CN115621030A - Method for synchronously preparing high-performance samarium-iron-nitrogen bonded magnet through magnetic field orientation and hot-press curing molding - Google Patents
Method for synchronously preparing high-performance samarium-iron-nitrogen bonded magnet through magnetic field orientation and hot-press curing molding Download PDFInfo
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- CN115621030A CN115621030A CN202211366989.9A CN202211366989A CN115621030A CN 115621030 A CN115621030 A CN 115621030A CN 202211366989 A CN202211366989 A CN 202211366989A CN 115621030 A CN115621030 A CN 115621030A
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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
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- 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
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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
Abstract
The invention discloses a method for synchronously preparing a high-performance samarium-iron-nitrogen bonded magnet by magnetic field orientation and hot-press curing molding, which comprises the following steps: s1, preparing a surface modification solution; s2, performing magnetic powder surface modification treatment; and S3, carrying out magnetic field orientation and hot-pressing curing on the magnetic powder to obtain the samarium-iron-nitrogen bonded magnet. The method provided by the invention can combine the magnetic field orientation and the hot-pressing curing molding process in the low-oxygen environment to obtain the anisotropic samarium-iron-nitrogen bonded magnet with higher density, better magnetic orientation degree and excellent performance; meanwhile, the method has the advantages of simple process route, low production cost, simplification of the preparation process of the samarium-iron-nitrogen bonded magnet, high economic value and wide application prospect in the field of rare earth permanent magnet materials.
Description
Technical Field
The invention relates to a method for preparing a high-performance samarium iron nitrogen bonded magnet, in particular to a method for synchronously preparing the high-performance samarium iron nitrogen bonded magnet by magnetic field orientation and hot-press curing molding, and belongs to the field of magnetoelectric functional materials.
Background
In 1990, coey and Sun et al used a gas-solid reaction method to introduce N atom into Sm 2 Fe l7 A theoretical chemical formula Sm is obtained in the gaps of the compounds 2 Fe 17 N 3 Has Th 2 Zn 17 The crystal structure of form has excellent intrinsic magnetism, and has attracted researchers' eyes since the past. In terms of intrinsic characteristics, samarium-iron nitrogen compound has a saturation magnetization (1.54T) comparable to neodymium-iron-boron, while a magnetocrystalline anisotropy field (14T) is higher and corrosion resistance is better. More importantly, the Curie temperature of the material is 470 ℃ which is far higher than 312 ℃ of the neodymium iron boron material, and the material becomes a new generation permanent magnetic material with the most development potential. However, as a metastable compound samarium iron nitrogen decomposes to SmN, α -Fe and N at around 600 deg.C 2 Making it extremely difficult to prepare sintered magnets by a high temperature sintering process similar to that used to prepare sintered NdFeB (a)>1000. C) is not suitable for the production of samarium-iron-nitrogen sintered magnets, so its current application is mainly focused on bonded magnets with a high molecular material, particularly, an epoxy resin or the like as a binder.
At present, the preparation process of the thermosetting resin bonded samarium iron nitrogen magnet is divided into multiple steps and mainly comprises the following steps: (1) Respectively pretreating magnetic powder in a solution containing a coupling agent and a bonding agent; (2) Pressing the dried pretreated magnetic powder into a blank; (3) Then the obtained blank is cured at a certain temperature; (4) And magnetizing the cured bonded magnet to obtain the final anisotropic magnet.
For example, CN102982961B discloses a method for preparing anisotropic bonded magnet by pressure-maintaining curing technology, which comprises the following steps of mixing anisotropic magnetic powder, thermosetting binder such as epoxy resin, coupling agent, lubricant and the like uniformly to prepare composite magnetic powder, and then carrying out orientation, compression molding and pressure curing treatment to obtain bonded magnet, wherein the basic process flow is as follows: mixing the magnetic powder with a binder and an additive to obtain composite magnetic powder → orienting magnetic field → molding/warm-pressing molding → demagnetizing → curing → antiseptic treatment → performance detection. The method is to mold and orient at room temperature, and under the action of pressure, the friction force among magnetic powder is large, so that the magnetic powder is difficult to rotate along with a magnetic field, and the large orientation degree is not high.
