JPS61264133A - Permanent magnet alloy and its manufacture - Google Patents

Abstract

PURPOSE:To obtain a permanent magnet alloy having superior coercive force and high squareness on the demagnetizing curve by compacting and sintering alloy powder having a specified composition consisting of Fe, B and a rare earth element and by heat treating the sintered body in three steps under specified conditions. CONSTITUTION:The composition of alloy powder is composed of, by atom, 8-30% R (one or more kinds of rare earth elements including Y), 2-28% B and the balance Fe. The alloy powder is compacted and sintered, and the sintered body is subjected to primary heat treatment at 750-1,000 deg.C and cooled to <=680 deg.C at 3-200 deg.C/min cooling rate. The sintered body is then subjected to secondary heat treatment at 480-700 deg.C and cooled to <=200 deg.C at 10-2,000 deg.C/min cooling rate. The sintered body is heated again at 10-2,000 deg.C/min heating rate, subjected to tertiary heat treatment at 350-450 deg.C and cooled to <=200 deg.C at 10-2,000 deg.C/min cooling rate.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a rare earth iron/boron permanent magnet material that does not use cobalt, which is expensive and a scarce resource, and a method for producing the same.

[Prior Art] Typical permanent magnets currently used are alnico, hard ferrite, and rare earth cobalt magnets. However, as the raw material situation for cobalt has recently become unstable, the demand for alnico magnets containing 20 to 30% cobalt has decreased, and cheap hard ferrite, which is mainly composed of iron oxide, has become the mainstream magnet material. Became. On the other hand, rare earth cobalt magnets contain 50 to 65% by weight of cobalt and use Sm, which is not contained in rare earth ores, so they are very expensive, but because their magnetic properties are much higher than other magnets, they are mainly used for small size magnets. It is often used in high value-added magnetic circuits.

The present inventor previously proposed a Fe-BR-based (R is at least one kind of rare earth element including Y) permanent magnet as a new high-performance permanent magnet that does not contain expensive Sm or CO (Japanese Patent Application Laid-Open No. 59-1979-1). No. 46008), and by subjecting the Fe-B-R alloy to heat treatment under specific conditions after sintering, so-called aging treatment, the magnetic properties after sintering, especially the coercive force and the squareness of the demagnetization curve, are improved. It was found that this was significantly improved (Japanese Unexamined Patent Publication No. 59-217304).

[Problems to be Solved] The present applicant has further discovered that the coercive force and the squareness of the demagnetization curve can be significantly improved by performing a two-stage heat treatment consisting of specific conditions in the heat treatment process. (Patent Application No. 59-36923). In other words, a permanent magnet produced by two-stage heat treatment under specific conditions after sintering has a coercive force of 1Hc3k.
There is also (7)-1' which has a residual magnetic flux density Br of 4 kG or more and a maximum energy product (B H) max of 4 MGOe or more.

By the way, recently, the use of permanent magnets at high temperatures and applications with strong reverse magnetic fields, such as for competitive magnetic coupling for motors and generators, has been expanding, and magnetic properties, especially coercive force and squareness of demagnetization curve There is a need for excellent permanent magnets.

The present invention is a rare earth material that does not contain Go, which is expensive and a scarce resource.
The object of the present invention is to obtain a permanent magnet in which the coercive force and the squareness of the demagnetization curve are further improved using a new permanent magnet material whose main component is poron-iron. In addition, the present invention has excellent high-temperature resistance characteristics so that it can withstand use at high temperatures, and has a permanent property that can withstand applications with strong reverse magnetic fields. In order to improve the magnetic properties of Fe-B-R alloys within a composition range, powder with a specific particle size is compacted and sintered, and then heat treatment is performed under specific conditions after sintering, especially three-step heat treatment. It has been found that the magnetic properties, especially the coercive force and the squareness of the demagnetization curve, are significantly improved.

That is, in the present invention, R is 8 to 30% as an atomic percentage (however, R
is at least one rare earth element including Y), 2-2
An alloy powder whose main components are 8% B and the balance Fe is shaped and sintered, and after sintering, it is first heat-treated at a temperature of 750 to 1000°C, and then cooled to 680°C or less at a cooling rate of 3 to 2000°C/min. After that, secondary heat treatment at a temperature of 480 to 700°C and a cooling rate of 10 to 2000°C/m1n (7) to 200°C.
After cooling down to below 10~200.0℃/m1n (7
) Raise the temperature at a heating rate of 350 to 450°C.
0-b Provides a permanent magnet material obtained by heating at 200°C under 701 liters. Further, the method for manufacturing a permanent magnet material of the present invention is characterized by including the above-mentioned series of steps.

