WO2023093495A1 - Rare earth permanent magnet, sintered magnet material, preparation method, and use - Google Patents

Abstract

Disclosed in the present invention are a rare earth permanent magnet, a sintered magnet material, a preparation method, and the use. A material for a sintered magnet comprises a first component and a second component. The first component comprises: R: 29-33 mass%, R being a rare earth element; B: 0.86-1 mass%; Cu: 0-0.5 mass%, excluding 0; Ga: 0-0.5 mass%, excluding 0; and Fe: 64-70 mass%. The second component comprises an antioxidant and a high-melting-point carbide, wherein 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; and the content of the high-melting-point carbide is 0.1-0.5 mass%, and mass% is the mass percentage of each component in the material for a sintered magnet. Both the residual magnetism and the coercive force of the sintered magnet of the present invention can be kept at a high level.

Description

Rare earth permanent magnet, sintered magnet material, preparation method, application technical field

The invention relates to a rare earth permanent magnet, a sintered magnet material, a preparation method and an application.

Background technique

Sintered NdFeB magnets are the most magnetic permanent magnets in the contemporary era. They have excellent characteristics such as high magnetic energy product and high cost performance. With the continuous expansion of the application range of permanent magnets, people's demand for them has also increased, and higher requirements have been put forward for the magnetic properties of permanent magnets.

In the process of preparing NdFeB magnet materials in the prior art, a certain amount of lubricant or antioxidant will be mixed in the jet milling process or molding process, that is, a certain amount of carbon element will be introduced, and a high carbon content will lead to coercive power drop.

Therefore, there is an urgent need for an NdFeB magnet material with high magnetic properties even if an antioxidant is added during the preparation process.

Contents of the invention

The technical problem to be solved by the present invention is to provide a rare earth permanent magnet, sintered magnet material, preparation method, application.

The inventor found through creative work that adding high-melting-point carbides before magnet orientation molding can make rare-earth permanent magnets with traditional antioxidants still have excellent magnetic properties at high carbon content; the reason is that high-melting point carbonization during sintering On the one hand, the decomposed carbon forms rare earth carbides with a (face centered cubic) fcc structure at the trifurcation grain boundary, and forms rare earth carbides with a (hexagonal close-packed) hcp structure and RE in the subsequent secondary aging process. -Cu-Fe-C-Ga grain boundary phase, these two grain boundary structures have better wettability to the main phase, strengthen the continuity of the grain boundary, and play a better role in magnetic isolation; on the other hand, due to the high melting point The high melting point elements obtained by the decomposition of carbides are distributed on the surface of the NdFeB main phase grains and play the role of magnetic domain pinning. The synergistic effect of the above two aspects makes the rare earth permanent magnets still maintain good magnetic properties.

The present invention solves the problems of the technologies described above through the following solutions:

The present invention provides a material for sintered magnets, which includes a first component and a second component, in terms of mass percentage, the first component includes:

R: 29mas%-33mas%, the R is 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 includes an antioxidant and a refractory carbide including titanium carbide, zirconium carbide, chromium carbide, niobium carbide, tantalum carbide, molybdenum carbide, tungsten carbide, vanadium carbide and hafnium carbide. One or more; the content of the high melting point carbide is 0.1-0.5mas%, and mas% is the mass percentage of each component in the material for sintered magnet.

In the present invention, preferably, the content of R is 29.5mas%-32mas%, such as 29.6mas% or 31mas%, where mas% is the mass percentage of each component in the material for sintered magnet.

In the present invention, preferably, the R includes PrNd and/or Nd.

When the R includes PrNd, the content of the PrNd is preferably 0-33mas%, and is not 0, such as 29.5mas% or 31mas%, mas% is the mass of each component in the material for sintered magnets percentage.

When the R includes Nd, the content of Nd is preferably 0-33mas%, but not 0, for example, 29.5mas%, where mas% is the mass percentage of each component in the material for the sintered magnet.

In the present invention, preferably, the R includes heavy rare earth element RH. Preferably, the content of RH is 0-2.5mas%, but not 0, and mas% is the mass percentage of each component in the material for sintered magnet. Preferably, the RH includes one or more of Tb, Dy, Ho and Gd. When the RH includes Tb, the content of Tb is preferably 0-0.5mas%, but not 0, such as 0.1mas%, where mas% is the mass percentage of each component in the material for the sintered magnet. When the RH includes Dy, the content of Dy is preferably 0-2.5mas%, and not 0, where mas% is the mass percentage of each component in the material for the sintered magnet.

In the present invention, the content of B is preferably 0.86mas%-0.99mas%, such as 0.88mas% or 0.95mas%, where mas% is the mass percentage of each component in the material for sintered magnet.

In the present invention, the content of Cu is preferably 0-0.4mas%, and not 0, such as 0.16mas% or 0.3mas%, where mas% is the mass percentage of each component in the material for sintered magnet.

In the present invention, the Ga content is preferably 0.05mas%-0.5mas%, such as 0.25mas%, where mas% is the mass percentage of each component in the material for the sintered magnet.

In the present invention, the content of Fe is preferably 64.5mas%-69mas%, such as 68.78mas%, 66.72mas% or 64.74mas%, where mas% is the mass percentage of each component in the material for sintered magnet.

In the present invention, the antioxidant can be an antioxidant or lubricant conventionally used in the art, such as magnesium stearate and/or tributyl borate. The content of the antioxidant is generally 0.05mas%-0.15mas%.

In the present invention, 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 refractory carbide is preferably 0.2-0.5mas%, and mas% is the mass percentage of each component in the material for the sintered magnet.

In the present invention, the preparation process of the sintered magnet generally includes the steps of coarse crushing and fine crushing, and the refractory carbide in the second component is preferably used after the fine crushing and before the molding Add to. Preferably, the antioxidant in the second component is added after the coarse pulverization but before the fine pulverization and after the fine pulverization but before the shaping.

In the present invention, preferably, the first component further includes Co. The content of Co is preferably 0-2mas%, and not 0, more preferably 0-1.6mas%, and not 0, such as 0.5mas%, and mas% is the proportion of each component in the sintered magnet The mass percentage of the material used.

In the present invention, preferably, the first component further includes Nb. The content of Nb is preferably 0-0.4mas%, and not 0, for example, 0.1mas%, where mas% is the mass percentage of each component in the material for the sintered magnet.

In the present invention, preferably, the first component further includes Ti. The Ti content is preferably 0-0.4mas%, and not 0, for example, 0.18mas%, where mas% is the mass percentage of each component in the material for the sintered magnet.

In the present invention, preferably, the first component further includes Al. The content of Al is preferably 0-0.5mas%, and not 0, for example, 0.3mas%, where mas% is the mass percentage of each component in the material for the sintered magnet.

In the present invention, the first component may further include one or more of Zr, Cr, Ta, Mo, W, V and Hf.

In the present invention, preferably, in terms of mass percentage, the material for sintered magnets is composed of the following components: the first component is: PrNd29.5-33mas%; Dy0-2.5mas%, and not 0 ; B0.95mas% ~ 1mas%; Cu0.16 ~ 0.4mas%; Ga0.05mas% ~ 0.25mas%; For ZrC or TiC 0.3mas%-0.5mas%, magnesium stearate 0.05mas%-0.15mas%.

In the present invention, preferably, in terms of mass percentage, the material for the sintered magnet is composed of the following components: the first component is: PrNd29.5-33mas%; B0.86mas%-0.88mas%; Cu0 .16～0.4mas%; Ga0.25mas%～0.5mas%; Co0.5mas%～1.6mas%; the second component is ZrC or TiC0.1mas%～0.5mas%, magnesium stearate 0.05mas % ~ 0.15mas%.

In the present invention, preferably, in terms of mass percentage, the material for the sintered magnet is composed of the following components: the first component is Nd29.5-33mas%; Tb0.1mas%-0.5mas%; B0 .95mas%～1mas%; Cu0.16～0.4mas%; Ga0.05mas%～0.25mas%; Nb0.1mas%～0.4mas%, Ti0.18mas%～0.4mas%, the second component is, WC, Cr3C2, TaC or NbC, 0.1mas%-0.5mas%, magnesium stearate 0.05mas%-0.15mas%.

In a preferred embodiment of the present invention, the type and amount of the material for the sintered magnet can be any one of the following numbers 1-12 (mas%):

The present invention also provides a sintered magnet, which comprises the following components in terms of mass percentage:

R: 29mas%-33mas%, the R is a rare earth element;

B: 0.86mas%～1mas%;

M: 0-0.5mas%, and not 0; said M includes one or more of Ti, Zr, Cr, Nb, Ta, Mo, W, V and Hf;

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 sintered magnet; the sintered magnet includes NdFeB main phase grains, two grain boundaries and triple grain boundaries adjacent to the NdFeB main phase grains, and the triple grain boundaries are distributed Rare earth carbides with fcc structure; all or part of the M elements are distributed on the surface of the NdFeB main phase grains.

