Neodymium-iron-boron magnet material, method for producing same, and electronic device including same

Abstract

The application discloses a neodymium-iron-boron magnet material and a preparation method thereof, and an electronic device containing the same. The neodymium-iron-boron magnet material comprises the following components: R: 28.0-32.0 wt%, R comprises Nd, R further comprises Tb and / or Dy, the content of Nd is greater than or equal to 27.0 wt%; Cu: 0.16-0.40 wt%; Ga: 0.07-0.24 wt%; Al: less than or equal to 0.10 wt%; B: 0.96-1.10 wt%; Co: 0.15-2.0 wt%; M: 0.10-0.25 wt%, M is selected from at least one of Ti, Zr and Nb; and a phase with a chemical composition of R w Fe 100‑w‑x‑y‑z Co x Cu y Ga z is contained in the two-particle grain boundary of the neodymium-iron-boron magnet material. The neodymium-iron-boron magnet material in the application can realize a significant improvement in coercive force under the condition of adding a small amount of heavy rare earth element Tb, while maintaining a high remanence and squareness.

Description

Technical Field

[0001] This invention relates to a neodymium iron boron magnet material, its preparation method, and electronic devices containing the same. Background Technology

[0002] Neodymium iron boron (NdFeB) permanent magnets are an important class of rare-earth functional materials with excellent comprehensive magnetic properties, and are widely used in electric vehicles, air conditioning compressors, elevators, wind power, the electronics industry, and many other fields. With the growth of the new energy vehicle market and the demand for high-efficiency energy-saving appliances, the miniaturization and high energy efficiency of motors have become new focuses. To minimize motor size and maximize output power, magnets must possess high energy density, i.e., high remanence. Simultaneously, these high-temperature applications place higher demands on the coercivity performance of sintered Nd-Fe-B magnets.

[0003] Grain boundary diffusion is an effective method to improve the coercivity of magnets. It involves attaching a diffusion source material (including inorganic rare earth compounds, rare earth metals, or rare earth alloys) containing heavy rare earth elements (RH, Dy, or Tb) to the surface of a sintered NdFeB magnet. Then, high-temperature diffusion is performed at a temperature above the melting point of the NdFeB-rich phase at the grain boundaries and below the magnet's sintering temperature, allowing RH to penetrate along the grain boundaries into the interior of the magnet. 14 A highly anisotropic field (Nd,Dy)2Fe is formed on the surface of the B-phase grains. 14 B or (Nd,Tb)2Fe 14 B magnetic hard layer, thereby improving the coercivity of the magnet.

[0004] Chinese patent document CN111223626A discloses a neodymium iron boron permanent magnet material with Nd 28.7wt%, Dy 0.05wt%, Pr 0.1wt%, Tb 1.0wt%, Ga 0.05wt%, Cu 0.05wt%, Al 0.1wt%, B 0.99wt%, and Fe 69.06wt%, exhibiting a remanence of 14.51kGs and a coercivity of 25.23kOe. However, the coercivity performance of this material currently cannot meet the demagnetization requirements of motors in specific fields, and the addition of the heavy rare earth element Tb is relatively large, resulting in high raw material costs.

[0005] Therefore, providing an RTB-based permanent magnet material with low content of heavy rare earth elements and high coercivity and high remanence is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0006] This invention addresses the deficiency in existing technologies where neodymium iron boron (NdFeB) magnet materials cannot simultaneously achieve high levels of remanence and coercivity. It provides a NdFeB magnet material, its preparation method, and an electronic device containing it. By controlling the types and contents of elements in the NdFeB magnet material, this invention enables the preparation of magnet materials with high remanence, coercivity, and good squareness.

[0007] This invention provides a raw material composition for neodymium iron boron magnets, comprising, by weight percentage, the following components:

[0008] R: 28.0-32.0 wt%, where R is a rare earth element, including R1 and R2; R1 is a rare earth element added during smelting, including Nd, and further including at least one of Tb and Dy, wherein the Nd content is not less than 27.0 wt%; R2 is a rare earth element added during grain boundary diffusion, including Tb and / or Dy, and the content of R2 is 0.1-0.8 wt%.

[0009] Cu: 0.16-0.40 wt%;

[0010] Ga: 0.07-0.24 wt%;

[0011] Al: ≤0.10wt%;

[0012] B: 0.96-1.10 wt%;

[0013] Co: 0.15-2.0 wt%;

[0014] M: 0.10-0.25 wt%, M is selected from at least one of Ti, Zr and Nb;

[0015] The balance consists of Fe and unavoidable impurities.

[0016] In this invention, the content of R is preferably 29.5-31.5 wt%, for example 30.24 wt%, 30.28 wt%, 30.35 wt%, 30.36 wt%, 30.43 wt%, 30.44 wt%, 30.45 wt%, 30.46 wt%, 30.48 wt%, 30.55 wt%, 30.66 wt%, or 30.95 wt%, more preferably 30.0-31.0 wt%; wt% refers to the mass percentage in the raw material composition.

[0017] In this invention, the content of R1 is preferably 29.5-31.5 wt%, for example 29.8 wt%, 29.9 wt%, 30.0 wt%, 30.2 wt%, or 30.5 wt%, more preferably 29.5-30.5 wt%; wt% refers to the mass percentage in the raw material composition.

[0018] In this invention, the Nd content in R1 of the raw material composition is preferably 27.5-30.0 wt%, for example 28.3 wt%, 29.0 wt%, 29.2 wt%, or 30.0 wt%, more preferably 28.5-29.5 wt%; wt% refers to the mass percentage in the raw material composition.

[0019] In this invention, R1 can be selected from Nd and Dy, or it can also be selected from Nd and Tb.

[0020] In this invention, when R1 contains Dy, the content of Dy is preferably less than 1.5 wt% but not 0, for example 0.5 wt%, 1.0 wt% or 1.5 wt%, more preferably 0.5-1.0 wt%; wt% refers to the mass percentage in the raw material composition.

[0021] In this invention, when R1 contains Tb, the content of Tb is preferably less than 1.5 wt% but not 0, for example 0.9 wt% or 1.0 wt%, more preferably 0.5-1.0 wt%; wt% refers to the mass percentage in the raw material composition.

