JPH02217406A - Manufacture of rare-earth-metal-fe-b series permanent magnet powder - Google Patents

Abstract

PURPOSE:To obtain magnet powder having high magnetic characteristic by executing heat treatment and de-hydrogen treatment under the prescribed conditions to powder obtained by mixing hydride powder of one or more kinds of rare earth elements (R) containing Y, ferro boron powder and iron powder at the prescribed ratios. CONSTITUTION:By atomic %, 10-30% hydride powder of R, 3-30% ferro boron powder and the balance the iron powder are blended to obtain the mixed powder having 0.5-100mum average particle size. The heat treatment is executed at 500-1,100 deg.C under atmosphere of hydrogen gas or mixed gas of the hydrogen gas and inert gas to this powder. Successively, the de-hydrogen treatment is executed at 500-1,000 deg.C, and after making vacuum atmosphere at <=1Torr hydrogen gas pressure or inert gas atmosphere at <=1Torr hydrogen gas partial pressure, this powder is cooled.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention mainly relates to R-Fe, which is composed of at least one rare earth element containing Y (hereinafter referred to as R), Fe and B.
- Powder for producing a B-based bonded magnet or permanent magnet (hereinafter referred to as R-Fe-B-based permanent magnet powder) is R powder or R hydride (hereinafter referred to as RHx) powder,
The present invention relates to a method for producing B powder or ferroboron powder and Fe powder from raw material powders.

[Conventional technology]

Conventionally, R-Fe-
As a method for producing B-series permanent magnet powder, the above-mentioned powders are blended in a predetermined ratio, mixed well, and further ground with a ball mill or the like to uniformly mix and refine the above-mentioned element powders.
A method of producing R-Fe-B permanent magnet powder by a mechanical alloying method is known (Japanese Patent Laid-Open No. 62-240742).
(see publication).

[Problem to be solved by the invention]

According to the method described in JP-A-02-240742, R-Fe-B permanent magnet powder is ground in an inert gas to prevent the powder from oxidizing during grinding with a ball mill or the like. be done. However, since the upper frame is formed using a ball mill or the like in the mechanical alloying method for a long time of about 10 to 30 hours, contamination with impurities due to wear of the balls is unavoidable, and even when ground in an inert gas, However, a small amount of oxidation of the powder is unavoidable, and therefore, the R-Fe-B permanent magnet powder obtained by this method has a problem in that its magnetic properties vary.

[Section ffi? Means to solve]

Therefore, the present inventors conducted research to solve such problems, and as a result, prepared R powder or RHx (0<X≦3) powder, ferroboron powder, and iron powder as raw material powders, and In atomic percentage, R powder or RHx (0x≦3) powder = lO~30
%, ferroboron powder = 3-30%, iron powder: balance, average particle size obtained by blending and mixing: 0.5
The mixed powder for ~100 μs is heat-treated at a temperature of 500 to 1000°C in a hydrogen gas atmosphere or in a mixed atmosphere of hydrogen gas and inert gas, and then at a temperature of 500 to 1000°C and a hydrogen gas pressure of 1 Tor.
After dehydrogenating until it becomes a vacuum atmosphere of r or less or an inert gas atmosphere of hydrogen gas partial pressure: 1 Torr or less,
Cool or prepare RHx (0x≦3) powder, ferroboron powder and iron powder, and calculate these powders in atomic percentages: RHx (0x≦3) powder: 10-30%, ferroboron powder; 3-30%, iron powder: balance, average particle size obtained by mixing: 0.5
~100 w @ mixed powder, humidity: 500 ~ 1000
°C, hydrogen gas pressure: 1 Torr or less vacuum atmosphere or hydrogen gas partial pressure: 1 Torr or less, if the dehydrogenation treatment is performed until it becomes an inert gas atmosphere and then cooled, no impurities will be mixed in, and the process will be carried out in a hydrogen atmosphere. They found that it is possible to obtain an excellent R-Fe-B permanent magnet without even the slightest oxidation of the powder.

