JPH04218903A - Manufacture of anisotropic rare earth magnet or anisotropic rare earth magnet powder - Google Patents

Abstract

PURPOSE:To provide anisotropic rare earth magnet or anisotropic rare earth magnet powder which has both high coercive force and high remaining flux density (that is, high maximum energy product). CONSTITUTION:Alloy powders (X) and (Y) manufactured by liquid quenching method are mixed. Here, alloy powder (X) is mainly composed of Nd, Fe(Co), B and has high remaining flux density after anisotropic processing, and alloy powder (Y), whereto Cu is added besides Nd, Fe(Co), B, attains high coercive force after anisotropic processing. After the mixed powder is formed by hot press, an anisotropic rare earth magnet is acquired by applying plastic deformation at a high temperature. Furthermore, the mixed powder is sealed in a metallic container and the container is hot-pressed; thereby, anisotropic rare earth magnet powder can be acquired.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a method for producing an anisotropic rare earth magnet or anisotropic rare earth magnet powder having an R2 Fe14B compound (where R is a rare earth element containing at least one of Nd or Pr) as a main phase. It is related to. The magnet or magnet powder obtained by the present invention can be used in a wide range of various actuators such as small motors because it can have high performance and low cost.

0002

[Prior art] Rare earth element R and representative transition metal element Fe
A quenched ribbon having excellent magnetic properties can be obtained by ultra-quenching a molten alloy containing B and B in a ratio of close to 2:14:1 by a liquid quenching method such as a single roll method (U.S. Pat. No. 4,802,931). No. specification, JP-A-59-647
39, JP-A-60-9852). This quenched ribbon is almost magnetically isotropic.

[0003] The powder obtained by crushing the quenched ribbon of the Nd-Fe-B alloy described above is compressed into a bulk material in a state close to the true density of the alloy by hot compression molding (hot pressing). I can do it. This is disclosed in U.S. Pat. W
．． Paper presented by Lee “Hot-pressed
odymium-iron-boron magnet
ts” (Applied Physics Let
ters, Vol. 46, No. 8, pp790-79
1, April 15, 1985). The residual magnetic flux density of the above hot compression molded product is approximately 8kG.
It is known as a conventional technique that the value of .

[0004] In order to obtain a higher residual magnetic flux density, it is necessary to impart anisotropy to the magnet. The above R. W. Lee proposes an anisotropy method using plastic deformation. This method is
After increasing the density of a compression molded body of Nd-Fe-B alloy powder to a density close to the true density of the alloy by hot pressing, the compact is again subjected to upsetting processing (Die-Ups).
et) to apply plastic deformation. 8 to 13 depending on the degree of upsetting or alloy composition.
It has been reported that a residual magnetic flux density of kG can be obtained (
For example, Y. Nozawa et al., J. Appl. Phys.
．． , Vol. 64, No. 10, pp5285-528
9 November 15, 1988).

However, in the Nd-Fe-B ternary system, even if the residual magnetic flux density is improved by upsetting, the coercive force is reduced, causing a problem in thermal stability. On the other hand, it has been reported that by adding Ga, the coercive force can be increased and the thermal stability can be improved (Japanese Unexamined Patent Publication No. 7504/1983). In addition, the present applicant has previously developed an R-
As a method for producing Fe-B-based anisotropic powder, the above-mentioned isotropic quenched ribbon (or powder obtained by crushing it) is packed in a metal container and hot rolled together with the container. The method was filed (Japanese Patent Application No. 1-202675). In this application, it was disclosed that by adding a small amount of Cu, the coercive force of the anisotropic powder is significantly improved and the thermal stability of a magnet molded using the anisotropic powder is improved. Cu addition is
The above upsetting process also brings about an increase in coercive force.

[0006]

[Problems to be Solved by the Invention] The present invention is directed to
An object of the present invention is to provide a method for producing a rare earth magnet or rare earth magnet powder that simultaneously improves the coercive force and residual magnetic flux density (i.e., maximum energy product) of a B-based anisotropic magnet.