The patent CN110767403A discloses a warm compaction forming bonding magnet and a preparation method thereof, wherein the preparation method comprises the steps of master alloy smelting, heat treatment, HDDR treatment, glue mixing, powder mixing, pre-pressing forming, orientation forming, curing and the like, the heat conduction capability of a pre-pressing blank is enhanced by adding a composite heat conduction agent, so that the conversion temperature of the added epoxy resin can be reached in a very short time, the powder is in a uniform viscous state epoxy resin, powder particles are orderly arranged when orientation is facilitated, and the improvement of the performance of the magnet is facilitated. The invention provides a technology for carrying out magnetic orientation on magnetic powder in a viscous epoxy resin state, but the steps from the powder state to the block form are more, and the synchronous implementation of the pre-pressing forming, the powder orientation and the magnet curing process cannot be realized. In actual production, manpower cost, equipment cost and production cost are inevitably increased greatly, and the requirement of maximizing income cannot be met. However, the problem of oxidation prevention of magnetic powder, which is extremely important for the final performance of the magnet, has not been sufficiently addressed in the present invention.
And patent CN100568410C discloses a warm-pressing bonding permanent magnet material and a preparation method thereof, in the method, a composite adhesive is mixed with permanent magnet powder, the powder is pressed and molded under certain pressure and temperature, and the warm-pressing bonding permanent magnet material is obtained after magnetization. Although the patent adopts the warm-pressing technology to combine the original pressing and curing processes into a warm-pressing forming process, the used magnetic powder is not subjected to magnetic field orientation before pressing, the magnetic orientation degree of the obtained magnet is not high, the magnetic performance advantage of the original magnetic powder cannot be fully exerted, and the obtained bonded magnet has low residual magnetism and low performance.
Based on the above analysis, although the existing patents have a certain driving effect on the preparation and industrial application of samarium-iron-nitrogen bonded magnets, the existing patents still have many defects, such as:
(1) because the samarium iron nitrogen powder with fine particles is extremely easy to oxidize, and the existence of oxides can greatly influence the final performance of the magnet, the problem of oxidation resistance of the powder needs to be paid particular attention when the magnetic powder is pretreated and heated, and the powder is prevented from contacting with air as much as possible;
(2) the orientation degree of the magnetic powder under the magnetic field is the key influencing the performance of the anisotropic samarium-iron-nitrogen bonded magnet, some of the existing common methods do not adopt magnetic field orientation, and some of the techniques adopting the magnetic field orientation are pressed into a green body at room temperature, so that the magnetic powder rotation resistance is increased without a liquid or low-viscosity medium environment around the magnetic powder, and the orientation degree is greatly reduced while the density of the magnet is improved by increasing the pressure;
(3) because the preparation processes of the prior epoxy resin bonded samarium iron nitrogen magnet are more, if two or more steps can be combined into a whole, the preparation process of the magnet is greatly simplified, and the demolding from the magnetic powder filling mold to the bonded magnet must be completed within 1 minute, so that the method has the value of batch production;
(4) the magnet prepared by the prior art is directly subjected to hot-pressing solidification and demoulding or is subjected to demoulding after the temperature of a mould is naturally cooled, the size of the magnet is deformed due to the fact that the thermosetting resin is kept near a softening temperature point in the direct hot-demoulding process, and the preparation process is prolonged and the production efficiency is greatly reduced due to the natural cooling.
Disclosure of Invention
In order to solve the defects of the prior art, the invention provides a method for synchronously preparing a high-performance samarium-iron-nitrogen bonded magnet by magnetic field orientation and hot press curing molding, which aims to solve the problems that powder is easy to oxidize, a blank is pressed by magnetic orientation at room temperature to cause low magnetic powder orientation degree, and the preparation process is long due to multiple processes from orientation pressing to curing in the preparation process of the conventional thermosetting resin samarium-iron-nitrogen bonded magnet.