[Preferred embodiments of the invention] The present invention will be explained in detail below.

The present invention is not limited to magnetically anisotropic permanent magnets, but can also obtain magnetically isotropic permanent magnets by performing molding without applying a magnetic field during the manufacturing process.

In the permanent magnet material of the present invention, B has a coercive force iHc of 5 kO.
In order to satisfy e or more, it is required to be 2% (hereinafter % indicates the atomic percentage in the alloy) or more, and in order to obtain a residual magnetic flux density Br of about 4 kG or more of hard ferrite, it is required to be 28% or less.

As boron B, pure poron or ferroporon can be used, and those containing An, St, C, etc. as impurities can also be used. Further, R is required to be 8% or more in order to have a coercive force of 5 kOe or more.

However, R is flammable (difficult in industrial handling and manufacturing, and also expensive), so it should be kept at 30% or less.

As R, a light rare earth element which is abundant in resources can be used, and since Sm is not necessarily required or does not need to be mainly composed of Sm, the raw material is inexpensive and extremely useful.

The rare earth element R used in the present invention includes Y, and is a rare earth element including light rare earths and heavy rare earths, and one or more of them is used. That is, R is Nd, Pr, La, Ce.
, Tb, Dy, Ho, Er, Eu, Sm, Gd, Pm,
Tm, Yb.

Lu and Y are included. R is Nd, Pr, Dy
, Tb, Ho, etc., and especially Nd, Pr
It is particularly preferable that (Nd+Pr) be 50% or more (particularly 80% or more) of the total R in order to reliably achieve high magnetic properties at low cost. Generally, one type of these R is sufficient, but in practice, a mixture of two or more types (Mitushmetal, didymium, etc.) can be used for reasons such as availability, and Sm, Y, La.

Ce, Gd, etc. are other R, especially Nd, Pr, Dy.

It can be used as a mixture with Tb, Ho, etc.

However, it is better that S m and L a be as small as possible.

BaoR does not need to be a pure rare earth element; it may contain impurities that are unavoidable during manufacturing (other rare earth elements, Ca,
Those containing Mg, Fe, Ti, C, 0, etc.) can also be used. In addition, as R, R1, Dy
, Tb, Gd, and Ho + Nd and Pr as R2
A combination of one or more rare earth elements containing Y other than R1 for a total of 80% or more is most preferable for the effect of increasing tHc. In addition to these B and R, the balance of the magnet material of the present invention is Fe, but there is no problem in that it contains impurities that are unavoidable during manufacturing.

In the basic composition of Fe-B-H, 13-16% R, 6-
11%B is (BH) max35MGOe or more, 13-1
4.5%R96 to 7.5%B is a suitable composition for providing 40 MGOe or more (maximum 45MGOe or more).

Adding a predetermined amount of additive element M to the Fe*BaR-based permanent magnet material of the present invention has the effect of significantly increasing the coercive force and improving the squareness, especially in the maximum Br region. . Increasing the coercive force increases the magnet's stability at high temperatures, expanding its applications. However, as the amount of M added increases, Br decreases, and therefore the maximum energy product (BH) max decreases. (BH)m
Recently, there have been many applications that require a high coercive force Hc even if ax is slightly lower, so alloys containing M are very useful, but (BH)max is particularly useful in the range of 8 M G Oe or more. It is.

In order to clarify the effect of each addition of the additive element M on Br, we measured the change in Br by varying the amount of addition, taking into account a range much higher than about 4 kG of Br in hard ferrite, and (BH)max
Considering the range much higher than about 4 MGOe, the upper limit of the amount of M added is V 8.5% and Nb 12.5 $
, Ta 10.5 LMo 9.5%, W
9.5L Or 8.5%, AI 9.5X
, Ti 4.5L Zr 5.5X, Hf
5.5! , Kn 8.0%, Ni 8.
O! , Ge7. Oz, Sn 3.5L B
i5. O$, Sb 2.5%,
Si is 5.0%, and Zn is 2.0%.

