JPS63114939A - R2t14b-type composite-type magnet material and its production - Google Patents

Abstract

PURPOSE:To improve corrosion resistance and dimensional yield, by sintering a powder mixture of a matrix-material powder and an R2R14B-type magnetic powder in a specified volume ratio so as to form a sintered compact in which the grain boundaries of magnetic crystalline grains are coated with a matrix phase. CONSTITUTION:An ingot consisting of R2T14B-type magnetic crystals (where R means Y and rare earth elements and T means transition elements) is crushed to the formula into an R2T14B-type magnetic powder. On the other hand, a matrix-material powder consisting of low-m.p. metal such as Al, Zn, etc., or high-m.p. metal such as Fe, Co, etc., is prepared. Subsequently, <=10%, by volume ratio, of the matrix-material powder is mixed with the above magnetic powder as the balance to be formed into a powder mixture. This powder mixture is compacted in a magnetic field, and the resulting green compact is subjected to sintering at a temp. lower than the peripectic temp. (about 1,140-1,150 deg.C) of the magnetic powder and higher than the m.p. of the matrix material or, after the above compacting, subjected to hot working such as HIP, etc., at a temp. lower than 1,100 deg.C. In this way, the magnetic crystalline grains are dispersed in the matrix phase and, as a result, grain boundary layers excellent in oxidation resistance can be formed on the surfaces of the magnetic crystalline grains.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an R*T+4B composite magnet material and a method for manufacturing the same.

[Conventional technology]

In recent years, as industrial technology has become more sophisticated, the uses of permanent magnets that have an electrical energy/mechanical kinetic energy conversion function have expanded, and there is a demand for higher efficiency in this function.

In line with this trend, demand for Sm-Go rare earth magnets (SmCos, Sm2Co+ series), which have a much larger energy product than conventional alnico magnets and ferrite magnets, has increased dramatically.

However, due to insufficient production of Sm metal and unstable supply of Co, there are concerns about the stable supply of Sm-Co rare earth magnets, and there is a desire for magnets with a better energy product. Therefore, many studies have been conducted on the possibility of using light rare earth element-iron magnets, which are abundant in resources and have high saturation magnetization.

However, in general, R-T-B (here, R is a rare earth element containing Y, and T is a transition metal) system rare earth element-iron compound has a Curie temperature lower than room temperature, and the direction of easy magnetization is uniaxial. Therefore, it has been difficult to create -axial crystal anisotropic magnets (1).

Therefore, N, C, Koon and B, N, Dasba, super rapid cooling (Feo, sJo, 18) +1. qTbo,
We have discovered that by heat-treating the O3 band (amorphous) at 925° C., it can be crystallized and exhibits permanent magnetic properties at room temperature.

This is an R-Fe compound (
By adding B to R: rare earth element), it becomes a magnetic crystal with uniaxial magnetization at room temperature, and the chemical properties of each element in the rare earth series are similar to each other.
), this is N,F,Chabon+Yu.

B, Kufma, N, S, B11onizhko,
O20, Kachman, N.V.

R-Fe-B (R=Gd, S
m, Nd) When applied to the ternary system phase diagram +4),
As shown in Figure 10, this magnetic compound is composed of R, Fe,
, 6B compound (second half, RJe+4 by precise structural analysis
It is estimated that it was found to be B (5)).

Therefore, from the relationship between the saturation magnetization of rare earth element-transition metal compounds and the type of rare earth element, Fe-B-R (R=Ce, Pr, Nd) compounds are more permanent magnets than Fe-B-La-Tb. It can be inferred that the characteristics are improved.

J. J. Croat confirmed that by rapidly cooling a molten Nd or Pr-Fe-B to form a single band, it exhibits permanent magnetic properties (6). It is said that the origin of the permanent magnetic properties lies in the structure in which NdzFe+ aB particles with a size of 2 Or+n+ to 30 nm are dispersed in an amorphous Fe phase ()).

However, although the value of this ribbon as a resin-bonded magnet is recognized, since the crystals have no orientation, it is only an isotropic magnet and cannot be given anisotropy, and its characteristics are anisotropic Sm It does not even exceed that of the -Co resin bonded magnet.

Therefore, Sayo, Fujiwara, and Matsuura have conventionally developed Sm-C based on the idea that "permanent magnetic properties are improved by orienting crystal grains" suggested by N. C. Koon et al.

By applying a powder metallurgy method (9) widely used for sintered magnets, we proposed an anisotropic Nd-Fe-8 magnet with high magnetic properties that surpass those of Sm-Co magnets. The source of this magnet's permanent magnetic properties is to first make the alloy composition richer in Nd than Nd2Fe+J, and obtain a dense sintered body using liquid phase sintering (9), which is used in the production of Sm-Co5. Furthermore, the magnet structure always contains a rare earth-rich phase (approximately 80 at%
(above)).

[Problem that the invention seeks to solve]

Since this Nd-rich phase is a solid solution of Nd-Fe, its physicochemical properties are essentially similar to those of pure Nd,
Extremely active. Therefore, the presence of the zero phase significantly impairs the corrosion resistance of the alloy, and it has the disadvantage that it can hardly be used in the environment in which general permanent magnet materials are used.

An object of the present invention is to provide a manufacturing method.

In addition, in the case of the sintering method, the product dimensions in the process are controlled by adjusting the dimensions of the compact, but the relative density of the compact is 50 to 60%, and the amount of sintering shrinkage is extremely large. As a result, the variation in product dimensions increases, and the sintered special high NdO liquid phase may not wet the solid phase sufficiently and seep out to the surface, or react with oxygen in the sintering atmosphere to form an oxide layer. Because of the formation of a surface layer with poor properties such as smearing, there is also a limit to the yield for forming the final product shape using the final method.

It is to provide.

[Summary of the invention]

Therefore, in order to solve the first and second technical problems described above, the present invention essentially consists of a matrix material powder of 10% or less in volume composition ratio and an R1Tl4B magnetic powder constituting the remainder. The mixed powder or a preformed compact of the mixed powder is hot pressed or sintered so that the interface of the magnetic crystal grains is at the peritectic temperature of the RgTtJ magnetic powder (RZT14B crystals). If the element or compound has a melting point lower than the temperature at which it decomposes into T and liquid phase when heated: 1140 to 1150°C (referred to as a low melting point phase), it can be made into an ordinary powder or magnetic powder by physical and Any material that forms a chemical surface coating layer may be used.

