JP6470816B2 - High coercive force Nd-Fe-B rare earth permanent magnet and manufacturing process thereof - Google Patents

Description

  The present invention belongs to the field of magnetic functional materials, and relates to a permanent magnet and a manufacturing process thereof. Specifically, the present invention relates to a high coercive force Nd—Fe—B rare earth permanent magnet and a manufacturing process thereof and parts including the same.

  Nd-Fe-B permanent magnets are permanent magnet materials with the strongest magnetism, and are widely used in fields such as electrical machinery, electronics, and medicine, and the fastest development in the world is expected. It is a permanent magnet material. However, Nd—Fe—B permanent magnets are inferior in temperature stability and difficult to use in a working environment of 150 ° C. or higher, so there is an obvious demerit that their use in high temperature fields is greatly limited. . In particular, with the rapid development of energy-saving hybrid vehicles in recent years, the demand for the quantity and temperature stability of Nd—Fe—B permanent magnets is also increasing, and the temperature stability of Nd—Fe—B permanent magnets is again attracting great attention. Have been bathed.

  Many studies have been conducted at home and abroad to improve the temperature stability of neodymium iron boron permanent magnets. Increasing the coercivity of the magnet by adding specific elements has been found to be one effective method. For example, adding a certain amount of heavy rare earth elements and transition metal elements Co, Cu, Zr, Ga, Al, Mn, Cr, Zn, Mo, V, Ti, Sn, etc. to the sintered Nd—Fe—B master alloy Thus, the coercive force of the magnet can be effectively improved and the temperature stability of the magnet can be improved. In particular, by adding heavy rare earth elements Tb and Dy, the coercive force of the magnet can be significantly improved.

However, the addition of Tb and Dy causes the following two serious problems. (1) Most of Tb and Dy enter the crystal grains and form a Tb ₂ Fe ₁₄ B or Dy ₂ Fe ₁₄ B compound together with Fe and B elements, and the magnetization of such a compound is the main of a neodymium iron boron permanent magnet. Since it is much lower than the phase Tb ₂ Fe ₁₄ B, the residual magnetic flux density and magnetic energy product of the material are greatly reduced. (2) Heavy rare earth elements such as Tb and Dy are expensive and scarce resources, the amount of storage is only 1/10 to 1/100 of Nd, and the number of mineral veins is limited to several places, and the production volume However, when producing a high coercivity sintered neodymium iron-boron magnet, it is usually required to add 5 wt% to 10 wt% of heavy rare earth elements. The demand is far beyond the limited resources.

  Currently, scholars at home and abroad improve the coercivity of magnets mainly by Dy diffusion treatment at grain boundaries. This method improves coercivity and can also greatly save the use of heavy rare earth elements. For example, Hitachi Metals provides a method for producing high coercivity sintered neodymium iron boron by vacuum evaporation, and Shin-Etsu Chemical Co., Ltd. provides a method for producing high coercivity sintered neodymium iron boron by coating method. doing. However, the above method has the following drawbacks. (1) The equipment is expensive. (2) The material utilization rate is low. (3) The thickness of the magnet is strictly required, and it is difficult to manufacture a magnet having a thickness larger than 10 mm, so that it cannot be used further. (4) Since the temperature at the time of manufacturing the Dy film is too high (1000 ° C. or higher), it adversely affects the microstructure of the magnet. (5) The uniformity of the film is difficult to control and it is difficult to realize industrialization.

  Therefore, in order to overcome the above disadvantages and obtain a high coercive force Nd—Fe—B rare earth permanent magnet and parts including the same, it is urgent to provide a new simple and economical manufacturing process.

In view of the problems existing in the prior art, the present invention provides a manufacturing process for producing a high coercivity sintered neodymium iron boron magnet at a low cost, that is, a technique for producing a rare earth film using an ionic liquid. Applied to the production of performance magnets, ^Rb film is grown on the magnet surface by this technology, then ^Rb element plated on the magnet surface by primary high temperature heat treatment is diffused into the magnet, and further by secondary low temperature tempering Provided is a process for uniformly distributing a rare earth-rich phase around a magnet and removing unbalanced structure and internal stress due to high temperature treatment. After being processed by this process, the internal coercivity of the magnet is significantly improved, so that a high coercive force Nd—Fe—B rare earth permanent magnet can be manufactured.

In order to achieve the above object, according to one aspect of the present invention,
1) R ^a FeMB in a general step in which the tempering step is omitted (where R ^a is at least one element selected from Nd, Pr, La, Ce, Sm, Sc, Y and Eu, and its content) Is 23 to 35 wt%, B is elemental boron, its content is 0.8 to 1.2 wt%, M is selected from transition metals other than Fe, and its content is 0 .01-5 wt%, the balance being Fe and inevitable impurities.) Manufacturing the magnet;
2) adding an ionic liquid whose main salt is R ^b Cl ₃ (wherein R ^b is at least one element selected from Tb, Dy, Gd and Ho) to the container;
3) producing an ^Rb film by a constant potential electrodeposition method, obtaining a magnet having an ^Rb film, the anode being pure metal ^Rb , and the cathode being ^a RaFeMB matrix;
4) A process for producing a Nd—Fe—B rare earth permanent magnet comprising the step of subjecting the magnet of step 3) to a tempering heat treatment to obtain a high coercive force Nd—Fe—B rare earth permanent magnet. To do.

  The general steps of step 1) in the manufacturing process include alloy melting, milling, forming and sintering steps.

In the R ^a FeMB magnet of step 1) in the manufacturing process, R ^a is at least one element selected from Nd, Pr, La, Ce, Sm, Sc, Y and Eu, and the content thereof is 23 -35 wt%, B is elemental boron, its content is 0.8-1.2 wt%, M is selected from transition metals other than Fe, and its content is 0.01 ˜5 wt% with the balance being Fe and inevitable impurities.

Preferably, ^{R a} is at least one element selected Nd, Pr, La, Ce, Sm and Sc, the content of 23~34wt%. More preferably, ^{R a} is at least one element selected Nd, Pr, from La and Ce, the content of 24~33wt%. Most preferably, ^{R a} is at least one element selected from Nd and Pr, the content of 25~32wt%. The inventors have found that a magnet having the above components and the content range has the most excellent performance, and that the magnetic properties are not significantly improved if the magnet is out of the above range.

  The ionic liquid of step 2) in the production process is selected from 1-ethyl-3-methylimidazolium tetrafluoroborate or 1-butyl-1-methylpyrrolidinium bis (trifluoromethylsulfonyl) imide. The above manufacturing process. The reason for selecting is that it is suitable for realizing industrialization because the price is reasonable and it can be manufactured stably.

