RTB magnets and the method of manufacturing them.

Abstract

The invention relates to RTB magnets and a method for producing such magnets. RTB magnets consist of the following components: > 30.0% by mass of R, where R is a rare earth element; 0.16 to 0.6% by mass of Cu; 0.4 to 0.8% by mass of Ti; < 0.2% by mass of Ga; 0.955 to 1.2% by mass of B; and 58 to 69% of Fe; where % by mass is the percentage by mass of the respective component in the total mass of all components. RTB magnets according to the invention have higher remanence, coercive force, perpendicularity and high temperature stability. [Fig.1]

Description

RTB magnet and preparation method thereof Technical Field

[0001] The invention relates to an RTB magnet and a preparation method thereof. Background Art

[0002] Neodymium iron boron permanent magnets, as an important rare earth functional material, possess excellent comprehensive magnetic properties and are widely used in many fields, including the electronics industry and electric vehicles. However, the poor temperature stability of current neodymium iron boron magnets limits their application in high-temperature applications.

[0003] For example, Chinese patent document CN102412044A discloses a neodymium iron boron magnet material comprising the following components by weight: Nd: 23-30%, Dy: 0.5-8%, Ti: 0.2-0.5%, Co: 2.5-4%, Nb: 0.2-3.8%, Cu: 0.05-0.7%, Ga: 0.01-0.9%, and B: 0.6-1.8%. The patent document merely states that the composite addition of Ti, Ga, and Co significantly improves the material's corrosion resistance, while also partially replacing Dy in the material, reducing costs. However, the patent does not further investigate the impact of this addition on the magnet material's performance. The examples disclose a composition comprising, by mass, 28.3% Nb, 3.2% Dy, 0.3% Ti, 2.7% Co, 0.7% Nb, 0.4% Cu, 0.25% Ga, and 1.2% B. This magnet material formula fails to fully utilize the benefits of each element in enhancing the magnetic properties of NdFeB magnets, and fails to produce a magnet material with excellent coercivity, remanence, and high-temperature stability.

[0004] At present, the formula of NdFeB magnet materials in the existing technology needs to be further optimized to obtain magnet materials with better comprehensive magnetic properties.

[0005] Summary of the Invention

[0006] To address the existing drawbacks of NdFeB magnet material formulations, which prevent magnets from achieving high levels of remanence, coercivity, high-temperature stability, and squareness, the present invention provides an RTB magnet and a method for preparing the same. The combination of specific element types and contents in the RTB magnet of the present invention enables the production of a magnet material with high remanence, coercivity, and squareness, as well as excellent high-temperature stability.

[0007] The present invention mainly solves the above technical problems through the following technical solutions.

[0008] The present invention also provides an RTB magnet comprising the following components: R: ≥30.0 ​​wt.%, wherein R is a rare earth element;

[0009] Cu: 0.16~0.6wt.%;

[0010] Ti: 0.38-0.8wt.%;

[0011] Ga: ≤0.2wt.%;

[0012] B: 0.955~1.2wt.%;

[0013] Fe: 58-69%; wt.% is the mass percentage of each component to the total mass of all components.

[0014] In the present invention, the content of R is preferably above 30.5 wt.%, more preferably 30.5-32 wt.%, such as 30.6 wt.% or 32 wt.%.

[0015] In the present invention, the R may generally further include Nd.

[0016] Among them, the Nd content is preferably 29-31wt.%, such as 28.6wt.%, 29.6wt.%, 29.8wt.%, 30wt.%, 30.2wt.%, 30.4wt.%, 30.6wt.% or 31wt.%, where wt.% is the mass percentage of the total mass of each component.

[0017] In the present invention, the R may generally further include Pr and / or RH, and the RH is a heavy rare earth element.

[0018] The Pr content is preferably below 0.3 wt.%.

[0019] The content of RH is preferably below 2 wt.%, for example, 0.2 wt.%, 0.4 wt.%, 0.6 wt.%, 0.8 wt.%, 1 wt.% or 2 wt.%, where wt.% is the mass percentage of the total mass of each component.

[0020] The type of RH preferably includes Tb and / or Dy.

[0021] When R contains Tb, the content of Tb is preferably below 1.4 wt.%, for example, 0.2 wt.%, 0.4 wt.%, 0.5 wt.%, 0.6 wt.%, 0.8 wt.% or 1 wt.%, where wt.% is the mass percentage of the total mass of each component.

[0022] When the R contains Dy, the content of Dy is preferably 0.5-2 wt.%, where wt.% is the mass percentage of the total mass of all components.

[0023] The ratio of the atomic percentage of RH to the atomic percentage of R may be less than 0.1, such as 0.02, 0.04, 0.05, 0.06, 0.07, 0.08 or 0.09, where the atomic percentage refers to the atomic percentage of the total content of each component.

[0024] In the present invention, the Cu content is preferably 0.16-0.45 wt.%, such as 0.16 wt.%, 0.21 wt.%, 0.34 wt.% or 0.45 wt.%, more preferably 0.16-0.35 wt.%.

[0025] In the present invention, the Ti content is preferably 0.4-0.7 wt.%, such as 0.4 wt.%, 0.45 wt.%, 0.55 wt.%, 0.6 wt.% or 0.7 wt.%, and more preferably 0.4-0.5 wt.%.

[0026] In the present invention, the Ga content is preferably 0.01 to 0.19 wt.%, such as 0.01 wt.%, 0.02 wt.%, 0.06 wt.% or 0.19 wt.%, more preferably 0.01 to 0.06 wt.%.

[0027] In the present invention, the content of B is preferably 0.96-1.15 wt.%, for example, 0.96 wt.%, 1 wt.%, 1.04 wt.% or 1.15 wt.%.

[0028] In the present invention, the ratio of the atomic percentage of B to the atomic percentage of R in the RTB magnet may be above 0.35, for example, 0.401, 0.420, 0.436, 0.437, 0.438, 0.455 or 0.503, preferably 0.42-0.51, where the atomic percentage refers to the atomic percentage of the total content of each component.

[0029] In the present invention, the Fe content is preferably 66-68 wt.%, for example, 66.3 wt.%, 66.66 wt.%, 66.68 wt.%, 67.09 wt.%, 67.43 wt.%, 67.5 wt.%, 67.54 wt.%, 67.57 wt.%, 67.58 wt.%, 67.64 wt.%, 67.67 wt.%, 67.68 wt.%, 67.7 wt.%, 67.75 wt.% or 67.8 wt.%.

[0030] In the present invention, the RTB magnet may generally further contain Al.

[0031] The Al content is preferably below 0.18 wt.%, such as 0.02 wt.%, 0.04 wt.%, 0.05 wt.%, 0.06 wt.%, 0.07 wt.% or 0.14 wt.%, preferably 0.02-0.08 wt.%, where wt.% is the mass percentage of the total mass of each component.

[0032] In the present invention, the RTB magnet may generally further contain Co.

[0033] The content of Co may be 0.5-1.5 wt%, for example, 1 wt%, where wt% is the mass percentage of the total mass of each component.

