KR102399418B1 - Manufacturing method of sintered magnetic and sintered magnetic manufactured by the same - Google Patents

Abstract

The method for manufacturing a sintered magnet according to an embodiment of the present invention is [(La, Ce) _1-x Nd _x ] ₂ Fe _y B (x=0~0.5, y=12~13) powder particles to prepare powder particles mixing the raw materials, reacting the mixed powder particle raw material using a Ca reduction-diffusion method, and washing, pulverizing and drying the material formed by the reaction to prepare a magnet powder.

Description

A method for manufacturing a sintered magnet and a sintered magnet manufactured thereby

The present invention relates to a method for manufacturing a sintered magnet and a sintered magnet manufactured thereby.

The NdFeB-based magnet is a permanent magnet having a composition of Nd ₂ Fe ₁₄ B, which is a compound of Nd, iron, and boron (B), a rare earth element, and has been used as a general-purpose permanent magnet for 30 years after being developed in 1983. These NdFeB-based magnets are used in various fields such as electronic information, automobile industry, medical equipment, energy, and transportation. In particular, it is used in products such as machine tools, electronic information devices, home appliances, mobile phones, robot motors, wind power generators, small motors for automobiles, and drive motors in line with the recent trend of light weight and miniaturization.

Because NdFeB-based magnets are expensive rare earth elements, they replace Nd, Dy, Tb, and Pr with metals such as La and Ce, which have abundant reserves on earth and are inexpensive, so their performance is better than that of ferrite magnets and their performance is better than that of NdFeB-based magnets. It is being studied whether it can be kept low or similar. In the document of U.S. Publication No. US2016-0141083, [La, Ce] _1-x Nd _x which is an isotropic nanocrystalline grain obtained by induction melting and strip casting process of a high-purity raw material in an inert gas atmosphere ] ₂ Fe ₁₄ B ribbons are prepared by hot-pressing and die-upset processes to manufacture sintered magnets, wrap these sintered magnets with Nd ₇₀ Cu ₃₀ alloy ribbons, and then at 700 degrees Celsius By heat-treating for 6 hours, it is possible to manufacture a core-shell type Nd-reduced sintered magnet in which the Nd content increases from the center to the surface of the grains. However, in this case, only sub-micron-sized [La, Ce] _1-x Nd _x ] ₂ Fe ₁₄ B grains can form a gradient in Nd content by effective diffusion of the Nd-Cu alloy.

According to the content published in Scientific Reports volumn 6, 32200 (2016), the Nd-reduced sintered magnet manufactured by mixing (La, Ce) rich NdFeB powder and (La, Ce) free NdFeB powder is, (La, Ce) Each of the rich Nd-based powder and (La, Ce)-free Nd-based powder is prepared by induction melting, strip casting, hydrogen decrepitation, and jet milling processes, and the two types of powder are mixed in an appropriate weight ratio. And it is possible to manufacture a sintered magnet in which the content of La-Ce is controlled by using a powder metallurgy method. However, the hydrogen fracturing and jet mill processes require expensive special equipment, and there is a problem in that it is difficult to reduce the process cost because the material loss rate is 30 to 40%. In addition, when two types of mixed powders are mixed and sintered, holes may be formed due to the difference in solid diffusion between Nd and (La, Ce) (Acta Materiala 2018, 145, 18-28).

Embodiments are to provide a rare-earth magnet that has better performance than a ferrite magnet while reducing the amount of Nd and the like, and has lower performance than an NdFeB-based magnet or can be maintained similarly, and a method for manufacturing the same.

However, the problems to be solved by the embodiments of the present invention are not limited to the above problems and may be variously expanded within the scope of the technical idea included in the present invention.

The method for manufacturing a sintered magnet according to an embodiment of the present invention is [(La, Ce) _1-x Nd _x ] ₂ Fe _y B (x=0~0.5, y=12~13) powder particles to prepare powder particles mixing the raw materials, reacting the mixed powder particle raw material using a Ca reduction-diffusion method, and washing, pulverizing and drying the material formed by the reaction to prepare a magnet powder.

The step of mixing the powder particle raw material is a step of mixing La ₂ O ₃ powder CeO ₂ powder and Nd ₂ O ₃ powder with a wet ball mill or a dry ball mill, and then mixing B, Cu/Al/Ga fluoride and Fe. may include

The reacting the powder particle raw material may include mixing Ca after the mixing of the powder particle raw material.

