CN115763030A - Preparation method of high-performance neodymium iron boron magnetic powder - Google Patents
Preparation method of high-performance neodymium iron boron magnetic powder Download PDFInfo
- Publication number
- CN115763030A CN115763030A CN202211354286.4A CN202211354286A CN115763030A CN 115763030 A CN115763030 A CN 115763030A CN 202211354286 A CN202211354286 A CN 202211354286A CN 115763030 A CN115763030 A CN 115763030A
- Authority
- CN
- China
- Prior art keywords
- magnetic powder
- iron boron
- neodymium iron
- hydrogen
- heat treatment
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Landscapes
- Hard Magnetic Materials (AREA)
Abstract
The invention provides a preparation method of high-performance neodymium iron boron magnetic powder, which comprises the following steps: a) Carrying out homogenization heat treatment on the neodymium iron boron rapid hardening alloy cast sheet; b) Carrying out hydrogen crushing and air flow grinding on the neodymium iron boron quick-setting alloy cast sheet obtained in the step A) to obtain neodymium iron boron magnetic powder; c) Carrying out HDDR treatment on the neodymium iron boron magnetic powder to obtain HDDR magnetic powder; d) Mixing the HDDR magnetic powder with high-melting-point alloy powder to obtain mixed magnetic powder; e) And carrying out at least one-time heat treatment on the mixed magnetic powder to obtain the high-performance neodymium iron boron magnetic powder. The preparation method provided by the invention can be used for preparing the neodymium iron boron magnetic powder with the ideal coating structure, wherein the main phase crystal grains are uniformly coated with the rare earth-rich phase, and the magnetic performance of the magnetic powder and a subsequently prepared magnet is effectively improved.
Description
Technical Field
The invention relates to the technical field of magnetic materials, in particular to a preparation method of high-performance neodymium iron boron magnetic powder.
Background
The requirement of energy-saving reconstruction drives the explosive application of the rare earth permanent magnet motor in the fields of new energy automobiles, wind power, rail transit, industrial robots and the like, and the neodymium iron boron rare earth permanent magnet material becomes an irreplaceable core functional material in the rare earth permanent magnet motor due to the excellent comprehensive magnetic performance of the neodymium iron boron rare earth permanent magnet material. The coercive force is taken as an index for representing the capability of a permanent magnet material for resisting an external reverse magnetic field or other demagnetization effects, and has important significance on the service stability of the permanent magnet material, however, the actual value of the coercive force of the prior neodymium iron boron magnet is still far from the theoretical value of the coercive force, and the improvement of the coercive force of the neodymium iron boron magnet is still the key and difficult point of research in the industry.
Theoretical calculation shows that the exchange coupling length between the neodymium iron boron magnet grains is about 2.1 nanometers, and if the grain boundary is non-magnetic, the grains are isolated and the coercive force is greatly improved when the thickness is exceeded. However, the situation that the distribution of grain boundary phases is discontinuous or the main phase particles are directly connected often exists between adjacent main phase particles of the magnet prepared by the conventional process at present, so that the exchange coupling effect between the main phases is strong, the reverse magnetization process is easy to occur, the reverse magnetization domain is easy to transfer, and finally the coercivity is low. In order to optimize the magnet structure and finally improve the coercive force of the magnet, researchers try to optimize and modify the magnet in various ways such as a fine-grain method, grain boundary reconstruction (grain boundary diffusion, a double-alloy method) and the like, and certain effect is achieved, but corresponding problems also occur, such as the problem of compact density distribution and oxidation caused by the fine-grain method, the problem of remanence reduction caused by the grain boundary reconstruction and the like.
Recent academic circles try to optimize the magnetic powder structure from the powder preparation source so as to prepare a high-coercivity and high-performance magnet on the basis of obtaining the high-performance neodymium iron boron magnetic powder. The neodymium iron boron magnetic powder for anisotropic sintering is industrially prepared by adopting a process of quick-setting casting sheet (SC sheet) + Hydrogen Decrepitation (HD) + Jet Mill (JM), however, the Nd-rich phase on the surface of the neodymium iron boron powder particle prepared by the method is less in coating and irregular in shape at present, so that the shape of a magnet crystal grain after liquid phase sintering is poor, the magnet crystal grain has obvious sharp corners, continuous crystal boundaries are lacked among the crystal grains, the magnetic isolation function of the crystal boundary phase is weak, the improvement of the magnet coercive force is seriously restricted, and the magnetic powder prepared by the method cannot meet the research and development requirements of a high-performance magnet.
In view of this, the method for preparing the high-performance neodymium iron boron magnetic powder is designed, the powder structure is optimized in the powder preparation process, and the prepared neodymium iron boron magnetic powder with regular appearance, small and uniform size and uniform surface coated with the Nd-rich phase has far-reaching significance for improving the coercive force of the neodymium iron boron magnet and promoting the rapid development of the neodymium iron boron industry and the rare earth permanent magnet field.