The above manufacturing process the concentration of ^R b Cl ₃ is the major salts of the step 2) in the manufacturing process is 0.1 to 0.5 mol / L. The reason why the main salt is R ^b Cl ₃ is that it can be stably produced and is suitable for industrialization. By setting the concentration to 0.1 mol / L to 0.5 mol / L, it is possible to ensure that electrodeposition proceeds smoothly, and in the case of less than 0.1 mol / L and in the case of exceeding 0.5 mol / L, either Also adversely affects the stable progression of the reaction. From the viewpoint that R ^b Cl ₃ has the most excellent activity and is advantageous for the progress of electrodeposition, the concentration of RbCl ₃ that is a main salt is preferably in the range of 0.2 mol / L to 0.3 mol / L. is there.

Preferably, the concentration of R ^b Cl ₃ as the main salt is 0.15 to 0.4 mol / L. More preferably, the concentration of R ^b Cl ₃ which is a main salt is 0.2 to 0.3 mol / L. Most preferably, the concentration of R ^b Cl ₃ as the main salt is 0.25 to 0.3 mol / L. In one specific embodiment, the concentration of the major salt, R ^b Cl ₃ , is 0.26 mol / L.

The process parameters of the electrodeposition method in step 3) of the manufacturing process are as follows: current density is 500 to 10000 A · m ⁻² , electrodeposition time is 300 to 10000 s, and electrodeposition temperature is 20 to 70 ° C. .

In the present invention, the reason why the current density under a constant potential is 500 to 10,000 A · m ⁻² is that the electrodeposition rate is the fastest within this range. When the current density is less than 500 A · m ⁻² , the reaction rate is too slow, and when it exceeds 10000 A · m ⁻² , resources are wasted. From the viewpoint of the highest electrodeposition efficiency and the most rational use of resources, the current density is preferably in the range of 3500 to 6000 A · m ⁻² .

Preferably, the current density is 1000 to 8000 A · m ⁻² . More preferably, the current density is 2000 to 7000 A · m ⁻² . Most preferably, the current density is 3500 to 6000 A · m ⁻² .

In one specific embodiment, the current density is 4500 A · m ⁻² .

  In the present invention, the electrodeposition time is 300 s to 10000 s. The reason for setting the electrodeposition time to 300 to 10000 s is that a Dy film having an ideal thickness cannot be obtained when it is less than 300 s, while the thickness of the Dy film is too thick when it exceeds 10000 s, This is a waste of resources. From the viewpoint of obtaining a Dy film having an ideal thickness, the electrodeposition time is preferably in the range of 600 s to 3000 s.

  Preferably, the electrodeposition time is 400 to 8000 s. More preferably, the electrodeposition time is 500 to 6000 s. Most preferably, the electrodeposition time is 600-3500 s.

  In one specific embodiment, the electrodeposition time is 3000 s.

In the present invention, the reason for setting the electrodeposition temperature to 20 to 70 ° C. is that when the electrodeposition temperature is less than 20 ° C., the electrodeposition speed is reduced and the production efficiency is lowered, whereas the electrodeposition temperature exceeds 70 ° C. Is a waste of resources. From the viewpoint that R ^b Cl ₃ has the most excellent activity and is advantageous for the progress of electrodeposition, the electrodeposition temperature is preferably in the range of 40 to 60 ° C.

  Preferably, the electrodeposition temperature is 30 to 70 ° C. More preferably, the electrodeposition temperature is 30 to 60 ° C. Most preferably, the electrodeposition temperature is 40-60 ° C.

  In one specific embodiment, the electrodeposition temperature is 55 ° C.

The thickness of the ^Rb film manufactured in the step 3) in the manufacturing process is 0.1 to 15 μm. Preferably, the thickness of the ^Rb film is 1 to 15 μm. More preferably, the thickness of the ^Rb film is 2 to 12 μm. Most preferably, the ^Rb film has a thickness of 3 to 10 μm. When the film thickness is 10 μm or more, resources are wasted, and when the film thickness is less than 3 μm, significant improvement in magnet characteristics is hindered.

In one specific embodiment, the thickness of the ^Rb film produced in step 3) is 5 μm.

  The tempering heat treatment of step 4) in the manufacturing process includes primary high temperature tempering and secondary low temperature tempering.

  The temperature of the primary high-temperature tempering heat treatment in the production process is 700 to 1000 ° C., the treatment time is 1 to 100 h, and the cooling rate is 50 to 300 ° C./min. Preferably, the temperature of the primary high-temperature tempering heat treatment is 750 to 950 ° C., the treatment time is 1 to 50 h, and the cooling rate is 80 to 280 ° C./min. More preferably, the temperature of the primary high-temperature tempering heat treatment is 750 to 900 ° C, the treatment time is 2 to 20 hours, and the cooling rate is 120 to 260 ° C / min. Most preferably, the temperature of the primary high-temperature tempering heat treatment is 800 to 900 ° C., the treatment time is 2 to 10 hours, and the cooling rate is 150 to 250 ° C./min.

The primary tempering action is to diffuse the elements in the ^Rb film plated on the magnet surface into the magnet. When the temperature is less than 800 ° C. and the time is less than 2 h, the diffusion of elements in the ^Rb film becomes insufficient, and the effect of the present invention cannot be achieved. Further, if the temperature is higher than 900 ° C. and the time is longer than 10 hours, production efficiency is adversely affected. Cooling at 50 to 300 ° C./min contributes to maintaining a high coercivity microstructure. From the viewpoint of improving the magnet characteristics, it is preferably 150 to 250 ° C./min. If it is outside the scope of the present invention, the effect of the present invention cannot be achieved.

  In one specific embodiment, the temperature of the primary high temperature tempering heat treatment is 800 ° C., the treatment time is 4 h, and the cooling rate is 200 ° C./min.

  The temperature of the secondary low-temperature tempering heat treatment in the manufacturing process is 400 to 655 ° C., the treatment time is 1 to 10 hours, and the cooling rate is 50 to 200 ° C./min. Preferably, the temperature of the secondary low-temperature tempering heat treatment is 420 to 630 ° C., the treatment time is 1 to 8 hours, and the cooling rate is 60 to 180 ° C./min. More preferably, the temperature of the secondary low-temperature tempering heat treatment is 440 to 590 ° C., the treatment time is 2 to 7 hours, and the cooling rate is 80 to 160 ° C./min. Most preferably, the temperature of the secondary low-temperature tempering heat treatment is 480 to 560 ° C., the treatment time is 2 to 6 hours, and the cooling rate is 100 to 150 ° C./min.

