CN114300210B - Rare earth hydrogenated metal powder, neodymium iron boron magnet and preparation method thereof - Google Patents
Rare earth hydrogenated metal powder, neodymium iron boron magnet and preparation method thereof Download PDFInfo
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Abstract
The invention relates to rare earth hydrogenated metal powder, a neodymium iron boron magnet and a preparation method thereof. The preparation method of the rare earth hydrogenated metal powder comprises the steps of mixing and smelting doped metal and heavy rare earth metal to obtain heavy rare earth alloy with a specific composition, crushing the heavy rare earth alloy, performing activation treatment to obtain heavy rare earth alloy particles, performing first hydrogen absorption treatment, dehydrogenation treatment and second hydrogen absorption treatment on the heavy rare earth alloy particles in sequence, and cooling to obtain the rare earth hydrogenated metal powder. The rare earth hydrogenation metal powder prepared by the method can improve the consistency of the diffusion of the magnet grain boundary, thereby improving the coercive force and the anti-thermal demagnetization characteristic of the neodymium iron boron magnet on the basis of basically not influencing the remanence.
Description
Technical Field
The invention relates to the technical field of rare earth material preparation, in particular to rare earth hydrogenated metal powder, a neodymium iron boron magnet and a preparation method thereof.
Background
Neodymium-iron-boron magnet, namely sintered neodymium-iron-boron, is an important rare earth functional material, mainly is a tetragonal crystal formed by neodymium (praseodymium-neodymium), iron and boron, and the magnetic energy product (BH) max of the neodymium-iron-boron magnet is larger than that of a samarium-cobalt magnet, and is the most commonly used rare earth magnet. Since its discovery in 1983, ndfeb magnets have rapidly gained widespread use in modern industry and electronics, such as computer hard drives, cell phones, headsets, variable frequency air conditioners, energy efficient elevators, industrial motors, and the like.
With the development of new energy and new infrastructure, to realize miniaturization and high-temperature service of devices, the neodymium-iron-boron magnet with high comprehensive magnetic performance, high remanence and high coercivity, is required. The remanence and the coercive force have a 'carrying pole' relationship, if the coercive force is improved by adding heavy rare earth terbium or dysprosium in the traditional direct smelting stage, the remanence is inevitably reduced, and therefore, a grain boundary diffusion method is provided, namely Dy/Tb is utilized 2 Fe 14 The magnetocrystalline anisotropy field of the B phase is far larger than that of Nd 2 Fe 14 B, through a special process, Dy/Tb diffuses along the grain boundary and does not enter the main phase crystal, so that the coercive force is increased and the remanence is maintained.
At present, the grain boundary diffusion technology has attracted extensive attention and is becoming mature, and the preparation methods mainly include evaporation, coating, magnetron sputtering, electrophoretic deposition and the like. The coating method is better applied due to less investment and low cost, Dy/Tb metal powder or Dy/Tb compound powder is attached to the surface of the neodymium-iron-boron magnetic sheet to form a coating by the processes of dipping, smearing, spraying and the like, the grain boundary composition and the organizational structure of the material are improved by heat treatment to improve the coercive force of the sintered neodymium-iron-boron magnetic sheet so as to realize double-high comprehensive magnetic performance, and experimental research shows that: the Dy/Tb hydrogenated powder has better effect than Dy/Tb metal, oxide, fluoride and the like. However, Dy/Tb hydrogenated powder produced by the conventional technology increases the cost of metal for pursuing high purity, and it is still difficult to satisfy the heat resistance of sintered nd-fe-b magnet after application.
Thus, the prior art remains to be improved.
Disclosure of Invention
Based on the rare earth hydrogenated metal powder, the neodymium iron boron magnet and the preparation method thereof, the rare earth hydrogenated metal powder prepared by the preparation method of the rare earth hydrogenated metal powder can improve the coercive force and the anti-thermal demagnetization characteristic of the neodymium iron boron magnet on the basis of basically not influencing the residual magnetism.
In one aspect of the present invention, there is provided a method for preparing a rare earth metal hydride powder, comprising the steps of;
(1) mixing and smelting the doped metal and the heavy rare earth metal to obtain a heavy rare earth alloy;
(2) crushing the heavy rare earth alloy, activating to obtain heavy rare earth alloy particles, sequentially carrying out first hydrogen absorption treatment, dehydrogenation treatment and second hydrogen absorption treatment on the heavy rare earth alloy particles, and cooling to obtain rare earth hydrogenated metal powder;
the heavy rare earth alloy comprises the following components in percentage by mass: 0.5% -1% of the doped metal, 97.5% -99.3% of the heavy rare earth metal and the balance of other impurities; the doped metal is selected from at least one of tungsten and molybdenum;
the pressure of the hydrogen in the first hydrogen absorption treatment and/or the second hydrogen absorption treatment is 150 KPa.G-200 KPa.G, and the temperature is not more than 400 ℃; the pressure of the dehydrogenation treatment is less than 20Pa, and the temperature is 600-750 ℃.