Disclosure of Invention
The technical problem to be solved by the invention is to provide a preparation method of high-performance neodymium iron boron magnetic powder, and the neodymium iron boron magnetic powder prepared by the method has the advantages of regular appearance, fine and uniform size, uniform surface and rare earth-rich phase coating, so that the neodymium iron boron magnetic powder has higher coercive force.
In view of this, the application provides a method for preparing high-performance neodymium iron boron magnetic powder, including the following steps:
a) Carrying out homogenization heat treatment on the neodymium iron boron rapid hardening alloy casting sheet shown as the formula (I);
b) Carrying out hydrogen crushing and air flow grinding on the neodymium iron boron quick-setting alloy cast sheet obtained in the step A) to obtain neodymium iron boron magnetic powder;
c) Carrying out HDDR treatment on the neodymium iron boron magnetic powder to obtain HDDR magnetic powder;
d) Mixing the HDDR magnetic powder with high-melting-point alloy powder to obtain mixed magnetic powder;
e) Carrying out at least one heat treatment on the mixed magnetic powder to obtain high-performance neodymium iron boron magnetic powder;
RE a T 100-a-b-c B b M c (Ⅰ)；
wherein RE is selected from one or more of Nd, pr, la, ce, dy and Tb;
t is selected from one or more of Fe, co and Ni;
m is selected from one or more of Ga, nb, zr, cu, al, V, ti, mo, si and Mn;
a. b and c respectively represent RE, B and M in percentage by weight of the whole, and the following conditions are met: a is more than or equal to 29.0wt% and less than or equal to 33.5wt%, b is more than or equal to 0.9wt% and less than or equal to 1.1wt%, and c is more than or equal to 0wt% and less than or equal to 3.5wt%.
Preferably, the refractory alloy powder is selected from one or more of Ti, zr, V, nb, ta, hf, W, mo and Fe.
Preferably, the temperature of the homogenization heat treatment is 800-1500 ℃, the heating rate is 5-15 ℃/min, the time is 1-10 h, and the vacuum degree is not less than 1 multiplied by 10 -2 Pa。
Preferably, the hydrogen fragmentation process specifically comprises:
placing the neodymium iron boron rapid hardening alloy casting sheet obtained in the step A) in hydrogen of 100-300 kPa for hydrogen absorption for 0.5-5 h, and after the hydrogen absorption is finished, dehydrogenating for 1-12 h at 200-500 ℃.
Preferably, the particle size of the neodymium iron boron magnetic powder is 1-10 μm.
Preferably, the HDDR processing process specifically comprises:
a heating stage: placing the neodymium iron boron magnetic powder in a hydrogen heat treatment furnace, and heating to 600-1000 ℃ in a vacuum environment;
a hydrogenation disproportionation stage: introducing 10-80 kPa hydrogen into the hydrogen heat treatment furnace, and keeping the temperature and the pressure for 30-240 min;
and (3) a slow dehydrogenation stage: adjusting the hydrogen pressure in the furnace to 1-10 kPa, and continuously keeping the temperature and the pressure for 30-100 min;
and a recombination stage: pumping the furnace to a vacuum degree of not less than 1 × 10 -2 Pa, and keeping the temperature for 20-60 min.
Preferably, the high melting point alloy powder is 1 to 10wt% of the HDDR magnetic powder.
Preferably, the heat treatment is carried out once, the temperature rise speed of the heat treatment is 5-15 ℃/min, the temperature is 500-1000 ℃, and the vacuum degree is not less than 1 multiplied by 10 -2 Pa, the time is 1-10 h.
Preferably, the cooling mode of the heat treatment is air quenching and air cooling.
Preferably, a is more than or equal to 30.0wt% and less than or equal to 32.0wt%, b is more than or equal to 0.9wt% and less than or equal to 1.1wt%, and c is more than or equal to 0.1wt% and less than or equal to 1.0wt%.
The application provides a preparation method of high-performance neodymium iron boron magnetic powder, which comprises the steps of firstly carrying out homogenization heat treatment on a neodymium iron boron quick-setting alloy casting sheet, then carrying out hydrogen crushing and air flow grinding on the obtained alloy casting sheet to obtain neodymium iron boron magnetic powder, then carrying out HDDR treatment on the obtained magnetic powder, and finally mixing the obtained anisotropic HDDR magnetic powder with high-melting-point alloy powder and carrying out heat treatment to obtain the high-performance neodymium iron boron magnetic powder; HDDR treatment is carried out on magnetic powder after jet milling, so that crystal swallow among formed nano-scale crystal grains grows, a rare earth-rich phase is extruded to the periphery of the grains, and component distribution of the rare earth-rich phase evenly coating a main phase crystal grain is formed; and then the high-melting-point alloy and the HDDR magnetic powder are uniformly mixed, so that the rare earth-rich phase extruded around the particles is prevented from being molten to cause the particles to be adhered, the added high-melting-point alloy can inhibit the growth of crystal grains in the subsequent magnetic powder sintering process, and the advantage of fine grains is fully exerted to improve the coercivity. The preparation method of the high-performance magnetic powder provided by the invention can be used for preparing the high-anisotropy HDDR magnetic powder with consistent orientation in batch, optimizing the component distribution of the magnetic powder, improving the coercive force of the magnetic powder, avoiding using heavy rare earth, and being simple and easy to operate and convenient to produce and apply.
