grain grain boundaries and grain boundary triangular regions adjacent to the Nd ₂ Fe ₁₄ 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 are mainly distributed in the shell layers, two-grain grain boundaries and grain boundary triangular regions, the area ratio of the grain boundary triangular regions is 1.96-2.99%, the grain boundary continuity of the two-grain grain boundaries is 97% or more, the mass ratio of C and O in the grain boundary triangular regions is 0.41-0.49%, and the mass ratio of C and O in the two-grain grain boundaries is 0.3-0.4%, and the two-grain grain boundaries further include a new phase, and the chemical composition of the new phase is R _x (Fe+Co) _100-x-y-z Cu _y M _z , x is 78.89 to 80.8, y is 0.55 to 0.66, z is 0.02 to 0.06, and the ratio of the area of the new phase at the two-grain boundary to the total area of the two-grain boundary is 0.21 to 2.6%.

In the present invention, the neodymium iron boron magnet material preferably contains the following components in the following mass contents:
R: 29-31%, R includes R1 and R2, R1 includes Nd and Dy, the amount of Dy used is 0.1-0.2%, R1 is a rare earth element added during melting and smelting, the content of R2 is 0.2-0.8%, R2 includes Tb, and R2 is a rare earth element added during grain boundary diffusion,
Co: 0.05 to 0.4%,
M: 0.1 to 0.15%, the type of M including 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 percentages are the mass percentages of the content of each component relative to the total mass of the neodymium iron boron magnet material,
The neodymium iron boron magnet material includes Nd ₂ Fe ₁₄ B crystal grains and their shell layers, two-grain grain boundaries and grain boundary triangular regions adjacent to the Nd ₂ Fe ₁₄ 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 are mainly distributed in the shell layers, two-grain grain boundaries and grain boundary triangular regions, the area ratio of the grain boundary triangular regions is 1.96-2.8%, the grain boundary continuity of the two-grain grain boundaries is 98% or more, the mass ratio of C and O in the grain boundary triangular regions is 0.41-0.48%, and the mass ratio of C and O in the two-grain grain boundaries is 0.34-0.4%, and the two-grain grain boundaries further include a new phase, and the chemical composition of the new phase is R _x (Fe+Co) _100-x-y-z Cu _y M _z , x is 78.89 to 80.8, y is 0.55 to 0.66, z is 0.02 to 0.06, and the ratio of the area of the new phase at the two-grain boundary to the total area of the two-grain boundary is 0.34 to 2.55%.

In one preferred embodiment of the present invention, the NdFeB magnet material comprises the following components in mass content:
R1: Nd is 28.6%, Dy is 0.05%, and Pr is 0.1%, and the R1 is a rare earth element added during melting and smelting; R2: Tb is 1%, and the R2 is a rare earth element added during grain boundary diffusion;
Co: 0.05%,
Ti: 0.05%,
Nb: 0.2%,
Cu: 0.05%,
B: 0.99%,
Fe: 68.91%,
The percentages are the mass percentages of the content of each component relative to the total mass of the neodymium iron boron magnet material,
The neodymium iron boron magnet material includes Nd ₂ Fe ₁₄ B crystal grains and their shell layers, two-grain grain boundaries and grain boundary triangular regions adjacent to the Nd ₂ Fe ₁₄ 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 are mainly distributed in the shell layers, two-grain grain boundaries and grain boundary triangular regions, the area ratio of the grain boundary triangular regions is 1.98%, the grain boundary continuity of the two-grain grain boundaries is 98.13%, the mass ratio of C and O in the grain boundary triangular regions is 0.47%, the mass ratio of C and O in the two-grain grain boundaries is 0.35%, and the two-grain grain boundaries further include a new phase, and its chemical composition is R _79.43 (Fe+Co) _19.92 Cu _0.63 M. _0.02 , R is one or more of Nd, Dy, Pr and Tb, M is Ti and Nb, and the ratio of the area of the new phase at the two-grain boundary to the total area of the two-grain boundary is 1.87%.

In one preferred embodiment of the present invention, the NdFeB magnet material comprises the following components in mass content:
R1: Nd is 28.6%, Dy is 0.1%, and Pr is 0.2%, and the R1 is a rare earth element added during melting and smelting; R2: Tb is 0.9%, and the R2 is a rare earth element added during grain boundary diffusion;
Co: 0.05%,
Ti: 0.1%,
Cu: 0.05%,
B: 1%,
Fe: 69%,
The percentages are the mass percentages of the content of each component relative to the total mass of the neodymium iron boron magnet material,
The neodymium iron boron magnet material includes Nd ₂ Fe ₁₄ B crystal grains and their shell layers, two-grain grain boundaries and grain boundary triangular regions adjacent to the Nd ₂ Fe ₁₄ 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 are mainly distributed in the shell layers, two-grain grain boundaries and grain boundary triangular regions, the area ratio of the grain boundary triangular regions is 2.05%, the grain boundary continuity of the two-grain grain boundaries is 97.92%, the mass ratio of C and O in the grain boundary triangular regions is 0.48%, the mass ratio of C and O in the two-grain grain boundaries is 0.3%, and the two-grain grain boundaries further include a new phase, and its chemical composition is R _78.89 (Fe + Co) _20.4 9Cu _0.58 M _0.04 , R is one or more of Nd, Dy, Pr and Tb, M is Ti, and the ratio of the area of the new phase at the two-grain boundary to the total area of the two-grain boundary is 2.34%.