10 to 30 wt% of wet-pulverized NdH ₂ powder may be added to the prepared magnet powder.

The wet-pulverized NdH ₂ powder may be heat-treated at 1000 to 1100 degrees Celsius.

In the heat-treated magnet powder, a nano-thick (Nd, La, Ce) ₂ Fe ₁₄ B shell may be formed on the grain surface due to a difference in solid diffusion between Nd and La/Ce.

The content of Nd contained in the shell of the nano-thick (Nd, La, Ce) ₂ Fe ₁₄ B may be greater than the content of Nd contained in the core of (Nd, La, Ce) ₂ Fe ₁₄ B formed in the center of the grains. there is.

In the heat-treated magnet powder, a nano-thick (Nd, La, Ce) ₂ Fe ₁₄ B shell is formed on the grain surface due to the difference in solid diffusion between Nd and La/Ce, and the nano-thick (Nd, La, Ce) ) The thickness of the shell of ₂ Fe ₁₄ B may be thinner than the thickness of the core of (Nd, La, Ce) ₂ Fe ₁₄ B formed in the center of the grains.

The NdH ₂ powder may be wet pulverized in a hexane atmosphere.

The method for manufacturing a sintered magnet may further include a step of heat-treating in a vacuum sintering furnace after preparing a compact by mixing the manufactured magnet powder with NdH ₂ powder, cooling it to room temperature in an argon atmosphere, and then performing a post-heat treatment. there is.

A sintered magnet according to another embodiment of the present invention is obtained by mixing La ₂ O ₃ powder CeO ₂ powder and Nd ₂ O ₃ powder by a wet ball mill or a dry ball mill, and then mixing B, Cu/Al/Ga fluoride and Fe reacting the mixed powder particle raw material using a Ca reduction-diffusion method, washing, pulverizing and drying the material formed by the reaction to prepare a magnet powder, and to the manufactured magnet powder, It is produced by a sintered magnet manufacturing method comprising the step of adding 10 to 30% by weight of wet-pulverized NdH ₂ powder.

According to embodiments, it is possible to synthesize the Nd-reduced magnet powder with a relatively low reaction temperature and a short reaction time by using a Ca reduction-diffusion method after mixing the raw materials for forming the sintered magnet.

In addition, in the process of mixing and sintering the crystalline [La, Ce] _1-x Nd _x ] ₂ Fe ₁₄ B particles and wet-milled NdH ₂ particles prepared by chemical synthesis (oxidation-reduction), Nd and La/Ce Nd-rich (Nd, La, Ce) ₂ Fe ₁₄ B shell may be formed on the grain surface due to the difference in solid diffusion of

1 is an SEM photograph of a magnet powder prepared according to Example 1.
2 is a graph showing an XRD pattern of the magnet powder prepared according to Example 1 of the present invention.
3 is a graph showing the MH data of the magnet powder prepared according to Example 1.
4 is a graph illustrating an XRD pattern after sintering the magnet powder prepared according to Example 1. Referring to FIG.
5 is a graph showing the magnetic flux density and coercive force of the sintered magnet manufactured according to Example 1. Referring to FIG.
6 is a graph showing an XRD pattern of the magnet powder prepared according to Example 2. Referring to FIG.
7 is a graph showing the MH data of the magnet powder prepared according to Example 2.
8 is a graph showing an XRD pattern after sintering the magnet powder prepared according to Example 2. Referring to FIG.
9 is a graph showing the magnetic flux density and coercive force of the sintered magnet manufactured according to Example 2;

Hereinafter, with reference to the accompanying drawings, various embodiments of the present invention will be described in detail so that those of ordinary skill in the art can easily carry out the present invention. The present invention may be embodied in several different forms and is not limited to the embodiments described herein.

In addition, throughout the specification, when a part "includes" a certain component, this means that other components may be further included, rather than excluding other components, unless otherwise stated.

For the general manufacture of NdFeB-based magnets, a strip/mold casting or melt spinning method based on metal powder metallurgy is known. First, in the case of the strip/mold casting method, it is a process of manufacturing an ingot by melting metals such as Nd, iron, and boron (B) through heating, coarsely pulverizing crystal grains, and manufacturing micro particles through a refinement process. . By repeating this, a powder is obtained, and an anisotropic sintered magnet is manufactured by pressing and sintering under a magnetic field.