This invention was made based on this knowledge, and the reason for limiting the above range will be explained below.

(a) RHx (0<X≦3) powder or R powder R is preferably Nd and Pr, or a mixture thereof, and also includes Y, Tb, Dy, La, and Ce.

Ho, Er, Eu, Ss, Gd,
Tm, Yb.

It may also contain rare earth elements such as Lu. Among them, 'rb, Dy and Pr are particularly effective in improving the coercive force IHc.

In the method for producing R-Fe-B permanent magnet powder that includes a step of heat treatment in a hydrogen gas atmosphere or a mixed atmosphere of hydrogen gas and an inert gas, RHx (0
<X≦3) It does not need to be a powder, and the effect will not be lost even if it is an R powder, but when the above RHx powder is used as a starting material, the above heat treatment step is omitted and the hydrogen gas pressure is directly applied.
Vacuum atmosphere below 1 Torr or hydrogen gas partial pressure: 1T
It is also possible to produce R-Fe-B permanent magnet powder by dehydrogenating it until it becomes an inert gas atmosphere of orr or less,
Furthermore, since RHx is produced by making R absorb hydrogen, it is originally in a powder state, and the pulverization step can be omitted, so it is preferable to use RHx powder as the starting material.

In the RHx powder, the reason why X was set to O<X≦3 was not particularly significant, and since X in the hydride of R: RHx was generally 3 or less, it was limited to O<X≦3.

The above RHx (0<X≦3) or the blending amount of R powder is 1
If the content is lower than 0 at%, the coercive force of the permanent magnet powder will decrease and high magnetic properties will not be obtained.On the other hand, if the content is higher than 30 at%, the magnetization value of the permanent magnet powder will decrease and high magnetic properties will not be obtained. is not obtained.

(b) Ferroboron powder As the ferroboron powder, Fe 2 B powder is particularly preferred, but some or all of the Fe 2 B may be replaced by FeB.
.

It may be replaced with B. In addition, some of them are Fe-C,
You may substitute with a compound of Fe-N, Fo-0, or Fe-F.

If the blending amount of ferroboron powder is lower than 3 atomic %, the coercive force of the permanent magnet powder will decrease and high magnetic properties will not be obtained;
Ferroboron powder was set at 3 to 30 atom % because even if it was blended in an amount exceeding 30 atom %, the magnetization value of the permanent magnet powder would decrease and high magnetic properties could not be obtained.

(e) Iron powder As the iron powder, it is preferable to use pure iron powder such as electrolytic iron powder, but part of it may be replaced with 50 atomic % or less Co powder, and further part of it may be replaced with C1Mg, All ,Si,
P, S, Ca, TI, V.

Cr, Mn, Ni, Cu, Zn, Ga, Ge.

Sr r Zr , Nb 1Mo j pb l
Ag*Cd.

In, Sn, Sb, Ta, W, Re, Os, Pt.

It may be substituted with Au or Pb. Among these substitutional elements, Co, C, AfI, Tl, V.

Cr, Sl, Ga, and Nb have the effect of improving coercive force IHc.

(d) Mixing of the powders (a) to (e) above and average particle size of the mixed powder Although the mixing in the production method of the present invention may additionally involve pulverization, the main purpose is to homogeneously mix each of the above elemental powders. For example, the mixing time in a ball mill is 1
It may take about 0 to 60 minutes. Mixing for a long time is undesirable because it involves oxidation and contamination of impurities.

The average particle size of the mixed powder consisting of R or RHx (0<X≦3) powder, ferroboron powder, and iron powder is 0.5
- If the size is smaller than 1100tII, the powder will become active and difficult to handle.On the other hand, if it is larger than 1100tII, the alloy composition after heat treatment in a hydrogen gas atmosphere or a mixed atmosphere of hydrogen gas and inert gas will become inhomogeneous, making the magnet powder The average particle size of the mixed powder is between 0.5 and 1 to prevent the properties of
It was set to 00 μs.

