CN116741484A - Samarium-iron alloy, samarium-iron-nitrogen permanent magnet material, and preparation methods and applications thereof - Google Patents

Samarium-iron alloy, samarium-iron-nitrogen permanent magnet material, and preparation methods and applications thereof Download PDF

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CN116741484A
CN116741484A CN202210232108.8A CN202210232108A CN116741484A CN 116741484 A CN116741484 A CN 116741484A CN 202210232108 A CN202210232108 A CN 202210232108A CN 116741484 A CN116741484 A CN 116741484A
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samarium
iron
hours
reaction
iron alloy
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吴茂林
师大伟
侯龙泉
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Fujian Changting Jinlong Rare Earth Co Ltd
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Fujian Changting Jinlong Rare Earth Co Ltd
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    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01FMAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/032Magnets 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
    • H01F1/04Magnets 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
    • H01F1/047Alloys characterised by their composition
    • H01F1/053Alloys characterised by their composition containing rare earth metals
    • H01F1/055Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5
    • H01F1/0553Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 obtained by reduction or by hydrogen decrepitation or embrittlement
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01FMAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/032Magnets 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
    • H01F1/04Magnets 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
    • H01F1/047Alloys characterised by their composition
    • H01F1/053Alloys characterised by their composition containing rare earth metals
    • H01F1/055Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5
    • H01F1/059Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and Va elements, e.g. Sm2Fe17N2
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01FMAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F41/00Apparatus 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
    • H01F41/02Apparatus 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
    • H01F41/0253Apparatus 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
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01FMAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F41/00Apparatus 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
    • H01F41/02Apparatus 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
    • H01F41/0253Apparatus 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
    • H01F41/0293Apparatus 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 diffusion of rare earth elements, e.g. Tb, Dy or Ho, into permanent magnets

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Manufacture Of Metal Powder And Suspensions Thereof (AREA)

Abstract

The application discloses a samarium-iron alloy, a samarium-iron-nitrogen permanent magnet material, and a preparation method and application thereof. The preparation method of the samarium-iron alloy comprises the following steps: sm is to 2 O 3 Fe and Ca are subjected to reduction diffusion reaction and crushing treatment; wherein Sm is 2 O 3 The average particle size D50 of (2) is 0.5-4 mu m; the average particle size D50 of Fe is 50-150 mu m; the porosity of Fe is 10-40%. In the preparation method, large-granularity iron powder is adopted, the cost is low, and the prepared samarium-iron-nitrogen permanent magnet material has low impurity content and excellent magnetic property.

Description

Samarium-iron alloy, samarium-iron-nitrogen permanent magnet material, and preparation methods and applications thereof
Technical Field
The application relates to a samarium-iron alloy, a samarium-iron-nitrogen permanent magnet material, and a preparation method and application thereof.
Background
The Fe-N based rare earth permanent magnetic material has temperature stability comparable to that of samarium-cobalt, and the main components consisting of samarium and iron determine that the manufacturing cost is low, and the price fluctuation of raw materials is extremely small, so that the Fe-N based rare earth permanent magnetic material becomes a materialIdeal choice of cost-stable controllable permanent magnets in downstream applications. The Fe-N based rare earth permanent magnet material has excellent theoretical magnetic performance, and based on the interstitial effect of nitrogen in the rare earth-transition metal compound, the Curie temperature is 100 ℃ higher than that of the neodymium-iron-boron material, and the Fe-N based rare earth permanent magnet material has been developed into an important research hot spot in the rare earth permanent magnet field in recent years. Due to Sm 2 Fe 17 N 3 The magnetic powder can show high coercive force when the grain size is not larger than that of single domain particles, and in order to economically and efficiently obtain fine grain structures, a melt rapid quenching method, a hydrogenation disproportionation method, a mechanical alloying method (CN 1202537C), a rapid solidification casting method (CN 106312077B) or a reduction diffusion method (CN 1424165A) is generally adopted in the industry, wherein the reduction diffusion method is focused by researchers due to the advantages of simple equipment, low raw material cost, easy implementation of process conditions and the like.
In the process of preparing samarium-iron-nitrogen magnetic powder by a reduction diffusion method, in order to enable the diffusion reaction to be more complete and simultaneously obtain a product with small particle size, a reduction diffusion process is often promoted by adopting a mode of reducing the particle size of raw material iron powder. Due to the uniformity of raw material mixing, partial iron powder remains which are difficult to avoid in the reduction diffusion process, and the small soft magnetic powder remains in the product and is difficult to effectively separate, so that the overall performance of the magnetic powder is reduced. Meanwhile, the performance of the alloy powder is reduced due to the fact that the smaller iron powder is easy to oxidize, and the price of the smaller iron powder, particularly the nanoscale iron powder, is several times that of common iron powder, so that the manufacturing cost is increased due to the fact that the smaller iron powder raw materials are used.
