JPH0919789A - Heating/joining of two kind members having different coefficient of thermal expansion - Google Patents

Abstract

PROBLEM TO BE SOLVED: To strongly heat/join a permanent magnet to a steel block having a coefficient of thermal expansion larger than the magnet while avoiding crack of permanent magnet. SOLUTION: A platy insert 5, in which a coefficient of thermal expansion is changed from small to large from one flat face (a) side toward the other flat side (b) side and a coefficient of thermal expansion at one flat face (a) side is larger than that of a permanent magnet and a coefficient of thermal expansion at the other flat face (b) side is smaller than that of a block body 3, is prepared. A laminated body is produced by interposing a brazing filler metal 7 as one flat face (a) of the insert 5 facing to the permanent magnet 2 between both 2, 5 and interposing a brazing filler metal 9 as the other flat face (b) side of insert 5 facing to the block body 3 between both 5, 3. Successively, by heating the laminated body, the permanent magnet 2, insert 5 and block body 3 are joined with a joining layer made of both brazing filler metals 8, 9. Crack of the permanent magnet 5 is avoided due to existence of the insert 5 and joining strength is improved with both joining layers.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of heating and joining two kinds of members having different thermal expansion coefficients, that is, a first member and a second member having a thermal expansion coefficient larger than that of the first member under heating. Regarding the method of joining.

[0002]

2. Description of the Related Art Conventionally, for example, when a permanent magnet containing a rare earth element as a first member and a steel mounting base as a second member are joined, a synthetic resin adhesive has been used (for example, (See Japanese Patent Publication No. 61-33339).

The reason why the synthetic resin adhesive is used in this way is that the permanent magnet containing a rare earth element is very brittle and thus has poor machinability, and the metal structure changes when exposed to high temperatures. This is because the magnetic characteristics are affected, and therefore, when a permanent magnet is mounted on a steel mounting base, it is not possible to adopt a mounting structure such as a manual insertion structure, screwing, or welding.

[0004]

However, in the case of joining with a synthetic resin adhesive, there is a problem in that the joining strength remarkably decreases as the temperature of the permanent magnet rises and the joining strength varies greatly, which makes quality control difficult. is there.

In view of the above, the present invention strongly joins the two types of members under heating and alleviates the thermal stress generated at the joint between the two members, so that the member having the smaller coefficient of thermal expansion is fragile. It is an object of the present invention to provide the above-mentioned heating joining method capable of avoiding the occurrence of cracks in the member in the cooling step.

[0006]

The present invention comprises a first member,
When joining the second member, which has a higher coefficient of thermal expansion than the first member, under heating, the plate-shaped insert has a coefficient of thermal expansion from a small flat surface side to a large flat surface side toward the other flat surface side. And the coefficient of thermal expansion on one flat surface side is
A member having a coefficient of thermal expansion larger than that of the member and a coefficient of thermal expansion of the other flat surface side smaller than that of the second member is prepared. A first brazing filler metal is provided between the flat surface and the joining surface, and the other flat surface is directed toward the joining surface of the second member, and a second brazing material is provided between the flat surface and the joining surface. With a brazing material interposed, a laminated body composed of a first member, a first brazing material, a plate-like insert, a second brazing material and a second member is produced, and then the laminated body is heated to produce the first member. And the plate-like insert are joined via a first joining layer made of the first brazing filler metal, and the second member and the plate-like insert are made of a second joint made of the second brazing filler metal. It is characterized in that they are joined via a layer.

By adopting the above-mentioned means, the first member and the plate-like insert are connected to each other via the first bonding layer and the second member.
Since the member and the plate-shaped insert can be firmly bonded to each other via the second bonding layer, it is possible to obtain a bonded body having high bonding strength between the first and second members.

When the plate-like insert is interposed between the first and second members, the coefficient of thermal expansion of them changes so as to gradually increase from the first member to the second member. Thereby, in the cooling step, the thermal stress generated in the joint portion between the two members due to the difference in thermal expansion coefficient between the first and second members can be relieved, so that even when the first member having the smaller thermal expansion coefficient is fragile. It is possible to avoid cracking in it.

The thermal expansion coefficients of the first and second brazing filler metals are
If their longitudinal elastic modulus E can be made small and their thickness is taken into consideration, it can be ignored.