In some of these embodiments, the rare earth hydride metal powder is substituted for the heavy rare earth alloy particles, and the first hydrogen absorption treatment, the dehydrogenation treatment, and the second hydrogen absorption treatment in step (2) are sequentially repeated N times, where N is an integer greater than or equal to 1.
In some embodiments, the vacuum degree of the activation treatment is less than 5Pa, the temperature is 650-850 ℃, and the time is 5-30 min.
In some embodiments, the step of mixing smelting specifically comprises the steps of:
placing the heavy rare earth metal and the doped metal in a crucible for melting refining, and cooling to obtain the heavy rare earth alloy; the heavy rare earth alloy comprises the following components in percentage by mass: 0.5% -1% of the doped metal, 97.5% -99.3% of the heavy rare earth metal and the balance of other impurities;
the crucible is made of at least one of tungsten and molybdenum.
In some of these embodiments, the steps of the activation treatment, the first hydrogen absorption treatment, the dehydrogenation treatment, the second hydrogen absorption treatment, and the cooling in step (2) are performed in a stationary hydrogen-breaking furnace; and/or
The heavy rare earth metal is at least one of terbium and dysprosium.
In some of these embodiments, the cooling step is performed in an inert atmosphere at a pressure of 390KPa.G to 410 KPa.G.
In another aspect of the present invention, there is provided a rare earth hydride metal powder produced by the method for producing a rare earth hydride metal powder as described above.
In another aspect of the present invention, there is provided a neodymium iron boron magnet, which is prepared from raw materials including a neodymium iron boron base body and the rare earth metal hydride powder as claimed in the claims.
In another aspect of the present invention, a method for preparing a neodymium iron boron magnet is provided, which includes the following steps:
mixing the rare earth metal hydride powder with a solvent to obtain a suspension;
and coating the suspension on the surface of a neodymium iron boron substrate to form a coating, and then carrying out heat treatment to obtain the neodymium iron boron magnet.
In some of these embodiments, the coating has a thickness of 0.5mm to 3.0 mm.
The preparation method of the rare earth hydrogenated metal powder comprises the steps of mixing and smelting the doped metal and the heavy rare earth metal, infiltrating the doped metal with specific types and proportion into the heavy rare earth metal to obtain the heavy rare earth alloy, crushing and activating the heavy rare earth alloy, then carrying out hydrogen absorption-dehydrogenation treatment under specific conditions, introducing the doped metal with high melting point and strong hydrogen absorption capacity by controlling the types and specific contents of the doped metal, having strong permeability, facilitating the diffusion of the heavy rare earth metal in the rare earth hydrogenated metal powder along the grain boundary phase of the neodymium iron boron matrix, improving the hydrogen saturation of the rare earth hydrogenated metal, reducing the oxygen content, further improving the hydrogen saturation of the rare earth hydrogenated metal, controlling the oxygen content, obtaining hydrogenated metal powder with uniform particle size distribution and improving the particle size uniformity of the obtained rare earth hydrogenated metal powder by controlling the pressure and the temperature of hydrogen absorption-dehydrogenation, and the consistency of the diffusion of the magnet grain boundary is improved, so that the coercive force and the anti-thermal demagnetization characteristic of the neodymium iron boron magnet can be improved on the basis of basically not influencing the remanence.
Further, replacing the heavy rare earth alloy particles with the rare earth hydrogenation metal powder obtained in the step (2), and repeating the first hydrogen absorption treatment, the dehydrogenation treatment and the second hydrogen absorption treatment for N times, wherein N is an integer greater than or equal to 1. Thus, the particle size uniformity of the rare earth metal hydride powder can be further improved; further, the step (2) is carried out in a static hydrogen crushing furnace, and compared with the traditional process for preparing hydride by adopting a rotary hydrogen crushing furnace, the static hydrogen crushing furnace is adopted, so that the generation of fine powder with the particle size of less than 1 mu m is favorably reduced.
The rare earth hydrogenated metal powder is prepared by the preparation method of the rare earth hydrogenated metal powder, has high hydrogenation degree, low oxygen content, uniform particle size distribution, specific content of doped metal and strong permeability, is favorable for the diffusion of heavy rare earth metal along the grain boundary phase of the neodymium iron boron matrix, and improves the consistency of the diffusion of the grain boundary of the magnet, thereby improving the coercivity, ensuring the remanence and improving the anti-thermal demagnetization property.