On the other hand, if the matrix material is an element or compound having a melting point higher than the peritectic temperature of the IhTtJ magnetic powder (referred to as a high melting point layer), ultrafine powder with an average particle size of 2.0 to 1000 nanometers is used. Any material may be used as long as a desired molded article can be obtained.

That is, in the forming process, as shown in Figure 1, the purpose is for the matrix phase to uniformly bond individual magnetic crystal grains to form a dense composite structure, without changing the structure of the magnetic crystal grains. Excellent corrosion resistance can be obtained by using elements with excellent corrosion resistance as components and forming an intermetallic compound matrix phase with excellent corrosion resistance.

In addition, in order to obtain the above R, T, B-based composite magnet,
Conventional powder metallurgy techniques can be applied.

In other words, when using a sintered body, basically the conventional SmC
There is no particular difference from the case of o-based magnets, but from the perspective of using the liquid phase sintering method, a low melting point phase alloy was used as the matrix material, and the magnetic crystal particles and matrix phase were separately made into ingots and crushed. Only one mixing step is added later. Exactly the same method as conventional methods can be used to crush magnetic crystals, but since many of the low-melting metal elements are highly ductile and malleable and difficult to crush in matrix phase alloys, it is difficult to crush them using the spray method. Alternatively, if it contains rare earth elements, it may be pulverized by hydrogen embrittlement. In addition, an ordinary device such as a ball mill can be used to mix the magnetic crystal phase particles and the matrix phase powder.

On the other hand, the hot pressing method uses a product-shaped mold, which eliminates the cutting process, and because the molding process is done in a closed system, there is no need to remove the surface oxidation layer. It has the feature of improving dimensional yield. In this case, any of the so-called hot pressing, hot isostatic pressing, extrusion molding, etc. can be used. In order to obtain a more excellent anisotropic magnet, it is possible to magnetize it using an orientation magnetic circuit installed in a pressure molding machine or the like, or to press-form the mixed powder in advance in a magnetic field and mold it into a preform. After that, it is preferable to perform the above-mentioned hot pressing or the like.

The present manufacturing method and the alloy composition of the magnet material will be specifically described below.

First, the R2T, 4B magnet materials to which the present invention is applied are:
It is expressed by the general formula %. R in the formula is a rare earth element, and Sc.

Y, La, Ce, Pr, Nd, Pm, Sm
l Eu+ Gdl Tbl Dy+Ho+ Er+
One or more of Tm, yb, and Lu are used. M in the formula is an element or compound that forms a matrix phase. In the low melting point phase, Zn+ AN 1 S+ In, Ga, Ge, S
One or more of n, Te, Cu, and R7, or a low melting point compound of these elements and at least one element selected from rare earth elements, Fe, and B is used.

On the other hand, in the high melting point phase, Fe, Co+ Ni+
One or more kinds of Cr, or a high melting point compound of these elements and at least one element selected from rare earth elements, Fe, and B is used. In this case, the matrix material powder used is an ultrafine powder with an average particle size of 20 to 1,000 nanometers.

In addition, in formula 0, the component ratio of magnetic crystal particles is 0.6
5≦m≦0.85, 0.05≦n≦0.15. F
If the amount of eO is too large, the residual magnetic flux density Br will improve, but the coercive force (Hc) will be extremely reduced, and if the amount is too small, the Br
0.65≦m≦0.85 because the maximum energy product (8N) max decreases. B has a remarkable effect on improving the magnetic properties, but since the amount added causes deterioration of the properties, it was set to 0.05≦n≦0.15. Therefore, the component ratio of the magnetic crystal particles is 10 to 20 in atomic percentage.
% R, 5 to 15% B1, and the balance is preferably Pe.

Incidentally, a B Lynch phase may be precipitated in the magnet due to deviation of the weight value from the stoichiometric composition, but this does not impede the purpose of the present invention.

Here, the reason why the volume composition ratio of the matrix phase is set to 10% or less is that, although it is preferable to have a large amount of the matrix phase in order to uniformly cover the magnetic crystal grains, on the other hand, the saturation magnetization of the matrix phase is small. This is because it deteriorates the magnetic properties.

Next, the manufacturing method of the magnet material represented by the formula 0 is R1-
After producing a rare earth-iron magnetic material alloy ingot with the composition @-rF'emBn, it is crushed, mixed with a powdered matrix material, and preferably this mixed powder is press-molded in a magnetic field or without a magnetic field to prepare a preliminary material. After forming into a molded product, 300 to 11
5-5000kg/cut within the temperature range of 00°C
The desired molded product is obtained by hot pressing at a pressure of .

Here, the temperature during molding was set at 300 to 1100°C because if it is less than 300°C, the compact cannot be made denser by hot pressing, and if it is higher than 1100°C, the R-Fe-B magnetic crystal particles will not be formed. This is because grain growth and the reaction between the magnetic crystal particles and the elements of the matrix material become significant, making it impossible to obtain good magnetic properties. In addition, the hot pressing pressure is 5 kg/
If it is less than ct, the compact cannot be made dense, so 5kg/c.
It is desirable to set it to III or higher.

In addition, as mentioned above, hot press forming can be done by any of the so-called hot presses, hot isostatic presses, and extrusions, but the final product shape can be obtained directly and the cutting process is reduced compared to conventional methods. Or from the point of view that it can be deleted,
Hot pressing and extrusion are most suitable.

Therefore, when extrusion molding is performed, in order to make the molded product more dense, the preform formed by pressure molding the mixed powder is heated in advance to the melting point temperature of the low melting point phase (100 to 800°C), and then extrusion is performed. Preferably molded. Furthermore, in order to suppress the reaction between the goo used during extrusion molding and the preform, it is necessary to apply a heat insulating material such as a glass piece to the heated preform and perform extrusion molding. is desirable.

Here, the heating temperature of the preform was limited to the melting point temperature of the low melting point phase, because if the matrix material is melted at too high a temperature, the reaction with the magnetic crystal particles will be significant, resulting in poor magnetic properties. This is because it is not possible.