[0010]

FIG. 1 shows an example of a bonded body 1. In this joined body 1, the first member is a permanent magnet 2 containing a rare earth element such as an NdFeB-based permanent magnet or an SmCo-based permanent magnet, and the second member is a carbon steel having a thermal expansion coefficient larger than that of the permanent magnet 2 ( It is a steel block body 3 made of a Fe-based alloy.

A joint portion 4 exists between the permanent magnet 2 and the steel block body 3. The joint portion 4 includes a plate-shaped insert 5 existing in the middle, a first bonding layer 6 existing between the permanent magnet 2 and the plate-shaped insert 5, and a second bonding layer existing between the steel block body 3 and the plate-shaped insert 5. And the bonding layer 7.

In the plate-like insert 5, the coefficient of thermal expansion changes from one flat surface a side on the permanent magnet 2 side to the other flat surface b side and changes from small to large, and the thermal expansion coefficient on one flat surface a side. Is larger than the coefficient of thermal expansion of the permanent magnet 2, and the coefficient of thermal expansion on the other flat surface b side is smaller than that of the steel block body 3.

The first and second joining layers 6 and 7 are such that the first and second brazing materials in the form of foil (or thin plates) generate a liquid phase under heating, that is, both brazing materials are completely liquid. It is formed by entering a phase state or a solid-liquid coexisting state in which a solid phase and a liquid phase coexist.

In the joining process, as shown in FIG.
In the plate-shaped insert 5, one flat surface a is directed to the joint surface c of the permanent magnet 2, the first foil-shaped brazing material 8 is interposed between the flat surface a and the joint surface c, and the other flat surface b Toward the joint surface d of the steel block body 3 and with the second foil-shaped brazing material 9 interposed between the flat surface b and the joint surface d, as shown in FIG. A laminate 10 including the material 8, the plate-like insert 5, the second brazing material 9 and the steel block body 3 is produced. Next, the laminated body 10 is placed in a vacuum heating furnace and heated to bring the first and second brazing materials 8 and 9 into a liquid phase state or a solid-liquid coexisting state, whereby the permanent magnet 2 and the plate-like shape are formed. The insert 5 is joined via the first joining layer 6 made of the first brazing material 8, and the steel block body 3 and the plate-like insert 5 are made up of the second joining layer made of the second brazing material 9. Join via 7. Thereafter, furnace cooling is performed to obtain the joined body 1.

When the heating time h in the joining process is too long, the permanent magnet 2 and the steel block body 3 are heated.
Therefore, h ≦ 10 hours is desirable, and from the viewpoint of improving productivity, h ≦ 1 hour.

By adopting the above-mentioned means, the permanent magnet 2 and the plate-like insert 5 via the first joining layer 6, and the steel block body 3 and the plate-like insert 5 through the second joining layer 7 are provided. Since they can be firmly bonded to each other through the joint, the bonded body 1 having a high bonding strength between the permanent magnet 2 and the steel block body 3
Can be obtained.

When the plate-like insert 5 is present between the permanent magnet 2 and the steel block body 3, the coefficient of thermal expansion of these 2, 3 and 5 is gradually increased from the permanent magnet 2 to the steel block body 3. Change. Thereby, in the cooling step, the thermal stress generated in the joint portion 4 due to the difference in the coefficient of thermal expansion between the permanent magnet 2 and the steel block body 3 can be relaxed,
Even if the permanent magnet 2 having a smaller coefficient of thermal expansion is brittle, it is possible to prevent the permanent magnet 2 from cracking.

The thermal expansion coefficients of the first and second brazing filler metals 8 and 9 can be neglected if the longitudinal elastic modulus E of them can be made small and their thicknesses are taken into consideration.

As the plate-like insert 5, for example, FIG.
As shown in FIG.
A clad plate made of alloy plates 11 _{1 to} 11 ₄ is used. The Ni content in each of the Fe-Ni alloy plates 11 _{1 to} 11 ₄ gradually decreases with increasing distance from the permanent magnet 2. In this case, the maximum Ni content Ni (max) is the first Fe
The Ni (max) of the —Ni alloy plate 11 ₁ is 36 atom%, and the minimum value Ni (min) is Ni (min) of the fourth Fe—Ni alloy plate 11 ₄ = 10 atom%.