In one preferred embodiment of the present invention, the NdFeB magnet material comprises the following components in mass content:
R1: Nd is 28.6% and Dy is 0.08%, R1 is a rare earth element added during melting and smelting, R2: Tb is 0.9%, R2 is a 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%,
Fe: 68.76%,
The percentages are the mass percentages of the content of each component relative to the total mass of the neodymium iron boron magnet material,
The neodymium iron boron magnet material includes Nd ₂ Fe ₁₄ B crystal grains and their shell layers, two-grain grain boundaries and grain boundary triangular regions adjacent to the Nd ₂ Fe ₁₄ 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 are mainly distributed in the shell layers, two-grain grain boundaries and grain boundary triangular regions, the area ratio of the grain boundary triangular regions is 1.96%, the grain boundary continuity of the two-grain grain boundaries is 97.85%, the mass ratio of C and O in the grain boundary triangular regions is 0.41%, the mass ratio of C and O in the two-grain grain boundaries is 0.36%, and the two-grain grain boundaries further include a new phase, and 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 is one or more of Ti, Nb and Ga, and the ratio of the area of the new phase at the two-grain grain boundary to the total area of the two-grain grain boundary is 1.15%.

In one preferred embodiment of the present invention, the NdFeB magnet material comprises the following components in mass content:
R1: Nd is 29.9% and Dy is 0.1%, and R1 is a rare earth element added during melting and refining.
R2: Tb is 0.8% and Pr is 0.1%, and R2 is a rare earth element added during grain boundary diffusion;
Co: 0.1%
Zr: 0.2%,
Al: 0.2%,
Cu added during melting and refining: 0.03%
Cu added during grain boundary diffusion: 0.05%
B: 0.99%,
Fe: 67.53%,
The percentages are the mass percentages of the content of each component relative to the total mass of the neodymium iron boron magnet material,
The neodymium iron boron magnet material includes _{Nd2Fe14B crystal} grains and their shell layers, two-grain grain boundaries and grain boundary triangular regions adjacent to the _Nd2Fe14B crystal grains, wherein the heavy rare earth elements in R1 are mainly distributed in _{the Nd2Fe14B crystal} grains, and R2 are mainly distributed in the shell layers, two-grain grain boundaries and grain boundary triangular regions, the area ratio of the grain boundary triangular regions is 1.96%, the grain boundary continuity of the two-grain grain boundaries is 97.85%, the mass ratio of C and O in the grain boundary triangular regions is 0.46%, the mass ratio of C and O in the two-grain grain boundaries is 0.36%, and the two-grain grain boundaries further include a new phase, and its chemical composition is _R79.21 (Fe+ _Co ) _{20.11Cu0.66M 0.02} , R is one or more of Nd, Dy, Pr and Tb, M is Zr, and the ratio of the area of the new phase at the two-grain boundary to the total area of the two-grain boundary is 2.25%.

In one preferred embodiment of the present invention, the NdFeB magnet material comprises the following components in mass content:
R1: Nd is 30.4% and Dy is 0.05%, and R1 is a rare earth element added during melting and refining.
R2: Tb is 0.8% and Dy is 0.1%, and R2 is a rare earth element added during grain boundary diffusion;
Co: 0.2%,
Zr: 0.08%,
Cu: 0.1%,
B: 0.99%,
Fe: 67.28%,
The percentages are the mass percentages of the content of each component relative to the total mass of the neodymium iron boron magnet material,
The neodymium iron boron magnet material includes Nd ₂ Fe ₁₄ B crystal grains and their shell layers, two-grain grain boundaries and grain boundary triangular regions adjacent to the Nd ₂ Fe ₁₄ B crystal grains, in which the heavy rare earth elements in R1 are distributed in the Nd ₂ Fe ₁₄ B crystal grains, and R2 is mainly distributed in the shell layers, two-grain grain boundaries and grain boundary triangular regions, the area ratio of the grain boundary triangular regions is 2.78%, the grain boundary continuity of the two-grain grain boundaries is 98.54%, the mass ratio of C and O in the grain boundary triangular regions is 0.48%, the mass ratio of C and O in the two-grain grain boundaries is 0.34%, and the two-grain grain boundaries further include a new phase, and 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, M is Zr, and the ratio of the area of the new phase at the two-grain boundary to the total area of the two-grain boundary is 0.85%.