In addition, the melt spinning method melts metal elements, pours them into a wheel rotating at a high speed, cools them, and after jet milling and pulverization, blends them with a polymer to form a bonded magnet, or presses to make a magnet.

However, all of these methods have problems in that a grinding process is essential, the grinding process takes a long time, and a process of coating the surface of the powder after grinding is required.

In the method for manufacturing a sintered magnet according to an embodiment of the present invention, La ₂ O ₃ , CeO ₂ , Nd ₂ O ₃ powder is uniformly mixed with a wet ball mill, and then B, Cu/Al/Ga fluoride, Fe, and Ca are turbular. After sequentially mixing the above raw materials using a mixer, Ca reduction-diffusion can be used to synthesize Nd-reduced magnet powder with a relatively low reaction temperature of about 950 degrees Celsius and a short reaction time of about 10 minutes.

In addition, micrometer-sized [(La,Ce) _1-x Nd _x ] ₂ Fe _y B particles (x=0~0.5, y=12~13) prepared by oxidation-reduction chemical synthesis and wet pulverized micro Nano-thick Nd-rich (Nd,La,Ce) ₂ Fe ₁₄ B on the grain surface due to the difference in solid diffusion between Nd and La/Ce in the process of properly mixing and sintering metric-sized NdH ₂ particles A shell may be formed. The micrometer size described herein means a size of about 1 micrometer or more and 5 micrometers or less.

Specifically, the micrometer-sized [(La,Ce) _1-x Nd _x ] ₂ Fe _y B particles (x=0~0.5, y=12~13) prepared by oxidation-reduction chemical synthesis were wet-milled NdH ₂ It may be heat-treated at 1000 to 1100 degrees Celsius by adding 10 to 30% by weight of the powder particles. Preferably, 10 to 15% by weight of the NdH ₂ powder particles may be added. Here, the reason for adding the NdH ₂ powder particles is to induce liquid phase sintering during the sintering process to obtain a sintered magnet having a high density.

J. Mater. Sci. tech. According to the 2017, 33, 1087-1096 paper, unlike the Nd-Fe-B ternary phase diagram, CeFe ₂ also exists in the Ce-Fe-B ternary phase diagram. The properties of the sintered magnet may be deteriorated. On the other hand, since CeFe ₂ is not observed in the magnet powder manufactured by the synthesis method of this example, there is no decrease in coercive force in the magnetization hysteresis curve of the magnet powder, and there is no decrease in the sintered density in the manufacture of the sintered magnet. Compared to the conventional metal metallurgy, which is melted at a high temperature of around 1500 degrees Celsius and then undergoes a strip casting process, in this embodiment, the Ca reduction-diffusion method is used to synthesize it at a relatively low temperature for a short time, so that impurities are removed from the magnet powder. hard to precipitate

According to this embodiment, [(La,Ce) _1-x Nd _x ] _y Fe ₁₄ B particles (x = 0 ~ 0.5, y = 12 ~ 13) and wet The pulverized NdH ₂ particles are properly mixed to form a compact, and then magnets are manufactured through sintering and post-heat treatment processes. At this time, a nano-thick Nd-rich (Nd,La,Ce) ₂ Fe ₁₄ B shell may be formed on the grain surface of the sintered magnet due to the difference in the degree of solid diffusion between Nd and La/Ce. A (Nd,La,Ce) ₂ Fe ₁₄ B core having a relatively low Nd content may be formed inside the grains, and the Nd content included in the shell is smaller than the Nd content included in the core. In addition, in the heat-treated magnet powder, a nano-thick (Nd, La, Ce) ₂ Fe ₁₄ B shell is formed on the crystal grain surface due to the difference in solid diffusion between Nd and La/Ce, and the nano-thick (Nd, La, The thickness of the shell of Ce) ₂ Fe ₁₄ B may be thinner than the thickness of the core of (Nd, La, Ce) ₂ Fe ₁₄ B formed at the center of the grains.

Hereinafter, a method for manufacturing a sintered magnet according to an embodiment of the present invention will be described in more detail. However, the following examples correspond to examples for describing the present invention, and are not limited to these examples.