  The effect of secondary tempering is to distribute the rare earth-rich phase uniformly at the grain boundaries and to remove the unbalanced structure and internal stress caused by the high temperature treatment. When the temperature is less than 480 ° C. and the time is less than 2 h, the distribution of the rare earth-rich phase at the grain boundaries becomes non-uniform, and the effect of the present invention cannot be achieved. If the temperature is higher than 560 ° C. and the time is longer than 6 h, production efficiency is adversely affected. When the cooling rate is less than 50 ° C./min and when it exceeds 200 ° C./min, both are disadvantageous for uniform distribution at the grain boundaries of the rare earth-rich phase. From the viewpoint of improving the magnet characteristics, it is preferably 100 to 150 ° C./min.

  In one specific embodiment, the temperature of the secondary low-temperature tempering heat treatment is 520 ° C., the treatment time is 4 h, and the cooling rate is 120 ° C./min.

In the manufacturing process of the present invention, the magnet manufactured in step (1) omits the tempering process as compared with the conventional manufacturing process. The inventors have found that steps (1) and (4) have improved productivity and greatly improved the coercive force of the magnet. The tempering heat treatment is divided into two stages. The primary tempering action is to diffuse the ^Rb element plated on the magnet surface to the inside of the magnet, and the secondary tempering action is to cause the rare earth-rich phase to pass through the grain boundary. And uniformly removing the unbalanced structure and internal stress caused by the high-temperature treatment. By steps (2) and (3), a uniform and dense ^Rb film can be simultaneously formed on the six surfaces of the magnet, and if the electrodeposition temperature is 20 to 70 ° C., electrodeposition can proceed smoothly. Since the temperature is much lower than 1000 ° C. required for molten salt electrolysis, production efficiency can be greatly improved. With the combination of steps (1), (2), (3) and (4), the problem is that a high coercive force magnet can be manufactured and a magnet having a thickness greater than 10 mm cannot be manufactured by the Dy diffusion treatment method at the grain boundary. Can be solved.

  In another aspect of the present invention, there is provided an Nd—Fe—B rare earth permanent magnet manufactured by the above manufacturing process.

In the Nd—Fe—B rare earth permanent magnet, the chemical formula of the rare earth permanent magnet is R ^a R ^b FeMB (wherein R ^a is at least selected from Nd, Pr, La, Ce, Sm, Sc, Y and Eu) It is one element, its content is 23 to 35 wt%, ^Rb is at least one element selected from Tb, Dy, Gd and Ho, and its content is 0.1 to 3 wt% B is elemental boron, its content is 0.8-1.2 wt%, M is selected from transition metals other than Fe, and its content is 0.01-5 wt% And the balance is Fe and inevitable impurities).

Preferably, ^{R a} is at least one element selected Nd, Pr, La, Ce, Sm and Sc, the content of 23~34wt%. More preferably, ^{R a} is at least one element selected Nd, Pr, from La and Ce, the content of 24~33wt%. Most preferably, ^{R a} is at least one element selected from Nd and Pr, the content of 25~32wt%.

The inventors have shown that the element ^Ra is preferably Nd and Pr, and the content thereof is 25 to 32 wt%. When the content is within this range, the magnetic properties are most excellent. It was found that Rb is not significant, and ^Rb is preferably Tb or Dy, and its content is preferably 0.2 to 2 wt%. According to the theoretical calculation, in the present invention, it is possible to achieve the performance at the usage amount of 10 wt% by the conventional method with the usage amount of only 2 wt%, and the heavy rare earth element R ^b can be achieved while ensuring high performance. The amount used can be greatly reduced. The reason why Tb and Dy are preferred is that the compound formed from Tb and Dy has a higher coercive force. When the simple substance B is in the range of 0.8 to 1.2 wt%, the magnet characteristics are the best, but if it is out of this range, the effect of the present invention cannot be achieved. When M is a transition metal other than Fe and the content thereof is in the range of 0.01 to 5 wt%, the magnet characteristics are most excellent. However, when the content is out of this range, the effect of the present invention is achieved. I can't do that.

  The thickness of the rare earth permanent magnet in the Nd—Fe—B rare earth permanent magnet is 0.1 to 20 mm. Preferably, it is 1-15 mm. The magnet to be manufactured has a thickness of 0.1 to 20 mm, preferably 1 to 15 mm. The reason is that when the thickness is less than 1 mm, the field of use is limited, and when the thickness is 15 mm or more, the improvement of the coercive force is not remarkable.

^Rb in the Nd—Fe—B rare earth permanent magnet has a concentration in the magnet grain boundary phase higher than the concentration in the magnet main phase.

  Finally, the present invention further provides a component comprising the above Nd—Fe—B rare earth permanent magnet.

  The present invention has the following advantageous effects over the prior art.

  (1) A technique for producing a rare earth film using an ionic liquid is used for forming a magnet, and the produced film has good uniformity and easy control of the film thickness, and its operation is simple. Low cost, environmentally friendly and industrialization is possible.

(2) The manufacturing process of the high coercive force magnet is optimized, and an ^Rb film is manufactured by an electrodeposition method (a method of manufacturing a rare earth film using an ionic liquid) prior to the conventional tempering heat treatment, and then tempering. By heat treatment, a high coercivity magnet was obtained and the production efficiency was improved.

  (3) The electrodeposition method (a method for producing a rare earth film using an ionic liquid) is used for film formation of a magnet, and the most appropriate ratio and the ratio of Tb and Dy in the magnet main phase are appropriately controlled. The best magnetic properties were obtained, the coercive force was greatly improved, and the magnetic energy product and residual magnetic flux density were improved.

By (4) electrodeposition method (method for producing a rare earth film using an ionic liquid) in producing a R ^b films, relatively good R ^b film adhesion is formed in the six sides of the magnet, the The invention is useful for producing a high coercivity magnet of 10 mm or more.

  (5) The use of rare earth metals can be reduced because the use of heavy rare earth elements Tb and Dy can be reduced, rare earth metals can be used, the coercive force can be greatly improved, and the amount of magnets used can be effectively reduced. The purpose of saving the amount can be realized.

It is an X-ray diffraction pattern of the Dy film manufactured by the present invention.

  Hereinafter, the present invention will be further described with reference to specific embodiments. In addition, these Examples are only for demonstrating this invention, and the scope of the present invention is not limited to these. Those skilled in the art who have read the contents of the present invention can make various changes or modifications to the present invention, and it is understood that these forms are within the scope of the claims of the present application. Should.

  The present invention will be better understood through the following examples, but the scope of the present invention is not limited thereto.

