JPH061726B2 - Method of manufacturing permanent magnet material - Google Patents

Description

The present invention relates to a method for producing a FeCoBRM based permanent magnet material which is based on FeBR and contains an additional element M and in which a part of Fe is replaced by Co.

Permanent magnet materials are one of the extremely important electric and electronic materials used in a wide range of fields from various household electric appliances to peripheral terminals for large computers. In recent years, with the demand for miniaturization and high efficiency of electric devices, permanent magnet materials are required to have higher performance. Further, practically, there are many applications such as motors, generators, electric couplings, etc. which require extremely large reverse magnetic fields, and there is also a demand for magnetic materials having high coercive force.

Typical permanent magnets currently in use are alnico, hard ferrite, and rare earth cobalt magnets. However, due to the recent destabilization of the raw material situation of cobalt, the demand for alnico magnets containing 20 to 30% by weight of cobalt has decreased, and inexpensive hard ferrite containing iron oxide as the main component seems to be the mainstream of magnet materials. Became. On the other hand, the rare earth cobalt magnet is very expensive because it contains 50 to 65% by weight of cobalt and Sm which is not contained in rare earth ore is very expensive. It is often used in magnetic circuits with high added value.

In order for rare earth magnets to be used in large quantities at low cost in a wider field, it is necessary not to contain expensive cobalt and to use light rare earths, which are contained in ores in large amounts as rare earth metals, as the main component. is necessary. As one attempt for such a permanent magnet material, an RFe ₂ compound (where R is at least one rare earth element) has been proposed. Amorphous TbFe ₂ obtained by sputtering has an energy product of 29.5 MGOe at 4.2 ° K, and when this is heat-treated at 300 to 500 ° C., coercive force is 3 at room temperature. It has been found that the maximum energy product is 0.7 MGOe. A similar study is S
Also carried out for mFe ₂ , 9.2 MGOe at 77 ° K.
It has been reported that However, all of these are thin films made by sputtering, and are not magnets that can be used for general speakers and motors. In addition, a ribbon produced by super-quenching a PrFe alloy is 2.8.
It has been reported to exhibit a high coercive force of kOe. Furthermore, Kuhn and others have (Fe · B) _0.9 Tb _0.05 La
Amorphous ribbon obtained by ultra-quenching of _0.05
It was found that the coercive force reaches 9 kOe when annealed at ℃ (Br is 5 kG). However, in this case, the maximum energy product is low due to the poor squareness of the magnetization curve (NC Ko
on et al. Appl. Phys. Lett. 39 (10),
1981, 840-842).

Also, L. Kabacoff etc. is (FeB)
_It has been reported that some ribbons having a composition of _1-χ Pr _χ (x = 0 to 0.3 atomic ratio) and prepared by ultra-quenching have a coercive force of kOe level at room temperature in a Fe / Pr binary system. There is.

The ribbon or thin film formed by sputtering in the ultra-quenching is not a practical permanent magnet (body) that can be used as such, and a practical permanent magnet cannot be permanently obtained from these ribbons and thin films. That is, Fe / B that has been provided conventionally
・ Arbitrary shape from R type ribbon or RFe type thin film
It is not possible to obtain bulk permanent magnet bodies with dimensions.
Further, the magnetization curves of the FeBR ribbons reported so far are not good in shape and are not regarded as practical permanent magnet materials capable of competing with conventionally used magnets. Furthermore, the ribbons obtained by ultra-quenching and the thin films formed by sputtering are essentially isotropic, and it is virtually impossible to obtain a practical permanent magnet having magnetic anisotropy from them.

Therefore, the object of the present invention is to eliminate the above-mentioned disadvantages of the conventional method C
It is not necessary to include a large amount of rare substances such as o.
FeBR that does not necessarily need to use rare rare earths such as
The basic purpose is to obtain a new permanent magnet material based on the system. Furthermore, it has good magnetic properties at room temperature and can be formed into any shape and practical size. It is intended to provide a method for producing a substance which can effectively use abundant light rare earth elements.

The present inventors previously invented a FeBR-based permanent magnet material that does not necessarily use Sm and Co (Japanese Patent Application No. 57-1).
45072). This FeBR permanent magnet material is based on a new compound different from the conventionally known RCo ₅ and R ₂ Co ₁₇ compounds, and in particular, boron (B) is
For example, it is not added as an amorphous accelerating element at the time of producing an amorphous alloy or a sintering accelerating element in the powder jig method, but is a magnetically stable and high magnetic substance that constitutes the substance of this FeBR permanent magnet material. R-Fe- having an anisotropic constant
Clarified that it is an essential constituent element of B compound (It was also clarified that a magnetic anisotropic sintered permanent magnet can be obtained by forming an appropriate microstructure based on the above FeBR permanent magnet material) . Furthermore, such FeB
The R-based permanent magnet material has an average particle size of 0.
It can be produced by molding an alloy powder (composition) having a particle size of 3 to 80 μm and sintering it at 900 to 1200 ° C. in a non-oxidizing atmosphere. The inventors have also invented that the magnetic characteristics can be improved, and filed a separate application (Japanese Patent Application Nos. 58-88372 and 58-90801).

