R-T-B magnet material and preparation method and application thereof

Abstract

The invention discloses an R-T-B magnet material and a preparation method and application thereof. The preparation method of the R-T-B magnet material comprises the following steps that S1, R-T-B first powder is ground through a target airflow mill, and R-T-B second powder is obtained; wherein a target material is arranged in the target jet mill, and the target material comprises HR; hR is a heavy rare earth element and comprises Dy and / or Tb; and S2, the R-T-B second powder is pressed and sintered to prepare the R-T-B magnet material. The preparation method has the advantages of simplicity, high efficiency, high feasibility, wide applicability and the like, and the prepared R-T-B magnet material has excellent coercive force while having high residual magnetism.

Description

Technical Field

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

[0002] In order to obtain high-performance NdFeB magnets, it is usually possible to increase the HR (heavy rare earth) content in the shell, for example, adding a diffusion process after the magnet is made, such as patent application CN202310005209.6 "A thin film HRE diffusion source and preparation method, NdFeB magnet preparation method"; or preparing HRE alloy powder and then mixing the powder, such as patent application CN201210230846.5 "Method for preparing sintered NdFeB magnets". But overall, there are defects such as extended cycle, increased processing cost, and can only be used for thin-sheet products, that is, poor applicability.

[0003] Therefore, there is an urgent need for a simple, feasible and efficient process for preparing NdFeB magnets, specifically a HR addition process. Summary of the invention

[0004] In order to solve the above technical defects in the prior art, the present invention provides an RTB magnet material and a preparation method and application thereof. The preparation method has the advantages of being simple and efficient, highly feasible, and widely applicable, and the prepared RTB magnet material can have high remanence and excellent coercive force.

[0005] To achieve the above purpose, the present invention adopts the following technical solution.

[0006] The present invention provides a method for preparing an RTB magnet material, which comprises the following steps:

[0007] S1, RTB first powder is pulverized by target airflow milling to obtain RTB second powder;

[0008] Wherein, the target-type airflow mill is provided with a target material, and the target material includes HR; the HR is a heavy rare earth element, including Dy and / or Tb;

[0009] S2. The RTB second powder is pressed and sintered to obtain the RTB magnet material.

[0010] In the present invention, the RTB magnet material refers to a NdFeB magnet material containing R, T and B elements, wherein R refers to a rare earth element, T refers to a transition metal element such as Fe and Co, and B refers to boron.

[0011] In the present invention, the RTB first powder means a powder obtained by mixing the metal raw materials of the RTB magnet material according to a ratio, smelting, casting and crushing. It may be a coarse powder containing a large amount of internal crack flaky structure (different from the fine powder of the RTB second powder with uniform particle size, that is, the particle size is higher than the RTB second powder). Those skilled in the art will know its specific meaning.

[0012] The present invention uses a target material containing HR as an impact target for a target-type airflow mill, and uses it to make powder. It has been found through research that when the present invention uses a target material containing HR as an impact target, the particle size control and HR addition can be achieved simultaneously during the powder making process, and the diffusion of HR can be achieved during sintering without further adopting a diffusion process or additional powder addition. Compared with the HR addition process in the prior art, the present invention can ensure excellent diffusion performance during subsequent sintering with a trace amount of addition (not higher than 1wt%) while controlling the particle size, so that the obtained RTB magnet material has high remanence and significantly improves its coercive force.

[0013] In some embodiments, in step S1, the content of HR in the target material is 10wt%-100wt%, for example, 30wt%, 50wt% or 70wt%.

[0014] In some embodiments, in step S1, in the target material, the HR includes Dy, and the content of Dy is preferably 50-70 wt %.

[0015] In some embodiments, in step S1, in the target material, the HR includes Tb, and the content of Tb is preferably 30-50 wt %.

[0016] In some embodiments, in step S1, the target material further includes Fe, and the content of Fe is preferably 0-90wt%, such as 30wt%, 50wt% or 70wt%.

[0017] In some specific embodiments, in step S1, the target material includes: 30 wt% Dy and 70 wt% Fe.

[0018] In some specific embodiments, in step S1, the target material comprises: 50 wt% Dy and 50 wt% Fe.

[0019] In some specific embodiments, in step S1, the target material includes: 70 wt% Dy and 30 wt% Fe.

[0020] In some specific embodiments, in step S1, the target material includes: 30 wt% Tb and 70 wt% Fe.

[0021] In some specific embodiments, in step S1, the target material comprises: 50 wt% Tb and 50 wt% Fe.

[0022] In some specific embodiments, in step S1, the target material includes: 70 wt% Tb and 30 wt% Fe.