The raw materials for preparing the neodymium iron boron magnet comprise a neodymium iron boron base body and the rare earth hydrogenated metal powder, so that the high coercive force is achieved, the remanence is guaranteed, the thermal demagnetization resistance is excellent, and the comprehensive performance is excellent.
In the preparation method of the neodymium iron boron magnet, the rare earth hydrogenated metal powder and the solvent are mixed to obtain suspension; and coating the suspension on the surface of the neodymium iron boron matrix to form a coating, and then carrying out heat treatment, wherein the particle size of the rare earth hydrogenated metal powder is moderate and the powder is uniformly distributed, so that the powder in the prepared suspension is uniformly distributed, the uniformity and consistency of the coating are improved, the heavy rare earth metal is favorably diffused along the grain boundary of the neodymium iron boron matrix, and the consistency of the diffusion of the grain boundary of the magnet is improved, thereby improving the coercive force and the anti-thermal demagnetization characteristic of the neodymium iron boron magnet on the basis of basically not influencing residual magnetism.
Detailed Description
In order that the invention may be more fully understood, reference will now be made to the following more detailed description. The preferred embodiments of the present invention are given in the detailed description. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.
When the coating method is adopted to carry out grain boundary diffusion treatment on the magnet, the distribution uniformity and the thickness consistency of the coating are one of key technologies for improving the magnetic performance of the neodymium iron boron magnet by using the grain boundary diffusion technology and realizing industrialization. In the dipping, smearing and spraying methods, the agglomeration of powder in suspension and the size matching degree of powder particles influence the uniformity and consistency of a coating, and the hydrogenation degree and the component content of the hydrogenated metal also influence the permeability of the hydrogenated metal, thereby influencing the effect of grain boundary diffusion.
The traditional coating method has certain requirements on the neodymium iron boron magnet matrix, the lower the heavy rare earth content of the neodymium iron boron magnet matrix is, the higher the content of the heavy rare earth which can permeate into the neodymium iron boron magnet matrix is, and the better the effect of improving the coercive force is.
Based on this, the technical personnel of the invention creatively propose to further the comprehensive performance of the neodymium iron boron magnet by improving the composition of the rare earth hydrogenated metal powder containing heavy rare earth metals. After a large number of creative experiments, the rare earth hydrogenated metal powder, the neodymium iron boron magnet and the preparation method thereof are obtained. The specific technical scheme is as follows.
An embodiment of the present invention provides a method for preparing a rare earth metal hydride powder, including the following steps.
Step (1), mixing and smelting doped metal and heavy rare earth metal to obtain heavy rare earth alloy;
the heavy rare earth alloy comprises the following components in percentage by mass: 0.5-1% of doped metal, 97.5-99.3% of heavy rare earth metal and the balance of other impurities.
Crushing the heavy rare earth alloy, activating to obtain heavy rare earth alloy particles, sequentially performing first hydrogen absorption treatment, dehydrogenation treatment and second hydrogen absorption treatment on the heavy rare earth alloy particles, and cooling to obtain rare earth hydrogenated metal powder; the pressure of hydrogen in the first hydrogen absorption treatment and/or the second hydrogen absorption treatment is 150 KPa.G-200 KPa.G, and the temperature is not more than 400 ℃; the pressure of dehydrogenation treatment is less than 20Pa, and the temperature is 600-750 ℃.
The preparation method of the rare earth hydrogenated metal powder comprises the steps of mixing and smelting the doped metal and the heavy rare earth metal, infiltrating the specific doped metal into the heavy rare earth metal to obtain the heavy rare earth alloy, crushing and activating the heavy rare earth alloy, then carrying out hydrogen absorption-dehydrogenation treatment under specific conditions, introducing the doped metal with high melting point and strong hydrogen absorption capacity by controlling the type and specific content of the doped metal, having strong permeability, being beneficial to the diffusion of the heavy rare earth metal in the rare earth hydrogenated metal powder along the crystal boundary of a neodymium iron boron matrix, improving the hydrogen saturation of the rare earth hydrogenated metal, controlling the oxygen content, further improving the hydrogen saturation of the rare earth hydrogenated metal and controlling the oxygen content by controlling the pressure and temperature of the hydrogen absorption-dehydrogenation, simultaneously obtaining the rare earth hydrogenated metal powder with uniform particle size distribution, and improving the particle size uniformity of the obtained rare earth hydrogenated metal powder, and the consistency of the diffusion of the magnet grain boundary is improved, so that the coercive force and the anti-thermal demagnetization characteristic of the neodymium iron boron magnet can be improved on the basis of basically not influencing the remanence.
