JPS61179801A - Alloy powder for bond magnet and its production - Google Patents

Abstract

PURPOSE:To obtain alloy powder for a bond magnet having excellent magnetic characteristics such as coercive force by press-molding pulverous powder consisting essentially of rare earth elements, B and Fe then disintegrating the molding and disintegrating further the same after heating. CONSTITUTION:12-20atom% >=1 kinds of rare earth elements such as Nd and Dy, 4-20% B and 60-84% Fe as essential components are melted and cast to obtain an ingot of which the main phase consists of a tetragonal crystal. The ingot is pulverized to the pulverous powder having <=15mum grain size. The pulverous powder is oriented in a magnetic field and is press-molded, then the molding is disintegrated to prescribed grain size. The disintegrated powder is heated at 800-1,000 deg.C and is thereafter disintegrated to obtain the pulverous powder having <=15mum grain size. Such pulverous powder consists of the aggregate powder having 100-1,000mum aggregate grain size and 5-15 KO8 coercive force.

Description

Detailed Description of the Invention Field of Application This invention relates to an alloy powder for permanent magnets whose main components are R (R is at least one rare earth element including Y), B, and Fe, and a resin or a nonmagnetic alloy. The present invention relates to an alloy powder for bonded magnets consisting of the following: and a method for producing the same.

BACKGROUND ART Current typical permanent magnet materials are alnico, hard ferrite and rare earth cobalt magnets.

As the raw material situation for cobalt has become unstable in recent years, demand for alnico magnets containing 20 to 30 wt% cobalt has decreased.
Inexpensive hard ferrite, whose main component is iron oxide, has come to dominate magnet materials.

On the other hand, rare earth cobalt magnets contain 50 to 60wt of cobalt.
% and S, which is not contained in rare earth ores very much.
Although it is very expensive because it uses m, it has much higher magnetic properties than other magnets, so it has come to be used mainly in small, high-value-added magnetic circuits.

Rare earth cobalt magnets are manufactured by a normal sintering method, but since grinding is required for commercialization, there is a problem of poor product yield, which further increases the price. To solve this problem, a bonding method has been proposed in which magnet powder is bonded and solidified with a resin or metal binder.

In addition, rare earth cobalt magnets have changed from RICos to R2C magnets.
Although high performance and resource saving have been achieved in the 0I7 series, even if the bonding method is used, expensive Sm and Co are the main components, and it is not a fundamental solution.

In order to solve the above problem, the applicant first developed an expensive S
Fs- as a new high-performance permanent magnet that does not contain m.
Proposed a B-R system (Rt, l: at least one rare earth element including Y) permanent magnet (Patent application 14507/1982)
No. 2), and in addition, Fa-B-R, which is optimal for bonded magnets.
system alloy powder (Japanese Unexamined Patent Publication No. 59-219904) was proposed.

The above alloy powder for Fs-B-R bonded magnets is 3, Jl obtained by mechanically crushing and finely crushing an ingot of the component.
Although the following fine powder is used, since the coercive force (iHC) of the alloy powder is about 3 kos, a high coercive force alloy powder has been desired in order to obtain a bonded magnet with even better magnetic properties.

Purpose of the Invention The present invention aims to improve the magnetic properties of a new bonded permanent magnet mainly composed of rare earth elements, boron, and iron, and provides an alloy powder for bonded magnets with excellent magnetic properties such as coercive force, and a method for producing the same. It is an object.

Structure and effect of the invention This invention provides R (R is at least one kind of rare earth elements including Y) 12 at % to 20 at %, B44 atoms to 20
It is composed of fine powder with a particle size of 15 terms or less, whose main component is Fe 60 atomic % to 84 atomic %, and whose main phase is a tetragonal phase, and has a coercive force (if-1c) of 5 kos to 15 koa.
This is an alloy powder for a bonded magnet, characterized in that it consists of an aggregate powder with an aggregate particle size of 1001a to 1000+, and further includes R (R is at least one of rare earth elements including Y).
Species) 12 atom% to 20 atom%, B44 atom to 20 atom%
A fine powder with a particle size of 151 s or less consisting of 60 at % to 84 at % of l"e as a main component and a main phase of tetragonal phase is crushed after being pressure-molded, further heated at 800 to 1100 ° C, and then disintegrated. An alloy powder for bonded magnets with excellent corrosion resistance characterized by being crushed to obtain an aggregate powder having an aggregate particle size of 100 Ia to 100 OJI and consisting of fine powder with a particle size of 15 JJn or less and having a coercive force (iHC) of 5 kOe to 15 kOe. This is the manufacturing method.

A method for manufacturing a bonded magnet using the alloy powder according to the present invention includes mixing with the alloy powder and molding.

A bonded magnet can be manufactured by appropriately selecting the type of binder used for assimilation or the like or the type of product, and the amount of binder is 50% or less in terms of volume composition in order to express the magnetic properties of the permanent magnet material.

Forming alloy powder without sintering and impregnating and solidifying it with a resin binder to make a bonded magnet, or mixing alloy powder with an alloy powder binder and forming it, and then heat-treating it after sintering to obtain a bonded magnet. I can do it. Further, as a molding method, in addition to normal press molding, injection molding, extrusion molding, and isostatic pressing can also be employed.

The synthetic resin used as the binder can be either thermosetting or thermoplastic, but thermally stable resins are preferred, such as polyamides, polyimides, phenolic resins, fluororesins, silicone resins, Epoxy resin etc. can be selected as appropriate. Further, in order to uniformly disperse and mix the alloy powder to exhibit magnetic properties, an alloy powder can also be used as a binder.