In one preferred embodiment of the present invention, the NdFeB magnet material comprises the following components in mass content:
R1: Nd is 29.9% and Dy is 0.15%, and R1 is a rare earth element added during melting and refining.
R2: Tb is 0.6%, and R2 is a rare earth element added during grain boundary diffusion;
Co: 0.2%,
Zr: 0.35%,
Cu: 0.1%,
B: 1%,
Fe: 67.7%,
The percentages are the mass percentages of the content of each component relative to the total mass of the neodymium iron boron magnet material,
The neodymium iron boron magnet material includes Nd ₂ Fe ₁₄ B crystal grains and their shell layers, two-grain grain boundaries and grain boundary triangular regions adjacent to the Nd ₂ Fe ₁₄ 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 are mainly distributed in the shell layers, two-grain grain boundaries and grain boundary triangular regions, the area ratio of the grain boundary triangular regions is 2.73%, the grain boundary continuity of the two-grain grain boundaries is 98.01%, the mass ratio of C and O in the grain boundary triangular regions is 0.41%, the mass ratio of C and O in the two-grain grain boundaries is 0.37%, and the two-grain grain boundaries further include a new phase, and 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, M is Zr, and the ratio of the area of the new phase at the two-grain boundary to the total area of the two-grain boundary is 1.33%.

In one preferred embodiment of the present invention, the NdFeB magnet material comprises the following components in mass content:
R1: Nd is 29.9% and Dy is 0.2%, and R1 is a rare earth element added during melting and refining.
R2: Tb is 0.6%, and R2 is a 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%,
Fe: 67.67%,
The percentages are the mass percentages of the content of each component relative to the total mass of the neodymium iron boron magnet material,
The neodymium iron boron magnet material includes Nd ₂ Fe ₁₄ B crystal grains and their shell layers, two-grain grain boundaries and grain boundary triangular regions adjacent to the Nd ₂ Fe ₁₄ 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 are mainly distributed in the shell layers, two-grain grain boundaries and grain boundary triangular regions, the area ratio of the grain boundary triangular regions is 2.73%, the grain boundary continuity of the two-grain grain boundaries is 98.07%, the mass ratio of C and O in the grain boundary triangular regions is 0.49%, the mass ratio of C and O in the two-grain grain boundaries is 0.35%, and the two-grain grain boundaries further include a new phase, and 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, M is Nb and Ga, and the ratio of the area of the new phase at the two-grain boundary to the total area of the two-grain boundary is 1.21%.

In one preferred embodiment of the present invention, the NdFeB magnet material comprises the following components in mass content:
R1: Nd is 30.4% and Dy is 0.05%, and R1 is a rare earth element added during melting and refining.
R2: Tb is 0.3%, and R2 is a rare earth element added during grain boundary diffusion;
Co: 0.4%,
Nb: 0.2%,
Cu added during melting and refining: 0.12%
Cu added during grain boundary diffusion: 0.03%
B: 0.99%,
Fe: 67.31%,
The percentages are the mass percentages of the content of each component relative to the total mass of the neodymium iron boron magnet material,
The neodymium iron boron magnet material includes _{Nd2Fe14B crystal} grains and their shell layers, two-grain grain boundaries and grain boundary triangular regions adjacent to the _Nd2Fe14B crystal grains, wherein the heavy rare earth elements in R1 are mainly distributed in _{the Nd2Fe14B crystal} grains, and R2 are mainly distributed in the shell layers, two-grain grain boundaries and grain boundary triangular regions, the area ratio of the grain boundary triangular regions is 2.36%, the grain boundary continuity of the two-grain grain boundaries is 98.12%, the mass ratio of C and O in the grain boundary triangular regions is 0.48%, the mass ratio of C and O in the two-grain grain boundaries is 0.38%, and the two-grain grain boundaries further include a new phase, and its chemical composition is _R79.71 (Fe+ _Co ) _{19.65Cu0.62M 0.02} , R is one or more of Nd, Dy and Tb, M is Nb, and the ratio of the area of the new phase at the two-grain boundary to the total area of the two-grain boundary is 1.08%.

In one preferred embodiment of the present invention, the NdFeB magnet material comprises the following components in mass content:
R1: Nd is 32.1% and Dy is 0.3%, and R1 is a rare earth element added during melting and refining.
R2: Tb is 0.2%, and R2 is a rare earth element added during grain boundary diffusion;
Co: 0.45%,
Nb: 0.3%,
Cu: 0.15%,
B: 1.1%,
Fe: 65.4%,
The percentages are the mass percentages of the content of each component relative to the total mass of the neodymium iron boron magnet material,
The neodymium iron boron magnet material includes _{Nd2Fe14B crystal} grains and their shell layers, two-grain grain boundaries and grain boundary triangular regions adjacent to the _Nd2Fe14B crystal grains, wherein the heavy rare earth elements in R1 are mainly distributed in _{the Nd2Fe14B crystal} grains, and R2 are mainly distributed in the shell layers, two-grain grain boundaries and grain boundary triangular regions, the area ratio of the grain boundary triangular regions is 2.99%, the grain boundary continuity of the two-grain grain boundaries is 98.03%, the mass ratio of C and O in the grain boundary triangular regions is 0.45%, the mass ratio of C and O in the two-grain grain boundaries is 0.4%, and the two-grain grain boundaries further include a new phase, and its chemical composition is _R80.18 (Fe+ _Co ) _{19.16Cu0.62M 0.04} , R is one or more of Nd, Dy and Tb, M is Nb, and the ratio of the area of the new phase at the two-grain boundary to the total area of the two-grain boundary is 0.21%.