[0023] In some embodiments, in step S1, the powder making pressure is 500-700 kPa, preferably 600-620 kPa, for example 602 kPa, 603 kPa, 606 kPa, 608 kPa, 612 kPa, 614 kPa or 617 kPa.

[0024] In some embodiments, in step S1, the powder making is performed under an inert atmosphere; the inert atmosphere is a nitrogen atmosphere.

[0025] In some embodiments, in step S1, the RTB first powder includes the following components:

[0026] R: 28-33wt%; R is a rare earth element, and R includes Nd and Pr;

[0027] Al: 0-0.5wt%, and not 0;

[0028] Cu: 0.1-0.6wt%;

[0029] Co: 0.3-0.7wt%;

[0030] Ga: 0-0.3wt%, and not 0;

[0031] Ti: 0-0.4wt%, not 0;

[0032] B: 0.95-1.2wt%;

[0033] Fe: 62-69 wt %, wherein wt % is the percentage of the mass of each component to the total mass of the RTB first powder.

[0034] In some preferred embodiments, in step S1, the content of R in the first RTB powder is 29-31 wt%, for example, 30 wt%.

[0035] In some preferred embodiments, in step S1, the Nd content in the first RTB powder is 26-28 wt%, for example, 27 wt%.

[0036] In some preferred embodiments, in step S1, the content of Pr in the first RTB powder is 2-4 wt%, for example, 3 wt%.

[0037] In some preferred embodiments, in step S1, the content of Al in the first RTB powder is 0-0.1 wt %, and is not 0, for example, 0.05 wt %.

[0038] In some preferred embodiments, in step S1, the content of Cu in the first RTB powder is 0.1-0.3 wt%, for example 0.2 wt%.

[0039] In some preferred embodiments, in step S1, the content of Co in the first RTB powder is 0.4-0.6 wt%, for example, 0.5 wt%.

[0040] In some preferred embodiments, in step S1, the Ga content in the first RTB powder is 0.1-0.3 wt%, for example 0.3 wt%.

[0041] In some preferred embodiments, in step S1, the content of Ti in the first RTB powder is 0.1-0.3 wt%, for example 0.2 wt%.

[0042] In some preferred embodiments, in step S1, the content of B in the first RTB powder is 0.96-1 wt%, for example 0.98 wt%.

[0043] In some preferred embodiments, in step S1, the Fe content in the first RTB powder is 66-69 wt%, for example, 67.77 wt%.

[0044] In some specific embodiments, in step S1, the composition of the RTB first powder includes 3wt% Pr, 27wt% Nd, 0.05wt% Al, 0.2wt% Cu, 0.5wt% Co, 0.3wt% Ga, 0.2wt% Ti, 0.98wt% B and the balance Fe.

[0045] In the present invention, the melting process can be a conventional process in the art, such as melting in a melting furnace. The vacuum degree of the melting furnace is preferably lower than 15 Pa; and the melting temperature is preferably 1400-1550°C.

[0046] In the present invention, the casting process can be a conventional process in the art, such as a thin strip continuous casting method, an ingot casting method, a centrifugal casting method or a rapid quenching method, preferably a thin strip continuous casting method.

[0047] In the present invention, the crushing process can be a conventional process in the art, such as hydrogen crushing. The pressure of the hydrogen crushing is preferably 0.05-0.5MPa, such as 0.098MPa. The dehydrogenation temperature of the hydrogen crushing is preferably 350-550°C, such as 550°C. The dehydrogenation time of the hydrogen crushing is preferably 5-10h. The hydrogen crushing is preferably carried out under the condition of vacuuming and heating.

[0048] In the present invention, in step S1, the particle size D50 of the RTB first powder is 3.0-10.0 μm.

[0049] In some embodiments, in step S1, the particle size D50 of the RTB second powder is 3.0- 4.5 μm, for example 3.15μm, 3.55μm, 4.03μm, 4.15μm or 4.16μm or 4.43μm.

[0050] In the present invention, in step S2, the pressing process may be a conventional process in the art.

[0051] In some embodiments, in step S2, the sintering is a one-stage sintering, the sintering temperature is 1000-1100° C., and the sintering time is 4-8 hours.

[0052] In some embodiments, in step S2, the sintering is performed by heating in stages:

[0053] The first stage: the temperature is 150°C; the time is 1-3h, for example 1.5h;

[0054] The second stage: the temperature is 300°C; the time is 1-3h, for example 1.5h;

[0055] The third stage: the temperature is 550°C; the time is 1-3h, for example 1.5h;

[0056] The fourth stage: the temperature is 800°C; the time is 1-3h, for example 1.5h.

[0057] The fifth stage: the temperature is 1080°C; the time is 1-3h, for example 1.5h.

[0058] The present invention also provides an RTB magnet material, which is prepared by the above-mentioned preparation method of the RTB magnet material.

