CN116631758A - Preparation method of samarium cobalt magnetic steel - Google Patents

Preparation method of samarium cobalt magnetic steel Download PDF

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CN116631758A
CN116631758A CN202310492925.1A CN202310492925A CN116631758A CN 116631758 A CN116631758 A CN 116631758A CN 202310492925 A CN202310492925 A CN 202310492925A CN 116631758 A CN116631758 A CN 116631758A
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samarium cobalt
powder
steel ingot
steel
magnetic steel
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姚溥
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Beijing Jingci Electrical Technology Co ltd
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Beijing Jingci Electrical Technology Co ltd
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
    • H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
    • H01F41/0253—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets for manufacturing permanent magnets
    • H01F41/0266—Moulding; Pressing
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/032—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials
    • H01F1/04—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials metals or alloys
    • H01F1/047—Alloys characterised by their composition
    • H01F1/053—Alloys characterised by their composition containing rare earth metals
    • H01F1/055—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5
    • H01F1/0555—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 pressed, sintered or bonded together
    • H01F1/0556—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 pressed, sintered or bonded together pressed
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/032—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials
    • H01F1/04—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials metals or alloys
    • H01F1/047—Alloys characterised by their composition
    • H01F1/053—Alloys characterised by their composition containing rare earth metals
    • H01F1/055—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5
    • H01F1/0555—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 pressed, sintered or bonded together
    • H01F1/0557—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 pressed, sintered or bonded together sintered
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/032—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials
    • H01F1/04—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials metals or alloys
    • H01F1/047—Alloys characterised by their composition
    • H01F1/053—Alloys characterised by their composition containing rare earth metals
    • H01F1/055—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5
    • H01F1/059—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and Va elements, e.g. Sm2Fe17N2
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F13/00—Apparatus or processes for magnetising or demagnetising
    • H01F13/003—Methods and devices for magnetising permanent magnets

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Hard Magnetic Materials (AREA)

Abstract

The invention discloses a preparation method of samarium cobalt magnetic steel, which comprises the following steps: respectively preparing steel ingots A and B with different components, mixing and crushing the steel ingots A and B, pulverizing, compacting, sintering, solid-dissolving, and tempering to obtain samarium cobalt magnetic steel, wherein the steel ingot A is prepared from the following ingredients in percentage by mass: 23-28% of Sm, 14-19% of Fe, 5-7% of Cu, 2-3% of Zr and the balance of Co, and the ingredients for preparing the steel ingot B comprise the following components in percentage by mass: 25-30% of Sm, 16-21% of Fe, 4-6% of Cu and the balance of Co, wherein when the steel ingot A and the steel ingot B are mixed and crushed, the mass percentage of the steel ingot A is 80-90%. The preparation method of the samarium cobalt magnetic steel can enable the intrinsic coercivity to be adjustable and controllable on the premise of not introducing other rare earth elements, has low requirement on magnetizing equipment, is simple to operate, and is suitable for mass production.

Description

Preparation method of samarium cobalt magnetic steel
Technical Field
The invention relates to the technical field of samarium cobalt permanent magnets. More particularly, the invention relates to a preparation method of samarium cobalt magnetic steel.
Background
The samarium cobalt permanent magnet has excellent high-temperature magnetic property, lower temperature coefficient, good oxidation resistance and corrosion resistance, and the maximum working temperature can reach 350 ℃, and is widely applied to the fields of aerospace, national defense and military industry, high-end motors and the like. At present, the highest coercivity of a commercially produced high-performance 2:17 samarium cobalt magnet can be more than 35kOe, and for certain samarium cobalt magnet application fields, 25-30 kOe can meet the requirements of room temperature and high temperature use, the requirement on magnetizing equipment can be increased due to larger intrinsic coercivity, the common magnetizing equipment causes unsaturated magnetizing of the magnet, the magnet fails in the use process, and the high-performance 2:17 samarium cobalt magnet has great significance in adjusting the intrinsic coercivity according to the use environment requirement. In the existing patents, such as the Chinese patent with the application publication number of CN101882494A, a single alloy method is adopted to add heavy rare earth elements to improve the coercive force and reduce the temperature coefficient, but the method can not regulate the coercive force.
