JP3441197B2 - Paste joining material for brazing - Google Patents

Description

Detailed Description of the Invention

[0001]

The present invention relates to a for brazing pasty bonding material.

[0002]

2. Description of the Related Art Permanent magnets containing rare earth elements are extremely brittle and have poor machinability. When exposed to high temperatures, the metal structure changes, and the magnetic properties , especially coercive force, change accordingly.
_It has a property that _I H _c (magnetization strength = 0) decreases.

Therefore, for example, when attaching a permanent magnet to a metal rotor of a motor, it is not possible to adopt attachment means such as an insertion structure, screwing, welding, etc. Therefore, an adhesive has been conventionally used.

[0004]

However, the use of an adhesive causes problems that the adhesive strength is low because the wettability of the permanent magnet is poor, and that the adhesive strength is significantly reduced as the temperature rises. Under such circumstances, it is impossible to meet the demand for high-speed rotation of the motor.

In view of the above, the present invention has been made to contain a rare earth element.
The permanent magnet holding force between the permanent magnet and the dissimilar metal member _I H
It is an object of the present invention to provide the paste-like bonding material that can be brazed firmly without reducing _c .

[0006]

A paste-like bonding material for brazing according to the present invention comprises a permanent magnet containing a rare earth element and a dissimilar metal.
In order to braze the metal member, the coercive force _I H _{c of the} permanent magnet
One state and ing, is composed of a rare earth element-based alloy of liquid phase and solid-liquid coexisting state at a heating temperature that may avoid a decrease in
An alloy powder, and more constructed as thermally decomposing binder under heating with binding between particles mutually the alloy powder before
The rare earth element-based alloy includes alloy element AE and the balance rare earth element.
And the synthetic element AE is Cu, Al, Ga, C
o, Fe, Ag, Ni, Au, Mn, Zn, Pd, S
At least one selected from n, Sb, Pb, Bi, Ge and In , the content of which is 5 atomic% ≦ AE
≦ 50 atomic% , and the rare earth element is Y, La, C
e, Pr, Nd, Sm, Eu, Gd, Tb, Dy, H
o, Er, Tm, Yb, Lu, misch metal and di
Characterized by at least one Der Rukoto selected from the gym.

[0007]

With the above construction, the permanent magnetism by brazing is used.
It is possible to avoid a decrease in the coercive force _I H _c of the stone .

Since the bonding material is a paste, it is permanent.
Even if the joining surface of the magnet and the dissimilar metal member is complicated, the joining material can be uniformly applied to the entire joining surface uniformly and easily to the required thickness. It enters into the recess and is fixed there. Liquid phase arising from the alloy powder based on rare earth elements is under heat, the liquid phase is a high activity, with a large junction area of the permanent magnet or the like so exhibits excellent wettability with respect to the permanent magnet or the like Can braze firmly. Removal of the binder is carried out by heating after coating or carried out under the heating, or the bonding material junction surface. In the latter case, an alloy powder layer is formed on the joint surface.

However, in the rare earth element-based alloy, the content of the alloy element AE is AE <5 atomic% or A
When E> 50 atomic%, the volume fraction Vf of the liquid phase in the solid-liquid coexisting state becomes low, so that the bonding strength decreases. From this, it is desirable that the content of the alloy element AE is set so as to have a eutectic composition or a composition close thereto in relation to the rare earth element. In addition, two or more alloy elements AE
In the case of containing, the total content thereof is 5 atomic% ≦
AE ≦ 50 atomic%.

[0010]

EXAMPLE A paste-like bonding material for brazing is composed of an alloy powder of a rare earth element-based alloy and a binder.

[0011] The rare earth element-based alloy constituting the alloy powder,
And rare earth elements is the main component, composed of an alloy element AE to perform the rare earth element and the eutectic reaction. Rare earth elements are Y, La, Ce, Pr, Nd, Sm, Eu, Gd, T
b, Dy, Ho, Er, Tm, Yb, Lu , Mishme
It is at least one selected from tar and zidim . Or alloy element AE is, Cu, Al, Ga, Co , F
e, Ag, Ni, Au, Mn, Zn, Pd, Sn, S
It is at least one selected from b, Pb, Bi, Ge and In. The content of the alloying element AE is 5 atom%.
≦ AE ≦ 50 atomic% is set.

