Rare earth permanent magnet, sintered magnet material, method of manufacturing, and use

Abstract

The application discloses a rare earth permanent magnet, a sintered magnet material, a preparation method and application. The sintered magnet material comprises a first component and a second component. The first component comprises R: 29mas% to 33mas%, wherein R is a rare earth element; B: 0.86mas% to 1mas%; Cu: 0 to 0.5mas% and not 0; Ga: 0 to 0.5mas% and not 0; and Fe: 64mas% to 70mas%. The second component comprises an antioxidant and a high-melting-point carbide. The high-melting-point carbide comprises one or more of titanium carbide, zirconium carbide, chromium carbide, niobium carbide, tantalum carbide, molybdenum carbide, tungsten carbide, vanadium carbide and hafnium carbide. The content of the high-melting-point carbide is 0.1 to 0.5mas%, and mas% is the mass percentage of each component in the sintered magnet material. The remanence and coercive force of the sintered magnet can be simultaneously maintained at a high level.

Description

TECHNICAL FIELD

[0001] The present application relates to a rare earth permanent magnet, a sintered magnet material, a preparation method, and an application. BACKGROUND

[0002] Sintered neodymium-iron-boron magnets are the strongest permanent magnets in the present age, which have excellent characteristics such as high magnetic energy product and high cost performance, and are now applied in the fields of aviation, aerospace, microwave communication technology, electronics, electroacoustics, electromechanics, etc. However, with the continuous expansion of the application range of permanent magnets, the demand for the same is also increasing, and higher requirements for the magnetic properties of the permanent magnets are also put forward.

[0003] In the process of preparing neodymium-iron-boron magnet materials in the prior art, a certain amount of lubricant or antioxidant will be mixed in during the airflow milling process or the forming process, that is, a certain amount of carbon element will be introduced, and a high carbon content will lead to a decrease in coercivity.

[0004] Therefore, there is an urgent need for a neodymium-iron-boron magnet material that still has high magnetic properties even if an antioxidant is added during the preparation process. SUMMARY

[0005] The technical problem to be solved by the present application is to overcome the defect that the introduction of an antioxidant in the prior art leads to a high carbon content, resulting in a decrease in coercivity, and to provide a rare earth permanent magnet, a sintered magnet material, a preparation method, and an application.

[0006] The inventor has found through creative labor that adding a high-melting-point carbide before magnet orientation forming can enable a rare earth permanent magnet to which a traditional antioxidant is added to still have excellent magnetic properties even in the case of a high carbon content; the reason is that the high-melting-point carbide will decompose during sintering, on the one hand, the carbon after decomposition forms a (face-centered cubic) fcc structure of rare earth carbide at the three-pronged grain boundary, and during the subsequent secondary aging process, a (hexagonal close-packed) hcp structure of rare earth carbide and a RE-Cu-Fe-C-Ga grain boundary phase are formed, the two kinds of grain boundary structures have better wettability to the main phase, and the continuity of the grain boundary is strengthened, thereby playing a better magnetic isolation role; on the other hand, the high-melting-point elements obtained by the decomposition of the high-melting-point carbide are distributed on the surface of the NdFeB main phase grain, thereby playing a role of magnetic domain pinning, and the synergistic effect of the foregoing two aspects enables the rare earth permanent magnet to still maintain good magnetic properties.

[0007] The present application solves the above technical problems by the following scheme:

[0008] The present application provides a sintered magnet material, which comprises a first component and a second component, and the first component comprises, in terms of mass percentage:

[0009] R: 29mas% to 33mas%, the R being a rare earth element;

[0010] B: 0.86 to 1 mas%;

[0011] Cu: 0 to 0.5 mas%, and not 0;

[0012] Ga: 0 to 0.5 mas%, and not 0;

[0013] Fe: 64 to 70 mas%;

[0014] The second component includes an antioxidant and a high-melting-point carbide, the high-melting-point carbide including one or more of titanium carbide, zirconium carbide, chromium carbide, niobium carbide, tantalum carbide, molybdenum carbide, tungsten carbide, vanadium carbide, and hafnium carbide; the high-melting-point carbide being included in an amount of 0.1 to 0.5 mas%, mas% being the mass percentage of each component with respect to the material for sintered magnets.

[0015] In the present application, preferably, the content of R is 29.5 to 32 mas%, for example, 29.6 mas% or 31 mas%, mas% being the mass percentage of each component with respect to the material for sintered magnets.

[0016] In the present application, preferably, R includes PrNd and / or Nd.

[0017] When R includes PrNd, the content of PrNd is preferably 0 to 33 mas%, and not 0, for example, 29.5 mas% or 31 mas%, mas% being the mass percentage of each component with respect to the material for sintered magnets.

[0018] When R includes Nd, the content of Nd is preferably 0 to 33 mas%, and not 0, for example, 29.5 mas%, mas% being the mass percentage of each component with respect to the material for sintered magnets.

[0019] In the present application, preferably, R includes a heavy rare earth element RH. Preferably, the content of RH is 0 to 2.5 mas%, and not 0, mas% being the mass percentage of each component with respect to the material for sintered magnets. Preferably, RH includes one or more of Tb, Dy, Ho, and Gd. When RH includes Tb, the content of Tb is preferably 0 to 0.5 mas%, and not 0, for example, 0.1 mas%, mas% being the mass percentage of each component with respect to the material for sintered magnets. When RH includes Dy, the content of Dy is preferably 0 to 2.5 mas%, and not 0, mas% being the mass percentage of each component with respect to the material for sintered magnets.

[0020] In the present application, the content of B is preferably 0.86 mas% to 0.99 mas%, for example, 0.88 mas% or 0.95 mas%, mas% being the mass percentage of each component with respect to the material for sintered magnet.

[0021] In the present application, the content of Cu is preferably 0 to 0.4 mas% and not 0, for example, 0.16 mas% or 0.3 mas%, mas% being the mass percentage of each component with respect to the material for sintered magnet.

[0022] In the present application, the content of Ga is preferably 0.05 mas% to 0.5 mas%, for example, 0.25 mas%, mas% being the mass percentage of each component with respect to the material for sintered magnet.

[0023] In the present application, the content of Fe is preferably 64.5 mas% to 69 mas%, for example, 68.78 mas%,

[0024] 66.72 mas% or 64.74 mas%, mas% being the mass percentage of each component with respect to the material for sintered magnet.

[0025] In the present application, the antioxidant can be an antioxidant or lubricant conventionally used in the art, for example, magnesium stearate and / or tributyl borate. The content of the antioxidant is generally 0.05 mas% to 0.15 mas%.

[0026] In the present application, the high-melting-point carbide preferably includes one or more of titanium carbide, zirconium carbide, chromium carbide, niobium carbide, tantalum carbide and tungsten carbide. The content of the high-melting-point carbide is preferably 0.2 to 0.5 mas%, mas% being the mass percentage of each component with respect to the material for sintered magnet.

[0027] In the present application, the production process of the sintered magnet generally includes the steps of coarse pulverization and fine pulverization molding. The high-melting-point carbide in the second component is preferably added after the fine pulverization and before the molding. Preferably, the antioxidant in the second component is added after the coarse pulverization and before the fine pulverization and after the fine pulverization and before the molding.

[0028] In the present application, preferably, the first component further includes Co. The content of Co is preferably 0 to 2 mas% and not 0, more preferably 0 to 1.6 mas% and not 0, for example, 0.5 mas%, mas% being the mass percentage of each component with respect to the material for sintered magnet.

[0029] In the present application, preferably, the first component further includes Nb. The content of the Nb is preferably 0 to 0.4 mas%, and is not 0, for example, 0.1 mas%, mas% being the mass percentage of each component to the material for sintered magnet.

[0030] In the present application, preferably, the first component further includes Ti. The content of the Ti is preferably 0 to 0.4 mas%, and is not 0, for example, 0.18 mas%, mas% being the mass percentage of each component to the material for sintered magnet.

[0031] In the present application, preferably, the first component further includes Al. The content of the Al is preferably 0 to 0.5 mas%, and is not 0, for example, 0.3 mas%, mas% being the mass percentage of each component to the material for sintered magnet.

[0032] In the present application, the first component can further include one or more of Zr, Cr, Ta, Mo, W, V and Hf.

[0033] In the present application, preferably, the material for sintered magnet is composed of the following components in mass percentage: the first component is PrNd 29.5 to 33 mas%; Dy 0 to 2.5 mas%, and is not 0; B 0.95 mas% to 1 mas%; Cu 0.16 to 0.4 mas%; Ga 0.05 mas% to 0.25 mas%; Co 0.5 mas% to 1.6 mas%; Al 0.3 mas% to 0.5 mas%; the second component is ZrC or TiC 0.3 mas% to 0.5 mas%, and magnesium stearate 0.05 mas% to 0.15 mas%.

[0034] In the present application, preferably, the material for sintered magnet is composed of the following components in mass percentage: the first component is PrNd 29.5 to 33 mas%; B 0.86 mas% to 0.88 mas%; Cu 0.16 to 0.4 mas%; Ga 0.25 mas% to 0.5 mas%; Co 0.5 mas% to 1.6 mas%; the second component is ZrC or TiC 0.1 mas% to 0.5 mas%, and magnesium stearate 0.05 mas% to 0.15 mas%.

[0035] In the present application, preferably, the sintered magnet material is composed of the following components in mass percentage: the first component is Nd 29.5-33 mas%, Tb 0.1-0.5 mas%, B 0.95-1 mas%, Cu 0.16-0.4 mas%, Ga 0.05-0.25 mas%, Nb 0.1-0.4 mas%, Ti 0.18-0.4 mas%, the second component is WC, Cr3C2, TaC or NbC 0.1-0.5 mas%, and Mg stearate 0.05-0.15 mas%.