Drawings
Fig. 1 is a schematic diagram of the principle of preparing high-performance neodymium iron boron magnetic powder according to the present invention.
Detailed Description
For a further understanding of the present invention, reference will now be made to the following preferred embodiments of the invention in conjunction with the examples, but it is to be understood that the description is intended to further illustrate the features and advantages of the invention and is not intended to limit the scope of the claims which follow.
In order to prepare the high-performance neodymium iron boron magnetic powder with consistent orientation and higher coercivity, the powder structure is optimized in the powder preparation process, so that the anisotropic orientation of the neodymium iron boron magnetic powder is effectively optimized, and the coercivity of the neodymium iron boron magnetic powder is finally improved. Specifically, the embodiment of the invention discloses a preparation method of high-performance neodymium iron boron magnetic powder, which comprises the following steps:
a) Carrying out homogenization heat treatment on the neodymium iron boron rapid hardening alloy casting sheet shown as the formula (I);
b) Carrying out hydrogen crushing and air flow grinding on the neodymium iron boron quick-setting alloy cast sheet obtained in the step A) to obtain neodymium iron boron magnetic powder;
c) Carrying out HDDR treatment on the neodymium iron boron magnetic powder to obtain anisotropic HDDR magnetic powder;
d) Mixing the anisotropic HDDR magnetic powder with high-melting-point alloy powder to obtain mixed magnetic powder;
e) Carrying out heat treatment on the mixed magnetic powder at least once to obtain high-performance neodymium iron boron magnetic powder;
RE a T 100-a-b-c B b M c (Ⅰ)；
wherein RE is selected from one or more of Nd, pr, la, ce, dy and Tb;
t is selected from one or more of Fe, co and Ni;
m is selected from one or more of Ga, nb, zr, cu, al, V, ti, mo, si and Mn;
a. b and c respectively represent RE, B and M in percentage by weight of the whole, and the following conditions are met: a is more than or equal to 29.0wt% and less than or equal to 33.5wt%, b is more than or equal to 0.9wt% and less than or equal to 1.1wt%, and c is more than or equal to 0wt% and less than or equal to 3.5wt%.
The preparation flow of this application high performance neodymium iron boron magnetic powder is specifically as shown in figure 1, specifically is: the neodymium iron boron rapid hardening alloy sheet is subjected to homogenization heat treatment to obtain a coarsened columnar crystal alloy cast sheet, the alloy cast sheet is crushed through hydrogen breaking and airflow milling, then nanometer crystal grains are swallowed and grow through HDDR treatment, finally the refined crystal grains are mixed with high-melting-point alloy powder, heat treatment is carried out to prevent powder particles from adhering, inhibit the crystal grains from growing, and obtain high-performance neodymium iron boron magnetic powder with consistent orientation.
Specifically, the application firstly refers to the formula RE a T 100-a-b-c B b M c The cast sheet of the neodymium iron boron rapid hardening alloy is subjected to homogenization heat treatment. The original crystal grain size of the rapid hardening alloy casting sheet is smaller, and the crushed HDDR magnetic powder particles contain more original crystal grains with different orientations; the refined crystal grains after the HDDR treatment and the recombination stage are directly carried out inherit the texture orientation of the original crystal grains, so that the crystal grain texture orientation in the HDDR magnetic powder particles is disordered, the orientation consistency is low, and the final magnetic powder has poor anisotropy; on the basis, the application firstly homogenizes the rapid hardening alloyThe crystal grains of the original rapid-hardening alloy casting sheet grow up through heat treatment, the number of original crystal grains with different orientations contained in the crushed HDDR magnetic powder particles is reduced, and the orientation consistency of the crystal grains in the final HDDR magnetic powder particles is effectively improved; meanwhile, polycrystalline orientation disorder after heat treatment of the HDDR magnetic powder uniformly mixed in the subsequent preparation process can be effectively avoided, and the high-anisotropy magnetic powder with highly consistent grain orientation in particles can be prepared.