[0059] The present invention also provides an RTB magnet material, comprising a main phase and a grain boundary phase, wherein the grain boundary phase is uniformly distributed with heavy rare earth elements HR; the HR comprises Dy and / or Tb; and the content of the HR in the RTB magnet material is not higher than 1wt%.

[0060] In the present invention, the “heavy rare earth element HR is uniformly distributed in the grain boundary phase” may mean that HR is uniformly distributed only in the grain boundary phase, not in the main phase, and no HR-enriched region is formed on the surface of the RTB magnet material.

[0061] In some embodiments, the RTB magnet material includes the following components:

[0062] HR: 0-1wt%, and not 0;

[0063] LR: 28-31wt%; the LR is a light rare earth element, and the LR includes Nd and Pr;

[0064] Al: 0-0.5wt%, and not 0;

[0065] Cu: 0.1-0.6wt%;

[0066] Co: 0.3-0.7wt%;

[0067] Ga: 0-0.3wt%, and not 0;

[0068] Ti: 0-0.4wt%, not 0;

[0069] B: 0.95-1.2wt%;

[0070] Fe: 62-69 wt%, wherein wt% is the percentage of the mass of each component to the total mass of the RTB magnet material.

[0071] In some embodiments, the content of HR in the RTB magnet material is 0.05-1wt%, for example 0.173wt%, 0.211wt%, 0.233wt%, 0.241wt%, 0.248wt%, 0.283wt%, 0.284wt%, 0.373wt%, 0.391wt%, 0.491wt%, 0.618wt%, 0.627wt% or 0.782wt%.

[0072] In some embodiments, the HR in the RTB magnet material includes Dy, and the content of Dy is preferably 0.2-0.8wt%, for example 0.211wt%, 0.233wt%, 0.241wt%, 0.248wt%, 0.284wt%, 0.373wt%, 0.391wt%, 0.618wt% or 0.782wt%.

[0073] In some embodiments, HR in the RTB magnet material includes Tb, and the content of Td is preferably 0.1-0.7 wt%, such as 0.173 wt%, 0.283 wt%, 0.491 wt% or 0.627 wt%.

[0074] In some embodiments, the content of LR in the RTB magnet material is 29-31 wt%, for example, 29.383 wt%, 29.505 wt%, 29.607 wt%, 29.621 wt%, 29.624 wt%, 29.628 wt%, 29.630 wt%, 29.640 wt%, 29.658 wt%, 29.670 wt%, 29.693 wt% or 29.739 wt%.

[0075] In some embodiments, the Nd content in the RTB magnet material is 26-28wt%, for example, 26.679wt%, 26.693wt%, 26.712wt%, 26.719wt%, 26.720wt%, 26.734wt%, 26.736wt%, 26.740wt%, 26.741wt%, 26.767wt%, 26.778wt%, 26.794wt% or 26.817wt%.

[0076] In some embodiments, the Pr content in the RTB magnet material is 2-4wt%, for example, 2.704wt%, 2.812wt%, 2.873wt%, 2.883wt%, 2.887wt%, 2.892wt%, 2.894wt%, 2.895wt%, 2.899wt%, 2.909wt%, 2.910wt%, 2.918wt% or 2.922wt%.

[0077] In some embodiments, the Al content in the RTB magnet material is 0-0.1 wt %, and is not 0, for example, 0.041 wt %, 0.042 wt %, 0.043 wt %, 0.044 wt %, 0.045 wt %, 0.046 wt %, 0.047 wt % or 0.048 wt %.

[0078] In some embodiments, the content of Cu in the RTB magnet material is 0.191 wt %, 0.192 wt %, 0.193 wt %, 0.194 wt %, 0.195 wt %, 0.196 wt % or 0.197 wt %.

[0079] In some embodiments, the Co content in the RTB magnet material is 0.4-0.6 wt%, for example 0.503 wt%, 0.504 wt%, 0.505 wt%, 0.506 wt%, 0.507 wt%, 0.508 wt%, 0.510 wt%, 0.512 wt%, 0.513 wt% or 0.515 wt%.

[0080] In some embodiments, the Ga content in the RTB magnet material is 0.1-0.3 wt%, for example, 0.289 wt%, 0.291 wt%, 0.292 wt%, 0.293 wt%, 0.294 wt%, 0.295 wt%, 0.296 wt% or 0.297 wt%.

[0081] In some embodiments, the Ti content in the RTB magnet material is 0-0.3 wt %, and is not 0, for example, 0.202 wt %, 0.203 wt %, 0.204 wt %, 0.205 wt %, 0.206 wt %, 0.208 wt %, 0.209 wt %, 0.211 wt % or 0.213 wt %.