In order to solve the technical problems, the invention adopts the technical scheme that: a method for synchronously preparing a high-performance samarium-iron-nitrogen bonded magnet by magnetic field orientation and hot-press curing molding comprises the following steps:
s1, preparing a surface modification solution;
s2, performing magnetic powder surface modification treatment;
and S3, carrying out magnetic field orientation and hot-pressing solidification on the magnetic powder to obtain the samarium-iron-nitrogen bonded magnet.
Preferably, the specific process of step S1 is:
preparation of surface modification solution: respectively weighing a proper amount of coupling agent and thermosetting resin powder, and respectively adding the coupling agent and the thermosetting resin powder into a container filled with acetone and stirring until the solid is completely dissolved.
Preferably, in the step S1, the coupling agent is a silane coupling agent or a titanate coupling agent, and the dosage of the coupling agent is 0.05-2% of the mass of the magnetic powder;
the thermosetting resin adhesive is one of epoxy resin, phenolic resin, urea resin and polyimide, and the dosage of the thermosetting resin adhesive is 1-6% of the mass of the magnetic powder.
Preferably, in step S1, the curing agent includes aliphatic diamine and polyamine, aromatic polyamine, acid anhydride and boron trifluoride; accelerators include DMP-30, EP-184, triethanolamine; the thermosetting resin: curing agent: the proportion of the accelerator is 100:3:3.
preferably, step S2 includes the steps of:
placing anisotropic samarium iron nitrogen magnetic powder in an acetone solution containing a coupling agent and a thermosetting resin adhesive in a glove box protected by inert gas, and stirring at room temperature until the acetone solution volatilizes, wherein the adding amount of the coupling agent and the thermosetting resin in the acetone solution is respectively 0.05-2% and 1-6% of the mass of the samarium iron nitrogen magnetic powder;
drying the magnetic powder at room temperature in an environment with the oxygen content controlled to be less than 100ppm, crushing and screening the dried magnetic powder, wherein the surface of the magnetic powder is coated with a thermosetting resin adhesive, and a coupling agent is arranged between the magnetic powder and the thermosetting resin adhesive to promote the adhesion effect.
Preferably, the specific process of step S2 is:
weighing a certain amount of samarium iron nitrogen magnetic powder in a glove box with controlled oxygen content, pouring the samarium iron nitrogen magnetic powder into an acetone solution containing a coupling agent, stirring for 10min-30min, then adding the acetone solution containing thermosetting resin powder into the mixed solution, and continuously stirring for 30min-60min to uniformly mix the magnetic powder, the coupling agent and the thermosetting resin;
and (2) placing the magnetic powder containing a small amount of solvent in a high vacuum drying oven for drying at normal temperature, placing the dried part of the agglomerated magnetic powder in a three-dimensional mixer filled with inert atmosphere for rotary crushing, and then screening by using a 100-500-mesh screen, thus obtaining the samarium-iron-nitrogen magnetic powder with low oxygen content, the surface of which is coated with thermosetting resin, wherein the coupling agent is arranged between the magnetic powder and the thermosetting resin glue to promote the coating effect.
Preferably, step S3 includes the steps of:
placing the powder treated by the coupling agent and the epoxy resin in a heating mould made of a non-magnetic steel material, and orienting the powder in a strong magnetic field; meanwhile, the powder is pressed and formed at a certain temperature and under a certain pressure, and finally the anisotropic samarium-iron-nitrogen bonded magnet with higher performance is obtained.
Preferably, the specific process of step S3 is:
in a glove box with controlled oxygen content, filling the magnetic powder with the coated surface obtained in the step S2 into a non-magnetic steel mold with a built-in pipeline with two functions of heating and cooling, and placing the non-magnetic steel mold in a magnetic field with certain intensity to orient the magnetic powder;
and during magnetic field orientation, heating the mold through a heating pipeline arranged in the non-magnetic steel mold, further heating powder in the mold, controlling the temperature of a flowing medium of the heating pipeline to be 5-10 ℃ higher than the softening point temperature of the thermosetting resin, immediately applying 50MPa-1.5GPa pressure to bond the magnetic powder into blocks, immediately cooling the bonded blocks through a cold water pipeline arranged in the non-magnetic steel mold to cure and mold the thermosetting resin, applying a reverse magnetic field to demagnetize and demolding, and thus obtaining the high-performance anisotropic samarium iron nitrogen bonded magnet with higher magnetic orientation degree and density.
