CN112582123B - Preparation method of sintered samarium-cobalt magnet with low temperature coefficient and high use temperature - Google Patents
Preparation method of sintered samarium-cobalt magnet with low temperature coefficient and high use temperature Download PDFInfo
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- 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
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- B22F1/10—Metallic powder containing lubricating or binding agents; Metallic powder containing organic material
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- B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
- B22F3/02—Compacting only
- B22F3/04—Compacting only by applying fluid pressure, e.g. by cold isostatic pressing [CIP]
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- B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
- B22F3/10—Sintering only
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- B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
- B22F3/24—After-treatment of workpieces or articles
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- 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
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- 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
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- B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
- B22F3/24—After-treatment of workpieces or articles
- B22F2003/248—Thermal after-treatment
Abstract
The invention discloses a preparation method of a sintered samarium cobalt magnet with low temperature coefficient and high use temperature, which comprises the following steps: 1) Preparing ingots a and b; 2) Preparing powder; 3) Mixing the powder; 4) Magnetic field forming and isostatic pressing; 5) Sintering, solid solution and aging treatment. According to the invention, an alloy ingot a (high-temperature magnet) and an alloy ingot b (low-temperature coefficient magnet) are pulverized according to a proper proportion, then the powders are mixed, pressed and subjected to heat treatment, and the prepared sintered samarium-cobalt magnet has the dual characteristics of low-temperature coefficient and high service temperature.
Description
Technical Field
The present invention relates to a magnetic material. More specifically, the invention relates to a preparation method of a sintered samarium cobalt magnet with low temperature coefficient and high use temperature.
Background
As a second generation rare earth permanent magnet material 2, 17 type samarium cobalt permanent magnet material, because of its excellent high temperature stability, corrosion resistance and oxidation resistance, and widely used in the fields such as rail transit, satellite communication and aerospace, 2.
And 2. The analysis on the components shows that the high-performance magnet contains higher Fe content, the weight percentage is about 13-22%, and the high-performance magnet has higher magnetic energy product at normal temperature but poorer high-temperature performance; the low-temperature coefficient magnet is characterized in that Dy and Gd are added into the magnet to reduce the temperature coefficient of the magnet, and the temperature coefficient of the magnet is lower at 0-200 ℃; the high-use-temperature magnet contains high Cu element, co element and low Fe content, wherein the weight percentage of Fe is about 4-8%, the normal-temperature magnetic energy product is not high due to the low Fe content, the weight percentage of Cu is about 5-8%, the Cu element mainly enters a cell wall, the high Cu content can increase the anisotropy of a main phase and the cell wall phase, and therefore the coercive force of the magnet is increased, the coercive force of the high-temperature magnet at normal temperature is high, the Curie temperature of the magnet can be increased due to the high Co content, the maximum magnetic energy product of the high-temperature magnet is high at 500 ℃, and the comprehensive magnetic performance is good. The magnet has higher normal temperature magnetic performance, does not necessarily represent that the high temperature magnetic performance is also high, if the prepared magnet has higher normal temperature performance and stable performance at high temperature, the use potential of the samarium cobalt material can be exerted to a great extent, and the comprehensive national strength level of China can be promoted to be improved by a large step.
From the analysis of the components of samarium cobalt materials, it can be known that the Fe content of a high-performance samarium cobalt magnet and a high-use-temperature magnet is 8-13% of a vacancy, and for a low-temperature coefficient samarium cobalt magnet, the Fe content is just in the range, so how to combine the components of the high-use-temperature magnet and the characteristics of the low-temperature coefficient magnet to prepare the low-temperature coefficient high-use-temperature sintered samarium cobalt magnet is a technical problem to be solved urgently.
Disclosure of Invention
It is an object of the present invention to address at least the above problems and to provide at least the advantages described hereinafter.
The invention also aims to provide a preparation method of the sintered samarium cobalt magnet with low temperature coefficient and high use temperature, which comprises the steps of preparing powder from an alloy ingot a (high-temperature magnet) and an alloy ingot b (low-temperature coefficient magnet) according to a proper proportion, mixing the powder, pressing and carrying out heat treatment, wherein the prepared sintered samarium cobalt magnet has the dual characteristics of low temperature coefficient and high use temperature.