In one preferred embodiment of the present invention, the NdFeB magnet material comprises the following components in mass content:
R1: Nd is 29.9% and Dy is 0.2%, and R1 is a rare earth element added during melting and refining.
R2: Tb is 0.6%, and R2 is a 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%,
Fe: 67.74%,
The percentages are the mass percentages of the content of each component relative to the total mass of the neodymium iron boron magnet material,
The neodymium iron boron magnet material includes _{Nd2Fe14B crystal} grains and their shell layers, two-grain grain boundaries and grain boundary triangular regions adjacent to the _Nd2Fe14B crystal grains, wherein the heavy rare earth elements in R1 are mainly distributed in _{the Nd2Fe14B crystal} grains, and R2 are mainly distributed in the shell layers, two-grain grain boundaries and grain boundary triangular regions, the area ratio of the grain boundary triangular regions is 2.54%, the grain boundary continuity of the two-grain grain boundaries is 98.18%, the mass ratio of C and O in the grain boundary triangular regions is 0.44%, the mass ratio of C and O in the two-grain grain boundaries is 0.35%, and the two-grain grain boundaries further include a new phase, and its chemical composition is _R79.4 (Fe+ _Co ) _{19.94Cu0.64M 0.02} , R is one or more of Nd, Dy and Tb, M is Nb and Ga, and the ratio of the area of the new phase at the two-grain boundary to the total area of the two-grain boundary is 0.34%.

In the neodymium iron boron magnet material of the present invention, the range of the total rare earth amount TRE, Co, Cu and M (Ti, Nb, Zr, etc.) elements is rationally controlled in combination with a specific timing for adding heavy rare earth elements, so that the impurity phase is distributed more in the two grain boundaries without concentrating in the grain boundary triangular region, thereby improving the grain boundary continuity and reducing the area of the grain boundary triangular region, which is beneficial for obtaining a higher density and improving the residual magnetic flux density Br of the magnet. In addition, the Tb element is uniformly distributed mainly in the grain boundaries and the main phase shell layer, thereby improving the coercive force Hcj of the magnet.

The present invention further provides an application of the neodymium iron boron magnetic material as described above in the manufacture of permanent magnets.

Here, it is preferable that the permanent magnet is a 54SH, 54UH, or 56SH permanent magnet.

Each preferred embodiment of the present invention can be obtained by arbitrarily combining each of the above preferred conditions while conforming to common knowledge in this field.

All reagents and raw materials used in this invention are commercially available.

The positive and progressive effects of the present invention are as follows:
The NdFeB magnet material of the present invention is based on the existing NdFeB magnet material, by combining a certain content of a number of elements, on the premise of adding a small amount of Co and a small amount of heavy rare earth elements, it can increase the proportion of impurity phases (rare earth oxides, rare earth carbides) in the two-particle grain boundary phase, generate new phases in the two-particle grain boundary, correspondingly improve the continuity of the two-particle grain boundary, reduce the proportion of material phases in the grain boundary triangular region, and correspondingly reduce the area of the grain boundary triangular region, thereby improving the compactness of the NdFeB magnet material, promoting the uniform distribution of Tb element in the grain boundary and the main phase shell layer, and improving the remanence Br, coercive force Hcj, and corresponding temperature stability of the NdFeB magnet material.

Fig. 1 is an EPMA microstructure diagram of the neodymium iron boron magnet material in Example 4. The point indicated by the arrow 1 in the figure is a new phase _Rx (Fe+Co) _{100-x-y-zCuyMz contained} in the grain boundary of two _grains , the position indicated by the arrow 2 is a grain boundary triangular region, and the position indicated by the arrow 3 is a _Nd2Fe14B main _phase .

The present invention will be further described below with reference to examples, but the present invention is not limited to the scope of the described examples. In the following examples, experimental methods for which specific conditions are not specified are selected according to normal methods and conditions or according to product specifications.

1. The raw material composition of the neodymium iron boron magnet material in Examples 1 to 10 of the present invention and Comparative Examples 1 to 4 is shown in Table 1 below.

Table 1. Components and contents (wt%) of the raw material composition of neodymium iron boron magnet material
Note: "/" means that the element is not included. wt% is mass percentage.

