A samarium-iron alloy, a samarium-iron-nitrogen permanent magnet material and a manufacturing method and application thereof

Abstract

The application discloses a kind of samarium iron alloy, samarium iron nitrogen permanent magnet material and manufacturing method, application.The manufacturing method of the samarium iron alloy includes the following steps: (1) in protective atmosphere A, mixture A is treated by first heat preservation, and mixture B is obtained;The temperature of the first heat preservation is 800-950 DEG C;The time of the first heat preservation is 1-5 hours;The mixture A includes Sm2O3, Fe and Ca;(2) in protective atmosphere B, the mixture B is treated by second heat preservation, and the samarium iron alloy is obtained;The temperature of the second heat preservation is 1050-1180 DEG C;The time of the second heat preservation is 2-10 hours.The samarium iron nitrogen magnetic powder prepared in the application has the characteristics of low iron impurity content, low calcium and oxygen content, and high magnetic performance.Moreover, the manufacturing method of the application is efficient, low-cost, simple to prepare, and can use large-size porous iron powder, with low material cost.

Description

Technical Field

[0001] This invention relates to a samarium iron alloy, a samarium iron nitrogen permanent magnet material, its manufacturing method, and its application. Background Technology

[0002] Iron-nitrogen-based rare-earth permanent magnet materials possess temperature stability comparable to samarium-cobalt. Their main components, samarium and iron, result in lower manufacturing costs, and minimal fluctuations in raw material prices make them an ideal choice for cost-effective permanent magnets in downstream applications. Iron-nitrogen-based rare-earth permanent magnet materials theoretically exhibit excellent magnetic properties. Based on the interstitial atom effect of nitrogen in rare-earth-transition metal compounds, their Curie temperature is more than 100°C higher than that of neodymium-iron-boron materials, making them a significant research hotspot in the field of rare-earth permanent magnets in recent years. (The text abruptly shifts to a seemingly unrelated topic about Sm2Fe...) 17 N3 magnetic powder exhibits high coercivity only when the grain size is no larger than that of uniaxial particles. In order to obtain fine grain structure economically and efficiently, the industry usually adopts melt quenching method, hydrogen disproportionation method, mechanical alloying method (e.g., CN1202537C), rapid solidification casting method (e.g., CN106312077B) or reduction diffusion method (e.g., CN1424165A). Among them, the reduction diffusion method has attracted the attention of researchers due to its advantages such as simple equipment, low raw material cost and easy implementation of process conditions.

[0003] However, existing reduction-diffusion methods for preparing samarium-iron-nitrogen magnetic powder suffer from drawbacks such as excessive samarium volatilization and impaired diffusion reaction. Existing patent CN 108274016 A discloses a method for directly preparing samarium-iron alloy powder using a spray thermal decomposition reduction method. In this method, the molar ratio of samarium to iron in the samarium-iron alloy is easily adjusted by the ratio of samarium salt to iron salt in the precursor solution. During reduction-diffusion, samarium and iron exhibit good dispersion, low reduction temperature, and short reaction time, effectively reducing samarium volatilization and inhibiting samarium-iron alloy powder agglomeration. While this existing patent reduces samarium volatilization, its process is complex; furthermore, it carries risks such as incomplete Sm₂O₃ reduction, insufficient Sm-Fe interdiffusion, and unstable magnet performance.

[0004] Therefore, how to provide a preparation process that can effectively reduce the excessive volatilization of samarium during the manufacturing process of samarium-iron-nitrogen permanent magnet materials while ensuring the performance of the magnet is an urgent technical problem to be solved in this field. Summary of the Invention

[0005] The technical problem this invention aims to solve is to overcome the shortcomings of existing reduction-diffusion methods in the preparation of samarium-iron-nitrogen magnetic powder. These methods either suffer from excessive samarium volatilization, hindering the complete diffusion reaction, or from complex processes and unstable magnetic properties. This invention provides a samarium-iron alloy, samarium-iron-nitrogen permanent magnet material, its manufacturing method, and its applications. The reduction-diffusion process in this invention overcomes the excessive samarium volatilization defect caused by existing reduction-diffusion processes, while simultaneously promoting a complete diffusion reaction. The resulting samarium-iron-nitrogen magnetic powder is characterized by low iron impurity content, low calcium and oxygen content, and high magnetic properties. Furthermore, the manufacturing method of this invention is efficient, low-cost, and simple, and can utilize large-particle porous iron powder, resulting in low material costs.

[0006] This invention provides a method for manufacturing a samarium-iron alloy, comprising the following steps:

[0007] (1) Mixture A is subjected to a first heat treatment in a protective atmosphere A to obtain mixture B;

[0008] In the protective atmosphere A, the gas pressure (P1) ≤ 700 mbar;

[0009] The temperature (T1) of the first heat preservation treatment is 800-950℃;

[0010] The duration (t1) of the first heat preservation treatment is 1-5 hours;

[0011] The mixture A contains Sm2O3, Fe and Ca;

[0012] (2) The mixture B is subjected to a second heat treatment in a protective atmosphere B to obtain the samarium-iron alloy;

[0013] In the protective atmosphere B, the gas pressure (P2) is ≤1000 mbar; the gas pressure in the protective atmosphere B minus the gas pressure in the protective atmosphere A is >200 mbar.

[0014] The temperature (T2) of the second heat preservation treatment is 1050-1180℃;

[0015] The second heat preservation treatment time (t2) is 2-10 hours.

[0016] Although excessive samarium volatilization can be overcome by lowering the temperature, this leads to insufficient thermodynamic driving force for the reaction, preventing complete reduction. Furthermore, insufficient diffusion motive force limits the diffusion depth of Sm into the Fe powder, resulting in Sm₂Fe forming only on the outer layer of the Fe powder. 17 Sm2Fe cannot be formed in the shell and core of Fe powder. 17In this phase, the core-shell structure with an Fe core, due to the high strength and toughness of the Fe core, will prevent the subsequent powder from being broken down, and will also introduce a large amount of α-Fe into the magnetic powder, causing a significant reduction in the performance of the magnetic powder. For example, as shown in Comparative Example 1 of this invention, when the reduction diffusion temperature is lowered to about 1000-1050℃ (e.g., 1020℃), the magnetic properties are poor, and the α-Fe content and oxygen content are high.

[0017] This invention creatively sets the reduction reaction temperature above the melting point of metallic calcium (850°C under one atmosphere) and below the melting point of metallic samarium (1072°C under one atmosphere). Within this temperature range, the metallic calcium particles melt and exist in a liquid state, greatly increasing the contact area between the materials. The liquid metallic calcium can fully react with Sm₂O₃ powder, reducing Sm₂O₃ to metallic samarium. Simultaneously, within this temperature range (800-950°C, gas pressure ≤700 mbar), metallic samarium does not melt, and its volatilization is extremely low, thus ensuring sufficient samarium content participates in the subsequent diffusion process (under protective atmosphere A, the melting point of metallic calcium is approximately 750-800°C, and the melting point of metallic samarium is between 950-1000°C).