Table 1 shows examples of eutectic alloys in rare earth element-based alloys.

[0013]

[Table 1]

Further, examples of the hypoeutectic and hypereutectic alloys in the rare earth element-based alloys include the following. In each chemical formula, the unit of the numerical value is atomic% (the same applies hereinafter). Nd ₆₀ Cu ₄₀ alloy, Nd ₈₀ Cu ₂₀ alloy, Nd ₅₀ C
u ₅₀ alloy, Nd ₉₀ Al ₁₀ alloy, Nd ₈₀ Co ₂₀ alloy, Sm
₇₅ Cu ₂₅ alloy, Sm ₆₅ Cu ₃₅ alloy, La ₈₅ Ga ₁₅ alloy.
Further, examples of the ternary alloys include Nd ₆₅ Fe ₅ Cu ₃₀ alloy (liquid phase generation temperature 510 ° C.) and Nd ₇₀ Cu ₂₅ Al ₅ alloy (liquid phase generation temperature 474 ° C.).

When brazing a permanent magnet and a dissimilar metal member, these members are superposed on each other via a paste-like bonding material or an alloy powder layer from which a binder has been pyrolyzed and removed, and then the superposed product is heated in vacuum. A method is employed in which the alloy powder is placed in a furnace, the alloy powder is brought into a liquid phase state or a solid-liquid coexisting state under heating, and then the furnace is cooled.

[0016] In this case, the heating temperature varies depending on the composition of the alloy powder, various rare earth element-based alloy of the composition during brazing because the hand-liquid phase state or solid-liquid coexisting state at a relatively low heating temperature It does not change the characteristics of the permanent magnet or the like.

Since the bonding material is a paste, it is permanent.
Even if the joining surface of the magnet and the dissimilar metal member is complicated, the joining material can be uniformly applied to the entire joining surface uniformly and easily to the required thickness. It enters into the recess and is fixed there. The liquid phase generated from the alloy powder containing a rare earth element as a main component under heating has a high activity and is a permanent magnet containing rare earth elements such as NbFeB permanent magnets.
Hisako magnet (very wettable to adhesives and normal brazing materials
Bad) and dissimilar metal parts of various materials, eg steel parts
Since the material exhibits excellent wettability, a permanent magnet or the like can be firmly brazed with a wide bonding area. When the paste-like bonding material is applied and then heated, the binder is thermally decomposed and removed under the heating.

[0018] The heating time h is permanent if it is too long
Since the characteristics of the permanent magnet and the like are changed, h ≦ 10 hours is desirable, and h ≦ 1 hour from the viewpoint of productivity improvement.

The grain size D of the alloy powder is the usual thickness t of the joining layer formed of the joining material, that is, 10 μm ≦ t ≦ 100.
Considering μm, 1 μm ≦ D ≦ 100 μm is appropriate. In this case, when D <1 μm, the handleability and productivity of the alloy powder deteriorate, while when D> 100 μm, it becomes difficult to adjust the thickness of the bonding layer.

All particles of the alloy powder may be crystalline particles, but in order to further enhance the strength of the bonding layer, as the alloy powder, the volume fraction Vf of amorphous particles is Vf.
It is preferable to use a material of ≧ 50%.

The reason for this is that in the amorphous particles, there is no grain boundary layer that serves as the starting point of oxidation, so that the oxidation resistance is remarkably higher than that of crystalline particles, and the inclusion of oxides is minimal. Moreover, there is no segregation and the composition is uniform.

Mechanical grinding, jet milling, mechanical alloying and the like are applied to the production of the alloy powder consisting of aggregates of crystalline particles. The average particle diameter Dm of the alloy powder varies depending on the conditions, but in the case of mechanical grinding, it is usually 20 μm ≦ Dm ≦ 50.
μm, for jet milling usually 1 μm ≦ Dm ≦ 5μ
m, in the case of mechanical alloying usually 20 μm ≦ Dm ≦
It is 50 μm.

Amorphous particles alone or volume fraction V
In the production of alloy powder containing Vf ≧ 50% at f, a liquid quenching method, for example, ultrasonic gas atomization or centrifugal atomization method is applied. In this case, although the average particle diameter Dm of the alloy powder varies depending on the conditions, it is usually 40 μm ≦ Dm ≦ 50 μm, and generally, the particles having the particle diameter D of D ≦ 32 μm are amorphous particles.