It is understood that the other impurities mentioned above refer to inevitable impurities brought by the metal raw materials, including but not limited to: oxygen, carbon, calcium, iron, and the like.
Further, the heavy rare earth alloy comprises, by mass, 0.5% -1% of doped metal, 0.05% -0.1% of oxygen, 0.01% -0.03% of carbon, 0.1% -0.2% of calcium, 0.01% -0.03% of iron and 97.5% -99.3% of heavy rare earth metal.
It should be noted that, in the hydrogen absorption process, as the metal continuously absorbs hydrogen, the hydrogen pressure will float, so the hydrogen pressure range needs to be controlled, the hydrogen pressure will decrease with the consumption of hydrogen, and decrease to 150kpa.g, and the hydrogen will be supplemented, and the pressure will be refilled to 200kpa.g, so the hydrogenation saturation of the metal is ensured. The time of hydrogen absorption treatment can be adjusted according to the amount of the materials, and when the hydrogen pressure does not decrease within 20 minutes, the hydrogenation of the metal is saturated, and the hydrogen absorption is stopped.
Further, since the hydrogen absorption process is an exothermic reaction, the temperature in the furnace rises, so that it is necessary to control the temperature to not more than 400 ℃.
Such heavy rare earth metals include, but are not limited to: at least one of gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), and yttrium (Y).
In some of these embodiments, the heavy rare earth metal is selected from at least one of terbium and dysprosium.
In some of the embodiments, in the step (2), the rare earth hydrogenation metal powder is substituted for the heavy rare earth alloy particles, and the first hydrogen absorption treatment, the dehydrogenation treatment and the second hydrogen absorption treatment are sequentially repeated for N times, where N is an integer greater than or equal to 1.
Thus, the uniformity of the particle diameter of the rare earth metal hydride powder can be further improved.
In some embodiments, when the first hydrogen absorption treatment, the dehydrogenation treatment and the second hydrogen absorption treatment are repeated in sequence for N times, the cooling treatment is performed after each repetition is completed; in other words, the cooling process is performed after each second hydrogen absorption process.
In some of the embodiments, when the first hydrogen absorption treatment, the dehydrogenation treatment, and the second hydrogen absorption treatment are repeated N times, the activation treatment is performed before each of the first hydrogen absorption treatments.
In some of the embodiments, the temperature of the first hydrogen absorption treatment and/or the second hydrogen absorption treatment is 25 ℃ to 400 ℃.
In some of the embodiments, the pressure of the dehydrogenation treatment is 0Pa to 20 Pa. Further, the time of dehydrogenation reaction is 1-3 h.
In some embodiments, the vacuum degree of the activation treatment is less than 5Pa, the temperature is 650-850 ℃, and the time is 5-30 min.
The activation treatment can activate the metal surface, reduce the free energy of the system, further control the specific conditions of the activation treatment, be beneficial to activating the metal and be beneficial to absorbing hydrogen subsequently.
In some of the embodiments, before the hydrogen crushing step, the step of crushing the heavy rare earth alloy is further included.
The prepared heavy rare earth alloy is generally in a block shape or a spindle, and in order to increase the reaction speed, the heavy rare earth alloy needs to be crushed to obtain a larger specific surface area, and the crushing mode is not limited to shearing, oil press crushing and the like.
In some of the embodiments, the steps of the activation treatment, the first hydrogen absorption treatment, the dehydrogenation treatment, the second hydrogen absorption treatment and the cooling in the step (2) are performed in a static hydrogen crushing furnace.
And (3) the step (2) is carried out in a standing hydrogen crushing furnace, and compared with the traditional process for preparing hydride by adopting a rotary hydrogen crushing furnace, the standing hydrogen crushing furnace is favorable for reducing the generation of fine powder with the particle size of less than 1 mu m.
In some of these embodiments, the step of cooling is performed in an inert atmosphere at a pressure of 390KPa.G to 410 KPa.G.
Inert gases include, but are not limited to: at least one of helium (He), neon (Ne), argon (Ar) and krypton (Kr).
In some embodiments, the step of mixing smelting specifically includes the following step S11.
S11, placing the heavy rare earth metal and the doped metal in a crucible for melting refining, and cooling to obtain a heavy rare earth alloy; the crucible is made of at least one of tungsten and molybdenum.
During the melt refining, there is a dopant metal incorporated into the molten heavy rare earth metal. The heavy rare earth alloy comprises the following components in percentage by mass: 0.5-1% of doped metal, 97.5-99.3% of heavy rare earth metal and the balance of other impurities.