In order to achieve the above-mentioned object, the inventors of the present invention have further earnestly studied a method for producing a crystalline FeBR-based permanent magnet material based on such a ternary compound, and as a result, based on Fe.BR. With the additional element M (V,
Nb, Ta, Mo, W, Cr, Al, Ti, Zr, H
f, Mn, Ni, Ge, Sn, Bi, Sb, Si, Z
n.) including F. Co. In the manufacturing method in which alloy powders of B, RM, and M composition within a certain composition range are molded, sintered, and further heat treated, the two-stage heat treatment under specific conditions for the heat treatment process is performed to obtain magnet characteristics, particularly coercive force and squareness. The present invention has been accomplished by finding that a permanent magnet material having an extremely high value can be obtained.

That is, according to the present invention, R in atomic percentage is 8 to 30% (provided that R is at least one kind of rare earth element including Y), B in 2 to 28%, and predetermined%.
1 or 2 or more of the following additive elements M (excluding M 0%, M is V 9.5% or less, Nb 12.5% or less, Ta 10.5% or less, Mo 9.5% or less, W 9.5% or less, Cr 8.5% Below, Al 9.5% or less, Ti 4.5% or less, Zr 5.5% or less, Hf 5.5% or less, Mn 8.0% or less, Ni 8.0% or less, Ge 7.0% or less, Sn 3.5% or less, Bi 5.0% or less, Sb 2.5% Hereinafter, Si 5.0% or less and Zn 2.0% or less, and when two or more kinds of M are included, the total amount of M is less than or equal to a predetermined% of the M elements having the maximum value), and the balance Fe and the production. FeBR composed of inevitable impurities
An alloy powder having an FeCoBRM composition in which a part of Fe in the M composition is replaced with 50% or less of Co (excluding 0%) with respect to the total composition, and having an average particle size of 0.3 to 80 μm. Forming step, step of sintering at 900 to 1200 ° C. in a reducing or non-oxidizing atmosphere, 750 to 1 after sintering
After the first heat treatment for 0.5 hours or more at a temperature of 000 ° C, 10 ° C /
75 at a cooling rate of over 2000 min / 2000 ° C / min
The temperature range of 0 to 700 ° C is cooled, and further 480 to 70
The above object is achieved by a method for producing a permanent magnet material, which comprises a step of performing a secondary heat treatment at a temperature of 0 ° C. Given 2
By the step heat treatment, it is possible to further improve the coercive force and the squareness of the demagnetization curve not only for the sintered body of the same composition that has not been heat-treated but also for the one that has been subjected to the one-step heat treatment. To be In this respect, for example, when the coercive force is increased by increasing the rare earth element R, the residual magnetic flux density is decreased (see Japanese Patent Application No. 57-145072), which is extremely significant. The obtained permanent magnet material exhibits particularly excellent magnetic properties in the FeCoBRM composition when anisotropic.

The present invention is characterized in that a permanent magnet body having magnetic anisotropy is obtained, unlike conventional FeBR-based amorphous ribbons, but isotropic ones are superior to conventional isotropic permanent magnets. You can get what you want. Hereinafter, the description will be given mainly on the basis of the case of anisotropy.

Fe. In the Co, B, R, M permanent magnet material, B is 2% or more (the following% indicates the atomic percentage in the alloy) in order to satisfy the coercive force of 3 kOe or more, and the residual magnetic flux density Br of hard ferrite is about 6 kG or more. In order to achieve this, R is set to 30% or less, and R is required to be 8% in order to set the coercive force to 3 kOe or more.

As B (boron), pure boron or ferroboron can be used, and those containing Al, Si, C or the like as impurities can also be used.

As R, a light rare earth which is abundant in terms of resources can be used and does not necessarily require Sm or mainly Sm, so that the raw material is inexpensive and extremely useful. The rare earth element R used in the permanent magnet of the present invention includes Y and is a rare earth element including light rare earth and heavy rare earth, and at least one of them is used. That is, R is Nd, P
r, La, Ce, Tb, Dy, Ho, Er, Eu, S
m, Gd, Pm, Tm, Yb, Lu, Y are included.
As R, Nd and Pr are particularly preferable. Usually, one of Nd, Pr, Dy, Tb, Ho, etc. is sufficient as R, but in practice, a mixture of two or more (Misch metal,
Zijim, etc.) can be used for reasons of availability. Sm, Y, La, Ce, Gd, etc. are other R, especially N
It can be used as a mixture of d, Pr, Dy, Tb, Ho and the like. It is preferable that Sm is not included or as small as possible, and it is not preferable that La is also included in large amount. Therefore S
Each of m and La is preferably 2% or less (more preferably 1% or less). It should be noted that R does not have to be a pure rare earth element and may be one containing impurities (other rare earth elements, Ca, Mg, Fe, Ti, C, O, etc.) that are unavoidable in manufacturing within the industrially available range. I can. In addition, as R,
R ₁ is Dy, Tb, Gd, Ho, Er, Tm, Yb
One or more, and a combination of one or more rare earth elements including Y other than R ₁ and the total of 80% or more of Nd and Pr as R ₂ is most preferable for the effect of increasing iHc.

