A samarium-based rare earth permanent magnet material and its preparation method and application

Abstract

The present invention relates to a samarium-based rare earth permanent magnet material and a preparation method and application thereof. The samarium-based rare earth permanent magnet material Sm2Fe α Cu β V γ Mo δ N ε 11.5≤α≤17.5, 0.1≤β≤0.4, 1.0≤γ≤1.8, 0≤δ≤1.0, 2.9≤ε≤4.0. The samarium-based rare earth permanent magnet material provided by the present invention is doped with vanadium, copper, and molybdenum elements and regulated within an appropriate atomic ratio range to promote a good balance between remanence and coercivity, resulting in excellent comprehensive magnetic properties. The preparation method provided by the present invention is simple to operate and low in cost, and is suitable for use in the fields of micro motors, magnetic sensors, or audio equipment.

Description

Technical Field

[0001] The present invention belongs to the technical field of magnetic materials, and relates to a permanent magnetic material and a preparation method and application thereof, and specifically relates to a samarium-based rare earth permanent magnetic material and a preparation method and application thereof. Background Art

[0002] Neodymium iron boron rare earth permanent magnet materials are widely used in automobiles, home appliances and industrial equipment due to their high remanence, high coercivity and high magnetic energy product. 17 N x Samarium-based rare earth permanent magnet materials represented by compounds have higher Curie temperature, anisotropy field and similar saturation magnetization than NdFeB permanent magnet materials, and are considered to have the potential to become a new generation of permanent magnet materials. 17 N x When the temperature exceeds 550°C, the compound will undergo irreversible decomposition and the magnetic properties will be greatly reduced.

[0003] CN 105355354A discloses an anisotropic samarium-iron-nitrogen-based rare earth permanent magnet powder and its preparation method. The powder provides a magnetic 2:17 main phase surrounded by a low-melting-point phase composed of R and M2 elements. This allows the alloy to accommodate excess rare earth elements without forming SmFe2 and SmFe3 phases. This helps eliminate defects in the 2:17 main phase grains, reducing reverse domain nucleation points and decoupling effects. However, the powder's oxidation resistance and magnetic properties still need to be further improved.

[0004] CN 108994311A discloses a method for preparing anisotropic, high-performance samarium-iron-nitrogen (SmFeN) permanent magnet alloy powder using a solid salt spray granulation and reduction-diffusion method. The method comprises the following steps: batching and mixing; spray granulation; mixing the microspheres obtained in the previous step with calcium particles, subjecting them to a reduction-diffusion reaction to obtain a SmFe alloy; and nitriding treatment to obtain the product. The SmFeN permanent magnet alloy powder produced by spray granulation has a high coercivity. However, the magnetic powder is difficult to clean with water after nitriding, significantly impacting subsequent granulation. Furthermore, the spray granulation process utilizes equipment susceptible to chloride corrosion.

[0005] CN 111403165A discloses a method for preparing a samarium iron nitrogen / nano-iron composite bonded permanent magnet. This method utilizes chemical vapor deposition to coat the surface of samarium iron nitrogen powder with a nano-Fe film, followed by an antioxidant coating. After granulation, the composite bonded magnet is produced through injection molding or calendering, compression molding, or extrusion. While this bonded magnet exhibits high oxidation resistance, the preparation process is relatively complex, and the resulting bonded magnet exhibits low overall magnetic properties.

[0006] In view of the shortcomings of the existing technology, there is an urgent need to provide a rare earth permanent magnet material with excellent magnetic properties and low cost. Summary of the Invention

[0007] The purpose of the present invention is to provide a samarium-based rare earth permanent magnet material and its preparation method and application. By introducing vanadium, copper and molybdenum elements, the intrinsic properties and microstructure of the samarium-based rare earth permanent magnet material can be adjusted, thereby improving the comprehensive magnetic properties of the samarium-based rare earth permanent magnet material. The preparation process is simple and low-cost.

[0008] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0009] In a first aspect, the present invention provides a samarium-based rare earth permanent magnet material, wherein the composition of the samarium-based rare earth permanent magnet material expressed in atomic ratio is: Sm2Fe α Cu β V γ Mo δ N ε , among which, 11.5≤α≤17.5, 0.1≤β≤0.4, 1.0≤γ≤1.8, 0≤δ≤1.0, 2.9≤ε≤4.0.