To achieve these objects and other advantages and in accordance with the purpose of the invention, there is provided a method for producing a low temperature coefficient high use temperature sintered samarium cobalt magnet comprising:
1) The components of the ingot a are Sm:24 to 28%, fe:5 to 8%, zr:2 to 5%, cu: 4-8% and the balance of Co;
the components of the ingot b are Sm:12 to 21%, gd:5 to 10 percent; dy:2 to 5 percent; fe:10 to 15%, zr:2 to 5%, cu: 4-8% and the balance of Co;
burdening according to the components, and then respectively smelting and casting in an inert atmosphere to obtain an ingot a and an ingot b;
2) Mechanically crushing, medium crushing and jet milling the ingot a and the ingot b according to the weight ratio of 1.5-1.5 under the protection of nitrogen to obtain alloy powder;
3) Adding the alloy powder into a lubricant with the total weight of 0.1-0.5 per mill, and mixing for 0.5-3 h to obtain alloy magnetic powder;
4) Weighing the alloy magnetic powder, then performing orientation molding in an open press, wherein the orientation molding magnetic field intensity is 1.2-2T, and then performing cold isostatic pressing, wherein the cold isostatic pressing pressure is 200-300 MPa, so as to prepare a green body;
5) The green body is subjected to heat preservation for 0.5 to 2 hours at the temperature of between 300 and 500 ℃ for exhaust treatment, is heated to between 1200 and 1220 ℃ for heat preservation for 0.5 to 2h for pre-densification treatment, is heated to between 1220 and 1240 ℃ for sintering for 1 to 3 hours for further densification treatment, is cooled to between 1130 and 1180 ℃ for solid solution treatment for 4 to 8 hours, and is quickly air-cooled to room temperature; and then heating to 800-900 ℃, keeping the temperature for 10-40 h, controlling the temperature, cooling to 400 ℃, keeping the temperature for 1-20 h, and cooling to room temperature by air to obtain the sintered samarium-cobalt magnet.
Preferably, the samarium cobalt alloy raw material in the step 1) is smelted and cast under the protection of argon.
Preferably, the thickness of the ingot a and the ingot b in the step 1) is 6mm.
Preferably, the alloy powder in step 2) has a particle size of 3 to 5 μm.
Preferably, the orientation molding magnetic field intensity in the step 4) is 2T, and the cold isostatic pressure is 300MPa.
The sintered samarium-cobalt magnet obtained by the preparation method.
The invention at least comprises the following beneficial effects:
the invention only needs to smelt two kinds of ingots, then the alloy ingot a (high temperature magnet) and the ingot b (low temperature coefficient magnet) are pulverized according to a proper proportion, then the powders are mixed, pressed and heat treated, the magnet with excellent performance can be prepared by regulating and controlling the components and the process, the absolute value of the temperature coefficient of residual magnetism at 25-500 ℃ reaches about 0.03%, the absolute value of the temperature coefficient of coercive force reaches about 0.2%, and the magnetic energy product at 500 ℃ reaches 13 MGOe.
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.
Drawings
FIG. 1 is a flow chart of the preparation method of the present invention.
Detailed Description
The present invention is further described in detail below with reference to examples to enable those skilled in the art to practice the invention with reference 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 is to be noted that the experimental methods described in the following embodiments are all conventional methods unless otherwise specified, and the reagents and materials are commercially available unless otherwise specified.