The comparative example of this example is a magnet manufactured by adding ^Rb metal (the same amount as the amount of ^Rb used in the present invention) by a conventional method. In the conventional method, the ^Rb metal is added when the mother alloy is melted, whereas in the present invention, after the magnet is manufactured, the electrodeposition method (rare earth film using ionic liquid is used). The ^Rb film is obtained by a method for producing the ^Rb metal, and the ^Rb metal is diffused into the magnet by a two-step heat treatment. The magnets produced according to the present invention have significantly improved magnetic properties and greatly saved heavy rare earth element usage.

Example 1
The manufacturing method of this example is as follows. The invention produced an R ^a FeMB magnet by steps of alloy melting, powder control, molding, and sintering, and obtained a 10 × 10 × 7 (7 is c-axis direction, unit mm) magnet by wire cutting. ^Rb was plated on the surface of the magnet according to the present invention. The specific parameters adopted in the electrodeposition method (method for producing a rare earth film using an ionic liquid) are as follows: the ionic liquid is 1-ethyl-3-methylimidazolium tetrafluoroborate and the main salt is TbCl. The concentration of ₃ is 0.2 mol / L, the electrodeposition temperature is 20 ° C., the current density at a constant potential is 6000 A · m ⁻² , and after 2000 seconds from the start of film formation, the film formation is stopped. The film thickness is 3.0 μm. The sample was then subjected to a two-step heat treatment. In the primary heat treatment process, the temperature is kept at 800 ° C. for 1 hour and then cooled, and the cooling rate is 50 ° C./h. In the secondary heat treatment process, the temperature is kept at 400 ° C. for 1 hour and the cooling rate is 50 ° C./h. . After cooling to room temperature, the magnetic properties of the sample were measured. For comparison, a magnet was manufactured by adding Tb by a conventional melting method. The magnet characteristics are shown in Table 1-1. The composition components of this magnet were analyzed by ICP analysis and are shown in Table 1-2. Magnets were produced with this composition by conventional methods.

Example 2
The manufacturing method of this example is as follows. The invention produced an R ^a FeMB magnet by the steps of alloy melting, powder control, molding and sintering, and obtained a 10 × 10 × 8 (8 is c-axis direction, unit mm) magnet by wire cutting. ^Rb was plated on the surface of the magnet according to the present invention. The specific parameters adopted in the electrodeposition method (method for producing a rare earth film using an ionic liquid) are as follows: the ionic liquid is 1-ethyl-3-methylimidazolium tetrafluoroborate and the main salt is TbCl. The concentration of ₃ is 0.2 mol / L, the electrodeposition temperature is 70 ° C., the current density at a constant potential is 6000 A · m ⁻² , and after 2000 seconds from the start of film formation, the film formation is stopped. The film thickness is 3.0 μm. The sample was then subjected to a two-step heat treatment. In the primary heat treatment process, the temperature is kept at 800 ° C. for 100 hours and then cooled, and the cooling rate is 300 ° C./h. In the secondary heat treatment process, the temperature is kept at 655 ° C. for 10 hours and the cooling rate is 200 ° C./h. After cooling to room temperature, the magnetic properties of the sample were measured. For comparison, a magnet was manufactured by adding Tb by a conventional melting method. The magnet characteristics are shown in Table 2-1. The composition components of this magnet were analyzed by ICP analysis and are shown in Table 2-2. Magnets were produced with this composition by conventional methods.

Example 3
The manufacturing method of this example is as follows. The invention produced an R ^a FeMB magnet by the steps of alloy melting, powder control, molding, and sintering, and obtained a magnet of 10 × 10 × 1 (1 is c-axis direction, unit mm) by wire cutting. ^Rb was plated on the surface of the magnet according to the present invention. Specific parameters adopted by the electrodeposition method (method for producing a rare earth film using an ionic liquid) are as follows: the ionic liquid is 1-butyl-1-methylpyrrolidinium bis (trifluoromethylsulfonyl) imide, The concentration of TbCl ₃ which is a simple salt is 0.2 mol / L, the electrodeposition temperature is 40 ° C., the current density at a constant potential is 3000 A · m ⁻² , and after 1800 seconds from the start of film formation The film formation was stopped, and the film thickness was 5.0 μm. The sample was then subjected to a two-step heat treatment. In the primary heat treatment process, the temperature is kept at 700 ° C. for 10 hours and then cooled, and the cooling rate is 150 ° C./h. In the secondary heat treatment process, the temperature is kept at 480 ° C. for 2 hours and the cooling rate is 150 ° C./h. After cooling to room temperature, the magnetic properties of the sample were measured. For comparison, a magnet was manufactured by adding Tb by a conventional melting method. Magnet characteristics are shown in Table 3-1. The composition components of this magnet were analyzed by ICP analysis, and are shown in Table 3-2. Magnets were produced with this composition by conventional methods.

Example 4
The manufacturing method of this example is as follows. The invention produced an R ^a FeMB magnet by the steps of alloy melting, powder control, molding, and sintering, and obtained a 10 × 10 × 20 (20 is c-axis direction, unit mm) magnet by wire cutting. ^Rb was plated on the surface of the magnet according to the present invention. Specific parameters adopted by the electrodeposition method (method for producing a rare earth film using an ionic liquid) are as follows: the ionic liquid is 1-butyl-1-methylpyrrolidinium bis (trifluoromethylsulfonyl) imide, The concentration of DyCl ₃ , which is a simple salt, is 0.2 mol / L, the electrodeposition temperature is 80 ° C., the current density at a constant potential is 3000 A · m ⁻² , and after 1800 seconds from the start of film formation The film formation was stopped, and the film thickness was 5.0 μm. The sample was then subjected to a two-step heat treatment. In the primary heat treatment process, the temperature is kept at 820 ° C. for 3 hours and then cooled, and the cooling rate is 200 ° C./h. In the secondary heat treatment process, the temperature is kept at 500 ° C. for 4 hours and the cooling rate is 120 ° C./h. After cooling to room temperature, the magnetic properties of the sample were measured. For comparison, a magnet was manufactured by adding Dy by a conventional melting method. Magnet characteristics are shown in Table 4-1. The composition components of this magnet were analyzed by ICP analysis and are shown in Table 4-2. Magnets were produced with this composition by conventional methods.