[0082] In some embodiments, the content of B in the RTB magnet material is 0.96-1 wt %, such as 0.972 wt %, 0.974 wt %, 0.975 wt %, 0.976 wt %, 0.977 wt % or 0.978 wt %.

[0083] In some embodiments, the Fe content in the RTB magnet material is 66-69wt%, for example, 67.353wt%, 67.529wt%, 67.541wt%, 67.658wt%, 67.734wt%, 67.796wt%, 67.824wt%, 67.898wt%, 67.924wt%, 67.934wt%, 67.945wt%, 67.987wt% or 68.000wt%.

[0084] In some specific embodiments, the composition of the RTB magnet material includes 0.241wt% Dy, 2.910wt% Pr, 26.720wt% Nd, 0.048wt% Al, 0.192wt% Cu, 0.507wt% Co, 0.296wt% Ga, 0.211wt% Ti, 0.977wt% B and the balance Fe.

[0085] In some specific embodiments, the composition of the RTB magnet material includes 0.373wt% Dy, 2.892wt% Pr, 26.778wt% Nd, 0.047wt% Al, 0.194wt% Cu, 0.503wt% Co, 0.296wt% Ga, 0.208wt% Ti, 0.975wt% B and the balance Fe.

[0086] In some specific embodiments, the composition of the RTB magnet material includes 0.618wt% Dy, 2.894wt% Pr, 26.736wt% Nd, 0.048wt% Al, 0.196wt% Cu, 0.505wt% Co, 0.293wt% Ga, 0.203wt% Ti, 0.978wt% B and the balance Fe.

[0087] In some specific embodiments, the composition of the RTB magnet material includes 0.782wt% Dy, 2.873wt% Pr, 26.767wt% Nd, 0.046wt% Al, 0.196wt% Cu, 0.506wt% Co, 0.294wt% Ga, 0.209wt% Ti, 0.974wt% B and the balance Fe.

[0088] In some specific embodiments, the composition of the RTB magnet material includes 0.173wt% Tb, 2.918wt% Pr, 26.740wt% Nd, 0.048wt% Al, 0.195wt% Cu, 0.505wt% Co, 0.296wt% Ga, 0.202wt% Ti, 0.978wt% B and the balance Fe.

[0089] In some specific embodiments, the composition of the RTB magnet material includes 0.283wt% Tb, 2.899wt% Pr, 26.794wt% Nd, 0.046wt% Al, 0.197wt% Cu, 0.508wt% Co, 0.297wt% Ga, 0.204wt% Ti, 0.976wt% B and the balance Fe.

[0090] In some specific embodiments, the composition of the RTB magnet material includes 0.491wt% Tb, 2.909wt% Pr, 26.719wt% Nd, 0.045wt% Al, 0.193wt% Cu, 0.512wt% Co, 0.292wt% Ga, 0.206wt% Ti, 0.975wt% B and the balance Fe.

[0091] In some specific embodiments, the composition of the RTB magnet material includes 0.627wt% Tb, 2.887wt% Pr, 26.734wt% Nd, 0.043wt% Al, 0.194wt% Cu, 0.503wt% Co, 0.294wt% Ga, 0.205wt% Ti, 0.972wt% B and the balance Fe.

[0092] In some specific embodiments, the composition of the RTB magnet material includes 0.248wt% Dy, 2.895wt% Pr, 26.712wt% Nd, 0.046wt% Al, 0.193wt% Cu, 0.504wt% Co, 0.291wt% Ga, 0.203wt% Ti, 0.974wt% B and the balance Fe.

[0093] In some specific embodiments, the composition of the RTB magnet material includes 0.233wt% Dy, 2.883wt% Pr, 26.741wt% Nd, 0.044wt% Al, 0.192wt% Cu, 0.510wt% Co, 0.295wt% Ga, 0.206wt% Ti, 0.972wt% B and the balance Fe.

[0094] In some specific embodiments, the composition of the RTB magnet material includes 0.211 wt % Dy, 2.922 wt % Pr, 26.817 wt % Nd, 0.048 wt % Al, 0.196 wt % Cu, 0.504 wt % Co, 0.297 wt % Ga, 0.203 wt % Ti, 0.978 wt % B and the balance Fe.

[0095] In some specific embodiments, the composition of the RTB magnet material includes 0.284wt% Dy, 2.812wt% Pr, 26.693wt% Nd, 0.042wt% Al, 0.191wt% Cu, 0.513wt% Co, 0.291wt% Ga, 0.209wt% Ti, 0.978wt% B and the balance Fe.

[0096] In some specific embodiments, the composition of the RTB magnet material includes 0.391 wt % Dy, 2.704 wt % Pr, 26.679 wt % Nd, 0.041 wt % Al, 0.191 wt % Cu, 0.515 wt % Co, 0.289 wt % Ga, 0.213 wt % Ti, 0.977 wt % B and the balance Fe.