[0034] In the present invention, those skilled in the art will know that unavoidable impurities, such as C and / or O, may be introduced into the RTB magnet during the preparation process.

[0035] The inventors found that the combination of the above-mentioned specific contents of Cu, Ti, Ga and other elements significantly improved the magnetic properties of the RTB magnet, such as coercivity, high temperature stability and squareness. Further analysis found that after the above-mentioned specific formula of the application was prepared into an RTB magnet, a specific area ratio of Ti was formed in the RTB magnet. x Cu y B 1-x-y The presence of this phase can significantly hinder the growth of grains, making the size of the main phase grains in the magnet more uniform, thereby obtaining the RTB magnet with excellent comprehensive magnetic properties of the present invention.

[0036] In the present invention, the RTB magnet preferably also includes Ti x Cu y B 1-x-y Phase, x is 20 to 30, y is 20 to 30, 1-xy is 40 to 60, wherein x, y, 1-xy refer to Ti, Cu, and B in the Ti phase, respectively. x Cu y B 1-x-y The atomic percentage of the Ti phase. x Cu y B 1-x-y Phase is located in the intergranular triangle area, the Ti x Cu y B 1-x-yThe ratio of the area of ​​the phase to the total area of ​​the "neodymium-rich phase and intergranular triangular region" is 1 to 5%. In the present invention, the intergranular triangular region generally refers to the grain boundary phase formed between more than three main phase particles. In the present invention, the Ti x Cu y B 1-x-y The area of ​​the phase or the total area of ​​the “Nd-rich phase and the intergranular triangular region” generally refers to the area occupied by each phase in the cross section of the RTB tested during FE-EPMA testing.

[0037] The value of x is, for example, 21, 22, 23, 24, 25 or 27.

[0038] The value of y is, for example, 21, 22, 23, 24, 25, 26 or 27.

[0039] The value of 1-xy is, for example, 48, 49, 50, 51, 52, 53, 55 or 58.

[0040] Wherein, the Ti x Cu y B 1-x-y The ratio of the area of ​​the phase to the total area of ​​the "Nd-rich phase and intergranular triangular region" is preferably 2.5-4%, for example 2.9%, 3.2%, 3.4%, 3.5%, 3.6%, 3.7% or 3.9%.

[0041] In a specific embodiment of the present invention, the RTB magnet comprises the following components: Nd 29.6wt.%, Tb 1wt.%, Cu 0.21wt.%, Ti 0.45wt.%, B 1wt.%, Ga 0.02wt.%, Al 0.04wt.% and Fe 67.68wt.%, where wt.% is the mass percentage of each component to the total mass of each component; the intergranular triangular region of the RTB magnet contains Ti 23 Cu 25 B 52 phase, the Ti 23 Cu 25 B 52 The ratio of the area of ​​the phase to the total area of ​​the "neodymium-rich phase and intergranular triangular region" is 3.5%.

[0042] In a specific embodiment of the present invention, the RTB magnet comprises the following components: Nd 29.8wt.%, Tb 0.8wt.%, Cu 0.21wt.%, Ti 0.45wt.%, B 1wt.%, Ga 0.02wt.%, Al 0.05wt.% and Fe 67.67wt.%, where wt.% is the mass percentage of each component to the total mass of each component; the intergranular triangular region of the RTB magnet contains Ti23 Cu 24 B 53 phase, the Ti 23 Cu 24 B 53 The ratio of the area of ​​the phase to the total area of ​​the "neodymium-rich phase and intergranular triangular region" is 3.4%.

[0043] In a specific embodiment of the present invention, the RTB magnet comprises the following components: Nd 30wt.%, Tb 0.6wt.%, Cu 0.21wt.%, Ti 0.45wt.%, B 1wt.%, Ga 0.02wt.%, Al 0.04wt.%, and Fe 67.68wt.%, where wt.% is the mass percentage of each component to the total mass of each component; the intergranular triangular region of the RTB magnet contains Ti 22 Cu 26 B 52 phase, the Ti 22 Cu 26 B 52 The ratio of the area of ​​the phase to the total area of ​​the "neodymium-rich phase and intergranular triangular region" is 3.6%.

[0044] In a specific embodiment of the present invention, the RTB magnet comprises the following components: Nd 30.2wt.%, Tb 0.4wt.%, Cu 0.21wt.%, Ti 0.45wt.%, B 1wt.%, Ga 0.02wt.%, Al 0.08wt.% and Fe 67.64wt.%, where wt.% is the mass percentage of each component to the total mass of each component; the intergranular triangular region of the RTB magnet contains Ti 25 Cu 25 B 50 phase, the Ti 25 Cu 25 B 50 The ratio of the area of ​​the phase to the total area of ​​the "neodymium-rich phase and intergranular triangular region" is 3.5%.

[0045] In a specific embodiment of the present invention, the RTB magnet comprises the following components: Nd 30.4wt.%, Tb 0.2wt.%, Cu 0.21wt.%, Ti 0.45wt.%, B 1wt.%, Ga 0.02wt.%, Al 0.02wt.% and Fe 67.7wt.%, where wt.% is the mass percentage of each component to the total mass of each component; the intergranular triangular region of the RTB magnet contains Ti 24 Cu 26 B 50 phase, the Ti 24 Cu 26 B50 The ratio of the area of ​​the phase to the total area of ​​the "neodymium-rich phase and intergranular triangular region" is 3.5%.

[0046] In a specific embodiment of the present invention, the RTB magnet comprises the following components: Nd 30.6wt.%, Cu 0.21wt.%, Ti 0.45wt.%, B 1wt.%, Ga 0.02wt.%, Al 0.05wt.% and Fe 67.67wt.%, where wt.% is the mass percentage of each component to the total mass of each component; the intergranular triangular region of the RTB magnet contains Ti 22 Cu 23 B 55 phase, the Ti 22 Cu 23 B 55 The ratio of the area of ​​the phase to the total area of ​​the "neodymium-rich phase and intergranular triangular region" is 3.2%.

[0047] In a specific embodiment of the present invention, the RTB magnet comprises the following components: Nd 29.6wt.%, Tb 1wt.%, Co 1wt.%, Cu 0.21wt.%, Ti 0.45wt.%, B 1wt.%, Ga 0.02wt.%, Al 0.04wt.% and Fe 66.68wt.%, where wt.% is the mass percentage of each component to the total mass of each component; the intergranular triangular region of the RTB magnet contains Ti 26 Cu 25 B 49 phase, the Ti 26 Cu 25 B 49 The ratio of the area of ​​the phase to the total area of ​​the "neodymium-rich phase and intergranular triangular region" is 3.6%.

[0048] In a specific embodiment of the present invention, the RTB magnet comprises the following components: Nd 30.6wt.%, Co 1wt.%, Cu 0.21wt.%, Ti 0.45wt.%, B 1wt.%, Ga 0.02wt.%, Al 0.06wt.% and Fe 66.66wt.%, where wt.% is the mass percentage of each component to the total mass of each component; the intergranular triangular region of the RTB magnet contains Ti 24 Cu 25 B 51 phase, the Ti 24 Cu 25 B 51 The ratio of the area of ​​the phase to the total area of ​​the "neodymium-rich phase and intergranular triangular region" is 3.2%.