The permanent magnet material obtained by the present invention improves the temperature characteristics of the magnet material by partially substituting Fe for Co in the FeBR magnet material. A light rare earth element such as Pr is used to exhibit high magnetic properties.

In general, the addition of Co to the Fe alloy includes an increase in the Curie point Tc and a decrease in the Curie point Tc due to an increase in the addition amount, and it is generally difficult to predict the effect of addition. In the present invention, as a result of replacing Fe with Co, it has been clarified that Tc gradually increases as the amount of Co replacement increases.
A similar tendency is confirmed regardless of the type of R in the magnet material composition. Even a small amount of Co substitution (for example, 0.1% to 1% with respect to the total composition) is effective in increasing Tc, and an alloy having an arbitrary Tc of about 310 to about 750 ° C. is obtained depending on the amount of Co substitution. However, if the Co content is 50% (hereinafter,% represents the atomic percentage in the alloy) or less, a sufficient effect can be obtained.

In the permanent magnet material obtained by the present invention, the additional element M
Has an effect of increasing the coercive force, and particularly, the coercive force is remarkably increased in the maximum Br region to improve the squareness. Increasing the coercive force increases the stability of the magnet and expands its application. However, Br decreases as the amount of M added increases, and therefore the maximum energy product (BH) max
Is reduced. Although the use of high coercive force iHc is required recently even if (BH) max is a little low, alloys containing M are very useful, though (BH) ma is very useful.
x is particularly useful in the range of 6 MGOe or more.

In order to clarify the effect of each addition element M on Br, the change of Br is measured by changing the amount of addition, and the range of hard ferrite Br of about 4 kG is taken into consideration. (BH) max Considering a range much higher than about 4 MGOe, the upper limit of the amount of M added is V 9.5% or less, Nb 12.5% or less, Ta 10.5% or less, Mo 9.5% or less, W 9.5% or less, Cr 8.5% or less. , Al 9.5% or less, Ti 4.5% or less, Zr 5.5% or less, Hf 5.5% or less, Mn 8.0% or less, Ni 8.0% or less, Ge 7.0% or less, Sn 3.5% or less, Bi 5.0% or less, Sb 2.5% or less , Si 5.0% or less, and Zn 2.0% or less M does not contain 0%, and one or more kinds can be added. When M is contained in two or more kinds, it generally indicates an intermediate value of the characteristics of each additive element, and the content of each element is within the above range, and the total content is the above% for each element.
Is less than or equal to the maximum value of.

In the FeBRM composition of the permanent magnet material obtained by the present invention, the maximum energy product (BH) max is much higher than that of the hard ferrite magnet (~ 4MGOe).

Further, it contains 50% or more of light rare earth elements (Nd, Pr) in the total R, and contains 12 to 24% R, 3 to 27% B and Co.
50% or less, additional element M is V8.0% or less, Nb10.5% or less, Ta9.5% or less, Mo7.5% or less, W7.5% or less, C
r6.5% or less, Al7.5% or less, Ti4.0% or less, Zr4.5
% Or less, Hf4.5 or less, Mn6.0% or less, Ni3.5% or less, Ge5.5% or less, Sn2.5% or less, Bi4.0% or less,
Sb1.5% or less, Si4.5% or less, and Zn1.5% or less, and 1 or 2 or more kinds, and the total amount of M is the atomic percentage of the element having the maximum value among the elements of M contained. Less than,
When the balance is substantially in the Fe composition range, (BH) max
Is a preferable range of 10 MGOe or more. As an even more preferable range, (Nd + Pr) is contained in an amount of 50% or more of the total R, and 12 to 20% R, 4 to 24% B, and Co2.
5% or less, additional element M is V6.5% or less, Nb 8.5% or less,
Ta8.5% or less, Mo5.5 or less, W5.5 or less, Cr4.5% or less, Al5.5% or less, Ti3.5% or less, Zr3.5% or less,
Hf3.5% or less, Mn4.0% or less, Ni2.0% or less, Ge
4.0% or less, Sn 1.0% or less, Bi 3.0% or less, Sb 0.5%
Below, Si 4.0% or less, and Zn 1.0 or less 1 type or 2
When the content is M or more and the content of M is equal to or less than the atomic percentage of the element having the maximum value among the respective elements of M contained, and the balance is substantially in the composition range of Fe, (BH) max is 15 MGO.
e or more is possible, and the maximum maximum energy product is 35
Reach MGOe.