M contains 0%, and one type or two or more types can be added and used. When containing two or more types of M, it generally indicates the intermediate value of the characteristics of each added element, and the content of each element is within the range of the above percentage, and the maximum content is the maximum value among the added elements. 0M is generally effective in small amounts (approximately 0.1 to 3%, however, sb is 1% or less and Zn is 0.35% or less), and is preferably o, i to 35% or less.
1%, V, Nb, Cr, Ta, Mo, W, and AI are preferred.

In the composition of the permanent magnet material of the present invention having FeBR as its main component, the maximum energy [(BH)max is much higher than that of hard ferrite hmite (~4MGOe).

In the magnetically anisotropic permanent magnet according to the present invention, the light rare earth element is contained in an amount of 50% or more of the total R, and 12 to 20% of R14 to
In the case of a composition range of 24% B and the balance Fe, or one or more of the following additive elements M1e to the composition
V e, 5X or less, Nb 8.5$ U or less, Ta
8.5X or less, No 5.5% or less, W 5.5
% or less, Or 4.5X or less, AI 5.5X or less, T
i 3.5X or less, Zr 3.5X or less, If 3.5
% or less, Mll 4.0% or less, Ni 2. Below OX,
Ge 4.0% or less, Sn! , (below H, Bi 3
．． 0X or less, Sb 0.5X or less, Si 4.0% or less,
and M when Zn is 1.0% or less and contains two or more types of M.
(BH)max
is a preferable range showing 17 MGOe. Furthermore, the above R
, 0.2 to 3%, R13 to 19%, 85 to 11%, and the balance is Fe, or the above-mentioned additional element M is added to the composition.
One or more types (o, i ~ 3%, especially 0.1 ~ 1%
), maximum energy product (BH) max 35
This is the most preferable range for exhibiting magnetic properties of MGOe or higher, particularly 42MGOe or higher.

In the case of isotropy, 10-25% R, 3-23% B, balance F
(BH) max4MGOe or more, 12-20
%R15-18%B, balance Fe (BH)max
This will be 5MGOe.

The crystalline phase of the magnet material alloy in this invention is a tetragonal main phase of at least 50 Ma1% or more (preferably 80 MaOI% or more), and the grain boundaries of the main phase are surrounded by at least a non-magnetic phase. is essential for producing sintered permanent magnets with excellent magnetic properties. The non-magnetic phase is mainly an R-rich phase (a metal containing R90 atomic% or more) or a B-rich phase (R2Fe7BB or R,Fe4B).
4, etc.), and even a small amount is effective; for example, l vo 1% or more is a sufficient amount. The central composition of the tetragonal lattice glue is considered to be R2F e +a B. It is believed that the three-stage aging treatment of the present invention provides a more preferable metal structure, thereby providing high magnetic properties.

Furthermore, in the magnetically isotropic permanent magnet according to the present invention, the medium-value rare earth element is 50 atomic % or more) and R16-18 is 12-16%.
% of B and the balance is Fe, or one or two of the same additive elements M as in the case of the anisotropic magnet are added to the composition.
When more than one species is contained, (BH) max is in a preferable range that exhibits extremely high magnetic properties as an isotropic permanent magnet of 8 MGOe or more (maximum 11 MGOe or more). Regarding isotropy, M of 0.1 to 3% is sufficiently effective and 0.
．． It is preferably 1 to 1%, and the preferred elements are the same as in the case of anisotropy.

In the present invention, when the binder and lubricant are anisotropic,
Although it is not generally used because it interferes with orientation during molding,
In the case of an isotropic magnet, it is possible to improve the pressing efficiency and increase the strength of the molded product by including a binder, a lubricant, etc.

The permanent magnet of the present invention can tolerate the presence of impurities that are unavoidable in industrial production, whether it is anisotropic or isotropic. That is, R,
In addition to B and Fe, C1Ca, Mg, P, and Cu within a specified range.
, S, 0, etc. are included L+4. -Tagei 1 company folding ≠ 4 black shields with a flute body and 4 each of C, Ca, and Mg
．． If the content is 0% or less, P, Cu each 3.3% or less, 32.5% or less, 02.0% or less (however, the content is below the maximum value of each element), it is equivalent to hard ferrite. B
r (approximately 4kG) or higher, and as a magnetic material,
Useful. However, the levels of these impurities are determined depending on the desired properties. Especially (BH)max35M
In order to achieve magnetic properties higher than GOe, O, C, C
It is preferred to keep the content of a particularly low. Ca, Mg
, P, Cu, etc. may be mixed in from inexpensive raw materials, C may be mixed in from organic molding aids, etc., and S, 0 may be mixed in from the manufacturing process.

