JP4867762B2 - Rare earth magnet manufacturing method and magnet obtained thereby - Google Patents

Description

  The present invention relates to a method for producing a rare earth magnet and a magnet obtained thereby.

As a technique for achieving high magnetic properties of a rare earth magnet containing a rare earth element, a method of forming a nanocomposite structure in which a magnetic phase having a high saturation magnetic flux density and a magnetic phase having a large magnetic anisotropy are combined is known. In such a nanocomposite magnet, the above two phases cause an exchange interaction, and excellent magnetic properties are obtained by combining the properties of the respective phases. For example, a nanocomposite magnet having an Nd-Fe-B phase and an α-Fe phase is formed by forming an Fe layer on an Nd-Fe-B raw material powder by sputtering, laser deposition, plating, etc. It is shown that it can be obtained by molding (see Non-Patent Document 1 below).
S. Liu et. Al., IEEE TRANSACTIONS ON MAGNETICS, VOL. 42, NO.10, OCTOBER, 2006.

  Among the methods described above, methods such as sputtering and laser vapor deposition tend to increase the manufacturing cost due to the large size of the apparatus. Therefore, in the production of practical magnets, a method using plating is adopted. It is preferable. However, according to the study by the present inventors, when a magnet having a nanocomposite structure is formed by plating a rare earth magnet raw material powder, the magnetic characteristics as expected are often not obtained. found.

  Therefore, the present invention has been made in view of such circumstances, and in a method for producing a rare earth magnet having a nanocomposite structure by plating raw material powder, a rare earth magnet having excellent magnetic properties can be obtained. An object is to provide a manufacturing method. Another object of the present invention is to provide a rare earth magnet obtained by such a manufacturing method.

  In order to achieve the above-mentioned object, the present inventors have conducted intensive research and found that sufficient magnetic properties cannot be obtained in the formation of a nanocomposite magnet by plating such as rare earth elements contained in the raw material powder during plating. It has been found that elution has occurred, and this is due to the corrosion of the raw material powder. Accordingly, the inventors have found that by suppressing the corrosion of the raw material powder during plating, it is possible to satisfactorily form a rare earth magnet capable of obtaining high magnetic properties due to the nanocomposite structure, and the present invention has been completed.

That is, the method for producing a rare earth magnet of the present invention includes an amine compound that forms a complex with a compound of at least one metal atom selected from the group consisting of an iron atom, a nickel atom, a cobalt atom, and a manganese atom, and an ion of the metal atom. And a plating step of plating the rare earth magnet raw material powder with the metal element using a plating solution having a pH of 8 to 12, and forming the raw material powder after the plating step into a nanocomposite structure A rare earth magnet having a forming step.

  In the plating step in the production method of the present invention, first, since the pH of the plating solution is 8 to 12, rare earth elements in the magnetic powder are hardly eluted in the plating solution by forming a nano-level hydroxide film. . In addition, the metal for forming a plating contained in the plating solution can be easily replaced with the rare earth element of the magnetic powder, which may cause corrosion of the magnetic powder. On the other hand, in this invention, substitution of the metal atom with the rare earth element can be suppressed by complexing the metal atom ion in the plating solution by containing the amine compound. As a result, the magnetic powder is hardly corroded in the plating step, and a magnet having a nanocomposite structure having excellent magnetic properties can be obtained. However, the operation according to the present invention is not necessarily limited to this.

  In the production method of the present invention, the plating solution preferably contains at least an iron atom compound. By doing so, the magnetic powder is plated with iron having a relatively high saturation magnetic flux density, and the magnetic properties of the obtained rare earth magnet tend to be obtained particularly well.

The amine compound to be contained in the plating solution, preferably one sequential formation constant K ₁ of the first stage reaction at the time of forming the ion complexes of the metal atoms is in the range of 2.0 to 15.0.

Here, the sequential generation constant K ₁ is a value defined as follows. In the solution, the metal atom ion (metal ion) forms a complex with the amine compound having a complexing action as the ligand L. In this complex, the ligand L binds to the metal ion M stepwise. Formation constants at each stage is defined by K _n, referred to as sequential formation constants it. That is, the following formula:
ML _n-1 + L = ML _n (1)
In respect to the first n-stage reaction represented, the successive formation constant K _n, the following formula:
K _n = [ML _n ] / [ML _n−1 ] [L] (2)
Defined by Therefore, the following formula:
M + L = ML (3)
For the first-stage reaction represented by the following formula, the sequential formation constant K ₁ of the first-stage reaction is
K ₁ = [ML] / [M] [L] (4)
Defined by

In the above formulas (2) and (4), [M], [L], [ML], [ML _n ], etc. are the metal ion M, ligand L, mononuclear complex ML, ML _{n respectively} . Mean concentration.

