JP2003297660A - Method for processing sm-fe-n-based magnetic powder for bond magnet and the bond magnet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for processing Sm-Fe-N-based magnetic powders for a bond magnet in which a flow property in forming the bond magnet is superior and moreover stability in kneading with a resin is excellent, and to provide the bond magnet. <P>SOLUTION: After iron oxide particle powders are mixed with samarium oxide particle powders, the mixture is subjected to a reduction reaction to form a mixture of iron particles and samarium oxide particles. Next, under a temperature range of 30 to 150°C and an oxygen containing atmosphere, a stabilization process is carried out to form an oxidated film on a particle surface of the iron particles. Thereafter, Ca is mixed, and under a temperature range of 800 to 1200°C and an inactive gas atmosphere, a reduction diffusion reaction is carried out, and next under a temperature range of 300 to 600°C, a nitriding reaction is carried out to obtain the Sm-Fe-N-based magnetic powders for the bond magnet. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a Sm-F for a bonded magnet, which is excellent in fluidity and kneading stability when forming a bonded magnet.
A method for producing an eN magnetic powder is provided.

[0002]

2. Description of the Related Art Bonded magnets have been widely used for various purposes such as electric products and automobile parts because of their advantages such as flexibility in shape and high dimensional accuracy. As the size and weight of the bonded magnet have been reduced, there is a strong demand for higher performance of the bonded magnet itself used for the magnet.

Generally, a bonded magnet is manufactured by kneading a binder resin such as a rubber or plastic material and a magnetic powder, and then molding the mixture. Therefore, in order to improve the performance of the bonded magnet, the magnetic powder is used. That is, there is a strong demand for a magnetic powder having high performance, that is, having a large residual magnetic flux density Br and a high coercive force iHc, and as a result, having a large maximum magnetic energy product (BH) max.

As magnetic powders, magnetoplumbite type ferrites such as barium ferrite and strontium ferrite, Sm-Fe-N type magnetic powders and rare earth-iron-boron type magnets are known. In particular, Sm-Fe-N
Recently, magnetic powders have attracted particular attention because they have a high saturation magnetization value and an anisotropic magnetic field and a high Curie temperature.

The Sm-Fe-N magnetic powder can be obtained by nitriding an alloy of samarium and iron, but it is necessary to grind it to an appropriate size for use in a bonded magnet. However, since it is difficult to obtain a uniform particle shape due to deterioration of magnetic properties through the pulverizing step, it is required to obtain Sm-Fe-N-based magnetic powder without pulverizing.

That is, regarding the residual magnetic flux density of the bonded magnet, it is important that a large amount of magnetic powder can be filled in the binder resin. Therefore, a magnetic powder having a uniform particle shape, an excellent particle size distribution, and an excellent fluidity is required.

Further, since the residual magnetic flux density of the bonded magnet depends on the saturation magnetization value of the magnetic powder, it is important that the magnetic powder has a high saturation magnetization value. For that purpose, Sm-Fe-N-based magnetic powder having excellent magnetic properties is required.

Furthermore, in the production of the bonded magnet, since the binder resin and the magnetic powder are heated and pressed during kneading, the magnetic powder is easily oxidized, and the binder resin is deteriorated due to the oxidation of the magnetic powder. Cheap. Therefore, there is a demand for an Sm-Fe-N-based magnetic powder that is resistant to oxidation and has excellent stability during kneading.

Conventionally, Sm has been obtained by using a raw material whose particle size is adjusted.
A technique for obtaining a —Fe—N-based magnetic powder is known (Japanese Patent Laid-Open Nos. 11-112216 and 11-31080).
No. 7, JP-A-11-335702, JP-A 20
No. 00-17309).

[0010]

The Sm-Fe-N magnetic powder for bond magnets, which is excellent in fluidity during formation of bond magnets and is excellent in stability during kneading, is currently most demanded. A method for producing Sm-Fe-N magnetic powder for bonded magnets having such characteristics has not yet been obtained.