The permanent magnet material of the present invention is obtained by the specific manufacturing method described above.

The manufacturing method of the present invention comprises forming and sintering the alloy powder having a composition mainly composed of FeBR, and after sintering, heat-treating it at a temperature of 750 to 1000°C for 1 time, and then cooling it at a cooling rate of 3 to 2000'O/min to 680°C. 'After cooling to below 0, 480-700℃
After the second heat treatment at a temperature of lO~2000℃/min to 200℃ or less, the temperature was raised again at a temperature increase rate of 10~b and after the third heat treatment at a temperature of 350~450℃, the temperature was 10~2000℃. 20 at a cooling rate of °C/min
It is characterized by cooling to 0″C or less.

The alloy powder preferably has an average particle size of generally 93 to 80 feed weight. It is possible to make the powder even finer if a completely non-oxidizing atmosphere is ensured, but since the powder is extremely oxidizing, it will oxidize and ignite, so under normal conditions it will weigh less than 0.3g.
The f: & shape sintering step, which is preferably m or more, is generally press forming (in a magnetic field in the case of anisotropy, without a magnetic field in the case of isotropy) and sintering. Sintering is preferably carried out in a reducing or non-oxidizing atmosphere (in vacuum or in an inert gas atmosphere under reduced pressure, normal pressure or pressure) at a temperature of 900-1200°C, in the case of sintering at a relatively low temperature. It is necessary to sinter for a long time.

The manufacturing method of the present invention will be explained below based on experimental examples in the case of magnetically anisotropic permanent magnets.

As starting materials for the experiment, Fe is electrolytic iron with a purity of 99.0% or more, B is pure poron with a purity of 99.0% or more and ferroporon with a purity of 90.0% or more, and R is one with a purity of 95% or more. used.

These raw materials are blended within the above range and melted using high frequency in a vacuum or inert gas atmosphere.

The alloy is melted and alloyed by arc melting, etc., and the resulting alloy is coarsely crushed using a stamp mill, show crusher, etc. to obtain a coarsely ground powder, or alternatively, the oxide is converted from an oxide using a reducing agent such as Ca. A coarsely pulverized powder may be obtained by a reduction method, and the coarsely pulverized powder thus obtained is further pulverized using a jet mill, a ball mill, or the like. For fine pulverization, either dry pulverization in an inert gas atmosphere or wet pulverization in an organic solvent such as acetone or toluene can be used. The alloy powder obtained by fine pulverization has an average particle size of 0.
．． 3 to 80 ILm. If the average particle size is less than 0.3 pm, the oxidation of the powder will be significant during the pulverization or subsequent steps, the density after sintering will not increase, and the resulting magnetic properties will be poor. If the average particle size exceeds 80 .mu.m, the average particle size of the fine powder is preferably 1 to 40 pm, and most preferably 2 to 20 gm, in order to achieve excellent magnetic properties. Average particle size 0
．． In the case of forming an anisotropic magnet, 3 to 80 gm of powder is pressure-molded in a magnetic field (for example, 5 kOe or more). The pressure used for molding is preferably 0.5 to 3.0 tons/cm2.

For pressure molding in a magnetic field, either a method of molding the powder as it is or a method of molding it in an organic solvent such as acetone or toluene can be used. The obtained molded body is heated to 99.9% in a reducing or non-oxidizing atmosphere, for example in a vacuum of 10" Torr or less or under a pressure of 1 to 760 Torr.
90% or more in an atmosphere of inert gas or reducing gas
Sintering is performed at a temperature of 0 to 1200°C for a predetermined time. If the sintering temperature is less than 900° C., sufficient sintered density and high residual magnetic flux density cannot be obtained. Moreover, if the temperature exceeds 1200° C., the sintered body is deformed and the orientation of crystal grains is lost, resulting in a decrease in residual magnetic flux density and a decrease in the squareness of the demagnetization curve. Also, the sintering time should be at least 5 minutes, but if it is too long, 4 hours is preferable from the viewpoint of mass production.The sintering atmosphere should be a non-oxidizing atmosphere since R in the composition is extremely easily oxidized at high temperatures. It is preferable to ensure a high degree of atmosphere such as high vacuum, inert gas, or reducing gas. When an inert gas is used, the sintering can be carried out under a reduced pressure atmosphere of 1 to 760 Torr without swirling in order to obtain a high sintering density.