(e) Heat treatment A green compact of the above mixed powder is heated in a hydrogen gas atmosphere or a mixed atmosphere of hydrogen gas and inert gas at a temperature of 500 to 100.
Heat treatment is performed at 0°C, but if the heat treatment temperature is lower than 500°C, there will be no hydrogen treatment effect, while if it is higher than 1000°C, the powders will weld together and the coercive force will decrease. was set at 500 to 1000°C. In the heat treatment within the range of 500 to 1000°C, the temperature may not only be maintained at a constant temperature within the range of 500 to 1000''C, but may also be increased or decreased within the temperature range. The above-mentioned temperature increase change or temperature decrease change may be a linear temperature increase or temperature decrease change, but may also be a curvilinear temperature increase or temperature decrease change.Furthermore, the above temperature: 5
The temperature may be changed within the range of 00 to 1000°C by any combination of temperature increase, constant temperature maintenance, and temperature decrease.

The atmosphere of the heat treatment step is a hydrogen gas atmosphere or a mixed atmosphere of hydrogen gas and inert gas, and the hydrogen gas pressure or hydrogen gas partial pressure is at least 10 Torr.
It is preferable to carry out the process under the above conditions. The hydrogen gas pressure or hydrogen gas partial pressure may be at least 10 Torr, but preferably from 10 to 730 Torr to obtain island characteristics.

The atmosphere during heating from room temperature to the above temperature: 500 to 1000°C does not necessarily have to contain hydrogen gas, but may contain other A
An inert gas such as r, He, or a vacuum may be used, but hydrogen gas is preferable. Above temperature: 500-1000
Hydrogen gas is essential when maintaining the temperature at ℃. Further, by adjusting the holding temperature of 500 to 1000°C, holding time, and hydrogen gas pressure, the coercive force and magnetic anisotropy of the obtained magnet powder can be controlled.

(“) Dehydrogenation treatment Dehydrogenation treatment aims at almost complete dehydrogenation of the above-mentioned alloy magnet powder, and the hydrogen gas pressure or partial pressure is 1To
If it is higher than rr, dehydrogenation will be insufficient and high coercive force will not be obtained. For this purpose, the dehydrogenation treatment is performed at a temperature of 500 to 1000° C. until a vacuum atmosphere with a hydrogen gas pressure of 1 Torr or less or an inert gas atmosphere with a hydrogen gas partial pressure of 1 Torr or less is created. This dehydrogenation treatment pattern is as described above (e
) Similar to the heat treatment process, the above temperature: 500 to 1000°C
In addition to maintaining the temperature at a constant temperature within the range of The temperature may be varied by any combination of heating, maintaining a constant temperature, and decreasing the temperature. The dehydrogenation temperature is 5
If it is lower than 00℃, the dehydrogenation treatment will not be effective and R-Fe-B
If the temperature is higher than 1000°C, the powders will weld together and the coercive force will decrease.

Note that although the temperature ranges of the above steps (e) and (1') are the same, dehydration is not necessarily carried out by maintaining the same temperature in a hydrogen gas atmosphere or a mixed atmosphere of hydrogen gas and inert gas. You don't have to be basic. For example, dehydrogenation may be carried out by further raising and lowering the temperature from the temperature maintained in a hydrogen gas atmosphere or a mixed atmosphere of hydrogen gas and an inert gas; It is preferable to perform the dehydrogenation treatment at the temperature of the heat treatment in an atmosphere.

Further, after the steps (e) and Cr") are completed, the steps (e) and (4) may be repeated.