In the present invention, "all or part of the M elements are distributed on the surface of the NdFeB main phase grains" means: when all the M elements are derived from refractory carbides, the NdFeB main phase grains All of the M elements are distributed on the surface of the NdFeB main phase grains; when only a part of the M elements are derived from refractory carbides, part of the M elements are distributed on the surface of the NdFeB main phase grains.

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

In the present invention, preferably, the content of R is 29.5mas%-32mas%, such as 29.6mas% or 31mas%, where mas% is the mass percentage of each component in the sintered magnet.

In the present invention, preferably, the R includes PrNd and/or Nd.

When the R includes PrNd, the content of the PrNd is preferably 0-33mas%, but not 0, such as 29.5mas% or 31mas%, where mas% is the mass percentage of each component in the sintered magnet.

When the R includes Nd, the content of Nd is preferably 0-33mas%, but not 0, such as 29.5mas%, where mas% is the mass percentage of each component in the sintered magnet.

In the present invention, preferably, the R includes heavy rare earth element RH. Preferably, the content of RH is 0-2.5mas%, but not 0, and mas% is the mass percentage of each component in the sintered magnet. Preferably, the RH includes one or more of Tb, Dy, Ho and Gd. When the RH includes Tb, the content of Tb is preferably 0-0.5mas%, but not 0, such as 0.1mas%, where mas% is the mass percentage of each component in the sintered magnet. When the RH includes Dy, the content of Dy is preferably 0-2.5mas%, and not 0, where mas% is the mass percentage of each component in the sintered magnet.

In the present invention, the content of B is preferably 0.86mas%-0.99mas%, such as 0.88mas% or 0.95mas%, where mas% is the mass percentage of each component in the sintered magnet.

In the present invention, the content of Cu is preferably 0-0.4mas%, but not 0, such as 0.16mas% or 0.3mas%, where mas% is the mass percentage of each component in the sintered magnet.

In the present invention, the Ga content is preferably 0.05mas%-0.5mas%, such as 0.25mas%, where mas% is the mass percentage of each component in the sintered magnet.

In the present invention, the content of Fe is preferably 64mas%-69mas%, such as 68.4mas%, 66.4mas% or 64.2mas%, where mas% is the mass percentage of each component in the sintered magnet.

In the present invention, the content of C is preferably 0.1mas% to 0.16mas%, such as 0.155mas%, 0.1178mas%, 0.106mas%, 0.111mas%, 0.1105mas%, 0.128mas%, 0.153mas%, 0.105mas%, 0.124mas%, 0.149mas%, 0.124mas% or 0.1475mas%, where mas% is the mass percentage of each component in the sintered magnet.

In the present invention, preferably, the sintered magnet further includes Al. The content of Al is preferably 0-0.5mas%, but not 0, for example, 0.3mas%, where mas% is the mass percentage of each component in the sintered magnet.

In the present invention, preferably, the sintered magnet further includes Co. The content of Co is preferably 0-2mas%, and not 0, more preferably 0-1.6mas%, and not 0, such as 0.5mas%, and mas% is the proportion of each component in the sintered magnet mass percentage.

In the present invention, the M preferably includes one or more of Ti, Nb, Zr, Cr and Ta.

When the sintered magnet includes Nb, the content of Nb is preferably 0-0.4mas%, and not 0, such as 0.1mas% or 0.32mas%, where mas% is the percentage of each component in the sintered magnet mass percentage.

When the sintered magnet includes Ti, the content of Ti is preferably 0-0.4mas%, and not 0, such as 0.18mas%, 0.15mas%, 0.25mas%, 0.3mas% or 0.35mas%, mas% is the mass percentage of each component in the sintered magnet.

When the sintered magnet includes Cr, the content of Cr is preferably 0-0.4mas%, but not 0, such as 0.21mas%, where mas% is the mass percentage of each component in the sintered magnet.

When the sintered magnet includes W, the content of W is preferably 0-0.4mas%, but not 0, such as 0.23mas%, where mas% is the mass percentage of each component in the sintered magnet.

When the sintered magnet includes Zr, the content of Zr is preferably 0-0.5mas%, and is not 0, such as 0.1mas% or 0.3mas%, and mas% is the percentage of each component in the sintered magnet. mass percentage.

When the sintered magnet includes Ta, the content of Ta is preferably 0-0.5mas%, but not 0, such as 0.23mas%, where mas% is the mass percentage of each component in the sintered magnet.

In the present invention, preferably, in terms of mass percentage, the sintered magnet is composed of the following components: PrNd29.5-33mas%; Dy0-2.5mas% and not 0; B0.95mas%-1mas%; Cu0 .16～0.4mas%; Ga0.05mas%～0.25mas%; Co0.5mas%～1.6mas%; Al0.3mas%～0.5mas%; Ti0～0.4mas% and not 0, C0.1mas%～ 0.16mas%; the sintered magnet includes NdFeB main phase grains, two-grain grain boundaries adjacent to the NdFeB main phase grains, and trifurcated grain boundaries, and the trifurcated grain boundaries are distributed with rare earth carbides of fcc structure; the NdFeB The Ti element is distributed on the surface of the main phase grains.

In the present invention, preferably, in terms of mass percentage, the sintered magnet is composed of the following components: PrNd29.5-33mas%; Dy0-2.5mas% and not 0; B0.95mas%-1mas%; Cu0 .16～0.4mas%; Ga0.05mas%～0.25mas%; Co0.5mas%～1.6mas%; Al0.3mas%～0.5mas%; Zr0～0.4mas% and not 0, C0.1mas%～ 0.16mas%; the sintered magnet includes NdFeB main phase grains, two-grain grain boundaries adjacent to the NdFeB main phase grains, and trifurcated grain boundaries, and the trifurcated grain boundaries are distributed with rare earth carbides of fcc structure; the NdFeB The Zr element is distributed on the surface of the main phase grains.

In the present invention, preferably, in terms of mass percentage, the sintered magnet is composed of the following components: PrNd29.5-33mas%; B0.86mas%-0.88mas%; Cu0.16-0.4mas%; Ga0.25mas% %～0.5mas%; Co0.5mas%～1.6mas%; Ti0～0.4mas%, and not 0; the sintered magnet includes NdFeB main phase grains and two grain boundaries adjacent to the NdFeB main phase grains and trifurcated grain boundaries, the trifurcated grain boundaries are distributed with rare earth carbides of fcc structure; the surface of the NdFeB main phase grains is distributed with the Ti element.

In the present invention, preferably, in terms of mass percentage, the sintered magnet is composed of the following components: PrNd29.5-33mas%; B0.86mas%-0.88mas%; Cu0.16-0.4mas%; Ga0.25mas% %～0.5mas%; Co0.5mas%～1.6mas%; Zr0～0.5mas%, and not 0; the sintered magnet includes NdFeB main phase grains and two grain boundaries adjacent to the NdFeB main phase grains and trifurcated grain boundaries, the trifurcated grain boundaries are distributed with rare earth carbides of fcc structure; the surface of the NdFeB main phase grains is distributed with the Zr element.

In the present invention, preferably, in terms of mass percentage, the sintered magnet consists of the following components: Nd29.5-33mas%; Tb0.1mas%-0.5mas%; B0.95mas%-1mas%; Cu0.16 ～0.4mas%; Ga0.05mas%～0.25mas%; Nb0.32mas%～0.4mas%, Ti0.18mas%～0.4mas%, the sintered magnet includes NdFeB main phase grains, adjacent to the NdFeB main phase grains The two-grain grain boundary and the three-fork grain boundary of the grain, the rare-earth carbides of the fcc structure are distributed in the three-fork grain boundary; the 0.22mas% Nb element is distributed on the surface of the NdFeB main phase grain.

In the present invention, preferably, in terms of mass percentage, the sintered magnet consists of the following components: Nd29.5-33mas%; Tb0.1mas%-0.5mas%; B0.95mas%-1mas%; Cu0.16 ～0.4mas%; Ga0.05mas%～0.25mas%; Nb0.1mas%～0.4mas%, Ti0.18mas%～0.4mas%; Ta0.23～0.5mas%, and not 0; the sintered magnet includes NdFeB main phase grains, two grain boundaries adjacent to the NdFeB main phase grains, and a trifurcated grain boundary, the trifurcated grain boundaries are distributed with rare earth carbides of fcc structure; the surface distribution of the NdFeB main phase grains varies Describe the Ta element.

In the present invention, preferably, in terms of mass percentage, the sintered magnet consists of the following components: Nd29.5-33mas%; Tb0.1mas%-0.5mas%; B0.95mas%-1mas%; Cu0.16 ～0.4mas%; Ga0.05mas%～0.25mas%; Nb0.1mas%～0.4mas%, Ti0.18mas%～0.4mas%; Cr0.21～0.4mas%, and not 0; the sintered magnet includes NdFeB main phase grains, two grain boundaries adjacent to the NdFeB main phase grains, and a trifurcated grain boundary, the trifurcated grain boundaries are distributed with rare earth carbides of fcc structure; the surface distribution of the NdFeB main phase grains varies Describe the Cr element.