Furthermore, when using something other than synthetic resin as a binder, there are Cu, AI, and solder alloys such as TiH2,5nSPb, and in the case of alloys, they are used in powder form.

The bonded magnet using the alloy powder according to the present invention exhibits a maximum energy product (BH) maX of 108 GOe or more,
In the most preferable composition range, (BH)maX≧158G
Indicates Oa.

Reason for limitation of alloy powder and manufacturing method In this invention, the aggregate powder, which is the alloy powder for water-based bonded magnets, must be composed of fine powder with a particle size of 15 tEn or less, and if it exceeds 15 tEn, crystals of individual fine powders will form. Magnetic domains tend to occur within the grains, and magnetization reversal easily occurs, making it impossible to obtain a high coercive force. Furthermore, if the particle size is less than 0.5 μm, even if the surface area ratio increases, it will be easily oxidized and difficult to handle, so 0.5 μm to 15 μm is preferable.

In order to obtain good magnetic properties as a sintered permanent magnet, R
It is preferable that the composition has more R than the composition shown by the composition formula of 2F@t4B, and it is thought that it is necessary that the individual crystal grains made of the above-mentioned tetragonal compound be covered with a Nd-rich phase. . (Sagawa et, at
; J, Appl, Phys, 55(6), 15
March 1984) Therefore, it is considered that the compound having the tetragonal structure represented by the above composition formula and the Nd-rich phase control the magnetic properties of the water-based magnetic alloy.

The reason why fine powders after going through various pulverization processes exhibit a coercive force of at most about 2.0 kOa even within the above particle size range is that the individual crystal grains of the finely pulverized powders are rich in R. It is thought that it is not covered by phase.

In this invention, as described later, the particle size is 15. After pressure molding the fine powder below IS, it is crushed and further heated to 800℃~11
By heating at 00°C and then crushing, an aggregated powder in which individual crystal grains are surrounded by a Nd-rich phase is obtained.

In addition, the reason why the alloy powder with the above particle size is crushed after being pressed is to obtain a powder that has a high coercive force and is suitable for raw material powder for bonded magnets. It is coarsely pulverized powder (collection powder) of 100- to 1000-grade. Due to the heat treatment described below to form a eutectic between the R-rich phase and the basic composition, the fine m powder condenses and sinters, and when this is crushed,
The hard and brittle square compound is broken and the coercive force of the powder is reduced, but this aggregate powder is not sintered and bonded, and even if it is bonded, it can be easily loosened (crushed). .

Note that a magnetically anisotropic magnet can be obtained by press molding in a magnetic field during pressurization, and a magnetically isotropic magnet can be obtained by press molding in a non-magnetic field.

The purpose of heat treatment at 800°C to 1ioo°C and then crushing is to obtain a powder with high coercive force and suitable as raw material powder for bonded magnets.
A eutectic of a phase rich in R2Fats and a basic composition of R2Fats 8 is obtained. The above eutectic reaction occurs at around 680℃, but 7
To obtain a coercive force (iHc) of kOs+ or more, 800
Heating above ℃ is required. However, when the temperature exceeds 1100°C, sintering progresses even with coarsely pulverized powder (aggregated powder) of 100ρ to 10001M, making subsequent crushing difficult, grain growth occurs, and the coercive force decreases. Therefore, the heat treatment temperature is set at 800°C to 1io0°C.

Further, the heat treatment time is appropriately selected depending on the composition, particle size, etc.

In addition, after the above heat treatment, 500 ° C to 700 ° C, 0.5
When aging treatment is performed for ~20 hours, the coercive force is further improved.

The particle size of the aggregated powder after crushing changes due to temperature rise and heat treatment.
The particle size is required to be at least 100 JI or more in order to prevent sintering from proceeding and forming large lumps, to prevent the progression of oxidation of the chemically active water-based alloy fine powder, and to facilitate handling. However, when the particle size exceeds 1000 IJn, the moldability of the alloy powder for bonded magnets deteriorates, making it impossible to obtain a high filling rate. Therefore, the particle size of the aggregate powder is set from 100 Iin to i oooρ.

Reason for limiting alloy powder composition The rare earth element R of the alloy powder for bonded magnets of this invention is 1
2 atomic% to 20 atomic% Nd, Pr, No, Tb
At least one of the following, or in addition, La, Ce
, Gd.

Preferably, it contains at least one of Er and Y.

Further, one type of R is usually sufficient, but in practice, a mixture of two or more types (Mitsuhmetal, dididium, etc.) can be used for reasons such as convenience of availability.

Note that this R does not have to be a pure rare earth element, and may contain impurities that are unavoidable in production within an industrially available range.

R (at least one rare earth element including Y) is an essential element in the above-mentioned new alloy powder for bonded magnets, and if it is less than 12 atomic %, the crystal structure is a cubic crystal having the same structure as α-iron. If it exceeds 20 atomic %, R-rich non-magnetic phase increases and the residual magnetic flux density (Sr) decreases, making it difficult to obtain excellent properties. Bonded magnets cannot be obtained. Therefore, the rare earth element is in the range of 12 atomic % to 20 atomic %.

B is an essential element in the new alloy powder for bonded magnets of the above-mentioned type, and if it is less than 4 at%, it will form a rhombohedral structure and high coercive force (iHC) cannot be obtained, and if it exceeds 20 at%, The B-rich nonmagnetic phase increases, and the residual magnetic flux density (
Br) decreases, making it impossible to obtain excellent permanent VI1 stones. Therefore, B is in the range of 4 at.% to 20 at.%.