Disclosure of Invention
The invention aims to provide a preparation method of samarium cobalt magnetic steel, which does not need to introduce other rare earth metals, has adjustable intrinsic coercivity, has low requirement on magnetizing equipment, is simple to operate and is suitable for mass production.
To achieve these objects and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, there is provided a method for preparing samarium cobalt magnetic steel according to one aspect of the invention, comprising the steps of: respectively preparing steel ingots A and B with different components, mixing and crushing the steel ingots A and B, pulverizing, compacting, sintering, solid-dissolving, and tempering to obtain samarium cobalt magnetic steel, wherein the steel ingot A is prepared from the following ingredients in percentage by mass: 23-28% of Sm, 14-19% of Fe, 5-7% of Cu, 2-3% of Zr and the balance of Co, and the ingredients for preparing the steel ingot B comprise the following components in percentage by mass: 25-30% of Sm, 16-21% of Fe, 4-6% of Cu and the balance of Co, wherein when the steel ingot A and the steel ingot B are mixed and crushed, the mass percentage of the steel ingot A is 80-90%.
Preferably, the thickness of the steel ingot A and the steel ingot B is 10-20 mm.
Preferably, argon is used for protection in the crushing process, and the particle size of coarse particles formed after crushing is smaller than 4mm.
Preferably, the specific steps of the powder preparation are as follows:
step one, mixing and crushing a steel ingot A and a steel ingot B to form coarse particles, and performing medium crushing to obtain powder with the particle size smaller than 200 mu m;
adding a first additive accounting for 0.01-0.015% of the mass of the powder into the powder, mixing for 1-2 h by using a three-dimensional powder mixer, and standing for 2-4 h, wherein the first additive is mixed liquid of n-hexane and methyl decanoate in a mass ratio of 4:1;
and thirdly, continuing to perform air flow grinding to prepare powder, adding 2000-5000 ppm of dry oxygen, adding a second additive accounting for 0.01-0.015% of the mass of the fine powder into the prepared fine powder, and mixing for 2-3 hours by using a three-dimensional powder mixer to obtain uniformly mixed samarium cobalt alloy powder, wherein the second additive is stearic acid and polyethylene glycol mixed solution with a mass ratio of 3:1.
Preferably, the specific process of the compression molding is as follows: and pressing the samarium cobalt alloy powder obtained by powder preparation by using a closed low-oxygen press, wherein the oxygen content in the closed low-oxygen press is lower than 500ppm, vacuum packaging, and pressing by using a cold isostatic press to finally obtain a pressed compact, and the pressure of the cold isostatic press is 250MPa.
Preferably, the specific processes of sintering, solid solution and tempering heat treatment are as follows: placing the pressed compact in a sintering furnace, preserving heat at 1210 ℃ for 1.5h for sintering treatment, wherein the vacuum degree in the sintering furnace is higher than 2 multiplied by 10 -2 Pa, cooling to 1170 ℃ along with a furnace, carrying out solution treatment, carrying out air cooling to room temperature after heat preservation for 8 hours, then carrying out tempering treatment after heating to 850 ℃, slowly cooling to 400 ℃ along with the furnace after heat preservation for 15 hours, carrying out heat preservation at 400 ℃, and carrying out air cooling to room temperature, thereby finally preparing the samarium cobalt magnetic steel.
Preferably, in the tempering treatment, the cooling speed of slowly cooling to 400 ℃ along with the furnace is less than or equal to 0.7 ℃/min.
Preferably, in the tempering treatment, the heat preservation time at 400 ℃ is more than or equal to 1.5h.
The invention at least comprises the following beneficial effects:
firstly, the samarium cobalt magnet finally obtained by preparing two samarium cobalt steel ingots with different components, weighing the two samarium cobalt steel ingots according to proportion, and carrying out powder preparation, compression molding, sintering, solid solution and tempering is beneficial to mass production because the coercive force is reduced, the remanence is improved, the performances such as maximum magnetic energy product are ensured, the preparation process is simple, and the technical requirement is low.