Co is 5% or more and the temperature coefficient (α) of Br is 0.1% / ° C.
It is below, the temperature characteristic is good, and at 25% or less, it contributes to the increase of Tc without substantially impairing other magnetic characteristics (at 23% or less, it is equal or higher). As the FeCoBR base composition, R ₁ 0.05 to 5%, R _12, 5 to 20, B 4
In the case of ˜20%, Co 35% or less, and the balance Fe, the maximum energy product (BH) max of 20 MGOe or more is maintained and iHc of 10 kOe or more is realized, but the effect of the aging treatment of the present invention is further added. Furthermore, R ₁ 0.2 to 3
%, R13-19%, B5-11%, Co23% or less,
The composition of the balance Fe is the maximum energy product (BH) max30
Indicates MGOe or higher.

A more preferable range is shown below (however, M is 0.1 to 3%, preferably 1% or less, and quantitatively substitutes for Fe). As far as R is concerned, Nd +
The sum of Pr is 50% or more in all R (preferably 80% or more)
It is preferable to have high magnetic properties reliably and at low cost. 12.5-5-20% R, 5-15%
B, 65 to 82.5% Fe (Co 35% to the total composition
In the following, (substituting Fe) indicates (BH) max20MGOe or more. Here, when R> 20% and Fe <65%, Br decreases, and when Fe> 82.5%, iHc tends to decrease. 13-18% R, 5-15% B, 67-82% Fe
When (Fe is replaced by Co of 23% or less with respect to the total composition), (BH) mx25MGOe or more, where 5-11
% B is 30 MGOe or more. 6-11% B, 13
˜16% R, Co 15% or less, M2% or less, balance Fe (BH) max 35 MGOe or more, further 6.5 to 7% B, 13.5 to 14% R, Co 10% or less, M1% or less, balance In case of Fe (BH) max 40M
More than GOe, reaching up to 44MGOe.

The permanent magnet material obtained by the present invention is obtained by pulverizing, molding, sintering, and further heat treating the above composition alloy. This alloy has a ferromagnetic phase having a FeBR ternary tetragonal structure as a main phase, and a non-magnetic phase (mainly an R-rich phase) surrounds the main phase crystal. The tetragonal crystal has a central composition R ₂ Fe ₁₄ B.
The a-axis is about 8.8Å and the c-axis is about 12.2Å.
(It is considered that the addition of M within the specified amount does not cause a fundamental change in the tetragonal structure.) The nonmagnetic phase is small and 1 vol% is already sufficiently effective.

The average crystal grain size after sintering and after aging treatment is 1 to 80 μm, iHc1 kOe or more, and preferably 2 to 40 μm. The Curie temperature Tc of the FeBR ternary alloy is Ce
From 160 ° C to Tb370 ° C, usually 300 ° C or higher (P
r, Nd, Dy, Ho, etc.), but the addition of Co increases Tc as described.

The Fe / Co / B / R / M type magnet body obtained by the present invention has not only better temperature characteristics than the Fe / B / R type magnet containing no Co but also the squareness of the demagnetization curve due to the addition of Co. The maximum energy can be improved because the energy consumption is improved. Furthermore, Co has corrosion resistance compared to Fe, so Co
The corrosion resistance can be imparted by the addition of.

As M, V, Nb, Ta, Mo, W, Cr, and A
1 is particularly useful, and the effect of M is 0.1% or more and 3% or more.
The following are preferred.

The permanent magnet material obtained by the present invention is obtained by the above-mentioned specific manufacturing method.

The permanent magnet composed of the FeCoBRM-based permanent magnet body obtained by the present invention can allow the presence of impurities such as Fe, C, B, R, and M, which are unavoidable in the external industrial production.

Further, the permanent magnet material obtained according to the present invention can contain a small amount of Cu, C, S, P, Ca, Mg, O, etc. within a predetermined range, which enables improvement in productivity and cost reduction. .
Cu, P, Ca, Mg and the like may be mixed from inexpensive raw materials, C from an organic molding aid, and S and O from the manufacturing process.

According to the manufacturing method of the present invention, the alloy powder having the composition of Fe, Co, B, RM, and M having an average particle size of 0.3 to 80 μm is press-molded, and then, in a reducing or non-oxidizing atmosphere (vacuum or an inert gas atmosphere). Sintering is performed at a temperature of 900 to 1200 ° C. in the middle), and a temperature of 750 to 1000 ° C. is 0.5 hours or more after the primary heat treatment after sintering and exceeds 10 ° C./min to 2000 ° C./mi.
It is characterized in that the temperature range of 750 to 700 ° C. is cooled at a cooling rate of n or less, and the secondary heat treatment is further performed at a temperature of 480 to 700 ° C.