The preparation method of the sintered samarium-cobalt magnet with low temperature coefficient and high use temperature comprises the following steps:
1) Preparation of ingots a and b:
the components of the ingot a are Sm:24 to 28%, fe:5 to 8%, zr:2 to 5%, cu: 4-8% and the balance of Co;
the components of the ingot b are Sm:12 to 21%, gd:5 to 10 percent; dy:2 to 5 percent; fe:10 to 15%, zr:2 to 5%, cu: 4-8% and the balance of Co;
the preparation method comprises the following steps of proportioning according to components, smelting and casting respectively in a high-purity inert atmosphere (preferably argon), effectively preventing Sm from volatilizing and ingot casting from oxidizing, smelting in a medium-frequency smelting furnace, and casting in a cold-water copper mould to obtain an ingot casting a and an ingot casting b with the thickness of 6 mm;
2) Preparation of powder:
mechanically crushing and medium crushing the ingot a and the ingot b according to the weight ratio of 1.5-1.5 under the protection of high-purity nitrogen, wherein the crushed granularity is about 100-500 mu m, and performing jet milling to obtain alloy powder with the granularity of 3-5 mu m;
3) Mixing of the powder:
adding lubricant with the total weight of 0.1-0.5 per mill into the alloy powder, and mixing for 0.5-3 h to obtain alloy magnetic powder;
4) Magnetic field forming, isostatic pressing:
weighing the alloy magnetic powder, then performing orientation molding in an open press, wherein the orientation molding magnetic field intensity is 1.2-2T, then performing cold isostatic pressing, and the cold isostatic pressing pressure is 200-300 MPa, so as to prepare a green body;
5) Sintering solid solution and aging treatment:
the green body is subjected to heat preservation for 0.5 to 2 hours at the temperature of between 300 and 500 ℃ for exhaust treatment, is heated to between 1200 and 1220 ℃ for heat preservation for 0.5 to 2 hours for pre-densification treatment, is heated to between 1220 and 1240 ℃ at the heating rate of 1 ℃/min for sintering for 1 to 3 hours for further densification treatment, is cooled to between 1130 and 1180 ℃ for solid solution treatment for 4 to 8 hours, and is quickly air-cooled to room temperature; then heating to 800-900 ℃, keeping the temperature for 10-40 h, cooling to 440 ℃ at the speed of 0.7-1 ℃/min, keeping the temperature for 1-20 h, and cooling to room temperature by air to obtain the sintered samarium-cobalt magnet.
< example 1>
The preparation method of the sintered samarium-cobalt magnet with low temperature coefficient and high use temperature comprises the following steps:
1) The cast ingot a comprises the following components in percentage by weight: sm:26.5%, fe:7.7%, zr:2.4%, cu: 7.2 percent and the balance of Co;
the components of the ingot b are as follows: sm:14.6%, gd:8.3 percent; dy:3.6 percent; fe:13.8%, zr:2.5%, cu: 6.8 percent and the balance of Co;
preparing materials according to the components, then respectively smelting and casting in a high-purity helium atmosphere, wherein the smelting is carried out in a medium-frequency smelting furnace, and the casting is carried out in a cold water copper-cooling mold of a disc, so as to obtain an ingot a and an ingot b with the thickness of 6 mm;
2) Mechanically crushing and crushing the ingot a and the ingot b according to a weight ratio of 1.93 under the protection of high-purity nitrogen, wherein the crushed particle size is 300 mu m, then putting the crushed powder into an airflow mill together for further crushing, and obtaining alloy powder with the particle size of 3.35 mu m after crushing;
3) Adding a lubricant with the total weight of 0.35 per mill into the alloy powder, and mixing for 2 hours to obtain alloy magnetic powder in order to ensure uniform mixing;
4) Weighing the alloy magnetic powder, then performing orientation molding in an open press, wherein the orientation molding magnetic field intensity is 2T, and then performing cold isostatic pressing, wherein the cold isostatic pressing pressure is 300MPa, so as to prepare a green body;
5) Carrying out exhaust treatment on the green body by keeping the temperature of 385 ℃ for 2h, heating to 1203 ℃ for 1h for pre-densification treatment, heating to 1229 ℃ at the heating rate of 1 ℃/min for sintering for 1h for further densification treatment, then cooling to 1175 ℃ for 6h for solution treatment, and rapidly cooling to room temperature by air; and then heating to 830 ℃, preserving the heat for 10 hours, cooling to 440 ℃ at the speed of 0.75 ℃/min, preserving the heat for 10 hours, and cooling to room temperature by air to obtain the sintered samarium-cobalt magnet.
The magnetic performance of the prepared sintered samarium cobalt magnet is as follows: remanence of B at 25 DEG C r =9.3kGs magnetic energy product (BH) max =20.45 MGOe, intrinsic coercive force H cj =32.14kOe; remanence B at 500 deg.C r =7.67kGs magnetic energy product (BH) max =13.15 MGOe, intrinsic coercive force H cj =8.33kOe, wherein the temperature coefficient of remanence is-0.037 percent, and the temperature coefficient of coercivity is-0.156 percent.