[0097] The present invention also provides an application of the RTB magnet material as mentioned above in magnetic steel.

[0098] On the basis of being in accordance with the common sense in the art, the above-mentioned preferred conditions can be arbitrarily combined to obtain the preferred embodiments of the present invention.

[0099] The reagents and raw materials used in the present invention are commercially available.

[0100] The positive and progressive effects of the present invention are:

[0101] The preparation method of the present invention selects a target material containing HR on the basis of target airflow milling, so that the particle size control and the addition of trace HR are simultaneously realized in the powder making process, and the diffusion of the shell HR is completed during sintering, without further adopting a diffusion process or additional powder mixing process, and the obtained RTB magnet material has high remanence and excellent coercive force; and the whole preparation method has the advantages of simplicity, high efficiency, high feasibility, wide applicability, low cost, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0102] Figure 1 This is a crystal phase micrograph of the RTB magnet material obtained in Example 5 of the present invention.

[0103] Figure 2 for Figure 1 The center line 1 is scanned to obtain the Tb content map.

[0104] Figure 3 This is the Tb distribution diagram of the RTB magnet material obtained in Example 5 of the present invention.

[0105] Figure 4 This is the Tb distribution diagram of the RTB magnet material obtained by the existing diffusion process. DETAILED DESCRIPTION

[0106] The present invention is further described below by way of examples, but the present invention is not limited to the scope of the examples. The experimental methods in the following examples without specifying specific conditions are carried out according to conventional methods and conditions, or selected according to the product specifications.

[0107] In the following examples and comparative examples, the obtained RTB material is prepared by the following steps:

[0108] 1. Preparation of RTB first powder

[0109] According to the formula of 3% Pr, 27% Nd, 0.05% Al, 0.2% Cu, 0.5% Co, 0.3% Ga, 0.2% Ti, 0.98% B and balance Fe, the corresponding raw materials are smelted to obtain the corresponding NdFeB alloy flakes, which are hydrogen crushed at a pressure of 0.098 MPa and a dehydrogenation temperature of 550°C, and are carried out under the conditions of vacuuming and heating to obtain NdFeB coarse powder, i.e., RTB first powder (containing a large amount of coarse powder with an internal crack flaky structure).

[0110] 2. Preparation of RTB Second Powder

[0111] The target-type jet mills equipped with different target materials were respectively used to prepare RTB second powders with a particle size D50 of 3.0-4.5 μm under different grinding gas pressures (grinding gas was nitrogen).

[0112] 3. Preparation of RTB magnet materials

[0113] The RTB second powder is pressed (using normal orientation pressing) to prepare a compact; then sintered at a multi-stage degassing temperature of 150°C-300°C-550°C-800°C-1080°C and a degassing time of 90 minutes to obtain an RTB magnet material.

[0114] Examples 1-9 and Comparative Examples 1-2

[0115] According to the above process, the corresponding RTB magnet materials were prepared with the process parameters in Table 1.

[0116] Table 1

[0117]

[0118] Effect Example

[0119] 1. Determination of rare earth element content

[0120] The mass contents of rare earth elements in the RTB magnet materials prepared in the examples and comparative examples were determined using a high frequency inductively coupled plasma optical emission spectrometer (ICP-OES).

[0121] 2. Magnetic properties determination

[0122] The NIM-62000 permanent magnet material precision measurement system of China National Institute of Metrology was used to measure the remanence (Br) and coercive force (Hcj) at a test temperature of 20°C.

[0123] The results are shown in Tables 2 and 3.

[0124] Table 2

[0125]

[0126] Table 3

[0127]

[0128]

[0129] After testing, the RTB magnet material obtained in the embodiment of the present invention includes a main phase and a grain boundary phase, specifically: Figure 1 and Figure 2 As shown, they are respectively the crystal phase micrograph of the RTB magnet material obtained in Example 5 of the present invention and the corresponding line scanning result; Figure 3 The figure shows an EPMA surface scanning micrograph of the RTB magnet material (the shooting equipment information is: manufacturer: JEOL; model: JXA-8530F).

[0130] The results show that Tb in the RTB magnet material obtained by the present invention is distributed in the grain boundary phase ( Figure 1 White bright spot area in the middle), achieving the grain boundary diffusion effect ( Figure 1 and Figure 2 ), and its concentration is evenly distributed from the surface to the inside ( Figure 3 ), that is, there is no Tb-rich area on the surface, which can be used to produce thick slice products; in the grain boundary phase of the material obtained by the existing diffusion process, HR enters the interior of the magnet through the grain boundary phase under the action of concentration difference, so it is inevitable to form HR-rich area on the surface (such as Figure 4 As shown, the material obtained by the existing diffusion process has a Tb diffusion weight gain of 0.674wt%), and the diffusion depth is limited, which is only suitable for preparing thin sheets (thickness is generally less than 10mm).