Thus, the successive formation constant K ₁ of the amine compound in the plating solution is in the range of 2.0 to 15.0, as compared with the case of the range, resulting easily complexation of metal ions Therefore, it is possible to perform plating better while suppressing the corrosion of the magnetic powder.

  Moreover, it is preferable that the plating solution used with the manufacturing method of this invention further contains a reducing agent. When the plating solution contains a reducing agent, it is possible to effectively perform electroless plating, and furthermore, corrosion can be suppressed and magnetic plating can be performed satisfactorily.

  The present invention also provides a rare earth magnet that can be obtained by the manufacturing method described above. Since the rare earth magnet obtained by the production method of the present invention is formed from a magnetic powder that is well plated and has little corrosion, it has a nanocomposite structure that can exhibit excellent magnetic properties. Become.

  ADVANTAGE OF THE INVENTION According to this invention, in the method of manufacturing the rare earth magnet which has a nanocomposite structure by plating raw material powder, it becomes possible to provide the manufacturing method from which the rare earth magnet which has the outstanding magnetic characteristic is obtained.

  Hereinafter, preferred embodiments of the present invention will be described in detail.

  First, a preferred embodiment of a rare earth magnet obtained by the production method of the present invention will be described. FIG. 1 is a schematic diagram showing an enlarged cross-sectional configuration of a rare earth magnet according to a preferred embodiment. As shown in FIG. 1, a rare earth magnet 10 (hereinafter abbreviated as “magnet 10”) has a large number of main phase particles 2 each covered by a coating layer 4 and a binder 6 filling them. ing. As described above, the magnet 10 is configured by binding the magnetic powder (magnetic material) including the main phase particles 2 coated with the coating layer 4 with the binder 6.

  In the magnet 10, the main phase particle 2 includes a rare earth element and is composed of an intermetallic compound having properties as a magnet. Examples of the intermetallic compound include those having a composition containing a rare earth element and a transition element other than the rare earth element. Examples of rare earth elements include Nd, Sm, and the like, and Pr, Er, Tm, and the like may further be included. Examples of the transition element include Fe, Co, and Ni. Specific examples of such intermetallic compounds include Nd—Fe—B compounds and Sm—Co compounds.

Among them, as the intermetallic compound constituting the main phase particles 2, preferably it has a crystal structure of the ₅ type CaCu. The main phase particles 2 composed of such an intermetallic compound have a large anisotropic magnetic field. This is because the CaCu ₅ type crystal structure has an anisotropic structure in which rare-earth elements are densely layered and layered in layers, and the rare-earth elements are connected in the hexagonal c-axis direction. Therefore, it is considered that this is because a large anisotropy is expressed.

Specifically, as the Sm—Co based intermetallic compound, SmCo ₅ is preferable. Intermetallic compounds having a composition of SmCo ₅ tend to have a large anisotropic magnetic field. Furthermore, as the Sm—Co-based intermetallic compound, a Sm—Co—B-based compound in which a part of Co is substituted with boron (B) is more preferable. By substituting part of Co with B in this way, since B has a smaller atomic radius than Co, the distance between Sm in the c-axis direction can be reduced in the CaCu ₅ type structure. It is thought that a direction can be obtained. The intermetallic compound SmCo-B-based, for _{example, SmCo 4 B, SmCo 3 B} 2, Sm 2 Co 7 B 3 _{and, Sm,} such as _{Sm 3 Co 11 B 4 N Co} 3N + 2 B 2N-2 (N Are those having a composition represented by 2 or more).

  Furthermore, the intermetallic compound is more preferably an Sm—Co—Fe—B based compound in which a part of Co is substituted with Fe in the Sm—Co—B based intermetallic compound. Thus, by replacing part of Co with Fe, the Curie temperature can be sufficiently increased while increasing the anisotropic magnetic field of the intermetallic compound. By having the main phase particles 2 made of an intermetallic compound having a high Curie temperature, the magnet 10 can maintain excellent magnetic properties even at high temperatures. From the viewpoint of obtaining a sufficient anisotropic magnetic field and increasing the Curie temperature, the Fe substitution amount of Co is preferably 75% or less, more preferably 25 to 75%, based on the number of atoms.