[0010] The composition of the samarium-based rare earth permanent magnet material is Sm2Fe α Cu β V γ Mo δ N ε 11.5≤α≤17.5, for example, it can be 11.5, 12.5, 13.5, 14.5, 15.5, 16.5 or 17.5, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0011] The composition of the samarium-based rare earth permanent magnet material is Sm2Fe α Cu β V γ Mo δ N ε 0.1≤β≤0.4, for example, it can be 0.1, 0.15, 0.2, 0.25, 0.3, 0.35 or 0.4, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0012] The composition of the samarium-based rare earth permanent magnet material is Sm2Fe α Cu β V γ Mo δ N ε Here, 1.0≤γ≤1.8, for example, it can be 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7 or 1.8, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0013] The composition of the samarium-based rare earth permanent magnet material is Sm2Feα Cu β V γ Mo δ N ε 0≤δ≤1.0, for example, it can be 0, 0.2, 0.4, 0.6, 0.8 or 1.0, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0014] The composition of the samarium-based rare earth permanent magnet material is Sm2Fe α Cu β V γ Mo δ N ε 2.9≤ε≤4.0, for example, it can be 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9 or 4.0, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0015] The samarium-based rare earth permanent magnet material provided by the present invention is based on a samarium iron nitrogen rare earth permanent magnet material. By doping with vanadium, copper and molybdenum elements, the microstructure of the material, such as grain boundaries, grain size or lattice defects, is changed. By regulating the appropriate atomic ratio range, the samarium-based rare earth permanent magnet material has excellent comprehensive magnetic properties and oxidation resistance, and can meet the performance requirements of a rare earth permanent magnet material.

[0016] In a second aspect, the present invention provides a method for preparing the samarium-based rare earth permanent magnet material as described in the first aspect, the preparation method comprising the following steps:

[0017] (1) mixing metal samarium powder, iron powder, copper powder, vanadium powder and molybdenum powder according to the formula, and sequentially melting and rapidly solidifying ingots to obtain alloy sheets;

[0018] (2) The alloy flakes obtained in step (1) are crushed, nitrided, and ball-milled in sequence to obtain alloy powder;

[0019] (3) The alloy powder obtained in step (2) is sequentially subjected to phosphating and heat treatment, and then cooled to obtain the samarium-based rare earth permanent magnet material.

[0020] The preparation method of the samarium-based rare earth permanent magnet material provided by the present invention can effectively improve the antioxidant effect of the samarium-based rare earth permanent magnet material by regulating the nitriding process parameters, controlling the ball milling particle size, and adopting phosphating and heat treatment processes, promote the balance between remanence and coercive force, and thus obtain excellent comprehensive magnetic properties.

[0021] Preferably, the smelting temperature in step (1) is 1400-1600°C, for example, it can be 1400°C, 1450°C, 1500°C, 1550°C or 1600°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0022] Preferably, the smelting time in step (1) is 50-70 min, for example, 50 min, 55 min, 60 min, 65 min or 70 min, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0023] Preferably, the smelting in step (1) is carried out in an argon atmosphere.

[0024] Preferably, the pulverizing step in step (2) is as follows: the alloy flakes obtained in step (1) are subjected to mechanical crushing and air flow grinding in sequence to obtain powder particles.

[0025] Preferably, the average particle size of the powder particles is 50-100 μm, for example, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm or 100 μm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0026] Preferably, the jet milling is carried out in an argon atmosphere.

[0027] Preferably, the nitriding in step (2) includes a first heat treatment and a second heat treatment performed sequentially.

[0028] Preferably, the first heat treatment is: heating to 500-550° C. and keeping the temperature for 4-10 hours in an ammonia atmosphere.

[0029] In the first heat treatment, the temperature is raised to 500-550°C, for example, 500°C, 510°C, 520°C, 530°C, 540°C or 550°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0030] The first heat treatment is kept warm for 4-10 hours, for example, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours or 10 hours, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable.

[0031] The first heat treatment of the present invention can nitride the powder particles obtained by crushing. The composition of the samarium-based rare earth permanent magnet material is Sm2Fe α Cu β V γ Mo δ N εThe value of ε is significantly affected by the heating temperature and holding time. As the heating temperature and holding time increase, the value of ε increases accordingly. When the heating temperature and holding time are controlled within a reasonable range, the value of ε can be maintained within the range of 2.9-4.0, and the samarium-based rare earth permanent magnet material has good magnetic properties.

[0032] Preferably, the second heat treatment is: cooling to 400-450° C. and keeping the temperature for 50-70 minutes under an argon atmosphere.

[0033] In the second heat treatment, the temperature is lowered to 400-450°C, for example, 400°C, 410°C, 420°C, 430°C, 440°C or 450°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0034] The second heat treatment is kept warm for 50-70 minutes, for example, 50 minutes, 55 minutes, 60 minutes, 65 minutes or 70 minutes, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable.

[0035] Preferably, the powder particles are sequentially subjected to the first heat treatment and the second heat treatment and then cooled to room temperature under an argon atmosphere.

[0036] Preferably, the ball milling in step (2) is carried out in an argon atmosphere.

[0037] Preferably, the average particle size of the alloy powder in step (2) is 2-4 μm, for example, 2 μm, 2.5 μm, 3 μm, 3.5 μm or 4 μm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0038] The ball milling method of the present invention controls the average particle size of the alloy powder to 2-4 μm, resulting in a samarium-based rare earth permanent magnet material with superior overall magnetic properties. When the particle size is less than 2 μm, the material's coercivity increases, but its remanence decreases significantly. When the particle size is greater than 4 μm, the remanence increases slightly, but the coercivity decreases significantly. Therefore, controlling the alloy powder particle size within a reasonable range can achieve a balance between remanence and coercivity, thereby achieving better overall magnetic properties.