In the above-mentioned novel alloy powder for bonded magnets, Fe is
It is an essential element, and if it is less than 60 at%, the residual magnetic flux density (B
If r) decreases and exceeds 84 at %, a high coercive force cannot be obtained, so Fe is contained in an amount of 60 at % to 84 at %.

Moreover, in the alloy powder for bonded magnets according to the present invention,
Replacing a part of FB with 6 can improve the temperature characteristics of the resulting magnet without impairing its magnetic properties, and has the effect of improving the stability of the powder against oxidation, but co@ If the calibration exceeds 50% of FB, the magnetic properties will deteriorate, which is not preferable.

In the alloy powder of this invention, in order to obtain high residual magnetic flux density and high coercive force, R12.5 to 15 at%,
B66 atom to 14 atom%, Fe71 atom% to 82 atom%
is preferred.

In addition, the alloy powder for bonded magnets according to the present invention has R, B
In addition to FB, the presence of unavoidable impurities in industrial production can be tolerated, but a part of B can be replaced by 4.0 at% or less of C13, 5 at% or less of P, 2.5 at% or less of S, 3 By replacing at least one type of Cu with a total amount of 4.0 atomic % or less, it is possible to improve the productivity and reduce the cost of bonded magnets.

In addition, at least one of the following additional elements is R-BF
It is added to e-based bonded magnets because it is effective in improving the coercive force, etc., improving manufacturability, and reducing costs. However, the residual magnetic flux density (B
r), so it is desirable to add it in a range that is equal to or higher than the residual magnetic flux density of conventional hard ferrite magnets.

A1 of not more than 5.0 atomic %. Ding 115 of not more than 3.0 atomic %
．． 5 at% or less V, 4.5 at% or less Cr, 5, O
Mn of atomic % or less, B119 of 5.0 atomic % or less.
Nb of 0 atomic % or less, fine of 7.0 atomic % or less, 5.
2 at % or less No, 5.0 at % or less glue, 1.
Sb of 0 atomic % or less, Ge of 3.5 atomic % or less.

Sn of 1.5 atomic% or less, Zr of 3.3 atomic% or less
.

6.0 atomic% or less Ni, 5.0 atomic% or less 5i
13゜Contains at least one type of If of 3 atomic % or less. However, if two or more types are contained, the maximum content is 3 atomic % or less of the one with the maximum value. , it becomes possible to increase the coercive force of bonded magnets.

In addition, the alloy powder for bonded magnets of the present invention has a crystalline structure in which the main phase is a tetragonal crystal with at least 50 VO1% or more, and a nonmagnetic intermetallic compound with at least IVOI% or more.
Fine and uniform alloy powder is essential for producing bonded magnets with excellent magnetic properties.

Example 1m As a starting material, electrolytic iron with a purity of 99.9%, 819.4
A ferroboron alloy containing impurities such as FB, /V, SL, and C, and ceramic with a purity of 99.7% or more and ~ are used, and these are high-frequency melted in an Ar atmosphere.
After that, it was cast in a water-cooled copper mold, and 13Nd-2 to -8B-7
An ingot with a dendrite structure having a composition of 7Fe and a main phase of tetragonal crystals was obtained.

Thereafter, the ingot was coarsely ground to 35 meshes or less using a crusher, and then finely ground using a ball mill to obtain a fine powder with an average particle size of 3Is.

This fine powder is charged into a mold and oriented in a magnetic field for 1
．． It was pressurized at a pressure of 5 tons and 7 tons, and then crushed in a stamp mill to have a particle size of 200 to 500 particles.

The obtained powder was heated at 100° C. for 2 hours in Ar, and then subjected to aging treatment at 600° C. for 2 hours in Ar and crushed. The powder after heat treatment has an average particle size of 3
It is an aggregate powder with a particle size of 200I to 500IJm, which is agglomeration of fine powder of f, and has a coercive force (iHC) of 10.6 kOe.
Met.

The aggregated powder with the above properties was charged into a mold, oriented in a magnetic field of 10 kOe, and molded at a pressure of 2.0 t, J.
A molded body with dimensions of mm x width 10 wun x thickness 111 II m was produced.

Thereafter, the molded body was impregnated with a synthetic resin mainly composed of dimethaaglyate ester at 100°C.

A bonded magnet was obtained by heating and curing for 1 hour. The magnetic properties of this bonded magnet and the magnetic properties of the aggregated powder were measured and are shown in Table 1.

Also, for comparison, the above 13Nd-2Dy-8B-γ
An ingot with a composition of γFe was coarsely ground, then finely ground into a fine powder with an average particle size of 311 m, and charged into a mold to form a powder of 10 kOB.
2. oriented in a magnetic field; A molded body with dimensions of 14 mm in length, 10 mm in width, and 11 mm in thickness was produced by molding at a pressure of 700°C, and the molded body was impregnated with a synthetic resin whose main component was dimethaaglyate ester, and heated at 100°C for 1 hour. A bonded magnet was obtained by heating and curing. The magnetic properties of this comparative example bonded magnet and the magnetic properties of the comparative example alloy powder were measured, and the first
Shown in the table.

As is clear from Table 1, it can be seen that the magnetic properties of the bonded magnet alloy powder and bonded magnet according to the present invention were significantly improved.