According to the preparation method of the samarium cobalt magnetic steel, the coercive force of the product can be adjusted by only adjusting the component proportions of the two samarium cobalt steel ingots, other rare earth metal elements are not introduced, and the influence of the other rare earth metal elements on the residual magnetism of the magnet is avoided.
Thirdly, the invention can effectively reduce the intrinsic coercivity (25-30 KOE) of the magnet, but the prepared product still meets the high-temperature use requirement, reduces the requirement on magnetizing equipment, and avoids the failure of the magnet in the use process due to magnetizing unsaturated.
Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention.
Detailed Description
The present invention is described in further detail below with reference to specific embodiments so that those skilled in the art can practice the same by referring to the description.
It will be understood that terms, such as "having," "including," and "comprising," as used herein, do not preclude the presence or addition of one or more other elements or groups thereof.
It should be noted that the experimental methods described in the following embodiments, unless otherwise specified, are all conventional methods, and the reagents and materials, unless otherwise specified, are all commercially available; in the description of the present invention, it should be noted that, unless explicitly stated and limited otherwise, the terms "mounted," "connected," and "disposed" are to be construed broadly, and may be fixedly connected, disposed, or detachably connected, disposed, or integrally connected, disposed, for example. The specific meaning of the above terms in the present invention will be understood in specific cases by those of ordinary skill in the art. The terms "transverse," "longitudinal," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like refer to an orientation or positional relationship merely for convenience of description and to simplify the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore should not be construed as limiting the invention.
Example 1
A preparation method of samarium cobalt magnetic steel comprises the following steps:
(1) Preparation of Steel ingot A
The weight percentages are as follows: preparing raw materials including Sm 24%, fe 15%, cu 6%, zr 2%, co 53%, and preparing a steel ingot A with the thickness of 15mm by using an induction melting furnace;
(2) Preparation of Steel ingot B
The weight percentages are as follows: sm 29%, fe 17%, cu 5% and Co 49%, preparing raw materials, and preparing a steel ingot B with the thickness of 15mm by using an induction melting furnace;
(3) Rough break
Weighing a steel ingot A and a steel ingot B according to a proportion, wherein the mass ratio of the steel ingot A is 90%, coarse crushing is carried out by using a crusher to obtain coarse particles with the average diameter of 3mm, and argon is used for protection in the crushing process;
(4) Pulverizing into powder
The coarse particles are crushed in a middle to obtain powder with an average particle diameter of 150 mu m, a first additive accounting for 0.01% of the mass of the powder (mixed by n-hexane and methyl decanoate according to a mass ratio of 4:1) is added into the powder, a three-dimensional powder mixer is used for mixing for 1h, standing is carried out for 4h, air flow grinding is carried out for milling, 4000ppm of dry oxygen is added, the prepared samarium cobalt fine powder is added with a second additive accounting for 0.015% of the mass (mixed by stearic acid and polyethylene glycol according to a mass ratio of 3:1), and the three-dimensional powder mixer is used for mixing the fine powder for 2h;
(5) Shaping
Pressing the uniformly mixed samarium cobalt alloy powder by using a closed low-oxygen press, wherein the oxygen content in the press is lower than 500ppm, vacuum packaging, and obtaining a pressed compact by using a cold isostatic press, wherein the pressure of the cold isostatic press is 250MPa;
(6) Sintering, solid solution and tempering treatment
Placing the pressed compact in a sintering furnace, preserving heat at 1210 ℃ for 1.5h for sintering treatment, wherein the vacuum degree in the sintering furnace is higher than 2 multiplied by 10 -2 Heating under Pa, cooling to 1170 deg.C, and performing solution treatment, wherein the vacuum degree in sintering furnace is higher than 2×10 - 2 Pa, preserving heat for 8h, then cooling to room temperature by air, then heating to 850 ℃ for tempering treatment, preserving heat for 15h, and then slowly cooling to 400 ℃ along with a furnace at a cooling speed of 0.5 DEG CAnd/min, preserving the temperature at 400 ℃ for 2 hours, and then cooling to room temperature by air to prepare the samarium cobalt magnetic steel.