The magnetizing/demagnetizing field generating source, the mold heating and cooling system and the pressure system in the steps are controlled by a PLC (programmable logic controller) to realize mutual connection and linkage. The button is adopted for centralized control, under the premise of preset process parameters such as magnetic field size, heating temperature, pressure size, pressure maintaining time and the like, one key can realize simultaneous operation of magnetic field orientation, heating medium introduction and pressurization, and simultaneously one key can realize simultaneous operation of demagnetization of a magnet, cooling medium introduction and demolding.
Preferably, in the glove box with controlled oxygen content, the oxygen content is 0.5-100ppm; the average particle diameter of the samarium iron nitrogen magnetic powder is 1 μm to 10 μm, preferably 2 μm.
Preferably, the applied magnetic field is a direct current stabilization magnetic field, and the magnitude of the orientation magnetic field is not less than 1.5T, and preferably a large magnetic field exceeding 2.0T;
in the non-magnetic steel die, a heating pipeline of the non-magnetic steel die is filled with a hot oil medium, a cooling pipeline of the non-magnetic steel die is filled with a cooling water medium, and the two media are circulated by an external pump.
The beneficial effects of the invention are mainly embodied in the following aspects:
(1) The non-magnetic steel die with built-in heating and cooling circulation pipelines can instantly switch between heating and cooling of the die, and can realize heating softening, fluidity improvement, high orientation degree and rapid cooling for solidification and shaping by taking thermosetting resin as a binder;
(2) The oxygen content control of the operating environment is realized through the protection of inert gas in the two processes of the thermosetting resin-coated samarium-iron-nitrogen magnetic powder and the magnetic field orientation-heating curing, the oxidation degree of the obtained powder is greatly reduced, and the final performance of the obtained magnet is improved from the source;
(3) The computer system is controlled and linked to realize synchronous operation of heating to control temperature, magnetic field orientation and pressing, so that time is saved, the production flow of the samarium-iron-nitrogen bonded magnet is greatly simplified, the production cost is reduced, and higher economic value is created; meanwhile, the synchronous operation enables the magnetic powder to rotate along with the orientation magnetic field in the low-viscosity thermosetting resin viscous state environment, so that the rotation resistance is greatly reduced, and in addition, the large magnetic field is applied, the orientation degree of the magnetic powder is greatly improved, and the performance of the bonded magnet is improved.
The method provided by the invention can combine the magnetic field orientation and the hot-pressing curing molding process in the low-oxygen environment to obtain the anisotropic samarium-iron-nitrogen bonded magnet with higher density, better magnetic orientation degree and excellent performance; meanwhile, the method has the advantages of simple process route, low production cost, simplification of the preparation process of the samarium-iron-nitrogen bonded magnet, high economic value and wide application prospect in the field of rare earth permanent magnet materials.
Detailed Description
The present invention will be described in further detail with reference to specific examples.
Example 1:
in a glove box with the oxygen content controlled to be less than 20ppm, 20g of samarium iron nitrogen oxide magnetic powder, 0.2g of KH550 silane coupling agent and 0.4g of epoxy resin adhesive powder are respectively weighed. Respectively adding KH550 silane coupling agent and epoxy resin powder into 60mL acetone solution for dissolving, then pouring the magnetic powder into the acetone solution containing KH550 silane coupling agent and stirring for 30min, then adding the acetone solution containing epoxy resin and stirring for 30min, finally evaporating the solvent at 58 ℃ and drying the magnetic powder in a low-oxygen environment at room temperature to obtain the low-oxygen epoxy resin coated powder.