Table 1 and below margins Example 2 As a starting material, electrolytic iron with a purity of 99.9%, 819.4
A ferroboron alloy containing F8 and impurities such as M, SL, and C, with the remainder being impurities such as F8, M, SL, and C, is used, and ceramics with a purity of 99.7% or more and ~ are used, and these are high-frequency melted in an Ar atmosphere, and then cast in a water-cooled copper mold. 141'! i-1,5Dy-
An ingot with a composition of 7,513-77Fe and a dendrite structure with a tetragonal main phase was obtained.

Thereafter, the ingot was coarsely ground to 35 meshes or less using a crusher, and then finely ground using a ball mill to obtain a fine powder with an average particle size of 2.7 mesh.

This fine powder was charged into a mold, oriented in a magnetic field of 10 kOe and pressed at a pressure of 1.5° C., and then crushed in a stamp mill to give a particle size of 10()Is to 500IJn.

The obtained powder was heated at 10 Torr in an Ar air flow at 800
It was heated under the various temperature conditions shown in Table 2 for 1 hour at ~1060°C, then subjected to aging treatment at 600''G for 1 hour in Ar, and then dissolved again into aggregated powder with a particle size of 1 oo, m ~ 500ρ. Shattered.

The above aggregate powder was charged into a mold, oriented in a magnetic field of 10 koa, fixed with paraffin, and the magnetic properties of the powder were measured using a vibrating sample magnetometer. The measurement results are shown in Table 2.

Also, for comparison, to the above 14Nd-1,5-1,5
An ingot with a composition of B-γγ was coarsely crushed, then finely crushed to form a fine powder with an average particle size of 3 ㎡, and charged into a mold, and 10 ko
Oriented in a magnetic field of s and fixed with paraffin, iooor
r, heated under various temperature conditions shown in Table 2 for 1 hour at 800°C to 1060°C in an Ar stream, and then heated to 600°C in IAr.
The powder was aged for 1 hour, and its magnetic properties as a powder were measured using a vibrating sample magnetometer. The measurement results are shown in Table 2.

As is clear from Table 2, heat treatment alone is not sufficient;
It can be seen that the process of pressurizing and then crushing the fine powder as a pre-process is essential, and due to the synergistic effect of this process, the coercive force of the bonded magnet alloy powder according to the present invention was significantly improved.

Table 2 with blank space below σS = σ15 kOe μ1 Asahi As starting material, electrolytic iron with a purity of 99.9%, 819.4
% and the remainder is Fθ and impurities such as Ml, SL, and C. A ferroboron alloy with a purity of 99.7% or more and ~, Co is used, and these are high-frequency melted in an Ar atmosphere, and then placed in a water-cooled copper mold. 14Nd-2Dy-
An ingot with a composition of 8Co-7B-69Fe and a dendrite structure with tetragonal crystals as the main phase was obtained.

After that, the ingot was coarsely crushed to 35 meshes or less using a crusher, and then finely crushed using an attritor while varying the crushing time to an average particle size of 1011 m,
A fine powder of 5 ml and 3 AM was obtained.

This fine powder is charged into a mold, and while oriented in a magnetic field of 10 koa, it is pressed and molded under a pressure of about 100 ml, and then crushed on a mesh to form an aggregated powder with a particle size of 10 to 500 particles. did.

The obtained aggregate powder was heated at 10-3 Torr in vacuum, a
Heating under various temperature conditions from OO℃ to 1060℃ for 1 hour,
Thereafter, it was subjected to aging treatment at 600° C. for 1 hour in Ar, and crushed again into aggregate powder with a particle size of 1001 En to 500 Jin.

The above aggregated powder was charged into a mold, oriented in a 10 kOe magnetic field, fixed with paraffin, and the coercive force of the powder was measured using a vibrating sample magnetometer. The measurement results are shown in Figure 1.

Also, for comparison, the above 14Nd-2Dy-8C
An ingot with a composition of o-7B-69Fe was coarsely ground and then finely ground into a fine powder with an average particle size of 10JI, 5JI, 3Is, and this fine powder was charged into a mold and heated in a magnetic field of 10 kOe. While oriented, it is press-molded at a pressure of 1 t, d, and then crushed on a mesh to obtain a particle size of 100 μm to 500 μm.
m aggregated powder, charged into a mold without heat treatment, oriented in a 10 kOe magnetic field and fixed with paraffin, and the coercive force of the powder was measured using a vibrating sample magnetometer.

The measurement results are shown in Figure 1.

As is clear from Fig. 1, the process of crushing the fine powder after pressurizing it is not enough, and heat treatment is essential. It can be seen that there has been a significant improvement.

[Brief explanation of drawings]