Example 5
The manufacturing method of this example is as follows. The invention produced an R ^a FeMB magnet by steps of alloy melting, powder control, molding, and sintering, and obtained a 10 × 10 × 15 (15 is c-axis direction, unit mm) magnet by wire cutting. ^Rb was plated on the surface of the magnet according to the present invention. Specific parameters adopted by the electrodeposition method (method for producing a rare earth film using an ionic liquid) are as follows: the ionic liquid is 1-butyl-1-methylpyrrolidinium bis (trifluoromethylsulfonyl) imide, The concentration of GdCl ₃ , which is a simple salt, is 0.2 mol / L, the electrodeposition temperature is 70 ° C., the current density at a constant potential is 3000 A · m ⁻² , 600 seconds after the start of film formation The film formation was stopped, and the film thickness was 1.0 μm. The sample was then subjected to a two-step heat treatment. In the primary heat treatment process, the temperature is kept at 1000 ° C. for 2 hours and then cooled, and the cooling rate is 250 ° C./h. In the secondary heat treatment process, the temperature is kept at 560 ° C. for 6 hours and the cooling rate is 100 ° C./h. After cooling to room temperature, the magnetic properties of the sample were measured. For comparison, a magnet was manufactured by adding Gd by a conventional melting method. The magnet characteristics are shown in Table 5-1. The composition components of this magnet were analyzed by ICP analysis and are shown in Table 5-2. Magnets were produced with this composition by conventional methods.

Example 6
The manufacturing method of this example is as follows. The invention produced an R ^a FeMB magnet by the steps of alloy melting, powder control, molding, and sintering, and obtained a magnet of 10 × 10 × 5 (5 is c-axis direction, unit mm) by wire cutting. ^Rb was plated on the surface of the magnet according to the present invention. Specific parameters adopted by the electrodeposition method (method for producing a rare earth film using an ionic liquid) are as follows: the ionic liquid is 1-butyl-1-methylpyrrolidinium bis (trifluoromethylsulfonyl) imide, The concentration of DyCl ₃ , which is a simple salt, is 0.1 mol / L, the electrodeposition temperature is 60 ° C., the current density at a constant potential is 6000 A · m ⁻² , and 3000 seconds after the start of film formation The film formation was stopped and the film thickness was 10.0 μm. The sample was then subjected to a two-step heat treatment. In the primary heat treatment process, the temperature is kept at 850 ° C. for 4 hours and then cooled, and the cooling rate is 220 ° C./h. In the secondary heat treatment process, the temperature is kept at 540 ° C. for 4 hours and the cooling rate is 140 ° C./h. After cooling to room temperature, the magnetic properties of the sample were measured. For comparison, a magnet was manufactured by adding Dy by a conventional melting method. The magnet characteristics are shown in Table 6-1. The composition components of this magnet were analyzed by ICP analysis and are shown in Table 6-2. Magnets were produced with this composition by conventional methods.

Example 7
The manufacturing method of this example is as follows. The invention produced an R ^a FeMB magnet by the steps of alloy melting, powder control, molding, and sintering, and obtained a magnet of 10 × 10 × 5 (5 is c-axis direction, unit mm) by wire cutting. ^Rb was plated on the surface of the magnet according to the present invention. Specific parameters adopted by the electrodeposition method (method for producing a rare earth film using an ionic liquid) are as follows: the ionic liquid is 1-butyl-1-methylpyrrolidinium bis (trifluoromethylsulfonyl) imide, The concentration of TbCl ₃ , which is a simple salt, is 0.5 mol / L, the electrodeposition temperature is 50 ° C., the current density at a constant potential is 6000 A · m ⁻² , and after 4500 seconds from the start of film formation The film formation was stopped and the film thickness was 10.0 μm. The sample was then subjected to a two-step heat treatment. In the primary heat treatment process, the temperature is kept at 850 ° C. for 4 hours and then cooled, and the cooling rate is 220 ° C./h. In the secondary heat treatment process, the temperature is kept at 540 ° C. for 4 hours and the cooling rate is 140 ° C./h. After cooling to room temperature, the magnetic properties of the sample were measured. For comparison, a magnet was manufactured by adding Tb by a conventional melting method. Magnet characteristics are shown in Table 7-1. The composition components of this magnet were analyzed by ICP analysis and are shown in Table 7-2. Magnets were produced with this composition by conventional methods.

Example 8
The manufacturing method of this example is as follows. The invention manufactures ^a R ^a FeMB magnet by the steps of alloy melting, powder control, molding, and sintering, and 10 × 10 × 0.1 (0.1 is c-axis direction, unit mm) magnet by wire cutting. Got. ^Rb was plated on the surface of the magnet according to the present invention. Specific parameters adopted by the electrodeposition method (method for producing a rare earth film using an ionic liquid) are as follows: the ionic liquid is 1-butyl-1-methylpyrrolidinium bis (trifluoromethylsulfonyl) imide, The concentration of DyCl ₃ , which is a simple salt, is 0.4 mol / L, the electrodeposition temperature is 70 ° C., the current density at a constant potential is 3500 A · m ⁻² , and after 300 seconds from the start of film formation The film formation was stopped, and the film thickness was 1.0 μm. The sample was then subjected to a two-step heat treatment. In the primary heat treatment process, the temperature is kept at 830 ° C. for 5 hours and then cooled, and the cooling rate is 240 ° C./h. In the secondary heat treatment process, the temperature is kept at 560 ° C. for 3 hours and the cooling rate is 120 ° C./h. After cooling to room temperature, the magnetic properties of the sample were measured. For comparison, a magnet was manufactured by adding Dy by a conventional melting method. The magnet characteristics are shown in Table 8-1. The composition components of this magnet were analyzed by ICP analysis and are shown in Table 8-2. Magnets were produced with this composition by conventional methods.

Example 9
The manufacturing method of this example is as follows. The invention manufactures R ^a FeMB magnets in the steps of alloy melting, powder control, molding, and sintering, and 10 × 10 × 3.5 (3.5 is c-axis direction, unit mm) magnets by wire cutting. Got. ^Rb was plated on the surface of the magnet according to the present invention. Specific parameters adopted by the electrodeposition method (method for producing a rare earth film using an ionic liquid) are as follows: the ionic liquid is 1-butyl-1-methylpyrrolidinium bis (trifluoromethylsulfonyl) imide, The concentration of TbCl ₃ , which is a simple salt, is 0.26 mol / L, the electrodeposition temperature is 55 ° C., the current density at a constant potential is 5000 A · m ⁻² , and after 1300 seconds from the start of film formation The film formation was stopped, and the film thickness was 8.0 μm. The sample was then subjected to a two-step heat treatment. In the primary heat treatment process, the temperature is kept at 870 ° C. for 6 hours and then cooled, and the cooling rate is 180 ° C./h. In the secondary heat treatment process, the temperature is kept at 490 ° C. for 5 hours and the cooling rate is 130 ° C./h. After cooling to room temperature, the magnetic properties of the sample were measured. For comparison, a magnet was manufactured by adding Tb by a conventional melting method. Magnet characteristics are shown in Table 9-1. The composition components of this magnet were analyzed by ICP analysis and are shown in Table 9-2. Magnets were produced with this composition by conventional methods.