[0049] In a specific embodiment of the present invention, the RTB magnet comprises the following components: Nd 29.6wt.%, Tb 1wt.%, Cu 0.21wt.%, Ti 0.45wt.%, B 1wt.%, Ga 0.19wt.%, Al 0.05wt.% and Fe 67.5wt.%, where wt.% is the mass percentage of each component to the total mass of each component; the intergranular triangular region of the RTB magnet contains Ti 23 Cu 25 B 52 phase, the Ti 23 Cu 25 B 52 The ratio of the area of ​​the phase to the total area of ​​the "neodymium-rich phase and intergranular triangular region" is 2.9%.

[0050] In a specific embodiment of the present invention, the RTB magnet comprises the following components: Nd 29.6wt.%, Tb 1wt.%, Cu 0.21wt.%, Ti 0.55wt.%, B 1wt.%, Ga 0.02wt.%, Al 0.05wt.% and Fe 67.57wt.%, where wt.% is the mass percentage of each component to the total mass of each component; the intergranular triangular region of the RTB magnet contains Ti 27 Cu 25 B 48 phase, the Ti 27 Cu 25 B 48 The ratio of the area of ​​the phase to the total area of ​​the "neodymium-rich phase and intergranular triangular region" is 3.5%.

[0051] In a specific embodiment of the present invention, the RTB magnet comprises the following components: Nd 29.6wt.%, Tb 1wt.%, Cu 0.21wt.%, Ti 0.7wt.%, B 1wt.%, Ga 0.02wt.%, Al 0.04wt.% and Fe 67.43wt.%, where wt.% is the mass percentage of each component to the total mass of each component; the intergranular triangular region of the RTB magnet contains Ti 25 Cu 25 B 50 phase, the Ti 25 Cu 25 B 50 The ratio of the area of ​​the phase to the total area of ​​the "neodymium-rich phase and intergranular triangular region" is 3.4%.

[0052] In a specific embodiment of the present invention, the RTB magnet comprises the following components: Nd 29.6wt.%, Tb 1wt.%, Cu 0.34wt.%, Ti 0.45wt.%, B 1wt.%, Ga 0.02wt.%, Al 0.05wt.% and Fe 67.54wt.%, where wt.% is the mass percentage of each component to the total mass of each component; the intergranular triangular region of the RTB magnet contains Ti 24 Cu 24 B 52 phase, the Ti 24 Cu 24 B 52 The ratio of the area of ​​the phase to the total area of ​​the "neodymium-rich phase and intergranular triangular region" is 3.7%.

[0053] In a specific embodiment of the present invention, the RTB magnet comprises the following components: Nd 29.6wt.%, Tb 1wt.%, Cu 0.21wt.%, Ti 0.45wt.%, B 1.04wt.%, Ga 0.02wt.%, Al 0.04wt.% and Fe 67.64wt.%, where wt.% is the mass percentage of each component to the total mass of each component; the intergranular triangular region of the RTB magnet contains Ti 21 Cu 21 B 58 phase, the Ti 21 Cu 21 B 58 The ratio of the area of ​​the phase to the total area of ​​the "neodymium-rich phase and intergranular triangular region" is 3.6%.

[0054] In a specific embodiment of the present invention, the RTB magnet comprises the following components: Nd 31wt.%, Tb 1wt.%, Cu 0.21wt.%, Ti 0.45wt.%, B 0.96wt.%, Ga 0.02wt.%, Al 0.06wt.% and Fe 66.3wt.%, where wt.% is the mass percentage of each component to the total mass of each component; the intergranular triangular region of the RTB magnet contains Ti 25 Cu 23 B 52 phase, the Ti 25 Cu 23 B 52 The ratio of the area of ​​the phase to the total area of ​​the "neodymium-rich phase and intergranular triangular region" is 3.9%.

[0055] In a specific embodiment of the present invention, the RTB magnet comprises the following components: Nd 29.8wt.%, Tb 0.8wt.%, Cu 0.21wt.%, Ti 0.45wt.%, B 1wt.%, Ga 0.02wt.%, Al 0.14wt.% and Fe 67.58wt.%, where wt.% is the mass percentage of each component to the total mass of each component; the intergranular triangular region of the RTB magnet contains Ti 24 Cu 26 B 50 phase, the Ti 24 Cu 26 B 50 The ratio of the area of ​​the phase to the total area of ​​the "neodymium-rich phase and intergranular triangular region" is 3.4%.

[0056] In a specific embodiment of the present invention, the RTB magnet comprises the following components: Nd 29.6wt.%, Tb 1wt.%, Cu 0.45wt.%, Ti 0.6wt.%, B 1.15wt.%, Ga 0.06wt.%, Al 0.05wt.% and Fe 67.09wt.%, where wt.% is the mass percentage of each component to the total mass of each component; the intergranular triangular region of the RTB magnet contains Ti 27 Cu 23 B 50 phase, the Ti 27 Cu 23 B 50 The ratio of the area of ​​the phase to the total area of ​​the "neodymium-rich phase and intergranular triangular region" is 3.5%.

[0057] In a specific embodiment of the present invention, the RTB magnet comprises the following components: Nd 29.6wt.%, Tb 1wt.%, Cu 0.16wt.%, Ti 0.4wt.%, B 0.96wt.%, Ga 0.01wt.%, Al 0.07wt.% and Fe 67.8wt.%, where wt.% is the mass percentage of each component to the total mass of each component; the intergranular triangular region of the RTB magnet contains Ti 24 Cu 25 B 51 phase, the Ti 24 Cu 25 B 51 The ratio of the area of ​​the phase to the total area of ​​the "neodymium-rich phase and intergranular triangular region" is 3.4%.

[0058] In a specific embodiment of the present invention, the RTB magnet comprises the following components: Nd 29.6wt.%, Tb 1wt.%, Cu 0.21wt.%, Ti 0.4wt.%, B 1wt.%, Al 0.04wt.% and Fe 67.75wt.%, where wt.% is the mass percentage of each component to the total mass of each component; the intergranular triangular region of the RTB magnet contains Ti 26 Cu 26 B 48 phase, the Ti 26 Cu 26 B 48 The ratio of the area of ​​the phase to the total area of ​​the "neodymium-rich phase and intergranular triangular region" is 3.5%.

[0059] In a specific embodiment of the present invention, the RTB magnet comprises the following components: Nd 30.1wt.%, Dy 0.5wt.%, Cu 0.21wt.%, Ti 0.45wt.%, B 1wt.%, Ga 0.02wt.%, Al 0.05wt.% and Fe 67.67wt.%, where wt.% is the mass percentage of each component to the total mass of each component; the intergranular triangular region of the RTB magnet contains Ti 25 Cu 27 B 48 phase, the Ti 25 Cu 27 B 48 The ratio of the area of ​​the phase to the total area of ​​the "neodymium-rich phase and intergranular triangular region" is 3.4%.