[0007]

[Means for Solving the Problems] The gist of the present invention is as follows. (1) R of 12% or more and 20% or less in atomic percentage (R is a rare earth element containing at least one of Nd or Pr)
, B of 4% or more and 8% or less, C of 0.05% or more and 2% or less
In the method for manufacturing an anisotropic rare earth magnet, the balance is Fe and unavoidable impurities.
, and the balance consists of Fe and unavoidable impurities (X), R of 12% to 20%, B of 4% to 8%, B of 0.2% to 8%, also produced by the liquid quenching method. After obtaining a mixture of the following Cu and an alloy powder (Y) with the balance consisting of Fe and unavoidable impurities such that the volume percentage of the alloy powder (Y) is 5% or more and 50% or less, A method for producing an anisotropic rare earth magnet, which comprises densifying the mixture by hot compression molding and then applying plastic deformation. (2) The method of applying plastic deformation is 600% by electrical heating.
The preceding item is characterized in that it is a method of applying a first stage of plastic deformation by heating to a temperature of 800 °C or higher and lower than 800 °C, and then applying a second stage of plastic deformation by heating to a temperature of 800 °C or higher and 1000 °C or lower. 1. The method for manufacturing an anisotropic rare earth magnet according to 1. (3) R of 12% or more and 20% or less in atomic percentage (however, R is a rare earth element containing at least one of Nd or Pr)
, B of 4% or more and 8% or less, C of 0.05% or more and 2% or less
In a method for producing an anisotropic rare earth magnet powder consisting of u, and the balance being Fe and unavoidable impurities, R of 12% to 20%, B of 4% to 8%, and the balance produced by a liquid quenching method. Alloy powder (X) consisting of Fe and unavoidable impurities and 12% alloy powder also made by liquid quenching method
R of 20% or more, B of 4% or more and 8% or less, 0.2%
A mixture of 8% or less Cu and an alloy powder (Y) with the balance consisting of Fe and unavoidable impurities was mixed to obtain a mixture in which the volume percentage of the alloy powder (Y) was 5% or more and 50% or less. Afterwards, the mixture was sealed in a metal container and heated for 50 minutes.
A method for producing anisotropic rare earth magnet powder, comprising rolling the container at a temperature of 0°C or higher and 900°C or lower. (4) The method for producing an anisotropic rare earth magnet or anisotropic rare earth magnet powder according to item 1 or 3 above, characterized in that up to 20% of the amount of Fe is replaced with Co.

[0008]

[Operation] The present invention provides two types of alloy powders (X) with different compositions.
(Y) and hot compression molding followed by plastic deformation at a high temperature to produce an anisotropic rare earth magnet, or by sealing the mixed powder in a metal container and heating it at a temperature of 500°C or more and 900°C or less. The main idea is to produce anisotropic rare earth magnet powder by hot rolling the container at a high temperature. The purpose of performing plastic working or rolling is to impart anisotropy to the magnet or magnet powder in order to obtain a higher residual magnetic flux density.

[0009] Here, the alloy powder (X) is an alloy powder made by a liquid quenching method and consisting of 12% to 20% R, 4% to 8% B, and the balance being Fe and inevitable impurities. . In the case of the Nd-Fe-B ternary system, if it is plastically deformed at high temperature to make it anisotropic, a high residual magnetic flux density can be obtained, but at the same time, the coercive force is greatly reduced. This poses a practical problem in terms of thermal stability.

On the other hand, the alloy powder (Y) was prepared by a liquid quenching method and contained R of 12% to 20%, B of 4% to 8%,
It is an alloy powder consisting of 0.2% or more and 8% or less of Cu, and the balance is Fe and unavoidable impurities. In the case of the Nd-Fe-B-Cu system to which Cu is added, a high coercive force can be obtained after anisotropy due to plastic deformation. however,
Nd-Fe-
It has been found from research by the present inventors that the residual magnetic flux density is lower than that of the B ternary system.

In the manufacturing method of the present invention, an alloy powder (Y) capable of imparting a high coercive force is added to an alloy powder (X) capable of obtaining a high residual magnetic flux density, and after mixing, the alloy powder (Y) is hot-pressed. It is characterized by molding and applying plastic deformation at high temperatures, or by sealing the mixed powder in a metal container and hot rolling the container. The anisotropic rare earth magnet or anisotropic rare earth magnet powder obtained in this way has a content of 12% or more.
% or less R, 4% or more and 8% or less B, 0.05% or more2
% or less of Cu, and the balance consists of Fe and unavoidable impurities, and has both high coercive force and high residual magnetic flux density (therefore, high maximum energy product).