In the present invention, preferably, in terms of mass percentage, the sintered magnet consists of the following components: Nd29.5-33mas%; Tb0.1mas%-0.5mas%; B0.95mas%-1mas%; Cu0.16 ～0.4mas%; Ga0.05mas%～0.25mas%; Nb0.1mas%～0.4mas%, Ti0.18mas%～0.4mas%; W0.23～0.4mas%, and not 0; the sintered magnet includes NdFeB main phase grains, two grain boundaries adjacent to the NdFeB main phase grains, and a trifurcated grain boundary, the trifurcated grain boundaries are distributed with rare earth carbides of fcc structure; the surface distribution of the NdFeB main phase grains varies Describe the W element.

In a preferred embodiment of the present invention, the type and amount of the sintered magnet can be any one of the following numbers 1-12 (mas%):

The present invention also provides a rare earth permanent magnet, which comprises the following components in terms of mass percentage:

R: 29mas%-33mas%, the R is a rare earth element;

B: 0.86mas%～1mas%;

M: 0-0.5mas%, and not 0; said M includes one or more of Ti, Zr, Cr, Nb, Ta, Mo, W, V and Hf;

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 percent of each component accounting for the rare earth permanent magnet;

The rare earth permanent magnet includes a two-grain grain boundary and a three-pronged grain boundary adjacent to the NdFeB main phase grain, and the three-pronged grain boundary is distributed with hcp structure rare earth carbides; the two-grain grain boundary is distributed Has RE-Cu-Fe-C-Ga phase;

All or part of the M elements are distributed on the surface of the NdFeB main phase grains.

In the present invention, "all or part of the M elements are distributed on the surface of the NdFeB main phase grains" means: when all the M elements are derived from refractory carbides, the NdFeB main phase grains All of the M elements are distributed on the surface of the NdFeB main phase grains; when only a part of the M elements are derived from refractory carbides, part of the M elements are distributed on the surface of the NdFeB main phase grains.

In the present invention, the trifurcated grain boundary generally refers to a place where three or more grain boundaries intersect.

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

In the present invention, preferably, Nd ₆ (FeGa) _{14 is distributed in the triple grain boundary.}

In the present invention, preferably, the content of R is 29.5mas%-32mas%, such as 29.6mas% or 31mas%, and mas% is the mass percentage of each component in the rare earth permanent magnet.

In the present invention, preferably, the R includes PrNd and/or Nd.

When the R includes PrNd, the content of the PrNd is preferably 0-33mas%, and is not 0, such as 29.5mas% or 31mas%, and mas% is the mass percentage of each component in the rare earth permanent magnet .

When the R includes Nd, the content of Nd is preferably 0-33mas%, but not 0, such as 29.5mas%, where mas% is the mass percentage of each component in the rare earth permanent magnet.

In the present invention, preferably, the R includes heavy rare earth element RH. Preferably, the content of RH is 0-2.5mas%, but not 0, and mas% is the mass percentage of each component in the rare earth permanent magnet. Preferably, the RH includes one or more of Tb, Dy, Ho and Gd. When the RH includes Tb, the content of Tb is preferably 0-0.5mas%, but not 0, such as 0.1mas%, where mas% is the mass percentage of each component in the rare earth permanent magnet. When the RH includes Dy, the content of Dy is preferably 0-2.5mas%, and not 0, and mas% is the mass percentage of each component in the rare earth permanent magnet.

In the present invention, the content of B is preferably 0.86mas%-0.99mas%, such as 0.88mas% or 0.95mas%, where mas% is the mass percentage of each component in the rare earth permanent magnet.

In the present invention, the content of Cu is preferably 0-0.4mas%, but not 0, such as 0.16mas% or 0.3mas%, where mas% is the mass percentage of each component in the rare earth permanent magnet.

In the present invention, the Ga content is preferably 0.05mas%˜0.5mas%, such as 0.25mas%, where mas% is the mass percentage of each component in the rare earth permanent magnet.

In the present invention, the content of Fe is preferably 64mas%-69mas%, such as 68.4mas%, 66.4mas% or 64.2mas%, where mas% is the mass percentage of each component in the rare earth permanent magnet.

In the present invention, the content of C is preferably 0.1mas% to 0.16mas%, such as 0.155mas%, 0.1178mas%, 0.106mas%, 0.111mas%, 0.1105mas%, 0.128mas%, 0.153mas%, 0.105mas%, 0.124mas%, 0.149mas%, 0.124mas% or 0.1475mas%, where mas% is the mass percentage of each component in the rare earth permanent magnet.

In the present invention, preferably, the rare earth permanent magnet further includes Al. The content of Al is preferably 0-0.5mas%, but not 0, for example, 0.3mas%, where mas% is the mass percentage of each component in the rare earth permanent magnet.

In the present invention, preferably, the rare earth permanent magnet further includes Co. The content of Co is preferably 0-2mas%, and not 0, more preferably 0-1.6mas%, and not 0, such as 0.5mas%, and mas% is the proportion of each component in the rare earth permanent The mass percent of the magnet.

In the present invention, the M preferably includes one or more of Ti, Nb, Zr, Cr and Ta.

When the rare earth permanent magnet includes Nb, the content of Nb is preferably 0-0.4mas%, and not 0, such as 0.1mas% or 0.32mas%, and mas% is the proportion of each component in the rare earth permanent magnet. The mass percent of the magnet.

When the rare earth permanent magnet includes Ti, the content of Ti is preferably 0-0.4mas%, and not 0, such as 0.18mas%, 0.15mas%, 0.25mas%, 0.3mas% or 0.35mas%. , mas% is the mass percentage of each component in the rare earth permanent magnet.

When the rare-earth permanent magnet includes Cr, the content of the Cr is preferably 0-0.4mas%, and not 0, such as 0.21mas%, and mas% is the mass percentage of each component in the rare-earth permanent magnet .

When the rare earth permanent magnet includes W, the content of W is preferably 0-0.4mas%, and not 0, such as 0.23mas%, where mas% is the mass percentage of each component in the rare earth permanent magnet .

When the rare earth permanent magnet includes Zr, the content of Zr is preferably 0 to 0.5mas%, and is not 0, such as 0.1mas% or 0.3mas%, and mas% is the proportion of each component in the rare earth permanent magnet. The mass percent of the magnet.

When the rare earth permanent magnet includes Ta, the content of Ta is preferably 0-0.5mas%, and not 0, such as 0.23mas%, where mas% is the mass percentage of each component in the rare earth permanent magnet .

In the present invention, preferably, in terms of mass percentage, the rare earth permanent magnet is composed of the following components: PrNd29.5-33mas%; Dy0-2.5mas%, but not 0; B0.95mas%-1mas%; Cu0.16～0.4mas%; Ga0.05mas%～0.25mas%; Co0.5mas%～1.6mas%; Al0.3mas%～0.5mas%; Ti0～0.4mas%, and not 0, C0.1mas% ～0.16mas%; the rare earth permanent magnet includes NdFeB main phase grains, two grain boundaries adjacent to the NdFeB main phase grains and a trifurcated grain boundary, and the trifurcated grain boundaries are distributed with rare earth carbides of hcp structure; the The RE-Cu-Fe-C-Ga phase is distributed on the grain boundary of the two particles; the Ti element is distributed on the surface of the NdFeB main phase grain.

In the present invention, preferably, in terms of mass percentage, the rare earth permanent magnet is composed of the following components: PrNd29.5-33mas%; Dy0-2.5mas%, but not 0; B0.95mas%-1mas%; Cu0.16～0.4mas%; Ga0.05mas%～0.25mas%; Co0.5mas%～1.6mas%; Al0.3mas%～0.5mas%; Zr0～0.4mas%, and not 0, C0.1mas% ～0.16mas%; the rare earth permanent magnet includes NdFeB main phase grains, two grain boundaries adjacent to the NdFeB main phase grains and a trifurcated grain boundary, and the trifurcated grain boundaries are distributed with rare earth carbides of hcp structure; the The RE-Cu-Fe-C-Ga phase is distributed on the grain boundary of the two particles; the Zr element is distributed on the surface of the NdFeB main phase grain.

In the present invention, preferably, in terms of mass percentage, the rare earth permanent magnet is composed of the following components: PrNd29.5-33mas%; B0.86mas%-0.88mas%; Cu0.16-0.4mas%; Ga0. 25mas% to 0.5mas%; Co0.5mas% to 1.6mas%; Ti0 to 0.4mas%, and not 0; the rare earth permanent magnet includes NdFeB main phase grains and two particles adjacent to the NdFeB main phase grains The grain boundary and the trifurcated grain boundary, the rare earth carbides of the hcp structure are distributed in the trifurcated grain boundary; the RE-Cu-Fe-C-Ga phase is distributed in the two-grain grain boundary; the surface of the NdFeB main phase grain is The Ti element is distributed.