[0060] In a specific embodiment of the present invention, the RTB magnet comprises the following components: Nd 28.6wt.%, Dy 2wt.%, Cu 0.21wt.%, Ti 0.5wt.%, B 1wt.%, Ga 0.02wt.%, Al 0.03wt.% and Fe 67.64wt.%, where wt.% is the mass percentage of each component to the total mass of each component; the intergranular triangular region of the RTB magnet contains Ti 27 Cu 28 B 45 phase, the Ti 27 Cu 28 B 45 The ratio of the area of ​​the phase to the total area of ​​the "neodymium-rich phase and intergranular triangular region" is 3.5%.

[0061] In a specific embodiment of the present invention, the RTB magnet comprises the following components: Nd 29.6wt.%, Tb 0.5wt.%, Dy 0.5wt.%, Cu 0.21wt.%, Ti 0.48wt.%, B 1wt.%, Ga 0.02wt.%, Al 0.06wt.%, Fe 67.63wt.%, where wt.% is the mass percentage of each component to the total mass of each component; the intergranular triangular region of the RTB magnet contains Ti 24 Cu 24 B 52 phase, the Ti 24 Cu 24 B 52 The ratio of the area of ​​the phase to the total area of ​​the "neodymium-rich phase and intergranular triangular region" is 3.5%.

[0062] The present invention also provides a method for preparing the RTB magnet, which comprises the following steps: subjecting a raw material mixture of each component in the RTB magnet to sintering treatment and aging treatment to obtain the RTB magnet.

[0063] In the present invention, the temperature of the sintering treatment can be a conventional temperature in the art, preferably 1000-1100°C, for example 1080°C.

[0064] In the present invention, the sintering process is preferably carried out under vacuum conditions. -3 Pa vacuum conditions.

[0065] In the present invention, the sintering treatment time can be conventional in the art, generally 4 to 8 hours, for example 6 hours.

[0066] In the present invention, the aging treatment may adopt conventional aging processes in the art, generally including primary aging treatment and secondary aging treatment.

[0067] The temperature of the primary aging treatment can be conventional in the art, preferably 860-920°C, such as 880°C or 900°C.

[0068] The time of the primary aging treatment can be conventional in the art, preferably 2.5 to 4 hours, for example 3 hours.

[0069] The temperature of the secondary aging treatment can be conventional in the art, preferably 460-530°C, such as 500°C, 510°C or 520°C.

[0070] The secondary aging treatment may last for 2.5 to 4 hours, for example, 3 hours.

[0071] In the present invention, when the RTB magnet further contains heavy rare earth elements, the aging treatment generally includes grain boundary diffusion.

[0072] The grain boundary diffusion may be a conventional process in the art, and generally involves the grain boundary diffusion of heavy rare earth elements.

[0073] The temperature of the grain boundary diffusion may be 800-900° C., for example, 850° C. The time of the grain boundary diffusion may be 5-10 hours, for example, 8 hours.

[0074] The addition of heavy rare earth elements to the RTB magnets can be based on conventional methods in the art, typically adding 0-80% of the heavy rare earth elements during smelting and the remainder during smelting, for example, 25%, 30%, 40%, 50%, or 67%. The heavy rare earth element added during smelting is, for example, Tb.

[0075] For example, when the heavy rare earth element in the RTB magnet is Tb and Tb is greater than 0.5wt.%, 40-67% of Tb is added during smelting, and the remainder is added during grain boundary diffusion. For example, when the heavy rare earth elements in the RTB magnet are Tb and Dy, the Tb is added during smelting, and the Dy is added during grain boundary diffusion. For example, when the heavy rare earth element in the RTB magnet is Tb and Tb is less than or equal to 0.5wt.% or when the heavy rare earth element in the RTB magnet is Dy, the heavy rare earth element in the RTB magnet is added during grain boundary diffusion.

[0076] The grain boundary diffusion is generally followed by a secondary aging treatment. The temperature and time ranges of the secondary aging treatment are as described above. The temperature is, for example, 500° C. and the time is, for example, 3 hours.

[0077] In the present invention, those skilled in the art know that, before the sintering treatment, the conventional smelting, casting, hydrogen crushing, fine crushing and magnetic field forming processes in the art are generally included.

[0078] The vacuum degree of the smelting is, for example, 5×10 -2 Pa.

[0079] The smelting temperature is, for example, below 1550°C.

[0080] The smelting is generally carried out in a high-frequency vacuum induction melting furnace.

[0081] The casting process adopts a rapid solidification sheet casting method, for example.

[0082] The casting temperature may be 1390-1460°C, for example, 1400°C, 1420°C or 1430°C.

[0083] The thickness of the alloy sheet obtained after the casting may be 0.25 to 0.40 mm, for example, 0.29 mm.

[0084] The hydrogen crushing process generally includes hydrogen absorption, dehydrogenation and cooling in sequence.

[0085] The hydrogen absorption can be performed under a hydrogen pressure of 0.085 MPa.

[0086] The dehydrogenation can be carried out under vacuum while heating. The dehydrogenation temperature can be 480-520°C, for example 500°C.

[0087] Wherein, the fine grinding can be performed by jet mill grinding.

[0088] The particle size of the powder after the fine grinding may be 4.1 to 4.4 μm, for example, 4.1 μm, 4.2 μm or 4.3 μm.

[0089] The gas atmosphere during the fine grinding may be an oxidizing gas with an oxidizing gas content of less than 1000 ppm, where the oxidizing gas content refers to the content of oxygen or water.

[0090] The pressure during the fine grinding is, for example, 0.68 MPa.

[0091] After the fine grinding, a lubricant, such as zinc stearate, is generally added.

[0092] The amount of the lubricant added may be 0.05-0.15% of the mass of the powder obtained after the fine grinding, for example 0.12%.

[0093] The magnetic field forming is performed under a magnetic field strength of 1.8 T or higher and a nitrogen atmosphere, for example, a magnetic field strength of 1.8 to 2.5 T.

[0094] The present invention also provides an RTB magnet, which is prepared by the above-mentioned preparation method.

[0095] On the basis of conforming to the common sense in this field, the above-mentioned preferred conditions can be arbitrarily combined to obtain the preferred embodiments of the present invention.

[0096] The reagents and raw materials used in the present invention are commercially available.

[0097] The positive progress of the present invention is that the RTB magnet of the present invention optimizes the coordination relationship between the elements by coordinating the specific contents of Cu, Ti, Ga and other elements, thereby optimizing the microstructure during the preparation of the RTB magnet, thereby obtaining a magnet material with relatively high magnetic properties such as coercivity, high-temperature stability and squareness. BRIEF DESCRIPTION OF THE DRAWINGS

[0098] Figure 1 shows the Ti 23 Cu 25 B 52 The SEM spectrum of the RTB magnet with phase. The arrow a in Figure 1 points to the Ti in the intercrystalline triangle area. 23 Cu 25 B 52 Mutually. DETAILED DESCRIPTION

[0099] The present invention is further illustrated by way of examples below, but the present invention is not limited to the scope of the examples. Experimental methods in the following examples where specific conditions are not specified were performed according to conventional methods and conditions, or selected according to the product specifications.