Example 2
A preparation method of samarium cobalt magnetic steel comprises the following steps:
(1) Preparation of Steel ingot A
The weight percentages are as follows: 28% of Sm, 19% of Fe, 7% of Cu, 3% of Zr and 43% of Co, preparing raw materials, and preparing a steel ingot A with the thickness of 20mm by using an induction melting furnace;
(2) Preparation of Steel ingot B
The weight percentages are as follows: preparing raw materials including Sm 30%, fe 21%, cu 6% and Co 43%, and preparing a steel ingot B with the thickness of 20mm by using an induction melting furnace;
(3) Rough break
Weighing a steel ingot A and a steel ingot B according to a proportion, wherein the mass ratio of the steel ingot A is 90%, coarse crushing is carried out by using a crusher to obtain coarse particles with the average diameter of 4mm, and argon is used for protection in the crushing process;
(4) Pulverizing into powder
The coarse particles are crushed in a middle to obtain powder with an average particle diameter of 180 mu m, a first additive accounting for 0.015% of the mass of the powder (mixed by n-hexane and methyl decanoate according to a mass ratio of 4:1) is added into the powder, a three-dimensional powder mixer is used for mixing for 2 hours, standing is carried out for 4 hours, air flow grinding is carried out for pulverizing, 5000ppm of dry oxygen is added, the prepared samarium cobalt fine powder is added with a second additive accounting for 0.01% of the mass (mixed by stearic acid and polyethylene glycol according to a mass ratio of 3:1), and the three-dimensional powder mixer is used for mixing the fine powder for 2 hours;
(5) Shaping
Pressing the uniformly mixed samarium cobalt alloy powder by using a closed low-oxygen press, wherein the oxygen content in the press is lower than 500ppm, vacuum packaging, and obtaining a pressed compact by using a cold isostatic press, wherein the pressure of the cold isostatic press is 250MPa;
(6) Sintering, solid solution and tempering treatment
Placing the pressed compact in a sintering furnace, preserving heat at 1210 ℃ for 1.5h for sintering treatment, wherein the vacuum degree in the sintering furnace is higher than 2 multiplied by 10 -2 Heating under Pa, cooling to 1170 deg.C, and performing solution treatment, wherein the vacuum degree in sintering furnace is higher than 2×10 - 2 Pa, preserving heat for 8h, then cooling to room temperature by air, heating to 850 ℃ for tempering treatment, preserving heat for 15h, slowly cooling to 400 ℃ along with a furnace, preserving heat for 2.5h at the cooling speed of 0.6 ℃/min, and cooling to room temperature by air to prepare the samarium cobalt magnetic steel.