Example 1

1) (Nd _0.5 La _0.125 Ce _0.375 ) ₂ Fe ₁₂ B (CuAlGa) _0.05 Manufacturing (magnet powder)

La ₂ O ₃ 2.09 g, CeO ₂ 5.4 g, Nd ₂ O ₃ 8.65 g were mixed by a ball mill treatment in an ethanol atmosphere for 3 hours, dried in an air atmosphere, and then dried in a vacuum atmosphere at 900 degrees Celsius After heat treatment for 1 hour at [or La ₂ O ₃ 2.09 g, CeO ₂ 5.4 g, Nd ₂ O ₃ 8.65 g and zirconia balls in a sharpener, mix with a paint shaker for 30 minutes, and add 2 hours with a tubular mixer After mixing], this mixed powder is put in a Nalgen container with B 0.56g, AlF ₃ 0.22g, CuF ₂ 0.26g, GaF ₃ 0.33g, mixed with a paint shaker for 30 minutes, and then Fe Add 34.43 g and mix with a paint shaker for 30 minutes. Finally, add 9.80 g of Ca and mix for 1 hour with a tubular mixer. React in a tube furnace for 10 minutes at 950 degrees Celsius. Put the powder in ethanol in which ammonium nitrate is dissolved and wash it for 10-30 minutes using a homogenizer. 1/10) compared to the amount used for initial cleaning, grind the magnetic powder with a turbular mixer for 2 hours, wash with acetone, and dry.

2) Manufacturing of sintered magnets

Add 10wt% of (Nd _0.5 La _0.125 Ce _0.375 ) ₂ Fe ₁₂ B(Cu AlGa) _0.05 magnetic powder to NdH ₂ pulverized in hexane by using a Spex mill, mix well, put it in a graphite mold, close it with a graphite lid, and then lower the crucible While applying appropriate vibration, compact the mixed powder, put it in a magnetizer, apply a magnetic field at 1.75 kV, heat it in a vacuum sintering furnace at 1040 degrees Celsius for 2 hours, cool the sintered body to room temperature in an Ar atmosphere, and then cool the sintered body to room temperature at 500 degrees Celsius. Post-heat treatment for a period of time. (Nd _0.5 La _0.125 Ce _0.375 ) ₂ Fe ₁₂ B (CuAlGa) 0.05 Add NdH ₂ pulverized in a hexane atmosphere with a weight ratio of 10 wt % to 8 g of _0.05 magnet powder, add butanol as a lubricant to form a magnetic field, and then perform magnetic field molding in a vacuum sintering furnace at After sintering at a temperature of 1030°C for 2 hours, it was magnetized and BH was measured.

Example 2

1) (La _0.25 Ce _0.75 ) ₂ Fe ₁₃ B (CuAlGa) _0.075 Manufacturing (magnet powder)

La ₂ O ₃ 3.96 g, CeO ₂ 10.22 g are mixed in an ethanol atmosphere for 3 hours by a ball mill treatment, the powder is dried in an air atmosphere, and then heat treated in a vacuum atmosphere at a temperature of 900 degrees Celsius for 1 hour [or La ₂ O ₃ 3.96 g, CeO ₂ 10.22 g and zirconia balls are put in a sharpener and mixed with a paint shaker for 30 minutes, and further mixed with a tubular mixer for 2 hours] B 0.53 g, AlF ₃ Put 0.31 g, CuF ₂ 0.37 g, GaF ₃ 0.46 in a nalgentong and mix with a paint shaker for 30 minutes, then add 35.30 g of Fe and mix with a paint shaker for 30 minutes. Finally, add 10.23 g of Ca and use a tubular mixer. After mixing for 1 hour, it is compacted in a quartz tube surrounded by a carbon sheet, and reacted in an inert gas (Ar, He) atmosphere at 950 degrees Celsius for 10 minutes in a tube electric furnace.

Washing, pulverizing, and drying processes of the synthesized powder are the same as in Example 1.

2) Manufacturing of sintered magnets

(La _0.25 Ce _0.75 ) ₂ Fe ₁₃ B (CuAl Ga) 10, 15, 25, and 30 wt% of NdH ₂ pulverized in a hexane atmosphere using a Spex mill, respectively, compared to _0.075 powder, mixed well, and put into a graphite mold After closing with a graphite lid, apply appropriate vibration to the lower part of the crucible, mince the mixed powder, put it in a magnetizer, apply a magnetic field at 1.75 kV, heat it in a vacuum sintering furnace at 1040 degrees Celsius for 2 hours, and then heat the sintered compact in an argon (Ar) atmosphere. After cooling to room temperature, post-heat treatment is performed at 500 degrees Celsius for 1 hour.