Example 10
The manufacturing method of this example is as follows. The invention produced an R ^a FeMB magnet by the steps of alloy melting, powder control, molding and sintering, and obtained a magnet of 10 × 10 × 10 (10 is c-axis direction, unit mm) by wire cutting. ^Rb was plated on the surface of the magnet according to the present invention. Specific parameters adopted by the electrodeposition method (method for producing a rare earth film using an ionic liquid) are HoBr, which is a main salt, where the ionic liquid is 1-ethyl-3-methylimidazolium tetrafluoroborate. The concentration of ₃ is 0.24 mol / L, the electrodeposition temperature is 80 ° C., the current density at a constant potential is 3000 A · m ⁻² , and after 1600 seconds from the start of film formation, the film formation is stopped. The film thickness is 5.0 μm. The sample was then subjected to a two-step heat treatment. In the primary heat treatment process, the temperature is kept at 890 ° C. for 3.5 hours and then cooled, and the cooling rate is 225 ° C./h. In the secondary heat treatment process, the temperature is kept at 540 ° C. for 5 hours and the cooling rate is 110 ° C./h. is there. After cooling to room temperature, the magnetic properties of the sample were measured. For comparison, a magnet was manufactured by adding Ho by a conventional melting method. The magnet characteristics are shown in Table 10-1. The composition components of this magnet were analyzed by ICP analysis and are shown in Table 10-2. Magnets were produced with this composition by conventional methods.

Example 11
The manufacturing method of this example is as follows. The invention produced an R ^a FeMB magnet by the steps of alloy melting, powder control, molding and sintering, and obtained a 10 × 10 × 8 (8 is c-axis direction, unit mm) magnet by wire cutting. ^Rb was plated on the surface of the magnet according to the present invention. The specific parameters adopted by the electrodeposition method (method for producing a rare earth film using an ionic liquid) are as follows: the ionic liquid is 1-ethyl-3-methylimidazolium tetrafluoroborate and the main salt is GdCl. ₃ concentration is 0.25 mol / L, electrodeposition temperature is 75 ° C., current density under constant potential is 4500 A · m ⁻² , and after 3000 seconds from the start of film formation, the film formation is stopped. The film thickness is 10.0 μm. The sample was then subjected to a two-step heat treatment. In the primary heat treatment process, the temperature is kept at 750 ° C. for 1.5 hours and then cooled, and the cooling rate is 275 ° C./h. In the secondary heat treatment process, the temperature is kept at 600 ° C. for 8 hours and the cooling rate is 160 ° C./h. is there. After cooling to room temperature, the magnetic properties of the sample were measured. For comparison, a magnet was manufactured by adding Gd by a conventional melting method. The magnet characteristics are shown in Table 11-1. The composition components of this magnet were analyzed by ICP analysis and are shown in Table 11-2. Magnets were produced with this composition by conventional methods.

Example 12
The manufacturing method of this example is as follows. The invention produced an R ^a FeMB magnet by the steps of alloy melting, powder control, molding and sintering, and obtained a 10 × 10 × 3 (3 is c-axis direction, unit mm) magnet by wire cutting. ^Rb was plated on the surface of the magnet according to the present invention. The specific parameters adopted in the electrodeposition method (method for producing a rare earth film using an ionic liquid) are: 1y-ethyl-3-methylimidazolium tetrafluoroborate as the ionic liquid, and DyCl, which is the main salt ₃ concentration is 0.28 mol / L, electrodeposition temperature is 65 ° C., current density under constant potential is 4000 A · m ⁻² , and after 3000 seconds from the start of film formation, the film formation is stopped. The film thickness is 8.0 μm. The sample was then subjected to a two-step heat treatment. In the primary heat treatment process, the temperature is kept at 890 ° C. for 3.5 hours and then cooled, and the cooling rate is 225 ° C./h. In the secondary heat treatment process, the temperature is kept at 540 ° C. for 5 hours and the cooling rate is 110 ° C./h. is there. After cooling to room temperature, the magnetic properties of the sample were measured. For comparison, a magnet was manufactured by adding Dy by a conventional melting method. The magnet characteristics are shown in Table 12-1. The composition components of this magnet were analyzed by ICP analysis and are shown in Table 12-2. Magnets were produced with this composition by conventional methods.

Example 13
The manufacturing method of this example is as follows. The invention produced an R ^a FeMB magnet by the steps of alloy melting, powder control, molding and sintering, and obtained a 10 × 10 × 2 (2 is c-axis direction, unit mm) magnet by wire cutting. ^Rb was plated on the surface of the magnet according to the present invention. The specific parameters adopted in the electrodeposition method (method for producing a rare earth film using an ionic liquid) are: 1y-ethyl-3-methylimidazolium tetrafluoroborate as the ionic liquid, and DyCl, which is the main salt ₃ concentration is 0.25 mol / L, electrodeposition temperature is 50 ° C., current density under constant potential is 4500 A · m ⁻² , and after 400 seconds from the start of film formation, the film formation is stopped. The film thickness is 1.5 μm. The sample was then subjected to a two-step heat treatment. In the primary heat treatment process, the temperature is kept at 880 ° C. for 3.5 hours and then cooled, and the cooling rate is 205 ° C./h. In the secondary heat treatment process, the temperature is kept at 510 ° C. for 3 hours and the cooling rate is 130 ° C./h. is there. After cooling to room temperature, the magnetic properties of the sample were measured. For comparison, a magnet was manufactured by adding Dy by a conventional melting method. The magnet characteristics are shown in Table 13-1. The composition components of this magnet were analyzed by ICP analysis and are shown in Table 13-2. Magnets were produced with this composition by conventional methods.

Example 14
The manufacturing method of this example is as follows. The invention manufactures ^a R ^a FeMB magnet through the steps of alloy melting, powder control, molding and sintering, and 10 × 10 × 7.5 (7.5 is c-axis direction, unit mm) magnet by wire cutting. Got. ^Rb was plated on the surface of the magnet according to the present invention. The specific parameters adopted in the electrodeposition method (method for producing a rare earth film using an ionic liquid) are: 1y-ethyl-3-methylimidazolium tetrafluoroborate as the ionic liquid, and DyCl, which is the main salt ₃ concentration is 0.25 mol / L, electrodeposition temperature is 75 ° C., current density under constant potential is 5000 A · m ⁻² , and after 4000 seconds from the start of film formation, the film formation is stopped. The film thickness is 10 μm. The sample was then subjected to a two-step heat treatment. In the primary heat treatment process, the temperature is kept at 890 ° C. for 3.5 hours and then cooled, and the cooling rate is 225 ° C./h. In the secondary heat treatment process, the temperature is kept at 540 ° C. for 5 hours and the cooling rate is 110 ° C./h. is there. After cooling to room temperature, the magnetic properties of the sample were measured. For comparison, a magnet was manufactured by adding Dy by a conventional melting method. The magnet characteristics are shown in Table 14-1. The composition components of this magnet were analyzed by ICP analysis and are shown in Table 14-2. Magnets were produced with this composition by conventional methods.