Hereinafter, the production method of the present invention will be described in the case of producing by dissolving a magnetic anisotropic permanent magnet material.

First, an alloy powder having the above-mentioned Fe / Co / B / R / M composition is obtained as a starting material. This may be provided by crushing an alloy ingot obtained by usual alloy melting and casting and classifying, compounding, or the like, or may be obtained from an oxide by a reducing method using a reducing agent such as Ca. A Co, B, R, M alloy powder having an average particle size of 0.3 to 80 μm is used. Average particle size 8
If the average particle size is less than 0.3 μm, excellent magnet characteristics cannot be obtained. If the average particle size is less than 0.3 μm, oxidation of the powder becomes remarkable during the pulverization or in the subsequent manufacturing process, and the density after sintering does not increase and the obtained magnet is obtained. The characteristics are also low. Average particle size 40 ~
In the range of 80 μm, the coercive force is a little low among the magnet characteristics.
In order to obtain excellent magnet characteristics, the average particle size of the alloy powder is preferably 1 to 40 μm, most preferably 2.0 to 20 μm.

The crushing is preferably performed by a wet method, an alcohol solvent,
Hexane, trichloroethane, trichloroethylene, xylene, toluene, a fluorine-based solvent, a paraffin-based solvent and the like can be used.

Next, the alloy powder is molded. The molding can be carried out in the same manner as in the conventional powder metallurgy method, and pressure molding is preferable, and in order to obtain anisotropy, pressing is performed in a magnetic field. For example, the alloy powder is 0.5 to 3.0 ton / cm in a magnetic field of 5 kOe or more.
^A molded body is formed by applying a pressure of ² . This magnetic field pressure molding is a method of molding powder as it is, acetone,
Any method of molding in an organic solvent such as toluene is possible.

Next, this compact is sintered at a predetermined temperature (900 to 1200 ° C.) in a reducing or non-oxidizing atmosphere. For example, this molded body is placed in a vacuum of 10 ⁻² Torr or less, or 1 to
Sintering is carried out at a temperature range of 900 to 1200 ° C. for 0.5 to 4 hours in an atmosphere of an inert gas or a reducing gas of 760 Torr and a purity of 99.9% or more (preferably in an inert gas). Below a sintering temperature of 900 ° C., a sufficient sintered density cannot be obtained, and a high residual bundle density cannot be obtained. Again 1200
Above ℃, the sintered body deforms and the orientation of the crystal grains collapses, resulting in a decrease in the residual magnetic flux density and a decrease in the squareness of the demagnetization curve.
Further, the sintering time may be 5 minutes or more, but if it is too long, there is a problem in mass productivity. Therefore, considering the manifestation of the magnet characteristics, the sintering time of 0.5 to 4 hours is preferable.

In the sintering atmosphere, since R, which is a component in the present alloy, is easily oxidized at a high temperature, the sintering is performed in a high vacuum or an inert gas or reducing gas atmosphere which is a non-oxidizing atmosphere. The higher the purity of the characteristic gas, the better. When using an inert gas, 1 to 760 is used as a method for obtaining a high sintered density.
It is also possible to perform in a reduced pressure atmosphere of less than Torr.

The temperature rising rate during sintering is not particularly specified, but in the case of the wet pressing method, the temperature is raised at a temperature rising rate of 40 ° C./min or less in order to remove the solvent of the organic solvent, or 200 to It is desirable to remove the solvent by keeping it in the temperature range of 800 ° C. for 0.5 hour or more.

After sintering, it is preferable that the cooling rate to room temperature is 20 ° C./min or more in order to reduce the product variation, and the cooling rate is 1 in order to continuously improve the magnet characteristics by aging treatment.
00 ° C./min or more is desirable (however, the heat treatment step can be immediately started after the sintering).

The heat treatment after sintering consists of the following steps. First, the sintered body is 7
After the first stage heat treatment at a temperature of 50 to 1000 ° C. for 0.5 hour or more, after cooling the temperature range of 750 to 700 ° C. at a cooling temperature of more than 10 ° C./min and 2000 ° C./min or less, 480 to 700 ° C. It consists of performing a second stage heat treatment at a temperature of ° C.

If the first-stage heat treatment temperature is lower than 750 ° C., the first-stage heat treatment will not be effective, and the resulting increase in coercive force will be low.
If the temperature exceeds 000 ° C., the crystal of the sintered body undergoes grain growth and the coercive force decreases.

In order to improve the coercive force of the magnet characteristics and the squareness of the demagnetization curve and reduce the variations, the heat treatment temperature of the first step should be 77
0-950 degreeC is desirable, and also 790-920 degreeC is the most preferable.