[0022] In this invention, the content of R2 is preferably 0.2-0.7 wt%, for example 0.24 wt%, 0.36 wt%, 0.43 wt%, 0.44 wt%, 0.45 wt%, 0.46 wt%, 0.48 wt%, or 0.55 wt%, more preferably 0.25-0.60 wt%; wt% refers to the mass percentage in the raw material composition.

[0023] In this invention, R2 can be selected from Tb or Dy.

[0024] In this invention, when R2 contains Dy, the content of Dy is preferably 0.2-0.7 wt%, for example 0.55 wt%, more preferably 0.20-0.60 wt%; wt% refers to the mass percentage in the raw material composition.

[0025] In this invention, when R2 contains Tb, the content of Tb is preferably 0.2-0.7 wt%, for example 0.24 wt%, 0.36 wt%, 0.43 wt%, 0.44 wt%, 0.45 wt%, 0.46 wt%, or 0.48 wt%, more preferably 0.25-0.60 wt%; wt% refers to the mass percentage in the raw material composition.

[0026] In some preferred embodiments of the present invention, R1 is selected from Nd and Tb, and R2 is selected from Tb or Dy.

[0027] In some preferred embodiments of the present invention, R1 is selected from Nd and Dy, and R2 is selected from Tb.

[0028] In some preferred embodiments of the present invention, in the raw material composition of the neodymium iron boron magnet material, Dy ≤ 0.24 wt%; wt% refers to the mass percentage in the raw material composition of the neodymium iron boron magnet material.

[0029] In this invention, the content of Cu is preferably 0.20-0.35 wt%, for example 0.20 wt%, 0.22 wt%, 0.25 wt%, 0.26 wt%, 0.27 wt%, 0.28 wt%, 0.29 wt%, 0.30 wt%, 0.31 wt%, or 0.34 wt%, more preferably 0.25-0.35 wt%; wt% refers to the mass percentage in the raw material composition.

[0030] In this invention, the Cu is preferably added during smelting and / or during grain boundary diffusion. When the Cu is added during grain boundary diffusion, the content of Cu added during grain boundary diffusion is preferably 0.03-0.10 wt%, for example, 0.05 wt%.

[0031] In this invention, the content of Ga is preferably 0.10-0.22 wt%, for example 0.11 wt%, 0.18 wt%, 0.19 wt%, 0.20 wt%, or 0.21 wt%, more preferably 0.15-0.20 wt%; wt% refers to the mass percentage in the raw material composition.

[0032] In this invention, the content of Al is preferably below 0.08 wt%, but not 0, and more preferably 0.03-0.07 wt%, for example 0.03 wt%, 0.04 wt%, 0.05 wt%, or 0.06 wt%; wt% refers to the mass percentage in the raw material composition.

[0033] In this invention, the content of B is preferably 0.97-1.05 wt%, for example 0.99 wt%, 1.00 wt%, or 1.01 wt%, more preferably 0.98-1.02 wt%; wt% refers to the mass percentage in the raw material composition.

[0034] In this invention, the content of Co is preferably 0.30-2.0 wt%, for example 0.38 wt%, 0.55 wt%, 0.58 wt%, 0.60 wt%, 0.61 wt%, 0.62 wt%, 0.64 wt%, 0.85 wt%, 1.00 wt%, 1.50 wt%, and 2.00 wt%; wt% refers to the mass percentage in the raw material composition.

[0035] In this invention, M can be selected from Ti.

[0036] In this invention, the content of M can be 0.15-0.25 wt%, for example 0.18 wt%, 0.19 wt%, 0.20 wt%, or 0.21 wt%.

[0037] In some preferred embodiments of the present invention, the raw material composition of the neodymium iron boron magnet material comprises the following components, by weight percentage:

[0038] R: 29.5-31.5 wt%, where R is a rare earth element, including R1 and R2; R1 is a rare earth element added during smelting, and R1 is selected from Nd and Tb, wherein the Nd content is not less than 27.0 wt%; R2 is a rare earth element added during grain boundary diffusion, and R2 is selected from Tb or Dy, wherein the content of R2 is 0.2-0.7 wt%.

[0039] Cu: 0.20-0.35 wt%;

[0040] Ga: 0.07-0.22 wt%;

[0041] Al: ≤0.10wt%;

[0042] B: 0.96-1.10 wt%;

[0043] Co: 0.15-2.0 wt%;

[0044] M: 0.10-0.25 wt%, M is selected from at least one of Ti, Zr and Nb;

[0045] The balance consists of Fe and unavoidable impurities.

[0046] In some preferred embodiments of the present invention, the raw material composition of the neodymium iron boron magnet material comprises the following components, by weight percentage:

[0047] R: 29.5-31.5 wt%, where R is a rare earth element, including R1 and R2; R1 is a rare earth element added during smelting, and R1 is selected from Nd and Dy, wherein the Nd content is not less than 27.0 wt%; R2 is a rare earth element added during grain boundary diffusion, and R2 is selected from Tb, wherein the content of R2 is 0.2-0.7 wt%.

[0048] Cu: 0.20-0.35 wt%;

[0049] Ga: 0.07-0.22 wt%;

[0050] Al: ≤0.10wt%;

[0051] B: 0.96-1.10 wt%;

[0052] Co: 0.15-2.0 wt%;

[0053] M: 0.10-0.25 wt%, M is selected from at least one of Ti, Zr and Nb;

[0054] The balance consists of Fe and unavoidable impurities.

[0055] In some preferred embodiments of the present invention, the raw material composition of the neodymium iron boron magnet material comprises, by weight percentage, the components shown in any of the following formulations 1-15:

[0056]

[0057]

[0058] The present invention also provides a method for preparing neodymium iron boron magnet material, which uses the raw material composition described above. The preparation method is a conventional diffusion method in the art, wherein the R1 element is added in the melting step and the R2 element is added in the grain boundary diffusion step.

[0059] In this invention, the preparation method preferably includes the following steps: melting, pulverizing, molding, and sintering the elements other than R2 in the raw material composition of the above-mentioned neodymium iron boron magnet material to obtain a sintered body, and then diffusing the mixture of the sintered body and R2 through grain boundaries.

[0060] The melting operation and conditions can be conventional melting processes in the field. Generally, the elements other than R2 in the raw material composition of the NdFeB magnet material are melted and cast using ingot casting and rapid solidification processes to obtain alloy sheets.

[0061] The melting temperature can be 1400-1600℃, preferably 1450-1550℃, for example 1520℃.