Therefore, there is a need to provide a preparation method of a high-efficiency and low-cost samarium-iron alloy and samarium-iron-nitrogen permanent magnet material, and the prepared samarium-iron-nitrogen permanent magnet material has low impurity content and excellent magnetic property.
Disclosure of Invention
The application provides a samarium-iron alloy, a samarium-iron-nitrogen permanent magnet material, a preparation method and application thereof, and aims to overcome the defects that in the preparation method of the samarium-iron-nitrogen permanent magnet in the prior art, fine iron powder is expensive and easy to oxidize, and meanwhile, the residual fine iron powder is difficult to separate, so that the magnetic performance is deteriorated. In the preparation method, large-granularity iron powder is adopted, the cost is low, and the prepared samarium-iron-nitrogen permanent magnet material has low impurity content and excellent magnetic property.
In order to achieve the above object, the present application provides the following technical solutions:
one of the technical schemes provided by the application is as follows: a preparation method of samarium-iron alloy comprises the following steps: sm is to 2 O 3 Fe and Ca are subjected to reduction diffusion reaction and crushing treatment;
wherein said Sm 2 O 3 The average particle size D50 of (2) is 0.5-4 mu m;
the average particle size D50 of Fe is 50-150 mu m; the porosity of Fe is 10% -40%.
In the application, the Sm 2 O 3 Sm can be conventional in the art 2 O 3 And (3) powder. The Sm is 2 O 3 The average particle size D50 of (2) is preferably 1 to 2. Mu.m.
The average particle size D50 of Fe is preferably 80 to 120. Mu.m.
The porosity of Fe is preferably 25 to 40%. Porosity refers to the percentage of the pore volume in a bulk material to the total volume of the material in its natural state (generally referred to as the state without the action of external forces).
The Fe generally refers to an iron powder having a porous structure, preferably a porous iron powder or a foam iron powder. The commercial sources of the porous iron powder and the foam iron powder may be conventional in the art, such as Shijia micro-technology Co.
The Ca may be conventional in the art, such as metallic calcium, which is commercially available conventionally in the art. The physical morphology of the metallic calcium may be conventional in the art, such as metallic calcium particles. The particle size of the metallic calcium particles may be conventional in the art, for example 1-2 mm.
In the application, the Sm 2 O 3 The Fe and Ca may be as in Sm 2 O 3 +17Fe+3Ca=Sm 2 Fe 17 The reaction equation for +3CaO determines the material ratios.
Wherein, in order to ensure the sufficient reduction of the samarium oxide, the metal Ca is generally prepared according to 1.05 to 1.5 times of the theoretical amount determined by an equation (5 to 50 percent of excess),at the same time, considering the volatilization of metal Sm in the process of reduction diffusion reaction at high temperature, sm 2 O 3 The dosing is generally carried out in 1.05-1.3 times the theoretical amount determined by the above equation (5% -30% excess).
Preferably, the Sm 2 O 3 And the molar ratio of Fe is 1: (13-17), for example 1:16.2.
preferably, the Sm 2 O 3 And the molar ratio of Ca is 1: (2 to 5), for example, 1:2.4,1:3 or 1:4.3.
in the present application, the reduction diffusion reaction may be conventional in the art, and may generally include a reduction process and a diffusion process; the reduction process and the diffusion process can be independently Sm 2 O 3 And (3) placing Fe and Ca in a vacuum heat treatment furnace, and maintaining the temperature at the reaction temperature for a period of time after the temperature is increased from the room temperature to the reaction temperature.
In the present application, in the reduction diffusion reaction, the reaction temperature and the reaction time of the reduction process and the diffusion process may be the same or different.
For example, when the reaction temperatures of the reduction process and the diffusion process are the same, the reaction temperatures of the reduction process and the diffusion process are independently 1050 to 1180 ℃, such as 1120 ℃ or 1140 ℃; the reaction time of the reduction process and the diffusion process is independently 2 to 13 hours, for example 5 hours, 6 hours, 8 hours, 9 hours or 10 hours.
For another example, when the reaction temperatures of the reduction process and the diffusion process are different, the reaction temperature of the reduction process is 850 to 950 ℃, preferably 900 ℃, and the reaction time of the reduction process is 1 to 5 hours, for example 2 hours or 3 hours; the reaction temperature of the diffusion process is 1050-1180 ℃, such as 1100 ℃, 1120 ℃, 1140 ℃, 1150 ℃ or 1160 ℃, and the reaction time of the diffusion process is 2-10 hours, such as 4 hours, 6 hours or 8 hours.
In the present application, the reduction diffusion reaction is more preferably carried out according to the following steps:
wherein the reduction process is to keep the mixture A for 1 to 5 hours at the temperature of 850 to 950 ℃ to lead Sm to be 2 O 3 Fully reducing to obtain a mixed material B; the mixed material A is Sm 2 O 3 Fe and Ca;
the diffusion process is to keep the mixed material B for 2-10 hours at 1050-1180 ℃ so as to diffuse the metal Sm into Fe powder and form samarium-iron alloy.