The cooling rate after the first-stage heat treatment was 10 ° C / mi.
Below n, the coercive force and the squareness of the demagnetization curve decrease, and
If it exceeds 000 ° C./min, micro cracks will occur in the sintered body and the coercive force will decrease. The temperature range in which this predetermined cooling rate should be maintained is preferably within the range from the first heat treatment temperature to 680 ° C. or lower. Both cooling and quenching are possible at a cooling rate of 680 ° C. or less. If the lower limit of the cooling temperature range at the predetermined cooling rate exceeds 680 ° C., the coercive force tends to decrease. In order to reduce the variation without deteriorating the magnet characteristics, the lower limit value of the cooling temperature range at the predetermined speed is 65
0 ° C or lower is desirable. In order to enhance the squareness of the coercive force and demagnetization curve, reduce variations in magnet characteristics, and reduce microcracks, the cooling rate is preferably more than 10 ° C / min and 1500 ° C / min or less, more preferably 20 to 10
00 ° C / min is the most desirable.

One of the features of this two-step heat treatment is preferably 68 after the first heat treatment at a temperature of 750 to 1000 ° C. for 0.5 hours or more.
After cooling to 0 ° C or below and passing between 750 ° C and 700 ° C at a predetermined cooling rate, a further low temperature range of 480
To perform secondary treatment in the temperature range of ~ 700 ° C,
When the secondary heat treatment is performed as it is by cooling the furnace after cooling it after performing the primary heat treatment, the increase in the magnet characteristics obtained is small. That is, it is presumed that some crystal structure or a metallic phase unstable region that deteriorates the magnet characteristics exists between 750 and 700 ° C., and it is considered that the influence is cut off by controlling the cooling rate.

Note that the secondary heat treatment can be performed subsequent to the predetermined cooling of the primary heat treatment, but can also be performed after the predetermined cooling and after standing.

The heat treatment temperature of the second step is limited to 480 to 700 ° C. Four
If it is less than 80 ° C. or more than 700 ° C., the improvement of the coercive force and the squareness of the demagnetization curve is reduced. In order to enhance the squareness of the coercive force and demagnetization curve and reduce the variation in magnet characteristics, the temperature range of the second heat treatment is 520 to 670 ° C.
Is preferable, and 550 to 650 is most preferable.

It is difficult to control the temperature of the first heat treatment for a short time,
Since the industrial merit decreases for a long time, 0.5-8.
0 hr is desirable.

The heat treatment time for the second step is not particularly limited, but similarly, it is difficult to control the temperature for a short time, and the industrial merit decreases for a long time, so 0.5 to 12.0 hr is desirable.

Since the atmosphere of aging treatment is R in the alloy set component rapidly react with oxygen or moisture at high temperatures in the case of vacuum vacuum degree of 10 ^-3
In the case of an atmosphere of Torr or less, an inert gas, or a reducing gas, the purity of the atmosphere is preferably 99.99% or more. The sintering temperature is selected within the above range depending on the composition of the permanent magnet material, and the aging treatment temperature is selected below the sintering temperature.

The aging treatment including the one-step and two-step heat treatments can be performed subsequent to the sintering, or after the sintering, the temperature is once cooled to room temperature and then the temperature is raised again. In either case, the same magnet characteristics can be obtained.

The present invention is not limited to the case of a magnetically anisotropic permanent magnet, and can be applied to the case of a magnetic isotropic permanent magnet without performing a magnetic field during the process, so that the same method can be adopted. Can be expressed. In the case of isotropicity, (BH) max3MGOe or more is obtained in the FeCoBR base composition including R10 to 25%, B3 to 23%, the balance Fe and unavoidable impurities. The isotropic magnet originally has a low characteristic of 1/4 to 1/6 of the magnetic characteristic of the anisotropic magnet, but according to the present invention, nevertheless, it is extremely useful as an isotropic magnet. High characteristics can be obtained.

Also in the isotropic case, iHc increases as the R content increases, but Br decreases after reaching a maximum value. Thus (B
H) The amount of R that satisfies max3MGOe or more is 10% or more and 25% or less.

Further, iHc increases as the amount of B increases, but Br decreases after reaching the maximum value. In order to obtain (BH) max3MGOe or more, the range must be B3 to 23%.

Preferably, the light rare earth is the main component of R (all R in the light rare earth are 5
(0 atomic% or more), R of 12 to 20%, B of 5 to 18%, Co of 35% or less, and FeCoRB base composition of the balance Fe exhibiting high magnetic properties of (BH) max4MGOe or more. As a most preferable range, a light rare earth such as Nd or Pr is used as a main component of R, R of 12 to 16 and B and C of 6 to 18%.
With a FeCoBR base composition of 25% or less and the balance of Fe, (BH) max is 7 MGOe or more, high properties that are unprecedented with isotropic permanent magnet materials can be obtained.