The details of the present invention will be explained below. Although Nd is most preferred as the rare earth element R, it is also possible to replace part or all of Nd with Pr. Here, the amount of R in the powders (X) and (Y) is limited to 12% or more and 20% or less. When the amount of R is less than 12%, the deformability of the powder is extremely reduced and sufficient anisotropy cannot be achieved. Further, when the amount of R is more than 20%, the residual magnetic flux density is low. A portion of the rare earth element R can be Dy within a range not exceeding 20% of the total R. In particular, by incorporating Dy into the alloy powder (Y), it is possible to minimize the decrease in the residual magnetic flux density of the magnet and increase the coercive force. Here, if the content of Dy exceeds 20% of the total R, the decrease in residual magnetic flux density cannot be ignored.

[0013] When the amount of B is less than 4%, a large amount of R2 Fe1
Seven phases appear, and when it exceeds 8%, many B-rich phases appear. Both phases inhibit plastic deformation at high temperatures for anisotropy. Therefore, B in the quenched ribbon and the magnet or magnet powder solidified thereof according to the present invention.
The amount is uniformly limited to 4% or more and 8% or less. Cu is
It is added as a component of alloy powder (Y). Here, Cu is concentrated in the R-rich phase existing at grain boundaries. R-
The melting point of the rich phase is lowered by about 200°C. In the Nd-Fe-B-Cu system in equilibrium, the melting point of the R-rich phase is 490°C. Therefore, during hot compression molding near 700°C and plastic deformation at high temperatures, R
- The rich phase becomes a melt and oozes out. By oozing out, Cu spreads throughout the molded body and increases the coercive force of the molded magnet, particularly by increasing the coercive force at the powder interface. The amount of Cu added is limited to 0.2% or more and 8% or less. If it is less than 0.2%, it will not contribute to improving the coercive force of the molded magnet, and if it exceeds 8%, the reduction in the residual magnetic flux density of the molded magnet cannot be ignored.

The volume percentage of powder (Y) in the mixture of powders (X) and (Y) is limited to 5% or more and 50% or less. The reason is as follows. If the volume percentage of the additive powder (Y) is less than 5%, a sufficiently high coercive force cannot be obtained. Furthermore, if the volume percentage of (Y) exceeds 50%, a high residual magnetic flux density cannot be obtained. Powder (X) and (Y)
The average amount of Cu in a magnet formed by molding a mixture of
．． It is limited to 0.5% or more and 2% or less. In order to simultaneously obtain high coercive force and high residual magnetic flux density, a more preferable composition range of Cu is 0.1% or more and 1% or less.

[0015] In order to raise the Curie temperature of the alloy and reduce the temperature change in magnetic flux density at the operating temperature, a part of Fe may be replaced with Co. Also in the present invention, up to 20% of the amount of Fe can be replaced with Co without impairing the magnetic properties. The ultra-quenched alloy powder having the above-mentioned limiting components is most stably obtained by the known single roll method, but it can also be obtained by other twin roll methods or gas atomization methods. In the present invention, it is necessary to mix two types of alloy powders in an appropriate ratio, which can be easily done using, for example, a V-type mixer.

When producing an anisotropic rare earth magnet, the mixed powder is hot compression molded and then plastically deformed at high temperature. Hot compression molding of the above mixed powder is easy using a hot press machine with a normal mold heating method or an electric sintering machine capable of electric heating at a sample heating temperature of 600 to 800°C and a pressing force of 200 to 1000 kg/cm2. can be done. The process of applying plastic deformation to the molded body can be performed using a hot press machine or an electric sintering machine, similar to hot compression molding.

[0017] Here, after plastic deformation, it is desirable that a magnet with a predetermined shape be obtained and that post-processing such as polishing is not required. This so-called Net-Shape
) It is effective to use an electric sintering machine to perform the forming. The reason for this is explained below. The current heating method has a very fast response to heating temperature over time, and is capable of rapid heating and cooling. That is, if an electric sintering machine is used, processing at high temperatures and in a short time becomes possible. Furthermore, after processing at a certain temperature, the material can be rapidly heated or cooled and subsequently processed at a different temperature.

[0018] The above plastic deformation can be carried out at a temperature of 600°C or higher, but it is preferably carried out at a temperature of lower than 800°C in order to suppress the growth of crystal grains and prevent deterioration of coercive force and thermal stability. However, the present inventors have found that in order to perform net shape molding, the heating temperature of the molded body to be processed must be 800° C. or higher. This is because the ductility of the molded product is not sufficiently high below 800° C., and the shape of the molded product after processing (particularly the corners) is not determined.