There is no need to specify the temperature increase rate during sintering, but if a wet molding method is used, the rate of temperature increase during sintering is 40℃/30℃ to remove the organic solvent.
Raise the temperature within minutes or 200~800℃ during heating.
It is preferable to hold the temperature in the 0°C temperature range for 0.5 hours or more. When cooling after sintering, a cooling rate of 20°C/min or higher is preferable in order to reduce product variation, and in order to improve the magnetic properties due to aging treatment in the subsequent heat treatment, the cooling rate after sintering is preferably 100°C/min. The above is preferred, however, it is also possible to immediately enter a heat treatment step following sintering.

The heat treatment after sintering consists of the following steps. First, the sintered body 7
After the first heat treatment at a temperature of 50 to 1000℃, 3
~b After cooling to below 680°C, a second heat treatment is performed at a temperature of 480 to 700°C, and then a temperature of 10 to 2000°C/m
Cool down to 200°C or less at a cooling rate of 100°C, then raise the temperature again at a rate of 10°C to 450°C, perform a third heat treatment at a temperature of 350°C to 450°C, and It consists of cooling to below 200°C at a cooling rate.

If the first stage heat treatment temperature is less than 750°C, the first stage heat treatment will not be effective and the obtained coercive force will be low;
If it exceeds this value, grain growth will occur in the crystals of the sintered body and the coercive force will decrease.

The cooling rate after the first stage heat treatment is 3°C/min.
If it is less than 20, the coercive force and the squareness of the demagnetization curve will decrease.
When the temperature exceeds 00° C./mtn, micro-cracks occur in the sintered body and the coercive force decreases. The temperature range in which this predetermined cooling rate should be maintained is limited to a range from the first stage heat treatment temperature to 680° C. or less. As for the cooling rate of 680° C. or less, both slow cooling and rapid cooling are possible. When the lower limit of the cooling temperature range at a predetermined cooling rate is 680° C. or less, the coercive force decreases significantly.

In the second stage heat treatment, after the first heat treatment, the temperature is further cooled to 480 to 700 degrees Celsius by a prescribed rapid cooling process to below 680 degrees Celsius.
The temperature range is as follows. If the secondary heat treatment is performed by cooling such as furnace cooling after the primary heat treatment, the obtained magnetic properties are poor.

Note that the secondary heat treatment can be performed following the predetermined cooling after the primary heat treatment, but it can also be performed after the predetermined cooling and cooling.

The second stage heat treatment temperature is limited to 480 to 700°C. 4
If the temperature is lower than 80°C or higher than 700°C, the coercive force and the squareness of the demagnetization curve will decrease.

After the second heat treatment, it is cooled to below 200°C at a cooling rate of 10 to 2000°C/min, and then heated again to 10°C/min. The cooling rate and heating rate are 10°O/min. The squareness of the magnetic curve decreases. The temperature range in which this predetermined cooling rate should be maintained is limited to a range from the second stage heat treatment temperature to 200° C. or less. 200℃
As for the cooling rate below, both slow cooling and rapid cooling are possible. When the lower limit of the cooling temperature range at a predetermined cooling rate is 200° C. or higher, the coercive force and the squareness of the demagnetization curve are significantly reduced.

In order to improve magnetic properties and reduce variations, the lower limit of the cooling temperature range at a predetermined speed is preferably 150°C or less, and most preferably 100''C or less.

In order to increase the squareness of the coercive force and demagnetization curve and reduce variations in magnetic properties, the cooling rate after the second heat treatment and the subsequent temperature increase rate are preferably 20 to 1500'C/min, and preferably 40 to 2000C. /min is most desirable.