That is, the above-mentioned respective publications describe adjusting the particle size of the iron raw material powder and adjusting the particle size of the mixture of the samarium raw material and the iron raw material, but suppressing sintering between particles. Therefore, it is difficult to carry out a uniform nitriding reaction.

[0012] Therefore, it is a technical object of the present invention to obtain an Sm-Fe-N-based magnetic powder having an excellent particle size distribution and a uniform particle shape, which is excellent in dispersibility and fluidity.

[0013]

The above technical problems can be achieved by the present invention as follows.

That is, according to the present invention, after the iron oxide particle powder and the samarium oxide particle powder are mixed, the mixture is subjected to a reduction reaction to obtain a mixture of iron particles and samarium oxide particles, and then at 30 to 150 ° C. Stabilization is performed in an oxygen-containing atmosphere in a temperature range to form an oxide film on the particle surface of the iron particles, and then Ca is mixed to 800 to 1200 ° C.
In the method for producing an Sm-Fe-N-based magnetic powder for a bonded magnet, the reduction diffusion reaction is performed in an inert gas atmosphere in the temperature range of 1 to 3, and then the nitriding reaction is performed in the temperature range of 300 to 600 ° C. is there.

The present invention also provides the above-mentioned Sm-for bonded magnets.
S for bonded magnets obtained by the method for producing Fe-N magnetic powder
A bonded magnet containing m-Fe-N magnetic powder.

The structure of the present invention will be described in more detail below.

Sm-Fe-N for bonded magnets according to the present invention
The method for producing the magnetic powders will be described.

The iron oxide particles in the present invention are preferably hematite particles or magnetite particles.

The particle shape of the iron oxide particle powder is spherical,
The average particle diameter is preferably 0.1 to 10 μm. When the average particle size is less than 0.1 μm, the volume of the oxide film in the stabilization treatment as a whole increases, which causes a violent exothermic reaction during the reduction-diffusion reaction in the next step, resulting in a uniform alloy composition and a sharp alloy composition. It becomes difficult to obtain an Sm-Fe-N-based magnetic powder having a particle size distribution. If it exceeds 10 μm, the particle size is large, and it becomes difficult to obtain an Sm—Fe—N-based magnetic powder having a target particle size. Further, it becomes difficult for Sm doping into the iron particles by the reduction diffusion reaction to evenly reach the inside of the particles,
Not desirable.

The particle size distribution of the iron oxide particles is iron oxide particles.
Cumulative body for particle size with 100% total volume of powder
When the product ratio is calculated, the cumulative volume ratio is 10%, 9
The particle size at the point of 0% is D₁₀, D₉₀As
If indicated, D₁₀Is 0.5 μm or more, D₉₀Is 8.0
It is preferably μm or less. If outside the range
Means that the particle size distribution is wide, and the obtained Sm-Fe
-The N-based magnetic powder has a broad particle size distribution and deteriorates magnetic properties.
It is not preferable because D₁₀And D₉₀Ratio D ₁₀/
D₉₀Is preferably 0.1 or more. This value is small
The good news is that the particle size distribution is wide and the result
Obtained Sm-Fe-N magnetic powder has low magnetic properties
It is not preferable because it is lowered.

Among the iron oxide particle powders, magnetite particle powders are prepared by reacting a ferrous sulfate aqueous solution with an alkaline aqueous solution to obtain a ferrous salt reaction solution containing a ferrous hydroxide salt colloid and adding an oxygen-containing gas. It can be obtained by aeration. The hematite particle powder can be obtained by heating and sintering the magnetite particle powder in the temperature range of 700 to 1000 ° C.

The particle shape of the samarium oxide particle powder in the present invention is granular, and the average particle diameter is 0.5 to 5.0 μm.
It is preferably m.

The mixing ratio of the iron oxide particle powder and the samarium oxide particle powder is Sm ₂ Fe, which is a stoichiometric ratio.
_An excess of samarium oxide is mixed so that samarium becomes 100 to 130 mol% in terms of Sm with respect to the ratio of Sm and Fe of ₁₇ .