[0039] Preferably, the phosphating step in step (3) is: mixing phosphoric acid, a solvent and the alloy powder obtained in step (2), and heating until the solvent evaporates to obtain the phosphated alloy powder.

[0040] The purpose of the phosphating treatment in the present invention is to form a phosphating film on the surface of the alloy powder, thereby effectively improving the anti-oxidation effect of the alloy powder.

[0041] Preferably, the mass of the phosphoric acid is 2.5-3.5 wt% of the mass of the alloy powder in step (2), for example, it can be 2.5 wt%, 2.8 wt%, 3.0 wt%, 3.2 wt% or 3.5 wt%, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0042] Preferably, the mass ratio of the solvent to the alloy powder in step (2) is (0.8-1.2):1, for example, it can be 0.8:1, 0.9:1, 1:1, 1.1:1 or 1.2:1, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0043] Preferably, the solvent comprises ethanol.

[0044] Preferably, the terminal temperature of the heating is 78-82°C, for example, 78°C, 79°C, 80°C, 81°C or 82°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0045] Preferably, the phosphating in step (3) is carried out in a nitrogen atmosphere.

[0046] Preferably, the terminal temperature of the heat treatment in step (3) is 140-160°C, for example, it can be 140°C, 145°C, 150°C, 155°C or 160°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0047] Preferably, the holding time of the heat treatment in step (3) is 3.5-4.5h, for example, it can be 3.5h, 3.8h, 4h, 4.2h or 4.5h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0048] Preferably, the heat treatment in step (3) is carried out in an oxygen-containing atmosphere, and the protective gas of the oxygen-containing atmosphere is nitrogen.

[0049] Preferably, the concentration of oxygen in the oxygen-containing atmosphere is 50-100 ppm, for example, 50 ppm, 60 ppm, 70 ppm, 80 ppm, 90 ppm or 100 ppm, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0050] The heat treatment described in the present invention can solidify the phosphating film formed on the surface of the phosphating alloy powder; in addition, by setting a trace oxygen environment, the small area on the surface of the phosphating alloy powder that is not completely covered by the phosphating film is slightly oxidized to form a thinner oxide film, further improving the anti-oxidation effect of the material.

[0051] As a preferred technical solution of the preparation method described in the second aspect of the present invention, the preparation method comprises the following steps:

[0052] (1) mixing metal samarium powder, iron powder, copper powder, vanadium powder and molybdenum powder according to the formula, smelting at 1400-1600°C for 50-70 minutes in an argon atmosphere, and rapidly solidifying the mixture into an ingot to obtain an alloy sheet;

[0053] (2) The alloy flakes obtained in step (1) were subjected to mechanical crushing, air flow milling, nitriding, and ball milling in an argon atmosphere to obtain an alloy powder with an average particle size of 2-4 μm;

[0054] The average particle size of the powder particles obtained by the jet mill is 50-100 μm; the nitriding includes a first heat treatment and a second heat treatment performed in sequence; the first heat treatment is: in an ammonia atmosphere, the temperature is raised to 500-550° C. and kept at this temperature for 4-10 hours; the second heat treatment is: in an argon atmosphere, the temperature is lowered to 400-450° C. and kept at this temperature for 50-70 minutes;

[0055] (3) The alloy powder obtained in step (2) is sequentially subjected to phosphating, heat treatment in an oxygen-containing atmosphere with an oxygen concentration of 50-100 ppm to a temperature of 140-160° C., heat preservation for 3.5-4.5 hours, and cooling to obtain the samarium-based rare earth permanent magnet material;

[0056] The phosphating step comprises: mixing phosphoric acid, a solvent and the alloy powder obtained in step (2) in a nitrogen atmosphere, and heating until the solvent evaporates to obtain a phosphated alloy powder; the mass of the phosphoric acid is 2.5-3.5wt% of the mass of the alloy powder in step (2); and the mass ratio of the solvent to the alloy powder in step (2) is (0.8-1.2):1.

[0057] In a third aspect, the present invention provides an application of the samarium-based rare earth permanent magnet material as described in the first aspect, wherein the samarium-based rare earth permanent magnet material is used in the fields of micro motors, magnetic sensors or audio equipment.

[0058] Compared with the prior art, the present invention has the following beneficial effects:

[0059] The samarium-based rare earth permanent magnet material provided by the present invention has excellent comprehensive magnetic properties by doping vanadium, copper and molybdenum elements and regulating the appropriate atomic ratio range. The remanence can reach 7180Gs, the coercive force is 10350Oe, and the magnetic energy product can reach 12.3MGOe.

