CN115083715A - Heterogeneous single crystal magnetic powder and preparation method and application thereof - Google Patents
Heterogeneous single crystal magnetic powder and preparation method and application thereof Download PDFInfo
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- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims abstract description 8
- 238000004880 explosion Methods 0.000 claims abstract description 8
- 239000001257 hydrogen Substances 0.000 claims abstract description 8
- 229910052739 hydrogen Inorganic materials 0.000 claims abstract description 8
- 238000002156 mixing Methods 0.000 claims abstract description 7
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- 239000010949 copper Substances 0.000 claims description 23
- 229910052761 rare earth metal Inorganic materials 0.000 claims description 22
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- 229910052802 copper Inorganic materials 0.000 claims description 13
- 238000005266 casting Methods 0.000 claims description 12
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- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 7
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- 230000006698 induction Effects 0.000 claims description 6
- 238000003723 Smelting Methods 0.000 claims description 5
- 229910052786 argon Inorganic materials 0.000 claims description 5
- 238000005121 nitriding Methods 0.000 claims description 5
- 238000010791 quenching Methods 0.000 claims description 5
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- 229910052735 hafnium Inorganic materials 0.000 claims description 2
- 239000012535 impurity Substances 0.000 claims description 2
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- 230000008018 melting Effects 0.000 abstract description 6
- 229910052772 Samarium Inorganic materials 0.000 abstract description 3
- 238000006243 chemical reaction Methods 0.000 abstract description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 22
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- 229910001172 neodymium magnet Inorganic materials 0.000 description 4
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- PRQMIVBGRIUJHV-UHFFFAOYSA-N [N].[Fe].[Sm] Chemical compound [N].[Fe].[Sm] PRQMIVBGRIUJHV-UHFFFAOYSA-N 0.000 description 2
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Classifications
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
- H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
- H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
- H01F1/032—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials
- H01F1/04—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials metals or alloys
- H01F1/047—Alloys characterised by their composition
- H01F1/053—Alloys characterised by their composition containing rare earth metals
- H01F1/055—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5
- H01F1/059—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and Va elements, e.g. Sm2Fe17N2
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
- H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
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- Chemical & Material Sciences (AREA)
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Abstract
The invention discloses heterogeneous single crystal magnetic powder and a preparation method and application thereof. A method for preparing heterogeneous single crystal magnetic powder comprises the following steps: La/Ce/Y-rich (Sm, R1) having a particle size of 1-20 μm 2 Fe 17 Taking alloy powder as mother alloy magnetic powder, mixing Sm diffusion source alloy powder with a volatile organic solvent to form a paste, uniformly mixing the mother alloy magnetic powder with the paste to obtain a mixture, wherein the mass ratio of the mother alloy magnetic powder to the diffusion source alloy powder is 88:12-97:3, and then sequentially carrying out diffusion heat treatment, hydrogen explosion treatment, dehydrogenation treatment, powder preparation and nitridation on the mixture to obtain the heterogeneous single crystal magnetic powder. The invention takes low melting point alloy as a diffusion source of Sm, Sm is evaporated on the surface of La/Ce/Y-rich single crystal magnetic powder through heat treatment, then a Sm-rich thin shell layer is formed on the surface of the La/Ce/Y-rich single crystal magnetic powder through low-temperature diffusion reaction, and the heterogeneous single crystal magnetic powder is nitrided into La/Ce/Y-rich anisotropic single crystal magnetic powder with high coercivityPermanent magnetic powder.
Description
The technical field is as follows:
the invention relates to a rare earth permanent magnet material, in particular to heterogeneous single crystal magnetic powder and a preparation method and application thereof.
The background art comprises the following steps:
the sintered Nd-Fe-B permanent magnet invented by the Sumitomo special metal Kawawa (Masato Sagawa) in 1982 is the most widely used rare earth permanent magnet at present because of the highest magnetic energy product, high coercive force, low cost of raw materials and simple preparation method. The bonded magnet prepared by using the rapidly quenched Nd-Fe-B magnetic powder invented by general electric company is widely accepted by the market because of high dimensional precision and convenience in preparing special-shaped magnets. Rare earth permanent magnets become important basic materials in modern society, and are widely applied to industries such as computers, automobiles, instruments, household appliances, petrochemical industry, medical care, aerospace and the like.