In addition, it is usually possible to obtain a molded body with some magnetic properties by subjecting the mixed powder to hot pressing, etc., but at this time, the gap between the molten matrix material layer and the individual magnetic crystal particles is In many cases, discontinuous boundaries (reverse magnetic domain generation sites) are partially generated, and these reverse magnetic domain generation sites prevent magnetic crystal grains from maintaining a fixed magnetic domain orientation.

Therefore, by further applying heat treatment to the molded body,
By further reducing the number of sites where such reversed magnetic domains occur while suppressing the diffusion reaction with the magnetic crystal grains, and by promoting a constant orientation of the magnetic domains, it is possible to improve the coercive force Hc of the compact as a result.

Furthermore, as shown in Fig. 2, the temperature of the reheat treatment of the compact is as follows:
The temperature is preferably 300 to 900°C.

At temperatures below 300°C, the effect of reducing the number of reverse magnetic domain generation sites is not significant, and at temperatures above 900°C, interdiffusion between the elements of the matrix material and the magnetic crystal grains occurs, conversely resulting in a decrease in the coercive force (1c). Because it will be.

In addition, as is clear from Figure 3, the reheat treatment time is as follows:
For example, in the case of reheat treatment at around 600°C, 10 to 4
A short time of 0 minutes is preferable.

Note that the high melting point phase alloy can be handled in the above manufacturing method in the same manner as the low melting point phase described above.

That is, it is considered desirable to use a low melting point phase in the matrix material in order to suppress the reaction with magnetic crystal particles as much as possible. Therefore, according to the present invention, even if the metal has a high melting point temperature (1140°C) (for example, Fe, Co+Ni, Cr, etc.), the average particle size can be reduced to 20 to 1
, 000 nanometers, the ratio of the specific surface area of the particles increases, so the driving force for mass transport increases. Furthermore, by combining this with hot pressing force, it is possible to obtain a dense molded body that is substantially the same as the low melting point layer.

Furthermore, since it is an ultrafine powder, it is possible to improve the uniform dispersibility of the matrix material in the magnetic crystal particles.

Note that even when the low melting point phase is made into ultrafine powder, the uniform dispersibility of the magnetic crystal particles can be improved.

Here, the average particle diameter of the high melting point metal was set to 20 to 1,000 nanometers because it is difficult to obtain ultrafine powder of less than 20 nanometers industrially. Detailed description of the invention.

1.First embodiment- First, matrix material powder is mixed with a low melting point element (Zn.

A case in which hot pressing is performed using one of AA, Sn, and Pb will be explained.

The starting materials for the magnetic material include Nd with a purity of 98% or more, and Nd with a purity of 9
Using electrolytic iron with a purity of 9.9% or more and B with a purity of 99.5% or more, they were mixed into a composition of Nd13FellBl, melted in a high-frequency melting furnace in a controlled atmosphere, and melted in a crusher and a disc mill for 24 hours. It was coarsely ground to a mesh size or less, and then finely ground to an average particle size of 3 microns using a ball mill.

Then, as a matrix material, 5
wt% Zn 12W j%^l.

2wt% S, 5ivt% In, 4wt% G
a, 4Ivt% Ges 5wt% Sn, 4wt
% Te, 6 wt % Cu, and 7 wt % Pb (each with purity of 99.9% or more, average particle size of several tens of microns, all 5 wt.
After adding powders of low melting point elements (vo1%), they were mixed in a ball mill. This mixed powder was heated to 600℃ under vacuum.
temperature and pressure of 1000 kg/csA for 15 minutes.
I pressed my throat.

As a comparative example, (Nd+5FetJt)qs8to5
and Nd13Fes+86, and after melting,
It was crushed and hot pressed under the same conditions as above. The results are shown in Table 1.

Table 1 (First Example of the Present Invention) The rest of the following (Conventional Example) Second Example Next, as a second example, a mixture using a matrix material powder made of a low melting point element will be described. Before hot-pressing the powder,
The case is shown in which a preform is formed by pressure molding in advance. Nb with a purity of 98% or more, purity 99.9 as a starting material for magnetic materials
Using electrolytic iron with a purity of 99.5% or more and B with a purity of 99.5% or more,
A rare earth-iron alloy ingot having a composition of Nd+, 1Fes+Bb is prepared. These are melted in a high-frequency melting furnace in an Ar atmosphere, crushed to 24 meshes or less using a crusher and a disk mill, and then subjected to a crushing process in which they are finely crushed to an average particle size of 3 microns using a ball mill. Then, 2 wt % of A1.
5wt% Sn, 5wt% Zns 2wt% 515wt% In, 4wt% Ga, 4wt
% Ge, 4 wt % Fes, 611° C. % Cu, and 7 wt % Pb (each with a purity of 99.9% or more). After adding powders of low melting point elements, the mixture is mixed using a ball mill. This mixed powder is preferably heated at 25kO
After pressure molding at a pressure of 1.5 ton/Cl11 in a magnetic field of
The sample is subjected to a hot pressing step for 15 minutes at a pressure of /cal.

In addition, as a conventional example, (Nd+5Fe2qBq)qsA
Hot pressed with ls and Nd14FEls+b.

Table 2 shows a comparison between the magnetic properties of each of the obtained molded bodies and the conventional example. In the second example, residual magnetic flux density Br, coercive force, 11c, and maximum energy product B II m a x
In particular, compared to the first example, the residual magnetic flux density Br significantly increased due to crystal orientation due to magnetic field shaping.

Table 2 (Second Example of the Present Invention) (Conventional Example) 1. Third Example - The mixing ratio when the matrix material powder is a low melting point intermetallic compound using 1 will be explained below. .

As starting materials for magnetic crystals, Nd with a purity of 98% or more, electrolytic iron with a purity of 99.9% or more, and B with a purity of 99.5% or more
An alloy having a composition of NdzPeraB was melted in a high-frequency melting furnace in an Ar atmosphere. Next, as starting materials for the matrix phase, Nd and Fe of the above purity and purity 99.
Using AI of 9% or more, Nd3oFeaoA Ex
.