Except for the following, M is preferably in the same range as in the anisotropic case (V10.5% or less, W8.8% or less, Ti4.7.
% Or less, Ni 4.7% or less, Ge 6.0% or less). If any of the M components is isotropic, the B content increases as the amount of addition increases.
r shows a decreasing tendency, and Br3 kG or more (to be equal to or higher than the level of (BH) max2MGOe of isotropic hard ferrite) is shown within this range.

In the case of anisotropy, the binder and the lubricant may not be generally used because they hinder the orientation during molding, but in the case of an isotropic magnet, the binder and the lubricant are included. It is possible to improve the press efficiency and increase the strength of the molded body.

Even in the case of isotropicity, the presence of impurities that are unavoidable in industrial production can be allowed. That is, in addition to R, B, Fe, C within a predetermined range,
P, S, Cu, Ca, Mg, O, etc. may be contained.

As described above in detail, the method for producing a permanent magnet material of the present invention is a novel Fe / Co / B / R / M-based high-coercive force, high residual magnetic flux density, and high-performance magnet having excellent magnet characteristics. The permanent magnet material can be provided especially as a bulk body. Further, by using a light rare earth element such as Nd or Rr as R, a permanent magnet material excellent in terms of both resource and price can be provided, which is highly industrially applicable. In particular, a magnet material having a more practical Curie temperature can be obtained by substituting a part of FeBR-based F with Co, and the inclusion of the predetermined element M can further improve the coercive force. By further performing a predetermined two-step aging treatment, the crystalline FeCoBR-based permanent magnet material based on the FeBR ternary compound is not only a non-aged one but also a one-step aging-treated one. On the other hand, the coercive force and the squareness of the magnetic field curve can be further improved without impeding other magnetic properties.

Hereinafter, aspects and effects of the present invention will be further described according to examples. However, the embodiments and described embodiments do not limit the present invention.

Tables 1 to 4 show various Fe · C produced by the following steps.
The characteristics of a permanent magnet body composed of o-B-R-M composition are shown below.

(1) The starting material has a purity of 99.9% as Fe (weight%,
Hereinafter, the same applies to raw material purity) electrolytic iron, and ferroboron alloy as B (19.38% B, 5.32% Al, 0.7
4% Si, 0.03% C, balance Fe), purity of R is 9
Use 9% or more (impurities are mainly other rare earth metals).

As Co, electrolytic Co having a purity of 99.9% was used.

As M, Ta, Ti, Bi, Mn and S with a purity of 99%
b, Ni, Sn, Ge, 98% W, 99.9% A
Ferro-zirconium containing 95% Hf and 77.5% Zr as Zr, ferrovanadium containing 81.2% V as V, ferroniobium containing 67.6% Nb as Nb and Cr Ferrochrome containing 61.9% Cr was used.

(2) The magnet raw material was melted using high frequency induction. At that time, an alumina crucible was used as a crucible to make a cast ingot in a water-cooled copper mold.

(3) The ingot obtained by melting was ground to -35 me.
After adjusting to sh, the product was further pulverized by a ball mill so that a product having a predetermined average particle size was obtained.

(4) The powder was molded in a magnetic field width at a predetermined pressure (however, when an isotropic magnet was manufactured, it was molded without applying a magnetic field).

(5) The compact was sintered at a predetermined temperature in the range of 900 to 1200 ° C. and in a predetermined atmosphere, and then subjected to a predetermined heat treatment.

Example 1 Atomic percentage composition 64Fe-12Co-9B-14Nd-
Alloy powder having an average grain size of 35 μm of 1 Mo was pressed at a pressure of 1.3 ton / cm ^{2 in} a magnetic field of 12 kOe, and then 9
1120 ° C. in 9.99% pure 200 Torr Ar,
Sintering was performed for 2 hours, and after sintering, the temperature was cooled to room temperature at a cooling rate of 650 ° C./min. Further aging treatment in Ar atmosphere 82
After each hour at 0 ° C, cooling rate is 350 ° C / min for 48 hours.
After cooling to 0 ° C., aging treatment was further performed at 600 ° C. for 2 hours to obtain a magnet according to the present invention. The results of the magnet characteristics and the temperature coefficient α (% / ° C.) of the residual magnetic flux density (Br) are shown in Table 1 together with the values of only one-step aging treatment at 820 ° C. and 1 hr as a comparative example.

Example 2 Atomic percentage composition 54Fe-18Co-10B-14N
An alloy powder having d-1Y-2Nb-1Ge and an average particle size of 2.8 μm was pressure-molded at a pressure of 1.2 ton / cm ^{2 in} a magnetic field of 12 kOe, and then 500 To of 99.999% size.
Sintering was performed at 1140 ° C. for 2 hours in rrAr, and after sintering, the temperature was cooled to room temperature at a cooling rate of 400 ° C./min. 5x more
The first-stage aging treatment was performed in a vacuum of 10 ⁵ Torr at each temperature shown in Table 2 for 2 hours, and the second-stage aging treatment was performed after cooling to 420 ° C. at a cooling rate of 400 ° C./min.
The magnet according to the present invention was obtained by performing the treatment at 0 ° C. for 3 hours. Magnet characteristic results and temperature coefficient α (% / ° C) of residual magnetic flux density (Br)
Is shown in Table 2 together with a comparative example (after one-step aging treatment).