[0036] In the preferred embodiment of the present application, the sintered magnet material can be any one of the following Nos. 1-12 in mass percentage (mas%):

[0037]

[0038] The present application also provides a sintered magnet, which comprises the following components in mass percentage:

[0039] R: 29-33 mas%, the R being a rare earth element;

[0040] B: 0.86-1 mas%;

[0041] M: 0-0.5 mas% and not 0; the M comprising one or more of Ti, Zr, Cr, Nb, Ta, Mo, W, V and Hf;

[0042] Cu: 0-0.5 mas% and not 0;

[0043] Ga: 0-0.5 mas% and not 0;

[0044] Fe: 64-70 mas%;

[0045] C: 0.1-0.2 mas%;

[0046] mas% is the mass percentage of each component in the sintered magnet; the sintered magnet comprises NdFeB main phase grains, two-grain boundaries adjacent to the NdFeB main phase grains, and three-pronged grain boundaries, the three-pronged grain boundaries being distributed with fcc structure rare earth carbide; the surface of the NdFeB main phase grains is distributed with all or part of the M elements.

[0047] In the present application, the "surface of the NdFeB main phase crystal grains is distributed with all or part of the M elements" means that when all the M elements are derived from high-melting-point carbides, the surface of the NdFeB main phase crystal grains is distributed with all the M elements; when only part of the M elements are derived from high-melting-point carbides, the surface of the NdFeB main phase crystal grains is distributed with part of the M elements.

[0048] In the present application, the rare earth carbide refers to a compound formed by a rare earth element and C, which can be one or more of NdC, PrC, TbC and DyC according to the type of the added rare earth element.

[0049] In the present application, preferably, the content of R is 29.5 mas% to 32 mas%, for example, 29.6 mas% or 31 mas%, and mas% is the mass percentage of each component in the sintered magnet.

[0050] In the present application, preferably, R includes PrNd and / or Nd.

[0051] When R includes PrNd, the content of PrNd is preferably 0 to 33 mas% and not 0, for example, 29.5 mas%, and mas% is the mass percentage of each component in the sintered magnet.

[0052] When R includes Nd, the content of Nd is preferably 0 to 33 mas% and not 0, for example, 29.5 mas%, and mas% is the mass percentage of each component in the sintered magnet.

[0053] In the present application, preferably, R includes a heavy rare earth element RH. Preferably, the content of RH is 0 to 2.5 mas% and not 0, and mas% is the mass percentage of each component in the sintered magnet. Preferably, RH includes one or more of Tb, Dy, Ho and Gd. When RH includes Tb, the content of Tb is preferably 0 to 0.5 mas% and not 0, for example, 0.1 mas%, and mas% is the mass percentage of each component in the sintered magnet. When RH includes Dy, the content of Dy is preferably 0 to 2.5 mas% and not 0, and mas% is the mass percentage of each component in the sintered magnet.

[0054] In the present application, the content of B is preferably 0.86 mas% to 0.99 mas%, for example, 0.88 mas% or 0.95 mas%, and mas% is the mass percentage of each component in the sintered magnet.

[0055] In the present application, the content of Cu is preferably 0 to 0.4 mas%, and is not 0, for example, 0.16 mas% or 0.3 mas%, mas% being the mass percentage of each component with respect to the sintered magnet.

[0056] In the present application, the content of Ga is preferably 0.05 mas% to 0.5 mas%, for example, 0.25 mas%, mas% being the mass percentage of each component with respect to the sintered magnet.

[0057] In the present application, the content of Fe is preferably 64 mas% to 69 mas%, for example, 68.4 mas%, 66.4 mas% or 64.2 mas%, mas% being the mass percentage of each component with respect to the sintered magnet.

[0058] In the present application, the content of C is preferably 0.1 mas% to 0.16 mas%, for example, 0.155 mas%, 0.1178 mas%, 0.106 mas%, 0.111 mas%, 0.1105 mas%, 0.128 mas%, 0.153 mas%, 0.105 mas%, 0.124 mas%, 0.149 mas%, 0.124 mas% or 0.1475 mas%, mas% being the mass percentage of each component with respect to the sintered magnet.

[0059] In the present application, preferably, the sintered magnet further includes Al. The content of Al is preferably 0 to 0.5 mas%, and is not 0, for example, 0.3 mas%, mas% being the mass percentage of each component with respect to the sintered magnet.

[0060] In the present application, preferably, the sintered magnet further includes Co. The content of Co is preferably 0 to 2 mas%, and is not 0, more preferably, 0 to 1.6 mas%, and is not 0, for example, 0.5 mas%, mas% being the mass percentage of each component with respect to the sintered magnet.

[0061] In the present application, M preferably includes one or more of Ti, Nb, Zr, Cr and Ta.

[0062] When the sintered magnet includes Nb, the content of Nb is preferably 0 to 0.4 mas%, and is not 0, for example, 0.1 mas% or 0.32 mas%, mas% being the mass percentage of each component with respect to the sintered magnet.

[0063] When the sintered magnet includes Ti, the content of the Ti is preferably 0-0.4 mas% and not 0, for example 0.18 mas%, 0.15 mas%, 0.25 mas%, 0.3 mas% or 0.35 mas%, mas% being the mass percentage of each component in the sintered magnet.

[0064] When the sintered magnet includes Cr, the content of the Cr is preferably 0-0.4 mas% and not 0, for example 0.21 mas%, mas% being the mass percentage of each component in the sintered magnet.

[0065] When the sintered magnet includes W, the content of the W is preferably 0-0.4 mas% and not 0, for example 0.23 mas%, mas% being the mass percentage of each component in the sintered magnet.

[0066] When the sintered magnet includes Zr, the content of the Zr is preferably 0-0.5 mas% and not 0, for example 0.1 mas% or 0.3 mas%, mas% being the mass percentage of each component in the sintered magnet.

[0067] When the sintered magnet includes Ta, the content of the Ta is preferably 0-0.5 mas% and not 0, for example 0.23 mas%, mas% being the mass percentage of each component in the sintered magnet.

[0068] In the present application, the sintered magnet preferably consists of the following components in mass percentage: PrNd 29.5-33 mas%; Dy 0-2.5 mas% and not 0; B 0.95 mas%-1 mas%; Cu 0.16-0.4 mas%; Ga 0.05 mas%-0.25 mas%; Co 0.5 mas%-1.6 mas%; Al 0.3 mas%-0.5 mas%; Ti 0-0.4 mas% and not 0, C 0.1 mas%-0.16 mas%; the sintered magnet includes NdFeB main phase grains, two-grain boundaries adjacent to the NdFeB main phase grains and three-prong boundaries, the three-prong boundaries being distributed with fcc structure rare earth carbide; the surface of the NdFeB main phase grains is distributed with the Ti element.

[0069] In the present application, preferably, the sintered magnet is composed of the following components in mass percentage: PrNd 29.5-33 mas%; Dy 0-2.5 mas%, and not 0; B 0.95 mas%-1 mas%; Cu 0.16-0.4 mas%; Ga 0.05 mas%-0.25 mas%; Co 0.5 mas%-1.6 mas%; Al 0.3 mas%-0.5 mas%; Zr 0-0.4 mas%, and not 0, C 0.1 mas%-0.16 mas%; the sintered magnet comprises NdFeB main phase grains, two-grain boundaries adjacent to the NdFeB main phase grains, and three-pronged boundaries, the three-pronged boundaries are distributed with fcc structure rare earth carbide; the surface of the NdFeB main phase grains is distributed with the Zr element.

[0070] In the present application, preferably, the sintered magnet is composed of the following components in mass percentage: PrNd 29.5-33 mas%; B 0.86 mas%-0.88 mas%; Cu 0.16-0.4 mas%; Ga 0.25 mas%-0.5 mas%; Co 0.5 mas%-1.6 mas%; Ti 0-0.4 mas%, and not 0; the sintered magnet comprises NdFeB main phase grains, two-grain boundaries adjacent to the NdFeB main phase grains, and three-pronged boundaries, the three-pronged boundaries are distributed with fcc structure rare earth carbide; the surface of the NdFeB main phase grains is distributed with the Ti element.

[0071] In the present application, preferably, the sintered magnet is composed of the following components in mass percentage: PrNd 29.5-33 mas%; B 0.86 mas%-0.88 mas%; Cu 0.16-0.4 mas%; Ga 0.25 mas%-0.5 mas%; Co 0.5 mas%-1.6 mas%; Zr 0-0.5 mas%, and not 0; the sintered magnet comprises NdFeB main phase grains, two-grain boundaries adjacent to the NdFeB main phase grains, and three-pronged boundaries, the three-pronged boundaries are distributed with fcc structure rare earth carbide; the surface of the NdFeB main phase grains is distributed with the Zr element.

[0072] In the present application, preferably, the sintered magnet consists of the following components in mass percentage: Nd 29.5-33 mas%; Tb 0.1-0.5 mas%; B 0.95-1 mas%; Cu 0.16-0.4 mas%; Ga 0.05-0.25 mas%; Nb 0.32-0.4 mas%; Ti 0.18-0.4 mas%, and the sintered magnet comprises NdFeB main phase grains, two-grain boundaries adjacent to the NdFeB main phase grains, and three-prong boundaries, the three-prong boundaries are distributed with fcc structure rare earth carbide, and the surface of the NdFeB main phase grains is distributed with 0.22 mas% Nb element.

[0073] In the present application, preferably, the sintered magnet consists of the following components in mass percentage: Nd 29.5-33 mas%; Tb 0.1-0.5 mas%; B 0.95-1 mas%; Cu 0.16-0.4 mas%; Ga 0.05-0.25 mas%; Nb 0.1-0.4 mas%; Ti 0.18-0.4 mas%; Ta 0.23-0.5 mas% and not 0, and the sintered magnet comprises NdFeB main phase grains, two-grain boundaries adjacent to the NdFeB main phase grains, and three-prong boundaries, the three-prong boundaries are distributed with fcc structure rare earth carbide, and the surface of the NdFeB main phase grains is distributed with the Ta element.