In the application, the chemical formula of the neodymium iron boron rapid hardening sheet alloy casting sheet is RE a T 100-a-b-c B b M c ；
Wherein RE is selected from one or more of Nd, pr, la, ce, dy and Tb;
t is selected from one or more of Fe, co and Ni;
m is selected from one or more of Ga, nb, zr, cu, al, V, ti, mo, si and Mn;
a. b and c respectively represent RE, B and M in percentage by weight of the whole, and the following conditions are met: a is more than or equal to 29.0wt% and less than or equal to 33.5wt%, b is more than or equal to 0.9wt% and less than or equal to 1.1wt%, and c is more than or equal to 0wt% and less than or equal to 3.5wt%.
More specifically, a is more than or equal to 30.0wt% and less than or equal to 32.0wt%, b is more than or equal to 0.9wt% and less than or equal to 1.1wt%, and c is more than or equal to 0.1wt% and less than or equal to 1.0wt%.
This application the neodymium iron boron rapid hardening piece alloy is cast the piece and is got rid of the piece through the rapid hardening stove, in this application, the thickness of the neodymium iron boron rapid hardening piece alloy is cast the piece is 200 ~ 300 mu m.
In the process of the homogenization heat treatment, the temperature of the homogenization heat treatment is 800-1500 ℃, the temperature rise rate is 5-15 ℃/min, the time is 1-10 h, and the vacuum degree is not less than 1 multiplied by 10 -2 Pa; more specifically, the temperature of the homogenization heat treatment is 900-1200 ℃, the heating rate is 5-10 ℃/min, and the time is 4-8 h.
This application carries out hydrogen breakage, jet mill with the neodymium iron boron rapid hardening alloy cast piece that above-mentioned obtained again to obtain the neodymium iron boron magnetic powder. Hydrogen crushing (HD) can ensure that the neodymium iron boron alloy absorbs hydrogen to form hydride to crush the alloy, and the rare earth-rich phase is firstly hydrogenated to cause crystal fracture, so most of HD powder is single crystal and the outer layer of powder particles is wrapped by the rare earth-rich phase; however, in the subsequent air flow milling process, the rare earth-rich phase on the outer layer of the main phase particles is easy to fall off; this is because the powder size after hydrogen crushing is larger than the target particle size (the target particle size is 2.5 μm), and finally, under the action of the continuous jet mill, although the powder size reaches the standard, the ideal particle component distribution after hydrogen crushing is also destroyed at the same time; therefore, if the directly pressed blank is sintered and densified, the distribution of non-ferromagnetic crystal boundaries is discontinuous, crystal grains are in direct contact, the magnetic isolation effect among the crystal grains is weakened, and the coercive force is low. The results of a large number of researches of the applicant show that the rare earth-rich phase can be extruded to the periphery of the particles only when the crystal swallows among the nanoscale crystal grains formed after the HDDR treatment are grown, so that the ideal component distribution of the main phase crystal grains uniformly coated by the rare earth-rich phase is formed. As the main phase crystal grains are well coated by the rare earth-rich phase, the demagnetization coupling effect between the sintered main phase crystal grains is effectively enhanced, and the coercive force of the magnet is greatly improved. The hydrogen fragmentation process of the present application specifically is: placing the neodymium iron boron rapid hardening alloy cast piece subjected to the homogenization heat treatment in hydrogen with the pressure of 100-300 kPa for absorbing hydrogen for 0.5-5 h, and after the hydrogen absorption is finished, dehydrogenating for 1-12 h at the temperature of 200-500 ℃; more specifically, the neodymium iron boron rapid hardening alloy cast sheet after the homogenization heat treatment is placed in hydrogen of 200 to 300kPa for hydrogen absorption for 1 to 5 hours, and after the hydrogen absorption is finished, the neodymium iron boron rapid hardening alloy cast sheet is dehydrogenated for 5 to 10 hours at the temperature of 300 to 500 ℃. The hydrogen-broken magnetic powder is then jet milled to a powder particle size of 1 to 10 μm, more specifically 1 to 5 μm.
According to the invention, the magnetic powder obtained above is then subjected to HDDR treatment to obtain an anisotropic HDDR magnetic powder. The magnetic powder is subjected to HDDR treatment, so that nano-scale grains in the grains are swallowed and grow, the rare earth-rich phase is extruded to the periphery of the grains, and ideal component distribution of the rare earth-rich phase uniformly coated with the main phase grains is formed. The HDDR treatment process specifically comprises the following steps:
a heating stage step: placing the neodymium iron boron magnetic powder in a hydrogen heat treatment furnace, and heating to 600-1000 ℃ in a vacuum environment;
step of hydrogenation disproportionation stage: introducing 10-80 kPa hydrogen into the hydrogen heat treatment furnace, and keeping the temperature and the pressure for 30-240 min;
slow dehydrogenation stage: adjusting the pressure of hydrogen in the furnace to be 1-10 kPa, and continuously keeping the temperature and the pressure for 30-100 min;
and a recombination stage: pumping the furnace to a vacuum degree of not less than 1 × 10 -2 Pa, and keeping the temperature for 20-60 min.