In the present invention, preferably, in terms of mass percentage, the rare earth permanent magnet is composed of the following components: PrNd29.5-33mas%; B0.86mas%-0.88mas%; Cu0.16-0.4mas%; Ga0. 25mas%～0.5mas%; Co0.5mas%～1.6mas%; Zr0～0.5mas%, and not 0; the rare earth permanent magnet includes NdFeB main phase grains and two particles adjacent to the NdFeB main phase grains The grain boundary and the trifurcated grain boundary, the rare earth carbides of the hcp structure are distributed in the trifurcated grain boundary; the RE-Cu-Fe-C-Ga phase is distributed in the two-grain grain boundary; the surface of the NdFeB main phase grain is The Zr element is distributed.

In the present invention, preferably, in terms of mass percentage, the rare earth permanent magnet is composed of the following components: Nd29.5-33mas%; Tb0.1mas%-0.5mas%; B0.95mas%-1mas%; Cu0. 16～0.4mas%, Ga0.05mas%～0.25mas%, Nb0.32mas%～0.4mas%, Ti0.18mas%～0.4mas%, the rare earth permanent magnet includes NdFeB main phase grains, adjacent to the NdFeB main phase The two-grain grain boundary and the three-pronged grain boundary of the phase grain, the rare earth carbide of the hcp structure is distributed in the three-pronged grain boundary; the RE-Cu-Fe-C-Ga phase is distributed in the two-particle grain boundary; the NdFeB There are 0.22mas% Nb elements distributed on the surface of the main phase grains.

In the present invention, preferably, in terms of mass percentage, the rare earth permanent magnet is composed of the following components: Nd29.5-33mas%; Tb0.1mas%-0.5mas%; B0.95mas%-1mas%; Cu0. 16～0.4mas%; Ga0.05mas%～0.25mas%; Nb0.1mas%～0.4mas%, Ti0.18mas%～0.4mas%; Ta0.23～0.5mas%, and not 0; the rare earth The magnet includes NdFeB main phase grains, two-grain grain boundaries adjacent to the NdFeB main phase grains, and three-pronged grain boundaries. The three-pronged grain boundaries are distributed with rare earth carbides of hcp structure; the two-grain grain boundaries are distributed with RE- Cu-Fe-C-Ga phase; the Ta element is distributed on the surface of the NdFeB main phase grain.

In the present invention, preferably, in terms of mass percentage, the rare earth permanent magnet is composed of the following components: Nd29.5-33mas%; Tb0.1mas%-0.5mas%; B0.95mas%-1mas%; Cu0. 16～0.4mas%; Ga0.05mas%～0.25mas%; Nb0.1mas%～0.4mas%, Ti0.18mas%～0.4mas%; Cr0.21～0.4mas%, and not 0; The magnet includes NdFeB main phase grains, two-grain grain boundaries adjacent to the NdFeB main phase grains, and three-pronged grain boundaries. The three-pronged grain boundaries are distributed with rare earth carbides of hcp structure; the two-grain grain boundaries are distributed with RE- Cu-Fe-C-Ga phase; the Cr element is distributed on the surface of the NdFeB main phase grain.

In the present invention, preferably, in terms of mass percentage, the rare earth permanent magnet is composed of the following components: Nd29.5-33mas%; Tb0.1mas%-0.5mas%; B0.95mas%-1mas%; Cu0. 16～0.4mas%; Ga0.05mas%～0.25mas%; Nb0.1mas%～0.4mas%, Ti0.18mas%～0.4mas%; W0.23～0.4mas%, and not 0; the rare earth The magnet includes NdFeB main phase grains, two-grain grain boundaries adjacent to the NdFeB main phase grains, and three-pronged grain boundaries. The three-pronged grain boundaries are distributed with rare earth carbides of hcp structure; the two-grain grain boundaries are distributed with RE- Cu-Fe-C-Ga phase; the W element is distributed on the surface of the NdFeB main phase grain.

In a preferred embodiment of the present invention, the type and amount of the rare earth permanent magnet can be any one of the following numbers 1-12 (mas%):

The present invention also provides a method for preparing a sintered magnet. The preparation method includes the following steps: melting and coarsely pulverizing the first component in the above-mentioned material for the sintered magnet to obtain a coarse powder;

Finely pulverize the mixture of the coarse powder and 40%-60% of the antioxidant to obtain a fine powder;

Then, the mixture of the fine powder and the remaining second component is formed and sintered.

In the present invention, "40%-60% of the antioxidant used" means that the antioxidant added before finely pulverizing accounts for 40%-60% of the total amount of antioxidants.

In the present invention, the melting temperature may be 1300-1700°C, for example, 1500°C.

In the present invention, the melting equipment is generally a high-frequency vacuum melting furnace and/or a medium-frequency vacuum melting furnace. The intermediate frequency vacuum smelting furnace can be an intermediate frequency vacuum induction quick-setting belt throwing furnace.

In the present invention, the operation and conditions of the smelting can be the conventional smelting process in the field. Generally, the elements of the first component are smelted and casted by an ingot casting process or a quick-setting sheet process to obtain alloy flakes.

Those skilled in the art know that because rare earth elements are usually lost in the smelting and sintering process, in order to ensure the quality of the final product, an additional 0-0.3mas% of rare earth elements ( Generally Nd element), the percentage is the content of the additional rare earth element in the mass percentage of the material for the sintered magnet; in addition, the content of this additional rare earth element is not included in the scope of the raw material composition.

In the present invention, the coarse crushing may be hydrogen crushing. The hydrogen fragmentation generally includes hydrogen absorption, dehydrogenation and cooling treatment. The hydrogen absorption temperature is generally 20-200°C, preferably 20-40°C (ie room temperature). The hydrogen absorption pressure is generally 50-600kPa, for example 90kPa. The dehydrogenation temperature is generally 400-650°C, such as 550°C.

In the present invention, the fine pulverization may be jet milled powder. The gas flow in the jet milling may be, for example, nitrogen and/or argon. The pressure of the jet milling powder is generally 0.1-2 MPa, preferably 0.5-0.7 MPa, for example 0.65 MPa. The efficiency of jet milling powder can vary according to different equipment, for example, it can be 30-400kg/h, preferably 200kg/h.

In the present invention, the molding operation and conditions may be conventional molding processes in the art, such as magnetic field molding. The magnetic field strength of the magnetic field forming method is generally above 1.5T.

In the present invention, the sintering operation and conditions may be conventional sintering processes in the art, such as vacuum sintering process and/or inert atmosphere sintering process. The vacuum sintering process or the inert atmosphere sintering process are conventional operations in the field. When using an inert atmosphere sintering process, the initial sintering stage can be carried out under the condition that the degree of vacuum is lower than 0.5 Pa. The inert atmosphere may be an atmosphere containing an inert gas conventional in the art, not limited to helium and argon, and may also be nitrogen.

In the present invention, the sintering temperature may be 1000-1200°C, preferably 1030-1090°C.

In the present invention, the sintering time may be 0.5-10 hours, preferably 2-8 hours.

The invention also provides a sintered magnet prepared by the preparation method of the sintered magnet.

The present invention also provides a preparation method of a rare-earth permanent magnet, the preparation method comprising the following steps: the above-mentioned sintered magnet is prepared in one of the following two ways:

Method 1: After the first-level aging treatment and the second-level aging treatment in sequence;

Method 2: sequentially undergo grain boundary diffusion treatment and secondary aging treatment.

In the present invention, the heavy rare earth elements in the grain boundary diffusion treatment preferably include Tb and/or Dy.

In the present invention, the grain boundary diffusion treatment can be processed according to conventional processes in this field, for example, a substance containing Tb or a substance containing Dy is deposited on the surface of the sintered magnet by vapor deposition, coating or sputtering, and after diffusion Heat treatment, you can.

Wherein, the substance containing Tb or Dy may be Tb or Dy metal, a compound or alloy containing Tb or Dy.

Wherein, the temperature of the grain boundary diffusion treatment may be 800-900°C, for example, 850°C.

Wherein, the time for the grain boundary diffusion treatment may be 12-48 hours, such as 24 hours.

In the present invention, the temperature of the primary aging treatment is preferably 880°C-920°C, such as 900°C.

The time for the primary aging is preferably 2h-4h, for example 2h.

In the present invention, the temperature of the secondary aging treatment is preferably 460°C-520°C, for example 490°C.

The time for the secondary aging is preferably 2h-4h, for example 2h.

The present invention also provides a rare earth permanent magnet prepared by the above preparation method.

The invention also provides the application of the sintered magnet and/or the rare earth permanent magnet as the permanent magnet motor rotor.

On the basis of conforming to common knowledge in the field, the above-mentioned preferred conditions can be combined arbitrarily to obtain preferred examples of the present invention.

The reagents and raw materials used in the present invention are all commercially available.