[0018] When the first and second heat preservation treatments are carried out continuously, as the temperature rises, the gas (e.g., argon) in protective atmosphere A will further expand (forming protective atmosphere B), thereby increasing the pressure and raising the vapor pressure of samarium. Under the pressure conditions of protective atmosphere B, the melting point of samarium is approximately 1040-1050℃. Therefore, at diffusion reaction temperatures between 1050-1180℃, samarium can be converted into a liquid form. When the raw material contains porous iron powder, samarium can rapidly diffuse from the pores of the porous iron powder into the interior of the iron powder, forming Sm2Fe. 17 Alloy. Within this temperature range, due to the presence of atmospheric pressure, samarium volatilization is low, which is conducive to the complete progress of the diffusion reaction.

[0019] In step (1), the protective atmosphere A can be a conventional protective atmosphere in the art, such as an argon atmosphere.

[0020] In step (1), the first heat preservation treatment can be carried out in a vacuum heat treatment furnace.

[0021] During the process of raising the temperature from room temperature to 800-950℃, the vacuum level in the vacuum heat treatment furnace can be maintained at <0.1Pa.

[0022] When the mixture A is heated to 800-950°C, high-purity argon gas can be introduced into the vacuum heat treatment furnace.

[0023] In step (1), the gas pressure in the protective atmosphere A is preferably ≤680mbar, for example 400-680mbar, or even 440mbar, 480mbar, 492mbar, 500mbar, 540mbar or 640mbar.

[0024] In step (1), the temperature of the first heat preservation treatment is preferably 850-950℃, such as 850℃, 900℃, 930℃ or 950℃.

[0025] In step (1), the first heat preservation treatment time is preferably 2-5 hours, for example 2 hours, 3 hours or 5 hours.

[0026] In step (1), preferably, the temperature of the first heat preservation treatment is 900-950℃, and the time of the first heat preservation treatment is 1-3 hours.

[0027] In step (1), preferably, the temperature of the first heat preservation treatment is 850°C, and the time of the first heat preservation treatment is 2-5 hours, for example, 5 hours.

[0028] In step (1), preferably, the temperature of the first heat preservation treatment is 900°C and the time of the first heat preservation treatment is 2-3 hours.

[0029] In step (1), preferably, the temperature of the first heat preservation treatment is 930°C and the time of the first heat preservation treatment is 2 hours.

[0030] In step (1), preferably, the temperature of the first heat preservation treatment is 950°C and the time of the first heat preservation treatment is 1-2 hours.

[0031] In step (1), after the first heat preservation treatment, the mixture A can melt the metallic calcium and reduce Sm2O3 to metallic samarium, and the metallic samarium does not melt.

[0032] In step (1), preferably, the gas pressure P1 (mbar) in the protective atmosphere A, the temperature T1 (°C) of the first heat preservation treatment, and the time t1 (h) of the first heat preservation treatment satisfy the following conditions: P1 (gas pressure / mbar) = α1*T1 (temperature / °C) + β1*t1 (time / h), where: α1 is 0.1-1.0, and β1 is 50-70.

[0033] Preferably, α1 is 0.1-0.5, for example 0.4.

[0034] Preferably, β1 is 55-65, for example 60.

[0035] Preferably, the gas pressure P1 (mbar) in the protective atmosphere A, the temperature T1 (°C) of the first heat preservation treatment, and the time t1 (h) of the first heat preservation treatment satisfy the following conditions:

[0036] P1 (air pressure / mbar) = 0.4 * T1 (temperature / ℃) + 60 * t1 (time / h).

[0037] In step (1), the Fe can be in the form of iron powder that is conventional in the art, such as reduced iron powder, spherical iron powder or porous iron powder.

[0038] The particle size of the reduced iron powder can be 0.5-40 μm (D50), for example 15 μm, 25 μm or 40 μm.

[0039] The reduced iron powder is a gray or black powder mainly containing elemental iron. It is generally a loose iron powder produced by reducing iron(III) oxide under high heat in a hydrogen or carbon monoxide stream.

[0040] The density of the reduced iron powder can be 6.5 g / cm³. 3 .

[0041] The reduced iron powder can be purchased from Guangzhou Metal Metallurgy Co., Ltd.

[0042] The particle size of the spherical iron powder can be 0.5-40 μm (D50), for example, 0.5 μm, 5 μm or 10 μm.

[0043] The spherical iron powder mentioned above generally refers to iron powder with a dense spherical shape.

[0044] The density of the spherical iron powder can be 7.8 g / cm³. 3 .

[0045] The spherical iron powder can be purchased from MCC Xindun Company.

[0046] The particle size of the porous iron powder is preferably 50-150 μm (D50), for example 80 μm, 115 μm or 150 μm.

[0047] The porosity of the porous iron powder is preferably 10%-40%, for example 15%, 25% or 35%.

[0048] In this invention, porosity refers to the percentage of pore volume in a bulk material to the total volume of the material in its natural state (generally, without external force).

[0049] The porous iron powder may be foamed iron powder.

[0050] The porous iron powder can be purchased from SJM Technology Co., Ltd.

[0051] In step (1), the Sm2O3 can be a conventional Sm2O3 morphology in the art, and the particle size of the Sm2O3 can be 0.1-10μm (D50), for example 0.5μm (D50), 2.5μm (D50), 4μm (D50), 5μm (D50) or 6μm (D50).

[0052] In step (1), the Sm2O3, the Fe, and the Ca can be expressed as Sm2O3 + 17Fe + 3Ca = Sm2Fe 17 The reaction equation for +3CaO determines the material ratio.

[0053] To ensure sufficient reduction of samarium oxide, the amount of metallic Ca is generally prepared at 1.05-1.5 times the theoretical amount determined by the equation (5%-50% excess). Meanwhile, considering the volatilization of metallic Sm during the reduction diffusion reaction at high temperature, Sm2O3 is generally prepared at 1.05-1.3 times the theoretical amount determined by the above equation (5%-30% excess).

[0054] In step (2), the protective atmosphere B can be a conventional protective atmosphere in the art, such as an argon atmosphere.

[0055] In step (2), the second heat preservation treatment can be carried out in a vacuum heat treatment furnace.