[0074] In the present application, preferably, the sintered magnet consists of the following components in mass percentage: Nd 29.5-33 mas%; Tb 0.1-0.5 mas%; B 0.95-1 mas%; Cu 0.16-0.4 mas%; Ga 0.05-0.25 mas%; Nb 0.1-0.4 mas%; Ti 0.18-0.4 mas%; Cr 0.21-0.4 mas% and not 0, and the sintered magnet comprises NdFeB main phase grains, two-grain boundaries adjacent to the NdFeB main phase grains, and three-prong boundaries, the three-prong boundaries are distributed with fcc structure rare earth carbide, and the surface of the NdFeB main phase grains is distributed with the Cr element.

[0075] In the present application, preferably, the sintered magnet is composed of the following components in mass percentage: Nd 29.5-33 mas%; Tb 0.1-0.5 mas%; B 0.95-1 mas%; Cu 0.16-0.4 mas%; Ga 0.05-0.25 mas%; Nb 0.1-0.4 mas%; Ti 0.18-0.4 mas%; W 0.23-0.4 mas%, and not 0; the sintered magnet comprises NdFeB main phase grains, two-grain grain boundaries adjacent to the NdFeB main phase grains, and three-prong grain boundaries, the three-prong grain boundaries are distributed with fcc-structured rare earth carbides; the surface of the NdFeB main phase grains is distributed with the W element.

[0076] In the preferred embodiment of the present application, the kind and amount of the sintered magnet can be any of the following numbers 1-12 (mas%):

[0077]

[0078] The present application also provides a rare earth permanent magnet comprising the following components in mass percentage:

[0079] R: 29-33 mas%, the R being a rare earth element;

[0080] B: 0.86-1 mas%;

[0081] M: 0-0.5 mas%, and not 0; the M comprising one or more of Ti, Zr, Cr, Nb, Ta, Mo, W, V, and Hf;

[0082] Cu: 0-0.5 mas%, and not 0;

[0083] Ga: 0-0.5 mas%, and not 0;

[0084] Fe: 64-70 mas%;

[0085] C: 0.1-0.2 mas%;

[0086] mas% is the mass percentage of each component in the rare earth permanent magnet;

[0087] The rare earth permanent magnet comprises NdFeB main phase grains, two-grain grain boundaries adjacent to the NdFeB main phase grains, and three-prong grain boundaries, the three-prong grain boundaries are distributed with hcp-structured rare earth carbides; the two-grain grain boundaries are distributed with RE-Cu-Fe-C-Ga phase;

[0088] The surface of the NdFeB main phase grains is distributed with all or part of the M element.

[0089] In the present application, the phrase "the surface of the NdFeB main phase crystal grain is distributed with all or part of the M element" means that when all the M element is derived from high melting point carbide, the surface of the NdFeB main phase crystal grain is distributed with all the M element; when only part of the M element is derived from high melting point carbide, the surface of the NdFeB main phase crystal grain is distributed with part of the M element.

[0090] In the present application, the phrase "triple junction" generally refers to the place where three or more grain boundaries intersect.

[0091] In the present application, the phrase "rare earth carbide" refers to a compound formed by a rare earth element and C, which can be one or more of NdC, PrC, TbC and DyC according to the type of added rare earth element.

[0092] In the present application, preferably, the triple junction is also distributed with Nd6(FeGa) 14 .

[0093] In the present application, preferably, the content of R is 29.5 mas% to 32 mas%, for example, 29.6 mas% or 31 mas%, and mas% is the mass percentage of each component in the rare earth permanent magnet.

[0094] In the present application, preferably, R includes PrNd and / or Nd.

[0095] When R includes PrNd, the content of PrNd is preferably 0 to 33 mas% and not 0, for example, 29.5 mas% or 31 mas%, and mas% is the mass percentage of each component in the rare earth permanent magnet.

[0096] When R includes Nd, the content of Nd is preferably 0 to 33 mas% and not 0, for example, 29.5 mas%, and mas% is the mass percentage of each component in the rare earth permanent magnet.

[0097] In the present application, preferably, R includes heavy rare earth element RH. Preferably, the content of RH is 0 to 2.5 mas% and not 0, and mas% is the mass percentage of each component in the rare earth permanent magnet. Preferably, RH includes one or more of Tb, Dy, Ho and Gd. When RH includes Tb, the content of Tb is preferably 0 to 0.5 mas% and not 0, for example, 0.1 mas%, and mas% is the mass percentage of each component in the rare earth permanent magnet. When RH includes Dy, the content of Dy is preferably 0 to 2.5 mas% and not 0, and mas% is the mass percentage of each component in the rare earth permanent magnet.

[0098] In the present application, the content of B is preferably 0.86 mas% to 0.99 mas%, for example 0.88 mas% or 0.95 mas%, mas% being the mass percentage of each component in the rare earth permanent magnet.

[0099] In the present application, the content of Cu is preferably 0 to 0.4 mas% and not 0, for example 0.16 mas% or 0.3 mas%, mas% being the mass percentage of each component in the rare earth permanent magnet.

[0100] In the present application, the content of Ga is preferably 0.05 mas% to 0.5 mas%, for example 0.25 mas%, mas% being the mass percentage of each component in the rare earth permanent magnet.

[0101] In the present application, the content of Fe is preferably 64 mas% to 69 mas%, for example 68.4 mas%, 66.4 mas% or 64.2 mas%, mas% being the mass percentage of each component in the rare earth permanent magnet.

[0102] In the present application, the content of C is preferably 0.1 mas% to 0.16 mas%, for example 0.155 mas%, 0.1178 mas%, 0.106 mas%, 0.111 mas%, 0.1105 mas%, 0.128 mas%, 0.153 mas%, 0.105 mas%, 0.124 mas%, 0.149 mas%, 0.124 mas% or 0.1475 mas%, mas% being the mass percentage of each component in the rare earth permanent magnet.

[0103] In the present application, preferably, the rare earth permanent magnet further comprises Al. The content of Al is preferably 0 to 0.5 mas% and not 0, for example 0.3 mas%, mas% being the mass percentage of each component in the rare earth permanent magnet.

[0104] In the present application, preferably, the rare earth permanent magnet further comprises Co. The content of Co is preferably 0 to 2 mas% and not 0, more preferably 0 to 1.6 mas% and not 0, for example 0.5 mas%, mas% being the mass percentage of each component in the rare earth permanent magnet.

[0105] In the present application, M preferably comprises one or more of Ti, Nb, Zr, Cr and Ta.

[0106] When the rare earth permanent magnet comprises Nb, the content of Nb is preferably 0 to 0.4 mas% and not 0, for example 0.1 mas% or 0.32 mas%, mas% being the mass percentage of each component in the rare earth permanent magnet.

[0107] When the rare earth permanent magnet comprises Ti, the content of the Ti is preferably 0-0.4 mas%, and is not 0, for example 0.18 mas%, 0.15 mas%, 0.25 mas%, 0.3 mas% or 0.35 mas%, mas% being the mass percentage of each component in the rare earth permanent magnet.

[0108] When the rare earth permanent magnet comprises Cr, the content of the Cr is preferably 0-0.4 mas%, and is not 0, for example 0.21 mas%, mas% being the mass percentage of each component in the rare earth permanent magnet.

[0109] When the rare earth permanent magnet comprises W, the content of the W is preferably 0-0.4 mas%, and is not 0, for example 0.23 mas%, mas% being the mass percentage of each component in the rare earth permanent magnet.

[0110] When the rare earth permanent magnet comprises Zr, the content of the Zr is preferably 0-0.5 mas%, and is not 0, for example 0.1 mas% or 0.3 mas%, mas% being the mass percentage of each component in the rare earth permanent magnet.

[0111] When the rare earth permanent magnet comprises Ta, the content of the Ta is preferably 0-0.5 mas%, and is not 0, for example 0.23 mas%, mas% being the mass percentage of each component in the rare earth permanent magnet.

[0112] In the present application, preferably, the rare earth permanent magnet consists of the following components in mass percentage: PrNd 29.5-33 mas%; Dy 0-2.5 mas%, and is not 0; B 0.95 mas%-1 mas%; Cu 0.16-0.4 mas%; Ga 0.05 mas%-0.25 mas%; Co 0.5 mas%-1.6 mas%; Al 0.3 mas%-0.5 mas%; Ti 0-0.4 mas%, and is not 0, C 0.1 mas%-0.16 mas%; the rare earth permanent magnet comprises NdFeB main phase grains, two-grain boundaries adjacent to the NdFeB main phase grains and three-prong boundaries, the three-prong boundaries are distributed with hcp structure rare earth carbide; the two-grain boundaries are distributed with RE-Cu-Fe-C-Ga phase; the surface of the NdFeB main phase grains is distributed with the Ti element.

[0113] In the application, preferably, the rare earth permanent magnet consists of the following components in percentage of mass: PrNd 29.5-33 mas%; Dy 0-2.5 mas% and not 0; B 0.95 mas%-1 mas%; Cu 0.16-0.4 mas%; Ga 0.05 mas%-0.25 mas%; Co 0.5 mas%-1.6 mas%; Al 0.3 mas%-0.5 mas%; Zr 0-0.4 mas% and not 0, C 0.1 mas%-0.16 mas%; the rare earth permanent magnet comprises NdFeB main phase grains, two-particle grain boundaries adjacent to the NdFeB main phase grains and three-prong grain boundaries, the three-prong grain boundaries are distributed with hcp structure rare earth carbide; the two-particle grain boundaries are distributed with RE-Cu-Fe-C-Ga phase; the surface of the NdFeB main phase grains is distributed with the Zr element.

[0114] In the application, preferably, the rare earth permanent magnet consists of the following components in percentage of mass: PrNd 29.5-33 mas%; B 0.86 mas%-0.88 mas%; Cu 0.16-0.4 mas%; Ga 0.25 mas%-0.5 mas%; Co 0.5 mas%-1.6 mas%; Ti 0-0.4 mas% and not 0; the rare earth permanent magnet comprises NdFeB main phase grains, two-particle grain boundaries adjacent to the NdFeB main phase grains and three-prong grain boundaries, the three-prong grain boundaries are distributed with hcp structure rare earth carbide; the two-particle grain boundaries are distributed with RE-Cu-Fe-C-Ga phase; the surface of the NdFeB main phase grains is distributed with the Ti element.