An alloy having the following composition was melted in a high frequency melting furnace in an Ar atmosphere. Each of these was coarsely pulverized to 24 sieves or less using a disc mill. This powder was weighed so that the mixing ratio (volume composition ratio) of the matrix material was 0 to 15%, and pulverized with a ball mill to an average particle size of 4 microns. This mixed powder was heated at 1.5 ton/c in a 20 kOe magnetic field.
After pressure molding at a pressure of rK, 1000 to 1
Sintering was carried out in a machine at 150°C for 2 hours. Further 500~900℃
Heat treatment was performed at a temperature of 1 hour. Figure 2 shows their magnetic properties. The highest magnetic properties among these conditions,
As a comparative example, the magnetic properties of a sintered body of Nd, Fe, B are shown in Table 3.

In the margin below, the metallographic structure of this sintered body can be seen using a scanning electron microscope. Furthermore, the composition of the matrix phase and magnetic phase was analyzed using an X-ray microanalyzer.

The results are shown in Table 4.

Table 4 (at%) As a result, it was found that the magnetic properties were significantly improved by bonding the magnetic crystal particles with a matrix phase made of Nd(FeAl)s. The reason why the permanent magnetic properties gradually decrease as the Madrix phase increases from 5 to 8 vol% or more is due to the decrease in the volume composition ratio of the magnetic crystal particles.

-Fourth Example- Next, 20k
In a magnetic field of Oe, 1.5 ton/ell! After preforming by pressure molding at a pressure of 1,000 yen, hot pressing was performed under vacuum at a temperature of 800°C and a pressure of 1000 kg/cd for 15 minutes. This magnetic property is the fifth
Shown in the table.

As a result, magnetic crystal particles (Nd
It was found that the magnetic properties were the same as those described above by bonding with the FeA 1 ) matrix phase.

-Fifth Example- A case of sintering using a matrix material containing Cu will be described.

The starting material for the magnetic material is Nd annealed at 98% or higher, purity 99
Using electrolytic iron with a purity of 99.5% or more and B with a purity of 99.5% or more,
A magnetic alloy having a composition of NtlzFe+4B was melted in a high frequency melting furnace in an Ar atmosphere. This is done with a disc mill 2
It was coarsely ground to 4 meshes or less, and then finely ground to an average particle size of 3 microns using Poletex. Then, as a raw material for the matrix phase, NdCu2 powder, which has been finely ground in the same way as the magnetic alloy, is added to this magnetic fine powder at a volume composition ratio of about 10%.
After addition, the mixture was mixed using a ball mill. Add this mixed powder to 2
1.5 ton/cn in a 9kOe magnetic field! After pressure molding at a pressure of 1100-1130℃2 under vacuum
The molded body was sintered in an Ar atmosphere for an hour, and then the molded body was
Heat treatment was performed at 0 to 800°C for 1 hour in an Ar atmosphere.

Table 6 shows the highest magnetic properties among the molded bodies obtained from the above manufacturing process.

Next, the metal structure of this molded body was observed using an optical microscope (FIG. 4), and the composition of the matrix phase and magnetic phase was analyzed using an X-ray analyzer. The results are shown in Table 7.

Tables 6 and 7 show that high magnetic properties can be obtained by combining Nd, Fe, and B magnetic crystal particles with NdCu and NdFeCu compounds.

-Sixth Example- Next, a case where hot pressing is performed using a matrix material containing Cu will be described.

First, a mixed powder prepared in the same manner as in the fifth example was prepared under vacuum! Hot pressing was carried out at a temperature of 500° C. and a pressure of 1000 kg/cnl for 15 minutes. Table 8 shows the magnetic properties of the molded bodies obtained from the above manufacturing process.

According to Table 8, magnetic crystal particles are made of NdC by hot forming method.
It has been found that excellent permanent magnetic properties can be obtained by bonding with the u compound. In addition, in the fifth example and this example, NdCuz is mainly used as the matrix phase.
The compounds applied were NdCu, Nd(1:un.

Similar effects can be obtained using NdCua.

-Seventh Example- Next, a case will be described in which hot pressing is performed using a matrix material containing two types of low melting point metals, Cu and Zn. In the same manner as in the fifth example, a magnetic crystal fine powder pulverized to an average particle size of 3 microns was obtained. And to this magnetic powder,
As a matrix material (Nd2s, 4cuS2.z
After adding 10% by volume of finely ground powder having the composition Znzz, 4) to an average particle size of 3 microns, the mixture was mixed using a ball mill. This mixed powder was heated to 600 ml under vacuum.
It was pressed for 15 minutes at a temperature of .degree. C. and a pressure of 10,001 g/CTi1. Table 9 shows the magnetic properties of the molded product obtained from the above manufacturing process.

C1 Lower Margin - Eighth Example - Next, a case will be described in which sintering is performed using a matrix material containing two types of low melting point metals, Pb and Sn. As a starting material for the magnetic material, Nd with a purity of 98% or higher and a purity of 99.
Using 9% or more electrolytic iron and 99.5% or more B, N
A magnetic alloy having a composition of b2Fe14B was melted in a high frequency melting furnace in an Ar atmosphere.

Furthermore, Pb+Sn with a purity of 99.9% or more was used as the starting material for the alloy to be added. Alloys having the two types of compositions shown in Table 10 were produced using the same method as the magnetic materials.

Table 10 Alloy Composition (at%) These alloys were subjected to a molten metal powdering method (spraying method) to obtain powders of 250 mesosites or less. The magnetic material was pulverized using a ball mill to an average particle size of 3 μm. Next, these fine powders were weighed so that the volume composition ratio of the magnetic material and the additive alloy was 9515 (%), and mixed in a ball mill.

This mixed powder was heated to 1.5 ton in a 20 kOe magnetic field.
After pressure molding at a pressure of /d, 1000 to 1l under vacuum
Sintering was carried out in Ar at 50°C for 2 hours. These sintered bodies were further heat-treated at 500 to 900°C for 1 hour.

Table 11 shows numerical values for the sintered bodies that exhibited the highest magnetic properties under these conditions.

Table 11 Magnetic property values And photographs of the metal Mi weave of these sintered bodies are shown in FIG. Furthermore, compositional analysis of the matrix phase and magnetic phase was performed using an X-ray microanalyzer.

The results are shown in Table 12.

As shown in Tables 11 and 12, Nd, Fe,
It is recognized that high magnetic properties can be obtained by bonding B magnetic crystal particles with Nd (Fe, Pb, Sn).

-Ninth Example- Next, a case will be described in which a preform is formed in advance using a matrix material containing two types of low melting point metals, Pb and Sn, and then hot pressed.