[0056] In step (2), the gas pressure in the protective atmosphere B is preferably ≤950mbar, for example 750-950mbar, or even 755mbar, 844mbar, 845mbar, 846mbar, 850mbar, 851mbar, 852mbar, 885mbar or 926mbar.

[0057] In this invention, preferably, the gas pressure in the protective atmosphere B minus the gas pressure in the protective atmosphere A is 201-450 mbar, that is, the difference between the gas pressures in the protective atmosphere B and the protective atmosphere A is 201-450 mbar, for example 210 mbar, 255 mbar, 286 mbar, 304 mbar, 311 mbar, 345 mbar, 353 mbar, 372 mbar or 406 mbar.

[0058] In step (2), the temperature of the second heat preservation treatment is preferably 1100-1180℃, for example 1100℃, 1120℃, 1130℃, 1150℃, 1160℃ or 1180℃.

[0059] In step (2), the second heat preservation treatment time is preferably 4-10 hours, for example 4 hours, 6 hours, 8 hours or 10 hours.

[0060] In step (2), preferably, the temperature of the second heat preservation treatment is 1050-1160℃, and the time of the second heat preservation treatment is 2-6 hours.

[0061] In step (2), preferably, the temperature of the second heat preservation treatment is 1050°C, and the time of the second heat preservation treatment is 2-10 hours, for example, 2 hours or 10 hours.

[0062] In step (2), preferably, the temperature of the second heat preservation treatment is 1100℃ and the time of the second heat preservation treatment is 8 hours.

[0063] In step (2), preferably, the temperature of the second heat preservation treatment is 1120°C and the time of the second heat preservation treatment is 6 hours.

[0064] In step (2), preferably, the temperature of the second heat preservation treatment is 1130°C and the time of the second heat preservation treatment is 6 hours.

[0065] In step (2), preferably, the temperature of the second heat preservation treatment is 1150°C and the time of the second heat preservation treatment is 4 hours.

[0066] In step (2), preferably, the temperature of the second heat preservation treatment is 1160°C and the time of the second heat preservation treatment is 4 hours.

[0067] In step (2), preferably, the temperature of the second heat preservation treatment is 1180°C, and the time of the second heat preservation treatment is 2-10 hours, for example, 2 hours or 10 hours.

[0068] In step (2), preferably, the gas pressure P2 (mbar) in the protective atmosphere B, the temperature T2 (°C) of the second heat preservation treatment, and the time t2 (h) of the second heat preservation treatment satisfy the following condition: P2 (gas pressure / mbar) = α2*T2 (temperature / °C) + β2*t2 (time / h), where: α2 is 0.1-1.0, and β2 is 1-20.

[0069] Preferably, α2 is 0.6-0.8, for example 0.7.

[0070] Preferably, β2 is 5-15, for example 10.

[0071] Preferably, the gas pressure P2 (mbar) in the protective atmosphere B, the temperature T2 (°C) of the second heat preservation treatment, and the time t2 (h) of the second heat preservation treatment satisfy the following conditions:

[0072] P2 (air pressure / mbar) = 0.7 * T2 (temperature / ℃) + 10 * t2 (time / h).

[0073] In step (2), after the second heat preservation treatment, the particle size of the mixture B can be 2-25 μm.

[0074] In step (2), the samarium iron alloy generally refers to Sm2Fe 17 alloy.

[0075] In step (2), the samarium metal obtained by the reduction reaction in step (1) is in liquid state.

[0076] In step (2), after the second heat preservation treatment, metal Sm and Fe can react to form Sm2Fe. 17 alloy.

[0077] When the Fe is porous iron powder, metallic Sm can diffuse into the porous iron powder and form Sm2Fe. 17 The alloy spontaneously breaks down into alloy powder of 2-25 μm.

[0078] In the present invention, in the method for manufacturing the samarium-iron alloy, the gas pressure of the protective atmosphere A, the temperature of the first heat treatment, the time of the first heat treatment, the gas pressure of the protective atmosphere B, the temperature of the second heat treatment, and the time of the second heat treatment satisfy one of the following conditions:

[0079]

[0080]

[0081] In step (2), the samarium-iron alloy may also undergo post-processing steps such as coarse crushing, air jet milling, and hydrogen crushing.

[0082] The coarse crushing generally employs mechanical crushing, such as jaw crushing or disc mill crushing.

[0083] After coarse crushing, the particle size of the samarium-iron alloy is generally <2mm.

[0084] The air jet mill is generally used for crushing and sorting to break down and disperse the agglomerated products after the reaction.

[0085] The samarium-iron alloy can have a particle size of 0.5-25 μm after air jet pulverization.

[0086] The air jet milling process can separate large iron powder particles (>25μm) that have not fully reacted from the product, resulting in a mixed product that does not contain iron powder.

[0087] The hydrogen crushing mentioned above generally refers to crushing using H2.

[0088] The hydrogen crushing can be carried out in a vacuum hydrogen crushing furnace.

[0089] The hydrogen decomposition can be carried out according to the following process: the samarium-iron alloy is subjected to hydrogen absorption at 150-250℃ for 2-6 hours, and then dehydrogenated by vacuuming at 250-350℃.

[0090] The samarium-iron alloy may be a samarium-iron alloy that has been pulverized by air jet milling.

[0091] The hydrogen crushing can be carried out in an atmosphere of 500-900 mbar (e.g., 800 mbar) H2 gas.

[0092] The temperature for hydrogen absorption can be 150-240℃, for example, 150℃, 200℃, 220℃, 225℃, 230℃ or 240℃.

[0093] The hydrogen absorption time can be 4-6 hours, for example, 5 hours.

[0094] The dehydrogenation temperature can be 280-350℃, for example 280℃, 300℃, 320℃ or 350℃.

[0095] The hydrogen breakage can cause Sm2Fe in the mixed product to be broken down. 17 The alloy undergoes hydrogen absorption and breakage, causing the remaining metallic Ca layer adhering to the product surface to transform into CaH2, which then pulverizes and peels off.

[0096] The present invention also provides a method for manufacturing a samarium-iron alloy, comprising the following steps:

[0097] (1) Mixture A is subjected to a first heat treatment in a protective atmosphere A to obtain mixture B;

[0098] In the protective atmosphere A, the gas pressure is P1 mbar;

[0099] The temperature of the first heat preservation treatment is T1℃;

[0100] The duration of the first heat preservation treatment is t1 hours;

[0101] The mixture A contains Sm2O3, Fe and Ca;

[0102] The P1 (mbar), T1 (°C), and t1 (h) satisfy the following condition: P1 (bar pressure) = α1 * T1 (°C) + β1 * t1 (h), where α1 is 0.1-1.0 and β1 is 50-70.