[0060] The phosphating and heat treatment processes can effectively improve the antioxidant effect of samarium-based rare earth permanent magnet materials; by regulating the heating temperature and time of the nitriding process and controlling the ball milling particle size, a good balance between remanence and coercive force is achieved, thereby obtaining excellent magnetic properties. The preparation method provided by the present invention is simple to operate and has low cost, and is suitable for the fields of micro motors, magnetic sensors or audio equipment. DETAILED DESCRIPTION

[0061] The technical solution of the present invention is further described below by way of specific embodiments. It should be understood by those skilled in the art that the embodiments are merely to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0062] Example 1

[0063] This embodiment provides a samarium-based rare earth permanent magnet material, the composition of the samarium-based rare earth permanent magnet material expressed in atomic ratio is: Sm2Fe α Cu β V γ Mo δ N ε , where α=14, β=0.3, γ=1.5, δ=0.5, ε=3.75.

[0064] The samarium-based rare earth permanent magnet material is obtained by the following preparation method, which comprises the following steps:

[0065] (1) mixing metal samarium powder, iron powder, copper powder, vanadium powder and molybdenum powder according to the formula, melting at 1500°C for 60 minutes in an argon atmosphere and rapidly solidifying into an ingot to obtain an alloy sheet;

[0066] (2) The alloy flakes obtained in step (1) were subjected to mechanical crushing, air flow milling under argon protection, nitriding, and ball milling in an argon atmosphere to obtain an alloy powder with an average particle size of 3 μm;

[0067] The average particle size of the powder particles obtained by the jet mill is 80 μm. The nitriding includes a first heat treatment and a second heat treatment performed sequentially. The first heat treatment is: heating to 520° C. in an ammonia atmosphere and holding the temperature for 7 hours; the second heat treatment is: cooling to 420° C. in an argon atmosphere and holding the temperature for 60 minutes.

[0068] (3) The alloy powder obtained in step (2) is sequentially subjected to phosphating, heat treatment in an oxygen-containing atmosphere with an oxygen concentration of 70 ppm to 150° C., heat preservation for 4 hours, and cooling to obtain the samarium-based rare earth permanent magnet material;

[0069] The phosphating step comprises: mixing phosphoric acid, ethanol and the alloy powder obtained in step (2) in a nitrogen atmosphere, heating at 80° C. until the ethanol volatilizes, and obtaining the phosphated alloy powder; the mass of the phosphoric acid is 3 wt % of the mass of the alloy powder in step (2); the mass ratio of the ethanol to the alloy powder in step (2) is 1:1; and the protective gas of the oxygen-containing atmosphere is nitrogen.

[0070] Example 2

[0071] This embodiment provides a samarium-based rare earth permanent magnet material, the composition of the samarium-based rare earth permanent magnet material expressed in atomic ratio is: Sm2Fe α Cu β V γ Mo δ N ε , where α=14, β=0.3, γ=1.5, δ=0.5, ε=3.70.

[0072] The samarium-based rare earth permanent magnet material is obtained by the following preparation method, which comprises the following steps:

[0073] (1) Samarium powder, iron powder, copper powder, vanadium powder and molybdenum powder were mixed according to the formula, and the alloy sheets were obtained by melting at 1450°C for 65 minutes and then rapidly solidifying ingots in an argon atmosphere;

[0074] (2) The alloy flakes obtained in step (1) were subjected to mechanical crushing, air flow milling under argon protection, nitriding, and ball milling in an argon atmosphere to obtain an alloy powder with an average particle size of 3.5 μm;

[0075] The average particle size of the powder particles obtained by the jet mill is 65 μm. The nitriding includes a first heat treatment and a second heat treatment performed sequentially. The first heat treatment is: heating to 510° C. in an ammonia atmosphere and holding the temperature for 8.5 hours; the second heat treatment is: cooling to 410° C. in an argon atmosphere and holding the temperature for 65 minutes.

[0076] (3) The alloy powder obtained in step (2) was sequentially subjected to phosphating, heat treatment in an oxygen-containing atmosphere with an oxygen concentration of 60 ppm to 145° C., heat preservation for 4.2 hours, and cooling to obtain the samarium-based rare earth permanent magnet material;

[0077] The phosphating step comprises: mixing and heating phosphoric acid, ethanol and the alloy powder obtained in step (2) in a nitrogen atmosphere, heating at 79° C. until the ethanol volatilizes, and obtaining the phosphated alloy powder; the mass of the phosphoric acid is 3.2 wt % of the mass of the alloy powder in step (2); the mass ratio of the ethanol to the alloy powder in step (2) is 1.1:1; and the protective gas of the oxygen-containing atmosphere is nitrogen.

[0078] Example 3

[0079] This embodiment provides a samarium-based rare earth permanent magnet material, the composition of the samarium-based rare earth permanent magnet material expressed in atomic ratio is: Sm2Fe α Cu β V γ Mo δ N ε , where α=14, β=0.3, γ=1.5, δ=0.5, ε=3.80.