The research group of Coey professor of three university of Ireland and the research group of Yang Yichang university of Beijing in 1990 found Sm based on the interstitial effect of nitrogen in rare earth-transition metal compounds 2 Fe 17 N x Samarium iron Nitrogen for short and Nd (Fe, M) 12 N x (neodymium iron nitrogen for short) has excellent intrinsic magnetism, comparable to neodymium iron boron, and has higher curie temperature than neodymium iron boron, and samarium iron nitrogen and neodymium iron nitrogen are considered as candidates for the next generation of rare earth permanent magnets.
Known as Sm 2 Fe 17 N 3 The compound has huge magnetocrystalline anisotropy field when Sm is 2 Fe 17 N 3 The single crystal magnetic powder has higher coercive force when the particle size is 3 mu m. Sm belongs to a scarce resource, the global yield is limited, and if Sm is produced in large quantities 2 Fe 17 N 3 The permanent magnetic material will cause the shortage of Sm element supply. And the rare earth elements such as La, Ce, Y and the like are abundant in a large amount, so that the price is low. Known Sm 2 Fe 17 N 3 When less than 85% of Sm element in the compound is substituted by other rare earth elements, the compound still keeps easy c-axis magnetization and still keeps high magnetization intensity, and onlyIt is the magnetocrystalline anisotropy field that decreases dramatically with increasing substitution. The coercive force of the magnetic powder is closely related to the magnetocrystalline anisotropy field of the compound, and the coercive force of the magnetic powder is inevitably reduced greatly along with the increase of the substitution amount. Therefore, the problem of Sm resource shortage is difficult to solve by simply replacing high-abundance elements such as La, Ce, Y and the like.
The invention content is as follows:
in order to solve the problems in the prior art, the invention provides a heterogeneous single crystal magnetic powder and a preparation method and application thereof.
Because the magnetocrystalline anisotropy field of the shell layer on the surface of the magnetic powder is an important factor for determining the coercive force of the magnetic powder, the Sm-rich thin shell layer is formed on the Sn-poor single crystal magnetic powder, so that Sm can be greatly replaced, the coercive force of the magnetic powder can be greatly improved through the Sm-rich shell layer on the surface of the magnetic powder, and the Sm can be replaced by abundant elements such as La, Ce and Y, so that the problem of Sm resource shortage is solved.
It is a first object of the present invention to provide an Sm diffusion source alloy having a composition, expressed in atomic percent, of Sm d M1 100-d D is more than or equal to 50 and less than or equal to 95, and M1 is Cu and/or Zn.
The second purpose of the invention is to provide a preparation method of the Sm diffusion source alloy, which comprises the following steps: and (3) induction-smelting Sm and M1 alloy under the protection of argon to obtain a melt, preparing a rapid quenching diffusion source alloy thin strip by using a water-cooled copper roller with the speed of 10-50M/s, and grinding the rapid quenching diffusion source alloy thin strip into particles with the particle size of 10-500 mu M to obtain Sm diffusion source alloy powder.
The melting point of the prepared diffusion source alloy thin strip is lower than 960 ℃. And grinding the rapid quenching belt into particles of 10-500 mu m by using an air flow mill or a ball mill to obtain the diffusion source alloy powder.
The third purpose of the invention is to provide the preparation of the inhomogeneous single crystal magnetic powderThe method comprises the following steps: La/Ce/Y-rich (Sm, R1) having a particle size of 1-20 μm 2 Fe 17 Taking alloy powder as mother alloy magnetic powder, mixing the Sm diffusion source alloy powder with a volatile organic solvent to form a paste, uniformly mixing the mother alloy magnetic powder with the paste to obtain a mixture, wherein the mass ratio of the mother alloy magnetic powder to the diffusion source alloy powder is 88:12-97:3, and then sequentially carrying out diffusion heat treatment, hydrogen explosion treatment, dehydrogenation treatment, powder preparation and nitridation on the mixture to obtain the heterogeneous single crystal magnetic powder. The organic solvent is preferably absolute ethanol. The mass ratio of the master alloy magnetic powder to the diffusion source alloy powder is preferably 95:5 to 91: 9.