The positive progress effect of the present invention is:

(1) The coercive force of rare earth permanent magnets under low B is above 15.8kOe, while maintaining high remanence;

(2) In a preferred embodiment of the present invention, the coercive force of the rare earth permanent magnets is above 25.6kOe, while maintaining a relatively high remanence.

Description of drawings

Fig. 1 is the EPMA distribution diagram of each element in embodiment 2.

Detailed ways

The present invention is further illustrated below by means of examples, but the present invention is not limited to the scope of the examples. For the experimental methods that do not specify specific conditions in the following examples, select according to conventional methods and conditions, or according to the product instructions.

Formulation and dosage (mas%) of materials for sintered magnets in table 1

Note: "/" in the above table means that this element is not included

Embodiment 1～4 and comparative example 1～3

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

(1) Melting process: According to the formula in Table 1, the prepared first component raw materials are vacuum smelted in a high-frequency vacuum melting furnace at 1500 ° C, and then in a medium-frequency vacuum induction quick-setting belt furnace Introduce argon gas, carry out casting, and then quench the alloy to obtain alloy flakes.

(2) Coarse crushing process: the alloy sheet is placed in a hydrogen crushing furnace, and the hydrogen crushing furnace where the quenched alloy is placed is evacuated at room temperature, and then hydrogen gas with a purity of 99.9% is introduced into the hydrogen crushing furnace to maintain the hydrogen gas. The pressure is 90kPa. After fully absorbing hydrogen, the temperature is raised while vacuuming, fully dehydrogenated, and then cooled to obtain a coarse powder. Wherein, the temperature of hydrogen absorption is room temperature, and the temperature of dehydrogenation is 550°C.

(3) Fine pulverization process: the mixture of the magnesium stearate (the total consumption of magnesium stearate is shown in Table 1) of the coarse powder and 50% consumption is placed in the jet abrasive tank, under nitrogen atmosphere, in the pulverization chamber pressure is 0.65 Under the condition of MPa, the mixture is subjected to jet milling (the efficiency of jet milling can vary according to equipment, for example, 200kg/h), to obtain a fine powder.

(4) Molding process: the fine powder is mixed with the remaining second component in Table 1, and pressed in a magnetic field strength above 1.5T to obtain a molded body.

(5) Sintering process: move each molded body to a sintering furnace for sintering, and sinter at 1030-1090°C for 8 hours under a vacuum lower than 0.5Pa to obtain a sintered magnet.

(6) Grain boundary diffusion and aging treatment process: After the surface of the sintered magnet is purified, Tb alloy containing 0.4mas% Tb is used to coat the surface of the sintered magnet, and diffused at a temperature of 850°C for 24h, then cooled to room temperature, and then Vacuum heat treatment at 490°C for 2 hours to obtain rare earth permanent magnets.

Embodiment 5～12 and comparative example 4～5

The only difference with the preparation method of Examples 1 to 4 and Comparative Example 1 is that step (6) is as follows:

(6) Aging treatment process: The sintered magnet is first vacuum heat treated at 900°C for 2 hours, and then vacuum heat treated at 490°C for 2 hours to obtain a rare earth permanent magnet.

Effect example

The sintered magnets and rare earth permanent magnets in Examples 1-12 and Comparative Examples 1-3 were taken respectively, their magnetic properties and components were measured, and the phase composition of the magnets was observed with EPMA-1720.

(1) The components of the sintered magnets and rare earth permanent magnets of Examples 1 to 12 and Comparative Examples 1 to 4 were measured using a high-frequency inductively coupled plasma emission spectrometer (ICP-OES, Icap6300); Tables 2 and 3 below Shown as component test results. EPMA-1720 was used to detect the grain boundary structure. The rare earth carbides in Table 2 and Table 3 below are distributed in the triple grain boundary, and R-Fe-Cu-C-Ga is distributed in the two-grain boundary.

Formulation (mas%) of sintered magnet of table 2

Note: "/" in the above table means that the element is not contained; "0.23W" in the column "elements distributed on the surface of the main phase grains" means that the content of W is 0.23mas%, that is, the distribution of the main phase grains on the surface has 0.23 mas% W.

The formula (mas%) of table 3 rare earth permanent magnet

Note: "/" in the above table means that the element is not contained; "0.23W" in the column "elements distributed on the surface of the main phase grains" means that the content of W is 0.23mas%, that is, the distribution of the main phase grains on the surface has 0.23 mas% W.

(2) Evaluation of magnetic properties: The magnetic properties of the sintered magnets and rare earth permanent magnets were tested using a PFM-14 magnetic property measuring instrument from Hirst, UK; Table 4 below shows the results of the magnetic property tests.

From Examples 1 to 4 and Comparative Example 1 in Table 4, it can be seen that the Br of the sintered magnets of the present application is all above 14.25kGs, and the coercive force can also be kept above 11.51kOe; after grain boundary diffusion and secondary aging treatment The coercive forces of the rare earth permanent magnets after are all above 23.5kOe, indicating that the sintered magnets of the present application can still maintain good magnetic properties under the premise of higher carbon content;

It can be seen from Example 2 and Comparative Example 3 that, under the premise of not containing Cu, the remanence and coercive force of the sintered magnet and the rare earth permanent magnet both decrease.

From Example 2 and Comparative Example 2, it can be seen that the composition is the same and the carbon content is similar, and under the premise of increasing the carbon content by increasing the amount of antioxidant added, the remanence and coercive force of the sintered magnet and the rare earth permanent magnet are all decreased.

It can be known from Examples 5-10 and Comparative Example 4 that the coercive force of rare earth permanent magnets with low B is above 15.8 kOe, while maintaining high remanence.

It can be seen from Examples 11-12 and Comparative Example 5 that the coercive force of the sintered magnets is all above 25.6 kOe, and at the same time maintains a relatively high remanence.

Table 4 Magnetic properties

Note: "/" in the above table means that it does not contain this element. The rare earth permanent magnets in Examples 1-4 and Comparative Examples 1-3 have undergone diffusion and secondary aging treatment. Examples 5-12 and Comparative Examples 4 and 5 Rare earth permanent magnets are treated with primary and secondary aging.

(3) Determination of microstructure: test the rare earth permanent magnet (as shown in Figure 1) of Example 2 by EPMA-1720, as can be seen from Figure 1, Cr and C distribution positions are completely different, indicating that CrC has decomposed, according to the distribution of C It can be seen from the situation that C and rare earth are distributed at the grain boundary, and mainly distributed at the trifurcation grain boundary. As for Cr, it is distributed on the surface of NdFeB main phase grains.

Claims (10)

1. A material for sintered magnets, characterized in that it includes a first component and a second component, in terms of mass percentage, the first component includes:

   R: 29mas%-33mas%, the R is 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 includes an antioxidant and a refractory carbide including titanium carbide, zirconium carbide, chromium carbide, niobium carbide, tantalum carbide, molybdenum carbide, tungsten carbide, vanadium carbide and hafnium carbide. One or more; the content of the high melting point carbide is 0.1-0.5mas%, and mas% is the mass percentage of each component in the material for sintered magnet.
2. The material for sintered magnets according to claim 1, characterized in that the content of R is 29.5mas% to 32mas%, such as 29.6mas% or 31mas%, and mas% is the proportion of each component in the material for sintered magnets The mass percentage;

   And/or, said R includes PrNd and/or Nd;

   When the R includes PrNd, the content of the PrNd is preferably 0-33mas%, and is not 0, such as 29.5mas% or 31mas%, mas% is the mass of each component in the material for sintered magnets percentage;

   When the R includes Nd, the content of Nd is preferably 0-33mas%, but not 0, such as 29.5mas%, where mas% is the mass percentage of each component in the material for the sintered magnet;

   And/or, the R includes the heavy rare earth element RH; the content of the RH is preferably 0-2.5mas%, and is not 0, and the mas% is the mass percentage of each component in the material for the sintered magnet; The RH preferably includes one or more of Tb, Dy, Ho and Gd; when the RH includes Tb, the content of Tb is preferably 0-0.5mas%, and not 0, For example, 0.1mas%, mas% is the mass percentage of each component in the material for the sintered magnet; when the RH includes Dy, the content of Dy is preferably 0-2.5mas%, and not 0, mas% is the mass percentage of each component in the material for the sintered magnet;

   And/or, the content of B is 0.86mas%-0.99mas%, such as 0.88mas% or 0.95mas%, where mas% is the mass percentage of each component in the material for sintered magnet;

   And/or, the Cu content is 0-0.4mas%, and not 0, such as 0.16mas% or 0.3mas%, where mas% is the mass percentage of each component in the material for sintered magnet;

   And/or, the Ga content is 0.05mas%-0.5mas%, such as 0.25mas%, where mas% is the mass percentage of each component in the material for the sintered magnet;

   And/or, the Fe content is 64.5mas%-69mas%, such as 68.78mas%, 66.72mas% or 64.74mas%, where mas% is the mass percentage of each component in the material for sintered magnet;

   And/or, the antioxidant is magnesium stearate and/or tributyl borate; the content of the antioxidant is preferably 0.05mas%-0.15mas%;