Example 15
The manufacturing method of this example is as follows. The invention manufactures R ^a FeMB magnets in the steps of alloy melting, powder control, molding, and sintering, and 10 × 10 × 0.5 (0.5 is c-axis direction, unit mm) magnets by wire cutting. Got. ^Rb was plated on the surface of the magnet according to the present invention. The specific parameters adopted in the electrodeposition method (method for producing a rare earth film using an ionic liquid) are: 1y-ethyl-3-methylimidazolium tetrafluoroborate as the ionic liquid, and DyCl, which is the main salt ₃ concentration is 0.20 mol / L, electrodeposition temperature is 60 ° C., current density under constant potential is 2000 A · m ⁻² , and after 2500 seconds from the start of film formation, the film formation is stopped. The film thickness is 4 μm. The sample was then subjected to a two-step heat treatment. In the primary heat treatment process, the temperature is kept at 810 ° C. for 4.5 hours and then cooled, and the cooling rate is 235 ° C./h. In the secondary heat treatment process, the temperature is kept at 530 ° C. for 4.5 hours and the cooling rate is 130 ° C./hour. h. After cooling to room temperature, the magnetic properties of the sample were measured. For comparison, a magnet was manufactured by adding Dy by a conventional melting method. The magnet characteristics are shown in Table 15-1. The composition components of this magnet were analyzed by ICP analysis and are shown in Table 15-2. Magnets were produced with this composition by conventional methods.

Example 16
The manufacturing method of this example is as follows. The invention manufactures ^a R ^a FeMB magnet by the steps of alloy melting, powder control, molding, and sintering, and 10 × 10 × 2.5 (2.5 is c-axis direction, unit mm) magnet by wire cutting. Got. ^Rb was plated on the surface of the magnet according to the present invention. The specific parameters adopted in the electrodeposition method (method for producing a rare earth film using an ionic liquid) are as follows: the ionic liquid is 1-ethyl-3-methylimidazolium tetrafluoroborate and the main salt is TbCl. ₃ concentration is 0.25 mol / L, electrodeposition temperature is 55 ° C., current density at a constant potential is 4500 A · m ⁻² , and after 3000 seconds from the start of film formation, the film formation is stopped. The film thickness is 5.0 μm. The sample was then subjected to a two-step heat treatment. In the primary heat treatment process, the temperature is kept at 850 ° C. for 5.5 hours and then cooled, and the cooling rate is 175 ° C./h. In the secondary heat treatment process, the temperature is kept at 550 ° C. for 3.5 hours and the cooling rate is 120 ° C./hour. h. After cooling to room temperature, the magnetic properties of the sample were measured. For comparison, a magnet was manufactured by adding Tb by a conventional melting method. The magnet characteristics are shown in Table 16-1. The composition components of this magnet were analyzed by ICP analysis and shown in Table 16-2. Magnets were produced with this composition by conventional methods.

Example 17
The manufacturing method of this example is as follows. The invention produced an R ^a FeMB magnet by the steps of alloy melting, powder control, molding, and sintering, and obtained a magnet of 10 × 10 × 12 (12 is c-axis direction, unit mm) by wire cutting. ^Rb was plated on the surface of the magnet according to the present invention. Specific parameters adopted by the electrodeposition method (method for producing a rare earth film using an ionic liquid) are as follows: the ionic liquid is 1-butyl-1-methylpyrrolidinium bis (trifluoromethylsulfonyl) imide, The concentration of TbCl ₃ , which is a simple salt, is 0.3 mol / L, the electrodeposition temperature is 50 ° C., the current density at a constant potential is 1000 A · m ⁻² , and 10000 seconds after the start of film formation The film formation was stopped, and the film thickness was 15.0 μm. The sample was then subjected to a two-step heat treatment. In the primary heat treatment process, the temperature is kept at 855 ° C. for 8 hours and then cooled, and the cooling rate is 185 ° C./h. In the secondary heat treatment process, the temperature is kept at 540 ° C. for 4.5 hours and the cooling rate is 130 ° C./h. is there. After cooling to room temperature, the magnetic properties of the sample were measured. For comparison, a magnet was manufactured by adding Tb by a conventional melting method. The magnet characteristics are shown in Table 17-1. The composition components of this magnet were analyzed by ICP analysis and are shown in Table 17-2. Magnets were produced with this composition by conventional methods.

Example 18
The manufacturing method of this example is as follows. The invention produced an R ^a FeMB magnet by the steps of alloy melting, powder control, molding, and sintering, and obtained a magnet of 10 × 10 × 12 (12 is c-axis direction, unit mm) by wire cutting. ^Rb was plated on the surface of the magnet according to the present invention. Specific parameters adopted by the electrodeposition method (method for producing a rare earth film using an ionic liquid) are as follows: the ionic liquid is 1-butyl-1-methylpyrrolidinium bis (trifluoromethylsulfonyl) imide, The concentration of DyCl ₃ , which is a simple salt, is 0.3 mol / L, the electrodeposition temperature is 70 ° C., the current density at a constant potential is 10,000 A · m ⁻² , 3000 seconds after the start of film formation The film formation was stopped, and the film thickness was 6.0 μm. The sample was then subjected to a two-step heat treatment. In the primary heat treatment process, the temperature is kept at 875 ° C. for 4 hours and then cooled, and the cooling rate is 175 ° C./h. In the secondary heat treatment process, the temperature is kept at 500 ° C. for 3.5 hours and the cooling rate is 140 ° C./h. is there. After cooling to room temperature, the magnetic properties of the sample were measured. For comparison, a magnet was manufactured by adding Dy by a conventional melting method. The magnet characteristics are shown in Table 18-1. The composition components of this magnet were analyzed by ICP analysis and are shown in Table 18-2. Magnets were produced with this composition by conventional methods.