[0100] Example 1

[0101] Prepare the raw materials according to the ingredients of the RTB magnet in Table 1 and follow the preparation steps below:

[0102] (1) Melting process: The prepared raw materials (0.4 wt.% of Tb in Table 1 is added during melting, and the remaining 0.6 wt.% is added in the grain boundary diffusion described below) are placed in a vacuum chamber with a degree of vacuum of 5×10 -2 Pa high frequency vacuum induction melting furnace, and melted into molten liquid at a temperature below 1550 ° C.

[0103] (2) Casting process: The alloy casting sheet with a thickness of 0.29 mm was obtained by using the rapid solidification casting method, and the casting temperature was 1420°C.

[0104] (3) Hydrogen crushing process: After hydrogen absorption, dehydrogenation, and cooling. Hydrogen absorption is carried out under the condition of hydrogen pressure of 0.085MPa. Dehydrogenation is carried out under the condition of vacuum and heating, and the dehydrogenation temperature is 500℃.

[0105] (4) Fine Pulverization: The powder was jet milled in an atmosphere containing an oxidizing gas content of less than 100 ppm, where the oxidizing gas refers to oxygen or moisture, to a particle size of 4.2 μm. The pressure in the jet milling chamber was 0.68 MPa. After pulverization, zinc stearate was added as a lubricant at a level of 0.12% by weight of the mixed powder.

[0106] (6) Magnetic field forming process: The magnetic field forming method is adopted, and the forming is carried out under the protection of a nitrogen atmosphere and a magnetic field strength of 1.8 to 2.5 T.

[0107] (7) Sintering process: at 5×10 -3Sintering and cooling under vacuum conditions of Pa. Sintering at 1080℃ for 6h; before cooling, Ar gas can be introduced to make the pressure reach 0.05MPa.

[0108] (8) Aging treatment: the primary aging temperature is 900℃ and the time is 3h; the secondary aging temperature is 510℃ and the time is 3h.

[0109] (9) Grain boundary diffusion treatment: The remaining 0.6 wt.% Tb is diffused into the magnet material through grain boundary diffusion at a temperature of 850°C for 8 hours. After the grain boundary diffusion is completed, a second secondary aging treatment is performed at a temperature of 500°C for 3 hours.

[0110] The RTB magnets of Examples 2-21 and Comparative Examples 1-5 were prepared using the raw materials formulated in Table 1 and the preparation process of Example 1. In Examples 2, 3, 7, 9-18 and Comparative Examples 1-4, 0.4 wt% of Tb was added during smelting, with the remaining Tb incorporating into the RTB magnet via grain boundary diffusion. The heavy rare earth elements in Examples 4, 5, 19, and 20 were all added via grain boundary diffusion. In Example 21, Tb was added during smelting, and Dy was added via grain boundary diffusion.

[0111] Effect Example 1

[0112] 1. Composition determination: The RTB magnets in Examples 1 to 21 and Comparative Examples 1 to 5 were measured using a high-frequency inductively coupled plasma optical emission spectrometer (ICP-OES). The test results are shown in Table 1 below.

[0113] Table 1 Formulations of RTB magnets in Examples 1 to 21 and Comparative Examples 1 to 4 (wt.%)

[0114]

[0115]

[0116] Note: / indicates the absence of the element. C, O, and Mn are inevitably introduced into the final RTB magnet during the production process; these impurities are not included in the denominator of the percentages calculated in the Examples and Comparative Examples. Furthermore, Example 15 in Table 1 contains 0.14 wt.% Al. Common sense suggests that some of this Al content is due to impurities introduced during the production process. The Al content below 0.08 wt.% in the remaining Examples and Comparative Examples was also introduced during the production process.

[0117] 2. Magnetic performance test

[0118] The RTB magnets in Examples 1 to 21 and Comparative Examples 1 to 5 were tested using a PFM pulsed BH demagnetization curve tester to obtain data on remanence (Br), intrinsic coercivity (Hcj), maximum magnetic energy product (BHmax), and squareness (Hk / Hcj). The test results are shown in Table 2 below.

[0119] Table 2

[0120]

[0121]

[0122] 3. Microstructure testing

[0123] FE-EPMA Analysis: The perpendicularly oriented surfaces of the RTB magnets in Examples 1-21 and Comparative Examples 1-5 were polished and analyzed using a field emission electron probe microanalyzer (FE-EPMA) (JEOL Ltd., 8530F). FE-EPMA surface scanning was first used to determine the distribution of elements such as Cu, Ti, and B in the RTB magnets. FE-EPMA single-point quantitative analysis was then used to determine the content of each element in the Ti-Cu-B phase. The testing conditions were an accelerating voltage of 15 kV and a probe beam current of 50 nA.

[0124] Figure 1 shows a SEM image of the RTB magnet from Example 1 obtained through FE-EPMA analysis. The SEM image confirmed the location of the Ti-Cu-B phase, which is located in the intergranular triangular region. The area fraction of the Ti-Cu-B phase was further calculated. The arrow in a of Figure 1 indicates the Ti-Cu-B phase, identified by quantitative analysis at a single point within the intergranular triangular region.

[0125] Through detection and calculation, it can be found that Ti-Cu-B phase is formed in the intergranular triangle region of the RTB magnet in Example 1. The atomic percentage of Ti, Cu and B in the Ti-Cu-B phase is 23:25:52, which is expressed as Ti 23 Cu 25 B 52 Phase. Ti 23 Cu 25 B 52 The ratio of the Ti-Cu-B phase area to the total area of ​​the intergranular triangular region and the Nd-rich phase (referred to as the phase area ratio in Table 3) is 3.5%. The Ti-Cu-B phase area and the total area of ​​the intergranular triangular region and the Nd-rich phase respectively refer to the area occupied by the cross-section of the RTB magnet (the aforementioned perpendicular orientation plane) measured during FE-EPMA analysis.

[0126] The test results of FE-EPMA in the RTB magnets in Examples 1 to 21 and Comparative Examples 1 to 5 are shown in Table 3 below.

[0127] Table 3

[0128]

[0129]

[0130] Although specific embodiments of the present invention have been described above, those skilled in the art will appreciate that these are merely illustrative and that the scope of the present invention is defined by the appended claims. Those skilled in the art may make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, and such changes and modifications are intended to fall within the scope of the present invention.

Claims

1. An R-T-B magnet, characterized in that, It includes the following components: R: ≥30.0 wt.%, where R is a rare earth element; Cu: 0.16 - 0.6 wt.%; Ti: 0.4 - 0.8 wt.%; Ga: ≤0.2 wt.%; B: 0.955 - 1.2 wt.%; Fe: 58 - 69%; wt.% is the mass percentage of each component in the total mass of all components.