[0103] (2) The mixture B is subjected to a second heat treatment in a protective atmosphere B to obtain the samarium-iron alloy;

[0104] In the protective atmosphere B, the gas pressure is P2 mbar; P2-P1>200mbar;

[0105] The temperature of the second heat preservation treatment is T2℃;

[0106] The second heat preservation treatment time is t2 hours;

[0107] The P2 (mbar), T2 (°C), and t2 (h) satisfy the following condition: P2 (air pressure / mbar) = α2 * T2 (temperature / °C) + β2 * t2 (time / h), where: α2 is 0.1-1.0, and β2 is 1-20.

[0108] In step (1), the type and pressure of the protective atmosphere A can be as described above.

[0109] In step (1), the temperature and time of the first heat preservation treatment can be as described above.

[0110] In step (1), α1 and β1 can be as described above.

[0111] In step (1), the Fe can be in the form described above.

[0112] In step (2), the type and pressure of the protective atmosphere B can be as described above.

[0113] In step (2), the temperature and time of the second heat preservation treatment can be as described above.

[0114] In step (2), α2 and β2 can be as described above.

[0115] In step (2), the post-processing of the samarium-iron alloy can be as described above.

[0116] The present invention also provides a method for manufacturing a samarium-iron alloy, comprising the following steps:

[0117] (1) Mixture A is subjected to a first heat treatment in a protective atmosphere A to obtain mixture B;

[0118] In the protective atmosphere A, the gas pressure is P1 mbar;

[0119] The temperature of the first heat preservation treatment is T1℃;

[0120] The duration t1 of the first heat preservation treatment is 1-5 hours;

[0121] The mixture A contains Sm2O3, Fe and Ca;

[0122] The P1 (mbar), T1 (°C), and t1 (h) satisfy the following conditions: during the first heat preservation treatment, metallic calcium melts and reduces Sm2O3 to metallic samarium, and the metallic samarium does not melt;

[0123] (2) The mixture B is subjected to a second heat treatment in a protective atmosphere B to obtain the samarium-iron alloy;

[0124] In the protective atmosphere B, the gas pressure is P2 mbar; P2-P1>200mbar;

[0125] The temperature of the second heat preservation treatment is T2℃;

[0126] The second heat preservation treatment time t2 is 2-10 hours;

[0127] The P2 (mbar), T2 (°C), and t2 (h) satisfy the following conditions: during the second heat preservation treatment, samarium metal is in a liquid state; after the second heat preservation treatment, samarium metal Sm reacts with Fe to generate Sm2Fe. 17 alloy.

[0128] In step (1), the type and pressure of the protective atmosphere A can be as described above.

[0129] In step (1), the temperature and time of the first heat preservation treatment can be as described above.

[0130] In step (1), P1 (mbar), T1 (°C), and t1 (h) can satisfy the following conditions: P1 (air pressure / mbar) = α1*T1 (temperature / °C) + β1*t1 (time / h), where: α1 is 0.1-1.0, and β1 is 50-70.

[0131] The α1 and β1 can be as described above.

[0132] In step (1), the Fe can be in the form described above.

[0133] In step (2), the type and pressure of the protective atmosphere B can be as described above.

[0134] In step (2), the temperature and time of the second heat preservation treatment can be as described above.

[0135] In step (2), P2 (mbar), T2 (°C), and t2 (h) can satisfy the following conditions: P2 (air pressure / mbar) = α2*T2 (temperature / °C) + β2*t2 (time / h), where: α2 is 0.1-1.0, and β2 is 1-20.

[0136] The α2 and β2 can be as described above.

[0137] In step (2), the post-processing of the samarium-iron alloy can be as described above.

[0138] The present invention also provides a samarium-iron alloy, which is prepared by the above method.

[0139] The present invention also provides Sm2Fe 17 The alloy contains 23-27 wt% Sm, ≤0.64 wt% α-Fe, ≤1.32 wt% oxygen, ≤0.1 wt% calcium, and the balance is Fe.

[0140] Wherein, wt% refers to the content of Sm2Fe 17 Weight percentage in the alloy.

[0141] The present invention also provides a method for manufacturing samarium iron nitride permanent magnet material, which includes the following steps: nitriding the samarium iron alloy.

[0142] The nitriding temperature can be a conventional nitriding temperature in the art, such as 450-550°C, or even 450°C, 480°C, 500°C, 520°C or 550°C.

[0143] The nitriding pressure can be a conventional nitriding pressure in the art, such as 0.09MPa-1.5MPa, or even 0.09MPa, 0.2MPa, 0.5MPa, 0.8MPa, 0.9MPa, 1.0MPa, 1.2MPa or 1.5MPa.

[0144] The nitriding medium can be a conventional nitriding medium in the art, such as N2 or NH3, or for example, "a mixture of N2 and H2", "a mixture of NH3 and H2", or "a mixture of N2, NH3 and H2".

[0145] The nitriding time can be a conventional nitriding time in the art, for example, nitriding for 4-20 hours under conditions of 0.09-1.5 MPa.

[0146] The nitriding time can be 5-20 hours, for example, 5 hours, 6 hours, 10 hours, 12 hours, 15 hours or 20 hours.

[0147] In the nitriding process, Sm2Fe 17 Alloy nitriding forms Sm2Fe 17 N3 compounds.

[0148] The nitriding process typically includes washing, drying, and pulverizing.

[0149] The water washing can remove impurities such as CaO, Ca, and CaH2 from the mixed product.

[0150] During the water washing process, a small amount of weak acid such as acetic acid can be added to maintain the pH of the water washing solution at 6 or higher.

[0151] After washing with water, the product can be dehydrated using organic solvents such as alcohol or acetone.

[0152] The drying process can be carried out under vacuum conditions.

[0153] The pulverization can be performed by air jet milling in a nitrogen or argon atmosphere. The pulverization can break up and disperse the dried and agglomerated product.

[0154] During the pulverization process, organic antioxidants and / or dispersants can be added to treat the magnetic powder for oxidation and / or dispersion.

[0155] The organic antioxidant may be a type of conventional organic antioxidant in the art, such as one or more of butylated hydroxytoluene, tert-butylhydroquinone, 2,6-di-tert-butyl-p-cresol, and N,N-di-sec-butyl-p-phenylenediamine, and also, for example, N,N-di-sec-butyl-p-phenylenediamine.

[0156] The organic antioxidant can be added during the air jet milling process.

[0157] The amount of the organic antioxidant added is preferably 0.2-2.5%, for example 0.4%, where the percentage refers to the mass percentage of the organic antioxidant in the samarium iron nitrogen permanent magnet material.

[0158] The dispersant may be a type of dispersant commonly used in the art, such as one or more of cyclohexane, n-heptane, and 120# solvent oil, or 120# solvent oil.