[0062] The melting environment can be a vacuum of 0.05 Pa.

[0063] The smelting equipment is generally a medium-frequency vacuum melting furnace, such as a medium-frequency vacuum induction rapid solidification belt spinning furnace. The powdering operation and conditions can be conventional powdering processes in the art, generally including hydrogen crushing and / or air jet milling.

[0064] The hydrogen-based powdering process generally includes hydrogen absorption, dehydrogenation, and cooling. The temperature for hydrogen absorption is generally 20-200℃. The temperature for dehydrogenation is generally 400-650℃, preferably 500-600℃, for example, 550℃. The pressure for hydrogen absorption is generally 50-600 kPa, preferably 60-300 kPa, for example, 90 kPa.

[0065] The airflow milling process is generally carried out under conditions of 0.1-2 MPa, preferably 0.5-0.7 MPa. The airflow used in the airflow milling process can be, for example, nitrogen. The milling time can be 2-4 hours, for example, 3 hours.

[0066] The molding operation and conditions can be conventional molding processes in the art, such as magnetic field molding. The magnetic field strength in the magnetic field molding method is generally above 1.5T.

[0067] The sintering operation and conditions can be conventional sintering processes in the art.

[0068] The sintering can be carried out under a vacuum of less than 0.5 Pa.

[0069] The sintering temperature can be 1000-1200℃, preferably 1050-1100℃, for example 1080℃.

[0070] The sintering time can be 0.5-10h, preferably 3-6h, for example 6h.

[0071] As those skilled in the art will know, the coating operation of R2 is generally included before the grain boundary diffusion described herein.

[0072] In this invention, the operation and conditions of the grain boundary diffusion treatment can be conventional grain boundary diffusion processes in the art.

[0073] The temperature for grain boundary diffusion can be 800-1000℃, for example 900℃.

[0074] The time for grain boundary diffusion can be 5-20 hours, preferably 10-15 hours.

[0075] After the grain boundary diffusion, a low-temperature tempering treatment is performed according to conventional practices in the art. The temperature of the low-temperature tempering treatment is generally 460-560℃. The low-temperature tempering time is generally 1-5 hours.

[0076] The present invention also provides a neodymium iron boron magnet material prepared by the above preparation method.

[0077] The present invention also provides a neodymium iron boron magnet material, which comprises the following components by weight percentage: R: 28.0-32.0 wt%, wherein R is a rare earth element, wherein R includes Nd, and wherein R further includes at least one of Tb and Dy, wherein the Nd content is not less than 27.0 wt%.

[0078] Cu: 0.16-0.40 wt%;

[0079] Ga: 0.07-0.24 wt%;

[0080] Al: ≤0.10wt%;

[0081] B: 0.96-1.10 wt%;

[0082] Co: 0.15-2.0 wt%;

[0083] M: 0.10-0.25 wt%, M is selected from at least one of Ti, Zr and Nb;

[0084] The balance consists of Fe and unavoidable impurities;

[0085] The neodymium iron boron magnet material contains Nd2Fe 14 B grains and their shells, adjacent to the Nd2Fe 14 Two-grain boundaries and grain boundary triangular regions of B grains;

[0086] The two-grain boundary of the neodymium iron boron magnet material includes a chemical composition of R w Fe 100-w-x-y-z Co x Cu y Ga z The phases are defined as follows: w is 55.0-65.0%, x is 0.30-1.20%, y is 0.35-0.65%, z is 0.2-0.4%, and the percentages refer to the atomic percentages in the phases.

[0087] During the research and development process, the inventors discovered that the chemical composition is R w Fe 100-w-x-y-z Co x Cu y Ga zThe formation of the phase effectively reduces the area of ​​the grain boundary triangle, improves the grain boundary continuity, and lowers the dissolution temperature of the grain boundary phase. It can more significantly improve the fluidity of the grain boundary phase and improve the distribution of the grain boundary phase, thereby greatly improving the coercivity of NdFeB materials by enhancing the demagnetizing coupling ability of the grain boundary phase.

[0088] In some preferred embodiments of the present invention, R includes R1 and R2; R1 includes Nd, and R1 further includes at least one of Tb and Dy, wherein the Nd content is not less than 27.0 wt%; R2 includes Tb and / or Dy, and the content of R2 is 0.1-0.8 wt%; wt% refers to the mass percentage in the NdFeB magnet material.

[0089] When R includes R1 and R2, the heavy rare earth elements in R1 are mainly distributed in Nd2Fe. 14 B grains, R2 are mainly distributed in the shell, two-grain boundaries and grain boundary triangles.

[0090] In this invention, "the heavy rare earth elements in R1 are mainly distributed in Nd2Fe". 14 "B grains" can be understood as the heavy rare earth elements in R1, caused by conventional melting and sintering processes in this field, being mainly distributed (generally referring to more than 90 wt%) in Nd2Fe. 14 B grains, with a small amount distributed at grain boundaries. "R2 is mainly distributed in the shell" can be understood as R2 caused by conventional grain boundary diffusion processes in the art being mainly distributed in (generally referring to 90 wt% in Nd2Fe) grains. 14 The shell and grain boundaries (two-grain grain boundaries and grain boundary triangular regions) of B grains, a small portion of which also diffuses into Nd2Fe. 14 In B grains, for example in Nd2Fe 14 The outer edge of the B grain.

[0091] In this invention, the content of R is preferably 29.5-31.5 wt%, for example 30.24 wt%, 30.28 wt%, 30.35 wt%, 30.36 wt%, 30.43 wt%, 30.44 wt%, 30.45 wt%, 30.46 wt%, 30.48 wt%, 30.55 wt%, 30.66 wt%, or 30.95 wt%, more preferably 30.0-31.0 wt%; wt% refers to the mass percentage in the neodymium iron boron magnet material.

[0092] In this invention, the Nd content in the neodymium iron boron magnet material is preferably 27.5-30.0 wt%, for example 28.3 wt%, 29.0 wt%, 29.2 wt%, or 30.0 wt%, more preferably 28.5-29.5 wt%; wt% refers to the mass percentage in the neodymium iron boron magnet material.

[0093] In this invention, when R includes R1 and R2, the content of R1 in the neodymium iron boron magnet material is preferably 29.5-31.5 wt%, for example 29.8 wt%, 29.9 wt%, 30.0 wt%, 30.2 wt%, or 30.5 wt%, more preferably 29.5-30.5 wt%; wt% refers to the mass percentage in the neodymium iron boron magnet material.

