CN111341514A - Low-cost neodymium iron boron magnet and preparation method thereof - Google Patents
Low-cost neodymium iron boron magnet and preparation method thereof Download PDFInfo
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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
- H01F1/057—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B
- H01F1/0571—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes
- H01F1/0575—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes pressed, sintered or bonded together
- H01F1/0577—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes pressed, sintered or bonded together sintered
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- 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
- H01F41/0253—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 for manufacturing permanent magnets
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- 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
- H01F41/0253—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 for manufacturing permanent magnets
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Abstract
The invention relates to the technical field of magnetic materials, and aims to provide a low-cost neodymium iron boron magnet and a preparation method thereof, wherein the technical scheme is characterized by comprising the following components in percentage by mass: 19.5-25.5% of Nd, 5.5-6.5% of Pr, 1-2.2% of Gd, 2.5-5% of La, 2-3.8% of Co, 0.8-1.4% of B, 0.8-1.2% of Al, 0.1-0.18% of Zr, 2-2.5% of antioxidant and the balance of Fe; the preparation method comprises the following preparation steps: s1, pretreating raw materials; s2, smelting; s3, cooling the ingot; s4, hydrogen crushing to prepare powder; s5, airflow crushing; s6, magnetic field orientation molding; s7, isostatic pressing; s8, sintering; and S9, detecting. The invention has the advantages of excellent comprehensive performance of magnetic performance of the magnet and high utilization efficiency of materials, thereby obviously reducing the production cost of the sintered neodymium-iron-boron magnet.
Description
Technical Field
The invention relates to the technical field of magnetic materials, in particular to a low-cost neodymium iron boron magnet and a preparation method thereof.
Background
With the continuous expansion of the domestic rare earth permanent magnet industry, the rare earth reserve which is a precious resource in China is less and less, so that the price of main rare earth metals (such as praseodymium, neodymium, dysprosium, terbium and the like) for manufacturing the sintered neodymium iron boron is higher and higher, and the production cost of the sintered neodymium iron boron permanent magnet material is greatly increased. The application field and the application amount of the neodymium-iron-boron permanent magnet material are increased day by day, the annual market demand is increased by about 20 percent, the price of dysprosium-iron alloy and terbium is higher and higher, and the supply amount is very tight. Therefore, on the premise of maintaining the performance of the neodymium iron boron magnet, the usage amount of the main rare earth metal of the sintered neodymium iron boron is reduced as much as possible, which becomes a very important research direction.
Chinese patent application publication No. CN 102592770 a discloses a sintered NdFeB magnet and a method for manufacturing the same, the composition of which is: nd and Pr: 27.3 to 27.8 wt%, Tb: 1.0-1.8 wt%, Al: 0.1 to 0.4 wt%, Cu: 0.08 to 0.14 wt%, Co: 0-2 wt%, Ga: 0 to 0.14 wt%, B: 0.93-1.0 wt%, and the balance of Fe; and the magnet has (BH) max > 47MGOe and Hcj > 16 kOe.
The method for producing the sintered NdFeB magnet comprises the steps of: 1) and (4) preparing materials; 2) smelting in a vacuum induction rapid hardening furnace to obtain a melt-spun alloy sheet; 3) hydrogenating and crushing the melt-spun alloy sheet, and then preparing the melt-spun alloy sheet into micro powder in an air flow mill; 4) mixing the obtained micro powder; 5) pressing the mixed micro powder into a blank; 6) placing the mixture into a vacuum sintering furnace for sintering after isostatic pressing; and carrying out secondary aging after sintering to obtain the magnet.
Although the residual magnetism Br and the intrinsic coercive force Hcj are increased by adjusting the formula and the sintering process of the neodymium iron boron in the prior art scheme, the sintering temperature rise in the vacuum sintering furnace in the sintering process is one-time temperature rise sintering, so that the neodymium iron boron is heated too fast, the magnetization is not uniform, the product quality is reduced, the yield is reduced, and the production cost is greatly increased. Therefore, further improvements are needed.
SUMMARY OF THE PATENT FOR INVENTION
The invention aims to provide a low-cost neodymium iron boron magnet and a preparation method thereof, which have the advantages of excellent comprehensive performance of magnetic performance of the magnet and high utilization efficiency of materials, thereby obviously reducing the production cost of the neodymium iron boron magnet.
The above purpose of the invention is realized by the following technical scheme:
the low-cost neodymium iron boron magnet is characterized by comprising the following components in percentage by mass: 19.5-25.5% of Nd, 5.5-6.5% of Pr, 1-2.2% of Gd, 2.5-5% of La, 2-3.8% of Co, 0.8-1.4% of B, 0.8-1.2% of Al, 0.1-0.18% of Zr, 2-2.5% of antioxidant and the balance of Fe.
By adopting the technical scheme, the magnetic performance of the neodymium iron boron sintered magnet is not affected by reducing the use amount of Nd and Pr and adding La with lower cost, so that the aim of reducing the raw material cost of rare metals is fulfilled; on the other hand, because the rare earth elements are very easy to oxidize, particularly the neodymium iron boron powder has small granularity and large specific surface area and is easier to oxidize, the antioxidant is added into the components, so that the process of oxidizing the neodymium iron boron components can be slowed down, the activity of the raw material components is kept, the utilization rate of the rare earth raw materials is greatly improved on the premise of ensuring the performance of the permanent magnet, the phenomenon of reducing the yield of products caused by oxidation is reduced, and the production cost is further reduced.