2. Manufacturing method of NdFeB magnet material in Example 1 (1) Melting and casting process: Raw materials other than R2 (R2 in Examples 4 and 8 is added in the form of PrCu, and in Examples 4 and 8, the content of Cu added in the grain boundary diffusion process is 0.05 wt% and 0.03 wt%, respectively, and the content of Cu added in the melting and smelting process is 0.03 wt% and 0.12 wt%, respectively) prepared according to the components shown in Table 1 are placed in an alumina crucible, and vacuum melted and smelted in a high-frequency vacuum melting furnace under conditions of a vacuum of 0.05 PaPa and 1500°C. Argon gas is introduced into a medium-frequency vacuum induction rapid solidification melt spinning furnace to cast, and the alloy is quenched to obtain alloy pieces.
(2) Hydrogen crushing and milling process: After evacuating the hydrogen crushing furnace in which the quenched alloy is placed at room temperature, hydrogen gas with a purity of 99.9% is introduced into the hydrogen crushing furnace to maintain the hydrogen gas pressure at 90 kPa, and after sufficient hydrogen absorption, the temperature is raised while evacuating, sufficient dehydrogenation is performed, and then the alloy is cooled and the hydrogen crushed powder is taken out. Here, the hydrogen absorption temperature is room temperature, and the dehydrogenation temperature is 550°C.
(3) Jet mill milling step: The hydrogen-crushed powder is jet milled for 3 hours under conditions of a nitrogen gas atmosphere and a crushing chamber pressure of 0.6 MPa to obtain a fine powder.
(4) Molding step: The jet milled powder is molded in a magnetic field strength of 1.5 T or more.
(5) Sintering process: Each compact is loaded into a sintering furnace and sintered under a vacuum of less than 0.5 Pa at 1030-1090°C for 2-5 hours to obtain a sintered body.
(6) Grain boundary diffusion process: After cleaning the surface of the sintered body, R2 (for example, one or more of Tb alloy or fluoride, Dy alloy or fluoride, and PrCu alloy, of which Cu is added simultaneously in the melting and smelting process and the grain boundary diffusion process) is coated on the surface of the sintered body, and diffused at a temperature of 850°C for 5 to 15 hours, and then cooled to room temperature, and then low-temperature tempering treatment is performed at a temperature of 460 to 560°C for 1 to 3 hours.

The parameters for the manufacturing method of the neodymium iron boron magnet material in Examples 2 to 10 and Comparative Examples 1 to 4 are the same as those in Example 1.

3. Measurement of components: The neodymium iron boron magnet materials in Examples 1 to 10 and Comparative Examples 1 to 4 were measured using an inductively coupled plasma optical emission spectrometer (ICP-OES). The measurement results are shown in Table 2 below.

Table 2. Neodymium iron boron magnet components and content (wt%)
Note: "/" means that the element is not included. wt% is mass percentage.
Effect Example 1

The microstructure and magnetic property detection of the NdFeB magnet materials in Examples 1 to 10 and Comparative Examples 1 to 4 are as follows:
1. Magnetic property test: The sintered magnets were subjected to magnetic property detection using a PFM-14 magnetic property tester manufactured by Hirs, UK. The detected magnetic properties include the residual magnetic flux density at 20°C and 120°C, the coercive force at 20°C and 120°C, and the corresponding temperature coefficient of residual magnetic flux density. Here, the formula for calculating the temperature coefficient of residual magnetic flux density is (Br _{high temperature} - Br _{room temperature} ) / (Br _{room temperature} (high temperature - room temperature)) x 100%, and the test results are shown in Table 3 below.
2. Detection by FE-EPMA: The vertically oriented surface of the neodymium iron boron magnet material was polished and detected by a field emission electron probe microanalyzer (FE-EPMA) (JEOL, 8530F). The area ratio of the grain boundary triangular region, the continuity of the two grain grain boundaries, the mass ratio of C and O, and the new phase were tested. The test results are shown in Table 3 below.

The continuity of the two-particle grain boundary is calculated from the backscattering image of the EPMA, and the mass ratios of C and O and new phases in the two-particle grain boundary and grain boundary triangular regions are measured by elemental analysis of the EPMA.

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

The continuity (%) of a two-grain grain boundary refers to the ratio of the length occupied by phases other than voids at the grain boundary (phases such as B-rich phase, rare earth-rich phase, rare earth oxides, rare earth carbides, etc.) to the total length of the grain boundary.

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

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

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

Table 3
Note: "x" indicates that _the two-grain grain boundary phase does not contain any new phase with the chemical composition _Rx (Fe+Co _{) 100-xyzCuyMz} .

As can be seen from Table 3 above, in the present invention, when a small amount of Co and heavy rare earth elements are added, it is possible to reach a level equivalent to the current level of adding a large amount of Co and heavy rare earth elements. In addition, because the rare earth content of the grain boundary is high, C and O are distributed more in the grain boundary and exist in the form of rare earth carbides and rare earth oxides, respectively. Based on the fact that the values of Comparative Examples 1 to 4 are all reduced compared to the value obtained by subtracting the "mass ratio (%) of C and O in the grain boundary of two particles" from the "mass ratio (%) of C and O in the grain boundary triangular region" in Examples 1 to 10, it can be concluded that the impurity phase (rare earth carbides and rare earth oxides) migrates from the grain boundary triangular region to the grain boundary of two particles, and a new phase is generated, which explains the reason why the continuity of the grain boundary of two particles is improved from the mechanism.
Effect Example 2

As shown in Figure 1, the EPMA microstructure diagram of the NdFeB magnet material produced by Example 4 is shown. The point indicated by the arrow 1 in the figure is the new phase _Rx (Fe+Co) _{100-x-y- zCuyMz} contained in the two-grain grain boundary (French gray _area ), the position indicated by the arrow 2 is the grain boundary triangular region (silver white area), and the position indicated by the arrow 3 is _{the Nd2Fe14B} main phase (charcoal gray area). Combining the data in Table 3, it can be further seen that the area of the grain boundary triangular region is smaller than that of ordinary magnet materials.