[0094] In this invention, R1 can be selected from Nd and Dy, or it can also be selected from Nd and Tb.

[0095] In this invention, when R1 contains Dy, the content of Dy is preferably less than 1.5 wt% but not 0, for example 0.5 wt%, 1.0 wt% or 1.5 wt%, more preferably 0.5-1.0 wt%; wt% refers to the mass percentage in the neodymium iron boron magnet material.

[0096] In this invention, when R1 contains Tb, the content of Tb is preferably less than 1.5 wt% but not 0, for example 0.9 wt% or 1.0 wt%, more preferably 0.5-1.0 wt%; wt% refers to the mass percentage in the neodymium iron boron magnet material.

[0097] In this invention, when R includes R1 and R2, the content of R2 in the neodymium iron boron magnet material is preferably 0.2-0.7 wt%, for example 0.24 wt%, 0.36 wt%, 0.43 wt%, 0.44 wt%, 0.45 wt%, 0.46 wt%, 0.48 wt%, or 0.55 wt%, more preferably 0.25-0.60 wt%; wt% refers to the mass percentage in the neodymium iron boron magnet material.

[0098] In this invention, R2 can be selected from Tb or Dy.

[0099] In this invention, when R2 contains Dy, the content of Dy is preferably 0.2-0.7 wt%, for example 0.55 wt%, more preferably 0.20-0.60 wt%; wt% refers to the mass percentage in the neodymium iron boron magnet material.

[0100] In this invention, when R2 contains Tb, the content of Tb is preferably 0.2-0.7 wt%, for example 0.24 wt%, 0.36 wt%, 0.43 wt%, 0.44 wt%, 0.45 wt%, 0.46 wt%, or 0.48 wt%, more preferably 0.25-0.60 wt%; wt% refers to the mass percentage in the neodymium iron boron magnet material.

[0101] In some preferred embodiments of the present invention, R1 is selected from Nd and Tb, and R2 is selected from Tb or Dy.

[0102] In some preferred embodiments of the present invention, R1 is selected from Nd and Dy, and R2 is selected from Tb.

[0103] In some preferred embodiments of the present invention, when R contains Dy, the content of Dy is preferably less than 1.50 wt%, for example 0.50 wt%, 0.55 wt%, 1.00 wt%, or 1.50 wt%, more preferably 0.50-1.50 wt%; wt% refers to the mass percentage in the neodymium iron boron magnet material.

[0104] In some preferred embodiments of the present invention, when R contains Tb, the content of Tb is preferably less than 1.50 wt%, for example 0.24 wt%, 0.36 wt%, 0.43 wt%, 0.44 wt%, 0.45 wt%, 0.46 wt%, 0.48 wt%, 1.00 wt%, or 1.35 wt%, more preferably 0.20-1.50 wt%; wt% refers to the mass percentage in the NdFeB magnet material.

[0105] In some preferred embodiments of the present invention, in the neodymium iron boron magnet material, Dy ≤ 0.24 wt%; wt% refers to the mass percentage in the neodymium iron boron magnet material.

[0106] In some preferred embodiments of the present invention, the neodymium iron boron magnet material satisfies 0 ≤ RH / R < 0.1, where R is the total mass content of rare earth elements, RH is the total mass content of heavy rare earth elements in the neodymium iron boron magnet material, and RH includes at least one of Tb and Dy.

[0107] Among them, 0 ≤ RH / R < 0.08 can be satisfied, for example, 0.03, 0.04, 0.05 or 0.06.

[0108] In this invention, the grain boundary triangle generally refers to the area where three or more grain boundaries intersect, containing boron-rich phases, rare earth oxides, rare earth carbides, and voids. The area ratio of the grain boundary triangle is calculated as the ratio of its area to the total area of ​​"grains and grain boundaries".

[0109] In some preferred embodiments of the present invention, the area ratio of the grain boundary triangle region is ≤3.00%, for example, ≤2.80%, or even 2.23%, 2.25%, 2.33%, 2.37%, 2.38%, 2.39%, 2.41%, 2.42%, 2.45%, 2.54%, 2.56%, 2.61%, 2.63%, 2.64%, or 2.71%.

[0110] In this invention, the two grain boundaries of the neodymium iron boron magnet material, except for the chemical composition: R w Fe 100-w-x-y- z Co x Cu y Ga z In addition to the new phase, it generally includes two impurity phases: rare earth oxides and rare earth carbides.

[0111] In some preferred embodiments of the present invention, the chemical composition is R. w Fe 100-w-x-y-z Co x Cu y Ga z In the phase, w is 55.0-63.0%, for example 55.25%, 55.95%, 56.42%, 56.62%, 56.97%, 57.34%, 57.73%, 58.21%, 58.31%, 58.51%, 58.57%, 58.67%, 58.68%, 58.71%, 62.83%, where percentage refers to the atomic percentage in the phase.

[0112] In some preferred embodiments of the present invention, the chemical composition is R. w Fe 100-w-x-y-z Co x Cu y Ga z In the phase, x is 0.30-1.10%, for example 0.35%, 0.36%, 0.39%, 0.42%, 0.44%, 0.46%, 0.48%, 0.49%, 0.54%, 0.59%, 0.61%, 0.62%, 0.81%, 1.08%, where percentage refers to the atomic percentage in the phase.

[0113] In some preferred embodiments of the present invention, the chemical composition is R. w Fe 100-w-x-y-z Co x Cu y Ga zIn the phase, y is 0.35-0.61%, for example 0.37%, 0.41%, 0.42%, 0.44%, 0.45%, 0.46%, 0.47%, 0.51%, 0.55%, or 0.61%, where the percentage refers to the atomic percentage in the phase.

[0114] In some preferred embodiments of the present invention, the chemical composition is R. w Fe 100-w-x-y-z Co x Cu y Ga z In the phase, z is 0.2-0.36%, for example 0.26%, 0.30%, 0.31%, 0.32%, 0.33%, 0.34%, 0.35% or 0.36%, where percentage refers to the atomic percentage in the phase.