Example 3
A preparation method of samarium cobalt magnetic steel comprises the following steps:
(1) Preparation of Steel ingot A
The weight percentages are as follows: sm 23%, fe 14%, cu 5%, zr 2%, co 56%, preparing raw materials, and using an induction melting furnace to prepare a steel ingot A with the thickness of 10 mm;
(2) Preparation of Steel ingot B
The weight percentages are as follows: 25% of Sm, 16% of Fe, 4% of Cu and 55% of Co, preparing raw materials, and preparing a steel ingot B with the thickness of 10mm by using an induction melting furnace;
(3) Rough break
Weighing a steel ingot A and a steel ingot B according to a proportion, wherein the mass ratio of the steel ingot A is 90%, coarse crushing is carried out by using a crusher to obtain coarse particles with the average diameter of 2mm, and argon is used for protection in the crushing process;
(4) Pulverizing into powder
Crushing the coarse particles to obtain powder with an average particle size of 180 mu m, adding a first additive accounting for 0.012% of the mass of the powder (mixing n-hexane and methyl decanoate according to a mass ratio of 4:1), mixing for 1.5 hours by a three-dimensional powder mixer, standing for 3 hours, grinding by an air flow, adding 3000ppm of dry oxygen, adding a second additive accounting for 0.01% of the mass of the obtained samarium cobalt fine powder (mixing stearic acid and polyethylene glycol according to a mass ratio of 3:1), and mixing the fine powder for 2 hours by the three-dimensional powder mixer;
(5) Shaping
Pressing the uniformly mixed samarium cobalt alloy powder by using a closed low-oxygen press, wherein the oxygen content in the press is lower than 500ppm, vacuum packaging, and obtaining a pressed compact by using a cold isostatic press, wherein the pressure of the cold isostatic press is 250MPa;
(6) Sintering, solid solution and tempering treatment
Placing the pressed compact into a sintering furnace, preserving heat for 1.5h at 1210 ℃ and feedingSintering the mixture to a vacuum degree higher than 2 x 10 -2 Heating under Pa, cooling to 1170 deg.C, and performing solution treatment, wherein the vacuum degree in sintering furnace is higher than 2×10 - 2 Pa, preserving heat for 8h, then cooling to room temperature by air, heating to 850 ℃ for tempering treatment, preserving heat for 15h, slowly cooling to 400 ℃ along with a furnace, preserving heat for 3h at 400 ℃ at a cooling speed of 0.4 ℃/min, and cooling to room temperature by air to prepare the samarium cobalt magnetic steel.
Example 4
The preparation method of samarium cobalt magnetic steel is different from example 1 in that the mass ratio of steel ingot A during rough breaking is 80%.
Example 5
The preparation method of samarium cobalt magnetic steel is different from example 1 in that the mass ratio of steel ingot A during rough breaking is 85%.
Comparative example 1
The preparation method of the samarium cobalt magnetic steel is different from the preparation method of the embodiment 1 in that only the steel ingot A is prepared, and the steel ingot A is subjected to rough breaking, powder preparation, forming, sintering, solid solution and tempering treatment to prepare the samarium cobalt magnetic steel.
Comparative example 2
The preparation method of samarium cobalt magnetic steel is different from example 1 in that only steel ingot B is prepared, and rough breaking, powder preparation, molding and sintering, solid solution treatment and tempering treatment are performed on steel ingot B to prepare samarium cobalt magnetic steel.
Comparative example 3
The preparation method of samarium cobalt magnetic steel is different from example 1 in that steel ingot B comprises the following components in percentage by mass: sm 29%, fe 16%, cu 4%, zr 2%, co 49%.
Comparative example 4
(4) Pulverizing into powder
The preparation method of samarium cobalt magnetic steel is different from example 1 in that a first additive (n-hexane and methyl decanoate are mixed according to a mass ratio of 4:1) is not added in the powder process.
Comparative example 5
The preparation method of samarium cobalt magnetic steel is different from example 1 in that a second additive (stearic acid and polyethylene glycol are mixed according to a mass ratio of 3:1) is not added in the powder preparation process.
Comparative example 6
The preparation method of samarium cobalt magnetic steel is different from that of example 1 in that a first additive (mixed by n-hexane and methyl decanoate according to a mass ratio of 4:1) and a second additive (mixed by stearic acid and polyethylene glycol according to a mass ratio of 3:1) are not added in the pulverizing process.
Magnet magnetic performance test
The samarium cobalt magnetic steels prepared in examples 1 to 5 and comparative examples 1 to 5 were respectively subjected to relevant magnetic performance parameter tests by using a BH instrument test, and the test results are shown in Table 1 according to the detection standard of XB/T507-2009 2:17 type samarium cobalt permanent magnet materials.