(g) Cooling after dehydrogenation treatment After the dehydrogenation treatment in (f) above is completed, immediately cool it with an inert gas such as Ar, or maintain it at a constant temperature in vacuum or in an inert gas during cooling. Heat treatment. The purpose of this heat treatment is to further improve the coercive force of the magnetic powder obtained through the steps (e) and (f) above.
Do this as necessary. The above heat treatment temperature is 300 to 100
The temperature range is 0°C, more preferably 550 to 700°C. Such heat treatment may be performed by cooling to room temperature with the inert gas and then heating again in a vacuum or in an inert gas, and may be performed not only once but twice or more.

It is desirable that the cooling after the dehydrogenation and heat treatment be as fast as possible.

〔Example〕

Next, the present invention will be explained in more concrete detail based on Examples and Comparative Examples.

Examples 1-12 and Comparative Examples 13-16 Purity 99.9%
The rare earth metals (bulk) of Nd, Pr, Y, Dy are first
Weigh in the proportions shown in the table, and at a temperature of 30°C in 1 atm of hydrogen.
RHx powder having the X value shown in Table 1 was prepared by holding at 0°C for 2 hours, and the purity was 99.9.
F e 2 B powder with a particle size of 400- or less, CO powder with an average particle size of 100- or less as a replacement powder,
and purity: 99. Particle size: 400 with Qffi amount%
．． Electrolytic iron powder with a size of less than cm was prepared and used as a raw material powder.

These raw material powders were blended to have the composition shown in Table 1, mixed in a ball mill, and average particle size: 30-
It was made into a mixed powder. When this mixed powder was subjected to powder X-ray diffraction and phase identification was performed, it was found that RHX, Fe 2 B
, Co and Fe diffraction lines were observed.

This mixed powder was molded with a pressure crab of 4Ton/c- to form a green compact, heat treated in hydrogen at a temperature of 2,840°C and 1 atm, and then dehydrogenated to a temperature of 870°C and 5 X lO'Torr. The mixture was cooled and crushed to obtain R-Fe-B permanent magnet powder. When R-Fe-B permanent magnet powder was produced from the above mixed powder, the yield was 97% or more in all cases.

The obtained R-Fe-B permanent magnet powder was measured for iHc at a magnetizing magnetic field of 40 koo using a vibrating magnetometer (VSM), and the results are shown in Table 1. Linear diffraction was performed to identify the ferromagnetic phase: R2Fe14B. The above powder X-ray diffraction results are as follows: ◎ indicates that only the diffraction lines of the ferromagnetic phase R2Fe, 4B are confirmed, and almost no diffraction lines of other phases are observed. 0 indicates that the diffraction line of the ferromagnetic phase R2Fe14B is confirmed. , X, in which diffraction lines of other phases are also clearly observed, and X, in which diffraction lines of the ferromagnetic phase R2Fe14B are hardly observed, are shown in Table 1 as ◎, 0, and X.

Furthermore, the obtained R-Fe-B permanent magnet powder,
Mixed with 3% by weight epoxy resin, pressure crab 77on/c
- and heat cured at 120°C for 5 hours to produce an isotropic bonded magnet, and using a self-recording magnetometer, magnetization magnetic field: 4
The magnetic properties of the bonded magnets at G koe were measured, and the results are also shown in Table 1.

From the results in Table 1, Examples 1 to 1 that meet the conditions of this invention
The R-Fe-B permanent magnet powder produced in No. 12 shows high coercive force, and the bonded magnet made with this magnet powder also shows high magnetic properties. It can be seen that those that deviate from the conditions do not exhibit sufficient magnetic properties.

Examples 17-28 and Comparative Examples 29-32 Above Example 1
The mixed powders of ~12 and Comparative Examples 13~16 were crushed under pressure 4
The green compact molded with Ton/cd was heated with a pressure crab lX at room temperature.
It is maintained in a vacuum of 10''5 Torr, and then immediately inserted into a heat treatment furnace at a temperature of 2870°C.
After dehydrogenating at 5 x 10"" Torr at ℃, cooling, and crushing, R-Fe-B permanent magnet powder was obtained. R-Fe-B permanent magnet powder was produced from the mixed powder. The yield in all cases was 9G% or higher.