[0115] In some preferred embodiments of the present invention, the chemical composition is R. w Fe 100-w-x-y-z Co x Cu y Ga z The specific phase is R 55.25 Fe 43.5 Co 0.44 Cu 0.46 Ga 0.35 R 58.71 Fe 40.08 Co 0.42 Cu 0.47 Ga 0.32 R 62.83 Fe 35.82 Co 0.49 Cu 0.55 Ga 0.31 R 56.62 Fe 42.2 Co 0.39 Cu 0.45 Ga 0.34 R 56.42 Fe 42.55 Co 0.36 Cu 0.37 Ga 0.30 R 57.34 Fe 41.29 Co 0.46 Cu 0.61 Ga 0.36 R 55.95 Fe 42.85 Co 0.46 Cu 0.42 Ga 0.32 R 57.73 Fe 40.98 Co 0.54Cu 0.42 Ga 0.33 R 58.21 Fe 40.69 Co 0.35 Cu 0.44 Ga 0.31 R 56.97 Fe 41.78 Co 0.48 Cu 0.51 Ga 0.26 R 58.51 Fe 40.14 Co 0.59 Cu 0.45 Ga 0.31 R 58.67 Fe 40.00 Co 0.62 Cu 0.41 Ga 0.30 R 58.31 Fe 40.30 Co 0.61 Cu 0.45 Ga 0.33 R 58.57 Fe 39.84 Co 0.81 Cu 0.46 Ga 0.32 or R 58.68 Fe 39.46 Co 1.08 Cu 0.44 Ga 0.34 .

[0116] In this invention, the chemical composition is R w Fe 100-w-x-y-z Co x Cu y Ga z The area of ​​the phase in the two grain boundaries is preferably 0.2-0.9% of the total area of ​​the two grain boundaries, for example, 0.36%, 0.41%, 0.45%, 0.52%, 0.59%, 0.62%, 0.67%, 0.69%, 0.71%, 0.74%, 0.76%, 0.78%, or 0.82%, more preferably 0.3-0.9%.

[0117] In this invention, the Cu content is preferably 0.20-0.35 wt%, for example 0.20 wt%, 0.22 wt%, 0.25 wt%, 0.26 wt%, 0.27 wt%, 0.28 wt%, 0.29 wt%, 0.30 wt%, 0.31 wt%, or 0.34 wt%, more preferably 0.25-0.35 wt%; wt% refers to the mass percentage in the neodymium iron boron magnet material.

[0118] In this invention, the content of Ga is preferably 0.10-0.22 wt%, for example 0.11 wt%, 0.18 wt%, 0.19 wt%, 0.20 wt%, or 0.21 wt%, more preferably 0.15-0.20 wt%; wt% refers to the mass percentage in the neodymium iron boron magnet material.

[0119] In this invention, the content of Al is preferably below 0.08 wt%, more preferably 0.03-0.07 wt%, for example 0.03 wt%, 0.04 wt%, 0.05 wt%, or 0.06 wt%; wt% refers to the mass percentage in the neodymium iron boron magnet material.

[0120] In this invention, the content of B is preferably 0.97-1.05 wt%, for example 0.99 wt%, 1.00 wt%, or 1.01 wt%, more preferably 0.98-1.02 wt%; wt% refers to the mass percentage in the neodymium iron boron magnet material.

[0121] In this invention, the content of Co is preferably 0.30-2.0 wt%, for example 0.38 wt%, 0.55 wt%, 0.58 wt%, 0.60 wt%, 0.61 wt%, 0.62 wt%, 0.64 wt%, 0.85 wt%, 1.00 wt%, 1.50 wt%, and 2.00 wt%; wt% refers to the mass percentage in the NdFeB magnet material.

[0122] In this invention, M can be selected from Ti.

[0123] In this invention, the content of M can be 0.15-0.25 wt%, for example 0.18 wt%, 0.19 wt%, 0.20 wt%, or 0.21 wt%.

[0124] In some preferred embodiments of the present invention, the neodymium iron boron magnet material comprises the following components by weight percentage:

[0125] R: 29.5-31.5 wt%, wherein R is a rare earth element, including Nd and Tb, and optionally, also including Dy; wherein the Nd content is not less than 27.0 wt%;

[0126] Cu: 0.20-0.35 wt%;

[0127] Ga: 0.07-0.22 wt%;

[0128] Al: ≤0.10wt%;

[0129] B: 0.96-1.10 wt%;

[0130] Co: 0.15-2.0 wt%;

[0131] M: 0.10-0.25 wt%, M is selected from at least one of Ti, Zr and Nb;

[0132] The balance consists of Fe and unavoidable impurities;

[0133] The neodymium iron boron magnet material contains Nd2Fe 14 B grains and their shells, adjacent to the Nd2Fe 14 The two grain boundaries and grain boundary triangular regions of B grains, wherein the area of ​​the grain boundary triangular regions is ≤3.00%;

[0134] The two-grain boundary of the neodymium iron boron magnet material includes a chemical composition of R w Fe 100-w-x-y-z Co x Cu y Ga z The phases are defined as follows: w is 55.0-65.0%, x is 0.30-1.20%, y is 0.35-0.65%, z is 0.2-0.4%, and the percentages refer to the atomic percentages in the phases.

[0135] In some preferred embodiments of the present invention, the raw material composition of the neodymium iron boron magnet material comprises the following components, by weight percentage:

[0136] R: 29.5-31.5 wt%, wherein R is a rare earth element, including Nd, Dy and Tb, wherein the Nd content is not less than 27.0 wt%;

[0137] Cu: 0.20-0.35 wt%;

[0138] Ga: 0.07-0.22 wt%;

[0139] Al: ≤0.10wt%;

[0140] B: 0.96-1.10 wt%;

[0141] Co: 0.15-2.0 wt%;

[0142] M: 0.10-0.25 wt%, M is selected from at least one of Ti, Zr and Nb;

[0143] The balance consists of Fe and unavoidable impurities;

[0144] The neodymium iron boron magnet material contains Nd2Fe 14 B grains and their shells, adjacent to the Nd2Fe 14The two grain boundaries and grain boundary triangular regions of B grains, wherein the area of ​​the grain boundary triangular regions is ≤3.00%;

[0145] The two-grain boundary of the neodymium iron boron magnet material includes a chemical composition of R w Fe 100-w-x-y-z Co x Cu y Ga z The phases are defined as follows: w is 55.0-65.0%, x is 0.30-1.20%, y is 0.35-0.65%, z is 0.2-0.4%, and the percentages refer to the atomic percentages in the phases.