< example 2>
The preparation method of the sintered samarium-cobalt magnet with low temperature coefficient and high use temperature comprises the following steps:
1) The cast ingot a comprises the following components in percentage by weight: sm:25.3%, fe:6.8%, zr:3.1%, cu: 6.9 percent and the balance of Co;
the components of the ingot b are as follows: sm:13.7%, gd:7.8 percent; dy:4.7 percent; fe:12.8%, zr:2.3%, cu: 6.8 percent and the balance of Co;
preparing materials according to the components, then respectively smelting and casting in a high-purity helium atmosphere, wherein the smelting is carried out in a medium-frequency smelting furnace, and the casting is carried out in a cold water copper-cooling mold of a disc, so as to obtain an ingot a and an ingot b with the thickness of 6 mm;
2) Mechanically crushing and crushing the ingot a and the ingot b according to a weight ratio of 1.71 under the protection of high-purity nitrogen, wherein the crushed particle size is 360 mu m, then putting the crushed powder into an airflow mill together for further crushing, and obtaining alloy powder with the particle size of 3.8 mu m after crushing;
3) Adding a lubricant with the total weight of 0.24 per mill into the alloy powder, and mixing for 2.5 hours to obtain alloy magnetic powder in order to ensure uniform mixing;
4) Weighing the alloy magnetic powder, then performing orientation molding in an open press, wherein the orientation molding magnetic field intensity is 1.8T, then performing cold isostatic pressing, and the cold isostatic pressing pressure is 260MPa, thus preparing a green body;
5) The green body is subjected to heat preservation at 415 ℃ for 2h for exhaust treatment, heated to 1205 ℃ and subjected to heat preservation for 1h for pre-densification treatment, heated to 1232 ℃ at the heating rate of 1 ℃/min for sintering for 1h for further densification treatment, then cooled to 1185 ℃ for 4h for solid solution treatment, and rapidly air-cooled to room temperature; and then heating to 860 ℃, preserving heat for 10 hours, cooling to 440 ℃ at the speed of 0.8 ℃/min, preserving heat for 6 hours, and cooling to room temperature by air to obtain the sintered samarium-cobalt magnet.
The prepared sintered samarium cobalt magnet has the following magnetic properties: remanence of B at 25 DEG C r =9.35kGs magnetic energy product (BH) max =21.75 MGOe, intrinsic coercivity H cj =37.14kOe; remanence B at 500 deg.C r =7.63kGs magnetic energy product (BH) max =12.75 MGOe, intrinsic coercivity H cj And 8.56kOe, wherein the temperature coefficient of remanence is-0.038%, and the temperature coefficient of coercivity is-0.162%.
< example 3>
The preparation method of the sintered samarium-cobalt magnet with low temperature coefficient and high use temperature comprises the following steps:
1) The cast ingot a comprises the following components in percentage by weight: sm:25.6%, fe:7.1%, zr:2.7%, cu: 7.6 percent, and the balance of Co;
the components of the ingot b are as follows: sm:13.7%, gd:8.5 percent; dy:4.4 percent; fe:13.1%, zr:2.5%, cu: 6.2 percent and the balance of Co;
preparing materials according to the components, then respectively smelting and casting in a high-purity argon atmosphere, wherein the smelting is carried out in a medium-frequency smelting furnace, and the casting is carried out in a cold water-cooled copper mold to obtain an ingot a and an ingot b with the thickness of 6 mm;
2) Mechanically crushing and crushing the ingot a and the ingot b according to a weight ratio of 1.13 under the protection of high-purity nitrogen, wherein the crushed particle size is 260 mu m, then putting the crushed powder into an airflow mill together for further crushing, and obtaining alloy powder with the particle size of 4.5 mu m after crushing;
3) Adding a lubricant with the total weight of 0.44 per mill into the alloy powder, and mixing for 3 hours to obtain alloy magnetic powder in order to ensure uniform mixing;
4) Weighing the alloy magnetic powder, then performing orientation molding in an open press, wherein the magnetic field intensity of the orientation molding is 1.5T, then performing cold isostatic pressing, and the cold isostatic pressing pressure is 240MPa to prepare a green body;
5) Keeping the temperature of the green body at 445 ℃ for 2h for exhaust treatment, heating to 1201 ℃ for 1h for pre-densification treatment, heating to 1231 ℃ at the heating rate of 1 ℃/min for sintering for 1h for further densification treatment, then cooling to 1180 ℃ for 4h for solid solution treatment, and rapidly cooling to room temperature by air cooling; and then heating to 820 ℃, keeping the temperature for 12h, cooling to 440 ℃ at the speed of 0.88 ℃/min, keeping the temperature for 10h, and cooling to room temperature by air to obtain the sintered samarium-cobalt magnet.