[0080] The samarium-based rare earth permanent magnet material is obtained by the following preparation method, which comprises the following steps:

[0081] (1) mixing metal samarium powder, iron powder, copper powder, vanadium powder and molybdenum powder according to the formula, melting at 1550°C for 55 minutes in an argon atmosphere and rapidly solidifying the ingot to obtain alloy sheets;

[0082] (2) The alloy flakes obtained in step (1) were mechanically crushed, pulverized by jet milling under argon protection, nitrided, and ball milled in an argon atmosphere to obtain an alloy powder with an average particle size of 2.5 μm;

[0083] The average particle size of the powder particles obtained by the jet mill is 90 μm. The nitriding includes a first heat treatment and a second heat treatment performed sequentially. The first heat treatment is: heating to 535° C. in an ammonia atmosphere and holding the temperature for 5.5 hours; the second heat treatment is: cooling to 435° C. in an argon atmosphere and holding the temperature for 55 minutes.

[0084] (3) The alloy powder obtained in step (2) is sequentially subjected to phosphating, heat treatment in an oxygen-containing atmosphere with an oxygen concentration of 85 ppm to 155° C., heat preservation for 3.8 hours, and cooling to obtain the samarium-based rare earth permanent magnet material;

[0085] The phosphating step comprises: mixing and heating phosphoric acid, ethanol and the alloy powder obtained in step (2) in a nitrogen atmosphere, heating at 81° C. until the ethanol volatilizes, and obtaining the phosphated alloy powder; the mass of the phosphoric acid is 2.8 wt % of the mass of the alloy powder in step (2); the mass ratio of the ethanol to the alloy powder in step (2) is 0.9:1; and the protective gas of the oxygen-containing atmosphere is nitrogen.

[0086] Example 4

[0087] This embodiment provides a samarium-based rare earth permanent magnet material, the composition of the samarium-based rare earth permanent magnet material expressed in atomic ratio is: Sm2Fe α Cu β V γ Mo δ N ε , where α=14, β=0.3, γ=1.5, δ=0.5, ε=3.62.

[0088] The samarium-based rare earth permanent magnet material is obtained by the following preparation method, which comprises the following steps:

[0089] (1) mixing metal samarium powder, iron powder, copper powder, vanadium powder and molybdenum powder according to the formula, smelting at 1400°C for 70 minutes in an argon atmosphere and rapidly solidifying ingots to obtain alloy sheets;

[0090] (2) The alloy flakes obtained in step (1) were subjected to mechanical crushing, air flow milling under argon protection, nitriding, and ball milling in an argon atmosphere to obtain an alloy powder with an average particle size of 2 μm;

[0091] The average particle size of the powder particles obtained by the jet mill is 50 μm; the nitriding includes a first heat treatment and a second heat treatment performed in sequence; the first heat treatment is: in an ammonia atmosphere, the temperature is raised to 500° C. and kept at this temperature for 10 hours; the second heat treatment is: in an argon atmosphere, the temperature is lowered to 400° C. and kept at this temperature for 70 minutes;

[0092] (3) The alloy powder obtained in step (2) is sequentially subjected to phosphating, heat treatment in an oxygen-containing atmosphere with an oxygen concentration of 50 ppm to 140° C., heat preservation for 4.5 hours, and cooling to obtain the samarium-based rare earth permanent magnet material;

[0093] The phosphating step comprises: mixing and heating phosphoric acid, ethanol and the alloy powder obtained in step (2) in a nitrogen atmosphere, heating at 78° C. until the ethanol volatilizes, and obtaining the phosphated alloy powder; the mass of the phosphoric acid is 3.5 wt % of the mass of the alloy powder in step (2); the mass ratio of the ethanol to the alloy powder in step (2) is 1.2:1; and the protective gas of the oxygen-containing atmosphere is nitrogen.

[0094] Example 5

[0095] This embodiment provides a samarium-based rare earth permanent magnet material, the composition of the samarium-based rare earth permanent magnet material expressed in atomic ratio is: Sm2Fe α Cu β V γ Mo δ N ε , where α=14, β=0.3, γ=1.5, δ=0.5, ε=3.21.

[0096] The samarium-based rare earth permanent magnet material is obtained by the following preparation method, which comprises the following steps:

[0097] (1) mixing metal samarium powder, iron powder, copper powder, vanadium powder and molybdenum powder according to the formula, melting at 1600°C for 50 minutes in an argon atmosphere and rapidly solidifying into an ingot to obtain an alloy sheet;

[0098] (2) The alloy flakes obtained in step (1) were subjected to mechanical crushing, air flow milling under argon protection, nitriding, and ball milling in an argon atmosphere to obtain an alloy powder with an average particle size of 4 μm;

[0099] The average particle size of the powder particles obtained by the jet mill is 100 μm. The nitriding includes a first heat treatment and a second heat treatment performed sequentially. The first heat treatment is: heating to 550° C. in an ammonia atmosphere and holding the temperature for 4 hours; the second heat treatment is: cooling to 450° C. in an argon atmosphere and holding the temperature for 50 minutes.