In some of these embodiments, the melt refining temperature is from 1410 ℃ to 1600 ℃; the mass ratio of the added doped metal to the heavy rare earth metal is (1-3) to (1-5).
Further, the heavy rare earth metal is prepared by reducing fluoride containing the heavy rare earth metal, and the reducing agent adopted in the reduction reaction is calcium.
In one embodiment of the present invention, there is provided a rare earth hydride metal powder prepared by the method for preparing a rare earth hydride metal powder as described above.
The rare earth hydrogenated metal powder is prepared by the preparation method of the rare earth hydrogenated metal powder, has high hydrogenation degree, low oxygen content, uniform particle size distribution, specific content of doped metal and strong permeability, is beneficial to the diffusion of heavy rare earth metal along the grain boundary of the neodymium iron boron matrix, and improves the consistency of the diffusion of the grain boundary of the magnet, thereby improving the coercive force and the anti-thermal demagnetization characteristic of the neodymium iron boron magnet on the basis of basically not influencing the residual magnetism.
The invention further provides a neodymium iron boron magnet, and the raw materials for preparing the neodymium iron boron magnet comprise a neodymium iron boron base body and the rare earth hydrogenated metal powder.
The raw materials for preparing the neodymium iron boron magnet comprise a neodymium iron boron base body and the rare earth hydrogenated metal powder, so that the neodymium iron boron magnet has high coercivity, ensures remanence, has excellent anti-thermal demagnetization characteristics and has excellent comprehensive performance.
The invention further provides a preparation method of the neodymium iron boron magnet, which comprises the following steps of S20-S30.
Step S20, mixing the rare earth metal hydride powder with a solvent to obtain a suspension.
And step S30, coating the suspension on the surface of the neodymium iron boron substrate to form a coating, and then carrying out heat treatment to obtain the neodymium iron boron magnet.
In the preparation method of the neodymium iron boron magnet, the rare earth hydrogenated metal powder and the solvent are mixed to obtain suspension; and then coating the suspension on the surface of the neodymium iron boron matrix to form a coating, and then carrying out heat treatment, wherein the particle size of the hydrogenated metal powder is moderate and the powder is uniformly distributed, the powder distribution in the prepared suspension is uniform, the uniformity and consistency of the coating are improved, the heavy rare earth metal is favorably diffused along the grain boundary of the neodymium iron boron matrix, and the consistency of the diffusion of the grain boundary of the magnet is improved, so that the coercive force and the anti-thermal demagnetization characteristic of the neodymium iron boron magnet can be improved on the basis of basically not influencing the remanence, and the operation is simple.
It is understood that the above coating steps may employ coating processes commonly used in the art, including but not limited to: dipping, painting, spraying, etc.
In some embodiments, the rare earth metal hydride powder has a particle size of 5 μm to 50 μm, preferably 15 μm to 35 μm.
In some embodiments, the method further comprises the step of sieving the rare earth metal hydride powder before the step of mixing the rare earth metal hydride powder with the solvent.
Specifically, wet sieving is carried out on hydrogen crushed aggregates in a nitrogen-protected glove box, namely, inert and anti-oxidation solvent is adopted to soak the powders, a certain number of stainless steel sieves are used for sieving, a small amount of oversize products are obtained after sieving, vacuum drying is carried out, then hydrogenation treatment is carried out again, the undersize products are subjected to vacuum heating drying, and after drying and cooling, vacuumizing packaging is carried out in an argon-protected glove box. The inert solvent adopts a non-hygroscopic and volatile ketone organic solvent, and acetone is preferred.
Furthermore, the mass volume ratio of the rare earth hydrogenation metal powder to the solvent is (15-30) g:1 mL.
In some of these embodiments, the solvent in step S20 is selected from small molecule alcohols, including but not limited to ethanol, propanol, and the like.
In some embodiments, the thickness of the coating is 0.5mm to 3.0 mm.
In some embodiments, the neodymium iron boron matrix comprises, by mass, 27.5% -33.5% of praseodymium and/or neodymium, 60% -65.5% of iron, 0.83% -1.0% of boron, 0% -2.0% of heavy rare earth metal, and the balance impurities.
While the present invention will be described with respect to particular embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but is intended to cover by the appended claims the scope of the invention, and that certain changes in the embodiments of the invention will be suggested to those skilled in the art and are intended to be covered by the appended claims.
DETAILED DESCRIPTION OF EMBODIMENT (S) OF INVENTION
The following are specific examples.