Weighing 6g of coated magnetic powder in a glove box with the controlled oxygen content of less than 100ppm, filling the coated magnetic powder in a preheated mold, setting an oriented magnetic field to be 1.8T, heating the temperature of a mold cavity of the mold to 152 ℃ through a hot oil pipeline arranged in the mold, setting the pressure of 1.2 GPa, and simultaneously operating magnetic field orientation, heating medium introduction and pressurization by starting one key under the control of a PLC (programmable logic controller), so that the magnetic powder in the mold and softened epoxy resin are rapidly pressurized and bonded into blocks; and setting a demagnetizing field of 1.0T, starting by one key under the control of the PLC to simultaneously apply the demagnetizing field, feed cooling water medium and demould, immediately realizing that the cold water pipeline arranged in the die rapidly cools the bonded block to solidify and mold the epoxy resin coated powder, and applying a reverse magnetic field to demagnetize and demould, thereby obtaining the anisotropic samarium-iron-nitrogen bonded magnet. Magnet density of 5.82g/cm by volume method 3 Through a permanent magnetic property measuring instrument, the remanence of the obtained magnet is 8.886 kGs, the intrinsic coercive force is 9.562kOe, and the maximum magnetic energy product is 121.6kJ/m 3 。
Example 2:
in a glove box with the oxygen content controlled to be less than 20ppm, 20g of samarium iron nitrogen oxide magnetic powder, 0.2g of KH550 silane coupling agent and 1.2g of phenolic resin adhesive powder are respectively weighed. Respectively adding KH550 and phenolic resin powder into 60mL of acetone solution for dissolving, then pouring the magnetic powder into the acetone solution containing KH550 for stirring for 30min, then adding the acetone solution containing phenolic resin into the acetone solution containing phenolic resin for stirring for 30min, finally evaporating the solvent at 58 ℃ and drying the powder at room temperature in a low-oxygen environment to obtain the low-oxygen phenolic resin coated powder.
Weighing 6g of coated magnetic powder in a glove box with the controlled oxygen content of less than 100ppm, filling the coated magnetic powder in a preheated mold, setting an oriented magnetic field to be 2.0T, heating the mold cavity temperature of the mold to 125 ℃ through a hot oil pipeline arranged in the mold, setting the pressure of 1.0 GPa, and simultaneously operating magnetic field orientation, heating medium introduction and pressurization by starting one key under the control of a PLC (programmable logic controller), so that the magnetic powder in the mold and softened phenolic resin are rapidly pressurized and bonded into blocks; and setting a demagnetizing field of 1.0T, starting by one key under the control of the PLC to apply the demagnetizing field, introducing a cooling water medium and demoulding at the same time, immediately realizing the rapid cooling of the bonding block by the cold water pipeline arranged in the mould to solidify and form the phenolic resin coated powder, applying a reverse magnetic field to demagnetize and demoulding, thereby obtaining the anisotropic samarium iron nitrogen bonded magnet. Magnet density of 5.58g/cm by volume method 3 Through a permanent magnet magnetic property measuring instrument, the residual magnetism of the magnet obtained through testing is 8.686 kGs, the intrinsic coercive force is 9.479kOe, and the maximum magnetic energy product is 119.6kJ/m 3 。
Example 3:
in a glove box with the oxygen content controlled to be less than 20ppm, 20g of samarium iron oxide nitride magnetic powder, 0.2g of titanate coupling agent and 1.2g of epoxy resin adhesive powder are respectively weighed. Respectively adding titanate coupling agent and epoxy resin powder into 60mL of acetone solution for dissolving, then pouring the magnetic powder into the acetone solution containing KH550 for stirring for 30min, then adding the acetone solution containing epoxy resin into the acetone solution containing KH550 for stirring for 30min, finally evaporating the solvent at 58 ℃ and drying the powder at room temperature in a low-oxygen environment to obtain the low-oxygen epoxy resin coated powder.