   And/or, the high melting point carbide includes one or more of titanium carbide, zirconium carbide, chromium carbide, niobium carbide, tantalum carbide and tungsten carbide;

   And/or, the content of the high-melting-point carbide is 0.2-0.5mas%, and mas% is the mass percentage of each component in the material for sintered magnet;

   And/or, the first component further includes Co; the content of Co is preferably 0-2mas%, and not 0, more preferably 0-1.6mas%, and not 0, such as 0.5 mas%, mas% is the mass percentage of each component in the material for the sintered magnet;

   And/or, the first component also includes Nb; the content of Nb is preferably 0-0.4mas%, and is not 0, such as 0.1mas%, and mas% is the proportion of each component in the sintered magnet The mass percentage of the material used;

   And/or; the first component also includes Ti; the content of the Ti is preferably 0-0.4mas%, and is not 0, such as 0.18mas%, and mas% is the proportion of each component in the sintered magnet The mass percentage of the material used;

   And/or; the first component also includes Al; the content of the Al is preferably 0-0.5mas%, and not 0, such as 0.3mas%, mas% is the proportion of each component in the sintered magnet The mass percentage of the material used;

   And/or, the first component further includes one or more of Zr, Cr, Ta, Mo, W, V and Hf;

   Alternatively, in terms of mass percentage, the material for sintered magnets is composed of the following components: the first component is: PrNd29.5-33mas%; Dy0-2.5mas% and not 0; B0.95mas%- 1mas%; Cu0.16-0.4mas%; Ga0.05mas%-0.25mas%; Co0.5mas%-1.6mas%; Al0.3mas%-0.5mas%; the second component is ZrC or TiC0. 3mas%～0.5mas%, magnesium stearate 0.05mas%-0.15mas%;

   Alternatively, in terms of mass percentage, the material for the sintered magnet is composed of the following components: the first component is: PrNd29.5-33mas%; B0.86mas%-0.88mas%; Cu0.16-0.4mas% ; Ga0.25mas%-0.5mas%; Co0.5mas%-1.6mas%; the second component is ZrC or TiC0.1mas%-0.5mas%, magnesium stearate 0.05mas%-0.15mas%;

   And/or, in terms of mass percentage, the material for the sintered magnet is composed of the following components: the first component is Nd29.5-33mas%; Tb0.1mas%-0.5mas%; B0.95mas%- 1mas%; Cu0.16～0.4mas%; Ga0.05mas%～0.25mas%; Nb0.1mas%～0.4mas%, Ti0.18mas%～0.4mas%, the second component is, WC, Cr ₃ C ₂ , TaC or NbC, 0.1mas%-0.5mas%, magnesium stearate 0.05mas%-0.15mas%.
3. A sintered magnet, characterized in that, in terms of mass percentage, it comprises the following components:

   R: 29mas%-33mas%, the R is a rare earth element;

   B: 0.86mas%～1mas%;

   M: 0-0.5mas%, and not 0; said M includes one or more of Ti, Zr, Cr, Nb, Ta, Mo, W, V and Hf;

   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 sintered magnet; the sintered magnet includes NdFeB main phase grains, two grain boundaries and triple grain boundaries adjacent to the NdFeB main phase grains, and the triple grain boundaries are distributed Rare earth carbides with fcc structure; all or part of the M elements are distributed on the surface of the NdFeB main phase grains.
4. The sintered magnet according to claim 3, wherein the rare earth carbide is one or more of NdC, PrC, TbC and DyC;

   And/or, the content of R is 29.5mas%-32mas%, such as 29.6mas% or 31mas%, where mas% is the mass percentage of each component in the sintered magnet;

   And/or, said R includes PrNd and/or Nd;

   When the R includes PrNd, the content of the PrNd is preferably 0-33mas%, and not 0, such as 29.5mas% or 31mas%, where mas% is the mass percentage of each component in the sintered magnet;

   When the R includes Nd, the content of Nd is preferably 0-33mas%, but not 0, such as 29.5mas%, where mas% is the mass percentage of each component in the sintered magnet;

   And/or, the R includes the heavy rare earth element RH; preferably, the content of the RH is 0-2.5mas%, and is not 0, and the mas% is the mass percentage of each component in the sintered magnet; relatively Preferably, the RH includes one or more of Tb, Dy, Ho and Gd; when the RH includes Tb, the content of Tb is preferably 0-0.5mas%, and not 0, For example, 0.1mas%, mas% is the mass percentage of each component in the sintered magnet; when the RH includes Dy, the content of Dy is preferably 0-2.5mas%, and not 0, mas% is the mass percentage of each component in the sintered magnet;

   And/or, the content of B is 0.86mas%-0.99mas%, such as 0.88mas% or 0.95mas%, where mas% is the mass percentage of each component in the sintered magnet;

   And/or, the Cu content is 0-0.4mas%, and not 0, such as 0.16mas% or 0.3mas%, where mas% is the mass percentage of each component in the sintered magnet;

   And/or, the Ga content is 0.05mas%-0.5mas%, such as 0.25mas%, where mas% is the mass percentage of each component in the sintered magnet;

   And/or, the Fe content is 64mas%-69mas%, such as 68.4mas%, 66.4mas% or 64.2mas%, where mas% is the mass percentage of each component in the sintered magnet;

   And/or, the content of C is 0.1mas%～0.16mas%, such as 0.155mas%, 0.1178mas%, 0.106mas%, 0.111mas%, 0.1105mas%, 0.128mas%, 0.153mas%, 0.105mas% , 0.124mas%, 0.149mas%, 0.124mas% or 0.1475mas%, mas% is the mass percentage of each component in the sintered magnet;

   And/or, the sintered magnet also includes Al; the content of the Al is preferably 0-0.5mas%, and not 0, such as 0.3mas%, and mas% is the mass of each component in the sintered magnet percentage;

   And/or, the sintered magnet also includes Co; the content of Co is preferably 0-2mas%, and not 0, more preferably 0-1.6mas%, and not 0, such as 0.5mas% , mas% is the mass percentage of each component in the sintered magnet;

   And/or, the M includes one or more of Ti, Nb, Zr, Cr and Ta;

   When the sintered magnet includes Nb, the content of Nb is preferably 0-0.4mas%, and not 0, such as 0.1mas% or 0.32mas%, where mas% is the percentage of each component in the sintered magnet mass percentage;

   When the sintered magnet includes Ti, the content of Ti is preferably 0-0.4mas%, and not 0, such as 0.18mas%, 0.15mas%, 0.25mas%, 0.3mas% or 0.35mas%, mas% is the mass percentage of each component in the sintered magnet;

   When the sintered magnet includes Cr, the Cr content is preferably 0-0.4mas%, and not 0, such as 0.21mas%, where mas% is the mass percentage of each component in the sintered magnet;

   When the sintered magnet includes W, the content of W is preferably 0-0.4mas%, but not 0, such as 0.23mas%, where mas% is the mass percentage of each component in the sintered magnet;

   When the sintered magnet includes Zr, the content of Zr is preferably 0-0.5mas%, and is not 0, such as 0.1mas% or 0.3mas%, and mas% is the percentage of each component in the sintered magnet. mass percentage;

   When the sintered magnet includes Ta, the content of Ta is preferably 0-0.5mas%, and not 0, such as 0.23mas%, where mas% is the mass percentage of each component in the sintered magnet;

   Alternatively, in terms of mass percentage, the sintered magnet is composed of the following components: PrNd 29.5-33mas%; Dy 0-2.5mas% and not 0; B0.95mas%-1mas%; Cu0.16-0.4mas% ; Ga0.05mas% ~ 0.25mas%; Co0.5mas% ~ 1.6mas%; Al0.3mas% ~ 0.5mas%; Ti0 ~ 0.4mas%, and not 0, C0.1mas% ~ 0.16mas%; The sintered magnet includes NdFeB main phase grains, two-grain grain boundaries adjacent to the NdFeB main phase grains, and trifurcated grain boundaries, and the trifurcated grain boundaries are distributed with rare earth carbides of fcc structure; the surface of the NdFeB main phase grains Distributed with said Ti;

   Alternatively, in terms of mass percentage, the sintered magnet is composed of the following components: PrNd 29.5-33mas%; Dy 0-2.5mas% and not 0; B0.95mas%-1mas%; Cu0.16-0.4mas% ; Ga0.05mas% ~ 0.25mas%; Co0.5mas% ~ 1.6mas%; Al0.3mas% ~ 0.5mas%; Zr0 ~ 0.4mas%, and not 0, C0.1mas% ~ 0.16mas%; The sintered magnet includes NdFeB main phase grains, two-grain grain boundaries adjacent to the NdFeB main phase grains, and trifurcated grain boundaries, and the trifurcated grain boundaries are distributed with rare earth carbides of fcc structure; the surface of the NdFeB main phase grains distributed with said Zr;

