Preparation method of high-performance diffusion Sm-Co composite permanent magnet

Abstract

The application discloses a preparation method of a high-performance diffusion Sm-Co composite permanent magnet, and comprises the following steps: mixing alloy components according to (Sm, Re)2(Co, A) 17 After the alloy components are mixed, a proper amount of BiI3 is added, magnetic field orientation forming is carried out, and a Sm-Co magnet green body is obtained; the Sm-Co magnet green body is vacuum pre-fired under certain temperature conditions, and a magnet with a network channel structure in the interior is formed; a soft magnetic phase nano-level Fe or Co powder is mixed with an organic solvent to form a diffusion source mixed solution, the pre-fired Sm-Co magnet is immersed into the mixed solution, and after being taken out, the Sm-Co magnet is placed into a vacuum oven and dried. The BiI3 sublimation technology is used to make the soft magnetic phase and the doped elements effectively enter the grain boundary of the Sm-Co magnet, improve the coupling effect and pinning effect of the soft and hard magnetic phases, and improve the coercive force and maximum magnetic energy product. The preparation method is simple in process, low in cost, less in introduced impurities, and capable of maintaining the magnetic performance of the hard magnetic phase to the maximum extent.

Description

Technical Field

[0001] This invention relates to the field of magnetic materials technology, specifically to a method for preparing a high-performance diffused samarium-cobalt composite permanent magnet. Background Technology

[0002] Samarium-cobalt magnets, as a second-generation rare earth product, are magnetic materials made by alloying samarium, cobalt, and other rare earth metals, followed by crushing, molding, and sintering. They possess advantages such as high magnetic energy product and extremely low temperature coefficient. At operating temperatures above 180℃, their temperature and chemical stability surpass those of neodymium-iron-boron permanent magnets. Furthermore, they exhibit corrosion and oxidation resistance and have been widely applied in aerospace, defense, microwave devices, communications, and medical equipment.

[0003] Existing sintered 2:17 type Sm-Co magnets are mainly prepared using powder metallurgy methods. The main process involves batching, alloy melting, alloy crushing and powdering, powder orientation molding, and heat treatment. However, the actual yield is far less than the theoretical calculation. We introduced BiI3 during the pre-sintering process; as the temperature rises, BiI3 sublimates into a gas, and the BiI3 molecules in Sm2Co... 17 A network of channels is formed within the magnet. This allows the soft magnetic phase and dopant elements to diffuse better into the interior and surface of the magnet, thereby improving the Sm2Co... 17 The coercivity and maximum energy product of a magnet. Summary of the Invention

[0004] The technical problem to be solved by the present invention is a method for preparing a high-performance diffused samarium cobalt composite permanent magnet, which can effectively overcome the shortcomings of the prior art.

[0005] This invention is achieved through the following technical solution: a method for preparing a high-performance diffused samarium-cobalt composite permanent magnet, comprising the following steps:

[0006] S1. Batching stage: (Sm, Re) and (Co, A) alloy powders are mixed in an atomic ratio of 2:17, and an appropriate amount of BiI3 is added. After magnetic field orientation molding, a samarium cobalt magnet green blank is obtained.

[0007] S2, Pre-firing stage: The samarium cobalt magnet blank is vacuum pre-firing under certain temperature conditions to form a magnet with an internal mesh channel structure;

[0008] S3. Coating stage: Mix soft magnetic phase nanoscale Fe or Co powder with organic solvent to form a diffusion source mixed solution. Immerse the pre-fired samarium cobalt magnet in the mixed solution, take it out and put it in a vacuum oven to dry. Repeat 3 to 5 times.

[0009] S4. Sintering and diffusion stage: The coated magnet is heat-treated under argon protection and a strong magnetic field to obtain a samarium cobalt composite permanent magnet.

[0010] As a preferred technical solution, Re in S1 is one or more of rare earth elements such as La, Dy, Tb, Er, Ce, Nd, Gd and Y.

[0011] As a preferred technical solution, in S1, the atomic ratio of Sm to Re is 1:0.0~0.2, the atomic proportion of Co in (Co, A) is 70~95%, and A is one or more of the elements Co, Ni, Cu, Fe, Zn, Ti, Ga, and Ge.

[0012] As a preferred technical solution, in S1, BiI3 accounts for 0.1-3 wt% of the mass fraction in the magnet. The samarium cobalt magnetic powder is fully oriented and pressed into shape under a magnetic field of 1-10 T. The size of the blank is 5-50 mm in diameter and 1 mm or more and less than 10 mm in thickness.

[0013] As a preferred technical solution, in S2, the pre-firing vacuum degree is 10⁻⁵~10⁻³ Pa, the pre-firing temperature is 500~600℃, and the time is 2~3 h, during which BiI₃ volatilizes and forms a mesh channel inside the magnet.