[0159] The dispersant can be added during the air jet milling process.

[0160] The amount of the dispersant added is preferably 0.2-2.5%, for example 0.55%, where the percentage refers to the mass percentage of the dispersant in the samarium iron nitrogen permanent magnet material.

[0161] The sum of the amounts of the organic antioxidant and the dispersant is preferably 0.8-4.0%, for example 1.5% or 0.95%, where the percentage refers to the mass percentage of the sum of the amounts in the samarium iron nitrogen permanent magnet material.

[0162] After being pulverized, the samarium iron nitrogen permanent magnet material powder (Sm2Fe) 17The particle size of N3 magnetic powder can be around 0.2-4μm, for example 0.3μm, 1.7μm, 1.8μm, 2.2μm, 2.5μm, 2.5μm, 3.3μm, 3.7μm or 3.8μm.

[0163] The present invention also provides a samarium iron nitrogen permanent magnet material, which is prepared by the above method.

[0164] The present invention also provides a samarium iron nitrogen permanent magnet material, wherein the content of Sm is 23-27wt%, the content of α-Fe is ≤0.64wt%, the content of oxygen is ≤1.32wt%, the content of calcium is ≤0.1wt%, and the balance is Fe and N (nitrogen).

[0165] Wherein, wt% refers to the weight percentage of the samarium iron nitrogen permanent magnet material.

[0166] The content of Sm can be 24-26 wt%, for example 24.2 wt%, 24.5 wt%, 24.5 wt%, 24.8 wt%, 24.9 wt%, 24.9 wt%, 25 wt%, 25.1 wt%, or 25.3 wt%.

[0167] The α-Fe content can be 0.12-0.64 wt%, for example 0.12 wt%, 0.18 wt%, 0.35 wt%, 0.35 wt%, 0.37 wt%, 0.51 wt%, 0.54 wt%, 0.58 wt%, or 0.64 wt%.

[0168] The oxygen content can be 0.76-1.32 wt%, for example 0.76 wt%, 0.83 wt%, 0.85 wt%, 0.85 wt%, 0.89 wt%, 0.91 wt%, 0.92 wt%, 1.04 wt%, or 1.32 wt%.

[0169] The calcium content may be ≤0.05wt%, for example, 0.03wt%, 0.04wt%, or 0.05wt%.

[0170] The present invention also provides an application of the samarium iron nitrogen permanent magnet material as an electromagnetic component.

[0171] In this invention, the pressure corresponding to the vacuum degree and the pressure of each gas refer to absolute pressure, that is, pressure expressed with absolute vacuum as the reference.

[0172] In this invention, the terms "first," "second," etc., are used to describe various heat treatments, and these heat treatments should not be limited by these terms. These terms are only used to distinguish one heat treatment from another.

[0173] Based on common knowledge in the field, the above-mentioned preferred conditions can be combined arbitrarily to obtain various preferred embodiments of the present invention.

[0174] The reagents and raw materials used in this invention are all commercially available.

[0175] The positive and progressive effects of this invention are as follows:

[0176] (1) In this invention, the Sm2O3 is fully reduced by holding the temperature at the reduction treatment temperature and at the same time protected by an inert atmosphere (e.g., Ar). The diffusion treatment is carried out after heating, which helps to suppress the excessive volatilization of samarium and facilitates the complete diffusion reaction.

[0177] (2) In this invention, large-particle porous iron powder can be used in combination with fine-particle samarium oxide raw material. During the reduction and diffusion process, after thorough mixing, a material accumulation state is formed in which samarium oxide powder coats the porous iron powder. During the reduction and diffusion process, metallic samarium diffuses fully into the interior of the iron powder through the pores of the porous iron powder, forming Sm2Fe. 17 The alloy causes porous iron powder undergoing a diffusion reaction to spontaneously break down into small particles, Sm2Fe. 17 The alloy is formed, while the unreacted iron powder retains its original large particle shape, which makes it possible to remove excess iron powder in subsequent airflow separation.

[0178] (3) The present invention can use an inert gas jet mill to further crush and sort the coarse crushed product after reduction and diffusion, so that the remaining large iron powder particles that have not undergone reduction and diffusion reaction are separated from the product, and a product with very few iron impurities is obtained, thus avoiding the appearance of α-Fe soft magnetic phase in the final magnet and ensuring that the magnetic powder has high coercivity.

[0179] (4) The present invention can perform hydrogen crushing treatment on the reduction diffusion products after the first air jet milling, so that the larger particles Sm2Fe with a particle size of 4-25μm in the products are reduced. 17 The product further absorbs hydrogen and breaks down into fine Sm2Fe particles of 0.2-4 μm. 17 Alloy powder. Fine alloy powder is beneficial for improving the efficiency and degree of subsequent nitriding, while also possessing high coercivity.

[0180] (5) In this invention, the reduction diffusion products can be nitrided first to reduce the Sm2Fe in the mixed products. 17 Nitriding to form Sm2Fe 17 The N3 compound is then subjected to water washing to remove impurities, avoiding the Sm2Fe contamination that occurs in the traditional method of washing first and then nitriding. 17 Water washing corrosion and oxidation of the alloy, followed by nitriding to form Sm2Fe 17N3 compounds have high room temperature stability, are not easily oxidized or corroded, and facilitate thorough water washing to remove impurities from the mixed products. The final product has low Ca and O content and high magnetic properties. Attached Figure Description

[0181] Figure 1 The final samarium iron nitrogen product (Sm2Fe) in Example 1 17 SEM image of N3).

[0182] Figure 2 This is a particle size distribution diagram of the mixed product after reduction and diffusion in Example 1.

[0183] Figure 3 The final samarium iron nitrogen product (Sm2Fe) in Example 1 17 Particle size distribution diagram of N3.

[0184] Figure 4 This is a SEM image of the spherical iron powder (5μm, D50) in Example 8. Detailed Implementation

[0185] The present invention is further illustrated below by way of embodiments, but the invention is not limited to the scope of the embodiments described herein. Experimental methods in the following embodiments that do not specify specific conditions were performed according to conventional methods and conditions, or as selected according to the product instructions.

[0186] Example 1

[0187] The preparation process in this embodiment is as follows: batching - reduction diffusion - coarse crushing of product - product airflow separation - hydrogen crushing - nitriding - impurity washing - product drying - airflow dispersion and classification - finished magnetic powder.

[0188] The specific steps are as follows:

[0189] (1) Porous iron powder with a particle size of 115 μm (D50) was used as the raw material for the reduction-diffusion reaction. The porosity of the porous iron powder or foamed iron powder was 15%. Porous iron powder has high porosity and high reactivity, which can make the reaction proceed fully and quickly, and the reaction may be easily broken. Porosity refers to the percentage of pore volume in a block material to the total volume of the material in its natural state (generally referring to the state without external force).