A mixed powder obtained in the same manner as in the seventh example was mixed with 20
After pressure molding in a magnetic field of kOe at a pressure of 1.5 ton/cnt, this preformed body was hot pressed at a temperature of 750°C and a pressure of 1000 kg/cut for 20 minutes to obtain a molded body. After that, this molded body was heated to 600
Heat treatment was performed at a temperature of 'C for 30 minutes in an Ar atmosphere.

Table 13 shows the magnetic property values of these sintered bodies.

Table 13: Magnetic property values From this example, it is recognized that high magnetic properties can be obtained by bonding NdzFe and B magnetic crystal particles by hot forming using an Nd' (Fe, Pb, Sn) matrix material.

-Tenth Example- A case will be described in which sintering is performed using matrix materials with different mixing ratios of low melting point metals PB and Sn.

As starting materials for the magnetic material, Nd with a purity of 98% or more, electrolytic iron with a purity of 99.9% or more, and B with a purity of 99.5% or more are used, and a magnetic alloy with a composition of Nd2Fe, B is produced in an Ar atmosphere. Melted in a high frequency melting furnace.

The starting material for the alloy to be added is the above-mentioned Nd material.

Fe, Pb and Sn with a purity of 99.9% or higher were used.

These were made into alloys with the three types of compositions shown in Table 12 using the same method as the magnetic materials.

Table 14 Alloy Composition (at%) These alloys were coarsely ground to 24 meshes or less using a Shaw Crusher disc mill, and then finely ground to an average particle size of 3 μm using a ball mill. Next, these fine powders were mixed with a volume composition ratio of magnetic material and additive alloy of 9515 (
%) and mixed in a ball mill.

This mixed powder was heated to 1.5 ton in a 20 kOe magnetic field.
After pressure molding at a pressure of /-, heat treatment was performed at 500 to 900°C for 1 hour under vacuum at 1000°C to 1000°C. Table 15 shows numerical values for the sintered bodies that exhibited the highest magnetic properties under these conditions.

Table 15 The metal structure photographs of these sintered bodies are shown in FIG. Furthermore, the composition of the matrix phase and magnetic phase was analyzed using an X-ray microanalyzer.

The results are shown in Table 16.

Note that the amount of B in the matrix phase could not be quantified.

Next, these mixed powders were heated at 1.5 kOe in a magnetic field of 25 kOe.
8 ton/crl preformed body
Hot pressing was carried out for 20 minutes under the conditions of 00'C, 1, Oton/cn to obtain a molded body. After that, this molded body was
Heat treatment was performed in an Ar'W atmosphere at a temperature of 0° C. for 30 minutes. Table 17 shows the magnetic properties of these molded bodies.

Table 17 - 11th Example - 60°C for each sintered body obtained in the 3rd to 10th Examples and a sintered body having a composition of Nd, Fe, B as a comparative material A constant temperature and humidity test of ×90% was conducted for 0 to 100 hours to investigate the oxidation resistance. The results are shown in Table 18.

From Table 18, the magnet according to the present invention is similar to the conventional R-Fe-B
It can be seen that this type of magnet has superior corrosion resistance compared to other magnets.

-Twelfth Example- Each sintered compact magnet obtained in the third to tenth examples and comparison materials were Nd and 4Fe@. A sintered body having a composition of B6,
Electrolytic Ni plating, phosphate treatment, and oxidation-resistant resin coating were applied. Each coating condition is as follows: For electrolytic Ni plating, 3 to 5 μm of Cu is plated on the base, and then regular electrolytic N
I-plated. Similarly, regarding phosphate treatment,
Treated with normal phosphate solution. For epoxy resins, use a solution of epoxy resin dissolved in an organic solvent, and after spray coating, apply at a temperature of about 150°C.
An epoxy resin film was formed on the magnet surface. These test pieces were subjected to a salt spray test (JIS-Z-2371) from 0 to 48
The oxidation resistance and magnetic properties after coating were investigated. The results are shown in Tables 19 and 20.

Table 19 shows that the magnets of the present invention have excellent corrosion resistance, and the coating hardly deteriorates the magnetic properties.

-Thirteenth Example- Next, as a thirteenth example, a case will be described in which the preform is heated at the melting point temperature of the low melting point phase (100 to 800°C) and then extruded.

First, a magnetic alloy with the composition Nd++Ff3s+Bb,
It was melted in a high frequency melting furnace in an Ar atmosphere. this,
It was coarsely crushed to 24 meshes or less using a crusher and a disc mill, and then finely crushed to an average particle size of 3 microns using a ball mill. Then, Zn and Sn with a volume composition ratio of 5% are added to this magnetic powder as a matrix material.

After adding powders of low melting point elements (each with a purity of 99.9% or more), they were mixed in a ball mill. This mixed powder was molded into a preform under a pressure of 1.5 ton/c4 in a magnetic field of 25 kOe. 700 pieces of this preform
After heating to ℃, apply glass powder with high heat insulation properties. Thereafter, the preformed body is placed in a vertical extrusion molding device to form a desired molded body.

Table 21 shows a comparison between the magnetic properties of each of the molded bodies obtained through the above manufacturing process and the conventional example. As a result, even by extrusion molding, it can be densified at low temperature, so it has a larger magnetic phase content than the conventional example, and has a residual magnetic flux density Br, a coercive force Hc, and a maximum energy product BHm.
An improvement in ax was observed.

Margins below - Fourteenth Example - Next, as a fourteenth example, a case where a molded body is subjected to reheat treatment will be described.

First, a magnetic alloy having a composition of Ndl5Fea1Bb was melted in a high-frequency melting furnace in a controlled atmosphere. This was coarsely ground to 24 meshes or less using a crusher and a disc mill, and then finely ground to an average particle size of 3 microns using a ball mill. Then, Zn and Sn with a volume composition ratio of 5% are added to this magnetic powder as a matrix material.

After adding powders of low melting point elements such as Ar and Sn (each with a purity of 99.9% or more), they were mixed in a ball mill.

This mixed powder was heated to 1.5 ton in a 25 kOe magnetic field.
The preform was molded at a pressure of /ci. This preformed body was hot pressed at a temperature of 700° C. and a pressure of 1000 kg/c+d for 15 minutes to obtain a molded body. Thereafter, this molded body was subjected to reheat treatment at a temperature of 600° C. for 10 minutes in an Ar atmosphere.