2. The R-T-B magnet according to claim 1, characterized in that, The content of R is above 30.5 wt.%, preferably 30.5 - 32 wt.%, such as 30.6 wt.% or 32 wt.%; and / or, R also includes Nd; Among them, the content of Nd is preferably 29 - 31 wt.%, such as 28.6 wt.%, 29.6 wt.%, 29.8 wt.%, 30 wt.%, 30.2 wt.%, 30.4 wt.%, 30.6 wt.% or 31 wt.%, and wt.% is the mass percentage in the total mass of all components; and / or, R also includes Pr and / or RH, where RH is a heavy rare earth element; Among them, the content of Pr is preferably below 0.3 wt.%; Among them, the content of RH is preferably below 2 wt.%, such as 0.2 wt.%, 0.4 wt.%, 0.6 wt.%, 0.8 wt.%, 1 wt.% or 2 wt.%, and wt.% is the mass percentage in the total mass of all components; Among them, the type of RH preferably includes Tb and / or Dy; When R contains Tb, the content of Tb is preferably below 1.4 wt.%, such as 0.2 wt.%, 0.4 wt.%, 0.5 wt.%, 0.6 wt.%, 0.8 wt.% or 1 wt.%, and wt.% is the mass percentage in the total mass of all components; When R contains Dy, the content of Dy is preferably 0.5 - 2 wt.%, and wt.% is the mass percentage in the total mass of all components; The ratio of the atomic percentage content of RH to the atomic percentage content of R is preferably below 0.1, such as 0.02, 0.04, 0.05, 0.06, 0.07, 0.08 or 0.09, and the atomic percentage content refers to the atomic percentage in the total content of all components.

3. The R-T-B magnet according to claim 1, characterized in that, The content of Cu is 0.16 - 0.45 wt.%, such as 0.16 wt.%, 0.21 wt.%, 0.34 wt.% or 0.45 wt.%, and is preferably 0.16 - 0.35 wt.%; and / or, the content of Ti is 0.4 - 0.7 wt.%, such as 0.4 wt.%, 0.45 wt.%, 0.55 wt.%, 0.6 wt.% or 0.7 wt.%, and is preferably 0.4 - 0.5 wt.%; and / or, the content of Ga is 0.01 - 0.19 wt.%, such as 0.01 wt.%, 0.02 wt.%, 0.06 wt.% or 0.19 wt.%, and is preferably 0.01 - 0.06 wt.%; And / or, the content of B is 0.96 to 1.15 wt.%, such as 0.96 wt.%, 1 wt.%, 1.04 wt.%, or 1.15 wt.%. And / or, the ratio of the atomic percentage content of B to the atomic percentage content of R in the R-T-B magnet is above 0.35, such as 0.401, 0.420, 0.436, 0.437, 0.438, 0.455, or 0.503, preferably 0.42 to 0.

51. And / or, the content of Fe is 66 to 68 wt.%, such as 66.3 wt.%, 66.66 wt.%, 66.68 wt.%, 67.09 wt.%, 67.43 wt.%, 67.5 wt.%, 67.54 wt.%, 67.57 wt.%, 67.58 wt.%, 67.64 wt.%, 67.67 wt.%, 67.68 wt.%, 67.7 wt.%, 67.75 wt.%, or 67.8 wt.%.

4. The R-T-B magnet according to claim 1, characterized in that, The R-T-B magnet described above further contains Al. Wherein, the content of Al is preferably below 0.18 wt.%, such as 0.02 wt.%, 0.04 wt.%, 0.05 wt.%, 0.06 wt.%, 0.07 wt.%, or 0.14 wt.%, more preferably 0.02 to 0.08 wt.%, and wt.% is the mass percentage based on the total mass of each component. And / or, the R-T-B magnet described above further contains Co. Wherein, the content of Co is preferably 0.5 to 1.5 wt%, such as 1 wt.%, and wt.% is the mass percentage based on the total mass of each component.

5. The R-T-B magnet according to any one of claims 1 to 4, characterized in that, The described R-T-B magnet further includes Ti x Cu y B 1-x-y phase, where x is 20 to 30, y is 20 to 30, and 1 - x - y is 40 to 60. x, y, and 1 - x - y respectively refer to the atomic percentage ratios of Ti, Cu, and B in the x Cu y B 1-x-y phase; the x Cu y B 1-x-y phase is located in the intergranular triangular region, and the area ratio of the x Cu y B 1-x-y phase to the total area of the "neodymium-rich phase and intergranular triangular region" is 1 to 5%; Wherein, the value of x is, for example, 21, 22, 23, 24, 25, or 27. Wherein, the value of y is, for example, 21, 22, 23, 24, 25, 26, or 27. Wherein, the value of 1 - x - y is, for example, 48, 49, 50, 51, 52, 53, 55, or 58. Among them, the Ti x Cu y B 1-x-y The area ratio of the phase to the total area of the "neodymium-rich phase and intergranular triangular area" is preferably 2.5-4%, such as 2.9%, 3.2%, 3.4%, 3.5%, 3.6%, 3.7% or 3.9%.