[0190] (2) Samarium oxide powder is used as raw material with a particle size of 0.5 μm (D50).

[0191] (3) Ingredients: The material ratio is as follows: Sm2O3 + 17Fe + 3Ca = Sm2Fe 17The reaction equation for +3CaO was determined. To ensure the full reduction of samarium oxide, the amount of metallic Ca was prepared at 1.15 times the theoretical amount determined by the equation (15% excess). Meanwhile, considering the volatilization of metallic Sm during the reduction diffusion reaction at high temperature, the amount of Sm2O3 was prepared at 1.05 times the theoretical amount determined by the above equation (5% excess). After preparation, the raw materials were placed in a mixer for thorough mixing.

[0192] (4) Reduction diffusion:

[0193] Reduction treatment: The thoroughly mixed raw materials are placed in a vacuum heat treatment furnace and heated. During the temperature increase from room temperature to the reduction treatment temperature, the vacuum degree in the furnace is maintained at <0.1 Pa. After the material is heated to the reduction temperature, high-purity argon gas is introduced into the furnace at a pressure of 492 mbar. The material is then held at 930℃ for 2 hours for reduction treatment, which melts the metallic calcium and reduces Sm2O3 to metallic samarium.

[0194] Diffusion treatment: After reduction treatment, the material is heated to 1155℃ and held for 4 hours for diffusion treatment. The diffusion treatment atmosphere is argon gas at a pressure of 845 mbar, which allows metallic Sm to diffuse into the porous iron powder and form Sm2Fe. 17 The alloy spontaneously breaks down into alloy powder of 2-25 μm (see particle size distribution diagram). Figure 2 ).

[0195] (5) Coarse crushing: The product after reduction and diffusion is mechanically coarsely crushed to make the product particle size <2mm. Coarse crushing can be done by jaw crusher or disc mill crusher.

[0196] (6) Air jet milling: The coarsely crushed powder is further crushed and sorted using an air jet mill to break and disperse the agglomerated product after the reaction, and to obtain a mixed product with a particle size of 0.5-25μm. The large iron powder particles (>25μm) that have not been fully reacted are separated from the product to obtain a mixed product without iron powder.

[0197] (7) Hydrogen Crushing: The powder after air jet milling is placed in a vacuum hydrogen crushing furnace for hydrogen crushing. After evacuating the furnace body, 800 mbar (absolute pressure) H2 gas is introduced, and the temperature is raised to 150℃ to absorb hydrogen for 5 hours. Then, the furnace is evacuated at 300℃ (vacuum degree <0.1 Pa) to remove hydrogen, so that the Sm2Fe in the mixed product is removed. 17 The alloy undergoes hydrogen absorption and breakage, causing the remaining metallic Ca layer adhering to the product surface to transform into CaH2, which then pulverizes and peels off.

[0198] (8) Nitriding: The hydrogen-crushed product is nitrided at 500℃ and 1.0MPa. The nitriding medium is N2, and the nitriding time is 10h, so that the Sm2Fe in the mixed product is reduced. 17Alloy nitriding forms Sm2Fe 17 N3 compounds.

[0199] (9) Washing: The nitrided product is washed with water to remove impurities such as CaO, Ca, and CaH2 from the mixed product. A small amount of weak acid such as acetic acid can also be added during the washing process to keep the pH of the washing solution >= 6. After washing, alcohol is used to dehydrate the washed product.

[0200] (10) The product after thorough washing and dehydration is vacuum dried.

[0201] (11) The vacuum-dried powder is subjected to nitrogen or argon gas flow milling to break up and disperse the dried and agglomerated product, resulting in Sm2Fe with a particle size (D50) of approximately 1.7 μm. 17 N3 magnetic powder (SEM image see [link]) Figure 1 See the particle size distribution diagram. Figure 3 During the grinding process, 0.4% of the organic antioxidant N,N-di-sec-butyl-p-phenylenediamine can be added (the percentage refers to the organic antioxidant in Sm2Fe). 17 The mass percentage of N3 magnetic powder, for example, 100g Sm2Fe 17 0.4g of organic antioxidant (0.4% of N3 magnetic powder) and 0.55% of dispersant 120# solvent oil were added (the percentage refers to the dispersant concentration in Sm2Fe). 17 The magnetic powder is subjected to antioxidant and dispersion treatment (by mass percentage of N3 magnetic powder), and the total amount of additives (organic antioxidants and dispersants) added is 0.95%.

[0202] Examples 2-9, Comparative Examples 1-4

[0203] The formulations and processes for Examples 2-9 and Comparative Examples 1-4 are as shown in Table 1 below, and the other conditions are the same as in Example 1.

[0204] Table 1

[0205]

[0206]

[0207] Note: Porous iron powder refers to iron powder with a certain porosity, which can be purchased from Shijiaweier Technology Co., Ltd.

[0208] Reduced iron powder refers to loose iron powder (with a density of 6.5 g / cm³) produced by reducing iron(III) oxide (Fe3O4) under high heat in a stream of hydrogen or carbon monoxide. 3 It can be purchased from Guangzhou Metal Metallurgy Co., Ltd.

[0209] Spherical iron powder refers to iron powder with a dense spherical shape (its density is 7.8 g / cm³).3 The spherical iron powder can be purchased from China Metallurgical Xindun Company (see Example 8 for spherical iron powder). Figure 4 ).

[0210] Example 1

[0211] The Sm2Fe obtained from Examples 1-9 and Comparative Examples 1-4 was used. 17 N3 magnetic powder was tested for magnetic properties, particle size, samarium content, oxygen content, α-Fe content, and calcium content. The specific testing methods are as follows:

[0212] 1. The magnetic properties were measured using a vibrating sample magnetometer (VSM), model LakeShore 7411;

[0213] 2. Particle size was tested using a laser particle size analyzer, model Malvern Mastersizer2000.

[0214] 3. The samarium content was detected using an X-ray fluorescence spectrometer, specifically a Panalytical Axiosmax instrument.

[0215] 4. Oxygen content was measured using an oxygen-nitrogen analyzer, model Horiba EMGA-620W;

[0216] 5. The α-Fe content was detected using an X-ray diffractometer, specifically a Bruker D8DISCOVER.

[0217] 6. Calcium content was measured using an inductively coupled plasma optical emission spectrometer (ICP-OES), model SPECTROBLUE FMX36.

[0218] The test results are shown in Tables 2 and 3 below.

[0219] Table 2

[0220]

[0221]

[0222] Note: The wt% in Table 2 refers to the content of Sm2Fe 17 Weight percentage of N3 magnetic powder.