Table 22 shows a comparison of the magnetic properties of the molded product subjected to such reheat treatment and the molded product before reheat treatment.

Although there is little change in the values of the residual magnetic flux density Br and the maximum energy product BHmax, a significant improvement in the coercive force Jc is observed due to the reduction in the number of sites where reversed magnetic domains occur due to the reheat treatment.

Below is a margin Here, in FIG.
14 shows the correlation between the reheat treatment temperature and the coercive force IHc when the molded body of No. 14 was reheated for 10 minutes in an Ar atmosphere at various heat treatment temperatures. The * mark in the figure indicates the coercive force and HcO value of the compact before heat treatment. The results show that the most effective reheating temperature is 300 to 900°C.

In addition, FIG. 8 shows a real breath (NdlyFeerBb) q6A j
The molded product of 2a was heated for 600' within various heat treatment times.
Heat treatment time and magnet properties (residual magnetic flux density Ar, coercive force,
The correlation with Hc) is shown. It can be seen that the highest magnetic properties are obtained when the heat treatment is performed for about 10 minutes.

In addition, in FIGS. 7 and 8, (Nd1xFes+Bb)q
6A j! Although only the heat treatment temperature and heat treatment time using No. 4 are shown, similar results could be obtained using other low melting point elements.

-Fifteenth Example- Next, a case will be described in which a matrix material made of finely powdered high-melting point metal is used.

First, a magnetic alloy with the composition of Nd+3Fe and Bb was
It was melted in a high-frequency melting furnace in an r atmosphere. This was coarsely ground to 24 meshes or less using a crusher and a disc mill, and then finely ground to an average particle size of 3 microns using a ball mill. Then, ultrafine powders made of high melting point elements of Fe, Co, and Ni (each with a purity of 99.9% or more; average particle diameter of 20 nanometers) with a volume composition ratio of 5% were added to this magnetic powder as a matrix material. , and mixed in a ball mill. Next, this mixed powder was preformed at a pressure of 1.5 ton/cat in a magnetic field of 25 kOe, and then hot pressed under vacuum at a temperature of 700°C and a pressure of 1000 kg/- for 10 minutes to obtain a molded body. Ta.

The molded body obtained as above and an average particle size of 100
Table 23 shows the magnetic properties of the compact when Al, which is a low melting point element with micron (105 nanometer) and purity of 99.9% or more, is used. As a result, Fe, Co+N
It can be seen that even when a high melting point element such as i is used, sufficient magnetic properties can be obtained at a low heating temperature of about 700°C. In addition, as shown in the lower part of Table 23, the average particle diameter is 20
Nanometer A7! From a comparison of the magnetic properties of A1 and 10' nanometer A1, it is recognized that the ultrafine powder has a larger coercive force and 11c. This indicates that regardless of whether the matrix material is for a low melting point phase or a high melting point phase, uniform dispersion of magnet crystal particles is promoted by making the matrix material into ultrafine powder.

The following margins are also shown in FIG. 9, which is hot pressed (Nd+5Fea+86) in the same manner as shown in the 15th embodiment above.
In +Fe4 alloy, the correlation between various average particle diameters of Fe, which is a matrix material, coercive force, and Hc is shown. 2
With an average particle diameter of 0 nanometers as the peak, 1,00
It is recognized that a high coercive force +Hc is exhibited down to 0 nanometer.

1.Sixteenth Example--Next, as a sixteenth example, a case will be described in which the matrix material of a low melting point element is made into ultrafine powder and the molded product is subjected to reheat treatment.

First, a magnetic alloy with the composition Nd + sf'es + Bi,
It was melted in a high-frequency melting furnace in an air atmosphere. This was coarsely ground to 24 meshes or less using a crusher and a disc mill, and then finely ground to an average particle size of 3 microns using a ball mill. Then, this magnetic powder was added as a matrix material with a volume composition ratio of 3.5% IN! (Purity 99.9
% or more; average particle diameter of 20 nanometers) of ultrafine powder of a low melting point element was added and mixed in a ball mill. This mixed powder was heated to 1.5 ton/ct in 25 kOe hot water.
Preliminary bottom molding was performed at a pressure of M.

After heating this preform to a temperature of 700℃ under vacuum, and coating it with glass powder with high heat insulation properties, it becomes 1000 kg/C.
Hot pressing was carried out at a pressure of RL. Thereafter, a reheat treatment was performed at a temperature of 600° C. for 10 minutes in a stationary atmosphere.

The magnetic properties of the obtained magnet are shown in Table 24. As a comparative example, A1 with an average particle diameter of 100 microns (purity 99.
The characteristics before and after heat treatment when using 9% or more are also shown. As a result, it was found that coercive force +Hc was improved by performing reheat treatment.

Margins below - Seventeenth Example Next, a case will be described in which a matrix material of a low melting point compound is used as a seventeenth example. As starting materials for the magnetic material, Nd with a purity of 98% or more, electrolytic iron with a purity of 99.9% or more, and B with a purity of 9915% or more are used.
e□B6, melted in a high-frequency melting furnace in an Ar atmosphere, and melted into 2
It was coarsely ground to 4 meshes or less, and then finely ground to an average particle size of 3 microns using a ball mill. Then, 4.4wt% of 8'++Zn was added to this fine powder as a matrix material.
@g, 2.4wt% An! 53 cu1y (each purity 9
8% or more, average particle size 1-10 microns, 5 vol each
%) of low melting point compound powders were added and mixed using a ball mill. This mixed powder is 1.5 ton/
Preforming was carried out in a magnetic field of 25 kOe at a pressure of ci, and the obtained molded body was molded under vacuum at a temperature of 600°C and 1000 kOe.
Hot pressed for 15 minutes at a pressure of g/ci. Table 25 shows the magnetic properties of the obtained magnet. Effects similar to those of the second example described above were observed.