  The shape of the main phase particle 2 is not particularly limited, but may have a plate shape, a needle shape, or the like. In particular, when the main phase particle 2 has a needle-like shape, it can have a large anisotropic energy in the axial direction due to the shape. As a result, in the magnet 10, excellent magnetic anisotropy can be obtained by the main phase particles 2. Here, the needle-like shape refers to a shape in which the length of the major axis is three times or more with respect to the minor axis.

  The coating layer 4 is a plating layer formed by plating containing a metal element of Fe, Ni, Co, or Mn. This coating layer 4 may be comprised only from one type of these metal elements, may be comprised from multiple types, and may be comprised by the alloy of these metal elements. Moreover, the coating layer 4 may further contain other metal elements and the like as long as the metal element contains the metal element as a main component.

  The covering layer 4 is particularly preferably a layer containing Fe having a relatively high saturation magnetic flux density as a main component. In this case, the coating layer 4 may be comprised only from Fe, and may contain it combining metal elements other than Fe. Examples of elements other than Fe contained in the coating layer 4 include cobalt (Co) and nitrogen (N), and it is more preferable to have a composition containing 20 to 50 atomic% of Co. By containing Co in addition to Fe, the saturation magnetic flux density of the coating layer 4 tends to be improved.

  In the magnet 10, the average particle diameter of the main phase particles 2 is preferably 0.1 to 100 μm, and more preferably 0.2 to 20 μm. Moreover, the coating layer 4 has coat | covered the main phase particle | grains 2 uniformly, and the thickness is preferable in it being 0.01-10 micrometers, and it is more preferable in it being 0.02-3 micrometers. When the main phase particles 2 and the coating layer 4 satisfy such conditions, exchange interaction is likely to occur between these phases, and sufficient magnetic anisotropy and saturation magnetic flux density due to these two phases can be obtained. And excellent magnetic properties can be obtained.

  The binder 6 in the magnet 10 is a component that binds the particles constituting the magnetic powder. The binder 6 is made of a material having a saturation magnetic flux density lower than that of the material constituting at least the main phase particle 2 and the coating layer 4, and more preferably made of a nonmagnetic (paramagnetic, diamagnetic) or antiferromagnetic material. . Specific examples of the binder 6 include rare earth metals (Sm or La), simple metals such as Mn, Zn, and Cu, alloys such as NiO, FeMn, and FeAl, or resins.

  Among these, Sm can suppress a decrease in anisotropy due to disorder of the structure of the magnetic powder, etc. Zn is suitable for dispersing the magnetic powder because of its low melting point, and Cu is malleable. -It has excellent ductility, is suitable for the binder 6, and has the advantage that it can be easily formed by plating. Furthermore, NiO and FeMn are inexpensive and can be easily used as the binder 6, and the resin has advantages such as easy melting and easy dispersion of the magnetic powder. As the binder 6, it is preferable to select and use the above-mentioned components appropriately in accordance with desired characteristics.

  Next, a preferred embodiment of the method for producing a rare earth magnet of the present invention will be described by taking the method for producing the magnet 10 having the above-described configuration as an example.

  In the manufacture of the magnet 10, first, a magnetic powder composed of the main phase particles 2 containing a rare earth element is prepared. The main phase particles 2 can be produced, for example, by a method using a solvent described below, a rapid quenching method, a method using an arc plasma gun, or the like.

  In the method using a solution, for example, main phase particles 2 are obtained as follows. That is, first, the compound of each element contained in the above-mentioned intermetallic compound is dissolved in a solvent such as glycols. Here, as a combination of the raw material compounds, for example, a samarium salt, a cobalt salt, a boron salt, and the like having a mass ratio capable of obtaining a desired composition can be given. Next, the obtained solution is sufficiently stirred, and the main phase particles 2 are obtained by reacting the solution while maintaining it at about 150 to 320 ° C.

  In the rapid quenching method, for example, the main phase particles 2 are obtained as follows. That is, first, after a raw material of a compound containing an element contained in the above-described intermetallic compound is dissolved by high frequency or the like, the obtained melt is subjected to a peripheral speed of 15 to 60 m / s of a cooling roll under reduced pressure of Ar gas Quench in the range to obtain flakes. And the main phase particle | grains 2 can be obtained by grind | pulverizing the obtained flakes.