If an electric current sintering machine is used here, the following two-stage processing can be performed in order to perform plastic processing and net shape forming at the same time. That is, the pressing force is 200 to 1000 kg/
cm2, the temperature of the molded body was increased to 600 in the first stage.
Most of the predetermined plastic working is performed while maintaining the temperature at a temperature of .degree. C. or more and less than 800.degree. In the second stage, the current is increased to over 800℃1
The shape of corners etc. is determined by rapid heating to a temperature of 000°C or less and further plastic working. This second stage treatment can be completed in a short time (5 to 60 seconds) by using electrical heating. That is, the molded body is exposed to a high temperature of 800° C. or higher for a short period of time. For this reason, the growth of crystal grains is minimized, and there is little deterioration in magnetic properties. On the other hand, in a mold heating type hot press machine, the response of heating and cooling temperature is slow, so it takes 5 to 30 minutes to perform the above-mentioned second stage treatment, and deterioration of magnetic properties cannot be avoided.

[0020] Furthermore, when performing plastic deformation and net shape forming as described above, it is essential to use alloy powder to which Cu is added as a raw material. The reason is as follows. According to the findings of the present inventors, Cu-added alloy powder or powder mixed with this powder can suppress crystal grain growth and maintain high coercive force even when processed at high temperatures of 800°C or higher. . Therefore, even if the two-step processing described above is performed, the magnetic properties do not deteriorate much. On the other hand, in the case of a single Nd-Fe-B ternary powder to which Cu is not added, the coercive force is extremely reduced by this two-step processing.

[0021] When producing anisotropic rare earth magnet powder,
The mixed powder is hot rolled. Hot rolling of the mixed powder is performed as follows. The mixed powder is packed into a metal container, the inside of the container is replaced with a vacuum or an inert atmosphere and sealed, and then the container is rolled at a temperature of 500° C. or more and 900° C. or less. The purpose of packing the powder in a metal container is to provide restraint to the powder against external stress for plastic deformation. Furthermore, since this alloy is very easily oxidized, the atmosphere must be a vacuum or an inert atmosphere when the temperature is raised. If the rolling temperature is lower than 500°C, the deformability of the powder will be extremely reduced and sufficient anisotropy cannot be achieved.
If the temperature is higher than 900°C, the crystal grains become coarse and the coercive force decreases, so the temperature was set in the range of 500°C or more and 900°C or less. In order to obtain an anisotropic powder with high magnetic properties, it is necessary to perform rolling so that the powder itself is subjected to a reduction of 40% or more.

[0022] Anisotropic rare earth magnets obtained by the rolling method can be completely made into bulk, but usually include magnets of various sizes. Therefore, in order to make the particle size uniform, it can be pulverized using a disc mill, Brown mill, pin mill, ball mill, attritor mill, or the like. In this way, anisotropic rare earth magnet powder is obtained.

[0023]

[Example] Example 1 Fe-14%Nd-6%B (Nd14Fe
80B6) alloy powder (X) with a composition of Fe-14%N
d-5%B-1%Cu (Nd14Fe80B5 Cu1
) was prepared. To produce these powders, an alloy having the above composition was first melted by high-frequency induction heating, and the molten metal was injected onto the surface of a rotating copper roll from a quartz nozzle having a hole with a diameter of 1 mm. The surface speed of the roll at this time was 25 m/sec,
This is the optimum rapid cooling condition for obtaining fine crystal grains. The obtained ribbon was pulverized to 250 μm or less. Powder (X) and (
Y) were mixed in various proportions, and the mixed powder was first hot compression molded using an electric sintering machine, and then plastically deformed by upsetting. In this experiment, the molded body was shaped like a ring.

First, by hot compression molding, the outer diameter was 14.1 m.
A ring-shaped molded body having an inner diameter of 8.5 mm and a thickness of 3.4 mm was obtained. The next upsetting process was to use a ceramic die with a cylindrical cavity with a diameter of 19 mm and an outer diameter of 19 mm.
m, the molded body was set in a set consisting of a cylindrical carbon punch with an inner diameter of 8.5 mm and a stainless steel core with a diameter of 8.5 mm, and with a pressure of 450 kg/cm2 applied to the molded body, a current of 750 A was applied. The molded body was heated. Under the above pressure and current, the actual temperature of the sample was 700~7
The deformation ended when the temperature reached 50°C, and the time required from the start of heating to the end of the deformation was about 3 minutes. The obtained molded body has an outer diameter of 19 mm, an inner diameter of 8.5 mm, and a thickness of 1.5 mm.
It has a ring shape, and the thickness reduction rate due to deformation is 56%.