   Alternatively, in terms of mass percentage, the sintered magnet consists of the following components: PrNd29.5-33mas%; B0.86mas%-0.88mas%; Cu0.16-0.4mas%; Ga0.25mas%-0.5mas%; Co0.5mas% ~ 1.6mas%; Ti0 ~ 0.4mas%, and not 0; the sintered magnet includes NdFeB main phase grains, two grain boundaries and triple grain boundaries adjacent to the NdFeB main phase grains, so Rare earth carbides with an fcc structure are distributed on the trifurcated grain boundaries; the Ti is distributed on the surface of the NdFeB main phase grains;

   Alternatively, in terms of mass percentage, the sintered magnet consists of the following components: PrNd29.5-33mas%; B0.86mas%-0.88mas%; Cu0.16-0.4mas%; Ga0.25mas%-0.5mas%; Co0.5mas%～1.6mas%; Zr0～0.5mas%, and not 0; the sintered magnet includes NdFeB main phase grains, two grain boundaries and triple grain boundaries adjacent to the NdFeB main phase grains, so Rare earth carbides with an fcc structure are distributed on the trifurcated grain boundaries; the Zr is distributed on the surface of the NdFeB main phase grains;

   Alternatively, in terms of mass percentage, the sintered magnet is composed of the following components: Nd29.5-33mas%; Tb0.1mas%-0.5mas%; B0.95mas%-1mas%; Cu0.16-0.4mas%; Ga0 .05mas%～0.25mas%; Nb0.32mas%～0.4mas%, Ti0.18mas%～0.4mas%, the sintered magnet includes NdFeB main phase grains and two grain boundaries adjacent to the NdFeB main phase grains and trifurcated grain boundaries, the trifurcated grain boundaries are distributed with rare earth carbides of fcc structure; the surface of the NdFeB main phase grains is distributed with 0.22mas% Nb elements;

   Alternatively, in terms of mass percentage, the sintered magnet is composed of the following components: Nd29.5-33mas%; Tb0.1mas%-0.5mas%; B0.95mas%-1mas%; Cu0.16-0.4mas%; Ga0 .05mas%～0.25mas%; Nb0.1mas%～0.4mas%, Ti0.18mas%～0.4mas%; Ta0.23～0.5mas%, and not 0; the sintered magnet includes NdFeB main phase grains, Two-grain grain boundaries and trifurcated grain boundaries adjacent to the NdFeB main phase grains, the trifurcated grain boundaries are distributed with rare earth carbides of fcc structure; the surface of the NdFeB main phase grains is distributed with the Ta;

   Alternatively, in terms of mass percentage, the sintered magnet is composed of the following components: Nd29.5-33mas%; Tb0.1mas%-0.5mas%; B0.95mas%-1mas%; Cu0.16-0.4mas%; Ga0 .05mas%～0.25mas%; Nb0.1mas%～0.4mas%, Ti0.18mas%～0.4mas%; Cr0.21～0.4mas%, and not 0; the sintered magnet includes NdFeB main phase grains, Two-grain grain boundaries and trifurcated grain boundaries adjacent to the NdFeB main phase grains, the trifurcated grain boundaries are distributed with rare earth carbides of fcc structure; the surface of the NdFeB main phase grains is distributed with the Cr;

   Alternatively, in terms of mass percentage, the sintered magnet is composed of the following components: Nd29.5-33mas%; Tb0.1mas%-0.5mas%; B0.95mas%-1mas%; Cu0.16-0.4mas%; Ga0 .05mas%～0.25mas%; Nb0.1mas%～0.4mas%, Ti0.18mas%～0.4mas%; W0.23～0.4mas%, and not 0; the sintered magnet includes NdFeB main phase grains, The two-grain grain boundary and the trifurcation grain boundary adjacent to the NdFeB main phase grain, the trifurcation grain boundary is distributed with rare earth carbides of fcc structure; the surface of the NdFeB main phase grain is distributed with the W.
5. A rare earth permanent magnet is characterized in that, in terms of mass percentage, it comprises the following components:

   R: 29mas%-33mas%, the R is a rare earth element;

   B: 0.86mas%～1mas%;

   M: 0-0.5mas%, and not 0; said M includes one or more of Ti, Zr, Cr, Nb, Ta, Mo, W, V and Hf;

   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 grain boundaries and three-pronged grain boundaries adjacent to the NdFeB main phase grains, and the three-pronged grains The rare earth carbide with hcp structure is distributed in the boundary; the RE-Cu-Fe-C-Ga phase is distributed in the grain boundary of the two particles;

   All or part of the M elements are distributed on the surface of the NdFeB main phase grains.
6. The rare earth permanent magnet according to claim 5, wherein the rare earth carbide is one or more of NdC, PrC, TbC and DyC;

   And/or, the trifurcation grain boundary is also distributed with Nd ₆ (FeGa) _14;

   And/or, the content of R is 29.5mas%-32mas%, such as 29.6mas% or 31mas%, and mas% is the mass percentage of each component in the rare earth permanent magnet;

   And/or, said R includes PrNd and/or Nd;

   When the R includes PrNd, the content of the PrNd is preferably 0-33mas%, and is not 0, such as 29.5mas% or 31mas%, and mas% is the mass percentage of each component in the rare earth permanent magnet ;

   When the R includes Nd, the content of Nd is preferably 0-33mas%, and not 0, such as 29.5mas%, where mas% is the mass percentage of each component in the rare earth permanent magnet;

   And/or, the R includes the heavy rare earth element RH; preferably, the content of the RH is 0-2.5mas%, and is not 0, and the mas% is the mass percentage of each component in the rare earth permanent magnet; Preferably, the RH includes one or more of Tb, Dy, Ho and Gd; when the RH includes Tb, the content of Tb is preferably 0-0.5mas%, and not 0 , such as 0.1mas%, mas% is the mass percentage of each component in the rare earth permanent magnet; when the RH includes Dy, the content of Dy is preferably 0-2.5mas%, and not 0, mas% is the mass percent of each component accounting for the rare earth permanent magnet;

   And/or, the content of B is 0.86mas%～0.99mas%, such as 0.88mas% or 0.95mas%, mas% is the mass percentage of each component in the rare earth permanent magnet;

   And/or, the Cu content is 0-0.4mas%, and not 0, such as 0.16mas% or 0.3mas%, where mas% is the mass percentage of each component in the rare earth permanent magnet;

   And/or, the Ga content is 0.05mas%-0.5mas%, such as 0.25mas%, where mas% is the mass percentage of each component in the rare earth permanent magnet;

   And/or, the Fe content is 64mas%-69mas%, such as 68.4mas%, 66.4mas% or 64.2mas%, where 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%, such as 0.155mas%, 0.1178mas%, 0.106mas%, 0.111mas%, 0.1105mas%, 0.128mas%, 0.153mas%, 0.105mas% , 0.124mas%, 0.149mas%, 0.124mas% or 0.1475mas%, mas% is the mass percentage of each component in the rare earth permanent magnet;

   And/or, the rare earth permanent magnet also includes Al; the content of the Al is preferably 0-0.5mas%, and is not 0, such as 0.3mas%, and mas% is the proportion of each component in the rare earth permanent magnet. The mass percentage;

   And/or, the rare earth permanent magnet also includes Co; the content of Co is preferably 0-2mas%, and not 0, more preferably 0-1.6mas%, and not 0, for example, 0.5mas %, mas% is the mass percentage of each component in the rare earth permanent magnet;

   And/or, the M includes one or more of Ti, Nb, Zr, Cr and Ta;

   When the rare earth permanent magnet includes Nb, the content of Nb is preferably 0-0.4mas%, and not 0, such as 0.1mas% or 0.32mas%, and mas% is the proportion of each component in the rare earth permanent magnet. The mass percentage of the magnet;

   When the rare earth permanent magnet includes Ti, the content of Ti is preferably 0-0.4mas%, and not 0, such as 0.18mas%, 0.15mas%, 0.25mas%, 0.3mas% or 0.35mas%. , mas% is the mass percentage of each component in the rare earth permanent magnet;

   When the rare-earth permanent magnet includes Cr, the content of the Cr is preferably 0-0.4mas%, and not 0, such as 0.21mas%, and mas% is the mass percentage of each component in the rare-earth permanent magnet ;

   When the rare earth permanent magnet includes W, the content of W is preferably 0-0.4mas%, and not 0, such as 0.23mas%, where mas% is the mass percentage of each component in the rare earth permanent magnet ;

   When the rare earth permanent magnet includes Zr, the content of Zr is preferably 0 to 0.5mas%, and is not 0, such as 0.1mas% or 0.3mas%, and mas% is the proportion of each component in the rare earth permanent magnet. The mass percentage of the magnet;

   When the rare earth permanent magnet includes Ta, the content of Ta is preferably 0-0.5mas%, and not 0, such as 0.23mas%, where mas% is the mass percentage of each component in the rare earth permanent magnet ;