[0131] Combined with the above results, it can be seen that the RTB magnet material prepared by the specific HR adding process of the present invention has a high Br and the Hcj can be increased by more than 0.5KOe when the HR addition amount is less than 1wt%, and the HR is evenly distributed in the grain boundary phase of the magnet material, and can be used to produce thick sheet products; it shows that the preparation method of the present invention can simultaneously carry out particle size control and trace HR addition and distribution during the powder making process, and effectively improve the performance of the final RTB magnet material, especially the coercive force; and the entire preparation method has the advantages of simplicity, high efficiency, high feasibility, wide applicability, low cost, etc.

Claims

1. A method for preparing an RTB magnet material, characterized in that: The preparation method of the RTB magnet material comprises the following steps: S1, RTB first powder is pulverized by target airflow milling to obtain RTB second powder; Wherein, the target-type airflow mill is provided with a target material, and the target material includes HR; the HR is a heavy rare earth element, including Dy and / or Tb; S2. The RTB second powder is pressed and sintered to obtain the RTB magnet material.

2. The method for preparing the RTB magnet material according to claim 1, characterized in that: In step S1, in the target material, the content of HR is 10wt%-100wt%, for example, 30wt%, 50wt% or 70wt%; The HR includes Dy, and the content of Dy is preferably 50-70wt%; The HR includes Tb, and the content of Tb is preferably 30-50wt%; And / or, in step S1, the target material further comprises Fe, and the content of Fe is preferably 0-90wt%, such as 30wt%, 50wt% or 70wt%; Preferably, in step S1, the target material is composed of any one of the following compositions: (1) 30 wt% Dy and 70 wt% Fe; (2) 50 wt% Dy and 50 wt% Fe; (3) 70 wt% Dy and 30 wt% Fe; (4) 30 wt% Tb and 70 wt% Fe; (5) 50 wt% Tb and 50 wt% Fe; (6) 70 wt% Tb and 30 wt% Fe.

3. The method for preparing the RTB magnet material according to claim 1, characterized in that: In step S1, the powder making pressure is 500-700 kPa, preferably 600-620 kPa, such as 602 kPa, 603 kPa, 606 kPa, 608 kPa, 612 kPa, 614 kPa or 617 kPa; And / or, in step S1, the powder making is carried out under an inert atmosphere; the inert atmosphere is, for example, a nitrogen atmosphere; And / or, in step S1, the RTB first powder includes the following components: R: 28-33wt%; R is a rare earth element, and R includes Nd and Pr; Al: 0-0.5wt%, and not 0; Cu: 0.1-0.6wt%; Co: 0.3-0.7wt%; Ga: 0-0.3wt%, and not 0; Ti: 0-0.4wt%, not 0; B: 0.95-1.2wt%; Fe: 62-69 wt%, wherein wt% is the percentage of the mass of each component to the total mass of the RTB first powder; Preferably, in step S1, the content of R in the first RTB powder is 29-31 wt%, for example, 30 wt%; Preferably, in step S1, the Nd content in the first RTB powder is 26-28wt%, for example, 27wt%; Preferably, in step S1, the content of Pr in the first RTB powder is 2-4wt%, for example, 3wt%; Preferably, in step S1, the content of Al in the first RTB powder is: 0-0.1wt%, and is not 0, for example, 0.05wt%; Preferably, in step S1, the content of Cu in the first RTB powder is 0.1-0.3wt%, for example 0.2wt%; Preferably, in step S1, the content of Co in the first RTB powder is 0.4-0.6wt%, for example 0.5wt%; Preferably, in step S1, the Ga content in the first RTB powder is 0.1-0.3wt%, for example 0.3wt%; Preferably, in step S1, the content of Ti in the first RTB powder is 0.1-0.3wt%, for example 0.2wt%; Preferably, in step S1, the content of B in the first RTB powder is 0.96-1wt%, for example 0.98wt%; Preferably, in step S1, the Fe content in the first RTB powder is 66-69wt%, for example 67.77wt%; More preferably, in step S1, the composition of the RTB first powder includes 3wt% Pr, 27wt% Nd, 0.05wt% Al, 0.2wt% Cu, 0.5wt% Co, 0.3wt% Ga, 0.2wt% Ti, 0.98wt% B and the balance Fe.