Regarding the obtained R-Fe-B permanent magnet powder, IHc at a magnetizing magnetic field of 40 kOe was measured under the same conditions as in Examples 1 to 12 and Comparative Examples 13 to 1B, and powder X-ray diffraction was also conducted. The ferromagnetic phase: R2Fe14B was identified and distinguished by ◎, 0 or The results are shown in Table 2.

From the results in Table 2, it can be seen that almost the same results as in Examples 1 to 12 and Comparative Example 13 to tC can be obtained even if the green compact of the mixed powder is directly dehydrogenated.

Examples 33-38 and Comparative Examples 39-42 Purity: 99
．． Mix 9% by weight of Nd powder, Pr powder, and Dy powder to prepare R powder having the composition shown in Table 3,
Further, purity: 99.9% by weight and particle size: 20
Fe2B powder below 0m, particle size as replacement powder:
A Co powder of 1 m or less and an electrolytic iron powder having a purity of 99.9% by weight and a particle size of BOOura or less were prepared and used as raw material powder.

These raw material powders were blended to have the composition (atomic percentage) shown in Table 3, and mixed in a ball mill to form a mixed powder with an average particle size of 40 uM.

When this mixed powder was subjected to powder X-ray diffraction and phase identification was performed, only the diffraction lines of R, Fe2B, Co, and Fe were observed.

This mixed powder was molded with a pressure crab of 4Ton/c- to form a green compact, heat-treated in hydrogen at 840°C and 1 atm, and then dehydrogenated to 860°C and 5 x 1O-2Torr. The mixture was cooled and crushed to obtain R-Fe-B permanent magnet powder. When R-Fe-B permanent magnet powder was produced from the above mixed powder, the yield was 97% or more in all cases.

The obtained R-Fe-B permanent magnet powder was measured for iHc at a magnetizing magnetic field of 40 koe using a vibrating magnetometer (VSM), and the results are shown in Table 3. Linear diffraction was performed to identify the ferromagnetic phase: R2Fe14B. The above powder X-ray diffraction results are as follows: ◎: Only the diffraction line of the ferromagnetic phase R2Fe14B is confirmed, and almost no diffraction lines of other phases are confirmed.○: The diffraction line of the ferromagnetic phase R2Fe14B is confirmed, and X, in which diffraction lines of other phases are also clearly observed, is classified as ◎, O, and X, and is shown in Table 3, with almost no diffraction lines of the ferromagnetic phase R2F 614 B being observed.

Furthermore, the obtained R-Fe-, B-based permanent magnet powder was mixed with an epoxy resin in an amount of Bffi%, and the pressure was set at 7To.
An isotropic bonded magnet was produced by molding with n/cd and heat curing at 120°C for 5 hours, and the magnetic properties of the bonded magnet were measured using a magnetization field of 40 kOc using a 0-mark magnetometer. The results are also shown in Table 3.

From the results in Table 3, it can be seen that the R powder produced in Examples 33 to 38 satisfies the conditions of this invention even when R powder is used as the raw material powder.
-Fe-B permanent magnet powder exhibits high coercive force, and bonded magnets made from this R-Fe-B permanent magnet powder also exhibit high magnetic properties. It can be seen that Comparative Examples 39 to 42, which deviate from the conditions of the invention, do not exhibit sufficient magnetic properties.

Examples 43-50 and Comparative Examples 51-52 Purity: 99
．． Nd hydride (N d
H, 3) Powder, purity: 99.9% by weight, particle size:
F e 2 B powder below 400 tng, and purity =
Electrolytic iron powder containing 99.9% by weight and particle size: 400 μs or less is prepared, and these powders are blended into the composition shown in Table 4, mixed in a ball mill, and have the average particle size shown in Table 4. It was made into a mixed powder. When this mixed powder was subjected to powder X-ray diffraction and a phase window was performed, N d H, Fe 2
Only the diffraction lines of 2.3 for B and Fe were observed.