[0100] (3) The alloy powder obtained in step (2) is sequentially subjected to phosphating, heat treatment in an oxygen-containing atmosphere with an oxygen concentration of 100 ppm to 160° C., heat preservation for 3.5 hours, and cooling to obtain the samarium-based rare earth permanent magnet material;

[0101] The phosphating step comprises: mixing and heating phosphoric acid, ethanol and the alloy powder obtained in step (2) in a nitrogen atmosphere, heating at 82° C. until the ethanol volatilizes, and obtaining the phosphated alloy powder; the mass of the phosphoric acid is 2.5 wt % of the mass of the alloy powder in step (2); the mass ratio of the ethanol to the alloy powder in step (2) is 0.8:1; and the protective gas of the oxygen-containing atmosphere is nitrogen.

[0102] Example 6

[0103] This embodiment provides a samarium-based rare earth permanent magnet material. The difference from the embodiment 1 is that the composition of the samarium-based rare earth permanent magnet material expressed in atomic ratio is: Sm2Fe α Cu β V γ N ε , where α=11.5, β=0.1, γ=1.0, ε=4.20, and the rest are the same as in Example 1.

[0104] Example 7

[0105] This embodiment provides a samarium-based rare earth permanent magnet material. The difference from the embodiment 1 is that the composition of the samarium-based rare earth permanent magnet material expressed in atomic ratio is: Sm2Fe α Cu β V γ Mo δ N ε , where α=17.5, β=0.4, γ=1.8, δ=1.0, ε=2.90, and the rest are the same as in Example 1.

[0106] Example 8

[0107] This embodiment provides a samarium-based rare earth permanent magnet material, which differs from Example 1 in that ε in the samarium-based rare earth permanent magnet material is 2.68, and the heating and holding stages in the preparation method of the samarium-based rare earth permanent magnet material are: heating to 480°C and holding for 7 hours in an ammonia atmosphere. The rest is the same as Example 1.

[0108] Example 9

[0109] This embodiment provides a samarium-based rare earth permanent magnet material, which differs from Example 1 in that ε=2.65 in the samarium-based rare earth permanent magnet material, and the heating and holding stages in the preparation method of the samarium-based rare earth permanent magnet material are: heating to 570°C and holding for 7 hours in an ammonia atmosphere. The rest is the same as Example 1.

[0110] Example 10

[0111] This embodiment provides a samarium-based rare earth permanent magnet material, which differs from Example 1 in that ε=2.85 in the samarium-based rare earth permanent magnet material, and the heating and holding stages in the preparation method of the samarium-based rare earth permanent magnet material are: heating to 520°C and holding for 2 hours in an ammonia atmosphere. The rest is the same as Example 1.

[0112] Example 11

[0113] This embodiment provides a samarium-based rare earth permanent magnet material, which differs from Example 1 in that ε in the samarium-based rare earth permanent magnet material is 2.67. The heating and heat preservation stages in the preparation method of the samarium-based rare earth permanent magnet material are: heating to 520°C and keeping warm for 12 hours in an ammonia atmosphere. The rest are the same as in Example 1.

[0114] Example 12

[0115] This embodiment provides a samarium-based rare earth permanent magnet material, which differs from Example 1 in that ε in the samarium-based rare earth permanent magnet material is 3.75, and in the preparation method of the samarium-based rare earth permanent magnet material, the average particle size of the alloy powder is adjusted to 1 μm. The rest is the same as Example 1.

[0116] Example 13

[0117] This embodiment provides a samarium-based rare earth permanent magnet material, which differs from Example 1 in that ε in the samarium-based rare earth permanent magnet material is 3.75, and in the preparation method of the samarium-based rare earth permanent magnet material, the average particle size of the alloy powder is adjusted to 5 μm. The rest is the same as Example 1.

[0118] Example 14

[0119] This embodiment provides a samarium-based rare earth permanent magnet material, which differs from Example 1 in that ε in the samarium-based rare earth permanent magnet material is 3.75, and the oxygen concentration in the mixed atmosphere in the preparation method of the samarium-based rare earth permanent magnet material is adjusted to 30 ppm. The rest is the same as Example 1.

[0120] Example 15

[0121] This embodiment provides a samarium-based rare earth permanent magnet material, which differs from Example 1 in that ε in the samarium-based rare earth permanent magnet material is 3.75, and the oxygen concentration in the mixed atmosphere in the preparation method of the samarium-based rare earth permanent magnet material is adjusted to 120 ppm. The rest is the same as Example 1.

[0122] Comparative Example 1

[0123] This comparative example provides a samarium-based rare earth permanent magnet material. The difference from Example 1 is that the samarium-based rare earth permanent magnet material has the following components expressed in atomic ratio: Sm2Fe α Cu β Al γ N ε , where α=15, β=0.3, γ=2, ε=3.57, and the rest are the same as in Example 1.

[0124] Comparative Example 2

[0125] This comparative example provides a samarium-based rare earth permanent magnet material. The difference from Example 1 is that the samarium-based rare earth permanent magnet material has the following components expressed in atomic ratio: Sm 1.8 Nd 0.2 Fe α Co β V γ Cr δ N ε , where α=15, β=0.5, γ=1.5, δ=0.5, ε=3.32, and the rest are the same as in Example 1.