This molded body was subjected to pulse magnetization of 60 kOe in the pressing direction, and its magnetic properties were measured using a self-recording magnetometer. FIG. 1 shows the magnetic properties of the compact in the pressing direction with respect to the mixing ratio of powder (Y). As the mixing ratio of powder (Y) increases, the coercive force iHc increases rapidly, becomes constant at a mixing ratio of 30% or more, and the maximum energy product (BH) ma
x is maximum at 20-40% mixing. This is a synergistic effect of the high residual magnetic flux density of the powder (X) and the high coercive force of the Cu-added powder (Y).

For comparison, the same figure shows the magnetic properties of magnets similarly produced using single powders having Cu concentrations corresponding to the respective mixed powders. It can be seen that a single powder cannot provide the same high properties as the mixed powder. Example 2 Powder (X) and (Y) with the same composition as Example 1 were combined into powder (Y)
The mixture was mixed so that the ratio was 30%, and hot compression molding was performed in the same manner as in Example 1. Plastic deformation is achieved by upsetting.
It went like this: The molded body was set in the same die set as in Example 1. While applying a pressure of 300 kg/cm 2 to the molded body, the molded body was heated by applying a current of 550 A. Under this pressure and current, the temperature of the compact reached a maximum of 750° C. after about 6 minutes, and most of the plastic deformation had occurred by then. In this example, when the temperature reached 750°C, the current was further increased to 800A, and the molded body was heated for 30 seconds under the same pressure. The maximum temperature reached in this second stage of heating is 900.
It was ℃. The molded product obtained by this two-step heating deformation was a ring shape with an outer diameter of 19 mm, an inner diameter of 8.5 mm, and a thickness of 1.5 mm with well-protruded edges, and no machining was required to obtain the dimensions. .

Table 1 shows its magnetic properties. In the case of mixed powders, high coercive force and high residual magnetic flux density (and therefore high maximum energy product) are simultaneously obtained.

[0028]

[Table 1]

Example 3 Fe-7.5%Co-14%Nd-6%B in atomic percentage
Alloy powder (X1) with a composition of (Nd14Fe72.5Co7.5 B6) and Fe-11%Co-14%Nd-6
%B(Nd14Fe69Co11B6) alloy powder (X2) and Fe-14%Nd-5%B-1%Cu(
An alloy powder (Y) having a composition of Nd14Fe80B5 Cu1 ) was produced in the same manner as in Example 1.

Powder (X1) and (Y) and (X2) and (Y
) were mixed so that the ratio of powder (Y) was 30%, and the mixed powder was first hot compression molded using an electric sintering machine, and then subjected to plastic deformation by upsetting. The initial hot compression molding yielded a disc-shaped molded product with a diameter of 20 mm and a thickness of about 6 mm.

In the next upsetting process, this molded body was placed in the cavity of a ceramic die having a cylindrical cavity with a diameter of 36 mm, and a weight of 450 kg/cm2 was applied to the molded body.
The molded body was heated by applying a current of 1800 A while applying a pressure of . Under the above pressure and current, plastic deformation ends when the measured temperature of the sample reaches 700 to 750°C.
The time required from the start of heating to the end of deformation was 4 to 5 minutes. The average thickness of the obtained molded body was 2.4 mm, and the rate of decrease in thickness due to deformation was 60%.

The magnetic properties in the pressing direction are shown in Table 2 together with the Curie temperature. For comparison, the characteristics when the powders (X1) and (X2) were molded as a single product and similarly upset were also shown. In the case of the Nd-Fe-B ternary system, the Curie temperature is 31
The temperature is 5°C. C in both single powder and mixed powder
The addition of o increases the Curie temperature. Also, (X1
) and (X2), a high residual magnetic flux density can be obtained by mixing the powder (Y), and the coercive force can be significantly improved.

[0033]

[Table 2]

Example 4 Fe-14%Nd-6%B (Nd14Fe
80B6) alloy powder (X) with a composition of Fe-14.4
%Nd-1.6%Dy-5%B-1.5%Cu((Nd
0.9 Dy0.1) 16Fe77.5B5 Cu1.
An alloy powder (Y) having the composition of 5) was prepared in the same manner as in Example 1.