[0146] In some preferred embodiments of the present invention, the neodymium iron boron magnet material is formulated as any of the formulations shown in Formulations 16-30 of the following table, by weight percentage:

[0147]

[0148]

[0149] The present invention also provides an application of the neodymium iron boron magnet material as described above in the preparation of magnetic steel.

[0150] The magnet is preferably a 52UH or 54UH magnet.

[0151] The present invention also provides an electronic device comprising the neodymium iron boron magnet material as described above.

[0152] Based on common knowledge in the field, the above-mentioned preferred conditions can be combined arbitrarily to obtain various preferred embodiments of the present invention.

[0153] The reagents and raw materials used in this invention are all commercially available.

[0154] The positive and progressive effects of this invention are as follows: The neodymium iron boron magnet material of this invention, through the combination of various elements in terms of type and content, can reduce the area of ​​the grain boundary triangle region and obtain higher density on the basis of existing neodymium iron boron magnet materials without containing a large amount of heavy rare earth elements. This improves the remanence of the magnet (Br), while generating a new phase in the two-grain grain boundary, improving the fluidity of the grain boundary phase. Correspondingly, the heavy rare earth elements in the two grains are mainly and uniformly distributed in the grain boundary and the main phase shell, thus improving the coercivity (Hcj) of the magnet. Attached Figure Description

[0155] Figure 1 This is a microstructure diagram of the EPMA structure of the NdFeB magnet material in Example 1. Arrow 1 indicates the point where R is contained within the grain boundary between two grains. w Fe 100-w-x-y-z Cox Cu y Ga z The new phase is indicated by arrow 2 at the grain boundary triangle region, and arrow 3 at the Nd2Fe phase. 14 B is the main phase. Detailed Implementation

[0156] The present invention is further illustrated below by way of embodiments, but the invention is not limited to the scope of the embodiments described herein. Experimental methods in the following embodiments that do not specify specific conditions were performed according to conventional methods and conditions, or as selected according to the product instructions.

[0157] 1. The composition and content (wt%) of the neodymium iron boron magnet materials of Examples 1-15 and Comparative Examples 1-10 of the present invention are shown in Table 1 below.

[0158] Table 1

[0159]

[0160]

[0161] Note: " / " indicates that the element is not present. wt% is the mass percentage.

[0162] 2. Preparation method of neodymium iron boron magnet material in Example 1

[0163] (1) Melting and casting process: According to the formula in Table 1, the prepared raw materials except R2 are placed in the crucible of alumina and vacuum melted in a high-frequency vacuum melting furnace at a vacuum of 0.05 Pa and 1520 °C. Argon gas is introduced into a medium-frequency vacuum induction rapid solidification belt casting furnace for casting. The alloy is then rapidly cooled to obtain alloy sheets.

[0164] (2) Hydrogen-crushing powder production process: The hydrogen-crushing furnace containing the rapidly cooled alloy is evacuated at room temperature. Then, hydrogen gas with a purity of 99.9% is introduced into the furnace, maintaining a hydrogen pressure of 90 kPa. After sufficient hydrogen absorption, the temperature is increased while evacuating to fully dehydrogenate the alloy. After cooling, the hydrogen-crushed powder is taken out. The hydrogen absorption temperature is room temperature, and the dehydrogenation temperature is 550℃.

[0165] (3) Airflow milling process: Under nitrogen atmosphere, the powder after hydrogen pulverization is subjected to airflow milling for 3 hours under the condition of 0.6 MPa pressure in the pulverizing chamber to obtain fine powder.

[0166] (4) Molding process: The powder after passing through the airflow membrane is molded in a magnetic field with a strength of 1.5T or higher.

[0167] (5) Sintering process: Each molded body is moved to a sintering furnace for sintering. Sintering is carried out at 1080℃ for 6 hours under a vacuum of less than 0.5 Pa to obtain the sintered body.

[0168] (6) Grain boundary diffusion process: After cleaning the surface of the sintered body, R2 (e.g., an alloy, oxide or fluoride of Tb or Dy, Tb alloy in Example 1) is coated on the surface of the sintered body and diffused at 900°C for 10-15 hours. Then, it is cooled to room temperature and then subjected to low-temperature tempering treatment at 460-560°C for 1-5 hours.

[0169] 3. Composition determination: The neodymium iron boron magnet materials in Examples 1-15 and Comparative Examples 1-10 were analyzed using high-frequency inductively coupled plasma optical emission spectrometry (ICP-OES). The test results are shown in Table 2 below.

[0170] Table 2

[0171] serial number Nd Dy Tb Co Cu Ga Ti B Al Fe Example 1 28.30 1.50 0.48 0.64 0.31 0.20 0.21 0.99 0.06 67.31 Example 2 29.20 1.00 0.46 0.62 0.29 0.19 0.18 1.00 0.04 67.02 Example 3 30.00 0.50 0.45 0.60 0.30 0.18 0.19 0.99 0.05 66.74 Example 4 29.00 1.00 0.36 0.58 0.28 0.18 0.18 0.99 0.04 67.39 Example 5 29.00 1.00 0.24 0.55 0.25 0.20 0.19 1.01 0.03 67.53 Example 6 29.00 1.00 0.44 0.61 0.34 0.21 0.20 0.99 0.05 67.16 Example 7 29.00 1.00 0.43 0.58 0.22 0.18 0.21 0.99 0.06 67.33 Example 8 29.00 1.00 0.48 0.85 0.31 0.18 0.18 0.99 0.04 66.97 Example 9 29.00 1.00 0.46 0.38 0.29 0.19 0.20 1.00 0.05 67.43 Example 10 29.00 1.00 0.45 0.62 0.29 0.11 0.19 0.99 0.05 67.30 Example 11 29.00 0.00 1.35 1.00 0.27 0.19 0.18 1.00 0.05 66.96 Example 12 29.00 0.55 1.00 1.00 0.20 0.19 0.18 0.99 0.04 66.85 Example 13 29.00 1.00 0.44 1.00 0.26 0.18 0.19 0.99 0.05 66.89 Example 14 29.00 1.00 0.45 1.50 0.28 0.18 0.18 0.99 0.06 66.36 Example 15 29.00 1.00 0.45 2.00 0.27 0.19 0.19 1.00 0.05 65.85 Comparative Example 1 29.00 1.00 0.44 / 0.28 0.19 0.21 0.99 0.05 67.84 Comparative Example 2 29.00 1.00 0.43 / 0.27 0.20 0.19 0.99 0.30 67.62 Comparative Example 3 29.00 1.00 0.47 0.61 0.29 / 0.20 0.99 0.05 67.39 Comparative Example 4 29.00 1.00 0.45 0.61 0.09 0.19 0.21 0.99 0.05 67.41 Comparative Example 5 29.00 1.00 0.45 0.65 0.28 0.19 0.20 0.99 0.30 66.94 Comparative Example 6 29.00 1.00 0.43 0.63 0.45 0.20 0.18 1.00 0.05 67.06 Comparative Example 7 29.00 1.00 0.43 0.64 0.27 0.30 0.20 0.99 0.06 67.11 Comparative Example 8 29.00 1.00 0.44 0.68 0.27 0.19 0.40 0.99 0.06 66.97 Comparative Example 9 29.00 1.50 0.05 0.65 0.26 0.19 0.20 0.99 0.05 67.11 Comparative Example 10 29.00 1.00 0.90 0.59 0.28 0.20 0.20 0.99 0.06 66.78