4. The method for preparing the RTB magnet material according to claim 1, characterized in that: In step S1, the particle size D50 of the RTB first powder is 3.0-10.0 μm; and / or, in step S1, the particle size D50 of the RTB second powder is 3.0-4.5 μm, for example, 3.15 μm, 3.55 μm, 4.03 μm, 4.15 μm, 4.16 μm or 4.43 μm; And / or, in step S2, the sintering is performed by heating in stages: The first stage: the temperature is 150°C; the time is 1-3h, for example 1.5h; The second stage: the temperature is 300°C; the time is 1-3h, for example 1.5h; The third stage: the temperature is 550°C; the time is 1-3h, for example 1.5h; The fourth stage: the temperature is 800°C; the time is 1-3h, for example 1.5h; The fifth stage: the temperature is 1080°C; the time is 1-3h, for example 1.5h.

5. An RTB magnet material, characterized in that: The RTB magnet material is prepared by the method for preparing the RTB magnet material according to any one of claims 1 to 4.

6. An RTB magnet material, characterized in that: The RTB magnet material comprises a main phase and a grain boundary phase, in which the heavy rare earth element HR is uniformly distributed; the HR comprises Dy and / or Tb; and the content of the HR in the RTB magnet material is not higher than 1wt%.

7. The RTB magnet material according to claim 6, characterized in that The RTB magnet material comprises the following components: HR: 0-1wt%, and not 0; LR: 28-31wt%; the LR is a light rare earth element, and the LR includes Nd and Pr; Al: 0-0.5wt%, and not 0; Cu: 0.1-0.6wt%; Co: 0.3-0.7wt%; Ga: 0-0.3wt%, and not 0; Ti: 0-0.4wt%, not 0; B: 0.95-1.2wt%; Fe: 62-69 wt%, wherein wt% is the percentage of the mass of each component to the total mass of the RTB magnet material.

8. The RTB magnet material according to claim 7, characterized in that The content of HR in the RTB magnet material is 0.05-1wt%, such as 0.173wt%, 0.211wt%, 0.233wt%, 0.241wt%, 0.248wt%, 0.283wt%, 0.284wt%, 0.373wt%, 0.391wt%, 0.491wt%, 0.618wt%, 0.627wt% or 0.782wt%; The HR includes Dy, and the content of Dy is preferably 0.2-0.8wt%, such as 0.211wt%, 0.233wt%, 0.241wt%, 0.248wt%, 0.284wt%, 0.373wt%, 0.391wt%, 0.618wt% or 0.782wt%; The HR includes Tb, and the content of Td is preferably 0.1-0.7wt%, such as 0.173wt%, 0.283wt%, 0.491wt% or 0.627wt%; and / or, the content of LR in the RTB magnet material is 29-31 wt%, such as 29.383 wt%, 29.505 wt%, 29.607 wt%, 29.621 wt%, 29.624 wt%, 29.628 wt%, 29.630 wt%, 29.640 wt%, 29.658 wt%, 29.670 wt%, 29.693 wt% or 29.739 wt%; and / or, the Nd content in the RTB magnet material is 26-28wt%, such as 26.679wt%, 26.693wt%, 26.712wt%, 26.719wt%, 26.720wt%, 26.734wt%, 26.736wt%, 26.740wt%, 26.741wt%, 26.767wt%, 26.778wt%, 26.794wt% or 26.817wt%; and / or, the content of Pr in the RTB magnet material is 2-4wt%, such as 2.704wt%, 2.812wt%, 2.873wt%, 2.883wt%, 2.887wt%, 2.892wt%, 2.894wt%, 2.895wt%, 2.899wt%, 2.909wt%, 2.910wt%, 2.918wt% or 2.922wt%; And / or, the content of Al in the RTB magnet material is: 0-0.1wt%, and is not 0, such as 0.041wt%, 0.042wt%, 0.043wt%, 0.044wt%, 0.045wt%, 0.046wt%, 0.047wt% or 0.048wt%; and / or, the content of Cu in the RTB magnet material is 0.1-0.3 wt%, such as 0.191 wt%, 0.192 wt%, 0.193 wt%, 0.194 wt%, 0.195 wt%, 0.196 wt% or 0.197 wt%; and / or, the content of Co in the RTB magnet material is 0.4-0.6wt%, such as 0.503wt%, 0.504wt%, 0.505wt%, 0.506wt%, 0.507wt%, 0.508wt%, 0.510wt%, 0.512wt%, 0.513wt% or 0.515wt%; and / or, the Ga content in the RTB magnet material is 0.1-0.3 wt%, such as 0.289 wt%, 0.291 wt%, 0.292 wt%, 0.293 wt%, 0.294 wt%, 0.295 wt%, 0.296 wt% or 0.297 wt%; and / or, the content of Ti in the RTB magnet material is 0-0.3wt%, and is not 0, such as 0.202wt%, 0.203wt%, 0.204wt%, 0.205wt%, 0.206wt%, 0.208wt%, 0.209wt%, 0.211wt% or 0.213wt%; and / or, the content of B in the RTB magnet material is 0.96-1wt%, such as 0.972wt%, 0.974wt%, 0.975wt%, 0.976wt%, 0.977wt% or 0.978wt%; And / or, the Fe content in the RTB magnet material is 66-69wt%, for example, 67.353wt%, 67.529wt%, 67.541wt%, 67.658wt%, 67.734wt%, 67.796wt%, 67.824wt%, 67.898wt%, 67.924wt%, 67.934wt%, 67.945wt%, 67.987wt% or 68.000wt%.