[0115] In the application, preferably, the rare earth permanent magnet consists of the following components in percentage of mass: PrNd 29.5-33 mas%; B 0.86 mas%-0.88 mas%; Cu 0.16-0.4 mas%; Ga 0.25 mas%-0.5 mas%; Co 0.5 mas%-1.6 mas%; Zr 0-0.5 mas% and not 0; the rare earth permanent magnet comprises NdFeB main phase grains, two-particle grain boundaries adjacent to the NdFeB main phase grains and three-prong grain boundaries, the three-prong grain boundaries are distributed with hcp structure rare earth carbide; the two-particle grain boundaries are distributed with RE-Cu-Fe-C-Ga phase; the surface of the NdFeB main phase grains is distributed with the Zr element.

[0116] In the application, preferably, the rare earth permanent magnet consists of the following components in percentage of mass: Nd 29.5-33 mas%; Tb 0.1-0.5 mas%; B 0.95-1 mas%; Cu 0.16-0.4 mas%; Ga 0.05-0.25 mas%; Nb 0.32-0.4 mas%; Ti 0.18-0.4 mas%, the rare earth permanent magnet comprises NdFeB main phase crystal grains, two-particle grain boundaries adjacent to the NdFeB main phase crystal grains and three-prong grain boundaries, the three-prong grain boundaries are distributed with hcp structure rare earth carbide; the two-particle grain boundaries are distributed with RE-Cu-Fe-C-Ga phase; the surface of the NdFeB main phase crystal grains is distributed with 0.22 mas% Nb element.

[0117] In the application, preferably, the rare earth permanent magnet consists of the following components in percentage of mass: Nd 29.5-33 mas%; Tb 0.1-0.5 mas%; B 0.95-1 mas%; Cu 0.16-0.4 mas%; Ga 0.05-0.25 mas%; Nb 0.1-0.4 mas%; Ti 0.18-0.4 mas%; Ta 0.23-0.5 mas% and not 0, the rare earth permanent magnet comprises NdFeB main phase crystal grains, two-particle grain boundaries adjacent to the NdFeB main phase crystal grains and three-prong grain boundaries, the three-prong grain boundaries are distributed with hcp structure rare earth carbide; the two-particle grain boundaries are distributed with RE-Cu-Fe-C-Ga phase; the surface of the NdFeB main phase crystal grains is distributed with the Ta element.

[0118] In the application, preferably, the rare earth permanent magnet consists of the following components in percentage of mass: Nd 29.5-33 mas%; Tb 0.1-0.5 mas%; B 0.95-1 mas%; Cu 0.16-0.4 mas%; Ga 0.05-0.25 mas%; Nb 0.1-0.4 mas%; Ti 0.18-0.4 mas%; Cr 0.21-0.4 mas% and not 0, the rare earth permanent magnet comprises NdFeB main phase crystal grains, two-particle grain boundaries adjacent to the NdFeB main phase crystal grains and three-prong grain boundaries, the three-prong grain boundaries are distributed with hcp structure rare earth carbide; the two-particle grain boundaries are distributed with RE-Cu-Fe-C-Ga phase; the surface of the NdFeB main phase crystal grains is distributed with the Cr element.

[0119] In the present application, preferably, the rare earth permanent magnet is composed of the following components in mass percentage: Nd 29.5-33 mas%; Tb 0.1 mas%-0.5 mas%; B 0.95 mas%-1 mas%; Cu 0.16-0.4 mas%; Ga 0.05 mas%-0.25 mas%; Nb 0.1 mas%-0.4 mas%; Ti 0.18 mas%-0.4 mas%; and W 0.23-0.4 mas%, and not 0. The rare earth permanent magnet comprises NdFeB main phase grains, two-particle grain boundaries adjoining the NdFeB main phase grains, and three-prong grain boundaries, wherein the three-prong grain boundaries are distributed with hcp structure rare earth carbide; the two-particle grain boundaries are distributed with RE-Cu-Fe-C-Ga phase; and the surface of the NdFeB main phase grains is distributed with the element W.

[0120] In the preferred embodiment of the present application, the type and amount of the rare earth permanent magnet can be any of the following numbers 1-12 (mas%):

[0121]

[0122]

[0123] The present application also provides a preparation method of sintered magnet, which comprises the following steps: melting the first component in the sintered magnet material, and coarsely crushing to obtain coarse powder;

[0124] finely crushing the mixture of the coarse powder and the antioxidant in an amount of 40%-60% to obtain fine powder;

[0125] molding and sintering the mixture of the fine powder and the remaining second component.

[0126] In the present application, the "antioxidant in an amount of 40%-60%" refers to the antioxidant added before fine crushing, which accounts for 40%-60% of the total amount of antioxidant.

[0127] In the present application, the melting temperature can be 1300-1700°C, for example, 1500°C.

[0128] In the present application, the melting equipment is generally high-frequency vacuum melting furnace and / or medium-frequency vacuum melting furnace. The medium-frequency vacuum melting furnace can be a medium-frequency vacuum induction rapid solidification strip casting furnace.

[0129] In the present application, the operation and conditions of melting can be the conventional melting process in the art, which generally adopts ingot casting process or rapid solidification sheet process to melt and cast each element of the first component to obtain alloy sheet.

[0130] The person skilled in the art knows that, in order to ensure the quality of the final product, 0-0.3 mas% of rare earth elements (generally Nd elements) are usually additionally added in the formula of the raw material composition during the smelting process, and the percentage is the content of the additional rare earth elements in the mass percentage of the material for sintered magnet; in addition, the content of the additional rare earth elements is not included in the category of the raw material composition.

[0131] In the present application, the coarse crushing can be hydrogen crushing. The hydrogen crushing generally includes hydrogen absorption, hydrogen desorption and cooling treatment. The temperature of hydrogen absorption is generally 20-200℃, preferably 20-40℃ (i.e. room temperature). The pressure of hydrogen absorption is generally 50-600kPa, for example 90kPa. The temperature of hydrogen desorption is generally 400-650℃, for example 550℃.

[0132] In the present application, the fine crushing can be jet milling. The gas flow in the jet milling can be, for example, nitrogen and / or argon. The pressure of the jet milling is generally 0.1-2MPa, preferably 0.5-0.7MPa, for example 0.65MPa. The efficiency of the jet milling can vary depending on the equipment, for example, it can be 30-400kg / h, preferably 200kg / h.

[0133] In the present application, the forming operation and conditions can be conventional forming processes in the art, for example, magnetic field forming method. The magnetic field strength of the magnetic field forming method is generally above 1.5T.

[0134] In the present application, the sintering operation and conditions can be conventional sintering processes in the art, for example, vacuum sintering process and / or inert atmosphere sintering process. Both the vacuum sintering process and the inert atmosphere sintering process are conventional operations in the art. When the inert atmosphere sintering process is used, the initial stage of sintering can be carried out under the condition that the vacuum degree is less than 0.5Pa. The inert atmosphere can be conventional atmosphere containing inert gas in the art, not limited to helium and argon, and can also be nitrogen.

[0135] In the present application, the sintering temperature can be 1000-1200℃, preferably 1030-1090℃.

[0136] In the present application, the sintering time can be 0.5-10h, preferably 2-8h.

[0137] The present application also provides a sintered magnet prepared by the preparation method of sintered magnet.

[0138] The present application also provides a preparation method of rare earth permanent magnet, which comprises the following steps: preparing the above-mentioned sintered magnet by one of the following two methods:

[0139] Method one: sequentially through a primary aging treatment and a secondary aging treatment;

[0140] Method two: sequentially through a grain boundary diffusion treatment and a secondary aging treatment.

[0141] In the present application, the heavy rare earth element in the grain boundary diffusion treatment preferably comprises Tb and / or Dy.

[0142] In the present application, the grain boundary diffusion treatment can be processed according to the conventional process in the art, for example, a substance containing Tb or a substance containing Dy is attached on the surface of the sintered magnet by evaporation, coating or sputtering, and then a diffusion heat treatment is performed.

[0143] The substance containing Tb or Dy can be Tb or Dy metal, a compound or an alloy containing Tb or Dy.

[0144] The temperature of the grain boundary diffusion treatment can be 800-900℃, for example 850℃.

[0145] The time of the grain boundary diffusion treatment can be 12-48h, for example 24h.

[0146] In the present application, the temperature of the primary aging treatment is preferably 880-920℃, for example 900℃.

[0147] The time of the primary aging treatment is preferably 2-4h, for example 2h.

[0148] In the present application, the temperature of the secondary aging treatment is preferably 460-520℃, for example 490℃.

[0149] The time of the secondary aging treatment is preferably 2-4h, for example 2h.

[0150] The present application also provides a rare earth permanent magnet prepared by the above preparation method.

[0151] The present application also provides a sintered magnet and / or a rare earth permanent magnet as a rotor of a permanent magnet motor.

[0152] On the basis of common sense in the art, the above preferred conditions can be combined arbitrarily, i.e. to obtain each preferred example of the present application.

[0153] The reagents and raw materials used in the present application are commercially available.

[0154] The positive progress effect of the present application is that:

[0155] (1) the coercivity of the rare earth permanent magnet under low B is above 15.8kOe, while maintaining a high remanence;

[0156] (2) In the preferred embodiment of the present application, the coercive force of the rare earth permanent magnet is above 25.6 kOe, while maintaining a high remanence. BRIEF DESCRIPTION OF DRAWINGS

[0157] Figure 1 EPMA distribution of each element in Example 2. DETAILED DESCRIPTION

[0158] The present application will be further described by way of examples, but the present application is not limited to the examples. In the following examples, the experimental methods not specified in the examples are selected according to the conventional methods and conditions, or according to the instructions of the commercial products.