The binder is used to bond the particles of the alloy powder to each other, and must be decomposed at a temperature equal to or lower than the heating temperature T during brazing.
From this, a binder that basically contains a synthetic resin component and a solvent is used, and if necessary, a surfactant is added to improve the dispersibility of the alloy powder.

The synthetic resin component comprises acrylic resin, ethyl cellulose and the like. As the solvent, toluene, α-terpineol or the like is used. As the surfactant, alkylbenzene sulfonate, alkylamino acid, etc. are used.

The blending amount of each component varies depending on the coating conditions and the like, but the synthetic resin component SR is usually 10% by weight ≦ SR ≦ 2.
0% by weight, the solvent SO is 10% by weight ≦ SO ≦ 20% by weight,
Surfactant SA is 1% by weight ≦ SA ≦ 3% by weight. [Example 1] [A] Production of paste-like bonding material Nd ₇₀ Cu ₃₀ alloy having a eutectic composition was mixed with Nd having a purity of 99.9% and Cu having a purity of 99.9% as shown in FIG. It was weighed as obtained, and then the weighed material was melted using a vacuum melting furnace, and then cast to obtain an ingot.

Using the ingot made of this Nd ₇₀ Cu ₃₀ alloy, mechanical grinding was performed by the following method. (A) The ingot was roughly crushed using a stamp mill. (B) Planetary ball mill (commodity: JIS SUS316) with a weight ratio of coarsely pulverized product and steel balls (material: JIS SUS316) with a diameter of approximately 9 mm (3/8 inch) It was placed in a steel pot (material: JIS SUS316) having a name of Frish P5). (C) The inside of the pot was evacuated to a vacuum degree of 10 ⁻⁴ Torr and then replaced with dry argon gas. (D) Fine pulverization was performed under the conditions of revolution speed 150 rpm and milling time 1 hour. (E) The alloy powder was dry-collected in the glove box.

The alloy powder thus produced had a large variation in particle size such that the minimum particle size was several μm and the maximum particle size was about 100 μm.

Then, the alloy powder was subjected to a sieving treatment to obtain an alloy powder having a particle size D of D ≦ 32 μm. This alloy powder was made of Nd ₇₀ Cu ₃₀ alloy, and all the particles were crystalline particles.

Then 70% by weight of crystalline Nd ₇₀ Cu ₃₀
The alloy powder (D ≦ 32 μm), 15% by weight of acrylic resin and 15% by weight of toluene were sufficiently stirred in the glove box, whereby a paste-like bonding material was obtained. [B] Brazing work As a dissimilar metal member, a cold-rolled steel plate 1 having a thickness of 0.3 mm is laminated as shown in FIG.
A rectangular parallelepiped laminated body 2 having a length of 15 mm and a length of 15 mm was selected. In this laminated body 2, the caulking means 3 is used for joining the steel plates 1. Further, the through hole 4 of the laminated body 2 is used for connection with the chuck in the tensile test.

In the laminated body 2, a paste-like joining material having a thickness of about 70 is formed on the joining surface 5 formed by the end faces of the steel plates 1.
μm, and then the paste-like bonding material is dried under the condition of 80 ° C. for 1 hour to remove toluene, and then the paste-like bonding material is thermally decomposed, that is, the temperature rising rate is 10 in an argon gas atmosphere. The acrylic resin was removed by raising the temperature at 500 ° C./min to 500 ° C. and then holding the temperature for 30 minutes.

As a result, as shown in FIG.
The joining surface 5 of the, since moderate diffusion bonding between particles mutually crystalline Nd ₇₀ Cu ₃₀ alloy powder occurs, crystalline Nd ₇₀ Cu ₃₀ alloy powder layer 6 having a thickness of about 50μm was formed . The crystalline Nd ₇₀ Cu ₃₀ alloy powder layer 6 is relatively dense, and this is because the acrylic resin was thermally decomposed slowly because the temperature rising rate was set as described above.

As the permanent magnet , an NdFeB system permanent magnet (product name: NEOMAX-28UH, manufactured by Sumitomo Special Metals Co., Ltd.) 7 having a length of 10 mm, a width of 10 mm and a thickness of 3 mm was selected.