Powders (X) and (Y) were mixed so that the ratio of powder (Y) was 30%, and hot compression molding and upsetting were performed in the same manner as in Example 3. Table 3 shows the magnetic properties in the pressing direction. A significant improvement in coercive force can be seen by mixing powder Y to which Dy and Cu are added. This greatly improves thermal stability.

[0036]

[Table 3]

Example 5 Powders (X) and (Y) having the same composition as in Example 1 were combined into powder (Y).
The mixture was mixed at a ratio of 30% and inserted into an iron pipe. Thereafter, the pressure inside the container was reduced to 10-3 to 10-4 and the container was sealed. This was rolled at 700° C. so that the rolling ratio of the contents was 80%. After rolling, it was water cooled.

[0038] The rolled contents are plate-shaped. A sample for magnetic measurement was obtained by overlapping and adhesive molding. After magnetization at 60 kOe, the magnetism was measured using a flux meter. Table 4 shows the results of magnetic measurements. As a comparative example, single powder (X), (Y) and Cu concentration 0.3a
The case of a single powder (Z) of t% is also shown. In the case of the present invention example obtained by mixing powders, high coercive force and high residual magnetic flux density can be obtained at the same time.

[0039]

[Table 4]

[0040]

[Effects of the Invention] In the method for manufacturing an anisotropic rare earth magnet according to the present invention, after mixing Nd-Fe-B alloy powders (X) and (Y) produced by a liquid quenching method, the mixture is subjected to plastic deformation. It is characterized by adding. Here, the alloy powder (X) is N
The main components are d, Fe(Co), and B, and the residual magnetic flux density after anisotropy is high, but the coercive force is low. On the other hand, alloy powder (Y)
Cu is added in addition to Nd, Fe(Co), and B, and a high coercive force can be achieved after anisotropy, but the residual magnetic flux density is low.

By mixing these powders, an anisotropic rare earth magnet or anisotropic rare earth magnet powder having both a high coercive force and a high residual magnetic flux density (therefore, a high maximum energy product) can be obtained after anisotropy by plastic deformation. be able to.

[Brief explanation of the drawing]

[Figure 1] Regarding an anisotropic rare earth magnet produced by mixing alloy powder (X) (Nd14Fe80B6) and alloy powder (Y) (Nd14Fe80B5 Cu1), and performing hot compression molding and upsetting, the difference between additive powder (Y) and It is a figure which shows the magnetic characteristic of a molded magnet with respect to a mixing ratio.

Claims (4)

[Claims] Claim 1: R of 12% to 20% in atomic percentage (R is a rare earth element containing at least one of Nd or Pr), B of 4% to 8%, 0.05% to 2
% or less of Cu, and the balance is Fe and unavoidable impurities.
% or less of B, and the balance is Fe and unavoidable impurities (X), 12% or more and 20% or less of R, 4% or more and 8% or less of B, and 0
．． A mixture of 2% or more and 8% of Cu and an alloy powder (Y) with the balance consisting of Fe and unavoidable impurities such that the volume percentage of the alloy powder (Y) is 5% or more and 50% or less. 1. A method for producing an anisotropic rare earth magnet, which comprises: obtaining a magnet, densifying the mixture by hot compression molding, and then applying plastic deformation. 2. A method of applying plastic deformation is to apply a first stage of plastic deformation by heating to a temperature of 600°C or more and less than 800°C by electrical heating, and then apply a first step of plastic deformation to a temperature of 800°C or more and less than 800°C.
2. The method for manufacturing an anisotropic rare earth magnet according to claim 1, wherein the second step of plastic deformation is performed by heating to a temperature of: 3. R in an atomic percentage of 12% or more and 20% (however, R is a rare earth element containing at least one of Nd or Pr), B of 4% or more and 8% or less, and 0.05% or more2
% or less of Cu, and the balance is Fe and unavoidable impurities. and alloy powder (X) with the balance consisting of Fe and unavoidable impurities, R of 12% to 20%, and B of 4% to 8%, also produced by the liquid quenching method.
, 0.2% or more and 8% or less of Cu, and an alloy powder (Y) with the balance consisting of Fe and unavoidable impurities,
After obtaining a mixture in which the volume percentage of the alloy powder (Y) is 5% or more and 50% or less, the mixture is sealed in a metal container and the container is rolled at a temperature of 500°C or more and 900°C or less. A method for producing anisotropic rare earth magnet powder characterized by: 4. The method for producing an anisotropic rare earth magnet or anisotropic rare earth magnet powder according to claim 1 or 3, characterized in that up to 20% of the amount of Fe is replaced with Co.