   And/or, in terms of mass percentage, the rare earth permanent magnet is composed of the following components: PrNd 29.5-33mas%; Dy 0-2.5mas% and not 0; B0.95mas%-1mas%; Cu0.16- 0.4mas%; Ga0.05mas% ~ 0.25mas%; Co0.5mas% ~ 1.6mas%; Al0.3mas% ~ 0.5mas%; Ti0 ~ 0.4mas%, and not 0, C0.1mas% ~ 0.16mas% ; The rare earth permanent magnet includes NdFeB main phase grains, two grain boundaries adjacent to the NdFeB main phase grains, and a trifurcation grain boundary, and the trifurcation grain boundaries are distributed with rare earth carbides of hcp structure; the two grain grains The RE-Cu-Fe-C-Ga phase is distributed on the boundary; the Ti is distributed on the surface of the NdFeB main phase grain;

   And/or, in terms of mass percentage, the rare earth permanent magnet is composed of the following components: PrNd 29.5-33mas%; Dy 0-2.5mas% and not 0; B0.95mas%-1mas%; Cu0.16- 0.4mas%; Ga0.05mas% ~ 0.25mas%; Co0.5mas% ~ 1.6mas%; Al0.3mas% ~ 0.5mas%; Zr0 ~ 0.4mas%, and not 0, C0.1mas% ~ 0.16mas% ; The rare earth permanent magnet includes NdFeB main phase grains, two grain boundaries adjacent to the NdFeB main phase grains, and a trifurcation grain boundary, and the trifurcation grain boundaries are distributed with rare earth carbides of hcp structure; the two grain grains The RE-Cu-Fe-C-Ga phase is distributed on the boundary; the Zr is distributed on the surface of the NdFeB main phase grain;

   And/or, in terms of mass percentage, the rare earth permanent magnet is composed of the following components: PrNd29.5-33mas%; B0.86mas%-0.88mas%; Cu0.16-0.4mas%; Ga0.25mas%-0.5 mas%; Co0.5mas% ~ 1.6mas%; Ti0 ~ 0.4mas%, and not 0; the rare earth permanent magnet includes NdFeB main phase grains, two grain boundaries adjacent to the NdFeB main phase grains and three fork The grain boundary, the rare earth carbide of the hcp structure is distributed in the trifurcated grain boundary; the RE-Cu-Fe-C-Ga phase is distributed in the two-grain grain boundary; the surface of the NdFeB main phase grain is distributed with the Ti;

   And/or, in terms of mass percentage, the rare earth permanent magnet is composed of the following components: PrNd29.5-33mas%; B0.86mas%-0.88mas%; Cu0.16-0.4mas%; Ga0.25mas%-0.5 mas%; Co0.5mas% ~ 1.6mas%; Zr0 ~ 0.5mas%, and not 0; the rare earth permanent magnet includes NdFeB main phase grains, two grain boundaries adjacent to the NdFeB main phase grains and three forks The grain boundary, the rare earth carbide of the hcp structure is distributed in the trifurcated grain boundary; the RE-Cu-Fe-C-Ga phase is distributed in the two-grain grain boundary; the surface of the NdFeB main phase grain is distributed with the Zr;

   And/or, in terms of mass percentage, the rare earth permanent magnet is composed of the following components: Nd29.5-33mas%; Tb0.1mas%-0.5mas%; B0.95mas%-1mas%; Cu0.16-0.4mas% %; Ga0.05mas% ~ 0.25mas%; Nb0.32mas% ~ 0.4mas%, Ti0.18mas% ~ 0.4mas%, the rare earth permanent magnet includes NdFeB main phase grains, adjacent to the NdFeB main phase grains The two-grain boundary and the three-pronged grain boundary, the three-pronged grain boundary is distributed with rare earth carbides of hcp structure; the two-particle grain boundary is distributed with RE-Cu-Fe-C-Ga phase; the NdFeB main phase grain The surface distribution has 0.22mas% Nb element;

   And/or, in terms of mass percentage, the rare earth permanent magnet is composed of the following components: Nd29.5-33mas%; Tb0.1mas%-0.5mas%; B0.95mas%-1mas%; Cu0.16-0.4mas% %; Ga0.05mas% ~ 0.25mas%; Nb0.1mas% ~ 0.4mas%, Ti0.18mas% ~ 0.4mas%; Ta0.23 ~ 0.5mas%, and not 0; the rare earth permanent magnet includes NdFeB main Phase grains, two-grain boundaries and three-pronged grain boundaries adjacent to the NdFeB main phase grains, the three-pronged grain boundaries are distributed with rare earth carbides of hcp structure; 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 Ta;

   And/or, in terms of mass percentage, the rare earth permanent magnet is composed of the following components: Nd29.5-33mas%; Tb0.1mas%-0.5mas%; B0.95mas%-1mas%; Cu0.16-0.4mas% %; Ga0.05mas% ~ 0.25mas%; Nb0.1mas% ~ 0.4mas%, Ti0.18mas% ~ 0.4mas%; Cr0.21 ~ 0.4mas%, and not 0; the rare earth permanent magnet includes NdFeB main Phase grains, two-grain boundaries and three-pronged grain boundaries adjacent to the NdFeB main phase grains, the three-pronged grain boundaries are distributed with rare earth carbides of hcp structure; 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 Cr;

   And/or, in terms of mass percentage, the rare earth permanent magnet is composed of the following components: Nd29.5-33mas%; Tb0.1mas%-0.5mas%; B0.95mas%-1mas%; Cu0.16-0.4mas% %; Ga0.05mas% ~ 0.25mas%; Nb0.1mas% ~ 0.4mas%, Ti0.18mas% ~ 0.4mas%; W0.23 ~ 0.4mas%, and not 0; the rare earth permanent magnet includes NdFeB main Phase grains, two-grain boundaries and three-pronged grain boundaries adjacent to the NdFeB main phase grains, the three-pronged grain boundaries are distributed with rare earth carbides of hcp structure; the two-particle grain boundaries are distributed with RE-Cu-Fe- C—Ga phase; the W is distributed on the surface of the NdFeB main phase grains.
7. A method for preparing a sintered magnet, characterized in that the method comprises the following steps: smelting and coarsely pulverizing the first component in the material for a sintered magnet according to claim 1 or 2, to obtain Coarse powder;

   Finely pulverize the mixture of the coarse powder and 40%-60% of the antioxidant to obtain a fine powder;

   Then, the mixture of the fine powder and the remaining second component is formed and sintered.
8. The method for preparing a sintered magnet according to claim 7, characterized in that the melting temperature is 1300-1700°C, such as 1500°C;

   And/or, the melting equipment is a high-frequency vacuum melting furnace and/or an intermediate frequency vacuum melting furnace;

   And/or, the coarse crushing is hydrogen crushing;

   The hydrogen crushing preferably includes hydrogen absorption, dehydrogenation and cooling treatment; the temperature of the hydrogen absorption is preferably 20-200°C, more preferably 20-40°C; the pressure of the hydrogen absorption is preferably 50-600kPa, such as 90kPa; the dehydrogenation temperature is preferably 400-650°C, such as 550°C;

   And/or, the fine pulverization is jet milling powder;

   The pressure of the jet milling powder is preferably 0.1-2MPa, more preferably 0.5-0.7MPa, such as 0.65MPa;

   And/or, the sintering temperature is 1000-1200°C, preferably 1030-1090°C;

   And/or, the sintering time is 0.5-10 hours, preferably 2-8 hours.
9. A preparation method of a rare earth permanent magnet, characterized in that the preparation method comprises the steps of: making the sintered magnet according to claim 3 or 4 through one of the following two methods:

   Method 1: After the first-level aging treatment and the second-level aging treatment in sequence;

   Method 2: sequentially undergo grain boundary diffusion treatment and secondary aging treatment;

   In way one, the temperature of the primary aging treatment is preferably 880°C-920°C, for example 900°C;

   In way 1, the time for the first-stage aging is preferably 2h-4h, for example 2h;

   In mode 2, the heavy rare earth elements in the grain boundary diffusion treatment preferably include Tb and/or Dy;

   In method 2, the grain boundary diffusion treatment is preferably: depositing, coating or sputtering a substance containing Tb or a substance containing Dy on the surface of the sintered magnet, and then undergoing diffusion heat treatment;

   Wherein, the substance containing Tb or Dy is preferably Tb or Dy metal, a compound or alloy containing Tb or Dy;

   Wherein, the temperature of the grain boundary diffusion treatment is preferably 800-900°C, such as 850°C;

   Wherein, the time for the grain boundary diffusion treatment is preferably 12-48 hours, such as 24 hours;

   In mode 1 and/or mode 2, the temperature of the secondary aging treatment is preferably 460°C-520°C, for example 490°C;

   In mode 1 and/or mode 2, the time for the secondary aging is preferably 2h-4h, for example 2h.
10. An application of the sintered magnet as claimed in claim 3 or 4 and/or the rare earth permanent magnet as claimed in claim 5 or 6 as a permanent magnet motor rotor.

Images