FIG. 1 is a graph showing the relationship between heat treatment temperature and coercive force in Example 3. Applicant: Sumitomo Special Metals Co., Ltd. Figure 1 Heat treatment temperature ("C) Voluntary Procedures Negosho March 6, 1985 Imperial Rescript 1985 Patent Application No. 20747 2, Title of Invention Alloy powder for bonded magnets and its Manufacturing method 3, relationship with the person making the amendment Applicant address: 5-22 Kitahama, Higashi-ku, Osaka Name: Sumitomo Special Metals Co., Ltd. 4, Agent 5, “Name of the invention” and “Patent claim” in the specification to be amended Column 6 of "Scope of the invention", "Detailed description of the invention", "Brief description of the drawings", Contents of amendment ■The entire text of the specification will be amended as shown in the attached sheet. “Title of the invention”, “Claims”, Description 1, Title of the invention: Alloy powder for bonded magnets and its manufacturing method 2, Claims IR (R is at least one rare earth element including Y) )
12 atom% to 20 atom%, B44 atom to 20 atom%, l
``The main component is e60 atomic% to 84 atomic%.
. It is composed of fine powder with a particle size of 15IIm or less, whose phase is a tetragonal phase, and has a coercive force (iHc) of 5 kOe to 15 kO.
An alloy powder for bonded magnets, characterized in that it consists of an aggregate powder having an aggregate particle size of 100 to 1000 particles. 2R (R is at least one rare earth element including Y)
12 atom% to 20 atom%, B44 atom to 20 atom%, F
A fine powder with a particle size of 15Is or less whose main component is e60 @ 84 atomic % and whose main phase is a tetragonal phase is crushed after being pressure-molded, and further heated at 800°C to 1100°C and then crushed. A method for producing an alloy powder for bonded magnets, which comprises obtaining an aggregate powder composed of fine powder with a particle size of 15 mm or less and having an aggregate particle size of 100 to 1000 Is and having a coercive force (iHc) of 5 kOe to 15 kOe. 3. Detailed Description of the Invention Industrial Field of Application This invention relates to an alloy powder for permanent magnets whose main components are R (R is at least one rare earth element including Y), B, and Fe, and a resin or a nonmagnetic alloy. The present invention relates to an alloy powder for bonded magnets consisting of the following: and a method for producing the same. BACKGROUND ART Current typical permanent magnet materials are alnico, hard ferrite and rare earth cobalt magnets. As the raw material situation for cobalt has become unstable in recent years, demand for alnico magnets containing 20 to 30 wt% cobalt has decreased.
Inexpensive hard ferrite, whose main component is iron oxide, has come to dominate magnet materials. On the other hand, rare earth cobalt magnets contain 50 to 60wt of cobalt.
% and S, which is not contained in rare earth ores very much.
Although it is very expensive because it uses m, it has much higher magnetic properties than other magnets, so it has come to be used mainly in small, high-value-added magnetic circuits. Rare earth cobalt magnets are manufactured by a normal sintering method, but since grinding is required for commercialization, there is a problem of poor product yield, which further increases the price. To solve this problem, a bonding method has been proposed in which magnet powder is bonded and solidified with a resin or metal binder. In addition, rare earth cobalt magnets are available from RICO5 to R2C
Although high performance and resource saving have been achieved in the 0I7 series, even if the bonding method is used, expensive Sm and Co are the main components, and it is not a fundamental solution. In order to solve the above problem, the applicant first developed an expensive S
Fe- as a new high-performance permanent magnet that does not contain m or m
proposed an 8R-based permanent magnet (R is at least one rare earth element including Y) (Japanese Patent Application No. 145072/1982);
Furthermore, we proposed an Fe-B-R alloy powder (Japanese Patent Application Laid-Open No. 59-219904) that is optimal for bonded magnets. The above FeBR alloy powder for bonded magnets is a 3ρ alloy powder obtained by mechanically crushing and finely crushing an ingot of the component.
Although the following fine powder is used, since the coercive force (iHc) of the alloy powder is about 3 koθ, a high coercive force alloy powder has been desired in order to obtain a bonded magnet with even better magnetic properties. Purpose of the Invention The present invention aims to improve the magnetic properties of a new bonded permanent magnet mainly composed of rare earth elements (boron and iron), and provides an alloy powder for bonded magnets with excellent magnetic properties such as coercive force, and a method for producing the same. It is an object. Structure and effect of the invention This invention provides R (R is at least one kind of rare earth elements including Y) 12 at % to 20 at %, B44 atoms to 20
It is composed of fine powder with a particle size of 15ρ or less, whose main component is Fe 60 atomic % to 84 atomic %, and whose main phase is a tetragonal phase, and has a coercive force (it-1c) of 5 kOe to 15 koa.
An alloy powder for bonded magnets, characterized in that it consists of an aggregate powder with an aggregate particle size of 1 oo and n-1 ooo,
Furthermore, the main phase is a tetragonal product whose main components are R (R is at least one of rare earth elements including Y) 12 at% to 20 at%, B44 to 20 at%, l"e60 at% to 84 at%. A fine powder with a particle size of 15 or less consisting of a phase with a crystal structure of
It is heated at 1100°C and then crushed, and is composed of fine powder with a particle size of 15- or less, and has a coercive force (it-+c) of 5 koa ~