As shown in FIG. 3, one layered body 2 has a crystalline Nd ₇₀ Cu ₃₀ alloy powder layer 6 on which a permanent magnet 7 is provided, and another permanent body 7 has another layered body 2 formed thereon. Quality Nd
_{The 70} Cu ₃₀ alloy powder layer 6 was faced downward to overlap with each other to prepare an overlapped product. Then, the stack is placed in a vacuum heating furnace, and a heating step of heating temperature T = 530 ° C. and a heating time h = 30 minutes, followed by a cooling step of furnace cooling, is performed, as shown in FIG. A bonded body 9 was obtained by brazing the two magnets 2 and 7 so that the permanent magnet 7 was sandwiched between the two laminated bodies 2 via a bonding layer 8 made of an Nd ₇₀ Cu ₃₀ alloy.
In this brazing process, the heating temperature T is T = 530 ° C.
Since the eutectic point of 520 ° C. shown in FIG. 1 is exceeded, the crystalline Nd ₇₀ Cu ₃₀ alloy powder has a eutectic composition and thus is in a liquid phase state. In this case, the thickness of the bonding layer 8 is 2
It was 0 μm.

For comparison, the ingot was cut by a micro-cutter to produce a thin plate-like bonding material made of Nd ₇₀ Cu ₃₀ alloy and having a length of 10 mm, a width of 10 mm and a thickness of 0.25 mm. A joined body having the same structure as the joined body 9 shown in FIG. 4 was obtained by the same method as described above using the linear joining material. The thickness of the bonding layer in this case was 60 μm.

For comparison, a permanent magnet 7 similar to the above and two laminates 2 similar to the above are laminated with an epoxy resin adhesive (manufactured by Japan Ciba-Gaigi Co., trade name Araldide) on top of each other. The thing was made. Then, the stack is placed in a drying oven and heated to a heating temperature of 200
A joining process consisting of a heating step at a temperature of 60 ° C. and a heating time of 60 minutes followed by furnace cooling was performed to obtain a joined body in which the two laminated bodies 2 and the permanent magnet 1 were joined via an epoxy resin adhesive.

Tensile tests were performed on the bonded body 9 using the paste-like bonding material, the bonded body using the thin plate-shaped bonding material and the bonded body using the epoxy resin adhesive at room temperature and under heating at 150 ° C. The results shown in Table 2 were obtained.

[0038]

[Table 2]

As is clear from Table 2, the bonded body 8 using the paste-like bonding material has a higher bonding strength than the bonded body using the epoxy resin adhesive at room temperature and under heating at 150 ° C. The joint strength was almost the same under both environments, and the variation was small. The jointed body using the adhesive has a low joint strength at room temperature and has a large variation, and the joint strength decreases to one-third of that at room temperature when heated at 150 ° C.

As is clear from Table 2, the bonded body 8 using the paste-like bonding material has higher bonding strength at room temperature and under heating at 150 ° C. than the bonded body using the thin plate-shaped bonding material. . This is because the paste-like bonding material not only adheres to the end faces of the steel plates 1 on the bonding surface 5 of the laminate 2 in the applied state but also enters the gap between the adjacent steel plates 1, so that the crystal easy liquid phase resulting from the quality Nd ₇₀ Cu ₃₀ alloy powder resulting wet the bonding surfaces 5, also it has also been extended deposition area of the liquid phase, crystalline Nd ₇₀ Cu ₃₀ alloy powder covered by an acrylic resin Therefore, the progress of the oxidation is suppressed, and as a result, the bonding layer 8 has a small amount of oxide that causes a reduction in the bonding strength. Further, since the thickness of the crystalline Nd ₇₀ Cu ₃₀ alloy powder layer 6 is thin, there is an advantage that the amount of Nd ₇₀ Cu ₃₀ alloy eroded after the brazing treatment is small and therefore the post treatment is easy.

When the heating temperature T during brazing is T> 650 ° C., the permanent magnets 7 containing rare earth elements such as NdFeB type permanent magnets and SmCo type permanent magnets have magnetic properties, especially coercive force _I H _c ( The strength of magnetization = 0) tends to decrease.
However, the residual magnetic flux density Br and the coercive force _B H _c (magnetic flux density B = 0) hardly change, and therefore the maximum magnetic energy product (BH) max is substantially constant. In the brazing process using the paste-like joining material, the heating temperature T is T
= 530 ° C. and T ≦ 650 ° C., the magnetic characteristics of the permanent magnet 7 are not changed.