Example 3 Fe—Co—B—R—M alloy powder having an average particle size of 2 to 8 μm and an atomic percentage composition shown in Table 3 was pressure-molded in a 12 kOe magnetic field at a pressure of 1.2 ton / cm ² , and then 9
1100 in 200 Torr Ar with 9.999% purity
Sintered for 2 hours at a temperature of 750 ° C./min.
Rapidly cooled to room temperature. Further, the first aging treatment is performed at 820 ° C. for 2 hours in 450 Torr high-purity Ar,
After cooling to 380 ° C. or less at 250 ° C./min, the second stage aging treatment was performed at 600 ° C. for 2 hours to obtain a permanent magnet according to the present invention. Magnet characteristic results and residual magnetic flux density (Br)
Table 3 shows the temperature coefficient α (% / ° C.) of each of the samples together with the comparative example (after the one-step aging treatment).

Example 4 Fe having the following atomic percentage composition and an average particle size of 1 to 6 μm
-Co-B-R-M alloy powder in a magnetic field of 1.2 ton
After pressure molding at a pressure of / cm ² , it is sintered in 180 TorrAr of 99.999% purity at 1080 ° C. for 2 hours,
After sintering, it was rapidly cooled to room temperature at a cooling rate of 630 ° C / min. Furthermore, the first aging treatment is performed at 850 ° C. for 4 hours in 700 Torr high-purity Ar, and the temperature is increased to 420 ° C. for 38 hours.
After cooling at 0 ° C./min, the second stage aging treatment was further performed at 620 ° C. for 3 hours to obtain a magnet according to the present invention. The results of the magnetic properties are shown in Table 4 together with the sample without the two-step aging treatment (comparative example).

Example 5 A Fe-Co-B-R-M alloy having the following atomic percentage composition was obtained by casting in a water-cooled copper mold after Ar gas induction melting.

The present alloy was roughly pulverized by a stamp mill to 35 mesh or less, and then finely pulverized with an organic solvent width to a ball mill to obtain an average particle size of 2.6 μm. The obtained powder was treated with a magnetic field of 12 kOe for 1.5 t.
After pressure-molding at a pressure of n / cm ² , sintering was performed in 200 Torr Ar having a purity of 99.99% at 1080 ° C. for 2 hours, and after sintering, it was rapidly cooled to room temperature at a cooling rate of 500 ° C./min.

After aging treatment at 800 ° C. for 1 hour in 760 Torr Ar and cooling to room temperature at a cooling rate of 300 ° C./min, further aging treatment at 580 ° C. for 3 hours was performed to obtain a magnet according to the present invention. The magnet characteristic results are shown in Table 5 together with comparative examples (after sintering).

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yutaka Matsuura 2-15-17 Egawa, Shimamoto-cho, Mishima-gun, Osaka Inside Yamazaki Works, Sumitomo Special Metals Co., Ltd. (56) Reference JP-A-60-144909 (JP, A) )

Claims (1)

[Claims] 1. An atomic percentage of 8 to 30% R (where R is Y
At least one of rare earth elements including), 2 to 28%
B, one kind or two kinds or more of additional elements M of not more than a predetermined% (however, excluding M 0%, M is V 9.5% or less, Nb 12.5% or less, Ta 10.5% or less, Mo 9.5% or less, W 9.5% Below, Cr 8.5% or less, Al 9.5% or less, Ti 4.5% or less, Zr 5.5% or less, Hf 5.5% or less, Mn 8.0% or less, Ni 8.0% or less, Ge 7.0% or less, Sn 3.5% or less, Bi 5.0% Hereinafter, Sb is 2.5% or less, Si is 5.0% or less, and Zn is 2.0% or less, and when two or more types of M are included, the total amount of M is less than or equal to a predetermined% of the M elements having the maximum value). And FeBR composed of balance Fe and impurities inevitable in manufacturing
An alloy powder having an FeCoBRM composition in which a part of Fe in the M composition is replaced with 50% or less of Co (excluding 0%) with respect to the total composition, and having an average particle size of 0.3 to 80 μm. Forming step, step of sintering at 900 to 1200 ° C. in a reducing or non-oxidizing atmosphere, 750 to 1 after sintering
After the first heat treatment for 0.5 hours or more at a temperature of 000 ° C, 10 ° C /
75 at a cooling rate of over 2000 min / 2000 ° C / min
Cool the temperature range of 0-700 ℃, and further 480-700
A method for producing a permanent magnet material, comprising a step of performing a secondary heat treatment at a temperature of ° C.