Mixing the magnetic powder subjected to the HDDR treatment with high-melting-point alloy powder to obtain mixed magnetic powder; the HDDR treatment can redistribute the rare earth-rich phase of the magnetic powder and easily cause direct contact between main phase grains, which is unfavorable for coercive force; meanwhile, when the heat treatment temperature reaches about 900 ℃, RE 2 Fe 14 B, the grain boundary is in a molten state, and the grains are easy to adhere during magnetic powder heat treatment; the invention prevents the rare earth-rich phase extruded around the particles from being melted to cause the particles to be adhered by adding the high-melting-point alloy and the HDDR magnetic powder to be uniformly mixed; the added high-melting-point alloy can simultaneously inhibit the growth of crystal grains in the subsequent magnetic powder sintering process, fully exert the advantage of fine grains and improve the coercive force. In the present application, the high melting point alloy powder is specifically selected from one or more of Ti, zr, V, nb, ta, hf, W, mo and Fe in an amount of 1 to 10wt% of the HDDR magnetic powder, more specifically, in an amount of 2 to 5wt% of the HDDR magnetic powder; excessive introduction of the high melting point alloy powder lowers the remanence.
The mixed magnetic powder is subjected to at least one heat treatment to obtain a high-performance neodymium iron boron magnet; so as to realize the inhibition effect of the high melting point alloy powder on the growth of magnetic powder grains and realize the fine grain effect. In the present application, the heat treatment is performed once, the temperature rise rate of the heat treatment is 5 to 15 ℃/min, the temperature is 500 to 1000 ℃, and the vacuum degree is not less than 1 × 10 - 2 Pa, the time is 1-10 h, and the cooling mode of the heat treatment is air quenching and air cooling; more specifically, the temperature rise speed of the heat treatment is 8-12 ℃/min, the temperature is 700-900 ℃, and the vacuum degree is not less than 1 multiplied by 10 -2 Pa, the time is 4-8 h.
The preparation method of the high-performance neodymium iron boron magnetic powder provided by the invention can be used for preparing the high-anisotropy HDDR magnetic powder with consistent orientation in batch, optimizing the component distribution of the magnetic powder and improving the coercive force of the magnetic powder, avoiding using heavy rare earth, and being simple and easy to operate and convenient to produce and apply.
For further understanding of the present invention, the following examples are given to illustrate the preparation method of the high performance neodymium iron boron magnetic powder provided by the present invention, and the scope of the present invention is not limited by the following examples.
Example 1
The chemical formula is prepared by a rapid hardening furnace and divided into (PrNd) according to the mass percentage 25.77 Ce 5.88 Al 0.15 Cu 0.2 Ga 0.1 Co 0.2 Zr 0.2 Fe bal. B 0.88 The rapid hardening alloy cast piece of (1); placing the prepared rapid hardening alloy cast piece in a vacuum heat treatment furnace, heating to 1080 ℃ at the heating rate of 10 ℃/min, preserving heat for 4 hours, then carrying out air quenching and air cooling, cooling to room temperature, taking out the rapid hardening alloy cast piece, placing the rapid hardening alloy cast piece in a hydrogen heat treatment furnace, introducing 200kPa hydrogen to absorb hydrogen for 4 hours, then dehydrogenating for 10 hours at 450 ℃, and then carrying out air flow grinding to obtain powder with the particle size of 1-3 microns;
putting the powder into a full-automatic hydrogen heat treatment furnace for HDDR treatment: firstly, the temperature is raised to 800 ℃, and 50kPa H is pumped in 2 Keeping the temperature and the pressure for 4h, pumping out hydrogen to 5kPa, keeping the temperature and the pressure for 90min, and then vacuumizing to 1 × 10 -2 Keeping the temperature and the pressure below Pa for 40min, and then carrying out air quenching and air cooling to room temperature to obtain HDDR powder; adding Hf accounting for 2% of the weight of the HDDR powder, uniformly mixing the powder, placing the powder in a vacuum heat treatment furnace, raising the temperature to 700 ℃ at a heating rate of 10 ℃/min, preserving the temperature for 3 hours, and then performing air quenching and air cooling to obtain the heat-treated HDDR magnetic powder.
The magnetic powder is mixed with epoxy resin and tested by PPMS, the magnetic powder Br =13.6kGs, hcj =12.6kOe, DOA =0.625 (DOA = (Br =) (∥) -Br (⊥) )/Br (∥) Wherein, the larger the DOA value is, the higher the anisotropy of the magnetic powder is, the better the orientation degree of the magnetic powder is and the higher the remanence is.