-Eighteenth Example- Next, as an eighteenth example, a case will be described in which a matrix material of an ultrafine high melting point compound is used. As starting materials for the magnetic material, Nd with a purity of 98% or more, electrolytic iron with a purity of 99.9% or more, and B with a purity of 99.5% or more are used.
The composition of eetL is melted in a high frequency melting furnace in an Ar atmosphere, and then melted in a crusher and disc mill.
It was coarsely ground to 4 meshes or less, and then finely ground to an average particle size of 3 microns using a ball mill. Then, 2.8 wt% of A 1 bb was added to this fine powder as a matrix material.
Ff3z<-, 4.6wt%^l zsNi, ss
4.8 wt% of 8 l tocoso, 2.5 wt% of A j! , 5cr25 (each with a purity of 98% or more, an average particle size of 10 to 1000 nanometers (0.1 microns), each 5vo1%) of ultrafine powder of a high melting point compound, respectively.
Mixing was performed using a ball mill. This mixed powder is 1.5
It was molded in a magnetic field of 25 kOe at a pressure of ton/cd, and hot pressed for 10 minutes at a pressure of 1000 kg/ci. The magnetic properties of the obtained magnet are shown in Table 26. Effects similar to those of the previously described 15th example were observed.

References (IIK, J, 5trnat; IEEE Tran
s, Mag, (1972) 511°(2)N,
C, Koon and B, N, Das: Appl
, Phys, Lett, 39(10) (1981),
840゜(3) Kano, Yanagida, eds.: Rare earths - their physical properties and applications Gihodo Publishing, (1980), p52゜(4) N, F,
Chaban, Y.B., Kuz'ma, N.S.B.
11onizhko.

0.0. Kachmar and N., W., Petr.
ivHDopodivi Akad.

Nauk, Ukr, R.S.R., Ser, A. (1979).
Disease 10. p875-877゜(5) J, J, Croa
T., J.F., Herbst, R.W. and
F.E.

Pinkerton; J, Appl, Phys, 55
(1984) 2078° (6) JP 60-9852 (7) Ro, Mishra: J, Magneti
sm and MagneticMaterials
54-57 (1986) 450° (8) JP-A-59-
46008 (9) Kaneko, Zeroma: Magnetic materials, Japan Institute of Metals (1977
).

194゜ [Effects of the Invention] As described above, according to the present invention, the matrix material, RAT, and 4B-based exogenous crystallites are mixed and densified while controlling the interdiffusion reaction between the two at low temperatures. can be realized.

Therefore, (1) the magnetic crystal particles are stoichiometrically weighed R2T
Since the magnetic crystal particles are formed directly from the 14B magnetic powder and the matrix phase acts as a binding phase at a lower temperature, the magnetic crystal particles can maintain a composite composition without changing their crystal structure.

(2) By using elements with excellent corrosion resistance in the compositional components constituting the matrix phase, it is possible to form a compound phase with excellent corrosion resistance, and therefore, excellent corrosion resistance can be obtained.

(3) Hot forming method (extrusion, rolling, Hot Press
, tlIP, etc.), the dimensional yield of the product can be improved. ;==Crack 4; (4) A low melting point phase powder with a low melting point is mixed with magnetic crystal particles as a matrix material, and the powder is heated to the conventional sintering temperature (900~900℃).
By hot pressing at a temperature lower than 1200°C (300 to 1100°C), the surface of the particles is covered with a smooth elemental interface of the matrix material, and by wetting it, the coercive force Hc of the magnet material is increased. can be improved.

(5) By subjecting the molded body to reheat treatment at a temperature of substantially 300 to 900°C, diffusion reactions with magnetic crystal particles can be suppressed and the occurrence of reversed magnetic domain generation sites can be reduced. A high coercive force 11c can be obtained.

(6) Pressure molding of a mixed powder of matrix material powder and pulverized magnetic powder allows the magnetic powder to be plastically deformed, thereby promoting densification and further improving the residual magnetic flux density Br. can.

(7) Fluidity of the matrix material with a substantially low melting point;
By utilizing plastic deformation of the magnetic phase due to pressure,
Since it is possible to reduce the volume of the matrix material during hot pressurization (more than 1% in volume composition ratio), the interdiffusion reaction between the matrix material and the magnetic crystal particles can be suppressed by heating at a low temperature for a short time. At the same time, the residual magnetic flux density B
It is also possible to increase r.

(8) In addition to magnetically blending the mixed powder of matrix material and magnetic powder during pressure molding of the preform in a magnetic field, it is possible to
The magnetic orientation of the compact can also be further improved.

(9) In addition, by heating the preform at the melting point temperature of the low melting point phase in advance and then extruding it, the preform can be melted and extruded while suppressing the mutual diffusion reaction between the matrix material and the magnetic powder. Therefore, it is possible to obtain a molded article in the final shape with high magnetic properties without reducing the magnetic content.

αω The high melting phaseless matrix material has an average particle diameter of 20
By making ultrafine powder of ~1,000 nanometers,
Since it can promote mass transport in a high melting phaseless phase while maintaining its excellent corrosion resistance, it can be handled in the same way as a low melting point phase. Further, by making the powder into ultrafine powder regardless of whether it is a high melting phaseless phase or a low melting point phase, it is possible to improve the uniform dispersibility of the matrix material with respect to the magnet crystal particles.

[Brief explanation of the drawing]

Figure 1 is a composite structure diagram of rare earth-iron magnet material. Figure 2 is NdtFe+ aBHdxoPeaoA 1 z. The relationship between volume composition ratio and magnetic properties is shown. Figure 3 shows (NdzFe+ 48) qs(NdsoFe
a. A130) This is a photograph of the structure of S sintered alloy. Figure 4 shows (NdJe+ 4B) 119. +S (N
dCuz) + o, s A photograph of the structure of the sintered body. Figure 5 shows (NdzFe+ <8) 95 (Pbbq,
6snzo, 4) This is a photograph of the Mi weave of the 5 sintered body. Figure 6 shows (NdzFe+ 4B) 95 CNdaoF
This is a photograph of the Mi weave of the e4oPbzoSnzo)s sintered body. Figure 7 shows the matrix material using AI! It is a graph showing the correlation between the reheat treatment temperature, coercive force, and 11C of a molded article when it is closed. FIG. 8 is a graph showing the correlation between the reheating time of the molded body and the coercive force, 11c, when the matrix material is An. FIG. 9 is a graph showing the correlation between the average particle diameter of the matrix material and the coercive force IHc when the high-melting phaseless matrix material is Fe. Figure 10 shows the Nd-Fe-B ternary phase diagram (4) (Pa,
sJo, Is) o, Jo, + (R: Tb
o, osLao, os). Figure 1 Figure 2 Volume composition ratio of Nd3o Fe40A7xo (mu) Figure 7 Figure 8 Figure 9 Average particle diameter (nanometer) Figure 1o Fe