This mixed powder was molded into a green compact using a pressure crab of 4 Ton/c-, and then heat-treated in hydrogen at 840°C and 1 atm, and then heated at 860°C and 5 x 1O-2 Torr.
Dehydrogenated to r, cooled, and crushed to produce Nd-Fe-B
A permanent magnet powder was obtained.

The obtained Nd-Fe-B permanent magnet powder was subjected to a magnetizing magnetic field of 40 kOe using a vibrating magnetometer (VSM).
The iHc was determined to be #1 and the results are shown in Table 4, and powder X-ray diffraction was performed to identify the ferromagnetic phase: Nd2Fe14B. The above powder X-ray diffraction results are as follows: ◎ indicates that only the diffraction line of the ferromagnetic phase Nd2F814B is confirmed, and almost no diffraction lines of other phases are confirmed; 0 indicates that the diffraction line of the ferromagnetic phase Nd2Fe14B is confirmed;
Diffraction lines of other phases are also clearly confirmed. × indicates the ferromagnetic phase N d 2 F? 14 B diffraction lines are hardly observed and are shown in Table 4, distinguished by ◎, 0, and X.

Furthermore, the obtained Nd-Fe-B permanent magnet powder was mixed with 3% by weight of epoxy resin,
/c molding and heat curing at 120°C for 5 hours to produce an isotropic bonded magnet. Using a self-recording magnetometer, the magnetic properties of the bonded magnet at a magnetizing magnetic field of 40 kOe were measured, and the results were are shown in Table 4.

From the results in Table 4, when the mixed powder has an average particle size of 0.5 to 100, Nd-Fe-B permanent magnet powder with a high coercive force is produced, and the bonded magnet produced using this powder also has a high coercive force. It can be seen that it exhibits magnetic properties.

Examples 53 to 55 and Comparative Examples 56 to 57 A mixed powder having the composition of Example 3 was molded at a pressure of 4 Ton/c to form a green compact, and this green compact was molded at a temperature of 2850°C and 250°C.
After heat treatment in Torr hydrogen, dehydrogenation was performed at a temperature of 850°C to the degree of vacuum shown in Table 5, cooled, and crushed to obtain R-Fe-B permanent magnet powder.

Regarding the obtained R-Fe-B permanent magnet powder, the iHc at the time of magnetizing magnetic field = 40 koe was measured using a vibrating magnetometer (VSM).
of epoxy resin and pressure crab 7Ton/c-
An isotropic bonded magnet was produced by molding and heat curing at a temperature of 120°C for 5 hours, and a magnetizing magnetic field of 4
The magnetic properties of the bonded magnet at 0 kOe were measured, and the results are shown in Table 5. The values marked with a square in Table 5 are values outside the conditions of the present invention.

By the production method of this invention, the degree of vacuum in dehydrogenation treatment is 1To
It can be seen that when R-Fe-B alloy powder is produced at the same time as rr or less, magnet powder with high coercive force is produced and exhibits high magnetic properties even when used in a bonded magnet.

Examples 58-8B Purity: 99. RH,, powder (where R is Nd
: 95% by weight, P": 5% by weight)
, Fe 2 B powder with purity 799.9% by weight and particle size: 400 tu@ or less, particle size: 100x as replacement powder
The following B powder, FeB powder, Fe 3C powder\AfI
Powder, S1 powder and FeGa powder, and purity: 9
Electrolytic iron powder containing 9.9% by weight and particle size: 400- or less was prepared, and these powders were blended to have the composition shown in Table 6, mixed in a ball mill, and average particle size: 30. I made it into a mixed powder. Powder X-ray diffraction of this mixed powder was performed, and phase window analysis revealed that RH2, t-Fe B, F
eB, B, Fe5C, Ag, Si.

Only FeGa and Fe diffraction lines were observed.