[0159] Table 1 Formulation and amount (mas%) of materials for sintered magnets

[0160]

[0161]

[0162] Note: " / " in the above table means that the element is not contained

[0163] Examples 1 to 4 and Comparative Examples 1 to 3

[0164] The antioxidant used in the following examples and comparative examples is magnesium stearate;

[0165] (1) Melting process: The first component raw materials prepared according to the formulation in Table 1 are vacuum melted at 1500°C in a high frequency vacuum melting furnace, and then cast in an intermediate frequency vacuum induction rapid solidification spinning furnace with argon gas, to obtain alloy pieces.

[0166] (2) Coarse crushing process: The alloy pieces are placed in a hydrogen breaking furnace, and the hydrogen breaking furnace is vacuumed at room temperature, and then pure hydrogen gas with a purity of 99.9% is introduced into the hydrogen breaking furnace, and the pressure of the hydrogen gas is maintained at 90 kPa. After sufficient hydrogen absorption, the hydrogen is removed while the temperature is raised, and the hydrogen is fully removed, and then cooled to obtain coarse powder. The hydrogen absorption temperature is room temperature, and the hydrogen removal temperature is 550°C.

[0167] (3) Fine crushing process: The mixture of the coarse powder and 50% of the total amount of magnesium stearate (see Table 1) is placed in a jet mill tank, and the mixture is jet milled in a nitrogen atmosphere at a crushing chamber pressure of 0.65 MPa (the efficiency of the jet mill may vary depending on the equipment, for example, it can be 200 kg / h) to obtain fine powder.

[0168] (4) Molding Process: The fine powder was mixed with the remaining second component of Table 1 and molded under a magnetic field strength of 1.5T or more to obtain a molded body.

[0169] (5) Sintering Process: Each molded body was moved to a sintering furnace and sintered under a vacuum of 0.5Pa or less at 1030-1090°C for 8h to obtain a sintered magnet.

[0170] (6) Grain Boundary Diffusion and Aging Process: After the surface of the sintered magnet was cleaned, a Tb alloy containing 0.4mas% Tb was coated on the surface of the sintered magnet and diffused at a temperature of 850°C for 24h, and then cooled to room temperature, and then vacuum heat treated at 490°C for 2h to obtain a rare earth permanent magnet.

[0171] Examples 5-12 and Comparative Examples 4-5

[0172] The only difference between the preparation method of Examples 1-4 and Comparative Example 1 is that step (6) is as follows:

[0173] (6) Aging Process: The sintered magnet was vacuum heat treated at 900°C for 2h, and then vacuum heat treated at 490°C for 2h to obtain a rare earth permanent magnet.

[0174] Effect Examples

[0175] The sintered magnets and rare earth permanent magnets of Examples 1-12 and Comparative Examples 1-3 were taken separately, and their magnetic properties and components were measured, and the phase composition of the magnets was observed using EPMA-1720.

[0176] (1) The components of the sintered magnets and rare earth permanent magnets of Examples 1-12 and Comparative Examples 1-4 were measured using a high-frequency inductively coupled plasma emission spectrometer (ICP-OES, Icap6300); the component measurement results are shown in Tables 2 and 3 below. The grain boundary structure was detected using EPMA-1720, and the rare earth carbide distribution in Table 2 and Table 3 is in the three-pronged grain boundary, and the R-Fe-Cu-C-Ga distribution is in the two-particle grain boundary.

[0177] Table 2 Formulation of Sintered Magnet (mas%)

[0178]

[0179] Note: " / " in the above table means that the element is not contained; "0.23W" in the column of "elements distributed on the surface of the main phase grain" means that the content of W is 0.23mas%, i.e., 0.23mas% of W is distributed on the surface of the main phase grain.

[0180] Table 3 Formulation of Rare Earth Permanent Magnet (mas%)

[0181]

[0182]

[0183] Note: " / " in the above table means not containing the element; "0.23W" in the column of "element distributed on the surface of the main phase crystal grain" means that the content of W is 0.23 mas%, i.e. 0.23 mas% of W is distributed on the surface of the main phase crystal grain.

[0184] (2) Evaluation of magnetic properties: The sintered magnet and the rare earth permanent magnet were detected for magnetic properties by using PFM-14 magnetic property measuring instrument of Hirst Company in England; the results of the detection of magnetic properties are shown in Table 4 below.

[0185] From Examples 1-4 and Comparative Example 1 in Table 4, it can be seen that the Br of the sintered magnet of the present application is all above 14.25 kGs, while the coercivity is also maintained above 11.51 kOe; the coercivity of the rare earth permanent magnet after the grain boundary diffusion and the secondary aging treatment is all above 23.5 kOe, which shows that the sintered magnet of the present application can still maintain good magnetic properties under the premise of higher carbon content;

[0186] From Examples 2 and Comparative Example 3, it can be seen that under the premise of not containing Cu, the remanence and coercivity of the sintered magnet and the rare earth permanent magnet are all decreased.

[0187] From Examples 2 and Comparative Example 2, it can be seen that under the premise of increasing the carbon content by increasing the amount of antioxidant, the remanence and coercivity of the sintered magnet and the rare earth permanent magnet are all decreased.

[0188] From Examples 5-10 and Comparative Example 4, it can be seen that the coercivity of the rare earth permanent magnet at low B is all above 15.8 kOe, while maintaining a high remanence.

[0189] From Examples 11-12 and Comparative Example 5, it can be seen that the coercivity of the sintered magnet is all above 25.6 kOe, while maintaining a high remanence.

[0190] Table 4 Magnetic properties

[0191]

[0192] Note: " / " in the above table means not containing the element; the rare earth permanent magnets of Examples 1-4 and Comparative Examples 1-3 are treated by diffusion and secondary aging, and the rare earth permanent magnets of Examples 5-12 and Comparative Examples 4, 5 are treated by primary and secondary aging.

[0193] (3) Measurement of microstructure: The rare earth permanent magnet of Example 2 was tested by EPMA-1720 (as shown in Table 5 below), and the results are shown in Table 6 below. Figure 1 Figure 1 ​It can be seen that the distribution of Cr and C is completely different, which indicates that CrC has been decomposed. According to the distribution of C, it can be seen that C and rare earth are distributed in the grain boundary, and mainly in the triple junction. However, for Cr, it is distributed on the surface of NdFeB main phase grains.

Claims

1. A sintered magnet, characterized by, The raw material thereof comprises a first component and a second component, the first component comprises, in mass percentage: R: 29mas%~33mas%, the R being a rare earth element; B: 0.86mas%~1mas%; Cu: 0~0.5mas%, and not 0; Ga: 0~0.5mas%, and not 0; Fe: 64mas%~70mas%; The second component comprises an antioxidant and a high-melting-point carbide, the high-melting-point carbide comprising one or more of titanium carbide, zirconium carbide, chromium carbide, niobium carbide, tantalum carbide and tungsten carbide; the content of the high-melting-point carbide being 0.2~0.5mas%, the content of the antioxidant being 0.05mas%~0.15mas%; mas% being the mass percentage of each component in the sintered magnet; the sintered magnet comprising NdFeB main phase grains, two-grain boundaries adjacent to the NdFeB main phase grains and three-pronged grain boundaries, the three-pronged grain boundaries being distributed with fcc structure rare earth carbide; the surface of the NdFeB main phase grains being distributed with all or part of M elements, the M elements being one or more of the metal elements in the high-melting-point carbide.

2. The sintered magnet according to claim 1, wherein The content of the R is 29.5mas%~32mas%, mas% being the mass percentage of each component in the sintered magnet; And / or, the R comprises PrNd and / or Nd; And / or, the R comprises heavy rare earth elements RH; And / or, the content of the B is 0.86mas%~0.99mas%, mas% being the mass percentage of each component in the sintered magnet; And / or, the content of the Cu is 0~0.4mas%, and not 0, mas% being the mass percentage of each component in the sintered magnet; And / or, the content of the Ga is 0.05mas%~0.5mas%, mas% being the mass percentage of each component in the sintered magnet; And / or, the content of the Fe is 64.5mas%~69mas%, mas% being the mass percentage of each component in the sintered magnet; And / or, the antioxidant is magnesium stearate and / or tributyl borate; And / or, the first component further comprises Co; And / or, the first component further comprises Nb; And / or, the first component further comprises Ti; And / or; the first component further comprises Al; And / or, the first component further comprises one or more of Zr, Cr, Ta, Mo, W, V and Hf.

3. The sintered magnet according to claim 1, wherein The raw material of the sintered magnet, in mass percentage, is composed of the following components: the first component is PrNd 29.5~32mas%; Dy 0~2.5mas%, and not 0; B 0.95mas%~1mas%; Cu 0.16~0.4mas%; Ga 0.05mas%~0.25mas%; Co 0.5mas%~1.6mas%; Al 0.3mas%~0.5mas%; the second component is ZrC or TiC 0.3mas%~0.5mas%, magnesium stearate 0.05mas%-0.15mas%; Or, the raw material of the sintered magnet consists of the following components in mass percentage: the first component is PrNd 29.5-33 mas%; B 0.86 mas%-0.88 mas%; Cu 0.16-0.4 mas%; Ga 0.25 mas%-0.5 mas%; Co 0.5 mas%-1.6 mas%; the second component is ZrC or TiC 0.1 mas%-0.5 mas%, magnesium stearate 0.05 mas%-0.15 mas%; And / or, the raw material of the sintered magnet consists of the following components in mass percentage: the first component is Nd 29.5-32 mas%; Tb 0.1 mas%-0.5 mas%; B 0.95 mas%-1 mas%; Cu 0.16-0.4 mas%; Ga 0.05 mas%-0.25 mas%; Nb 0.1 mas%-0.4 mas%, Ti 0.18 mas%-0.4 mas%, the second component is WC, Cr3C2, TaC or NbC 0.1 mas%-0.5 mas%, magnesium stearate 0.05 mas%-0.15 mas%.

4. The sintered magnet according to claim 1, wherein The content of R is 29.6 mas% or 31 mas%, and mas% is the mass percentage of each component in the sintered magnet.

5. The sintered magnet according to claim 1, wherein The R includes PrNd, the content of PrNd is 0-33 mas% and not 0, and mas% is the mass percentage of each component in the sintered magnet.