[0223] Table 3

[0224] serial number Samarium addition amount / wt% Samarium remaining amount / wt% Samarium volatility / wt% Example 1 25.7 24.5 1.2 Example 2 25.2 24.2 1.0 Example 3 25.4 24.5 0.9 Example 4 26.2 24.9 1.3 Example 5 26.5 25 1.5 Example 6 26.8 25.3 1.5 Example 7 26 24.9 1.1 Example 8 26.3 25.1 1.2 Example 9 25.9 24.8 1.1 Comparative Example 1 27.5 23.3 4.2 Comparative Example 2 28 23.1 4.9 Comparative Example 3 29 28.3 0.7 Comparative Example 4 30.5 25.1 5.4 Comparative Example 5 25.7 23.7 2.0 Comparative Example 6 25.7 23.2 2.5

[0225] Note: The wt% in Table 3 refers to the content of Sm2Fe 17 Weight percentage of N3 magnetic powder.

[0226] According to Tables 2 and 3:

[0227] Examples 1-9: Sm2Fe prepared 17 N3 magnetic powder exhibits excellent properties, with Hcj ≥ 12.3 kOe, α-Fe content ≤ 0.64 wt%, oxygen content ≤ 1.32 wt%, and calcium content ≤ 0.05 wt%. Furthermore, compared to conventionally morphological (dense spherical) fine-grained iron powder (0.5-40 μm), porous iron powder with a porosity of 10%-40% can further reduce Sm2Fe. 17 α-Fe content and oxygen content in N3 magnetic powder;

[0228] Comparative Example 1: Compared with Examples 1-9, reduction and diffusion are in the same temperature range, the atmospheric pressure is low, the reduction temperature is too high and the diffusion temperature is too low, more samarium metal volatilizes and less enters the iron powder, the magnetic properties are poor, and the α-Fe content and oxygen content are high.

[0229] Comparative Example 2: Compared with Examples 1-9, samarium volatilization is high, resulting in insufficient samarium for diffusion. Samarium cannot penetrate the entire iron powder to form a complete Sm2Fe. 17 Therefore, the spontaneous crushing effect of iron powder is poor, the powder particle size is large, the α-Fe residue is high, and the magnetic properties are low.

[0230] Comparative Example 3: Compared with Examples 1-9, the reduction and diffusion temperature was too low, the reduction and diffusion were incomplete, and the reduction and diffusion of samarium were insufficient. Although less samarium volatilized, it led to a high α-Fe content. At the same time, the metallic samarium remaining on the surface of the iron powder was oxidized in subsequent processes, resulting in high oxygen content and poor performance.

[0231] Comparative Example 4: Compared with Examples 1-9, the reduction diffusion temperature was too high, the atmosphere pressure was too low, more samarium volatilized, the diffusion reaction lacked sufficient samarium, the diffusion reaction was incomplete, and samarium could not penetrate the entire iron powder to form a complete Sm2Fe. 17 Therefore, the spontaneous crushing effect of iron powder is poor, the powder particle size is large, the α-Fe residue is high, and the magnetic properties are low.

[0232] Comparative Example 5

[0233] The heat preservation time in step (4) of Example 1 was adjusted to 6 hours, and the remaining steps were the same as in Example 1.

[0234] In Comparative Example 5, the heat treatment time during the reduction process was too long, resulting in excessive samarium volatilization and insufficient samarium required for diffusion. Consequently, samarium could not penetrate the entire iron powder to form a complete Sm2Fe. 17 Therefore, the spontaneous crushing effect of iron powder is poor, the powder particle size is large, the α-Fe residue is high, and the magnetic properties are low.

[0235] Comparative Example 6

[0236] The heat preservation time in the diffusion treatment in step (4) of Example 1 was adjusted to 12 hours, and the remaining steps were the same as in Example 1.

[0237] In Comparative Example 6, the excessively long holding time during the diffusion process led to Sm2Fe 17 The alloy powders agglomerated and grew again, increasing the Sm2Fe content in the mixture. 17 The particle size is unfavorable for subsequent crushing and iron removal, while Sm2Fe 17 Samarium in the product volatilizes during prolonged heat preservation, producing secondary α-Fe precipitation, which reduces magnetic properties.

Claims

1. A method for manufacturing a samarium-iron alloy, characterized in that, It includes the following steps: (1) Mixture A is subjected to a first heat treatment in a protective atmosphere A to obtain mixture B; In the protective atmosphere A, the gas pressure P1 is 400-680 mbar; The temperature T1 of the first heat preservation treatment is 800-950℃; The duration t1 of the first heat preservation treatment is 1-5 hours; The mixture A contains Sm2O3, Fe and Ca; The gas pressure P1 in the protective atmosphere A, the temperature T1 of the first heat preservation treatment, and the time t1 of the first heat preservation treatment satisfy the following condition: P1 / mbar=α1*T1 / ℃+β1*t1 / h, where: α1 is 0.1-1.0, and β1 is 50-70; (2) The mixture B is subjected to a second heat treatment in a protective atmosphere B to obtain the samarium-iron alloy; In the protective atmosphere B, the gas pressure P2 is 750-950 mbar; the gas pressure P2 in the protective atmosphere B minus the gas pressure P1 in the protective atmosphere A is greater than 200 mbar. The temperature T2 of the second heat preservation treatment is 1050-1180℃; The second heat preservation treatment time t2 is 2-10 hours; The gas pressure P2 in the protective atmosphere B, the temperature T2 of the second heat preservation treatment, and the time t2 of the second heat preservation treatment satisfy the following condition: P2 / mbar=α2*T2 / ℃+β2*t2 / h, where: α2 is 0.1-1.0, and β2 is 1-20.

2. The method for manufacturing samarium-iron alloy as described in claim 1, characterized in that, The method for manufacturing the samarium-iron alloy satisfies one or more of the following conditions: ①In step (1), the protective atmosphere A is an argon atmosphere; ② In step (1), the gas pressure P1 in the protective atmosphere A is 440 mbar, 480 mbar, 492 mbar, 500 mbar, 540 mbar or 640 mbar; ③ In step (1), the temperature T1 of the first heat preservation treatment is 850-950℃; ④ In step (1), the time t1 of the first heat preservation treatment is 2-5 hours; ⑤ In step (1), α1 is 0.1-0.5; ⑥ In step (1), the Fe is in the form of reduced iron powder, spherical iron powder or porous iron powder; ⑦ The particle size of the Sm2O3 is 0.1-10 μm; In step (2), the protective atmosphere B is an argon atmosphere; ⑨ In step (2), the gas pressure P2 in the protective atmosphere B is 755 mbar, 844 mbar, 845 mbar, 846 mbar, 850 mbar, 851 mbar, 852 mbar, 885 mbar or 926 mbar; ⑩ The gas pressure P2 in the protective atmosphere B and the gas pressure P1 in the protective atmosphere A are 201-450 mbar; ⑪ In step (2), the temperature T2 of the second heat preservation treatment is 1100-1180℃; ⑫ In step (2), the time t2 of the second heat preservation treatment is 4-10 hours; ⑬ In step (2), α2 is 0.6-0.8; and, ⑭ In step (2), the samarium-iron alloy is further subjected to coarse crushing, air jet milling and hydrogen crushing post-treatment.