This mixed powder was molded into a green compact using a pressure crab of 4 Ton/cd, and then heat treated in hydrogen at 840°C and 1 atm, and then heated at 860°C and 10' Tor
It was dehydrogenated to r, cooled, and crushed to obtain R-Fe-B permanent magnet powder. When R-Fe-B permanent magnet powder was produced from the above mixed powder, the yield was 97% or more in all cases.

The obtained R-Fe-B permanent magnet powder was subjected to a magnetizing magnetic field of 40 kO using a vibrating magnetometer (VSM).
The iHc at time e was measured and the results are shown in Table 6. In addition, powder X-ray diffraction was performed to identify the ferromagnetic phase: R2Fe14B, and the diffraction lines of the ferromagnetic phase: R2Fe, 4B were confirmed. , diffraction lines of other phases were also confirmed.

The obtained R-Fe-B permanent magnet powder was mixed with 3% by weight of epoxy resin, molded with a pressure crab at 7Ton/cd, and heat-cured at 120°C for 5 hours to produce an isotropic bonded magnet. The magnetic properties of the bonded magnets were measured using a self-recording magnetometer at a magnetizing magnetic field of 40 kOe, and the results are also shown in Table 6.

From the results in Table 6, it is clear that even if part or all of Fe2B is replaced with B, FeB, or Fe5C, or if part of Fe is replaced with Ajl, St, or FeGa, a permanent magnet with high coercive force can be obtained. A powder is produced, in particular A, 1? , Sl
, it can be seen that in the case of FeGa substitution, the coercive force is further improved.

Examples 67 to 78 and Comparative Examples 79 to 84 The mixed powder having the composition of Example 3 was molded at a pressure of 4Ton/cd to form a green compact, and then heated at 300T from room temperature to the temperature shown in Table 7.
After heat treatment in a mixed atmosphere of hydrogen and Ar with orr hydrogen partial pressure, 5X lO'To
It is dehydrogenated to rr, cooled, and crushed to produce R-Fe-
B-based permanent magnet powder was obtained. The yield of magnet powder from mixed powder was all 96% or more.

Regarding the obtained magnet powder, IHC was measured at a magnetizing magnetic field of 40 kOe using a vibrating magnetometer (VSM), and the results are also shown in Table 7. In Table 7, brown marks indicate values outside the conditions of this invention.

From the results shown in Table 7, the heat treatment temperature in a mixed atmosphere of hydrogen gas and Ar gas is within the range of 500 to 1000°C, and the dehydrogenation temperature is also within the range of 500 to 1000°C.
It can be seen that by maintaining the temperature within the range of 0° C., R-Pa-B permanent magnet powder having a high coercive force can be produced.

In addition, in Comparative Examples 83 and 84, the green compact obtained from the mixed powder having the composition of Example 3 was heated from room temperature to 850'
The coercive force of RFe-B permanent magnet powder obtained by heat treatment in a hydrogen-free atmosphere up to C, further dehydrogenation treatment, and then crushing was determined by Ipj, but when no hydrogen is used at all in the heat treatment process. It can be seen that the coercive force of the permanent magnet powder is very low.

Examples 85 to 96 and Comparative Examples 97 to 98 The R-Fe-B permanent magnet powder obtained in Example 4 was further heated in an Ar gas atmosphere of 1 atm or in a vacuum of 2 x 1 G'Torr. Heat treatment was carried out at the temperature shown in the table for 10 to 120 minutes.

The obtained R-Fe-B permanent magnet powder was measured for iHc at a magnetizing magnetic field of 40 kOc using a vibrating magnetometer (VSM), and further, this magnet powder and 3% by weight
Mix with epoxy resin and press 7Ton/cj
An isotropic bonded magnet was prepared by molding and heat curing at a temperature of 120°C for 5 hours, and a magnetizing magnetic field of 4
The magnetic properties of the bonded magnet at 0 kOe were measured, and these n
The constant results are shown in Table 8. The values marked with a chestnut in Table 8 are values outside the conditions of the present invention.