6. The sintered magnet according to claim 1, wherein The R includes Nd, the content of Nd is 0-33 mas% and not 0, and mas% is the mass percentage of each component in the sintered magnet.

7. The sintered magnet according to claim 1, wherein The R includes heavy rare earth elements RH, the content of RH is 0-2.5 mas% and not 0, and mas% is the mass percentage of each component in the sintered magnet; And / or, the R includes heavy rare earth elements RH, the RH includes one or more of Tb, Dy, Ho and Gd; And / or, the content of B is 0.88 mas% or 0.95 mas%, and mas% is the mass percentage of each component in the sintered magnet; And / or, the content of Cu is 0.16 mas% or 0.3 mas%, and mas% is the mass percentage of each component in the sintered magnet; And / or, the content of Ga is 0.25 mas%, and mas% is the mass percentage of each component in the sintered magnet; And / or, the content of Fe is 68.78 mas%, 66.72 mas% or 64.74 mas%, and mas% is the mass percentage of each component in the sintered magnet; And / or, the first component further includes Co, the content of Co is 0-2 mas% and not 0, and mas% is the mass percentage of each component in the sintered magnet; And / or, the first component further includes Nb, the content of Nb is 0-0.4 mas% and not 0, and mas% is the mass percentage of each component in the sintered magnet; And / or, the first component further comprises Ti, the content of the Ti being 0~0.4 mas%, and not being 0, mas% being the mass percentage of each component in the sintered magnet; And / or, the first component further comprises Al, the content of the Al being 0~0.5 mas%, and not being 0, mas% being the mass percentage of each component in the sintered magnet.

8. The sintered magnet according to claim 1, wherein The R comprises PrNd, the content of the PrNd being 29.5 mas% or 31 mas%, mas% being the mass percentage of each component in the sintered magnet.

9. The sintered magnet according to claim 1, wherein The R comprises Nd, the content of the Nd being 29.5 mas%, mas% being the mass percentage of each component in the sintered magnet.

10. The sintered magnet according to claim 1, wherein The R comprises heavy rare earth elements RH, the RH comprising Tb, the content of the Tb being 0~0.5 mas%, and not being 0, mas% being the mass percentage of each component in the sintered magnet; And / or, the R comprises heavy rare earth elements RH, the RH comprising Dy, the content of the Dy being 0~2.5 mas%, and not being 0, mas% being the mass percentage of each component in the sintered magnet; And / or, the first component further comprises Co, the content of the Co being 0~1.6 mas%, and not being 0, mas% being the mass percentage of each component in the sintered magnet; And / or, the first component further comprises Nb, the content of the Nb being 0.1 mas%, mas% being the mass percentage of each component in the sintered magnet; And / or, the first component further comprises Ti, the content of the Ti being 0.18 mas%, mas% being the mass percentage of each component in the sintered magnet; And / or, the first component further comprises Al, the content of the Al being 0.3 mas%, mas% being the mass percentage of each component in the sintered magnet.

11. The sintered magnet according to claim 1, wherein The R comprises heavy rare earth elements RH, the RH comprising Tb, the content of the Tb being 0.1 mas%, mas% being the mass percentage of each component in the sintered magnet; And / or, the first component further comprises Co, the content of the Co being 0.5 mas%.

12. A sintered magnet, characterized by comprising: In mass percentage, it comprises the following components: R: 29 mas%~33 mas%, the R being rare earth elements; B: 0.86 mas%~1 mas%; M: 0~0.5 mas%, and not being 0; the M comprising one or more of Ti, Nb, Zr, Cr and Ta; Cu: 0~0.5 mas%, and not being 0; Ga: 0~0.5 mas%, and not being 0; Fe: 64 mas%~70 mas%; C: 0.1~0.2 mas%; Mas% being the mass percentage of each component in the sintered magnet; the sintered magnet comprising NdFeB main phase grains, two-grain boundaries adjacent to the NdFeB main phase grains and three-pronged grain boundaries, the three-pronged grain boundaries being distributed with fcc structure rare earth carbides; the surface of the NdFeB main phase grains being distributed with all or part of the elements of the M.

13. The sintered magnet according to claim 12, wherein The rare earth carbides are one or more of NdC, PrC, TbC and DyC; And / or, the content of R is 29.5mas%~32mas%, mas% is the mass percentage of each component in the sintered magnet; And / or, the R includes PrNd and / or Nd; And / or, the R includes heavy rare earth elements RH; And / or, the content of B is 0.86mas%~0.99mas%, mas% is the mass percentage of each component in the sintered magnet; And / or, the content of Cu is 0~0.4mas%, and not 0, mas% is the mass percentage of each component in the sintered magnet; And / or, the content of Ga is 0.05mas%~0.5mas%, mas% is the mass percentage of each component in the sintered magnet; And / or, the content of Fe is 64mas%~69mas%, mas% is the mass percentage of each component in the sintered magnet; And / or, the content of C is 0.1mas%~0.16mas%, mas% is the mass percentage of each component in the sintered magnet; And / or, the sintered magnet further includes Al; And / or, the sintered magnet further includes Co.

14. The sintered magnet according to claim 12, wherein The sintered magnet is composed of the following components in mass percentage: PrNd 29.5~32mas%; Dy 0~2.5mas%, and not 0; B 0.95mas%~1mas%; Cu 0.16~0.4mas%; Ga 0.05mas%~0.25mas%; Co 0.5mas%~1.6mas%; Al 0.3mas%~0.5mas%; Ti 0~0.4mas%, and not 0, C 0.1mas%~0.16mas%; the surface of the NdFeB main phase grain is distributed with the Ti; Or, the sintered magnet is composed of the following components in mass percentage: PrNd 29.5~32mas%; Dy 0~2.5mas%, and not 0; B 0.95mas%~1mas%; Cu 0.16~0.4mas%; Ga 0.05mas%~0.25mas%; Co 0.5mas%~1.6mas%; Al 0.3mas%~0.5mas%; Zr 0~0.4mas%, and not 0, C 0.1mas%~0.16mas%; the surface of the NdFeB main phase grain is distributed with the Zr; Or, the sintered magnet is composed of the following components in mass percentage: PrNd 29.5~33mas%; B 0.86mas%~0.88mas%; Cu 0.16~0.4mas%; Ga 0.25mas%~0.5mas%; Co 0.5mas%~1.6mas%; Ti 0~0.4mas%, and not 0; the surface of the NdFeB main phase grain is distributed with the Ti; Or, the sintered magnet is composed of the following components in mass percentage: PrNd 29.5~33 mas%; B 0.86 mas%~0.88 mas%; Cu 0.16~0.4 mas%; Ga 0.25 mas%~0.5 mas%; Co 0.5 mas%~1.6 mas%; Zr 0~0.5 mas%, and not 0; the surface of the NdFeB main phase grains is distributed with the Zr; Or, the sintered magnet is composed of the following components in mass percentage: Nd 29.5~32 mas%; Tb 0.1 mas%~0.5 mas%; B 0.95 mas%~1 mas%; Cu 0.16~0.4 mas%; Ga 0.05 mas%~0.25 mas%; Nb 0.32 mas%~0.4 mas%, Ti 0.18 mas%~0.4 mas%, the surface of the NdFeB main phase grains is distributed with 0.22 mas% Nb element; Or, the sintered magnet is composed of the following components in mass percentage: Nd 29.5~32 mas%; Tb 0.1 mas%~0.5 mas%; B 0.95 mas%~1 mas%; Cu 0.16~0.4 mas%; Ga 0.05 mas%~0.25 mas%; Nb 0.1 mas%~0.4 mas%, Ti 0.18 mas%~0.4 mas%; Ta 0.23~0.5 mas%, and not 0; the surface of the NdFeB main phase grains is distributed with the Ta; Or, the sintered magnet is composed of the following components in mass percentage: Nd 29.5~32 mas%; Tb 0.1 mas%~0.5 mas%; B 0.95 mas%~1 mas%; Cu 0.16~0.4 mas%; Ga 0.05 mas%~0.25 mas%; Nb 0.1 mas%~0.4 mas%, Ti 0.18 mas%~0.4 mas%; Cr 0.21~0.4 mas%, and not 0; the surface of the NdFeB main phase grains is distributed with the Cr; Or, the sintered magnet is composed of the following components in mass percentage: Nd 29.5~32 mas%; Tb 0.1 mas%~0.5 mas%; B 0.95 mas%~1 mas%; Cu 0.16~0.4 mas%; Ga 0.05 mas%~0.25 mas%; Nb 0.1 mas%~0.4 mas%, Ti 0.18 mas%~0.4 mas%; W 0.23~0.4 mas%, and not 0; the surface of the NdFeB main phase grains is distributed with the W.

15. The sintered magnet according to claim 12, wherein The content of R is 29.6 mas% or 31 mas%, and mas% is the mass percentage of each component in the sintered magnet.

16. The sintered magnet according to claim 12, wherein The R includes PrNd, and the content of PrNd is 0~33 mas%, and not 0, and mas% is the mass percentage of each component in the sintered magnet material.

17. The sintered magnet according to claim 12, wherein The R includes Nd, the content of the Nd is 0-33 mas%, and is not 0, and mas% is the mass percentage of each component in the material for sintered magnet.