Table 1 shows the composition and the coefficient of thermal expansion of each part of the plate-like insert 5.

[0021]

[Table 1]

As is apparent from FIG. 4 and Table 1, in the plate insert 5, the first Fe-Ni alloy plate 11 ₁ has one flat surface a and the fourth Fe-Ni alloy plate 11 ₄ has the other flat surface a. With surface b. Then, the coefficient of thermal expansion changes from small to large from one flat surface a side to the other flat surface b side.

As the first and second brazing filler metals 8 and 9, highly active ones composed of rare earth element alloys are used. In these brazing filler metals 8 and 9, it is desirable that the volume fraction Vf of the amorphous phase is 50% ≦ Vf ≦ 100%. The reason is as follows. That is, the amorphous phase has a significantly high oxidation resistance because there is no grain boundary layer that serves as the starting point of oxidation, and the amount of oxides is very small, and the composition is uniform without segregation. This is because such characteristics are effective for improving the strength of the first and second bonding layers 6 and 7.

In both brazing materials 8 and 9, the rare earth elements are Y, La, Ce, Pr, Nd, Sm, Eu, Gd and T.
At least one selected from b, Dy, Ho, Er, Tm, Yb and Lu is applicable, and they are used in the form of Mm (Misch metal) or Di (didymium) which is a single substance or a mixture. Further, the alloying element AE causes a eutectic reaction with a rare earth element, and the alloying element AE contains C
u, Al, Ga, Co, Fe, Ag, Ni, Au, M
At least one selected from n, Zn, Pd, Sn, Sb, Pb, Bi, Ge and In is applicable. The content of the alloy element AE is set to 5 atomic% ≦ AE ≦ 50 atomic%. When two or more kinds of alloying elements AE are contained, the total content thereof is 5 atom% ≦ AE ≦ 50 atom%. However, the content of the alloy element AE is AE> 50 atomic%.
In this case, the activity of the brazing filler metals 8 and 9 is impaired, while it becomes difficult to secure the liquid phase in the solid-liquid coexisting state when AE <5 atomic%.

Tables 2 and 3 show various rare earth element type eutectic alloys constituting the brazing filler metals 8 and 9 and their longitudinal elastic modulus E.

[0026]

[Table 2]

[0027]

[Table 3]

As the rare earth element-based hypo- and hypereutectic alloy,
The following can be mentioned. In each chemical formula,
The unit of the numerical value is atomic% (the same applies below). E is vertical
It means elastic modulus. (A) Nd₆₀Cu₄₀Alloy (E = 4500kgf / m
m^Two), Nd₇₅Cu_{twenty five}Alloy (E = 4000kgf / m
m^Two), Nd₈₀Cu₂₀Alloy (E = 3950kgf / m
m^Two), Nd ₅₀Cu₅₀Alloy (E = 9000kgf / mm^Two)
...... Liquid phase generation temperature 520 ° C (See Fig. 5) (b) Sm₇₅Cu_{twenty five}Alloy (E = 4000kgf / m
m^Two), Sm₆₅Cu₃₅Alloy (E = 4300kgf / mm^Two)
...... Liquid phase generation temperature 597 ° C (c) Nd₉₀Al_TenAlloy (E = 3850kgf / mm^Two,
Liquid phase generation temperature 634 ° C), Nd₈₀Co₂₀Alloy (E = 40
00kgf / mm^Two, Liquid phase generation temperature 599 ° C), La ₈₅Ga
_FifteenAlloy (E = 4000kgf / mm^Two, Liquid phase generation temperature 550
℃) Furthermore, as a ternary alloy, Nd₆₅Fe_FiveCu₃₀alloy
(E = 4200kgf / mm ^Two, Liquid phase generation temperature 501 ℃)
And Nd₇₀Cu_{twenty five}Al_FiveAlloy (E = 4000kgf / m
m^Two, Liquid phase generation temperature 474 ° C.). [Example 1] Nd having a purity of 99.9% and a purity of 99.9%
Of Cu and Al having a purity of 99.9% are Nd₇₀Cu_{twenty five}A
l_FiveWeigh it to obtain the alloy, and then weigh it.
It is melted using a vacuum melting furnace, then cast and
I got it.

Approximately 50 g of raw material was sampled from this ingot, and this was melted at high frequency with a quartz nozzle to prepare a molten metal.
Then, the molten metal was jetted from the slit of the quartz nozzle to the outer peripheral surface of the Cu cooling roll rotating at a high speed thereunder by the argon gas pressure to be ultra-quenched, and the width of 30 mm and the thickness of N of 20 μm.
A thin strip of d ₇₀ Cu ₂₅ Al ₅ alloy was obtained. This ribbon is homogeneous and has good continuity, so that the alloy having the above composition has a good ribbon forming property.

The manufacturing conditions in this case are as follows. That is, the inner diameter of the quartz nozzle is 40 mm, the size of the slit is the width
0.25mm, length 30mm, argon gas pressure 1.0kg
f / cm ² , melt temperature 800 ° C., distance between slit and cooling roll 1.0 mm, peripheral speed of cooling roll 33 m / sec
The cooling rate of the molten metal is about 10 ⁵ K / sec.

FIG. 6 shows the result of X-ray diffraction of the ribbon. In this ribbon, a wide halo pattern was observed at 2θ≈32 °, which indicates that the metal structure of the ribbon is an amorphous single-phase structure. It was found that the crystallization temperature Tx was Tx = 12.
It was 9.8 ° C. The liquid phase generation temperature Tm of the ribbon is Tm
= 474 ° C. to facilitate melting, and since the thin ribbon has high toughness, it can be bent by 180 ° in close contact and has excellent oxidation resistance without discoloration. Furthermore, under the above-mentioned manufacturing conditions, only the peripheral speed of the cooling roll was changed to change the thickness of the ribbon from 20 μm to 400 μm, and the critical thickness of the ribbon from which an amorphous single-phase structure was obtained was determined. The critical thickness was found to be 270 μm.

Next, a thin strip having a thickness of 100 μm is punched to form a foil shape having a length of 100 mm and a width of 20 mm as shown in FIG. , 9 were produced.

The first member is 100 mm long, 20 mm wide,
5mm thick NdFeB-based permanent magnet (Sumitomo Special Metals Co., Ltd.,
(Product name NEOMAX-28UH, Curie point 310 ° C)
No. 2 is selected, and carbon steel (JIS S
35C) and has a length of 20 mm, a width of 20 mm, and a length of 10
A 0 mm rectangular parallelepiped steel block body 3 was selected.

The thermal expansion coefficient of the NdFeB system permanent magnet 2 is about 1.0 × 10 ^-6 / ° C. (average value), and the thermal expansion coefficient of the steel block body 3 is about 12.2 × 10 ^-6 / ° C. there were.

FIG. 7 shows the relationship between the temperature and the coefficient of thermal expansion of the NdFeB system permanent magnet 2 and the steel block body 3. Figure 7
As is clear from the above, the NdFeB-based permanent magnet 2 has about 3
The NdFeB-based permanent magnet 2 has peculiarities that the coefficient of thermal expansion reverses at 10 ° C., and the change in coefficient of thermal expansion in the temperature range of about 310 ° C. or less is small, and the temperature drops in the cooling step after the heating step. It can be seen that the difference between the coefficient of thermal expansion of No. 1 and the coefficient of thermal expansion of the steel block body 3 rapidly increases.

Further, a plate-like insert 5 having a structure shown in Table 1 and FIG. 4 and having a length of 100 mm, a width of 20 mm and a thickness of 1.5 mm was prepared.

As shown in FIGS. 2 and 4, the steel block body 3
Of the second brazing material 9 on the upwardly facing joint surface d forming the rectangle of
On the second brazing filler metal 9 and the fourth Fe-Ni alloy plate 1
1 ₄ (the other flat surface b) of the plate-like insert 5 facing downward, and further the first brazing filler metal 8 on the first Fe-Ni alloy plate 11 ₁ (the one flat surface a) of the plate-like insert 5, Furthermore, the NdFeB-based permanent magnets 2 having the rectangular joint surface c facing downward were superposed on the first brazing filler metal 8 to fabricate the laminated body 10 shown in FIG.

Then, the laminated body 10 is placed in a vacuum heating furnace, and a heating step at a heating temperature T = 540 ° C. for a heating time h = 20 minutes and a subsequent cooling step consisting of furnace cooling are carried out, as shown in FIG. As shown, the NdFeB system permanent magnet 2 and the first
A crystalline first bonding layer 6 formed from the brazing material 8 of
A joined body 1 including the plate-like insert 5, the crystalline second joining layer 7 formed of the second brazing filler metal 9, and the steel block body 3 was obtained. In this joining process, the heating temperature T
Is T = 540 ° C. and the liquid phase generation temperature Tm of both brazing filler metals 8 and 9 exceeds 474 ° C., so that both brazing filler metals 8 and 9 are in a complete liquid phase state.

The joint body 1 thus obtained was visually observed to find that the NdFeB system permanent magnet 2 and the plate-like insert 5 were sufficiently joined together via the first joint layer 6, and The steel block body 3 and the plate-shaped insert 5 are second
It was found that they were sufficiently bonded through the bonding layer 7 of No.

No cracks were found in the NdFeB permanent magnet 2. As shown in FIG. 7, this is despite the fact that the thermal expansion coefficients of the NdFeB system permanent magnet 2 and the steel block body 3 differ greatly in the cooling process.
This is because the use of the plate-shaped insert 5 relaxes the thermal stress generated in the joint portion 4 in the cooling step. In particular, in the plate-like insert 5, the composition of the _first Fe—Ni alloy plate 11 ₁ closest to the NdFeB-based permanent magnet 2 is set to an invar composition, and the first Fe—Ni alloy plate 11 in a temperature range of about 310 ° C. or less is used. _When the thermal behavior of ₁ was approximated to that of the NdFeB system permanent magnet 2,
This is a major factor in avoiding the occurrence of cracks in the dFeB-based permanent magnet 2.

The permanent magnets containing rare earth elements such as the NdFeB permanent magnet 2 and the SmCo permanent magnet have their magnetic characteristics, especially the coercive force _I H _C (magnetization) when the heating temperature T during the joining process becomes T> 650 ° C. Strength I = 0) tends to decrease.
However, the residual magnetic flux density Br and coercive force _B H _C (magnetic flux density B = 0) Most unchanged, thus the maximum magnetic energy product (BH) max is substantially constant. In the joining process using both brazing filler metals 8 and 9, the heating temperature T is T = 540.
Since it is C and T ≦ 650 ° C., the magnetic characteristics of the NdFeB system permanent magnet 2 are not changed. [Embodiment 2] Amorphous foil-shaped first and second brazing filler metals 8 and 9 having the same composition as that described in Embodiment 1 and having a length of 20 mm, a width of 20 mm and a thickness of 100 μm. Two brazing filler metals 8 and 9 were prepared.

The NdFeB system permanent magnet 2 has the same structure as that described in Embodiment 1 and has a length of 20 mm and a width of 20.
mm, thickness 5 mm were prepared.

Further, as the steel block body 3, as in Example 1
The same material as the one described in, and 20 mm in height, 20 mm in width,
Two pieces with a length of 40 mm were prepared.

Furthermore, the plate-like insert 5 has the same structure as that described in the first embodiment and has a length of 20 mm and a width of 2 mm.
Two 0mm and 1.5mm thick ones were prepared.

As shown in FIG. 8 (also refer to FIG. 4), the second brazing material 9 is placed on the upward joining surface d forming the square of one steel block body 3, and the second brazing material 9 is placed on the second brazing material 9. , 4th Fe-N
The plate-shaped insert 5 with the i alloy plate 11 ₄ (the other bonding surface b) facing downward was placed on the first Fe-Ni alloy plate 11 ₁ (one flat surface a) of the plate-shaped insert 5 and the first brazing material 8 To
On the first brazing filler metal 8, the NdFeB-based permanent magnet 2 having one of the square-shaped joining surfaces c facing downward is provided on the other upward-facing joining surface c of the NdFeB-based permanent magnet 2 forming the square.
The brazing filler metal 8 of the first Fe-Ni alloy plate 11 ₁ (one flat surface a) facing downward on the first brazing filler metal 8 and the fourth Fe-Ni alloy of the plate-shaped insert 5 The second brazing filler metal 9 is applied on the plate 11 ₄ (the other flat surface b) to the second
Another steel block body 3 with the joint surface d facing downward was superposed on the brazing filler metal 9 to prepare a laminate, and a total of 20 laminates were prepared by the same procedure. The through holes 13 present in both steel block bodies 3 are used for connection with the chuck in the tensile test.

Next, each laminated body was placed in a vacuum heating furnace, and a heating step of heating temperature T = 540 ° C. and heating time h = 20 minutes, followed by a cooling step of furnace cooling, was carried out, as shown in FIG. 20 sandwiches 14 were obtained. Each sandwich 14 is composed of two bonded bodies 1 that share one NdFeB-based permanent magnet 2.

In this joining process, since the heating temperature T is set to T = 540 ° C. as in the first embodiment,
The brazing filler metals 8 and 9 having the liquid phase generation temperature Tm of Tm = 474 ° C. are in a completely liquid phase state.

Visual observation of each sandwich 14 thus obtained revealed that the NdFeB system permanent magnets 2 and the plate-like inserts 5 were sufficiently bonded via the first bonding layer 6. It was also found that the steel block body 3 and each plate-shaped insert 5 were sufficiently bonded via the second bonding layer 7. No cracks were found in the NdFeB permanent magnet 2.

For comparison, an NdFeB-based permanent magnet 2 similar to the above and two steel block bodies 3 similar to the above are used to form an epoxy resin adhesive (manufactured by Nippon Ciba-Gaigi Co., Ltd., trade name). NdF via Araldite)
The eB-based permanent magnets 2 were laminated so as to sandwich the permanent magnets 2 to produce a laminate, and a total of 20 laminates were produced by the same procedure. Next, these laminated bodies are placed in a drying oven and heated at a heating temperature of 20.
A heating process of 0 ° C. and a heating time of 60 minutes, followed by a cooling process consisting of furnace cooling, was performed, and two steel block bodies 3 and permanent magnets 2 were bonded to each other with an epoxy resin adhesive to form 20 pieces. A sandwich was obtained.

Tensile tests were carried out at room temperature for each of the sandwich-like materials 14 using the brazing filler metals 8 and 9 and the plate-like insert 5 and the sandwich-like materials 14 using the epoxy resin adhesive, and the remaining 10 About 150
When the tensile test was performed under heating at ℃, the results shown in Table 4 were obtained.

[0051]

[Table 4]

As is clear from Table 4, the sandwich-like article 14 using the brazing filler metals 8 and 9 and the plate-like insert 5
Has a higher bonding strength at room temperature and under heating at 150 ° C. than a sandwich using an epoxy resin-based adhesive, and the bonding strength is almost the same in both environments and its variation is small. The sandwich using the epoxy adhesive has a low bonding strength at room temperature and has a large variation, and the bonding strength is reduced to 1/3 of that at room temperature when heated at 150 ° C.

The poor wettability of permanent magnets containing rare earth elements such as the NdFeB permanent magnet 2 and the SmCo permanent magnet is
This is due to the presence of a phase having a high rare earth element concentration, that is, a high Nd concentration in this example, at the grain boundaries. In the joining process using the brazing filler metals 8 and 9, the brazing filler metals 8 and 9 are used.
Is in a liquid state and contains Nd ₇₀ C containing Nd as a main component.
Since the liquid phase generated from the u ₂₅ Al ₅ alloy is highly active and shares the main component with the phase having a high Nd concentration existing in the crystal grain boundaries, it has excellent wettability with respect to the NdFeB-based permanent magnet 2. Further, the wettability with respect to the steel block body 3 and the plate-like insert 5 is extremely good with the high activation.

The joining technique is applied to the joining of the NdFeB system permanent magnet 2 to the rotor body of the motor rotor as a rotating machine, and the rotation speed is 10000 rpm.
The above-described high-speed rotation motor can be realized.

[0055]

According to the present invention, by adopting the means specified as described above, two kinds of members having different thermal expansion coefficients can be firmly joined, and one having a small thermal expansion coefficient can be used. Even if the member is brittle, it is possible to prevent the member from cracking in the cooling step.

[Brief description of the drawings]

FIG. 1 is a partially enlarged front view of a joined body.

FIG. 2 is a perspective view showing an example of a superposing relationship of a permanent magnet, a brazing material, a plate-like insert, and a steel block body.

FIG. 3 is a side view of a laminated body.

FIG. 4 is a structural explanatory view of a plate-like insert.

FIG. 5 is a Cu—Nd system phase diagram.

FIG. 6 is an X-ray diffraction pattern of Nd ₇₀ Cu ₂₅ Al ₅ alloy.

FIG. 7 is a graph showing the relationship between temperature and coefficient of thermal expansion.

FIG. 8 is a perspective view showing another example of a superposition relationship of a permanent magnet, a brazing material, a plate-like insert, and a steel block body.

FIG. 9 is a perspective view of a sandwich.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Joined body 2 Permanent magnet (1st member) 3 Steel block body (2nd member) 5 Plate insert 6,7 1st, 2nd joining layer 8,9 1st, 2nd brazing material 10 Laminated body 11 _{1 to} 11 _{4 1st} to _4th Fe-Ni alloy plates a one joint surface b the other joint surface c, d joint surface

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display location H02K 1/27 501 H02K 1/27 501G 501B 15/03 15/03 Z

Claims (5)

[Claims] 1. A first member (2) and a first member (2) thereof.
When joining the second member (3) having a larger coefficient of thermal expansion than that of the plate-like insert (5) under heating, the flat insert (5) is moved from one flat surface (a) side to the other flat surface (b) side. The coefficient of thermal expansion changes from small to large, the coefficient of thermal expansion on one flat surface (a) side is larger than that of the first member (2), and the coefficient of thermal expansion on the other flat surface (b) side. A material having a coefficient of thermal expansion smaller than that of the second member (3) is prepared, and in the plate-like insert (5), the one flat surface (a) is used.
Toward the joint surface (c) of the first member (2), the first brazing filler metal (8) is interposed between the flat surface (a) and the joint surface (c), and the other flat surface ( b) is directed to the joint surface (d) of the second member (3) and a second brazing filler metal (9) is provided between the flat surface (b) and the joint surface (d).
The first member (2), the first brazing filler metal (8),
Plate-like insert (5), second brazing filler metal (9) and second
A laminated body (10) made of a member (3) is produced, and then the laminated body (10) is heated so that the first member (2) and the plate-like insert (5) are combined with the first brazing filler metal ( 8) is bonded through a first bonding layer (6) consisting of
A member (3) and the plate-like insert (5) are joined together via a second joining layer (7) made of the second brazing filler metal (9), and have different thermal expansion coefficients. A method for heating and joining two kinds of members. 2. The first member (2) is a permanent magnet containing a rare earth element, the second member (3) is made of an Fe alloy, and the first and second brazing filler metals (8, 9) are The method for heating and joining two kinds of members having different coefficients of thermal expansion according to claim 1, which are made of a rare earth element alloy. 3. The plate-shaped insert (5) has a plurality of Fs.
e-Ni alloy plate (11₁~ 11_Four) Clad plate
And each Fe-Ni alloy plate (11₁~ 11 _Four)
As the Ni content of the first member (2) increases,
Two kinds having different thermal expansion coefficients according to claim 2, which are gradually decreasing.
Method for heating and joining members. 4. The minimum value Ni (min) of the Ni content.
Is Ni (min) = 10 atomic%, and the maximum value Ni
The method for heating and joining two kinds of members having different thermal expansion coefficients according to claim 3, wherein (max) is Ni (max) = 36 atomic%. 5. The rare earth element in the first and second brazing filler metals (8, 9) is Y, La, Ce, Pr, Nd, S.
m, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb
And at least one selected from Lu, and the alloy element AE is Cu, Al, Ga, Co, Fe, Ag, N
i, Au, Mn, Zn, Pd, Sn, Sb, Pb, B
It is at least one selected from i, Ge and In, and the content of the alloying element AE is 5 atom% ≦ AE ≦ 50.
The method for heat-bonding two types of members having different thermal expansion coefficients according to claim 2, 3 or 4, wherein the method is atomic%.