The iron oxide particle powder and the samarium oxide particle powder may be mixed as long as the iron oxide particles and the samarium oxide particles can be uniformly contacted with each other.
Wet mixing or wet pulverization mixing using an attritor or the like is preferable.

The mixture of the iron oxide particle powder and the samarium oxide particle powder undergoes a reduction reaction to form a mixture of iron particles and samarium oxide particles. The reduction reaction can be carried out, for example, by heating in a temperature range of 500 to 700 ° C. under a hydrogen gas atmosphere.

In the present invention, it is important that the mixture of iron particles and samarium oxide particles is subjected to a stabilizing treatment to form an oxide film on the particle surface of the iron particles. By forming an oxide film on the particle surface of the iron particles, the nitriding reaction described below can be uniformly advanced, and sintering between particles can be suppressed.

In the stabilization treatment, a mixture of iron particles and samarium oxide particles is heated in an oxygen-containing atmosphere in the temperature range of 30 to 150 ° C. If the temperature is lower than 30 ° C., it is difficult to form a uniform oxide film, and it takes a long time for the treatment, which is not preferable. If it exceeds 150 ° C, the reaction may locally proceed, which is not preferable. The reaction time is about 1 to 5 hours.

The atmosphere for the stabilization treatment is an oxygen-containing atmosphere, and the oxygen content is preferably 30% by volume or less, more preferably 1 to 25% by volume.

The degree of the stabilization treatment can be calculated from the weight ratio of the oxide film by thermal analysis of the mixture after the stabilization treatment to measure the weight increase, as described later. The weight ratio of the oxide film of iron particles in the mixture is preferably 1 to 15% by weight. If it is less than 1% by weight, the effect of forming an oxide film is not obtained, and if it exceeds 15% by weight, the reduction-diffusion reaction in the subsequent step occurs violently, which is not preferable.

Calcium is mixed with the mixture of iron particles and samarium oxide particles after the stabilization treatment to carry out a reduction diffusion reaction.

The mixing ratio of calcium is preferably ₃ to 15 mol with respect to 1 mol of samarium oxide (Sm ₂ O ₃ ) in the mixture. When the amount is less than 3 mol, the reduction diffusion reaction is not sufficient and the reduction of samarium is insufficient. If it exceeds 15 moles, the effect is saturated and it is meaningless to add more than necessary.

The reduction-diffusion reaction is performed under an inert gas atmosphere at 8
It is performed in the temperature range of 00 to 1200 ° C. If the temperature is lower than 800 ° C, the reduction of samarium oxide will be insufficient. 1200
If the temperature exceeds ℃, evaporation of calcium and samarium begins to occur, the composition ratio is likely to change, and sintering is likely to proceed.

The mixture of iron particles and samarium oxide particles is made into an alloy of iron and samarium by carrying out a reduction diffusion reaction.

The alloy of iron and samarium after the reduction diffusion reaction is subjected to a nitriding reaction in the temperature range of 300 to 600 ° C. Thirty
When the temperature is lower than 0 ° C, it becomes difficult to inject a necessary amount of nitrogen into the alloy of iron and samarium. If it exceeds 600 ° C., decomposition of α-Fe and Sm into nitrides and the like starts, which is not preferable. The nitriding reaction time is about 1 to 20 hours.

The nitriding reaction was performed on Sm ₂ Fe ₁₇ by 2.
Performed so as to contain 8-3.5% by weight of nitrogen.

The Sm-Fe-N magnetic powder after the nitriding reaction can be taken out by washing with water, filtering and drying.

The obtained Sm-Fe-N-based magnetic powder for bonded magnets contains Sm ₂ Fe ₁₇ N ₃ as a main component, the particle shape is almost spherical, the particle surface is smooth, and the average particle diameter is 2. 0-6.0 μm, BET specific surface area value 0.10-
0.80 m ² / g, D _{10 of the} particle size distribution is 1.0 μm
As described above, it is preferable that D ₉₀ is 10.0 μm or less. D ₁₀ and the ratio _D 10 _{/ D 90} of the _{D 90} is preferably 0.10 or more.