The magnetic performance of the prepared sintered samarium cobalt magnet is as follows: remanence of B at 25 DEG C r =9.11kGs magnetic energy product (BH) max =20.14 MGOe, intrinsic coercivity H cj =26.18kOe; remanence B at 500 deg.C r =7.88kGs magnetic energy product (BH) max =13.35 MGOe, intrinsic coercive force H cj =7.13kOe, wherein remanenceThe temperature coefficient is-0.028%, and the coercive force temperature coefficient is-0.153%.
< example 4>
The preparation method of the sintered samarium-cobalt magnet with low temperature coefficient and high use temperature comprises the following steps:
1) The cast ingot a comprises the following components in percentage by weight: sm:24.6%, fe:5.6%, zr:2.2%, cu: 6.2 percent and the balance of Co;
the components of the ingot b are as follows: sm:12.4%, gd:9.6 percent; dy:4.8 percent; fe:12.4%, zr:2.5%, cu: 6.2 percent and the balance of Co;
preparing materials according to the components, then respectively smelting and casting in a high-purity argon atmosphere, wherein the smelting is carried out in a medium-frequency smelting furnace, and the casting is carried out in a cold water-cooled copper mold to obtain an ingot a and an ingot b with the thickness of 6 mm;
2) Mechanically crushing and crushing the ingot a and the ingot b according to the weight ratio of 1.46 under the protection of high-purity nitrogen, wherein the crushed particle size is 380 mu m, then putting the crushed powder into an airflow mill together for further crushing, and obtaining alloy powder with the particle size of 3.8 mu m after crushing;
3) Adding a lubricant with the total weight of 0.37 per mill into the alloy powder, and mixing for 2.5 hours to obtain alloy magnetic powder in order to ensure uniform mixing;
4) Weighing the alloy magnetic powder, then performing orientation molding in an open press, wherein the orientation molding magnetic field intensity is 1.25T, and then performing cold isostatic pressing, wherein the cold isostatic pressing pressure is 220MPa, so as to prepare a green body;
5) Carrying out exhaust treatment on the green body by keeping the temperature of 485 ℃ for 1.5h, heating to 1205 ℃ and keeping the temperature for 1h for pre-densification treatment, heating to 1230 ℃ at the heating rate of 1 ℃/min for further densification treatment by sintering for 1h, then cooling to 1195 ℃ for 5h for solid solution treatment, and rapidly cooling to room temperature by air; and then heating to 850 ℃, keeping the temperature for 15h, cooling to 440 ℃ at the speed of 0.95 ℃/min, keeping the temperature for 10h, and cooling to room temperature by air to obtain the sintered samarium-cobalt magnet.
The prepared sintered samarium cobalt magnet has the following magnetic properties: remanence of B at 25 DEG C r =9.04kGs magnetic energy product (BH) max =19.33 MGOe, intrinsic coercivity H cj =25.18kOe; remanence B at 500 deg.C r =7.78kGs magnetic energy product (BH) max =12.78 MGOe, intrinsic coercive force H cj And =6.74kOe, wherein the temperature coefficient of remanence is-0.029% and the temperature coefficient of coercivity is-0.154%.
< comparative example 1>
As in example 1, ingot a and ingot b were each subjected directly to crushing, molding and heat treatment.
< comparative example 2>
As in example 2, ingot a and ingot b were each subjected directly to crushing, molding and heat treatment.
< comparative example 3>
As in example 3, ingot a and ingot b were each subjected directly to crushing, molding and heat treatment.
< comparative example 4>
As in example 4, ingot a and ingot b were each subjected directly to crushing, molding and heat treatment.