This is a method for producing an alloy powder for a bonded magnet with excellent corrosion resistance, which is characterized by obtaining an aggregate powder having an aggregate particle size of 100 um to 1,000 koa and having a particle size of 15 koa. A method for manufacturing a bonded magnet using the alloy powder according to the present invention includes mixing with the alloy powder and molding. A bonded magnet can be manufactured by appropriately selecting the type of binder used for assimilation or the like or the type of product, and the amount of binder is 50% or less in terms of volume composition in order to express the magnetic properties of the permanent magnet material. Forming alloy powder without sintering and impregnating and assimilating a resin binder to form a bonded magnet, or mixing alloy powder with an alloy powder binder and forming it, and then heat-treating it after sintering to obtain a bonded magnet. I can do it. Further, as a molding method, in addition to normal press molding, injection molding, extrusion molding, and isostatic pressing can also be employed. The synthetic resin used as the binder can be either thermosetting or thermoplastic, but thermally stable resins are preferred, such as polyamides, polyimides, phenolic resins, fluororesins, silicone resins, Epoxy resin etc. can be selected as appropriate. Further, in order to uniformly disperse and mix the alloy powder to exhibit magnetic properties, an alloy powder can also be used as a binder. In addition, when using something other than synthetic resin as a binder, there are Cu, AI, and solder alloys such as TLH2,5nSpb, and in the case of alloys, they are used in powder form. The bonded magnet using the alloy powder according to the present invention exhibits a maximum energy product (BH)llIaX of 108 GOe or more, and in the most preferable composition range, (BH)maX≧15
8GOa is shown. Reason for limitation of alloy powder and manufacturing method In this invention, the aggregate powder, which is the alloy powder for water-based bonded magnets, must be composed of fine powder with a particle size of 15XrI or less, and if it exceeds 151XrI, individual fine powder crystals will form. Magnetic domains tend to occur within the grains, and magnetization reversal easily occurs, making it impossible to obtain a high coercive force. Further, if the particle size is less than 0.5 μm, the surface area ratio increases and it becomes easy to oxidize and becomes difficult to handle, so it is preferably 0.5 m to 15 m. In order to obtain good magnetic properties as a sintered permanent magnet, R
It is preferable that the composition has more R than the composition shown by the composition formula of 2Fe12B, and it is thought that it is necessary that each crystal grain made of the above-mentioned tetragonal compound be covered with a Nd-rich phase. (sagaWa et,
al; J, 81)l)1. Phys, 5
5(6), 15 March 1984) Therefore, it is considered that the compound having the tetragonal structure represented by the above composition formula and the Nd-rich phase control the magnetic properties of the water-based magnetic alloy. The reason why the fine powder after going through various crushing processes shows only a coercive force of about 2.0 kOe even if it is within the above particle size range is because the individual crystal grains of the finely crushed powder are rich in R. This is thought to be because it is not covered by the phase. In this invention, as will be described later, fine powder with a particle size of 15 or less is pressure-molded, then crushed, and then heated at 800°C to 1100°C.
By heating at °C and then crushing, an aggregated powder in which individual crystal grains are surrounded by a Nd-rich phase is obtained. In addition, the reason why the alloy powder with the above particle size is crushed after being pressurized is to obtain a powder that has a high coercive force and is suitable for raw material powder for bonded magnets. It is a coarse powder (aggregated powder) consisting of fine particles with a diameter of 100 μm to 1000 μm. The above-mentioned R-rich phase and basic phase R2Fa
Due to the heat treatment described below to form 1q of eutectic with t4B, the fine powder condenses and sinters, and when this is crushed, the hard and brittle tetragonal compound is broken and the coercive force of the powder decreases. However, this aggregated powder does not sinter and bond, and even if it does, it is easily loosened (crushed).
can do. Note that by applying a magnetic field in a certain direction during pressurization, alloy powder for magnetically anisotropic magnets can be obtained, and by press molding in the absence of a magnetic field, alloy powder for magnetically isotropic magnets can be obtained. A powder can be obtained. The purpose of heat treatment is to crush the powder after heating at aoo'c to 1100"C in order to obtain powder with high coercive force and suitable as a raw material powder for bonded magnets. and an intermetallic compound having a tetragonal structure, R
This is to obtain a eutectic with 2For4B. The above eutectic reaction occurs at around 680°C, but the coercive force (i
HC) requires heating to 800°C or higher. However, when the temperature exceeds 1100°C, from 1001tIn to 1
Sintering progresses even with coarse powder (aggregated powder),
Subsequent crushing becomes difficult, grain growth occurs, and the coercive force decreases. Therefore, the heat treatment temperature is set at 800°C to 1100°C. Further, the heat treatment time is appropriately selected depending on the composition, particle size, etc. In addition, after the above heat treatment, 500 ° C to 700 ° C, 0.5
When aging treatment is performed for ~20 hours, the coercive force is further improved. The particle size of the aggregated powder after crushing was limited in order to prevent sintering from progressing into large lumps due to temperature rise and heat treatment, and to prevent the progress of oxidation of the chemically active fine powder of this alloy. at least 100% to avoid
．． A particle size of gm or more is required. However, the particle size is 100
0. If it exceeds am, the moldability of the alloy powder for bonded magnets will deteriorate, making it impossible to obtain a high filling rate. Therefore, the particle size of the aggregate powder is from 100 mm to 100011 mm. Reason for limiting alloy powder composition The rare earth element R of the alloy powder for bonded magnets of this invention is 1
2 at% to 20 at% of Nd, Pr, HO, Tb
At least one of the following, or in addition, La, Ce