The magnetic properties of the obtained Sm-Fe-N magnetic powder for bonded magnets (measured by orienting the powder in a magnetic field) are as follows: Coercive force 238.7 to 1428.6 kA / m.
(3000 to 18000 Oe), the residual magnetic flux density is 800 to 1300 mT (8 to 13 kG), and the maximum magnetic energy product is 79.4 to 396.8 kJ / m ³ (1
0 to 50 MGOe).

Next, the resin composition for a bonded magnet according to the present invention will be described.

The resin composition for a bonded magnet according to the present invention comprises Sm-Fe-N magnetic powder dispersed in a binder resin, and the Sm-Fe-N magnetic powder is 85-99. % By weight, the balance consisting of binder resin and other additives.

The binder resin can be variously selected depending on the molding method. A thermoplastic resin can be used in the case of injection molding, extrusion molding and calender molding, and a thermosetting resin in the case of compression molding. Can be used. Examples of the thermoplastic resin include nylon (PA) -based, polypropylene (PP) -based, ethylene vinyl acetate (EVA) -based, and polyphenylene sulfide (PPS).
A resin such as a resin, a liquid crystal resin (LCP), an elastomer, or a rubber can be used. As the thermosetting resin, for example, an epoxy resin, a phenol resin, or the like can be used.

In the production of the resin composition for a bonded magnet, a plasticizer, a lubricant, a coupling agent, etc. in addition to the binder resin are well known in order to facilitate the molding and bring out the magnetic properties sufficiently. You may use the additive of. Further, various magnet powders such as ferrite magnet powder can be mixed.

These additives may be selected appropriately according to the purpose, and as the plasticizer, commercially available products corresponding to the respective resins used can be used, and the total amount thereof is the bond used. 0.01-5.0% by weight to the agent resin
Degree can be used.

As the lubricant, stearic acid and its derivatives, inorganic lubricants, oils, etc. can be used, and about 0.01 to 1.0% by weight can be used with respect to the whole bonded magnet.

As the coupling agent, a commercially available product depending on the resin and filler used can be used, and about 0.01 to 3.0% by weight based on the binder resin used can be used.

As the other magnetic powder, ferrite magnet powder, alnico magnet powder, rare earth magnet powder and the like can be used.

The kneading stability of the resin composition for bonded magnets is
In the evaluation method described below, 20% or less is preferable. When the kneading stability exceeds 20%, when the magnetic powder is oxidized while heat and pressure are applied in the step of kneading the magnetic powder and the binder resin, the binder resin is chemically changed accordingly. It is not preferable because it deteriorates and the torque of the plastomill increases.

Flowability of resin composition for bonded magnet (MF
R) is 150 to 500 g / in the evaluation method described later.
About 10 minutes is desirable. When it is less than 150 g / 10 min, the moldability and productivity of injection molding are significantly reduced.

The resin composition for a bonded magnet according to the present invention is
The Sm-Fe-N-based magnetic powder is mixed with a binder resin and kneaded to obtain a resin composition for a bonded magnet.

The above-mentioned mixing can be carried out by a mixer such as a Henschel mixer, a V-shaped mixer, a Nauter, etc., and the kneading can be carried out by a uniaxial kneading machine, a biaxial kneading machine, a mortar type kneading machine, an extrusion kneading machine or the like. it can.

Next, the bonded magnet according to the present invention will be described.

Although the magnetic characteristics of the bonded magnet can be variously changed according to the intended use, the residual magnetic flux density is 350 to 800 mT (3.5 to 8.0 kG) and the coercive force is 238.7 to. 1428.5 kA / m (3000-
18000 Oe), and the maximum energy product is 23.9.
˜158.7 kJ / m ³ ( ^{3 to} 20 MGOe) is preferable.

The molding density of the bonded magnet is 4.5 to 5.0 g.
/ Cm ³ is preferable.

The bonded magnet according to the present invention is molded by a known molding method such as injection molding, extrusion molding, compression molding or calender molding using the above resin composition for a bonded magnet, and then magnetized by an ordinary method. It is possible to obtain a bonded magnet by pulse-magnetizing or.