In order to verify the preparation method of sintered samarium cobalt for sintered samarium cobalt with low temperature coefficient and high use temperature in the patent of the present invention, the performance indexes of examples 1 to 4 and comparative examples 1 to 4 are respectively listed in the following table 1. It can be seen that the present invention provides a method of making a sintered samarium cobalt magnet having a low temperature coefficient and a high use temperature that has the dual characteristics of both a low temperature coefficient and a high use temperature (e.g., the magnet made in example 1 has both a high magnetic energy product (BH) at high temperature) max About 13.15MGOe and ingot a magnetic energy product (BH) max About 13.345MGOe, with a low temperature coefficient of remanence-0.037% and a temperature coefficient of coercivity-0.156% comparable to-0.034%, -0.156% for ingot b).
TABLE 1
The number of apparatuses and the scale of the process described herein are intended to simplify the description of the present invention. Applications, modifications and variations of the present invention will be apparent to those skilled in the art.
While embodiments of the invention have been described above, it is not limited to the applications set forth in the description and the embodiments, which are fully applicable to various fields of endeavor for which the invention may be embodied with additional modifications as would be readily apparent to those skilled in the art, and the invention is thus not to be limited to the details given herein and to the examples shown and described without departing from the generic concept as defined by the claims and their equivalents.
Claims (6)
1. A preparation method of a sintered samarium-cobalt magnet with low temperature coefficient and high use temperature is characterized by comprising the following steps:
1) The components of the ingot a are Sm:24 to 28%, fe:5 to 8%, zr:2 to 5%, cu: 4-8% and the balance of Co;
the components of the ingot b are Sm:12 to 21%, gd:5 to 10 percent; dy:2 to 5 percent; fe:10 to 15%, zr:2 to 5%, cu: 4-8% and the balance of Co;
preparing materials according to the components, and then respectively smelting and casting in an inert atmosphere to obtain an ingot a and an ingot b;
2) Mechanically crushing, medium crushing and jet milling the ingot a and the ingot b according to the weight ratio of 1.5-1.5 under the protection of nitrogen to obtain alloy powder;
3) Adding the alloy powder into a lubricant with the total weight of 0.1-0.5 per mill, and mixing for 0.5-3 h to obtain alloy magnetic powder;
4) Weighing the alloy magnetic powder, then performing orientation molding in an open press, wherein the orientation molding magnetic field intensity is 1.2-2T, and then performing cold isostatic pressing, wherein the cold isostatic pressing pressure is 200-300 MPa, so as to prepare a green body;
5) The green body is subjected to heat preservation for 0.5 to 2 hours at the temperature of 300 to 500 ℃ for exhaust treatment, is heated to 1200 to 1220 ℃ for heat preservation for 0.5 to 2 hours for pre-densification treatment, is heated to 1220 to 1240 ℃ for sintering for 1 to 3 hours for further densification treatment, is cooled to 1130 to 1180 ℃ for solid solution treatment for 4 to 8 hours, and is quickly air-cooled to room temperature; and then heating to 800-900 ℃, keeping the temperature for 10-40 h, controlling the temperature, cooling to 400 ℃, keeping the temperature for 1-20 h, and cooling to room temperature by air to obtain the sintered samarium-cobalt magnet.
2. The method of making a low temperature coefficient high use temperature sintered samarium cobalt magnet of claim 1 in which the samarium cobalt alloy starting material of step 1) is melted and cast under argon shield.
3. The method of making a low temperature coefficient high use temperature sintered samarium cobalt magnet of claim 1 wherein the thickness of both ingot a and ingot b of step 1) is 6mm.
4. The method of making a low temperature coefficient high use temperature sintered samarium cobalt magnet of claim 1 wherein the alloy powder particle size of step 2) is 3 to 5 μm.
5. The method of making a low temperature coefficient high use temperature sintered samarium cobalt magnet of claim 1 wherein the orientation forming magnetic field strength of step 4) is 2T and the cold isostatic pressure is 300MPa.
6. A sintered samarium cobalt magnet obtained by the method of any of claims 1 to 5.
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| CN108039258A (en) * | 2017-12-01 | 2018-05-15 | 北京航空航天大学 | A kind of high temperature high-coercive force samarium-cobalt permanent-magnetic material and preparation method |
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| CN105931780A (en) * | 2016-06-27 | 2016-09-07 | 无锡新大力电机有限公司 | Preparation method of samarium-cobalt permanent magnet material |
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| CN108039258A (en) * | 2017-12-01 | 2018-05-15 | 北京航空航天大学 | A kind of high temperature high-coercive force samarium-cobalt permanent-magnetic material and preparation method |
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