  In the manufacture of the magnet 10, next, the magnetic powder obtained as described above is plated to form a coating layer 4 made of plating on the surface of each main phase particle 2 constituting the magnetic powder ( Plating process). In the present embodiment, the plating includes a plating solution containing at least one metal atom compound selected from the group consisting of Fe, Ni, Co, and Mn, and an amine compound that can form a complex with ions of the metal atom. To form a plating layer containing the metal atoms.

  Here, the plating solution used in the plating step will be described more specifically. First, examples of the compound of each metal atom contained in the plating solution include salts of metal elements, and examples thereof include the following compounds. Examples of the Ni salt compound include nickel sulfate, nickel chloride, nickel bromide, nickel nitrate, nickel sulfamate, nickel hydroxide, nickel carbonate, nickel pyrophosphate and the like. Examples of the Fe salt compound include iron sulfate, iron chloride, iron bromide, iron nitrate, iron sulfamate, iron hydroxide, iron carbonate, and iron pyrophosphate. Furthermore, examples of the Co salt compound include cobalt sulfate, cobalt chloride, cobalt bromide, cobalt nitrate, cobalt sulfamate, cobalt hydroxide, cobalt carbonate, and cobalt pyrophosphate. For example, when the coating layer 4 containing Fe is formed by plating as described above, at least the Fe salt compound may be contained in the plating solution. When the coating layer 4 containing Fe and Co is formed, the plating solution What is necessary is just to contain both Fe salt compound and Co salt compound in it.

On the other hand, the amine compound is not particularly limited as long as it can form a complex as a ligand of the above metal atom ion (metal ion), but the sequential generation of the first stage reaction when forming a complex with the metal ion. is preferably one constant _{K 1} is in the range of 2.0 to 15.0, it is more preferable and 3.0 to 10.0. By using one made with these K ₁ as the amine compound, suppress corrosion by dissolution or the like of rare earth elements in the magnetic powder, it is possible to perform a good plating.

  Examples of such amine compounds include glutamic acid, aspartic acid, ricinic acid, lysine-glutamic acid, lysine-aspartic acid, arginine-glutamic acid, picolinic acid, diaminopropionic acid, diaminobutyric acid, iminodiacetic acid, glycine, alanine, phenylalanine, Methionine, arginine, valine, theanine, glycylglycine, ethylenediamine, diethylenetriamine, triethanolamine, imidazole, 1,10 phenanthroline, phenanthroline ammonia, phthalocyanine, ammonia, ammonium salt, triethylenetetraamine, ethylenediaminetetraacetic acid (EDTA), These mixtures are mentioned.

Among them, glycine, aspartic acid, glutamic acid, ethylenediamine, picolinic acid, glycylglycine, triethylenetetramine, ammonia, or EDTA is preferable as the amine compound because corrosion of the magnetic powder can be particularly favorably suppressed. K _{1 in} forming a complex with each metal atom ion of these amine compounds is, for example, as shown in Table 1 below. Amine compound preferably K ₁ of a metal atom to form a plating is suitably selected so that favorable.

  The pH of the plating solution is 8 to 12, and preferably 9 to 11. When the pH of the plating solution is low, rare earth atoms contained in the magnetic powder tend to be easily eluted during plating. On the other hand, if the pH is too high, iron and the like contained in the magnetic powder are likely to elute, and this also causes corrosion of the magnetic powder.

  The pH of the plating solution can be adjusted using, for example, a hydroxide salt. Although hydroxide salt is not specifically limited, For example, potassium hydroxide, sodium hydroxide, calcium hydroxide etc. are mentioned. The plating solution may contain boric acid as a pH buffer in addition to the hydroxide salt.

  The content of the metal atom compound contained in the plating solution is preferably 0.1 to 2.0 mol / L, more preferably 0.3 to 1.0 mol / L in terms of metal ion. If the metal atom content is too small, the formation of plating tends to be difficult. On the other hand, if the content of the metal atom compound is too large, other components such as amine compounds are saturated and precipitated, and plating may not proceed well.

  Moreover, it is preferable that the suitable content of an amine compound is as follows in relation to content of a metal ion. That is, the molar ratio of the amine compound to the metal ion is preferably 0.5 to 3.0 times, more preferably 1.2 to 3.0 times the coordination number of the amine compound to the metal ion. 1.3 to 2.0 times more preferable. In this case, corrosion of the magnetic powder is more effectively suppressed, and the solubility of the amine compound in the solvent is improved, so that plating is more reliably formed.