For comparison of the advantages of the present invention, a rapidly solidified alloy cast piece was subjected to hydrogen-blasting jet milling in a conventional manner, and the magnetic powder obtained after the HDDR treatment was used as comparative example 1. The magnetic powders prepared in example 1 and comparative example 1 were tested, and the performance data for example 1 and comparative example 1 are given in the following table:
table 1 table for data table of performance of neodymium iron boron magnetic powder prepared in different ways
| Magnetic powder type | Br(kGs) | Hcj(kOe) | DOA |
| Example 1 | 13.6 | 12.6 | 0.625 |
| Comparative example 1 | 12.6 | 10.1 | 0.401 |
By comparison, the following results are obtained: the magnetic performance and the orientation degree of the embodiment are obviously higher than those of a comparative example, the method has obvious advantages, and the ideal coating structure can be prepared to improve the performance of the magnetic powder and enhance the anisotropy.
Example 2
The chemical formula is prepared by a rapid hardening furnace according to the mass percentage of (NdPr) 31 Cu 0.2 Al 0.1 Zr 0.2 Co 0.5 Ga 0.1 Fe bal . B 0.9 The rapid hardening alloy cast piece of (1); placing the prepared rapid-hardening alloy cast piece in a vacuum heat treatment furnace, heating to 1100 ℃ at a heating rate of 10 ℃/min, preserving heat for 4h, then performing air quenching and air cooling, cooling to room temperature, taking out the rapid-hardening alloy cast piece, and placing the rapid-hardening alloy cast piece in a hydrogen heat treatment furnaceIntroducing 200kPa hydrogen for hydrogen absorption for 4h, dehydrogenating at 450 ℃ for 10h, and then carrying out jet milling to obtain powder of 1-3 mu m;
putting the powder into a full-automatic hydrogen heat treatment furnace for HDDR treatment: firstly heating to 840 ℃, introducing 50kPa hydrogen, keeping the temperature and the pressure for 4h, then pumping out the hydrogen to 3kPa, keeping the temperature and the pressure for 90min, and then pumping vacuum to 1 × 10 -2 Keeping the temperature and the pressure below Pa for 40min, and then carrying out air quenching and air cooling to room temperature to obtain HDDR powder; adding Nb according to 2 percent of the weight of the HDDR powder, uniformly mixing the powder, putting the powder in a vacuum heat treatment furnace, heating to 750 ℃ at a heating rate of 10 ℃/min, preserving the heat for 4 hours, and then performing gas quenching and air cooling to obtain the heat-treated HDDR magnetic powder.
The magnetic powder is mixed with epoxy resin and tested by PPMS, the magnetic powder Br =14.3kGs, hc =14.6kOe, DOA =0.723 (DOA = (Br =) (∥) -Br (⊥) )/Br (∥) The larger the DOA value is, the higher the anisotropy of the magnetic powder is, the better the orientation degree of the magnetic powder is, and the higher the remanence is.
In order to compare the advantages of the invention, the rapid-hardening alloy cast piece is subjected to hydrogen-breaking jet milling in a traditional mode, and the magnetic powder obtained after HDDR treatment is used as a comparative example 2; the magnetic powders prepared in example 2 and comparative example 2 were tested and the performance data for example 2 and comparative example 2 are given in the following table:
table 2 table of performance data of ndfeb magnetic powder prepared in different ways
| Magnetic powder type | Br(kGs) | Hcj(kOe) | DOA |
| Example 2 | 14.3 | 14.6 | 0.723 |
| In a conventional manner | 13.6 | 12.5 | 0.495 |
By comparison, it can be seen that: the magnetic performance and the orientation degree of the embodiment are obviously higher than those of a comparative example, the method has obvious advantages, and the ideal coating structure can be prepared to improve the performance of the magnetic powder and enhance the anisotropy.
Example 3
The chemical formula prepared by a rapid hardening furnace is Nd according to the mass percentage 26 Dy 4.1 B 1.1 Co 1.0 Fe bal. The rapid hardening alloy cast piece of (1); placing the prepared quick-setting alloy cast sheet in a vacuum heat treatment furnace, heating to 1080 ℃ at the heating rate of 10 ℃/min, carrying out air quenching and air cooling after 5 hours, taking out the quick-setting alloy cast sheet after cooling to room temperature, placing the quick-setting alloy cast sheet in a hydrogen heat treatment furnace, introducing 200kPa hydrogen to absorb hydrogen for 4 hours, dehydrogenating at 450 ℃ for 10 hours, and carrying out air flow milling to obtain powder with the particle size of 1-3 mu m;
putting the powder into a full-automatic hydrogen heat treatment furnace for HDDR treatment: firstly heating to 840 ℃, introducing 50kPa hydrogen, keeping the temperature and the pressure for 4h, then pumping out the hydrogen to 3kPa, continuing keeping the temperature and the pressure for 90min, and then pumping vacuum to 1X10 -2 Keeping the temperature and the pressure for 45min below Pa, and then carrying out air quenching and air cooling to room temperature to obtain HDDR powder; adding Zr according to 2% of the weight of the HDDR powder, uniformly mixing the powder, putting the powder in a vacuum heat treatment furnace, heating to 800 ℃ at a heating rate of 10 ℃/min, preserving the temperature for 4 hours, and then performing gas quenching and air cooling to obtain the heat-treated HDDR magnetic powder.