The poor wettability of the permanent magnet 7 is due to the presence of a phase having a high rare earth element concentration, that is, a high Nd concentration in this embodiment at the crystal grain boundary. In the brazing process using the paste-like bonding material, the Nd ₇₀ Cu
_{The 30} alloy powder is in a liquid phase state, and the liquid phase containing Nd as a main component is highly active, and N existing in the crystal grain boundary is present.
Since the main component is common to the phase having a high d concentration, the wettability to the permanent magnet 7 is excellent, and the wettability to the laminate 2 made of the steel sheet 1 is also very good due to the high activation. .

Therefore, by using the paste-like bonding material as described above, the permanent magnet 7 and the laminated body 2 can be firmly bonded without impairing the magnetic characteristics of the permanent magnet 7.

The joining technique is applied to the joining of the permanent magnet 7 to the laminated core of the rotor in the motor as a rotary electric machine, and enables the realization of a high-speed rotation motor having a rotation speed of 10,000 rpm or more. Example 2 Commercially available Cu powder having a particle size of about 15 μm and commercially available particle size of about 300
The Nd powder of μm was weighed in a glove box so as to obtain an Nd ₇₀ Cu ₃₀ alloy having a eutectic composition, and C
A raw material powder consisting of u powder and Nd powder was obtained.

Using this raw material powder, mechanical alloying was performed by the following method. (A) Raw material powder and steel balls with a diameter of approximately 9 mm (3/8 inch) (material JIS SUS3
16) were put into a steel pot (material JIS SUS316) of a planetary ball mill (trade name: Frish P5) at a ratio of raw material powder: steel ball = 1: 20 by weight ratio. (B) The inside of the pot was evacuated to a vacuum degree of 10 ⁻⁴ Torr and then replaced with dry argon gas. (C) Revolution speed 1
Grinding and pressure bonding were repeated under conditions of 50 rpm and milling time of 200 hours. In this case, if the milling time is short, N
d does not react with Cu. The NdCu phase starts to be generated in about 100 hours, but the milling time is required to be 200 hours in order to eliminate the Cu phase and generate a mixed phase of the Nd phase and the NdCu phase which causes a eutectic reaction. (D) The alloy powder was dry-collected in the glove box.

The alloy powder produced in this manner had a large variation in particle size such that the minimum particle size was several μm and the maximum particle size was about 100 μm.

Then, the alloy powder was subjected to a sieving treatment to obtain an alloy powder having a particle size D of D ≦ 32 μm. This alloy powder was made of Nd ₇₀ Cu ₃₀ alloy, and all the particles were crystalline particles.

Then, crystalline Nd ₇₀ Cu ₃₀ alloy powder (D
≦ 32 μm) and in the same manner as in Example 1
A paste-like bonding material having the same composition as that of was obtained.

After that, the paste-like bonding material and the laminate 2 and the permanent magnet 7 similar to those in the first embodiment were used, and the first embodiment was used.
The brazing work is performed under the same conditions as in FIG.
A joined body having the same structure as was obtained.

A tensile test was conducted on this bonded body under the same conditions as in Example 1, and the results shown in Table 3 were obtained. Table 3
For comparison, the data in the case where the paste-like bonding material containing the crystalline Nd ₇₀ Cu ₃₀ alloy powder of Example 1 is used is also shown in FIG.

[0051]

[Table 3]

As is clear from Table 3, even when the crystalline Nd ₇₀ Cu ₃₀ alloy powder obtained by mechanical alloying is used, the bonding strength equivalent to that of mechanical grinding can be obtained. [Example 3] Using the ingot made of the Nd ₇₀ Cu ₃₀ alloy of Example 1, ultrasonic gas atomization was performed by the following method.
(A) An ingot was put into a graphite crucible, and high-frequency melting was performed in an inert gas atmosphere to prepare a molten metal. (B) A molten metal is made to flow down through a nozzle hole of a quartz nozzle having a diameter of 1.5 mm, and a pressure of 10 is applied to the flowing down melt.
Nd ₇₀ C by injecting 0 kgf / cm ² cooling helium gas
At the same time as obtaining the u ₃₀ alloy powder, it was rapidly solidified.