6. The R-T-B magnet according to claim 1, characterized in that, The R-T-B magnet comprises the following components: Nd 29.6 wt.%, Tb 1 wt.%, Cu 0.21 wt.%, Ti 0.45 wt.%, B 1 wt.%, Ga 0.02 wt.%, Al 0.04 wt.%, and Fe 67.68 wt.%, where wt.% is the mass percentage of each component in the total mass of all components; the intergranular triangular region of the R-T-B magnet contains Ti 23 Cu 25 B 52 phase, and the area ratio of the Ti 23 Cu 25 B 52 phase to the total area of the "Nd-rich phase and intergranular triangular region" is 3.5%; Alternatively, the R-T-B magnet comprises the following components: Nd 29.8 wt.%, Tb 0.8 wt.%, Cu 0.21 wt.%, Ti 0.45 wt.%, B 1 wt.%, Ga 0.02 wt.%, Al 0.05 wt.%, and Fe 67.67 wt.%, where wt.% is the mass percentage of each component in the total mass of all components; Ti is contained in the intergranular triangular region of the R-T-B magnet 23 Cu 24 B 53 phase, and the area ratio of the Ti 23 Cu 24 B 53 phase to the total area of the "Nd-rich phase and intergranular triangular region" is 3.4%; Alternatively, the R-T-B magnet comprises the following components: Nd 30 wt.%, Tb 0.6 wt.%, Cu 0.21 wt.%, Ti 0.45 wt.%, B 1 wt.%, Ga 0.02 wt.%, Al 0.04 wt.%, and Fe 67.68 wt.%, where wt.% is the mass percentage of each component in the total mass of all components; the intergranular triangular region of the R-T-B magnet contains Ti 22 Cu 26 B 52 phase, and the area ratio of the Ti 22 Cu 26 B 52 phase to the total area of the "Nd-rich phase and intergranular triangular region" is 3.6%; Alternatively, the R-T-B magnet comprises the following components: Nd 30.2 wt.%, Tb 0.4 wt.%, Cu 0.21 wt.%, Ti 0.45 wt.%, B 1 wt.%, Ga 0.02 wt.%, Al 0.08 wt.%, and Fe 67.64 wt.%, where wt.% is the mass percentage of each component in the total mass of all components; Ti is contained in the intergranular triangular region of the R-T-B magnet 25 Cu 25 B 50 phase, and the area ratio of the Ti 25 Cu 25 B 50 phase to the total area of the "Nd-rich phase and intergranular triangular region" is 3.5%; Alternatively, the R-T-B magnet comprises the following components: Nd 30.4 wt.%, Tb 0.2 wt.%, Cu 0.21 wt.%, Ti 0.45 wt.%, B 1 wt.%, Ga 0.02 wt.%, Al 0.02 wt.%, and Fe 67.7 wt.%, where wt.% is the mass percentage of each component in the total mass of all components; the intergranular triangular region of the R-T-B magnet contains Ti 24 Cu 26 B 50 phase, and the area ratio of the Ti 24 Cu 26 B 50 phase to the total area of the "Nd-rich phase and intergranular triangular region" is 3.5%; Alternatively, the R-T-B magnet comprises the following components: Nd 30.6 wt.%, Cu 0.21 wt.%, Ti 0.45 wt.%, B 1 wt.%, Ga 0.02 wt.%, Al 0.05 wt.%, and Fe 67.67 wt.%, where wt.% is the mass percentage of each component in the total mass of all components; the intergranular triangular region of the R-T-B magnet contains Ti 22 Cu 23 B 55 phase, and the area ratio of the Ti 22 Cu 23 B 55 phase to the total area of the "Nd-rich phase and intergranular triangular region" is 3.2%; Alternatively, the R-T-B magnet comprises the following components: Nd 29.6 wt.%, Tb 1 wt.%, Co 1 wt.%, Cu 0.21 wt.%, Ti 0.45 wt.%, B 1 wt.%, Ga 0.02 wt.%, Al 0.04 wt.%, and Fe 66.68 wt.%, where wt.% is the mass percentage of each component in the total mass of all components; Ti is contained in the intergranular triangular region of the R-T-B magnet 26 Cu 25 B 49 phase, and the area ratio of the Ti 26 Cu 25 B 49 phase to the total area of the "Nd-rich phase and intergranular triangular region" is 3.6%; Alternatively, the R-T-B magnet comprises the following components: Nd 30.6 wt.%, Co 1 wt.%, Cu 0.21 wt.%, Ti 0.45 wt.%, B 1 wt.%, Ga 0.02 wt.%, Al 0.06 wt.%, and Fe 66.66 wt.%, where wt.% is the mass percentage of each component in the total mass of all components; the intergranular triangular region of the R-T-B magnet contains Ti 24 Cu 25 B 51 phase, and the area ratio of the Ti 24 Cu 25 B 51 phase to the total area of the "Nd-rich phase and intergranular triangular region" is 3.2%; Alternatively, the R-T-B magnet comprises the following components: Nd 29.6 wt.%, Tb 1 wt.%, Cu 0.21 wt.%, Ti 0.45 wt.%, B 1 wt.%, Ga 0.19 wt.%, Al 0.05 wt.%, and Fe 67.5 wt.%, where wt.% is the mass percentage of each component in the total mass of all components; Ti is contained in the intergranular triangular region of the R-T-B magnet 23 Cu 25 B 52 phase, and the area ratio of the Ti 23 Cu 25 B 52 phase to the total area of the "Nd-rich phase and intergranular triangular region" is 2.9%; Alternatively, the R-T-B magnet comprises the following components: Nd 29.6 wt.%, Tb 1 wt.%, Cu 0.21 wt.%, Ti 0.55 wt.%, B 1 wt.%, Ga 0.02 wt.%, Al 0.05 wt.%, and Fe 67.57 wt.%, where wt.% is the mass percentage of each component in the total mass of all components; Ti is contained in the intergranular triangular region of the R-T-B magnet 27 Cu 25 B 48 phase, and the area ratio of the Ti 27 Cu 25 B 48 phase to the total area of the "Nd-rich phase and intergranular triangular region" is 3.5%; Alternatively, the R-T-B magnet comprises the following components: Nd 29.6 wt.%, Tb 1 wt.%, Cu 0.21 wt.%, Ti 0.7 wt.%, B 1 wt.%, Ga 0.02 wt.%, Al 0.04 wt.%, and Fe 67.43 wt.%, where wt.% is the mass percentage of each component in the total mass of all components; the intergranular triangular region of the R-T-B magnet contains Ti 25 Cu 25 B 50 phase, and the area ratio of the Ti 25 Cu 25 B 50 phase to the total area of the "Nd-rich phase and intergranular triangular region" is 3.4%; Alternatively, the R-T-B magnet comprises the following components: Nd 29.6 wt.%, Tb 1 wt.%, Cu 0.34 wt.%, Ti 0.45 wt.%, B 1 wt.%, Ga 0.02 wt.%, Al 0.05 wt.%, and Fe 67.54 wt.%, where wt.% is the mass percentage of each component in the total mass of all components; Ti is contained in the intergranular triangular region of the R-T-B magnet 24 Cu 24 B 52 phase, and the area ratio of the Ti 24 Cu 24 B 52 phase to the total area of the "Nd-rich phase and intergranular triangular region" is 3.7%; Alternatively, the R-T-B magnet comprises the following components: Nd 29.6 wt.%, Tb 1 wt.%, Cu 0.21 wt.%, Ti 0.45 wt.%, B 1.04 wt.%, Ga 0.02 wt.%, Al 0.04 wt.%, and Fe 67.64 wt.%, where wt.% is the mass percentage of each component in the total mass of all components; the intergranular triangular region of the R-T-B magnet contains Ti 21 Cu 21 B 58 phase, and the area ratio of the Ti 21 Cu 21 B 58 phase to the total area of the "Nd-rich phase and intergranular triangular region" is 3.6%; Or, the R-T-B magnet includes the following components: Nd 31 wt.%, Tb 1 wt.%, Cu 0.21 wt.%, Ti 0.45 wt.%, B 0.96 wt.%, Ga 0.02 wt.%, Al 0.06 wt.%, and Fe 66.3 wt.%, where wt.% is the mass percentage of each component in the total mass of all components; the intergranular triangular region of the R-T-B magnet contains Ti 25 Cu 23 B 52 phase, and the area ratio of the Ti 25 Cu 23 B 52 phase to the total area of the "neodymium-rich phase and intergranular triangular region" is 3.9%; Alternatively, the R-T-B magnet comprises the following components: Nd 29.8 wt.%, Tb 0.8 wt.%, Cu 0.21 wt.%, Ti 0.45 wt.%, B 1 wt.%, Ga 0.02 wt.%, Al 0.14 wt.%, and Fe 67.58 wt.%, where wt.% is the mass percentage of each component in the total mass of all components; Ti is contained in the intergranular triangular region of the R-T-B magnet 24 Cu 26 B 50 phase, and the area ratio of the Ti 24 Cu 26 B 50 phase to the total area of the "Nd-rich phase and intergranular triangular region" is 3.4%; Alternatively, the R-T-B magnet comprises the following components: Nd 29.6 wt.%, Tb 1 wt.%, Cu 0.45 wt.%, Ti 0.6 wt.%, B 1.15 wt.%, Ga 0.06 wt.%, Al 0.05 wt.%, and Fe 67.09 wt.%, where wt.% is the mass percentage of each component in the total mass of all components; the intergranular triangular region of the R-T-B magnet contains Ti 27 Cu 23 B 50 phase, and the area ratio of the Ti 27 Cu 23 B 50 phase to the total area of the "neodymium-rich phase and intergranular triangular region" is 3.5%; Alternatively, the R-T-B magnet comprises the following components: Nd 29.6 wt.%, Tb 1 wt.%, Cu 0.16 wt.%, Ti 0.4 wt.%, B 0.96 wt.%, Ga 0.01 wt.%, Al 0.07 wt.%, and Fe 67.8 wt.%, where wt.% is the mass percentage of each component in the total mass of all components; the intergranular triangular region of the R-T-B magnet contains Ti 24 Cu 25 B 51 phase, and the area ratio of the Ti 24 Cu 25 B 51 phase to the total area of the "Nd-rich phase and intergranular triangular region" is 3.4%; Alternatively, the R-T-B magnet comprises the following components: Nd 29.6 wt.%, Tb 1 wt.%, Cu 0.21 wt.%, Ti 0.4 wt.%, B 1 wt.%, Al 0.04 wt.%, and Fe 67.75 wt.%, where wt.% is the mass percentage of each component in the total mass of all components; the intergranular triangular region of the R-T-B magnet contains Ti 26 Cu 26 B 48 phase, and the area ratio of the Ti 26 Cu 26 B 48 phase to the total area of the "Nd-rich phase and intergranular triangular region" is 3.5%; Alternatively, the R-T-B magnet comprises the following components: Nd 30.1 wt.%, Dy 0.5 wt.%, Cu 0.21 wt.%, Ti 0.45 wt.%, B 1 wt.%, Ga 0.02 wt.%, Al 0.05 wt.%, and Fe 67.67 wt.%, where wt.% is the mass percentage of each component in the total mass of all components; Ti is contained in the intergranular triangular region of the R-T-B magnet 25 Cu 27 B 48 phase, and the area ratio of the Ti 25 Cu 27 B 48 phase to the total area of the "Nd-rich phase and intergranular triangular region" is 3.4%; Alternatively, the R-T-B magnet comprises the following components: Nd 28.6 wt.%, Dy 2 wt.%, Cu 0.21 wt.%, Ti 0.5 wt.%, B 1 wt.%, Ga 0.02 wt.%, Al 0.03 wt.%, and Fe 67.64 wt.%, where wt.% is the mass percentage of each component in the total mass of all components; the intergranular triangular region of the R-T-B magnet contains Ti 27 Cu 28 B 45 phase, and the area ratio of the Ti 27 Cu 28 B 45 phase to the total area of the "Nd-rich phase and intergranular triangular region" is 3.5%; Alternatively, the R-T-B magnet comprises the following components: Nd 29.6 wt.%, Tb 0.5 wt.%, Dy 0.5 wt.%, Cu 0.21 wt.%, Ti 0.48 wt.%, B 1 wt.%, Ga 0.02 wt.%, Al 0.06 wt.%, Fe 67.63 wt.%, where wt.% is the mass percentage of each component in the total mass of all components; the grain boundary triangular region of the R-T-B magnet contains Ti 24 Cu 24 B 52 phase, and the area ratio of the Ti 24 Cu 24 B 52 phase to the total area of the "Nd-rich phase and grain boundary triangular region" is 3.5%.