The invention is rich in La/Ce/Y (Sm, R) 2 Fe 17 Forming Sm-rich shell on the grain, the shell having a structure of 2:17, namely forming (Sm, R) with Sm-rich shell 2 Fe 17 Inhomogeneous single crystal magnetic powder.
Preferably, said La/Ce/Y-rich (Sm, R1) 2 Fe 17 The composition of the alloy powder is expressed by atomic percent as: (Sm) 1-α R1 α ) b Fe 100-b-c M2 c Wherein R1 is at least one rare earth element other than Sm, 0.2<α<1；9<b<13; m2 is at least one of Co, Si, Ga, Al, Ni, Ti, Cu, V, Cr, Zr, Hf, Nb, Ta, Mo and W, and c is more than or equal to 0 and less than or equal to 30.
Further preferably, R1 is selected from at least one of La, Ce and Y.
Preferably, the preparation steps of the master alloy magnetic powder are as follows: according to (Sm) 1-α R1 α ) b Fe 100-b-c M2 c The preparation method comprises the steps of preparing materials, adding 10% of Sm which is easy to volatilize on the basis of a theoretical value as compensation, putting prepared metals of Sm, pure Fe, R1 and M2 into an induction smelting furnace to be smelted in high-purity Ar, using induction to heat alloy until the raw materials are completely and uniformly melted to obtain a melt, preparing the melt into a rapid-solidification cast sheet at a water-cooling copper roll speed, placing the master alloy cast sheet into a heat treatment container, carrying out heat treatment under the protection of argon, and crushing the master alloy cast sheet into master alloy magnetic powder with average particles of 1-20 mu M after air cooling.
Preferably, the linear speed of the surface of the water-cooling copper roller is 10-30m/s, the heat treatment temperature is 900-1000 ℃, and the heat treatment time is 30-50 min.
Preferably, the specific steps of sequentially carrying out diffusion heat treatment, hydrogen explosion treatment, dehydrogenation treatment, pulverization and nitridation on the mixture to obtain the heterogeneous single crystal magnetic powder are as follows: placing the mixture in a vacuum furnace under the protection of high-purity Ar for diffusion heat treatment, wherein the temperature of the diffusion heat treatment is 650-960 ℃, and the time of the heat treatment is 0.5-10 h; placing the casting sheet after diffusion heat treatment in H at 150-250 deg.C 2 Carrying out medium treatment for 1-3h, carrying out hydrogen explosion treatment, adjusting the furnace temperature to 550-600 ℃, and carrying out vacuum-pumping dehydrogenation treatment for 1.5-2.5 h; and grinding the casting sheet subjected to dehydrogenation treatment to obtain magnetic powder, and nitriding the magnetic powder for 30-40h at 400-450 ℃ by using high-purity nitrogen to obtain heterogeneous single crystal magnetic powder.
The method comprises the following specific steps of grinding the casting sheet subjected to dehydrogenation treatment to obtain magnetic powder: and (3) grinding the cast sheet subjected to dehydrogenation by using a low-energy ball mill by using 6mm stainless steel balls, wherein the ball-material ratio is 5:1, the rotating speed of a planetary ball mill is set to be 150rpm, and the grinding time is 2 h.
The purpose of diffusion heat treatment of the mixed material is to volatilize Sm from the low melting point diffusion source and combine it with the master alloy powder to form a Sm-rich phase, which in the subsequent heat treatment is Sm-rich and La/Ce/Y-rich (Sm, R1) 2 Fe 17 Inter-granular diffusion occurs and a Sm-rich shell is formed. Having Sm rich shell (Sm, R1) 2 Fe 17 The crystal grains have a surface layer with a high magnetocrystalline anisotropy field after nitridation, and the coercive force of the magnetic powder is improved.