The feature of wood 3-stage heat treatment is 200'C after secondary heat treatment at a temperature of 480 to 700 degrees Celsius! Cool to below 300℃
After passing through a temperature range of ~250°C by prescribed rapid cooling,
After raising the temperature to the stage heat treatment temperature, the temperature was raised within a predetermined temperature range of 350 to 450'O, which is effective for improving the coercive force and the squareness of the demagnetization curve, and after 3-fire heat treatment, the temperature was increased to 10 to 2000 °C.
The objective is to cool down to 200°C or less at a cooling rate of /min. If the temperature is subsequently raised by cooling such as furnace cooling after performing secondary heat treatment, the increase in magnetic properties obtained will be small. When heating up to temperature, and after heating up 2
When cooling down to 00°C or lower, cooling and temperature raising are performed at a predetermined rate in order to eliminate the influence of the metal phase instability region that deteriorates the magnetic properties between 250 and 300°C.

Is Umono.

Note that the temperature increase can be performed following the predetermined cooling after the secondary heat treatment, but it can also be performed after the predetermined cooling and cooling.

The third stage heat treatment temperature is limited to 350 to 450°C. 3
If the temperature is less than 50°C or more than 450°C, the coercive force and the squareness of the demagnetization curve will decrease. In order to improve the squareness of the coercive force and demagnetization curve and reduce the variation in magnet characteristics, 3.
The temperature range for the stage heat treatment is preferably 360 to 440°C, and most preferably 375 to 425°C.

The first stage heat treatment time is not particularly limited, but it is difficult to control the temperature in a short time, and the industrial merit decreases in a long time, so it should be 0.5 to 8. Ohr is preferred.

The heat treatment times for the second and third stages are also not particularly limited, but similarly, it is difficult to control the temperature if it is short, and the industrial merits are reduced if it is long, so it is 0.5 to 12. Ohr is desirable, especially for the third stage heat treatment time, in order to improve the coercive force and the squareness of the demagnetization curve, it is 1.0 to 6. Ohr is most preferred.

The atmosphere for aging treatment is vacuum degree 1O-3 because R in the alloy composition reacts rapidly with oxygen or moisture at high temperatures.
Torr or less, in the case of an inert gas or reducing gas atmosphere, the purity of the atmosphere is preferably 99.99% or more. Note that 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.

In addition, the aging treatment including these 1-stage, 2-stage, and 3-stage heat treatments can be performed following sintering, or can be performed by cooling to room temperature after sintering and then raising the temperature again; in either case, the results are the same. magnetic properties are obtained.

However, once cooled to room temperature, 200% lower than the sintering temperature.
The temperature range up to 'C or less shall be cooled at a cooling rate of 10 to b/min.

In addition, if a magnetic field is applied in the third aging treatment step of the present invention, magnetic properties equivalent to or better than those without a magnetic field can be obtained, but when carried out with a magnetic field applied, 5 kOe is required to improve the magnetic properties. A magnetic field larger than this is required. Further, it is particularly desirable to apply a magnetic field within a temperature range of 200 to 350° C. in order to improve magnetic properties, especially coercive force.

The above has been described for the case of magnetically anisotropic permanent magnets, but
The present invention is not limited to the case of magnetically anisotropic permanent magnets, but also to the case of magnetically isotropic permanent magnets, by performing molding during the process without applying a magnetic field.
The magnetic properties of the new permanent magnet material, which is mainly composed of Fe/B-R and does not contain any It is a permanent magnet and has extremely high industrial value.

Hereinafter, aspects and effects of the present invention will be further explained according to examples. However, the present invention is not limited to the examples and described aspects.

Example 1 An alloy having an atomic percentage composition of 73FelOB9Nd8Pr was melted in an Ar gas arc and then cast into a water-cooled copper mold.

After coarsely pulverizing this alloy to 40 me s h or less using a stamp mill, it was pulverized in an organic solvent to an average particle size of 2.5 μm.
Mill pulverized. The obtained powder was heated at 1 in a 15 kOe magnetic field.
．． After pressure molding at a pressure of 5 tons/crrr', 99
．． 999% purity (7) 220 T o r r A
The mixture was cooled to 1100° C. for 2 hours in a r. 3X more
First stage aging treatment at 820℃ in 10'Torr vacuum
600°C at a cooling rate of 400°C/min for 2 hours.
After cooling to below ℃, a second aging treatment is performed at 620℃.
°C for 14 hours, then cooled to 150 °C at 400 °C/min, then heated at 50 °C/min, and performed the third aging treatment at the temperature shown in Table 1 for 2 hours.
The magnet of the present invention was obtained by cooling to 150°C at a rate of °C/min.