Weighing 6g of coated magnetic powder in a glove box with the oxygen content controlled to be less than 100ppm, filling the coated magnetic powder in a preheated mold, setting an oriented magnetic field to be 2.0T, heating the temperature of a mold cavity of the mold to 155 ℃ through a hot oil pipeline arranged in the mold, setting the pressure to be 1.1 GPa, and starting one key to simultaneously operate magnetic field orientation, heating medium introduction and pressurization under the control of a PLC (programmable logic controller), so that the magnetic powder in the mold and softened epoxy resin are rapidly pressurized and bonded into blocks; and setting a demagnetizing field of 1.0T, starting by one key under the control of the PLC to simultaneously apply the demagnetizing field, feed cooling water medium and demould, immediately realizing that the cold water pipeline arranged in the die rapidly cools the bonded block to solidify and mold the epoxy resin coated powder, and applying a reverse magnetic field to demagnetize and demould, thereby obtaining the anisotropic samarium-iron-nitrogen bonded magnet. Magnet density by volume method of 5.79g/cm 3 Through a permanent magnetic property measuring instrument, the residual magnetism of the obtained magnet is 8.785 kGs, the intrinsic coercive force is 9.575kOe, and the maximum magnetic energy product is 120.7kJ/m 3 。
It can be seen from the above examples 1-3 that the remanence, the coercive force and the maximum energy product of the samarium-iron-nitrogen bonded magnet prepared by the method of the invention all reach high levels. The degree of oxidation of the magnetic powder in the preparation process has great influence on the coercive force of the bonded magnet, the degree of orientation of the magnetic powder also determines the residual magnetism and the maximum energy product of the magnet, the coercive force of the samarium-iron-nitrogen bonded magnet prepared by the method reaches over 9kOe, and the maximum energy product also reaches 120kJ/m 3 The method provided by the invention is fully favorable for reducing the oxidation degree of magnetic powder, improving the orientation degree of the magnet and improving the density of the magnet. Meanwhile, the automation and continuity of the magnet preparation process can greatly increase the production efficiency and yield of the bonded magnet, and the maximization of the production efficiency is facilitated.
The above embodiments are not intended to limit the present invention, and the present invention is not limited to the above examples, and variations, modifications, additions and substitutions which may be made by those skilled in the art within the technical scope of the present invention are also within the protective scope of the present invention.
Claims (10)
1. The utility model provides a method of magnetic field orientation and hot-pressing solidification shaping preparation high performance samarium iron nitrogen bonding magnet in step which characterized in that: the method comprises the following steps:
s1, preparing a surface modification solution;
s2, performing magnetic powder surface modification treatment;
and S3, carrying out magnetic field orientation and hot-pressing curing on the magnetic powder to obtain the samarium-iron-nitrogen bonded magnet.
2. The method for synchronously preparing the high-performance samarium-iron-nitrogen bonded magnet by adopting magnetic field orientation and hot-press curing molding according to claim 1, characterized in that: the specific process of the step S1 is as follows:
preparation of surface modification solution: respectively weighing a proper amount of coupling agent and thermosetting resin powder containing curing agent and accelerating agent, respectively adding the coupling agent and the thermosetting resin powder into a container filled with acetone, and stirring until the solid is completely dissolved.
3. The method for synchronously preparing the high-performance samarium-iron-nitrogen bonded magnet by adopting magnetic field orientation and hot-press curing molding according to claim 2, characterized in that: in the step S1, the coupling agent is a silane coupling agent or a titanate coupling agent, and the dosage of the coupling agent is 0.05-2% of the mass of the magnetic powder;
the thermosetting resin adhesive is one of epoxy resin, phenolic resin, urea resin and polyimide, and the dosage of the thermosetting resin adhesive is 1-6% of the mass of the magnetic powder.
4. The method for synchronously preparing the high-performance samarium-iron-nitrogen bonded magnet by adopting magnetic field orientation and hot-press curing molding according to claim 2, characterized in that: in the step S1, the curing agent comprises aliphatic diamine and polyamine, aromatic polyamine, acid anhydride and boron trifluoride; accelerators include DMP-30,EP-184, triethanolamine; the thermosetting resin: curing agent: the proportion of the accelerator is 100:3:3.
5. the method for synchronously preparing the high-performance samarium-iron-nitrogen bonded magnet by magnetic field orientation and hot-press curing molding according to claim 1, characterized in that: the step S2 includes the steps of:
placing anisotropic samarium iron nitrogen magnetic powder in an acetone solution containing a coupling agent and a thermosetting resin adhesive in a glove box protected by inert gas, and stirring at room temperature until the acetone solution volatilizes, wherein the adding amount of the coupling agent and the thermosetting resin in the acetone solution is respectively 0.05-2% and 1-6% of the mass of the samarium iron nitrogen magnetic powder;
drying the magnetic powder at room temperature in an environment with the oxygen content controlled to be less than 100ppm, crushing and screening the dried magnetic powder, wherein the surface of the magnetic powder is coated with a thermosetting resin adhesive, and a coupling agent is arranged between the magnetic powder and the thermosetting resin adhesive to promote the adhesion effect.