[0055]

BEST MODE FOR CARRYING OUT THE INVENTION A typical embodiment of the present invention is as follows.

The degree of stabilization treatment in the present invention was calculated according to the following method.

That is, using thermogravimetric TG, 6 in air
The weight ratio of the oxide film was calculated by heating at 00 ° C. and measuring the weight increase. For example, in a mixture in which the Sm content is 110% with respect to the stoichiometric ratio of Sm ₂ Fe ₁₇ , if the weight increase due to oxidation is 29%, iron particles are calculated by the following calculation formula. The oxide film provided can be calculated to be about 7.0 wt% of the total iron particles.

The weight increase ratio is D, the ratio of Fe atoms contained in magnetite to the total Fe atoms in the iron particles is x, and Sm ₂
The mixing ratio of Sm to the stoichiometric ratio of Fe ₁₇ is z
As (z × 100 (%)), the magnetite weight ratio y in the iron particles was calculated according to the following formulas 1 and 2.

[0059]

[Formula 1] Weight increase ratio D:

[0060]

[Formula 2] Weight ratio of magnetite in iron particles y:

The shape of the Sm-Fe-N magnetic powder was observed with a scanning electron microscope.

The particle size distributions of the iron oxide particle powder and the Sm-Fe-N magnetic powder were measured by HELOS, and the cumulative ratio to the particle diameter was calculated when the total volume of each particle powder was 100% and the cumulative ratio was 10 %, 50% and 90% of the particle diameters are D ₁₀ , D ₅₀ (average particle diameter) and D, respectively.
_Shown as ₉₀ .

The magnetic characteristics of the Sm-Fe-N magnetic powder are as follows:
Wax and magnetic powder were placed in an acrylic capsule, heated and cooled while applying an orientation magnetic field to orient the magnetic powder, and then measured with a sample vibrating magnetometer VSM (manufactured by Toei Industry Co., Ltd.). Indicated.

The kneading stability of the resin composition for bonded magnets is
90.3 parts by weight of Sm-Fe-N magnetic powder, 8.2% by weight of 12 nylon resin, 0.5% by weight of antioxidant and 1.0% by weight of surface treatment agent were mixed using a Henschel mixer, Kneading with a twin-screw extrusion kneader (kneading temperature 190 ° C)
When the resulting composition was continuously kneaded with a plastomill for 120 minutes, the kneading torque was 0.2 kg · m.
And the minimum torque value (A),
Assuming that the torque value after 120 minutes is (B), [(B)
-(A)] / (A) × 100 (%).

Flowability of resin composition for bonded magnet (MF
R) is a semi-melt indexer (model 2A, manufactured by Toyo Seiki Co., Ltd.), and the heating temperature is 270 ° C and the load is 10 kgf.
It was measured under the conditions.

The magnetic properties of the bond magnet containing the Sm-Fe-N magnetic powder were measured by a BH tracer (Toei Kogyo Co., Ltd.) of the bond magnet molded in an oriented magnetic field.

Regarding the density of the bond magnet, after the molded bond magnet was sufficiently cooled to room temperature of about 25 ° C., the size of the bond magnet was measured, and the volume was determined from the measured value. Next, the weight of the molded bonded magnet was measured, and the weight value (g) was divided by the volume value.

<Production of Sm-Fe-N Magnetic Powder> Water, caustic soda and iron sulfate FeSO ₄ were charged in a predetermined amount into the reaction tank, the temperature was kept at 80 ° C., air was blown into the reaction solution to adjust the pH to 5. Then, reaction, synthesis and granular magnetite particles are obtained. Then, filter, wash with water, and dry, 800-1
Firing is performed in the atmosphere in the range of 000 ° C. After firing, it was crushed with a pin mill to obtain iron oxide particle powder.