In Example 2, only the precursors of La and Ce were put in the mother powder to synthesize the magnet powder, and then NdH ₂ as a sintering aid added during the manufacture of the sintered magnet is used to supply Nd to the magnet powder.

Hereinafter, experimental examples such as SEM photographs and XED patterns of the magnet powder and the sintered magnet prepared according to Examples 1 and 2 will be described.

1 is an SEM photograph of a magnet powder prepared according to Example 1.

Referring to FIG. 1 , it can be seen that the synthesized magnet powder has a size of 1 to 5 micrometers.

2 is a graph showing an XRD pattern of the magnet powder prepared according to Example 1 of the present invention.

Referring to FIG. 2 , the crystallinity of the magnet powder prepared according to Example 1 can be confirmed.

3 is a graph showing M-H data of the magnet powder according to Example 1. FIG.

Referring to FIG. 3 , in the case of the sintered magnet manufactured according to Example 1, a hysteresis curve of the NdFeB sintered magnet powder can be confirmed.

4 is a graph illustrating an XRD pattern after sintering the magnet powder prepared according to Example 1. Referring to FIG.

Referring to FIG. 4 , the degree of orientation in the (105) and (006) directions in the sintered magnet manufactured according to Example 1 can be confirmed.

5 is a graph showing the magnetic flux density and coercive force of the sintered magnet manufactured according to Example 1. Referring to FIG. Specifically, FIG. 5 shows the magnetic flux density (Y-axis) according to the coercive force (X-axis) of the sintered magnet obtained by adding NdH ₂ as a sintering aid to the magnet powder prepared according to Example 1, homogeneously mixing, manufacturing a molded body, and then sintering. ) is a B_H graph showing

Referring to FIG. 5 , the magnetic flux density, coercive force, and maximum energy density of the sintered magnet obtained according to the manufacture of the sintered magnet of Example 1 can be confirmed. Specifically, the magnetic powder and NdH ₂ are homogeneously mixed in a graphite mold, minced with appropriate vibration, treated with a pulsed magnetic field to manufacture a molded body, and then PLP (Pressless Process) sintering first condition, added to the first condition The results obtained by the second condition of furnace post-annealing and the third condition of performing post-heat treatment after magnetic field molding and sintering of the manufactured molded body while applying pressure.

The curve obtained under the above three conditions does not have oversintering of grains (maintaining the angular ratio of the curve) and the maximum energy density also shows 30MGOe or less. 2 hours), the improvement of coercive force was observed while the magnetic flux density was maintained under the second and third conditions corresponding to the case of up to 2 hours, and it can be said that this is the most preferred embodiment. Although this level of performance is lower than that of conventional NdFeB sintered magnets (42SH; coercive force 12.4 kOe, magnetic flux density 1.28T), it can be applied in the middle area of fields where ferriat magnets and NdFeB-based magnets are applied respectively.

6 is a graph showing an XRD pattern of the magnet powder prepared according to Example 2. Referring to FIG.

Referring to FIG. 6 , the crystallinity of the magnet powder prepared according to Example 2 can be confirmed.

7 is a graph showing the M-H data of the magnet powder prepared according to Example 2.

Referring to FIG. 7 , in the case of the sintered magnet manufactured according to Example 2, a hysteresis curve of the NdFeB sintered magnet powder can be confirmed.

8 is a graph showing an XRD pattern after sintering the magnet powder prepared according to Example 2. Referring to FIG.

Referring to FIG. 8 , the degree of orientation in the (105) and (006) directions in the sintered magnet manufactured according to Example 2 can be confirmed.

9 is a graph showing the magnetic flux density and coercive force of the sintered magnet manufactured according to Example 2; Specifically, FIG. 9 is a B_H graph showing the magnetic flux density (Y-axis) according to the coercive force (X-axis) of the sintered magnet obtained by adding NdH ₂ as a sintering aid to the magnet powder prepared according to Example 2 and sintering.

Referring to FIG. 9 , the magnetic flux density, coercive force, and maximum energy density of the sintered magnet manufactured according to Example 2 can be confirmed.