TABLE 1
The test results of examples 1-5 show that the coercive force of the samarium cobalt magnetic steel prepared by the preparation method of the samarium cobalt magnetic steel provided by the invention can be regulated and controlled according to different proportions of the steel ingot A and the steel ingot B, and the flexibility is high. The performance of the embodiment 1 is optimal, zirconium components are removed from a steel ingot B, the iron and copper contents are increased, the residual magnetism of the product can be improved, the copper content is increased, the area of a copper-deficient area at a crystal boundary can be reduced, the knee point coercive force of the product is improved, the component B cannot form a zirconium-rich lamellar phase, the coercive force of the product is further reduced, and meanwhile, the product has good magnetic performance; in examples 4 and 5, the proportion of steel ingot B was increased, the element was diffused into the cellular phase during sintering, the defect of the cellular structure was increased, the intrinsic coercive force and the knee point coercive force of the product were reduced, but the B component could not form a complete cellular structure, and thus the defective area was increased, resulting in poor knee point coercive force.
In comparative example 1, only one steel ingot A is used for preparing samarium cobalt magnetic steel, and the test results of example 1 and comparative example 1 are compared, so that the samarium cobalt magnetic steel prepared in comparative example 1 has higher coercivity, because the proportion of the steel ingot B added in example 1 is small, the components in the steel ingot B are mainly distributed in the middle of component grains of the steel ingot A after mixed powder preparation, and various components are mutually diffused in the sintering process, so that the cellular structure of the component grains of the steel ingot A is influenced (the cell wall phase in the cellular structure is mainly influenced, the components in the cell wall phase are changed, and the main phase is not influenced), and the cell main phase in the cellular structure of the product influences the remanence and magnetic energy product of the product, and the cell wall phase influences the coercivity of the product.
In comparative example 2, although the coercive force and the knee point coercive force are the lowest, it is well known to those skilled in the art that the knee point coercive force of samarium cobalt magnetic steel needs to be above 15kOe and the coercive force Hcj needs to be above 25kOe to be able to be used normally, so that the magnetic performance is the worst. The method is mainly characterized in that a zirconium-rich flaky phase is formed in the heat treatment process, and becomes a channel for diffusing copper and samarium elements, the more copper elements are in a cell wall phase, the higher the coercivity of the magnet is, the zirconium elements are absent, the coercivity of the product is greatly reduced, and finally the product cannot be normally used.
The steel ingot A in the comparative example 3 has the same raw materials as the steel ingot B, but different content components, and the prepared product has higher coercivity, lower remanence and poorer squareness compared with the test result of the example 1, mainly because only samarium, cobalt and iron are contained in the components of the steel ingot B in the example 1, the iron and the cobalt can ensure that the remanence cannot be reduced, the samarium mainly changes the cell wall phase component of the main alloy (namely the steel ingot A), the addition of copper reduces the area of poor copper of the grain boundary of the main alloy (namely the steel ingot A), increases the coercivity of a knee point, and the steel ingot B in the comparative example 3 contains zirconium component, so that a zirconium-rich lamellar phase is easy to form, and the coercivity of the product is higher.
The first additive and/or the second additive are not added in the powder preparation process in comparative examples 4, 5 and 6, so that the magnetic properties of the final product are higher than those of the product in example 1, the remanence and squareness are poorer, and the remanence of the product prepared in comparative example 6 is lowest, mainly because the first additive can reduce powder agglomeration, improve coarse powder mixing uniformity, improve air-flow grinding powder preparation efficiency, reduce the oxidation speed of the fine powder, and the first additive is not used, so that the particle size distribution of the powder is uneven, rare earth is oxidized more, and the product performance is influenced; and the second additive can improve the mixing uniformity of the fine powder, reduce the friction of powder particles, improve the magnetization orientation degree and improve the remanence of the product, and the non-uniform distribution of the powder particles can be caused by not using the second additive, so that the copper-deficient area is increased, and the knee point coercive force is reduced.
The number of equipment and the scale of processing described herein are intended to simplify the description of the present invention. Applications, modifications and variations of the present invention will be readily apparent to those skilled in the art.
Although embodiments of the present invention have been disclosed above, it is not limited to the details and embodiments shown, it is well suited to various fields of use for which the invention is suited, and further modifications may be readily made by one skilled in the art, and the invention is therefore not to be limited to the particular details and examples shown and described herein, without departing from the general concepts defined by the claims and the equivalents thereof.