The obtained iron oxide particle powder is hematite (α
A -Fe ₂ O _3), the particle shape is substantially close to the spherical shape, an average particle diameter of 1.31 .mu.m, _{D 1} 0 0.6 .mu.m of the particle size _{distribution,} a D 90 2.24μm, BET
The specific surface area value was 2.2 m ² / g.

<Wet Mixing> 3118.52 g of the iron oxide particle powder obtained here and samarium oxide (Sm ₂ O ₃ ,
Particle shape: granular, average particle size 4.40 μm) 881.4
8 g was wet mixed with water in an attritor. The obtained slurry was filtered, dried, and loosened to obtain a mixed powder.

<Reduction reaction and stabilization treatment> Next, 3000 g of the obtained mixed powder was charged into a rotary heat treatment furnace and heated at 600 ° C. for 5 hours while flowing hydrogen having a purity of 100% at 40 l / min. A reduction reaction was performed. After the reduction reaction, it was a mixture of iron particles and samarium oxide particles. Then, the atmosphere in the rotary furnace was replaced with N ₂ and the temperature was changed to 4
Cool to 0 ° C. When the temperature stabilizes, about 2.0
Stabilization treatment was performed for 1 hour under N ₂ flow containing vol% oxygen to gradually oxidize the particle surfaces of the iron particles and form an oxide film on the particle surfaces. After observing the heat of reaction, when the heat of reaction has subsided, the entire system is cooled to room temperature, the mixture is taken out into the air, and is loosened with a reiki to form an oxide film on the particle surface. A black powder was obtained. The oxide film formed on the iron particles was 7.0% by weight as magnetite in the iron particles.

<Reduction and diffusion reaction and nitriding reaction> 521.51 g of the black powder obtained here and 103.4 of granular metal Ca were added.
9 g (600 mol% with respect to Sm ₂ O ₃ ) is mixed, put in a tray made of pure iron, and inserted into an atmosphere furnace. After evacuation of the furnace, the temperature is raised to 1050 ° C. in an argon gas stream. When the temperature in the furnace reaches a predetermined temperature, it is then cooled to 450 ° C., and when the temperature stabilizes at 450 ° C., it is evacuated once and placed in a N ₂ gas stream. After being in a N ₂ stream, the temperature is maintained at 450 ° C. for 8 hours for nitriding reaction, and then cooled to room temperature.

<Washing / Drying> The powder after the nitriding reaction is poured into water. As a result, it spontaneously disintegrates in water and the separation of the alloy powder and the Ca component begins. By further mechanically crushing, the Ca component is washed with water into the aggregate. By repeating decantation several times, C
After removing the component a, it was filtered and dried in an N ₂ stream to obtain 500 g of Sm-Fe-N-based magnetic powder.

The obtained Sm-Fe-N magnetic powder had a spherical particle shape and a smooth particle surface, with an average particle diameter of 3.0 μm and a particle size distribution of D ₁₀ of 1.03 μm.
m, D ₉₀ is 5.70 μm, BET specific surface area value is 0.67
m was ² / g. Magnetic property is coercive force 897kA / m
(11300 Oe) and residual magnetic flux density is 1244 m
T (12.44 kG), and the maximum magnetic energy product was 222 kJ / m ³ (28.0 MGOe).

<Production of Resin Composition for Bonded Magnet> 90.3 wt% of Sm-Fe-N magnetic powder obtained here, 8.2 wt% of 12 nylon resin, 0.5 wt% of antioxidant and surface. 1.0% by weight of the treating agent was mixed using a Henschel mixer and kneaded with a twin-screw extrusion kneader (kneading temperature 190
C.) to obtain a resin composition for a bonded magnet.

The kneading stability of the obtained resin composition for bonded magnets was 3% according to the above-mentioned evaluation method, and MF showing fluidity was obtained.
R is 430g under the conditions of heating temperature of 270 ° C and pressure of 10kg.
It was / 10 min.

<Manufacture of Bonded Magnet> The obtained resin composition for a bonded magnet was injection-molded to prepare a bonded magnet.