Claims (1)

[Claims] 1) In terms of volumetric ratio, 0 to 10% (excluding 0) of the matrix phase, and the remainder composed of R_2T_1_4B magnetic crystal particles (where R is Y and a rare earth element, and T is representing a transition metal), and the interface of the magnetic crystal grains is covered with the matrix phase.
T_1_4B composite magnet material. 2) In the R_2T_1_4B composite magnet material according to claim 1, the matrix phase is Al
, Zn, Sn, Cu, Pb, S, In, Ga, Ge, T
An R_2T_1_4B-based composite magnet material characterized by having a low melting point phase containing at least one low melting point element selected from e. 3) In the R_2T_1_4B composite magnet material according to claim 2, the low melting point phase includes an intermetallic compound, and the intermetallic compound includes at least one element selected from R, T, and B. and Al, Zn, Sn, Cu,
An R_2T_1_4B-based composite magnet material, which is an intermetallic compound comprising at least one low-melting point element selected from Pb, S, In, Ga, Ge, and Te. 4) In the R_2T_1_4B composite magnet material according to claim 1, the matrix phase is Fe.
, Co, Ni, and Cr.
T_1_4B composite magnet material. 5) In the R_2T_1_4B composite magnet material according to claim 4, the high melting point phase includes R, T, and B.
at least one element selected from Fe, Co,
R_2 characterized by containing an intermetallic compound consisting of at least one high melting point element selected from Ni and Cr
T_1_4B composite magnet material. 6) A pulverizing step of pulverizing an ingot made of R_2T_1_4B magnetic crystals (where R represents Y and a rare earth element, and T represents a transition metal) to form an R_2T_1_4B magnetic powder, and a pulverization process in which a volume composition ratio of 0 to 10 % (not including 0)
The matrix material powder and the remainder constitute the R_2T_
1. A method for manufacturing an R_2T_1_4B composite magnet material, comprising a mixing step of mixing the mixed powder with a R_2T_1_4B magnetic powder to form a mixed powder, and a magnetizing step of molding and magnetizing the mixed powder. 7) In the method for manufacturing an R_2T_1_4B composite magnet material according to claim 6, the mixing step includes:
A method for producing an R_2T_1_4B composite magnet material, comprising the step of ultrafinely pulverizing the matrix material powder to a particle size substantially in the range of 20 to 1000 nanometers. 8) R_2T_ described in claim 6 or 7
In the method for manufacturing a 1_4B composite magnet material, the matrix material powder includes Al, Zn, Sn, Cu, Pb,
R_2T_1 characterized by containing at least one low melting point element selected from S, In, Ga, Ge, and Te
_4B-based composite magnet material manufacturing method. 9) R_2T_ described in claim 6 or 7
In the method for manufacturing a 1_4B-based composite magnet material, the matrix material powder contains at least one element selected from R, T, and B, and Al, Zn, Sn, Cu, Pb, and S.
, In, Ga, Ge, and Te, and at least one low-melting point element selected from the group consisting of an intermetallic compound. 10) R_2T described in claim 6 or 7
A method for producing a R_2T_1_4B composite magnet material, wherein the matrix material powder contains at least one high melting point element selected from Fe, Co, Ni, and Cr. . 11) R_2T described in claim 6 or 7
In the _1_4B-based composite magnet material, the matrix material powder is a metal consisting of at least one element selected from R, T, and B and at least one high-melting point element selected from Fe, Co, Ni, and Cr. 1. A method for producing an R_2T_1_4B-based composite magnet material, characterized by containing an intermediate compound. 12) R_2T_ described in claims 6 to 9
In the method for manufacturing a 1_4B-based composite magnet material, the magnetizing step includes a sintering step of forming the mixed powder in a magnetic field and then sintering it to produce a sintered body.
_1_Method for manufacturing 4B-based composite magnet material. 13) R_2T_1_4 described in claim 12
A method for manufacturing a B-based composite magnet material, wherein the sintering step includes a reheat treatment step of further subjecting the sintered body to a reheat treatment. 14) R_2T described in claims 6 to 11
_1_2 In the method for producing a 4B-based composite magnet material, the magnetizing step includes a hot pressing step of hot pressing the mixed powder to produce a compact.R_2
A method for manufacturing a T_1_4B-based composite magnet material. 15) R_2T_1_4 described in claim 14
In the method for manufacturing a B-based composite magnet material, the hot pressing temperature in the hot pressing step is substantially 300 to 11
R_2T_1_ characterized by being within the range of 00°C
A method for manufacturing a 4B-based composite magnet material. 16) R_2 described in claim 14 or 15
In the method for manufacturing a T_1_4B-based composite magnet material, the hot pressing pressure in the hot pressing step is substantially 5
A method for producing an R_2T_1_4B composite magnet material, characterized in that the magnetic flux is within the range of ~5000 kg/cm^2. 17) In the method for manufacturing an R_2T_1_4B composite magnet material according to any one of claims 14 to 16, the hot pressing step includes press-molding the mixed powder in advance as a pretreatment step. A method for producing an R_2T_1_4B composite magnet material, the method comprising a preforming step of preparing a preform. 18) R_2T_1_4 described in claim 17
A method for producing an R_2T_1_4B composite magnet material, wherein in the hot pressing step, the preform is formed into a molded body by extrusion molding. 19) R_2T_1_4 described in claim 18
In the method for producing a B-based composite magnet material, the hot pressing step includes a step of applying a heat insulating material to the preform before extrusion molding. R_2T_1
_4B-based composite magnet material manufacturing method. 20) In the method for manufacturing an R_2T_1_4B composite magnet material according to any one of claims 14 to 19, the hot pressing step includes heat-treating the molded body again as a post-treatment step. A method for producing an R_2T_1_4B composite magnet material, the method comprising a reheat treatment step. 21) R_2T_1_4 described in claim 20
In the method for manufacturing a B-based composite magnet material, the reheating temperature in the reheating step is substantially 300 to 90°C.
R_2T_1_4 characterized by being within the range of 0°C
A method for manufacturing a B-based composite magnet material.