In the present application, the samarium iron alloy is generally Sm 2 Fe 17 And (3) alloy.
In the present application, the reduction and diffusion reaction is more preferably carried out under the protection of an inert gas.
Wherein the inert gas may be an inert gas conventional in the art, such as argon. Generally, the vacuum degree in the vacuum furnace is kept below 0.1Pa before the mixture A is raised from room temperature to the reaction temperature in the reduction process, and high-purity argon is filled into the vacuum heat treatment furnace after the mixture A reaches the reaction temperature in the reduction process.
In the present application, the crushing treatment may include coarse crushing, jet milling, and hydrogen crushing.
Wherein after the reduction diffusion reaction is completed, the product is Sm 2 Fe 17 And the components such as CaO and Ca are mixed and adhered and are in a caking state, and the coarse crushing can reduce the size and improve the efficiency of the subsequent hydrogen crushing.
The rough crushing can be conventional in the art, and is generally performed by mechanically crushing the samarium iron alloy obtained after the reduction diffusion reaction, for example, jaw crushing or disc grinding crushing. After the coarse crushing, the samarium-iron alloy generally has an average particle diameter D50 of <2mm.
Wherein, the jet milling can be conventional in the art, and generally, jet milling is adopted to crush and sort the rough crushed samarium-iron alloy, so that the agglomerated product after the reaction is crushed and dispersed.
After the jet milling, the average particle diameter D50 of the samarium-iron alloy can be 0.5-25 mu m.
The jet milling can separate the large particle iron powder (> 25 μm) which is not fully reacted from the product to obtain a mixed product without iron powder.
Wherein the hydrogen disruption may be in the artDomain convention, generally refers to the use of H 2 Crushing.
The hydrogen disruption may be performed in a vacuum hydrogen disruption furnace.
The hydrogen crushing can be carried out at 500-900 mbar H 2 In a gaseous atmosphere.
The hydrogen disruption may be performed according to the following process: the samarium iron alloy after jet milling is subjected to hydrogen absorption for 2 to 5 hours at the temperature of between 150 and 250 ℃ and is subjected to vacuum pumping for dehydrogenation at the temperature of between 250 and 350 ℃.
The hydrogen disruption can lead Sm in the mixed product 2 Fe 17 The alloy is broken by hydrogen absorption and the residual metal Ca layer attached on the surface of the product is converted into CaH 2 Pulverizing and peeling.
The second technical scheme provided by the application is as follows: a samarium iron alloy prepared by the preparation method described above.
In the present application, the samarium iron alloy is preferably in a powder form.
In the present application, the samarium iron alloy preferably has an average particle diameter D50 of 0.2 to 4. Mu.m, for example, 1.7. Mu.m, 1.8. Mu.m, 2.1. Mu.m, 2.3. Mu.m, or 2.5. Mu.m.
The third technical scheme provided by the application is as follows: an application of the samarium-iron alloy in preparing samarium-iron-nitrogen permanent magnet materials.
The technical scheme provided by the application is as follows: a preparation method of a samarium-iron-nitrogen permanent magnet material comprises the following steps: the samarium-iron alloy is subjected to nitriding treatment.
In the present application, the nitriding process may be a conventional nitriding process in the art.
Wherein the temperature of the nitriding treatment may be conventional in the art, e.g. 450-550 ℃, e.g. 480 ℃, 500 ℃ or 520 ℃.
The pressure of the nitriding treatment may be conventional in the art, for example, 0.09MPa to 1.5MPa, for example, 0.2MPa, 0.5MPa, 0.8MPa, 0.9MPa, 1MPa, 1.2MPa, or 1.5MPa.
The nitriding treatment time may be conventional in the art, preferably 4 to 20 hours, for example 5 hours, 6 hours, 10 hours, 12 hours or 15 hours. And nitriding for 5-20 hours under the condition of 0.09-1.5 MPa.
The nitriding medium may be conventional in the art, e.g., N 2 Or NH 3 For example, N 2 +H 2 Mixed gas of (2), N 2 +NH 3 Mixed gas of (2) NH 3 +H 2 Or N 2 +NH 3 +H 2 Is a mixed gas of (a) and (b).
In the application, sm in the nitriding process 2 Fe 17 Alloy nitriding to form Sm 2 Fe 17 N 3 A compound.
In the present application, after the nitriding treatment, a step of washing with water and drying is generally included.
Wherein the water washing process may be conventional in the art for removing CaO, ca, caH from the mixed product 2 And the like.
The aqueous wash solution used for the aqueous wash may be conventional in the art, such as water. Preferably, a small amount of weak acid can be added into the water washing solution, and the pH value of the water washing solution is kept to be more than or equal to 6. The weak acid may be a weak acid conventional in the art, such as acetic acid.
The washing may further comprise a step of dehydration treatment. The solvent for the dehydration treatment may be conventional in the art, such as an organic solvent. The organic solvent may be alcohol or acetone.
Wherein the drying process may be conventional in the art, such as vacuum drying.