The room temperature magnetic characteristics of the obtained injection-molded bonded magnet were as follows: residual magnetic flux density of 763 mT (7.63 kG), coercive force of 635 kA / m (8.01 kOe), and maximum magnetic energy product of 103 kJ / m ³ (13. 0MGOe) and the density was 4.76 g / cc.

[0079]

In the present invention, a mixture of samarium oxide and iron oxide particle powder is hydrogen-reduced and then stabilized to form an oxide film on the particle surface of the iron particles. By forming an oxide film on the particle surface of the iron particles, the oxide film layer of each iron particle generates heat during the reduction-diffusion reaction, and a uniform reduction-diffusion reaction can be performed as a whole, which enables uniform firing. It is estimated that it has become.

It is known that the particle shape and particle size distribution of the Sm-Fe-N system magnetic powder grow depending on the particle shape and particle size distribution of the starting material, especially iron oxide particle powder. In the present invention, by using the iron oxide particle powder having a uniform particle size distribution, the obtained Sm-Fe-N-based magnetic powder has a more uniform particle size distribution.

[0081]

EXAMPLES Next, examples and comparative examples will be given.

Examples 1 to 4 and Comparative Examples 1 to 4: Sm was carried out in the same manner as in the above-mentioned embodiment of the invention except that the average particle diameter and particle size distribution of the iron oxide particle powder and the conditions of the stabilizing treatment were variously changed. -Fe-N system magnetic powder was obtained.

The manufacturing conditions at this time are shown in Table 1, and the obtained S
Table 2 shows various characteristics of the m-Fe-N magnetic powder. In addition,
The weight% of the oxide film for the stabilization treatment is the weight ratio of magnetite in the iron particles with respect to the magnetite (oxide film) formed on the particle surface of the iron particles.

[0084]

[Table 1]

[0085]

[Table 2]

Sm-Fe-N obtained in Examples 1 to 4
All of the magnetic powders have a substantially spherical particle shape,
The particle surface was smooth.

Examples 5-8, Comparative use examples 5-8: Sm-
A bonded magnet was obtained in the same manner as the embodiment of the present invention except that the Fe-N magnetic powder was variously changed.

Table 3 shows the manufacturing conditions and various characteristics of the bonded magnet at this time.

[0089]

[Table 3]

[0090]

EFFECT OF THE INVENTION Sm-Fe- for bonded magnets according to the present invention
Since the Sm-Fe-N-based magnetic powder for bonded magnets having excellent fluidity and kneading stability can be obtained by the method for producing N-based magnetic powder, it is suitable as a method for manufacturing Sm-Fe-N-based magnetic powder for bonded magnets. Is.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Masanori Hirata             Toda Kogyo Co., Ltd. 1-4 Meiji Shinkai, Otake City, Hiroshima Prefecture             In ceremony company Otake creation center (72) Inventor Norio Sugita             Toda Kogyo Co., Ltd. 1-4 Meiji Shinkai, Otake City, Hiroshima Prefecture             In ceremony company Otake creation center F term (reference) 4K017 AA04 BA06 BB12 CA01 CA07                       DA04 EH18 FB10                 5E040 AA11 AA19 BB03 BC08 CA01                       HB07 HB09 HB11 HB14 HB17                 5E062 CD05 CG03 CG07

Claims (2)

[Claims] 1. An iron oxide particle powder and a samarium oxide particle powder are mixed, and then the mixture is subjected to a reduction reaction to form a mixture of iron particles and samarium oxide particles, and then 30
~ 150 ° C in a temperature range of oxygen-containing atmosphere to perform a stabilizing treatment to form an oxide film on the particle surface of the iron particles, and then mix with Ca in a temperature range of 800 to 1200 ° C in an inert gas atmosphere. The reduction diffusion reaction is carried out at
A method for producing an Sm-Fe-N-based magnetic powder for a bonded magnet, which comprises performing a nitriding reaction in a temperature range of 0 to 600 ° C. 2. The Sm—Fe for bonded magnet according to claim 1.
-Sm for bonded magnets obtained by the method for producing N-based magnetic powder-
A bonded magnet containing Fe-N magnetic powder.