7. A method for preparing an R-T-B magnet, characterized in that, It includes the following steps: The raw material mixture of each component of the R-T-B magnet as described in any one of claims 1 to 4 and 6 is obtained by sintering treatment and aging treatment.

8. The method for preparing an R-T-B magnet according to claim 7, characterized in that, The temperature of the sintering treatment is 1000 to 1100 °C, such as 1080 °C. And / or, the time of the sintering treatment is 4 to 8 h, such as 6 h. And / or, the aging treatment includes a primary aging treatment and a secondary aging treatment. Wherein, the temperature of the primary aging treatment is preferably 860 to 920 °C, such as 880 °C or 900 °C; the time of the primary aging treatment is preferably 2.5 to 4 h, such as 3 h. Wherein, the temperature of the secondary aging treatment is preferably 460 to 530 °C, such as 500 °C, 510 °C, or 520 °C; the time of the secondary aging treatment is preferably 2.5 to 4 h, such as 3 h. And / or, when the R-T-B magnet further contains heavy rare earth elements, grain boundary diffusion is further included after the aging treatment. Among them, the temperature of the grain boundary diffusion is preferably 800 - 900 °C, such as 850 °C; the time of the grain boundary diffusion is preferably 5 - 10 h, such as 8 h; Among them, the addition method of the heavy rare earth element in the R-T-B magnet preferably adopts the method that 0 - 80% of the heavy rare earth element is added during melting and the remaining heavy rare earth elements are added during grain boundary diffusion, such as 25%, 30%, 40%, 50% or 67%; for example, when the heavy rare earth element in the R-T-B magnet is Tb and Tb is greater than 0.5 wt.%, 40 - 67% of Tb is added during melting and the remaining part is added during grain boundary diffusion; or for example, when the heavy rare earth elements in the R-T-B magnet are Tb and Dy, the Tb is added during melting and the Dy is added during grain boundary diffusion; or for example, when the heavy rare earth element in the R-T-B magnet is Tb and Tb is less than or equal to 0.5 wt.% or the heavy rare earth element in the R-T-B magnet is Dy, the heavy rare earth element in the R-T-B magnet is added during grain boundary diffusion; Among them, after the grain boundary diffusion, it preferably further includes a secondary aging treatment again; the temperature of the secondary aging treatment again is, for example, 460 - 530 °C, specifically 500 °C; the time of the secondary aging treatment again is, for example, 2.5 - 4 h, specifically 3 h.

9. The method for preparing an R-T-B magnet according to claim 7 or 8, characterized in that, Before the sintering treatment, it further includes the steps of melting, casting, hydrogen decrepitation crushing, fine crushing and magnetic field forming in sequence; Among them, the temperature of the melting is preferably below 1550 °C; Among them, the temperature of the casting is preferably 1390 - 1460 °C, such as 1400, 1420 °C or 1430 °C; Among them, the process of the hydrogen decrepitation crushing preferably undergoes hydrogen absorption, dehydrogenation and cooling treatment in sequence; Among them, the particle size of the powder obtained after the fine crushing is preferably 4.1 - 4.4 μm, such as 4.1 μm, 4.2 μm or 4.3 μm; Among them, the magnetic field strength of the magnetic field forming is preferably 1.8 - 2.5 T.

10. An R-T-B magnet obtained by the method for preparing an R-T-B magnet according to any one of claims 7 to 9.

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