Mixing the magnetic powder with epoxy resin, and testing by PPMS, the magnetic powder has Br =13.2kGs, hcj =16.2kOe, DOA =0.654 (DOA = (Br =) (∥) -Br (⊥) )/Br (∥) Wherein, the larger the DOA value is, the higher the anisotropy of the magnetic powder is, the better the orientation degree of the magnetic powder is and the higher the remanence is.
In order to compare the advantages of the invention, the rapid-hardening alloy cast piece is subjected to hydrogen-breaking jet milling in a traditional mode, and the magnetic powder obtained after HDDR treatment is used as a comparative example 3; the magnetic powders prepared in example 3 and comparative example 3 were tested and the performance data for example 3 and comparative example 3 are given in the following table:
table 3 table for data of performance of ndfeb magnetic powder prepared in different ways
| Magnetic powder type | Br(kGs) | Hcj(kOe) | DOA |
| Example 3 | 13.2 | 16.2 | 0.654 |
| Comparative example 3 | 12.8 | 14.6 | 0.468 |
By comparison, it can be seen that: the magnetic performance and the orientation degree of the embodiment are obviously higher than those of a comparative example, the method has obvious advantages, and an ideal coating structure can be prepared to improve the performance of the magnetic powder and enhance the anisotropy.
The above description of the embodiments is only intended to facilitate the understanding of the method of the invention and its core idea. It should be noted that, for those skilled in the art, it is possible to make various improvements and modifications to the present invention without departing from the principle of the present invention, and those improvements and modifications also fall within the scope of the claims of the present invention.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (10)
1. A preparation method of high-performance neodymium iron boron magnetic powder comprises the following steps:
a) Carrying out homogenization heat treatment on the neodymium iron boron rapid hardening alloy casting sheet shown as the formula (I);
b) Carrying out hydrogen crushing and air flow grinding on the neodymium iron boron quick-setting alloy cast sheet obtained in the step A) to obtain neodymium iron boron magnetic powder;
c) Carrying out HDDR treatment on the neodymium iron boron magnetic powder to obtain HDDR magnetic powder;
d) Mixing the HDDR magnetic powder with high-melting-point alloy powder to obtain mixed magnetic powder;
e) Carrying out at least one heat treatment on the mixed magnetic powder to obtain high-performance neodymium iron boron magnetic powder;
RE a T 100-a-b-c B b M c (Ⅰ)；
wherein RE is selected from one or more of Nd, pr, la, ce, dy and Tb;
t is selected from one or more of Fe, co and Ni;
m is selected from one or more of Ga, nb, zr, cu, al, V, ti, mo, si and Mn;
a. b and c respectively represent RE, B and M in percentage by weight of the whole, and the following conditions are met: a is more than or equal to 29.0wt% and less than or equal to 33.5wt%, b is more than or equal to 0.9wt% and less than or equal to 1.1wt%, and c is more than or equal to 0wt% and less than or equal to 3.5wt%.
2. The method according to claim 1, wherein the refractory alloy powder is one or more selected from the group consisting of Ti, zr, V, nb, ta, hf, W, mo, and Fe.
3. The process according to claim 1 or 2, wherein the temperature of the homogenization heat treatment is 800 to 1500 ℃, the temperature rise rate is 5 to 15 ℃/min, the time is 1 to 10 hours, and the degree of vacuum is not less than 1x10 -2 Pa。
4. The method according to claim 1 or 2, wherein the hydrogen fragmentation is carried out in particular by:
placing the neodymium iron boron rapid hardening alloy casting sheet obtained in the step A) in hydrogen of 100-300 kPa for hydrogen absorption for 0.5-5 h, and after the hydrogen absorption is finished, dehydrogenating for 1-12 h at 200-500 ℃.
5. The method according to claim 1 or 2, wherein the particle size of the neodymium iron boron magnetic powder is 1-10 μm.
6. The method according to claim 1 or 2, wherein the HDDR treatment process is specifically:
a heating stage: placing the neodymium iron boron magnetic powder in a hydrogen heat treatment furnace, and heating to 600-1000 ℃ in a vacuum environment;
a hydrogenation disproportionation stage: introducing 10-80 kPa hydrogen into the hydrogen heat treatment furnace, and keeping the temperature and the pressure for 30-240 min;
and (3) a slow dehydrogenation stage: adjusting the pressure of hydrogen in the furnace to be 1-10 kPa, and continuously keeping the temperature and the pressure for 30-100 min;
and a recombination stage: pumping the furnace to a vacuum degree of not less than 1 × 10 -2 Pa, and keeping the temperature for 20-60 min.