In the present application, preferably, after the drying, the steps of air flow dispersion and classification are further included. And crushing and dispersing the dried and agglomerated product to obtain the samarium-iron-nitrogen permanent magnet material with proper particle size.
Wherein, the air flow dispersing and classifying process can adopt an air flow mill.
The gas used in the jet mill may be an inert gas as is conventional in the art. The inert gas may be helium, nitrogen or argon.
Preferably, the product is subjected to both antioxidant and dispersing treatments during the gas flow dispersing and classifying process.
The antioxidant treatment may be performed by adding an organic antioxidant during the air-jet milling process. The amount of the organic antioxidant added is preferably 0.2 to 2.5%, for example 0.5%.
The dispersion treatment may be performed by adding a dispersing agent during the air-jet milling. The amount of the dispersant added is preferably 0.2 to 2.5%, for example, 0.5%.
Preferably, the sum of the addition amounts of the organic antioxidant and the dispersant is 0.8 to 4.0%, for example 1% or 1.5%.
The technical scheme provided by the application is as follows: a samarium-iron-nitrogen permanent magnet material is prepared by the preparation method of the samarium-iron-nitrogen permanent magnet material.
In the present application, the samarium iron nitrogen permanent magnet material may have an average particle diameter D50 of 0.2 to 4 μm, for example, 1.7 μm, 1.8 μm, 2.1 μm, 2.3 μm or 2.5 μm.
The technical scheme provided by the application is as follows: use of a samarium iron nitrogen permanent magnet material as hereinbefore described as an electromagnetic element.
On the basis of conforming to the common knowledge in the field, the above preferred conditions can be arbitrarily combined to obtain the preferred examples of the application.
The reagents and materials used in the present application are commercially available.
The application has the positive progress effects that:
(1) The application adopts large-granularity porous iron powder which is matched with fine-granularity samarium oxide powder, and in the reduction process, the material accumulation state of the porous iron powder wrapped by the samarium oxide powder is formed after full mixing, and in the diffusion process, the metal samarium is fully diffused into the iron powder through the gaps of the porous iron powder to form Sm 2 Fe 17 Alloy and spontaneously break up the porous iron powder undergoing diffusion reaction into small particles Sm 2 Fe 17 Alloy, but unreacted iron powder maintains the original large particle form, and provides possibility for removing redundant iron powder by subsequent airflow separation.
(2) The application can further crush and sort the rough crushed product after reduction and diffusion by using an inert gas jet mill, so that the residual large-particle iron powder which does not undergo reduction and diffusion reaction in the product is separated from the product, the product with little iron-containing impurity is obtained, the alpha-Fe soft magnetic phase of the final magnet is avoided, and the high coercive force of the magnetic powder is ensured.
(3) The application can carry out hydrogen crushing treatment on the reduction diffusion product after the first air flow mill separation, so that larger particles Sm with the granularity of 4-25 mu m in the product 2 Fe 17 The product is further crushed into 0.2-4 mu m of fine Sm by absorbing hydrogen 2 Fe 17 Alloy powder. The fine alloy powder is advantageous for improving the subsequent nitriding efficiency and nitriding degree, and has high coercivity.
(4) The application can lead Sm in the mixed product to be prepared by nitriding the reduced diffusion product 2 Fe 17 Nitriding to form Sm 2 Fe 17 N 3 Compound, then washing the product to remove impurities, avoiding Sm caused in the traditional mode of washing and nitriding 2 Fe 17 Sm formed after alloy water washing corrosion, oxidation and nitridation 2 Fe 17 N 3 The compound has high normal temperature stability, is not easy to oxidize and corrode, is convenient for fully washing the mixed product to remove impurities, and has low Ca and O contents and high magnetic property.
Drawings
FIG. 1 is an SEM image of a fine-grained samarium oxide feedstock of example 1.
Fig. 2 is an SEM image of the porous iron powder raw material in example 1.
Fig. 3 is an SEM image of the infiltration package of the metal samarium formed after the reduction of the large-particle porous iron powder with the fine-particle size samarium oxide in example 1.
Fig. 4 is an SEM image of the mixed product after reduction diffusion in example 1.
FIG. 5 is a particle size distribution diagram of the mixed product after reduction and diffusion in example 1.
FIG. 6 is a particle size distribution diagram of the reduced diffusion mixture after air stream disruption and separation to remove iron in example 1.
Detailed Description
The application is further illustrated by means of the following examples, which are not intended to limit the scope of the application. The experimental methods, in which specific conditions are not noted in the following examples, were selected according to conventional methods and conditions, or according to the commercial specifications.
In the following examples and comparative examples, porous iron powder was purchased from Shijia micro-tech Co., ltd; spherical iron powder means iron powder in the shape of dense spherical (its density is 7.8g/cm 3 ) Purchased from Zhongzhixin shield company.
Example 1
The preparation process of the samarium-iron-nitrogen magnetic powder in the embodiment 1 comprises the following steps: batching, reduction diffusion, coarse product crushing, product airflow separation, hydrogen crushing, nitriding, impurity washing, product drying, airflow dispersion and classification, and obtaining the magnetic powder.
The method comprises the following specific steps:
(1) As a raw material for the reduction diffusion reaction, porous iron powder having a particle size of 50 μm (D50) was used, and the porosity of the porous iron powder was 10%. The porous iron powder has high porosity and high reaction activity, and can make the reaction fully and quickly carried out, and the reaction or the reaction is easy to break. Porosity refers to the percentage of the pore volume in a bulk material to the total volume of the material in its natural state (generally referred to as the state without the action of external forces).
(2) Samarium oxide powder, the particle size of which was 0.5 μm (D50), was used as a raw material.
(3) The ingredients were dosed according to the molar ratios of the components in table 1: specifically, the material proportion is according to Sm 2 O 3 +17Fe+3Ca=Sm 2 Fe 17 Reaction equation for +3CaO to ensure sufficient reduction of samarium oxide, metal Ca was dosed 1.1 times the theoretical amount (10% excess) as determined by the equation, while considering volatilization of metal Sm during the reduction diffusion reaction at high temperature, sm 2 O 3 The ingredients (5% excess) were dosed 1.05 times the theoretical amount determined by the above equation, after which the raw materials were placed in a mixer for thorough mixing.
TABLE 1
(4) Reduction diffusion:
the reduction process comprises the following steps: the fully mixed raw materials are placed in a vacuum heat treatment furnace to heat up, and the vacuum degree in the vacuum furnace is kept in the process of raising the temperature from the room temperature to the reduction treatment temperature<0.1Pa. After the material is heated to the reduction temperature, high-purity argon is filled into the furnace body, the argon pressure is 600mbar, the material is subjected to reduction treatment after being kept at 950 ℃ for 2 hours, so that the metal calcium is melted and Sm is obtained 2 O 3 Reducing to samarium metal.
Diffusion process: after the reduction treatment, the materials are continuously heated to 1155 ℃ and kept for 6 hours for diffusion treatment, the argon pressure of the diffusion treatment atmosphere is 900mbar, so that the metal Sm diffuses into the porous iron powder to form Sm 2 Fe 17 The alloy spontaneously breaks into alloy powder of 2-25 mu m.
(5) Coarse crushing: and (3) carrying out mechanical coarse crushing on the product after reduction and diffusion to ensure that the granularity of the product is less than 2mm, wherein the coarse crushing can be carried out by jaw crushing, disc grinding crushing and the like.
(6) Jet milling: the coarse crushed powder is further crushed and separated by an air flow mill, the agglomerated product after the reaction is crushed and dispersed, the mixed product with the granularity of 0.5-25 mu m is obtained by separation, and the large particle iron powder (25 mu m) which is not completely reacted is separated from the product, so that the mixed product without the iron powder is obtained.
(7) Hydrogen crushing: placing the powder after air flow grinding into a vacuum hydrogen breaking furnace for hydrogen breaking, vacuumizing the furnace body, and charging 800mbar H 2 The temperature of the gas is raised to 150 ℃ to absorb hydrogen for 2 hours, and the gas is vacuumized at 300 ℃ (vacuum degree<0.1 Pa) to dehydrogenate Sm in the mixed product 2 Fe 17 The alloy is broken by hydrogen absorption and the residual metal Ca layer attached on the surface of the product is converted into CaH 2 Pulverizing and peeling.
(8) Nitriding: nitriding the crushed product at 450 deg.c and 1.5MPa to N medium 2 Nitriding for 20h to ensure Sm in the mixed product 2 Fe 17 Alloy nitriding to form Sm 2 Fe 17 N 3 A compound.
(9) Washing: washing the nitrided product with water to remove CaO, ca, caH in the mixed product 2 And adding a small amount of weak acid such as acetic acid in the water washing process to keep the pH value of the water washing solution to be more than or equal to 6, and dehydrating the water washed product by using alcohol after water washing.
(10) And (5) carrying out vacuum drying on the fully washed and dehydrated product.
(11) The powder after vacuum drying is subjected to nitrogen or argon jet mill to crush and disperse the dried and agglomerated product, and Sm with the particle diameter (D50) of about 2.5 μm is obtained 2 Fe 17 N 3 Organic antioxidant and dispersant can be added in the grinding process of the magnetic powder to perform antioxidation and dispersion treatment on the magnetic powder, and the addition amount of the additive is 1.0%.
Examples 2 to 4 and comparative examples 1 to 5
Example 1 was repeated except that the process conditions were as set forth in tables 1 and 2.
TABLE 2
Effect examples
1. SEM observation of material, particle size distribution
Fig. 1, fig. 2, fig. 3 and fig. 4 are SEM images of the mixed product of the fine-grained samarium oxide raw material, the porous iron powder raw material, the large-grained porous iron powder, and the metal samarium infiltration-coated state formed after the reduction of the fine-grained samarium oxide in example 1, respectively.
As can be seen from FIGS. 1 to 4, the large-granularity porous iron powder is matched with the fine-granularity samarium oxide raw material, and the material accumulation state of the samarium oxide powder coated porous iron powder is formed after full mixing in the reduction diffusion process,the reduced samarium fully wraps the iron powder particles in the reduction diffusion process, and rapidly and fully diffuses into the iron powder through the gaps of the porous iron powder to form Sm 2 Fe 17 The alloy is spontaneously crushed into samarium-iron alloy powder, but the incompletely reacted iron powder particles cannot be sufficiently spontaneously crushed, and finally exist in the form of large particles in the mixed product.
FIG. 5 is a particle size distribution diagram of the mixture product after reduction and diffusion in example 1, and FIG. 6 is a particle size distribution diagram of the mixture after reduction and diffusion by gas stream disruption and separation and iron removal in example 1. As can be seen from the figure, after crushing and sorting by air flow, the unreacted and completely large-particle residual iron powder in the mixed product is completely removed.
2. The samarium-iron-nitrogen permanent magnet materials prepared in the above examples and comparative examples were subjected to component measurement, and the results show that Sm 2 Fe 17 In the alloy material, except for unavoidable samarium volatilization (designed as 5%) and different impurity content in the reduction diffusion process, the rest components are similar to Sm 2 Fe 17 In the subsequent jet milling, hydrogen crushing and nitriding processes, the contents of other components except Fe impurity and oxygen impurity are unchanged, and Ca, caO and other components in the mixed product are removed after water washing to obtain purer Sm 2 Fe 17 N 3 Powder (Sm in examples 1 to 5) 2 Fe 17 N 3 Purity of the powder>98%)。
3. Performance tests were performed on the samarium-iron-nitrogen permanent magnet materials prepared in the above examples and comparative examples, and the test results are shown in table 3 below:
the magnetic properties were measured using a Vibrating Sample Magnetometer (VSM), device model LakeShore 7411.
The granularity test is carried out by adopting a laser granularity meter, and the equipment model is Malvern Mastersizer2000.
The component detection was performed using an X-ray fluorescence spectrometer, and the apparatus model was Panalytical Axios max.
The oxygen content was measured using an oxygen nitrogen analyzer, equipment model number Horiba EMGA-620W.
The alpha-Fe detection was performed using an X-ray diffractometer, device model Bruker D8DISCOVER.
TABLE 3 Table 3
From the above test results, it can be seen that:
examples 1 to 5: the Sm obtained 2 Fe 17 N 3 The magnetic powder has excellent performance, wherein Br is more than or equal to 13.5kGs, hcj is more than or equal to 14.8kOe, and BHmax is more than or equal to 38MGOe; the content of alpha-Fe is less than or equal to 0.56wt%, the oxygen content is less than or equal to 0.78wt% and the content of residual Ca is less than or equal to 0.03wt%; it can be seen that the porous iron powder has an average particle size D50 of 50 to 150 mu m and a porosity of 10 to 40%, and Sm has an average particle size D50 of 0.5 to 4 mu m 2 O 3 Can effectively reduce Sm 2 Fe 17 N 3 The impurity content in the magnetic powder and improves the magnetic performance;
meanwhile, the molar ratio of the porous iron powder at the time of the compounding was slightly higher in example 5 as compared with example 4, but since both the average particle size D50 and the porosity of the porous iron powder are within the scope of the present application, even if the molar ratio of the porous iron powder is "excessive", complete separation of the residual excessive iron powder from the product could be achieved.
Comparative example 1: compared with examples 1-5, the average particle size D50 of the porous iron powder is smaller than 50 mu m, the residual iron powder cannot be well separated and decontaminated in the air flow grinding stage by utilizing the particle size difference, and the content of alpha-Fe in the final magnetic powder is high, the magnetic performance is poor, and particularly, the Hcj and BHmax are obviously inferior to those of examples 1-5;
comparative example 2: compared with examples 1-5, the average particle size D50 of the porous iron powder is more than 150 mu m, so that the fine-particle samarium oxide cannot completely wrap the oversized iron powder, the porosity of the porous iron powder is less than 25%, the reduced metal samarium does not penetrate into the iron powder sufficiently, and Sm is not completely formed in the product after reaction 2 Fe 17 The small granularity alpha-Fe core of the alloy causes higher iron content and poorer magnetic performance, particularly Hcj and BHmax, which are obviously inferior to those of examples 1-5;
comparative example 3: and example 1 to the extent5, compared with the prior art, the prepared Sm adopts spherical iron powder 2 Fe 17 N 3 The alpha-Fe impurity content in the magnetic powder is obviously higher, the magnetic performance is poorer, and particularly, the Hcj and BHmax are obviously inferior to those of examples 1-5;
comparative example 4: in comparison with examples 1 to 5, the porous iron powder has a porosity of more than 40%, resulting in too much samarium element being filled in the pores to participate in Sm 2 Fe 17 The samarium content of the synthesis reaction is insufficient, resulting in the Sm 2 Fe 17 N 3 The residual magnetism and coercive force of the magnetic powder are obviously lower than those of the examples 1 to 5;
comparative example 5: compared with examples 1 to 5, the average particle size D50 of the samarium oxide powder was 10. Mu.m, which was not in the range of 0.5 to 4. Mu.m, the reduction was incomplete, and there was insufficient samarium metal to participate in Sm 2 Fe 17 The synthetic reaction of the method has large granularity of samarium oxide, and cannot form good wrapping form on raw material iron powder, so that the diffusion of the metal samarium into the iron powder is insufficient, and the prepared Sm is caused 2 Fe 17 N 3 The residual magnetism and coercive force of the magnetic powder are significantly lower than those of examples 1 to 5.
Comparative example 6: compared with examples 1-5, the average particle size D50 of the porous iron powder is less than 50 mu m, and the residual iron powder cannot be well separated and decontaminated in the air flow grinding stage by utilizing the particle size difference; meanwhile, the formulation of comparative example 6 has a higher iron powder content than that of comparative example 1, resulting in the Sm being produced 2 Fe 17 N 3 The content of residual alpha-Fe in the magnetic powder is also higher; and the magnetic properties, particularly Hcj and BHmax, are far inferior to those of examples 1 to 5.
While specific embodiments of the application have been described above, it will be appreciated by those skilled in the art that this is by way of example only, and the scope of the application is defined by the appended claims. Various changes and modifications to these embodiments may be made by those skilled in the art without departing from the principles and spirit of the application, but such changes and modifications fall within the scope of the application.

Claims (10)

1. A preparation method of samarium-iron alloy is characterized in thatThe preparation method of the samarium-iron alloy comprises the following steps: sm is to 2 O 3 Fe and Ca are subjected to reduction diffusion reaction and crushing treatment;
wherein said Sm 2 O 3 The average particle size D50 of (2) is 0.5-4 mu m;
the average particle size D50 of Fe is 50-150 mu m; the porosity of Fe is 10% -40%.
2. The method of claim 1, wherein said Sm is 2 O 3 The average particle size D50 of (2) is 1-2 mu m;
and/or, the Fe is porous iron powder or foam iron powder; the average particle size D50 of Fe is preferably 80-120 μm; the porosity of Fe is preferably 25-40%;
and/or, the Ca is metallic calcium; the physical form of the metal calcium is preferably metal calcium particles; the particle size of the metal calcium particles is preferably 1-2 mm;
and/or, the Sm 2 O 3 The Fe and the Ca are as per Sm 2 O 3 +17Fe+3Ca=Sm 2 Fe 17 Determining the material ratio by a reaction equation of +3CaO;
wherein, the Ca is proportioned according to 1.05 to 1.5 times of the theoretical quantity determined by the reaction equation; the Sm is 2 O 3 Batching according to 1.05-1.3 times of the theoretical amount determined by the reaction equation;
preferably, the Sm 2 O 3 And the molar ratio of Fe is 1: (13-17), for example 1:16.2;
preferably, the Sm 2 O 3 And the molar ratio of Ca is 1: (2 to 5), for example, 1:2.4,1:3 or 1:4.3.
3. the method of manufacturing a samarium-iron alloy according to claim 1, characterized in that the reduction-diffusion reaction comprises a reduction process and a diffusion process;
preferably, in the reduction diffusion reaction, the reaction temperature and the reaction time of the reduction process and the diffusion process are the same or different;
when the reaction temperatures of the reduction process and the diffusion process are the same, the reaction temperatures of the reduction process and the diffusion process are independently 1050 to 1180 ℃, e.g., 1120 ℃ or 1140 ℃; the reaction time of the reduction process and the diffusion process is independently 2 to 13 hours, for example 5 hours, 6 hours, 8 hours, 9 hours or 10 hours;
when the reaction temperatures of the reduction process and the diffusion process are different, the reaction temperature of the reduction process is 850 to 950 ℃, preferably 900 ℃, and the reaction time of the reduction process is 1 to 5 hours, for example 2 hours or 3 hours; the reaction temperature of the diffusion process is 1050-1180 ℃, such as 1100 ℃, 1120 ℃, 1140 ℃, 1150 ℃ or 1160 ℃, and the reaction time of the diffusion process is 2-10 hours, such as 4 hours, 6 hours or 8 hours;
and/or, the reduction diffusion reaction is carried out according to the following steps: the reduction process is to keep the mixture A at 850-950 ℃ for 1-5 h to lead Sm to be 2 O 3 Fully reducing to obtain a mixed material B; the mixed material A is Sm 2 O 3 Fe and Ca; the diffusion process is that the mixed material B is kept for 2 to 10 hours at 1050 to 1180 ℃ to lead the metal Sm to diffuse into Fe powder and form samarium-iron alloy;
and/or the reduction and diffusion reaction is carried out under the protection of inert gas; the inert gas is preferably argon.
4. The method of manufacturing a samarium-iron alloy according to claim 1, characterized in that the crushing treatment comprises coarse crushing, jet milling and hydrogen crushing;
wherein, the coarse crushing is preferably jaw crushing or disc grinding crushing; after the coarse crushing, the samarium-iron alloy preferably has an average particle diameter D50 of <2mm;
wherein, the jet milling is preferably to crush and sort the crude crushed samarium-iron alloy by adopting a jet mill, so that the agglomerated product after the reaction is crushed and dispersed; after the jet milling, the average grain diameter D50 of the samarium-iron alloy is preferably 0.5-25 mu m;
wherein the hydrogen disruption is preferably performed in a vacuum hydrogen disruption furnace;
the hydrogen breakage is preferably between 500 and 900mbar H 2 In a gaseous atmosphere;
preferably, the hydrogen disruption is performed according to the following process: the samarium iron alloy after jet milling is subjected to hydrogen absorption for 2 to 5 hours at the temperature of between 150 and 250 ℃ and is subjected to vacuum pumping for dehydrogenation at the temperature of between 250 and 350 ℃.
5. A samarium iron alloy characterized in that the samarium iron alloy is produced by the production method of the samarium iron alloy according to any one of claims 1 to 4;
the samarium-iron alloy is preferably in a powder form;
the samarium iron alloy preferably has an average particle diameter D50 of 0.2 to 4. Mu.m, for example, 1.7. Mu.m, 1.8. Mu.m, 2.1. Mu.m, 2.3. Mu.m, or 2.5. Mu.m.
6. The use of the samarium-iron alloy according to claim 5 for the preparation of samarium-iron-nitrogen permanent magnet materials.
7. The preparation method of the samarium-iron-nitrogen permanent magnet material is characterized by comprising the following steps of: the samarium-iron alloy according to claim 5 is subjected to nitriding treatment.
8. The method of preparing samarium-iron-nitrogen permanent magnet material according to claim 7, characterized in that the nitriding treatment is performed at a temperature of 450-550 ℃, such as 480 ℃, 500 ℃ or 520 ℃;
and/or the nitriding treatment has a pressure of 0.09MPa to 1.5MPa, for example 0.2MPa, 0.5MPa, 0.8MPa, 0.9MPa, 1MPa, 1.2MPa or 1.5MPa;
and/or the nitriding treatment is carried out for 4 to 20 hours, such as 5 hours, 6 hours, 10 hours, 12 hours or 15 hours;
and/or the medium for nitriding is N 2 、NH 3 、N 2 +H 2 Mixed gas of (2), N 2 +NH 3 Mixed gas of (2) NH 3 +H 2 Or, N 2 +NH 3 +H 2 Is a mixed gas of (a) and (b);
and/or, after the nitriding treatment, the method further comprises the steps of washing with water and drying;
wherein the water washing solution used for water washing is preferably water; the method further comprises the step of dehydration treatment after the water washing; the solvent for dehydration treatment is an organic solvent; the organic solvent is preferably alcohol or acetone;
wherein the drying process is preferably vacuum drying; preferably, after said drying, further comprising the steps of air flow dispersion and classification; the air flow dispersing and classifying process preferably adopts an air flow mill;
more preferably, the product is subjected to simultaneous antioxidant and dispersing treatments during the gas stream dispersing and classifying process;
the antioxidation treatment is preferably carried out by adding an organic antioxidant during the jet milling process; the addition amount of the organic antioxidant is preferably 0.2 to 2.5%, for example 0.5%;
the dispersion treatment is preferably carried out by adding a dispersing agent during the air-jet milling process; the addition amount of the dispersant is preferably 0.2 to 2.5%, for example 0.5%;
preferably, the sum of the addition amounts of the organic antioxidant and the dispersant is 0.8 to 4.0%, for example 1% or 1.5%.
9. The samarium-iron-nitrogen permanent magnet material is characterized in that the samarium-iron-nitrogen permanent magnet material is prepared by adopting the preparation method of the samarium-iron-nitrogen permanent magnet material according to claim 7 or 8;
the samarium iron nitrogen permanent magnet material preferably has an average particle diameter D50 of 0.2 to 4 μm, for example 1.7 μm, 1.8 μm, 2.1 μm, 2.3 μm or 2.5 μm.
10. Use of the samarium-iron-nitrogen permanent magnet material according to claim 9 as an electromagnetic element.
CN202210232108.8A 2022-03-04 2022-03-04 Samarium-iron alloy, samarium-iron-nitrogen permanent magnet material, and preparation methods and applications thereof Pending CN116741484A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117245088A (en) * 2023-11-16 2023-12-19 西安稀有金属材料研究院有限公司 Auxiliary agent auxiliary preparation method for samarium iron and samarium iron nitrogen

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117245088A (en) * 2023-11-16 2023-12-19 西安稀有金属材料研究院有限公司 Auxiliary agent auxiliary preparation method for samarium iron and samarium iron nitrogen

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