. Preferably, it contains at least one of Gd, Er, and Y. Further, one type of R is usually sufficient, but in practice, a mixture of two or more types (Mitsuhmetal, dididium, etc.) can be used for reasons such as convenience of availability. Note that this R does not have to be a pure rare earth element, and may contain impurities that are unavoidable in production within an industrially available range. R (at least one rare earth element including Y) is an essential element in the above-mentioned new alloy powder for bonded magnets, and if it is less than 12 atomic %, the crystal structure is a cubic crystal having the same structure as α-iron. If it exceeds 20 atomic %, the R-rich nonmagnetic phase will increase and the residual magnetic flux density (Br) will decrease, resulting in a bond with excellent properties. I can't get a magnet. Therefore, the rare earth element is in the range of 12 atomic % to 20 atomic %. B is an essential element in the above-mentioned new alloy powder for bonded magnets, and if it is less than 4 at%, it will form a rhombohedral structure and high coercive force (it-IC) cannot be obtained, and if it exceeds 20 at%, , B-rich nonmagnetic phase increases, and the residual magnetic flux density (Br) decreases, making it impossible to obtain an excellent permanent magnet. Therefore, B is in the range of 4 at.% to 20 at.%. 1"e is an essential element in the above-mentioned novel alloy powder for bonded magnets, and if it is less than 60 at%, the residual magnetic flux density (
If Br) decreases and exceeds 84 atomic %, high coercive force cannot be obtained, so Fe is contained in a range of 60 atomic % to 84 atomic %. Moreover, in the alloy powder for bonded magnets according to the present invention,
Replacing a part of F8 with Sn can improve the temperature characteristics of the resulting magnet without impairing its magnetic properties, and has the effect of improving the stability of the powder against oxidation. If the amount exceeds 50% of FB, the magnetic properties will deteriorate, which is not preferable. In the alloy powder of this invention, in order to obtain high residual magnetic flux density and high coercive force, R12.5 to 15 at%,
Preferably B66 to 14 atom% and l”e71 atom% to 82 atom%. In addition, the alloy powder for bonded magnets according to the present invention contains R, B
, In addition to Fe, the presence of unavoidable impurities in industrial production can be tolerated, but a part of B can be replaced by 4.0 atomic % or less of C13, 5 atomic % or less of P, 2.5 atomic % or less of S, 3 By replacing at least one type of CU with a total amount of 4.0 atomic % or less, it is possible to improve the manufacturability and lower the price of bonded magnets. Furthermore, at least one of the following additional elements is R-B-
It is added to Fs-based bonded magnets to improve their coercive force, improve manufacturability, and reduce costs. However, the residual magnetic flux density (
Since this causes a decrease in Sr), it is desirable to add it in a range that is equal to or higher than the residual magnetic flux density of conventional hard ferrite magnets. A1 of not more than 5.0 atomic %. Ding 115 of not more than 3.0 atomic %
．． 5 at% or less V, 4.5 at% or less Cr15.0
Hn below 5.0 atomic %, Bi below 9.0 atomic %, Nb below 7.0 atomic %, HO 15 below 5.2 atomic %, Glue below 0 atomic %, 1 Sb of .0 atomic % or less, Ge of 3.5 atomic % or less. Sn of 1.5 atomic% or less, Zr of 3.3 atomic% or less
. 6.0 at% or less Ni, 5.0 at% or less 5i13
．． Addition of at least one type of Hf of 3 atomic % or less; however, if two or more types are contained, the maximum content is 3 atomic % or less of the one with the maximum value among the added elements, so that the bond It becomes possible to increase the coercive force of the magnet. In addition, the alloy powder for bonded magnets of the present invention is characterized in that the main phase is a square product with a main phase of at least 50 VO1% or more, and a nonmagnetic intermetallic compound with at least IVOI% or more.
This is essential for producing bonded magnets with excellent magnetic properties. Examples Example 1 As a starting material, electrolytic iron with a purity of 99.9%, Ef19.
A ferroboron alloy containing 4% and the remainder consists of impurities such as FB, /V, SL, and C, ceramics and N with a purity of 99.7% or more are used, and these are high-frequency melted in an atmosphere.
After that, it was cast in a water-cooled copper mold and 13Nd-2Dy-88-
An ingot with a dendrite structure having a composition of 77F8 and a main phase of tetragons was obtained. Thereafter, the ingot was coarsely ground to 35 meshes or less using a crusher, and then finely ground using a ball mill to obtain a fine powder with an average particle size of 3βm. This fine powder is charged into a mold and oriented in a magnetic field for 1
．． It is pressurized with a pressure of 5 tJ, and then crushed with a stamp mill to obtain a particle size of 200 μm to 500 μm. I changed it to c+m. The obtained powder was heated at 1000° C. for 2 hours in Ar, and then subjected to aging treatment at 600° C. for 2 hours in Ar, and then crushed. The powder after heat treatment has an average particle size of 31
Particle size of fine particles of An aggregated from 200I to 50911m
It is an aggregated powder with a coercive force (iHC) of 10.6 kOa.
Met. The aggregated powder having the above properties was charged into a mold, oriented in a magnetic field of 10 koa, and 2. Formed at a pressure of 400 ft, then hydrostatically pressed into a shape with a length of 14 mm x width of 10 mm x thickness of 11 mm.
A molded body with dimensions of mm was produced. After that, the molded body is
A bonded magnet was obtained by impregnating the composite resin with a synthetic resin containing dimethaaglyate ester as a main component and curing it by heating at 100° C. for 1 hour. The magnetic properties of this bonded magnet and the magnetic properties of the aggregated powder were measured and are shown in Table 1. Also, for comparison, the above 13M-2Dy-8B-77
An ingot with a composition of F8 was coarsely crushed, then finely crushed to form a fine powder with an average particle size of 3 times, charged into a mold, oriented in a magnetic field of 10 kOe, and molded at a pressure of 2°01. Then, using a hydrostatic press, it was made into 14mm long x 10mm wide x 11mm thick.
A molded body with a size of