From the results in Table 8, it can be seen that R-
It can be seen that it is better to further heat treat the Fe-B based permanent magnet powder. In that case, if the heat treatment temperature exceeds 1000°C, the coercive force of the magnet powder will decrease and the magnetic properties of the bonded magnet made using the magnet powder will also decrease.
In order to further improve the magnetic properties, heat treatment temperature: 300 to 100°C is required.
It can be seen that the temperature is preferably within the range of 0°C.

〔Effect of the invention〕

This invention uses a specific raw material powder and incorporates a hydrogen treatment method in a method for producing R-Fe-B permanent magnet powder, thereby preventing the powder from being oxidized (R-Fe-B).
At the same time as Fe-B alloying, magnet powder with high magnetic properties is produced.
It has stable properties and is manufactured very efficiently. Furthermore, the magnet powder obtained by the production method of the present invention is not only sufficiently practical for bonded magnets, but also can be used as raw material powder for sintered magnets. Furthermore, by utilizing hot plastic working, which is a conventional means of anisotropy, it is also possible to produce anisotropic magnets or anisotropic magnet powder, which has extremely high industrial value.

Claims (4)

[Claims] (1) R-Fe- mainly consists of at least one rare earth element including Y (hereinafter referred to as R), iron, and boron.
In the method for producing B-series permanent magnet powder, as raw material powder,
Prepare R hydride powder, ferroboron powder, and iron powder, and prepare these powders in atomic percentages such that R hydride powder: 10-30%, ferroboron powder: 3-30%, iron powder: balance. Average particle size obtained by blending and mixing: 0.5
The mixed powder of ~100 μm is heat treated at a temperature of 500 to 1000°C in a hydrogen gas atmosphere or a mixed atmosphere of hydrogen gas and inert gas, and then at a temperature of 500 to 1000°C and a hydrogen gas pressure of 1 Tor.
After dehydrogenating until it becomes a vacuum atmosphere of r or less or an inert gas atmosphere of hydrogen gas partial pressure: 1 Torr or less,
A method for producing rare earth-Fe-B permanent magnet powder, which comprises cooling. (2) In the manufacturing method of R-Fe-B permanent magnet powder mainly composed of R, iron, and boron, R hydride powder, ferroboron powder, and iron powder are prepared as raw material powders, and these powders are atomically In percentage terms, R hydride powder: 10-30%, ferroboron powder: 3-30%, iron powder: balance, average particle size obtained by blending and mixing: 0.5
~100μm mixed powder, temperature: 500~1000℃
Production of rare earth-Fe-B permanent magnet powder characterized by dehydrogenating until it becomes a vacuum atmosphere with a hydrogen gas pressure of 1 Torr or less or an inert gas atmosphere with a hydrogen gas partial pressure of 1 Torr or less, followed by cooling. Law. (3) In the method for producing R-Fe-B permanent magnet powder mainly composed of R, iron, and boron, R powder, ferroboron powder, and iron powder are prepared as raw material powders, and these powders are expressed in atomic percent as follows: R powder: 10
~30%, ferroboron powder: 3~30%, iron powder: balance, Average particle size obtained by blending and mixing: 0.5
The mixed powder of ~100 μm is heat treated at a temperature of 500 to 1000°C in a hydrogen gas atmosphere or a mixed atmosphere of hydrogen gas and inert gas, and then at a temperature of 500 to 1000°C and a hydrogen gas pressure of 1 Tor.
After dehydrogenating until it becomes a vacuum atmosphere of r or less or an inert gas atmosphere of hydrogen gas partial pressure: 1 Torr or less,
A method for producing rare earth-Fe-B permanent magnet powder, which comprises cooling. (4) After the above dehydrogenation treatment, temperature: 300-1000
4. The method for producing rare earth-Fe-B permanent magnet powder according to claim 1, 2 or 3, characterized in that the powder is heat-treated at <0>C and then cooled.