18. The sintered magnet according to claim 12, wherein The R includes heavy rare earth element RH, the content of the RH is 0-2.5 mas%, and is not 0, and mas% is the mass percentage of each component in the material for sintered magnet; And / or, the R includes heavy rare earth element RH, the RH includes one or more of Tb, Dy, Ho and Gd; And / or, the content of the B is 0.88 mas% or 0.95 mas%, and mas% is the mass percentage of each component in the material for sintered magnet; And / or, the content of the Cu is 0.16 mas% or 0.3 mas%, and mas% is the mass percentage of each component in the material for sintered magnet; And / or, the content of the Ga is 0.25 mas%, and mas% is the mass percentage of each component in the material for sintered magnet; And / or, the content of the Fe is 68.4 mas%, 66.4 mas% or 64.2 mas%, and mas% is the mass percentage of each component in the material for sintered magnet; And / or, the content of the C is 0.155 mas%, 0.1178 mas%, 0.106 mas%, 0.111 mas%, 0.1105 mas%, 0.128 mas%, 0.153 mas%, 0.105 mas%, 0.124 mas%, 0.149 mas%, 0.124 mas% or 0.1475 mas%, and mas% is the mass percentage of each component in the sintered magnet; And / or, the sintered magnet further includes Al, the content of the Al is 0-0.5 mas%, and is not 0, and mas% is the mass percentage of each component in the sintered magnet; And / or, the sintered magnet further includes Co, the content of the Co is 0-2 mas%, and is not 0, and mas% is the mass percentage of each component in the sintered magnet; And / or, the sintered magnet includes Nb, the content of the Nb is 0-0.4 mas%, and is not 0, and mas% is the mass percentage of each component in the sintered magnet; And / or, the sintered magnet includes Ti, the content of the Ti is 0-0.4 mas%, and is not 0, and mas% is the mass percentage of each component in the sintered magnet; And / or, the sintered magnet includes Cr, the content of the Cr is 0-0.4 mas%, and is not 0, and mas% is the mass percentage of each component in the sintered magnet; And / or, the sintered magnet includes W, the content of the W is 0-0.4 mas%, and is not 0, and mas% is the mass percentage of each component in the sintered magnet; And / or, when the sintered magnet includes Zr, the content of the Zr is 0-0.5 mas%, and is not 0, and mas% is the mass percentage of each component in the sintered magnet; and / or, when the sintered magnet includes Ta, the content of the Ta is 0 to 0.5 mas% and is not 0, and mas% is the mass percentage of each component with respect to the sintered magnet.

19. The sintered magnet according to claim 12, wherein The R includes PrNd, and the content of the PrNd is 29.5 mas% or 31 mas%, and mas% is the mass percentage of each component with respect to the sintered magnet material.

20. The sintered magnet according to claim 12, wherein The R includes Nd, and the content of the Nd is 29.5 mas%, and mas% is the mass percentage of each component with respect to the sintered magnet material.

21. The sintered magnet according to claim 12, wherein The R includes heavy rare earth elements RH, the RH includes Tb, and the content of the Tb is 0 to 0.5 mas% and is not 0, and mas% is the mass percentage of each component with respect to the sintered magnet; and / or, the R includes heavy rare earth elements RH, the RH includes Dy, and the content of the Dy is 0 to 2.5 mas% and is not 0, and mas% is the mass percentage of each component with respect to the sintered magnet; and / or, the sintered magnet further includes Al, and the content of the Al is 0.3 mas%, and mas% is the mass percentage of each component with respect to the sintered magnet; and / or, the sintered magnet further includes Co, and the content of the Co is 0 to 1.6 mas% and is not 0, and mas% is the mass percentage of each component with respect to the sintered magnet; and / or, when the sintered magnet includes Nb, the content of the Nb is 0.1 mas% or 0.32 mas%, and mas% is the mass percentage of each component with respect to the sintered magnet; and / or, when the sintered magnet includes Ti, the content of the Ti is 0.18 mas%, 0.15 mas%, 0.25 mas%, 0.3 mas% or 0.35 mas%, and mas% is the mass percentage of each component with respect to the sintered magnet; and / or, when the sintered magnet includes Cr, the content of the Cr is 0.21 mas%, and mas% is the mass percentage of each component with respect to the sintered magnet; and / or, when the sintered magnet includes W, the content of the W is 0.23 mas%, and mas% is the mass percentage of each component with respect to the sintered magnet; and / or, when the sintered magnet includes Zr, the content of the Zr is 0.1 mas% or 0.3 mas%, and mas% is the mass percentage of each component with respect to the sintered magnet; and / or, when the sintered magnet includes Ta, the content of the Ta is 0.23 mas%, and mas% is the mass percentage of each component with respect to the sintered magnet.

22. The sintered magnet according to claim 12, wherein The R includes heavy rare earth elements RH, the RH includes Tb, and the content of the Tb is 0.1 mas%, and mas% is the mass percentage of each component with respect to the sintered magnet; and / or, the sintered magnet further includes Co, and the content of the Co is 0.5 mas%, and mas% is the mass percentage of each component with respect to the sintered magnet.

23. A rare earth permanent magnet, characterized by, It includes the following components in mass percentage: R: 29 mas% to 33 mas%, the R is a rare earth element; B: 0.86 mas% to 1 mas%; M: 0~0.5mas%, and not 0; the M includes one or more of Ti, Nb, Zr, Cr and Ta; Cu: 0~0.5mas%, and not 0; Ga: 0~0.5mas%, and not 0; Fe: 64mas%~70mas%; C: 0.1~0.2mas%; mas% is the mass percentage of each component in the rare earth permanent magnet; the rare earth permanent magnet includes NdFeB main phase grains, two-particle grain boundaries adjacent to the NdFeB main phase grains, and three-prong grain boundaries, the three-prong grain boundaries are distributed with hcp structure rare earth carbides; the two-particle grain boundaries are distributed with RE-Cu-Fe-C-Ga phase; The surface of the NdFeB main phase grains is distributed with all or part of the M elements.

24. The rare earth permanent magnet of claim 23, wherein, The rare earth carbide is one or more of NdC, PrC, TbC and DyC; and / or the triple junctions are further distributed with Nd6(FeGa) 14； And / or, the content of R is 29.5mas%~32mas%, mas% is the mass percentage of each component in the rare earth permanent magnet; And / or, the R includes PrNd and / or Nd; And / or, the R includes heavy rare earth elements RH; And / or, the content of B is 0.86mas%~0.99mas%, mas% is the mass percentage of each component in the rare earth permanent magnet; And / or, the content of Cu is 0~0.4mas%, and not 0, mas% is the mass percentage of each component in the rare earth permanent magnet; And / or, the content of Ga is 0.05mas%~0.5mas%, mas% is the mass percentage of each component in the rare earth permanent magnet; And / or, the content of Fe is 64mas%~69mas%, mas% is the mass percentage of each component in the rare earth permanent magnet; And / or, the content of C is 0.1mas%~0.16mas%, mas% is the mass percentage of each component in the rare earth permanent magnet; And / or, the rare earth permanent magnet further includes Al; And / or, the rare earth permanent magnet further includes Co.

25. The rare earth permanent magnet of claim 23, wherein, In mass percentage, the rare earth permanent magnet is composed of: PrNd 29.5~32mas%; Dy 0~2.5mas%, and not 0; B 0.95mas%~1mas%; Cu 0.16~0.4mas%; Ga 0.05mas%~0.25mas%; Co 0.5mas%~1.6mas%; Al 0.3mas%~0.5mas%; Ti 0~0.4mas%, and not 0, C 0.1mas%~0.16mas%; the surface of the NdFeB main phase grains is distributed with the Ti; Or, in mass percentage, the rare earth permanent magnet is composed of the following components: PrNd 29.5~32 mas%; Dy 0~2.5 mas%, and not 0; B 0.95 mas%~1 mas%; Cu 0.16~0.4 mas%; Ga 0.05 mas%~0.25 mas%; Co 0.5 mas%~1.6 mas%; Al 0.3 mas%~0.5 mas%; Zr 0~0.4 mas%, and not 0, C 0.1 mas%~0.16 mas%; the surface of the NdFeB main phase grain is distributed with the Zr; Or, in mass percentage, the rare earth permanent magnet is composed of the following components: PrNd 29.5~33 mas%; B 0.86 mas%~0.88 mas%; Cu 0.16~0.4 mas%; Ga 0.25 mas%~0.5 mas%; Co 0.5 mas%~1.6 mas%; Ti 0~0.4 mas%, and not 0; the surface of the NdFeB main phase grain is distributed with the Ti; Or, in mass percentage, the rare earth permanent magnet is composed of the following components: PrNd 29.5~33 mas%; B 0.86 mas%~0.88 mas%; Cu 0.16~0.4 mas%; Ga 0.25 mas%~0.5 mas%; Co 0.5 mas%~1.6 mas%; Zr 0~0.5 mas%, and not 0; the surface of the NdFeB main phase grain is distributed with the Zr; Or, in mass percentage, the rare earth permanent magnet is composed of the following components: Nd 29.5~32 mas%; Tb 0.1 mas%~0.5 mas%; B 0.95 mas%~1 mas%; Cu 0.16~0.4 mas%; Ga 0.05 mas%~0.25 mas%; Nb 0.32 mas%~0.4 mas%, Ti 0.18 mas%~0.4 mas%, the surface of the NdFeB main phase grain is distributed with 0.22 mas% Nb element; Or, in mass percentage, the rare earth permanent magnet is composed of the following components: Nd 29.5~32 mas%; Tb 0.1 mas%~0.5 mas%; B 0.95 mas%~1 mas%; Cu 0.16~0.4 mas%; Ga 0.05 mas%~0.25 mas%; Nb 0.1 mas%~0.4 mas%, Ti 0.18 mas%~0.4 mas%; Ta 0.23~0.5 mas%, and not 0; the surface of the NdFeB main phase grain is distributed with the Ta; or, in mass percentage, the rare earth permanent magnet consists of the following components: Nd 29.5~32 mas%; Tb 0.1 mas%~0.5 mas%; B 0.95 mas%~1 mas%; Cu 0.16~0.4 mas%; Ga 0.05 mas%~0.25 mas%; Nb 0.1 mas%~0.4 mas%, Ti 0.18 mas%~0.4 mas%; Cr 0.21~0.4 mas%, and not 0; the surface of the NdFeB main phase grains is distributed with the Cr; or, in mass percentage, the rare earth permanent magnet consists of the following components: Nd 29.5~32 mas%; Tb 0.1 mas%~0.5 mas%; B 0.95 mas%~1 mas%; Cu 0.16~0.4 mas%; Ga 0.05 mas%~0.25 mas%; Nb 0.1 mas%~0.4 mas%, Ti 0.18 mas%~0.4 mas%; W 0.23~0.4 mas%, and not 0; the surface of the NdFeB main phase grains is distributed with the W.