[0126] Comparative Example 3

[0127] This comparative example provides a samarium-based rare earth permanent magnet material, which differs from Example 1 in that ε in the samarium-based rare earth permanent magnet material is 3.65, and the preparation method of the samarium-based rare earth permanent magnet material does not include step (3), and the rest is the same as Example 1.

[0128] The samarium-based rare earth permanent magnet materials provided in Examples 1-15 and Comparative Examples 1-3 were mixed with an epoxy resin binder in a mass ratio of 9:1, and then pressed into Φ10×10m cylinders under a magnetic field of 1.5T. The magnetic properties were tested using a BH tester. The results are shown in Table 1.

[0129] Table 1

[0130]

[0131]

[0132] As can be seen from Table 1, the samarium-based rare earth permanent magnet material provided by the present invention can achieve an optimal balance between remanence and coercive force, the magnet contains large energy, and has excellent comprehensive magnetic properties, which can meet the performance requirements of a permanent magnet material.

[0133] From the comparison between Example 1 and Examples 2-5, it can be seen that by controlling the preparation process parameters such as ball milling particle size, heating temperature and holding time within a reasonable range, it is possible to ensure that both the remanence and coercivity reach a good state;

[0134] By comparing Example 1 with Example 6 and Example 7, it can be seen that the introduction of copper, vanadium and molybdenum elements and their reasonable atomic ratio make the samarium-based rare earth permanent magnet material have good magnetic properties; by comparing Example 1 with Examples 8-11, it can be seen that the heating temperature and the holding time have a greater influence on the nitrogen content. If the heating temperature is too high or too low, or the holding time is too long or too short, the samarium-based rare earth permanent magnet material cannot reach an appropriate nitrogen content, thereby making it difficult to ensure the magnetic properties of the material; by comparing Example 1 with Example 12 and Example 13, it can be seen that if the ball milling particle size is too small, the coercive force of the magnetic powder increases, but the remanence decreases significantly; if the ball milling particle size is too large, the remanence of the magnetic powder increases slightly, but the coercive force decreases significantly; by comparing Example 1 with Example 14 and Example 15, it can be seen that the oxygen concentration of the mixed atmosphere in the heat treatment process has a certain influence on the antioxidant effect of the samarium-based rare earth permanent magnet material. Too high or too low an oxygen concentration is not conducive to slight oxidation of the magnetic powder surface, thereby reducing the magnetic properties of the material;

[0135] By comparing Example 1 with Comparative Example 1 and Comparative Example 2, it can be seen that the use of other doping elements changes the microstructure of the material, and its comprehensive magnetic properties are lower than the comprehensive magnetic properties of the samarium-based rare earth permanent magnet material provided by the present invention; by comparing Example 1 with Comparative Example 3, it can be seen that the alloy powder that has not been phosphating and heat treated has poor oxidation resistance, which further deteriorates the comprehensive magnetic properties of the material.

[0136] In summary, the samarium-based rare earth permanent magnet material provided by the present invention has excellent comprehensive magnetic properties by doping vanadium, copper and molybdenum elements and regulating the appropriate atomic ratio range. The remanence can reach 7180Gs, the coercive force is 10350Oe, and the magnetic energy product can reach 12.3MGOe.

[0137] The phosphating and heat treatment processes can effectively improve the antioxidant effect of samarium-based rare earth permanent magnet materials; by regulating the heating temperature and time of the nitriding process and controlling the ball milling particle size, a good balance between remanence and coercive force is achieved, thereby obtaining excellent magnetic properties. The preparation method provided by the present invention is simple to operate and has low cost, and is suitable for the fields of micro motors, magnetic sensors or audio equipment.

[0138] The above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention fall within the protection scope and disclosure scope of the present invention.

Claims

1. A samarium-based rare earth permanent magnet material, characterized in that: The composition of the samarium-based rare earth permanent magnet material expressed in atomic ratio is: Sm2Fe α Cu β V γ Mo δ N ε , where 11.5≤α≤17.5, 0.1≤β≤0.4, 1.0≤γ≤1.8, 0≤δ≤1.0, 2.9≤ε≤4.0; The samarium-based rare earth permanent magnet material is prepared by the following preparation method, which comprises the following steps: (1) mixing metal samarium powder, iron powder, copper powder, vanadium powder and molybdenum powder according to the formula, and sequentially melting and rapidly solidifying ingots to obtain alloy sheets; (2) The alloy flakes obtained in step (1) are crushed, nitrided, and ball-milled in sequence to obtain alloy powder; (3) The alloy powder obtained in step (2) is sequentially subjected to phosphating and heat treatment, and then cooled to obtain the samarium-based rare earth permanent magnet material; The heat treatment in step (3) is carried out in an oxygen-containing atmosphere, the protective gas of the oxygen-containing atmosphere is nitrogen; the concentration of oxygen in the oxygen-containing atmosphere is 50-100 ppm.