  The plating solution preferably further contains a reducing agent in addition to the metal atom compound and the amine compound. In this case, a redox power is imparted to the plating solution, and electroless plating can be effectively performed. Here, the reducing agent is not particularly limited as long as it can chemically reduce metal ions contained in the plating solution. Examples of the reducing agent include hypophosphorous acid, hypophosphite compound, tetrahydroboric acid, tetrahydroborate compound, dimethylamine borane, diethylamine borane, hydrazine, titanium (+2) ion, and the like.

  The content of the reducing agent in the plating solution is preferably 0.05 to 0.5 mol / L, more preferably 0.1 to 0.3 mol / L. In this case, the plating on the magnetic powder can be performed more efficiently, and self-decomposition of the plating solution can be made difficult to occur. When the plating solution contains a reducing agent, it may further contain a stabilizer in the range of about 0.01 to 10 mg / L. Such stabilizers include thiourea, bismuth (Bi), lead (Pb) and the like.

  Moreover, when the plating solution contains an Fe compound, it is desirable that Fe ions exist in a divalent state, but the divalent Fe ions are easily oxidized to trivalent by dissolved oxygen or the like. Furthermore, oxidation may also occur in a complex of Fe and an amine compound. Therefore, in order to prevent these, an antioxidant such as ascorbic acid can be appropriately added to the plating solution.

  In the plating step, the magnetic powder composed of the main phase particles 2 is plated using the above plating solution. As a plating method in this case, either electrolytic plating or electroless plating can be applied. When performing electroplating, plating can be performed using a balanced rotating barrel. On the other hand, when performing electroless plating, a coating layer 4 made of plating is formed on the surface of each main phase particle 2 by immersing the magnetic powder in a plating solution further containing a reducing agent as described above. Can do.

  In the manufacture of the magnet 10, subsequently, the magnetic powder composed of particles in which the coating layer 4 is formed on the surface of each main phase particle 2 by the above-described plating process is bulked by bonding with the binder 6. This bulking can be performed by, for example, a method of molding the magnetic powder after it is covered with the binder 6 or a method of molding the magnetic powder in a state where the magnetic powder is dispersed in the binder 6.

  For example, when using Zn as the binder 6, first, a container containing Zn is heated to about 500 ° C. to melt Zn, and then the above magnetic powder is added and dispersed therein. Next, the temperature of the mixture is gradually raised, and Zn is evaporated while molding in a magnetic field, whereby the bulk magnet 10 is obtained. In order to obtain a desired product shape, the magnet 10 once obtained may be roughly pulverized and then further molded in a magnetic field.

  Moreover, when using resin, such as PPS (polyphenylene sulfide) resin, as the binder 6, for example, the above-mentioned magnetic powder and resin are mixed, and the magnet 10 (bond magnet) is obtained by extruding the resulting mixture. Is obtained.

  In addition, as a magnet of this invention, the thing which does not have the binder 6 like the magnet 10 mentioned above is mentioned. A magnet not having the binder 6 can be obtained, for example, as follows. That is, first, the above magnetic powder is hot-pressed and molded. The obtained molded body is made anisotropic by hot plastic working. Next, the anisotropically processed product is once pulverized to obtain pulverized powder. This pulverized powder is put into a mold and molded in a magnetic field. And the magnet which does not have the binder 6 is obtained by sintering the obtained molded object.

  Here, FIG. 2 is a diagram schematically showing a cross-sectional configuration of the rare earth magnet of another embodiment, and shows a magnet formed without using the binder 6. As shown in FIG. 2, the magnet 20 obtained without using the binder 6 has a large number of particles composed of a large number of main phase particles 2 and a coating layer 4 covering the surface, and the adjacent coating layer 4. It has a configuration in which they are almost integrated. In other words, the grain boundary portion of a large number of main phase particles 2 has a configuration filled with the coating layer 4.

  As described above, according to the manufacturing method of the preferred embodiment described above, the plating step includes the compound of the specific metal atom and the amine compound capable of complexing with the ion of the metal atom, and has a pH of 8 to 12. Since the plating solution is used, corrosion of the magnetic powder due to elution of rare earth atoms during plating is greatly reduced. As a result, a rare earth magnet having excellent magnetic anisotropy inherent to magnetic powder containing rare earth elements can be obtained.

  The rare earth magnet (magnet 10) thus obtained has a composite structure of the main phase particles 2 made of an intermetallic compound containing a rare earth element and the coating layer 4 made of the above metal atom plating. A nanocomposite structure in which exchange interaction occurs between the two is formed. Therefore, the magnet 10 has excellent magnetic properties in which a high coercive force due to the magnetic anisotropy of the main phase particles 2 and a high magnetic flux with the coating layer 4 made of metal are sufficiently exhibited.