[0014] As a preferred technical solution, in S3, the soft magnetic phase is one or both of Fe or Co, with a particle size of 10nm~200nm, the organic solvent is acetone or ethanol solution, the temperature of the vacuum oven is 100~150°C, and the drying time for a single drying is 10~30 minutes.

[0015] As a preferred technical solution, in S4, the strong magnetic field is 6~12T, the heat treatment temperature is 500~800℃, and the heat treatment time is 6~11h.

[0016] The beneficial effects of the present invention are: (1) The experimental method used in the present invention is simple, introduces fewer impurity phases, and can maintain the magnetic properties of the hard magnetic phase to the greatest extent;

[0017] (2) The method for preparing high-performance Sm2Co17 composite magnet materials by BiI3 sublimation is simple and low-cost.

[0018] (3) By sublimating BiI3, the soft magnetic phase and doping elements can effectively enter the grain boundary of the samarium cobalt magnet, thereby improving the coupling and pinning effect of the soft and hard magnetic phases, and increasing the coercivity and maximum magnetic energy product. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the diffusion of the samarium cobalt magnet mesh channel according to the present invention. Detailed Implementation

[0021] All features disclosed in this specification, or steps in all methods or processes disclosed herein, may be combined in any way, except for mutually exclusive features and / or steps.

[0022] Any feature disclosed in this specification (including any appended claims, abstract, and drawings) may be replaced by other equivalent or similar features for a similar purpose, unless specifically stated otherwise. That is, unless specifically stated otherwise, each feature is merely one example of a series of equivalent or similar features.

[0023] In the description of this invention, it should be understood that the terms "one end", "the other end", "outer side", "upper", "inner side", "horizontal", "coaxial", "center", "end", "length", "outer end", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0024] Furthermore, in the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0025] The terms used in this invention, such as “above,” “over,” “below,” and “under,” indicating spatial relative position, are for ease of description to depict the relationship of one unit or feature relative to another unit or feature as shown in the accompanying drawings. The terms of spatial relative position may be intended to include different orientations of the device in use or operation other than those shown in the figures. For example, if the device in the figures is flipped, a unit described as being “below” or “under” other units or features would be located “above” other units or features. Therefore, the exemplary term “under” can encompass both above and below orientations. The device may be oriented in other ways (rotated 90 degrees or otherwise), and the spatially related descriptive terms used herein will be interpreted accordingly.

[0026] In this invention, unless otherwise explicitly specified and limited, the terms "set," "socket," "connect," "through," and "plug-in" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0027] like Figure 1 As shown in Example 1: A method for preparing a high-performance diffused samarium-cobalt composite permanent magnet, comprising the following steps:

[0028] Step (1) Ingredient preparation stage: According to (Sm, Ce)2(Co, Fe, Mn, Cu) 17 After the alloy components are mixed, BiI3 powder with a mass fraction of 1% of the magnetic powder is added. The mixture is fully oriented under a 2T magnetic field and pressed into a samarium-cobalt green blank with a diameter of 30mm and a thickness of 5mm. The atomic ratio of Sm:Tb is 1:0.1 (Co,Fe,Mn,Cu). 17 Co accounts for 70% of the atomic composition, while Fe, Mn, and Cu account for 2%, 17%, and 11% respectively.

[0029] Step (2) Pre-firing stage: The samarium cobalt magnet green blank is fired in a vacuum of 10 -4 Pa is pre-fired at 550°C for 3 hours to form a magnet with an internal mesh channel structure.

[0030] Step (3) Coating stage: Immerse the samarium cobalt magnet in the diffusion source solution formed by Fe powder and acetone, take it out and put it in a vacuum oven at 100°C for drying. Repeat 4 times, and the drying time is 15 minutes.

[0031] Step (4) Sintering and diffusion stage: Under argon protection and strong magnetic field (7T), heat treatment is carried out for 8 h at a temperature of 600℃ to obtain a high-performance diffused samarium cobalt composite permanent magnet.

[0032] Comparative Example 1:

[0033] The preparation steps are the same as in Example 1, except that in step (1), BiI3 powder is not added, and the diffused metal Fe powder is directly coated on the surface of the magnet.

[0034] Example 2:

[0035] Step (1) Ingredient preparation stage: According to (Sm, Er)2(Co, Cu, Fe, Zn) 17After the alloy components are mixed, BiI3 powder with a mass fraction of 2% of the magnetic powder is added. The mixture is fully oriented under a 5T magnetic field and pressed into a samarium-cobalt green blank with a diameter of 40mm and a thickness of 4mm. The atomic ratio of Sm:Gd is 1:0.15 (Co, Cu, Fe, Zn). 17 The atomic percentage of Co is 80%, while that of Cu, Fe, and Zn is 7%, 3%, and 10%, respectively.