26. The rare earth permanent magnet of claim 23, wherein, The content of R is 29.6 mas% or 31 mas%, and mas% is the mass percentage of each component in the rare earth permanent magnet.

27. The rare earth permanent magnet of claim 23, wherein, The R includes PrNd, and the content of PrNd is 0~33 mas%, and not 0, and mas% is the mass percentage of each component in the rare earth permanent magnet.

28. The rare earth permanent magnet of claim 23, wherein, The R includes Nd, and the content of Nd is 0~33 mas%, and not 0, and mas% is the mass percentage of each component in the rare earth permanent magnet.

29. The rare earth permanent magnet of claim 23, wherein, The R includes heavy rare earth elements RH, and the content of RH is 0-2.5 mas%, and not 0, and mas% is the mass percentage of each component in the rare earth permanent magnet; And / or, the R includes heavy rare earth elements RH, and the RH includes one or more of Tb, Dy, Ho and Gd; And / or, the content of B is 0.88 mas% or 0.95 mas%, and mas% is the mass percentage of each component in the rare earth permanent magnet; And / or, the content of Cu is 0.16 mas% or 0.3 mas%, and mas% is the mass percentage of each component in the rare earth permanent magnet; And / or, the content of Ga is 0.25 mas%, and mas% is the mass percentage of each component in the rare earth permanent magnet; And / or, the content of Fe is 68.4 mas%, 66.4 mas% or 64.2 mas%, and mas% is the mass percentage of each component in the rare earth permanent magnet; And / or, the content of C is 0.155 mas%, 0.1178 mas%, 0.106 mas%, 0.111 mas%, 0.1105 mas%, 0.128 mas%, 0.153 mas%, 0.105 mas%, 0.124 mas%, 0.149 mas%, 0.124 mas% or 0.1475 mas%, and mas% is the mass percentage of each component in the rare earth permanent magnet; And / or, the rare earth permanent magnet further comprises Al, and the content of Al is 0-0.5 mas% and is not 0, and mas% is the mass percentage of each component in the rare earth permanent magnet; And / or, the rare earth permanent magnet further comprises Co, and the content of Co is 0-2 mas% and is not 0, and mas% is the mass percentage of each component in the rare earth permanent magnet; And / or, the rare earth permanent magnet comprises Nb, and the content of Nb is 0-0.4 mas% and is not 0, and mas% is the mass percentage of each component in the rare earth permanent magnet; And / or, the rare earth permanent magnet comprises Ti, and the content of Ti is 0-0.4 mas% and is not 0, and mas% is the mass percentage of each component in the rare earth permanent magnet; And / or, the rare earth permanent magnet comprises Cr, and the content of Cr is 0-0.4 mas% and is not 0, and mas% is the mass percentage of each component in the rare earth permanent magnet; And / or, the rare earth permanent magnet comprises W, and the content of W is 0-0.4 mas% and is not 0, and mas% is the mass percentage of each component in the rare earth permanent magnet; And / or, the rare earth permanent magnet comprises Zr, and the content of Zr is 0-0.5 mas% and is not 0, and mas% is the mass percentage of each component in the rare earth permanent magnet; And / or, the rare earth permanent magnet comprises Ta, and the content of Ta is 0-0.5 mas% and is not 0, and mas% is the mass percentage of each component in the rare earth permanent magnet.

30. The rare earth permanent magnet of claim 23, wherein, The R comprises PrNd, and the content of PrNd is 29.5 mas% or 31 mas%, and mas% is the mass percentage of each component in the rare earth permanent magnet.

31. The rare earth permanent magnet of claim 23, wherein, The R comprises Nd, and the content of Nd is 29.5 mas%, and mas% is the mass percentage of each component in the rare earth permanent magnet.

32. The rare earth permanent magnet of claim 23, wherein, The R comprises heavy rare earth elements RH, and the RH comprises Tb, and the content of Tb is 0-0.5 mas% and is not 0, and mas% is the mass percentage of each component in the rare earth permanent magnet; And / or, the R comprises heavy rare earth elements RH, and the RH comprises Dy, and the content of Dy is 0-2.5 mas% and is not 0, and mas% is the mass percentage of each component in the rare earth permanent magnet; And / or, the rare earth permanent magnet further comprises Al, and the content of Al is 0.3 mas%, and mas% is the mass percentage of each component in the rare earth permanent magnet; And / or, the rare earth permanent magnet further comprises Co, the content of the Co is 0~1.6mas%, and the mas% is the mass percentage of each component in the rare earth permanent magnet; And / or, the rare earth permanent magnet comprises Nb, the content of the Nb is 0.1mas% or 0.32mas%, and the mas% is the mass percentage of each component in the rare earth permanent magnet; And / or, the rare earth permanent magnet comprises Ti, the content of the Ti is 0.18mas%, 0.15mas%, 0.25mas%, 0.3mas% or 0.35mas%, and the mas% is the mass percentage of each component in the rare earth permanent magnet; And / or, the rare earth permanent magnet comprises Cr, the content of the Cr is 0.21mas%, and the mas% is the mass percentage of each component in the rare earth permanent magnet; And / or, the rare earth permanent magnet comprises W, the content of the W is 0.23mas%, and the mas% is the mass percentage of each component in the rare earth permanent magnet; And / or, the rare earth permanent magnet comprises Zr, the content of the Zr is 0.1mas% or 0.3mas%, and the mas% is the mass percentage of each component in the rare earth permanent magnet; And / or, the rare earth permanent magnet comprises Ta, the content of the Ta is 0.23mas%, and the mas% is the mass percentage of each component in the rare earth permanent magnet.

33. The rare earth permanent magnet of claim 23, wherein, The R comprises heavy rare earth elements RH, the RH comprises Tb, and the content of the Tb is 0.1mas%, and the mas% is the mass percentage of each component in the rare earth permanent magnet; And / or, the rare earth permanent magnet further comprises Co, the content of the Co is 0.5mas%, and the mas% is the mass percentage of each component in the rare earth permanent magnet.

34. A method of producing a sintered magnet, characterized by: The preparation method comprises the following steps: melting the first component in the raw material of the sintered magnet as claimed in any one of claims 1-11, and coarsely crushing to obtain a coarse powder; The coarse powder is finely crushed with a mixture of the antioxidant in a dosage of 40%-60% to obtain a fine powder; The fine powder is then formed and sintered with a mixture of the remaining second component.

35. The production process of a sintered magnet according to claim 34, wherein The melting temperature is 1300-1700℃; And / or, the melting equipment is a high-frequency vacuum melting furnace and / or a medium-frequency vacuum melting furnace; And / or, the coarse crushing is hydrogen crushing; And / or, the fine crushing is airflow milling; And / or, the sintering temperature is 1000-1200℃; And / or, the sintering time is 0.5-10h.

36. The production method of a sintered magnet according to claim 35, wherein The melting temperature is 1500℃; And / or, the hydrogen crushing comprises hydrogen absorption, hydrogen desorption and cooling treatment; And / or, the airflow milling pressure is 0.1-2MPa; And / or, the sintering temperature is 1030-1090℃; And / or, the sintering time is 2-8h.

37. The production method of a sintered magnet according to Claim 36, wherein The hydrogen absorption temperature is 20-200℃; And / or, the hydrogen absorption pressure is 50-600kPa; And / or, the hydrogen desorption temperature is 400-650℃; And / or, the airflow milling pressure is 0.5-0.7MPa.

38. The production method of a sintered magnet according to claim 36, wherein The hydrogen absorption temperature is 20-40℃; And / or, the hydrogen absorption pressure is 90kPa; And / or, the hydrogen desorption temperature is 550℃; And / or, the jet mill powdering pressure is 0.65MPa.

39. A method of producing a rare earth permanent magnet, characterized by, The preparation method comprises the following steps: preparing the sintered magnet according to any one of claims 12-22 by one of the following two methods: Method one: sequentially performing primary aging treatment and secondary aging treatment; Method two: sequentially performing grain boundary diffusion treatment and secondary aging treatment.

40. The method of producing a rare earth magnet as claimed in claim 39, wherein In method one, the primary aging treatment temperature is 880-920℃; And / or, in method one, the primary aging time is 2-4h.

41. The method of making a rare earth permanent magnet as claimed in claim 39, wherein, In method one, the primary aging treatment temperature is 900℃; And / or, in method one, the primary aging time is 2h.

42. The method of making a rare earth permanent magnet as claimed in claim 39, wherein, In method two, the heavy rare earth element in the grain boundary diffusion treatment comprises Tb and / or Dy; And / or, in method two, the grain boundary diffusion treatment is: evaporating, coating or sputtering attaching a substance containing Tb or a substance containing Dy on the surface of the sintered magnet, and then performing diffusion heat treatment.

43. The method of making a rare earth permanent magnet as claimed in claim 42, wherein, The substance containing Tb or Dy is Tb or Dy metal, a compound or an alloy containing Tb or Dy; And / or, the grain boundary diffusion treatment temperature is 800-900℃; And / or, the grain boundary diffusion treatment time is 12-48h.

44. The method of making a rare earth permanent magnet as claimed in claim 42, wherein, The grain boundary diffusion treatment temperature is 850℃; And / or, the grain boundary diffusion treatment time is 24h.

45. The method of making a rare earth permanent magnet as claimed in claim 39, wherein, In method one and / or method two, the secondary aging treatment temperature is 460-520℃; And / or, in method one and / or method two, the secondary aging time is 2-4h.

46. The method of making a rare earth permanent magnet as claimed in claim 39, wherein, In method one and / or method two, the secondary aging treatment temperature is 490℃; In method one and / or method two, the secondary aging time is 2h.

47. Use of the sintered magnet according to any one of claims 12-22 and / or the rare earth permanent magnet according to any one of claims 23-33 as a rotor of a permanent magnet motor.

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