The Nd ₇₀ Cu ₃₀ alloy powder thus obtained had an average particle diameter Dm of 40 μm ≦ Dm ≦ 50 μm. Therefore, the Nd ₇₀ Cu ₃₀ alloy powder was subjected to a sieving treatment to obtain an Nd ₇₀ Cu ₃₀ alloy powder having a particle size D of D ≦ 32 μm.

[0054] Figure 5 shows the X-ray diffraction results of the Nd ₇₀ Cu ₃₀ alloy powder and Nd ₇₀ Cu ₃₀ alloy ingot having a particle diameter D ≦ 32 [mu] m, in the Nd ₇₀ Cu ₃₀ alloy powder 2 [Theta] ≒ 30
A wide halo pattern was observed at °.
It has been found that the Nd ₇₀ Cu ₃₀ alloy powder has an amorphous single-phase structure, and therefore the volume fraction Vf of the amorphous particles is Vf = 100%.

Then, using the amorphous Nd ₇₀ Cu ₃₀ alloy powder (D ≦ 32 μm), a paste-like bonding material having the same composition as in Example 1 was obtained in the same manner as in Example 1.

After that, the paste-like bonding material and the laminate 2 and the permanent magnet 7 similar to those in the first embodiment were used, and the first embodiment was used.
The brazing work is carried out under the same conditions as those of the laminated body 9 shown in FIG.
A joined body having the same structure as was obtained.

A tensile test was conducted on this joined body under the same conditions as in Example 1, and the results shown in Table 4 were obtained. Table 4
For comparison, the data in the case where the paste-like bonding material containing the crystalline Nd ₇₀ Cu ₃₀ alloy powder of Example 1 is used is also shown in FIG.

[0058]

[Table 4]

As is clear from Table 4, amorphous Nd ₇₀ C
The bonded body using the paste-shaped bonding material containing the u ₃₀ alloy powder has a crystalline N content at room temperature and under heating at 150 ° C.
Bonding strength is higher than that of a bonded body using a paste-like bonding material containing d ₇₀ Cu ₃₀ alloy powder. This is amorphous Nd ₇₀ C
This is because the u ₃₀ alloy powder has remarkably high oxidation resistance, a small amount of oxides are mixed, and the composition is uniform. Example 4 Using the ingot made of the Nd ₇₀ Cu ₃₀ alloy of Example 1, the centrifugal atomization method was performed by the following method. (A) An ingot was put into a graphite crucible, and high-frequency melting was performed in an inert gas atmosphere to prepare a molten metal.
(B) Molten metal is ejected from the nozzle hole of the quartz nozzle onto the tapered outer peripheral surface of a substantially frustoconical disk that rotates below, and droplets are formed by scattering the molten metal by the centrifugal force of the disk. Then, the droplets were rapidly solidified with helium gas for cooling to obtain Nd ₇₀ Cu ₃₀ alloy powder.

The conditions in this centrifugal atomization method are as follows. That is, the diameter of the nozzle hole is 0.3 mm, the pressure of the molten metal ejected from the nozzle hole is 1 kgf / cm ² , the structure of the disk is ZrO ₂ sprayed on the surface of the carbon body at low temperature, the large end diameter of the disk is 70 mm, the taper of the disk is Angle 150 °, disk rotation speed 15000 rpm, helium gas ejection pressure 10
It is kgf / cm ² .

The Nd ₇₀ Cu ₃₀ alloy powder thus obtained, unlike the gas atomized, contains spherical ones as well as flat ones, and the aspect ratio of the flat ones is 2-3. It was This aspect ratio was calculated as y / x when the vertical length was x, the horizontal length was y, and x <y on a flat plane. Nd ₇₀
The average particle diameter of Cu ₃₀ alloy powder (average value of horizontal length y for flat ones) Dm is 70 μm ≦ Dm ≦ 80 μm, and thus Nd ₇₀ Cu ₃₀ alloy powder is subjected to sieving treatment to form particles. An Nd ₇₀ Cu ₃₀ alloy powder having a diameter D of D ≦ 32 μm was obtained.

X-ray diffraction of this Nd ₇₀ Cu ₃₀ alloy powder having a particle size D ≦ 32 μm revealed that it had an amorphous single-phase structure as in Example 3.

Then, using the amorphous Nd ₇₀ Cu ₃₀ alloy powder (D ≦ 32 μm), a paste-like bonding material having the same composition as in Example 1 was obtained in the same manner as in Example 1.

After that, the paste-like bonding material and the laminate 2 and the permanent magnet 7 similar to those in the first embodiment were used, and the first embodiment was used.
The brazing work is performed under the same conditions as in FIG.
A joined body having the same structure as was obtained.

A tensile test was conducted on this joined body under the same conditions as in Example 1, and the results shown in Table 5 were obtained. Table 5
For comparison, the data in the case where the paste-like bonding material containing the amorphous Nd ₇₀ Cu ₃₀ alloy powder of Example 3 is used is also shown in FIG.

[0066]

[Table 5]

As is clear from Table 5, even when the amorphous Nd ₇₀ Cu ₃₀ alloy powder produced by the centrifugal atomization method is used, the bonding strength equivalent to that in the case of ultrasonic gas atomization can be obtained.

It should be noted that the removal of the solvent such as toluene and the removal of the synthetic resin component such as the acrylic resin are not indispensable prior to the brazing treatment as described above, and the removal is performed during the brazing treatment. It is also possible.

In joining the permanent magnet and the dissimilar metal member, from the viewpoint of improving the joining strength, the rare earth element contained in the permanent magnet and the main component of the alloy powder in the paste-like joining material are the same as those in the above-mentioned embodiment. It is desirable to match the rare earth element, but for example, when joining a permanent magnet containing Nd, an alloy powder containing La as a main component is used, or when connecting a permanent magnet containing Sm, Sm is a main component. In addition to the alloy powder containing Al, the alloying powder containing La, Ce, Nd, Pr or the like as a main component can be used to obtain a bonding strength substantially equal to the above .

[0070]

According to the present invention, it is configured as described above.
This allows permanent magnets containing rare earth elements and dissimilar metal parts.
The coercive force _I H _c of the permanent magnet is reduced when joining the material.
It is possible to provide a paste-like bonding material that can increase the bonding strength without causing it .

[Brief description of drawings]

FIG. 1 shows a main part of a Cu—Nd system phase diagram.

FIG. 2 is a perspective view of a laminated body.

FIG. 3 is a perspective view showing a superposition relationship between a laminated body and a permanent magnet.

FIG. 4 is a perspective view of a joined body.

FIG. 5 is an X-ray diffraction diagram of Nd ₇₀ Cu ₃₀ alloy powder and Nd ₇₀ Cu ₃₀ alloy ingot.

[Explanation of symbols]

Second stack (members of different metals) 6 crystalline Nd ₇₀ Cu ₃₀ alloy powder layer 7 permanent magnet 8 bonding layer 9 assembly

Continuation of the front page (56) Reference JP-A-4-270094 (JP, A) JP-A-6-15463 (JP, A) JP-A-5-135976 (JP, A) JP-A-3-87338 (JP , A) JP 3-75344 (JP, A) JP 8-112680 (JP, A) JP 8-52590 (JP, A) JP 8-118066 (JP, A) JP 60-40687 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B23K 35/24-35/32 H01F 41/02

Claims (3)

(57) [Claims] 1. A different kind of permanent magnet (7) containing a rare earth element.
The permanent magnet (7) for brazing the metal member (2)
Liquid state at a heating temperature that can avoid a decrease in coercive force _I H _c of
And one state and ing of the solid-liquid coexistence state, and the alloy powder is composed of rare earth element-based alloy is more structure and thermal decomposition binder under heating with binding between particles mutually the alloy powder, the rare earth Elemental alloys include alloy element AE
The balance is a rare earth element, and the synthetic element AE is Cu,
Al, Ga, Co, Fe, Ag, Ni, Au, Mn, Z
It is at least one selected from n, Pd, Sn, Sb, Pb, Bi, Ge and In , and its content is 5
Atomic% ≦ AE ≦ 50 atomic% , and the rare earth element is
Y, La, Ce, Pr, Nd, Sm, Eu, Gd, T
b, Dy, Ho, Er, Tm, Yb, Lu, Mischme
Brazing paste-like bonding material to at least one Der wherein Rukoto selected from tall and didymium. 2. The particle diameter D of the alloy powder is 1 μm ≦ D ≦ 1.
The paste-like bonding material for brazing according to claim 1, which has a thickness of 00 μm. 3. The paste-like bonding material for brazing according to claim 1, wherein a volume fraction Vf of amorphous particles in the alloy powder is Vf ≧ 50% .