9. The RTB magnet material according to claim 8, characterized in that The composition of the RTB magnet material includes 0.241wt% Dy, 2.910wt% Pr, 26.720wt% Nd, 0.048wt% Al, 0.192wt% Cu, 0.507wt% Co, 0.296wt% Ga, 0.211wt% Ti, 0.977wt% B and the balance Fe; Alternatively, the composition of the RTB magnet material includes 0.373wt% Dy, 2.892wt% Pr, 26.778wt% Nd, 0.047wt% Al, 0.194wt% Cu, 0.503wt% Co, 0.296wt% Ga, 0.208wt% Ti, 0.975wt% B and the balance Fe; Alternatively, the composition of the RTB magnet material includes 0.618wt% Dy, 2.894wt% Pr, 26.736wt% Nd, 0.048wt% Al, 0.196wt% Cu, 0.505wt% Co, 0.293wt% Ga, 0.203wt% Ti, 0.978wt% B and the balance Fe; Alternatively, the composition of the RTB magnet material includes 0.782wt% Dy, 2.873wt% Pr, 26.767wt% Nd, 0.046wt% Al, 0.196wt% Cu, 0.506wt% Co, 0.294wt% Ga, 0.209wt% Ti, 0.974wt% B and the balance Fe; Alternatively, the composition of the RTB magnet material includes 0.173wt% Tb, 2.918wt% Pr, 26.740wt% Nd, 0.048wt% Al, 0.195wt% Cu, 0.505wt% Co, 0.296wt% Ga, 0.202wt% Ti, 0.978wt% B and the balance Fe; Alternatively, the composition of the RTB magnet material includes 0.283wt% Tb, 2.899wt% Pr, 26.794wt% Nd, 0.046wt% Al, 0.197wt% Cu, 0.508wt% Co, 0.297wt% Ga, 0.204wt% Ti, 0.976wt% B and the balance Fe; Alternatively, the composition of the RTB magnet material includes 0.491wt% Tb, 2.909wt% Pr, 26.719wt% Nd, 0.045wt% Al, 0.193wt% Cu, 0.512wt% Co, 0.292wt% Ga, 0.206wt% Ti, 0.975wt% B and the balance Fe; Alternatively, the composition of the RTB magnet material includes 0.627wt% Tb, 2.887wt% Pr, 26.734wt% Nd, 0.043wt% Al, 0.194wt% Cu, 0.503wt% Co, 0.294wt% Ga, 0.205wt% Ti, 0.972wt% B and the balance Fe; Alternatively, the composition of the RTB magnet material includes 0.248wt% Dy, 2.895wt% Pr, 26.712wt% Nd, 0.046wt% Al, 0.193wt% Cu, 0.504wt% Co, 0.291wt% Ga, 0.203wt% Ti, 0.974wt% B and the balance Fe; Alternatively, the composition of the RTB magnet material includes 0.233wt% Dy, 2.883wt% Pr, 26.741wt% Nd, 0.044wt% Al, 0.192wt% Cu, 0.510wt% Co, 0.295wt% Ga, 0.206wt% Ti, 0.972wt% B and the balance Fe; Alternatively, the composition of the RTB magnet material includes 0.211wt% Dy, 2.922wt% Pr, 26.817wt% Nd, 0.048wt% Al, 0.196wt% Cu, 0.504wt% Co, 0.297wt% Ga, 0.203wt% Ti, 0.978wt% B and the balance Fe; Alternatively, the composition of the RTB magnet material includes 0.284wt% Dy, 2.812wt% Pr, 26.693wt% Nd, 0.042wt% Al, 0.191wt% Cu, 0.513wt% Co, 0.291wt% Ga, 0.209wt% Ti, 0.978wt% B and the balance Fe; Alternatively, the composition of the RTB magnet material includes 0.391wt% Dy, 2.704wt% Pr, 26.679wt% Nd, 0.041wt% Al, 0.191wt% Cu, 0.515wt% Co, 0.289wt% Ga, 0.213wt% Ti, 0.977wt% B and the balance Fe.

10. Use of the RTB magnet material according to any one of claims 5 to 9 in magnetic steel.

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