C. for 1 hour to obtain a bonded magnet. The magnetic properties of this comparative example bonded magnet and the magnetic properties of the comparative example alloy powder were measured and are shown in Table 1. As is clear from Table 1, it can be seen that the magnetic properties of the bonded magnet alloy powder and bonded magnet according to the present invention were significantly improved. Table 1 and below have margins. As starting materials for the fork barrel, electrolytic iron with a purity of 99.9%, B19.4
% and the remainder is Fe and impurities such as Ml, Si, C, etc. A ferroboron alloy with a purity of 99.7% or higher and ~ are used, and these are high-frequency melted in an Ar atmosphere, and then placed in a water-cooled copper mold. The ingot was cast to obtain an ingot with a composition of 14Nd-1,5DSi7.5[3-77Fa and a dendrite structure with tetragonal crystals as the main phase. Thereafter, the ingot was coarsely ground to 35 meshes or less using a crusher, and then finely ground using a ball mill to obtain a fine powder with an average particle size of 2.7 m. This fine powder was charged into a mold, and while oriented in a magnetic field of 10 koa, it was pressurized with a pressure of 1.5 t, J, and then crushed in a stamp mill to give a particle size of 1001s to 500 koa. The obtained lettuce powder was heated at 10 Torr in an Ar air flow, aOO
It was heated under the various temperature conditions shown in Table 2 at 1060°C to 1060°C for 1 hour, then aged in Ar at 600°C for 1 hour, and then crushed again into aggregated powder with a particle size of 100mm to 50011mm. The above aggregate powder was charged into a mold, oriented in a magnetic field of 10 kOa, fixed with paraffin, and the magnetic properties of the powder were measured using a vibrating sample magnetometer. The measurement results are shown in Table 2. In addition, as a comparison, the above 14Nd −1,5Dy −
An ingot with a composition of 7,5B-77Fa was coarsely crushed, then finely crushed to form a fine powder with an average particle size of 3 mm, charged into a mold, and
1001 by orientation and pressure molding in a magnetic field of 0 koa.
The material was classified into 500 Iin and heated under the various temperature conditions shown in Table 2 for 1 hour at 800°C to 1060°C in an Ar flow of 10 orr, and then aged at 600°C for 1 hour in Ar. After crushing, the powder was oriented again in a magnetic field of 10 koa, fixed with paraffin, and further magnetized in a pulsed magnetic field of 40 kos, and the magnetic properties of the powder were measured using a vibrating sample magnetometer. The measurement results are shown in Table 2. As is clear from Table 2, heat treatment alone is not sufficient;
It can be seen that the process of pressurizing and then crushing the fine powder as a pre-process is essential, and due to the synergistic effect of this process, the coercive force of the bonded magnet alloy powder according to the present invention was significantly improved. Main line margin Table 2 (σS = σ15kOa) Example 3 As a starting material, electrolytic iron with a purity of 99.9%, 819.4
% and the remainder is Fe and impurities such as M, SL, and C. A ferroboron alloy with a purity of 99.7% or more M, ~, and Co is used, and these are high-frequency melted in an Ar atmosphere, and then placed in a water-cooled copper mold. 14Nd-2Dy-
An ingot with a dendrite structure having a tetragonal crystal as a main phase was obtained with a composition of 8Ca-7B-69Fs. After that, the ingot was coarsely crushed to 35 meshes or less using a crusher, and then finely crushed using an attritor while varying the crushing time to obtain an average particle size of 110Al, 51
A fine powder of sI, 3 μm was obtained. This fine powder was charged into a mold and pressed under a pressure of 1t62 while being oriented in a magnetic field of 10 koa, and then crushed on a mesh to form an aggregated powder with a particle size of 100 to 5001 inches. The obtained aggregate powder was heated at 10-3 TOrr in vacuum at 80
It was heated under various temperature conditions of 0° C. to 1060° C. for 1 hour, then subjected to aging treatment at 600° C. for 1 hour in Ar, and crushed again into aggregate powder with a particle size of 100 Js to 500 Js. The above aggregate powder was charged into a mold, oriented in a 10 kos magnetic field, fixed with paraffin, and the coercive force of the powder was measured using a vibrating sample magnetometer. The measurement results are shown in Figure 1. Also, for comparison, the above 14t! i-2~-8Co
-7B An ingot with a 69Fs composition was coarsely crushed and then finely crushed to have an average particle size of 101M, 5J1. This fine powder was charged into a mold and pressed under a pressure of 1 tJ while oriented in a magnetic field of 10 koa, and then crushed on a mesh 1 to obtain a particle size of 1001a~ 5001s
I was made into an aggregated powder, charged into a mold without heat treatment, oriented in a magnetic field of 10 koθ, fixed with paraffin, and the coercive force of the powder was measured using a vibrating sample magnetometer. The measurement results are shown in Figure 1. As is clear from Fig. 1, the process of crushing the fine powder after pressurizing it is not enough, and heat treatment is essential. It can be seen that there has been a significant improvement. 4. Brief Description of the Drawings FIG. 1 is a graph showing the relationship between heat treatment temperature and coercive force in Example 3.

Claims (1)

[Claims] 1 R (R is at least one rare earth element including Y) 12 at % to 20 at %, B4 at % to 20 at %,
It is composed of fine powder with a particle size of 15 μm or less whose main component is Fe 60 atomic % to 84 atomic % and the main phase is a tetragonal phase, and the aggregate particle size is 100 μm to 1000 μm and has a coercive force (iHc) of 5 kOe to 15 kOe. An alloy powder for bonded magnets that is characterized by: 2 R (R is at least one kind of rare earth elements including Y) 12 atom% to 20 atom%, B4 atom% to 20 atom%,
A fine powder with a particle size of 15 μm or less consisting mainly of Fe 60 atomic % to 84 atomic % and the main phase being a tetragonal phase is pressure-molded and then crushed, further heated at 800 ° C to 1100 ° C and then crushed, A method for producing an alloy powder for bonded magnets, which comprises obtaining an aggregated powder composed of fine powder with a particle size of 15 μm or less and having a coercive force (iHc) of 5 kOe to 15 kOe and an aggregate particle size of 100 μm to 1000 μm.