The magnet characteristics results are shown in Table 1 along with a comparative example (magnet subjected to two-stage aging treatment).

Table 1 Example 2 An Fe-B-R alloy having the atomic percentage composition shown in Table 2 was melted in an Ar gas arc and then cast into a water-cooled copper mold.

This alloy was coarsely ground to a size of 50 mesh or less using a stamp mill, and then finely ground using a pole mill to an average particle size of 3.2 pm in an organic solvent. The obtained powder was heated to ff1l in a 15kOe magnetic field.
, After pressure molding at a pressure of 5 tons/cm',
10 in 99.999% pure 180 Tor rAr
Sintered at 80℃ for 3 hours, cooling rate 800℃/m after sintering
It was rapidly cooled to room temperature by in. Another 500 Torr
The first aging treatment was performed at 800°C for 3 hours in high-purity Ar, and after cooling to 630°C or less at 350°C/min, the second aging treatment was performed at 600°C for 4 hours. After cooling to 120℃ at ℃/min, the temperature was raised at 80℃/min and the third aging treatment was performed at 400℃.
C. for 1 hour, and then cooled to 120.degree. C. at 250.degree. C./1 sin to obtain the present alloy magnet. Comparative example of magnet characteristics results (
These are shown in Table 2 along with magnets subjected to two-stage aging treatment.

Table 2 Example 3 An Fe-B-R alloy having the following atomic percentage composition was melted in an Ar gas arc and then cast into a water-cooled copper mold. This alloy was coarsely pulverized by a stamp mill to a particle size of 35 sesh or less, and then finely pulverized by a pole mill to an average particle size of 3.5 gm in an organic solvent. The obtained powder was heated at 1.0 ton/c in a non-magnetic field.
After pressure molding at a pressure of m', 99.99% purity (7)
Sintering was performed at 1080° C. for 4 hours in 180 TorrAr, and after sintering, it was rapidly cooled to room temperature at a cooling rate of 300° C./min. Paring at 800℃ for 2 hours, 25
After cooling to 600°C or less at a cooling rate of 0°C/min, a second aging treatment was performed at 600°C for 1 hour.
After cooling to 100'C! at 0()''0/min 10
Raise the temperature at 0°C/min and perform the third aging treatment at 400°C.
The results of the characteristics of the 6m stone obtained by cooling the magnet at 200'C/min to 150°C for 1 hour are shown in Table 3 together with a sample subjected to two-stage aging treatment (comparative example).

Table 3 Example 4 An Fe-B-R alloy having the following atomic percentage composition was high-frequency melted in Ar gas and then cast into a water-cooled copper mold.

After coarsely pulverizing this alloy to a size of 35 mesh or less using a stamp mill, the average particle size was 2.5 mm in an organic solvent. Ball milled to OBm. The obtained powder was heated to 1.5t in a 15koe magnetic field.
After pressure molding at a pressure of on/cm', sintering was performed at 1060° C. for 2 hours in 200 TorrAr with a purity of 99.99%, and after sintering, it was rapidly cooled to room temperature at a cooling rate of 500° C./min.

Further, 1 hour at 800°C in 760 TorrAr
After performing a stage aging treatment and cooling to room temperature at a cooling rate of 300°C/win, a second stage aging treatment was performed at 620°C for 3 hours, cooling to 100°C at a rate of $400°C/min, and then to 120°C. The temperature was raised at 375℃/min for 1 hour, and then the temperature was increased to 200℃/min for 1 hour.
The magnet was cooled to 150° C. to obtain a magnet of the present invention.

Table 4 shows the magnet characteristics results along with a comparative example (after two-stage aging treatment).
Shown below.

Table 4 (1 yen 3) Example 5 Fe-BRM alloy powder having an average particle size of 1 to 6 gm and the atomic percentage composition shown in Table 5 was heated in a 15 kOe magnetic field for 1.5 gm.
After pressure molding at a pressure of 5 Ton/am'', 99.
999% purity cy) 1100°C in 180TorrAr
Sintered for 12 hours, cooling rate 600'C/min after sintering
It was rapidly cooled to room temperature. Furthermore, aging treatment was performed at 800°C for 2 hours in high purity Ar at 550 Torr.
600℃ after cooling to 550℃ or less at 00℃/win
, 350℃/m after 2hr second aging treatment
150'O/min after cooling to 120℃
The temperature was raised at It is shown in Table 5 along with the magnet properties after treatment.