Claims (10)

A neodymium iron boron magnet material, comprising the following components in the following mass content:
R: 28 to 33%, R includes R1 and R2, R1 includes Nd and Dy, the content of Dy is 0.3% or less but not 0 , R2 includes Tb, and the content of R2 is 0.2 to 1%,
Co: <0.5%, but not 0;
M: ≦0.4%, but not 0, and 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 to 1.5%,
Fe: 60 to 70%,
Percentage means the mass percentage of each component relative to the total mass of the neodymium iron boron magnet material;
The neodymium iron boron magnet material includes Nd ₂ Fe ₁₄ B crystal grains and their shell layers, two-grain grain boundaries and grain boundary triangular regions adjacent to the Nd ₂ Fe ₁₄ 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 are mainly distributed in the shell layer, the two-particle grain boundary and the grain boundary triangular region, and the area ratio of the grain boundary triangular region is 1.8-2.99%;
The grain boundary continuity of the two grains is 96% or more;
The two-grain boundary further includes a new phase having a chemical composition R _x (Fe+Co) _100-x-y-z Cu _y M _z , where 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, and z is less than or equal to 0.1, but not 0;
wherein the ratio of the area of the two-grain boundary of the new phase to the total area of the two-grain boundary is 0.2 to 2.6%;
The mass ratio of C and O in the grain boundary triangular region is 0.4 to 0.5%, and the mass ratio of C and O in the two-particle grain boundary is 0.3 to 0.5%.
A neodymium iron boron magnet material. the area ratio of the grain boundary triangular region is 1.96 to 2.99%,
The grain boundary continuity is 97% or more,
The mass ratio of C to O in the grain boundary triangular region is 0.41 to 0.49%,
The mass ratio of C and O at the two-particle grain boundary is 0.3 to 0.4% ,
In the neodymium iron boron magnet material, the content of R is 29 to 32.6%, and the percentage is a mass percentage relative to the total mass of the neodymium iron boron magnet material ;
The content of R2 is 0.2 to 0.9%,
In the R2, the content of Tb is 0.2% to 0.9%,
The Co content is 0.45% or less, but not 0,
The content of M is 0.08 to 0.35%,
The neodymium iron boron magnet material further includes Al, and the content of Al is 0.2% or less but not 0;
The Cu content is 0.05 to 0.15%, or 0.08% or less, but not 0;
The content of B is 0.97 to 1.1%;
The Fe content is 65 to 70% .
2. The neodymium iron boron magnet material according to claim 1 . The grain boundary continuity is 98% or more,
The mass ratio of C to O in the grain boundary triangular region is 0.41 to 0.48%,
the mass ratio of C to O at the two-particle grain boundary is 0.34 to 0.4;
In the new phase having a chemical composition of R _x (Fe+Co) _100-x-y-z Cu _y M _z , x is 78.89-80.8, y is 0.55-0.66, z is 0.02-0.06, and the ratio of the area of the two-particle boundary of the new phase to the total area of the two-particle boundary is 0.34-2.55%;
In the neodymium iron boron magnet material, the content of R is 29 to 31%,
R1 further includes one or more of Pr, Ho, Tb, Gd, and Y;
When R1 contains Pr, the Pr is added in the form of PrNd, or in the form of a mixture of pure Pr and pure Nd, or in the form of a combination of "a mixture of PrNd, pure Pr, and pure Nd", where, when added in the form of PrNd, Pr:Nd is 25:75 or 20:80, and when added in the form of a mixture of pure Pr and pure Nd, or in the form of a combination of a mixture of PrNd, pure Pr, and Nd, the Pr content is 0.1 to 2%;
The content of R2 is 0.2 to 0.8%,
R2 further includes one or more of Pr, Dy, Ho, and Gd;
When R2 contains Pr, the Pr content is 0.2% or less,
When R2 contains Dy, the content of Dy is 0.3% or less,
The Co content is 0.05 to 0.4% .
When the M contains Ti, the content of the Ti is 0.05 to 0.3%;
When the M contains Zr, the content of Zr is 0.08 to 0.35%,
When the M contains Nb, the content of the Nb is 0.05 to 0.3%,
In the neodymium iron boron magnet material, the M further includes one or more of Bi, Sn, Zn, Ga, In, Au, and Pb;
When the M contains Ga, the Ga content is 0.2% or more, or 0.01% or less, but not 0;
When the M contains Ga and Ga≧0.2%, in the composition of the M element, Ti+Nb≦0.07%,
The content of Al is 0.03 to 0.2%,
When the M contains Ga and Ga≦0.01%, in the composition of the M element, Al+Ga+Cu≦0.11%,
The method of adding Cu includes adding Cu during melting or grain boundary diffusion,
When the Cu is added during melting and smelting, the content of Cu added during the melting and smelting is 0.03 to 0.15%;
When the Cu is added during grain boundary diffusion, the Cu is added in the form of a PrCu alloy.
3. The neodymium iron boron magnet material according to claim 2 . The neodymium iron boron magnet material comprises the following components in mass content:
R: 29-32.6%, R includes R1 and R2, R1 includes Nd and Dy, the content of Dy is 0.3% or less but not 0, R1 is a rare earth element added during melting and smelting, the content of R2 is 0.2-1%, R2 includes Tb, and R2 is a rare earth element added during grain boundary diffusion,
Co: 0.05 to 0.45%,