7. The method according to claim 1 or 2, wherein the high melting point alloy powder is 1 to 10wt% of the HDDR magnetic powder.
8. The production method according to claim 1 or 2, wherein the number of the heat treatments is one, the temperature rise rate of the heat treatment is 5 to 15 ℃/min, the temperature is 500 to 1000 ℃, and the degree of vacuum is not less than 1x10 -2 Pa, the time is 1-10 h.
9. The method according to claim 1 or 2, wherein the heat treatment is cooled by air quenching and air cooling.
10. The production method according to claim 1 or 2, wherein a is 30.0% by weight or more and 32.0% by weight or less, b is 0.9% by weight or more and 1.1% by weight or less, and c is 0.1% by weight or more and 1.0% by weight or less.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211354286.4A CN115763030A (en) | 2022-11-01 | 2022-11-01 | Preparation method of high-performance neodymium iron boron magnetic powder |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211354286.4A CN115763030A (en) | 2022-11-01 | 2022-11-01 | Preparation method of high-performance neodymium iron boron magnetic powder |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN115763030A true CN115763030A (en) | 2023-03-07 |
Family
ID=85354867
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202211354286.4A Pending CN115763030A (en) | 2022-11-01 | 2022-11-01 | Preparation method of high-performance neodymium iron boron magnetic powder |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115763030A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117275864A (en) * | 2023-10-08 | 2023-12-22 | 江苏普隆磁电有限公司 | Preparation method and application of high-performance neodymium-iron-boron magnet |
-
2022
- 2022-11-01 CN CN202211354286.4A patent/CN115763030A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117275864A (en) * | 2023-10-08 | 2023-12-22 | 江苏普隆磁电有限公司 | Preparation method and application of high-performance neodymium-iron-boron magnet |
| CN117275864B (en) * | 2023-10-08 | 2024-05-03 | 江苏普隆磁电有限公司 | Preparation method and application of high-performance neodymium-iron-boron magnet |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN110931197B (en) | Diffusion source for high-abundance rare earth permanent magnet | |
| CN103985533B (en) | Eutectic alloy Hydride Doped improves the coercitive method of Sintered NdFeB magnet | |
| CN104505206A (en) | Preparation method of high-coercivity sintered Nd-Fe-B and product | |
| CN102368439B (en) | Optimization process method for preparing high-coercivity permanent magnet by adding heavy rare earth hydroxide into neodymium iron boron | |
| CN102610347A (en) | Rare earth permanent magnet alloy material and preparation process thereof | |
| JP5640946B2 (en) | Method for producing sintered body as rare earth magnet precursor | |
| CN104851545B (en) | A kind of permanent-magnet material preparation method with grain boundary decision layer | |
| JPH01704A (en) | Rare earth-iron permanent magnet | |
| KR102215818B1 (en) | Hot-deformed magnet comprising nonmagnetic alloys and fabricating method thereof | |
| WO2014190558A1 (en) | Rare-earth permanent magnetic powders, bonded magnet comprising same, and device using bonded magnet | |
| WO2023124688A1 (en) | Neodymium-iron-boron magnet as well as preparation method therefor and use thereof | |
| CN104575920A (en) | Rare-earth permanent magnet and production method thereof | |
| JP2018534762A (en) | PERMANENT MAGNETIC MATERIAL AND METHOD FOR PREPARING THE SAME | |
| CN113223807B (en) | Neodymium-iron-boron permanent magnet and preparation method and application thereof | |
| CN109859922A (en) | A kind of preparation method of the R-Fe-B magnet of low heavy rare earth content | |
| CN115763030A (en) | Preparation method of high-performance neodymium iron boron magnetic powder | |
| EP4439595A1 (en) | Preparation method for flaky anisotropic nanocrystalline rare earth permanent magnet material, and rare earth permanent magnet material | |
| CN109754970B (en) | Rare earth magnet and preparation method thereof | |
| WO2024114167A1 (en) | Sintered neodymium-ferrum-boron magnet and preparation method therefor | |
| CN110473684B (en) | Preparation method of high-coercivity sintered neodymium-iron-boron magnet | |
| JP5742733B2 (en) | Rare earth magnet manufacturing method | |
| CN111161949A (en) | YCe co-doped nanocrystalline rare earth permanent magnet and preparation method thereof | |
| JP6179709B2 (en) | R-T-B rare earth magnet powder, method for producing R-T-B rare earth magnet powder, and bonded magnet | |
| CN113205939B (en) | Zirconium-containing sintered neodymium-iron-boron magnet and preparation method thereof | |
| JP2002075715A (en) | Anisotropic bulk exchange spring magnet and manufacturing method thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |