JPH08264308A - Rare earth magnet and its manufacture - Google Patents

Abstract

PURPOSE: To provide a manufacturing method of a highly efficient R-Fe-B rare earth magnet, which is in specific compositional region and has the R-Fe- Ga-Al phase as a constituent phase, and a rare earth magnet which is formed by conducting hot rolling a cast ingot and also by conducting a heat treatment. CONSTITUTION: The subject manufacturing method contains the method for manufacture of rare earth magnet consisting of Pr, Fe, B, Ca and Al, containing Pr of 15.0 to 17.5atom%, Ga of 0.1 to 0.8atom%, B of 4.8atom% or more, and the remaining Fe quantity of positive value and having a Pr-Fe-Ga-Al phase, a rare earth magnet on which Nd and Dy are partially substituted, and a magnet formed by conducting a hot rolling method. In the magnet having the above- mentioned composition and compositional phase, high magnetic characteristics, especially high coercive force, can be obtained. Accordingly, the advantages of the rare earth magnet formed by a hot rolling method, in which excellent mechanical strength can be obtained, can be promoted.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to rare earth-Fe-B-G.
The present invention relates to an a-Al rare earth magnet and a method for producing the rare earth magnet, in which an alloy ingot is subjected to hot rolling and then heat treatment.

[0002]

2. Description of the Related Art As a high-performance magnet containing Ga in the R-Fe-B system (where R represents a rare earth element), first, page 3, column 3, line 2 of JP-A-6-104108. Page 3, column 4 3
The coercive force iHc is 2 in the composition range described in the 9th line.
It is disclosed that a sintered magnet having a maximum magnetic energy product (BH) max of 0 kOe or more and 30 MGOe or more can be obtained. Also, page 2, column 2, 33-4 of JP-A-6-231921.
In the composition range as described in the first line, coercive force
iHc is 12 kOe or more, maximum energy product (BH) ma
A sintered magnet in which x is 42 MGOe or more is disclosed.

Even in a magnet manufactured by a method of hot working a cast ingot (casting / hot working method), G
The magnetic characteristics are improved by adding a. Japanese Patent Laid-Open No. 4-
As shown in page 3, right lower column, lines 2 to 15 of Japanese Patent No. 105305, one or more rare earth elements selected from Pr and Nd: 29 to 34% by weight in total, B: 0.8 to 1 0.0 wt%, one or more elements selected from the group consisting of Ga, In, and Sn: 0.2 to 0.8 wt% in total, balance: Fe and inevitable impurities, and rare earth-Fe-B First phase of the system and rare earth element- (Ga, In, S
A rare earth magnet characterized in that it has a structure composed of a n) type low melting point phase is disclosed. As shown in Table 4 on the lower left of page 8, iHc is approximately 16 kOe, (BH) m.
The magnetic characteristics of ax of approximately 32 MGOe are obtained. Further, as disclosed in JP-A-6-251917, page 3, lines 27-40, the alloy composition has an atomic ratio of R _x Fe _y B _z Ga.
When expressed as _100-xyz , x ≧ 15, y-14z>
Disclosed is a rare earth magnet having a composition range of 0, z ≧ 4, 100−x−y−z <2 and having an R ₆ Fe ₁₁ Ga ₃ phase in the magnet structure.

[0004]

In the sintered magnet containing Ga, high magnetic characteristics can be achieved as described above. However, the sintered magnet is described in Reference 1 (A. Arai et.al J
As shown in ournal of Applied Physics vol.75 No.10 p6631), it generally has a drawback of low mechanical strength. In particular, in a magnet in which the volume ratio of the main phase 2-14-1 phase is increased as much as possible to improve the magnetic characteristics, the feature of low strength becomes remarkable, and cracks are significantly generated. Further, it has a drawback that it is difficult to manufacture a large-sized magnet due to a manufacturing limitation such as a sintering method.

On the other hand, in the rare earth magnet produced by hot-rolling a cast ingot, the tensile strength is about three times that of the sintered magnet, as described in the above document 1. Have strength. Further, since it is produced by the hot rolling method, the first and second aspects of JP-A-5-315118 are claimed.
As described in 1), it is excellent in manufacturing large magnets, and the manufacturing process can be greatly simplified. In the case of magnets manufactured by the casting / hot working method, the magnets can be manufactured without passing through the powder process until the final step of the cast ingot, so that the voids found in sintered magnets are virtually eliminated. Not included. Further, since the amount of the R-rich phase, which is relatively ductile, is larger than that of the sintered magnet, high strength can be obtained.

As in the above-mentioned Japanese Patent Laid-Open No. 4-105305, it is possible to achieve both high coercive force and maximum energy product in a composition prepared by casting and hot rolling and added with Ga. However, as a result of further detailed studies on the composition of the Ga-added alloy, the coercive force deteriorates depending on the addition amount of each element and the balance of the composition even in the composition range specified by the specification of the publication. It became clear that it would happen. Further, in that case, as a structure necessary for improving the coercive force, Japanese Patent Laid-Open No. 4-105305 discloses that the structure is obtained when a rare-earth-Ga low melting point phase is present as the second phase in addition to the first phase. It has been found that even when such a second phase is present, the magnetic properties, particularly the coercive force, may be significantly reduced.

Even in the composition range defined in JP-A-6-251917, high characteristics may not be obtained in some cases. First, the amount of rare earth elements is 15 atomic% or more, but if the amount of rare earth elements is too large, the energy product deteriorates due to a decrease in the main phase amount and the corrosion resistance decreases due to an increase in the R-rich phase. Such problems occur. Regarding the amount of B,
If the B content is small even within the specified composition range (4 atom% or more), R ₂ which is a soft magnetic phase as a grain boundary phase
The Fe ₁₇ phase appears, which causes deterioration of magnetic characteristics.

The present invention provides an R-Fe-B rare earth magnet by a casting / hot rolling method, which has the advantages of solving the above-mentioned conventional problems and being excellent in mechanical strength and capable of producing a large magnet. The first purpose is to obtain high magnetic characteristics, especially high coercive force. The present invention also uses a part of Pr as D
The second purpose is to further increase the coercive force by substituting with y. A third object of the present invention is to provide a method for manufacturing a high-performance magnet by optimizing the heat treatment temperature.

[0009]

In order to achieve the above object, the rare earth magnet of the present invention comprises Pr, Fe, B, Ga and A.
1 and impurities unavoidable in production, Pr is 15.0
˜17.5 atomic%, Ga 0.1 to 0.8 atomic%, B content 4.8 atomic% or more, and residual Fe content (A atomic% value of Fe multiplied by 14 atomic% value) The numerical value obtained by subtracting the value is a positive value, and the magnet structure has a Pr—Fe—Ga—Al phase.

In the rare earth magnet of the present invention, a part of Pr is replaced with Nd, and (Pr, Nd) -Fe is contained in the magnet structure.
It has a -Ga-Al phase.

Further, in the rare earth magnet of the present invention, 10% or less of the Pr amount is replaced by Dy, and (Pr,
It has a Dy) -Fe-Ga-Al phase. More preferably, the Dy substitution amount is set to P
The amount of r is 4 to 10%.

Further, in the method for producing a rare earth magnet of the present invention, an alloy is melted and cast to produce an ingot, and the ingot is encapsulated in a metal capsule and hot-rolled at a temperature of 800 to 1100 ° C. The heat treatment is then performed at a temperature of 900 to 1050 ° C.

Further, the method for producing a rare earth magnet of the present invention comprises melting and casting an alloy to produce an ingot, encapsulating the ingot in a metal capsule, and then hot rolling at a temperature of 800 to 1100 ° C., After that, heat treatment is performed at a temperature of 900 to 1050 ° C, and further heat treatment is performed at a temperature range of 450 to 600 ° C.

[0014]

First, the reasons for limiting the alloy composition range of the present invention will be described. As the main rare earth element, the main phase is 2-14-1
From the phase potential, Pr and Nd are preferable,
When casting and hot rolling, it is preferable to mainly use Pr in order to obtain high coercive force while ensuring hot workability. The optimum composition range of such rare earth elements is preferably in the range of 15 atom% to 17.5 atom%. This is because in the composition range of less than 15 atomic%, cracks that occur during hot working are severe and the yield of magnet products deteriorates, resulting in a significant increase in cost. Further, when the addition amount is more than 17.5 at%, the volume ratio of the main phase is decreased and the magnetic properties are significantly deteriorated due to the deterioration of squareness, and R-Fe-Ga described later is produced.
-Al phase (where R is Pr, N in the present invention)
It is difficult to stably generate (d and Dy, which are collectively represented for convenience) in the grain boundary phase.

Regarding the amount of B, first, when the addition amount is less than 4.8 atomic%, R ₂ Fe which is a soft magnetic phase in the magnet structure is present.
The presence of ₁₇ phases becomes noticeable, resulting in deterioration of coercive force and squareness. Regarding the upper limit of the amount of B, the condition is that the numerical value of 14 times the atomic% is lower than the numerical value of Fe atomic% in the magnet. Here, the description of the amount of residual Fe is given in claim 1, and this amount is represented by the following formula.

[Remaining Fe content] = [atomic% of Fe in alloy]
Value] −14 × [atomic% value of B in alloy] That is, the amount of B increases and the residual Fe represented by the above formula
In the case of a magnet with a negative amount, R-
The Fe-Ga-Al phase does not exist, resulting in a low coercive force.

With respect to the amount of Ga added, the effect of increasing the coercive force is clearly seen as compared with the ternary system by adding 0.1 atom%. However, when the added amount exceeds 0.8 atomic%, the coercive force gradually decreases, and the magnetic potential decreases remarkably due to the increased Ga added amount, so that the effect of Ga added disappears.

Al is an essential element for forming the R-Fe-Ga-Al phase. The amount of Al added is not limited in the claims of the present invention, but if the amount added is large, the magnetization is lowered. Therefore, it is preferably 0.5 atomic% or less. When ferroboron containing Al is used as a raw material for the alloy, Al contained in ferroboron is effectively added as an alloying element. The amount of Al in the alloy thus produced is 0.5 atom% as described above.
It will fall within the following preferable range.

Next, R in the magnet structure according to claim 1
The -Fe-Ga-Al phase and its effect will be described. In the above-mentioned Japanese Patent Laid-Open No. 6-251917, R ₆ is contained in the magnet structure.
It is described that high magnet characteristics can be obtained when the Fe ₁₁ Ga ₃ phase is included, but as a result of detailed composition optimization experiments performed thereafter, it was found that a magnet structure not necessarily including the R ₆ Fe ₁₁ Ga ₃ phase was R- It was found that high characteristics can be obtained when the phase composed of the Fe-Ga-Al quaternary system exists between the main phase particles. Although the crystal structure and composition formula of this quaternary phase are not clear yet, in the example of analyzing the structure of the magnet in which high coercive force is obtained by EPMA as shown in Example 1, Pr: 34.5 Atomic%, Fe: 59.8 atomic%, G
The phase had a composition of a: 5.2 atomic% and Al: 0.5 atomic%. As a phase diagram study on the phase of the R-Fe-Ga ternary system, reference 2 (F. Weitzer el al; J. Le.
ss-Common Met. 167 (1990) 135), in which the R ₆ Fe ₁₁ Ga ₃ phase of a tetragonal compound is said to exist.
However, there is no description about the phase having the above-mentioned composition discovered in the present invention, and the crystal structure and magnetism of this phase are not yet clear.

The improvement of the coercive force due to the existence of the R-Fe-Ga-Al phase is considered to be because this phase exists between the main phase grains and promotes the magnetic separation between the main phase grains. Further, the amount of Ga added necessary for the existence of the R—Fe—Ga—Al phase of the present invention is smaller than that for the case where the R ₆ Fe ₁₁ Ga ₃ phase is present. In other words, R ₆ Fe ₁₁ G
atomic ratio of Ga in a ₃ phase is, R-Fe in the present invention
It is almost three times the atomic ratio of Ga in the -Ga-Al phase.
Therefore, even if the addition amount of Ga is the same as the alloy composition, R
₆ Fe ₁₁ Ga _3-phase also increases the R-Fe-Ga-Al phase it is present volume ratio of the present invention than to promote separation of the main phase grains, increasing the effect of improving the coercive force. Furthermore, since the amount of Ga added can be suppressed to a low level, the decrease in magnetization is small and a high energy product can be obtained. Also expensive Ga
By reducing the addition amount of, it is possible to reduce the cost.

Considering the use of magnets at high temperatures, D
A high coercive force by y substitution is an effective means. But,
When the Dy substitution amount is 10% or more of the Pr amount, coarsening of the main phase crystal grains in the cast structure becomes noticeable. For this reason, the orientation of the main phase grains due to hot rolling becomes insufficient, the magnet characteristics deteriorate, and it becomes unsuitable for actual use. If the substitution amount is 4 to 10% of the Pr amount, iHc
Since ≧ 20 kOe or more, a magnet excellent in use at high temperature can be obtained.

Next, a manufacturing method for obtaining the magnet according to the present invention will be described. First, an alloy having a desired composition is melted and cast to produce an ingot. This ingot is hot-rolled in the temperature range of 800 to 1100 ° C. as shown in JP-A-6-244012, page 3, column 4, lines 28-33. After that, heat treatment is performed in a temperature range of 900 to 1050 ° C. to obtain high magnetic characteristics, especially high coercive force. When the heat treatment is performed at a temperature lower than 900 ° C., α-Fe existing in the main phase grains remains, and it is considered that the coercive force becomes low. Further, when the heat treatment is performed at a temperature higher than 1050 ° C., the coarsening of the main phase crystal grains becomes obvious, which also results in a low coercive force. After heat treatment at 900 to 1050 ° C and cooling, R is already present in the magnet structure.
Since the -Fe-Ga-Al phase is formed, the separation of the main phase grains is promoted and a high coercive force is obtained. After the above heat treatment, a coercive force is further improved by applying heat treatment in the temperature range of 450 to 600 ° C.

[0023]

【Example】

(Example 1) Pr, Fe and Ga having a purity of 99.9%, 20
Using ferroboron containing B of 2 wt% and Al of 2 wt% as a raw material, a predetermined weight is weighed and Ar is placed in a high frequency melting furnace.
It was melted in the atmosphere and cast in a copper mold to obtain a 5 kg ingot. Table 1 shows the results of component analysis of each alloy. For the sake of convenience, the amount of the unavoidable impurity element is Fe.
It was expressed by including it in the atomic% value. Further, in the table, the amount of residual Fe (numerical value obtained by subtracting 14 times the atomic% value of B from the atomic% value of Fe) is also shown.

[0024]

[Table 1]

Of these alloys, the alloys of Nos. 2, 3, 5 and 6 have a composition within the range defined by the above-mentioned Japanese Patent Application Laid-Open No. 4-105305, but the residual Fe content is negative. It is a value.

Each alloy ingot shown in Table 1 was cut into a predetermined size and then enclosed in a ss41 capsule at 975 ° C.
Was hot-rolled. The total processing rate during rolling is 75%
And After rolling and cooling, take out the rolled magnet material from the capsule and put it in an Ar atmosphere at 1025 ° C × 20h + 500 ° C ×
A two-step heat treatment of 2 hours was performed. After the heat treatment, the sample was cut out and the magnet characteristics were measured with a DC self-recording magnetometer. The obtained coercive force (iHc) and the residual Fe shown in Table 1.
The relationship with the amount is shown in FIG. As is clear from FIG. 1, the residual F
A magnet having a negative e content has a low coercive force of about 8 kOe, whereas a magnet having a positive residual Fe content has a high coercive force of 16 kOe or more.

As a result of observing the magnet structure of the sample in which the residual Fe content is positive and a high coercive force is obtained, the grain boundary phase contains a Pr-rich phase and a phase composed of Pr, Fe, Ga, and Al. On the contrary, it was confirmed that this phase does not exist in the low coercive force magnet structure in which the residual Fe content is negative.
As a result of the EPMA analysis of the magnet structure produced from the alloy 10, the quantitative analysis value of this phase is Pr: 34.5at%, F
e: 59.8 at%, Ga: 5.2 at%, Al: 0.5 at%.

Example 2 Pr _16.0 Fe _83.3-a B _a G
An ingot having a composition of a _0.5 Al _0.2 (4.4 ≦ a ≦ 5.8) was melted and cast in a high frequency melting furnace to obtain a 5 kg ingot. The obtained ingot is cut into a predetermined size and ss
After being encapsulated in 41-made capsules, the total processing rate is 7 at 975 ° C.
5% hot rolling was performed. After rolling and cooling, take out the rolled magnet material from the capsule and put it in an atmosphere of 1025
A two-stage heat treatment of ℃ × 20h + 500 ℃ × 2h was applied. The relationship between the obtained iHc, Hk (the strength of the magnetic field when the magnetization corresponds to 0.9Br in the demagnetization curve), (BH) max (maximum energy product), and the B amount (a) As shown in FIG. In the figure, the value of B content (5.55 atomic%) at which the residual Fe content becomes 0 in this alloy system is shown on the X axis. As is clear from the figure, when the amount of B is less than 4.8 atomic%, Pr ₂ Fe ₁₇ phase, which is a soft magnetic phase, appears so that the squareness is deteriorated and (BH) max is also a low value. Absent. Therefore, as shown in the present invention, high magnetic characteristics can be obtained in the region where the amount of B is 4.8 atom% or more and the amount of residual Fe is positive.

(Example 3) Pr _b Fe _94.1-b B _5.2 Ga
An alloy having a composition of _0.5 Al _0.2 (13.5 ≦ b ≦ 18.5) was melted and cast in a high frequency melting furnace to obtain a 5 kg ingot. The obtained ingot was cut into a predetermined size, enclosed in a capsule made of ss41, and hot-rolled at 975 ° C. with a total working rate of 75%. After rolling and cooling, take out the rolled magnet material from the capsule and put it in an Ar atmosphere at 1025 ° C x 20
A two-step heat treatment of h + 500 ° C. × 2 h was performed. IH obtained
FIG. 3 shows the relationship between the values of c, Hk, (BH) max and the Pr amount (b). In this composition range, the residual Fe amount is all positive.

As is clear from the figure, when Pr is 17.5 atomic% or more, the squareness (Hk) and (BH) max deteriorate.

Furthermore, 50 mm × 10 having the same composition
From 0 mm x 200 mm rolled magnet block to 4 mm x 10 mm
A × 20 mm plate sample was cut out. FIG. 4 shows the relationship between the defect rate and the Pr amount in all the products when the cut-out plate magnets having cracks or cracks are visually judged to be defective. As is clear from the figure, when the Pr content is less than 15 atomic%, the product defect rate is significantly increased.

From the above, in order to obtain high magnetic characteristics without impairing the mechanical strength, the Pr amount should be 15
It is preferably in the range of atomic% to 17.5 atomic%.

(Example 4) Pr ₁₆ Fe _78.6-c B _5.2 G
An alloy having a composition of a _c Al _0.2 (0 ≦ c ≦ 1.5) was melted and cast in a high frequency melting furnace to obtain a 5 kg ingot. The obtained ingot was cut into a predetermined size, enclosed in a capsule made of ss41, and hot-rolled at 975 ° C. with a total working rate of 75%. After rolling and cooling, take out the rolled magnet material from the capsule and put it in an Ar atmosphere at 1025 ° C x 20h + 5
A two-stage heat treatment of 00 ° C x 2h was performed. Obtained iHc, H
FIG. 5 shows the relationship between the values of k and (BH) max and the Ga amount (c).
Shown in

As is clear from the figure, the coercive force is significantly increased by adding Ga in an amount of 0.1 atomic% or more. Further, even if 0.8 atomic% or more is added, the elongation of coercive force is saturated, and conversely, the decrease in energy product due to the decrease in magnetization becomes remarkable.

Example 5 (Pr _0.8 Nd _0.2 ) ₁₆ Fe
Dissolving _{83.3-d B d Ga 0.5 Al} 0.2 (4.4 ≦ d ≦ 5.8) comprising the alloy composition at a high frequency melting furnace to obtain ingots cast 5 kg. The obtained ingot was cut into a predetermined size, enclosed in a capsule made of ss41, and hot-rolled at 975 ° C. with a total working rate of 75%. After rolling and cooling, the rolled magnet material was taken out from the capsule and subjected to a two-step heat treatment of 1025 ° C. × 20 h + 500 ° C. × 2 h in an Ar atmosphere. FIG. 6 shows the relationship between the obtained iHc, Hk, (BH) max values and the B amount (d).

Similar to the case of only Pr, a magnet partially substituted with Nd can obtain high magnetic characteristics in the composition range defined by the present invention. As a result of observing the magnet structure with d = 5.2, Pr, Nd, Fe, Ga, A as grain boundary phases were observed.
The phase consisting of 1 exists, and as a result of analyzing this phase by EPMA, Pr: 28.4 atom%, Nd: 7.1 atom%, Fe: 58.2 atom%, Ga: 5.8 atom% , A
1: It was 0.5 atomic%.

Example 6 (Pr _1-x Dy _x ) ₁₆ Fe
An alloy having a composition of _78.1 B _5.2 Ga _0.5 Al _0.2 (0 ≦ x ≦ 0.15) was melted and cast in a high frequency melting furnace to obtain a 5 kg ingot. The obtained ingot was cut into a predetermined size, enclosed in a capsule made of ss41, and hot-rolled at 975 ° C. with a total working rate of 75%. After rolling and cooling, the rolled magnet material was taken out from the capsule and subjected to a two-step heat treatment of 1025 ° C. × 20 h + 500 ° C. × 2 h in an Ar atmosphere. Obtained iHc, Hk, (BH) max values and Dy
FIG. 7 shows the relationship with the substitution amount (x).

As is apparent from the figure, by adding Dy, further improvement in iHc is achieved. However, when the value of x exceeds 0.10, coarsening of the cast structure becomes obvious, and the degree of orientation of the main phase grains and the squareness of the grains decrease, causing deterioration of (BH) max and Hk.

More preferably, if x is between 0.04 and 0.10, iHc> 20 kOe, and an excellent magnet can be obtained at high temperature. Moreover, as a result of observing the magnet structure of x = 0.05, as a grain boundary phase, Pr, Dy, Fe, Ga,
A phase consisting of Al is present, and as a result of analyzing this phase by EPMA, Pr: 33.2 atomic% and Dy: 1.8
Atomic%, Fe: 59.0 atomic%, Ga: 5.5 atomic%,
Al: It was 0.5 atomic%.

Example 7 Pr ₁₆ Fe _78.1 B _5.2 Ga
An alloy having a composition of _0.5 Al _{0.2 was} melted and cast in a high frequency melting furnace to obtain a 5 kg ingot. The obtained ingot was cut into a predetermined size, enclosed in a capsule made of ss41, and hot-rolled at 975 ° C. with a total working rate of 75%. After slow cooling, the rolled magnet material was taken out from the capsule.
Samples were cut from this rolled material and the magnetic properties were measured (as roll). Further, the rolled material was subjected to a heat treatment for 20 hours at each temperature of 800 to 1150 ° C. in Ar atmosphere, and the magnetic characteristics were measured. IHc and H obtained in FIG.
The relationship between the values of k and (BH) max and the heat treatment temperature is shown.

As can be seen from the figure, after rolling, it is 900 to 1050.
High magnetic properties can be obtained by performing heat treatment in the range of ° C.

Example 8 The same rolled magnet material as in Example 8 was heat-treated at 1025 ° C. for 20 hours and then further processed.
Heat treatment was performed for 2 hours at each temperature of 350 to 800 ° C. FIG. 9 shows the relationship between the coercive force (iHc) obtained at this time and the second stage heat treatment temperature.

As is clear from the figure, when the heat treatment is performed in the temperature range of 450 to 600 ° C. in addition to the high temperature heat treatment, the effect of improving the coercive force becomes more apparent.