[0172] Example 1

[0173] The neodymium iron boron magnet materials in Examples 1-15 and Comparative Examples 1-10 were subjected to the following tests:

[0174] 1. Magnetic performance testing: The magnetic performance of the sintered magnets was tested using a PFM-14 magnetic performance measuring instrument from Hirs, UK. The test temperature was 20℃. The data of remanence (Br), intrinsic coercivity (Hcj), and squareness (Hk / Hcj) were obtained. The test results are shown in Table 3 below.

[0175] 2. FE-EPMA Analysis: The vertically oriented surfaces of the NdFeB magnet material were polished and analyzed using a field emission electron probe microanalysis (FE-EPMA) system (JEOL, 8530F). The area percentage of the grain boundary triangular region and the presence of new phases were measured using EPMA elemental analysis. The area percentage of the grain boundary triangular region (%) refers to the ratio of the area of ​​the grain boundary triangular region to the total area of ​​grains and grain boundaries, where grain boundaries include both grain boundary triangular regions and two-grain boundaries. The area percentage of new phases within two-grain boundaries (%) refers to the ratio of the area of ​​the new phase within the two-grain boundary to the total area of ​​the two-grain boundary.

[0176] Table 3

[0177]

[0178]

[0179] Note: "×" indicates that the two-grained grain boundary phase does not contain chemical composition R. w Fe 100-w-x-y-zCo x Cu y Ga z The new phase, w, x, y, z refer to the atomic percentages of R (rare earth element), Co, Cu, and Ga in the new phase, respectively.

[0180] As can be seen from the data in Table 3 above, this invention can generate a new phase R in the grain boundary between two grains by controlling the contents of Co, Ga, Cu, rare earth elements, etc. w Fe 100-w-x-y-z Co x Cu y Ga z This new phase improves the fluidity of the grain boundary phase, resulting in a significant increase in the coercivity of the neodymium iron boron magnet material compared to existing technologies, while maintaining high levels of remanence and squareness.

[0181] In the neodymium iron boron magnet materials of Examples 1-15, the heavy rare earth elements in R1 added to the formulation are mainly distributed in Nd2Fe. 14 B grains, R2 are mainly distributed in the shell, two-grain boundaries and grain boundary triangles.

[0182] Example 2

[0183] like Figure 1 The figure shows the EPMA microstructure of the NdFeB magnet material prepared in Example 1. Arrow 1 indicates the point where R0 is contained within the two-grain boundary (light gray area). w Fe 100-w-x-y-z Co x Cu y Ga z The new phase is indicated by arrow 2 at the grain boundary triangle (silver-white area), and arrow 3 at the Nd2Fe phase. 14 B main phase (dark 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 conventional magnetic materials (the area of ​​the grain boundary triangular region in conventional magnetic materials is generally between 3-4%).

Claims

1. A neodymium-iron-boron magnet material, characterized in that, comprises the following components in percentage by weight: R: 28.0-32.0 wt%, the R being rare earth elements, the R comprising Nd, the R further comprising at least one of Tb and Dy, wherein the content of Nd is not less than 27.0 wt%; Cu: 0.16-0.40 wt%; Ga: 0.07-0.24 wt%; Al: ≤0.10 wt%; B: 0.96-1.10 wt%; Co: 0.30-2.0 wt%; M: 0.10-0.25 wt%, M being at least one selected from Ti, Zr and Nb; the balance being Fe and inevitable impurities; The neodymium iron boron magnet material contains Nd2Fe 14 B grains and their shells, adjacent to the Nd2Fe 14 The two-grain boundary and grain boundary triangular region of B grains; the area of ​​the grain boundary triangular region is ≤3.00%; The two-particle grain boundary of the neodymium-iron-boron magnet material includes a phase with a chemical composition of R w Fe 100-w-x-y-z Co x Cu y Ga z , wherein w is 55.0-65.0%, x is 0.30-1.20%, y is 0.35-0.65%, and z is 0.2-0.4%, the percentages being atomic percentages in the phase.

2. The neodymium-iron-boron magnet material as claimed in claim 1, characterized in that the neodymium-iron-boron magnet material satisfying one or more of the following conditions: (a) the area ratio of the grain boundary triangular region being ≤2.80%; (b) the w being 55.0-63.0%, the percentage being atomic percentage in the phase; (c) the x being 0.30-1.10%, the percentage being atomic percentage in the phase; (d) the y being 0.35-0.61%, the percentage being atomic percentage in the phase; (e) the z being 0.2-0.36%, the percentage being atomic percentage in the phase; and, (f) the chemical composition of R w Fe 100-w-x-y-z Co x Cu y Ga z the area of the phase of R in the two-particle grain boundary is 0.2-0.9% of the total area of the two-particle grain boundary.