Example 1
(1) Carrying out fluorination reaction on 10Kg of terbium oxide with the relative purity of more than or equal to 99.5% by HF gas to convert the terbium fluoride, mixing the terbium fluoride and 99% of calcium metal according to the proportion of excessive calcium of 25wt%, then adding the mixed material into a tungsten crucible, placing the tungsten crucible in a medium-frequency vacuum casting furnace, reducing under the protection of argon, pouring, cooling by a water-cooled copper mold, stripping metal slag, cleaning calcium doped with metal to obtain a metal terbium block, cutting the metal terbium block into small blocks, placing the small blocks into the tungsten crucible, placing a tungsten bar which is 10mm thick and has the height of 3 two thirds of the crucible and the inner diameter of one fifth of the crucible on the inner wall lining of the tungsten crucible, wherein the mass ratio of the metal terbium block to the tungsten bar is 100: and 20, placing the alloy in a vacuum tantalum sheet furnace, refining for 1h at 1600 ℃ and argon pressure, pouring the refined alloy into a water-cooled copper mold, and cooling to obtain the heavy rare earth alloy.
The prepared heavy rare earth alloy is sampled and subjected to component analysis, and the result shows that: the heavy rare earth alloy comprises, by mass, 0.95% of tungsten, 0.14% of oxygen, 0.018% of carbon, 0.018% of calcium, 0.065% of iron, 98.5% of terbium and the balance impurities.
(2) Crushing the prepared heavy rare earth alloy into particles with the size of 1.5cm by using an oil press, filling the particles into a clean and dry graphite box, and conveying the graphite box into a vacuum chamber with the ultimate vacuum of less than 8 multiplied by 10 -2 Pa and the pressure rise rate is less than 1 Pa/h. And (3) carrying out conventional positive and negative leakage detection on the hydrogen crushing furnace, vacuumizing to below 5Pa, starting heating to 850 ℃, and keeping the temperature for 30min for activation treatment. Stopping heating after heat preservation, closing a vacuum system, cooling to 400 ℃, filling hydrogen with the purity of 99.99%, filling the pressure in the furnace to 200KPa.G, setting the variation range of the hydrogen pressure to be 150 KPa.G-200 KPa.G, and setting the hydrogen absorption positionThe hydrogen pressure was allowed to stand for 2 hours until no further change in hydrogen pressure was observed within 20 minutes.
Then argon is introduced for dilution, and hydrogen in the furnace is gradually discharged. And (3) exhausting after argon replacement, vacuumizing to below 5Pa, heating to 600 ℃, and preserving heat for dehydrogenation treatment for 3 hours. After the hydrogen is removed, the pressure is within 20Pa, argon is filled to 400KPa.G, then a fan is started to cool, and the temperature in the furnace is reduced to about 100 ℃.
After repeating the above hydrogen absorption-dehydrogenation 1 time, the temperature in the furnace was again raised to 250 ℃ to stop heating, and hydrogen absorption treatment was further performed for 2 hours according to the above-mentioned dehydrogenation treatment operation. And (3) performing argon replacement and argon protection, performing self-cooling to 150 ℃, starting air cooling for forced cooling, and pouring the materials into a charging bucket under the protection of inert gases such as argon and the like when the temperature in the furnace is kept for 1h and is stabilized below 30 ℃ to obtain the rare earth hydrogenated metal powder.
Through detection: the rare earth metal hydride powder has an oxygen content of 0.16% and a carbon content of 0.018%, and the particle sizes are measured by a wet particle size analyzer, and the results show that D (97) is 35.6 μm and D (10) is 7.25 μm
(3) In a glove box protected by nitrogen, a protective solvent of acetone is adopted, a 100-mesh stainless steel sieve is used for wet sieving, and then vacuum drying is carried out. Mixing the sieved hydrogenated metal powder and absolute ethyl alcohol into suspension according to the proportion of 30g to 1mL, spraying the powder on a cleaned neodymium iron boron substrate sheet by using spraying equipment, wherein the neodymium iron boron substrate sheet is a sintered neodymium iron boron 48SH square product containing dysprosium and holmium by more than 3.5wt%, the thickness of the coating is 1mm, and the sprayed product is subjected to heat treatment by using a vacuum annealing furnace, and the heat treatment procedure is as follows: and (3) cooling the magnet at 900 ℃ for 8h +510 ℃ for 6h, and taking out the magnet from the furnace to obtain the neodymium-iron-boron magnet.
(4) And (3) testing performance: and testing the remanence, intrinsic coercivity, maximum energy product, squareness and thermal demagnetization of the prepared neodymium iron boron magnet, wherein the testing process is in reference to the standard GB/T3217. See table 1 for specific results.