Table 5 (Note) The remaining Fe is Example 6 A Fe-BRM alloy having the following atomic percentage composition is
After high-frequency melting in r gas, the product was cast in a water-cooled copper mold.

This alloy was coarsely pulverized to a size of 35 mesh or less using a stamp mill, and then finely pulverized by a ball mill in an organic solvent to an average particle size of 2.54 m. The obtained powder was placed in a 12 kOe magnetic field.
, 1 l in 200 TorrAr with 99.999% purity after pressure molding at 5 t On/cm2(y) pressure.
oo℃, sintering for 2 hours, cooling rate 600℃ after sintering
/min to room temperature.

Further, 1 hour at 800°C in 760 TorrAr
After performing a stage aging treatment and cooling to room temperature at a cooling rate of 250°C/min, a second stage aging treatment was performed at 600°C for 2 hours, and then a cooling rate of 120°C at 450°C/min was performed.
After cooling to ℃, the temperature was raised at 150℃/min, and the third aging treatment was performed at 38α℃ for 4 hours, and then heated to 250℃/min.
The magnet of the present invention was obtained by cooling to 150° C. at min.

Table 6 shows the magnet characteristics results along with a comparative example (after two-stage aging treatment).
Shown below.

Table 6 Applicant: Sumitomo Special Metals Co., Ltd. Agent: Patent attorney Asami Kato (1 other person)

Claims (4)

[Claims] (1) Forming and sintering an alloy powder whose main components are 8 to 30% R (where R is at least one rare earth element including Y), 2 to 28% B, and the balance Fe as atomic percentages, 3 After primary heat treatment at a temperature of 750-1000℃ after sintering
After cooling to 680°C or less at a cooling rate of ~2000°C/min, secondary heat treatment was performed at a temperature of 480 to 700°C for 10
Cool to 200°C or less at a cooling rate of ~2000°C/min, then raise the temperature again at a heating rate of 10~2000°C/min, and perform a tertiary heat treatment at a temperature of 350~450°C.
Permanent magnetic material made by cooling to 200°C or less at a cooling rate of 2000°C/min. (2) Permanent magnet material according to claim 1, characterized in that, in place of a part of the Fe, one or more of the following additive elements M are contained in a total of 3 atomic % or less based on the total composition: V , Nb, Ta, Mo, W, Cr, Al, Ti, Zr, Hf, Mn, Ni, Ge, Sn, Bi, S
b, Si, and Zn (however, Sb is 1% or less, Zn is 0.
5% or less). (3) Process of forming and sintering an alloy powder whose main components are 8 to 30% R (R is at least one of rare earth elements including Y), 2 to 28% B, and the balance Fe as atomic percentages. , After sintering, first heat treatment at a temperature of 750 to 1000°C, followed by cooling to 680°C or less at a cooling rate of 3 to 2000°C/min, and second heat treatment at a temperature of 480 to 700°C, at a cooling rate of 10 to 2000°C/min. A step of cooling down to 200℃ or less at a cooling rate of 10 to 2000℃.
A permanent magnet material characterized by comprising a step of heating at a heating rate of 10°C/min, tertiary heat treatment at a temperature of 350 to 450°C, and cooling to 200°C or less at a cooling rate of 10 to 2000°C/min. Production method. (4) Instead of a part of the Fe, one or more of the following additive elements M are contained in the following predetermined percentage or less based on the total composition (however,
4. The method according to claim 3, wherein when two or more types of additive elements M are included, the amount is less than or equal to the largest of the following predetermined percentages of the contained additive elements. V9.5%, Nb12.5%, Ta10.5%, Mo9
．． 5%, W9.5%, Cr8.5%, Al9.5%, T
i4.5%, Zr5.5%, Hf5.5%, Mn8.0
%, Ni8.0%Ge7.0%, Sn3.5%, Bi5
．． 0%, Sb2.5%, Si5.0%, and Zn2.0
%.