3. The neodymium-iron-boron magnet material of claim 1, wherein, the neodymium-iron-boron magnet material satisfying one or more of the following conditions: (g) the R comprising R1 and R2; the R1 comprising Nd, the R1 further comprising at least one of Tb and Dy, wherein the content of Nd is not less than 27.0 wt%; the R2 comprising Tb and / or Dy, the content of the R2 being 0.1-0.8 wt%; The heavy rare earth elements in R1 are mainly distributed in Nd2Fe 14 B grains, and R2 is mainly distributed in the shell layer, the grain boundaries of the two grains, and the grain boundary triangular regions. (h) in the neodymium-iron-boron magnet material, Dy ≤0.24 wt%, wt% being mass percentage in the neodymium-iron-boron magnet material; and, (i) in the neodymium-iron-boron magnet material, 0≤RH / R<0.1, wherein R is the total mass content of rare earth elements, RH is the total mass content of heavy rare earth elements in the neodymium-iron-boron magnet material, RH comprising at least one of Tb and Dy.

4. The neodymium-iron-boron magnet material as claimed in claim 3, characterized in that the neodymium-iron-boron magnet material satisfying one or more of the following conditions: (j) the content of the R being 29.5-31.5 wt%; wt% being mass percentage in the neodymium-iron-boron magnet material; (k) in the neodymium-iron-boron magnet material, the content of the Nd being 27.5-30.0 wt%; wt% being mass percentage in the neodymium-iron-boron magnet material; (l) when the R comprises R1 and R2, the content of R1 in the neodymium-iron-boron magnet material being 29.5-31.5 wt%, wt% being mass percentage in the neodymium-iron-boron magnet material; and, (m) when the R comprises R1 and R2, the content of R2 in the neodymium-iron-boron magnet material being 0.2-0.7 wt%, wt% being mass percentage in the neodymium-iron-boron magnet material.

5. The neodymium-iron-boron magnet material according to any one of claims 1 to 4, characterized in that the neodymium-iron-boron magnet material satisfying one or more of the following conditions: (n) the content of the Cu being 0.20-0.35 wt%, wt% being mass percentage in the neodymium-iron-boron magnet material; (o) the content of Al is 0.08wt% or less, wt% refers to the mass percentage in the Nd-Fe-B magnet material; and, (p) the content of B is 0.97-1.05wt%, wt% refers to the mass percentage in the Nd-Fe-B magnet material.

6. A method of producing a neodymium-iron-boron magnet material, characterized by, The Nd-Fe-B magnet material is prepared by a diffusion method using a raw material composition of the Nd-Fe-B magnet material; wherein: (1) the raw material composition of the Nd-Fe-B magnet material comprises the following components in terms of weight percentage: R: 28.0-32.0wt%, the R is a rare earth element, R includes R1 and R2; the R1 is a rare earth element added during smelting, the R1 includes Nd, the R1 also includes at least one of Tb and Dy, wherein the content of Nd is not less than 27.0wt%; the R2 is a rare earth element added during grain boundary diffusion, the R2 includes Tb and / or Dy, the content of R2 is 0.1-0.8wt%; Cu: 0.16-0.40wt%; Ga: 0.07-0.24wt%; Al: ≤0.10wt%; B: 0.96-1.10wt%; Co: 0.30-2.0wt%; M: 0.10-0.25wt%, M is selected from at least one of Ti, Zr and Nb; the balance is Fe and inevitable impurities; (2) the elements in R1 are added in the smelting step, and the elements in R2 are added in the grain boundary diffusion step.

7. The method of producing a neodymium-iron-boron magnet material according to claim 6, characterized in that, The preparation method of the Nd-Fe-B magnet material satisfies one or more of the following conditions: (r) the content of R is 29.5-31.5wt%, wt% refers to the mass percentage in the raw material composition of the Nd-Fe-B magnet material; (s) in the raw material composition of the Nd-Fe-B magnet material, the content of Nd is 27.5-30.0wt%, wt% refers to the mass percentage in the raw material composition of the Nd-Fe-B magnet material; (t) in the raw material composition of the Nd-Fe-B magnet material, Dy≤0.24 wt%, wt% refers to the mass percentage in the raw material composition of the Nd-Fe-B magnet material; (u) the content of R1 in the raw material composition of the Nd-Fe-B magnet material is 29.5-31.5wt%, wt% refers to the mass percentage in the raw material composition of the Nd-Fe-B magnet material; (v) the content of R2 in the raw material composition of the Nd-Fe-B magnet material is 0.2-0.7wt%, wt% refers to the mass percentage in the raw material composition of the Nd-Fe-B magnet material; (w) when the R1 contains Dy, the content of Dy is 1.5wt% or less but not 0, wt% refers to the mass percentage in the raw material composition of the Nd-Fe-B magnet material; (x) when the R1 contains Tb, the content of Tb is 1.5wt% or less but not 0, wt% refers to the mass percentage in the raw material composition of the Nd-Fe-B magnet material; (y) when Dy is contained in said R2, the content of said Dy is 0.2-0.7wt%, wt% means mass percentage in the raw material composition of said neodymium-iron-boron magnet material; (z) when Tb is contained in said R2, the content of said Tb is 0.2-0.7wt%, wt% means mass percentage in the raw material composition of said neodymium-iron-boron magnet material; (aa) said R1 is selected from Nd and Tb, and said R2 is selected from Tb or Dy; or, said R1 is selected from Nd and Dy, and said R2 is selected from Tb; (ab) the content of said Cu is 0.20-0.35wt%, wt% means mass percentage in the raw material composition of said neodymium-iron-boron magnet material; (ac) the content of said Al is 0.08wt% or less, wt% means mass percentage in the raw material composition of said neodymium-iron-boron magnet material; and, (ad) the content of said B is 0.97-1.05wt%, wt% means mass percentage in the raw material composition of said neodymium-iron-boron magnet material.

8. The method of producing a neodymium-iron-boron magnet material according to claim 6 or 7, characterized in that, The preparation method comprises the following steps: melting, powdering, molding and sintering the elements in the raw material composition of said neodymium-iron-boron magnet material except R2 to obtain a sintered body, and then performing grain boundary diffusion on said sintered body and a mixture of said R2 to obtain said neodymium-iron-boron magnet material.

9. The method of producing a neodymium-iron-boron magnet material according to claim 8, characterized in that, The preparation method of said neodymium-iron-boron magnet material satisfies one or more of the following conditions: (ae) the temperature of said melting is 1400-1600℃; (af) the temperature of said sintering is 1000-1200℃; and, (ag) the time of said sintering is 0.5-10h.

10. A neodymium-iron-boron magnet material, characterized in that, It is prepared by the preparation method of any one of claims 6-9.

11. An electronic device, comprising: It comprises the neodymium-iron-boron magnet material of any one of claims 1-5, 10.

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