Furthermore, 21.5-24.5% of Nd, 5.8-6.2% of Pr, 1.4-2.0% of Gd, 3.5-4.5% of La, 2.2-3.2% of Co, 1.0-1.2% of B, 0.9-1.1% of Al, 0.12-0.16% of Zr and 2.2-2.4% of antioxidant.
By adopting the technical scheme, the utilization rate of the raw material components can be improved as much as possible and the raw material cost can be reduced on the premise of ensuring the performance of the product by optimizing the component proportion.
Further, the antioxidant is adipic acid dihydrazide.
By adopting the technical scheme, the adipic acid dihydrazide is a bifunctional cross-linking agent, can be used as a metal deactivator, can effectively reduce the oxidation process of easily oxidized metals, and improves the oxidation resistance of rare earth metals, thereby ensuring the activity of each component and improving the yield of products.
Further, the preparation method of the low-cost neodymium iron boron magnet comprises the following steps:
s1, raw material pretreatment: removing impurities and rust on the surface of each raw material component, cutting each component into small blocks with unilateral length not more than 35mm, and blending;
s2, smelting: putting the components pretreated in the step S1 into a vacuum smelting furnace, starting heating when the vacuum degree in the furnace is pumped to 4Pa, stopping pumping and heating when the metals Nd and Pr are molten, filling argon into the vacuum smelting furnace until the pressure in the furnace reaches 0.03-0.04 MPa, and continuing heating to start smelting;
s3, cooling the ingot: after all the raw materials are melted, continuously melting for 5-10 min, pouring the alloy solution into a cold ingot mold after the surface of the alloy solution is coated with a film, and cooling and forming;
s4, hydrogen crushing into powder: adding protective gas nitrogen into a coarse crusher, and adding the alloy blocks smelted by the ingot casting in the step S2 into the coarse crusher for primary crushing; then introducing nitrogen into a hydrogen crushing furnace, adding the prepared primary crushed material into the hydrogen crushing furnace, replacing the nitrogen with hydrogen, and carrying out hydrogen crushing treatment to crush the powder material to a particle size below 40 meshes;
s5, jet milling: adding the powder prepared in the step S4 into an air-jet mill, crushing the powder into 3-4 micron powder through the air-jet mill, and cooling the powder at 0-3 ℃ at low temperature;
s6, magnetic field orientation molding: filling the powder prepared in the step S5 into a forming die, and performing orientation forming in a magnetic field press;
s7, isostatic pressing: placing the pressed blank prepared in the step S6 into a high-pressure cavity of an isostatic pressing machine, and maintaining the pressure;
s8, sintering: filling the pressed blank subjected to isostatic pressing in the step S7 into a material box, then filling the material box into a vacuum sintering furnace, vacuumizing the vacuum sintering furnace, starting heating, and cooling after sintering to obtain a neodymium iron boron product;
s9, detection: and detecting the magnetic parameters of the sintered finished products one by one, and rejecting unqualified products.
By adopting the technical scheme, smelting is carried out in a vacuum state, heating temperature and pressure are controlled, ingot casting structures with excellent quality can be obtained, α -Fe crystals can be effectively inhibited from appearing, Nd-rich phases are uniformly distributed along a grain boundary, sintering time is shortened, machinability of rare metals is improved, performance of a final product sintered neodymium iron boron magnet is improved, argon is introduced into a vacuum smelting furnace, nitrogen is introduced before a hydrogen crushing furnace is used, oxygen in equipment is discharged through inert gas, accordingly, rare metal powder is guaranteed not to be easily oxidized in an inert gas atmosphere, a hydrogen crushing powder preparation process is adopted, neodymium iron boron alloy is placed in a hydrogen environment by utilizing hydrogen absorption characteristics of rare earth intermetallic compounds, hydrogen enters the alloy along a neodymium-rich phase thin layer, the alloy is expanded and cracked, integrity of main phase grains and a neodymium-rich phase boundary phase layer is guaranteed, grain size distribution of metal powder particles is uniform and concentrated, surface defects of the particles are few, accordingly, magnetic stability of the neodymium iron boron magnet is improved, gas in blank pressing and sintering processes can discharge gas in a blank, temperature and pressure contact with the permanent magnet, and the magnet microstructure density of the magnet can be improved, and the magnet has high performance of the magnet.
Further, in the step S5, before the powder is added into the jet mill, the antioxidant adipic dihydrazide is added into the powder according to the proportion and is uniformly mixed.
By adopting the technical scheme, as the rare earth element is extremely easy to oxidize, the neodymium iron boron powder has small particle size and large specific surface area and is easy to contact and oxidize, the powder is mixed with the antioxidant before powdering, the oxidation resistance of the metal powder can be obviously improved, and the magnetic quality of a magnet product is ensured.
Further, the magnetic field intensity of the magnetic field press in the step S6 is 19000e to 20000 e.