Claims (8)

1. The preparation method of the samarium cobalt magnetic steel is characterized by comprising the following steps of: respectively preparing steel ingots A and B with different components, mixing and crushing the steel ingots A and B, pulverizing, compacting, sintering, solid-dissolving, and tempering to obtain samarium cobalt magnetic steel, wherein the steel ingot A is prepared from the following ingredients in percentage by mass: 23-28% of Sm, 14-19% of Fe, 5-7% of Cu, 2-3% of Zr and the balance of Co, and the ingredients for preparing the steel ingot B comprise the following components in percentage by mass: 25-30% of Sm, 16-21% of Fe, 4-6% of Cu and the balance of Co, wherein when the steel ingot A and the steel ingot B are mixed and crushed, the mass percentage of the steel ingot A is 80-90%.
2. The method for preparing samarium cobalt magnetic steel according to claim 1, wherein the thickness of each of the steel ingot A and the steel ingot B is 10-20 mm.
3. The method for preparing samarium cobalt magnetic steel according to claim 1, wherein argon is used for protection in the crushing process, and the particle size of coarse particles formed after crushing is smaller than 4mm.
4. The method for preparing samarium cobalt magnetic steel according to claim 1, wherein the specific steps of powder preparation are as follows:
step one, mixing and crushing a steel ingot A and a steel ingot B to form coarse particles, and performing medium crushing to obtain powder with the particle size smaller than 200 mu m;
adding a first additive accounting for 0.01-0.015% of the mass of the powder into the powder, mixing for 1-2 h by using a three-dimensional powder mixer, and standing for 2-4 h, wherein the first additive is mixed liquid of n-hexane and methyl decanoate in a mass ratio of 4:1;
and thirdly, continuing to perform air flow grinding to prepare powder, adding 2000-5000 ppm of dry oxygen, adding a second additive accounting for 0.01-0.015% of the mass of the fine powder into the prepared fine powder, and mixing for 2-3 hours by using a three-dimensional powder mixer to obtain uniformly mixed samarium cobalt alloy powder, wherein the second additive is stearic acid and polyethylene glycol mixed solution with a mass ratio of 3:1.
5. The method for preparing samarium cobalt magnetic steel according to claim 1, wherein the specific process of press forming is as follows: and pressing the samarium cobalt alloy powder obtained by powder preparation by using a closed low-oxygen press, wherein the oxygen content in the closed low-oxygen press is lower than 500ppm, vacuum packaging, and pressing by using a cold isostatic press to finally obtain a pressed compact, and the pressure of the cold isostatic press is 250MPa.
6. The method for preparing samarium cobalt magnetic steel according to claim 1, wherein the specific processes of sintering, solid solution and tempering heat treatment are as follows: placing the pressed compact in a sintering furnace, preserving heat at 1210 ℃ for 1.5h for sintering treatment, wherein the vacuum degree in the sintering furnace is higher than 2 multiplied by 10 -2 Pa, cooling to 1170 ℃ along with a furnace, carrying out solution treatment, carrying out air cooling to room temperature after heat preservation for 8 hours, then carrying out tempering treatment after heating to 850 ℃, slowly cooling to 400 ℃ along with the furnace after heat preservation for 15 hours, carrying out heat preservation at 400 ℃, and carrying out air cooling to room temperature, thereby finally preparing the samarium cobalt magnetic steel.
7. The method of manufacturing samarium cobalt magnetic steel according to claim 6, characterized in that in the tempering treatment, the cooling rate of slowly cooling to 400 ℃ along with the furnace is less than or equal to 0.7 ℃/min.
8. The method for preparing samarium cobalt magnetic steel according to claim 6, wherein in the tempering treatment, the temperature is kept at 400 ℃ for more than or equal to 1.5 hours.
CN202310492925.1A 2023-05-05 2023-05-05 Preparation method of samarium cobalt magnetic steel Pending CN116631758A (en)

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