Preferably, the heterogeneous single crystal magnetic powder consists of a first phase, a second phase and a third phase, wherein the first phase consists of rare earth elements Sm, R1, Fe and transition metal element M2 and has Th 2 Zn 17 Or Th 2 Ni 17 The main phase of the type structure, the crystal grain of the main phase has a spherical or equiaxed shape and has a Sm-rich shell layer, namely the Sm/(Sm, R1) atomic content ratio in the range of 0.15 mu m thickness of the surface layer is higher than that of the central part of the crystal grain by more than 20 percent, and the Sm-rich shell layer thickness is between 0.1 and 1.0 mu m; the main phase constituent atoms account for 80-99% of the parent alloy atoms; the second kind of phase isThe rare earth-rich auxiliary phase, the constituent atoms of which account for 0.5-19% of the master alloy, is composed of (Sm, R1) (Fe, M2) 2 、(Sm，R1)(Fe，M2)T 3 、(Sm，R1)(Fe，M2)M1、(Sm，R1)M1 2 Any three of the phases, the third phase is an oxide or nitride of rare earth Sm, R1 and other unavoidable impurities.
The invention also protects the application of the heterogeneous single crystal magnetic powder in the preparation of anisotropic bonded permanent magnet materials or sintered anisotropic permanent magnet materials.
Compared with the prior art, the invention has the following advantages: the diffusion source is composed of Sm-M1 alloy with low melting point, is easy to melt and promotes the volatilization of Sm element during heat treatment, so that the Sm element is convenient to uniformly react with the surfaces of mother alloy powder particles and form a rare earth-rich auxiliary phase, and the beneficial element Sm is diffused into main phase crystal grains at lower temperature and forms an Sm-rich shell layer. In addition, after the rare earth-rich auxiliary phase is formed on the surface of the main phase crystal grains, the rare earth-rich auxiliary phase with a lower melting point can promote the migration of atoms on the surface of the particles, promote the spheroidization of the powder particles, and form the crystal grains with a spherical or equiaxed appearance. Under the preferable conditions, the angular master alloy powder can be spheroidized at the temperature lower than 850 ℃ after a low-melting point diffusion source is added. The spheroidized crystal grains have lower demagnetization factors, and are beneficial to obtaining higher coercive force. In addition, anisotropic magnetic powder particles having a spherical shape more easily attain a high degree of orientation at the time of injection molding.
The specific implementation mode is as follows:
the following is a further description of the invention and is not intended to be limiting.
Example 1
A method for preparing heterogeneous single crystal magnetic powder comprises the following steps:
(1) rare earth Sm, Ce, pure Fe and pure Cu with the purity of 99.9 percent are used as raw materials, and the raw materials are mixed according to the following chemical formula: (Sm) 0.2 Ce 0.8 ) 11.58 Fe 87.42 Nb 1 Cu 1.00 (at%). Since Sm is easy to volatilize, 10% more is added as compensation on the basis of the theoretical value. Mixing the prepared metals Sm,Putting pure Fe, Ce and Cu raw materials into an induction melting furnace to be melted in high-purity Ar. And (3) heating the alloy by induction until the raw materials are completely and uniformly melted, wherein the temperature of the melt is about 1490 ℃, and preparing the rapid-hardening casting sheet by using the water-cooled copper roller speed, wherein the linear speed of the surface of the copper roller is 10 m/s. And (3) placing the casting sheet in a corundum crucible, carrying out heat treatment for 40min under the protection of argon at 950 ℃, and cooling in air. The master alloy cast piece was crushed into master alloy magnetic powder having an average particle size of 3 μm using a ball mill.
(2) The diffusion source alloy comprises Sm 50 Cu 50 The fast quenched thin strip is prepared by water cooling copper roll speed, and the linear speed of the surface of the copper roll is 30 m/s. And grinding the thin strip into powder in a ball milling tank under the protection of Ar, wherein the average particle size is 30 mu m, and thus, the diffusion source alloy powder is obtained.