2. A method for preparing the samarium-based rare earth permanent magnet material according to claim 1, characterized in that: The preparation method comprises the following steps: (1) mixing metal samarium powder, iron powder, copper powder, vanadium powder and molybdenum powder according to the formula, and sequentially melting and rapidly solidifying ingots to obtain alloy sheets; (2) The alloy flakes obtained in step (1) are crushed, nitrided, and ball-milled in sequence to obtain alloy powder; (3) The alloy powder obtained in step (2) is sequentially subjected to phosphating and heat treatment, and then cooled to obtain the samarium-based rare earth permanent magnet material; The heat treatment in step (3) is carried out in an oxygen-containing atmosphere, the protective gas of the oxygen-containing atmosphere is nitrogen; the concentration of oxygen in the oxygen-containing atmosphere is 50-100 ppm.

3. The preparation method according to claim 2, characterized in that The smelting temperature in step (1) is 1400-1600°C.

4. The preparation method according to claim 2, characterized in that The smelting time in step (1) is 50-70 minutes.

5. The preparation method according to claim 2, characterized in that The smelting in step (1) is carried out in an argon atmosphere.

6. The preparation method according to claim 2, characterized in that The pulverizing step in step (2) is as follows: the alloy flakes obtained in step (1) are subjected to mechanical crushing and air flow grinding in sequence to obtain powder particles.

7. The preparation method according to claim 6, characterized in that The average particle size of the powder particles is 50-100 μm.

8. The preparation method according to claim 6, characterized in that The jet milling is carried out in an argon atmosphere.

9. The preparation method according to claim 2, characterized in that The nitriding in step (2) includes a first heat treatment and a second heat treatment performed sequentially.

10. The preparation method according to claim 9, characterized in that The first heat treatment is: heating to 500-550° C. in an ammonia atmosphere and keeping the temperature for 4-10 hours.

11. The preparation method according to claim 9, characterized in that The second heat treatment is: cooling to 400-450° C. and keeping the temperature for 50-70 minutes under an argon atmosphere.

12. The preparation method according to claim 2, characterized in that The ball milling in step (2) is carried out in an argon atmosphere.

13. The preparation method according to claim 2, characterized in that The average particle size of the alloy powder in step (2) is 2-4 μm.

14. The preparation method according to claim 2, characterized in that The phosphating step in step (3) is as follows: mixing phosphoric acid, a solvent and the alloy powder obtained in step (2), heating until the solvent evaporates, and obtaining the phosphated alloy powder.

15. The preparation method according to claim 14, characterized in that The mass of the phosphoric acid is 2.5-3.5 wt % of the mass of the alloy powder in step (2).

16. The preparation method according to claim 14, characterized in that The mass ratio of the solvent to the alloy powder in step (2) is (0.8-1.2):

1.

17. The preparation method according to claim 14, characterized in that The solvent includes ethanol.

18. The preparation method according to claim 14, characterized in that The terminal temperature of the heating is 78-82°C.

19. The preparation method according to claim 2, characterized in that: The phosphating in step (3) is carried out in a nitrogen atmosphere.

20. The preparation method according to claim 2, characterized in that The terminal temperature of the heat treatment in step (3) is 140-160°C.

21. The preparation method according to claim 2, characterized in that The holding time of the heat treatment in step (3) is 3.5-4.5h.

22. The preparation method according to claim 2, characterized in that The preparation method comprises the following steps: (1) mixing metal samarium powder, iron powder, copper powder, vanadium powder and molybdenum powder according to the formula, smelting at 1400-1600°C for 50-70 minutes in an argon atmosphere, and rapidly solidifying ingots to obtain alloy sheets; (2) The alloy flakes obtained in step (1) were subjected to mechanical crushing, air flow milling, nitriding, and ball milling in an argon atmosphere to obtain an alloy powder with an average particle size of 2-4 μm; The average particle size of the powder particles obtained by the jet mill is 50-100 μm; the nitriding includes a first heat treatment and a second heat treatment performed in sequence; the first heat treatment is: in an ammonia atmosphere, the temperature is raised to 500-550° C. and kept at this temperature for 4-10 hours; the second heat treatment is: in an argon atmosphere, the temperature is lowered to 400-450° C. and kept at this temperature for 50-70 minutes; (3) The alloy powder obtained in step (2) is sequentially subjected to phosphating, heat treatment in an oxygen-containing atmosphere with an oxygen concentration of 50-100 ppm to a temperature of 140-160° C., heat preservation for 3.5-4.5 hours, and cooling to obtain the samarium-based rare earth permanent magnet material; the protective gas of the oxygen-containing atmosphere is nitrogen; The phosphating step comprises: mixing phosphoric acid, a solvent and the alloy powder obtained in step (2) in a nitrogen atmosphere, and heating until the solvent evaporates to obtain a phosphated alloy powder; the mass of the phosphoric acid is 2.5-3.5wt% of the mass of the alloy powder in step (2); and the mass ratio of the solvent to the alloy powder in step (2) is (0.8-1.2):

1.

23. An application of the samarium-based rare earth permanent magnet material according to claim 1, characterized in that: The samarium-based rare earth permanent magnet material is used in the fields of micro motors, magnetic sensors or audio equipment.

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