[0036] Step (2) Pre-firing stage: The samarium cobalt magnet green blank is fired in a vacuum of 10 -3 Pa is pre-fired at 600℃ for 2.5 h to form a magnet with an internal mesh channel structure.

[0037] Step (3) Coating stage: Immerse the samarium cobalt magnet in the diffusion source solution formed by Co powder and ethanol, take it out and put it in a vacuum oven at 120°C to dry, repeat 5 times, and the drying time is 20 minutes.

[0038] Step (4) Sintering and diffusion stage: Under argon protection and strong magnetic field (8T), heat treatment is carried out for 7 h at a temperature of 650℃ to obtain a high-performance diffused samarium cobalt composite permanent magnet.

[0039] Comparative Example 2:

[0040] The preparation steps are the same as in Example 2, except that in step (1), BiI3 powder is not added, and the diffused metal Co powder is directly coated on the surface of the magnet.

[0041] Magnetic properties of samarium cobalt magnets obtained by diffusion process (Comparative Example 1, Example 2).

[0042]

[0043] The beneficial effects of the present invention are: (1) The experimental method used in the present invention is simple, introduces fewer impurity phases, and can maintain the magnetic properties of the hard magnetic phase to the greatest extent;

[0044] (2) The method for preparing high-performance Sm2Co17 composite magnet materials by BiI3 sublimation is simple and low-cost.

[0045] (3) By sublimating BiI3, the soft magnetic phase and doping elements can effectively enter the grain boundary of the samarium cobalt magnet, thereby improving the coupling and pinning effect of the soft and hard magnetic phases, and increasing the coercivity and maximum magnetic energy product.

[0046] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions conceived without inventive effort should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A method for preparing a high-performance diffused samarium-cobalt composite permanent magnet, characterized in that, It includes the following steps: S1. Batching stage: Mix (Sm, Re) and (Co, A) alloy powders in an atomic ratio of 2:17, add an appropriate amount of BiI3, and shape them by magnetic field orientation to obtain samarium cobalt magnet green blanks; S2, Pre-firing stage: The samarium cobalt magnet blank is vacuum pre-firing under certain temperature conditions to form a magnet with an internal mesh channel structure; S3. Coating stage: Mix soft magnetic phase nanoscale Fe or Co powder with organic solvent to form a diffusion source mixed solution. Immerse the pre-fired samarium cobalt magnet in the mixed solution, take it out and put it in a vacuum oven to dry. Repeat 3 to 5 times. S4. Sintering and diffusion stage: The coated magnet is heat-treated under argon protection and a strong magnetic field to obtain a samarium cobalt composite permanent magnet. In S1, BiI3 accounts for 0.1-3 wt% of the mass fraction in the magnet. The samarium cobalt magnetic powder is fully oriented and pressed into shape under a magnetic field of 1-10 T. The size of the blank is 5-50 mm in diameter and 1 mm or more and less than 10 mm in thickness.

2. The method for preparing the high-performance diffused samarium-cobalt composite permanent magnet according to claim 1, characterized in that: In S1, Re is one or more of the rare earth elements La, Dy, Tb, Er, Ce, Nd, Gd, and Y.

3. The method for preparing the high-performance diffused samarium-cobalt composite permanent magnet according to claim 1, characterized in that: In S1, the atomic ratio of Sm to Re is 1:0.0~0.2, and the atomic percentage of Co in (Co, A) is 70~95%, while A is one or more of the elements Co, Ni, Cu, Fe, Zn, Ti, Ga, and Ge.

4. The method for preparing the high-performance diffused samarium-cobalt composite permanent magnet according to claim 1, characterized in that: In S2, the pre-burning vacuum degree is 10. -5 ~10 -3 Pa, the pre-firing temperature is 500~600℃, the time is 2~3 h, BiI3 volatilizes, forming a mesh channel inside the magnet.

5. The method for preparing a high-performance diffused samarium-cobalt composite permanent magnet according to claim 1, characterized in that: In S3, the soft magnetic phase is one or both of Fe and Co, with a particle size of 10 nm to 200 nm. The organic solvent is acetone or ethanol solution, and the temperature of the vacuum oven is 100 to 150 °C. o C. The drying time for a single cycle is 10-30 minutes.

6. The method for preparing a high-performance diffused samarium-cobalt composite permanent magnet according to claim 1, characterized in that: In S4, the strong magnetic field is 6~12T, the heat treatment temperature is 500~800℃, and the heat treatment time is 6~11h.

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