(3) Adding the diffusion source alloy powder into absolute ethyl alcohol according to the volume ratio of the diffusion source alloy powder to the absolute ethyl alcohol of 1:2 to mix into a paste. The paste and the master alloy magnetic powder are uniformly mixed, and the diffusion source alloy powder accounts for 3-12 wt% of the total mass of the diffusion source alloy powder and the master alloy magnetic powder (specifically, as shown in table 1). And placing the uniformly mixed mixture in a vacuum furnace under the protection of high-purity Ar for diffusion heat treatment. The heat treatment temperature is 900 ℃, and the heat treatment time is 1.2 h. Placing the casting sheet subjected to diffusion heat treatment at 200 deg.C in H 2 And (5) performing intermediate treatment for 2h, and performing hydrogen explosion treatment. The furnace temperature is adjusted to 580 ℃, and the vacuum-pumping dehydrogenation treatment is carried out for 2 hours. And (3) carrying out low-energy ball milling on the casting piece subjected to dehydrogenation treatment by using 6mm stainless steel balls, wherein the ball-material ratio is 5:1, the rotating speed of a planetary ball mill is set to be 150rpm, and the milling time is 2 h. The magnetic powder was nitrided using high-purity nitrogen gas at 430 ℃ for 35 hours, and nitrided by gas-solid reaction. The magnetic powder and the thermal paraffin were mixed in proportion, and after orientation by a magnetic field, the oriented sample was tested using a vibrating magnetometer (VSM). The direction of the loading magnetic field is parallel to the easy magnetization axis of the sample. Magnetic properties of the magnetic powder samples are shown in table 1 below:
TABLE 1 diffusion source alloy composition Sm 50 Cu 50 Magnetic performance test meter for nitriding magnetic powder during alloying
| Diffusion source alloy content (wt%) | Magnetic powder particle size (mum) | Surface layer Ce/(Sm + Ce) ratio | B r (T) | H cj (kOe) | (BH) max (MGOe) |
| 0 | 3.0 | 0.80 | 0.71 | 1.1 | 2.3 |
| 3 | 3.0 | 0.41 | 1.26 | 3.8 | 14.6 |
| 5 | 3.0 | 0.38 | 1.24 | 4.6 | 21.5 |
| 7 | 3.0 | 0.32 | 1.22 | 5.7 | 25.4 |
| 9 | 3.0 | 0.27 | 1.20 | 6.6 | 28.6 |
| 12 | 3.0 | 0.22 | 1.17 | 7.2 | 22.4 |
From table 1, with the increase of the diffusion source alloy powder, the Sm content in the surface layer of the prepared nitrided magnetic powder is increased and the Ce content is reduced, so that the coercive force and the magnetic energy product of the magnetic powder are both obviously improved, and the magnetic performance is obviously superior to that of the original powder without diffusion heat treatment.
Example 2
The same as example 1, except that: the diffusion source alloy comprises Sm 70 Cu 30 The magnetic properties of the alloy and magnetic powder samples are shown in Table 2 below:
TABLE 2 diffusion source alloy composition Sm 70 Cu 30 Magnetic performance test meter for nitriding magnetic powder during alloying
| Diffusion source alloy content (wt%) | Magnetic powder particle size (mum) | Surface layer Ce/(Sm + Ce) ratio | B r (T) | H cj (kOe) | (BH) max (MGOe) |
| 0 | 3.0 | 0.80 | 0.7 | 1.1 | 2.3 |
| 3 | 3.0 | 0.35 | 1.26 | 4.9 | 16.6 |
| 5 | 3.0 | 0.27 | 1.22 | 6.7 | 23.4 |
| 7 | 3.0 | 0.25 | 1.19 | 6.9 | 28.6 |
| 9 | 3.0 | 0.23 | 1.16 | 7.2 | 26.7 |
| 12 | 3.0 | 0.19 | 1.11 | 7.8 | 25.4 |
From table 2, with the increase of the diffusion source alloy powder, the Sm content in the surface layer of the prepared nitrided magnetic powder is increased and the Ce content is reduced, so that the coercive force and the magnetic energy product of the magnetic powder are both obviously improved, and the magnetic performance is obviously superior to that of the original powder without diffusion heat treatment.
Example 3
The same as example 1, except that: the diffusion source alloy comprises Sm 95 Cu 5 The magnetic properties of the alloy and magnetic powder samples are shown in the following table 3:
TABLE 3 diffusion Source is Sm 95 Cu 5 Magnetic performance test meter for nitriding magnetic powder during alloying
| Diffusion source alloy content (wt%) | Magnetic powder particle size (mum) | Surface layer Ce/(Sm + Ce) ratio | B r (T) | H cj (kOe) | (BH) max (MGOe) |
| 0 | 3.0 | 0.80 | 0.7 | 1.1 | 2.3 |
| 3 | 3.0 | 0.36 | 1.17 | 4.9 | 16.8 |
| 5 | 3.0 | 0.29 | 1.08 | 6.9 | 23.5 |
| 7 | 3.0 | 0.24 | 0.98 | 7.2 | 18.8 |
| 9 | 3.0 | 0.20 | 0.91 | 7.6 | 15.4 |
| 12 | 3.0 | 0.16 | 0.77 | 8.4 | 10.3 |
From table 3, with the increase of the diffusion source alloy powder, the Sm content in the surface layer of the prepared nitrided magnetic powder is increased and the Ce content is reduced, so that the coercive force and the magnetic energy product of the magnetic powder are both obviously improved, and the magnetic performance is obviously superior to that of the original powder without diffusion heat treatment.
Sm 2 Fe 17 N 3 When less than 85% of Sm element in the compound is substituted by other rare earth elements such as La, Ce and Y, the compound still keeps easy c-axis magnetization and still keeps high magnetization intensity, but the magnetocrystalline anisotropy field is greatly reduced along with the increase of the substituted amount. The coercive force of the magnetic powder is closely related to the magnetocrystalline anisotropy field of the compound, and the coercive force of the magnetic powder is inevitably reduced greatly along with the increase of the substitution amount. According to the invention, by adding the Sm diffusion source and a heat treatment method, the Sm content of the shell layer of the single crystal magnetic powder is effectively improved, and the Ce content is reduced, so that the magnetocrystalline anisotropy field on the surface of the magnetic powder is effectively improved, the coercive force of the magnetic powder is effectively improved, and the magnetic energy product is also effectively improved along with the improvement of the demagnetization resistance capability of the magnetic powder. The method is suitable for alloy with different Sm ratio substituted by other rare earth elements such as La, Ce and Y.
The above embodiments are only for the purpose of helping understanding the technical solution of the present invention and the core idea thereof, and it should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principle of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.
Claims (10)
1. An Sm diffusion source alloy characterized in that the component expressed in atomic percent is Sm d M1 100-d D is more than or equal to 50 and less than or equal to 95, and M1 is Cu and/or Zn.
2. The method of making an Sm diffusion source alloy as claimed in claim 1, comprising the steps of: and (3) induction-smelting Sm and M1 alloy under the protection of argon to obtain a melt, preparing a rapid quenching diffusion source alloy thin strip by using a water-cooled copper roller with the speed of 10-50M/s, and grinding the rapid quenching diffusion source alloy thin strip into particles with the particle size of 10-500 mu M to obtain Sm diffusion source alloy powder.
3. A method for preparing heterogeneous single crystal magnetic powder is characterized by comprising the following steps: La/Ce/Y-rich (Sm, R1) having a particle size of 1-20 μm 2 Fe 17 Taking alloy powder as mother alloy magnetic powder, mixing Sm diffusion source alloy powder as claimed in claim 2 with a volatile organic solvent to form a paste, uniformly mixing the mother alloy magnetic powder with the paste to obtain a mixture, wherein the mass ratio of the mother alloy magnetic powder to the diffusion source alloy powder is 88:12-97:3, and then sequentially carrying out diffusion heat treatment, hydrogen explosion treatment, dehydrogenation treatment, powder preparation and nitridation on the mixture to obtain heterogeneous single crystal magnetic powder.
4. The method of claim 3, wherein the Sm, R1 is La/Ce/Y rich 2 Fe 17 The composition of the alloy powder is expressed by atomic percent as: (Sm) 1-α R1 α ) b Fe 100-b-c M2 c Wherein R1 is at least one rare earth element other than Sm, 0.2<α<1；9<b<13; m2 is at least one of Co, Si, Ga, Al, Ni, Ti, Cu, V, Cr, Zr, Hf, Nb, Ta, Mo and W, and c is more than or equal to 0 and less than or equal to 30.
5. The method of claim 4, wherein R1 is selected from at least one of La, Ce, and Y.
6. The method of claim 4, wherein the step of preparing the master alloy magnetic powder comprises: according to (Sm) 1-α R1 α ) b Fe 100-b-c M2 c The method comprises the steps of proportioning, putting the proportioned metals Sm, pure Fe, R1 and M2 into an induction smelting furnace, smelting in high-purity Ar, using induction to heat the alloy until the raw materials are completely and uniformly melted to obtain a melt, preparing the melt into a rapid-hardening casting sheet at the water-cooling copper roller speed, placing the master alloy casting sheet into a heat treatment container, carrying out heat treatment under the protection of argon, and crushing the master alloy casting sheet into master alloy magnetic powder with the average particle of 1-20 mu M after air cooling.
7. The method for preparing inhomogeneous single crystal magnetic powder of claim 6, wherein the linear speed of the water cooled copper roller surface is 10-30m/s, the heat treatment temperature is 900-1000 deg.c, and the heat treatment time is 30-50 min.
8. The method for preparing heterogeneous single crystal magnetic powder according to claim 3, wherein the steps of performing diffusion heat treatment, hydrogen explosion treatment, dehydrogenation treatment, pulverization and nitridation on the mixture to obtain the heterogeneous single crystal magnetic powder are as follows: placing the mixture in a vacuum furnace under the protection of high-purity Ar for diffusion heat treatment, wherein the temperature of the diffusion heat treatment is 650-960 ℃, and the time of the heat treatment is 0.5-10 h; placing the casting sheet subjected to diffusion heat treatment in H at the temperature of 150 ℃ and 250 DEG C 2 Performing intermediate treatment for 1-3h, performing hydrogen explosion treatment, adjusting the furnace temperature to 550-600 ℃, and performing vacuum-pumping dehydrogenation treatment for 1.5-2.5 h; and grinding the casting sheet subjected to dehydrogenation treatment to obtain magnetic powder, and nitriding the magnetic powder for 30-40h at 400-450 ℃ by using high-purity nitrogen to obtain heterogeneous single crystal magnetic powder.
9. The method of claim 3, wherein the magnetic powder is prepared by the methodThe inhomogeneous single crystal magnetic powder is characterized by comprising a first phase, a second phase and a third phase, wherein the first phase consists of rare earth elements Sm, R1, Fe and transition metal element M2 and has Th 2 Zn 17 Or Th 2 Ni 17 The main phase of the type structure, the main phase crystal grain has a spherical or equiaxed shape and has a Sm-rich shell layer, and the thickness of the Sm-rich shell layer is between 0.1 and 1.0 mu m; the main phase constituent atoms account for 80-99% of the parent alloy atoms; the second phase is a rare earth-rich auxiliary phase, the constituent atoms of the rare earth-rich auxiliary phase account for 0.5-19% of the mother alloy, and the rare earth-rich auxiliary phase consists of (Sm, R1) (Fe, M2) 2 、(Sm，R1)(Fe，M2)T 3 、(Sm，R1)(Fe，M2)M1、(Sm，R1)M1 2 Any three of the phases, the third phase is an oxide or nitride of rare earth Sm, R1 and other unavoidable impurities.
10. Use of the inhomogeneous single crystal magnetic powder according to claim 9 for the preparation of anisotropically bonded permanent magnetic material or sintered anisotropic permanent magnetic material.
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