Example 19
The manufacturing method of this example is as follows. The invention manufactures R ^a FeMB magnets in the steps of alloy melting, powder control, molding, and sintering, and 10 × 10 × 4.5 (4.5 is c-axis direction, unit mm) magnets by wire cutting. Got. ^Rb was plated on the surface of the magnet according to the present invention. Specific parameters adopted by the electrodeposition method (method for producing a rare earth film using an ionic liquid) are as follows: the ionic liquid is 1-butyl-1-methylpyrrolidinium bis (trifluoromethylsulfonyl) imide, The concentration of DyCl ₃ , which is a simple salt, is 0.3 mol / L, the electrodeposition temperature is 55 ° C., the current density under a constant potential is 5000 A · m ⁻² , and after 2000 seconds from the start of film formation The film formation was stopped, and the film thickness was 8.0 μm. The sample was then subjected to a two-step heat treatment. In the primary heat treatment process, the temperature is kept at 815 ° C. for 5 hours and then cooled, and the cooling rate is 175 ° C./h. In the secondary heat treatment process, the temperature is kept at 510 ° C. for 3.5 hours and the cooling rate is 110 ° C./h. is there. After cooling to room temperature, the magnetic properties of the sample were measured. For comparison, a magnet was manufactured by adding Dy by a conventional melting method. The magnet characteristics are shown in Table 19-1. The composition components of this magnet were analyzed by ICP analysis and are shown in Table 19-2. Magnets were produced with this composition by conventional methods.

Example 20
The manufacturing method of this example is as follows. The invention produced an R ^a FeMB magnet by the steps of alloy melting, powder control, molding and sintering, and obtained a magnet of 10 × 10 × 10 (10 is c-axis direction, unit mm) by wire cutting. ^Rb was plated on the surface of the magnet according to the present invention. Specific parameters adopted by the electrodeposition method (method for producing a rare earth film using an ionic liquid) are as follows: the ionic liquid is 1-butyl-1-methylpyrrolidinium bis (trifluoromethylsulfonyl) imide, The concentration of GdCl ₃ , which is a salt, is 0.3 mol / L, the electrodeposition temperature is 45 ° C., the current density at a constant potential is 5000 A · m ⁻² , and 8000 seconds after the start of film formation The film formation was stopped, and the film thickness was 15.0 μm. The sample was then subjected to a two-step heat treatment. In the primary heat treatment process, the temperature is kept at 845 ° C. for 3 hours and then cooled, and the cooling rate is 165 ° C./h. In the secondary heat treatment process, the temperature is kept at 530 ° C. for 5.5 hours and the cooling rate is 120 ° C./h. is there. After cooling to room temperature, the magnetic properties of the sample were measured. For comparison, a magnet was manufactured by adding Gd by a conventional melting method. The magnet characteristics are shown in Table 20-1. The composition components of this magnet were analyzed by ICP analysis and are shown in Table 20-2. Magnets were produced with this composition by conventional methods.

Example 21
The manufacturing method of this example is as follows. In the invention, a RaFeMB magnet was manufactured by steps of alloy melting, powder control, molding, and sintering, and a magnet of 10 × 10 × 6 (6 is in the c-axis direction, unit mm) was obtained by wire cutting. ^Rb was plated on the surface of the magnet according to the present invention. Specific parameters adopted by the electrodeposition method (method for producing a rare earth film using an ionic liquid) are as follows: the ionic liquid is 1-butyl-1-methylpyrrolidinium bis (trifluoromethylsulfonyl) imide, The concentration of TbCl ₃ , which is a simple salt, is 0.23 mol / L, the electrodeposition temperature is 65 ° C., the current density at a constant potential is 500 A · m ⁻² , and 3600 seconds after the start of film formation The film formation was stopped, and the film thickness was 1.0 μm. The sample was then subjected to a two-step heat treatment. In the primary heat treatment process, the temperature is kept at 865 ° C. for 4.5 hours and then cooled, and the cooling rate is 195 ° C./h. In the secondary heat treatment process, the temperature is kept at 545 ° C. for 4.5 hours and the cooling rate is 140 ° C./hour. h. After cooling to room temperature, the magnetic properties of the sample were measured. For comparison, a magnet was manufactured by adding Tb by a conventional melting method. The magnet characteristics are shown in Table 21-1. The composition components of this magnet were analyzed by ICP analysis and are shown in Table 21-2. Magnets were produced with this composition by conventional methods.

  The above are only preferred embodiments of the present invention, and the present invention is not limited thereto. Those skilled in the art will appreciate that various changes and modifications can be made to the present invention. Various modifications, substitutions, improvements, and the like are all encompassed by the present invention without departing from the spirit and scope of the present invention.

Claims (8)

1) R ^a FeMB in a general step in which the tempering step is omitted (where R ^a is at least one element selected from Nd, Pr, La, Ce, Sm, Sc, Y and Eu, and its content) Is 23 to 35 wt%, B is elemental boron, its content is 0.8 to 1.2 wt%, M is selected from transition metals other than Fe, and its content is 0 .01-5 wt%, the balance being Fe and inevitable impurities.) Manufacturing the magnet;
2) adding an ionic liquid whose main salt is R ^b Cl ₃ (wherein R ^b is at least one element selected from Tb, Dy, Gd and Ho) to the container;
3) producing an ^Rb film by a constant potential electrodeposition method, obtaining a magnet having an ^Rb film, the anode being pure metal ^Rb , and the cathode being ^a RaFeMB matrix;
4) A step of subjecting the magnet of step 3) to a tempering heat treatment to obtain a high coercive force Nd—Fe—B rare earth permanent magnet;
In the manufacturing process of Nd—Fe—B rare earth permanent magnet containing
Production wherein the ionic liquid of step 2) is selected from 1-ethyl-3-methylimidazolium tetrafluoroborate or 1-butyl-1-methylpyrrolidinium bis (trifluoromethylsulfonyl) imide process.   The manufacturing process according to claim 1, wherein the general steps of step 1) include alloy melting, milling, forming and sintering steps. The manufacturing process according to claim 1, wherein the concentration of R ^b Cl ₃ which is a main salt in step 2) is 0.1 to 0.5 mol / L. The process parameters of the electrodeposition method in step 3) are as follows: current density is 500 to 10000 A · m ⁻² , electrodeposition time is 300 to 10000 s, and electrodeposition temperature is 20 to 70 ° C. The manufacturing process described. The manufacturing process according to claim 1, wherein a thickness of the ^Rb film manufactured in the step 3) is 0.1 to 15 µm.   The manufacturing process according to claim 1, wherein the tempering heat treatment in step 4) includes primary high temperature tempering and secondary low temperature tempering. 7. The manufacturing process according to claim 6 , wherein the temperature of the primary high-temperature tempering heat treatment is 700 to 1000 ° C., the treatment time is 1 to 100 h, and the cooling rate is 50 to 300 ° C./min. The manufacturing process according to claim 6 , wherein the temperature of the secondary low-temperature tempering heat treatment is 400 to 655 ° C, the treatment time is 1 to 10 hours, and the cooling rate is 50 to 200 ° C / min.

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