In Examples 1 and 2 of the present invention, raw materials for forming a sintered magnet can be mixed, and then Nd-reduced magnet powder can be synthesized using a Ca reduction-diffusion method with a relatively low reaction temperature and a short reaction time, and a chemical synthesis method In the process of mixing and sintering crystalline [La, Ce] _1-x Nd _x ] ₂ Fe ₁₄ B particles and wet-milled NdH ₂ particles prepared by (oxidation-reduction), the difference in solid diffusion between Nd and La/Ce There is an advantage in that a (Nd, La, Ce) ₂ Fe ₁₄ B shell having a relatively large amount of Nd is formed on the grain surface by the Preferably, when comparing the performance of the sintered magnet through FIG. 5 related to Example 1 and FIG. 9 related to Example 2, it can be confirmed that the coercive force and magnetic flux density are higher in Example 1, which indicates that Nd (La , Ce), it can be confirmed that the method of adjusting the ratio of Nd, La, and Ce in the mother powder synthesis and adding an appropriate sintering aid during sintering is effective when manufacturing magnets.

Although preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements by those skilled in the art using the basic concept of the present invention as defined in the following claims are also provided. is within the scope of the

Claims (11)

[(La, Ce) _1-x Nd _x ] ₂ Fe _y B (x=0~0.5, y=12~13) mixing powder particle raw materials to prepare powder particles,
reacting the mixed powder particle raw material using a Ca reduction-diffusion method, and
Washing, pulverizing and drying the material formed by the reaction to prepare a magnetic powder,
The method of manufacturing a sintered magnet further comprising: after preparing a compact by mixing the manufactured magnet powder with NdH ₂ powder, heat-treating in a vacuum sintering furnace, cooling to room temperature in an argon atmosphere, and then performing post-heat treatment to sinter. In claim 1,
The step of mixing the powder particle raw material is
La ₂ O ₃ Powder A method for manufacturing a sintered magnet comprising mixing CeO ₂ powder and Nd ₂ O ₃ powder by a wet ball mill or a dry ball mill, and then mixing B, Cu/Al/Ga fluoride and Fe. In claim 2,
The step of reacting the raw material for powder particles includes mixing Ca after the step of mixing the raw material for powder particles. In claim 1,
The molded body is a sintered magnet manufacturing method in which 10 to 30% by weight of wet-pulverized NdH ₂ powder is added to the manufactured magnet powder. In claim 4,
A method for manufacturing a sintered magnet in which the manufactured magnet powder and the wet-pulverized NdH ₂ powder are mixed to prepare a compact and then heat-treated at 1000 to 1100 degrees Celsius. In claim 5,
In the heat-treated magnet powder, a nano-thick (Nd, La, Ce) ₂ Fe ₁₄ B shell is formed on the grain surface due to a difference in solid diffusion between Nd and La/Ce. In claim 6,
The content of Nd contained in the shell of the nano-thick (Nd, La, Ce) ₂ Fe ₁₄ B is greater than the content of Nd contained in the core of (Nd, La, Ce) ₂ Fe ₁₄ B formed in the center of the grains. How to make a magnet. In claim 5,
In the heat-treated magnet powder, a nano-thick (Nd, La, Ce) ₂ Fe ₁₄ B shell is formed on the grain surface due to the difference in solid diffusion between Nd and La/Ce, and the nano-thick (Nd, La, Ce) ) The thickness of the shell of ₂ Fe ₁₄ B is thinner than the thickness of the core of (Nd, La, Ce) ₂ Fe ₁₄ B formed at the center of the grains. Method of manufacturing a sintered magnet. In claim 4,
The method for manufacturing a sintered magnet wherein the NdH ₂ powder is wet-pulverized in a hexane atmosphere. delete La ₂ O ₃ powder CeO ₂ powder and Nd ₂ O ₃ powder are mixed by a wet ball mill or dry ball mill, followed by mixing B, Cu/Al/Ga fluoride and Fe;
reacting the mixed powder particle raw material using a Ca reduction-diffusion method;
washing, pulverizing and drying the material formed by the reaction to prepare a magnetic powder, and
After preparing a compact by adding 10 to 30% by weight of wet-pulverized NdH ₂ powder to the prepared magnet powder, heat treatment at 1000 to 1100 degrees Celsius to prepare a sintered body, and cooling to room temperature in an argon atmosphere, A sintered magnet manufactured by a sintered magnet manufacturing method comprising the step of sintering by performing a heat treatment afterward.

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