Example 2
Example 2 is substantially the same as example 1 except that: example 2 in step (1), a molybdenum crucible was used instead of the tungsten crucible in step (1) of example 1, and a molybdenum plate was used instead of the tungsten bar. The components of the prepared heavy rare earth alloy comprise 0.93 percent of molybdenum, 0.15 percent of oxygen, 0.02 percent of carbon, 0.018 percent of calcium, 0.071 percent of iron, 98.3 percent of terbium and the balance of impurities.
The other steps and process parameters were the same as in example 1.
Example 3
Example 3 is essentially the same as example 1, except that: example 3 step (1) is as follows: 10Kg of dysprosium oxide with the relative purity of more than or equal to 99.5 percent is subjected to fluorination reaction by an ammonium bifluoride dry method to be converted into dysprosium fluoride, 99 percent of metallic calcium is added according to the excessive proportion of 22 weight percent, then the mixed material is added into a tungsten crucible and placed in a medium-frequency vacuum casting furnace, reduction and casting are carried out under the protection of argon, a water-cooled copper mold is used for cooling, then metal slag is stripped, calcium mixed with metal is cleaned, and a metallic dysprosium block is obtained, and the rest of the operation is the same as that in the step (1) in the embodiment 1.
The components of the prepared heavy rare earth alloy comprise 0.94% of tungsten, 0.16% of oxygen, 0.035% of carbon, 0.02% of calcium, 0.07% of iron, 97.9% of dysprosium, and the balance of impurities.
The other steps and process parameters were the same as in example 1.
Example 4
Example 4 is essentially the same as example 3, except that: example 4 in step (1), a molybdenum plate was used in place of the tungsten bar in step (1) of example 3, and a molybdenum crucible was used in place of the tungsten crucible in example 3. The components of the prepared heavy rare earth alloy comprise 0.96% of molybdenum, 0.17% of oxygen, 0.04% of carbon, 0.022% of calcium, 0.072% of iron, 97.8% of dysprosium, and the balance of impurities.
The other steps and process parameters were the same as in example 3.
Comparative example 1
Comparative example 1 is substantially the same as example 1 except that the pressure of the hydrogen absorption treatment in step (2) is 100KPa.G to 150 KPa.G. The components of the prepared heavy rare earth alloy comprise 0.91 percent of tungsten, 0.25 percent of oxygen, 0.048 percent of carbon, 0.023 percent of calcium, 0.072 iron, 98.5 percent of terbium and the balance of impurities. D (97) was 110.3 μm, and D (10) was 6.45. mu.m.
The other steps and process parameters were the same as in example 1.
Comparative example 2
Comparative example 2 is substantially the same as example 1 except that: in the step (1) of the comparative example 2, the commercially available terbium metal meeting the designation 094030 in GB/T20893 is directly adopted for the subsequent step (2), wherein the tungsten content is 0.08%, the oxygen content is 0.13%, the carbon content is 0.02%, and the balance is terbium. In the step (2), a rotary hydrogen crushing furnace is adopted for hydrogen absorption and dehydrogenation treatment, and the rest of the process is the same as that of the example 1.
The rare earth hydride powder D (97) obtained was 25.8 μm, D (10) was 3.25 μm, particle size was reduced, and powder oxygen content was 0.28%.
Comparative example 3
Comparative example 3 is substantially the same as example 2 except that: comparative example 3 in step (1), commercially available dysprosium metal meeting GB/T20893 is directly adopted to perform the subsequent step (2), wherein the content of tungsten is 0.1%, the content of oxygen is 0.15%, the content of carbon is 0.02%, and the balance is dysprosium.
The rest of the process and parameters were the same as in example 1.
The obtained rare earth hydride powder D (97) was 20.7 μm, D (10) was 1.25 μm, and the powder oxygen content was 0.35%.
The performance data of the neodymium-iron-boron magnets obtained in examples 1 to 4 and comparative examples 1 to 3 are shown in table 1.
TABLE 1
The technical features of the embodiment a may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments are not described, but should be considered as the scope of the present disclosure as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is specific and detailed, but not to be understood as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent should be subject to the appended claims.