M: 0.08 to 0.35%, and the type of M includes one or more of Ti, Nb, and Zr;
Cu: 0.05 to 0.15%,
B: 0.97 to 1.1%,
Fe: 65 to 70% ,
The neodymium iron boron magnet material includes Nd ₂ Fe ₁₄ B crystal grains and their shell layers, two-grain grain boundaries and grain boundary triangular regions adjacent to the Nd ₂ Fe ₁₄ 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 are mainly distributed in the shell layers, two-grain grain boundaries and grain boundary triangular regions, the area ratio of the grain boundary triangular regions is 1.96-2.99%, the grain boundary continuity of the neodymium iron boron magnet material is 97% or more, the mass ratio of C and O in the grain boundary triangular regions is 0.41-0.49%, the mass ratio of C and O in the two-grain grain boundaries is 0.3-0.4%, and the chemical composition of the new phase in the two-grain grain boundaries is R _x (Fe+Co) _100-x-y-z Cu _y M _z , x is 78.89 to 80.8, y is 0.55 to 0.66, z is 0.02 to 0.06, and the ratio of the area of the new phase at the two-grain boundary to the total area of the two-grain boundary is 0.21 to 2.6%,
Alternatively, the neodymium iron boron magnet material comprises the following components in mass content:
R: 29-31%, R includes R1 and R2, R1 includes Nd and Dy, the amount of Dy used is 0.1-0.2%, R1 is a rare earth element added during melting and smelting, the content of R2 is 0.2-0.8%, R2 includes Tb, and R2 is a rare earth element added during grain boundary diffusion,
Co: 0.05 to 0.4%,
M: 0.1 to 0.15%, the type of M including one or more of Ti, Nb and Zr;
Cu: 0.08% or less, but not 0; B: 0.97-1.1%;
Fe: 65 to 70% ,
The neodymium iron boron magnet material includes Nd ₂ Fe ₁₄ B crystal grains and their shell layers, two-grain grain boundaries and grain boundary triangular regions adjacent to the Nd ₂ Fe ₁₄ 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 are mainly distributed in the shell layers, two-grain grain boundaries and grain boundary triangular regions, the area ratio of the grain boundary triangular regions is 1.96-2.8%, the grain boundary continuity of the neodymium iron boron magnet material is 98% or more, the mass ratio of C and O in the grain boundary triangular regions is 0.41-0.48%, the mass ratio of C and O in the two-grain grain boundaries is 0.34-0.4%, and the chemical composition of the new phase in the two-grain grain boundaries is R _x (Fe+Co) _100-x-y-z Cu _y M _z , x is 78.89 to 80.8, y is 0.55 to 0.66, z is 0.02 to 0.06, and the ratio of the area of the new phase at the two-grain grain boundary to the total area of the two-grain grain boundary is 0.34 to 2.55%.
2. The neodymium iron boron magnet material according to claim 1 . 2. A raw material composition for a neodymium iron boron magnet material according to claim 1, comprising the following components in the following mass contents:
R: 28-33%, R is a rare earth element, R includes R1 and R2, R1 is a rare earth element added during melting and refining, R1 includes Nd and Dy, the content of Dy is 0.3% or less but not 0,
The R2 is a rare earth element added during grain boundary diffusion, the R2 contains Tb, and the content of the R2 is 0.2 to 1%;
Co: <0.5%, but not 0;
M: ≦0.4%, but not 0, and 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 to 1.1%,
Fe: 60 to 70%,
Percentages are the mass percentages of the content of each component relative to the total mass of the raw material composition;
A raw material composition for a neodymium iron boron magnet material. The content of R in the raw material composition is 29 to 32.6%;
The content of R2 is 0.2 to 0.9%,
In the R2, the Tb content is 0.2 to 0.9%,
The Co content is 0.45% or less, but not 0,
The content of M is 0.08 to 0.35%,
The raw material composition further contains Al, and the content of Al is 0.2% or less but not 0,
The Cu content is 0.05 to 0.15%, or 0.08% or less, but not 0;
The content of B is 0.97 to 1.1%;
The Fe content is 65 to 70%.
6. The raw material composition for a neodymium iron boron magnet material according to claim 5. The content of R in the raw material composition is 29 to 31%;
In the R1, the content of Dy is 0.1 to 0.2%,
R1 further includes one or more of Pr, Ho, Tb, Gd, and Y;
When R1 contains Pr, the Pr is added in the form of PrNd, or in the form of a mixture of pure Pr and pure Nd, or in the form of a combination of "a mixture of PrNd, pure Pr, and pure Nd", where, when added in the form of PrNd, Pr:Nd is 25:75 or 20:80, and when added in the form of a mixture of pure Pr and Nd, or in the form of a combination of "a mixture of PrNd, pure Pr, and Nd", the Pr content is 0.1 to 2 wt%;
When the R1 contains Ho, the content of Ho is 0.1 to 0.2%,
When R1 contains Gd, the content of Gd is 0.1 to 0.2%;
When the R1 contains Y, the content of Y is 0.1 to 0.2%;
The content of R2 is 0.2 to 0.8%,
In the R2, the Tb content is 0.2 to 0.8%,
R2 further includes one or more of Pr, Dy, Ho, and Gd;
When R2 contains Pr, the content of Pr is 0.2% or less but not 0;
When R2 contains Dy, the content of Dy is 0.3% or less but not 0;
When R2 contains Ho, the content of Ho is 0.2% or less but not 0;
When R2 contains Gd, the content of Gd is 0.2% or less but not 0;
The Co content is 0.05 to 0.4%.
When the M contains Ti, the content of Ti is 0.05 to 0.3%;
When the M contains Zr, the content of Zr is 0.08 to 0.35%,
When the M contains Nb, the content of the Nb is 0.05 to 0.3%,
In the raw material composition, the M further contains one or more of Bi, Sn, Zn, Ga, In, Au, and Pb,
When the M element contains Ga, the content of Ga is 0.2% or more, or 0.01% or less, but not 0;
When the M element contains Ga and Ga≧0.2%, Ti+Nb≦0.07% in the composition of the M element;
The content of Al is 0.03 to 0.2%,
When the M contains Ga and Ga≦0.01%, in the composition of the M element, Al+Ga+Cu≦0.11%,
The method of adding Cu includes adding Cu during melting or grain boundary diffusion,
When the Cu is added during melting and smelting, the content of Cu added during the melting and smelting is 0.05 to 0.15%;
When the Cu is added during grain boundary diffusion, the Cu is added in the form of a PrCu alloy.
7. The raw material composition for a neodymium iron boron magnet material according to claim 6. The raw material composition of the neodymium iron boron magnet material comprises the following components in the following mass contents:
R: 29-32.6%, R includes R1 and R2, R1 includes Nd and Dy, the amount of Dy used is 0.3% or less but not 0, R1 is a rare earth element added during melting and smelting, the content of R2 is 0.2-1%, R2 includes Tb, and R2 is a rare earth element added during grain boundary diffusion,
Co: 0.05 to 0.45%,
M: 0.08 to 0.35%, the type of M including one or more of Ti, Nb and Zr;
Cu: 0.05 to 0.15%,
B: 0.97 to 1.1%,
Fe: 65-70%,
The percentages are the mass percentages of the content of each component relative to the total mass of the raw material composition;
Alternatively, the raw material composition of the neodymium iron boron magnet material comprises the following components in the following mass contents:
R: 29-31%, R includes R1 and R2, R1 includes Nd and Dy, the amount of Dy used is 0.1-0.2%, R1 is a rare earth element added during melting and smelting, the content of R2 is 0.2-0.8%, R2 includes Tb, and R2 is a rare earth element added during grain boundary diffusion,
Co: 0.05 to 0.4%,
M: 0.1 to 0.15%, the type of M including one or more of Ti, Nb and Zr;
Cu: 0.08% or less, but not 0;
B: 0.97 to 1.1%,
Fe: 65-70%,
Percentages are the mass percentages of the content of each component relative to the total mass of the raw material composition;
6. The raw material composition for a neodymium iron boron magnet material according to claim 5. A method for producing a neodymium-iron-boron magnet material, the method being carried out using the raw material composition according to any one of claims 5 to 8, the method being a diffusion method, in which the R1 element is added in a melting and smelting process, and the R2 element is added in a grain boundary diffusion process.
A method for producing a neodymium iron boron magnet material. The manufacturing method includes the following steps:
The elements other than R2 in the raw material composition of the neodymium-iron-boron magnet material are melted and refined, milled, molded, and sintered to obtain a sintered body, and then the mixture of the sintered body and R2 is subjected to grain boundary diffusion;
Here, the melting and smelting operation includes melting, smelting and casting the elements other than R2 in the neodymium-iron-boron magnet material through an ingot process and a strip casting process to obtain alloy flakes;
The temperature of the smelting is 1300 to 1700°C,
wherein the milling comprises hydrogrinding milling or jet milling;
The hydrogen crushing and milling process includes hydrogen absorption, dehydrogenation and cooling, the hydrogen absorption temperature is 20-200°C, the dehydrogenation temperature is 400-650°C, and the hydrogen absorption pressure is 50-600kPa;
The jet milling is carried out under a pressure of 0.1 to 2 MPa, the gas flow in the jet milling is nitrogen gas, and the time of the jet milling is 2 to 4 h;
Here, the molding is a magnetic field molding method, and the magnetic field strength of the magnetic field molding method is 1.5 T or more;
The sintering is carried out under a vacuum condition of less than 0.5 Pa,
The sintering temperature is 1000 to 1200° C.
The sintering time is 0.5 to 10 h,
wherein the method further comprises a coating operation of R2 prior to the grain boundary diffusion;
The R2 is coated in the form of a fluoride or a low melting point alloy, and when Dy is further included, the Dy is coated in the form of a Dy fluoride;
When Pr is further included, Pr is added in the form of a PrCu alloy;
Here, the temperature of the grain boundary diffusion treatment is 800 to 1000° C.
The grain boundary diffusion treatment time is 5 to 20 hours,
Here, after the grain boundary diffusion, a low-temperature tempering treatment is further performed, the temperature of the low-temperature tempering treatment is 460 to 560 ° C, and the time of the low-temperature tempering is 1 to 3 h.
10. The method for producing a neodymium iron boron magnet material according to claim 9.