By adopting the technical scheme, the microstructure of the magnet can be effectively improved by setting the magnetic field intensity in the magnetic field press, so that the main phase crystal boundary of the magnet is straight and regular, the anti-magnetization domain is difficult to nucleate, and the magnetic quality of the magnet is improved.
Further, in the step S7, the green compact obtained in the step S6 needs to be vacuum-packed before being loaded into the high-pressure chamber of the isostatic press.
Through adopting above-mentioned technical scheme, carry out vacuum packaging with the pressed compact before to pressed compact isostatic pressing to isolated with the oxygen atmosphere in pressed compact and the air, thereby further promote anti-oxidation.
Further, the step S8 requires that the vacuum packaging of the compact be removed before the compact is loaded into a cartridge for sintering.
Through adopting above-mentioned technical scheme, get rid of vacuum packaging before putting the pressed compact into the stove sintering, avoid vacuum packaging material to sneak into the stove sintering and mix together with the powder to lead to magnet magnetism to receive the influence, and then lead to the product quality to descend.
Further, in the step S8, the vacuum degree is 0.001 Pa-0.02 Pa, the sintering temperature is 1050 ℃ to 1105 ℃, the sintering time is 4-6 h, the sintered magnet is cooled by gas quenching, tempered at 850 ℃ to 960 ℃ for 2-3 h, continuously tempered at 420 ℃ to 660 ℃ for 1-2 h, and cooled to room temperature to obtain the neodymium-iron-boron magnet.
By adopting the technical scheme, the pressed compact is sintered and quenched by gas, and then is tempered and heat-insulated, so that the microstructure inside the pressed compact can gradually grow completely and be repaired, the main phase crystal boundary of the magnet is more straight and regular, and the coercive force of the sintered neodymium iron boron magnet is improved.
In conclusion, the invention has the following beneficial effects:
1. according to the invention, by reducing the consumption of Nd and Pr and adding La with lower cost, the magnetic property of the neodymium iron boron sintered magnet is not affected, so that the purpose of reducing the raw material cost of rare metals is achieved;
2. according to the invention, the adipic acid dihydrazide antioxidant is added into the neodymium iron boron magnet component, so that the oxidation process of the neodymium iron boron component can be slowed down, and the activity of the raw material component is maintained, thus the utilization rate of the rare earth raw material is greatly improved on the premise of ensuring the performance of the magnet, the phenomenon of reduction of the yield of the product caused by oxidation is reduced, and the production cost is further reduced;
3. according to the invention, through smelting in a vacuum state and controlling the heating temperature and pressure, an ingot casting structure with excellent quality can be obtained, α -Fe crystals can be effectively inhibited from appearing, the Nd-rich phase is uniformly distributed along the grain boundary, the sintering time is shortened, the machinability of rare metals is improved, and the performance of the final product sintered neodymium iron boron magnet is improved.
Detailed Description
The present invention will be described in further detail with reference to the following examples.
Example 1
A low-cost neodymium iron boron magnet comprises the following components in percentage by mass:
19.5% of Nd, 5.5% of Pr, 1% of Gd, 2.5% of La, 2% of Co, 0.8% of B, 0.8% of Al, 0.1% of Zr, 2% of antioxidant and the balance of Fe.
The preparation method of the low-cost neodymium iron boron magnet comprises the following steps:
s1, raw material pretreatment: removing impurities and rust on the surface of each raw material component, cutting each component into small blocks with unilateral length not more than 35mm, and blending;
s2, smelting: putting the components pretreated in the step S1 into a vacuum smelting furnace, starting heating when the vacuum degree in the furnace is pumped to 4Pa, stopping pumping and heating when the metals Nd and Pr are molten, filling argon into the vacuum smelting furnace until the pressure in the furnace reaches 0.03-0.04 MPa, and continuing heating to start smelting;
s3, cooling the ingot: after all the raw materials are melted, continuously melting for 5-10 min, pouring the alloy solution into a cold ingot mold after the surface of the alloy solution is coated with a film, and cooling and forming;
s4, hydrogen crushing into powder: adding protective gas nitrogen into a coarse crusher, and adding the alloy blocks smelted by the ingot casting in the step S2 into the coarse crusher for primary crushing; then introducing nitrogen into a hydrogen crushing furnace, adding the prepared primary crushed material into the hydrogen crushing furnace, replacing the nitrogen with hydrogen, and carrying out hydrogen crushing treatment to crush the powder material to a particle size below 40 meshes;
s5, jet milling: adding the powder prepared in the step S4 into an air-jet mill, crushing the powder into 3-4 micron powder through the air-jet mill, and cooling the powder at 0-3 ℃ at low temperature;
s6, magnetic field orientation molding: filling the powder prepared in the step S5 into a forming die, and performing orientation forming in a magnetic field press, wherein the magnetic field intensity of the magnetic field press is 19000 e-20000 e;
s7, isostatic pressing: vacuum packaging the pressed blank prepared in the step S6, filling the pressed blank into a high-pressure cavity of an isostatic pressing machine, and maintaining the pressure;
s8, sintering: removing the vacuum package of the pressed compact subjected to isostatic pressing in the step S7, filling the pressed compact into a material box, filling the material box into a vacuum sintering furnace, vacuumizing the vacuum sintering furnace, starting heating, and cooling after sintering to obtain a neodymium iron boron product; the vacuum degree is 0.001 Pa-0.02 Pa, the sintering temperature is 1050 ℃, the sintering time is 4h, the sintered magnet is cooled by gas quenching, the tempering treatment is carried out for 2h at 850 ℃, the tempering is continued for 1h at 420 ℃, and the neodymium iron boron magnet is obtained after cooling to the room temperature;
s9, detection: and detecting the magnetic parameters of the sintered finished products one by one, and rejecting unqualified products.
Example 2
A low-cost neodymium iron boron magnet comprises the following components in percentage by mass:
20.5% of Nd, 5.7% of Pr, 1.2% of Gd, 2.8% of La, 2.2% of Co, 1.0% of B, 0.9% of Al, 0.12% of Zr, 2.1% of antioxidant and the balance of Fe.
The preparation method of the low-cost neodymium iron boron magnet comprises the following steps:
s1, raw material pretreatment: removing impurities and rust on the surface of each raw material component, cutting each component into small blocks with unilateral length not more than 35mm, and blending;
s2, smelting: putting the components pretreated in the step S1 into a vacuum smelting furnace, starting heating when the vacuum degree in the furnace is pumped to 4Pa, stopping pumping and heating when the metals Nd and Pr are molten, filling argon into the vacuum smelting furnace until the pressure in the furnace reaches 0.03-0.04 MPa, and continuing heating to start smelting;
s3, cooling the ingot: after all the raw materials are melted, continuously melting for 5-10 min, pouring the alloy solution into a cold ingot mold after the surface of the alloy solution is coated with a film, and cooling and forming;
s4, hydrogen crushing into powder: adding protective gas nitrogen into a coarse crusher, and adding the alloy blocks smelted by the ingot casting in the step S2 into the coarse crusher for primary crushing; then introducing nitrogen into a hydrogen crushing furnace, adding the prepared primary crushed material into the hydrogen crushing furnace, replacing the nitrogen with hydrogen, and carrying out hydrogen crushing treatment to crush the powder material to a particle size below 40 meshes;
s5, jet milling: adding the powder prepared in the step S4 into an air-jet mill, crushing the powder into 3-4 micron powder through the air-jet mill, and cooling the powder at 0-3 ℃ at low temperature;
s6, magnetic field orientation molding: filling the powder prepared in the step S5 into a forming die, and performing orientation forming in a magnetic field press, wherein the magnetic field intensity of the magnetic field press is 19000 e-20000 e;
s7, isostatic pressing: vacuum packaging the pressed blank prepared in the step S6, filling the pressed blank into a high-pressure cavity of an isostatic pressing machine, and maintaining the pressure;
s8, sintering: removing the vacuum package of the pressed compact subjected to isostatic pressing in the step S7, filling the pressed compact into a material box, filling the material box into a vacuum sintering furnace, vacuumizing the vacuum sintering furnace, starting heating, and cooling after sintering to obtain a neodymium iron boron product; the vacuum degree is 0.001 Pa-0.02 Pa, the sintering temperature is 1060 ℃, the sintering time is 4h, the sintered magnet is cooled by gas quenching, the sintered magnet is tempered for 2h at 870 ℃, the sintered magnet is continuously tempered for 1h at 450 ℃, and the sintered magnet is cooled to room temperature to obtain the neodymium-iron-boron magnet;
s9, detection: and detecting the magnetic parameters of the sintered finished products one by one, and rejecting unqualified products.
Example 3
A low-cost neodymium iron boron magnet comprises the following components in percentage by mass:
21.5% of Nd, 5.8% of Pr, 1.4% of Gd, 3.2% of La, 2.6% of Co, 1.1% of B, 0.95% of Al, 0.14% of Zrs, 2.2% of antioxidant and the balance of Fe.
The preparation method of the low-cost neodymium iron boron magnet comprises the following steps:
s1, raw material pretreatment: removing impurities and rust on the surface of each raw material component, cutting each component into small blocks with unilateral length not more than 35mm, and blending;
s2, smelting: putting the components pretreated in the step S1 into a vacuum smelting furnace, starting heating when the vacuum degree in the furnace is pumped to 4Pa, stopping pumping and heating when the metals Nd and Pr are molten, filling argon into the vacuum smelting furnace until the pressure in the furnace reaches 0.03-0.04 MPa, and continuing heating to start smelting;
s3, cooling the ingot: after all the raw materials are melted, continuously melting for 5-10 min, pouring the alloy solution into a cold ingot mold after the surface of the alloy solution is coated with a film, and cooling and forming;
s4, hydrogen crushing into powder: adding protective gas nitrogen into a coarse crusher, and adding the alloy blocks smelted by the ingot casting in the step S2 into the coarse crusher for primary crushing; then introducing nitrogen into a hydrogen crushing furnace, adding the prepared primary crushed material into the hydrogen crushing furnace, replacing the nitrogen with hydrogen, and carrying out hydrogen crushing treatment to crush the powder material to a particle size below 40 meshes;
s5, jet milling: adding the powder prepared in the step S4 into an air-jet mill, crushing the powder into 3-4 micron powder through the air-jet mill, and cooling the powder at 0-3 ℃ at low temperature;
s6, magnetic field orientation molding: filling the powder prepared in the step S5 into a forming die, and performing orientation forming in a magnetic field press, wherein the magnetic field intensity of the magnetic field press is 19000 e-20000 e;
s7, isostatic pressing: vacuum packaging the pressed blank prepared in the step S6, filling the pressed blank into a high-pressure cavity of an isostatic pressing machine, and maintaining the pressure;
s8, sintering: removing the vacuum package of the pressed compact subjected to isostatic pressing in the step S7, filling the pressed compact into a material box, filling the material box into a vacuum sintering furnace, vacuumizing the vacuum sintering furnace, starting heating, and cooling after sintering to obtain a neodymium iron boron product; the vacuum degree is 0.001 Pa-0.02 Pa, the sintering temperature is 1070 ℃, the sintering time is 4.5h, the sintered magnet is cooled by gas quenching, the sintered magnet is tempered at 890 ℃ for 2.5h, the sintered magnet is continuously tempered at 480 ℃ for 1.5h, and the sintered magnet is cooled to room temperature to obtain the neodymium-iron-boron magnet;
s9, detection: and detecting the magnetic parameters of the sintered finished products one by one, and rejecting unqualified products.
Example 4
A low-cost neodymium iron boron magnet comprises the following components in percentage by mass:
22.5% of Nd, 6.1% of Pr, 1.6% of Gd, 3.5% of La, 3.0% of Co, 1.2% of B, 1.0% of Al, 0.15% of Zr, 2.3% of antioxidant and the balance of Fe.
The preparation method of the low-cost neodymium iron boron magnet comprises the following steps:
s1, raw material pretreatment: removing impurities and rust on the surface of each raw material component, cutting each component into small blocks with unilateral length not more than 35mm, and blending;
s2, smelting: putting the components pretreated in the step S1 into a vacuum smelting furnace, starting heating when the vacuum degree in the furnace is pumped to 4Pa, stopping pumping and heating when the metals Nd and Pr are molten, filling argon into the vacuum smelting furnace until the pressure in the furnace reaches 0.03-0.04 MPa, and continuing heating to start smelting;
s3, cooling the ingot: after all the raw materials are melted, continuously melting for 5-10 min, pouring the alloy solution into a cold ingot mold after the surface of the alloy solution is coated with a film, and cooling and forming;
s4, hydrogen crushing into powder: adding protective gas nitrogen into a coarse crusher, and adding the alloy blocks smelted by the ingot casting in the step S2 into the coarse crusher for primary crushing; then introducing nitrogen into a hydrogen crushing furnace, adding the prepared primary crushed material into the hydrogen crushing furnace, replacing the nitrogen with hydrogen, and carrying out hydrogen crushing treatment to crush the powder material to a particle size below 40 meshes;
s5, jet milling: adding the powder prepared in the step S4 into an air-jet mill, crushing the powder into 3-4 micron powder through the air-jet mill, and cooling the powder at 0-3 ℃ at low temperature;
s6, magnetic field orientation molding: filling the powder prepared in the step S5 into a forming die, and performing orientation forming in a magnetic field press, wherein the magnetic field intensity of the magnetic field press is 19000 e-20000 e;
s7, isostatic pressing: vacuum packaging the pressed blank prepared in the step S6, filling the pressed blank into a high-pressure cavity of an isostatic pressing machine, and maintaining the pressure;
s8, sintering: removing the vacuum package of the pressed compact subjected to isostatic pressing in the step S7, filling the pressed compact into a material box, filling the material box into a vacuum sintering furnace, vacuumizing the vacuum sintering furnace, starting heating, and cooling after sintering to obtain a neodymium iron boron product; the vacuum degree is 0.001 Pa-0.02 Pa, the sintering temperature is 1080 ℃, the sintering time is 4.5h, the sintered magnet is cooled by gas quenching, the sintered magnet is tempered at 910 ℃ for 2.5h, the sintered magnet is continuously tempered at 510 ℃ for 1.5h, and the sintered magnet is cooled to room temperature to obtain the neodymium-iron-boron magnet;
s9, detection: and detecting the magnetic parameters of the sintered finished products one by one, and rejecting unqualified products.
Example 5
A low-cost neodymium iron boron magnet comprises the following components in percentage by mass:
23.5% of Nd, 6.2% of Pr, 1.8% of Gd, 4.0% of La, 3.2% of Co, 1.3% of B, 1.05% of Al, 0.16% of Zrs, 2.4% of antioxidant and the balance of Fe.
The preparation method of the low-cost neodymium iron boron magnet comprises the following steps:
s1, raw material pretreatment: removing impurities and rust on the surface of each raw material component, cutting each component into small blocks with unilateral length not more than 35mm, and blending;
s2, smelting: putting the components pretreated in the step S1 into a vacuum smelting furnace, starting heating when the vacuum degree in the furnace is pumped to 4Pa, stopping pumping and heating when the metals Nd and Pr are molten, filling argon into the vacuum smelting furnace until the pressure in the furnace reaches 0.03-0.04 MPa, and continuing heating to start smelting;
s3, cooling the ingot: after all the raw materials are melted, continuously melting for 5-10 min, pouring the alloy solution into a cold ingot mold after the surface of the alloy solution is coated with a film, and cooling and forming;
s4, hydrogen crushing into powder: adding protective gas nitrogen into a coarse crusher, and adding the alloy blocks smelted by the ingot casting in the step S2 into the coarse crusher for primary crushing; then introducing nitrogen into a hydrogen crushing furnace, adding the prepared primary crushed material into the hydrogen crushing furnace, replacing the nitrogen with hydrogen, and carrying out hydrogen crushing treatment to crush the powder material to a particle size below 40 meshes;
s5, jet milling: adding the powder prepared in the step S4 into an air-jet mill, crushing the powder into 3-4 micron powder through the air-jet mill, and cooling the powder at 0-3 ℃ at low temperature;
s6, magnetic field orientation molding: filling the powder prepared in the step S5 into a forming die, and performing orientation forming in a magnetic field press, wherein the magnetic field intensity of the magnetic field press is 19000 e-20000 e;
s7, isostatic pressing: vacuum packaging the pressed blank prepared in the step S6, filling the pressed blank into a high-pressure cavity of an isostatic pressing machine, and maintaining the pressure;
s8, sintering: removing the vacuum package of the pressed compact subjected to isostatic pressing in the step S7, filling the pressed compact into a material box, filling the material box into a vacuum sintering furnace, vacuumizing the vacuum sintering furnace, starting heating, and cooling after sintering to obtain a neodymium iron boron product; the vacuum degree is 0.001 Pa-0.02 Pa, the sintering temperature is 1090 ℃, the sintering time is 5h, the sintered magnet is cooled by gas quenching, the tempering treatment is carried out for 3h at 930 ℃, the tempering is continued for 2h at 540 ℃, and the neodymium iron boron magnet is obtained after the sintered magnet is cooled to room temperature;
s9, detection: and detecting the magnetic parameters of the sintered finished products one by one, and rejecting unqualified products.
Example 6
A low-cost neodymium iron boron magnet comprises the following components in percentage by mass:
24.5% of Nd, 6.4% of Pr, 2.0% of Gd, 4.5% of La, 3.6% of Co, 1.3% of B, 1.1% of Al, 0.17% of Zr, 2.45% of antioxidant and the balance of Fe.
The preparation method of the low-cost neodymium iron boron magnet comprises the following steps:
s1, raw material pretreatment: removing impurities and rust on the surface of each raw material component, cutting each component into small blocks with unilateral length not more than 35mm, and blending;
s2, smelting: putting the components pretreated in the step S1 into a vacuum smelting furnace, starting heating when the vacuum degree in the furnace is pumped to 4Pa, stopping pumping and heating when the metals Nd and Pr are molten, filling argon into the vacuum smelting furnace until the pressure in the furnace reaches 0.03-0.04 MPa, and continuing heating to start smelting;
s3, cooling the ingot: after all the raw materials are melted, continuously melting for 5-10 min, pouring the alloy solution into a cold ingot mold after the surface of the alloy solution is coated with a film, and cooling and forming;
s4, hydrogen crushing into powder: adding protective gas nitrogen into a coarse crusher, and adding the alloy blocks smelted by the ingot casting in the step S2 into the coarse crusher for primary crushing; then introducing nitrogen into a hydrogen crushing furnace, adding the prepared primary crushed material into the hydrogen crushing furnace, replacing the nitrogen with hydrogen, and carrying out hydrogen crushing treatment to crush the powder material to a particle size below 40 meshes;
s5, jet milling: adding the powder prepared in the step S4 into an air-jet mill, crushing the powder into 3-4 micron powder through the air-jet mill, and cooling the powder at 0-3 ℃ at low temperature;
s6, magnetic field orientation molding: filling the powder prepared in the step S5 into a forming die, and performing orientation forming in a magnetic field press, wherein the magnetic field intensity of the magnetic field press is 19000 e-20000 e;
s7, isostatic pressing: vacuum packaging the pressed blank prepared in the step S6, filling the pressed blank into a high-pressure cavity of an isostatic pressing machine, and maintaining the pressure;
s8, sintering: removing the vacuum package of the pressed compact subjected to isostatic pressing in the step S7, filling the pressed compact into a material box, filling the material box into a vacuum sintering furnace, vacuumizing the vacuum sintering furnace, starting heating, and cooling after sintering to obtain a neodymium iron boron product; the vacuum degree is 0.001 Pa-0.02 Pa, the sintering temperature is 1100 ℃, the sintering time is 6h, the sintered magnet is cooled by gas quenching, the sintered magnet is tempered for 3h at 950 ℃, the sintered magnet is continuously tempered for 2h at 600 ℃, and the sintered magnet is cooled to room temperature to obtain the neodymium-iron-boron magnet;
s9, detection: and detecting the magnetic parameters of the sintered finished products one by one, and rejecting unqualified products.
Example 7
A low-cost neodymium iron boron magnet comprises the following components in percentage by mass:
25.5% of Nd, 6.5% of Pr, 2.2% of Gd, 5% of La, 3.8% of Co, 1.4% of B, 1.2% of Al, 0.18% of Zr, 2.5% of antioxidant and the balance of Fe.
The preparation method of the low-cost neodymium iron boron magnet comprises the following steps:
s1, raw material pretreatment: removing impurities and rust on the surface of each raw material component, cutting each component into small blocks with unilateral length not more than 35mm, and blending;
s2, smelting: putting the components pretreated in the step S1 into a vacuum smelting furnace, starting heating when the vacuum degree in the furnace is pumped to 4Pa, stopping pumping and heating when the metals Nd and Pr are molten, filling argon into the vacuum smelting furnace until the pressure in the furnace reaches 0.03-0.04 MPa, and continuing heating to start smelting;
s3, cooling the ingot: after all the raw materials are melted, continuously melting for 5-10 min, pouring the alloy solution into a cold ingot mold after the surface of the alloy solution is coated with a film, and cooling and forming;
s4, hydrogen crushing into powder: adding protective gas nitrogen into a coarse crusher, and adding the alloy blocks smelted by the ingot casting in the step S2 into the coarse crusher for primary crushing; then introducing nitrogen into a hydrogen crushing furnace, adding the prepared primary crushed material into the hydrogen crushing furnace, replacing the nitrogen with hydrogen, and carrying out hydrogen crushing treatment to crush the powder material to a particle size below 40 meshes;
s5, jet milling: adding the powder prepared in the step S4 into an air-jet mill, crushing the powder into 3-4 micron powder through the air-jet mill, and cooling the powder at 0-3 ℃ at low temperature;
s6, magnetic field orientation molding: filling the powder prepared in the step S5 into a forming die, and performing orientation forming in a magnetic field press, wherein the magnetic field intensity of the magnetic field press is 19000 e-20000 e;
s7, isostatic pressing: vacuum packaging the pressed blank prepared in the step S6, filling the pressed blank into a high-pressure cavity of an isostatic pressing machine, and maintaining the pressure;
s8, sintering: removing the vacuum package of the pressed compact subjected to isostatic pressing in the step S7, filling the pressed compact into a material box, filling the material box into a vacuum sintering furnace, vacuumizing the vacuum sintering furnace, starting heating, and cooling after sintering to obtain a neodymium iron boron product; the vacuum degree is 0.001 Pa-0.02 Pa, the sintering temperature is 1105 ℃, the sintering time is 6h, the sintered magnet is cooled by gas quenching, the tempering treatment is carried out for 3h at 960 ℃, the tempering is continued for 2h at 660 ℃, and the neodymium iron boron magnet is obtained after cooling to the room temperature;
s9, detection: and detecting the magnetic parameters of the sintered finished products one by one, and rejecting unqualified products.
Performance detection
Neodymium iron boron magnets with the same specification are prepared by sintering according to the method in the embodiments 1 to 7, and the magnetic performance of each yarn sample is continuously tested, and the test results are shown in table 1:
TABLE 1 magnetic performance test results of sintered Nd-Fe-B magnets of each example
As can be seen from Table 1, the magnetic performance test results in the embodiments 1-7 are in a better level, and the good comprehensive magnetic performance of the NdFeB magnet is ensured on the premise of controlling the production cost of the NdFeB magnet.
The present embodiment is only for explaining the patent of the present invention, and it is not limited to the patent of the present invention, and those skilled in the art can make modifications of the present embodiment without inventive contribution as required after reading the present specification, but all are protected by the patent law within the scope of the claims of the present patent.
Claims (9)
1. The low-cost neodymium iron boron magnet is characterized by comprising the following components in percentage by mass: 19.5-25.5% of Nd, 5.5-6.5% of Pr, 1-2.2% of Gd, 2.5-5% of La, 2-3.8% of Co, 0.8-1.4% of B, 0.8-1.2% of Al, 0.1-0.18% of Zr, 2-2.5% of antioxidant and the balance of Fe.
2. A low cost ndfeb magnet according to claim 1, wherein: 21.5-24.5% of Nd, 5.8-6.2% of Pr, 1.4-2.0% of Gd, 3.5-4.5% of La, 2.2-3.2% of Co, 1.0-1.2% of B, 0.9-1.1% of Al, 0.12-0.16% of Zr and 2.2-2.4% of antioxidant.
3. A low cost NdFeB magnet according to any of claims 1-2, wherein: the antioxidant is adipic acid dihydrazide.
4. The method for preparing the low-cost neodymium-iron-boron magnet according to any one of claims 1 to 3, characterized by comprising the following steps:
s1, raw material pretreatment: removing impurities and rust on the surface of each raw material component, cutting each component into small blocks with unilateral length not more than 35mm, and blending;
s2, smelting: putting the components pretreated in the step S1 into a vacuum smelting furnace, starting heating when the vacuum degree in the furnace is pumped to 4Pa, stopping pumping and heating when the metals Nd and Pr are molten, filling argon into the vacuum smelting furnace until the pressure in the furnace reaches 0.03-0.04 MPa, and continuing heating to start smelting;
s3, cooling the ingot: after all the raw materials are melted, continuously melting for 5-10 min, pouring the alloy solution into a cold ingot mold after the surface of the alloy solution is coated with a film, and cooling and forming;
s4, hydrogen crushing into powder: adding protective gas nitrogen into a coarse crusher, and adding the alloy blocks smelted by the ingot casting in the step S2 into the coarse crusher for primary crushing; then introducing nitrogen into a hydrogen crushing furnace, adding the prepared primary crushed material into the hydrogen crushing furnace, replacing the nitrogen with hydrogen, and carrying out hydrogen crushing treatment to crush the powder material to a particle size below 40 meshes;
s5, jet milling: adding the powder prepared in the step S4 into an air-jet mill, crushing the powder into 3-4 micron powder through the air-jet mill, and cooling the powder at 0-3 ℃ at low temperature;
s6, magnetic field orientation molding: filling the powder prepared in the step S5 into a forming die, and performing orientation forming in a magnetic field press;
s7, isostatic pressing: placing the pressed blank prepared in the step S6 into a high-pressure cavity of an isostatic pressing machine, and maintaining the pressure;
s8, sintering: filling the pressed blank subjected to isostatic pressing in the step S7 into a material box, then filling the material box into a vacuum sintering furnace, vacuumizing the vacuum sintering furnace, starting heating, and cooling after sintering to obtain a neodymium iron boron product;
s9, detection: and detecting the magnetic parameters of the sintered finished products one by one, and rejecting unqualified products.
5. The method for preparing a low-cost neodymium-iron-boron magnet according to claim 4, characterized in that: in the step S5, before the powder is added into the jet mill, the antioxidant adipic dihydrazide is added into the powder according to the proportion and is uniformly mixed.
6. The method for preparing a low-cost neodymium-iron-boron magnet according to claim 4, characterized in that: the magnetic field intensity of the magnetic field press in the step S6 is 19000e to 20000 e.
7. The method for preparing a low-cost neodymium-iron-boron magnet according to claim 4, characterized in that: in the step S7, the green compact prepared in the step S6 needs to be vacuum-packed before being loaded into a high-pressure cavity of an isostatic press.
8. The method for preparing a low-cost neodymium-iron-boron magnet according to claim 4, characterized in that: the step S8 requires vacuum packing of the compact to be removed before the compact is loaded into a capsule for sintering.
9. The method for preparing a low-cost neodymium-iron-boron magnet according to claim 4, characterized in that in the step S8, the vacuum degree is 0.001 Pa-0.02 Pa, the sintering temperature is 1050 ℃ -1105 ℃, the sintering time is 4-6 h, the sintered magnet is cooled by gas quenching, the magnet is tempered at 850 ℃ -960 ℃ for 2-3 h, the magnet is continuously tempered at 420 ℃ -660 ℃ for 1-2 h, and the magnet is cooled to room temperature to obtain the neodymium-iron-boron magnet.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112447390A (en) * | 2020-12-02 | 2021-03-05 | 江苏巨鑫磁业有限公司 | Preparation process of neodymium iron boron NdFeB superfine permanent magnet powder |
| CN112712987A (en) * | 2020-12-09 | 2021-04-27 | 宁波韵升股份有限公司 | Preparation method of Halbach magnet |
| CN115376810A (en) * | 2022-09-01 | 2022-11-22 | 沭阳康顺磁性器材有限公司 | Magnetic material with high magnetic stability and production process thereof |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04119604A (en) * | 1990-09-11 | 1992-04-21 | Fuji Denki Kk | Manufacture of bonded magnet |
| CN102592778A (en) * | 2012-03-15 | 2012-07-18 | 宁德市星宇科技有限公司 | Low-cost sintered NdFeB (neodymium-ferrum-boron) magnet and manufacture method thereof |
| CN110473682A (en) * | 2019-07-19 | 2019-11-19 | 宁波可可磁业股份有限公司 | A kind of neodymium iron boron magnetic body and its preparation process |
-
2020
- 2020-03-25 CN CN202010220416.XA patent/CN111341514A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04119604A (en) * | 1990-09-11 | 1992-04-21 | Fuji Denki Kk | Manufacture of bonded magnet |
| CN102592778A (en) * | 2012-03-15 | 2012-07-18 | 宁德市星宇科技有限公司 | Low-cost sintered NdFeB (neodymium-ferrum-boron) magnet and manufacture method thereof |
| CN110473682A (en) * | 2019-07-19 | 2019-11-19 | 宁波可可磁业股份有限公司 | A kind of neodymium iron boron magnetic body and its preparation process |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112447390A (en) * | 2020-12-02 | 2021-03-05 | 江苏巨鑫磁业有限公司 | Preparation process of neodymium iron boron NdFeB superfine permanent magnet powder |
| CN112712987A (en) * | 2020-12-09 | 2021-04-27 | 宁波韵升股份有限公司 | Preparation method of Halbach magnet |
| CN115376810A (en) * | 2022-09-01 | 2022-11-22 | 沭阳康顺磁性器材有限公司 | Magnetic material with high magnetic stability and production process thereof |
| CN115376810B (en) * | 2022-09-01 | 2023-11-14 | 沭阳康顺磁性器材有限公司 | Magnetic material with high magnetic stability and production process thereof |
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