Claims (8)
1. The preparation method of the neodymium iron boron magnet is characterized by comprising the following steps:
mixing rare earth hydrogenation metal powder with a solvent to obtain a suspension;
coating the suspension on the surface of a neodymium iron boron substrate to form a coating, and then carrying out grain boundary diffusion heat treatment to obtain a neodymium iron boron magnet;
the preparation method of the rare earth hydrogenation metal powder comprises the following steps:
(1) mixing and smelting the doped metal and the heavy rare earth metal to obtain a heavy rare earth alloy;
(2) crushing the heavy rare earth alloy, activating to obtain heavy rare earth alloy particles, sequentially carrying out first hydrogen absorption treatment, dehydrogenation treatment and second hydrogen absorption treatment on the heavy rare earth alloy particles, and cooling to obtain rare earth hydrogenated metal powder;
wherein, the heavy rare earth alloy comprises the following components in percentage by mass: 0.5% -1% of the doped metal, 97.5% -99.3% of the heavy rare earth metal and the balance of other impurities; the doped metal is selected from at least one of tungsten and molybdenum;
the pressure of the hydrogen in the first hydrogen absorption treatment and/or the second hydrogen absorption treatment is 150 KPa.G-200 KPa.G, and the temperature is not more than 400 ℃; the pressure of the dehydrogenation treatment is less than 20Pa, and the temperature is 600-750 ℃.
2. The method of manufacturing a neodymium-iron-boron magnet according to claim 1, wherein the heavy rare-earth alloy particles are replaced with the rare-earth hydride metal powder, and the first hydrogen absorption treatment, the dehydrogenation treatment, and the second hydrogen absorption treatment in step (2) are sequentially repeated N times, where N is an integer greater than or equal to 1.
3. The method for preparing the neodymium-iron-boron magnet according to any one of claims 1 to 2, wherein the vacuum degree of the activation treatment is less than 5Pa, the temperature is 650 ℃ to 850 ℃, and the time is 5min to 30 min.
4. The method for preparing the neodymium-iron-boron magnet according to any one of claims 1 to 2, wherein the step of mixed smelting specifically comprises the following steps:
placing the heavy rare earth metal and the doped metal in a crucible for melting refining, and cooling to obtain the heavy rare earth alloy; the heavy rare earth alloy comprises the following components in percentage by mass: 0.5% -1% of the doped metal, 97.5% -99.3% of the heavy rare earth metal and the balance of other impurities;
the crucible is made of at least one of tungsten and molybdenum.
5. The method for producing a neodymium-iron-boron magnet according to any one of claims 1 to 2, characterized in that the steps of the activation treatment, the first hydrogen absorption treatment, the dehydrogenation treatment, the second hydrogen absorption treatment and the cooling in step (2) are performed in a static hydrogen crusher; and/or
The heavy rare earth metal is at least one of terbium and dysprosium.
6. The method for preparing an ndfeb magnet according to any one of claims 1 to 2, wherein the cooling step is carried out in an inert gas at a pressure of 390kpa.g to 410 kpa.g.
7. The method for preparing the neodymium-iron-boron magnet according to any one of claims 1 to 2, wherein the thickness of the coating is 0.5mm to 3 mm.
8. A neodymium iron boron magnet manufactured by the method for manufacturing a neodymium iron boron magnet according to any one of claims 1 to 7.
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6613213B1 (en) * | 2000-03-27 | 2003-09-02 | Brookhaven Science Associates, Llc | Method for producing electrodes using microscale or nanoscale materials obtained from hydrogendriven metallurgical reactions |
| CN101542654A (en) * | 2007-03-30 | 2009-09-23 | Tdk株式会社 | Process for producing magnet |
| CN107492430A (en) * | 2017-08-09 | 2017-12-19 | 江西金力永磁科技股份有限公司 | A kind of neodymium iron boron magnetic body and preparation method thereof |
| KR20190125769A (en) * | 2018-04-30 | 2019-11-07 | 성림첨단산업(주) | Manufacturing method of rare earth sintered magnet |
| CN111768965A (en) * | 2020-05-06 | 2020-10-13 | 江西金力永磁科技股份有限公司 | Preparation method of annular radiation oriented magnet |
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Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6613213B1 (en) * | 2000-03-27 | 2003-09-02 | Brookhaven Science Associates, Llc | Method for producing electrodes using microscale or nanoscale materials obtained from hydrogendriven metallurgical reactions |
| CN101542654A (en) * | 2007-03-30 | 2009-09-23 | Tdk株式会社 | Process for producing magnet |
| CN107492430A (en) * | 2017-08-09 | 2017-12-19 | 江西金力永磁科技股份有限公司 | A kind of neodymium iron boron magnetic body and preparation method thereof |
| KR20190125769A (en) * | 2018-04-30 | 2019-11-07 | 성림첨단산업(주) | Manufacturing method of rare earth sintered magnet |
| CN111768965A (en) * | 2020-05-06 | 2020-10-13 | 江西金力永磁科技股份有限公司 | Preparation method of annular radiation oriented magnet |
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