[Production of rare earth magnets: Examples 1 to 16, Comparative Examples 1 to 8]

(Production of magnetic powder (main phase particle 2))
The raw material of the SmCo ₄ B composition was melted at high frequency in the nozzle of a high-speed quenching device. The obtained melt was rotated by attaching a copper cooling roll installed immediately below the nozzle to a peripheral speed of 25 m / s, and this melt was ejected from a φ0.9 mm nozzle tip hole. The lysate was quenched with a roll and then blown away by centrifugal force to form a thin piece having a thickness of 50 μm. This was pulverized by a ball mill to obtain a magnetic powder (corresponding to main phase particle 2) made of 5 μm of SmCo ₄ B. The average particle size of the magnetic powder was measured using a laser diffraction type particle size distribution measuring device master sizer 2000 according to the Fraunhofer diffraction theory using laser light. However, in the case of needles, the sphere equivalent diameter was estimated from the lengths of the major axis and minor axis measured by TEM or SEM observation, and the average value was taken as the average particle diameter.

(Formation of coating layer (plating))
The magnetic powder obtained above is put into a parallel barrel, immersed in a citric acid solution adjusted to pH 8 for 10 seconds, washed with water, and then immediately plated with a plating solution for about 30 minutes. did. In Examples 1 to 16 and Comparative Examples 1 to 8, plating was performed by changing the plating solution and the plating conditions as shown in Tables 2 to 5. As a result, a coating layer having a thickness of about 1 μm was formed for both electrolysis and electroless. Tables 2 to 5 also show the composition of the coating layer (plating) formed by the plating process.

(Formation of rare earth magnets)
Each magnetic powder after the above plating step was washed with water and vacuum-dried, and then subjected to hot plastic working by applying a pressure of 40 ton / cm ² at 800 ° C. An example rare earth magnet was obtained.
[Characteristic evaluation]

  Each rare earth magnet obtained in Examples 1 to 16 and Comparative Example 8 was measured using a BH tracer, and the residual magnetic flux density (Br) and the holding force (HcJ) by each magnet were calculated. The obtained results are collectively shown in Tables 2 to 5.

  From the results of Tables 2 to 5, in Examples 1 to 16 in which plating was performed on the magnetic powder using a specific amine compound and a plating solution having a pH of 8 to 12, the amine compound was not contained or the amine It was confirmed that a rare earth magnet having excellent magnetic properties was obtained as compared with Comparative Examples 1 to 8 in which the pH was outside the range of the present invention even when the compound was included.

It is a schematic diagram which expands and shows the cross-sectional structure of the magnet which concerns on suitable embodiment. It is a figure which shows typically the cross-sectional structure of the rare earth magnet of other embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Magnet, 2 ... Main phase particle, 4 ... Coating layer, 6 ... Binder.

Claims (7)

A compound of at least one metal atom selected from the group consisting of an iron atom, a nickel atom, a cobalt atom and a manganese atom, and an amine compound which forms a complex with an ion of the metal atom, and has a pH of 8 to A plating step of applying a plating containing the metal element to a magnetic powder containing a rare earth element using a plating solution of 12.
A molding step for obtaining a rare earth magnet having a nanocomposite structure by molding the magnetic powder after the plating step;
A method for producing a rare earth magnet, comprising:   The method for producing a rare earth magnet according to claim 1, wherein the plating solution contains at least a compound of iron atoms. In the plating solution,
The content of the metal atom compound is 0.1 to 2.0 mol / L in terms of ions of the metal atom,
The amine compound, sequential formation constant K ₁ of the first stage reaction at the time of forming the ion complexes of the metal atoms is made of a 2.0 to 15.0, and,
3. The rare earth according to claim 1 , wherein the molar ratio of the amine compound to the ions of the metal atom is 0.5 to 3.0 times the coordination number of the amine compound to the metal ion. Magnet manufacturing method.   The said plating solution further contains a reducing agent, The manufacturing method of the rare earth magnet as described in any one of Claims 1-3 characterized by the above-mentioned. 5. The method for producing a rare earth magnet according to claim 1, wherein in the forming step, the magnetic powder is bonded by a binder to be formed. The method for producing a rare earth magnet according to claim 5, wherein the binder is made of a nonmagnetic or antiferromagnetic material. Rare earth magnets which can be obtained by the method according to any one of claims 1-6.

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