[0044]

Since the present invention is configured as described above, it has the following effects.

The composition of each alloying element in the R-Fe-B based magnet by the casting / hot rolling method, which has advantages such as mechanical strength superior to the sintered magnet and can produce a large magnet. By prescribing and by allowing the R-Fe-Ga-Al phase to exist as the grain boundary phase, it is possible to obtain higher magnetic characteristics than before.

Further, by setting the substitution amount of Dy within an appropriate range, it is possible to realize a higher coercive force and provide a magnet suitable for use at high temperatures.

As a method of manufacturing the magnet, it is possible to secure stable magnetic characteristics by optimizing the heat treatment after rolling.

[Brief description of drawings]

FIG. 1 is a graph showing the relationship between the amount of residual Fe and the coercive force (iHc).

[Figure 2] B amount of _{Pr 16.0 Fe 83.3-a B a} Ga 0.5 Al 0.2 (a) and relationship diagram of the magnetic properties.

FIG. 3 is a graph _showing the relationship between the Pr amount (b) and the magnetic characteristics in Pr _b Fe _94.1-b B _5.2 Ga _0.5 Al _0.2 .

FIG. 4 is a relational diagram between the Pr content (b) and the product defect rate in Pr _b Fe _94.1-b B _5.2 Ga _0.5 Al _0.2 .

FIG. 5 is a graph _showing the relationship between the amount of Ga (c) and magnetic properties in Pr ₁₆ Fe _78.6-c B _5.2 Ga _c Al _0.2 .

FIG. 6 (Pr _0.8 Nd _0.2 ) ₁₆ Fe _83.3-d B _d Ga _0.5
FIG. 4 is a diagram showing the relationship between the amount of B (d) and the magnetic properties of Al _0.2 .

FIG. 7: (Pr _1-x Dy _x ) ₁₆ Fe _78.1 B _5.2 Ga _0.5 A
FIG. 4 is a diagram showing the relationship between the Dy substitution amount (x) and the magnetic characteristics at l _0.2 .

FIG. 8 is a diagram _showing the relationship between the heat treatment temperature and the magnetic properties of Pr ₁₆ Fe _78.1 B _5.2 Ga _0.5 Al _0.2 .

FIG. 9 is a graph _showing the relationship between the second stage heat treatment temperature and the magnetic properties of Pr ₁₆ Fe _78.1 B _5.2 Ga _0.5 Al _0.2 .

Claims (6)

[Claims] 1. Pr, Fe, B, Ga, Al and impurities inevitable in production, Pr is 15.0 to 17.5 atomic%, Ga is 0.1 to 0.8 atomic%, and B content is 4.8 atom% or more, and the residual Fe amount (a value obtained by subtracting a value obtained by multiplying the atom% value of B by 14% from the atom% value of Fe) is a positive value,
A rare earth magnet having a Pr-Fe-Ga-Al phase in a magnet structure. 2. A rare earth magnet having a (Pr, Nd) -Fe-Ga-Al phase in the magnet structure, wherein a part of Pr in claim 1 is replaced with Nd. 3. 10% or less of the Pr amount according to claim 1 is D
by substituting y, and (Pr, Dy) -Fe- in the magnet structure.
A rare earth magnet having a Ga-Al phase. 4. The rare earth magnet according to claim 3, wherein 4 to 10% of the Pr amount is replaced with Dy. 5. The alloy is melted and cast to prepare an ingot, and the ingot is enclosed in a metal capsule and then 800
Hot rolled at a temperature of ~ 1100 ℃, then 900 ~ 1050 ℃
The method for producing a rare earth magnet according to claim 1, wherein the heat treatment is performed at the temperature of. 6. An alloy is melted and cast to prepare an ingot, and the ingot is enclosed in a metal capsule, and then 800
Hot rolled at a temperature of ~ 1100 ℃, then 900 ~ 1050 ℃
The method for producing a rare earth magnet according to any one of claims 1 to 4, wherein the heat treatment is performed at a temperature of 5 to 60 ° C, and the heat treatment is further performed at a temperature range of 450 to 600 ° C.