3. The method for manufacturing samarium-iron alloy as described in claim 2, characterized in that, The method for manufacturing the samarium-iron alloy satisfies one or more of the following conditions: ① In step (1), the temperature T1 of the first heat preservation treatment is 850℃, 900℃, 930℃ or 950℃; ② In step (1), the time t1 of the first heat preservation treatment is 2 hours, 3 hours or 5 hours; ③ In step (1), α1 is 0.4; ④ In step (1), β1 is 55-65; ⑤ The gas pressure P1 in the protective atmosphere A, the temperature T1 of the first heat preservation treatment, and the time t1 of the first heat preservation treatment satisfy the following conditions: P1 / mbar = 0.4 * T1 / ℃ + 60 * t1 / h; ⑥ The particle size of the reduced iron powder is 0.5-40 μm; ⑦ The particle size of the spherical iron powder is 0.5-40 μm; The porous iron powder has a particle size of 50-150 μm; ⑨ The porosity of the porous iron powder is 10%-40%; ⑩ The particle size of the Sm2O3 is 0.5μm, 2.5μm, 4μm, 5μm or 6μm; ⑪ The gas pressure P2 in the protective atmosphere B and the gas pressure P1 in the protective atmosphere A are 210 mbar, 255 mbar, 286 mbar, 304 mbar, 311 mbar, 345 mbar, 353 mbar, 372 mbar or 406 mbar. ⑫ In step (2), the temperature T2 of the second heat preservation treatment is 1100℃, 1120℃, 1130℃, 1150℃, 1160℃ or 1180℃; ⑬ In step (2), the time t2 of the second heat preservation treatment is 4 hours, 6 hours, 8 hours or 10 hours; ⑭ In step (2), α2 is 0.7; ⑮ In step (2), β2 is 5-15; ⑯ The gas pressure P2 in the protective atmosphere B, the temperature T2 of the second heat preservation treatment, and the time t2 of the second heat preservation treatment satisfy the following conditions: P2 / mbar = 0.7 * T2 / ℃ + 10 * t2 / h; and, ⑰ The hydrogen crushing is carried out according to the following process: the samarium-iron alloy is subjected to hydrogen absorption at 150-250℃ for 2-6 hours, and then dehydrogenated by vacuuming at 250-350℃.

4. The method for manufacturing samarium-iron alloy as described in claim 3, characterized in that, The method for manufacturing the samarium-iron alloy satisfies one or more of the following conditions: ① The temperature T1 of the first heat preservation treatment is 900-950℃, and the time t1 of the first heat preservation treatment is 1-3 hours; ② In step (1), β1 is 60; ③ The particle size of the reduced iron powder is 15μm, 25μm or 40μm; ④ The particle size of the spherical iron powder is 0.5μm, 5μm or 10μm; ⑤ The porous iron powder has a particle size of 80μm, 115μm or 150μm; ⑥ The porosity of the porous iron powder is 15%, 25%, or 35%; ⑦ The temperature T2 of the second heat preservation treatment is 1050-1160℃, and the time t2 of the second heat preservation treatment is 2-6 hours; In step (2), β2 is 10; ⑨ The hydrogen crushing is carried out in an atmosphere of 500-900 mbar H2 gas; ⑩ The temperature for hydrogen absorption is 150-240℃; ⑪ The hydrogen absorption time is 4-6 hours; and, ⑫ The dehydrogenation temperature is 280-350℃.

5. The method for manufacturing samarium-iron alloy as described in claim 4, characterized in that, The method for manufacturing the samarium-iron alloy satisfies one or more of the following conditions: ①The temperature for hydrogen absorption is 150℃, 200℃, 220℃, 225℃, 230℃ or 240℃; ②The hydrogen absorption time is 5 hours; and, ③ The dehydrogenation temperature is 280℃, 300℃, 320℃ or 350℃.

6. A samarium-iron alloy, characterized in that, It is prepared by the manufacturing method of samarium iron alloy as described in any one of claims 1-5.

7. The samarium-iron alloy as described in claim 6, characterized in that, The content of Sm is 23-27 wt%, the content of α-Fe is ≤0.64 wt%, the content of oxygen is ≤1.32 wt%, the content of calcium is ≤0.1 wt%, and the balance is Fe.

8. A method for manufacturing a samarium iron nitrogen permanent magnet material, characterized in that, It includes the following steps: nitriding the samarium-iron alloy as described in claim 6 or 7.

9. The method for manufacturing samarium iron nitrogen permanent magnet material as described in claim 8, characterized in that, The manufacturing method of the samarium iron nitrogen permanent magnet material satisfies one or more of the following conditions: ① The nitriding temperature is 450-550℃; ② The nitriding pressure is 0.09 MPa-1.5 MPa; ③ The nitriding medium is N2, NH3, a mixture of N2 and H2, a mixture of NH3 and H2, or a mixture of N2, NH3 and H2. ④ Under conditions of 0.09-1.5 MPa, the nitriding time is 4-20 h; and, ⑤ The nitriding process also includes a water washing step.

10. The method for manufacturing samarium iron nitrogen permanent magnet material as described in claim 9, characterized in that, The manufacturing method of the samarium iron nitrogen permanent magnet material satisfies condition ① and / or condition ② below: ①The nitriding temperature is 450℃, 480℃, 500℃, 520℃ or 550℃; ② The nitriding pressure is 0.09MPa, 0.2MPa, 0.5MPa, 0.8MPa, 0.9MPa, 1.0MPa, 1.2MPa or 1.5MPa.

11. A samarium iron nitrogen permanent magnet material, characterized in that, It is prepared by the manufacturing method of samarium iron nitrogen permanent magnet material as described in any one of claims 8-10.

12. The samarium iron nitrogen permanent magnet material as described in claim 11, characterized in that, The content of Sm is 23-27 wt%, the content of α-Fe is ≤0.64 wt%, the content of oxygen is ≤1.32 wt%, the content of calcium is ≤0.1 wt%, and the balance is Fe and nitrogen.

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