6. The method for synchronously preparing the high-performance samarium-iron-nitrogen bonded magnet by adopting magnetic field orientation and hot-press curing molding according to claim 5, characterized in that: the specific process of the step S2 is as follows:
weighing a certain amount of samarium iron nitrogen magnetic powder in a glove box with controlled oxygen content, pouring the samarium iron nitrogen magnetic powder into an acetone solution containing a coupling agent, stirring for 10min-30min, then adding the acetone solution containing thermosetting resin powder into the mixed solution, and continuously stirring for 30min-60min to uniformly mix the magnetic powder, the coupling agent and the thermosetting resin;
and (2) placing the magnetic powder containing a small amount of solvent in a high vacuum drying oven for drying at normal temperature, placing the dried part of the agglomerated magnetic powder in a three-dimensional mixer filled with inert atmosphere for rotary crushing, and then screening by using a 100-500-mesh screen, thus obtaining the samarium-iron-nitrogen magnetic powder with low oxygen content, the surface of which is coated with thermosetting resin, wherein the coupling agent is arranged between the magnetic powder and the thermosetting resin glue to promote the coating effect.
7. The method for synchronously preparing the high-performance samarium-iron-nitrogen bonded magnet by magnetic field orientation and hot-press curing molding according to claim 1, characterized in that: the step S3 includes the steps of:
placing the powder treated by the coupling agent and the epoxy resin in a heating mould made of a non-magnetic steel material, and orienting the powder in a strong magnetic field; meanwhile, the powder is pressed and formed at a certain temperature and under a certain pressure, and finally the anisotropic samarium-iron-nitrogen bonded magnet with higher performance is obtained.
8. The method for synchronously preparing the high-performance samarium-iron-nitrogen bonded magnet by adopting magnetic field orientation and hot-press curing molding according to claim 7, characterized in that: the specific process of the step S3 is as follows:
in a glove box with controlled oxygen content, filling the magnetic powder with the coated surface obtained in the step S2 into a non-magnetic steel mold with a built-in pipeline with two functions of heating and cooling, and placing the non-magnetic steel mold in a magnetic field with certain strength to perform magnetic field orientation on the magnetic powder;
and heating the die through a heating pipeline arranged in the non-magnetic steel die while orienting the magnetic field, further heating the powder in the die, controlling the temperature of a flowing medium of the heating pipeline to be 5-10 ℃ higher than the softening point temperature of the thermosetting resin, immediately applying 50MPa-1.5GPa pressure to bond the magnetic powder into a block, immediately quickly cooling the bonded block through a cold water pipeline arranged in the non-magnetic steel die to cure and mold the thermosetting resin, applying a reverse magnetic field to demagnetize and demould, and thus obtaining the high-performance anisotropic samarium iron nitrogen bonded magnet with higher magnetic orientation degree and density.
9. The method for synchronously preparing the high-performance samarium-iron-nitrogen bonded magnet by adopting the magnetic field orientation and the hot-press curing molding according to claim 6 or 8, which is characterized in that: in the glove box with the controlled oxygen content, the oxygen content is 0.5-100ppm; the average grain diameter of samarium iron nitrogen magnetic powder is 1-10 μm.
10. The method for synchronously preparing the high-performance samarium-iron-nitrogen bonded magnet by adopting magnetic field orientation and hot-press curing molding according to claim 8, characterized in that: the applied magnetic field is a direct-current stable magnetic field, and the size of the orientation magnetic field is not less than 1.5T;
in the non-magnetic steel die, a heating pipeline of the non-magnetic steel die is fed with hot oil medium, a cooling pipeline of the non-magnetic steel die is fed with cooling water medium, and the two media are circulated by an external pump.
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| CN (1) | CN115621030A (en) |
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2022
- 2022-11-03 CN CN202211366989.9A patent/CN115621030A/en active Pending
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